Wednesday, 31 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Skydiver Aims to Jump from 120,000 Feet, Break the Sound Barrier

Posted: 31 Mar 2010 10:28 AM PDT


If you're planning to jump out of a plane at 120,000 feet and break the sound barrier, you need a really fancy suit.

Austrian skydiver Felix Baumgartner has been working with a company that makes space suits for astronauts in an effort to pull off a record setting jump with the Red Bull Stratos project that he hopes will also lead to safer flight suits for future astronauts.

Baumgartner, the Red Bull star who has done everything from crossing the English Channel during free fall using a carbon fiber wing, to BASE jumping off the tallest buildings in the world, is planning to ascend to the stratosphere in a pressurized capsule carried by a massive helium balloon. Once reaching 120,000 feet, the plan is to depressurize the capsule, open the door and step off.

Retired U.S. Air Force Colonlel Joseph Kittenger steps into the great unknown in1960

Retired U.S. Air Force Colonlel Joseph Kittenger steps into the great unknown in 1960

The current record for a skydive was set way back in 1960 when U.S. Air Force Colonel (Retired) Joseph Kittinger jumped from 102,600 feet. In addition to breaking that record, Baumgartner, like Kittinger, is working with several scientists to research new, safer suit designs for pilots and future space travelers. The hope is to develop the next generation of full pressure suits that would help increase survival if the need to bail out of a spacecraft should ever arise at extremely high altitudes.

The new suit being used by Baumgartner is made by David Clark Inc., the same company that made Kittinger's suit as well as full pressure suits for astronauts and military pilots flying at the edge of the atmosphere in aircraft such as the SR-71 Blackbird, the U-2 and the X-15. The suits provide an artificial atmosphere that allows pilots to survive in what would otherwise be a a deadly environment.

For Baumgartner's jump, temperatures are expected to be colder than minus 58 degrees Fahrenheit, and the air pressure will be so low that a condition known as ebullism would kill him if the pressure suit were to fail. The condition is explained by everybody's favorite formula from chemistry class, the ideal gas law. Ebullism can strike at 19,000 feet, but at 120,000 feet, the outside air pressure is less than one pound per square inch, so vapor bubbles in the blood expand causing the blood to basically boil.

Another potential problem is maneuvering during free fall. In order to achieve Mach 1, Baumgartner will have to adjust his position during free fall and a normal suit is too restrictive to allow sufficient freedom of movement. One of the worries is what would happen if a person were to begin tumbling.

Felix Baumgartner is fitted for his new pressure suit

Felix Baumgartner is fitted for his new pressure suit

Skydivers use their arms and legs to maneuver, but with the limited motion in a space suit, mobility is greatly restricted. The David Clark suit gives Baumgartner more flexibility to move during free fall. So far the Red Bull Stratos team has tested the new suit in wind tunnels, low pressure chambers and several jumps from 25,000 feet. Baumgartner has been fine tuning his "delta" position that he will use to achieve the supersonic jump.

No person has ever broken the sound barrier during free fall, though it is thought if a person were forced to bail out of a spacecraft at altitudes much higher than 120,000 feet, they would achieve supersonic speeds involuntarily. Baumgartner wants to help researchers better understand the possible affects of supersonic speeds on a person falling through the atmosphere as well as the affects on the suit.

Images: Red Bull

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New Evidence of Ice Age Comet Found in Ice Cores

Posted: 30 Mar 2010 02:18 PM PDT


A new study cites spikes of ammonium in Greenland ice cores as evidence for a giant comet impact at the end of the last ice age, and suggests that the collision may have caused a brief, final cold snap before the climate warmed up for good.

sciencenewsIn the April Geology, researchers describe finding chemical similarities in the cores between a layer corresponding to 1908, when a 50,000-metric-ton extraterrestrial object exploded over Tunguska, Siberia, and a deeper stratum dating to 12,900 years ago. They argue that the similarity is evidence that an object weighing as much as 50 billion metric tons triggered the Younger Dryas, a millennium-long cold spell that began just as the ice age was loosing its grip (SN: 6/2/07, p. 339).

Precipitation that fell on Greenland during the winter after Tunguska contains a strong, sharp spike in ammonium ions that can't be explained by other sources such as wildfires sparked by the fiery explosion, says study coauthor Adrian Melott, a physicist of the University of Kansas in Lawrence.

The presence of ammonium suggests that the Tunguska object was most likely a comet, rather than asteroids or meteoroids, Melott says. Any object slung into the Earth's atmosphere from space typically moves fast enough to heat the surrounding air to about 100,000° Celsius, says Melott, so hot the nitrogen in the air splits and links up with oxygen to form nitrates. And indeed, nitrates are found in snow around the Tunguska blast. But ammonium, found along with the nitrates, contains hydrogen that most likely came from an incoming object rich in water — like an icy comet.

More than a century after the impact, scientists are still debating what kind of object blew up over Tunguska in 1908. They also disagree about whether an impact or some other climate event caused the Younger Dryas at the end of the ice age. But the presence of ammonium in Greenland ice cores at both times is accepted.

"There's a remarkable peak of ammonium ions in ice cores from Greenland at the beginning of the Younger Dryas," comments Paul Mayewski, a glaciologist at the University of Maine in Orono who was not involved in the new study. The new findings are "a compelling argument that a major extraterrestrial impact occurred then," he notes.

Whenever a comet strikes Earth's atmosphere, it leaves behind a fingerprint of ammonium, the researchers propose. Immense heat and pressure in the shock wave spark the creation of ammonia, or NH3, from nitrogen in the air and hydrogen in the comet. Some of the ammonium, or NH4+, ions generated during subsequent reactions fall back to Earth in snow and are preserved in ice cores, where they linger as signs of the cataclysmic event.

Although an impact big enough to trigger the Younger Dryas would have generated around a million times more atmospheric ammonia than the Tunguska blast did, the concentrations of ammonium ions in the Greenland ice of that age aren't high enough.

But the relative dearth of ammonium in the ice might simply be a result of how the ice cores were sampled, Melott and his colleagues contend. Samples taken from those ice cores are spaced, on average, about 3.5 years apart, and ammonia could have been cleansed from the atmosphere so quickly that most of the sharp spike might fall between samples.

Image: Aftermath of the Tunguska event.

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Bats Use Sun to Calibrate Geomagnetic Compass

Posted: 30 Mar 2010 11:16 AM PDT


Bats are nocturnal, but some need sunlight to set their internal compass.

"Recent evidence suggests that bats can detect the geomagnetic field," wrote Max Planck Institute ornithologists Richard Holland, Ivailo Borissov and Bjorn Siemers in an article published March 29 in the Proceedings of the National Academy of Sciences. "We demonstrate that homing greater mouse-eared bats calibrate a magnetic compass with sunset cues."

Previously, Holland showed that interfering with the magnetic field around bats impaired their long-distance navigation abilities. Those findings suggested that while bats used echolocation for short-distance steering, they rely on some geomagnetic sense to guide nocturnal flights that take them dozens of miles from home. The details, however, were hazy.

batdirectionsIn the new study, Holland's team captured 32 greater mouse-eared bats. Half of them were placed inside a pair of giant, coiled magnets that created a geomagnetic field misaligned with Earth's, temporarily scrambling their own geomagnetic sense. All were released in an unfamiliar location 15 miles from their home cave.

Bats that were captured at night flew home unerringly, regardless of what the researchers had done. They'd already set their compasses by the sun. But if the bats were captured and magnetically disoriented at twilight, when they would normally be flying around calibrating their compasses, they could no longer find their way home. The bats appear to use the twilight as a point of reference while setting their compasses for the rest of the night.

How the compass works is still a mystery. Some birds use sunset for navigational calibration, but the similarities likely end there. While birds' eyes contain geomagnetically sensitive molecules that are activated by photons, Holland has previously shown that bats don't have this system. Instead, some of their cells appear to be laden with magnetite.

Bats that fly only in the dead of night, such as vampire bats, could provide an interesting comparison, wrote the researchers.

"The cues used by the bats to indicate their position can only be speculated on at this stage," they wrote, noting that ornithologists have argued over the bird compass for decades. "For animals that occupy ecological niches where the sunset is rarely observed, this is a surprising finding."

Images: 1) Greater mouse-eared bat/Gilles San Martin/Flickr. 2) The directions flown by control and experimental control bats when their magnetic fields were disrupted at sunset (above) and after dark/PNAS.

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Citation: "A nocturnal mammal, the greater mouse-eared bat, calibrates a magnetic compass by the sun." By Richard A. Holland, Ivailo Borissov, and Björn M. Siemers. Proceedings of the National Academy of Sciences, Vol. 107 No. 13, March 30, 2010.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.

Phew, It Works! Science Begins at the LHC

Posted: 30 Mar 2010 08:58 AM PDT


Early this morning, two proton beams collided in the Large Hadron Collider's 17-mile-long ring at a combined energy of 7 TeV, three times higher than ever before. Finally, the flood of data particle physicists have been anticipating for years for has begun.

"It's a great day to be a particle physicist," said General Rolf Heuer, director of CERN where the LHC is located, in a press release Tuesday. "A lot of people have waited a long time for this moment, but their patience and dedication isstarting to pay dividends."

Getting the LHC started has not been easy. In September 2008 as it was first turned on, physicists around the world celebrated like never before. Just a week later when the LHC suffered a mechanical failure, it silenced the cheering abruptly like a visiting team hushing the home crowd with a buzzer-beating three-pointer.

Several more setbacks pushed the restart back a full year, and when the machine was turned on again, the celebration was more subdued, and until today, the physics world hadn't fully exhaled. The first page of the first chapter has finally been turned.

"With these record-shatteringcollision energies, the LHC experiments are propelled into a vast regionto explore," said physicist Fabiola Gianotti, spokesperson for the ATLAS experiment on the LHC. "The hunt begins for dark matter, new forces, newdimensions and the Higgs boson."

It remains to be seen how quickly the new machine will begin picking off its prey, however. Catching something as mysterious, elusive and possibly nonexistent as the Higgs boson takes more than just high energy. The beams must be calibrated, and recalibrated and tamed into submission. Scientists must get to know the LHC's typical data output before they can successfully find the anamolies that will be evidence of yet unknown particles and phenomena.

In the meantime, physicists continue to work on the well-oiled, well-understood Tevatron at Fermilab in Batavia, Illinois. The LHC's shadow has been lurking ever closer to the previous world-record holder for the highest energy, but the delayed start and slower ramp-up time put the Tevatron scientists into an unexpected overtime period, and they have continued to work hard chasing results — the Higgs boson in particular.

The LHC will run at its current energy for a year and a half, if all goes well. At this point, physicists expect it will have essentially caught up with the Tevatron, and the race will be over. Regardless of whether it has captured the Higgs boson by then, the Tevatron will be benched indefinitely, and the LHC will take a time out for maintenance and then ramp up to its combined collision energy target of 14 TeV.

Image: CERN

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Tuesday, 30 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Video: Elephants Run Like No Other

Posted: 29 Mar 2010 02:17 PM PDT

A biomechanical analysis of running elephants has revealed that Earth's largest land animals do some strange things at high speed.

Unlike every other quadruped, they use all four legs for braking and propulsion, rather than rather dividing those tasks between hind and front legs.

Elephants also prove to be extremely inefficient while running. Compared to animals like horses, they perform quite poorly. Then again, given their size, running itself is quite an achievement.

"It's pretty cool that they can run at all. And they do it in such a weird way," said John Hutchinson, an evolutionary biologist at the University of London.

thailand2006-mocap-elephant-6In a study published March 29 in the Proceedings of the National Academy of Sciences, Hutchinson's team videotaped six Asian elephants as they ran across mechanical plates that measured the force of each stride. By combining gait models distilled from the video with force measurements, they could quantify the elephants' biomechanics.

Surprisingly, they learned that braking and propulsion is performed equally by each leg. In other quadrupeds, rear legs are mostly used to push off, and front legs to slow down. The elephants' arrangement likely makes them more stable and reduces physical stress placed on each leg, said Huchinson.

Stress reduction could also explain the pronounced knee bend of running elephants. A relatively straight-legged gait, which elephants possess while walking, is better at converting muscular effort into physical force. However, it does little to absorb stresses generated when an elephant's leg hits the ground. Bent knees are a natural shock absorber.

To compensate for the loss of leverage, running elephants must work extra hard. The scientific term for limb leverage is "effective mechanical advantage," or EMA. While walking, elephants have an EMA of one, but it drops to 0.5 in running elephants, calculated Hutchinson.

Even as EMA declines, the force of an elephant's mass striking the ground rises with speed. "If EMA goes down by a factor of two, and the forces that EMA resists go up by a factor of three, muscles have to work six times as hard," said Hutchinson.

That inefficiency could explain why elephants are not known as long-distance runners, and have speeds of just 15 miles per hour. Then again, when you're as big as a small house, there's not much you need to run from.

Video and image: An Asian elephant and trainer in the study; the white patches are infrared reflectors used as reference points in motion models/John Hutchinson.

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Citation: "The extraordinary integration of biomechanical compliance, leverage, and power in elephant limbs." By Lei Ren, Charlotte Miller, Richard Lair, and John Hutchinson. Proceedings of the National Academy of Sciences, Vol. 107 No. 13, March 30, 2010.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.

Bats Get Pitchy to Make 3-D Echolocation Map

Posted: 29 Mar 2010 12:00 PM PDT


Bats can subtly adjust the frequency of the sounds they use to do echolocation to adjust to particularly cluttered terrain.

In a laboratory testing room filled with dangling plastic chains, bats wearing tiny, half-gram microphones were recorded flying through the obstacle course. When confronted with the forest of chains, the bats tended to reduce or increase the sounds they emitted by a few kilohertz. On their return flights, the path is clear and they stop tweaking their frequencies.

The researchers hypothesize that using multiple frequencies helps the bats resolve their environments faster than using single sound could allow.

"It's all a matter of matching the broadcast to the echo," said Mary Bates, a biology graduate student at Brown University and a co-author of the new study March 29 in the Proceedings of the National Academy of Sciences. "It's a matter of ignoring or not processing the things that are going to interfere and doing this careful matching of sound to echo."

The bats need data about the placement of the chains faster than the first round of echoes can provide, so they send out a second and third and a fourth batch. By changing the pitch of the noises slightly, the bats can differentiate between their different noises. Their brains then integrate those streams of sounds into a high-resolution 3-D map of the terrain.

Researchers have often marveled at bats ability to use echolocation even in very crowded environments or among many similar bats using their own sounds to resolve their environments.

"The navy is really interested in what we do because manmade sonar has come nowhere close to what bats and dolphins can do," Bates said.

The frequency-shifting trick is one way that bats are able to echolocate while moving quickly, Bates and her lab leader, Jerry Simmons hypothesize. They also use the trick when dealing with interference from other members of their species, they've discovered.


Images: J. Simmons, J. Barchi, J. Gaudette and J. Knowles.

Citation: "Echolocating bats shift frequencies to avoid broadcast-echo ambiguity in clutter" by ShizukoHiryua, Mary E. Bates, James A. Simmons, and Hiroshi Riquimarouxa. doi: 10.1073/pnas.1000429107

WiSci 2.0: Alexis Madrigal's Twitter, Tumblr, and green tech history research site; Wired Science on Twitter and Facebook.

Monday, 29 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Diagnosing Parasite Infections With Dye and a Blacklight

Posted: 28 Mar 2010 06:01 PM PDT


San Francisco — An inexpensive dye could give some of the world's poorest people an early warning if they are infected with deadly parasites.

The dyereacts with a molecule that is produced by trypanosomes, the microbes that cause leishmaniasis, Chagas disease, and sleeping sickness. If the patient is infected, the chemical turns fluorescent green and glows brightly under a blacklight.

"Early diagnosis is the key to improving treatment of these diseases," said Ellen Beaulieu, a chemist at SRI International who helped to develop the dye, March 21 here at the meeting of the American Chemical Society. "Diagnosis with conventional tests is difficult in developing countries where these diseases occur."

Trypanosomes infect millions of people each year, and sicken great numbers of livestock as well. As far as parasitic diseases go, the death toll from trypanosome infections is second only to malaria.

Many of the medical lab tests that we take for granted require expensive equipment, refrigerated blood samples,high-end microscopes and trained personnel. In the developing world, it's hard to find any of those things.

The newtest could be performed by unskilled personnel anywhere, in just a few minutes, with little more than an ultraviolet flashlight.

Healthcare workers could use strips of paper coated with the dye to diagnose people with all three trypanosomal diseases. To find out if their patient is infected, they would add a reducing agent to a bit of serum and then dunk the test strip into that mixture. If the paper glows with a fluorescent green hue when placed under a blacklight, the person is infected and should get antiparasitic drugs immediately.

Until recently, leishmaniasis was mostly a plague of the developing world, but quite a few soldiers picked up the disease while serving in Iraq, and immigrants have been bringing it to the United States.

"There is a concern that [leshmaniasis] is getting into the blood supply," said Mary Tanga, a medicinal chemist from SRI international. "And soon blood donations will have to be tested for leishmaniasis."

The test is still in an early stage of development and may not be used in the field until 2015, Beaulieu said. It should be put through a rigorous battery of tests to make sure it's sensitive and accurate enough.

Image: Shine a blacklight on the dye alone, and it is almost perfectly clear. Mix it with a peptide that is produced by parasites, and it will turn fluorescent green./Elizabeth Wilson

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Saturday, 27 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

New RFID Tag Could Mean the End of Bar Codes

Posted: 26 Mar 2010 03:11 PM PDT


Lines at the grocery store might become as obsolete as milkmen, if a new tag that seeks to replace bar codes becomes commonplace.

sciencenewsResearchers from Sunchon National University in Suncheon, South Korea, and Rice University in Houston have built a radio frequency identification tag that can be printed directly onto cereal boxes and potato chip bags. The tag uses ink laced with carbon nanotubes to print electronics on paper or plastic that could instantly transmit information about a cart full of groceries.

"You could run your cart by a detector and it tells you instantly what's in the cart," says James M. Tour of Rice University, whose research group invented the ink. "No more lines, you just walk out with your stuff."

RFID tags are already used widely in passports, library books and gadgets that let cars fly through tollbooths without cash. But those tags are made from silicon, which is more expensive than paper and has to be stuck onto the product as a second step.

"It's potentially much cheaper, printing it as part of the package," Tour says.

The new tag, reported in the March issue of IEEE Transactions on Electron Devices, costs about three cents to print, compared to about 50 cents for each silicon-based tag. The team hopes to eventually bring that cost below one cent per tag to make the devices commercially competitive. It can store one bit of information — essentially a 1 or a 0 — in an area about the size of a business card.

That's not much compared to computer chips, but Tour says this tag is just a "proof of concept." Study coauthor Gyoujin Cho of Sunchon National University, along with a team from the Printed Electronics Research Center of the Paru Corporation in Suncheon, Korea, are working to pack more transistors into a smaller area to ultimately squeeze 96 bits onto a 3-square-centimeter tag. That would be enough to give a unique identification code to each item in a supermarket, along with information like how long the item has been on the shelf, Tour says.

The tags were made possible by the creation of semiconducting ink, which contains carbon nanotubes that will hold an electrical charge. A transistor needs to be completely semiconducting to hold information, Tour says. If there are any bits of conducting metal — which moves electric charges around easily — mixed in, the information-holding charge will leak out quickly.

The mixture of nanotubes created in Tour's lab includes both semiconducting nanotubes and conducting nanotubes. Separating out the conducting nanotubes is "a horrid experience," Tour says. "They're very painful to separate." So instead, the team devised a way to coat the conducting nanotubes in a polymer to protect the electric charge and allow the ink to be purely semiconducting.

Once they had the ink, Cho and his colleagues built roll printers to transfer ink to the final material. The tags are printed in three layers, and one of the remaining hurdles to making the tags store more memory in less space is to improve the alignment of those layers, Cho says.

"The work is impressive," comments Thomas N. Jackson of Penn State University in University Park, who is also developing flexible electronics. He thinks it will be difficult to compete with silicon, which is well established in the realm of consumer products packaging. But similar technology could be used to do things silicon can't do, he says, such as make smart bandages that can sense infections or freshness-sensing food packaging.

And for those who would rather not have their food broadcast radio waves after getting it home, fear not. Tour says the signals can be blocked by wrapping groceries in aluminum foil.

What’s It Like to Fly the Space Shuttle? We Find Out

Posted: 26 Mar 2010 12:27 PM PDT


As a person who really enjoys flying airplanes, I never thought I would ever say this, but flying a simulator can be as much fun as flying the real thing. Of course it helps when the simulator is a replica of the space shuttle cockpit at the Johnson Space Center in Houston.

On a recent assignment for AOPA Pilot magazine, I arrived early for an interview with Ken Ham, commander on the shuttle flight scheduled to lift off on May 14. While I waited, an engineer fired up the simulator where we were going to conduct the interview and let me make some practice approaches.

Known as the Shuttle Engineering Simulator, or SES, it's not the full motion simulator used for full flight profile training, but rather a fixed-base simulator used by astronauts and engineers for both training and testing changes that will be made on the shuttle. The SES is very similar to the e-cab used by Boeing and other aircraft makers to test systems before putting them on the real thing.

Whether it was a change to a guidance computer, or an upgrade to the software controlling the nine glass panel displays, many of the improvements made to the shuttle over the years were tested right here. Shuttle commanders and pilots (commander is in left seat, pilot in the right) also use the SES for training, especially early on in their preparation.

The wood on the floor in front of left seat has been worn smooth by thousands of heels sliding back and forth controlling the rudder pedals over the years. With the news that the shuttle will likely continue flying into 2011, instead of being retired later this year as previously scheduled, the SES may yet see a few more heels.

Sadly, even with the extension, this was as close as I would probably get to my astronaut dreams. Still I was eager to try flying the heaviest and most expensive glider ever built.

Primary flight display passing through 33,000 feet

Primary flight display passing through 33,000 feet

Computers control much of the flight until the last 4-5 minutes before landing. So I was given the chance to fly several approaches into the Kennedy Space Center, landing on runway 15. My flights began with the shuttle heading east towards the Atlantic passing over KSC at 50,000 feet and 240 knots (equivalent air speed or KEAS).

It turns out the shuttle is a terrible glider. I don't have a lot of glider experience, but I know that pitching nose down at 20 degrees and a descent rate of around 10,000 feet per minute isn't considered good. An airliner typically follows a 3-degree glide path when approaching the runway. According to Commander Ham, this is probably the biggest challenge facing the average pilot.

"The sight picture is a lot different," he said, "but it's a pretty easy task for an experienced pilot to make a safe landing," Commander Ham said, adding that a perfect landing is very difficult.

Of course, like many things, it might be easy when everything is going right. It's the emergencies and unexpected scenarios that require the bulk of the training.

"Then things get a bit more difficult. It starts to challenge your flying skills a bit more," Commander Ham noted, saying it is similar to flying other aircraft where you train for emergencies. "It's just another flying job."

I paused and debated to myself whether or not to challenge that last point. Never mind.

Back in the sim, I passed through 40,000 feet and got ready to start my turn around the heading alignment cone or HAC, which is a guidance system that allows pilots to follow a circular descent path to the runway. As I continued the turn, I could see the Florida coast out the left window, and out of habit, I started looking for the runway.

The view from left seat inside the SES

The view from left seat inside the SES

My airspeed was around 290 knots as I turned to line up with runway 15 and pass through 12,000 feet. The shuttle is remarkably stable to fly as I suppose would be the case with any brick featuring stubby wings. Moving the stick is a bit unusual because it requires only small wrist movements.

Perhaps most interesting is that it pivots in the middle of the palm for pitch (controlling nose up or nose down). Commander Ham explained later that this is to prevent inadvertent movement during launch. "It's a beautiful design, you can fly uphill at 3g's with your hand on the stick and nothing happens," he said.

So far the approach hadn't been too difficult. In front of me there was a heads-up display (HUD) with airspeed, altitude and other key flight parameters. Most importantly there was a flight-path marker and guidance diamond. These navigation aids make it rather easy for a pilot to find the way to the runway and line up, assuming that everything is working. You just keep the flight-path marker on the guidance diamond and the runway should eventually appear in front of you.

On final approach, a pair of triangles rose from the bottom of the HUD when it was time to begin the flare, which slows the rate of descent. In a typical small airplane, a pilot might begin the flare at 10 to 30 feet above the runway traveling around 60 knots. In the shuttle, you start the flare at 2,000 feet and 300 knots. That part would take some getting used to.

"This is the critical part," Commander Ham explained. "At 2,000 feet, if you don't start pulling up, you're going to die."

So I followed the guidance on the HUD and touched down the main gear with a squeak at 200 knots with the nose still pointing rather high in the air. After what seeemed like a very long time, the nose gear eventually came down with a thud and I rolled safely to a stop.

A space shuttle commander has countless landings in simulators at the Johnson Space Center, and at least a thousand simulated landings in NASA's Shuttle Training Aircraft. I realize I'm a long way from having the skills necessary to fly the orbiter. But if I were ever stowed away in the cargo bay and the announcement came over the speakers, "Is there a pilot on board?" I would at least have a chance of getting the world's heaviest glider on the ground safely.

Images: Jason Paur/

Lab-Quality Booze Detector Fits in a Suitcase

Posted: 26 Mar 2010 11:46 AM PDT


Ever found yourself staring down a punch bowl at a frat party and wondering just how spiked it might be?

What you needed was the AlcoQuick 4000, a briefcase-sized infrared spectrometer that can accurately determine the alcohol content of a wide variety of beverages in just 60 seconds, according to a new study in the open source journal Chemistry Central.

alcoquickFor every day use, you can use an alcoholmeter, first developed by Gay-Lussac in the 1820s. It's essentially a tube that you can insert into a liquid-containing beaker that uses the difference in density between water and alcohol to determine how much alcohol is in the beverage.

But some people, notably scientists and tax collectors, need more precise readings of alcohol content. They use complex techniques that require the liquid in question to be distilled. That limits the diffusion of the techniques and can prove downright impractical in some settings.

The German researchers who conducted the study say that the AlcoQuick could be especially useful in analyzing "unrecorded alcohol," which you might know as "moonshine." They estimate that one-quarter of the world's alcohol consumption comes in this form, largely in developing countries without strong regulatory regimes.

"In this context, expensive laboratory measurements such as distillation and pycnometry are not practical, but portable, battery-powered infrared sensors offer a feasible alternative in areas of lower socioeconomic status," they conclude.

So, watch out Bangladesh, your days of moonshining could be coming to a technology-induced end soon.

Citation: "Rapid and mobile determination of alcoholic strength in wine, beer and spirits using a flow-through infrared sensor" by Dirk W Lachenmeier, Rolf Godelmann, Markus Steiner, Bob Ansay, Jurgen Weigel, and Gunther Krieg. doi:10.1186/1752-153X-4-5

Image: hoggarazzi/Flickr

WiSci 2.0: Alexis Madrigal's Twitter, Tumblr, and green tech history research site; Wired Science on Twitter and Facebook.

Ron Howard Was Wrong: Apollo 13 Would Have Burned, Not Frozen

Posted: 26 Mar 2010 10:33 AM PDT

The Apollo 13 module, had it not been for NASA's heroic efforts to get it back on course, would have missed Earth and tumbled into the depths of cold, lonely space.

At least that's been the story repeated in popular, academic, and cinematic accounts of the ill-fated mission, like Ron Howard's Apollo 13.

Now, space writer Andrew Chaikin and a team of modelers at Analytical Graphics have stumbled upon a surprise: The official story isn't true. Instead of drifting into a nearly eternal orbit around Earth, the ship would have swung out past the moon, been pushed by its gravitational field, and been sent hurtling back toward Earth on a collision path, as described in the video above.

In any case, the crew would not have survived. They'd have frozen first, then burned up on re-entry.

Luckily, James Lovell, Jack Swigert and Fred Haise were able to use the lunar module as a lifeboat and make it safely home with the help of Ed Harris, er, Eugene F. Kranz, the flight director for the mission.

And while we're debunking Apollo 13 myths, the astronauts never actually said, "Houston, we have a problem." They said, "Houston, we've had a problem."

And if you ever correct someone on the presence of that helping verb at a party, you join an elite club of pedants who love space and grammar too much. Contact us immediately with a YouTube video of the incident and we'll send you a pin, because it's our club.


Via CollectSPACE

Image: The damage caused by the oxygen explosion that nearly cost the Apollo 13 astronauts their lives/NASA.

WiSci 2.0: Alexis Madrigal's Twitter, Tumblr, and green tech history research site; Wired Science on Twitter and Facebook.

Friday, 26 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Laser Guidance Adds Power to Wind Turbines

Posted: 25 Mar 2010 11:45 AM PDT


The wind industry may soon be dependent on a different kind of environmental awareness that has more to do with lasers than ecology.

A new laser system that can be mounted on wind turbines allows them to prepare for the wind rushing toward their blades.

The lasers act like sonar for the wind, bouncing off microscopically small particulates and back to a fiber optic detector. That data is fed to an on-board processor that generates a three-dimensional view of the wind speed and direction. Subtle adjustments in the turbine blade's angle to the window allows it to capture more energy and protect itself in case of strong gusts.

The startup company that developed the Vindicator system, Catch the Wind, recently deployed a wind unit on a Nebraska Public Power District turbine. It increased the production of the unit (.pdf) by more than 10 percent, according to the company's white paper. If those numbers held across the nations' 35 gigawatts of installed wind capacity, the LIDAR (Light Detection and Ranging) sensors could add more than 3.5 gigawatts of wind capacity without adding a single additional turbine.

"This is what they call disruptive technology," said William Fetzer, vice president of business development for Catch the Wind. "There are roughly 80,000 to 90,000 wind turbines out in the world, and they don't have this technology."

Wind farms are only as good as their data. There have been revolutions in assessing wind resources over long time-scales, but the short-term gustiness of the wind has remained a problem.

Current wind turbines rely on wind-measuring instruments known as anemometers that are mounted to the back of the turbine's gear-housing unit, called a nacelle. The data from the wind is fed to a computer that optimizes the blades' configuration to capture the most energy from the wind.

In many cases, cup anemometers, which took their current form in the 1930s, are still used. They work well enough, but have to be positioned behind the blades, which subjects them to turbulence. And, importantly, they can only tell you how fast the wind was blowing after it passed. That doesn't help you with a freak gust of wind or any of the odd behavior that renewable energy developers have caught the wind exhibiting.

A young employee of the U.S. Weather Bureau with a cup anemometer in 1943.

A young employee of the U.S. Weather Bureau with a cup anemometer in 1943.

Fort Felker, director of the National Renewable Energy Laboratory's National Wind Technology Center, said he saw great potential in LIDAR and similar sound-wave-based systems generally.

"Once you have a detailed knowledge of the coming wind, there are a lot of opportunities," said Felker told

While he estimates the amount of energy that could be captured is below Catch the Wind's 10 percent, he said the systems could really help reduce the wear-and-tear on machines caused by strong winds hitting improperly positioned blades.

"Researchers have already demonstrated that substantial reduction of loads is certainly possible," Felker said.

LIDAR, despite first being demonstrated for wind measurement in the 1970s, has been slow to catch on. The systems have been too expensive.

"Widespread deployment of the technique has so far been hampered by the expense and complexity of LIDAR systems," (.pdf) a 2005 NREL research report found. "However, the recent development of LIDAR systems based on optical fiber and components from the telecommunications industry promises large improvements in cost, compactness, and reliability so that it becomes viable to consider the deployment of such systems on large wind turbines."

Now, even the most venerable R&D testing group in the world, the Danish National Laboratory for Sustainable Energy's Risøe wind outfit, is working on a turbine-mounted LIDAR system, though they only claim a 5 percent increase in electricity production.

Catch the Wind grew out of a small-business grant that the company's predecessor, Optical Air Data Systems, received from the U.S. military. They developed a LIDAR system for helicopters working in the dusty Iraq and Afghanistan terrain. The company developed their rugged and relatively lightweight LIDAR systems by marrying aerospace knowledge with emerging telecommunications tech like better fiber optic cables and laser diodes.

Still, Catch the Wind may have a tough road ahead. The energy industry is notoriously risk averse. Besides, wind electricity in many places is already cheaper than wholesale electricity prices.

Erin Edholm, a representative for National Wind, a wind-farm developer that's put in more than 4,000 megawatts of turbines, said that the company's wind resource assessment team "has not used [LIDAR] or considered using it to date."

But that doesn't dim the hopes of Catch the Wind's Fetzer for the company's ultimate success.

"When you do disruptive technologies, it takes time," Fetzer said. "People don't believe that things are as bad as they are until they can see what we can do."

It helps that they don't need the wind turbine manufacturers to incorporate their technology to jump start their business. They've got what's known as a "bolt-on" solution, meaning it can be attached to existing turbines. They don't need manufacturers to incorporate their product to sell it to wind farms.

Still, some wind farmers may worry that the warranties they have on their turbines would be voided by adding a LIDAR system. Fetzer said Catch the Wind is working out the warranty issues.

General Electric, which is the largest wind turbine manufacturer in the United States, is not using or developing LIDAR specifically, either. Catch the Wind did recently sell one of their machines to a large, unnamed turbine manufacturer.

Though Catch the Wind is not discussing pricing for their products, Fetzer maintains that their customers will make their money back in the three-to-five year range that he says wind developers are looking for. The 2005 NREL report calculated a preliminary cost for a generic LIDAR system of less than $95,000, once production was up and running.

The development of controls for capturing the most energy from the wind has been a constant theme in wind energy research. But it's not always the company that develops the technology that reaps the rewards from its commercialization. Wind turbines in the 1980s struggled mightily to convert the wind's gusty capriciousness into steady rotary power.

At the time, the turbine's rotor had to turn at a constant rate. Researchers realized that their machines could operate over a larger range of speeds if the rotor could speed up or slow down in response to the wind, but they would need power electronics to translate the power into electricity suitable for the grid.

A multimillion dollar R&D program launched by U.S. Windpower and the Electric Power Research Institute to commercialize a variable-speed rotor resulted in a mostly defective turbine design that helped push U.S. Windpower out of business. The variable-speed rotor went on to become a standard part of wind turbine designs.

Catch the Wind obviously is hoping not to suffer the same fate. They are exploring a variety of business models including sharing the revenue from the extra power they say their systems can generate. If they don't generate any more electricity, the wind turbine owner doesn't pay anything. If they do, Catch the Wind gets half the take.

"It's a good value proposition," Fetzer concluded.

Images: 1. A Vindicator installed in Nebraska/Catch the Wind. 2. American Memory Collection.

WiSci 2.0: Alexis Madrigal's Twitter, Tumblr, and green tech history research site; Wired Science on Twitter and Facebook.

Chemical Fingerprints Could Finger Weapons Makers

Posted: 25 Mar 2010 10:47 AM PDT


SAN FRANCISCO — Finding out whodunit in chemical warfare cases may be aided by scientists focused on the howdunit.

sciencenewsResearchers have developed a technique to ascertain the chemical fingerprint of compounds such as mustard gas, rat poison and nerve agents such as VX. Figuring out the details of how these compounds were created in the first place could provide vital clues to law enforcement agencies aiming to catch chemical warfare criminals and help guide first responders as they gather evidence.

Chemical forensics typically focuses on identifying the compound in question, but chemist Audrey Martin and her colleagues at Lawrence Livermore National Laboratory in California wanted to take these analyses a step further. "If we already know this was a chemical attack using mustard gas, now we want to know who made it," said Martin, who presented the research March 22 in a poster session at a meeting of the American Chemical Society held in San Francisco. "We're looking at the next step — where did this come from?"

The technique relies on the fact that there are often many routes to the same chemical — for example there are 12 different ways of making sulfur mustard gas. Depending on the route and the ingredients, there are various chemical by-products, impurities and unreacted ingredients in the final product. The presence and proportions of these molecules can provide clues to how the compound was made, said Martin. In some cases, such as with the rat poison tetramine, one synthetic route might be ruled out entirely by the presence of a particular ingredient. Signatures of the reaction conditions, such as temperature and pressure, may also be hidden in the final product.

So far, the Lawrence Livermore team has determined these various chemical signatures for a handful of compounds, including Sarin gas and the toxic nerve agent VX. The team is also documenting how these chemicals evolve over time, so scientists can tell if something has been sitting around for five minutes, 20 minutes or a week.

Martin has developed a computer application that she can feed these signatures into, minimizing time spent manually comparing chemical profiles. The researchers are also investigating how such agents interact with food and surfaces such as tile, plastic and metal. This information could help guide first responders charged with sampling a contaminated area, said Martin.

"It's not a smoking gun," she cautions. But if a suspect was seen purchasing a particular ingredient, or has a telltale residue on a shirtsleeve, the method might help clinch a case.

Image: ORNL

As Temperature Rises, Earth Breathes Faster — and Maybe Harder

Posted: 25 Mar 2010 10:18 AM PDT


As planetary temperatures rise, Earth's soils release steadily larger amounts of carbon dioxide, according to massive data crunching from hundreds of soil respiration studies published since 1989.

The critical question is whether soils release more CO2 because faster-growing plants pump more in, or if soils release CO2 that would have stayed in the ground at lower temperatures.

If the latter, the fresh influx of CO2 could produce a self-reinforcing cycle, producing higher temperatures that cause even more CO2 to be released.

"That's the $50,000 question: Is there a feedback effect?" said Ben Bond-Lamberty, a University of Maryland, College Park biogeochemist and co-author of the review, in the March 24 Nature. "The data we have implies a feedback. It doesn't prove it, but it's consistent with the possibility."

Carbon dioxide enters the soil through the roots of living plants and from the decaying bodies of dead plants, and is processed by microbes, fungi and insects. Over time, some of that CO2 releases back into the atmosphere. At any given time, there's about twice as much CO2 in Earth's soils as in its atmosphere.

Because more heat means more energy and faster chemical reactions, Earth scientists have suspected that rising global temperatures would increase the rate of soil respiration. The last review of soil respiration studies (.pdf) took place in 1992, however, and though it found a link between temperature and respiration rates, data was relatively sparse.

In the Nature paper, Bond-Lamberty and fellow UMCP geoscientist Allison Thomson combed the scientific literature for every controlled study of soil respiration published since 1960. They found 439 studies altogether, three-quarters of which were published after the 1992 review. When they analyzed the cumulative data, Bond-Lamberty and Thomson found that soil respiration increased by about 0.1 percent every year since 1989, and was tightly tied to temperature.

"The global soil-respiration flux is changing," said Bond-Lamberty.

soilrespiration1"The results of the analysis are consistent with previous estimations, but are more empirically based," said James Raich, an Iowa State ecologist and co-author of the 1992 review.

The data did contain an anomaly. While respiration tracked with temperature in temperate and tropical regions, there was a negative correlation in the Arctic, where sensitivity to warming is thought to be especially pronounced.

According to Bond-Lamberty, researchers might have a flawed understanding of how carbon cycling works in Arctic soil. Those studies might also have been technically flawed. Because there were many fewer studies conducted in the Arctic than elsewhere, the results may be prone to statistical aberrations.

Whatever the anomaly's explanation, that data was still included when global soil-respiration rates were calculated and the rise identified.

What's not clear from the analysis is whether soil-respiration rates have increased without actually affecting atmospheric balances of CO2, or if CO2 that would have remained earthbound is now being released.

Both possibilities may be true, wrote University of Aberdeen biologist Pete Smith and Fudan University ecologist Changming Fang in a commentary accompanying the analysis.

"Assessing the balance between increased soil carbon inputs through greater plant growth due to climate warming, and increased carbon losses through higher decomposition rates, should be a research priority," they wrote.

A small subset of studies in the review did try to answer that question by experimentally manipulating how much carbon entered test plots of soil. "That dataset is more tentative, but it does imply a feedback," said Bond-Lamberty.

The database used in the study is described in a paper published in February in Biogeosciences. All the data is publicly available.

Images: 1) Nicholas_T/Flickr. 2) Annual global soil respiration, total petagrams/Nature.

See Also:

Citations: "Temperature-associated increases in the global soil respiration record." By Ben Bond-Lamberty & Allison Thomson. Nature, Vol. 464, No. 7288, March 25, 2010.

"A warm response by soils." By Pete Smith and Changming Fang. Nature, Vol. 464, No. 7288, March 25, 2010.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.

Female Chimpanzees Drive the Culture

Posted: 25 Mar 2010 09:32 AM PDT


Chimpanzee culture is driven by its females, suggests a new analysis of six long-term chimp studies.

The number of cultural traits in each colony is linked to the number of females. How many males there are makes no difference.

"Our results suggest that females are the carriers of chimpanzee culture," wrote study co-authors Johan Lind and Patrik Lindenfors, both evolutionary biologists at Stockholm University's Center for the Study of Cultural Evolution.

Lind and Lindenfors' paper, published March 24 in Public Library of Science ONE, was prompted by two sets of observations. First, as becomes more evident with each passing month, chimpanzees possess complex learned behaviors that vary between colony and region. They have culture.

Second, the culture resides in the females. They use tools more frequently than males, and spend more time teaching tricks to their young. And while male chimpanzees tend to stay in the same colony, females will sometimes transfer. Culture would travel with them.

From this, Lind and Lindenfors reasoned that the driving force behind chimpanzee culture ought to be females. They pulled together data from six decades-long studies of chimpanzee colonies in the jungles of Central and West Africa. The data supported their hypothesis.

"The reported number of cultural traits in chimpanzee communities correlates with the number of females in chimpanzee communities, but not with the number of males," they wrote.

chimpculturegraphThat's a different dynamic of cultural transmission than appears to have existed in early humans, where computer models suggest that population density was key. Once there were enough people, cultural evolution accelerated rapidly. After a 2 million-year-long Stone Age, civilization flourished in a comparative handful of millennia.

When trying to understand how chimpanzee culture works, "Some of the general theory behind human cultural evolution cannot strictly be applied to chimpanzees," said Lind. Neither should chimpanzee dynamics be seen as an automatic window into our own past.

"The variation in sociality in now-living apes is phenomenal. We have monogamous gibbons, and then gorillas who live in harems. We have two species of chimpanzees, and their social structures are completely different," said Lind. "According to the best data, we're just as closely related to the bonobo. We could look at them and ask, why don't we have sex rather than kissing on the cheek? There's nothing default about chimpanzees."

An open question is how cumulative chimpanzee culture is, said Lind. Whereas human cultural innovations are "stacked," with innovations building on each other to produce ever-more-complex tools and behaviors, that doesn't seem to be the case with chimpanzees, at least not to a comparable degree way.

Maybe chimpanzees aren't capable of that, or haven't reached their own cultural tipping point, said Lind. Or perhaps we've started to study them too late, with human development having left only isolated pockets of chimpanzee culture.

"When we watch chimpanzees, we look at some scattered remains from previous, much larger populations," said Lind. "I just hope that those remaining spots where chimps can live today will remain."

Images: 1) Mark Fosh/Flickr. 2) Graph of female group size and cultural traits observed in six chimpanzee studies/PLoS ONE

See Also:

Citation: "The Number of Cultural Traits Is Correlated with Female Group Size but Not with Male Group Size in Chimpanzee Communities." By Johan Lind and Patrik Lindenfors. PLoS ONE, Vol. 5 No. 3, March 24, 2010.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.

Thursday, 25 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

DNA Reveals New Hominid Ancestor

Posted: 24 Mar 2010 01:13 PM PDT


A new member of the human evolutionary family has been proposed for the first time based on an ancient genetic sequence, not fossil bones. Even more surprising, this novel and still mysterious hominid, if confirmed, would have lived near Stone Age Neandertals and Homo sapiens.

sciencenews"It was a shock to find DNA from a new type of ancestor that has not been on our radar screens," says geneticist Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. These enigmatic hominids left Africa in a previously unsuspected migration around 1 million years ago, a team led by Pääbo and Max Planck graduate student Johannes Krause reports in a paper published online March 24 in Nature.

The researchers base their claim on DNA from a finger bone belonging to a hominid that lived in the Altai Mountains of central Asia between about 48,000 and 30,000 years ago.

Anthropologists have generally assumed that hominids left Africa in a few discrete waves, starting with Homo erectus about 1.9 million years ago. Neandertal ancestors left between 500,000 and 300,000 years ago, followed by humans around 50,000 years ago.

But the new genetic sequence supports a scenario in which many African hominid lineages trekked to Asia and Europe in the wake of H. erectus, Pääbo suggests.

hominid3This curious sequence was extracted from a piece of finger bone unearthed in 2008 at Denisova Cave in southern Siberia's Altai Mountains. Previous excavations of stone and bone artifacts in the cave indicated that modern humans and Neandertals lived there periodically beginning at least 125,000 years ago. Few fossils have turned up at the site.

While retrieving DNA from presumed Neandertal fossils in November 2009, Krause noticed an unusual mitochondrial sequence. Mitochondrial DNA is located outside the cell nucleus and inherited from the mother.

Krause conducted tests to confirm that the newly recovered mitochondrial DNA came from an ancient hominid rather than from bacteria or researchers who had handled the fossil. Using advanced techniques for fishing DNA fragments out of fossils, the team then assembled a complete mitochondrial genome for the Denisova individual. The same approach has yielded ancient DNA sequences for Neandertals (SN: 3/14/09, p. 5) and a Greenland man who lived 4,000 years ago (SN: 3/13/10, p. 5).

The researchers compared Denisova mitochondrial DNA to complete mitochondrial sequences from 54 people who are living today as well as a human who lived in Siberia about 30,000 years ago, six Neandertals from more than 40,000 years ago, a modern pygmy chimpanzee and a modern common chimp.

Mitochondrial DNA from the Denisova fossil differs from that of humans at almost twice as many chemical positions as Neandertal mitochondrial DNA does, Krause says.

"That number of differences is good evidence for a new hominid because simple variation can't account for it," remarks geneticist Morten Rasmussen of the University of Copenhagen.

Assuming that mitochondrial DNA ancestors of humans and chimps diverged 6 million years ago, the researchers calculate that a mitochondrial ancestor common to the Denisova hominid, Neandertals and modern humans lived between 779,300 and 1,313,500 years ago.

A common mitochondrial DNA ancestor of modern humans and Neandertals lived more recently, an estimated 321,200 to 618,000 years ago.

Krause and Pääbo are now directing an effort to extract nuclear DNA from the Denisova fossil. Comparisons of Denisova, Neandertal and modern human nuclear DNA are needed to confirm that the finger bone comes from a new hominid species and to check for signs of interbreeding with Neandertals or humans.

For now, the researchers refer to the Denisova hominid as "X woman," although its sex remains undetermined until nuclear DNA can be examined.

X woman's finger bone came from a soil layer that has yielded bracelets and other artifacts usually attributed to humans, Krause notes.

"What we can say for now is that there were at least three different forms of hominids living in the Altai Mountains around 40,000 years ago," Pääbo says. At that same time, Homo floresiensis, better known as hobbits, occupied the Indonesian island of Flores (SN: 5/10/08, p. 7). Hobbit DNA has yet to be recovered.

In a comment published with the new report, geneticist Terence Brown of the University of Manchester says that further ancient DNA studies will "possibly increase the crowd of ancestors that early modern humans met when they travelled into Eurasia."

Anthropologist Ian Tattersall of the American Museum of Natural History in New York City agrees. Hominid evolution over the past 6 million to 7 million years includes at least two dozen species, in Tattersall's view. It was "practically routine" for two or more species to live in the same general area at the same time, he says.

Tattersall regards the new mitochondrial DNA sequence as so distinctive that, unless disproved by further evidence, it must represent a new type of hominid.

In contrast, anthropologist Erik Trinkaus of Washington University in St. Louis views the new genetic data skeptically. "I don't know what to make of this, at least not until there is more substantial fossil material than a partial finger bone," he says. "It may be going too far to propose a new hominid."

Trinkaus, who sees fewer species in the hominid family than Tattersall, cautions that biologists have difficulty identifying different species even among living primates. For example, groups of baboons that usually live apart as apparently separate species sometimes aggregate and interbreed, muddying their classification.

Pääbo acknowledges the complexity of finding new hominids in mitochondrial DNA, which in animals such as mice can pass from one species to another via interbreeding. "But there are massive genetic differences between X woman and both Neandertals and modern humans," he says.

Images: Johannes Krause

Chemical From Plastic Water Bottles Found Throughout Oceans

Posted: 24 Mar 2010 10:18 AM PDT


A survey of 200 sites in 20 countries around the world has found that bisphenol A, a synthetic compound that mimics estrogen and is linked to developmental disorders, is ubiquitous in Earth's oceans.

Bisphenol A, or BPA, is found mostly in shatter-proof plastics and epoxy resins. Most people have trace amounts in their bodies, likely absorbed from food containers. Its hormone-mimicking properties make it a potent endocrine system disruptor.

In recent years, scientists have moved from studying BPA's damaging effects in laboratory animals to linking it to heart disease, sterility and altered childhood development in humans. Many questions still remain about dosage effects and the full nature of those links, but in January the U.S. Food and Drug Administration announced that "recent studies provide reason for some concern about the potential effects of BPA on the brain, behavior, and prostate gland of fetuses, infants and children."

The oceanic BPA survey, presented March 23 at an American Chemical Society meeting in San Francisco, was conducted by Nihon University chemists Katsuhiko Saido and Hideto Sato. At an ACS meeting last year, they described how soft plastic in seawater doesn't just float or sink intact, but can break down rapidly, releasing toxins. In their new findings, they showed that BPA-containing hard plastics can break down too, and found BPA in ocean water and sand at concentrations ranging from .01 to .50 parts per million.

As for what those numbers mean for public and environmental health, it's hard to say. BPA can cause reproductive disorders in shellfish and crustaceans, and doses below a single part per trillion can have cell-level effects, but the path from water and sand to ocean animals needs to be studied.

One disturbing possibility is that BPA could bioaccumulate, with animals eating BPA-tainted animals that have eaten BPA-tainted animals, finally reaching high concentrations in top-level ocean predators and the humans who eat them. For that to happen, BPA would have to be stored in fatty tissue, rather than passing quickly through the body.

"That's a really difficult, unsettled question," said Shanna Swan, a University of Rochester environmental medicine specialist who wasn't involved in the survey.

In a 2009 Environmental Health Perspectives study of BPA concentrations in people who had recently fasted, Swan found that BPA levels remained high longer than expected. It's possible that BPA indeed accumulated in their fat, said Swan. They could also have picked up BPA from as-yet-unappreciated non-dietary sources, such as household dust or leaching from PVC water pipes. Or both scenarios may be true.

The BPA contamination found by Saido and Sato likely comes from a mix of boat paint and plastic. About three million tons of BPA-containing plastics are produced each year. The United Nations estimates that the average square mile of ocean contains 46,000 pieces of plastic trash.

"Marine debris plastic in the ocean will certainly constitute a new global ocean contamination for long into the future," wrote Saido and Sato in their presentation.

Image: Polihale/Wikipedia

See Also:

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.