Saturday, 29 January 2011

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Scopes Weeps: Evolution Still Struggling in Public Schools

Posted: 28 Jan 2011 01:44 PM PST

Despite 80 years of court battles ousting creationism from public classrooms, most public high school biology teachers are not strong advocates for evolution.

While vocal advocates of intelligent design and similar non-scientific alternatives to evolution are a minority, more than half the teachers in a nationwide poll avoided taking a strong stance for evolution.

Such teachers "may play a far more important role in hindering scientific literacy in the United States than the smaller number of explicit creationists," wrote Penn State political scientists Michael Berkman and Eric Plutzer, the poll's architects, in a Jan. 28 Science paper.

Berkman and Plutzer, the authors of Evolution, Creationism and the Battle to Control America's Classrooms, examined data from the National Survey of High School Biology Teachers, a representative sample of 926 biology teachers from across the country. They estimate that only 28 percent of those teachers consistently and "unabashedly" introduce evidence that evolution has happened, and build lesson plans with evolution as a unifying theme linking different topics in biology.

At the opposite extreme, 13 percent of teachers explicitly endorse creationism or intelligent design, and spend at least on hour of class time presenting it in a positive light. An additional 5 percent reported that they support creationism in passing or when answering students' questions.


The remaining fraction of teachers, who Berkman and Plutzer dub the "cautious 60 percent," avoids choosing sides. Often these teachers have not taken courses in evolutionary biology and lack confidence in their ability to answer questions from skeptical or hostile students and parents.

There are three popular strategies for evading controversy in the biology classroom, Berkman and Plutzer say. Some teachers focus on evolution at the molecular level, ignoring the idea that whole species of animals can evolve.

Some hide behind rigid state science tests, telling students "it does not matter if they actually 'believe' in evolution, so long as they know it for the test," Berkman and Plutzer wrote.

Others present both sides and let students decide for themselves. This strategy respects high schoolers' critical reasoning skills, but undervalues the scientific method.

"These teachers fail to explain the nature of scientific inquiry, undermine the authority of established experts, and legitimize creationist arguments, even if unintentionally," Berkman and Plutzer wrote.

The researchers offer one major solution: Focus on teacher training. Teachers who have had a course in evolution are statistically far more likely to advocate for evolution in their classrooms. Making such a course mandatory for all incoming teachers could make those teachers more likely to accept and teach evolution.

An evolution requirement could have the spinoff benefit of driving out the avowed creationists, the researchers write.

"Programs directed at preservice teachers can therefore both reduce the number of evolution deniers in the nation's classrooms, [and] increase the number who would gladly accept help in teaching evolution," they wrote. "Combined with continued successes in courtrooms and the halls of state government, this approach offers our best chance of increasing the scientific literacy of future generations."

Image: Clarance Darrow and William Jennings Bryan at the Scopes Monkey Trial. Wikimedia Commons

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That Ain’t No Jackal: New African Wolf Species Identified

Posted: 28 Jan 2011 11:51 AM PST

By Duncan Geere, Wired UK

Conservationists in Egypt have discovered a new species of wolf, which shares DNA with Indian and Himalayan cousins.

The "Egyptian jackal", as it's known, is not in fact a jackal at all, despite the visual similarities it bears to another local species, the golden jackal. The discovery sheds light on how wolf species migrated through Africa and Europe — proving that grey wolves emerged in Africa about 3 million years before they spread to the northern hemisphere.

As long ago as 1880 it had been noticed that the Egyptian jackal looked suspiciously like the grey wolf. Several biologists in the 20th century, studying skulls, made the same claim. Still, the creature retained its name. Now, the difference has been formalised.

The research is reported in the journal PLOS One. Said author David Macdonald in a press release: "A wolf in Africa is not only important conservation news, but raises fascinating biological questions about how the new African wolf evolved and lived alongside the real golden jackals."


Eli Rueness of the University of Oslo, who also contributed to the paper, added: "We could hardly believe our own eyes when we found wolf DNA that did not match anything."

However, the new species' DNA is quite close to wolves found 2,500 kilometres away in the highlands of Ethiopia, which hasn't been widely surveyed.

Professor Claudio Sillero, who's worked in Ethiopia for more than two decades, said in the release: "This discovery contributes to our understanding of the biogeography of Afroalpine fauna, an assemblage of species with African and Eurasian ancestry which evolved in the relative isolation of the highlands of the Horn of Africa. Rare Ethiopian wolves are themselves a recent immigrant to Africa, and split off from the grey wolf complex even earlier than the newly discovered African wolf."

The next step for the team is to work out how many of the wolves exist in the wild. While Golden jackals aren't threatened, it's possible that the "Egyptian jackal" — which is now due for a renaming — is much rarer. Discovering the extent of the population, and where they live, will now be a priority.

Image: Oxford University


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Hidden Fractals Suggest Answer to Ancient Math Problem

Posted: 28 Jan 2011 07:00 AM PST


Researchers have found a fractal pattern underlying everyday math. In the process, they've discovered a way to calculate partition numbers, a challenge that's stymied mathematicians for centuries.

Partition numbers track the different ways an integer can be divvied up. The number 3, for example, has three unique partitions: 3, 2 + 1, and 1 + 1 + 1. Partition numbers grow so fast that mathematicians have a hard time predicting them.

"The number 10 has 42 partitions, but with 100 you have 190,569,292 partitions. They get impossibly huge to add up," said mathematician Ken Ono of Emory University.


Since the 18th century, generations of mathematicians have tried to find a way of predicting large partition numbers. Srinivasa Ramanujan, a self-taught prodigy from a remote Indian village, found a way to approximate partition numbers in 1919. Yet before he could expand on the work, and convert it to a clean equation, he died in 1920 at the age of 32. Mathematicians ever since have puzzled over Ramanujan's manuscripts, which tie the primes 5, 7 and 11 to partition numbers.

Inspired by Ramanujan's work and that of the late mathematician A.O.L. Atkin, Emory mathematicians Amanda Folsom and Zachary Kent joined Ono to discover an infinite, fractal-like pattern to the series. It is described in a paper hosted by the American Institute of Mathematics.

"It was like living in a darkened home for years, and then finally someone turned on the lights. When Zach and I realized the structure, we knew we were right," Ono wrote in an e-mail to "We see the same mathematical structures over and over and over again, similar to how you see repeating elements in the Mandelbrot set as you fly through it. That's why we say they're fractal," he said.

In a separate paper, Ono and Jan Hendrik Bruinier of Germany's Darmstadt Technical University describe a function, deemed "P," that can churn out any integer's partition number.

The combined research doesn't quite reveal a mathematical representation of the universe's structure, Ono said, but it does kill partition numbers as a way to encrypt computer data.

"Nobody's ever going to do that now, since we now know partition numbers aren't random," Ono said. "They're completely predictable and we should no longer pretend they're mysterious."

The discoveries should help solve similar problems in number theory, but Ono said he's most excited about closing an exceptionally "frustrating but romantic" chapter in mathematical history.

Video: Zooming in on the Mandelbrot set, a famous fractal that illustrates repeating patterns in an infinite series./YouTube, eScienceCommons

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Genetic History of Pneumonia-Causing Superbug Unraveled

Posted: 28 Jan 2011 06:45 AM PST

Sometimes natural selection gets a helping hand from humans. A new study tracing the genetic history of a nasty strain of pneumonia-causing bacteria shows that antibiotics and vaccines helped shape the microbe's evolution.

In a technical tour de force, an international team of researchers deciphered the complete genetic blueprints of 240 samples of a strain of Streptococcus pneumoniae taken from sick people in 22 countries. The samples were isolated between 1984 and 2008, allowing researchers to see how the bacteria changed over time.

This strain of pneumonia, known as the Pneumococcal Molecular Epidemiology Network clone 1 or PMEN1, was first recognized in a hospital in Barcelona in 1984. But the new analysis indicates the strain probably first arose about 1970, the team reports in the Jan. 28 Science.

"When this clone emerged, it emerged into a world in which penicillin was frequently used," says study coauthor Stephen Bentley, a molecular microbiologist at the Wellcome Trust Sanger Institute in Hinxton, England. Because the strain was not killed by penicillin, it had an advantage over strains that were susceptible and quickly spread.


S. pneumoniae is a common cause of death, especially among young children. A recent estimate published in the Lancet, for example, showed the bacteria caused 14.5 million cases of serious disease in children aged 1 to 5 worldwide in 2000, killing about 826,000. The PMEN1 strain contributes to these totals and, because of its resistance to several different antibiotics, has become a public health concern. The strain is considered a major cause of pneumonia, meningitis and other infections worldwide. The new study reveals some of the genetic tricks the organism used to develop drug resistance.

Since its emergence, the strain has changed one of its DNA letters about every 15 weeks, the analysis reveals. That rate of mutation is rapid but similar to rates seen in the deadly antibiotic-resistant Staphylococcus aureus bacteria commonly called MRSA.

The strain also occasionally swaps or recombines DNA with other bacteria, and such recombination may be far more important in developing drug resistance. Each DNA-swapping episode brings about 72 single-letter changes on average and sometimes introduces entirely new genes, or new versions of genes.

"Although it's already got a winning formula for spreading around the globe, it's constantly rearranging its DNA," says Bentley.

One way the bacterium evades the body's immune system is by wrappingitself in a sugar coating called a polysaccharide capsule. The PMEN1 strain's capsule is designated serotype 23F to distinguish it from other capsules that use slightly different sugars. The capsule is also one target of a vaccine called PCV7, first introduced in 2000.

But the new analysis shows the pneumonia bacteria were already ahead of vaccine makers. By the time the vaccine hit clinics, a small number of pneumonia bacteria had already swapped DNA with other bacteria and changed their sugar coats to serotype 19A. That switch probably happened in the United States around 1996 and independently in Spain in 1998. When the vaccine was introduced, it drastically reduced the number of infections with bacteria coated in the 23F capsule, leaving the field clear for 19A infections to take over. Newer versions of the vaccine target more types of capsules.

The study "illustrates that these genes are under enormous selection pressure due to human interference with antibiotics and vaccines," says Garth Ehrlich, a bacterial pathologist at the Allegheny-Singer Research Institute in Pittsburgh. Mapping the organism's past genetic contortions may not help researchers predict what the bacteria will do next, but the analysis shows that some genes are particularly prone to changes and probably are not good vaccine targets, he says.

Image: Scanning Electron Micrograph of Streptococcus pneumoniae./CDC/ Dr. Richard Facklam

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Seahorse Shape Explained as Stealth-Attack Adaptation

Posted: 28 Jan 2011 04:00 AM PST

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According to a new explanation of seahorse shape, those distinctive S-curve bodies let them reach further than straight-bodied ancestors.

Compared to tube-shaped pipefish, their closest relatives, seahorses extend their snouts an extra 30 percent. The difference is only a few millimeters, but for animals with a strike range of a centimeter or two, it's a big advantage.

"This makes them stealthier and sneakier hunters," said Lara Ferry, an Arizona State University ecomorphologist who co-authored the study, published Jan. 25 in Nature Communications. "Their prey is less likely to spot them coming, and they are less likely to miss a meal."

To test the link between shape and hunting ability, Ferry's team created a computer model predicting the movements of seahorses and pipefish. By tweaking the features of the model fish, they could estimate how body curvature affected range. They verified their results with high-speed video of seahorses and pipefish feeding.

The videos were needed, Ferry said, because the naked eye can't see seahorses feed. They're among the fastest eaters known.

"From the time they spot prey and open their mouth, to the time the shrimp is completely devoured, is only four milliseconds," said Ferry.

Seahorses rely on stealth attack because they're poor swimmers. While most fish, pipefish included, swim towards their prey, seahorses hide in sea grasses or corals, hang on with a prehensile tail, and wait for tiny shrimp to float by. To prepare for a strike, they tense their muscles and — like a stretched sling-shot — snap forward. (Watch video from Nature's website.)

Seahorses are also unusual for being monogamous, and are among the only species in which males bear young.

All images: Randy Wilder/Monterey Bay Aquarium.
The aquarium is now hosting a special exhibition,
The Secret Lives of Seahorses.

Deep-Sea BP Spill Dispersants Didn’t Degrade for Months

Posted: 27 Jan 2011 01:49 PM PST

Nearly 3 million liters [771,000 gallons] of a chemical dispersant ejected into oil and gas from BP's Deepwater Horizon oil spill last spring and summer lingered until at least September, a new study shows. The chemicals moved in concert with plumes of oil deep beneath the Gulf of Mexico's surface.

David Valentine of the University of California, Santa Barbara and his colleagues periodically sampled plume water that flowed at depths of 1,000 meters or more between May and September 2010. They shipped these samples to chemist Elizabeth Kujawinski at the Woods Hole Oceanographic Institution in Massachusetts and her colleagues for analysis.

With rare exception, they report online Jan. 26 in Environmental Science & Technology, the dispersant did not degrade but instead moved with the plumes until they were lost to dilution in the Gulf's depths.

"If the dispersant worked, it should have been associated with the liquid oil — that is, moving off laterally into the deep-water plume. Which is where we found it — and the only place," Kujawinski says. "We did not see it below the plume or even sloughing off the top of it."


To scout for the dispersant, known as Corexit 9500A, Kujawinski focused on an active ingredient known as DOSS, or dioctyl sodium sulfosuccinate. It accounted for 10 percent by weight of the dispersant mixture, which was released at rates ranging from around 13,000 to 80,000 liters [3,400 to 21,000 gallons] per day.

Prior to capping the well, plume concentrations of DOSS hovered in the low-parts-per-million range, after which it diminished to parts-per-billion concentrations. DOSS levels in the plume matched what would have been expected if the dispersants remained with the oil. That, Kujawinski says, suggests no biodegradation of DOSS — and shows why remnants of dispersant applications could be detected 300 kilometers [186 miles] from the wellhead and even two months after their last application.

"When you read about Corexit, it's supposed to biodegrade," observes Carys Mitchelmore of the University of Maryland's Center for Environmental Science in Solomons. But specific rates have not generally been reported, she adds. So the dispersant's apparent persistence in the new paper is somewhat unexpected.

Then again, Mitchelmore notes, "Corexit is made up of multiple chemicals, so each might have different biodegradation rates." The aquatic toxicologist says she would like to see are data showing whether Corexit enhanced the ultimate breakdown of BP's oil.

"The jury's still out on the role of dispersants in oil degradation," she says. "Some say they enhance it, others say they inhibit it."

Like Mitchelmore, Beth McGee of the Chesapeake Bay Foundation in Annapolis, Maryland., served on a 2005 National Academy of Sciences assessment of oil-spill dispersants. Clearly, McGee says, undersea use in the Deepwater Horizon spill constitutes "uncharted territory."

"Dispersants typically degrade fairly rapidly," McGee says. "So the new data leave me fairly surprised." And, she adds, the results suggest that novel uses — such as injecting them a mile below the surface where it's cold and there's no light — deserve study, if only to answer questions prompted by the BP spill.

Image: DigitalGlobe-Imagery/Flickr

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In the Blink of Bird’s Eye, a Model for Quantum Navigation

Posted: 27 Jan 2011 01:20 PM PST

European robins may maintain quantum entanglement in their eyes a full 20 microseconds longer than the best laboratory systems, say physicists investigating how birds may use quantum effects to "see" Earth's magnetic field.

Quantum entanglement is a state where electrons are spatially separated, but able to affect one another. It's been proposed that birds' eyes contain entanglement-based compasses.

Conclusive proof doesn't yet exist, but multiple lines of evidence suggest it. Findings like this one underscore just how sophisticated those compasses may be.

"How can a living system have evolved to protect a quantum state as well — no, better — than we can do in the lab with these exotic molecules?" asked quantum physicist Simon Benjamin of Oxford University and the National University of Singapore, a co-author of the new study. "That really is an amazing thing."

Many animals — including not only birds, but some mammals, fish, reptiles, even crustaceans and insects — navigate by sensing the direction of Earth's magnetic field. Physicist Klaus Schulten of the University of Illinois at Urbana-Champaign proposed in the late 1970s that bird navigation relied on some geomagnetically sensitive, as-yet-unknown biochemical reaction taking place in their eyes.

Research since then has revealed the existence of special optical cells containing a protein called cryptochrome. When a photon enters the eye, it hits cryptochrome, giving a boost of energy to electrons that exist in a state of quantum entanglement.

One of the electrons migrates a few nanometers away, where it feels a slightly different magnetic field than its partner. Depending on how the magnetic field alters the electron's spin, different chemical reactions are produced. In theory, the products of many such reactions across a bird's eye could create a picture of Earth's magnetic field as a varying pattern of light and dark.


'N@C60 is quite a sexy, interesting, promising molecule.'

However, these quantum states are notoriously fragile. Even in laboratory systems, atoms are cooled to near–absolute-zero temperatures to maintain entanglement for more than a few thousandths of a second. Biological systems would seem too warm and too wet to hold quantum states for long, yet that's exactly what they appear to do.

Researchers led by University of California, Irvine physicist Thorsten Ritz (.pdf) showed in 2004 that, although robins had no trouble pointing their beaks toward Africa under the influence of Earth's magnetic field alone, adding a second, shifting field destroyed their inner compasses. That second field was so weak — less than one-third of 1 percent of Earth's field — that it could only have influenced a quantum-sensitive system.

"It shouldn't be the case that the birds would even know that this had happened," Benjamin said. "If someone changed the brightness of the scene that you're seeing by a-third of 1 percent, you would struggle to know that it even happened. It certainly wouldn't muck up your vision.

In a new paper in Physical Review Letters, Benjamin and colleagues built a mathematical model of Ritz's experiment, including the Earth's magnetic field, the slight secondary field, and the quantum systems that might make up the birds' magnetic sense.

They calculated that, in order to be sensitive to such weak fields, entangled states in the birds' eyes must last for at least 100 microseconds, or 0.0001 seconds.

To put this in perspective, Benjamin introduced an exotic molecule called N@C60, a geometric cage of carbon with a nitrogen atom inside. This molecule is one of the best-known laboratory systems for maintaining entanglement. "The cage acts to shield the atom, which is storing the information, from the rest of the world," Benjamin said. "It's considered to be quite a sexy, interesting, promising molecule."

But at room temperature, even N@C60 only holds entanglement for 80 microseconds, or four-fifths of what birds appear to be doing.

"I think this is a very nice paper that attacks the problem from an interesting angle," said Schulten, who was not involved in the work. "They use a hugely simplified model, but they make an interesting point. Entanglement could stay protected for tens of microseconds longer than we thought before."

"The bird, however it works, whatever it's got in there, it's somehow doing better than our specially designed, very beautiful molecule," Benjamin said. "That's just staggering."

Images: 1) The European robin. Courtesy Ernst Vikne/Flickr. 2) Schematic drawing of N@C60. Courtesy Simon Benjamin.

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Ancient Tools May Mark Earlier Path Out of Africa

Posted: 27 Jan 2011 11:00 AM PST

The bodies are still missing, but a prehistoric toolkit discovered in the United Arab Emirates has led some archaeologists to propose a more complex scenario for humanity's emigration out of Africa.

Uncovered at a Jebel Faya rock shelter, just west of the Straits of Hormuz at the mouth of the Persian Gulf, the tools are 125,000 years old. Previous estimates placed the dispersal of modern humans from North Africa around 70,000 years ago. If correct, this new study indicates that humans in eastern Africa left earlier, and traveled to Arabia.

The tools include small hand axes, scrapers and notched tools called denticulates. They're described Jan. 27 in Science. According to researchers led by University of London paleogeographer Simon Armitage, the tools resemble those made in the same era by humans in eastern Africa, rather than tools found at later sites along the Mediterranean's eastern border.

On the basis of these tools, Armitage and co-authors propose that humans crossed from eastern Africa to Arabia around 130,000 years ago. Lower sea levels may have opened a path, and increased rainfall would have made the Jebel Faya area less arid than it is today.

From southeast Arabia, humans "would have reached South Asia much earlier than assumed and would have had more time to adapt to all kinds of environments encountered in the whole of Eurasia," wrote study co-author and University of Tübingen archaeologist Hans-Peter Uerpmann.


The findings support a scenario suggested by University of Birmingham archaeologist Jeffrey Rose in December 2010 in Current Anthropology. He described how a "Gulf Oasis" could have sheltered humans 100,000 years ago, and even earlier.

Skeletons would provide an important test of the toolmakers' proposed identity. When asked if any remains had been found, however, Uerpmann said, "No bones at all. The earliest bone-finds of 'moderns' are from Qafzeh and Skhul in Israel."

At about the same age as the Jebel Faya tools, these controversial fossils may represent the oldest anatomically modern humans outside of Africa, although a recent American Journal of Physical Anthropology paper made a poorly substantiated claim of 400,000-year-old humans in Israel's Qesem Cave.

The new study "provides important clues that early modern humans might have dispersed from Africa across Arabia, as far as the Straits of Hormuz, by 120,000 years ago," said Chris Stringer, an anthropologist at London's Natural History Museum and "Out of Africa" scholar.

Given the disparity between the Jebel Faya tools and those found at Skhul and Qafzeh caves in Israel, however, Stringer wonders if separate populations may have taken different paths out of Africa.

"Could there have been separate dispersals," he asks, "one from East Africa into Arabia, and another from North Africa into the Levant?"

Images: Science

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10 Critical Endangered-Species Battles

Posted: 27 Jan 2011 09:03 AM PST

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In theory, decisions about flora and fauna habitat are purely scientific. In practice, they're political. And that, in a nutshell, is the reality of the Endangered Species Act, passed in 1973 as part of a historic wave of legislation that both protects America's environmental heritage and provides a framework for settling conflicts.

Some say it does too little; others, that it intrudes too much. The arguments go 'round and 'round, and underscore a fundamental truth: In the Anthropocene Era, people decide nature's fate.


Mexican Spotted Owl

The Mexican spotted owl is less iconic than its northern counterpart, which two decades ago touched off a bitter conservation battle over the Pacific Northwest's old-growth forests. But even as it's flown under the radar, the Mexican spotted owl's fate may prove crucial to the future of wildlife in the United States.

The owl is at the center of Arizona Cattle Growers' Association v. Salazar, one of two endangered-species cases now under possible consideration by the Supreme Court. If the court chooses to hear the linked cases, its decision may guide how the U.S. Fish and Wildlife Service — the federal agency tasked with carrying out the Endangered Species Act — evaluates economic impacts when designating crucial habitat for rare animals.

Photo: National Park Service

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Princess Leia Debuts Kinect-Powered 3-D Video Streaming

Posted: 27 Jan 2011 06:44 AM PST

The Force is strong with holographic scientists these days. Researchers from MIT unveiled the fastest 3-D holographic video to date at a conference in San Francisco January 23, filming a graduate student dressed as Princess Leia and projecting her as a postcard-sized hologram in real time.

The holographic device plays a 3-inch projection at 15 frames per second, just shy of movie refresh rates of 24 to 30 frames per second, the MIT researchers demonstrated at the Society of Photo-Optical Instrumentation Engineers' conference on practical holography.

The red hologram is jerkier and has much lower resolution than the one in Star Wars that sparked the public fascination with 3-D holograms in the 1970s. In fact, it kind of looks like a red blob on a staticky TV. But it's 30 times faster than a telepresence device created in 2010 by University of Arizona researchers (SN Online: 12/4/10).

"I think it's an important milestone because they were able to get to 15 frames per second, which is almost real time," says physicist Nasser Peyghambarian, who led the Arizona research. "The quality is not as high, but hopefully it will get better in the future."


The key to speed was computational power. The MIT team used a Kinect camera from an Xbox 360 gaming console to capture light from a moving object. Then they relayed the data over the Internet to a PC with three graphics processing units, or GPUs, tiny processors found in computers, cell phones, and video games that render video quickly. The processors compute how light waves interfere with each other to form patterns of light and dark fringes. Light bouncing off these fringe patterns reconstructs the original image. The MIT team used a display to illuminate the computer-generated fringes and create a hologram.

"The students were able to figure out how to generate holograms by using what GPU chips are good at," says Michael Bove, an MIT engineer who led the research. "And they get faster every year. There's room for a lot more understanding of how to compute holograms on them."

MIT's holograms are fast, says Peyghambarian, but they have to trade quality for speed.

Bove's device uses one camera that estimates the depth of the object it is filming. The disadvantage of one camera, which is more consumer-friendly, is that you can't see behind objects, says Bove. Also, even though graphics cards can compute high-resolution holograms, the effective display size is limited by a chip in the physical display to 150 millimeters by 75 millimeters, which Bove says is the biggest challenge to creating better holograms.

The Arizona device had a very different setup: Researchers grabbed video from 16 cameras angled around the object, so that one could walk around a holographic person and see not just the front side, but side profiles and back views. The team used an old-fashioned method that hologram artists have employed for decades, employing two lasers to create fringe patterns. Their key insight was engineering a special type of plastic that erases and rewrites quickly. The Arizona hologram is already high-definition and the size of a 17-inch TV, but speeding it up will require switching to a new laser system, says Peyghambarian.

"There's a variety of technologies," says Bove. "The fact is, the barrier to entry has been unbelievably high for the past 20 years. Now, many technologies are maturing at the same time. I think we'll see some fun things in the next few years."

Bove looks to the near future for consumer teleconferencing that connects people far, far away from each other, just like Darth Vader and the Emperor in their imperial chats. Star Wars purists will remember that Princess Leia's plea was actually prerecorded.

Video: YouTube/MITNewsOffice

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Thursday, 27 January 2011

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Hubble Finds Galaxy Beyond Key Benchmark

Posted: 26 Jan 2011 12:23 PM PST

A candidate for the most-distant galaxy ever spotted has shown up in an image from the Hubble Space Telescope. The faint fuzzy blob, whose light reached Hubble from just 480 million years after the Big Bang, could be a landmark in galaxy detection.

"It's amazing that we finally believe that we have observed something at this epoch," said astronomer Rychard Bowens, now of Leiden University in the Netherlands, lead author of a paper to appear in the Jan. 27 Nature. "It's like breaking the 4-minute mile in running. It's had a little bit of awe."

The new galaxy, called UDFj-39546284, is about 13.2 billion light-years away. The last record holder was confirmed in October 2010 at 13.1 billion light-years away. Both galaxies were spotted in a Hubble image called the Ultra Deep Field, which captures 10,000 galaxies in the universe's earliest millennia.

Although the new galaxy is not, in astronomical terms, much farther away than the next-most-distant galaxy, it may be the first to hit "redshift 10," a distance milestone that astronomers have been aiming at for decades.

The term comes from the technique used by astronomers to estimate the distance from Earth of faraway cosmic objects. Because the universe is expanding, distant stars and galaxies appear to be zooming away from us. As galaxies recede, the wavelength of their emitted light stretches out, making them appear more and more red.

Measuring a galaxy's redshift tells how long ago its light was emitted. Multiply time by the speed of light, and distance can be calculated.

"Redshift 10 has been this gauntlet, this quest. A lot of people have attempted to get there," Bouwens said. "I think this is the first time that it's actually plausibly at this epoch."


This galaxy is dimmer than the previous oldest galaxy, in keeping with a pattern: As astronomers look back through time, galaxies are fainter. They have fewer young stars, which burn especially bright.

Run from the beginning, though, and they're getting brighter. The Ultra Deep Field image seems have caught the universe in a growth spurt.

"Galaxies are like human beings," growing fastest when they're young, Bouwens said.

To make the Ultra Deep Field image, Hubble used the new Wide Field Planetary Camera 3, part of a 2009 upgrade, to stare for 87 hours at a patch of sky roughly equivalent to what's covered by a postage stamp, folded into quarters and held at arm's length.

"We wouldn't even be able to come close without this instrument," Bouwens said.

Unfortunately, this galaxy runs right up against Hubble's detection limit. If the galaxy were farther away, it would be too red for Hubble to see at all.

"Our object is about as good as it's going to get for some time," Bouwens said. "It'll be hard to find more-compelling evidence for a distant object than what we've done."

Despite Bouwen's confidence, some astronomers are still skeptical.

"It was selected using a very rough technique, and it's plausible that it's at redshift 10, but it could be at lower redshift," said astronomer Naveen Reddy of the National Optical Astronomy Observatory in Arizona, who was not involved in the new work. "More work needs to be done."

Bouwens and his colleagues admit that they can't be 100 percent certain that their galaxy is actually at redshift 10, or that it's really there at all.

"There's been a grand tradition of people crying wolf about redshift-10 galaxies," said Bouwens. "There's some worry that it could just be noise. That would be really embarrassing."

To find galaxies at distances beyond redshift 10, astronomers will have to wait for the James Webb Space Telescope, the proposed successor to Hubble. In theory, the Webb could see out to redshift 35 — if there's anything there to see.

The very early universe was a hot soup of neutral hydrogen atoms. Hydrogen absorbs light at most wavelengths, so this era of the universe should be an opaque fog.

But high-energy radiation from the first stars stripped the hydrogen atoms of their electrons, turning the universe transparent in an epoch astronomers call reionization.

Observations of galaxies like UDFj-39546284 suggest that the stars we can see wouldn't be powerful enough to turn the universe transparent. There must be smaller, fainter galaxies hiding in the data.

Images: NASA, ESA, Garth Illingworth (University of California Santa Cruz) and Rychard Bouwens (University of California Santa Cruz and Leiden University) and the HUDF09 Team.

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Carnivorous Plants Eat Poop From Tiny Bats

Posted: 26 Jan 2011 07:37 AM PST

By Mark Brown, Wired UK

In a bizarre example of a symbiotic relationship, tiny bats in Borneo have been found using a carnivorous plant as a toilet, feeding the pitcher plant with their droppings, while they safely roost in the plant's traps.

Ulmar Grafe, an associate professor at the Universiti Brunei Darussalam, was researching the pitcher plant — a giant, carnivorous vine with deep, pitfall cups that are used to trap prey — for a study published in Biology Letters. Grafe wanted to find out how the pitcher managed to find the nitrogen needed to survive in the nutrient-poor peat swamps of Borneo in southeast Asia.

His team found Hardwicke's woolly bat — a tiny, four gram animal no bigger than a car key — consistently sleeping in the carnivorous plant's traps during the day. Sometimes alone, sometimes with a partner or with a child. Roosting on top of each other, two or three bats could snugly fit in the pitchers.


But the plant wasn't getting its nutrients by munching on the tiny bats. In fact, the plant has adapted to stop the winged critters from tumbling down into the bottom of the trap and drowning in the digestive fluid. The vine's pitchers have a tapered shape and an unusually low amount of fluid, to stop the bats accidentally becoming dinner. That also prevents the monkeys from eating the insects that the plant catches.

Instead, the plants get their nutrients from the bat droppings, absorbing the feces and urine for nitrogen.

It's only the second time that researchers have documented a case of a mammal using a carnivorous plant as a natural toilet. In 2009, researchers found tree shrews defecating into another type of plant. But the shrews didn't seem to use the plant in return, exhibiting a nonchalant poop-and-go attitude.

The bats, however, have a mutualistic link with the plant, choosing its cozy, dry cavity and lack of blood-sucking ectoparasites as a perfect place to roost.

Image: Ulmar Grafe

Source: Wired UK

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First Earth-Orbiting Solar Sail Unexpectedly Unfurls

Posted: 26 Jan 2011 04:00 AM PST

After a month and a half trapped in its mothership, NASA's NanoSail-D spacecraft has finally unfurled the first solar sail to circle the Earth.

Solar sails, gossamer-thin sheets that feel the pressure of the solar wind, have been suggested as a best hope for propelling spacecraft between the stars. They're the only known method of space travel that doesn't require carrying heavy fuel on the journey.

But solar sails have had a checkered history. Only one has ever actually worked: the Japanese IKAROS spacecraft, which launched in 2009 and flew by Venus in 2010.

NanoSail-D looked set to be another heartbreak. It launched aboard the Fastsat (Fast, Affordable Science and Technology SATellite) in November 2010, along with five other experiments. A spring was supposed to push the breadbox-sized NanoSail-D probe into its own orbit. But when the time came, the probe got stuck.


To everyone's surprise, NanoSail-D spontaneously ejected itself on Jan. 17. Engineers still don't entirely know why.

Three days later, on Jan. 20 at 10 p.m. EST, the free-flying spacecraft unfurled its silvery sail. An onboard timer activated a wire burner, which cut a 50-pound fishing line holding the spacecraft's panels closed. Within seconds, the thin polymer sheet unrolled into a sail 10 square meters in area.

"This is tremendous news and the first time NASA has deployed a solar sail in low-Earth orbit," said NASA engineer Dean Alhorn in a press release. "To get to this point is an incredible accomplishment for our small team."

The successful unfurling was confirmed from the ground with the help of amateur ham radio enthusiasts, who continue to track NanoSail-D.

Rather than soar between the stars, NanoSail-D was designed to help clean up space junk. As the sail orbits, it skims the top of the atmosphere, experiencing enough drag to pull the sail back to Earth in 70 to 120 days.

If it works to clean up the clutter in low-Earth orbit, drag sails might become a standard issue on future satellites, pulling them out of the sky to disintegrate harmlessly in the atmosphere.

Skywatchers should be able to track and photograph NanoSail-D before it returns to Earth. Stay tuned for details.

Via Science@NASA

Image: NASA

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