Tuesday, 2 March 2010

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Millions of Tons of Water Ice Found at Moon’s North Pole

Posted: 01 Mar 2010 05:24 PM PST


A moon probe has found millions of tons of water on the moon's north pole, NASA reported Monday. The vast source of water could one day be used to generate oxygen or sustain a moon base.

A NASA radar aboard India's Chandrayaan-I lunar orbiter found 40 craters, ranging in size from 1 to 9 miles across, with pockets of ice. Scientists estimate at least 600 million tons of ice could be entombed in these craters.

The radar, called the Mini-SAR, sends pulses of left-polarized radio waves out to measure the surface roughness of the moon. While smooth surfaces send back a reversed, right-polarized wave, rough areas return left-polarized waves.

Ice, which is transparent to radio waves, also sends back left-polarized waves. The Mini-SAR measures the ratio of left to right circular polarized power sent back, or the circular polarized ratio (CPR). However, a high CPR alone can't distinguish between rough patches and regions with ice.

The north pole craters had a high CPR on the inside, with a low CPR on the edges. That suggests a material enclosed in the craters, rather than surface roughness, caused the high CPR signal. According to NASA, the ice would have to be relatively pure ice and at least several feet thick to give this signature.

In November, NASA crashed a probe into the Cabeus crater near the moon's south pole and also found evidence of water.


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67 Million-Year-Old Snake Fossil Found Eating Baby Dinosaurs

Posted: 01 Mar 2010 05:00 PM PST

Indian snake - 17

Scientists have found a 67 million-year-old fossil of a snake coiled around dinosaur eggs and a hatchling. This is the first evidence of snakes eating dinosaurs.

"It's a stunning, once-in-a-lifetime find," said paleontologist Paul Sereno of the University of Chicago, who was not involved in the study. "We've caught one of the rarest moments in the fossil record, which is prey and predator, together."

Geologist Dhanajay Mohabey of the Indian Geological Survey first unearthed the fossil 26 years ago in a rocky, limestone outcropping in the northwestern Indian village of Dholi Dungri. He thought all the bones at the site were those of dinosaur hatchlings.

But in 2001, University of Michigan paleontologist Jeff Wilson, took a second look at the fossils. The team then recognized they had actually found a snake coiled around a broken egg, with a hatchling and two other eggs nearby. The findings appeared Mar. 1 in Public Library of Science Biology.

Indian snake - 15

The newly discovered species of snake, Sanajeh indicus, measures about 11.5 feet long. The hatchlings, part of a group called titanosaurs, measured about a foot and a half long. Titanosaurs were the largest animal to ever walk on land, with adults that could reach up to 100 feet long.

Unlike modern snakes, S. indicus lacked jaw joints that allowed it to open its mouth incredibly wide, so it relied on its large overall body size to prey on the fledgling dinosaurs. Luckily for the snake, the titanosaur hatchlings had soft skeletons that "may have been somewhat collapsible, so you can fold their ribs up a bit and get them in your mouth," Wilson said.

It's likely a slow-rising flood or a storm caused adult titanosaurs to flee, abandoning their nests. The snake then slithered into the nest.

Once the babies start hatching, they begin to "pop their leg or arm out. There will be some kind of activity, and the snake is attracted to that. It will coil itself around the egg," he said. "As soon as it came out of the egg, there's a snake waiting for it."

Indian snake - 16

Unluckily for the snake, that moment was frozen in time because a landslide buried the site right then, Wilson said.

The team has found three or four other spots at Dholi Dungri where snake fossils were uncovered near dinosaur eggs, Wilson said.

The findings may offer insight into the origin of snakes. The reptiles first appear in the fossil record around 98 million years ago, Wilson said. But finding such a complete snake fossil is rare, with only a half-dozen well-preserved specimen from this period. "A lot of their early origins are uncertain. More fossils from an early time help put together a picture of snake evolution," said Wilson.

The fossil find shows some modern animal behavior has very old roots, Sereno said. "Snakes have been at this eating egg-thing for a hundred million years. Before birds fell prey to these things, their ancestors did."

Images: 1) Reconstruction of scene, Sculpture by Tyler Keillor and original photography by Ximena Erickson (image modified by Bonnie Miljour). 2) Fossil from the site, Wilson et al. 2010, PLoS Biology 3. Schematic, Wilson et al. 2010, PLoS Biology.

Citation: "Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India,"/Jeffrey A. Wilson, Dhananjay M. Mohabey, Shanan E. Peters, Jason J. Head/Public Library of Science Biology, Mar. 2010, Vol. 8, Issue 3.

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Stone Age Engravings Found on Ostrich Shells

Posted: 01 Mar 2010 01:37 PM PST


Long before human communication evolved into incessant tapping on computer keys, people scratched on eggshells.

sciencenewsDon't laugh—researchers say a cache of ostrich eggshells engraved with geometric designs demonstrates the existence of a symbolic communication system around 60,000 years ago among African hunter-gatherers.

The unusually large sample of 270 engraved eggshell fragments, mostly excavated over the past several years at Diepkloof Rock Shelter in South Africa, displays two standard design patterns, according to a team led by archaeologist Pierre-Jean Texier of the University of Bordeaux 1 in Talence, France. Each pattern enjoyed its own heyday between approximately 65,000 and 55,000 years ago, the investigators report in a paper to be published this week in the Proceedings of the National Academy of Sciences.

Researchers already knew that the Howiesons Poort culture, which engraved the eggshells, engaged in other symbolic practices, such as engraving designs into pieces of pigment, that were considered to have been crucial advances in human behavioral evolution. But the Diepkloof finds represent the first archaeological sample large enough to demonstrate that Stone Age people created design traditions, at least in their engravings, Texier says.

Evidence of intentionally produced holes in several Diepkloof eggshells indicates that ancient people made what amounted to canteens out of them, a practice that researchers have documented among modern hunter-gatherers in southern Africa.

The engraved patterns probably identified the eggshells as the property of certain groups or communities, Texier proposes.

"The Diepkloof engravings were clearly made for visual display and recognized as such by a large audience comprising members of a community, and probably members of related communities," comments University of Bordeaux 1 archaeologist Francesco d'Errico, who was not involved in the new study.

D'Errico participated in the recent unearthing of 13 pieces of engraved pigment at South Africa's Blombos Cave dating to between 100,000 and 75,000 years ago. Along with perforated sea shells and other personal ornaments previously excavated in Africa and the Middle East, these discoveries show that items holding symbolic meaning were made more than 60,000 years ago by both modern humans and Neandertals.

Even more exciting, according to archaeologist Curtis Marean of Arizona State University in Tempe, is the presence of drinking spouts in the South African eggshells. Water containers opened a new world of travel across arid regions for ancient people, he notes.

"The ability to carry and store water is a breakthrough technological advance, and here we have excellent evidence for it very early," Marean says. "Wow!"

Eggshell fragments from the oldest sediment layers at Diepkloof display a hatched-band motif. These engravings consist of two long, parallel lines intersected by varying numbers of short lines. Some specimens contain one hatched band, while others display remnants of two or three. Engravers always fashioned parallel lines first and then inserted regularly spaced intersecting lines, Texier says.

Eggshells from younger soil layers at Diepkloof contain patterns consisting of deeply engraved, parallel lines that sometimes converge or intersect. One eggshell fragment from these layers exhibits a different pattern—slightly curved horizontal lines that cross a central, vertical line.

Of the many Howiesons Poort sites in southern Africa that have yielded ostrich eggshells, only Diepkloof shows evidence of stylistic engraving traditions, Texier says.

Image: Pierre-Jean Texier, Diepkloof project.

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Backpack Hydroelectric Plant Gives You 500 Watts on the Move

Posted: 01 Mar 2010 12:57 PM PST

wmspp1A human-portable hydroelectric generator that weighs about 30 pounds and generates 500 watts of power may soon be a new option for off-grid power.

Developed by Mailbu's Bourne Energy, the Backpack Power Plant can create clean, quiet power from any stream deeper than four feet.

The company showed off its more rugged, militarized version of the Backpack Power Plant at the Cleantech Forum in San Francisco last week. Bourne Energy CEO, Chris Catlin, estimates the system will cost $3,000 after it goes into production.

"The BPP-2, which operates silently with no heat or exhaust emissions, is 40 percent less visible during operation and can also be bottom mounted to be totally invisible," the company maintains.

Off-grid solar cells are also quiet, but they don't make much power relative to the mini-turbine. For example, one commercially available foldable solar panel measures about 12 square feet and produces 62 watts of peak power. You'd need 60 square feet of panels to get the same peak power as the BPP-2 and the panels would only generate electricity while the sun was shining.

To install the civilian BPP, you would dig two trenches on opposite sides of a river and insert a lightweight anchor. Then, you'd run a synthetic rope between the anchors and the BPP. Catlin said they'd designed the system to work like the high-tension mooring systems that hold up floating oil rigs.

The militarized version of the BPP has been designed to work with a variety of flow rates. The civilian version was designed to function best in streams moving at 2.3 meters (7.5 feet) per second.

The civilian market for a $3,000 mini hydro system might not be huge in the industrialized world, but Catlin hopes the plant will find willing customers in developing nations and the military.

"This can bring a cheap, highly portable energy technology to remote areas and remote villages," Catlin told Wired.com.

Bourne is currently looking for $4 million in venture capital to take the BPP from prototype to production.

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DNA Analysis Shows Polar Bears Have Adapted Quickly in the Past

Posted: 01 Mar 2010 11:17 AM PST


Genetic analysis of an ancient polar bear fossil has formally dated the species' birth to 150,000 years ago, shortly before an Ice Age thaw produced a climate comparable to what's expected in a globally warmed future.

"They've certainly experienced climate changes before," said Charlotte Lindqvist, a biologist at the State University of New York at Buffalo and co-author of the analysis, published March 1 in the Proceedings of the National Academy of Sciences. "The big question is whether they're going to be able to survive in the future."

Polar bears have become an icon of climate change concerns, with environmentalists and many researchers predicting their imminent doom. The bears spend their summers hunting seals on fast-dwindling Arctic sea ice. As the ice melts, the bears starve.

According to a 2007 United States Geological Survey review, two-thirds of all polar bears will likely vanish [pdf] by the mid-21st century. An international consortium of arctic researchers has said that "the survival of polar bears as a species is difficult to envisage" [pdf] if summer sea ice is lost. That may happen within several decades.

However, critics of those conclusions say polar bears may prove more adaptable than expected.

In 2007, University of Iceland geologist Ólafur Ingólfsson, co-author on the new study, found a fossilized polar bear jawbone on the Arctic Ocean island of Svalbard. He estimated its age at between 110,000 and 130,000 years. Until then, the species was thought to be about 90,000 years old. The new estimate meant they'd survived the Eemian, a period of globally high temperatures that started 130,000 years ago, ending the next-to-last Ice Age, and lasted for 15,000 years until the last Ice Age began. Earth scientists consider the Eemian a preview of climate changes expected in the next few centuries.

In the recent study, Ingólfsson and Lindqvist compared DNA extracted from the fossil's mitochondria — cell structures that float outside the nucleus and have their own genetic material — with mitochondrial DNA from modern polar bears and brown bears, their closest relative. They used the amount of genetic change that occurred over the last 130,000 years to calculate the genetic mutation rate and then extrapolated the same rate back in time. The result suggests the two species split around 150,000 years ago.

Structural evidence and dietary mineral traces from the jawbone show that 20,000 years after the split, the animal was already as big as a modern polar bear, ate a similar diet rich in marine mammals, and lived in similar regions. The new findings imply these adaptations took place in a relatively short time.

If the species changed so dramatically once, perhaps it might change so dramatically again. But Lindqvist warned against drawing premature conclusions.

"In evolutionary terms, they adapted in a short period of time to the specialized species they are today. But I'm talking tens of thousands of years, not decades," she said.

Rather than physically changing, she expects polar bears to gather in the last few hospitable places on Earth. Such regions likely provided refuge during the Eemian, said Lindqvist.

Image:Steve Hillenbrand/USFWS

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Citation: "Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear," by Charlotte Lindqvist, Stephan Schuster, Yazhou Sun, Sandra Talbot, Ji Qi, Aakrosh Ratan, Lynn Tomsho, Lindsay Kasson, Eve Zeyl, Jon Aars, Webb Miller, Ólafur Ingólfsson, Lutz Bachmann, and Øystein Wiigd. Proceedings of the National Academy of Sciences, Vol. 107 No. 9, March 1, 2010.

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

Insect Character Recognition: Computers See Bees Like We Can’t

Posted: 01 Mar 2010 03:00 AM PST

Studying animal behavior used to mean traveling into the wild and making detailed notes about gorillas. Now, biologist-coders are figuring out how to use computer vision techniques to convert the myriad motions of creatures large and small into crunchable data.

Researchers are figuring out how track the movements of insects such as Drosophila, the fruit fly, in order to answer the question: How do we define behavior?

"A fundamental problem that we haven't done that much work on in biology is quantifying behavior," said Kristin Branson, a fellow at Howard Hughes Medical Institute's Janelia Farm Research Campus. "We have a much better handle on the very low-level things, molecular, genetic, and neural than we do at the global, large-scale level of behavior."

We know what behavior is: It's what animals do. But quantifying it isn't easy, even for tiny creatures with equally tiny brains. Big data came to branches of science like particle physics many years ago, but some realms of biology have remained resistant to the computational techniques that mark so many other disciplines. The data for a lot of behavioral biology remains simple human observations — or results from ingenious Rube Goldbergian experimental apparatus. Either way, it's hard to do what Branson calls high-throughput behavioral experiments.

So, while researchers mapped the fruit fly's genome in 2000 and know its genetics better than almost any other creature, the relationship between its genes, its brain, and its behavior is still hard to understand.

At Janelia, Branson's lab head, Gerry Rubin, is mapping out the circuits in the fruit fly brain. His team has created thousands of transgenic flies that allow them to test the individual circuits. But while we know what we've done, it's hard to tell what it makes the the flies do.

Let's say some genetic change is made to the fruit flies and they chase one another around 20 percent more often than an unaltered specimen. If you're the fly, that's an important change, but how could a human researcher ever detect that 20 percent? It's not like counting how many times a monkey mother nurses.

"How do we say in a quantitative way how the behavior has changed?" Branson said. "You wouldn't notice that if you were just watching."

To solve that problem, Branson and collaborators in Michael Dickinson's lab at Caltech, where she was a postdoc, built the Caltech Multiple Fly Tracker. It's a piece of software that converts infrared video of up to 50 flies inside a special arena into movement data. The flies become small triangles in space and their behavior is plotted and recorded.

Another Dickinson lab postdoc, Andrew Straw, has even designed a 10-camera system he calls Flydra to track free moving, flying insects.

Some of what they've found is odd and unexpected. After recording male and female flies at Caltech, they mined the data for interesting differences between them.

"And if you looked at how often the fly turned, you could tell the gender of the fly with better than 90 percent accuracy," Branson said.

It's unclear why such a behavioral difference exists, but it does, and likely always has, hidden within the masses of data that our eyes receive when we watch a bunch of flies moving around.

All sorts of other behaviors emerge from the data, if you just watch for long enough.

"Fruit flies may not be as interesting as gorillas on the surface to humans. They just seem like little gnat sized things," said Serge Belongie, a computer vision specialist at the University of California San Diego, who was Branson's Ph.D. advisor. "But you run this tracker long enough and there is some pretty interesting courtship competitiveness behavior. It's basically reality TV for fruit flies with some interesting stuff happening."

"We're finding subtle differences between individual flies now," Branson agreed. "If you're being not very technical about things, you can say that these flies have different personalities. In biology we try not to do it, but it's a fun way to think of it."

While computer vision is more familiar to people as the technology behind Optical Character Recognition or social media applications, it may work better with animal tracking than it does in some other settings. That's because researchers can design experiments that make acquiring clean data easier.

By designing the algorithms and the image acquisition apparatus together, it makes the most difficult computer vision problems disappear.

"If you think about people-tracking, you can solve it at the 80 percent solved level because you don't have complete control of your environment," Branson said. "I want things to work at 99 or 100 percent. I feel like we can really solve the problem well enough that people will use these programs, and it will be a very clean solution."

While Branson's work qualifies as basic science, computer vision insect monitoring could have more immediate implications. Take beekeeping, which has been plagued by colony collapse disorder. Intel researcher Lily Mummert, a backyard apiarist, built a tracking tool that could identify bees coming and going from her own hive. Counting the number of bees coming into and out of it, and perhaps some other data, could yield important insights about the life and times of a beehive, she said.

Ideally, all the equipment could be miniaturized and stuck into a little unit that would beam data up.

"I'd like to see a little unit, a camera, full-on board processor, and a little wireless transmitter so you could just mule off the count," Mummert said. "That thing could be a really versatile platform for all kinds of environmental monitoring. You could apply it to bees, you could apply it to anything."

All kinds of insect- and animal-monitoring experts got together for a workshop in late 2008, and they plan to do it again this year in Istanbul during the International Conference on Pattern Recognition.

With video cameras and computational ability getting cheaper and better, quantifying animal behavior will undoubtedly improve. It's possible that before too long, there will be a new encyclopedia of knowledge on the biology block: the behaviorome.

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