Wednesday, 9 March 2011

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Physics of Pruney Fingers Revealed

Posted: 08 Mar 2011 04:19 PM PST

An exploration of mathematical shapes could explain why skin gets wrinkled after too much time in the tub. Understanding the geometry of wrinkly skin could help design new materials that can stretch out without losing strength.

"The paper explains a mechanism that can explain the structural stability of keratin in skin and its ability to absorb very large quantities of water," said mathematician Gerd Schröder-Turk of the University of Erlangen-Nürnberg in Germany, who was not involved in the new work. "This is a major breakthrough."

Scientists and frequent bathers know that skin can absorb a tremendous amount of water, and still be a strong barrier between our bodies and the harsh outside world.

"Your skin wrinkles, yet it maintains its structure," said mathematician Myfanwy Evans of the Australian National University, lead author of the new study. "It doesn't just fall apart and dissolve into the water."

The skin's resilient stretchiness comes from an intricate network of fibrous proteins called keratin, which make up the outermost layer of the skin, as well as hair and nails. Scientists knew that skin's keratin networks were important, but the arrangement of fibers was uncertain.

Now, Evans and Australian National University colleague Stephen Hyde may have found a solution. They describe their stringy skin model in the March 8 Journal of the Royal Society Interface.

"It explains a lot of mechanical features that hadn't really been able to be explained before," Evans said.


The researchers stumbled upon the new model in a purely math-based search for interesting topological shapes. Evans studies a class of beautiful mathematical shapes called Gyroids, which show up all over the natural world, from lipid membranes to butterfly wings.

"It's an interesting fusion of maths and experimental science," Evans said. "These are popping up everywhere."

Using computer simulations, Evans and Hyde explored what would happen if you took infinitely long threads and wove them through the labyrinth of the Gyroid surface, then took the surface away. Some of the resulting 3-D woven structures were so tangled that none of the threads could move without breaking the connections between individual threads. If keratin were arranged this way, Evans says, our skin would lose its strength when it got wet.

"Losing contacts between keratin fibers means losing structural rigidity," she said.

But other weavings could expand, with threads straightening and sliding along each other without losing contact. One of these, which Evans and Hyde call G129, could swell to fill a volume seven times greater than its original shape, while keeping all its fiber connections intact — just like skin.

Suggestively, the model's version of keratin networks in dry skin matches real data almost exactly, Evans says.

"That was quite convincing evidence that it's highly likely that this model really does work," she said.

Although the model hasn't made it far from the world of abstract math, Evans and colleagues hope their models of expandable networks of fibers could be used in the bottom-up design of custom materials with controllable stretchiness. These materials could be useful for things like bandages, bulletproof vests and artificial skin, she suggests.

"This could be a really good target for bio-inspired materials," she said. "It's not a matter of testing it in the lab, it's a matter of understanding its geometry in order to understand its physical properties…. We hope this paper will put that idea out there, and maybe lead to some new interesting materials."

Images: 1) Flickr/Mathew Wilson. 2) Evans and Hyde, 2011. Video: Gerd Schröder-Turk.

"From three-dimensional weavings to swollen corneocytes." Myfanwy Evans and Stephen Hyde. Journal of the Royal Society Interface, March 8, 2011. DOI: 10.1098/rsif.2010.0722

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Photo: Mad Dash to Catch Space Shuttle Crossing the Sun

Posted: 08 Mar 2011 12:32 PM PST

Intrepid astrophotographer Alan Friedman raced against time to reach exactly the right spot at the right fraction of a second to snap this stunning photo of the International Space Station, with the Space Shuttle Discovery attached, crossing the sun.

Friedman drove 1,800 miles from his home in Buffalo, New York to the annual Winter Star Party in the Florida Keys, "for the steady skies, warm temperatures and the company of good astronomy friends," he wrote on his website. "But when I heard that the ISS would transit the sun nearby … I had to give it a try."

The transit would be visible at 2:39 p.m. on March 1 from a location 20 miles to the north of the star-party site. The entire crossing would last just 0.2 seconds. Friedman was scheduled to give a talk about astrophotography from 12:30 to 1:30 pm. As soon as his talk was over, Friedman jumped in the car with fellow astrophotographers Brian Shelton and Mark Beale and raced after the sun.

"We got set up just in time to catch it," Friedman wrote. "I underestimated the narrowness of this event … another 500 feet and we would have missed it entirely. Lucky day!"

Friedman shoots his startlingly sharp sun photos with a 3.5-inch telescope he calls Little Big Man and a filter that only lets in light emitted by hydrogen. He then inverts the images, making the light spots dark and the dark spots light, which gives the sun a swirling, textured appearance.

Most of the time, Friedman shoots the sun from his backyard. "I think that is a real fascination with my work," he said in an e-mail to "With all the wonderful satellites and missions out there taking close-up images of our solar system neighbors … it is still possible to do it yourself and even come up with something magical now and again."

While in Florida, Friedman also caught a puff of plasma detaching from the edge of the sun (below). Although it looks serene, such plasma clouds can weigh tens of billions of tons, and can flood the inner solar system with hot, charged matter if they detach from the sun for good.

Images: Alan Friedman

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Experts Push NASA to Focus on Search for Life

Posted: 08 Mar 2011 10:37 AM PST

The search for life in the solar system, whether in rocks from Mars or on a Jovian moon, tops the wish list of a panel of space scientists convened by the National Research Council. Mindful of shrinking budgets, the panel has issued hard-nosed recommendations that identify which planetary science missions NASA should fly in the decade beginning 2013. Even some top-rated missions should be either deferred or outright canceled if their estimated costs can't be significantly cut, the panel says in a report released March 7.

Among its big missions, the panel says, NASA should give highest priority to the Mars Astrobiology Explorer-Cacher. This project would be the first of three missions designed to collect Martian samples and bring them to Earth for analysis of any evidence of life forms. But the panel of space scientists recommends that the mission should go forward only if NASA's cost can be limited to $2.5 billion; $1 billion less than the project's estimated price tag in fiscal year 2015 dollars (adjusted for inflation). The European Space Agency and NASA, which will jointly run the mission, should work together to reduce the high cost, the report suggests. One possibility is to include one large robot instead of two.

"I'm ready to hit the ground running with Europe to see if we can do something with that first priority," says Ed Weiler, NASA's associate administrator for science in Washington, D.C.

NASA's Jupiter Europa Orbiter also received a nod from the panel, which ranked the mission as the second-highest priority among large projects. The craft would carry a suite of instruments to determine if Jupiter's moon Europa has an ocean — a possible haven for life — buried beneath its icy surface, as many scientists suspect. But the panel says the mission should fly only if the project's current estimated cost of $4.7 billion is reduced and if NASA increases its planetary science budget. The panel did not say specifically how much to cut from the Europa mission in order to maintain funding of other projects, but did spell out a 5 percent boost to NASA's planetary science research funding compared with fiscal year 2011. The panel also recommends that the planetary science budget should remain 1.5 percent above inflation for the remainder of the decade.

Exploring the structure, composition and atmosphere of Uranus with an orbiter and probe also earned a high mark from the panel, which rated the project third among NASA's large missions. But the panel recommends the mission be reduced in scope or canceled if it rises above its estimated $2.7 billion cost.


The report also encourages NASA to fund two new midsize missions among five candidates but did not say which to choose. The five possibilities include a Venus lander, a probe that would descend though Saturn's atmosphere, missions that would sample either the surface of a comet or a large basin at the moon's southern pole, and a craft that would study the small objects that trail or lead Jupiter in its orbit around the sun. The cap on these missions should be raised slightly, from $1.05 billion including launch costs in fiscal 2015 dollars to $1 billion excluding launch costs, the panel recommends.

Among the least costly missions, the committee recommends that NASA continue to support the ESA/NASA Mars Trace Gas Orbiter, set for launch in 2016, as long as currently negotiated costs and responsibilities between the two space agencies remain unaltered.

The report also urged the National Science Foundation to complete the Large Synoptic Survey Telescope, which will not only probe the nature of dark matter and dark energy but aid in tracking near-Earth asteroids.

Previous reports recommending astrophysics and planetary science missions have been criticized for using cost estimates that were too low. As a result, NASA could not always fund the projects that scientists had pushed for, says planetary scientist Steve Squyres of Cornell University, who chaired the panel. This time both NASA and the National Science Foundation, which cosponsored the report, were specific about keeping recommendations and cost estimates in line with budget realities and requesting fallback options in case funding was less than expected.

"We took the marching orders very seriously," Squyres said. "We tried very, very hard to be reasonable."

Image: A National Research Council panel has recommended that NASA fund the proposed Jupiter Europa Orbiter, shown here, but only if scientists reduce the mission's cost, now estimated at $4.7 billion. (JPL/NASA)

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Data as Art: 10 Striking Science Maps

Posted: 08 Mar 2011 04:00 AM PST

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The computer age triggered a seemingly endless stream of scientific data, but such incoming mountains of information come at a cost. The more data you amass, the tougher it is to comprehend what you're dealing with.

In a push for better perspective, a group of information scientists in 2005 created a decade-long competitive art exhibit called Places & Spaces: Mapping Science. From artistic pop-culture plots to illustrations of the state of scientific collaboration (above), the founders hope winning entries inspire researchers to present their troves of data in clever and digestible ways.

"Good science maps give you a holistic understanding of how the data is structured," said information scientist Katy Börner of Indiana University, a founder and curator of the exhibit. She is also author of the Atlas of Science, a collection of the maps gathered over the years. "You don't just have to use maps to find your way home. They can be ways to get global overviews on topics."

The exhibit's advisory board follows a theme and some core criteria to pick 10 winners each year. This year's winning entries for the theme "science maps as visual interfaces to digital libraries" were announced this week. Exhibit-ready versions of the maps are scheduled for display in mid-June.

We showcase some of our favorite winners here, in addition to a few that didn't make the final cut. Some maps are too small to properly appreciate here, but we include links to high-resolution versions for each of them.


Scientific Collaboration

Inspired by a map of 500 million Facebook friends published in December 2010, research analyst Olivier H. Beauchesne created this winning visualization of international collaboration that occurred from 2005 through 2009.

Each arc represents a collaboration between scientists in different cities mined from studies, books and trade journals found in Elsevier's Scopus database. Dense nodes of science emerge in the Americas, Europe and Japan.

Image: Olivier H. Beauchesne/Science-Metrix [high-resolution version]

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