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Johnald's Fantastical Daily Link Splurge

2011-06-15T13:33:00.001-07:00

Johnald's Fantastical Daily Link Splurge

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Posted: 15 Jun 2011 01:28 PM PDT

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Johnald's Fantastical Daily Link Splurge

2011-03-19T13:34:00.001-07:00

Johnald's Fantastical Daily Link Splurge

Possible Early Warning Sign for Market Crashes
Understanding Japan’s Nuclear Crisis
Spacecraft Swings Into First Orbit Around Mercury

Possible Early Warning Sign for Market Crashes

Posted: 18 Mar 2011 10:11 AM PDT

Complexity researchers who study the behavior of stock markets may have identified a signal that precedes crashes.

They say the telltale sign is a measure of co-movement, or the likelihood of stocks to move in the same direction. When a market is healthy, co-movement is low. But in the months and years before a crash, co-movement seems to grow.

Regardless of whether stock prices go up or down or stay the same, they do so in tandem. People are copying each other, and a small nudge can send everyone in the same direction. The system appears primed for collapse.

"One of the most important things happening now is that economists are trying to understand, what is systemic risk? When is the entire system vulnerable to disaster? Our results show that we have a direct, unambiguous measure of that vulnerability," said Yaneer Bar-Yam, president of the New England Complex Systems Institute.

Seen through an econophysicist's eyes, a stock market panic is an avalanche.

Bar-Yam's findings, released Feb. 13 on arXiv, are part of an emerging research field known as econophysics. It applies to economics insights from the physical world, especially from systems in which networks of interacting units produce radical collective behaviors.

Heated water turning to gas is one such behavior, known technically as a phase transition. Another is snow gathering into an avalanche. Seen through an econophysicist's eyes, a stock market panic is an avalanche, too.

Using a phase-transition model, Bar-Yam's group analyzed patterns of movement in the stock market. At the beginning of the 2000s, co-movement was low. On any given day, about half the stocks were moving up or down. By 2008, shortly before the crash, co-movement was absolute. People were no longer making independent decisions, but copying others.

"There's a break point where the system is flat — equally likely to have any number of stocks moving together on a particular day," said Bar-Yam. "And if you see these collective behaviors building up, then you know you're in trouble."

At top, a metric of stock co-movement during the 2000s. As it gets closer to zero, individual stocks are more likely to move up or down in the same direction. At bottom is the Russell 3000 Index.

After expanding the analysis back to 1985, they found periods of increasing co-movement within four years before each major crash, though never so starkly as before 2008. The researchers also propose that increasing co-movement fuels large, single-day market drops.

Jeffrey Fuhrer, researcher director at the Federal Reserve Bank of Boston, called the results intriguing but preliminary, requiring more rigorous statistical examination.

"As an initial pass, it's an interesting idea," he said, but doesn't yet distinguish when investors respond rationally and independently to the same information, such as a rise in fuel prices, or move reflexively as a herd.

However, the line between those trends may be blurry. According to Bar-Yam's group, external stresses — fuel prices, war, the perception of market bubbles — may increase the market sensitivity, making it more vulnerable to panic. So might changes in the very structure of markets, from their increasingly interlocking nature to instant-communication tools.

Fuhrer's cautions were echoed by econophysicist Tobias Preis of the Swiss Federal Institute of Technology. "One should be very careful about generalization to predict future crises," he said. "The most important point is to quantify this risk. That would be a huge step forward."

If co-movement does prove to be a reliable early warning signal, it's an open question how to make use of it. "That is one of the $64,000 questions," said Fuhrer.

Whereas bailing out a company is relatively simple, intervening in the dynamics of a system is not. But the first step is understanding that markets follow rules we're just beginning to understand.

"The financial crisis has shown that mainstream economic theories have limitations that need to be overcome," said Dirk Helbing of the Swiss Federal Institute of Technology, who specializes in modeling crowd behavior. "Economic systems have become much more complex, and complex systems have certain features — cascading effects, systemic shifts. This calls for new theoretical approaches."

See Also:

Citation: "Predicting economic market crises using measures of collective." By Dion Harmon, Marcus A. M. de Aguiar, David D. Chinellato, Dan Braha, Irving R. Epstein, Yaneer Bar-Yam. arXiv, Feb. 13, 2011.

Understanding Japan’s Nuclear Crisis

Posted: 18 Mar 2011 09:00 AM PDT

By John Timmer, Ars Technica

Following the events at the Fukushima Daiichi nuclear reactors in Japan has been challenging. At best, even those present at the site have a limited view of what's going on inside the reactors themselves, and the situation has changed rapidly over the last several days. Meanwhile, the terminology involved is somewhat confusing—some fuel rods have almost certainly melted, but we have not seen a meltdown; radioactive material has been released from the reactors, but the radioactive fuel currently remains contained.

Over time, the situation has become a bit less confused, as cooler heads have explained more about the reactor and the events that have occurred within it. What we'll attempt to do here is aggregate the most reliable information we can find, using material provided by multiple credible sources. We've attempted to confirm some of this information with groups like the Nuclear Regulatory Commission and the Department of Energy but, so far, these organizations are not making their staff available to talk to the press.

Inside a Nuclear Reactor

Nuclear reactors are powered by the fission of a radioactive element, typically uranium. There are a number of products of this reaction, but the one that produces the power is heat, which the fission process gives off in abundance. There are different ways to extract electricity from that heat, but the most common way of doing so shares some features with the first steam engines: use it to boil water, and use the resulting pressure to drive a generator.

Radioactivity makes things both simpler and more complex. On the simpler side, fission will readily occur underwater, so it's easy to transfer the heat to water simply by dunking the nuclear fuel directly into it.

In the reactor design used in Japan, the fuel is immersed in water, which boils off to generate power, is cooled, and then returns to the reactor. The pressure vessel and primary containment keep radioactivity inside. (Ars Technica)

Unfortunately, the radioactivity complicates things. Even though the fuel is sealed into rods, it's inevitable that this water will pick up some radioactive isotopes. As a result, you can't just do whatever you'd like with the liquid that's been exposed to the fuel rods. Instead, the rods and water remain sealed in a high-pressure container and linked pipes, with the hot water or steam circulated out to drive machinery, but then reinjected back into the core after it has cooled, keeping a closed cycle.

The water recirculation doesn't just let us get power out of the reactor; it's essential to keeping the reactor core cool. Unless the heat of decay is carried away from the core, its temperature will rise rapidly, and the fuel and its structural support will melt.

The Fission Reaction

Uranium ore. (Marchin Wichary/Flickr)

On its own, the uranium isotope used in nuclear reactors will decay slowly, releasing a minimal amount of heat. However, one of the decay products is a neutron, which can strike another atom and induce that to split; other neutrons are produced as the products of that split decay themselves. At high enough densities, this chain reaction of neutron-induced fission can produce a nuclear explosion. In a nuclear reactor, the fuel density is low enough that this isn't a threat, and the rate of the fission can be controlled by inserting or removing rods of a material that absorbs neutrons, typically boron.

Completely inserting control rods to limit uranium's fission, however, doesn't affect what's happened to the products of previous reactions. Many of the elements that are produced following uranium's split are themselves radioactive, and will decay without needing any encouragement from a neutron. Some of the neutrons from the reactor will also be absorbed by atoms in the equipment or cooling water, converting those to radioactive isotopes. Most of this additional radioactive material decays within the span of a few days, so it's not a long-term issue. But it ensures that, even after a reactor is shut down by control rods, there's enough radioactive decay around to keep things hot for a while.

All of which makes the continued operation of the plant's cooling system essential. Unfortunately, cooling system failures have struck several of the reactors at Fukushima Daiichi.

Surviving the Quake, But Not the Tsunami

Because cooling is so essential to a plant's operation, there are a few layers of backups to keep the pumps running. For starters, even if the reactors themselves are taken offline, the coolant pumps can receive power from offsite; this option was eliminated by the earthquake itself, which apparently cut off the external power to Fukushima. The earthquake also triggered a shutdown of the reactors, removing the obvious local source of power to the pumps. At this point, the first backup system kicked in: a set of on-site generators that burn fossil fuels to keep the equipment running.

Those generators lasted only a short while before the tsunami arrived and swamped them, flooding parts of the plant's electrical system in the process. Batteries are in place to allow a short-term backup for these generators; it's not clear whether these failed due to the problems with the electrical system, or were simply drained. In any case, additional generators were slow to arrive due to the widespread destruction, and didn't manage to get the pumps running again when they did.

As a result, the plants have been operating without a cooling system since shortly after the earthquake. Even though the primary uranium reaction was shut down promptly, the reactor cores have continued to heat up due to secondary decay products.

Ugly Possibilities

Without cooling, there are a number of distinctly ugly possibilities. As water continues to be heated, more steam will be generated within the reactor vessel, increasing the pressure there, possibly to the point where the vessel would fail. The reactor vessel would burst into a primary containment vessel, which would limit the immediate spread of radioactive materials. However, the rupture of the reactor vessel would completely eliminate any possibility of restoring the coolant system, and might ultimately leave the reactor core exposed to the air.

And that would be a problem, since air doesn't carry heat away nearly as efficiently as water, making it more likely that the temperatures would rise sufficiently to start melting the fuel rods. The other problem with exposing the fuel rods to air is that the primary covering of the rods, zirconium, can react with steam, reducing the integrity of the rods and generating hydrogen.

To respond to this threat, the plant's operators took two actions, done on different days with the different reactors. To begin with, they attempted to pump cold sea water directly into the reactors to replace the boiled-off coolant water. This was not a decision made lightly; sea water is very corrosive and will undoubtedly damage the metal parts of the reactor, and its complex mixture of contents will also complicate the cleanup. This action committed the plant operators to never running it again without a complete replacement of its hardware. As an added precaution, the seawater was spiked with a boron compound in order increase the absorption of neutrons within the reactor.

The second action involved the bleeding off of some pressure from the reactor vessel in order to lower the risk of a catastrophic failure. This was also an unappealing option, given that the steam would necessarily contain some radioactivity. Still, it was considered a better option than allowing the container to burst.

This decision to bleed off pressure ultimately led to the first indications of radioactivity having escaped the reactor core and its containment structure. Unfortunately, it also blew the roof off the reactor building.

Hard Choices to Bad Results

As seen in some rather dramatic video footage, shortly after the pressure was released, the buildings housing the reactors began to explode. The culprit: hydrogen, created by the reaction of the fuel casing with steam. The initial explosions occurred without damaging the reactor containment vessel, meaning that more significantly radioactive materials, like the fuel, remained in place. Larger increases in radioactivity, however, followed one of the explosions, indicating possible damage to the containment vessel, although levels have since fluctuated.

However, the mere presence of so much hydrogen indicated a potentially serious issue: it should only form if the fuel rods have been exposed to the air, which indicates that coolant levels within the reactor have dropped significantly. This also means that the structural integrity of the fuel rods is very questionable; they've probably partially melted.

Part of the confusion in the coverage of these events has been generated by the use of the term "meltdown." In a worst-case scenario, the entire fuel rod melts, allowing it to collect on the reactor floor, away from the moderating affect of any control rods. Its temperature would soar, raising the prospect that the material will become so hot that it will melt through the reactor floor, or reach a source of water and produce an explosive release of steam laced with radioactive fuel. There is no indication that any of this is happening in Japan at the moment.

Still, the partial melting of some fuel does increase the chances that some highly radioactive material will be released. We're nowhere near the worst case, but we're not anywhere good, either.

An additional threat has recently become apparent, as one of the inactive reactors at the site suffered from an explosion and fire in the area where its fuel is being stored. There is almost no information available about how the tsunami affected the stored fuel. Hydrogen is again suspected to be the source of the explosion, which again suggests that some of the fuel rods have been exposed to the air and could be melting. It's possible that problems with the stored fuel contributed to the recent radiation releases, since there isn't nearly as much containment hardware between the storage area and the environment.

Again, plans have been made to add sea water to the storage area, both by helicopter drops attempted earlier today, and through standard firefighting equipment.

Where We Stand

So far, the most long-lived radioactive materials at the site appear to remain contained within the reactor buildings. Radioisotopes have and continue to escape containment, but there's no indication yet that these are anything beyond secondary decay products with short half-lives.

Although radiation above background levels has been detected far from the reactor site, most of this has been low-level and produced by short-lived isotopes. Prevailing winds have also sent a lot of the radioactive material out over the Pacific. As a result, most of the problems with radioactive exposure have been in the immediate vicinity of the Fukushima Daiichi reactors themselves, where radiation has sometimes reached threatening levels; it's been possible to hit a yearly safe exposure limit within a matter of hours at times. Areas around the reactors have been evacuated or subject to restrictions, but it's not clear how far out the areas of significant exposure extend, and they may change rapidly.

All of this is severely complicating efforts to get the temperatures under control. Personnel simply can't spend much time at the reactor site without getting exposed to dangerous levels of radioactivity. As a result, all of the efforts to get fresh coolant into place have been limited and subject to interruption whenever radiation levels spike. The technicians who continue to work at the site are putting their future health at risk.

There is some good news here, as each day without a critical failure allows more of the secondary radioactive materials to decay, lowering the overall risk of a catastrophic event. In the meantime, however, there's little we can do to influence the probability of a major release of radioactive material. Getting seawater into the reactors has proven to be hit-or-miss, and we don't have a strong sense of the structural integrity of a lot of the containment buildings at this point; what's happening in the fuel storage areas is even less certain. In short, our only real option is to try to get more water in and hope for the best.

Future of Nuclear Energy

Nuclear power plays a big role in most plans to limit the use of fossil fuels, and the Department of Energy has been working to encourage the building of the first plants in decades within the US. The protracted events in Japan will undoubtedly play a prominent role in the public debate; in fact, they may single-handedly ignite discussion on a topic that the public was largely ignoring. The take-home message, however, is a bit tough to discern at this point.

In some ways, the Japanese plants, even though they are an old design, performed admirably. They withstood the fifth-largest earthquake ever recorded, and the safety systems, including the automatic shutdown and backup power supplies, went into action without a problem. The containment systems have largely survived several hydrogen explosions and, so far, the only radioactive materials that have been released are short-lived isotopes that are concentrated in the plant's vicinity. If things end where they are now, the plants themselves will have done very well under the circumstances.

But, as mentioned above, ending where we are now is completely beyond our control, and that highlights some reasons why this can't be considered a triumph. Some of the issues are in the design. Although the plant was ready for an extreme event, it clearly wasn't designed with a tsunami in mind—it is simply impossible to plan for every eventuality. However, this seems to be a major omission given the plant's location. It also appears that the fuel storage areas weren't nearly as robustly designed as the reactors.

Once the cooling crisis started, a set of predictable issues cropped up. We can never send humans inside many of the reactor areas, leaving us dependent upon monitoring equipment that may not be working or reliable during a crisis. And, once radiation starts to leak, we can't send people to many areas that were once safe, meaning we've got even less of an idea of what's going on inside, and fewer points to intervene at. Hardware that wasn't designed for some purposes, like pumping sea water into the reactor vessel, hasn't worked especially well for the emergency measures.

On balance, the safety systems of this reactor performed reasonably well, but were pushed up against a mixture of unexpected events and design limits. And, once anything starts to go wrong with a nuclear reactor, it places the entire infrastructure under stress, and intervening becomes a very, very difficult thing to do.

This latter set of issues mean that the surest way to build a safe nuclear plant is to ensure that nothing goes wrong in the first place. There are ways to reduce the risk by adding more safety and monitoring features while tailoring the design to some of the most extreme local events. But these will add to the cost of a nuclear plant, and won't ever be able to ensure that nothing goes wrong. So, deciding on if and how to pursue expanded nuclear power will require a careful risk analysis, something the public is generally ill-equipped for.

Top image: Ars Technica.

Source: Ars Technica.

Posted: 18 Mar 2011 08:14 AM PDT

NASA's Messenger spacecraft swung into position around Mercury Thursday night, making it the first spacecraft ever to orbit the innermost planet.

Engineers at the Johns Hopkins University Applied Physics Laboratory in Maryland, 96 million miles from Mercury, received the signal confirming that Messenger (MErcury Surface, Space ENvironment, GEochemistry and Ranging) had completed its final maneuver at 9:10 pm EDT.

To slow down enough to get caught in Mercury's gravitational field, Messenger fired its main thruster for 15 minutes. The burn slowed the spacecraft by 1,929 mph and used up 31 percent of its original fuel supply.

After finishing the burn, Messenger rotated to face the Earth by 9:45 p.m., and started transmitting data. Engineering and operations teams confirmed the maneuver went according to plan.

The event marks the end of a 6½-year journey for Messenger, which has made 12 laps around the solar system, two flybys past Earth, one past Venus and three past Mercury since launching in August 2004.

Although engineers still need to do some analysis to figure out the spacecraft's exact orbit, they expect Messenger to swoop around Mercury in a highly elliptical orbit once every 12 hours. It will dip within 120 miles of Mercury's surface at its closest point, and go out to 9,320 miles at its farthest.

The orbit goes nearly pole-to-pole, offset by about 7 degrees. That slight tilt is to help get a handle on the planet's gravitational field, said principal investigator Sean Solomon, a planetary scientist at the Carnegie Institution of Washington, in a press conference March 15.

Measurements of the gravitational field "will tell us something about Mercury's composition, the size of the core and the structure of that core," he said.

One of the mission's main objectives is to figure out why Mercury's core is so big compared to the cores of the other rocky planets. Another is to make high-resolution maps of the whole planet, some of which has still never been seen.

"Many on the science team have been involved from the very beginning," Solomon said. "We are extremely excited to begin that mapping."

Scientists also plan to search for water ice in craters at the poles which, despite Mercury's proximity to the sun and scorching daytime temperatures, are stuck in eternal freezing shadow.

The spacecraft's seven science instruments were turned off for orbit insertion, but they will reactivate March 23. The first orbital image, planned for March 29, will include some uncharted regions near Mercury's south pole.

The science phase of the mission will begin April 4. The Messenger team will release data to the science community at six-month intervals, but will release images at least once a day throughout the mission, Solomon said.

"In addition to the global imaging we'll be doing, we've targeted more than 2,000 areas for ultra-high-res with our narrow-angle camera. Many of them were not discovered until flybys," he said. "We've got a long list."

Images: 1) Artist's conception of Messenger approaching Mercury. 2) The target area for Messenger's first image from orbit, including never-before-seen terrain. (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

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Johnald's Fantastical Daily Link Splurge

2011-03-18T13:17:00.001-07:00

Johnald's Fantastical Daily Link Splurge

Seasonal Methane Rain Discovered on Titan
Japan Quake Epicenter Was in Unexpected Location
Crop Tops: Strange Agricultural Landscapes Seen From Space

Seasonal Methane Rain Discovered on Titan

Posted: 17 Mar 2011 12:12 PM PDT

Spring may bring methane showers to the deserts of Titan, Saturn's largest moon. NASA's Cassini spacecraft recently saw a large, dark puddle appear in the wake of a storm cloud at the moon's dune-filled equator.

"It's the only easy way to explain the observations," said planetary scientist Elizabeth Turtle of Johns Hopkins University Applied Physics Laboratory, lead author of a study March 18 in Science. "We're pretty confident that it has just rained on Titan."

Aside from Earth, Titan is the only world known to have liquid lakes, clouds and a weather cycle to move moisture between them. But on chilly Titan, where temperatures plunge to -297 degrees Fahrenheit, the frigid lakes are filled with liquid methane and ethane, not water.

Titan's lakes are also exclusively confined to the poles. The moon's dry central regions are covered in rippling dunes and arid deserts.

But the dunes are crisscrossed by a network of dry channels, suggesting a wetter past. In 2006, Cassini observations showed hints of drizzle at the equator, but not enough rain to explain the riverbeds.

"So the question was, 'When was the last rainfall near the equator of Titan?'" said planetary scientist Tetsuya Tokano of the University of Cologne in Germany, who was not involved in the new work. Some researchers suggested that the rivers were a relic of a bygone era, or carved by things other than rain.

"This observation by Turtle et al. showed for the first time that there is rainfall on present Titan, not merely millions of years ago but at the present Titan," Tokano said. "This is extraordinary."

In the new study, Turtle's team describes a large cloud system moving eastward across Titan's equator on Sept. 27, 2010. By October, observations show, a dune field called Belet that lies east of the clouds suddenly darkened. The dark patch extended for more than 190,000 square miles, and started fading fast. Some spots that were dark on Oct. 14 were bright again by Oct. 29, and even more bright spots were visible on Jan. 15.

Turtle thinks the shadow is wet ground after rainfall, like a sidewalk darkened by a shower. Titan's winds aren't strong enough to wreak such sudden or vast changes, she says, and it's doubtful that the kind of explosive volcanic activity that could explain the dark patch is possible on Titan.

It's not clear how much rain fell, she adds. Some areas could have flooded or sustained small puddles, but it may just be that the surface got wet.

The showers were probably prompted by Titan's changing seasons. Cassini has been orbiting Saturn since 2004, but since a full year on Saturn — and therefore all its moons — lasts 29 Earth years, the spacecraft has only observed one 7-year season on Titan. Astronomers saw storms and rain at Titan's south pole during the summer, and then the clouds cleared after the spring equinox in August 2009.

"It's kind of the equivalent on Titan right now of early April, just into northern spring," Turtle said. "What we think triggered this huge storm is that the weather patterns are seasonal." Major cloud patterns move north as the southern summer ends, similar to the way they do on Earth, she says. The only difference is, Earth's tropics sustain rain clouds year round. On Titan, the equator may see rain only a few times a year.

The difference comes, at least in part, from Titan's leisurely rotation rate, Tokano said. Titan takes 16 Earth days to rotate once, meaning its atmospheric circulation patterns are somewhat more simple. Titan's clouds shift quickly from north to south, filling the polar lakes with rain but mostly leaving the equator out to dry.

As for whether the spring showers are good news for the possibility life on Titan, Turtle and Tokano are agnostic.

"There's no liquid water involved in any of the processes we're describing here, so life as we know it can't exist," Turtle said. "But there's clearly so much scope for prebiotic chemistry on Titan…. Understanding Titan better in general helps us to understand what the possibilities are."

Images: 1) NASA/JPL/Space Science Institute. 2) P. Huey/Science AAAS

Citation:
"Rapid and Extensive Surface Changes Near Titan's Equator: Evidence of April Showers." E.P. Turtle, J.E. Perry, A.G. Hayes, R.D. Lorenz, J.W. Barnes, A.S. McEwen, R.A. West, A.D. Del Genio, J.M. Barbara, J.I. Lunine, E.L. Schaller, T.L. Ray, R.M.C. Lopes, E.R. Stofan. Science, Vol 331, March 18, 2011. DOI: 10.1126/science.1201063.

Posted: 17 Mar 2011 09:43 AM PDT

Japan has been expecting and preparing for the "big one" for more than 30 years. But the magnitude-9.0 temblor that struck March 11 — the world's fourth biggest quake since 1900 — wasn't the catastrophe the island nation had in mind. The epicenter of the quake was about 80 miles east of the city of Sendai, in a strip of ocean crust previously thought unlikely to be capable of unleashing such energy.

"This area has a long history of earthquakes, but [the Sendai earthquake] doesn't fit the pattern," says Harold Tobin, a marine geophysicist at the University of Wisconsin-Madison. "The expectation was high for a 7.5, but that's a hundred times smaller than a 9.0."

Understanding where big earthquakes will emerge is extraordinarily difficult, and nowhere more so than Japan. The northern part of the island nation sits at the intersection of four moving pieces of the Earth's crust. Where one tectonic plate slides beneath another, forming a subduction zone, sudden slippages can unleash tremendous amounts of energy.

The Sendai earthquake occurred at the Japan Trench, the junction of the westward-moving Pacific Plate and the plate beneath northern Japan. Historical records, one of seismologists' best tools for identifying areas at risk, suggest that this segmented fault has produced several earthquakes bigger than 7.0 in the 20th century alone — but none bigger than 8.0.

That's why the Japanese government has long focused on the nation's southern coast and the northward-moving Philippine Plate, which has a proven ability to generate large quakes. Quakes larger than 8.0 tend to strike the Tokai region in central Japan every 150 years or so, with the last big one appearing in 1854.

In 1976 researcher Katsuhiko Ishibashi of Kobe University warned that Suruga trough, a subduction zone just off the coast of Tokai, was due for a big one. In the years since, the Japanese government and research community have braced for this predicted Tokai earthquake — deploying GPS systems to monitor the movements of islands on the Philippine Plate and even generating computer simulations of how crowds in train stations might behave during such an event.

Current thinking about the mechanisms that govern megaquakes also favored the Philippine Plate as the site of greatest risk. About 80 percent of all earthquakes above magnitude 8.5 occur at the edges of such geologically young, warm tectonic plates. Kilometer-thick sediment layers carried by these plates are thought to grind smooth patches that allow long stretches of fault to rupture at once. The Pacific Plate, some of the oldest ocean crust on the planet, doesn't fit this description.

But preliminary computer simulations at Harvard that crunched early data from the Sendai quake suggest that a long stretch of the Japan Trench ruptured during the event — about 390 kilometers [240 miles]. Multiple segments that usually behave independently broke over the course of two to three minutes.

"It looks like three of the segments all slipped together," says Miaki Ishii, a seismologist at Harvard. "There is some evidence that a fourth may have been involved as well." She doesn't know why these particular segments ruptured together, or why other similar segments nearby didn't join them.

What does seem to be clear is that the slip happened in a relatively shallow region of the subduction zone. According to computer simulations run by geophysicist Chen Ji at the University of California, Santa Barbara, the quake originated 8 to 20 kilometers [5 to 12 miles] below the ocean floor. The shallower an earthquake, the more easily it flexes the Earth's crust, raising a mountain of water that can turn into a tsunami. The Sendai quake lifted the seafloor several meters and generated a tsunami up to 7 meters [23 feet] high.

"We're learning that we can't discount any of these big subduction zones," says Tobin. "They're all capable of producing large earthquakes." The magnitude-9.1 earthquake that struck Sumatra in 2004 also broke the rules: It, too, happened on the edge of an old piece of crust, hurling a tsunami across the Indian Ocean that was more deadly than any in recorded history.

In the United States, seismologists are now eyeing the Cascadia fault zone that flanks Oregon and Washington, which last gave way in 1700 to produce the largest known earthquake in North American history.

"Perhaps the earthquake in Japan shouldn't have been as surprising as it was," says Stanford seismologist Greg Beroza.

Beroza explains that deposits of sand found kilometers from shore have revealed a large tsunami that struck the Sendai area during the Jogan earthquake of 869. Ever since this magnitude-8.0+ quake, the Pacific Plate has been moving more than 8 centimeters [3 inches] per year — a tectonic sprint — pushing against its neighbor plate and perhaps building a tremendous amount of strain.

Seismologists hope that the detailed Sendai earthquake data collected by Japan's advanced monitoring technologies — hundreds of sensors spaced an average of 20 to 30 kilometers [12 to 18 miles] apart across the Japanese islands — will lead to a better understanding of subduction zone quakes. Researchers will also analyze the emerging pattern of aftershocks, which now includes at least three bigger than 7.0 and dozens bigger than 6.0.

But being able to spot signs far in advance of a big earthquake — currently far beyond the reach of modern science — may require digging deeper. Tobin and his Japanese colleagues have for the first time embedded strain sensors directly inside a subduction zone, the Nankai trough located southwest of Tokai.

Large earthquakes have struck this region every 100 to 120 years, from 686 to 1946. The researchers hope to catch the next big one in the act and find a warning sign that could provide more than a minute's notice that a monster quake is on its way.

Images: The March 11 Sendai earthquake (epicenter shown as star) occurred when the westward-moving Pacific Plate took a sudden dive beneath northern Japan's plate, the identity of which is disputed among scientists. (USGS)

Posted: 17 Mar 2011 04:00 AM PDT

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Agriculture is one of the oldest and most pervasive human impacts on the planet. Estimates of the land surface affected worldwide range up to 50 percent. But while driving through the seemingly endless monotony of wheat fields in Kansas may give you some insight into the magnitude of the change to the landscape, it doesn't compare to the view from above.

When seen from space, those same boring wheat fields are transformed into a strange and even beautiful pattern. Some of the most arresting agricultural landscapes occur in the Midwestern United States in areas that rely on center-pivot irrigation (shown at right). The area pictured above near Garden City, Kansas, is being farmed to the point of resembling abstract art or a Magic Eye illusion. Groundwater from the Ogallala Aquifer is used to grow corn, wheat and sorghum in the region.

The image above, taken by the USGS' Landsat 7 satellite on Sept. 25, 2000, is a false-color composite made using data from near infrared, red and green wavelengths and sharpened with a panchromatic sensor. The red areas actually represent the greenest vegetation. Bare soil or dead vegetation ranges from white to green or brown.

The image below is a simulated true-color shot from the same county in Kansas taken June 24, 2001 by NASA's Terra satellite. Bright greens are healthy, leafy crops such as corn; sorghum would be less mature at this time of year and probably a bit paler; wheat is ready for harvest and appears a bright gold; brown fields have been recently harvested. The circles are perfectly round and measure a mile or a half mile in diameter.

In this gallery, we've collected some of the most interesting views of crops from space, including rice paddies in Thailand, cotton fields in Kazakhstan and alfalfa growing in the middle of the Libyan desert.

Images: 1) USGS/NASA. 2) USGS. 3) NASA.

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Johnald's Fantastical Daily Link Splurge

2011-03-16T13:18:00.001-07:00

Johnald's Fantastical Daily Link Splurge

Robot Nurses Are Less Weird When They Don’t Talk
Oldest Female Elephants Have Best Memory
115-Year-Old Medical X-Ray Machine Comes Back to Life
Japan Struggles to Control Quake-Damaged Nuke Plant
NASA Considers Shooting Space Junk With Lasers
Midway’s Albatrosses Survive the Tsunami

Robot Nurses Are Less Weird When They Don’t Talk

Posted: 16 Mar 2011 11:05 AM PDT

Medical patients would probably be ok with semi-autonomous robots tending to them, but only if the robots don't talk to them first.

Robotics researchers tested whether a verbal explanation from a robot would help people feel more comfortable with the robot administering care, but found that precisely the opposite was true.

"Robotics has mostly been about teaching machines how to not touch people, walls, chairs and other objects," said robotics researcher Tiffany Chen of the Georgia Institute of Technology, part of a team that presented the study March 9 at a human-robot interaction conference in Switzerland. "This is one of the first steps toward understanding what happens when robots touch people."

Most semi-autonomous robots do precise or dangerous grunt work, such as assemble automobiles or help neutralize improvised bombs. Now robots have advanced to the point that they are ready to take on more delicate work, such as assisting nurses. But the bots may not be as accepted in a hospital as they are in a factory.

"If we want robots to be successful at health care, we're going to need to think about how do we make those robots communicate their intention and how do people interpret the intentions of the robots," biomedical engineer Charlie Kemp of the Georgia Institute of Technology said in a video about the work.

Kemp and his team programmed a robot named Cody to gently wipe its hand across volunteers' arms, as if cleaning them, or administer a soothing touch. In some trials, Cody explained to people with a synthetic female voice what it was about to do, and in others it didn't say anything until after touching the participants.

People generally didn't mind being touched by Cody overall, but were less comfortable with the robot when it spoke to them beforehand. And participants were more accepting of a potentially necessary medical touch than an attempt at a soothing touch by the robot.

"The results of the voice timing surprised us. We thought people would want to be told something like 'I'm going to clean you,' and then the robot cleans. But the opposite was true," Chen said.

Image: Cody the robot touches one of 56 study participants. (Georgia Tech)

Posted: 16 Mar 2011 10:00 AM PDT

Not to cause dinner table shouting or new excesses of political punditry — but in a test of a particular leadership skill among elephants, age and experience really did trump youth and beauty.

Elephant matriarchs 60 years of age or older tended to assess threats in a simulated crisis more accurately than younger matriarchs did, says Karen McComb of the University of Sussex in Brighton, England. When researchers played recordings of various lion roars, elephant groups with older matriarchs grew especially defensive at the sound of male cats. Younger matriarchs' families underreacted, McComb and her colleagues report in an upcoming Proceedings of the Royal Society of London B.

The older females have it right, McComb says. Male lions rarely attack an elephant, but when they do, they can be especially deadly: A single male can bring down an elephant calf.

Studying leadership among animals has become an active research area. "People have become intrigued by some of the parallels between the sorts of characteristics that seem to define a leader in animals and in humans," McComb says.

The new elephant approach "is definitely novel," says psychologist Mark van Vugt of VU University Amsterdam, who studies the evolution of leadership. The new paper extends a general observation — that older individuals show more leadership in tasks involving specialized knowledge — into situations involving threats.

"There is an interesting trade-off here, which certainly applies to humans and maybe elephants as well," van Vugt says. "The group might want a young, fit and aggressive leader to defend the group — the Schwarzenegger type — but at the same time might want an older, more experienced leader — the Merkel type — to make an accurate assessment of the dangers in the situation."

Among elephants, family groups made up of a matriarch and a dozen or so of her female kin and their youngsters can stay together for decades. The oldest elephant provides leadership, but "she doesn't lead by being heavy-handed," McComb says. She may not walk at the front of the group when they commute to their morning waterhole, but the other elephants pay attention to where she goes and how she reacts.

To test for crisis leadership among elephants, McComb and her colleagues played lion calls to 39 elephant families in Kenya's Amboseli National Park. Researchers compared reactions to roars from one lion versus three lions. All the matriarchs correctly perceived that three was more worrisome than one. "It was quite a revelation" says coauthor Graeme Shannon cq, also of Sussex. Before this test, evidence had been unclear about how widespread numerical threat assessment would be. The older matriarchs managed another layer of awareness though, by judging male lions more threatening than females.

"If you remove these older individuals, you're going to have a much bigger impact than you realize because they're repositories of ecological knowledge and also of social knowledge," McComb says. Poachers, targeting the big old elephants, pose a particular menace to the species.

Image: Graeme Shannon

Video: Elephants react to what they perceive as a very dangerous lion during a test of threat assessment. (Karen McComb/Vimeo)

Posted: 16 Mar 2011 09:02 AM PDT

A team of physicists, engineers and radiologists recently revived a first-generation X-ray device that had been collecting dust in a Dutch warehouse. The antique machine still sparked and glowed like a prop in an old science fiction movie, and used thousands of times more radiation than its modern counterparts to make an image.

The old machine was originally built in 1896 by two scientists in Maastricht, the Netherlands, just weeks after German physicist Wilhelm Conrad Röntgen reported his discovery of X-rays — an achievement that won him the first-ever Nobel Prize in physics and sparked a rash of copycat experiments.

H.J. Hoffmans, a physicist and high school director in Maastricht, and L. Th. van Kleef, director of a local hospital, assembled the system from equipment already on hand at Hoffmans' high school and used it to take some of the first photographs of human bones through the skin, including in van Kleef's 21-year-old daughter's hand.

Since then, X-rays, which are the right wavelength to tunnel through muscle but are slowed by denser bones, have become almost synonymous with medical imaging. But most of those first X-ray systems were lost to history. Because the techniques and technology to measure radiation doses weren't invented until decades after the first X-ray machines came about, no one knows exactly how powerful those systems were.

"There's a gap in knowledge with respect to these old machines," said medical physicist Gerrit Kemerink of the Maastricht University Medical Center. "By the time they could measure the properties, these machines were long gone."

About a year ago, when Kemerink's colleague at the hospital dug Hoffmans and van Kleef's aging machine out of storage to use in a local TV program on the history of health care in the region, Kemerink grew curious about what the gadget could do. In a paper published online in Radiology, Kemerink reports the first-ever diagnostics on a first generation X-ray device.

"I decided to try to do some measurements on this equipment, because nobody ever did," he said.

Aside from a modern car battery and some wires, the researchers used only the original equipment, including an iron cylinder wrapped in wire to transfer electrical energy from one circuit to another and a glass bulb with metal electrodes at each end.

The glass bulb, technically called a Crookes tube, contained a tiny bit of air, about a millionth of normal air pressure. When the researchers placed a high voltage over the tube, the electrons in the gas were ripped from their atoms and zipped across the tube from one electrode to the other.

Electrons naturally emit X-rays when they speed up, slow down or change direction. When the electrons hit the glass walls of the Crookes tube, they came to a screeching halt, giving off a ghostly green glow and invisible X-rays.

An 1896 Crookes tube emitting X-rays.

The machine took some coaxing before it would glow, Kemerink said. The team fiddled with it for a solid half hour with no success.

"At the time we were thinking that it would be possible that we would not succeed with our plans," he said. "But then suddenly something happened, and we were in business."

Kemerink now thinks that the gas pressure inside the bulb was too high for the electrons to travel through the tube. But then a bit of aluminum on one of the electrodes melted, sucking gases from inside the bulb.

"It's a technique used today to improve your vacuum: Evaporate metal and trap some gases," he said. "That is what happened, although we did not do it on purpose."

Images of a hand specimen from an 86-year-old woman taken with the old X-ray machine (left) and a modern one (right). The exposure for the 1896 system took 21 minutes.

The researchers used standard hospital radiation-detecting devices to measure the amount of X-rays needed to take an image of the bones in a human hand (this time, a specimen borrowed from the anatomy department, not from a living person). The old machine took surprisingly clear pictures, but gave the skin a dose of radiation 1,500 times greater than the same image would require today. An exposure that takes 21 milliseconds (thousandths of a second) on a modern machine took up to 90 minutes on the antique system.

"It was interesting that the image quality was actually that good," said radiologist Tom Beck of Quantum Medical Metrics, a company that researches ways to get structural information from bones using medical imaging. "That was surprising."

This first-generation system did not produce enough radiation to cause health problems, although Kemerink and colleagues all stood behind a transparent lead shield whenever the machine was on, just in case. But X-ray devices got steadily more powerful shortly after Hoffmans and van Kleef built their machine, and technicians didn't always take precautions against harmful radiation.

"Within weeks, people reported skin burns, a little bit later even much worse things," like blisters and sores that wouldn't heal, Kemerink said. Some workers had to have fingers or even a whole arm amputated. "Many of these early X-ray workers developed cancer, and many of them died untimely, very young."

The difference in danger highlights how far X-rays have come, he said. In another study published online Feb. 15 in Insights into Imaging, Kemerink and colleagues showed that, with all the shielding used today, modern X-ray workers feel less radiation in the hospital than they do at home.

"There's so much to say about how far we've come," Kemerink said. "These machines when they started they were extremely dangerous. Now in all those years, they improved technology so far that you can really neglect what you are receiving when you do normal X-ray scans."

Working with the machine was "very special, I must say," Kemerink added. The air smelled of ozone, the interruptor buzzed, lightning crackled in the spark gap, and the insides of the human body showed themselves.

"Our experience with this machine," the researchers wrote, "was, even today, little less than magical."

Video: Maastricht University Medical Center. Images: Courtesy Gerrit Kemerink.

Citations:
"Characteristics of a First-Generation X-Ray System." Martijn Kemerink, Tom J. Dierichs, Julien Dierichs, Hubert J.M. Huynen, Joachim E. Wildberger, Jos M.A. van Engelshoven, Gerrit J. Kemerink. Radiology, online March 16, 2011. DOI: 10.1148/radiol.11101899.
"Less radiation in a radiology department than at home." Gerrit J. Kemerink, Marij J. Frantzen, Peter de Jong and Joachim E. Wildberger. Insights into Imaging, online Feb. 15, 2011. DOI: 10.1007/s13244-011-0074-7

Posted: 15 Mar 2011 10:08 AM PDT

In the aftermath of the earthquake and tsunami that struck northeastern Japan on March 11, engineers are flooding three nuclear reactors with seawater in an effort to cool their radioactive cores and to prevent all their nuclear fuel from melting down. Explosions have been recorded at two of the reactors, but do not seem to have breached the crucial inner containment vessels.

The grimmest situation is at the final reactor, where water stopped flowing temporarily March 14, exposing the fuel rather than cooling it. Much now depends on the containment vessels that shield the highly radioactive reactor cores. Even a full meltdown does not necessarily mean that the reactors will release large amounts of radioactive material — as long as the vessels remain intact.

Officials are closely monitoring several reactors at the Fukushima facility, on the northeastern coast of Japan near where the magnitude-8.9 earthquake hit. There are two clusters of reactors at Fukushima. The Daiichi cluster includes six boiling-water reactors, all of which came online in the 1970s.

In the boiling-water design, nuclear reactions in the core generate heat and cause water to boil, which makes steam to drive turbines and produce electricity. Together, the six Daiichi reactors produced 4.7 gigawatts of power before the accident.

The largest nuclear facility in the United States, the Palo Verde facility in Arizona, has a capacity of 3.7 gigawatts and serves roughly 4 million people. With 54 nuclear facilities operating before the accident, Japan is the third-largest producer of nuclear energy after France and the United States.

Most nuclear reactors use uranium as their primary fuel, although Unit 3 at Daiichi uses a mix that includes plutonium. Pellets of enriched fuel are encased inside long, narrow tubes made of an alloy containing the metal zirconium. These tubes, known as fuel rods, are spaced in an array with water flowing between them. Several hundred of these packages are then put together to create the core of the nuclear reactor.

The uranium-235 isotope, which contains 92 protons and 143 neutrons, is inherently unstable, tending to split (or fission) into lighter elements. Such spontaneous fission releases stray neutrons. When one of those neutrons hits a uranium atom, it also initiates fission into lighter elements, releasing more neutrons. Those neutrons can then go on to hit other uranium atoms in the fuel pellets, causing a chain reaction.

A reactor is said to have "gone critical" when it has this self-sustaining reaction underway in its core. As long as operators keep variables such as temperature and the flux of neutrons in hand, the fission will continue at a controlled pace.

But the reactor core requires water to cool things down and moderate the flux of neutrons coming from the fissioning uranium. Without water things can heat up quickly — both the temperature and the rate of fission within the reactor core.

According to Japan's Nuclear and Industrial Safety Agency, the earthquake knocked out power to the Daiichi facility. "Control rods" to slow the rate of fissioning dropped automatically in between the fuel rods.

Control rods are usually attached to magnets and hang above the core, and if an earthquake strikes they automatically detach, drop down and help shutter the reaction, says Ron Hart, a retired professor of nuclear engineering from Texas A&M University in College Station. The control rods absorb neutrons to prevent the reaction with uranium that causes fission. But even with the control rods in place, the reactor still produces heat at a small fraction of its full power, because of the decay products of the uranium fission.

As planned, backup diesel generators kicked in after the monster earthquake and continued to pump water in to cool the reactor cores. But when a tsunami swept across the Japanese coast about an hour later, the wave disabled the backup generators. The next backup system then kicked in: battery-powered pumps.

But the battery pumps could not keep up with the residual heat still coming from the cores of several Daiichi reactors. Excess heat caused steam to build up in the system, which operators eventually vented into the environment along with low levels of radioactive elements like cesium and iodine.

At the same time, though, hydrogen gas had apparently built up within the core, likely created by chemical reactions of the hot zirconium rods with water. The explosions at Daiichi Units 1 and 3 were likely caused by that hydrogen igniting.

Potentially far more serious is Unit 2, where pumps failed for a time on March 14, causing the water level to expose the fuel rods almost completely. If the rods melt entirely, they could drop their fuel pellets to the bottom of the reactor core. The pellets could then generate enough heat to melt through the bottom of the steel containment vessel.

"Once that happens the ability to contain the accident is greatly reduced, because the core is liquefied and spreads across the floor," says Edwin Lyman, a physicist with the Union of Concerned Scientists in Washington, D.C., a group that has long voiced concerns about the risks of nuclear power.

In the 1986 nuclear accident at Chernobyl in Ukraine, the melting core did not have the heavy shielding of a containment vessel, as the reactors in Japan do. The Chernobyl core exploded, blowing radioactive materials over large parts of western Asia and Europe and causing an ecological and public health castastrophe.

In the 1979 Three Mile Island accident in Pennsylvania, the reactor's core suffered a partial meltdown but its pressure vessel was not breached, and only low levels of radioactive material made it into the environment. The Daiichi incidents, at least so far, may be far more like Three Mile Island than like Chernobyl.

On the international scale used by experts to rank nuclear incidents, Chernobyl ranked as a "major accident" or 7, the highest on the scale. Three Mile Island was a 5, an "accident with wider consequences." Japanese officials have said they regard the Fukushima incident as a 4, an "accident with local consequences."

Operators at Daiichi have flooded all three reactors with seawater mixed with boric acid. The boron in the boric acid absorbs neutrons and helps keep them from bouncing around and triggering further fission in the fuel rods. Salts in the seawater will, however, permanently corrode the reactor cores and render them unusable in the future.

Hart says it will probably take several weeks of keeping the cores underwater to cool them enough to stop the fission completely. At that point, operators can carefully extract the cores and take them to a containment facility to assess damage, take them apart and dispose of them.

Image: DigitalGlobe [high-resolution version]

Posted: 15 Mar 2011 09:32 AM PDT

The growing cloud of space junk surrounding the Earth is a hazard to spaceflight, and will only get worse as large pieces of debris collide and fragment. NASA space scientists have hit on a new way to manage the mess: Use mid-powered lasers to nudge space junk off collision courses.

The U.S. military currently tracks about 20,000 pieces of junk in low-Earth orbit, most of which are discarded bits of spacecraft or debris from collisions in orbit.

The atmosphere naturally drags a portion of this refuse down to Earth every year. But in 1978, NASA astronomer Don Kessler predicted a doomsday scenario: As collisions drive up the debris, we'll hit a point where the amount of trash is growing faster than it can fall out of the sky. The Earth will end up with a permanent junk belt that could make space too dangerous to fly in, a situation now called "Kessler syndrome."

Low-Earth orbit has already seen some scary smashes and near-misses, including the collision of two communications satellites in 2009. Fragments from that collision nearly hit the International Space Station a few months later. Some models found that the runaway Kessler syndrome is probably already underway at certain orbit elevations.

"There's not a lot of argument that this is going to screw us if we don't do something," said NASA engineer Creon Levit. "Right now it's at the tipping point … and it just keeps getting worse."

In a paper submitted to Advances in Space Research and posted to the preprint server arXiv.org, a team led by NASA space scientist James Mason suggests a novel way to cope: Instead of dragging space junk down to Earth, just make sure the collisions stop.

"If you stop that cascade, the beauty of that is that natural atmospheric drag can take its natural course and start taking things down," said William Marshall, a space scientist at NASA and coauthor of the new study. "It gives the environment an opportunity to clean itself up."

Simply keeping new fragments from forming can make a big difference for orbital safety, Levit said. Because objects with more surface area feel more drag, the atmosphere pulls down the lightest, flattest fragments of space junk first. When big pieces of debris break up into smaller ones, the pieces become harder and harder to remove.

Worse, the pieces left behind are often the most dangerous: small, dense things like bolts.

"If one collides with a satellite or another piece of debris at the not-unreasonable relative velocity of, say 5 miles per second, it will blow it to smithereens," Levit said.

In the new study, the researchers suggest focusing a mid-powered laser through a telescope to shine on pieces of orbital debris that look like they're on a collision course. Each photon of laser light carries a tiny amount of momentum. Together, all the photons in the beam can nudge an object in space and slow it down by about .04 inches per second.

Shining the laser on bits of space litter for an hour or two a day should be enough to move the whole object by about 650 feet per day, the researchers show. That might not be enough to pull the object out of orbit altogether, but preliminary simulations suggest it could be enough to avoid more than half of all debris collisions.

NASA scientists have suggested shooting space junk with lasers before. But earlier plans relied on military-class lasers that would either destroy an object altogether, or vaporize part of its surface and create little plasma plumes that would rocket the piece of litter away. Those lasers would be prohibitively expensive, the team says, not to mention make other space-faring nations nervous about what exactly that military-grade laser is pointing at.

The laser to be used in the new system is the kind used for welding and cutting in car factories and other industrial processes. They're commercially available for about $0.8 million. The rest of the system could cost between a few and a few tens of millions of dollars, depending on whether the researchers build it from scratch or modify an existing telescope, perhaps a telescope at the Air Force Maui Optical Station in Hawaii or at Mt. Stromlo in Australia.

"This system solves technological problems, makes them cheaper, and makes it less of a threat that these will be used for nefarious things," said space security expert Brian Weeden, a technical adviser for the Secure World Foundation who was not involved in the new study. "It's certainly very interesting."

However, "I don't think this is a long-term solution," Weeden said. "It might be useful to buy some time. But I don't think it would replace the need to remove debris, or stop creating new junk."

Don Kessler, from whom the Kessler syndrome takes its name, agrees, and points out that laser light isn't forceful enough to divert the biggest pieces of junk.

"The only complete solution to is to prevent collisions involving the most massive objects in Earth orbit," he said.

Image: ESA

Citation:
"Orbital Debris-Debris Collision Avoidance." James Mason, Jan Stupl, William Marshall and Creon Levit. Submitted to Advances in Space Research.

Posted: 15 Mar 2011 08:58 AM PDT

The famed albatrosses of Midway Atoll took a beating from the tsunami, but their population will survive, say biologists on the islands.

There are, of course, more pressing concerns in the tsunami's aftermath than wildlife, and some might balk at paying attention to birds right now. But compassion isn't a zero-sum game, and Midway Atoll is one of Earth's natural treasures: 2.4 square miles of coral ringing a deep-sea mountaintop halfway between Honolulu and Tokyo, a flyspeck of dry land that's home to several million seabirds.

Roughly two-thirds of all Laysan albatrosses live on Midway's two islands, as do one-third of all black-footed albatrosses, and about 60 people. Many of them work at the Midway Atoll National Wildlife Refuge. They had time to prepare for the tsunami, which struck late on the night of March 10. Nobody was hurt; after the waves receded, they checked on the wildlife.

An estimated 1,000 Laysan adults were killed, and tens of thousands of chicks, said Refuge official Barry Stieglitz. Those figures represent just the first wave of mortality, as adults who were at sea when the tsunami hit may be unable to find their young on returning. Chicks now wandering on shore may be doomed — but in the long run, the population as a whole will recover.

"The loss of all these chicks is horrible. It's going to represent a significant portion of this year's Laysan albatross hatch. But in terms of overall population health, the most important animals are the proven, breeding adults," said Stieglitz. "In the long term, the greatest impact would be if we lost more adults. The population should come through this just fine."

On a sadder note, however, one of the wandering chicks is the first short-tailed albatross to hatch on Midway in decades. The species was hunted to near-extinction in the 19th century, its feathers so fashionable that a population of millions was reduced to a handful of juveniles who stayed at sea during the carnage. (Young short-tailed albatrosses live in the open ocean for several years before mating.) About 3,000 of the species now survive, and a few have recently made a home on Midway.

"If the chick lost one parent, it could be in danger. If it lost both, it's definitely out of luck," Stieglitz said.

Another well-known avian denizen of Midway is Wisdom, a 60-year-old female Laysan albatross. Banded for identification in 1956, Wisdom is the oldest known wild bird. In February, she was spotted rearing a new chick.

"When I gaze at Wisdom, I feel as though I've entered a time machine," wrote U.S. Fish and Wildlife Service biologist John Klavitter in an email. "My mind races to the past and all the history she has observed through time."

Midway's Laysan albatrosses feed in waters off Alaska, flying about 50,000 miles each year as adults. Wisdom has flown between 2 and 3 million miles in her lifetime, compensating for age with smarts and efficiency. She hasn't been spotted since the tsunami, but Stieglitz said the biologists haven't looked for her yet. Wisdom's nest is on high ground. They're not too worried about her.

See Also:

Images: 1) Short-tailed albatross chick./Pete Leary, USFWS. 2) Wisdom, the 60-year-old Laysan albatross./John Klavitter, USFWS.

Johnald's Fantastical Daily Link Splurge

2011-03-15T13:41:00.001-07:00

Johnald's Fantastical Daily Link Splurge

Camera Traps Reveal Secret Animal Worlds
North America Safe From Radioactive Particles
Sperm Whales May Have Names

Camera Traps Reveal Secret Animal Worlds

Posted: 15 Mar 2011 04:00 AM PDT

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Asian black bear, November 2008, China. [high-resolution version]

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Catching images of wild animals, especially rare ones, can be exceedingly difficult for photographers. But the Smithsonian Institution recently released more than 200,000 wildlife images captured by automated cameras hidden in forests, mountains and savannas across the globe.

Called Smithsonian Wild, the project harbors five years' worth of photographs collected in seven countries by dozens of camera traps that take photos when animals wander nearby. Some are equipped with night vision, strobe flashes and other gizmos, and some can record video.

"Each camera-trap image is a record of an animal in space and time, a record of life on Earth. To my knowledge, this is the largest database of such photos in existence," said the Smithsonian's Robert Costello, co-leader of the project. "If you create a research-grade repository that's safe and secure, it's going to be useful to researchers for a long, long time."

The scent of one person can spook shy creatures for miles around, which is when camera traps come in handy. The devices take pictures only when an animal's heat signature is detected by sensors inside a weatherproof housing. Hunters have popularized camera traps to better track and map game, but scientists use them to observe secretive animal behaviors, estimate at-risk wildlife populations and even rediscover species once thought to be extinct.

"Many animals leave virtually no sign of their existence, so camera traps are just a godsend for people like me," said wildlife ecologist William McShea of the Smithsonian Institution, co-leader of the project. "It's much better than looking at a handful of feces and wondering what dropped it. These images are like museum-quality specimens with collection dates, locations, species names and other veracious metadata."

The $29,000 pilot project used only a portion of more than a million camera-trap photos available to the Smithsonian. Costello, McShea and others hope to launch a new version that incorporates older camera-trap images and has features hat will make it easier for scientists to use and upload data. The team also wants to enlist the public's help in deploying camera traps, which cost anywhere between $200 and $600 each.

"These cameras aren't rocket science. I can train anyone to use them in under two hours, even kids," McShea said. "I'd love to have school systems deploying these in Montana, Indiana and other regions, then uploading that stuff to our database."

Aside from bolstering future research, McShea said the database is an engrossing way to learn about animals in their natural environments.

"Pictures of wild animals are usually very majestic, showing them regally, off in the distance. But camera traps bring out the good, the bad and the ugly," he said. "You can see them scratching their privates, being bit by vampire bats and even mating. It's not what you'd expect, and it makes their existence more real to me."

Te gallery above shows off some of the collection's best images and videos.

Images: Smithsonian Wild/Smithsonian Conservation Biology Institute.

Videos: Blue Raster/Smithsonian Wild/Smithsonian Conservation Biology Institute

Posted: 14 Mar 2011 10:29 AM PDT

Radioactive particles from the failing Fukushima Daiichi nuclear power station pose little immediate risk to North America, and should fall into the Pacific before reaching western shores.

Using a publicly available modeling system for airborne pollutants developed by the National Oceanic and Atmospheric Administration, Weather Underground's Jeff Masters has modeled the spread of radioactive plumes. So far, the "great majority of these runs" have seen the plumes float over the Pacific, reaching eastern Siberia and the western coast of North America in about a week.

"Such a long time spent over water will mean that the vast majority of the radioactive particles will settle out of the atmosphere or get caught up in precipitation and rained out," wrote Masters. "It is highly unlikely that any radiation capable of causing harm to people will be left in the atmosphere after seven days and 2000-plus miles of travel distance."

A press release issued March 13 by the U.S. Nuclear Regulatory Commission echoed Masters' speculation. "Given the thousands of miles between the two countries, Hawaii, Alaska, the U.S. Territories and the U.S. West Coast are not expected to experience any harmful levels of radioactivity," (pdf) they announced.

The March 11 earthquake disrupted cooling systems that pump fresh water onto fuel rods inside the plant's reactors. Even when reactors are shut down, the rods continue to produce heat. Without cooling, the rods could melt, releasing radioactive steam inside. (See Nature.com's Great Beyond blog for an excellent anatomy of the disaster.)

Repair crews are now using fire pumps to flood the plant's reactors with seawater. It's a touch-and-go process, however, and steam buildup produced explosions on Saturday and again Monday morning. A partial meltdown is now taking place. A full meltdown is possible but unlikely. In the meantime, steam from the reactors will send radioactive particles airborne.

According to the Pentagon, soldiers aboard the aircraft carrier Ronald Reagan, now sailing the Pacific, were exposed to a month's worth of radiation in one hour from particles blown out to sea. Winds over Japan blew east across the Pacific last week, and are expected to do so for the next week.

Masters noted that the Chernobyl disaster failed to spread "significant contamination" beyond 1,000 miles, and that disaster was far worse than Fukushima Daiichi has been. This release could, however, continue for months, until the fuel rods have completely spent themselves.

Image: Atmospheric simulation for radioactive particles released March 11. The blue represents particles released about 300 feet into the air, and red about 1,000 feet. The black star is the location of the Fukushima Daiichi plant./Jeff Masters and NOAA.

See Also:

Sperm Whales May Have Names

Posted: 14 Mar 2011 05:00 AM PDT

Subtle variations in sperm-whale calls suggest that individuals announce themselves with discrete personal identifier. To put it another way, they might have names.

The findings are preliminary, based on observations of just three whales, so talk of names is still speculation. But "it's very suggestive," said biologist Luke Rendell of Scotland's University of St. Andrews. "They seem to make that coda in a way that's individually distinctive."

Rendell and his collaborators, including biologists Hal Whitehead, Shane Gero and Tyler Schulz, have for years studied the click sequences, or codas, used by sperm whales to communicate across miles of deep ocean. In a study published last June in Marine Mammal Sciences, they described a sound-analysis technique that linked recorded codas to individual members of a whale family living in the Caribbean.

In that study, they focused on a coda made only by Caribbean sperm whales. It appears to signify group membership. In the latest study, published Feb. 10 in Animal Behavior, they analyzed a coda made by sperm whales around the world. Called 5R, it's composed of five consecutive clicks, and superficially appears to be identical in each whale. Analyzed closely, however, variations in click timing emerge. Each of the researchers' whales had its own personal 5R riff.

'This is just the first glimpse of what might be going on.'

The differences were significant. The sonic variations that were used to distinguish between individuals in the earlier study depended on a listener's physical relationship to the caller: "If you record the animal from the side, you get a different structure than dead ahead or behind," said Rendell. But these 5R variations held true regardless of listener position.

"In terms of information transfer, the timing of the clicks is much less susceptible" to interference, said Rendell. "There is no doubt in my mind that the animals can tell the difference between the timing of individuals." Moreover, 5R tends to be made at the beginning of each coda string as if, like old-time telegraph operators clicking out a call sign, they were identifying themselves. Said Rendell, "It may function to let the animals know which individual is vocalizing."

Audio: From a 2008 study of overlapping codas in pairs of sperm whales. One animal produces 1+1+3, the apparent group-level identifier. Both then produce overlapping 4R codas. After that, the first whale continues with 4R, while the other switches to 1+1+3. Finally, both make 1+1+3. The full meaning of such exchanges remains unclear, but they appear to reinforce social bonding.

Rendell stressed that much more research is needed to be sure of 5R's function. "We could have just observed a freak occurrence," he said. Future research will involve more recordings. "This is just the first glimpse of what might be going on."

That individual whales would have means of identifying themselves does, however, make sense. Dolphins have already been shown to have individual, identifying whistles. Like them, sperm whales are highly social animals who maintain complex relationships over long distances, coordinating hunts and cooperating to raise one another's calves.

Sperm-whale coda repertoires can contain dozens of different calls, which vary in use among families and regions, as do patterns of behavior. At a neurological level, their brains display many of the features associated in humans with sophisticated cognition. Many researchers think that sperm whales and other cetacean species should be considered "non-human persons," comparable at least to chimpanzees and other great apes.

Compared to primates, however, studying the behaviors and relationships of whales is extremely difficult. They don't take well to aquariums, and observations in the wild take place on their aquatic terms.

What's been observed so far are just "the crude behavioral measures we get by following them in a boat," said Rendell. "I'd argue that there is probably a vast amount of complexity out there in sperm whale society that we have yet to understand. As we get to know more about them, we're going to continue to reveal complexities that we didn't anticipate."

Image: NOAA. Audio: Luke Rendell.

See Also:

Citation: "Individually distinctive acoustic features in sperm whale codas." By Ricardo Antunes, Tyler Schulz, Shane Gero, Hal Whitehead, Jonathan Gordon, Luke Rendell. Animal Behavior, Feb. 10, 2011.

Johnald's Fantastical Daily Link Splurge

2011-03-13T14:24:00.001-07:00

Johnald's Fantastical Daily Link Splurge

The Tsunami’s Ripple Effect
Space Duct Tape Could Confuse Mars Rover
Turn Your Cellphone Into a High-Powered Scientific Microscope
Earthquake Is Biggest in Japan’s Recorded History
Laser-Powered Tractor Beam Could Move Tiny Particles
GOP Assault on Environment Defeated — For Now
Best Mars Images From Orbiter’s First 5 Years

The Tsunami’s Ripple Effect

Posted: 12 Mar 2011 12:27 PM PST

I'm in southern South America preparing to lead a geological field trip and am just now catching up on the huge earthquake in Japan, the subsequent tsunami, and news about the devastation. My thoughts are with all the people directly affected by this disaster. There's obviously a lot of news out there to read about this event. Many of the geoscience bloggers are covering the geological aspects of this event — I don't have the time on this slow wi-fi connection to summarize it all so here are just a few:

Chris Rowan of Highly Allochthonous discusses the tectonic context of the earthquake
Callan Bentley of Mountain Beltway highlights an interactive map of the event
Susan W. Kieffer of Geology in Motion compiles some links to video footage
Elli Goeke of Life in Plane Light also has a nice collection of links

Me and a couple colleagues have been down in this region for a few days checking out the outcrops and talking with locals to prepare for the trip. The participants are all arriving today and flying into the city of Punta Arenas, Chile, along the coast on the Strait of Magellan, which is where I sit right now. Earlier today there was talk of tsunami warning and potential evacuations but this has since been lifted. I don't know the details but am assuming a 'better safe than sorry' precaution was behind the alert. I'm all for that. I have no time for those who get upset about authorities "crying wolf" when it comes to this stuff.

What's amazing — and quite scary — is how much of the planet is affected by an event like this. Here I am at the southern tip of South America, more than 10,000 miles from the earthquake's epicenter, and we had to keep an eye on what was going on. Incredible.

Space Duct Tape Could Confuse Mars Rover

Posted: 11 Mar 2011 02:02 PM PST

The NASA equivalent of duct tape could leak enough methane to confuse the next Mars rover's life-detecting sensors.

Astrobiologists found evidence for three distinct plumes of methane flowing from beneath the planet's surface, like swamp gas or a burp, in January 2009. The gas could simply mean that Mars is more geologically active than previously thought. But because much of Earth's methane is a byproduct of life, the plumes could point to something living, eating or breathing methane beneath the Martian surface.

To settle the question of the methane's origin, the next Mars rover, called Mars Science Laboratory or Curiosity, will launch in late 2011 equipped with a suite of instruments capable of sniffing out one molecule of methane in a billion other molecules.

But some of the materials in the rover itself could also release methane and confuse the sensors. In a paper in press in the journal Icarus, microbiologist and veteran Mars simulator Andrew Schuerger of the University of Florida and colleagues show that the tape used to hold the rover's joints together could release enough methane to be a problem.

"I think it's a valid concern,"said planetary scientist Adam Johnson of Indiana University, who has investigated which Earth microbes could hitchhike to Mars but was not involved in the new work. "We're sending a very very sensitive instrument, and we are able to produce concentrations of methane that are orders of magnitude above the detection limits for that instrument."

Schuerger and colleagues placed 18 materials in the Mars Simulation Chamber, a stainless steel cylinder whose interior mimics the atmosphere, dustiness, sunlight, temperature and pressure at the Martian surface.

"Andrew's simulation setup in his chamber is state of the art, the best simulation chamber in the world," Johnson said. "As far as simulation of the Mars conditions, you can't ask for much better."

The researchers tested a variety of biological materials, including amino acids, DNA and spores of a common soil-dwelling bacterium. They also checked several materials used to build the rover itself, including vacuum grease, a small sundial like the one rovers Spirit and Opportunity use to calibrate colored images, and kapton tape, the space industry equivalent of duct tape.

"I kind of think of it as electrical tape on Mars," Johnson said. "It's used for everything on there."

After eight hours in the chamber, all the organic materials tested emitted some amount of methane, though not enough to worry about in most cases. The methane comes from the interaction of sunlight with materials that contain a methyl group, one carbon atom attached to three hydrogen atoms. Ultraviolet radiation from the sun (or, in the simulation chamber, a special lamp) could rip methyl groups from the materials. The charged methyl groups could then steal an extra hydrogen atom from a neighboring molecule to form stable molecules of methane, which has one carbon and four hydrogens.

Surprisingly, the bacterial spores they tested leaked noticeable amounts of methane, even after they had been irradiated to death. But the standards for cleaning the rover before launch are so stringent that there probably won't be enough spores left on the rover by launch time to pose much of a problem.

The most trouble could come from kapton tape, which is ubiquitous and unavoidable on the rover. Schuerger's team found that in the first few Martian days of the mission, the sensors in Curiosity's Tunable Laser Spectrometer could pick up a few tens of methane molecules per million other molecules, about 100 times above the instrument's detection limits.

This is especially worrisome given that Curiosity uses about 3 square meters of kapton tape, more than any previous rover.

"It's a big monster rover," said NASA planetary scientist Paul Mahaffy, who is in charge of MSL's Sample Analysis at Mars (SAM) instrument. "They use the appropriate level of tape to secure that stuff down. There's just more of it than there might have been on [Spirit and Opportunity]."

The rover team already has a few low-tech solutions in mind to find the true Martian methane, Mahaffy said. First, they'll take measurements at night, when ultraviolet radiation will be at a low.

"My best guess is, once you rotate into the dark, methane production stops pretty fast," Mahaffy said. "By sampling at night we'd get a much cleaner sniff of the Martian atmosphere."

The rover will also rotate the sensors into the wind to get the strongest whiff of the Martian atmosphere. Schuerger and colleagues suggest coming up with more detailed models of how much methane kapton tape will produce, and where on the rover it's likely to show up. They also note that kapton tape gives off less and less methane as time goes on, so methane detections in the later parts of the mission should be more reliable.

"By no means does is nullify the measurement we're trying to do on [Mars Science Laboratory]," Mahaffy said.

Still, the study is "very useful," Mahaffy said. "It will help us do a better job of sorting out what's really there on Mars, and what we might bring along from Earth. The last thing we want to do is have a false positive."

Images: 1. Engineers assemble the Mars Science Laboratory ("Curiosity"), using rolls of shiny kapton tape. (NASA/JPL-Caltech) 2. The Mars Simulation Chamber. (Schuerger et al./Icarus)

Citation:
"Methane Evolution from UV-irradiated Spacecraft Materials under Simulated Martian Conditions: Implications for the Mars Science Laboratory (MSL) Mission." Andrew C. Schuerger, Christian Clausen, Daniel Britt. Icarus, in press, 2011.

Posted: 11 Mar 2011 10:14 AM PST

Using tape, rubber and a tiny glass ball, researchers transformed an iPhone into a cheap, yet powerful microscope able to image tiny blood cells. They've also added a clinical-grade cellphone spectroscope that might be able to measure some vital signs.

And with a few dollars and some patience, you can do the same to your own phone. (See instructions below.)

"It still amazes me how you can build near-research-grade instruments with cheap consumer electronics," said physicist Sebastian Wachsmann-Hogiu of the University of California at Davis, leader of a study March 2 in PLoS ONE. "And with cellphones, you can record and transmit data anywhere. In rural or remote areas, you could get a diagnosis from a professional pathologist halfway around the world."

Similar laboratory devices can cost thousands of dollars and be extremely bulky. Other researchers have created cellphone laboratory kits, but this new microscope is the most compact, simple and inexpensive design created so far. The team's other new device — a light-splitting spectrometer — looks crude but may have high enough resolution to measure blood oxygen levels, for example.

Electrical engineer Aydogan Ozcan of the University of California at Los Angeles, who helped develop an award-winning $10 microscope for cellphones, said the simplicity of the new prototypes is a big advantage.

"They're further miniaturizing this stuff. But we also need to focus on getting these innovative designs out in the field, tested, improved and saving the lives of people," said Ozcan, who wasn't involved in the new study. "In that sense, all of us working on this technology are in the same boat."

Two existing cellphone-microscope designs inspired the new iteration, including Ozcan's and another called CellScope, designed by bioengineer Daniel Fletcher at the University of California at Berkeley. Because both models protrude from the cellphone's camera and have several delicate parts, Wachsmann-Hogiu set out to create a simpler and more compact design.

The team tucked a 1-mm-wide glass ball into a ring of rubber and slipped it over iPhone and iPhone 4 cameras. The images are magnified 350 times, but have a very thin plane of focus. To combat the resulting blur, the team created software able to stitch the sharp parts together into one crisp photo. They also made a prototype cellphone spectrometer (based on a patent they found) using narrow PVC tubing, electrical tape and a special grating able to split light into its component colors.

It costs about $20 to create the microscope and a few dollars to make the spectrometer, but Wachsmann-Hogiu said costs could easily drop below $10 for both. The tiny lenses could be made out of plastic instead of glass, and economies of scale could eventually kick in.

The team is working on improving the imagery of their microscope prototype and giving it the capability to detect microbes by fluorescence. They're also building a phone-based app to stitch images together, count blood cells and determine blood oxygenation levels.

Ozcan said he looks forward to new consumer technology as an opportunity to make an even cheaper and more powerful laboratories-on-a-chip.

"There are dreamlike components in consumer electronics," Ozcan said. "It's orders of magnitude more amazing than the science community could have imagined just decades ago."

DIY instructions to turn your own cellphone into a microscope are below.

Image: Standard microscope images (top row) compared to a iPhone microscope images (bottom row). Sickle-cell anemia blood is at left, and crystals are at right. (PLoS ONE/Sebastian Wachsmann-Hogiu et al./Center for Biophotonics at the University of California at Davis)

Citation: "Cell-Phone-Based Platform for Biomedical Device Development and Education Applications." Zachary J. Smith, Kaiqin Chu, Alyssa R. Espenson, Mehdi Rahimzadeh, Amy Gryshuk, Marco Molinaro, Denis M. Dwyre, Stephen Lane, Dennis Matthews and Sebastian Wachsmann-Hogiu. PLoS ONE, Vol. 6, Issue 3. March 2, 2011. DOI: 10.1371/journal.pone.0017150

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Cellphone Microscope - Step 1

Grab any cellphone with a camera, but note models that use touchscreen focusing and/or have manual focus options are best.

Find some thin, dark, rubbery material and poke a small hole in it (less than 1 millimeter in diameter). This can be done using a pin or needle.

Image: Zach Smith/Kaiqin Chu/Sebastian Wachsmann-Hogiu. Instructions adapted from text by Zach Smith and Sebastian Wachsmann-Hogiu.

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Posted: 11 Mar 2011 09:40 AM PST

The magnitude 8.9 quake that struck off Japan's coast on March 11 will go down as one of the country's largest earthquakes.

Even if its magnitude is downgraded in the coming days, as sometimes happens as more data are analyzed, the quake will remain a benchmark in a country that has seen many major quakes. It ranks fifth on the list of biggest quakes this past century. The Indonesian earthquake that spawned 2004's devastating Indian Ocean tsunami was a magnitude 9.1.

Japan's monster earthquake struck at 2:46 p.m. local time, about 150 km off the coast of the island of Honshu. Japan is one of the world's most prepared societies when it comes to earthquakes, and a recently established early warning system broadcast alerts in many areas, including Tokyo, before the shaking began.

Seismic activity in the region began with a magnitude 7.2 quake on March 3. Major aftershocks continue to rattle the area. The death toll is unknown.

Japan owes its lively seismic existence to its precarious geologic setting. The islands of Japan formed where one great plate of Earth's crust, the Pacific plate, dived beneath the Eurasian and Philippine plates. The collision is part of the "Ring of Fire" of earthquake and volcanic activity around the Pacific Ocean.

Chikyu, a deep-sea drilling vessel operated by the Japan Agency for Marine-Earth Science and Technology, is in the midst of a many-years study drilling into the seafloor off Japan's coast to study the genesis of big quakes there.

The deadliest quake in Japan's history came in 1923, when more than 140,000 people perished in the magnitude 7.9 Great Kanto Earthquake. That tremor was centered southwest of Tokyo Bay. The March 11 quake struck more to the north, offshore from the city of Sendai.

"Fortunately for Tokyo it's a bit further north than the great Kanto earthquake was, which means the damage in Tokyo is likely to be much less," Kevin McCue, a Canberra-based seismologist at CQUniversity in Australia, said in a statement.

Tsunami warnings spread across the Pacific in the hours after the earthquake; earthquakes generate tsunamis when the ground rupture displaces massive amounts of water. The size of the Japanese quake, plus its relatively shallow depth of 24 km, meant that it was primed to trigger tsunamis.

Honshu's east coast had essentially no time to prepare for the waves, but other locations around the Pacific set into gear preparation and evacuation plans polished after the 2004 Indian Ocean tsunami. Hawaii was reporting waves of 1 meter or less.

Japan Earthquakes Tsunami A computer model for the tsunami created by an 8.9-magnitude earthquake that struck 80 miles east of Honshu, Japan on March 11, 2011. Credit: NOAA/PMEL/Center for Tsunami Research

Image: A forecast for the tsunami caused by a magnitude-8.9 earthquake that struck off the coast of Japan on March 11, 2011. Heat-map colors show maximum tsunami height within the first 24 hours. (NOAA/PMEL/Center for Tsunami Research) [high-resolution version available]

Video: A computer model of tsunami propagation for the magnitude-8.9 earthquake that struck off the coast of Japan on March 11, 2011. (NOAA/PMEL/Center for Tsunami Research)

Posted: 10 Mar 2011 03:43 PM PST

Another piece of Star Trek technology has become a reality. Captain Kirk would instantly recognize new blueprints developed by a team of Chinese scientists as plans for a tractor beam.

The proposed device hasn't yet been built. But a similar one conceived by an American physicist was tested last year. Each device would fulfill the science fiction dream of reeling in objects using light — though neither could move anything bigger than a bacterium, much less a starship.

The Chinese plan, reported online Feb. 24 at arXiv.org, would use a laser to produce what is called a Bessel beam. This beam, unusual because it remains focused over large distances, could induce electric and magnetic fields in an object in its path. The spray of light scattered forward by these fields could push the object backward, against the movement of the beam itself. "This analysis established that light can indeed pull a particle…. Under appropriate conditions a [Bessel beam] can act as an 'optical tractor beam,'" write physicist Jun Chen of Fudan University in Shanghai and colleagues.

Physicist David Grier of New York University believes that the Chinese plan would work. And Grier should know: he designed his own tractor beam and built it, demonstrating for the first time that a beam of light can tug objects over long distances. His paper was published in the March 29, 2010, Optics Express.

"Both of these papers give us new tools," says Phil Jones, a physicist at University College London. "Something like this would have useful applications for moving particles. The effects are also quite size-dependent, so they might also be useful for sorting particles of different sizes."

A beam of light that can pull is counterintuitive to physicists, who have spent centuries studying light's ability to push.

"You normally think of light as being like a fire hose that just blows you downstream," says Grier. That's because when particles of light strike an object, they rebound like Ping-Pong balls and give a weak nudge. This radiation pressure is thought to shape the tails of comets and is useful for pushing solar sails in space.

The invention of the laser provided scientists with a stronger source of light and a push that could do useful work on Earth. Researchers now routinely use optical tweezers based on this push to pin down and manipulate atoms and small objects. But turning this push into a pull required more sophisticated optics — in Grier's case, a solenoid beam. Unlike traditional lasers, which are bright in the middle and dimmer at the edges, a solenoid beam contains a bright spiral of intense energy.

This corkscrew of energy tends to attract small spheres made of silica. The light in the corkscrew can then be tilted at an angle that kicks the spheres backward even as the beam itself moves forward. Like a tennis player sprinting away from the net while deftly lobbing the ball back at an opponent, this tilt can potentially push an object all the way back to the beam's source. Or it can be rotated to push forward. Switching between these states allows Grier to move objects back and forth.

The force of this push and pull, limited by the laser's strength and the speed of light, is small. But it's enough to tug 1.5-micrometer-wide spheres a distance of about eight micrometers — with much larger distances theoretically possible.

"You'd need a terawatt [or trillion-watt] laser to pull a person," says Grier. Being struck by that much energy, though, would likely incinerate the person being pulled. "It would be a short trip."

In a new paper to appear in an upcoming issue of Optics Express, Grier describes new schemes for his tractor beam that even Mr. Scott couldn't imagine. Instead of pulling objects along a simple straight line, Grier has begun to explore curves, loops and even knotted paths that cross themselves.

As a first demonstration, he guided spheres around ring-shaped tracks tilted in different three-dimensional orientations. This particle puppeteering, he says, could be useful in generating plasma currents to stabilize fusion power-generation technologies.

Video: Unlike traditional laser beams, solenoid beams in proposed tractor-beam devices contain a bright spiral of energy woven into their light. (David Grier/New York University/Science News/Vimeo)

Image: A new tractor-beam design tilts the angle of light within a laser beam to switch from pushing (left) to pulling (right) an object. Gray arrows show the angle of this tilt. Sang-Hyuk Lee, Yohai Roichman, and David G. Grier, "Optical solenoid beams," Opt. Express 18, 6988-6993 (2010)

Posted: 10 Mar 2011 12:50 PM PST

No limits on neurotoxic pollution by cement plants. No protecting endangered fish in San Francisco Bay. And no regulation of greenhouse gases.

Those are just some of the "riders" tacked onto HR1, the GOP spending bill defeated Wednesday in the Senate — but sure to return as Congress negotiates how the U.S. government will be supported.

The bill would have funded the government for the remainder of Fiscal Year 2011, which began last October and has been defined by the failure of Congress to agree on a budget.

As would be expected in any legislation this massive and urgent, HR1 contained hundreds of fine-print amendments that had little or nothing to do with federal spending, but reflected ideological wishes or political favors.

'This week's debate is just a dress rehearsal for the big stuff.'

David Goldston, the House Committee on Science chief of staff under President George W. Bush who now directs government affairs at the Natural Resources Defense Council, broke down how riders work after HR1 passed the House in February.

Many of the anti-environmental riders that passed after what Goldston called a "weeklong carnival of destruction on the House floor" were dropped from the original House plan. But more than a dozen remained.

Several would have ordered the Environmental Protection Agency not to fulfill its duty, legally mandated by Congress and the Supreme Court, to regulate greenhouse gas emissions. Other bills currently under consideration by Congress would do the same thing.

But the assault didn't stop there. HR1 would have cut the EPA's budget by nearly one-third. The agency would have been prevented from limiting pollution from a laundry list of neurotoxins and carcinogens — mercury, arsenic, PCBs, dioxins, heavy metals — at cement plants.

As Goldston recounts on an NRDC blog rundown of HR1's anti-environmental riders, the EPA estimates that cement plant restrictions would cost industry several hundred million dollars. In exchange, it would annually prevent 2,500 premature deaths, 1,500 heart attacks and 17,000 cases of asthma. Those public health benefits, or the cost of their absence, are worth between $6.5 billion and $17 billion.

The EPA would also have been blocked from updating its standards on soot pollution, which is responsible for up to half of current global-temperature increases. Neither would the agency be permitted to apply Clean Air Act standards to oil drilling in Alaska.

In California's San Francisco Bay and delta ecosystem, endangered fish would no longer be protected by the Endangered Species Act. (Ditto wolves in parts of the Rocky Mountains.) The proposed restoration of the San Joaquin River would be halted, as would cleanup efforts in Chesapeake Bay.

Under HR1, the Clean Water Act could no longer be used to restrict water pollution that killed wildlife. The EPA would have been prevented from developing handling procedures for coal ash, a carcinogen, and prevented from enforcing restrictions on mountaintop removal mining.

Even Rep. Joe Barton (R-Texas), best known for apologizing to BP during the Deepwater Horizon disaster, said the EPA-gutting was going too far. Scott Slesinger, the NRDC's legislative director, called HR1 "the most anti-environmental bill in 40 years."

The bill was defeated, 44-56, but its provisions are likely to return in other spending bills. As Mitch McConnell (R-Kentucky) said after HR1's Senate defeat, "This week's debate is just a dress rehearsal for the big stuff."

Images: 1) The former Holmes Road Incinerator in Houston. (Marc St. Gil/Documerica — a photography project commissioned by President Richard Nixon after the Environmental Protection Agency was established in 1970.) 2) Contaminated water in a ditch behind the Pittsburgh Glass Company. (Marc St. Gil)

Posted: 10 Mar 2011 12:49 PM PST

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NASA's prolific Mars Reconnaissance Orbiter turns five Earth years old Thursday.

Since settling into orbit around the Red Planet on March 10, 2006, MRO has transmitted more data to Earth -- 131 trillion bits and more than 70,000 images so far -- than all other interplanetary missions combined.

After the orbiter finished all its initial science objectives in the first two years, NASA extended its lifetime twice. The extra time let MRO watch Mars change over two-and-a-half Martian years, giving a new picture of a shifting, dynamic planet.

"Each Mars year is unique, and additional coverage gives us a better chance to understand the nature of changes in the atmosphere and on the surface," said Rich Zurek of NASA's Jet Propulsion Lab in a press release. "We have already learned that Mars is a more dynamic and diverse planet than what we knew five years ago. We continue to see new things."

MRO carries six science instruments, including radar that peels back the layers of the Martian surface, a spectrometer that has mapped the mineral content of three-quarters of the planet, and a weather camera that monitors clouds and dust storms.

But the show stopper is the HiRise camera (High Resolution Imaging Science Experiment), which can resolve features the size of a beach ball from 180 miles away.

To date, HiRise has snapped more than 18,500 close ups of Mars' canyons, craters and dunes. In honor of MRO's fifth birthday, here are some of our favorites.

Above:

Dust-Devil Tattoo

These twisty trails were traced by dust devils, spinning columns of rising air that pick up loose red dust grains and reveal darker, heavier sand beneath. Dust devils have been blamed for unexpectedly cleaning off the Mars rovers' solar panels. This image was taken Aug. 24, 2009.

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Images: NASA/JPL/University of Arizona

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Johnald's Fantastical Daily Link Splurge

2011-03-10T13:45:00.001-08:00

Johnald's Fantastical Daily Link Splurge

Farewell Discovery: Longest-Lived Shuttle’s Greatest Hits
Genetic Errors Nixed Penis Spines, Enlarged Our Brains
Tiny Fibers Put the Head on Stout Beer

Farewell Discovery: Longest-Lived Shuttle’s Greatest Hits

Posted: 09 Mar 2011 01:27 PM PST

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The space shuttle Discovery returned to Earth for the last time this morning, ending its reign as the world's longest running and most-traveled spaceship.

"It just played out the way we wanted it to," said Kennedy Space Center Director Bob Cabana in a press conference after the landing. "We wanted to go out on a high note, and Discovery has done that. We couldn't ask for more."

When it touched down at Kennedy Space Center in Florida at 11:57 EST on March 9, 2011, Discovery had flown 39 missions, spent a full 365 days in space, orbited the Earth 5,830 times and traveled more than of 148 million miles. It has carried 246 people into space, more than any other vehicle, including the first woman to ever pilot a spacecraft, the oldest person to fly in space, the first African-American to perform a spacewalk and the first sitting member of Congress to fly in space.

The shuttle's 27-year career hit several of the highlights of the space program, including delivering the Hubble Space Telescope to orbit in 1990 (and fixing it twice), carrying a 77-year-old John Glenn back into space in 1998, and leading NASA's return to space after the loss of Challenger in 1986 and Columbia in 2003.

On its final flight, the shuttle linked up with the International Space Station to deliver a new spare room full of supplies and science experiments, plus bring the first human-like robot into space.

"We're going to miss Discovery," International Space Station commander Scott Kelly told shuttle commander Steve Lindsey on Sunday, before Discovery's crew left the space station. "Discovery has been a great ship, and has really supported the International Space Station, more so than, I think, any other space shuttle. And we wish her fair winds and following seas."

Now that it's back on the ground, Discovery will retire as a museum piece at the Smithsonian. Here we look back at the veteran spacecraft's high points as the shuttle era draws to a close.

Image: NASA

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Posted: 09 Mar 2011 11:44 AM PST

Geneticists have linked the physical appearance of humans to patches of DNA lost in the 5 million years since we shared a common ancestor with chimpanzees. One loss prevented men from growing penile barbs, which chimps possess. Another enlarged some regions of our brain.

"We can know what makes us human, what makes us physically different from other animals and why," said developmental geneticist Gill Bejerano of Stanford University, an author of the March 10 study in Nature.

Only 2 percent of the DNA in our genome forms protein-coding genes. The rest, once called "junk DNA," helps control and coordinate gene activity. Out of this regulatory coordination, physiological complexity emerges.

Bejerano's team started by comparing the genomes of chimpanzees and macaque monkeys, which last shared a common ancestor 20 million years ago. They identified regions that hadn't changed in chimps, then compared these to corresponding stretches of the human genome. They found more than 500 mutations known as deletions, or stretches of DNA present in chimps but lost in humans.

Two deletions, one near a male hormone-signaling gene and another near a neural development gene, were especially intriguing. Tweaking those genes in mice suggested possible roles for the loss: eliminating penile spines and boosting cerebral cortex growth.

Bigger brains are an obvious advantage ("It probably helped us become the thinkers we are today," Bejerano said), but it's unclear why evolution weeded out the spines. These tiny, hair-like projections, found in male chimps and cats, can trigger female ovulation. They also increase sensitivity and remove existing sperm, ostensibly giving males a reproductive advantage. Bejerano suspects the spines are conducive to monogamy.

Could restoring the relevant regulatory DNA in humans resurrect penile spines? "I'm going to leave it to others to paint that picture and its consequences," said evolutionary biologist Sean B. Carroll of the University of Wisconsin, who wasn't involved in the study. "But my guess is that something would probably happen."

More practically, the findings underscore the importance of regulatory changes to human evolution. "Regulation is a choreograph critical to shaping how organisms appear. This research is going to be a hot trail to follow," said Carroll. "It's not just about what genes you have, but how they're used."

Image: Picture Taker 2/Flickr

Citation: "Human-specific loss of regulatory DNA and the evolution of human-specific traits."
Cory Y. McLean, Philip L. Reno, Alex A. Pollen, Abraham I. Bassan, Terence D. Capellini, Catherine Guenther, Vahan B. Indjeian, Xinhong Lim, Douglas B. Menke, Bruce T. Schaar, Aaron M. Wenger, Gill Bejerano and David M. Kingsley. Nature, Vol. 471, No. 7337, pp 216-219. March 10, 2011. DOI: 10.1038/nature09774

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Tiny Fibers Put the Head on Stout Beer

Posted: 09 Mar 2011 11:19 AM PST

Irish mathematicians have discovered tiny plant fibers can make nitrogen bubbles out of stout beer and form a creamy head of foam. The find could mean an end to more expensive and less-eco-friendly technology currently used to create fizz.

Nitrogen-infused stouts are known for their long-lasting and creamy heads, a feature that carbonated beers can't emulate. But nitrogen doesn't froth up on its own, so to get foam on a canned stout, brewers insert a widget — a small plastic ball with a hole in it. When a can is opened, the widget releases pressurized nitrogen into the beer, which then triggers more dissolved nitrogen in the beer to bubble out.

But a graduate student supervised by applied mathematician William Lee at the University of Limerick in Ireland discovered that microscopic plant fibers made of cellulose, such as cotton, can also froth up a stout.

"What happens around these fibers is really complex, so it's a ripe area for research," said Lee, who posted his team's research March 2 on arXiv.org. "This is also a matter of national pride. Stout beers are as culturally important to Ireland as champagne is to France."

Carbon dioxide dissolves into beer during the brewing process, and the gas quickly nucleates to form bubbles in the liquid with the help of special surfaces. Microscopic plant fibers that hide in drinking glasses are especially good at bubbling up carbon dioxide because they trap small air bubbles that make for excellent nucleation sites. But carbonated brews form large, fragile bubbles and heads that quickly fizzle out.

To create longer-lasting and creamier heads in stouts, brewers pump the beer full of nitrogen because the gas forms smaller, more stable bubbles without affecting taste. A tiny opening in the nitro bartaps forces nitrogen into stouts as the beer is poured, but canned stouts are trickier because plant fibers don't help nitrogen bubble out. Or, so beer experts thought.

Lee and his team recorded stouts under a microscope (video above) to watch bubbles form inside cellulose fibers. They discovered the bubbling rate was up to 20 times slower than in carbonated brews, which is probably why no one had noticed it before.

"If you line a can with enough of them, you can get a creamy head in less than 30 seconds," Lee said, roughly the time it takes to open and pour a stout.

It takes roughly 4.3 million microscopic fibers to accomplish the feat, which translates to a postage-stamp-sized pad of fibers. Food-safe cellulose should be cheaper than widgets to put into cans, Lee said, especially since the latter require a de-oxygenation process to prevent spoiling the beer.

Lee and his team hopes their discovery will make stouts slightly cheaper (on the order of a few cents per can), in addition to creating new research leads in fluid mechanics.

Video: Pockets of air trapped in tiny cellulose fibers, each between 10 and 50 microns wide, help nitrogen and carbon dioxide bubble out. Courtesy of Michael Devereux/Mathematics Applications Consortium for Science and Industry

Image: A plastic widget found in a can of Guinness stout beer. slworking2/Flickr

Via Technology Review

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Johnald's Fantastical Daily Link Splurge

2011-03-09T13:03:00.001-08:00

Johnald's Fantastical Daily Link Splurge

Physics of Pruney Fingers Revealed
Photo: Mad Dash to Catch Space Shuttle Crossing the Sun
Experts Push NASA to Focus on Search for Life
Data as Art: 10 Striking Science Maps

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.

Citation:
"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

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 Wired.com. "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

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

<< Previous | Next >>

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.

Above:

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]

<< Previous | Next >>

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Johnald's Fantastical Daily Link Splurge

2011-03-08T13:36:00.001-08:00

Johnald's Fantastical Daily Link Splurge

Video: Elephants Lend a Helping Trunk, Pass Cooperation Test
Alien Microbe Claim Starts Fight Over Meteorite
Sleep Quality May Be Tied to Covert Brain Wave

Video: Elephants Lend a Helping Trunk, Pass Cooperation Test

Posted: 07 Mar 2011 02:10 PM PST

Asian elephants have passed a test of cooperation with flying colors, one that cognitive psychologists say demonstrates an ape-level awareness and sense of teamwork. Their collaboration isn't just the product of rote learning, but the result of careful thought.

In the wild, of course, elephants routinely work together. But that doesn't pass laboratory muster, said University of Cambridge psychologist Joshua Plotkin.

"It's anecdotal evidence. These animals are empathetic, they're cooperative. But how empathetic? How cooperative?" he said. "The best we can do is institute controls, do experiments like this, and figure out how what they do is unique from learning."

Plotnik's experiment, published March 8 in the Proceedings of the National Academy of Sciences, was conducted when he was a student of famed Emory University ethologist Frans de Waal. In 2006, they showed that elephants could recognize themselves in a mirror, a benchmark feat believed to indicate an especially sophisticated level of self-awareness, on par with that of young humans.

Though important, mirror self-recognition is just one test, and doesn't address the sort of cooperative behavior for which elephants are famed in the wild. They're known to help individuals in distress, cooperate in rearing children, and may even mourn their dead. From a behavioral perspective, they clearly demonstrate empathy.

But behavioral records from the wild are not the currency of cognitive psychology. After all, bees display incredible coordination, but few people would compare an individual bee's consciousness to that of a person. According to Plotnik, it could be argued that elephants and other cooperative animals are acting reflexively rather than thoughtfully. So he and de Waal turned to a test originally developed to measure cooperation in chimpanzees.

In the original test, two chimps pulled on ropes attached to an otherwise inaccessible, food-containing box too heavy for one alone to move. In the version updated for elephantine strength — a too-heavy box would have been "as big as a 747," said Plotnik — the rope was arranged so that if one elephant pulled alone, its partner couldn't reach the rope. To get a banana treat, both had to pull simultaneously.

Plotniks' elephants pick the trick up quickly. Then, in the study's key step, they demonstrated patience. If only one elephant was present, it would wait for a partner to arrive. Until then, it wouldn't try to pull the rope, and often wouldn't pick it up.

If the elephants pulled automatically, it would be evidence of reflexive behavior, said Plotnik. Waiting indicated something more. They understood that their own effort wasn't enough. They understood their partner's role. (One elephant, seen in the video below, even figured out how to cheat. By standing on her end of the rope rather than pulling, her partner had to do all the work — not very nice, perhaps, but smart.)

Plotnik's now working on other, more sophisticated tests of elephant cooperation. He hopes to measure how they see other species, process information in the wild, find food and water, and care for one another. But he acknowledges that Asian elephants are unique among social, cooperative animals in their amenability to study. Other animals — say, lions — may be just as smart, but not so easy to test.

"Just because something hasn't been tested doesn't mean you reject it as not being possible," he said.

Video: 1) Two Asian elephants help each other pull closer a table bearing banana treats./Joshua Plotnik, University of Cambridge. 2) An especially clever Asian elephant named Neua Un figures out how to make her partner do all the work./Joshua Plotnik, University of Cambridge.

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Citation: "Elephants know when they need a helping trunk in a cooperative task." By Joshua M. Plotnik, Richard Lair, Wirot Suphachoksahakun, and Frans B. M. de Waal. Proceedings of the National Academy of Sciences, Vol. 108 No. 10, March 8, 2011.

Alien Microbe Claim Starts Fight Over Meteorite

Posted: 07 Mar 2011 01:53 PM PST

NASA astrobiologist Richard Hoover thinks he's found fossilized alien bacteria inside a meteorite. If he's right, it's world-shaking news. But that's a very, very big if.

"There are legitimate reasons to initially be skeptical of these findings," wrote University of Oklahoma geophysicist Michael Engel in a commentary published March 7 by the Journal of Cosmology, where Hoover's claims were announced on March 4. Nevertheless, "I encourage people to keep an open mind when forming an opinion as to the significance of this work."

Hoover's claims involves carbonaceous chondrites, a class of rare meteorite that formed early in the solar system's history and contain organic chemicals, ostensibly picked up on their passage through space.

When those chemicals are found on Earth, they're considered signs of life. When found in a meteorite, their origin is intriguing but undetermined — a likely sign of contamination by Earthly chemicals or microbes, but hypothetically evidence of extraterrestrial life.

According to Hoover, he hasn't just found suggestive chemical traces, but complex filament-like structures that could only come from bacteria. Because there's no nitrogen in the meteorites, and Earthly microbes always contain nitrogen, he concludes that these fossils must come from life that evolved elsewhere.

"This finding has direct implications to the distribution of life in the Cosmos," wrote Hoover, with great understatement.

The claims have already set off an internet tempest of commentary, some of it noting Hoover's fringe announcement venue. The Journal of Cosmology is non-peer reviewed. It's also produced by a community of astrobiologists who are zealously evangelical about galactic panspermia, or the notion that Earth was seeded by life arriving from space.

Fifty years ago, that notion was crackpot. Nowadays, it's rather more plausible, if not so certain as some proponents insist. Life's building blocks have been found in comets, which could serve as spacefaring petri dishes. There are likely billions of Earth-like planets just in the fraction of space visible to the Hubble telescope. Given trillions of years and billions of opportunities, other examples of self-replicating chemicals don't seem improbable.

"I see no convincing evidence that these particles are of biological origin."

Beyond the venue, however, critiques of Hoover's claims become more substantive. "As a microbiologist who has looked at thousands of microbes through a microscope, and done some of my own electron microscopy, I see no convincing evidence that these particles are of biological origin," wrote SETI Institute astrobiologist Rocco Mancinelli in an email to Wired.com.

"The main claim of similarity with modern earthly analogues is totally inadequate," said University of Croatia microbiologist Stjepko Golubic, who specializes in the sort of bacteria to which Hoover compared the alleged fossil remains. "It is important to note that the SEM" — scanning electron microscope, used in this study — "is an inadequate tool for identifying cyanobacteria and this includes those images offered in this paper for comparison."

Mancinelli also criticized Hoover's sterilization techniques, which were not fully described in the paper. "It is unclear to me if the techniques used for the analyses were adequate. For example, the paper states that the implements used were flame sterilized. Does that mean they were placed in a Bunsen burner where soot" — which could confound the results — "could get on them?" Mancinelli wrote.

NASA astrobiologist Chris McKay defended Hoover's practices, saying he is "a careful and accomplished microscopist so there is every reason to believe that the structures he sees are present and are not due to contamination."

"If these structures had been reported from sediments from a lake bottom there would be no question that they were classified correctly as biological remains."

"If these structures had been reported from sediments from a lake bottom there would be no question that they were classified correctly as biological remains," wrote McKay. (Note: Though they share a surname, it was NASA astrobiologist David McKay who lead a team that in 1996 reported evidence of Martian microbes in a meteorite. That claim remains inconclusive.)

Nevertheless, the structures could conceivably be random. They could also just be fossilized bugs from Earth, said Allan Treiman, planetary petrologist at the Lunar and Planetary Institute in Houston.

"The meteorites Dr. Hoover studied are rich in carbon compounds that formed off of the Earth. However, Earth microbes do not know the difference, will eat alien carbon with gusto," he said. "Because all of these meteorites have been on the Earth for many years, and have not been kept isolated from Earth microbes, it's certain that they have been exposed to Earth microbes."

Yet Engel is less willing to draw conclusions. Independent experts need to analyze Hoover's images, and it would be useful if there were better grounds for comparison than visual similarity with known bacteria, he wrote.

According to Engel, his own analyses of a meteorite analyzed by Hoover found no evidence of common amino acids, suggesting that Earthly microbes had not invaded them.

"Faced with the actual possibility of evidence for extraterrestrial life, we quite often feel more compelled to ignore it or refute it rather than embrace it," wrote Engel. "Perhaps this has something to do with our inherent fear of the unknown."

SETI research director Jill Tarter compared Hoover's findings to the controversial recent discovery of extremophile bacteria that may metabolize arsenic, something never before seen on Earth and suggestive of how extraterrestrial bugs could survive in supposedly inhospitable environments.

Like that claim, Hoover's "may turn out to be correct, but it has not yet been proven," said Tarter. "Incredible claim; incredible evidence, not so much."

Dave Mosher contributed to this report.

Image: Journal of Cosmology

See Also:

Citation: "Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites." By Richard B. Hoover. Journal of Cosmology, March 2011.

Sleep Quality May Be Tied to Covert Brain Wave

Posted: 07 Mar 2011 06:57 AM PST

Making waves isn't conducive to staying asleep, at least when the waves are a type of brain signal associated with being awake.

A type of brain activity known as an alpha wave emanates from the back of the head when a person is awake but relaxing with eyes closed. Scientists used to think that the wave was subdued and disappeared as a person fell deeper and deeper into sleep.

But the alpha wave doesn't disappear; it just goes undercover during sleep, researchers report online March 3 in PLoS One. The covert alpha wave may help determine how deeply people sleep and how much noise is needed to rouse a sleeper.

The finding "stresses that sleep is really a dynamic process," says Mathias Basner, a sleep researcher at the University of Pennsylvania in Philadelphia who was not involved in the study. The study shows that sleep doesn't happen just in discrete blocks, as most charts of sleep stages would indicate. Instead, brain activity changes from moment to moment during sleep.

"It may suggest that something is going on in the central nervous system that we don't know about and should maybe pay more attention to," Basner says.

Scientists hadn't ignored alpha waves on purpose, says study coauthor Scott McKinney, a sleep scientist at Massachusetts General Hospital and Harvard University. Researchers typically measure brain activity during sleep with electroencephalographs, or EEGs, devices that use electrodes on the scalp to detect electrical activity in the brain. The squiggly lines recorded by the EEG can be hard to interpret with the naked eye, so McKinney and his colleagues used computer programs to break the EEG signals from 13 volunteers down into discrete waves. The analysis revealed that alpha waves never truly go away; they just get drowned out by more vigorous signals the way spreading ripples from a small rock dropped in a pond are swamped by waves from a passing speedboat.

Alpha wave activity decreases as people enter ever-deeper levels of sleep and increases as people cycle back into more shallow sleep stages. In study participants, the ups and downs of alpha wave activity were closely associated with how easily a person could be awoken by traffic noises, loud talking or other sounds that might be encountered in hospital or at home in a city. When alpha wave activity spiked just before a noise was played, volunteers woke up more easily than when alpha wave activity was low, the researchers found.

Alpha wave activity may be the brain's way of keeping people aware of their surroundings during sleep, speculates Phyllis Zee, director of the Sleep Disorders Program at Northwestern University in Chicago. Such awareness enables people to wake quickly in case of danger, but too much alpha activity might also have a downside if it prevents a good night of sleep.

People with insomnia commonly complain that they are very light sleepers and are always aware of their surroundings, Zee says. Although many insomniacs get a full night of sleep, they report that their sleep is not restful. But laboratory tests often don't show any abnormalities.

"The classical way we're scoring sleep may not give a good handle on what a patient really experiences," she says. "This new way of analyzing depth of sleep may be used to get a better understanding of a patient's complaint."

Image: cobalt123/Flickr

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Johnald's Fantastical Daily Link Splurge

2011-03-05T13:24:00.001-08:00

Johnald's Fantastical Daily Link Splurge

Satellites See Evidence of One-Two Asteroid Punches on Mars
NASA Climate Satellite Crashes After Launch
Cosmic Rays May Not Come From Supernovas

Satellites See Evidence of One-Two Asteroid Punches on Mars

Posted: 04 Mar 2011 11:46 AM PST

New images from two Mars-orbiting satellites capture times when the planet was pummeled by at least two meteorites at once.

The slug-shaped crater above, photographed on Aug. 4, 2010 by ESA's Mars Express spacecraft, was probably carved by a chain of projectiles coming in at a shallow angle. The 48-mile-long crater has no name, but it lies in Mars' heavily cratered southern highlands, just south of a large crater called the Huygens basin.

Astronomers have speculated that similarly oblong basins were formed by one oblique impact or by volcanic flows. But the shape of the material tossed out of this crater in the initial impact, called the ejecta blanket, suggests the unnamed scar came from a double punch. The blanket shows two distinct lobes like butterfly wings, hinting that each blob was excavated by a different incoming rock.

Three deeper areas inside the crater itself suggest that there could have been more than two impactors. Smaller craters that lie to the gouge's right probably formed later.

A photo taken Jan. 10 with NASA's HiRISE camera is even more striking. The image below shows two symmetrical, neatly overlapping craters that must have formed at the same time.

The assailing rocks could have been parts of a once-intact body that broke up on its way through Mars' thin atmosphere before slamming into the surface. Several known celestial bodies, including the rubbly asteroid Itokawa and the chicken-leg-shaped comet Hartley 2, would likely break in two and form simultaneous impact craters if they smacked into a planet.

Although planets suffer fewer slings and arrows now than they did in the solar system's youth, Mars is headed for another rough time. One of its moons, Phobos, will collide with the planet in a few tens of millions of years, breaking up in the process to form more wonky-shaped impact craters.

Images: 1) ESA/DLR/FU Berlin (G. Neukum). 2) NASA/JPL/University of Arizona

Posted: 04 Mar 2011 09:32 AM PST

By Mark Brown, Wired UK

The rocket carrying NASA's Glory satellite, an observation spacecraft designed to study the effect atmospheric particles have on the planet's climate, has failed to reach orbit due to an engineering glitch with its nose cap.

The Taurus XL rocket blasted off from the Vandenberg Air Force Base in California earlier this week, but just minutes after liftoff it suffered from a technical failure. The rocket's "fairing" — an aerodynamic cone designed to separate during the trip into space — didn't come off as planned.

"Telemetry indicated the fairing did not separate as expected about three minutes after launch," a NASA statement read. Without that crucial separation, the 1,160-pound rocket and satellite combo was too just heavy to reach its intended orbit 438 miles above Earth.

The $424 million satellite would have gone on a three-year mission to improve our understanding of how the sun and atmospheric particles called aerosols affect the planet's climate. It would have established the magnitude of aerosols in the atmosphere, and measured variations in the amount of radiation that enters Earth's atmosphere during the sun's decade-long solar cycle.

The mission was originally plagued by a computer glitch which caused a delay of more than a week. It also comes almost exactly two years after NASA's Orbiting Carbon Observatory (OCO) — another climate-tracking satellite that would have measured carbon dioxide levels — crashed into the ocean with an almost identical technical failure.

On 24 February 2009, the Taurus XL also failed to shed its protective fairing, and couldn't reach orbit. It crashed down in the ocean near Antarctica, putting the $270m satellite out of commission. At the time, NASA launch director Chuck Dovale said, "Our goal will be to find a root cause for the problem. And we won't fly Glory until we have that data known to us."

A duplicate version of Glory is now scheduled to launch from Vandenberg in 2013.

Original story on Wired UK

Image: NASA

Posted: 04 Mar 2011 07:00 AM PST

The confirmed origin of ordinary cosmic rays may need to be unconfirmed.

New data gathered by an instrument onboard a Russian spacecraft challenge the theory that most cosmic rays are fueled by supernovas, the explosions created by dying stars.

"The mechanism for the acceleration of cosmic rays needs to be completely revised," says Piergiorgio Picozza, a physicist at the University of Rome Tor Vergata in Italy. Picozza is a co-author of a March 3 paper in Science detailing the new observations of the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics, or PAMELA, instrument.

Cosmic rays aren't actually rays. They're fast-moving particles that carry an extraordinary amount of energy and continuously bombard the Earth from every direction. The most popular explanation for the origin of these particles points to shock waves created by far-off supernovas, one of the few phenomena in the cosmos powerful enough to impart such energy.

According to that explanation, known as the diffusive shock acceleration mechanism, clouds of charged gas rush outward during a supernova and generate strong magnetic fields. These magnetic fields could accelerate charged particles to tremendous speeds and eject them into space.

Orbiting hundreds of kilometers above Earth, the PAMELA detector spent three years collecting cosmic ray particles; mostly nuclei of hydrogen and helium with energies ranging from a billion to a trillion electron volts, which is comparable to the energy of protons in the biggest particle accelerator in the United States.

Magnetic fields in a supernova should accelerate both hydrogen and helium particles in the same way: Graph the mathematical equations describing this push, and the curve for each particle should have the same slope. But in the PAMELA data, Picozza found a difference in these slopes that a single shock wave can't explain.

"The two particles seem to be accelerated by different mechanisms," he says.

Scientists should investigate other astronomical objects as possible sources of cosmic rays, Picozza says. One place to look proposed by Russian physicists is in the novas, or smaller explosions, produced when white dwarf stars belch out energy. Another option is giant superbubbles of gas blown around the universe by stellar winds, says Picozza.

But Mikhail Malkov, a plasma physicist at the University of California, San Diego, who studies supernova shock waves, isn't ready to toss out the existing cosmic ray theory. "The data look statistically significant, but it's too early to say that the supernova acceleration model is in trouble. This statement is too strong," says Malkov.

Space telescopes peering into the remnants of supernovas have found lots of evidence over the years to support the supernova shock wave theory — including gamma rays that reveal the structure of magnetic fields, and missing energy that could have been spent making cosmic rays.

Malkov says the difference between Picozza's hydrogen and helium curves is small, and it could be accounted for simply by tweaking the existing supernova model. Malkov hasn't worked out the details yet, but he suspects that PAMELA may be seeing cosmic rays created by a shock wave that wasn't completely uniform or a mishmash of particles released by two different supernovas.

Image: Illustration of a cosmic ray shower. (Cosmus/University of Chicago)

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Johnald's Fantastical Daily Link Splurge

2011-03-04T13:41:00.001-08:00

Johnald's Fantastical Daily Link Splurge

iPad Lets Scientists Drag, Pinch and Swipe Real Molecules
Deepwater Horizon’s Impacts Found in Bacteria
Engineered Viruses Boost Memory Recall in Mice
4 New Species of Zombifying Ant Fungus Found
An Unknown Ocean: The Other Rhythms of Life

iPad Lets Scientists Drag, Pinch and Swipe Real Molecules

Posted: 03 Mar 2011 04:03 PM PST

Using laser beams to control individual molecules is a precise, difficult operation rendered nearly impossible by the limitations of the computer mouse.

Unless you have the right iPad app.

New software called iTweezers lets scientists drag molecules around the screen as easily as shooting angry birds at pigs.

"It's cool because it takes something that normally lives on a lab bench, and makes it so simple," said physicist Richard Bowman of Scotland's University of Glasgow, lead author of a paper in the March 4 Journal of Optics describing the new software. "We have visitors who have never seen an optical tweezer before in their lives, and they happily move particles around."

'You can learn stuff by physically connecting in a different way.'

The new app is an interface for controlling optical tweezers, an instrument that uses laser light to trap and move microscopic objects. It works a little like a sci-fi tractor beam: The radiation from a tightly focused beam of light applies enough pressure to tiny objects like cells or proteins to pin them to the spot or push them around.

The invention of optical tweezers won Secretary of Energy Steven Chu a Nobel Prize in Physics, and they have proven their worth in biology labs, where they have been used to trap and manipulate everything from viruses to DNA. They have helped measure some of the smallest forces ever recorded, detected how DNA's double helix unzips, and watched molecular motors move matter around inside cells.

But most of the early experiments with optical tweezers could only focus on one spot at a time.

"Up till now, people typically controlled things using a mouse," said physicist Gordon Love of Durham University in England, who was not involved in the new work. "A mouse is great for moving around one thing like a cursor on a screen, but it's no good for moving around multiple things."

The multitouch interface was born when Bowman's colleagues at England's University of Bristol struggled to control a tiny rod about 300 nanometers wide. To keep the rod from flipping over, the physicists needed to pin the rod down in several places at once.

In 2009, the team built a custom table that let them drag and drop microscopic glass beads just by swiping their fingers along a layer of paper coated with silicon rubber. The device was clunky and complicated, but it mostly worked.

But soon the team found a more elegant setup: the iPad.

"When the iPad came out we thought, well hey, this is just like the big table, except it's small and works really well," Bowman said.

The physicists shine laser light through a high-powered microscope onto a slide holding whatever objects the scientists are interested in. Bowman's lab usually uses glass beads about two microns across, which are used in many experiments as a handle for harder-to-grasp molecules.

Before entering the microscope, the laser beam bounces off a tiny LCD screen that splits the beam and steers it around to focus on several beads at once.

A computer tells the LCD screen to display specific holograms designed to bend the laser light in specific ways. The app Bowman and colleagues use to write the holograms is available on iTunes as iHologram.

"It's fun to use and quite visually attractive," Love said. "My young daughters play with it. They have no idea about optical tweezers, but they think it's fantastic."

The iPad displays the view through the microscope, and wirelessly sends the computer the information on where the user's fingers are. A user can select up to 11 different objects by tapping them, move them around by dragging them, and use the pinch-zoom feature to move the objects up and down in space.

Theoretically, scientists could be sitting on the couch with an iPad at home moving beads or molecules in the lab. But so far, the method hasn't made it out of the University of Glasgow physics lab. The researchers hope to bring it into other labs to help biologists and chemists run complicated experiments without stressing about the technology.

"The interface makes it really easy," Bowman said. "If somebody comes along and sees my computer program with about a bajillion controls on it, it's a bit off-putting. Whereas the iPad lets you get stuck right in there and move stuff around, without having to worry about setting up all the physics behind it."

Feeling like you can directly touch cells and molecules can also help build an intuitive sense of the microscopic world, Bowman says. His lab has also developed a way to manipulate molecules with a joystick that transmits the forces the molecule feels to the user's hand, like a video game with tactile feedback. Bowman says you can even feel water molecules jiggling around your trapped molecule.

"The interface stuff is fun, but I think you can learn stuff by physically connecting in a different way," he said. "You get a feel for how things work."

Video and image: Richard Bowman/University of Glasgow

Citation: "iTweezers: Optical micromanipulation controlled by an Apple iPad" (.pdf). R.W. Bowman, G. Gibson, D. Carberry, L. Picco, M. Miles and M.J. Padgett. Journal of Optics, Vol. 13, March 4, 2011.

Posted: 03 Mar 2011 03:17 PM PST

Nobody's going to shed a tear for an oiled microbe, but the Deepwater Horizon's impacts include bacteria, underscoring just how subtle and fundamental the blowout's ecological consequences may be.

The findings, based on comparisons of microbial flux before and after oil washed ashore, are not a final analysis. It's too soon to say how long-lasting those fluctuations were, or what they meant to other creatures. Instead they're a starting point, an early observation in research that will continue for years, even decades.

"While visible damages are evident in the wildlife populations and marine estuaries, the most significant effect may be on the most basic level of the ecosystems: the bacterial and plankton populations," wrote researchers in a study Feb. 28 in Nature Precedings. "Abrupt and severe changes in the microbial metabolism can produce long-term effects on the entire ecosystem."

Led by biologist William Widger of the University of Houston, the researchers sequenced DNA from near-shore water and beach-soil samples gathered before and after oil arrived in Gulfport, Mississippi, and Grand Isle, Louisiana, following the blowout last spring.

By cross-referencing the DNA to microbe gene databases, they identified populations of bacteria and how they changed. Vibrio cholera, the bug that causes cholera, spiked upward after the spill. So did Rickettsiales, an order of bugs whose diseases include typhus and spotted fever.

Populations of Synechococcus, a typically ubiquitous photosynthesizing bug, collapsed. Communities of Archaea — the lesser-recognized microbial kingdom — also underwent radical makeovers.

The new analyses are not meant to be exhaustive. Most species of ocean-dwelling microbes have not yet been identified. Rather, they're a diagnostic snapshot that wouldn't have existed even a decade ago, before the advent of faster, cheaper gene sequencing and a rising appreciation of bacteria's ecological importance.

"Microbial communities are an essential but vulnerable part of any ecosystem. The basic metabolic activities of microbial communities represent the fundamental status of any environment," wrote Widger's team.

Andy Juhl, a Columbia University plankton ecologist who was not involved in the study, cautioned against drawing premature conclusions. "I would take the findings that oil resulted in these changes in microbial composition as a plausible hypothesis," he said. "Further work may support or refute that hypothesis."

Juhl's assessment is in keeping with scientific debate over a growing body of research into exactly what poured and bubbled from the Deepwater Horizon wellhead, and what it meant to the Gulf's already-troubled ecologies. The research is still in its early stages, painstakingly gathered and deliberated — as it will be for years to come — even as BP has reneged on restoration agreements, arguing that the damage wasn't so bad after all.

In mid-February, researchers led by University of Georgia biogeochemist Samantha Joye concluded that up to 40 percent of hydrocarbons released by the blowout came in the form of methane gas. Its fate remains unknown, and vast methane pockets could still be floating through the Gulf, they said.

Those findings were criticized as relying on outdated data by oceanographers John Kessler and David Valentine, who a month earlier said that the methane had been consumed by deep-sea bacteria.

The disagreement was a standard scientific back-and-forth, but much less debatable were seafloor movies subsequently shown by Joye at the American Association for the Advancement of Science meeting in Washington, D.C. Shot by a robotic submersible vehicle in December, the films showed a Gulf seafloor covered with oil and dead invertebrates.

What all this ultimately means for Gulf ecology is unknown. As for human impacts, the National Institutes of Health announced on March 1 that it's looking for 55,000 oil cleanup workers to participate in a long-term study of chemical impacts on health.

In the meantime, the oil industry and Gulf lawmakers continue to push for lifting restrictions on deepwater drilling. Kenneth Feinberg, administrator of the $20 billion claims fund established by BP, has said that Gulf ecosystems should be fully recovered by 2012.

"One viewpoint, which is what BP would want us to believe, is that this oil and gas had been naturally dispersed and had a relatively minor effect, and perhaps no long-term impact on the health of the Gulf of Mexico ecosystem. The other point of view is that it killed lots of animals, oiled wetlands and may have long-term ecological impacts, but it's too early to assess that," said Ian MacDonald, a Florida State University oceanographer and co-author with Joye of the methane estimates.

"We all hope the first one is correct, but we should try to be very objective about determining what really did happen," he said.

Widger's group concluded that "the long-term damage to the ecosystem including the basic food chain is uncertain and requires future research."

Images: 1) Geoff Livingston, Flickr. 2) Samantha Joye, University of Georgia.

See Also:

Citation: "Longitudinal Metagenomic Analysis of the Water and Soil from Gulf of Mexico Beaches Affected by the Deep Water Horizon Oil Spill." By William R. Widger, Georgiy Golovko, Antonio F. Martinez, Efren V. Ballesteros, Jesse J. Howard, Zhenkang Xu, Utpal Pandya, Viacheslav Y. Fofanov, Mark Rojas, Christopher Bradburne, Ted Hadfield, Nels A. Olson, Joshua L. Santarpia & Yuriy Fofanov. Nature Precedings, February 28, 2011.

Engineered Viruses Boost Memory Recall in Mice

Posted: 03 Mar 2011 12:19 PM PST

By John Timmer, Ars Technica

Memories fade with time, often to the annoyance of those who can't recall important details. But scientists have now found a way to boost the recall of memories even after they've started to fade. Unfortunately, the method involves injecting an engineered virus directly into the brain, so those of us who are bad with names may want to wait a bit for the technique to be refined.

The work was done in rats, and the memories in question are associations between a specific taste — saccharine, for example — and an unpleasant stimulus, caused by injection of a nausea-inducing drug (the approach is called "conditioned taste aversion"). Unless the unpleasant association is reinforced, the memories will slowly fade with time, although the aversion doesn't disappear entirely during the two-week period that the authors were looking at.

Two years ago, the same authors found that it was possible to radically accelerate this fading. By injecting a chemical that blocked a specific brain enzyme (protein kinase M ζ), the authors caused the rats to act as if they had never experienced the nausea, even if the memory manipulation took place 25 days after the conditioning. Most chemicals that interfere with memories tend to prevent them from being consolidated for long-term storage, but this chemical seemed to work even after the memory was firmly in place.

That's potentially helpful, since some people have formed negative associations with harmless or even helpful items. Still, for most of us, it would be nice to think that fading memories could be resuscitated. Apparently, they can. The researchers have now done what's effectively the converse experiment, and increased the activity of protein kinase M ζ. They did this by engineering a virus to express the gene for the kinase, and then infected specific areas of the brain involved in memory. All the infected cells had additional copies of the gene, and thus made more of its product.

The virus had exactly the effect that the authors would presumably have predicted. The virus was injected a week after the rats were given the aversion conditioning, when the memory would already be starting to fade, and the memory tests were done a week after that, yet rats showed a significantly improved retention of their memories. As the authors point out, the engineered virus boosted a memory that was formed before it was even present.

The memory molecule, PKMzeta, overexpressed in rat neurons. Red (left) shows PKMzeta while green (middle) is a fluorescent protein that shows nerve cells have been infected by viruses engineered to boost the memory molecule. Yellow (right) shows both the memory molecule and green fluorescent protein only overexpress at certain locations in the neuron. Weizmann Institute of Science/Science

Actually, you can make that memories, plural. The authors trained rats to avoid both saccharine and salty liquids over the course of three days, and then injected the virus a week after the last training. The memories of both of these trainings were enhanced by the presence of the viral protein kinase M ζ gene.

The authors can't tell exactly what protein kinase M ζ is doing to increase the recall of memories, and suggest it could be either enhancing the association between taste and the unpleasant experience, or simply enhancing recall in general. Although they don't mention it, their findings may also be limited to specific classes of memories, like the associations examined here.

That latter point makes the last sentence of the paper a bit over the top, as the authors suggest that a chemical that enhances protein kinase M ζ activity might make for a good treatment for memory disorders like amnesia and age-related decline. Until we have a clearer sense of how many types of memories it works for, that's a bit premature. Fortunately, there are lots of ways to test the recall abilities of animals, many of which don't involve negative associations. Hopefully, testing of the virus' more general impact on memory is already underway.

Image: HIV (green dots), a member of the lentivirus genus. (C. Goldsmith/P. Feorino/E. L. Palmer/W. R. McManus/CDC)

Citation: "Enhancement of Consolidated Long-Term Memory by Overexpression of Protein Kinase Mζ in the Neocortex." Reut Shema, Sharon Haramati, Shiri Ron, Shoshi Hazvi, Alon Chen,
Todd Charlton Sacktor and Yadin Dudai. Science, Vol. 331, March 3, 2011. DOI: 10.1126/science.1200215

Source: Ars Technica

Posted: 03 Mar 2011 09:50 AM PST

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Four new species of brain-manipulating fungi that turn ants into "zombies" have been discovered in the Brazilian rain forest.

These fungi control ant behavior with mind-altering chemicals, then kill them. They're part of a large family of fungi that create chemicals that mess with animal nervous systems.

Usually scientists study these fungi as specimens preserved in a lab, said entomologist David Hughes of Pennsylvania State University, co-author of a study March 3 PLoS ONE. "By going into the forest to watch them, we found new micro-structures and behaviors."

Once infected by spores, the worker ants, normally dedicated to serving the colony, leave the nest, find a small shrub and start climbing. The fungi directs all ants to the same kind of leaf: about 25 centimeters above the ground and at a precise angle to the sun (though the favored angle varies between fungi). How the fungi do this is a mystery.

"It's related to the fungus that LSD comes from," Hughes said. "Obviously they are producing lots of interesting chemicals."

Before dying, ants anchor themselves to the leaf, clamping their jaws on the edge or a vein on the underside. The fungi then takes over, turning the ant's body into a spore-producing factory. It lives off the ant carcass, using it as a platform to launch spores, for up to a year.

"This is completely different from what we see in temperate zones where, if an insect dies from a fungal infection, the game's over in a few days," Hughes said. "The fungi rots the body of the insect and releases massive amounts of spores over two or three days. But in the tropics, where humidity and temperature are more stable, the fungi has this strategy for long-term release."

Of the four new species, two grow long, arrow-like spores which eject like missiles from the fungus, seeking to land on a passing ant. The other fungi propel shorter spores, which change shape in mid-air to become like boomerangs and land nearby. If these fail to land on an ant, the spores sprout stalks that can snag ants walking over them. Upon infecting the new ant, the cycle starts again.

Chemicals from this global group of fungi, known as Cordyceps, have been a part of traditional medicine for thousands years, and part of Western medicine for the last 50.

Organ transplant patients, for example, receive ciclosporin — a drug that suppresses the immune system, reducing the chance the body will reject the new tissue. Chemicals from this same fungal group are also used for antibiotic, antimalarial and anticancer drugs.

The fungi help the forest by keeping ant populations in check. "All of the problems with global ant infestations, for example the Argentine fire ant," Hughes said, "is because the ants have escaped their natural enemies. Then they become a pest."

These fungi need a precise level of humidity to survive. As global temperature changes, the forests where they live are drying. Hughes and his colleagues are now studying the decline these fungi.

"We're worried we'll see the extinction of a species we've only just managed to describe."

On the following pages are more photographs of zombifying fungi in action.

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All images: David Hughes, Pennsylvania State University

See Also:

Citation: "Hidden diversity behind the Zombie-Ant fungus Ophiocordyceps unilateralis: Four new species described from Carpenter ants in Minas Gerais, Brazil." By Harry C. Evans, Simon L. Elliot, David P. Hughes. PloS One, Vol. 6 No. 3, March 2011.

An Unknown Ocean: The Other Rhythms of Life

Posted: 02 Mar 2011 03:41 PM PST

Circadian rhythms are well known to biologists, with hundreds of studies analyzing fundamental links between sunlight, cellular clocks, hormones and metabolism function.

But for the first few billion years of Earthly life, it wasn't just solar cycles that mattered. Lunar and tidal cycles were just as important, and for modern marine creatures they still are. Yet these cycles have received only a smidgen of scientific attention.

"When you look at the literature of circadian and lunar rhythms, they were equally prominent in the literature" until the early 1980s, said evolutionary neurobiologist Kristin Tessmar-Raible of Austria's University of Vienna.

That's when the first circadian clock gene was cloned in a fruit fly, allowing scientists to manipulate its function in a common model organism, and focus shifted. "Everything switched in modern molecular biology to what you could look at in fruit flies and mice. Those only have circadian rhythms," she said.

In a research review published in the March Bioessay, Tessmar-Raible and Florian Raible, a molecular biologist at the University of Vienna, describe the ubiquity of lunar and tidal cycles in ocean creatures, and the still-embryonic understanding of how those cycles work.

Their own interest was sparked several years ago in work on Platyneereis dumerilii, a marine worm known to evolutionary biologists as a living fossil, last sharing a common ancestor with vertebrates 600 million years ago. They found a previously unknown, light-sensitive cell deep in the worms' brains, far from any light.

Mystified at its location, they researched the worm's natural history, and learned that their wild spawning cycles occurred in time with lunar cycles. At conferences with marine biologists, Raible and Tessmar-Raible learned of a vast literature on animal behavior and lunar cycles.

'How many different clocks can you have? It's an open question.'

From algae to jellyfish to worms to crustaceans to mollusks to fish, examples abound of behaviors that change according to moon and tide. Molecular research is just beginning now, and questions abound. Raible and Tessmar-Raible's most basic question is how the lunar clock mechanisms work — and, indeed, how many different clock mechanisms there are.

"How many different clocks can you have? It's an open question," said Raible. "You can imagine that the inputs could differ between species. It doesn't have to be light. It could be the pressure of the water. This is all up for investigation. It's going to be very interesting to see and compare between species. It may be the same system, or there may be several independent systems that have evolved."

Another question is how lunar clocks don't interfere with circadian clocks, and vice versa. Yet another is whether land-dwelling creatures still have lunar clocks. It's not uncommon for complex terrestrial vertebrates to share features with ancient marine ancestors; in humans, female reproductive cycles may correlate with lunar cycles, though evidence is mixed.

However, Raible and Tessmar-Raible note that many other animals' reproductive patterns show no connection to the moon, and warn against speculation.

To them, understanding lunar cycles is less about investigating potential terrestrial analogues than coming to a deeper understanding of ocean creatures, which — despite humanity's landed perspective — dominate Earthly life.

"First we want to understand how these things work in organisms that really have lunar clocks, and see which molecules are involved," said Tessmar-Raible. "And then, are they really involved in vertebrates? Do we have them, and what are they doing? Let's see."

Images: 1) Frank van de Velde/Flickr 2) Phylogenetic chart of animals with lunar cycles. (Bioessays)

See Also:

Citation: "Another place, another timer: Marine species and the rhythms of life." By Kristin Tessmar-Raible, Florian Raible and Enrique Arboleda. Bioessays, Vol. 33 No. 3, March 2011.