Debilitating drought may have been a major factor in the fractious politics that ended the Maya civilization, according to archaeologists. Maya culture thrived in wet seasons and fell apart when the rains ceased. "It's an example of a sophisticated civilization failing to adapt successfully to climate change," said James Baldini, a professor at Durham University in the UK.

This claim is the result of new 2,000-year-old climate records from caves, a "war index" consisting of certain keywords in Mayan rock inscriptions, and archaeological data.

The decline and fall of the Maya is still a great mystery, and the role of climate change--specifically, drought--has been controversial in part because of the lack of data. To remedy this, Baldini and researchers from the U.S., Switzerland, Germany and Belize analyzed stalagmites from a Belizan cave called Yok Balum, which is located a little less than a mile from the Mayan site of Uxbenká. The icicle-like cave growths serve a little like tree rings, containing a record of past climates that can be cross-checked by uranium-thorium dating. Like radiocarbon dating, this method can determine the age of non-organic calcium carbonate material--in this case, cave limestone.

A 22-inch stalagmite from Yok Balum yielded measurements of oxygen isotopes, the research team explains in their paper. These isotopes can be used to reflect rainfall at any given time, falling above the cave and seeping in to form the stalagmite.

By analyzing this spiky protuberance, the team was able to identify broad cycles of wet and dry periods, as well an abrupt drought, in the era of Classic Maya (300 to 1000 C.E.). They argue that growth and expansion of Maya civilization correlates strongly with a wet period spanning several hundred years, archaeologist Douglas Kennett said in a podcast with the journal Science, which publishes the paper today.

"The decline of the Maya actually appeared to correlate with a downturn generally in climate, and climate drying, starting at around AD 660," he said. "We see an increase in warfare at this time, which we argue in the paper is linked to troubles in their economic system related to decreased productivity of their agricultural system."

The lack of moisture led to a lack of crops, which led to instability. Between C.E. 800-900, many cities fell. The team analyzed historical records inscribed on well-dated stone monuments to chronicle this collapse.

In this case, climate change is a natural cycle driven by something called the Intertropical Convergence Zone and by the familiar El Niño cycle. In El Niño years, the intertropical zone moves over the Pacific, and moisture in the Maya region decreases, the researchers say. Rainfall amounts impact agricultural productivity for good or ill.

"Many of the best-recorded ruling Maya lineages were founded around 440 to 500 C.E. during [an] interval of anomalously high rainfall," the authors say. And the opposite is also true. A drying trend started around 160 years later, in 660 C.E., with sporadic drought cycles lasting several decades. The early stages of this dry trend correspond with an increase in warfare among Mayan cities, the authors claim. Drought triggered balkanization and isolation, increased warfare, and generally destabilized Maya society, they say.

Drought is still just one factor, however. Archaeologists and anthropologists can now start studying its impact on the more complex human elements of the fall, Kennett said.

"It clearly played out over several hundred years, and climate plays one role in that decline, we argue," he said. "We're looking at climate as one part of a very complex system, and this is one of the foundational data sets for looking at these complex interactions in a much more detailed fashion."

The next stage is developing more sophisticated models that can reflect how climate influences society, he said.

In 1964, a lubrication expert named Peter Jost gathered with his colleagues at the Institution of Mechanical Engineers in Cardiff, Wales, to discuss a vexing paradox. Factory machinery everywhere was producing more and better goods than ever before. But it was also failing at an increasing rate. The immediate problem was friction: Lubricants were breaking down, bearings were wearing out, metal components were cracking. The larger problem was that plant managers did little to reduce that friction. A little grease, a little tinkering, nothing more. Why?

Jost and the other engineers decided the managers didn't know they needed help. Lubrication involved many disciplines-fluid dynamics, metallurgy, physics-and influenced every aspect of production, but most people overlooked it. So Jost set out to change the world's perspective.

He invented a new name for a new discipline, tribology, from the Greek tribos, or "rubbing." Tribologists would study "interacting surfaces in relative motion." Jost calculated that tribologists could reduce British manufacturing costs by 515 million pounds per year.

Soon tribologists were cutting costs around the world, and today they're involved in everything from making smoother hip socket replacements to predicting earthquakes by analyzing the stick-slip action of tectonic plates.

Managing friction saves more than money. It could even save the planet.And they're still changing our perspective, too. Last March, tribologists at Argonne National Laboratory and the VTT Technical Research Centre of Finland found that automakers could reduce inefficiencies in vehicles by 61 percent within two decades-simply by incorporating current tribological advances in, say, lubricant additives or surface coatings.

Like Jost, they put an annual price tag on that savings: more than $700 billion worldwide. But this time, they made an even more important point: The cars would burn 102 billion fewer gallons of gas per year, producing 960 million fewer tons of carbon dioxide. Managing friction saves more than money; it saves energy. It could even save the planet.

Multiply the efficiencies tribology could bring to the auto sector by the efficiencies it could bring to aviation, or shipping, or even just washing machines. Every barrel of oil we don't have to pump, every cubic meter of gas we don't have to frack, is a gain for the environment. By a simple shift of perspective, then, tribologists offer the ultimate form of alternative energy: a world with less friction.

Luke Mitchell (luke.mitchell@popsci.com) is the magazine's Ideas Editor.

BlackBerry has been having a rough go of it lately, slowly sliding into irrelevance as Android and iPhone corner the market. Now add one more nail to that coffin: a study says that people are allergic to BlackBerry phones. As in, an actual itch-inducing allergy. As in, to a phone.

The (strange, silly-sounding) study is being presented at the annual meeting of the American College of Allergy, Asthma and Immunology. Researchers looked at phones for two allergens, cobalt and nickel; about a third of BlackBerries had nickel, they found. The flip-phone models were worse: about 91 percent of those had nickel and 52 percent had cobalt. iPhones and Android phones, by comparison, didn't seem to have either allergen.

Researchers point out that this is a common allergy; about 17 percent of women and 3 percent of men get itching and swelling in their jaw line, ears, and cheeks when they come into contact with cobalt and nickel. But, come on, there's a lot of nickel out there, and it's not just in phones. These phones (especially the flip phones) have also been around for a while now without causing a dry skin pandemic. There are so many other good reasons for people to switch to iPhone or Android!

[EurekAlert]

Sight-reading complex musical notation takes years of training, hundreds or thousands of hours of practice, sitting in front of the piano, a metronome drilling its infernal clicks into your brain. Eventually you'll gain the ability to read and perform just about any piece of music that's set in front of you, without ever having seen it before. It does not come easily, and it is not a natural skill; you have to keep practicing to retain it. Each month you don't practice takes two months to earn back the power you've squandered. It is a human achievement, a way in which we force our brains and fingers and feet and eyes to perform a task we are not born able to do.

I was classically trained in piano for about twelve years, and this stupid little gadget has immediately negated all of my hard work.

The Gocen, created by a team at the Tokyo Metropolitan University, is a scanner which can read hand-written sheet music, interpret it, and play back in real time as you wave the scanner over each bar. It can even read words like "piano" and "guitar" to distinguish between instruments, or interpret which key the piece is in, and it decides volume based on the size of the note. Here's the little goblin in action:

I hereby pledge to destroy it. I will seize it from the Tokyo Metropolitan University lab and place it under my sustain pedal and I will play a Chopin Mazurka and stomp the sustain pedal at the beginning of every single bar until the Gocen is smashed into a thousand pieces. I will do this for every little six-year-old kid, his feet swinging beneath the piano bench because he is too tiny to reach the floor, straining to play "Ode to Joy," willing his fingers to be in the right places at the right times. I will win this fight for the humans.

[DigInfo]

As you wander through the Los Angeles County Museum of Art's sprawling new exhibit on Stanley Kubrick, it's hard not to marvel at how utterly distinct each of the legendary American film director's imagined worlds were: Lolita, Dr. Strangelove, A Clockwork Orange, <2001: A Space Odyssey, The Shining, Full Metal Jacket, Eyes Wide Shut, each a meticulously crafted cinematic cosmos unto itself. As Kubrick über-fan Steven Spielberg once noted, Kubrick was a chameleon who never made the made the same movie twice. What did stay constant, however, was his pioneering embrace of cutting-edge technologies, from Steadicams to NASA satellite lenses and more.

"In making a film, I start with an emotion, a feeling, a sense of a subject or a situation," Kubrick is quoted in the exhibit, his first U.S. retrospective. "The theme and technique come as a result of the material passing, as it were, through myself and coming out of the projection lens."

What a lens it was: Kubrick gave life to his haunting scenes and uncanny visions by constantly seeking out new tools that would explode earlier limits of what could be projected onscreen. Kubrick inspired new technological leaps in film, and new technological leaps inspired Kubrick. He was a relentless innovator and tinkerer, a point the LACMA exhibit makes by stuffing a 20-foot long case of some of director's beloved experimental lenses. His knowledge of still photography (he began his career shooting photos for Look magazine in his teens) traveled with him as he segued into film, and he found he could film exciting new perspectives by taking powerful still photography lenses and having them jury rigged onto traditional film cameras.

"Kubrick always reworked his material and mise-en-scène so that the technology became essential to the telling of the story and this defines his relationship to innovation," says Patti Podesta, a Hollywood production designer who's worked on films such as Memento and Bobby and designed the LACMA installation. "He sought out new technologies but also had a kind of technological patience, the discipline to wait until innovation caught up to his imagination." Check out the gallery above for a look at some of Kubrick's signal advances.

Stanley Kubrick runs at LACMA until June 30. More information here.

Before you sell, donate, or recycle your old computer, beware: You may be handing personal information to strangers. Simply restoring the operating system to factory settings does not delete all data and neither does formatting the hard drive before reinstalling the OS.

To really wipe a drive clean, users will need to run secure-erase software. For Windows, the best bet is the command-line utility SDelete (free), which writes over the space on the drive. SDelete runs from any bootable disk or from the hard drive of another computer connected with a device such as the Universal Drive Adapter ($39.99). Linux users can try the Shred command, which overwrites files in a similar fashion.

On a Mac, the Erase command included with the Disk Utility application securely erases drive contents. As with SDelete, first delete files from the drive, then use the erase free space feature. It offers three options, from fastest, which writes zeros over unused disk space, to most secure, which overwrites the drive at least seven times. The middle setting is probably secure enough for most home users.

There is, of course, one other foolproof way to render data unrecoverable: Drill two to three holes with a quarter-inch drill bit through the drive platters.

Got a question? Send it to us at H20@popsci.com

I learned how to cook the day I opened my first issue of Cook's Illustrated. Phrases like Maillard reaction and gluten development and Best Blueberry Pancakes flowed across pages adorned with desaturated sketches, drawing me in with their simplicity and forthrightness. This is the best way to grill salmon or make pie crust, the articles said--and here are three pages of reasons why.

CI brought the scientific method to cooking: Take a hypothesis, test it, see if it comes out like you expect, and learn from it, improving your method next time. If a recipe doesn't work, adjust it. And don't worry about buying artisan bread and hand-cutting your hydrangeas to fit individual bud vases--that's pretentious. Compared to other glossy food magazines, this was a revelation.

This excellent, recent New York Times profile of editor Christopher Kimball--a must-read for CI fans--will give any reader some insight into their methods. For most Americans, cooking is not about art, but about dinner, Kimball firmly believes. Sustenance. Success is often hard-won, dependent on, yes, some flair and some skill, but also on some basic knowledge of what heat and force can do to edible things. Now Kimball and his staff have distilled 50 of these basic rules into a new cookbook, "The Science of Good Cooking." I think this is a great idea. Like knowledge of baking ratios, understanding the science behind cooking will free you from following recipes and allow you to be creative.

To be clear, Modernist Cuisine it is not--this book contains several very basic concepts and no liquid nitrogen. But if, like me, you are curious about chemistry and protein denaturation but have no idea how to achieve whirled peas, you'll enjoy it.

To test its kitchen utility, I made three things that I already make (occasionally using variations on existing CI methodology), but I made them according to this new cookbook's strictures, keeping their intended lessons in mind. Here's how they turned out.

Scrambled Eggs

Lesson: Fat Keeps Denatured Proteins Together

Scrambled eggs are arguably one of the easiest things to truly cook, if you use that definition to mean changing the structure of a food. You can scramble eggs in the microwave! (But you shouldn't.) Yet there is a technique behind truly great scrambled eggs.

The America's Test Kitchen method: Along with gentle beating and pre-salting, use extra fat. The book recommends adding an extra yolk, which adds an extra helping of lipids to your mixture. Then add half and half, not milk, for the same reason--the fat in the milk coats the proteins in the egg white and yolk, preventing the loss of too much liquid and yielding light, fluffy eggs. Also, cooking over low heat is key.

To make one serving, I beat two large eggs plus one yolk with a tablespoon of half and half, and a pinch of salt and pepper. I melted a quarter tablespoon of butter in a medium-high skillet and added the eggs, swirling them in the pan for about 90 seconds.

Did it work?
The eggs were tender and silken, a lovely goldenrod mass glistening with butter. It looked and tasted great--but it was ultimately too heavy for my taste. I think of scrambled eggs as a fairly healthy breakfast, but this adulteration made it seem like a sin, like it coated my insides for a day. I don't think I would add the extra yolk again. But the half and half ... probably.

Banana Bread

Lesson: Minimize Gluten And Up the Banana Flavor

Quick breads like banana bread and muffins are supposed to be tender and cakey but not chewy, which requires minimizing the development of gluten. Fats and sugars prevent gluten formation by interfering with protein folding. But you create it when you mix the batter, a necessary step to combine wet and dry ingredients. As the book puts it, it's more what you don't do that matters.

Even with a gentle touch, though, banana bread can be way too dense, a function of the relatively large amount of bananas you need to achieve great banana-y flavor. I usually smash bananas with a fork, stir them with the eggs and fat, and then add them to the dry ingredients. ATK has you do far more work--you have to microwave the bananas so they release their liquid, strain them for 15 minutes, then reduce the liquid in a saucepan until you have 1/4 cup of super-concentrated banana juice. This is added to the banana pulp, melted butter, brown sugar and eggs, keeping the liquid ratio correct, then it's mashed with a potato masher.

Did it work?
Yes! This was far better banana bread than my usual, which includes some vegetable oil and white sugar instead of only butter and brown sugar. That alone was an improvement. But zapping the bananas in the microwave, something I would never have thought to do, yielded a dramatic difference. The loaf had more banana flavor, yet it wasn't dense; it was still cake-like and fluffy. I would definitely make this again.

Flank Steak

Lesson: Give All Meat a Rest

A lean, thin slab of flank steak is supposedly one of the humbler cuts of beef, lacking the marbling and texture of a strip or any number of more expensive cuts. But it can still be juicy and tender when handled properly. I almost always marinate a flank steak, which improves it in two ways: Marinades inject their own flavors, and salting the meat (and the marinade) changes the muscle proteins, tenderizing them and drawing out moisture.

The recipe I wanted to test called for no marinade at all, no scoring and no brining. The entire success of the dish relied upon a lengthy rest once it came off the grill. I used cumin, chili powder, coriander, red pepper flakes, salt and pepper and a secret ingredient--cinnamon--and rubbed it all over the 2-lb steak. I preheated the grill for 15 minutes, like the recipe said, and threw the steak on for five minutes on one side, and three on the other. Then I brought it inside and ignored it for 10 minutes before slicing against the grain.

Did it work?
I think my grill was too hot, and the steak cooked more quickly than it should have--the edges were too dry after a short cooking time. But the center was still a dark pink, and the crust was delicious. I'd probably make it again, if only because I usually forget to marinate steak and don't feel like waiting--and this is a very tasty, easy alternative.

Bottom Line: Trust Science

I'm clearly a fan of Cook's Illustrated, so perhaps you should take all of the above with a fat grain of kosher salt. But forget about your favorite cooking style or celebrity chefs or foodie fads, and we can agree that cooking really is a science, with predictable outcomes based on initial conditions. Understanding the rules underlying those outcomes--which this book does very well--will make you a better cook.

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Carl Sagan, everyone's favorite late astronomer, would have been 78 today. We can't think of anyone who inspired so many people to love science and the universe than good old Sagan. This year, we're looking back to an interview with the scientist that appeared in our September 1972 issue. At the time, he was really stoked about Mars.

At the time of publishing, the scientific community was trying to figure out just what Mars was like, and photos from the Mariner 9, a NASA space orbiter, had recently revealed that the red planet was completely different than we thought. The scientific community decided that Mars was a dead planet, but the photos showed evidence of high winds, dust storms, massive geological craters that would rival the Grand Canyon, and the possibility of running water. PopSci turned to Carl Sagan to explain these exciting new findings.

Sagan told us the Mariner 9 photo results he found most significant were evidence of changes due to windblown dust, evidence of volcanic activity, evidence of running water and recession of polar caps. These findings are now coming full circle as the Curiosity rover gets up close and personal with the Martian terrain. It only took some 40 years.

Though many thought that conditions on the red planet--including low night temperatures and lack of atmospheric oxygen and ozone--were too harsh to support life, Sagan begged to differ. According to his research, microorganisms did have a chance for life on Mars. Here's what he said on the subject:

Sagan also believed there could have been water on Mars as recent as 100 years before the interview:

If only Carl Sagan could see what we're doing on Mars now! He died in 2006 in Seattle, but perhaps he would've been really excited to know that a rover was giving itself dust baths on a nearby planet.

Read the full story in our September 1972 issue: Close Up Photos Reveal A Turbulent Mars.

Want to win this paranoid Baarbarian illustration on a T-shirt? It's easy! The rules: Follow us on Twitter (we're @PopSci) and retweet our This Week in the Future tweet. One of those lucky retweeters will be chosen to receive a custom T-shirt with this week's Baarbarian illustration on it, thus making the winner the envy of friends, coworkers and everyone else with eyes. (Those who would rather not leave things to chance and just pony up some cash for the T-shirt can do that here.) The stories pictured herein:

• How I Hacked An Electronic Voting Machine
• Scientist Wants To Fly A Blimp Over Mountains To Search For Bigfoot
• Why Can't We Vote By Email Or Text?

And don't forget to check out our other favorite stories of the week:

• Archive Gallery: The Science Of Elections
• Did Your Team Win Monday Night Football? And 9 Other Weird Questions That Reveal How You'll Vote Today
• Thank You, Bravo, For 'Start-Ups: Silicon Valley' [Review]
• Dear President Obama: Congratulations! But We Need To Talk.
• Why Do Computer Scientists Want Election Day To Drag On For A Full Week?
• Why Can't We Stop A Hurricane Before It Hits Us?
• This Is Why Nobody Will Use Credit Cards In A Few Years
• BeerSci: How To Make Beer Foamier
• How The Evil Tech In James Bond Films Evolved Alongside Real-World Fears
• How The Science Of Tribology Could Smooth The Way To A Better Energy System
• 8 Of Stanley Kubrick's Greatest Technological Innovations
• Your Scrambled Eggs Are Wrong, And Other Cooking Science Lessons From America's Test Kitchen

This week, as a companion to Popular Science's November issue, we're bringing you a bunch of stories about materials science--a field that touches on all aspects of of the world around us, from the paint on our walls to the the drugs that treat our diseases. Swing by for an exploration of some of the most dangerous materials in your home; a taste of what famous buildings might've looked like had materials scientists known what they know today; and a snapshot of nanomaterials as you've never seen them before. All that and more can be read here on PopSci.com, starting today. Enjoy!

Failure is supposed to be a bad thing. In materials science, however, understanding and predicting how a new fiber, composite material, or type of plastic breaks, snaps, melts, fractures, or rips can mean the difference between life and death. Engineers need to know if an armored steel plate will stop a high-velocity bullet or whether a specialized car-seat foam will effectively absorb the impact of a crash.

Destructive testing can also help scientists figure out how to enhance a given material's properties, as with composites for aircraft wings or polymers used in electronics. Across the U.S., dozens of labs concoct elaborate and sometimes genuinely perilous tests in the name of safety and knowledge. PopSci spoke with materials scientists, CEOs, and researchers to find four of the most extreme labs in the nation.

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Everyone knows the hardest material on Earth is diamond, says George Pharr, director of the Joint Institute for Advanced Materials at the University of Tennessee. But when it comes to the softest stuff on the planet, "there's no one definition," he says.

Metallurgists and mineralogists might interpret "softness" to mean a material's tendency to deform under pressure and to stay in that deformed state. But that reading might come off a little wonky when you start looking at elastic materials, like rubber, which can deform and then regain their form.

As a result of this ambiguity, researchers employ an array of hardness (or softness) tests, depending on what sort of material they're looking at. For minerals, they might use the classic (and exceedingly simple) Mohs assay, which involves rubbing one material against another to see which one gets scratched. According to the Mohs scale, talc, also known as soapstone, is the softest mineral; it is composed of a stack of weakly connected sheets that tend to slip apart under pressure.

When it comes to metals, scientists try to measure hardness in absolute terms. They press a ball- or pyramid-shaped bit into the material in question at a predetermined pressure and over a set period of time. Researchers then measure the dent left behind. The hardness of a metal, Pharr says, depends on the fraction of its bonds that happen to be covalent; these are strong, stable arrangements in which atoms share a pair of electrons.

Pliable metals like gold have fewer of these bonds than tougher materials like molybdenum and tungsten. Highly reactive metals with low melting points, such as cesium and rubidium, end up at the very softest end of the spectrum. Pharr warns that any attempt to pick out the absolute softest material, however, "would be subject to debate."

Have a burning science question you'd like to see answered in our FYI section? Email it to fyi@popsci.com.

Images are fundamental to science. Biologists use X-rays to study the fine structure of plants, and astronomers take pictures with the Chandra telescope to probe the dynamics inside of exploding stars. When it comes to places where no camera can look, scientists create images from the information available: geologists use seismic data to build charts, diagrams and simulations of the deep Earth churning.

As a nod to the importance of images in science--both those taken with cameras and those constructed from data--the National Science Foundation holds a competition every year for the best visualization in science. The entries never disappoint.

Take a look at some of our favorites from this year's competition here, and then go vote for your favorite--today is the last day to vote!

Before we can construct the realistic humanoid robots that populate our most vivid sci-fi-driven dreams, there are a lot of human systems that researchers are going to have to emulate synthetically. Not the least challenging is human skin; filled with nerve endings and able to heal itself over time, our skin serves as both a massive sensory system and a barrier between our innards and the outside world. Now, an interdisciplinary team of Stanford researchers has created the first synthetic material that is both self-healing at room temperature and sensitive to touch--a breakthrough that could be the beginnings of a new kind of robot skin (and in the meantime enjoy much more practical applications like enhanced prosthetics).

The Stanford material is far from the first self-healing plastic or polymer, but it does enjoy some benefits that set it apart. For one, many self-healing materials require some kind of catalyst or special condition to heal up, things like exposure to high temperature or certain spectrums of light. Others can heal up at room temperature, but they generally can only do so once--the act of healing alters their chemical structure such that they cannot do it a second time, much less a third or fourth.

Then, if an analog for skin is what you're truly looking for, there's the problem with touch sensitivity. Most plastics, polymers, and such--the primary materials used in self-healing research--are fantastic insulators. But to imbue a material with a sense of touch--and to make it interface with a larger digital system--you really want something conductive. That's where the Stanford team has really broken new ground. Its material can repair cuts or tears in itself at room temperature multiple times, and it is conductive.

How did the researchers pull it off? They started with a plastic consisting of molecular chains joined by simple hydrogen bonds. This imparts the self-healing ability, as the bonds can be easily broken but also easily reconstituted by simply putting the broken chains back in contact with each other. In the lab, the researchers severed a piece of the material completely, creating two separate halves. After pressing the cut edge back together for just a few seconds, three-quarters of its prior strength had been restored. Within half an hour it returned to nearly 100 percent strength. After 50 such trials, the material still healed up nicely.

Then, to achieve conductivity, the researchers distributed nickel particles throughout their plastic. These nickel particles not only increase the material's mechanical strength, but also serve as a means for electrons to move through the material, hopping from one particle to the next, creating an electric current. Bending, flexing, or otherwise warping the material changes the distance between the nickel particles, altering the material's resistance to the current. That electrical resistance can be measured to determine the shape of the skin and any pressure being exerted on it.

It's easy to envision something like this being integrated into future prosthetics to help restore a sense of touch to those missing a limb. More immediately, such a material could be used to sheathe other electronics to give them a self-healing capacity. The findings were published in the November 11 issue of the journal Nature Nanotechnology.

[Stanford Engineering]

A big step forward in invisibility cloaking today: Researchers have pulled off the first-ever "perfect" cloaking of an object, rending a small cylinder completely invisible while creating absolutely no reflections of incident light that might give the concealed object away. The catch? The object was centimeter-scale, and the cloaking was done in the microwave spectrum rather than in visible light. Your invisibility cloak is still on hold.

But that doesn't make this any less of a breakthrough where metamaterials and cloaking are concerned. Many attempts at cloaking have been made, and many have been some degree of successful. But the original theory that led to all this cloaking science says that we should be able to cloak objects entirely, and up to this point we've failed to do that. Every other attempt has, to some extent, left behind small reflections of incident light.

That means that even though those materials successfully bent light waves around the target object to make it appear invisible, they still didn't perfectly translate the light from behind the object to the space in front of the object--had these attempts happened in the visible spectrum, the space concealing the object would've appeared dark or discolored or otherwise not quite right.

This stuff is of course quite complicated and these kinds of cloaking materials can be extremely expensive and difficult to produce, but nonetheless a Duke University team has managed to create what it believes is the first cloak that achieves perfect invisibility by concealing a one-centimeter-tall cylinder from microwave detection without any incident reflections.

The trick: a diamond-shaped material cloak that was extremely finely tuned at the diamonds corners to ensure the light bent perfectly around the object with no aberrations. The catch: this cloak only works from one-direction, and would be really difficult to replicate in the visible spectrum. Still, it's a milestone and a step forward for the discipline; microwave cloaks could be important in future communications and defense applications, as the world around us is not tuned strictly to the visible spectrum.

[BBC]

The goofy Samsung Galaxy Camera--a point-and-shoot with a 4.8-inch touchscreen and a full version of Android--came out of nowhere and actually impressed us. The interface is fast and efficient for changing settings, the screen is great, and the camera has some pretty decent optics to book (21x optical zoom lens, 16MP CMOS sensor). And we just got an email from AT&T telling us the camera will cost $499.99, either with or without a 4G data plan. Yoooouch. That's even more than the $450 Canon S110, the reigning champ of advanced compacts. We'll have a full review soon so you can see if it's worth it.

Proof that video games keep getting more and more realistic: Seven U.S. Navy SEALs, including one who participated in last year's raid that killed Osama bin Laden, have been disciplined by the Navy for divulging secrets while serving as consultants for the new Medal of Honor: Warfighter video game released by Electronic Arts. The Navy hasn't said exactly what secrets the two Senior Chief Special Operators and five Chief Special Operators exposed, but the seven were charged with violation of orders, misuse of command gear, dereliction of duty, and the disclosure of classified information. Each received a reprimand letter and had his pay docked by half for two months.

[BBC]

The latest TOP500 rankings of the world's fastest supercomputers is out today, and as expected Oak Ridge National Laboratory's Titan has unseated Lawrence Livermore National Laboratory's Sequoia in for the number one seat. That means a couple of things. For one, it represents something of a proving out for co-processor technology (that's technology that uses graphics processors alongside conventional processors to accelerate a machine's performance), which drove Titan's performance over the top. Secondly, it means it's been a really good year for American supercomputing.

Titan is the successor to ORNL's Jaguar supercomputer (actually, it's really an upgrade of Jaguar), which itself sat atop the TOP500 rankings a few years ago. Since then, computers in China, Japan, and elsewhere have really given the U.S. a serious run for its money, unseating Jaguar for the number one position and pushing other systems down the rankings at times. For ORNL and the U.S. Department of Energy, it has to be nice to have two separate systems sitting in the top two spots on the TOP500.

But more significantly, today's rankings demonstrate that hybrid processing--using graphics processing units (GPUs) to augment the central processing units traditionally deployed in supercomputers--could be the real way forward for supercomputing, at least in the near term. Titan officially recorded speeds of 17.59 petaflops (that's quadrillions of calculations per second), yet the entire computing apparatus fits into the same 200 server cabinets as the 2.3-petaflop Jaguar. That's because GPUs are better at some kinds of operations that CPUs aren't necessarily so good at--especially operations that involve more parallel kinds of computing. By coupling NVIDIA Tesla GPUs with 16-core AMD CPUs, the engineers at Cray that built Titan for ORNL were able to increase computing performance by a factor several times greater than its increase in energy consumption (or size).

That's very important going forward. The goal across the globe right now is to develop an exascale machine (an exaflop is equivalent to 1,000 petaflops--so we have a ways to go), and the U.S. is trying to do so on a budget. So proving that GPU augmented machines can outperform the very best supercomputers in the world could mark the beginning of a sea change in the science and engineering of supercomputing.

Right now, 62 systems on the TOP500 list are accelerated in this way, including China's Tianhe-1A, which sat atop the list back in 2010 but now ranks number eight. That's up from 58 systems six months ago, and the number is likely to continue growing. The time may soon be upon us when it's simply unfeasible to compete for the top 10 or even the top 25 systems in the world without leveraging some kind of acceleration technology, and that's probably a good thing. More efficient methods of crunching more data are what will lead us to the exascale age--a scale at which many computer scientists think things will get really interesting.

Rounding out the top five: Japan's K Computer at number three, Argonne National Laboratory's Mira (which will soon begin running the world's largest cosmological simulations), and Germany's JUQUEEN, which is now Europe's most powerful system after a recent upgrade. On top of the aforementioned three in the top five, America has two more machines in the top 10--placing half of the fastest ten computers in the world within the U.S. We'll take it.

The next rankings will be released in June of 2013.

Bodily fluids are not the first thing that come to mind when you're looking for a disinfectant. But mucus is surprisingly good at preventing bacterial growth--never mind that it's a nasty side effect of infection on its own. A type of polymer found in mucus--known as mucin--can trap bacteria and prevent them from clumping together into a hard-to-remove biofilm, MIT scientists say.

Biofilms are the bane of hospitals' existence, because they consist of large colonies of bacteria living in slimy layers that can be very difficult to eradicate. Mucus protein can help. It makes a lot of sense when you think about it: Mucus is a defensive mechanism, protecting our noses, mouths, eyes and other membranes from would-be invaders. The thing is that no one has been sure just how this infection barrier works, according to MIT News. Former MIT postdoc Marina Caldara and current grad student Ronn Friedlander published a paper last week in Current Biology that observed the behavior of a bacterium in response to mucus proteins.

The mucins are long protein chains with lots of sugar molecules, which keep bacteria from moving around and clustering together. This can prevent infection--a takeover by bacteria--and it can prevent biofilm formation, the researchers found. This is different from previously held theories of how mucus works--it doesn't grab onto foreign particles and trap them. Instead, the bacteria are simply suspended in the gooey gloop of mucus, where they can do less damage as individuals than they might as a collective.

The team is now studying how mucus proteins could be integrated into antibacterial products, from toothpaste (!) to protective coatings.

[MIT]