What’s the News: The world’s population is projected to reach 7 billion this October and continue climbing, reaching 10.1 billion by the end of the 21st century, says an official United Nations report (PDF) released earlier this week. This is a significant departure from earlier projections that said the population would peak at just over 9 billion, then level off and even slightly decline.

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What’s the News: Quantum effects like entanglement and superposition are surpassingly strange, and also impossible for humans to see, occurring as they do at the level of subatomic particles. But now researchers have set up an experiment that makes the effects of quantum entanglement visible to the naked eye—at least in theory.

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What’s the News: A group of physicists say they’ve found a way to account for the mysterious radio signals that may be emanating from colonies of E. coli—and it’s not because they’re trying to get our attention.

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A new model of crowd behavior uses simple visual rules.

What’s the News: When crowds go wrong, they go really wrong—more than 300 people died in a stampede in Cambodia last year during a festival, and hundreds more have been crushed to death in periodic disasters near the Muslim holy city of Mecca. A major flaw of computational models describing how people behave in crowds is that they are often too simplistic or too specific to a situation to explain both normal and disastrous behavior. A new model manages to recreate both types of behavior, working from two basic visual rules: (1) each person will move in the least crowded direction in their line of sight, and (2) they will adjust their speed to maintain a safe distance from visible obstacles.

“This work is an extremely important step in pulling together our fragmented understanding,” says behavioral biologist Iain Couzin, who was not involved in the study (via ScienceNOW). “We’re now approaching a sort of unified understanding of human behavior in crowds.”

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What’s the News: Japan raised its assessment of the severely damaged Fukushima Daiichi nuclear power plant to Level 7, “Major Accident,” the highest ranking on the International Atomic Energy Agency’s International Nuclear and Radiological Event Scale. The explosion at Chernobyl in 1986 is the only other nuclear accident to be ranked at Level 7. Both accidents were extremely severe, the two largest nuclear power accidents ever—but there are some big, important differences between them.

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What’s the News: On a quest to discover at what size the kooky quantum physics that governs atoms (teleporting!) gives way to the ho-hum classical physics that governs humans (no teleporting), scientists have shown that if conditions are right, a molecule of a record 430 atoms can be in two states at once, like Schrödinger’s infamous cat. For the last three decades, researchers have been watching progressively larger objects under special conditions to see how big of an item they can catch showing quantum behavior. This molecule, which was created by a team at University of Vienna and their collaborators for the experiment, is the largest on record.

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What’s the News: Cool new apps come out every day, but not every app comes with its own car service. Starting in San Francisco, one company lets pedestrians hail a car using their iPhone or Android phone (or any old text-messaging clunker), providing a more expensive, yet faster alternative to cabs. To make this possible, computer scientists had to find a way to make driving routes as efficient as possible, which is actually quite complicated when you’re dealing with a city-ful of car-hailing people. As Uber CEO Travis Kalanick told Wired, “It’s really fun, sexy math.”

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In the future, nuclear clean-up workers may be getting help from some surprising sources. None of these three methods are in widespread use right now, but they show promise:

1) Algae

• Scientists have discovered that a type of algae can precipitate strontium into crystals. This could lead to better nuclear clean-up techniques, potentially sequestering radioactive strontium-90 from tainted water into crystalline form, which is easier to contain.
• The algae, called C. moniliferum, collects strontium in sulfate-rich vacuoles, and because strontium and barium have low solubility in sulfate solutions, they precipitate out of solution as crystals.

What’s the Context: The danger of strontium-90 is that it is chemically similar to calcium, and so can be taken up into milk, bones, and other tissues. Nuclear waste and spills can contain significant amounts of strontium; C. moniliferum is especially helpful because it can precipitate strontium but leave calcium alone (calcium is different enough from barium that the bacteria doesn’t crystallize it).

Not So Fast: Scientists don’t yet know how well the algae can withstand radioactivity, which could potentially put a damper on this clean-up method. Now, the scientists would like to find ways of increasing sulphate levels in the environment, which may in turn increase the ability of the algae to crystallize strontium.

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Reactor 3 at the Fukushima Daiichi plant, on March 24

What’s the News: A non-peer-reviewed study (pdf) publicized last week by radioactivity-detection expert Ferenc Dalnoki-Veress suggests that nuclear fission reactions continued at Japan’s Fukushima nuclear power station well after the plant’s operators had allegedly shut down the reactors there. The paper says there may be what are called “localized criticalities” have occurred in the plutonium and uranium left in the reactors—little pockets of fuel that have gone critical, propagating the nuclear chain reaction and generating potentially harmful radiation. The existence of criticalities is controversial: some researchers say there are certainly none; Dalnoki-Veress himself says it’s only a possibility.

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Fiordland National Park in New Zealand, the location of the study

What’s the News: Researchers have mapped out the detailed geological history of a 300-square-mile chunk of New Zealand, from 2.5 million years ago to the present day. The study showed how glaciers carved out the area’s distinctive valleys using a little-known technique called thermochronometry, which involves shooting proton beams onto rocks and making note of what happens—along with some impressive analytical skills.

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• While modeling plasma flows deep inside the sun, scientists may have found an explanation for why some sunspots cycles (like the most recent one) are weaker than others. “It’s the flow speed during the cycle before that seems to dictate the number of sunspots. Having a fast flow from the poles while a cycle is ramping up, followed by a slow flow during its decline, results in a very deep minimum.”
• Risky business: In defending President Obama’s vision for space exploration that relies upon commercial space companies, NASA administrator Charles Bolden says the country must “become unafraid of exploration. We need to become unafraid of risks.”
• Bad timing: Just as Apple unveils its new iPad—and Steve Jobs uses the opportunity to gloat about his company’s superiority in apps compared to Google’s Android system—Google had to take 21 apps off the Android Market because they were infected with malware.
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Modern microscopes opened up the world of the minute to an amazing degree, allowing people to see all the way down to a bacterium wriggling on a slide. But if you want to see down even smaller in regular optical light—to a virus, a cell’s interior, or other objects on the nanoscale—you’ve been out of luck. Those objects are smaller than 200 nanometers, what’s been considered the resolution limit for microscopes scanning in white light, and so the only was to see them was through indirect imaging devices like scanning electron microscopes.

Not anymore. Lin Li and colleagues report a new way using tiny beads to resolve images at 50 nanometers, shattering the limit for what can be seen in optical light.

Their technique, reported in Nature Communications, makes use of “evanescent waves“, emitted very near an object and usually lost altogether. Instead, the beads gather the light and re-focus it, channelling it into a standard microscope. This allowed researchers to see with their own eyes a level of detail that is normally restricted to indirect methods such as atomic force microscopy or scanning electron microscopy. [BBC News]

Those beads are called microspheres—they’re tiny glass balls about the size of red blood cells. The researchers apply these spheres to the surface of the object they want to see. In essence, the spheres capture light that normally would be lost before it ever reached the observer’s eye (those evanescent waves), enabling Li’s team to overcome the diffraction limits of microscope machinery that have limited the maximum possible resolution.

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From across the pond comes a ravishing collection of scientific imagery. The Wellcome Collection, a London museum, has just announced the winners of its Wellcome Image Awards.

The 21 award winners, selected from images acquired by the Wellcome Collection over the last 18 months, were chosen both for their ability to enhance scientific understanding and for their aesthetic appeal. Many use colour to better illustrate hard-to-see features. [New Scientist]

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Sandfish lizards jostle back and forth, bending their bodies into a slithery S-curve to swim through the sands of the Sahara. Like scorpions and several other native desert species, they long ago mastered the difficult art of moving through the myriad grains of a sandy expanse to escape predators or the blistering African sun. And now physicists are close to cracking their secrets.

Daniel Goldman’s team has been trying to figure out just how the sandfish lizards do it for years now; in 2009 they built a robot to simulate the creature’s slithering motion. This time, for a study in the Journal of the Royal Society Interface, the scientists tried to model the physics of an animal knocking around so many grains of sand and see how the lizards burrow with such efficiency.

The team found sine-wave-like movement allows the lizard, and their robot, to push forward in sand, but creating computer models for the experiments proved problematic. Simulating all of the tiny sand grains required a lot of money to purchase time on powerful computers. So, the team performed the same experiments using 3-millimeter-wide glass beads instead of sand. “We wanted something easy to simulate that had some predictive power. We got lucky, because it turned out [the lizard and robot] swim beautifully in the same way through larger glass beads,” Goldman said. [Wired]

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The anti-laser—a tech with such a cool name it doesn’t need an obvious application—first came to our attention last year when Yale’s A. Douglas Stone proposed the idea. Now Stone is back with the real thing. His new paper in Science documents the world’s first anti-laser.

Conventional lasers create intense beams of light by stimulating atoms to spit out a coherent beam of light in which all the light waves march in lockstep. The crests of one wave match the crests of all the others, and troughs match up with troughs. The anti-laser does the reverse: Two perfect beams of laser light go in, and are completely absorbed. [Wired]

Anti-lasers are a bit of a funny concept, because anybody who has worn black on an August afternoon knows that absorbing light and turning it into heat isn’t a problem. But creating a device that matches the concentrated beam of a laser and traps more than 99 percent of it—essentially reversing a laser—is an engineering feat.

Whereas a laser uses mirrors to bounce light back and forth through an amplifying material to concentrate it, the anti-laser, as the name would suggest, does basically the opposite.

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