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80beats

Archive for the ‘Physics & Math’ Category

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Rising Sea of Humanity: UN Says Pop. Will Hit 10B by 2100—& Keep Going Up

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.

(more…)

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May 6th, 2011 Tags: Africa, demography, fertility, mortality, population, United Nations
by Valerie Ross in Living World, Physics & Math | 17 Comments » | RSS feed | Trackback >

Have People Seen Quantum Entanglement With the Naked Eye? It’s Complicated

photons

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.

(more…)

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May 3rd, 2011 Tags: entanglement, quantum physics
by Veronique Greenwood in Physics & Math | No Comments » | RSS feed | Trackback >

Could Bacteria Communicate by Bouncing Electrons Around Their Chromosomes?

e coli

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.

(more…)

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April 25th, 2011 Tags: bacteria, bacterial communication, radio waves
by Veronique Greenwood in Physics & Math, Uncategorized | 15 Comments » | RSS feed | Trackback >

Visual Virtual People: A Better Model for the Behavior of Crowds

crowds
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.”

(more…)

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April 25th, 2011 Tags: computational models, crowds, human behavior, PNAS, senses, stampedes
by Veronique Greenwood in Mind & Brain, Physics & Math | No Comments » | RSS feed | Trackback >

Fukushima and Chernobyl: Same Level on Disaster Scale; Very Different Disasters

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.

(more…)

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April 14th, 2011 Tags: Chernobyl, disasters, Fukushima Daiichi, nuclear reactor, radiation
by Valerie Ross in Environment, Physics & Math, Top Posts | 7 Comments » | RSS feed | Trackback >

Researchers Find “Fattest Schrodinger Cats Realized to Date”

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.

(more…)

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April 7th, 2011 Tags: quantum mechanics
by Veronique Greenwood in Physics & Math | 20 Comments » | RSS feed | Trackback >

“Sexy Math” Helps App Amp Up Car Services

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.”

(more…)

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April 5th, 2011 Tags: computers, gadgets, math, Technology, transportation, traveling-salesman problem
by Patrick Morgan in Physics & Math, Technology | 1 Comment » | RSS feed | Trackback >

3 Creative Tools for Nuclear Cleanup: Algae, Rust, and Bacteria

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.

(more…)

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April 5th, 2011 Tags: algae, bacteria, nuclear energy, nuclear waste, rust
by Patrick Morgan in Environment, Physics & Math | 6 Comments » | RSS feed | Trackback >

Study: Nuclear Fission Reactions May Have Continued After Fukushima’s Alleged Shutdown

Fukushima Daiichi Reactor #3
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.

(more…)

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April 4th, 2011 Tags: earthquake, Fukushima Daiichi, japan, natural disasters, nuclear energy, nuclear reactor, tsunami
by Valerie Ross in Environment, Physics & Math | 7 Comments » | RSS feed | Trackback >

Ingenious Geological Sleuthing Reveals the Shapes of Ancient Mountains

Fiordland National Park
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.

(more…)

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April 2nd, 2011 Tags: chemistry, earth science, Fiordland National Park, glaciers, helium, helium-3, isotopes, New Zealand, research techniques, Science (journal), thermochronometry
by Valerie Ross in Environment, Physics & Math | 1 Comment » | RSS feed | Trackback >

News Roundup: Why the Sun Lost Its Spots

  • 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.
  • (more…)
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March 3rd, 2011 Tags: Apple, california, Google, iPad, NASA, Parkinson's, roundup, sun
by Andrew Moseman in Journal Roundup, Physics & Math, Space | 5 Comments » | RSS feed | Trackback >

Using Tiny Glass Spheres as a Superlens, Microscope Shatters Resolution Record

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.

(more…)

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March 2nd, 2011 Tags: bacteria, cells, light, microscopes, viruses
by Andrew Moseman in Physics & Math, Technology | 2 Comments » | RSS feed | Trackback >

Finding Art in Science: See the Dazzling Winners of the Wellcome Awards

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]

This is the embryo of a cavefish at the age of five days. The glowing green (achieved by injecting an antibody against a calcium-binding protein) reveals the taste buds and nervous system.The <a href="http://en.wikipedia.org/wiki/Great_diving_beetle" target="_blank">great diving beetles</a>, the largest freshwater beetles in the U.K., have a problem--when you spend your time in the water, it's difficult to grip anything. As a solution, the male beetles possess these "suckers" on their forelegs and use them to hold onto females during mating.A honeybee revealed in close-up false color by scanning electron micrograph. For an even closer look at how a bee is built, check out DISCOVER's photo gallery <a href="http://discovermagazine.com/photos/18-alluring-alien-sights-of-bee-ultra-close-up" target="_blank">The Alluring and Alien Sights of a Bee in Ultra Close-Up</a>.As revealed by scanning electron micrograph, the wing of the superbly named Madagascan moon moth is covered in tiny scales.<br /><br />
<p style="padding-left: 30px;">It has spectacular wings and is also known for its long tail. As a result, it is also called the comet moth. The moon moth also has no mouth parts; all feeding is done in its caterpillar stage, which means it only lives ten days. [<a href="http://www.telegraph.co.uk/science/picture-galleries/8343477/Wellcome-Image-Awards-2011.html" target="_blank">The Telegraph</a>]</p>These glowing layers reveal the complex structure of the retina--the photoreceptive part of the eye--in a mouse at one month old. Freya Mowat of University College London combined six different images to achieve this level of detail.These bacteria look cool, but don't be fooled: They're the periodontal microorganisms that cause plaque on your teeth. <em>Capnocytophaga</em> and <em>Aggregatibacter</em> bacteria are growing on a plate in this picture. They were taken from a patient with advanced gum disease.Spike Walker lit up this curled ruby-tail wasp with two flashes to make its iridescence shine for this image. The colors reveal the wasp's anatomy: Its head and thorax glimmer in blue while its abdomen glistens in ruby red.Stare deep into the eye of this three-day-old <a href="http://en.wikipedia.org/wiki/Zebrafish" target="_blank">zebrafish</a> and you'll see its components beginning to form. The lens appears in yellow, the cells that have begun to turn into retinal neurons are in purple, and the cells that have yet to differentiate appear in red.

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Related Content:
DISCOVER: The Alluring and Alien Sights of a Bee in Ultra Close-Up
DISCOVER: The Funky Fungi Freak Show
DISCOVER: Far Out: The Most Psychedelic Images in Science
80beats: Illustrations of HIV, Quasars & Fungi Win Science Visualization Challenge

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February 24th, 2011 Tags: art, bacteria, eyes, fish, insects, science images, teeth, wasps, Wellcome Collection
by Andrew Moseman in Living World, Physics & Math, Top Posts | No Comments » | RSS feed | Trackback >

How Sandfish Lizards Slither So Quickly Through the Sahara

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]

(more…)

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February 24th, 2011 Tags: Africa, lizards, locomotion, robots, Sahara, sand
by Andrew Moseman in Living World, Physics & Math | 1 Comment » | RSS feed | Trackback >

Scientists Create the World’s First Anti-Laser


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.

(more…)

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February 18th, 2011 Tags: anti-laser, lasers, light, photons
by Andrew Moseman in Physics & Math, Technology, Top Posts | 18 Comments » | RSS feed | Trackback >

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      80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.

      80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].



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