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Laser Bug Zapper Inches To Market

If it’s over-the-top crazy to swat a fly with a sledgehammer, what are we to say of vaporizing one with a laser?

How about: good riddance. We need new weapons for the war on bugs, particularly disease-bearing mosquitoes, which are quick to evolve resistance to poisons and are hardly fazed by traps that lure them to their deaths. That’s because there are just too many of the little bloodsuckers out there, particularly in the malarial regions of Africa. 

After years in the blue-sky area of speculative inquiry, the laser bug zapper took its first solid step toward commercialization last week, when Intellectual Ventures, the patent-holding giant, announced that it had licensed the manufacturing of the system to Lighting Science Group of Melbourne, Florida, a maker of LEDs.

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A Brain-Computer Interface That Lasts for Weeks

Brain signals can be read using soft, flexible, wearable electrodes that stick onto and near the ear like a temporary tattoo and can stay on for more than two weeks even during highly demanding activities such as exercise and swimming, researchers say.

The invention could be used for a persistent brain-computer interface (BCI) to help people operate prosthetics, computers, and other machines using only their minds, scientists add.

For more than 80 years, scientists have analyzed human brain activity non-invasively by recording electroencephalograms (EEGs). Conventionally, this involves electrodes stuck onto the head with conductive gel. The electrodes typically cannot stay mounted to the skin for more than a few days, which limits widespread use of EEGs for applications such as BCIs.

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Now materials scientist John Rogers at the University of Illinois at Urbana-Champaign and his colleagues have developed a wearable device that can help record EEGs uninterrupted for more than 14 days. Moreover, their invention survived despite showering, bathing, and sleeping. And it did so without irritating the skin. The two weeks might be "a rough upper limit, defined by the timescale for natural exfoliation of skin cells," Rogers says. 

The device consists of a soft, foldable collection of gold electrodes only 300 nanometers thick and 30 micrometers wide mounted on a soft plastic film. This assemblage stays stuck to the body using electric forces known as van der Waals interactions—the same forces that help geckoes cling cling to walls.

The electrodes are flexible enough to mold onto the ear and the mastoid process behind the ear. The researchers mounted the device onto three volunteers using tweezers. Spray-on bandage was used once twice a day to help the electrodes survive normal daily activities.

The electrodes on the mastoid process recorded brain activity while those on the ear were used as a ground wire. The electrodes were connected to a stretchable wire that could plug into monitoring devices. "Most of the experiments used devices mounted on just one side, but dual sides is certainly possible," Rogers says.

The device helped record brain signals well enough for the volunteers to operate a text-speller by thought, albeit at a slow rate of 2.3 to 2.5 letters per minute.

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According to Rogers, this research: 

...could enable a persistent BCI that one could imagine might help disabled people, for whom mind control is an attractive option for operating prosthetics… It could also be useful for monitoring cognitive states—for instance, to see if people are paying attention while they're driving a truck, flying an airplane, or operating complex machinery. It could also help monitor patterns of sleep to better understand sleep disorders such as sleep apnea, or for monitoring brain function during learning.

The scientists hope to improve the speed at which people can use this device to communicate mentally, which could expand its use into commercial wearable electronics. They also plan to explore devices that can operate wirelessly, Rogers says. The researchers detailed their findings online March 16 in the journal Proceedings of the National Academy of Sciences.

ESA Rescues Errant Galileo Navigation Satellites

After long journeys two satellites that were parked in wrong orbits have reached a "corrected" orbit, allowing them to become part of Europe’s GPS system. When launched in August of last year, a design flaw in the fourth stage of the Soyuz launcher caused the injection of both satellites into orbits that brought them through the Van Allen Belts but also made them unusable as navigation satellites.

At first, things looked grim. The two satellites, the fifth and sixth of a series of 30 satellites, had hydrazine fuel for their thrusters, but the amount was only sufficient for small orbit corrections, not for mayor orbit changes. However, in November ESA engineers used the fifth satellite’s thrusters, to nudge its orbit’s lowest point 3500 km farther from Earth—making the orbit more circular. Testing showed that its electronics were not damaged by Van Allen Belt radiation, and in December it performed, in combination with the other Galileo satellites, its first navigation fix.

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Instead of Dropping Bombs, Can Drones Locate Unexploded Ones?

In much of the world, an American drone flying overhead means danger: Predator drones and the like can unleash fury out of the deep blue sky. But drones can also help war-torn countries recover, argued Ryan Baker, CEO of drone maker Arch Aerial, at a SXSW Interactive talk yesterday. His company hopes to use its drones to identify locations that are likely to be riddled with unexploded bombs from past wars. 

Baker wants to start with Laos, which bears the terrible distinction of being the most heavily bombed nation ever: During the height of the Vietnam War, the country was pounded with about 2 million tons of ordnance. And Laotians today are still suffering the effects of that bombardment, as unexploded shells and landmines still litter the landscape. The biggest threat comes from the cluster bombs dropped during the Vietnam War, which scattered small explosives about the size of tennis balls. 

In Laos, “there have been some 12,000 accidents related to UXO [unexploded ordnance] since 1973,” said Baker. Most deaths and injuries occur when people try to remove unexploded bombs, he said, or when local farmers till their fields.

Baker said his company’s octocopter will carry a laser imaging system known as LIDAR (often used in self-driving cars) to survey terrain and identify locations where unexploded ordance will likely be found. LIDAR is useful because it can see through vegetation and create precision maps of the ground. By flying drones above Laos’s forests and fields, surveyors can look for topographical features signifying places that might have been targeted by bombing campaigns—such as bunkers and trenches, Baker explained. Arch Aerial plans to do some test runs this year in cooperation with one of the humanitarian groups working on unexploded ordance in Laos. 

This initiative is only possible because of rapid advances in LIDAR technology, Baker said. “A few years ago, a LIDAR system was the size of this table,” he said, “and had to be fitted into a gutted airplane.” And conducting a survey by plane requires plenty of money and compliance with flight regulations. Now, with a small and cheap LIDAR system aboard a drone, a surveyor could create an aerial map with “risk profiles” of the landscape before setting foot on the ground. 

Surveyors will still have to deal with public perception and the stigma surrounding drones, Baker noted, since Americans operating strange equipment are sometimes viewed with suspicion. But there’s an easy way to solve that problem, he said: Just hand the controls to a local. 

Your Body Is a Race Car. McLaren Wants to Optimize Its Performance

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It’s probably not good for the soul to think of life as a race to be won. But if you do accept that metaphor, you’d likely be happy to have McLaren managing your pit stops as you make your way along the course.

The engineering company is famous for building Formula One race cars featuring computerized engine control systems and dozens of sensors that transmit data to remote analytics teams. Over the last few years, McLaren first began applying lessons learned from managing race cars to managing elite athletes, and now it’s bringing its tools to health and medicine. 

Today at SXSW Interactive, Geoff McGrath described the origin and evolution of McLaren Applied Technologies, the business unit he founded within the company. McGrath also articulated three conditions that must be met in order to turn our bodies into high performance machines, with instruments and analytics helping us operate at our peak capacity. 

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Disney Research System Predicts Soccer Goals

Last weeked, Brazilian superstar, Kaká, scored in the final minute of his Major League Soccer debut for Orlando City Soccer Club. It was his fifth shot at goal, the second on target. Carlos Rivas, Orlando’s Colombian striker, also had five shots, but didn’t score. The match, against New York City FC, ended 1-1.

Soccer coaches often complain that their teams don’t take all the chances to score that they get. But, according to a group of Disney Research scientists, more chances don’t necessarily mean more goals. Germany beat Brazil 7-1 in the World Cup semi-final, last July, but Brazil had more shots on goal.

The Disney Research team released their paper, “Quality vs Quantity: Improved Shot Prediction in Soccer using Strategic Features from Spatiotemporal Data” at the 9th Annual MIT Sloan Sports Analytics Conference in Boston, on February 27th

They used player tracking data from sports analytics company Prozone looking at a season’s worth of shots on goal from an anonymous professional league. The data ccovered a ten-second window of play before each of the 9732 shots were taken.

During a soccer match, players are moving all the time. The role they play at any given moment will depend on the context of the match as it unfolds as much as their preassigned duties.  “We needed to align the tracking data so it told us which role a player is taking up, in each frame, rather than just their starting position,” says Patrick Lucey, who led the research team.

To work out the probability of different types of chances turning into goals, Lucey’s team used role representation software to analyse what players were doing, where and with who. “This enabled us to capture the nuances in general play, counter-attack, work out what role a player is performing during the 10 second segment being analyzed,” Lucey adds.

They also clustered each play into a specific match-contexts. This revealed that not all chances are created equal. The highest percentage of goals, they discovered, resulted from counter attacks—14.87 percent. Next came set pieces from a cross from a free-kick (10.05 percent), corners (8.97 percent) open play (8.26 percent) and finally free-kicks themselves (4.82 percent)

Nonetheless, two of Germany’s goals against Brazil in the World Cup came on the counter attack, one from a corner, and four from open play. Kaka’s debut goal was a deflected free kick. Analytics still can’t account for everything in the beautiful game.

Carbon Buckyballs Have a New Silicon Rival

Three years ago researchers created a 2-D silicon analogue to graphene, whereby silicon atoms form a similar honeycomb monolayer of atoms, a material that could combine the extraordinary properties of graphene with silicon’s semiconducting abilities. Researchers quickly moved to try to replace the carbon atoms of buckyballs with silicon atoms as well, but ran into difficulties because silicon’s chemical behavior is very different from that of carbon.

Now researchers have reported in Angewandte Chemie, International Editionthe discovery of a 3-D silicon analogue to carbon buckyballs. It contains a core of 20 silicon atoms stabilized by chlorine atoms (the researchers are therefore suggesting the term “fullerane” instead of “fullerene” for their compound.) The discovery was serendipitous, says Matthias Wagner, who with Max Holthausen, led the research at the Goethe University in Frankfurt, Germany. “One of my Ph.D. students, Jan Tillmann, discovered a small amount of crystals produced in a reaction involving hexachlorodisilane (Si2Cl6). He X-rayed them and found that they contained cages made up of 20 silicon atoms. It took him a year to optimize the reaction and now he gets a yield of about 30 percent,” says Wagner.

While carbon atoms happily link to one, two, three, or four other atoms, silicon atoms prefer to form bonds with four other atoms, which precludes a buckyball consisting of only silicon.  Consequently, the compound Tillmann discovered had a more complex structure. It contains a buckyball structure in the shape of a dodecahedron formed by 20 silicon atoms, with a chloride ion sitting at its center. Forming an exoskeleton of sorts around the silicon dodecahedron, are 12 silyl groups of atoms consisting of one silicon atom linked to three chlorine atoms (SiCl3). Another eight individual chlorine atoms are bound to the remaining vertices.

The 12 silyl groups make the silicon fullarene vulnerable to moisture. On the other hand, their chlorine atoms can easily be substituted by hydrogen atoms, explains Wagner: “This tells us that we can use the SiCl3 groups as functionalization sites” he adds. And this is where the silicon buckyballs could have a clear advantage over their carbon relatives, which are not very amenable to linking up with each other.

“What we are dreaming about is that we can use these SiCl3 substituents as anchor groups to interlink these fullerenes to form two or three dimensional networks—this is our long-term goal,” says Wagner.

Will this allow the introduction of new strategies for the further miniaturization of nanoscale silicon circuits? Finding out will be the focus of much of their future work. One project will be to determine the electrical and optical properties of these fullerenes. “We have just prepared the building blocks, and we hope for something like semiconductive properties. Compounds like this did not exist up to now, and now we have to see what we can do with them,” says Wagner.

Magnetosphere Satellites Launch

Update, 13 March: NASA’s Magnetospheric Multiscale mission had a picture-perfect launch from Cape Canaveral Air Force Base in Florida at 10:44 p.m. ET following a smooth countdown. All four spacecraft that are part of the mission "appear healthy following separation," the agency says.

To solve a mystery concerning powerful geomagnetic storms that can threaten Earth's satellites and power grids, NASA is launching a quartet of spacecraft into orbit on 12 Marchfor a two-year mission to analyze magnetic fields around the Earth.

A geomagnetic storm in March 1989 blacked out the entire Canadian province of Quebec, leaving millions of customers in the dark and damaging transformers as far as New Jersey, and ones 10 times worse are possible, such as the 1859 solar superstorm.

Every step leading to such intense bursts of space weather are ultimately driven by a mysterious phenomenon known as magnetic reconnection, which occurs in clouds of electrically charged gas known as plasmas. Magnetic fields are entrapped inside plasmas, and magnetic field lines can break and reconnect with each other within these clouds, explosively converting magnetic energy to heat and kinetic energy.

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Creating Lasers in the Sky

Collaborators working at labs in Russia, Austria, and the United States have succeeded in pumping more than 200 gigawatts of power into a 0.1-millimeter-wide filament formed in the ambient air by a laser. In a paper published in the 17 February issue of Scientific Reports, they describe how they created laser pulses in the mid-infrared part of the spectrum. By making them 100 femtoseconds (10-13 s) long, they could pack sufficient energy in these pulses to carve out a filament in the air several meters long. The researchers claim to have achieved a world record; but, at the same time, they say that they have hit up against a limit in the amount of power that can be transmitted via the filament because of the presence of CO2 in the atmosphere.

When lasers first appeared during the 1960s, expectations were high that laser guns would eventually replace rifles. However laser guns were soon relegated to the world of science fiction because even needle-thin rays produced by lasers quickly lose their punch because the photons spread out. “If you have a freely propagating laser beam, it will diffract,” says Alexey Zheltikov, a physicist who holds research positions at both Moscow State University and Texas A&M University. “This is a force of nature and there is nothing you can do as long as you are working in linear optics,” says Zheltikov, the scientist who led the research team.

By increasing the intensity of the laser pulses, nonlinear effects become dominant, Zheltikov explains. Because the beam, at high intensities, modifies the refractive index of air, and because the intensity of the beam is higher in the middle than at the edges, it creates a narrow tube like path with a higher refractive index in the middle, bending the light inwards.

But if it weren't for another nonlinear effect, there would be no filamentation.

This other effect occurs at even higher intensities, when the beam ionizes the air in its path. The electron density is the highest at the center of the beam. It is there that the beam lowers the refraction index and forms a negative lens, or plasma lens. The laser pulses focus and defocus simultaneously, maintaining the stability of the filament. “Filamentation is the balance between two nonlinear phenomena, self-focusing and self-defocusing due to the plasma lens,” says Zheltikov.

To achieve self-focusing, the pulses must carry a minimum amount of power; but too much power results in too much ionization, which disrupts the delicate balance struck by the plasma lens. This excess ionization is more likely to occur with pulses of shorter wavelengths, where photons have more energy and more ionizing power. The researchers found that the amount of power that can be transmitted through a filament created with 1-micrometer pulses is much lower than the power that can be transmitted with 4-µm (mid-infrared) pulses. In fact, the power that can be transmitted through a filament is proportional to the square of the wavelength, so 4-µm pulses can transmit 16 times as much power as 1-µm pulses.

Naturally, Zheltikov and his colleagues wanted the most powerful pulses possible. But pulses with wavelengths over 4 µm were quickly ruled out because CO2 in the atmosphere starts blocking the light. Still, at 4 µm, they could go for laser pulses packing more than 200 GW of power—16 times the power that achieved filamentation with a previous experiment by the group with a 1 µm laser.

However, suitable lasers that could produce 200 GW pulses were simply not available. The researchers solved this problem by starting out with a powerful 1-micrometer laser then downconverting the wavelength and amplifying the pulses via several stages of optical parametrical amplification. They ultimately obtained the required 100-femtosecond pulses of over 200 GW of power. “This is how we were able to achieve an unprecedented peak power in the mid infrared,” says Zheltikov. Unfortunately, because light absorption by CO2 rules out higher-power pulses, this the “ultimate experiment in the atmosphere,” Zheltikov adds.

Notwithstanding this limitation, there still is room for interesting applications such as remote sensing. It should be possible to focus the laser pulses in such a way that the filamentation occurs several hundreds of meters up in the atmosphere. There, analysis of the light emitted by the filament would allow specific molecules, such as air pollutants, to be identified.

And there is the "laser in the sky." In experiments with high-pressure gases, the researchers observed lasing of light within the filament, and the return of the amplified light to the laser. Created in the atmosphere, this backward signal would, for example, enhance remote sensing capabilities, or even the creation of artificial “guide stars” used for the adaptive optics of astronomical telescopes. “I have given a talk about this at a meeting with astronomers, and they are interested,” says Zheltikov.


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