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What You Need to Know About Mt. Gox and the Bitcoin Software Flaw

Here's what a terrible week looks like in the world of Bitcoin: Two of the most trafficked Bitcoin exchanges, Mt. Gox and Bitstamp, temporarily halt trading and suspend bitcoin withdrawals in the midst of a distributed denial of service attack (DDoS). On exchanges that are still open for business, the value of the currency takes a brutal, sudden hit and then continues to tumble. Bitcoin users notice strange errors in their wallet balances after making routine transactions. Rumor spreads that the Bitcoin protocol is critically flawed. And where rumor is lacking, conspiracy theories abound.

All this, and it's barely Thursday.

Some of it is true. Some of it is half true. Some of it is completely false. Here is what's really going on.

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National Ignition Facility Achieves Record Energies

Big fusion milestones are rare things. But a team based at the National Ignition Facility (NIF) says they've reached one. For the first time, they've been able to get their deuterium-tritium fuel to fuse so that it produces more energy than was deposited into it.

The researchers are quick to note they've not achieved the long-awaited goal of ignition—a self-sustaining fusion reaction that produces more energy than what is sent into the experiment. Most of the 1.8 megajoules of energy in the facility's lasers is still lost in the effort to achieve the temperatures and pressures needed to get fusion started. This process involves hitting the inside of a cylindrical gold container with 192 lasers in order to produce X-rays. That radiation then heats and blasts away the outer layer of a spherical capsule suspended at the center of the cylinder. The reaction force sends the remainder of this target inwards, compressing some 170 micrograms of frozen deuterium-tritium fuel at the center.

Today only about 1 percent of the energy poured into the cylinder actually winds up in the fuel. Still, team leader Omar Hurricane told reporters in a press briefing on Monday that this latest milestone is "kind of a major turning point in a lot of our minds." The results are published this week in a paper in Nature(A similar announcement was made in August of last year, when some 8000 joules of energy were released in the form of neutrons. In this paper, the team reports yields as high as 17 000 joules.)

The team is also encouraged by evidence of what's called alpha particle heating—a process by which helium atoms created in fusion reactions deposit their energy into the fuel instead of escaping. This "bootstrapping" process—using fusion to create more fusion—is what will be needed to ultimately get the yield up to ignition levels.

NIF has been taking a more research-oriented approach to fusion since late 2012, when the facility wrapped up the National Ignition Campaign, aimed at achieving ignition in just two years. The laser shots fired during that campaign tended to have what's called a "low-foot"—the laser power began at low power and was then ramped up. This approach made target compression fairly easy, but it created instabilities and asymmetries that sap power out of the compression process. "Those early implosions tended to rip themselves apart," Hurricane told reporters on Monday.

He and his colleagues took what might be called a step back, experimenting with "high-foot" pulses. These laser shots start out at high power, which quickly raises the temperature of the capsule. This approach makes capsule shells harder to compress, but also increases the speed at which layers are blasted off the capsule, which helps stop instabilities from growing. "Those two effects act together to make it more stable," Hurricane said. 

The team is now exploring ways to increase the yield even further with adjustments to capsule design.

In terms of yield, NIF is still behind the magnetic confinement approach pursued by experiments such as the Joint European Torus (which currently holds the record), Steven Cowley, director of the UK's Culham Centre for Fusion Energy, told IEEE Spectrum in an email. But he adds both approaches are now finally, after 60 years, getting "close" to controlled fusion. "We must keep at it."

A Hearing Device With No Stigmatizing External Hardware

Cochlear implants are among the most successful hearing devices out there. They have been around for about 30 years and more than 220 000 people worldwide enjoy restored hearing because of them. But they require clunky hardware mounted onto the skull and behind the ear that limit their use in the shower and often stigmatize the people who wear them. But this week, a team of scientists will present a new, alternative design that eliminates all the external hardware of the traditional cochlear implant and allows it to be charged wirelessly with a smartphone. 

The key to the new design is an implantable low-power signal-processing chip developed by Anantha Chandrakasan and his colleagues at MIT in Cambridge, Mass. The team cleverly integrated its microchip with an implantable piezoelectric sensor, and has tested the system in a human cadaveric ear. They will present their paper this week at the International Solid-State Circuits Conference in San Francisco. (Chandrakasan is the same researcher who in 2012 demonstrated how to harvest energy from the middle ear.)

Chandrakasan's new device works like this: A piezoelectric sensor mounted at the umbo in the middle ear picks up sound. That signal, a measure of the sound-induced motion of the umbo, travels to the microchip implanted elsewhere in the ear, where it is conditioned, digitized and processed. The chip then converts the signal to electrical waveforms and pumps them to electrodes implanted in another part of the ear called the cochlea. The waveforms received by the electrodes stimulate auditory nerve fibers and make the sound audible to the user. The device can be charged wirelessly in just a couple of minutes using a mobile phone and special adapter.

The design would be a huge improvement over existing cochlear implants, which require the user to wear the external components—mainly for power—at all times.

Researchers elsewhere have been working on alternatives to today's cochlear implants as well. In 2012, Darrin Young at the University of Utah designed a MEMS-accelerometer-based middle ear microphone that also moves all the external components of the cochlear implant inside the body. But Young's sensor draws a few milliwatts of power—more than MIT's design. An implanted rechargeable battery will be required. Young says his team is working on improving the prototype. "We are expecting a further power reduction by at least a factor of 20. This will bring down the power below 100uW," he said.

Further work, particularly on the sensor component, is needed before MIT's chip is ready to be implanted in a human. The geometry of the sensor still needs to be optimized, as does the method of stabilization, says Konstantina Stankovic at Harvard Medical School, who collaborated on the project. "A tricky thing with the implantable sensors has been stable placement and avoidance of sensing bodily noise," she says.

Now on Google Earth: 150 Years of Global Temperature Data

The Climate Research Unit (CRU) of the University of East Anglia has made its worldwide historical record of over-land temperature data available as an overlay on Google Earth. (And non-KML, comma-delimited temperature data files, along with many other kinds of climate records, are available at The CRU Temperature database, version 4 (CRUTEM4) includes information from some 6000 weather stations, with some time series reaching back to 1850.

The big new data sets may leave some people cold. Others, though, look forward to poring over gigabytes of new information with the glee of Scrooge McDuck diving into a pile of gold doubloons.

The CRUTEM4 Google Earth data is provided in Keyhole Markup Language (KML is named after its developer, Keyhole, Inc., which was acquired by Google). The CRUTEM4 KML schema divides the Earth’s land surface into 780 grid boxes, each 5 degrees latitude by 5 degrees longitude. Users can click any box to see temperature information for that area: options include year-by-year variations (called “anomalies”) from historical means, tracing changes in annual and seasonal average temperature. By default, these consolidated data are “homogenized”—processed to emphasize variations above and below the mean, without noting what that mean temperature might be. The un-normalized temperature data are, however, available at a deeper level: users can drill down to see annual and seasonal temperature data for each individual weather station—like, for example, the station at Krasnaya Polyana, in the mountains near Sochi, Russia, where many Winter Olympics events are now underway.

CRUTEM’s curators, the University of East Anglia’s T.J. Osborn and P.D. Jones, describe CRUTEM and the Google Earth expansion in an Earth Systems Science Data paper. They go into detail on the mechanics and rationale of homogenization—sometimes extensive adjustments needed to compensate for missing data, suspect data, and systematic variations (e.g., changing the method of temperature measurement or moving the measuring station to a different altitude).

CRUTEM4 is the latest in a series of CRUTEM incarnations dating back to 1986. This release, offering increased transparency of the data, may be of particular interest because Osborn and Jones were among the climate researchers embroiled in controversy following the release of stolen CRU e-mails in 2009 and 2011. Widespread accusations, surfacing first among bloggers who resist the idea of climate change, charged climatologists at CRU and elsewhere with trying to derail the peer review process and stifle opposing views. Subsequent investigations by University of East Anglia, Pennsylvania State University, and the House of Commons, among others, largely exonerated the “pro-warming” researchers of wrongdoing, but the brouhaha did succeed in tarnishing reputations of climatologists whose work indicates global warming, and burnishing the rhetoric, if not the substance, of climate-change deniers.

Though there had been speculation that the e-mails had been stolen by a disaffected person inside the University of East Anglia, British police concluded in July 2012, that “the hack was the work of ‘sophisticated’ outsiders, not a whistleblower at the university,” according to The Guardian. Authorities nonetheless closed the case, because, they said, they did “not have a realistic prospect of identifying the offender or offenders and launching criminal proceedings within the time constraints imposed by law.” 

D-Wave's Quantum Computing Claim Disputed Again

The strongest scientific evidence for D-Wave's claim to have built commercial quantum computers just got weaker. A new paper finds that classical computing can explain the performance patterns of D-Wave's machines just as well as quantum computing can—a result that undermines crucial support for D-Wave's claim from a previous study.

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Bitcoiners Destroy Their iPhones After Apple Removes Wallet From App Store

On Wednesday, Apple removed the Blockchain wallet app, the only remaining app that could be used to make Bitcoin payments on the iOS platform, from its App Store. And Bitcoiners are pissed off. How pissed off? One particular Apple customer was so angry that he blasted his iPhone to smithereens with a rifle. Luckily for us, he filmed himself doing it.

He did, however, have more to gain than a rush of sublime catharsis and 15 minutes of YouTube fame. Ryan, as he identifies himself in the video, shot up his phone in a spirit of protest, but only after a Reddit user besought enraged Bitcoiners to publicly destroy their iOS devices with the promise that he would send them new, Nexus 5 smartphones in return. The user, "round-peg," promised one replacement phone for each 100 "upvotes" he got on the Reddit post, but limited it to six phones after a deluge of attention.

It seems that this was the last straw for many iPhone-toting Bitcoin users. The Blockchain app was only the most recent Bitcoin app to get pitched from the Apple marketplace. Last November, it shut down another app which allowed users to interface with Coinbase accounts (Coinbase functions both as a Bitcoin wallet and a Bitcoin exchange.) In December, it booted a comparable app designed by CoinJar (though it's still available to Australian customers). And last month, Apple forced Gliph to remove Bitcoin transaction features from its secure messaging app. All of these apps are still available in the Google Play Store for use on Android phones, such as the Nexus 5 (except CoinJar, which says it's still working on it).

Apple has not made a public statement about why it's coming down so hard on Bitcoin. And according to the San Francisco Chronicle, company representatives declined to comment about this latest decision. But the snubbed app designers are coming up with their own theories. 

In a blog post yesterday, Blockchain went on the offensive, writing:

These actions by Apple once again demonstrate the anti-competitive and capricious nature of the App Store policies that are clearly focused on preserving Apple's monopoly on payments rather than based on any consideration of the needs and desires of their users.

Tim Cook, CEO of Apple, dropped some less than subtle hints to Time Magazine last week, suggesting that the company would have some kind of mobile payments platform to offer with the next iphone. It's not difficult to see how a global, frictionless, digital currency might get in the way of those plans. 

But it's also important to keep in mind that Bitcoin is going through some serious growing pains right now. These are Bitcoin's awkward, teen years, when it just keeps rolling with the wrong kids and getting into trouble. In the last six months, the biggest news stories about Bitcoin have involved the arrests of an alleged drug kingpin and the twenty-something millionaire that may or may not have been laundering money for his customers. And it's still anyone's guess as to how governments will choose to regulate Bitcoin, or even how they will define it. So, it's not inconceivable that Apple, a notoriously skittish company, might shy away from Bitcoin for the moment.

This seemed to be the impression that CoinJar got from its dealings with Apple. After having its app pulled, it explained to its users:

Before you start DDOSing and trolling, Apple have done nothing wrong in this situation, they are just managing their own legal liability. We have had amicable discussions with them and hope they will support us in the future, when they have a more clear view of Bitcoin's place in their regulatory landscape.

Regardless of how angry people are about this decision, the reality is that Bitcoin is still so small that it can't yet muster an impressive public outcry. Of course, there's already a petition started, but I'm guessing that Apple has made up its mind on this one, and it's not likely to change course, even if people start shooting their phones with canons tomorrow. I say, Bitcoiners, do what you do best, and opt out!  

Lockheed Martin Shows Off High-Power Fiber Laser Weapon

The US military dreams of a small but powerful laser weapon that can zap enemy rockets and drones from a safe distance. But weapons that have been demonstrated so far have been too big and heavy to fit on-board humvees and fighter jets. They’re also notoriously difficult to cool.

So key players in the defense industry have turned to fiber lasers to make the military's dream a reality.

Lockheed Martin said last week that it has demonstrated a 30kW fiber laser. In May 2013, Lockheed was able to shoot down rockets with a portable 10kW fiber laser from about 1.5 km. The company claims in a press release that this latest achievement is “the highest power ever documented while retaining beam quality and electrical efficiency” and that the fiber laser consumes half the power of more conventional solid-state laser.

MBDA Systems, Raytheon, and Northrop Grumman have all reported their own high-power fiber laser weapon feats in the past couple years. In October 2012, MBDA Systems’ German subsidiary used its 40kW system to shoot down airborne artillery from a distance of 2  km. The 40kW system was built with four 10kW sources provided by industrial fiber laser maker IPG Photonics. Northrop Grumman is also busy developing high-power fiber lasers through various military contracts, including the Army’s Robust Electric Laser Initiative.

Fiber lasers use a special type of optical fiber as the light-emitting material, as opposed to the neodymium-doped crystals used in conventional solid-state lasers. Because the fiber can be coiled, developers can pack more power into a compact system. They can  be up to two times more efficient than traditional solid-state lasers, and the larger surface-to-volume ratio of the fibers makes them much easier to cool.

They do have a power limitation, though. Single-fiber lasers can’t achieve high power and beam quality. So most high-power systems, including Lockheed Martin's, combine beams from multiple fiber laser beam modules into a single high-quality beam. Some believe that the military's 100-kW benchmark power output for a laser weapon could be challenging to reach with fiber lasers.

That benchmark came about from an Army project from over a decade ago, which established that destroying a moving target from a kilometer or two away requires 100kW, mainly to overcome the spreading of the laser beam. But lasers have come a long way since, and as IEEE Spectrum outlines in the article "Ray Guns Get Real", some experts question the necessity of a 100-kW laser system. The recent demonstrations mentioned above certainly show that lasers delivering tens of kilowatts could be of use.

The real test for fiber lasers could come later this year, when the US Navy installs its laser weapon system on the USS Ponce transport ship, two years ahead of schedule. The Navy showed in 2010 that its laser weapon system, developed by Raytheon, could shoot down unmanned aerial vehicles.

Photo: U.S. Navy

Milestone Tests Help Refurbish Dwindling U.S. Nuclear Arsenal

Treat the test subject very, very carefully. It’s a thermonuclear bomb.

The B61 is an American tactical gravity device (a relatively low-energy bomb dropped from aircraft rather than carried on a missile) with a variable, 0.3-to-340-kiloton yield. It was designed in the early 1960s; the U.S. made some 3 100 B61s, in a number of different configurations, for deployment at home and in Europe.

Today (according to nuclear-weapons watchdogs at The Bulletin of the Atomic Scientists) about 200 B61s remain in service in the U.S. and 180 are deployed with NATO allies in Europe. While the U.S. military continues to reduce the number of H-bombs, they're also trying keep the few that remain in good working order until they can be scrapped. Thus, the B61, along with three types of nuclear warheads for submarine-launched and other missiles, is the object of a $US 11 billion Life Extension Program (LEP) designed to keep them operational into the 2030s.

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Internet Giants Disclose FISA Surveillance Requests For Customer Data

Technology giants such as Google, Microsoft and Yahoo have started disclosing U.S. government requests for customer information under a new agreement reached last month. But the first such reports on the controversial Foreign Intelligence Surveillance Act (FISA) orders remain limited in how much detail they reveal about the surveillance activities of the U.S. National Security Agency.

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Amputee Successfully Feels Prosthetic Grip Strength Via Arm Electrodes

For decades, amputees have been able to open and close prosthetic hands by twitching muscles and activating a superficial electromyogram (sEMG), but they had no way of feeling what the prosthetic was encountering and little control over the strength of their grasping grip. It was a clunky, incomplete solution.

But recently, an amputee who allowed European researchers to plug electrodes into a bundle of his wrist nerves was able to control the strength of a prosthetic hand's grip and to distinguish the shapes and stiffness of three kinds of objects. The 30-day trial marks a success for one of several new experimental ways of giving amputees a better sense of touch and control over their prosthetics. A different group has conveyed sensations of temperature and vibrations by moving arm nerves into intact muscles of the chest, which act as biological amplifiers of the nerves' tiny signals. Another team tapped into nerves in the lower spine of cats to control their limbs. The Defense Advanced Research Projects Agency, is also seeking to improve sensation and control of its advanced prosthetics.

In the latest trial, appearing in Science Translational Medicine today, biomedical engineer Silvestro Micera of the Swiss Federal Institute of Technology in Lausanne (EPFL) and a large team surgically attached electrodes from a robotic hand to a 36-year-old volunteer's median and ulnar nerves. Those nerves carry sensations that correspond with the volunteer's index finger and thumb, and with his pinky finger and the edge of his hand, respectively. The volunteer controlled the prosthetic with small muscle movements detected by sEMG, a method that dates to the 1970s and measures electrical signals through the skin—unlike the electrodes attached to his nerves, sEMG is not invasive.

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