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Margaret Harris: February 2011 Archives

Eye-catching exhibits

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Science on a sphere

By Margaret Harris in Washington, DC

No trip to the AAAS meeting would be complete without a tour of the exhibit hall, which for the past two days has been buzzing with visitors to “Family Science Days”, a public outreach-oriented event running in parallel with the more technical seminars.

One of the most eye-catching exhibits was the National Oceanic and Atmospheric Administration’s Science on a Sphere, which pretty much does what it says on the tin. The Sphere is the brainchild of Alexander McDonald, director of NOAA’s Earth Systems Research Laboratory, and there are now over 250 datasets that can be displayed on it. In this photo, it’s illustrating the shock waves that spread around the globe after the Boxing Day tsunami of 2004, but I also saw depictions of ocean currents, aeroplane flight paths, global temperatures and the past week’s weather. According to exhibitor Jana Goldman, there’s even one in a science fiction museum in Seattle, Washington that displays the (hypothetical) features of a (fictional) alien planet – so it’s definitely a versatile beast!

Another exhibit that got a lot of traffic was the US Department of Energy’s set of bicycle-powered light bulbs, which is designed to teach kids (and maybe some adults) about the differences between voltage and current, and to demonstrate in a very physical way how much power it takes to light up an incandescent 50 W bulb compared with fluorescent and LED bulbs. The young gentleman in this photo, for example, was having real trouble getting the incandescent bulb to give off any light, but despite being a little too short for the pedals, he managed the LED bulb just fine.

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Bicycle-powered light bulbs

For the bigger kids, exhibitor Steve Eckstrand keeps a 12 V, 300 W hairdryer on hand. “They can usually get the 50 W bulb working just fine, and one girl did manage to pedal hard enough to get a faint glow out of the 100 W bulb,” he says. “But nobody can do more than get the hairdryer sort of gently warm.”

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By Margaret Harris

As a veteran of many stupendously boring – but mandatory – safety training sessions, I was initially tempted to give a wide berth to a booth in the AAAS exhibit hall on lab safety.

However, two things persuaded me to linger at this particular kiosk, which had been set up by the National Institute of Health (NIH) Division of Occupational Health and Safety. One was a statistic related to me by Kersten Haskell, a science communicator at the NIH. “We have a lot of students who come into NIH labs as interns in the summer, and what we found was that of all the injuries that were happening during that time, around 75% were to students,” she said. “So we figured we had to find a way to train them better.”

The NIH’s solution to this problem was to put essential elements of safety training into a video game. This brings me to my second reason for stopping: the row of monitors displaying scenes from the Safe Techniques Advance Research – Laboratory Interactive Training Environment (STAR-LITE). This visually appealing, easy-to-use game allows students (and visiting journalists) to guide avatars through typical lab-safety situations, solving problems and receiving points (or injuries) in the process – and I couldn’t resist giving it a quick test.

The game is clearly designed with health research in mind. In fact, it’s dedicated to the memory of a biology student, Beth Griffin, who died after contracting the rare macaque-borne B virus in a laboratory. However, I was pleasantly surprised to find that many of the hazards addressed in the game could apply equally well to physics. For example, my avatar spent a happy five minutes securing gas bottles and labelling hazardous chemicals (something I did many times while working in real-life physics labs) before I reluctantly turned the game back over to Haskell and her colleagues.

STAR-LITE is principally aimed at secondary-school students and new undergraduates, but if anyone wants to have a go, it’s free to download – and it’s a heck of an improvement over the grainy videos from the 1980s that made up the backbone of my own safety training.

The atomic detectives

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By Margaret Harris in Washington DC

One July day not so long ago, a shipment of scrap metal entered an EU seaport from somewhere outside the EU. No-one who watched the shipment being unloaded saw anything out of the ordinary. But when it went through the port’s radiation detector, alarm bells began to ring – and they rang again the next month with another shipment, and for a third time in October the same year. What was going on?

This is the story of “Find 33,” a case study from the emerging science of nuclear forensics that formed the basis of Klaus Mayer’s talk at an AAAS session on combating nuclear terrorism. Mayer, a scientist at the Institute for Transuranium Elements (ITU) in Karlsruhe, Germany, was called to investigate Find 33 after national authorities had isolated which particular bits of scrap were setting off the detectors.

The initial data were puzzling. The amount of enriched uranium in the four pieces of suspicious scrap ranged from a few percent to over 90% – values that suggested a mixture of commercial-grade and weapons- or research-reactor grade contamination. Could they have a common origin? Or were Mayer and his team dealing with multiple uncontrolled sources of radioactive and nuclear material?

After more detailed tests, a clearer picture began to emerge. A sample from the first piece of scrap – an extremely dirty funnel-shaped object – was found to contain 0.33% uranium by weight, of which the fraction of enriched uranium (U-235, the isotope used in both nuclear weapons and reactor fuel) was 9%. This was unusual: 9% is too high for a commercial reactor, which typically uses fuel that is <5% enriched, but too low for fast-breeder reactors (20%), submarine fuel (20-45%) or weapons (>90%). However, after grinding the sample into powder, Mayer and his team were able to show that it was actually a mixture of 3.6%-enriched and 20%-enriched particles. Radiochemical tests also showed that the uranium in it was old – it hadn’t been chemically purified since 1962.

ITU_Find33pic.jpgA piece of contaminated scrap from Find 33. (Courtesy: VROM-Inspectorate)

The other three scraps were analysed in a similar fashion, turning up a mixture of ages (June 1959, June 1972, October 1983) and enrichment fractions that ranged from a few percent for the second scrap to a sobering 89% for the fourth. This indicated that wherever these scraps had come from, it had to be someplace that had been producing a mixture of light-water reactor fuel, fast-breeder reactor fuel, submarine fuel and material for research reactors or weapons for at least 30 years, between the late 1950s and early 1980s.

And there were only two sites that fit the bill.

Sadly for this story’s narrative arc, Mayer declined to provide any further information on the two candidate facilities, citing an ongoing investigation. One thing, however, is certain: with 207 illicit trafficking incidents recorded in 2010 alone, the atomic detectives are keeping busy.

AAAS by the numbers

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By Margaret Harris

As a physicist, I’m a big fan of numbers, so here are a few outstanding ones I collected from today’s sessions at the AAAS meeting:

NASA’s Space Shuttle can carry up to 16,000 tonnes of cargo back to Earth from the International Space Station (ISS). After the shuttle is retired later this year, any cargo that needs to be shipped from the ISS will have to fit inside a Russian Soyuz capsule, which has a cargo capacity of 50 kg. (Source: NASA astronaut Sunita Williams)

Of the estimated 60 million tonnes of krill in the ocean around Antarctica, up to 5 million tonnes can be harvested each year without harming the long-term sustainability of the population. (Source: George Watters, US Antarctic and Marine Living Resources Program)

2.1% of the 2900 employees of NASA’s Goddard Space Flight Center have a disability – one of the highest percentages of any US government employer. (Source: Dan Krieger, program manager, NASA/Goddard)

Once it’s up and running in the early 2020s, the Square Kilometer Array radio telescope will produce 400 terabytes of compressed data every second. Without compression, it is estimated that the amount of data generated by SKA would exceed the current traffic of the entire World Wide Web. (Source: Bernie Fanaroff, project director, SKA South Africa)

And finally…

A 10 stone person would have to expel bodily gases at a rate of 17 million m/s in order to achieve lift-off by farting. (Source: Chris Smith of The Naked Scientists)

By Margaret Harris in Washington, DC

Greetings from Washington, DC, where the 2011 meeting of the American Association for the Advancement of Science is getting off to a gentle start this afternoon before the firehose of information switches on tomorrow.

Between today and Monday (17–21 February) there will be more scientific symposia, plenary talks, career workshops and poster sessions here in America’s capital city than you can shake a very large stick at. In fact, there’s so much going on that I’m not the only one from physicsworld.com attending this year: my colleague Michael Banks is navigating DC’s excellent Metro system as I type this, and between the two of us we’ll try to bring you as much of the conference’s physics news as possible.

One of the themes of this year’s conference is interdisciplinary science, and that was certainly on display at this afternoon’s press briefing on adaptive optics. Regular readers of Physics World will already know that adaptive optics is not just for astronomers anymore – we published a feature by Alan Greenaway on adaptive optics in cell biology just a few months ago, in August 2010 – but it was still surprising to find an astronomer (Norbert Hubin of the European Southern Observatory) sharing the stage with a biophysicist (Eric Betzig of the Howard Hughes Medical Institute) and an opthalmologist (Joseph Carroll, Medical College of Wisconsin).

Hubin, of course, is interested in adaptive optics on a grand scale – tools like laser guide stars, and systems of actuators that can make 100 adjustments to a telescope mirror every milisecond, producing images up to three times sharper than the Hubble Space Telescope despite Earth’s turbulent atmosphere.

Betzig, for his part, uses genetic engineering to label clumps of mouse neurons with a fluorescent marker. Once the mouse matures, these glowing clumps become his “guide star” when he images processes that take place up to 500 microns below the surface of a live mouse’s brain.

And Carroll is using adaptive optics to image the human retina on a cellular level, with the goal of diagnosing diseases like glaucoma and diabetic retinopathy at earlier stages, before they cause irreversible damage. “We hope to be able to tell people 10 years before they would have known otherwise that they have this disease, and then treat them,” he told me.

Both Carroll and Betzig emphasized that their adaptive-optics work is still in its early stages – “We are neophytes compared to astronomers,” Betzig admits – but there’s a clear sense of excitement about where this technology could go in the future, as more and more scientists pick up on these astronomy-inspired “tricks of the light” and adapt them for their own needs.