Author Archives: Charles Day

Using magnetic fields to detect brain damage

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MIT Technology Review: A new and cheap helmet-shaped device can detect the accumulation of fluids that accompanies certain forms of brain damage. Designed by Cesar Gonzalez of Mexico’s National Polytechnic Institute and his colleagues, the helmet works by inducing a magnetic field in a patient’s brain with a set of coils. Another set of coils measures changes in the magnetic field’s phase that depend on the amount of fluid present. Although the helmet can’t locate where fluid levels are anomalously high, it’s cheap enough and compact enough to identify patients for follow-up tests. A pilot study succeeded in identifying cases of brain edema and hematoma.

Massive asteroid will fly by Earth on 31 May

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Los Angeles Times: Asteroid 1998 QE2 measures 2.7 km across and is covered in a black, sooty material. It’s also on course to come within 5.8 million km of Earth on 31 May, just before 5 pm EDT. The close approach will give astronomers the chance to study the asteroid’s shape, rotation, and surface. Features as small as 3.5 meters should be resolvable by radio telescopes. Backyard astronomers, however, won’t be able to see it.

Experiment measures excess of cosmic positrons

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Physics: The first results from the Alpha Magnetic Spectrometer (AMS) experiment, a project 18 years in the making and orbiting aboard the International Space Station since May 2011, were announced yesterday. AMS counts the arrival of positrons, the electron’s antiparticle, as a function of their energy. Years ago the PAMELA and Fermi missions established that high-energy positrons were more copious than well-understood cosmic-ray theory predicted; AMS confirmed those results with much greater precision and extended the measured positron energy range. An exciting possibility is that the extra positrons result from interactions of the mysterious dark matter that makes 5/6 of the universe’s material stuff, but astrophysical objects such as pulsars also generate positrons. AMS has been collecting data for two years and should be collecting for another decade or two. The instrument will further extend the energy range of the positron spectrum and may provide the data that convincingly determine the source of the positron excess.

Veteran scholar of education attacks test-score-based teacher evaluations

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New York Review of Books: For decades, New York University education professor Diane Ravitch has written about, spoken about, and served US education, including as an official in the administration of President George H. W. Bush. In her NYRB commentary she bluntly condemns teacher-performance metrics based on scores from standardized tests. Framing her national argument in terms of current education politics in New York, she asserts that such tests “are not yardsticks” or “scientific instruments,” but instead “are social constructions, and quite apart from how contingent their results are on the social and economic background of the students being tested, they are also subject to human error, sampling error, random error, and other errors.” She also condemns common analogies: “It is true that the cleanliness of restaurants can be given a letter grade,” that “agribusiness can be measured by crop yields,” and that “corporations can be measured by their profits,” she writes. But “to apply a letter grade or a numerical ranking to a professional is to radically misunderstand the complex set of qualities that make someone good at what they do. It is an effort by economists and statisticians to quantify activities that are at heart matters of judgment, not productivity.”

Organized crime cripples renewable-energy efforts in Italy

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Washington Post: A front-page article reports on “the latest wave of sting operations revealing years of deep infiltration into the renewable energy sector by Italy’s rapidly modernizing crime families.” Those operations raise “fresh questions about the use of government subsidies to fuel a shift toward cleaner energies.” Critics are “claiming huge state incentives created excessive profits for companies and a market bubble ripe for fraud.” The Post notes that the discoveries “follow so-called ‘eco-corruption’ cases in Spain, where a number of companies stand accused of illegally tapping state aid.” Much of the problem centers in Sicily, which not only has “infamous crime families” but plentiful sunshine and wind. Authorities have seized about one-third of Sicily’s 30 wind farms plus several solar power plants, have frozen more than $2 billion in assets, and have made a dozen arrests. The story probably owes its front-page placement to what it never mentions: its obvious potential as a cautionary tale for political exploitation in the US, where some critics protest government support of renewable-energy business ventures, and where allegations of fraud followed the failure of the government-backed renewable-energy venture Solyndra.

Scientists are ignored despite threats to the planet, says physicist Krauss

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New York Times: Under the headline “Deafness at doomsday,” theoretical physicist and science popularizer Lawrence M. Krauss argues in an op-ed that until “science and data become central to informing our public policies, our civilization will be hamstrung in confronting the gravest threats to its survival.” He sees “great peril” in a diminishment of scientists’ influence, which he suspects stems from the loss of the post–World War II direct responsibility of scientists for nuclear weaponry. In any case, he asserts, scientists’ voices are unheard concerning climate, nuclear proliferation, and “the potential creation of new and deadly pathogens.” Citing Iran, India, and Pakistan, he calls proliferation “as alarming as ever.” He observes that the Comprehensive Nuclear-Test-Ban Treaty is not ratified by the US despite advice from the National Academy of Sciences, and that another academy study, “on flaws in America’s costly ballistic missile defense program, has had little impact.” In Washington, Krauss writes, “ideological biases have become so ingrained . . .  that scientific realities are subordinated to political intransigence.”

Egypt’s new constitution draws mixed reactions concerning science

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SciDevNet: Egypt’s new constitution calls for support of science, but some science supporters worry that it fails to link science to development, that it depicts science as a luxury, and that it calls unwisely for science’s “Arabization.” The constitution guarantees “freedom of scientific and literary research,” requires that the “autonomy of universities, scientific and linguistic academies, and research centers . . . be safeguarded,” and mandates that the state “provide them with a sufficient percentage of the national revenue.” However, it also requires the state to “foster the Arabization of education, science and knowledge.” Ehab Abdul Rahman, director of the Yousef Jameel Science and Technology Research Center at the American University in Cairo, warns that Arabization “would isolate Egypt from global scientific progress.” Cairo University medical professor Omaima Kamel is a member of both the Constituent Assembly and the Islamist Muslim Brotherhood’s Freedom and Justice Party. She approves of translating research and scientific knowledge into Arabic, but opposed the explicit Arabization provision.

How European forecasters predicted Sandy’s path before their US counterparts

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Ars Technica: A week before Superstorm Sandy struck the coast of New Jersey, the European Centre for Medium-Range Weather Forecasts (ECMWF) predicted the storm would indeed make landfall, whereas the US National Weather Service (NWS) had the storm veering off into the Atlantic Ocean. The NWS model fell into line with the ECMWF model three days later and enabled the NWS to issue timely, life-saving warnings. Still, the apparent shortcoming of the NWS model has highlighted a gap in investment between the US and Europe, writes Scott Johnson for Ars Technica. Not only does the ECMWF model run on a faster supercomputer than the NWS model does, but the European model has finer spatial and temporal resolution. Both advantages enhance accuracy. Comparisons aside, the ECMWF and NWS models rely on data gathered by Earth-observing satellites. If that fleet is not replenished, the accuracy of weather prediction will suffer. Indeed, after Sandy had dissipated, the ECMWF reran its model with data available five days before the storm’s landfall but omitted data from NASA’s polar-orbiting satellites. Without those data, the ECMWF model failed to predict Sandy’s destructive path.

New material is one-sixth as heavy as air

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Euronews: The record for the world’s lightest material has been claimed by a new material called aerographite. Fabricated by Matthias Mecklenburg of Hamburg University of Technology and his colleagues, aerographite consists of interwoven threads of carbon nanotubes, each about 15 nm in diameter. With a density of just 0.2 mg/cm2, the mesh-like material is so light that the slightest movement in the lab stirs up currents that can blow it away. Mecklenberg envisions using aerographite for applications, such as filtration and catalysis, for which both lightness and a large surface area are needed.

New form of photon-based quantum computation realized

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Science: Four groups have recently demonstrated the feasibility of a new form of quantum computation known as photonic boson sampling. The technique entails sending photons through a network of criss-crossing channels and observing which of several exits they emerge from. Thanks to the photons’ quantum mechanical interactions and to the network’s topology, the number of photons recorded at each exit correspond, together, to a matrix function known as the permanent. By using three input channels, the four groups determined the permanents of 3 × 3 matrices. That’s hardly a feat of computational power, but if the technique could be scaled up to 25 × 25 and bigger matrices, it could be used to determine permanents faster than a classical computer could. The four groups that demonstrated photonic boson sampling are those of Andrew White at the University of Queensland in Brisbane, Australia, Ian Walmsley of the University of Oxford in the UK, Philip Walther of the University of Vienna, Austria, and Roberto Osellame of the Polytechnic University of Milan, Italy.