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Updated: 6 days 14 hours ago

Reversed diffraction in bio-inspired photonic materials

13 October 2014
Hierarchical structures in a butterfly's wing and in a lab produce novel optical effects.

<em>Wall Street Journal</em> op-ed disputes physics Nobel achievement’s provenance

13 October 2014
The prize committee is said to have “overlooked fundamental discoveries made at RCA four decades ago.”

Black hole analogue produces sonic Hawking radiation

13 October 2014

New Scientist: In 2009, Jeff Steinhauer of the Technion–Israel Institute of Technology in Haifa and his colleagues made a model of a black hole using a Bose–Einstein condensate (BEC) and a pair of lasers. The first laser held the BEC in a narrow tube, and the second accelerated a portion of the material so that it flowed faster than the speed of sound. That created two horizons, one where the material transitioned from still to supersonic and another inside that one where the material slowed again. Now Steinhauer’s group says that they have seen an analogue to Hawking radiation—the release of particles due to quantum effects near a black hole’s event horizon. For their sonic black hole, the radiation is in the form of phonons, “particles” of sound, which are created in pairs, with one phonon escaping and the other being trapped between the two horizons. It is the trapped phonons that the researchers saw, because as the particles bounce between the horizons, they create more phonon pairs, which amplifies the signal to the point that it could be detected.

Prehistoric icebergs may have drifted as far south as Florida

13 October 2014

Nature: Massive icebergs carried by prehistoric floods may have traveled down the North American coast as far south as Florida, according to a recent study published in Nature Geoscience. Some 20 000 years ago, as the North American ice sheet began to melt, giant icebergs up to 300 m thick appear to have broken off and been carried by the massive flooding not only into the northern Atlantic Ocean but also south along the continental shelf. The researchers’ findings are based on computer models and on the presence of massive seafloor scars believed to have been left as the icebergs scraped the ocean bottom. The meltwater discharge may also have caused a temporary reversal in surface ocean currents. Now that the Greenland ice sheet is in a period of rapid melt, with large icebergs calving off, researchers are working to understand how that influx of cold fresh water will affect present-day ocean circulation patterns and, possibly, global climate.

New smart device looks like tiny telescope

13 October 2014

MIT Technology Review: Besides smart phones, smart glasses, and smart watches, another smart device may soon hit the market: the Loupe. Resembling a tiny telescope, the Loupe is a cylinder the size of a lipstick tube that the user can hold up to one eye to view a kaleidoscope-like display of icons for Twitter, Facebook, Gmail, and so on. Touch electrodes on the exterior allow the user to manipulate the images on the screen, and a manual focusing ring sits near one end. The Loupe, named for the magnification device used by jewelers, is the latest in a wave of wearable technology that provides constant access to messages, news, and updates. A prototype of the device was presented this month by Nokia at the ACM User Interface Software and Technology Symposium in Honolulu, Hawaii.

Science and engineering startups see growth in venture capital funding

13 October 2014

New York Times: In 2008, investment in industrial and energy startups reached $4.64 billion. For biotechnology companies, investment reached $5.14 billion. Those were record highs in those sectors. By 2013, the level of investment had dropped dramatically. Now, however, it appears that venture capitalists are again interested in funding science and engineering startups. In the first half of 2014, industrial and engineering companies received $1.24 billion, twice as much as in the same period in 2013. In biotech, $2.93 billion was invested, a 26% increase. In comparison, investment in software companies has continued to grow. In 2013, $11.2 billion was given to software companies, 85% more than was invested in 2008. Many of the science and engineering companies that have been receiving funding focus on eco-friendly technologies or clean energy. One such company is Transatomic Power, founded in 2011 by scientists from MIT to develop small-scale molten-salt nuclear reactors. The company received $2 million in August from the Founders Fund, which had previously invested in Facebook and Spotify.

NIH announces awards for data processing

10 October 2014

Science: The National Institutes of Health has announced $32 million in awards as part of its Big Data to Knowledge initiative. The awards will fund researchers who are developing tools to analyze the large amounts of data being produced by modern biology research. One of the projects will combine independent sets of DNA samples, brain scans, and other data to make it easier to look for statistically significant variations associated with a range of neurological and psychological diseases.

Comet passing Mars to be studied by orbiters and rovers

10 October 2014

Los Angeles Times: On 19 October a comet will be passing 14 000 km from Mars, and NASA plans to use three Martian orbiters, two rovers, and several Earth-based and orbiting telescopes to examine it. Named Siding Spring, the comet was first spotted in January 2013 and is estimated to have a core between 0.8 km and 5 km wide. The gas cloud is 19 000 km across and its tail is 1 AU long. The window for observation will be relatively small, since the comet will be traveling 56.3 km/s as it passes Mars. Siding Spring appears to be on its first pass through the solar system, and its nearby route provides the first opportunity to observe up close an object from the Oort cloud. The observations may provide clues about the early formation of the solar system.

<em>Hubble</em> detects jet stream on exoplanet

10 October 2014

Ars Technica: The Hubble Space Telescope has seen temperature differentials on an exoplanet that suggests the planet's atmosphere has a jet stream. WASP-43b is Jupiter sized and has a 19.5-hour orbit around a relatively small parent star. That proximity puts the planet in a category known as hot Jupiter because of the heating from the star. Hubble imaged the planet in the near-IR and saw an asymmetry in the temperature distribution on the planet as it orbited the star. The researchers suggest that a jet stream carrying warm air eastward from the side of the planet facing the Sun would account for the asymmetry. The planet has an otherwise significant temperature difference between the dayside and nightside, which helped make the asymmetry visible.

Questions and answers with Martin Harwit

10 October 2014
In his latest book, the distinguished scientist and former director of the Smithsonian National Air and Space Museum explores the societal forces that have shaped astronomy.

Women in physics—a view from 1948

10 October 2014
One of Physics Today’s first articles advocated physics as a college major and a career for women.

Bionic arm transmits sense of touch to wearer

10 October 2014

BBC: For more than one year, two patients in the US have been wearing bionic arms that transmit electrical signals directly to their nerves, thus giving them a sense of touch. The prosthetics are loaded with sensors in 19 locations on the hand. The sensors send signal patterns to the wearer's nerves, which the brain is able to translate into tactile sensations. The patterns are sensitive enough that when the patients are blindfolded, they can identify different materials' textures. An interesting side effect of the prosthetic is that it has eliminated the occurrence of phantom limb syndrome, in which amputees feel pain or itching in the lost limb. Separately, a team of researchers in Sweden has developed a prosthetic that is attached directly to the bone, which could lead to long-term permanent prosthetic limbs.

EU backs down from labeling tar sands as more polluting

9 October 2014

Nature: Canada’s tar sands contain a vast amount of oil, second only to the oil reserves of Saudi Arabia. However, extracting the oil requires much more energy and water than is used in conventional oil mining. For that reason, the European Commission had tried to restrict the importation of tar sands oil by classifying it as more carbon intensive than other fuels. However, the commission has since backed down due to resistance from Canadian oil producers and certain member states that want to reduce their dependence on fuel from politically volatile areas such as Russia and the Middle East.

LHCb detects two new mesons

9 October 2014

New Scientist: In 2006, the BaBar experiment at the SLAC National Accelerator Laboratory found an energy peak in particle collision data but was unable to determine the cause. Now, the LHCb experiment at CERN has determined that the peak was caused by the creation of two new mesons—particles formed from a quark and an antiquark held together by the strong force. The two particles, named DS3*(2860)– and DS1*(2860)–, are both formed by the combination of a charm antiquark and a strange quark. Significantly, DS3*(2860)– is the first particle that includes a charm quark that has a spin of 3. This unique property gives a clear picture of the meson's configuration, which could provide a new source of information about the strong force.

Hawaiians protest building of giant telescope

9 October 2014

Los Angeles Times: On Tuesday protesters delayed the groundbreaking ceremony for the proposed Thirty Meter Telescope to be built on Hawaii’s Mauna Kea. The enormous telescope will have a mirror nearly one-third the size of a football field, will be 40% larger than either of the Keck telescopes already on Mauna Kea, and will have a resolution 12 times as sharp as that of the Hubble Space Telescope. Mauna Kea is one of the best sites in the world for astronomical observation because of its low humidity, lack of cloud cover, and minimal light pollution. However, native Hawaiians consider the ground sacred and say that with 13 observation facilities already, the area has too many telescopes.

MRI technique reveals early sign of cognitive decline

8 October 2014

Los Angeles Times: Arterial spin labeling uses MRI to track magnetically tagged water molecules in blood as it flows through the brain. Combined with neuropsychological testing, the technique revealed low blood flow to patients' posterior cingulate cortex some 18 months before any notable decline in their cognitive capabilities. The researchers used the technique on 148 test subjects who displayed no symptoms of cognitive decline. When the same subjects were tested 18 months later, 73 were diagnosed with "deteriorating cognitive function." A comparison of the brain scans of the test subjects with those of patients known to have mild cognitive decline revealed that even before all the people with cognitive decline were diagnosed, they were  showing signs of low blood flow. Although there is no known treatment for neurodegenerative diseases such as Alzheimer's, arterial spin labeling could provide an early detection method.

Lunar water may have come from the Sun

8 October 2014

New Scientist: Although the Moon has long appeared to be a desert, there is actually a lot of water contained in minerals in its soil. Three possible sources of that water have been proposed: comets and meteorites, cosmic rays, or the solar wind. To try to determine which source is most likely, Alice Stephant and François Robert of the National Museum of Natural History in Paris measured the amounts of hydrogen and deuterium in soil samples collected by two Apollo missions. Because the amount of deuterium depends on how far the source was from the Sun, the ratio of the two elements can indicate where they originated. From that information, the researchers conclude that nearly all of the water in the upper 200 nm of the Moon’s surface came from the solar wind. Furthermore, they say the amount from comets and meteorites is negligible. However, water located deeper than 200 nm in the lunar surface may come from cosmic rays, which can penetrate rock and cause chemical reactions deep below the surface.

Lunar water may have come from the Sun

8 October 2014

New Scientist: Although the Moon has long appeared to be a desert, there is actually a lot of water contained in minerals in its soil. Three possible sources of that water have been proposed: comets and meteorites, cosmic rays, or the solar wind. To try to determine which source is most likely, Alice Stephant and François Robert of the National Museum of Natural History in Paris measured the amounts of hydrogen and deuterium in soil samples collected by two Apollo missions. Because the amount of deuterium depends on how far the source was from the Sun, the ratio of the two elements can indicate where they originated. From that information, the researchers conclude that nearly all of the water in the upper 200 nm of the Moon’s surface came from the solar wind. Furthermore, they say the amount from comets and meteorites is negligible. However, water located deeper than 200 nm in the lunar surface may come from cosmic rays, which can penetrate rock and cause chemical reactions deep below the surface.

Measuring big <em>G</em> turns rivals into allies

8 October 2014

Nature: The constant that defines the gravitational effect between two objects, G, has one of the least precise values of all the fundamental constants. Known to just three significant figures, G was first defined more than 300 years ago by Isaac Newton. Now, research groups that have been working separately to measure G are beginning to work together. For the next two days at a conference at NIST in Gaithersburg, Maryland, researchers will be planning how to best measure G. The goal is to select a set of experiments that will be performed by multiple groups using similar equipment. Oversight will be provided by an independent team. One aspect that may be difficult in these financially pressed times is finding funding for the experiments.

Measuring big <em>G</em> turns rivals into allies

8 October 2014

Nature: The constant that defines the gravitational effect between two objects, G, has one of the least precise values of all the fundamental constants. Known to just three significant figures, G was first defined more than 300 years ago by Isaac Newton. Now, research groups that have been working separately to measure G are beginning to work together. For the next two days at a conference at NIST in Gaithersburg, Maryland, researchers will be planning how to best measure G. The goal is to select a set of experiments that will be performed by multiple groups using similar equipment. Oversight will be provided by an independent team. One aspect that may be difficult in these financially pressed times is finding funding for the experiments.

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