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Updated: 3 hours 57 min ago

Bio-inspired adhesive works underwater

6 October 2014

Ars Technica: Adhesives that form bonds while immersed in water would have many uses, especially in biomedical applications. To come up with such a substance, researchers have been studying sea-dwelling organisms, such as mussels and algae, whose secretions have naturally adhesive properties. Two different types of adhesive substances were found: One uses a chemical that links proteins together and is thus considered “sticky,” and the other uses an amyloid protein assembly that forms dense fibers. When combined, the sticky proteins enhanced the diameter of the fibers, which increased the surface contact area and improved adhesion. In addition, how the material interacts with different surfaces, such as silica, gold, and polystyrene, appears to depend on the interaction between the fibrous and sticky parts.

Two studies focus on ocean waters as heat sink

6 October 2014

Science: Although Earth’s oceans are as important to global climate as the atmosphere, they have not been as well studied. Two areas of particular concern are the waters of the Southern Hemisphere and those of the deep ocean, below 2000 m. Paul Durack of Lawrence Livermore National Laboratory and colleagues used satellite measurements of sea-level height to estimate ocean temperature—as water warms, it expands. According to their model simulations, estimates of the heat stored in the upper 700 m of the ocean since 1970 have been too low, due largely to the poor sampling data from the Southern Hemisphere. Another group of researchers, led by William Llovel of the Jet Propulsion Laboratory, looked at warming in the deep ocean since 2005. Because most temperature data come from buoys, more is known about water temperature in the top 2000 m, and much less is known about the temperature of the rest of the ocean, which can descend as deep as 6000 m. Comparing the available data with global sea-level rise since 2005, the researchers estimate that the deep ocean has barely warmed over the past decade. Both studies point up the need for more data, which may soon be provided by a new fleet of research buoys, dubbed Deep Argo.

Two studies focus on ocean waters as heat sink

6 October 2014

Science: Although Earth’s oceans are as important to global climate as the atmosphere, they have not been as well studied. Two areas of particular concern are the waters of the Southern Hemisphere and those of the deep ocean, below 2000 m. Paul Durack of Lawrence Livermore National Laboratory and colleagues used satellite measurements of sea-level height to estimate ocean temperature—as water warms, it expands. According to their model simulations, estimates of the heat stored in the upper 700 m of the ocean since 1970 have been too low, due largely to the poor sampling data from the Southern Hemisphere. Another group of researchers, led by William Llovel of the Jet Propulsion Laboratory, looked at warming in the deep ocean since 2005. Because most temperature data come from buoys, more is known about water temperature in the top 2000 m, and much less is known about the temperature of the rest of the ocean, which can descend as deep as 6000 m. Comparing the available data with global sea-level rise since 2005, the researchers estimate that the deep ocean has barely warmed over the past decade. Both studies point up the need for more data, which may soon be provided by a new fleet of research buoys, dubbed Deep Argo.

Measuring atmospheric carbon dioxide from space

6 October 2014
If we can account for the confounding effects of aerosols, satellite-based measurements of CO2 will improve our understanding of Earth’s carbon cycle.

Emergent effect creates quasi-Majorana particles

6 October 2014

Nature: Particles that are their own antiparticles were predicted by Ettore Majorana in 1937. None have been found in particle-physics experiments so far, but hints of Majorana-like quasiparticles have been seen in a condensed-matter system of strongly interacting electrons. Further, stronger evidence of the quasiparticles comes from a new experiment performed by Ali Yazdani of Princeton University and his colleagues. To create the quasiparticle, they placed a chain of iron atoms on top of a superconductor in such a way that the electrons in the iron atoms paired off. Each pair coordinated spins so that one of the electrons acted like a positron (the antielectron particle). The arrangement left unpaired electrons at both ends of the chain, which forced those two electrons to individually behave as both an electron and a positron. The finding strengthens the idea that true Majorana particles could exist outside of superconductors.

Emergent effect creates quasi-Majorana particles

6 October 2014

Nature: Particles that are their own antiparticles were predicted by Ettore Majorana in 1937. None have been found in particle-physics experiments so far, but hints of Majorana-like quasiparticles have been seen in a condensed-matter system of strongly interacting electrons. Further, stronger evidence of the quasiparticles comes from a new experiment performed by Ali Yazdani of Princeton University and his colleagues. To create the quasiparticle, they placed a chain of iron atoms on top of a superconductor in such a way that the electrons in the iron atoms paired off. Each pair coordinated spins so that one of the electrons acted like a positron (the antielectron particle). The arrangement left unpaired electrons at both ends of the chain, which forced those two electrons to individually behave as both an electron and a positron. The finding strengthens the idea that true Majorana particles could exist outside of superconductors.

Snowflake-like network design minimizes downtime and repair difficulty

6 October 2014

New Scientist: Large networks such as the power grid and the internet make use of redundancy to reduce the effects of damage to the network. Redundancy is generally expensive and can be difficult to maintain, but the cheaper alternative of fixing broken connections as needed can leave areas without network connection until they are repaired. To minimize the difficulty of making repairs, Robert Farr of the London Institute for Mathematical Sciences and his colleagues have determined that the ideal network design is a snowflake-like pattern. Starting with an arrangement of square or triangular nodes, they found that the best way to connect them was to have primary branches that have no more than two levels of branches below them. That topology allows each node to be connected on all but one side, meaning that connection failures were contained and that repairs were easy to make. Farr's team now hopes to apply the idea to real-world situations to determine how adaptable it is to changing conditions.

Study refutes theory that genetic diseases occur earlier in children than in their parents

3 October 2014

Nature: Genetic prion diseases, such as Creutzfeldt–Jakob disease, occur when inherited genetic mutations cause a person’s prion proteins to fold incorrectly. So far such diseases have proven to be untreatable and fatal. Last year a paper in the journal PLOS ONE reported that successive generations die younger of such inherited diseases. That finding has now been refuted by a computational scientist at Massachusetts General Hospital in Boston. Eric Minikel was inspired to look more closely at the issue because his wife carries the genetic mutation for fatal familial insomnia, another genetic prion disease. He persuaded the four leading prion centers in the world to check their data for sampling bias. He reasoned that because such genetic mutations have only been discovered relatively recently, in1989, most of the data collected would cover just two generations—parents and their children. Over such a short time period, if both parents and children developed the same disease, the parents would have had to be older at age of onset. However, when more information on the life spans of multiple generations of a family was available, there was no indication that the age of onset of such diseases was decreasing.

Space satellites find more mountains on Earth’s ocean floors

3 October 2014

BBC: “We know much more about the topography of Mars than we know about the sea floor,” says Dietmar Müller of the University of Sydney. The problem has been that standard land-based techniques for mapping terrain don’t work underwater and ship-borne echo sounders have been able to scan only limited stretches of the ocean floor. Now Müller and his colleagues have discovered thousands more underwater mountains through the use of the improved radar technologies of the Jason-1 and CryoSat-2 satellites. Better understanding of the topography of the ocean floor is important for furthering our understanding of its influence on global climate, for fisheries management and conservation, and for many other reasons. Although current satellite data have proven extremely useful, the researchers hope a dedicated mission will be approved to more thoroughly map the shape of the sea floor.

House Science Committee continues unusual review of NSF grants

3 October 2014

Science: Soon after Lamar Smith (R-TX) became head of the House  Committee on Science, Space, and Technology last year, he requested that NSF allow the committee to review a collection of grants that NSF had awarded. However, as NSF was in the process of choosing a new director, Smith waited to press the issue. When France Córdova was named to the post earlier this year, Smith again submitted his request. However, Córdova let him know that because of concerns over privacy regarding the grant process, she was setting certain stipulations: Congressional staffers would have to come to NSF headquarters to access the files, the names of the grant reviewers would be redacted, and no copies of the documents could be made. Under this agreement, committee staff members have been evaluating 50 grants in a process that Smith estimates is only 5% complete. He says that the goal is to ensure that the tax-payer-funded grants are being awarded to research that is in the national interest. Many of the grants under review are in the area of the social sciences or involve research outside the US. The review has drawn criticism from Democrats and researchers, who say that politics is being injected into what is normally a scientific process for determining grant winners.

First carbon-capturing coal plant begins operation

3 October 2014

MIT Technology Review: As reported earlier this year, the first commercial-scale system for carbon capture and storage has begun operation at a coal power plant in Saskatchewan, Canada. The 110-MW power plant has been retrofitted to capture 90% of its carbon dioxide emissions. It then pumps the CO2 into nearby oil fields to help extract the oil and, at the same time, store the gas in the rock underground. Even with the 90% reduction in emissions, however, the plant still produces the same amount of carbon pollution as a natural gas plant—roughly 150 tons of CO2 per gigawatt-hour.

Nobel predictions for 2014

3 October 2014
Physics Today’s online editor tries to guess who might win all six of this year’s prizes.

NIH awards $46 million as part of BRAIN initiative

2 October 2014

MIT Technology Review: Francis Collins, director of the US National Institutes of Health, announced earlier this week that the agency would be distributing $46 million in research awards as part of the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative. The funds will be distributed to 58 research groups working on projects that include a wearable PET scanner, laser control of neuron activity, and electrodes that can detect the presence of dopamine in living brains. One of BRAIN's goals is to develop technologies for better understanding how the brain operates. Because of the complexity of the brain, many researchers think that the technology needed to make immediately useful discoveries does not yet exist. The initial investment by BRAIN may help rectify that situation.

Documenting the evolution of metrology—a review

2 October 2014
A DVD released this year chronicles the history and process of measurement standards.

Icy cyanide cloud detected over Saturn’s moon Titan

2 October 2014

Nature: Over the past two years, a cloud has been forming over the south pole of Titan, the largest of Saturn’s moons. The discovery was not unexpected, as the southern hemisphere has been shifting to winter, and a cloud had appeared over the north pole a decade earlier when the northern hemisphere was experiencing winter. However, data from NASA’s Cassini spacecraft indicate that the cloud is much higher, at 300 km, than expected. It is also composed of micrometer-sized particles of hydrogen cyanide ice, indicating that the air temperature is at least 100 K colder than predicted. Because the cloud only appeared two years ago, and there was no indication of cyanide ice at that time, the atmospheric temperature must be dropping relatively rapidly. The surprising findings indicate that Titan may be more dynamic than researchers thought and that global-circulation models of Titan’s atmosphere may need to be revised.

Connection found between cosmic-ray and high-energy-neutrino source

2 October 2014
New Scientist: Earth is perpetually bombarded by cosmic rays—a mix of gamma rays, protons, neutrinos, and other high-energy particles. The sources of the particles are hard to identify because electrically charged cosmic rays are affected by Earth's magnetic field and neutrinos only rarely interact with other matter. However, a possible connection has been found thanks to an explosion that occurred near the center of the Milky Way. On 9 February 2012, the Chandra X-Ray Observatory detected an explosion of x rays from near where a supermassive black hole is believed to exist at the center of the galaxy. Three hours later, the IceCube neutrino detector in Antarctica detected some of the highest-energy neutrinos ever seen that also appeared to originate from the center of the Milky Way. The time difference suggests that the x-ray emitting particles and the neutrinos were accelerated by the same, as-yet-unknown phenomenon. Even if the accelerator is identified, there are likely several other sources of both cosmic rays and neutrinos, both inside and outside the Milky Way.

Large rectangular feature below lunar surface indicates tectonic activity

2 October 2014

BBC: Until 2012, when NASA’s GRAIL mission mapped the Moon’s gravity gradients, it was assumed that the Procellarum—a large lunar mare on the Moon’s near side—had been formed as the result of an ancient giant impact with a smaller celestial body. However, by looking more closely at variations in the pull of gravity over the Moon’s surface, researchers were able to detect an excess of mass that they attributed to the presence of basaltic lava filling rift valleys. Because of the presence of large amounts of uranium, thorium, and potassium in the Procellarum region, they propose that early in the Moon’s existence those radioactive elements would have caused the crust to heat up and expand. Subsequent cooling would have then caused the surface to contract and led to the creation of large rifts, which later were filled in by volcanic lava. The theory would explain the Procellarum’s distinct rectangular shape, as opposed to the more circular shapes of other lunar maria.

Martin L. Perl

2 October 2014

UV light and peptides hit a triplet

2 October 2014
The human body is pretty good at protecting itself from ultraviolet radiation but it needs help.

Low-frequency background noise may damage ears

1 October 2014

Science: Although prolonged exposure to loud noises has long been known to lead to hearing loss, a new study shows that low-frequency sounds may also cause damage. Neurobiologists at the Ludwig-Maximilians University in Munich exposed 21 volunteers to a deep, vibrating noise in the 30-Hz range—barely audible to the human ear. Such noise levels are regularly generated by wind turbines, roaring crowds, and jet engines. Then the researchers measured the spontaneous otoacoustic emissions (SOAEs) produced by the participants’ inner ears. Healthy ears regularly emit SOAEs; damaged ears do not. The researchers found that just 90 seconds of exposure to low-frequency sound caused participants’ SOAEs to start oscillating erratically. Although that is not proof that such sounds can cause permanent damage, the effect may leave the ear temporarily more prone to damage, they say.

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