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Updated: 2 weeks 3 days ago

Ancient conifer provides example of winged-seed evolution

16 March 2015
New Scientist: As early as 370 million years ago, conifer trees began to develop seeds with two wings, which enabled the seeds to catch the wind and travel farther from the parent tree. Over the next 100 million years, the seeds evolved to have just a single wing. Cindy Looy and Robert Stevenson of the University of California, Berkeley, caught a glimpse of that evolution in action through their study of one of the earliest known such conifers, Manifera talaris. Based on fossil evidence, they created paper models of the three known seed types—symmetric double-winged, asymmetric double-winged (with one large and one small, stunted wing), and single-winged. The researchers found that the single-winged seeds, which adopted an autorotating, helicopter-style spin, remained airborne the longest, and that the asymmetric double-winged seeds flew farther than the symmetric double-winged seeds.

Artificial chameleon

16 March 2015
Large refractive-index contrast and flexibility combine in a novel way to allow active control of perceived colors.

Congressional critic of NSF softens criticism of grant approval process

13 March 2015

Science: For the past two years, Representative Lamar Smith (R-TX) has criticized NSF for its peer-review-based grant approval process for funding research that does not support the national interest. Under his guidance a subcommittee of the House science committee has been examining a selection of grants issued by NSF over the past decade. However, in an interview on Wednesday, Smith said the investigation has led him to believe that NSF's grant approval process is indeed the best option for making such complex decisions.

Automated custom complex molecular synthesis

13 March 2015

Nature: Marty Burke of the University of Illinois at Urbana-Champaign and his colleagues have developed a system that may significantly simplify a time-intensive process for chemists: creating complex synthetic molecules. The computerized network of pumps and syringes manipulates a library of commercially available molecular compounds to combine them in the order programmed by the user. Similar techniques have been developed in the past, but Burke's machine includes a process that automates the removal of excess material and isolates the newly combined molecule for use in subsequent steps. The result is the first automatic system that can produce ring-shaped and branching molecules.

<em>Hubble</em> detects evidence of underground ocean on Ganymede

13 March 2015

BBC: Jupiter's Ganymede is the largest moon in the solar system and is also unusual in that it has a significant magnetic field. Joachim Saur of the University of Cologne in Germany and his colleagues have been using the Hubble Space Telescope to study Ganymede's magnetic field and aurora. The interactions between the magnetic fields of Jupiter and Ganymede cause wobbles in Ganymede's field that can be seen in the movements of the aurora. Saur's team compared their observations with various models of Ganymede's internal structure. They found that Jupiter's magnetic field creates a secondary fluctuation in Ganymede's aurora that would be easily explained by interacting with a body of saltwater. The Hubble data most closely match a model of the moon that includes a subsurface ocean, though that ocean could be anywhere from 100 km deep with a salt content of 5 kg/L to just 10 km deep with 50 kg/L salt concentration.

Wireless technique uses nanoparticles to stimulate brain

13 March 2015
New Scientist: Magnetic nanoparticles could one day replace the more invasive method of implanting electrodes to achieve deep brain stimulation. Polina Anikeeva of MIT and colleagues inserted the nanoparticles into the brains of three mice. When the researchers applied low-RF magnetic fields, the nanoparticles gave off heat as they worked to realign themselves. That heat prompted the brain’s TRPV1 neurons to fire and send out electrical signals. Unlike the use of electrodes, the new technique requires no implants or wires. Moreover, it could prove better at targeting specific areas of the brain, which is important for the treatment of such neurological disorders as Parkinson’s disease and depression.

Electron microscopy is beautiful

13 March 2015
A new coffee-table book of biological images prompts Physics Today’s online editor to look back in time.

Ultrasound potentially could become a treatment for brain cancer and Alzheimer's disease

12 March 2015

Science: A clinical test will begin this month in which ultrasound will be used to deliver chemotherapy drugs to treat brain cancer. Ultrasound will briefly open the blood–brain barrier, which normally prevents drugs from reaching the brain. The risk is that ultrasound has the potential to directly damage brain tissue, so testing the technique on humans may not be as successful as earlier tests performed on rodents. Separately, Sunnybrook Research Institute's Kullervo Hynynen, who first tested ultrasound's effect on the blood–brain barrier, and his colleagues have used the technique on the brains of mice and found it eliminated abnormal clumps similar to those present in patients with Alzheimer's disease. They reported that the cognitive ability of the treated mice was restored.

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12 March 2015

NASA magnetosphere mission to be launched tonight

12 March 2015

New York Times: A fleet of four identical spacecraft is set to be launched from Cape Canaveral, Florida, this evening aboard an Atlas 5 rocket. The satellites will assume a tetragonal formation in orbit above Earth as part of NASA's two-year, $1.1 billion Magnetospheric Multiscale mission to study the planet's protective magnetic field. That field protects Earth from the radiation of the Sun's solar wind. However, how the field reacts when struck by solar flares is poorly understood. The arrangement of the satellites will allow researchers to image the magnetic field in three dimensions.

New argument puts start of Anthropocene at 1610 CE

12 March 2015

BBC: The Anthropocene is a proposed geological era to mark the point at which humans first had a significant global effect. Officially, we are still in the Holocene, which began at the end of the last glaciation, roughly 11 500 years ago. Different moments in the past several hundred years have been put forward as the beginning of the new human-dominated era. Mark Maslin of University College London and his colleagues have now proposed that 1610 CE should be the start point for the Anthropocene because of changes in global sediments and ice. Maslin and his group say the changes were triggered after the discovery of the Americas by European explorers. As a result of European expansion, several crops moved between continents and introduced new pollens into sediments around the world. Additionally, diseases brought to the Americas killed a significant percentage of the population, which resulted in a large reduction in the amount of land being farmed and thus a huge drop in atmospheric carbon. The researchers' proposal is a counter to a popular alternative that uses the introduction and proliferation of nuclear weapons as the demarkation point. Later this year an international working group is expected to choose an official date for the beginning of the Anthropocene.

Questions and answers with Peter Pesic

12 March 2015
An expert physicist, pianist, and historian draws on all three fields to explain how science followed music.

Glaciers melt noisily into the sea

12 March 2015
A joint field and lab study has identified the principal source of noise in glacial fjords.

Chameleons change color via photonic crystals in their skin

11 March 2015
BBC: Photonic crystals, rather than colored pigments, appear to be the mechanism by which chameleons achieve their rapid and brilliant color changes. According to a new study, researchers at the University of Geneva found panther chameleons to have two layers of light-reflecting nanocrystals, called iridophores, in their skin. The size and spacing of the crystals are what determine the skin color: When the lizard is relaxed, the crystals are tightly packed and reflect light at short wavelengths, such as blue; when the animal gets excited, the spacing of the crystals widens and they reflect longer wavelengths, such as red. The deeper layer of iridophores appears to have larger crystals arranged in a more disordered fashion, such that they reflect a substantial portion of near-IR light. The researchers say that layer may serve to help keep the animal cooler, but more experiments are needed to determine exactly what function the second layer provides.

Bioelectric signals in embryos can affect brain cell growth

11 March 2015

Nature: Michael Levin of Tufts University in Medford, Massachusetts, and his colleagues have investigated the way bioelectric signals in animal cells can be altered during embryonic growth to trigger unusual results, such as the development of a functional eye in a tadpole's tail and additional legs on frogs. Now they have shown that changing voltage gradients across cell membranes in the brains of frog embryos can stimulate the growth of additional brain cells. Their approach is based on the fact that cells communicate with each other through voltage gradients. By adjusting communication between certain areas, Levin's team was able to stimulate unusual growth. In the case of the brain cell study, the stimulated growth was even enough to overcome genetic mutations that normally resulted in brain defects.

Newly discovered dwarf galaxies could provide dark-matter clues

11 March 2015

Wired: A team of researchers from the University of Cambridge has discovered nine objects that appear to be dwarf galaxies in orbit around the Milky Way. It is the first such discovery since 2006. The objects were uncovered in data collected as part of an investigation into dark energy by the 570-megapixel Dark Energy Camera, which is mounted on the Victor M. Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in the Chilean Andes. The researchers have confirmed that three of the objects are dwarf galaxies; the other six could be either dwarf galaxies or star clusters with similar properties. The objects are located in the same area as both the Large and Small Magellanic Clouds, with the closest being about 97 000 light-years away and the farthest 1.2 million light-years. Because dwarf galaxies are 99% dark matter, they present an excellent opportunity to study the mysterious substance.

China to build two more nuclear reactors

11 March 2015
Wall Street Journal: Nuclear power is taking off in China, where two new reactors have just been approved for construction at the Hongyanhe nuclear power plant, near the city of Dalian. The country currently has 24 working reactors and 25 more under construction. Despite a slowdown in new nuclear construction following Japan's 2011 Fukushima Daiichi nuclear disaster, the Chinese government appears to have renewed its commitment to decreasing the country’s reliance on coal for electricity generation. New projects will be necessary for China to achieve its goal of more than doubling its current 20 gigawatts of installed nuclear power by 2020, to a total of 58 gigawatts. Besides using reactor models from other countries, including France, Russia, Canada, and the US, China has been developing its own reactors for potential export.

<em>New York Times</em> spotlights Iranian nuclear bomb technical “riddle”

10 March 2015
Iran reportedly dodges all but one of the International Atomic Energy Agency’s “dozen sharp questions on bomb design.”

Research on artificial photosynthesis makes progress

10 March 2015

MIT Technology Review: The Joint Center for Artificial Photosynthesis (JCAP) was established by the Department of Energy in 2010 as one of the agency's Innovation Hubs. Now the center's researchers have demonstrated a device that uses solar energy to electrolyze water. Electrolysis produces hydrogen gas, which can be stored and used to generate electricity. With conventional electrolysis, it costs between $10 and $20 to produce the amount of hydrogen fuel equivalent to one gallon of gasoline. Solar electrolysis could reduce that cost to $2–4, according to JCAP director Nathan Lewis. The system that JCAP developed combines electrolysis catalysts with solar cells to produce a less complex system of electrodes that have a lifetime of 1000 hours. Although that is not long enough for commercial devices, it shows significant progress. However, the $122 million originally provided to JCAP will run out later this year unless Congress provides more funding.

Florida DEP employees told not to use terms “climate change” and “global warming”

10 March 2015

Miami Herald: In 2011, Governor Rick Scott took office in Florida and appointed Herschel Vinyard Jr as the director of the state’s Department of Environmental Protection (DEP). According to many DEP employees, shortly thereafter they were instructed to stop using phrases such as “climate change” and “global warming” in official documents and statements. However, both Tiffany Cowie, the DEP’s press secretary, and Jeri Bustamante, Scott’s spokeswoman, have denied that any such policy was ever put in place. Scott has previously said that he was not convinced by the evidence for climate change and also that he is “not a scientist.” Florida is under severe threat from the effects of climate change; up to 30% of its beaches are predicted to be submerged by the end of the century as sea levels rise.

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