Physics Today Daily Edition
Ars Technica: One process developed to capture the carbon dioxide emitted by power plants generally uses amines to separate the CO2 molecules from the other gases being released. Certain amine solutions require high temperatures to work effectively. Because they use some of the plant’s generated heat, the amount of heat available to generate electricity is reduced, and so is the plant’s efficiency. Others amines can work at lower temperatures, but are so slow that the amount of CO2 that they trap is reduced. Industry researchers wanted to combine the lower temperature amines with carbonic anhydrase, an enzyme many organisms use for the fast transport of CO2. However, the enzyme does not function well in hot and acidic conditions, such as those found in coal power plants. Now a group of researchers has shown that it is possible to customize the enzyme via controlled mutations to make it resistant to those conditions. By artificially selecting versions of the enzyme that showed increased resistance, they were able to significantly increase the effectiveness of the enzyme even under extreme conditions. When the modified enzyme was introduced to the slow amine solution, it captured carbon 25 times faster.
Nature: From 2010 to 2012, sounding rockets carried the Cosmic Infrared Background Experiment (CIBER) into space multiple times to look at the IR background, which is made up, in part, of myriad distant and unresolved galaxies. After eliminating light from the Milky Way, Michael Zemcov of Caltech and his colleagues found that a significant portion of the light CIBER detected was not redshifted enough to have come from old galaxies. When they extrapolated the data to cover the entire universe, they realized that the light detected couldn’t have come from known galaxies. That finding suggested that the source of the light was stars scattered in the space between galaxies. Those stars could have escaped low-mass galaxies or been ejected by collisions of galaxies. However, the stars are too faint to be detected individually. By Zemcov and colleagues’ calculations, the number of extragalactic stars could equal the number of stars in all the known galaxies.
Telegraph: When someone reports having seen a ghost, it may really be just a figment of the imagination, according to a recent study published in Current Biology. Researchers in Switzerland set up a robot system, in which the human subjects used their index finger to control the movements of a master robot. Those movements were relayed to a slave robot located behind the human subjects that touched their back. That sensation alone felt weird enough to the test subjects, but it became stranger still when a delayed reaction was introduced between the subjects touching the robot button and their backs being touched. Then the subjects reported feeling as if they were being watched and touched by invisible people. The researchers say that the phenomenon occurs when the functioning of the human brain gets disrupted, which can happen when subjected to such conditions as illness, extreme cold, oxygen deprivation, or exhaustion. Two of the 12 participants were so upset by the experiment that they asked that it be stopped.
BBC: At least one species of bat has been observed to emit sound signals that interfere with its competitors so it can snatch food. Aaron Corcoran of Wake Forest University in North Carolina decided to study Mexican free-tailed bats after noticing one member of the species appearing to jam the echolocating signal of another in the hunt for insects. Corcoran and colleagues illuminated the night sky and set up a camera to record the bats’ movements and microphones to record their sounds. They found that when hunting for food, the bats were able to produce just the right frequency to interfere with others’ signals. Corcoran says the finding was unexpected and he plans to look into whether the behavior is unique to that particular species.
Science: Among the 146 referenda and initiatives on the ballot Tuesday in numerous states and the District of Columbia, several were directly related to science, engineering, or the environment. In Colorado and Oregon, referenda requiring genetically modified foods to be labeled as such were voted down. Maine approved measures to fund an animal and plant disease and insect control lab, a genomics and disease research center, and the modernization and expansion of a biological laboratory specializing in tissue repair and regeneration. In Michigan, voters were against allowing the hunting of wolves. However, the state’s legislature may have the final say, depending on whether the state courts uphold a measure the legislators passed to circumvent Tuesday’s vote.
MIT Technology Review: The brain is often referred to as a parallel computer because it can run many different processes simultaneously. Harris Georgiou of the National Kapodistrian University of Athens in Greece and his colleagues have now used functional magnetic resonance imaging (fMRI) to determine how many independent processes are running and on what scale. In Georgiou's experiment, the fMRI scanner represented the brain as a 60 × 60 × 30 grid of 3D voxels, with each voxel embodying roughly 3 million neurons and each neuron having tens of thousands of connections to its neighbors. In comparison, current attempts to model brain functionality use computer chips containing only about 1 million neurons, each with just 256 connections. Using oxygenation in each voxel as a measure of neuronal activity, Georgiou's group studied the brains of test subjects performing visuo-motor and reasoning activities of differing difficulties. The fMRI revealed that complex visuo-motor tasks activated roughly 50 sections of the brain at a level of structure above that of individual neurons.
Telegraph: The ability of modern medical devices, such as pacemakers, to wirelessly connect to computers has allowed doctors and other medical professionals to more easily monitor them. However, US security experts say that such accessibility could also make them easy prey for terrorists. According to the Department of Homeland Security, there are some 300 medical devices on the market today that have unchangeable passwords. That lack of security could allow a person with malicious intent to gain access and change the settings, perhaps to send a series of shocks to accelerate the heartbeat and cause a fatal arrhythmia or to prevent the device from functioning properly. Besides the development of noise shields and other methods of blocking access, software is being written to look out for any unusual activity or tampering. So far there have been no reports of deaths or injuries caused by such a bodily cyberattack.
Nature: The process of plasma wakefield acceleration was first proposed 30 years ago but has only recently become technically feasible. Now, Michael Litos of SLAC's National Accelerator Laboratory in Menlo Park, California, and his colleagues have built a functioning accelerator capable of producing an energy gain per unit of length that is 1000 times higher than even the Large Hadron Collider at CERN. The technique fires paired bunches of electrons into plasmas. As the first bunch of electrons enters the plasma, its charge pushes the electrons in the plasma away from the beam path, which creates a positively charged channel. That area pulls the plasma electrons back toward the center and, in doing so, accelerates the second bunch of electrons that is following behind the first. The technique works only for linear accelerators, which means it could be adapted to shrink the proposed International Linear Collider from 30 km in length to just 4.5 km. Smaller accelerators would also be able to be easily installed at universities and even hospitals where they could be used for medical imaging.
Nature: A microscopist fired from his job at California State University, Northridge, is now suing the university, claiming wrongful termination. Mark Armitage says that he lost his job because of his belief in creationism. In 2012 he unearthed a fossil triceratops horn in Montana that contained not only fossilized bone but also soft tissue. The discovery of the soft tissue led him to date the specimen as being just thousands of years old—which would place it at the time of the biblical flood—rather than the millions of years supported by most evolutionary biologists. Although he refrained from stating his views on the age of the fossil in his paper, which was published in 2013 in the journal of cell and tissue research Acta Histochemica, he says he was fired because fellow faculty members were upset that a creationist got published in a legitimate scientific journal. Specialists in US labor law say his claim of religious intolerance may not hold up in court.
Science: Objects at the center of the Milky Way are obscured by dense clouds of gas and dust. One of those objects, G2, was detected to be on a near-collision course with the supermassive black hole believed to be at the center of the Milky Way. Initial observations suggested that G2 was a gas cloud, so it was expected that, as it neared the black hole, it would be torn apart and release bright radiation. But it didn't. Andrea Ghez of UCLA and her colleagues used the Keck Observatory to study G2 as it passed by the galactic center. Because IR images revealed that G2 had continued along its orbit, Ghez's team concluded that G2 must instead be a large star hidden inside a cloud of dust. Their calculations indicate that the star has a mass twice that of the Sun, but a radius 100 times larger. Other researchers argue that even if G2 were just a cloud of gas, it would have stretched and compressed without any significant release of radiation. Further evidence is likely necessary to clearly prove which hypothesis is correct.
Los Angeles Times: Although humans have been studying penguins for some time, any interaction with the animals has been shown to cause them stress, resulting in faster heart rates, attempts to escape, and interference with their mating and breeding. So to get a closer look with minimal disruption, a team of researchers at the University of Strasbourg in France decided to try using a small, four-wheeled rover dressed up to look like a fluffy penguin chick. When the rover was tested on a colony of emperor penguins within Adélie Land, it was not only accepted into the colony but was also allowed to huddle with a “crèche” of chicks. The results were promising enough that similar robots may be designed to investigate other kinds of animals, including those that swim or fly.
BBC: Fabiola Gianotti, who has served as project leader of the LHC's Atlas collaboration since 2009, has been chosen by CERN's managing council to take over the directorship of the organization in 2016. Gianotti earned her doctorate from the University of Milan, Italy, in 1987 and began working at CERN the same year. She will be the first female director of the international institution. Gianotti will replace Rolf Heuer, who oversaw the beginning of operations at the LHC. Because of her key role in the Atlas collaboration, Gianotti was one of the two researchers who announced the 2012 detection of the Higgs particle.
MIT Technology Review: A computer chip is being developed by HRL Laboratories that uses a series of silicon neurons to transmit, receive, and interpret electrical signals. Its design has been modeled on the small size and energy efficiency of the brain. In a recent test, a prototype, consisting of 576 silicon neurons, was mounted on a tiny drone that was flown into three rooms. Upon entering each room, the chip gathered data from the craft’s optical, ultrasound, and IR sensors. The data triggered a pattern of electrical activity in the neurons that the chip then used to recognize the room again when the drone reentered it. By mimicking the way the brain learns, the chip could allow drones to analyze video and sensor data without human intervention. Such smart sensors could be incorporated into cars, airplanes, and other systems.
Nature: The extent to which human understanding of probability is innate has been extensively debated. In a new study, Vittorio Girotto of the University IUAV in Venice, Italy, and his colleagues attempted to clarify the issue by comparing the probabilistic reasoning abilities of formally educated adults with those who had received no formal education. Regardless of education level, the subjects were found to be equally capable of predicting that blue would be the most likely color of chip to be pulled out of a basket containing three blue chips and one green chip. Both groups also correctly predicted that a red shape was the most likely to be drawn from a mix of four red squares, three green circles, and one red circle, and they all updated their prediction to green when told that the shape being drawn was a circle. Both groups were also equally successful when betting whether two tokens drawn from a mixed collection would be the same color. Girotto's team believes that the way problems are presented to people can affect how successful they are at predicting the outcomes. Whereas written problems were used in earlier studies claiming that people showed no inherent ability with probabilities, Girotto and colleagues used visual tests. Girotto also notes that because he and his team did not take advanced reasoning into account, the results should not be overly generalized.
BBC: Each year in the US, more than 3000 button-shaped batteries are ingested, primarily by children. When exposed to the fluids of the digestive system, batteries can release current and set off chemical reactions that can seriously injure or kill the person. To prevent that happening, Jeff Karp of the Brigham and Women's Hospital in Boston and his colleagues have invented a coating that keeps the batteries from generating current unless squeezed. They covered the negative terminal of the battery with a 1-mm-thick layer of silicone laced with small particles of metal and then covered the rest of the battery with a sealant. When the battery is squeezed, the silicone compresses and the metal particles get close enough to allow the electrons from the battery to flow through the material via quantum tunneling. They compared the battery's behavior with that of an uncovered battery by placing each in a beaker of simulated stomach fluid. They also tested the covered battery in the digestive systems of live pigs.