Physics Today Daily Edition
Nature: Based on geological evidence, the Sahara desert in northern Africa has been thought to be between 2 million and 3 million years old. However, studies of dune deposits in northern Chad and of dust and pollen in sediments from sea floors off northern Africa now indicate that the region may have experienced extended dry spells as long as 7 million to 8 million years ago. What could have caused that aridification is the subject of a recent study published in Nature. Zhongshi Zhang of the Bjerknes Centre for Climate Research in Norway and colleagues have ruled out major mountain-forming episodes, changes in Earth’s orbit, and excessive atmospheric carbon dioxide. Instead, climate simulations indicate that the African summer monsoon, which brought moisture from the tropical Atlantic to northern Africa, was weakened by the shrinking of the ancient Tethys Sea. Critics say the theory remains speculative because too little is known about the ancient geology of the region.
BBC: A chin strap made from a piezoelectric material generates electricity as wearers move their jaws. Designed by Aidin Delnavaz and Jeremie Voix of the École de Technologie Supérieure in Montreal, Canada, the proof-of-concept device can produce 18 µW of power after just 60 seconds of chewing. They say that to actually be useful, however, it will need to generate 20 times as much electricity, which could be achieved by simply increasing the amount of piezoelectric material in the strap. A 20-layer strap just 6 mm thick should be able to power an intelligent hearing protector, such as sound-canceling headphones that are used for communications in heavy industry or the military. It could also be used to power cochlear implants or other similar small electronics, but probably not anything as large as a smart phone.
Guardian: One of the goals Congress assigned NASA is to identify by 2020 at least 90% of the asteroids larger than 140 m in diameter that pass within 45 million km of Earth's orbit. A report by NASA's inspector general says that the agency will not meet that goal despite a 10-fold increase in funding over the last five years. So far, the report states, the agency has found just 10% of the asteroids believed to meet the given criteria. According to the report, the likely failure is due to understaffing and poor organization of detection efforts. The one major upside of the report is that 95% of the asteroids larger than 1 km have been found. Asteroids of that size could cause significant global destruction.
New Scientist: Although drinking-water wells near several hydraulic fracturing sites in Pennsylvania and Texas are increasingly becoming contaminated with hydrocarbons, the source is most likely leaky pipelines and boreholes, rather than the fracking process itself. Because fracking involves fracturing shale rock by pumping chemicals into the ground, it was feared that those chemicals, which can be toxic, or the natural gas that gets released might make its way into local water supplies. However, after studying the contaminants, Thomas Darrah of the Ohio State University and colleagues say they appear to be noble gases that have leaked as they were being piped to the surface. If so, improving the integrity of the equipment and better environmental monitoring could take care of the problem.
New York Times: Yesterday NASA announced that it is awarding contracts to two private companies, Boeing and Space Exploration Technologies (SpaceX), to shuttle US astronauts to the International Space Station. Since the retirement of the space shuttle in 2011, the US has been relying on Russia to carry US astronauts back and forth. Increasing political tensions between the two countries, however, have forced the US to seek an alternative. Over the next three years, teams for Boeing’s CST-100 and SpaceX’s Dragon 2 capsules will work to have them certified by NASA and make a test flight to the space station. Once certified, they are each guaranteed at least two missions. The decision marks the first step toward the privatization of human spaceflight. Boeing is already planning to coordinate with NASA to allow a paying tourist to occupy one of the seats on its shuttle, and both Boeing and SpaceX are working with another company that plans to launch private space stations into orbit.
Science: Last month a political scientist was fired from Los Alamos National Laboratory after he published a paper critiquing the US nuclear weapons policy. Although told he was being laid off for budgetary reasons, James Doyle claimed his dismissal was retaliatory and petitioned the Department of Energy. Now the head of the National Nuclear Security Administration, Frank Klotz, has requested that DOE inspector general Gregory Friedman review Doyle’s case to determine whether his termination “resulted, in whole or in part, from the publication in question or the views expressed in it.” The move has been lauded as a positive step toward ascertaining whether the independence and intellectual integrity of government employees are being adequately protected.
Wall Street Journal: On Monday, the University of California posted a plan that will be presented to the system's Board of Regents on Wednesday. The plan calls for the establishment of an independent $250 million venture capital fund to support startups based on student and faculty research. Although other universities have similar funds, the University of California's will be one of the largest and is backed by the system's $9 billion endowment. Concerns have already been raised, however, that the fund might unfairly favor certain areas of research or those that appear the most likely to be profitable.
MIT Technology Review: Spanish soccer team FC Barcelona is renowned for its implementation of a style of soccer known as tiki-taka, which is characterized by short passes and control of possession. Laszlo Gyarmati of the Qatar Computing Research Institute and his colleagues have now used network theory to analyze the style of play of FC Barcelona and the rest of the top-tier teams in England, France, Germany, Italy, and Spain. Using data collected during the 2012–13 season, they determined how often each team used one of the five possible three-pass combinations (denoted by ABAB, for two players passing back and forth; ABCA, ABAC, and ABCB for three players; and ABCD for four players). Gyarmati’s analysis revealed that Barcelona used significantly fewer ABCD and ABCA patterns and significantly more ABAB and ABCB patterns than the average of the teams in the Spanish league as well as of the teams in Europe.
Guardian: Public schools in Texas may receive new social studies textbooks that are deliberately misleading regarding climate change, according to a recent report by the National Center for Science Education. Among the NCSE’s concerns are that the proposed texts cast doubt on whether Earth is undergoing climate change, question whether the current warming is due to human causes, and include misinformation and scientific inaccuracies—for example, claiming that the ozone hole was caused by fossil-fuel emissions. The NCSE report also takes issue with the fact that the texts promote the views of the Heartland Institute, an ultraconservative US public policy think tank, over those of the United Nations’ Intergovernmental Panel on Climate Change, a world-renowned scientific international body. The proposed textbooks are up for a public hearing before the Texas State Board of Education. If approved, they could be in schools for at least a decade.
BBC: In the middle of the Amazon jungle, about 160 km (100 mi) from Manaus, Brazil, construction has begun on a 325-m tower for observing the behavior of the atmosphere high above the forest canopy. The Amazon Tall Tower Observatory is a joint Brazilian and German project that will partner with a similar tower already built in the Siberian tundra and with a network of smaller towers throughout the Amazon region. The tower will be equipped with sensors to track particulate concentrations and to observe the interactions and movements of different air masses above the forest. Because the Amazon jungle is a very sensitive ecosystem, tracking climate changes and carbon dioxide concentrations there may provide further clues into understanding Earth's climate.
Nature: The primary purpose of the spleen is to act as a blood filter. Now, Donald Ingber of the Wyss Institute for Biologically Inspired Engineering in Boston, Massachusetts, and his colleagues have created an artificial "biospleen" that uses magnetic nanoparticles to filter pathogens from blood. Ingber's team coated magnetic nanobeads with a modified version of mannose-binding lectin, a protein that binds to the sugars on the outside of bacteria, viruses, fungi, and their toxic byproducts. The researchers fed blood into the device in which the nanoparticles were present and then used a magnet to pull the particles out of the blood along with any pathogens that had become attached; then the filtered blood was fed back into the patient. The device was tested on rats that were infected with either Escherichia coli or Staphylococcus aureus. Use of the biospleen filter increased the survival rate from 14% to 89%. Analysis of the blood after it was filtered showed that more than 90% of the bacteria had been removed. Ingber believes the device could be useful for stabilizing patients so that the immune system can eliminate the remaining traces of the infections and for fighting viral infections such as Ebola and HIV.
New Scientist: The European Space Agency (ESA) has selected a landing spot for Rosetta's Philae lander near the head of comet 67P/Churyumov-Gerasimenko. The chosen spot, designated J, was one of five candidate sites and was selected because it was the "smoothest" option. Even with that description, photographs from Rosetta reveal that the area has scattered boulders and cliffs that could make the landing difficult. A public campaign will be held to select an official name for the landing site before Philae is released in mid-November. The lander will take panoramic pictures, perform analyses of gas and dust at the surface, and drill into the surface to attempt to reveal the nature of internal cometary material.
Wired: The 1491 Martellus map, now housed at Yale University, may have been used by Christopher Columbus when he planned his first voyage across the Atlantic Ocean in 1492. Although the 1.2-by-2.0-meter map has survived for five centuries, its paint and text have faded. Now researchers are using advanced multispectral imaging to reveal text in places where it is not visible to the naked eye. Because of uneven erosion and fading pigments, however, each section of the map requires a different wavelength of light. Using 12 different types of LED illumination ranging from UV to IR, the team has photographed the map in 55 overlapping tiles. Through extensive image processing and analysis, they hope to extract all the readable text by next year and make the images available on Yale’s Beinecke Digital Library website.
MIT Technology Review: Ceramics have now been used to create new nanoscale lattices that result in extremely light materials that are very strong but also return to shape after they are compressed. Julia Greer of Caltech and her colleagues had previously achieved that result with metals, but ceramics had been harder to manipulate on the nanoscale. The researchers developed the new ceramic material by using a technique called two-photon interference lithography to "print" nanoscale polymer cylinders into a lattice configuration. Then they coated the structure with a ceramic and etched away the base polymer, leaving a network of ceramic tubes. The researchers also showed how the thickness of the tube walls determines how the material fails under compression. When the walls are just 10 nm thick, the tubes collapse instead of fracturing under pressure, then they return to shape when the pressure is removed. The high surface area and low weight make them materials of interest for electronics and batteries.