August 20th, 2016
By Alton Parrish.
Making an assistive robot partner expressive and communicative is likely to make it more satisfying to work with and lead to users trusting it more, even if it makes mistakes, a new study suggests.
But the research also shows that giving robots human-like traits could have a flip side – users may even lie to the robot in order to avoid hurting its feelings.
Researchers from University College London and the University of Bristol experimented with a humanoid assistive robot helping users to make an omelette. The robot was tasked with passing the eggs, salt and oil but dropped one of the polystyrene eggs in two of the conditions and then attempted to make amends.
The aim of the study was to investigate how a robot may recover a users’ trust when it makes a mistake and how it can communicate its erroneous behaviour to somebody who is working with it, either at home or at work
The study suggests that a communicative, expressive robot is preferable for the majority of users to a more efficient, less error prone one, despite it taking 50 per cent longer to complete the task.
Users reacted well to an apology from the robot that was able to communicate, and were particularly receptive to its sad facial expression. The researchers say this is likely to have reassured them that it ‘knew’ it had made a mistake.
At the end of the interaction, the communicative robot was programmed to ask participants whether they would give it the job of kitchen assistant, but they could only answer yes or no and were unable to qualify their answers.
Some were reluctant to answer and most looked uncomfortable. One person was under the impression that the robot looked sad when he said ‘no’, when it had not been programmed to appear so. Another complained of emotional blackmail and a third went as far as to lie to the robot.
Adriana Hamacher, who conceived the study as part of her MSc in Human Computer Interaction at UCL, said: “We would suggest that, having seen it display human-like emotion when the egg dropped, many participants were now pre-conditioned to expect a similar reaction and therefore hesitated to say no; they were mindful of the possibility of a display of further human-like distress..
“Human-like attributes, such as regret, can be powerful tools in negating dissatisfaction but we must identify with care which specific traits we want to focus on and replicate. If there are no ground rules then we may end up with robots with different personalities, just like the people designing them.”
Professor Kerstin Eder, who leads the Verification and Validation for Safety in Robots research theme at the Bristol Robotics Laboratory and co-supervised Adriana’s project, said: “Trust in our counterparts is fundamental for successful interaction. Adriana’s study gives key insights into how communication and emotional expressions from robots can mitigate the impact of unexpected behaviour in collaborative robotics. Complementing thorough verification and validation with sound understanding of these human factors will help engineers design robotic assistants that people can trust.”
Adriana’s project was aligned with the EPSRC funded project Trustworthy Robotic Assistants, where new verification and validation techniques are being developed to ensure safety and trustworthiness of the machines that will enhance our quality of life in the future.
The research will be presented at the IEEE International Symposium on Robot and Human Interactive Communication (RO-MAN), taking place from 26 to 31 August in New York City, and published by the IEEE as part of the conference proceedings available via the IEEE Xplore Digital Library.
Paper
‘Believing in BERT: Using expressive communication to enhance trust and counteract operational error in physical Human-Robot Interaction’ by Adriana Hamacher, Nadia Bianchi-Berthouze, Anthony G. Pipe and Kerstin Eder in IEEE Conference Publications
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August 20th, 2016
By alton parrish.
Several thousand years ago, a star some 160,000 light-years away from us exploded, scattering stellar shrapnel across the sky. The aftermath of this energetic detonation is shown here in this striking image from the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3.
The exploding star was a white dwarf located in the Large Magellanic Cloud, one of our nearest neighboring galaxies. Around 97 percent of stars within the Milky Way that are between a tenth and eight times the mass of the sun are expected to end up as white dwarfs. These stars can face a number of different fates, one of which is to explode as supernovae, some of the brightest events ever observed in the universe. If a white dwarf is part of a binary star system, it can siphon material from a close companion. After gobbling up more than it can handle — and swelling to approximately one and a half times the size of the sun — the star becomes unstable and ignites as a Type Ia supernova
This was the case for the supernova remnant pictured here, which is known as DEM L71. It formed when a white dwarf reached the end of its life and ripped itself apart, ejecting a superheated cloud of debris in the process. Slamming into the surrounding interstellar gas, this stellar shrapnel gradually diffused into the separate fiery filaments of material seen scattered across this skyscape.
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August 19th, 2016
By Alton Parrish.
With the advent of the Internet of Things (IoT) era, strong demand has grown for wearable and transparent displays that can be applied to various fields such as augmented reality (AR) and skin-like thin flexible devices. However, previous flexible transparent displays have posed real challenges to overcome, which are, among others, poor transparency and low electrical performance. To improve the transparency and performance, past research efforts have tried to use inorganic-based electronics, but the fundamental thermal instabilities of plastic substrates have hampered the high temperature process, an essential step necessary for the fabrication of high performance electronic devices.
This image shows ultrathin, flexible, and transparent oxide thin-film transistors produced via the ILLO process.
As a solution to this problem, a research team led by Professors Keon Jae Lee and Sang-Hee Ko Park of the Department of Materials Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST) has developed ultrathin and transparent oxide thin-film transistors (TFT) for an active-matrix backplane of a flexible display by using the inorganic-based laser lift-off (ILLO) method. Professor Lee’s team previously demonstrated the ILLO technology for energy-harvesting (Advanced Materials, February 12, 2014) and flexible memory (Advanced Materials, September 8, 2014) devices.
The research team fabricated a high-performance oxide TFT array on top of a sacrificial laser-reactive substrate. After laser irradiation from the backside of the substrate, only the oxide TFT arrays were separated from the sacrificial substrate as a result of reaction between laser and laser-reactive layer, and then subsequently transferred onto ultrathin plastics (4μm thickness). Finally, the transferred ultrathin-oxide driving circuit for the flexible display was attached conformally to the surface of human skin to demonstrate the possibility of the wearable application. The attached oxide TFTs showed high optical transparency of 83% and mobility of 40 cm^2 V^(-1) s^(-1) even under several cycles of severe bending tests.
Professor Lee said, “By using our ILLO process, the technological barriers for high performance transparent flexible displays have been overcome at a relatively low cost by removing expensive polyimide substrates. Moreover, the high-quality oxide semiconductor can be easily transferred onto skin-like or any flexible substrate for wearable application.”
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August 19th, 2016
By Alton Parrish.
Permanently shadowed regions capable of accumulating surface ice were identified in the northern hemisphere of Ceres using images taken by NASA’s Dawn mission combined with sophisticated computer modeling of illumination.
Scientists with NASA’s Dawn mission have identified permanently shadowed regions on the dwarf planet Ceres. Most of these areas likely have been cold enough to trap water ice for a billion years, suggesting that ice deposits could exist there now.
“The conditions on Ceres are right for accumulating deposits of water ice,” said Norbert Schorghofer, a Dawn guest investigator at the University of Hawaii at Manoa. “Ceres has just enough mass to hold on to water molecules, and the permanently shadowed regions we identified are extremely cold — colder than most that exist on the moon or Mercury.”
Permanently shadowed regions do not receive direct sunlight. They are typically located on the crater floor or along a section of the crater wall facing toward the pole. The regions still receive indirect sunlight, but if the temperature stays below about minus 240 degrees Fahrenheit (minus 151 degrees Celsius), the permanently shadowed area is a cold trap — a good place for water ice to accumulate and remain stable. Cold traps were predicted for Ceres but had not been identified until now.
At the poles of Ceres, scientists have found craters that are permanently in shadow (indicated by blue markings). Such craters are called “cold traps” if they remain below about minus 240 degrees Fahrenheit (minus 151 degrees Celsius). These shadowed craters may have been collecting ice for billions of years because they are so cold. This image was created using data from NASA’s Dawn spacecraft.
In this study, Schorghofer and colleagues studied Ceres’ northern hemisphere, which was better illuminated than the south. Images from Dawn’s cameras were combined to yield the dwarf planet’s shape, showing craters, plains and other features in three dimensions. Using this input, a sophisticated computer model developed at NASA’s Goddard Space Flight Center, Greenbelt, Maryland, was used to determine which areas receive direct sunlight, how much solar radiation reaches the surface, and how the conditions change over the course of a year on Ceres.
The researchers found dozens of sizeable permanently shadowed regions across the northern hemisphere. The largest one is inside a 10-mile-wide (16-kilometer) crater located less than 40 miles (65 kilometers) from the north pole.
Taken together, Ceres’ permanently shadowed regions occupy about 695 square miles (1,800 square kilometers). This is a small fraction of the landscape — much less than 1 percent of the surface area of the northern hemisphere.
The team expects the permanently shadowed regions on Ceres to be colder than those on Mercury or the moon. That’s because Ceres is quite far from the sun, and the shadowed parts of its craters receive little indirect radiation.
“On Ceres, these regions act as cold traps down to relatively low latitudes,” said Erwan Mazarico, a Dawn guest investigator at Goddard. “On the moon and Mercury, only the permanently shadowed regions very close to the poles get cold enough for ice to be stable on the surface.”
The situation on Ceres is more similar to that on Mercury than the moon. On Mercury, permanently shadowed regions account for roughly the same fraction of the northern hemisphere. The trapping efficiency — the ability to accumulate water ice — is also comparable.
By the team’s calculations, about 1 out of every 1,000 water molecules generated on the surface of Ceres will end up in a cold trap during a year on Ceres (1,682 days). That’s enough to build up thin but detectable ice deposits over 100,000 years or so.
“While cold traps may provide surface deposits of water ice as have been seen at the moon and Mercury, Ceres may have been formed with a relatively greater reservoir of water,” said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles. “Some observations indicate Ceres may be a volatile-rich world that is not dependent on current-day external sources.”
The findings are available online in the journal Geophysical Research Letters.
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August 18th, 2016
By Alton parrish.
Overeating can lead to health issues that can shorten one’s life, such as obesity, diabetes and heart disease. On the other end of the spectrum, several studies have shown that restricting calorie intake below what a normal diet would dictate may lead to a longer life. In an animal study, scientists now report in ACS’Journal of Proteome Research the metabolic reasons why these opposite diets may lead to such differences in longevity.
Researchers investigated the metabolic reasons behind why choosing a low-calorie diet could extend one’s lifespan.
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Calorie restriction with proper nutrition seems to help extend lifespans and delay the onset of age-related disorders by reducing what are called reactive oxygen species in the body. Research has shown that calorie restriction changes the levels of hormones and lipid metabolites, and alters energy metabolism. However, scientists still do not know the precise biochemical changes the body undergoes during calorie restriction, and no one has determined its long-term effects. So Huiru Tang, Yulan Wang, Yong Liu and colleagues set out to investigate the metabolic responses of mice placed on long-term, calorie-restrictive diets.
The group divided mice into four dietary categories — low-fat, low-fat with calorie restriction, high-fat and high-fat with calorie restriction — for more than a year. They then used nuclear magnetic resonance analysis to examine the metabolic effects in blood and urine samples. The researchers found that calorie restriction had a much bigger effect on metabolic outcomes than the amount of fat in the diet. Mice on higher calorie diets had increased oxidative stress, disturbed lipid metabolism, suppressed glycolysis and altered gut-microbial metabolites compared to those on the calorie-restricted regimens.
The researchers acknowledge funding from the Ministry of Science and Technology of China and the National Natural Science Foundation of China.
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August 17th, 2016
By Alton Parrish.
New water purification process is a potential boon to developing countries as well as soldiers and campers The simple new approach combines bacteria-produced cellulose and graphene oxide to form a bi-layered biofoam and is powered by the sun. .
Graphene oxide has been hailed as a veritable wonder material; when incorporated into nanocellulose foam, the lab-created substance is light, strong and flexible, conducting heat and electricity quickly and efficiently.
Now, a team of engineers at Washington University in St. Louis has found a way to use graphene oxide sheets to transform dirty water into drinking water, and it could be a global game-changer.
An artist’s rendering of nanoparticle biofoam developed by engineers at Washington University in St. Louis. The biofoam makes it possible to clean water quickly and efficiently using nanocellulose and graphene oxide.
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“We hope that for countries where there is ample sunlight, such as India, you’ll be able to take some dirty water, evaporate it using our material, and collect fresh water,” said Srikanth Singamaneni, associate professor of mechanical engineering and materials science at the School of Engineering & Applied Science.
A paper detailing the research is available online in Advanced Materials.
“The process is extremely simple,” Singamaneni said. “The beauty is that the nanoscale cellulose fiber network produced by bacteria has excellent ability move the water from the bulk to the evaporative surface while minimizing the heat coming down, and the entire thing is produced in one shot.
“The design of the material is novel here,” Singamaneni said. “You have a bi-layered structure with light-absorbing graphene oxide filled nanocellulose at the top and pristine nanocellulose at the bottom. When you suspend this entire thing on water, the water is actually able to reach the top surface where evaporation happens.
“Light radiates on top of it, and it converts into heat because of the graphene oxide — but the heat dissipation to the bulk water underneath is minimized by the pristine nanocellulose layer. You don’t want to waste the heat; you want to confine the heat to the top layer where the evaporation is actually happening.”
The cellulose at the bottom of the bi-layered biofoam acts as a sponge, drawing water up to the graphene oxide where rapid evaporation occurs. The resulting fresh water can easily be collected from the top of the sheet.The process in which the bi-layered biofoam is actually formed is also novel. In the same way an oyster makes a pearl, the bacteria forms layers of nanocellulose fibers in which the graphene oxide flakes get embedded.
“While we are culturing the bacteria for the cellulose, we added the graphene oxide flakes into the medium itself,” said Qisheng Jiang, lead author of the paper and a graduate student in the Singamaneni lab.
“The graphene oxide becomes embedded as the bacteria produces the cellulose. At a certain point along the process, we stop, remove the medium with the graphene oxide and reintroduce fresh medium. That produces the next layer of our foam. The interface is very strong; mechanically, it is quite robust.”
The new biofoam is also extremely light and inexpensive to make, making it a viable tool for water purification and desalination.
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“Cellulose can be produced on a massive scale,” Singamaneni said, “and graphene oxide is extremely cheap — people can produce tons, truly tons, of it. Both materials going into this are highly scalable. So one can imagine making huge sheets of the biofoam.”
“The properties of this foam material that we synthesized has characteristics that enhances solar energy harvesting. Thus, it is more effective in cleaning up water,” said Pratim Biswas, the Lucy and Stanley Lopata Professor and chair of the Department of Energy, Environmental and Chemical Engineering.
“The synthesis process also allows addition of other nanostructured materials to the foam that will increase the rate of destruction of the bacteria and other contaminants, and make it safe to drink. We will also explore other applications for these novel structures.”
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August 17th, 2016
By Alton Parrish.
Scientists in their preliminary findings suggest signs of life from under Mars’ surface may not survive in rocks excavated by some meteorite impacts.
Scientists analysing samples from Mars’ surface have so far not conclusively detected organic compounds that are indigenous to Mars, which would be indicators of past or present life. The inconclusive results mean that researchers are now suggesting that a good place to find these organic compounds would be deep underground – from rocks that have been blasted to the surface by meteor impacts. This is because such rocks have been sheltered from the Sun’s harmful radiation and from chemical processes on the surface that would degrade organic remains
Now, a team of scientists from Imperial College London and the University of Edinburgh has replicated meteorite blasts in the lab. The aim of the study was to see if organic compounds encased in rock could survive the extreme conditions associated with them being blasted to the surface of Mars by meteorites. The study, published today in Scientific Reports, suggests that rocks excavated through meteorite impacts may incorrectly suggest a lifeless early Mars, even if indicators of life were originally present.
In the study the team replicated blast impacts of meteorites of around 10 metres in size. The researchers found that the types of organic compounds found in microbial and algal life – long chain hydrocarbon-dominated matter- were destroyed by the pressures of impact. However, the types of organic compounds found in plant matter – dominated by aromatic hydrocarbons – underwent some chemical changes, but remained relatively resistant to impact pressures. Meteorites often contain organic matter not created by life, which have some similarities in their organic chemistry to land plants. The team infer that they also should also be resistant to blast impacts.
Their study could help future missions to Mars determine the best locations and types of blast excavated rocks to examine to find signs of life. For example, it may be that meteorite impacts of a certain size may not destroy organic compounds or scientists may need to concentrate on rocks excavated from a certain depth.
Professor Mark Sephton, co-author of the research from theDepartment of Earth Science and Engineering at Imperial College London, said: “We’ve literally only scratched the surface of Mars in our search for life, but so far the results have been inconclusive. Rocks excavated through meteorite impacts provide scientists with another unique opportunity to explore for signs of life, without having to resort to complicated drilling missions. Our study is showing us is that we may need to be nuanced in our approach to the rocks we choose to analyse.”
Dr Wren Montgomery, co-author of the study from the Department of Earth Science and Engineering, added: “The study is helping us to see that when organic matter is observed on Mars, no matter where, it must be considered whether the sample could have been affected by the pressures associated with blast impacts. We still need to do more work to understand what factors may play an important role in protecting organic compounds from these blast impacts. However, we think some of the factors may include the depths at which the rock records are buried and the angles at which meteorites hit the Martian surface.”
Meteorite impacts can eject huge quantities of rock from underground, making them an important target for searching for signs of life.
Previous in situ analyses of the Martian terrain have found inconclusive evidence for the existence organic compounds – so far only finding chlorinated organic matter. The issue for scientists has been that it is not easy to look at simple chlorine-containing organic molecules and determine the origin of the organic compound components.
NASA’s Viking landers in 1976 detected chlorine-containing organic compounds, but they were thought to be chemical left-overs from cleaning procedures of Viking’s equipment before it left Earth. Later, the Phoenix Mission in 2008 discovered chlorine-containing minerals on the Martian surface, but no organic compounds. In 2012 the Mars Science Laboratory Mission detected chlorinated organic matter, but they thought that the analysis process, which involved heating chlorine containing minerals and carbonaceous material together, was producing chlorine-containing organic compounds. Working out whether the source of the carbon found on Mars was carried once again from Earth or was indigenous to Mars remains frustratingly difficult for scientists.
The team carried out their research by subjecting the different types of organic matter to extreme pressure and temperature in a piston cylinder device. They then did a chemical analysis using pyrolysis-gas chromatography mass spectrometry.
The next steps will see the team investigating a broader range of pressures and temperatures, which would help them understand the likely effects of a greater range of meteorite impacts. This would enable them to identify the specific conditions under which organic material may escape the destructive effects of blasts – even when excavated from deep underground by violent events. This could help future Mars missions further refine the types and locations of rocks that they can analyse for signs of past or present life.
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August 16th, 2016
By Alton Parrish.
To bake quality bread, one of the key ingredients is moisture. Researchers have developed innovative ultrasonic humidification technology where moisture is produced thanks to ultrasound.
Flour, yeast, water and salt. If the recipe is simple, the process is more complex than it seems, especially in the key stage of fermentation. Once shaped, the dough rises in rooms where temperature and humidity are closely controlled.
In Nantes, a semi-industrial bakery is testing an innovative technology where moisture is produced thanks to ultrasound.
Pascal Gouvrion, managing director, Boulangerie Patisserie Associés explained: In the controlled fermentation chamber you can see this “nano” mist which is distributed throughout the room’s atmosphere. We’re able to generate high humidity, sufficient, in the order of 80%, in an atmosphere that is pretty cool because our process is precisely based on a low temperature fermentation.”
“There not an excessive moisture on the product. It can be tested by touching it, which is a standard test in bakers. We see something that is not dry, nor too wet, which is really what we are looking into in this fermentation phase.”
In Germany, the Bremerhaven’s ttz Institute was actively involved in this European research project. The ultrasonic humidification system was developed to meet the needs of bakers. Its goal: to optimize dough fermentation while saving energy.
Florian Stukenborg is head of research and development at ttz Bremerhaven: “Here we have a climate chamber, with this aerosol we can moisten products. This aerosol is produced by a mechanical process. These are mechanical vibrations. And from the surface of water, extremely fine water droplets are expelled.”
“These are mixed with air, thereby producing what we call aerosol. The difference with a conventional room is that the conventional rooms work with steam. This means that you have to convert water from a liquid phase into a gaseous phase. And this requires a lot of energy,” added Stukenborg.
Bread volume, crispy crust, soft crumb, all these parameters are analyzed thoroughly. Among the benefits of this technology, avoiding condensation and also drying of the dough (during fermentation) that can affect the quality of bread after baking.
“In conventional fermentation rooms, the air humidity is lower (inside the room), and therefore the dough, which contains high humidity, tends to release moisture. This results in what is called a skin formation, said Sonja Guttman, NanoBAK2 project manager, at ttz Bremerhaven. “In a fermentation chamber humidified with ultrasound, we have a high humidity, which is substantially identical to that of the dough, so there is no dryness at the surface of the dough.”
Apart from fermentation, the technology is also effective in the bread cooling phase. In the end, the bakers have to better control the humidity whatever the temperature and the outdoor climate. Once the bread is baked, the difference is felt.
“The main advantage is not necessarily what we expected, namely the gain in terms of energy consumption, certainly there is a gain, but it is more a gain in terms of quality and especially a consistent quality,” said Gouvrion. “It allows us to have, regardless of the weather outside, always optimal quality fermentation and crust quality, with a crispness you see, we hear “the bread singing” as bakers say.”
Ultrasound to make “bread sing”, a future promise to both industrial and artisanal bakeries.
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August 16th, 2016
By Alton Parrish.
Like cosmic ballet dancers, the stars of the Pleiades cluster are spinning. But these celestial dancers are all twirling at different speeds. Astronomers have long wondered what determines the rotation rates of these stars.
By watching these stellar dancers, NASA’s Kepler space telescope during its K2 mission has helped amass the most complete catalog of rotation periods for stars in a cluster. This information can help astronomers gain insight into where and how planets form around these stars, and how such stars evolve.
This image shows the Pleiades cluster of stars as seen through the eyes of WISE, or NASA’s Wide-field Infrared Survey Explorer.
“We hope that by comparing our results to other star clusters, we will learn more about the relationship between a star’s mass, its age, and even the history of its solar system,” said Luisa Rebull, a research scientist at the Infrared Processing and Analysis Center at Caltech in Pasadena, California. She is the lead author of two new papers and a co-author on a third paper about these findings, all being published in the Astronomical Journal.
The Pleiades star cluster is one of the closest and most easily seen star clusters, residing just 445 light-years away from Earth, on average. At about 125 million years old, these stars — known individually as Pleiads — have reached stellar “young adulthood.” In this stage of their lives, the stars are likely spinning the fastest they ever will.
As a typical star moves further along into adulthood, it loses some zip due to the copious emission of charged particles known as a stellar wind (in our solar system, we call this the solar wind). The charged particles are carried along the star’s magnetic fields, which overall exerts a braking effect on the rotation rate of the star.
Rebull and colleagues sought to delve deeper into these dynamics of stellar spin with Kepler. Given its field of view on the sky, Kepler observed approximately 1,000 stellar members of the Pleiades over the course of 72 days. The telescope measured the rotation rates of more than 750 stars in the Pleiades, including about 500 of the lowest-mass, tiniest, and dimmest cluster members, whose rotations could not previously be detected from ground-based instruments.
Kepler measurements of starlight infer the spin rate of a star by picking up small changes in its brightness. These changes result from “starspots” which, like the more-familiar sunspots on our sun, form when magnetic field concentrations prevent the normal release of energy at a star’s surface. The affected regions become cooler than their surroundings and appear dark in comparison.
As stars rotate, their starspots come in and out of Kepler’s view, offering a way to determine spin rate. Unlike the tiny, sunspot blemishes on our middle-aged sun, starspots can be gargantuan in stars as young as those in the Pleiades because stellar youth is associated with greater turbulence and magnetic activity. These starspots trigger larger brightness decreases, and make spin rate measurements easier to obtain.
During its observations of the Pleiades, a clear pattern emerged in the data: More massive stars tended to rotate slowly, while less massive stars tended to rotate rapidly. The big-and-slow stars’ periods ranged from one to as many as 11 Earth-days. Many low-mass stars, however, took less than a day to complete a pirouette. (For comparison, our sedate sun revolves fully just once every 26 days.) The population of slow-rotating stars includes some ranging from a bit larger, hotter and more massive than our sun, down to other stars that are somewhat smaller, cooler and less massive. On the far end, the fast-rotating, fleet-footed, lowest-mass stars possess as little as a tenth of our sun’s mass.
“In the ‘ballet’ of the Pleiades, we see that slow rotators tend to be more massive, whereas the fastest rotators tend to be very light stars,” said Rebull.
The Pleiades
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The main source of these differing spin rates is the internal structure of the stars, Rebull and colleagues suggest. Larger stars have a huge core enveloped in a thin layer of stellar material undergoing a process called convection, familiar to us from the circular motion of boiling water. Small stars, on the other hand, consist almost entirely of convective, roiling regions. As stars mature, the braking mechanism from magnetic fields more easily slows the spin rate of the thin, outermost layer of big stars than the comparatively thick, turbulent bulk of small stars.
Thanks to the Pleiades’ proximity, researchers think it should be possible to untangle the complex relationships between stars’ spin rates and other stellar properties. Those stellar properties, in turn, can influence the climates and habitability of a star’s hosted exoplanets. For instance, as spinning slows, so too does starspot generation, and the solar storms associated with starspots. Fewer solar storms means less intense, harmful radiation blasting into space and irradiating nearby planets and their potentially emerging biospheres.
“The Pleiades star cluster provides an anchor for theoretical models of stellar rotation going both directions, younger and older,” said Rebull. “We still have a lot we want to learn about how, when and why stars slow their spin rates and hang up their ‘dance shoes,’ so to speak.”
Rebull and colleagues are now analyzing K2 mission data from an older star cluster, Praesepe, popularly known as the Beehive Cluster, to further explore this phenomenon in stellar structure and evolution.
“We’re really excited that K2 data of star clusters, such as the Pleiades, have provided astronomers with a bounty of new information and helped advance our knowledge of how stars rotate throughout their lives,” said Steve Howell, project scientist for the K2 mission at NASA’s Ames Research Center in Moffett Field, California.
The K2 mission’s approach to studying stars employs the Kepler spacecraft’s ability to precisely observe miniscule changes in starlight. Kepler’s primary mission ended in 2013, but more exoplanet and astrophysics observations continue with the K2 mission, which began in 2014.
Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.
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July 2nd, 2016
By Alton Parrish.
Human use of artificial light is causing Spring to come at least a week early in the UK, researchers at the University of Exeter in Cornwall have found.
New research led by a team of biologists based at the University’s Penryn campus highlights for the first time and at a national scale the relationship between the amount of artificial night-time light and the date of budburst in woodland trees.
Researchers believe early bud bursting will have a cascade effect on other organisms.
The study, the result of a long term collaboration with independent environmental consultants Spalding Associates, in Truro, made use of data collected by citizen scientists from across the UK, after the Woodland Trust asked them to note down when they first saw sycamore, oak, ash and beech trees in leaf as part of the charity’s Nature’s Calendar initiative. The research team analysed this, information, correlated with satellite images of artificial lighting.
The research, published in the journal Proceedings of the Royal Society B, found that buds were bursting by up to 7.5 days earlier in brighter areas and that the effect was larger in later budding trees.
Researchers believe early bud bursting will have a cascade effect on other organisms whose life cycles work in synchronicity with the trees. The proliferation of the winter moth for example, which feeds on fresh emerging oak leaves is likely to be affected which may in turn have some effect on birds in the food chain that rely on it for food.
The findings provide important information for those in charge of lighting levels, such as local councils, and point to the need for further research into the impact of different light quality and the specific wavelengths of light generated by different lighting types.
“Our finding that the timing of bud burst of woodland tree species may be affected by light pollution suggests that smaller plants growing below the height of street lights are even more likely to be affected,” said Professor Richard ffrench-Constant of the department of the department of Biosciences based at the University’s Penryn campus. “Such results highlight the need to carry out experimental investigation into the impact of artificial night-time lighting on phenology and species interactions.”
Behavioural ecologist Peter McGregor, of the Centre for Applied Zoology at Cornwall College Newquay, said: “This study also shows that we can use citizen science in a meaningful way and that it has a real role to play in research that can have a meaningful impact.”
Adrian Spalding of Spalding Associates in Truro is one of the leading experts on moths in Britain He believes this work is important as councils have recently been given control over decisions as to when they want to turn on or off their street lights.
“This study shows the importance of collaborative research between business and academia to address our real concerns of the effect of lighting on plants and animals and the importance of managing light levels in our urban environment in a sustainable way.”
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July 2nd, 2016
By Alton Parrish.
Astronomers are using the NASA/ESA Hubble Space Telescope to study auroras — stunning light shows in a planet’s atmosphere — on the poles of the largest planet in the Solar System, Jupiter. This observation programme is supported by measurements made by NASA’s Juno spacecraft, currently on its way to Jupiter.
Jupiter, the largest planet in the Solar System, is best known for its colorful storms, the most famous being the Great Red Spot. Now astronomers have focused on another beautiful feature of the planet, using the ultraviolet capabilities of the NASA/ESA Hubble Space Telescope.
The extraordinary vivid glows shown in the new observations are known as auroras . They are created when high energy particles enter a planet’s atmosphere near its magnetic poles and collide with atoms of gas. As well as producing beautiful images, this programme aims to determine how various components of Jupiter’s auroras respond to different conditions in the solar wind, a stream of charged particles ejected from the Sun.
Jupiter’s auroras were first discovered by the Voyager 1 spacecraft in 1979. A thin ring of light on Jupiter’s nightside looked like a stretched-out version of our own auroras on Earth. Only later on was it discovered that the auroras were best visible in the ultraviolet.
This image combines an image taken with Hubble Space Telescope in the optical (taken in spring 2014) and observations of its auroras in the ultraviolet, taken in 2016.
This observation programme is perfectly timed as NASA’s Juno spacecraft is currently in the solar wind near Jupiter and will enter the orbit of the planet in early July 2016. While Hubble is observing and measuring the auroras on Jupiter, Juno is measuring the properties of the solar wind itself; a perfect collaboration between a telescope and a space probe.
This is not the first time astronomers have used Hubble to observe the auroras on Jupiter, nor is it the first time that Hubble has cooperated with space probes to do so. In 2000 the NASA/ESA/ASI Cassini spacecraft made its closest approach to Jupiter and scientists used this opportunity to gather data and images about the auroras simultaneously from Cassini and Hubble (heic0009). In 2007 Hubble obtained images in support of its sister NASA Mission New Horizons which used Jupiter’s gravity for a manoeuvre on its way to Pluto (opo0714a).
“These auroras are very dramatic and among the most active I have ever seen”, says Jonathan Nichols from the University of Leicester, UK, and principal investigator of the study. “It almost seems as if Jupiter is throwing a firework party for the imminent arrival of Juno.”
To highlight changes in the auroras Hubble is observing Jupiter daily for around one month. Using this series of images it is possible for scientists to create videos that demonstrate the movement of the vivid auroras, which cover areas bigger than the Earth.
Not only are the auroras huge, they are also hundreds of times more energetic than auroras on Earth. And, unlike those on Earth, they never cease. Whilst on Earth the most intense auroras are caused by solar storms — when charged particles rain down on the upper atmosphere, excite gases, and cause them to glow red, green and purple — Jupiter has an additional source for its auroras.
This timelapse video of the vivid auroras in Jupiter’s atmosphere was created using observations made with the NASA/ESA Hubble Space Telescope. Hubble is particularly suited to observing and studying the auroras on the biggest planet in the Solar System, as they are brightest in the ultraviolet
The strong magnetic field of the gas giant grabs charged particles from its surroundings. This includes not only the charged particles within the solar wind but also the particles thrown into space by its orbiting moon Io, known for its numerous and large volcanoes.
This timelapse video of the vivid auroras in Jupiter’s atmosphere was created using observations made with the NASA/ESA Hubble Space Telescope. Hubble is particularly suited to observing and studying the auroras on the biggest planet in the Solar System, as they are brightest in the ultraviolet.
The new observations and measurements made with Hubble and Juno will help to better understand how the Sun and other sources influence auroras. While the observations with Hubble are still ongoing and the analysis of the data will take several more months, the first images and videos are already available and show the auroras on Jupiter’s north pole in their full beauty.
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July 1st, 2016
By Alton Parrish.
In the lead up to the World Barista Championships, University of Bath scientists say brewing more flavorsome coffee could be as simple as chilling the beans before grinding.
A team from the University working with renowned Bath coffee shop Colonna & Smalls found that chilling roasted beans before grinding resulted in narrower distribution of small particles, which during the brewing process allows access to more flavor from the same amount of coffee.
That’s important because small uniform coffee grinds allow for better extraction of the flavor compounds – allowing you to brew more coffee and get more flavor. So it is important to buy good quality french press amazon to get the best coffee.
Coffee is among the most valuable traded commodities globally, the U.S. coffee market is estimated to be $48 billion in 2015 alone. This discovery could have big implications for the coffee industry and might even allow domestic coffee connoisseurs to brew tastier beverages.
Maxwell Colonna-Dashwood (L) and Dr Christopher Hendon (R) at the Colonna & Smalls coffee shop in Bath
The team studied the effect of grinding beans at different temperatures, from room temperature to -196°C, and discovered that the colder the beans the finer and more uniform the particles were from the grind.
That’s important, because small uniform coffee grinds allow for better extraction of the flavor compounds – allowing you to brew more coffee and get more flavor.
Dr Christopher Hendon, a chemistry PhD student at the University of Bath at the time of the study, now working at the Massachusetts Institute of Technology, said: “What you’re looking for is a grind that has the smallest difference between the smallest and largest particle. If you have small grinds you can push flavor extraction upwards. We found that chilling the beans tightens up this process and can give higher extractions with less variance in the flavor – so you would have to brew it for less time, or could get more coffee from the same beans.
“It will alter the taste, because subtle changes in particle size distributions make a huge difference in rate of extraction. I wouldn’t be surprised if people struggled to achieve balanced extractions.
“It could have a major impact for the industry. People are trying to produce a very high quality drink with really quite powerful tools and are willing to try new things.”
The study, highlighted in Nature, is published in Scientific Reports.
Maxwell Colonna-Dashwood, co-owner of Colonna & Smalls, said: “Grinding coffee may seem quite straightforward – break coffee up into a lot of tiny bits so you can dissolve it in water. But like the whole world of coffee the subtleties of the process have a huge impact on the flavor and quality of the cup of coffee. The ability to understand grinding more comprehensively has the dual impact of allowing us to make better tasting coffee and to be more efficient in the way we do that.
“The research suggests that temperature of bean needs to be more constant to help us achieve consistent grinds. It suggests that cooler temperatures will allow us to maximize surface area and utilise more of the coffee. All of this will impact on how we prepare coffee in the industry, I bet we will see the impact of this paper in coffee competitions around the globe, but also in the research and development of new grinding technology for the market place.”
The World Barista Championships took place in Dublin between 22-25 June.
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July 1st, 2016
By Alton Parrish.
Consumers know some of the benefits blueberries provide, but they’re less aware of the advantages of reverting aging, improving vision and memory, a new University of Florida study shows.
Shuyang Qu, a doctoral student in agricultural education and communication at the University of Florida Institute of Food and Agricultural Sciences, led the study.
Joining Qu were Joy Rumble, a UF/IFAS assistant professor of agricultural education and communication, and Tori Bradley, a master’s student in the UF/IFAS food and resource economics department. Rumble’s Florida Specialty Crop grant gave the opportunity to examine consumers’ knowledge of blueberry health benefits.
Qu and her colleagues wanted to determine how much consumers know about blueberry health benefits and see if there’s a knowledge gap with blueberry health benefits among demographic groups. Using their findings, they will identify promotional opportunities for Florida blueberries.
Researchers surveyed more than 2,000 people in 31 states – mostly on the East Coast and in the Midwest – to see what they know about the health benefits of blueberries. Most were aware of the benefits of blueberries in warding off cancer and lowering the risk of heart disease. The UF/IFAS study also found that low-income populations tend to know less about blueberry health benefits.
“People being more familiar with blueberries as deterrents for cancer and heart disease may be related to the high general awareness of these two diseases,” Qu said. “The fact that cancer and heart diseases are the leading causes of death in America may have led to more personal research related to preventing the diseases, leading to the respondents being exposed to these findings more than other benefits.”
To help promote blueberries’ health benefits, Qu and her colleagues suggest holding events during blueberry season, such as tastings or u-picks to draw consumers to the crop while providing a vehicle for information about blueberry health benefits.
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June 30th, 2016
By Alton Parrish.
National Oceanography Centre scientists have discovered the Caribbean Sea works like a whistle.
This finding will enable scientists to predict some sea level changes many months in advance, and may be an important factor in regulating how the Gulf Stream varies.
This research, published today in Geophysical Research Letters, has found the Caribbean Current flow is unstable, which causes it to shed eddies, or swirling currents of water hundreds of kilometres in diameter. This is similar to the way in which a jet of air sheds eddies when it hits the lip of a whistle.
Rossby waves are planetary waves that determine basic meteorological conditions at latitudes outside of the tropics.
Vorticity is generated in the atmospheric and ocean fluids by the rotation of the earth since these fluids can’t co-rotate with the earth because of internal currents and friction and various energy losses. Vorticity is a measure of spin.
In a whistle the radiating sound comes from a resonating pressure wave created by the eddies, causing mass to be exchanged with the air around it. In the case of the current the eddies create a resonant Rossby wave in the ocean basin, which because it is not completely closed, allows water mass to be exchanged with the rest of the ocean. The net result is a sloshing of water into and out of the basin with a period of 120 days, corresponding to a note of A flat, many octaves below the audible range.
The sloshing water is big enough to be detected by its gravitational influence on the GRACE satellites.
Caribbean
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Furthermore, the Rossby wave resonance relies on a peculiar effect known as a Rossby wormhole – the wave propagates to the west across the basin where it seems to disappear, only to reappear in the east Advanced computer models of the ocean, run at the NOC, predicted this should happen. This prediction was later confirmed using a range of observations, including satellite gravity, satellite sea level measurements, coastal tide gauges and a bottom pressure recorder which is part of the global tsunami warning network.
Professor Chris Hughes, who led the research, said “It was a real surprise to find this oscillation. We were looking at ocean bottom pressure data from round the world as part of an NOC contribution to the global sea level database, which we host, and found this region. It behaved quite differently from the rest of the tropics, which are typically very quiet. With hindsight we found theoreticians had predicted this kind of behaviour, but had never thought to apply their models to the Caribbean Sea – ironically this seems to be the only place where conditions are suitable.”The oscillation is always present, sometimes with higher and sometimes with lower amplitude. Since the waves van be seen as they propagate across the Caribbean Sea, scientists can predict when the wave will arrive at the coast and cause the sea level to rise or fall at least 120 days in advance.
The work was funded by the Natural Environment Research Council (NERC) as part of a project on Weighing the Ocean and forms part of the NOC’s ongoing research into global ocean dynamics and sea level.
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June 30th, 2016
By Alton Parrish.
Hazes and clouds high up in the atmospheres of exoplanets may make them appear bigger than they really are, according to new research by astronomers at the Space Research Institute (IWF) of the Austrian Academy of Sciences. The team, led by researcher Dr Helmut Lammer, publish their results in a letter to Monthly Notices of the Royal Astronomical Society.
An artist’s illustration of a hot Neptune-sized world moving behind its host star.
Since the first confirmed discovery in 1993, astronomers have found more than 3,000 planets in orbit around stars other than our Sun. A key goal now is to characterise known worlds by mass, size and composition, to better understand the evolution of planetary systems, and the prospects for ‘Earthlike’ planets that might support life.
In 2014 Lammer and his team used the European Space Agency (ESA) CoRoT space telescope to study the upper atmosphere of two low-mass planets that are regularly seen to pass in front of (transit) the star they orbit. The two planets orbit their star in 5 and 12 days, appear to be around 4 and 5 times the diameter of the Earth, and have respective masses of less than 6, and 28 times Earth. The outer, more massive planet, CoRoT-24c, is similar in mass to Neptune. In contrast, the inner planet, CoRoT-24b, is less than a quarter as massive, but is similar in size, so seems to have a very low density.
With such short orbits, both worlds are close to and will experience dramatic heating from the star. The team modelled this and found that the lower mass planet would see its atmosphere evaporate within 100 million years, if it really is as big as suggested. But the star is billions of years old, so the planet should have lost its atmosphere long ago.
A diagram of a the hot low-mass extended atmosphere with cloud deck and haze, around the exoplanet CoRoT-24b (left), compared to the cooler, more massive, and compact CoRoT-24c (right).
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The solution seems to be that the planet is only about half as big as thought. Lammer argues that an extended, very thin, atmosphere, surrounds a relatively compact planet, but has high altitude features that confuse observations. He explains: “The radius is based on what we see when the planet makes its transit. This is probably distorted by clouds and haze high in the atmosphere, in a region where atmospheric pressure is otherwise very low.”
Co-author Luca Fosseti adds that this effect needs to be considered by future exoplanet missions, like the ESA CHaracterising ExOPlanets Satellite (CHEOPS) mission due to launch in December 2017. Results for some worlds found by the NASA Keplerobservatory may also need to be re-evaluated.
“Our results show that CHEOPS scientists need to be cautious about their first measurements”, says Fossati.
“Since Kepler has also discovered several similar low-density and low-mass planets, it is very likely that the size measured for many of them also differ from the true value, so there could be a bias in the results.”
If the Austrian team are right, this has dramatic implications, for example in the studies of planet populations and how the mass of planets relate to their size.
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June 29th, 2016
By Alton Parrish.
The media often imply that the goal of the hunt for extrasolar planets is to find a rocky planet about the size of Earth orbiting a star like the sun at a distance that would allow liquid water to persist on its surface. In other words, the goal is to find Earth 2.0. Hot, rocky planets may change their composition if rock components vaporize in steam atmospheres that escape to space.
But there are reasons to be interested in the other worlds even if they couldn’t possibly harbor life. The hot, rocky planets, for example, offer rare and precious clues to the character and evolution of the early Earth.
The Kepler satellite has detected more than 100 hot, rocky planets orbiting close to their stars. If these planets formed from interstellar clouds with Earth-like abundances of volatile elements, like hydrogen, water and carbon dioxide, these planets might have steam atmospheres.
Washington University in St. Louis cosmochemists show that hot, rocky exoplanets with steam atmospheres may vaporize some of their rocky elements and then lose them to space, changing the bulk composition of the planet.
Steaming a rocky planet wouldn’t just press out the wrinkles. Because the rock-forming elements dissolve in steam to different extents, steaming could, in principle, alter the planet’s bulk composition, density and internal structure, especially if all or part of the rock-bearing steam atmosphere was then lost to space.
Bruce Fegley and Katharina Lodders-Fegley, respectively professor and research professor in earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, published models of the chemistry of a steam atmosphere in equilibrium with a magma ocean at various temperatures and pressures in the June 20, 2016 issue of the Astrophysical Journal.
Based on their findings, they have some suggestions for planet hunters — things they might see when they train their telescopes on the hot rocks.
Getting some steam up
The fact that planet hunters have discovered many hot rocks roughly the size of Earth is one of three lines of evidence that come together in this research, Fegley said. The other two are the solubility of silica and other rock-forming elements in steam, and the idea that the early Earth had a steam atmosphere.
The notion that rocks will dissolve in steam may seem outlandish, but it is common knowledge among geologists. “Geologists are mainly concerned with very hot water or water and steam mixtures, whereas we’re looking at pure steam and temperatures hundreds of degrees hotter. But it’s the same kind of idea,” Fegley said.
The suspicion that the early Earth had a steam atmosphere goes back to 1974, when Gustave Arrhenius of the Scripps Institute of Oceanography argued that planetesimals that smacked into the forming Earth got hot enough to melt and release all their volatiles into the atmosphere.
The first to model the steam atmosphere of the early Earth were Yutaka Abe and Takafumi Matsui of the University of Tokyo in 1985. “They were mainly interested in the physics of the problem,” Fegley said, “and whether greenhouse gases acting as a thermal blanket would keep the surface molten. I think we’re the first ones to do a detailed chemistry on it.”
Escaping steam
Fegley and Lodders looked particularly at magnesium, silicon and iron, the three most abundant elements in material that combine with oxygen to form rock — both on Earth and the other terrestrial planets and probably on exoplanets orbiting stars with a composition like our sun’s.
The rocky elements enter the atmosphere as hydroxides (Si(OH)4, Fe(OH)2, and Mg (OH)2). Because these oxides have different solubilities in steam, cooking a planet in steam can change its major-element chemistry.
“Potassium, for example, easily goes into steam and if it’s lost, you’ll lose its radioactive isotope and so change the heat production on the planet,” Fegley said.
“If you dissolve more silicon than magnesium, and some of the atmosphere is lost, you can change the ratio of these elements in the planets. This might explain why the ratio of silicon to magnesium in the Earth is about 15 percent smaller than the ratio in the sun, even though the two formed from the same interstellar cloud,” he said.
“If you boil off a lot of the silicon, you might end up with a much denser planet than you’d expect. We’ve found some pretty dense exoplanets,” Fegley said. “Sometimes it’s crazy high. Earth is about 5.51 g/cm3, but Corot-7b is closer to 10 g/cm3 . . . high enough that it’s kind of hard to explain.
“And if you don’t lose the atmosphere, when the atmosphere cools down, the rock-forming elements would precipitate out. Since silicon is the rocky element most soluble in steam, it will be the most abundant, and you’ll get a silicate-rich-crust ready-made,” he said.
What to look for
Although the scientists are experimenting with numerical models, they remark that their conclusions are testable by observation.
“We’re hoping astrophysicists doing mass/radius diagrams to figure out the internal composition of planets will consider compositions other than Earth’s,” Fegley said.
“We’re also hoping space-based spectrometers will be trained on the hot, rocky planets. Astrophysicists see silicon, magnesium and sodium coming off the atmospheres of hot Jupiters and hot Neptunes but not yet off of hot rocks, which are dimmer and harder to observe,” Fegley said.
Intense ultraviolet light from nearby stars is likely to break up hydroxide molecules at the top of atmospheres, the scientists said. The “photoproducts” of these reactions, such as monatomic gases of aluminum, calcium, iron, magnesium and silicon, might be easier to see both because of their abundances and because their spectral lines are less likely be masked by other emissions.
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June 29th, 2016
By Alton Parrish.
The Universe is becoming gradually cleaner as more and more cosmic dust is being mopped up by the formation of stars within galaxies, an international team of astronomers has revealed.
Peering back 12 billion years using the Herschel space telescope to produce far-infrared images of the sky, the team led by researchers at Cardiff University has been able to observe the very early formation of galaxies and compare them to galaxies that have formed much more recently.
The results showed that stars were forming inside galaxies much faster in the past compared to today, and that this rapid star birth is using up more and more of the cosmic dust that is ubiquitous in the Universe.
Cosmic dust is comprised of tiny solid particles that are found everywhere in space between the stars. The dust and the gas in the universe is the raw material out of which stars and galaxies form.
A small glimpse of one region, a tenth of the full area of the Herschel ATLAS images. Everything in this image, apart from the picture of the moon, which has just been placed there to show the area of sky covered by the survey and the small square that shows the area covered by the Hubble Deep Field, consists of far-infrared emission from cosmic dust.
Though this blanket of material is key to the formation of stars and galaxies, it also acts as a sponge, absorbing almost half of the light emitted by stellar objects and making them impossible to observe with standard optical telescopes.
With the launch of the Herschel space telescope in 2009, researchers were provided with the perfect tool for probing this hidden universe. Owing to a collection of sensitive instruments, mirrors and filters, the Herschel telescope had the capacity to detect the dust through the far-infrared emission it emits, revealing the existence of stars and galaxies hidden by the dust.
Professor Steve Eales, a co-leader of the project from Cardiff University’s School of Physics and Astronomy, said: “We were surprised to find that we didn’t need to look far in the past to see signs of galaxy evolution. Our results show that the reason for this evolution is that galaxies used to contain more dust and gas in the past, and the universe is gradually becoming cleaner as the dust is used up.”
Professor Haley Gomez, also of the School of Physics and Astronomy, presented the team’s results today, 29 June, at the National Astronomy Meeting in Nottingham. After seven years of work analysing the images from the Herschel telescope, the team of over 100 astronomers have released a large catalogue of the sources of far-infrared radiation in this ‘hidden universe’.
The team’s survey of the sky, called the Herschel Astrophysical Terahertz Large Area Survey (Herschel ATLAS), has revealed the details of over half a million galaxies, many of which have been viewed as they were over 12 billion years ago, just shortly after the big bang.
The team are hopeful that this unprecedented catalogue of sources will be vital tools for astronomers wishing to understand the detailed history of galaxies and the wider cosmos.
Dr Elisabetta Valiante, a lead author from Cardiff University’s School of Physics and Astronomy, said: “The exciting thing about our survey is that it encompasses almost all of cosmic history, from the violent star-forming systems full of dust and gas in the early universe, that are essentially galaxies in the process of formation, to the much more subdued systems we see around us today.”
Dr Loretta Dunne, a co-leader of project from Cardiff University’s School of Physics and Astronomy, said: “Before Herschel we only knew of a few hundred such dusty sources in the distant universe and we could only effectively ‘see’ them in black and white. Herschel, with its five filters, has given us the equivalent of technicolour, and the colour of the galaxy tell us about their distances and temperatures. So we now have half a million galaxies we can use to map out the hidden star formation in the universe.”
The project was jointly funded by the Science and Technology Facilities Council, the European Union’s 7th Framework Programme for Research and Technological Development, and the European Research Council.
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June 28th, 2016
By Alton Parrish.
If you leave a cube of Jell-O on the kitchen counter, eventually its water will evaporate, leaving behind a shrunken, hardened mass — hardly an appetizing confection. The same is true for hydrogels. Made mostly of water, these gelatin-like polymer materials are stretchy and absorbent until they inevitably dry out.
Now engineers at MIT have found a way to prevent hydrogels from dehydrating, with a technique that could lead to longer-lasting contact lenses, stretchy microfluidic devices, flexible bioelectronics, and even artificial skin.
See how MIT researchers designed a hydrogel that doesn’t dry out.
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The engineers, led by Xuanhe Zhao, the Robert N. Noyce Career Development Associate Professor in MIT’s Department of Mechanical Engineering, devised a method to robustly bind hydrogels to elastomers — elastic polymers such as rubber and silicone that are stretchy like hydrogels yet impervious to water. They found that coating hydrogels with a thin elastomer layer provided a water-trapping barrier that kept the hydrogel moist, flexible, and robust. The results are published today in the journal Nature Communications.
Zhao says the group took inspiration for its design from human skin, which is composed of an outer epidermis layer bonded to an underlying dermis layer. The epidermis acts as a shield, protecting the dermis and its network of nerves and capillaries, as well as the rest of the body’s muscles and organs, from drying out.
Engineers at MIT have devised a method to bind two stretchy materials: gelatin-like polymer materials called hydrogels, and elastomers, which are impervious to water and can thus seal in the hydrogel’s water.
The team’s hydrogel-elastomer hybrid is similar in design to, and in fact multiple times tougher than, the bond between the epidermis and dermis. The team developed a physical model to quantitatively guide the design of various hydrogel-elastomer bonds. In addition, the researchers are exploring various applications for the hybrid material, including artificial skin. In the same paper, they report inventing a technique to pattern tiny channels into the hybrid material, similar to blood vessels. They have also embedded complex ionic circuits in the material to mimic nerve networks.
“We hope this work will pave the way to synthetic skin, or even robots with very soft, flexible skin with biological functions,” Zhao says.
The paper’s lead author is MIT graduate student Hyunwoo Yuk. Co-authors include MIT graduate students German Alberto Parada and Xinyue Liu and former Zhao group postdoc Teng Zhang, now an assistant professor at Syracuse University.
Getting under the skin
In December 2015, Zhao’s team reported that they had developed a technique to achieve extremely robust bonding of hydrogels to solid surfaces such as metal, ceramic, and glass. The researchers used the technique to embed electronic sensors within hydrogels to create a “smart” bandage. They found, however, that the hydrogel would eventually dry out, losing its flexibility.
Others have tried to treat hydrogels with salt to prevent dehydration, but Zhao says this method can make a hydrogel incompatible with biological tissues, and even toxic. Instead, the researchers, inspired by skin, reasoned that coating hydrogels with a material that was similarly stretchy but also water-resistant would be a better strategy for preventing dehydration. They soon landed on elastomers as the ideal coating, though the rubbery material came with one major challenge: It was inherently resistant to bonding with hydrogels.
“Most elastomers are hydrophobic, meaning they do not like water,” Yuk says. “But hydrogels are a modified version of water. So these materials don’t like each other much and usually can’t form good adhesion.”
The team tried to bond the materials together using the technique they developed for solid surfaces, but with elastomers, Yuk says, the hydrogel bonding was “horribly weak.” After searching through the literature on chemical bonding agents, the researchers found a candidate compound that might bring hydrogels and elastomers together: benzophenone, which is activated via ultraviolet (UV) light.
Figure (a) shows the fabrication procedure for a hydrogel-elastomer microfluidic chip. Figure (b) shows that the hydrogel-elastomer microfluidic hybrid supports convection of chemicals (represented by food dye in different colors) in the microfluidic channels and diffusion of chemicals in the hydrogel, even when the material is stretched, as seen in figure (c). In figure (d), the microfluidic hybrid is used as a platform for a diffusion-reaction study. Acid and base solutions from two microfluidic channels diffuse in the pH-sensitive hydrogel and form regions of different colors (light red for acid and dark violet for base).
After dipping a thin sheet of elastomer into a solution of benzophenone, the researchers wrapped the treated elastomer around a sheet of hydrogel and exposed the hybrid to UV light. They found that after 48 hours in a dry laboratory environment, the weight of the hybrid material did not change, indicating that the hydrogel retained most of its moisture. They also measured the force required to peel the two materials apart, and found that to separate them required 1,000 joules per square meters — much higher than the force needed to peel the skin’s epidermis from the dermis.
“This is tougher even than skin,” Zhao says. “We can also stretch the material to seven times its original length, and the bond still holds.”
Expanding the hydrogel toolset
Taking the comparison with skin a step further, the team devised a method to etch tiny channels within the hydrogel-elastomer hybrid to simulate a simple network of blood vessels. They first cured a common elastomer onto a silicon wafer mold with a simple three-channel pattern, etching the pattern onto the elastomer using soft lithography. They then dipped the patterned elastomer in benzophenone, laid a sheet of hydrogel over the elastomer, and exposed both layers to ultraviolet light. In experiments, the researchers were able to flow red, blue, and green food coloring through each channel in the hybrid material.
Yuk says in the future, the hybrid-elastomer material may be used as a stretchy microfluidic bandage, to deliver drugs directly through the skin.
“We showed that we can use this as a stretchable microfluidic circuit,” Yuk says. “In the human body, things are moving, bending, and deforming. Here, we can perhaps do microfluidics and see how [the device] behaves in a moving part of the body.”
The researchers also explored the hybrid material’s potential as a complex ionic circuit. A neural network is such a circuit; nerves in the skin send ions back and forth to signal sensations such as heat and pain. Zhao says hydrogels, being mostly composed of water, are natural conductors through which ions can flow. The addition of an elastomer layer, he says, acts as an insulator, preventing ions from escaping — an essential combination for any circuit.
To make it conductive to ions, the researchers submerged the hybrid material in a concentrated solution of sodium chloride, then connected the material to an LED light. By placing electrodes at either end of the material, they were able to generate an ionic current that switched on the light.
“We show very beautiful circuits not made of metal, but of hydrogels, simulating the function of neurons,” Yuk says. “We can stretch them, and they still maintain connectivity and function.”
Syun-Hyun Yun, an associate professor at Harvard Medical School and Massachusetts General Hospital, says that hydrogels and elastomers have distinct physical and chemical properties that, when combined, may lead to new applications.
“It is a thought-provoking work,” says Yun, who was not involved in the research. “Among many [applications], I can imagine smart artificial skins that are implanted and provide a window to interact with the body for monitoring health, sensing pathogens, and delivering drugs.”
Next, the group hopes to further test the hybrid material’s potential in a number of applications, including wearable electronics and on-demand drug-delivering bandages, as well as nondrying, circuit-embedded contact lenses.
“Ultimately, we’re trying to expand the argument of using hydrogels as an advanced engineering toolset,” Zhao says.
This research was funded, in part, by the Office of Naval Research, Draper Laboratory, MIT Institute for Soldier Nanotechnologies, and National Science Foundation.
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June 28th, 2016
By Alton Parrish.
Around half of the star formation in the local Universe arises from minor mergers between galaxies, according to data from the Sloan Digital Sky Survey. The patch of sky called Stripe 82 is observed repeatedly to produce high-quality images of spiral galaxies. Disruptions to the shapes of these galaxies, caused by interactions with their smallest neighbors, pointed to increased star formation in a study being presented at the National Astronomy Meeting at the University of Nottingham.
A NASA/ESA Hubble Space Telescope view of the spiral galaxy NGC 7714, which has been dramatically distorted in shape by a close interaction with another nearby galaxy. Minor, but frequent, disturbances such as this cause a burst of star formation, accounting for around half of all new stars being formed in the local Universe.’
Gravity, the ubiquitous attractive force that pervades our Universe, is a significant driver of galaxy formation. Gravity makes galaxies collide, and these collisions can affect various properties – merging drives strong star formation in the galaxies in question, increases the masses of their constituent black holes and can significantly alter the internal structure of the galaxies.
Our classical paradigm has often assumed that mergers between equal mass progenitors (‘major’ mergers) have the most transformative impact on galaxies. However, such events are rare. Much more common are mergers between massive galaxies and small satellites (‘minor’ mergers). This is because small galaxies far outnumber their more massive counterparts – the attractive nature of gravity then ensures that these massive galaxies are constantly being bombarded by satellites.
While major mergers are more spectacular and easier to study because they tend to be brighter, studying minor mergers requires large surveys which offer ‘deep’ i.e. long exposure imaging which is able to detect the faint tidal features that are the signatures of minor mergers.
Recently, circumstantial evidence is accumulating that suggests that minor mergers are indeed important drivers of galaxy evolution e.g. the observed size growth of galaxies over the last 10-12 billion years is likely due to repeated minor mergers. This study is the first to use a deep survey to quantify what fraction of the star formation in the nearby Universe is likely to be driven by the minor-merger process. “The results are striking”, according to Dr Sugata Kaviraj of the University of Hertfordshire, the scientist behind this work. “Just over half of the cosmic star formation budget is directly driven by minor mergers. In other words, if this process did not take place then galaxies in today’s Universe would be at least a factor of two less massive.”
Without a good comprehension of the minor-merger process, therefore, our understanding of galaxy evolution will remain incomplete. This paper is a precursor to work that can be done using future instrumentation like the Large Synoptic Survey Telescope which will, for the first time, provide deep imaging over around half the sky, enabling the first statistically robust studies of minor merging over at least 50% of cosmic time.
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June 27th, 2016
By Alton Parrish.
Launch of the world’s first quantum communications satellite will take place in August, the leader of China’s space science program has said.
Dr Wu Ji of the National Space Science Centre (NSSC) under the Chinese Academy of Sciences (CAS), told reporters in Beijing while updating on space science missions (link in Chinese).
The pioneering QUantum Experiments at Space Scale (QUESS) mission, part of China’s ambitious space science agenda, was expected to launch from Jiuquan Satellite Launch Centre in July, but has now been moved to August.
Once launched on a Long March 2D rocket, the 620kg QUESS satellite will delve into the counter-intuitive quantum world, including the spooky phenomenon of quantum entanglement, and seek breakthroughs in cryptography.
It will also attempt quantum teleportation at a space scale, and fundamental tests of the laws of quantum mechanics on a global scale.
While the cause of the delay was not stated, major problems with the payload seem unlikely.
At the same time, 2016 will be China’s busiest year so far in terms of launches, with more than 20 planned, placing added strain on rocket production capabilities.
Dark matter, microgravity and beyond
QUESS is just one of four missions in the Strategic Priority Program on Space Science run by the Chinese Academy of Sciences, initiated in 2011.
Implemented by the NSSC in Beijing, two missions – the DAMPE (Wukong) Dark Matter probe in December, and April’sShijian-10 retrievable microgravity space science satellite – have already been launched.
QUESS will be followed later in the year by the fourth mission, the Hard X-ray Modulation Telescope (HXMT), which will observe black holes, neutron stars and other phenomena based on their X-ray and gamma ray emissions over a four-year lifetime.
New space science missions
With this first batch of space science missions about to bear fruit, China is working on five new probes to study a range of Earth, solar and deep space phenomena.
The missions, announced earlier this month, are the space-weather observatory mission in collaboration with the European Space Agency (SMILE), a global water cycle observation mission (WCOM), the Magnetosphere, Ionosphere and Thermosphere mission (MIT), Einstein Probe (EP), and the Advanced Space-based Solar Observatory (ASO-S).
The missions were selected from those outlined in a national roadmap for space science for 2016-2030 produced by the NSSC, and will follow on from a range of exciting Chinese space science missions in 2016.
Wu Ji, recently profiled by Nature as star of Chinese science, said each scientific satellite is pioneering and non-repetitive, meaning the missions require new ideas, new designs, new materials and technologies, and as such Chinese space science efforts are a major driving force for innovation.
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