Tech

Imagine having an electrode embedded in your brain in a surgical procedure that involves drilling holes in your skull to implant it. Now imagine going through an MRI scan for medical evaluation, when the metal electrode may react to the magnetic fields and vibrate, generate heat or even possibly damage the brain.

This is a reality that patients who need deep brain stimulation could face.

Now, a study published Nov. 18 in Nature Microsystems & Nanoengineering describes a promising improvement to the procedure developed by San Diego State University engineers, in collaboration with researchers at KIT, Germany. The SDSU research team created a glassy carbon electrode as an alternative to the metal version, and new findings show it does not react to MRI scans, making it safer.

First developed in 2017 in researcher Sam Kassegne's MEMS lab at SDSU, the carbon version is designed to last longer in the brain without getting corroded or deteriorated, and to emit and receive stronger signals. In 2018, the researchers showed that while the metal electrode degrades after 100 million cycles of electrical impulses applied to it, the glassy carbon material survived 3.5 billion cycles.

Deep brain stimulation - where electrodes implanted in the brain produce electrical impulses that control abnormal movement - is increasingly being used for those with movement disorders that don't respond to medication, such as patients with Parkinson's disease, tremors, and uncontrolled muscle contractions known as dystonia.

It's also being considered for traumatic brain injury, addiction, dementia, depression and other conditions, so the potential applications are vast.

Until now, the electrodes have been made out of thin-film platinum or iridium oxide. But such metal-based electrodes can produce heat, interfere with the MRI images by creating bright spots that block views of the actual area in the brain being studied, and can become magnetized and move or vibrate when patients undergo scans, causing discomfort.

Carbon proves safer

"Our lab testing shows that unlike the metal electrode, the glassy carbon electrode does not get magnetized by the MRI, so it won't irritate the patient's brain," said Surabhi Nimbalkar, first author and doctoral candidate.

In addition, it can read both chemical and electrical signals from the brain, while the metal-based electrodes can only read electrical signals, so the carbon material is multi-modal as well as MRI compatible.

"It's supposed to be embedded for a lifetime, but the issue is that metal electrodes degrade, so we've been looking at how to make it last a lifetime," said Kassegne, senior author and professor of mechanical engineering at SDSU. "Inherently, the carbon thin-film material is homogenous - or one continuous material - so it has very few defective surfaces. Platinum has grains of metal which become the weak spots vulnerable to corrosion."

Collaborators at KIT developed a novel instrument which enables precise measurements of vibrations during MRI. Working with the SDSU team, they were able to test the novel carbon electrodes directly in the MRI scanner, and confirm it was a safer, better alternative.

"I was excited to see that our vibration measurement instrument enables this completely new benchmarking of real electrodes, which facilitates the risk analysis" said Erwin Fuhrer, joint first author of the paper who recently completed his Ph.D from KIT.

Fuhrer focused on hardware development and applications for MRI safety tests. This collaboration enabled extensive electrode testing for different interactions for the first time.

"Our simulation results underpinned our experimental results and supported additional insights into the processes involved" said coauthor Pedro Silva, a Ph.D student at Korvink's lab.

Cross-disciplinary collaborations

Kassegne, who holds a patent for the process of electrode fabrication, has been working on thin-film carbon in his lab for more than 10 years, but became involved in customizing it for neurological applications when collaborators at the University of Washington and the Massachusetts Institute of Technology reached out to him for his expertise in micro- and nano-fabrication technologies.

Together, the three institutions are part of the National Science Foundation-funded Center for Neurotechnology, looking at engineering new ways to help the brain and spinal cord heal and recover from injury.

The micro-MRI group at KIT, lead by Jan Korvink, works on MRI technologies for the brain, specifically MRI microscopy, an important prerequisite to analyze the behavior of these small electrodes with high-resolution details. Kassegne and Korvink met at a conference and decided to work together on the project.

"Inventing ways to make the MRI machine see more details of the brain is our key mission", said Korvink, joint senior author of the paper.

Nimbalkar, a doctoral student in Kassegne's lab who has two pending patents, focuses on designing and fabrication of electrodes that would be compatible with the MRI process. She worked with Marty Sereno, director of SDSU's MRI Center, to test the carbon material.

"We scanned the electrodes using different imaging sequence techniques and found glassy carbon causes much less distortion of the image," Sereno said. "Metal disturbs the magnetic field which causes distortion, but carbon fiber has less induced currents in the magnetic field, so it won't exert any force on the electrode itself, which is an advantage because it's embedded in the soft tissue of the brain."

With lab testing completed, Kassegne's collaborators on the clinical side will now test the carbon electrode in patients, while Nimbalkar and Kassegne work on testing different forms of carbon to be used in future electrodes.

NASA's Terra satellite captured an image of Typhoon Kalmaegi as it moved into the Luzon Strait and continued to affect the northern Philippines.

On Nov. 19, Kalmaegi's western edge was in the Luzon Strait, while its southern quadrant was over the northern Philippines. The Luzon Strait is located between Taiwan and Luzon, Philippines. The strait connects the Philippine Sea to the South China Sea in the northwestern Pacific Ocean.

Kalmaegi is known locally in the Philippines as Tropical Cyclone Ramon, and there are many warning signals in effect for the northern Philippines.

Signal #3 is in effect for the Luzon provinces of Northern portion of Cagayan (Santa Praxedes), Claveria, Sanchez Mira, Pamplona, Abulug, Ballesteros, Aparri, Calayan, Camalaniugan, Buguey, Santa Teresita, Gonzaga and Santa Ana. Signal #2 is in effect for the Luzon provinces of Batanes, Apayao, Kalinga, Abra, Ilocos Norte & Sur and the rest of Cagayan. Signal #1 is in effect for the Luzon provinces of Northern portion of Isabela (Sta. Maria), San Pablo, Maconacon, Cabagan, Sto. Tomas, Quezon, Delfin Albano, Tumauini, Divilacan, Quirino, Roxas, Mallig, San Manuel, Burgos, Gamu and Ilagan City, Mountain Province, Benguet, Ifugao, La Union, and Pangasinan.

On Nov. 19, the Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA's Terra satellite provided a visible image of Kalmaegi. The MODIS image showed the hint of an oblong eye covered by high clouds. Forecasters at the Joint Typhoon Warning Center noted that eye had collapsed due to deteriorating environmental conditions.

At 10 a.m. EST (1500 UTC), Typhoon Kalmaegi was located near 19.4 degrees north latitude and 122.5 degrees east longitude. That is about 301 nautical miles north-northeast of Manila, Philippines. The storm is barely moving, however. It is moving to the west at 1 knot (1 mph/1.8 kph). Maximum sustained winds were near 75 knots (86 mph/139 kph).

Kalmaegi is turning toward a southwesterly course, which will take it across northwestern Luzon (northern Philippines). The storm will start to weaken, later rapidly, as it moves into the South China Sea.

NASA's Terra satellite is one in a fleet of NASA satellites that provide data for hurricane research.
Typhoons and hurricanes are the most powerful weather event on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

Did Donald Trump's 2016 presidential campaign benefit from voters' fears of immigrants in communities experiencing greater demographic change?

New research shows the answer is "no," a finding that contradicts the conventional wisdom and which surprised even the political scientists who conducted the study. Instead, those communities actually moved more toward the pro-immigration Democratic candidate.

In a paper published in the Proceedings of the National Academy of Sciences, political scientists Daniel J. Hopkins of the University of Pennsylvania, Seth J. Hill of the University of California, San Diego, and Gregory A. Huber of Yale University, describe their novel approach to the question.

They were looking to see if demographic changes from 2012 to 2016 shifted voters toward an anti-immigration presidential candidate.

Rather than look at large geographic areas like counties, as previous studies have, they analyzed a much smaller section of communities: voting precincts.

The challenge with using U.S. counties to study the question is that some are sparsely populated and others have millions of residents, says Hopkins. He and his colleagues wanted to drill down to a more precise and local level.

Hopkins has been studying the question of local demographic changes and influxes of immigrants for years. His prior work and that of others has indicated that those changes should be expected to produce shifts in local politics, he says.

"One of the key things I've found is that people, in explaining their unease about immigration, talk about very local encounters. They say it's challenging to see all of the grocery store signs in Spanish, or that on the phone the bank asked them if they wanted to 'Press 1' for English or 'Press 2' for Spanish," he says. "We were very interested in whether local demographic changes were part of the explanation for the election of Donald Trump, and more generally for the rise in anti-immigration populist political parties and candidates in recent years."

The three researchers teamed up to collect the deep and unique data set. They compiled election results and demographic measures for more than 26,000 precincts in Florida, Georgia, Michigan, Nevada, Ohio, Pennsylvania and Washington.

They chose states that were large, diverse, and politically contested and that jointly captured some of the key demographics that drive American politics: States with large cities like Pennsylvania; western states with large Latino or Asian American populations like Washington; key northeastern and midwestern post-industrial states that were decisive in 2016, like Ohio and Michigan; and larger southern states with very diverse populations, like Florida and Georgia.

They had to work with secretaries of state and state election offices to get individual-level voter turnout data, and then they worked with those offices or other scholars to identify precinct-level electoral data. Precincts are quite small, often with just 1,000 voters, and the researchers contended they would be a much better measure of people's local, lived experiences in their immediate communities.

"A common argument for why candidate Trump won the 2016 election is that he benefited from local demographic changes in the lives of native whites. Our evidence does not support that argument," Hill says. "While it is possible Trump benefited from anti-immigrant sentiment, in the states we examined his vote gains relative to 2012 do not seem to follow from Americans' local lived experience with immigration or demographic change."

Meanwhile, Trump's opponent Hillary Clinton saw increases in votes in precincts with growing shares of Hispanics and immigrants. While the authors cannot make a causal claim about why Clinton benefited, they use their precinct observations to show that even in precincts that strongly voted Republican in 2012, increasing diversity led to movement toward Clinton. This implies the overall pattern was not generated simply by immigrants and Hispanics moving exclusively into already heavily Democratic precincts.

"It may be that native-born citizens have some discomfort with demographic change but that discomfort either declines over time or it is not as important for their presidential-vote choice as factors such as policy views or candidate characteristics," Hill says.

Nationalization is a powerful trend, Hopkins says, and immigration-related political appeals can resonate in a wide range of different communities.

"We're not saying that demographic change doesn't reshape our politics, but what we are saying is that demographic changes at the local level do not seem to be what drove many voters to Donald Trump."

AMES, Iowa - NASA's planet-hunting TESS Mission keeps giving astronomers new realities to examine and explain.

Case in point: astronomers using the tools of asteroseismology - the observations and measurements of a star's oscillations, or starquakes, that appear as changes in brightness - have learned more about two stars bright enough to be visible in a dark sky to the naked eye. These red-giant stars - older, "retired" stars no longer burning hydrogen in their cores - are known as HD 212771 and HD 203949.

Both stars are known to host their own planets. And the TESS data indicate one of those "exoplanets" (the general term for planets that orbit stars other than our sun) is so close to its host star it shouldn't have survived the star's expansion as a red giant - if, that is, the star is old enough to have expanded and retreated.

Steve Kawaler, an Iowa State University distinguished professor of physics and astronomy, and Miles Lucas, a recent Iowa State graduate and current doctoral student at the University of Hawaii at Manoa, are part of the TESS asteroseismology study team.

"We listened to the notes the stars were singing," Kawaler said. "We used that data to determine actual values - mass, radius and evolutionary stage - for these stars. Asteroseismology can tell us all these things - and more - about stars that are difficult to obtain with other tools."

The team of 48 astronomers describe their findings in a paper recently published by The Astrophysical Journal. The lead author is Tiago L. Campante of Portugal's Universidade do Porto.

The paper describes the first use of TESS data to detect oscillations of stars already known to host exoplanets. The new work, the authors wrote, is a way of "further showcasing the mission's potential to conduct asteroseismology of red-giant stars."

Kawaler said the study indicated star HD 203949 was less massive than previously thought. That meant for its planet to be moving as fast as the astronomers determined, it had to be much closer to the star than expected. So close, in fact, it would be engulfed by the star's expansion as a red giant.

The paper offers two possible explanations: The host star is early in its red giant expansion and has yet to engulf and destroy the planet. Or, computer simulations of star-planet tides indicate the planet could have been dragged from a wider orbit, where it avoided destruction by the star, and then settled into a closer orbit once the star retreated.

It's an interesting case of planetary evolution, said Kawaler, who's on the seven-member board leading the TESS Asteroseismic Science Consortium. Jørgen Christensen-Dalsgaard of Aarhus University in Denmark is the consortium's lead investigator.

"Tiago (the paper's lead author) has a knack for finding these planetary systems that expand our horizons on how nature makes planets and keeps them," Kawaler said.

As astronomers continue to analyze data for clues about how planets and stars evolve with each other, Kawaler said TESS is an important tool.

TESS - the Transiting Exoplanet Survey Satellite, led by astrophysicists from the Massachusetts Institute of Technology - launched in April 2018. The spacecraft and its four cameras are on a two-year mission to survey 85 percent of the sky, looking for planets by detecting tiny dips of light as they pass in front of their host stars.

Those cameras also collect star data that are useful for planetary studies, too.

"Characterization of host stars is a critical component of understanding their planets," the authors wrote. " ... The asteroseismology techniques described here are thus an important component of overall planetary system characterization."

Steep gradients of wind stress and potential temperature enable sustainable nearshore precipitation systems along the western coastal region of Korea, according to Prof. Dong-In Lee, lead scientist at the Group of Environmental Atmospheric Research (GEAR), Pukyong National University, and one of the authors of a recently published study.

"Coastal precipitation, which refers to the occurrence of heavy precipitation in coastal areas, has always been an interesting study area, but it is difficult to prove its cause from the mesoscale point of view, although surface discontinuity is known to play an important role," says the corresponding author of the study, Prof. Lee. "In order to reveal the effect of surface discontinuity on coastal precipitation from the mesoscale perspective, we investigated the process of momentum transportation using the radar-retrieved wind field and a model experiment."

By using observational data from two S-band radars, C-band radar, and surface weather variables, Prof. Dong-In Lee and his team--a group of researchers from GEAR at Pukyong National University, the New and Renewable Energy Resource Center at the Korea Institute of Energy Research, and the Storm, Flood and Landslide Research Department at the National Research Institute for Earth Science and Disaster Resilience--have had their findings on the causes of coastal precipitation in the western region of Korea published in Advances of Atmospheric Sciences.

In order to verify the effect of surface discontinuity in the coastal region, the team investigated the coastal precipitation on 26 July 2011. Using three-dimensional wind fields and model experiments, they proved the effect of surface discontinuity on sustainable precipitation systems.

Radar analysis clearly showed that a change in wind at the surface border played an important role in the development of the nearshore convection system. The simulation results, which were very similar to the observations, showed that the surface border generated and maintained the convergence zone. The surface roughness change enhanced the convergence, and the interaction between the deepening cold pool and downward flow maintained the convergence zone. The surface mechanical discontinuity affected by the roughness change between sea and land formed the convergence, which induced energy transfer.

Prof. Lee believes that "The presence of the coast can contribute to sustaining precipitation. A key point of the paper is that changes of roughness can contribute to the sustained development of precipitation in coastal areas. We are preparing an idealized experiment based on the results of this study and will investigate the microphysical processes of coastal precipitation through DSD [drop size distribution] observations in the future."

When mice learn to do a new task, their brain activities change over time as they advance from 'novice' to 'expert.' The changes are reflected in the wiring of cell circuits and activities of neurons.

Using a two-photon imaging microscope and a wealth of genetic tools, researchers from Cold Spring Harbor Laboratory (CSHL), Columbia University, University College London, and Flatiron Institute found that neural networks become more focused as mice got better at performing a trained task. They used the data to construct computational models that can inform their understanding of the neuroscience behind decision-making.

"We recorded the activity from hundreds of neurons all at the same time, and studied what the neurons did over learning," said CSHL Associate Professor Anne Churchland. "Nobody really knew how animals or humans learn the structure of a task and how the neural activity supports that."

The team, including Farzaneh Najafi, the first author on the study and a postdoctoral fellow in Churchland's lab, started by training mice on perceptual decision-making tasks. The mice received multisensory stimuli in the form of a sequence of clicks and flashes that were presented together. Their job was to tell researchers whether those are happening at a high or low rate by licking one of three waterspouts in front of them.

They licked the middle spout to start the trial, one side to report a high-rate decision and the other side for a low-rate decision. When the mice made the correct decision, they received a reward.

"Most decision-making studies focused on the period where the animals are really experts. But we were able to see how they arrive at the state by measuring the neurons in their brain all the way through learning," said Churchland, the senior author on the study. "We found that in all the animals, their learning occurs gradually over about four weeks. And we found that what supports learning is activity changes in a whole bunch of neurons."

The neurons, the team discovered, became more selective in responding to an activity associated with a particular task. The also started reacting faster and more immediately.

"They'll respond really strongly in advance of one choice and much less so in advance of the other choice," Churchland said.

When the animals are just beginning to learn, the neurons don't respond until around the time it makes the choice. But as the animal gains expertise, the neurons respond much further in advance.

"We can kind of read the animal's mind in a way, we can predict what the animal is going to do before he does it," Churchland said. "When you're a novice at something your brain is doing all different things, so you have neurons engaged in all different things. But then when you're an expert, you hone in on exactly what you're going to do and we can pick up that activity."

The researchers decoded neural activity by training a small artificial network called the 'Linear Support Vector Machine' using machine learning algorithms. It collects performance data from multiple trials and combines it with the activity of all the neurons, weighing them to make a guess about what the animal's going to do. As the animal gets better at the task, its neural networks get more refined, precise and specific. The researchers are able to mirror that onto the artificial network, which can then predict the animal's decision with about 90 percent accuracy.

The learning models also offer another way of looking at specific types of neurons in the brain involved in cognition, like excitatory and inhibitory neurons, which trigger positive and negative changes, respectively. In this study, published in Neuron Cell Press, the team found that the inhibitory neurons are part of very selective sub-networks in the brain, and they're strongly selective for the choice that the animal's going to make.

These neurons are part of a biophysical model that helps researchers understand how decision making works. As researchers refine these models, they're able to make more sense of how cognition informs behavior.

"We've learned a lot about perceptual decision-making-the decisions that a subject would get right and wrong, how long it takes to make those decisions, what the neural activity would look like during decision-making-by making different kinds of models that make really concrete predictions," Churchland said. "Now we can understand, hopefully better, why these very selective sub-networks are there, how they help us make better decisions, and how they are wired up during learning."

In a boon to wind farms, average daily wind speeds are picking up across much of the globe after about 30 years of gradual slowing. Research led by a team at Princeton University shows that wind speeds in northern mid-latitude regions have increased by roughly 7% since 2010.

The findings mark a reversal of the pattern of declining winds in these regions since the 1980s -- a phenomenon known as global terrestrial stilling. Focusing on regions of North America, Europe and Asia where wind power is on the rise, the researchers analyzed wind speed records collected between 1978 and 2017 from more than 1,400 weather stations. In a paper published Nov. 18 in Nature Climate Change, they showed that while wind speeds decreased by about 2.3% per decade beginning in 1978, since 2010 wind speeds have increased at a rate that is nearly three times faster.

The research, which looked only at regional averages, did not examine how the uptick in wind speeds might affect the severity of storms, which also has been increasing.

The team examined the potential causes underlying global terrestrial stilling and its reversal. While changes in urbanization and vegetation have been proposed as contributors to global terrestrial stilling, these trends have not reversed since 2010, said Zhenzhong Zeng, who led the study as a postdoctoral researcher working with Eric Wood, Princeton's Susan Dod Brown Professor of Civil and Environmental Engineering, Emeritus.

Zeng and his colleagues used statistical methods to test associations between variations in wind speed and an array of well-characterized ocean-atmosphere oscillations. Ocean-atmosphere oscillations, which alter distributions of heat and pressure, had long been understood to drive ocean wind speeds, and this study demonstrated the global relationship between the oscillations and land-based wind speeds.

The analysis showed that in each region of the globe, specific large-scale ocean-atmosphere oscillations, which are driven by many factors including the uneven heating of the earth's surface in different regions, were likely explanations for the observed trends in wind speeds.

Extending their findings to wind power generation, the researchers calculated that a typical wind turbine receiving the global average wind would have produced about 17% more energy in 2017 than in 2010. And using climate indices to project future wind speeds, they predicted a 37% increase by 2024.

Wind speed trends may account for much of the United States' increase in wind energy production efficiency from 2010 to 2017, whereas technological innovations in wind turbines may have played a smaller role than is often assumed, said Zeng, who is now an associate professor at the Southern University of Science and Technology in Shenzhen, China.

"We predict that the increasing wind speed trend will continue for 10 years, but we also show that because this is caused by ocean-atmosphere oscillations, maybe a decade later it will reverse again," he said. And since the lifespan of a wind turbine is usually 20 years at most, having reliable projections of wind speeds at particular locations could be crucial to making smart investments in wind power and increasing the global share of renewable energy.

"Knowing about possible downtrends in wind speeds in the longer term can indeed be very useful for planning of future wind power infrastructure," said Charles Meneveau, a mechanical engineering professor at Johns Hopkins University who was not involved in the study. "This type of research, blending geosciences and engineering to elucidate phenomena of great societal significance, is timely and will increase our understanding of the close connections between climate and society."

Two fundamental goals of humanity are to eradicate poverty and reduce climate change, and it is critical that the world knows whether achieving these goals will involve trade-offs. New IIASA research for the first time provides a basis to answer this question, including the tools needed to relate basic needs directly to resource use.

Researchers have been grappling with the question of how much energy societies actually need to satisfy everyone's most basic needs for many years, but as global scenarios of climate stabilization assume strong reductions in energy demand growth in the face of the climate crisis - especially in developing countries - finding an answer is becoming crucial. In their study published in the journal Nature Energy, IIASA researchers attempted to find out whether meeting everyone's most basic human needs is in fact an impediment for stabilizing climate change.

"People have long worried that economic development and climate mitigation aren't compatible - that the growth required to bring billions of people out of poverty would make it impossible to reduce net emissions to zero - which is a requirement for climate stabilization. Until now, the research community however had no way to separate out the energy needs for eradicating poverty from countries' overall demand growth. Without this, vast inequalities and unsustainable consumption patterns in developing countries were being ignored," explains study lead author Narasimha Rao, a researcher in the IIASA Energy Program, who is also on the faculty of the Yale University School of Forestry and Environmental Studies.

The researchers chose three developing countries, Brazil, India, and South Africa, and for each country asked what material requirements were underpinning basic human needs; and how the energy resources required to meet these basic needs vary in different contexts (e.g., climate or culture) within each country. In order to do this, they developed a new way of deriving energy demand from basic services rather than from economic growth, so that energy for poverty eradication could be separated from those for affluence.

The results show that the energy needs for providing decent living standards to all in the chosen countries are well below their current national energy use, and also well below average global energy use per capita. Energy for providing good health and education is far less than that for physical infrastructure, transit and buildings. These energy needs can however be further reduced if countries provide extensive affordable public transit and use local materials in building construction.

"We didn't expect that the energy needs for a minimally decent life would be so modest, even for countries like India where large gaps exist. It was also a pleasant surprise that the most essential human needs related to health, nutrition, and education, are cheap in terms of energy. Along the way, we also found that measuring poverty in terms of these material deprivations far exceeds the World Bank's definition of income poverty," Rao elaborates.

The findings further indicate that affluence, more than basic needs, drives energy demand, and that the bulk of future energy growth in these countries will likely serve the middle classes and affluent, even if governments prioritized poverty eradication. This suggests that close attention should be paid to lifestyles and how they evolve in developing countries. The researchers further emphasize that developing countries have different resource needs to meet the same human development goals. Brazil, for instance, has comparably high energy intensity of mobility due to a high dependence on cars. Because of these differences, developing countries will face different costs and challenges to reduce greenhouse gas emissions from raising citizens' quality of life above a basic standard. Future pledges in the Paris Agreement will have to consider these differences to ensure that countries perceive their efforts as comparable and fair.

"Eradicating poverty need not stand in the way of stabilizing climate at safe levels. Our study suggests that we need to measure societal progress in terms of these multiple dimensions, not just income, and we should also pay attention to the distribution of growth in developing countries. This can point us to new ways to improve wellbeing while reducing emissions. Policymakers should give particular attention to investing in public transit, green and locally sourced buildings, and encouraging sustainable diets and food systems. These insights can inform current negotiations under the Paris agreement. Countries should take stock and step up the ambition in their pledges," Rao concludes.

OAK RIDGE, Tenn., Nov. 18, 2019--A scientific team from the Department of Energy's Oak Ridge National Laboratory and Vanderbilt University has made the first experimental observation of a material phase that had been predicted but never seen. The newly discovered phase couples with a known phase to enable unique control over material properties--an advance that paves the way to eventual manipulation of electrical conduction in two-dimensional (2D) materials such as graphene.

The team made the discovery using a layered, copper-containing crystal that is ferroelectric, or has a constant electric dipole that can be reversed when an electric field is applied.

"These materials may become building blocks of ultrathin energy and electronics technologies," said ORNL's Nina Balke, a corresponding author of a paper reporting the finding in Nature Materials.

The observation shows properties that can be harnessed to provide materials with new functions. These properties depend on the locations of copper atoms in the crystal. The copper atoms can either sit within the layers of the crystal or become displaced into the gaps between layers--called "van der Waals gaps"--where they make weak ionic bonds with neighboring layers and form the new phase.

The scientists measured electromechanical responses throughout layered ferroelectric crystals of copper indium thiophosphate, or CIPS. This material is piezoelectric, meaning its surfaces become charged when it is stretched or squeezed. Conversely, applying an electric field makes a piezoelectric material expand or contract. The piezoelectric properties of CIPS were the key to studying it experimentally as well as theoretically to reveal the new phenomena.

The theoretical research was carried out by the group of Sokrates Pantelides, a professor at Vanderbilt University and distinguished visiting scientist at ORNL. Using quantum calculations, group members moved the atom responsible for polar displacement--copper--through the crystal structure and calculated the potential energy. "A typical outcome for a ferroelectric material is that you have two energy minima, or 'wells,' for this atom; each one represents a polarization vector, one pointing up, the other down," said Pantelides. "For this material, theory predicted four energy minima, which is extremely unusual."

The research team found that the two additional energy minima arise from a second structural phase with double the polarization amplitude and with a stable position for the copper atom in the van der Waals gap. Moreover, the theoretically predicted piezoelectric constants for the two polar phases in CIPS matched the experimentally measured ones.

"This is the first reported observation of the piezoelectric and ferroelectric properties of the high-polarization phase," said Balke, the leading experimentalist on the team. "It was known that copper can go in the gap, but the consequences for piezoelectric and ferroelectric properties were not known. But in the end, that's what forms the quadruple well."

Sabine Neumayer, a member of the ORNL team, added, "The quadruple well opens up a lot of exciting opportunities, especially because we can control transitions between these four different polarization states using temperature, pressure and electric fields." Usually, ferroelectrics are thought of as switches between two states. In CIPS, four states are accessible.

"CIPS is one of the first ferroelectric materials that is natively compatible with nearly all 2D materials because of its van der Waals structure. Anytime you have van der Waals forces, it means that you can put 2D materials together and separate them without causing major structural damage," Peter Maksymovych, another corresponding author, said. "The van der Waals structure is what enables cleaving of bulk crystals to create 2D nanostructures with clean surfaces."

Scientists worldwide have been racing to create an active interface for 2D materials like graphene, a single-atom-thick material with very high electron mobility. "We imagine that in the future, an active interface to CIPS can control graphene via piezoelectric, ferroelectric and other responsive properties," Maksymovych said. "It'll put the smarts into graphene."

Michael McGuire in ORNL's Materials Science and Technology Division grew and characterized the study's crystals with Michael Susner, now at the Air Force Research Laboratory. "The competition and coexistence of multiple phases in the crystals makes these materials particularly exciting and interesting," he said. "The ability to study complex materials like these both theoretically and experimentally over a wide range of length scales with complementary techniques makes this type of work possible at ORNL."

The researchers ran experiments at ORNL's Center for Nanophase Materials Sciences, where unsurpassed instrumentation and expertise enabled precise measurements and clear analysis and interpretation of complex data. The experiments relied on piezoresponse force microscopy (PFM) to image and control ferroelectric domains on scales of millionths to billionths of meters. A sharp conductive probe applies an electric field to a sample's surface, and the material's electromechanically induced deformation is inferred from the probe's displacement.

"CNMS is the world-leading institution in piezoresponse force microscopy," said Maksymovych. "People come here from across the world to measure properties of their samples." A big draw is close consultation with PFM group members providing nearly half a century of cumulative expertise from innovators in PFM such as Sergei Kalinin and Stephen Jesse, and top names in theory, such as Panchapakesan Ganesh and Sokrates Pantelides--all authors on this paper. "Without that longstanding expertise, the measurement itself alone might have not resulted in the cohesive picture we gained," Balke said.

Maksymovych added, "Interpreting data for double wells is challenging. Quadruple wells are even more complex because now you have multiple switching properties. The sequence of expansion and contraction can look bizarre and unclear. Only due to Nina's and Sabine's effort was the bizarreness normalized so we could understand exactly what is going on."

In future studies, the researchers will probe dynamic properties--observing ratios of high and low polarization in strained materials; moving, stabilizing and embedding atoms of the new phase to make a switch; experimentally probing predicted behavior of materials under pressure; and studying how ferroelectric domains reorient after an electric field is applied.

Every day, more than 141 billion liters of water are used solely to flush toilets. With millions of global citizens experiencing water scarcity, what if that amount could be reduced by 50%?

The possibility may exist through research conducted at Penn State, released today (Nov. 18) in Nature Sustainability.

"Our team has developed a robust bio-inspired, liquid, sludge- and bacteria-repellent coating that can essentially make a toilet self-cleaning," said Tak-Sing Wong, Wormley Early Career Professor of Engineering and associate professor of mechanical engineering and biomedical engineering.

In the Wong Laboratory for Nature Inspired Engineering, housed within the Department of Mechanical Engineering and the Materials Research Institute, researchers have developed a method that dramatically reduces the amount of water needed to flush a conventional toilet, which usually requires 6 liters.

Co-developed by Jing Wang, a doctoral graduate from Wong's lab, the liquid-entrenched smooth surface (LESS) coating is a two-step spray that, among other applications, can be applied to a ceramic toilet bowl. The first spray, created from molecularly grafted polymers, is the initial step in building an extremely smooth and liquid-repellent foundation.

"When it dries, the first spray grows molecules that look like little hairs, with a diameter of about 1,000,000 times thinner than a human's," Wang said.

While this first application creates an extremely smooth surface as is, the second spray infuses a thin layer of lubricant around those nanoscopic "hairs" to create a super-slippery surface.

"When we put that coating on a toilet in the lab and dump synthetic fecal matter on it, it (the synthetic fecal matter) just completely slides down and nothing sticks to it (the toilet)," Wang said.

With this novel slippery surface, the toilets can effectively clean residue from inside the bowl and dispose of the waste with only a fraction of the water previously needed. The researchers also predict the coating could last for about 500 flushes in a conventional toilet before a reapplication of the lubricant layer is needed.

While other liquid-infused slippery surfaces can take hours to cure, the LESS two-step coating takes less than five minutes. The researcher's experiments also found the surface effectively repelled bacteria, particularly ones that spread infectious diseases and unpleasant odors.

If it were widely adopted in the United States, it could direct critical resources toward other important activities, to drought-stricken areas or to regions experiencing chronic water scarcity, said the researchers.

Driven by these humanitarian solutions, the researchers also hope their work can make an impact in the developing world. The technology could be used within waterless toilets, which are used extensively around the world.

"Poop sticking to the toilet is not only unpleasant to users, but it also presents serious health concerns," Wong said.

However, if a waterless toilet or urinal used the LESS coating, the team predicts these types of fixtures would be more appealing and safer for widespread use.

To address these issues in both the United States and around the world, Wong and his collaborators, Wang, Birgitt Boschitsch, and Nan Sun, all mechanical engineering alumni, began a start-up venture.

With support from the Ben Franklin Technology Partners' TechCelerator, the National Science Foundation, the Department of Energy, the Office of Naval Research, the Rice Business Plan Competition and Y-Combinator, their company, spotLESS Materials, is already bringing the LESS coating to market.

"Our goal is to bring impactful technology to the market so everyone can benefit," Wong said. "To maximize the impact of our coating technology, we need to get it out of the lab."

Looking forward, the team hopes spotLESS Materials will play a role in sustaining the world's water resources and continue expanding the reach of their technology.

"As a researcher in an academic setting, my goal is to invent things that everyone can benefit from," Wong said. "As a Penn Stater, I see this culture being amplified through entrepreneurship, and I'm excited to contribute."

In species with sexual reproduction, no two individuals are alike and scientists have long struggled to understand why there is so much genetic variation. In a new study published in Nature Ecology & Evolution, a team of researchers from the University of Uppsala in Sweden now show that a genetic tug-of-war between the sexes acts to maintain variation.

For important traits such as lifespan and metabolism, the interests of the sexes can differ. In many species, males favour a "live-fast-and-die-young" lifestyle whereas a slower pace of life is beneficial for females. This sexual conflict can lead to different gene variants being favoured in males and females, which can lead to a balance in which both variants, one being good for males and one for females, are maintained in populations. The team from Uppsala analysed the DNA sequence of many thousands of genes in great detail and found a clear footprint of this sort of balance in different populations of beetles.

"We were surprised to see that hundreds of different genes are apparently involved in sexual conflict," says Professor Göran Arnqvist, who led the research team. "Most of the genes that showed this form of balance were genes that are turned on, or expressed, more in females than in males and were genes known to affect metabolism and reproduction."

"Many of these genes are of really fundamental importance for male and female life histories, so this form of genetic conflict between the sexes seems to contribute in a very important way to the maintenance of genetic variation," Arnqvist continues. "Differences between males and females can, apparently, help create genetic diversity."

The endangered Hawaiian duck, or koloa, the only endemic duck remaining on the main Hawaiian Islands, is threatened with genetic extinction due to interbreeding with feral mallards. This has led to the creation of hybrid forms of the koloa. But new research has found that the genetic diversity of the koloa is high, and conservation efforts on the island of Kauai have been successful.

Caitlin Wells, a research scientist at Colorado State University, conducted the research as a postdoctoral scholar at the University of California, Davis. This study is the culmination of two decades of research spearheaded by scientists from University of California, Davis; U.S. Fish and Wildlife Service; University of Texas, El Paso; Wright State University; Oregon State University; and the state of Hawaii's Division of Forestry and Wildlife.

The results from the study offer hope for existing conservation efforts with the koloa and other endangered birds around the world.

"Persistence of an endangered native duck, feral mallards, and multiple hybrid swarms across the main Hawaiian Islands," will be published Nov. 18 in Molecular Ecology, and Wells is the lead author.

A charismatic duck, located primarily on Kauai

Wells described the koloa as a "petite, buffy brown and charismatic duck," similar to a female mallard.

"The fact that the koloa on Kauai are pure and have a lot of genetic variation are two really positive things that came out of this study," said Wells.

Andy Engilis, study co-author and curator of the UC Davis Museum of Wildlife and Fish Biology, said this study is pivotal in the struggle to save koloa from extinction. He has been involved in conservation efforts and research of Hawaiian ducks since the late 1980s.

"This study lays the foundation for a new chapter in the recovery of the koloa, a new trajectory towards recovery and delisting as an endangered species," he said.

Kimberly Uyehara, a Kauai National Wildlife Refuge Complex biologist and co-author of the study, said the findings are significant.

"They open new doors to the realm of possible recovery actions for koloa," she explained.

The largest population of koloa is on Kauai, where the team found very few hybrid birds. On the other islands, however, all of the birds were hybrids or feral mallards.

Historically, koloa existed throughout the main Hawaiian islands, but they disappeared from all islands except Kauai and Niihau by the late 1960s due to habitat loss, introduced predators and unregulated hunting. Soon after, wildlife managers began captive breeding and release programs on Oahu, Hawaii and Maui to re-establish the koloa. Unfortunately, mallards were never removed on these islands, resulting in rapid hybridization.

This research study was conducted, in part, to determine the genetic makeup of koloa on Kauai. Previously, wildlife managers and conservationists raised concerns that even the refuges on Kauai contained hybrid ducks.

Research project involved an immense bird banding project

The research team studied 425 koloa, mallards and hybrids from populations across the Hawaiian Islands, gathering more than 3,300 genetic data points from the birds. The project involved a massive bird-banding project led by collaborators at Oregon State and the Hanalei National Wildlife Refuge. Members of the team collected blood samples from hundreds of the birds before releasing them back into the wild.

The researchers also gathered genetic data from the carcasses of koloa retrieved following botulism outbreaks, particularly in the Kauai population. All of the specimens and samples are archived at the UC Davis Museum of Wildlife and Fish Biology.

"We used a lot of tissue samples from salvaged birds that unfortunately died from those disease outbreaks," said Wells.

Previously, wildlife managers had thought that if they left the koloa hybrids alone, the birds would eventually return to pure koloa on their own.

"That's not what we found," explained Wells. "If you don't have pure koloa parents that outnumber the feral mallards, you're not going to get any decreases in those hybrid proportions."

Why preserve the koloa?

The recovery of the endangered koloa is important because the bird is endemic to the Hawaiian Islands.

"Its recovery could be viewed as a beacon of hope for the many dozens of critically endangered birds found in the islands," said Engilis. Researchers also point out that its recovery is important because of its unique evolutionary history.

"Should the environment change, due to things like climate change, there's a lot of potential for the koloa to evolve on its own, given the genetic diversity we've seen," said Wells.

Hybridization of species is a tricky issue in conservation. Sometimes, it can threaten a unique gene pool of an animal that is well-adapted to its environment. In other cases, where a species is inbred, it might be the right move to add more genetic diversity to a population.

"But here's a case where we have enough individuals with enough genetic variation in the koloa, and we've also genetically identified the hybridizing species," she said. "It seems very clear that we can separate those going forward."

What's next for koloa conservation

Wells said the team's research provides insight on successful conservation management and the ability to recover this species.

"These efforts might one day eventually lead to the koloa being taken off the endangered species list," she said.

Researchers have designed multiplayer games occupants of autonomous vehicles can play with other players in nearby self-driving cars.

A new study, led by researchers from the University of Waterloo details three games created for level three and higher semi-autonomous vehicles. The researchers also made suggestions for many exciting types of in-car games for future exploration.

Level three and higher semi-autonomous vehicles are those that have, at minimum, environmental detection capabilities and can make informed decisions for themselves.

"As autonomous vehicles start to replace conventional vehicles, occupants will have much more free time than they used to," said Matthew Lakier, a PhD student in Waterloo's School of Computer Science. "You could use time spent in commute to read a book, watch a movie, get ahead on work, or browse the internet. Still, not everything you do has to be all isolated.

"You will be able to play games with other people in autonomous vehicles nearby when the car is driving itself. The games will be imposed on top of the actual world, so drivers won't have to take their eyes off the road."

Self-driving cars have many intelligent technologies that help to keep them safe, and the researchers envision that in the future, vehicle-to-vehicle (V2V) communication and heads-up displays (HUDs) will also become standard features. V2V enables cars to let each other know where they are relative to each other on the road, and HUDs on the windshield keep drivers aware of the car's speed and road conditions.

In developing the three games, the researchers first undertook an extensive literature review to identify gaps in previous research done about autonomous vehicles and found that not much attention has been given to cross-car games.

They then developed a virtual reality (VR) driving simulator to render the car cabin, outside environment, and roadway with artificially controlled cars and intelligent computer-controlled players. The VR driving simulator is designed as a framework to enable rapid prototyping of in-car games that leverage future technologies like V2V, full window HUDs, head tracking, and different input methods.

Twelve participants evaluated the three cross-car games. They played the games, with occasional take-over tasks, completed the Player Experience Inventory questionnaire to measure player experience, and answered questions in a semi-structured interview.

"Overall, the participants rated the games highly in immersion, there was a positive response to the incorporation of HUDs in the games, and the different game styles did not significantly impact the take-over task completion time. All games were popular for different reasons," said Lakier, a member of Waterloo's Human-Computer Interaction (HCI) Lab.

"People were happy to play with strangers. So, for example, they said they could form impromptu relationships with other people on the road."

A new wet suit material tested by Flinders marine researchers can help reduce blood loss caused by shark bites, to reduce injuries and prevent the leading cause of death from shark bites.

The study published in PLOS ONE tested two types of protective fabrics that incorporate ultra-high molecular weight polyethylene fibres (UHMWPE) onto widely used neoprene material in wet suits, and compared their resistance to bites against standard neoprene without protective layers.

Flinders University Associate Professor Charlie Huveneers, from the Southern Shark Ecology Group, says new technological advances in fabric have allowed the development of lightweight alternatives that can be incorporated onto traditional wet suits.

"The aim of this study was to assess the ability of new fabrics incorporated into neoprene to reduce injuries from White Shark bites," says Assoc Professor Huveneers.

"Our results showed that both fabrics tested may provide some protection against shark bite and could be used as part of a shark bite mitigation strategy."

"We tested the fabric on White Sharks because it is the species responsible for the most fatalities from shark bites."

The tests included 10 variants of two different fabrics using two laboratory tests, puncture and laceration tests, along with field-based trials involving White Sharks ranging 3-4 m.

White Shark bite force was also measured at the Neptune Islands Group Marine Park using load sensors placed between steel plates surrounded by foam.

"We found that the new fabrics were more resistant to puncture, laceration, and bites from White Sharks than standard neoprene."

"More force was required to puncture the new fabrics compared to control fabrics (laboratory-based tests), and cuts made to the new fabrics were smaller and shallower than those on standard neoprene from both types of test, i.e. laboratory and field tests.

Prof Huveneers says the results are positive but more testing is required in an incorporated wet suit design and on the potential damage to human flesh underneath for more robust recommendations.

"Although these fabrics may reduce blood loss resulting from a shark bite, further research is needed to measure the magnitude of injury to human flesh."

Atmospheric reactive nitrogen (N) deposition has more than doubled over the past century.  It is very important to estimate the rates and sources of N deposition because it's considered as a main factor of ecosystem structure changes, such as soil acidification, water eutrophication and biodiversity losses, especially in countries with high N deposition, such as China. However, it is very difficult to obtain monitoring data of atmospheric N deposition because of the complexity of N species and the diversity of deposition forms.

Mosses are very widespread. Almost all of nitrogen for mosses growth are from air and rainfall. Therefore, many researchers investigate N deposition levels and its effects by using moss, especially in Europe and Southwest China. However, whether mosses can be used to monitor atmospheric N deposition in the Yangtze River Delta (YRD) region has yet to be determined.

"We collected rainwater and moss tissue at six monitoring sites in the YRD with three land-use types--urban, suburban, and rural and analyzed moss (Haplocladium microphyllum) N content, wet N deposition rate, and their N isotope signatures." says Dr. Tao Huang, from the School of Geography, Nanjing Normal University.

Based on this study, they found a significant linear relationship between moss N content and wet N deposition rate. In addition, they also determined a consistent decreasing trend for moss N content and wet N deposition from urban to suburban to rural areas. The more negative N isotopic signature of suburban and rural mosses indicated N is mainly released from agricultural ammonia, while the less negative N isotopic signature of urban mosses highlighted a main influence from fossil fuel combustion and traffic emissions. The findings are published in Atmospheric and Oceanic Science Letters.

"The important revelation of our study is that the epilithic moss Haplocladium microphyllum can bio-monitor the rates and sources of atmospheric N deposition in the YRD, making up for the lack of monitoring data of N deposition," concludes Dr. Huang.