Tech

Using laser light to trap atoms in a checkerboard-like pattern, a team led by Princeton scientists studied how resistance -- the loss of electrical current as heat -- can develop in unconventional metals.

The results may help explain how certain types of superconductors made from copper oxides are able to conduct electricity so efficiently. The research was published online Dec. 6 in the journal Science.

Superconducting materials are ones that efficiently transmit electricity without losing any of the current as heat. Because they don't waste electricity, they have the potential to boost the energy-efficiency of the electrical power grid. They may also open up possibilities for new technologies.

"If you want to carry electricity in power lines more efficiently, then improving our fundamental understanding of transport in these materials will have a significant impact on our ability to design better materials," said Waseem Bakr, assistant professor of physics and senior author on the study.

Copper oxide superconductors are prized for their ability to work at relatively high temperatures compared to other types of superconductors. The materials were the subject of the Nobel Prize in Physics in 1987.

To explore how resistance develops, the researchers created an experiment that involved trapping atoms in an evenly spaced grid made from intersecting laser beams. The resulting structure, called an optical lattice, holds the atoms like eggs in an egg carton or checkers on a checkerboard.

This setup allows researchers to see what is happening between the atoms. Normally this is not possible because the atoms in a solid are tightly packed.

In this experiment, the atoms are about 10,000 times farther from each other than the atoms in a typical material, which allows researchers to view them using a microscope. The tiny particles are kept at intensely cold temperatures -- just a few billionths of a degree above absolute zero -- to quell their normal jumpiness.

The researchers used the atoms as a stand-in for electrons, the charged particles that carry electrical current. Atoms are easier to image and manipulate than electrons.

"Our lithium atoms in an optical lattice obey the same physics as electrons in real materials," said Peter Brown, a graduate student in physics and first author on the study. "This is advantageous because we have greater control over our system than is possible using real materials -- for example, we can tune the interactions between atoms and change the density of atoms."

To explore how resistance develops, the researchers projected a laser beam onto the atoms in the lattice, creating ripples of density that travel through the atoms. The team measured how quickly the waves died away, which happens because the atoms bump against each other and become out of sync.

The team repeated the experiment for a variety of different temperatures, each time heating up the atoms to a different temperature and observing how the resistance changed with temperature.

They saw two interesting things happen: One was that as the temperature increased, the resistance increased in a linear fashion: an increase in temperature led to a proportional increase in resistance. This was surprising because the simplest theory for these systems, which is called the Fermi liquid theory, predicts a different pattern of response to temperature, where the resistance increases as the square of temperature, so as temperature increases, resistivity increases slowly at first and then rapidly.

This unexpected linear response to temperature is one that is seen in the copper-oxide, or "cuprate," superconductors. This behavior has earned these materials the name "strange metals," and some researchers think that understanding this behavior might shed light on the origin of high-temperature superconductivity.

Another observation the team made is that at high temperatures the resistance exceeds what theorists predicted was possible in those systems. The explanation for this is that the atoms are no longer behaving as discrete particles but rather as a quantum soup where each particle no longer has its own identity. This state happens when a system exceeds a theoretical bound called the Mott-Ioffe-Regel (MIR) limit. Physicists call such materials "bad metals."

This state is interesting because resistance is thought to develop when particles scatter, bouncing off nearby particles like pinballs in a machine. Surpassing the MIR bound implies that the particles do not follow this simple picture.

"Common sense says that a particle cannot scatter until it bounces off another particle. But what we saw was that resistivity keeps increasing and doesn't respect this bound," Bakr said.

David Huse, Princeton's Cyrus Fogg Brackett Professor of Physics and a theorist who specializes in the physics of interacting quantum matter, provided theoretical understanding for the experimental observations. In addition to Huse, Brown and Bakr, the team at Princeton included graduate students Debayan Mitra and Elmer Guardado-Sanchez, and Dicke Postdoctoral Fellow Peter Schauss.

The team collaborated with Reza Nourafkan, Alexis Reymbaut, Charles-David Hebert, Simon Bergeron and Andre-Marie Tremblay at the University of Sherbrooke in Canada; and Jure Kokalj at the Jozef Stefan Institute in Ljubljana, Slovenia.

Related work exploring the spin-conductivity of cold atoms in an optical lattice was performed in the group led by Professor Martin Zwierlein at the Massachusetts Institute of Technology and was published in the same issue of Science.

Your computer performs most tasks well. For word processing, certain computations, graphic arts and web surfing, the digital box on your desk is the best tool for the job. But the way your computer works, with its style of mathematics that relies on the binary code system of "on" and "off" 1s and 0s, isn't ideal for solving every problem.

That's why researchers such as Zoltán Toroczkai, professor in the Department of Physics and concurrent professor in the Department of Computer Science and Engineering at the University of Notre Dame, are interested in reviving analog computing at a time when digital computing has reached its maximum potential.

Toroczkai and collaborators have been working toward developing a novel mathematical approach that will help advance computation beyond the digital framework. His most recent paper, published in Nature Communications, describes a new mathematical, analog "solver" that can potentially find the best solution to NP-hard problems.

NP-hardness is a theory of computational complexity, with problems that are famous for their difficulty. When the number of variables is large, problems associated with scheduling, protein folding, bioinformatics, medical imaging and many other areas are nearly unsolvable with known methods. After testing their new method on a variety of NP-hard problems, the researchers concluded their solver has the potential to lead to better, and possibly faster, solutions than can be computed digitally.

Analog computers were used to predict tides from the early to mid-20th century, guide weapons on battleships and launch NASA's first rockets into space. They first used gears and vacuum tubes, and later, transistors, that could be configured to solve problems with a range of variables. They perform mathematical functions directly. For instance, to add 5 and 9, analog computers add voltages that correspond to those numbers, and then instantly obtain the correct answer. However, analog computers were cumbersome and prone to "noise" -- disturbances in the signals -- and were difficult to re-configure to solve different problems, so they fell out of favor.

Digital computers emerged after transistors and integrated circuits were reliably mass produced, and for many tasks they are accurate and sufficiently flexible. Computer algorithms, in the form of software, are sets of instructions that tell the computer hardware how to perform. Because the process is restricted to the use of 0s and 1s, this also makes their programming simpler, and allowed digital computing to dominate for nearly 70 years.

However, their restrictions may prevent digital computers from solving NP-hard problems with many variables. One such problem is the "Traveling Salesman" problem, in which a salesperson must start in one city and return to that city at the end of a trip, but in between, must travel to all the different cities on a list. What's the most efficient route among all the points? The problem becomes exponentially more challenging with the addition of more cities. The difficulty with such optimization problems, Toroczkai noted, is "while you can always come up with some answer, you cannot determine if it's optimal. Determining that there isn't a better solution is just as hard as the problem itself."

A challenge for analog computing rests with the design of continuous algorithms. Unlike digital computing, which has a long history in algorithm development, algorithms for analog computers lack a similar knowledge base and thus are very difficult to design. Toroczkai's approach is different from the types of algorithms for digital computers, in all aspects.

The next step is to design and build devices based on this approach, a process that will be tackled within Notre Dame's College of Engineering. The analog computers would be built for specific tasks, and not for everyday computing needs. This work is part of a larger-scale, multi-institutional effort, called Extremely Energy Efficient Collective Electronics (EXCEL), led by Notre Dame's Suman Datta, Freimann Chair of Engineering and professor of electrical engineering, in collaboration with Sharon Hu, professor of computer science and engineering.

"There are mostly engineering problems that need to be solved at this point, such as spurious capacities and better noise control, but it's going to get there," Toroczkai said. "Ideally I would like to see that you have this box on your desk that is your scheduler. And it is going to do much better of a job than your regular computer."

Find related stories on NSF's Critical Zone Observatories Sites. Find related stories on NSF's Long-Term Ecological Research Sites.

With fierce winds and flooding rains, hurricanes can be disasters for people -- and for ecosystems. These devastating storms have major effects on tropical forests, demolishing tree canopies and leaving behind debris that piles up in watershed streams and on forest floors.

Scientists at the National Science Foundation (NSF) co-located Luquillo Critical Zone Observatory (CZO) and Long-Term Ecological Research (LTER) sites in Puerto Rico spent the past year evaluating the impacts of Hurricane Maria, a powerful category 5 storm that struck Puerto Rico head-on in September 2017.

The researchers reported their results today at a press conference -- Puerto Rico one year later: Hurricane Maria's lasting footprint -- at the American Geophysical Union fall meeting in Washington, D.C.

Increased nitrate flowing downstream

After Maria, sensors measuring nitrate in streams at the NSF Luquillo CZO site showed a dramatic increase in how much of the nutrient was transported from mountain headwaters to the sea, according to biogeochemist William McDowell of the University of New Hampshire.

Nitrate is essential for plant growth. In large quantities, however, it can be harmful to coastal ecosystems. After major hurricanes like Maria and the tremendous changes they produce in vegetation, nitrate escapes from damaged forests and is flushed downstream, says McDowell.

"The implication of the loss of nitrogen from an ecosystem is uncertain," says McDowell, "but is likely to play a role in which trees grow back first." The downstream delivery of nitrate to coastal waters may also fuel algae blooms and, eventually, coastal dead zones.

Dead and broken trees

Based on data collected at the NSF Luquillo LTER site, Hurricane Maria killed twice as many trees as previous storms and tripled the number of broken trees, found ecologist Maria Uriarte of Columbia University. Palm trees were the exception; their sinewy stems bent in the wind and their fronds began to grow back almost immediately after the storm.

Future storms of Maria's strength could switch the dominant trees in Puerto Rico's forests from tall hardwoods to palms, Uriarte says, with consequences for whether forests take up more carbon or release carbon into the atmosphere.

Research offers new insights

McDowell and Uriarte will present their scientific findings on Friday, Dec. 14, in a conference session on "Tropical Forests in a Changing Environment."

Their studies at Luquillo address long-term climate patterns, disturbances such as hurricanes and landslides, and the legacies of land use history in forest and stream ecosystems. By understanding how nutrient cycles -- and plant and animal populations -- respond to natural and human disturbances, scientists can supply the information needed to model, manage and conserve tropical forest ecosystems.

Research at the NSF Luquillo CZO site focuses on physical and chemical processes in a mountain watershed. Scientists conducting research at the Luquillo CZO
study such subjects as mineral weathering, nutrient transport, and changing water, dust and sediment inputs to the ecosystem.

NSF Luquillo LTER research includes long-term observations of species and ecosystems; the connections between forest and stream ecology; and the ways mountains and precipitation interact. Experiments simulate the effects of hurricane intensity on forest and stream ecology.

EVANSTON, Ill. --- Most people have heard about antibiotic-resistant germs. But how about antibiotic-resistant dust?

A new Northwestern University study has found that an antimicrobial chemical called triclosan is abundant in dust -- and linked to changes in its genetic makeup. The result is dust with organisms that could cause an antibiotic-resistant infection.

"There is this conventional wisdom that says everything that's in dust is dead, but that's not actually the case. There are things living in there," said Northwestern's Erica Hartmann, who led the study. "Dust is the final resting place of everything that's been circulating in the air, so it can give us information about air quality."

The study was published today (Dec. 11) in the journal mSystems. Hartmann is an assistant professor of environmental engineering in Northwestern's McCormick School of Engineering. This work was done in partnership with the Biology and the Build Environmental Center at the University of Oregon.

Hartmann's study compared dust samples collected from 42 athletic facilities in the Pacific Northwest region. (Hartmann selected athletics facilities because people tend to make intimate contact with the floor, mats and equipment and use antimicrobial wipes to cleanse these areas before and after exercising.) Her team looked at the bacteria present in dust, specifically examining the bacteria's genes.

In dust with higher concentrations of triclosan, the researchers found higher abundances of genetic markers indicating antibiotic resistance. "Those genes do not code for resistance to triclosan," Hartmann clarified. "They code for resistance to medically relevant antibiotic drugs."

Up until 2017, manufacturers commonly added triclosan to antibacterial hand soaps and cleaning solutions. The Federal Drug Administration (FDA) banned triclosan in 2016, after discovering several dangerous side effects, including its potential to interfere with the human endocrine system. But even though it is no longer contained in hand soaps and the antibacterial wipes that people often use at the gym, triclosan is still present in toothpaste and many consumer products that are not labeled.

"There are many products with triclosan that are not labeled because they are within the purview of the EPA instead of the FDA," Hartmann said. "These things might include antimicrobial gym equipment, such as yoga mats and textiles."

Antibiotic resistance is an enormous threat to public health. According to the Centers for Disease Control and Prevention, nearly 25,000 people in the United States die each year from antibiotic-resistant infections. Even though triclosan has been banned, soaps and cleansers still contain other antimicrobial chemicals, including benzalkonium chloride, which Hartmann's team is now studying to see if it has a similar effect on dust.

Hartmann believes we could ease the problem of antibiotic-resistant bugs by letting go of antimicrobial products.

"The vast majority of microbes around us aren't bad and may even be good," she said. "Wipe down gym equipment with a towel. Wash your hands with plain soap and water. There is absolutely no reason to use antibacterial cleansers and hand soaps."

A simple online game can teach people to more accurately sort waste--with lasting results, a new UBC study has found.

Study participants who played the game developed by UBC researchers received immediate feedback on their sorting choices. The second time they played--when feedback was no longer provided--players still improved their average accuracy from 69 per cent to 84 per cent. Even when a week passed between games, players still improved their accuracy.

As part of the study, researchers also exposed students living in university residences to the game, then monitored their waste bins. They observed both a slight reduction in contamination--defined as the presence of items that shouldn't be in a particular bin--and an increase in compost weight.

"This immediate feedback increases recycling and composting accuracy over the longer term, both in the lab and in the field," said Jiaying Zhao, assistant professor in UBC's department of psychology and senior author of the study. "One of the big questions in psychology is how long do these effects last? Our biggest takeaways are the fact that immediate feedback works, and the effects last over time.

As solid waste increases rapidly, accurate sorting is becoming imperative in North American cities where the average person throws out 700-800 kilograms of solid waste each year. In the U.S., solid waste generation per capita increased 64 per cent between 1960 and 2013. One-third of landfill waste is organic and releases methane into atmosphere. Methane is 25 times more potent than carbon dioxide in creating conditions for climate change.

Yu Luo, the lead author of the paper, noted that social norms and the convenience of waste-sorting bins have encouraged people to try dealing with waste properly, but even when they make the effort, they make mistakes.

To correct these mistakes, Yu developed a simple sorting game. Four squares representing waste categories appear across the top of the screen: food scraps, recyclable containers, paper, and garbage. Then a picture of a waste item appears below. Players must decide where it goes. They are told whether they were right or wrong. If they were wrong, they are told which bin was the correct choice.

Research in cognitive psychology has shown that immediate feedback helps people learn and improves their task performance. The results of the experiment bear that out.

For the field experiment, researchers spent two weeks gathering baseline data on the weight and contamination rates of bins in three UBC student residences. Then, for six weeks, they promoted their game among residents of two buildings. Afterward, they spent three weeks gathering waste data and found that sorting had improved slightly in comparison with the third building.

Zhao is encouraged by results that suggest virtual sorting can help solve a real-world problem. UBC Campus and Community Planning has already adapted her group's research for a version of the game that is now part of orientation for first-year students, complete with leaderboards and prizes. Zhao sees no reason the idea couldn't be applied in all residential buildings--on campus and off.

The "gamification" of waste sorting could go a long way toward reducing contamination in waste streams and reducing the volume of solid waste.

(Philadelphia, PA) - During an ischemic attack, the heart is temporarily robbed of its blood supply. The aftermath is devastating: reduced heart contractility, heart cell death, and heart failure. Contributing to these detrimental changes is a signaling molecule, G protein-coupled receptor kinase 2 (GRK2), which following ischemia accumulates in mitochondria, the energy-producing powerhouses of cells. Now, a Temple-led research team shows for the first time that blocking GRK2 localization to mitochondria protects heart cells from ischemic injury and death, casting new light on GRK2 as a potential therapeutic target in post-injury heart failure.

"We knew from our previous work that GRK2 accumulates in mitochondria following ischemia, but the detrimental impacts of mitochondrial pooling of GRK2 were unclear," explained Walter J. Koch, PhD, W.W. Smith Endowed Chair in Cardiovascular Medicine, Professor and Chair of the Department of Pharmacology, and Director of the Center for Translational Medicine at the Lewis Katz School of Medicine at Temple University (LKSOM) and senior investigator on the new report. "We now show that the mitochondrial pool of GRK2 is not only damaging but also is associated with GRK2 phosphorylation and dysfunctional cardiac metabolism, leading to declines in heart cell function and increased heart cell death." The findings were published online December 11 in the journal Science Signaling.

Dr. Koch's team landed on their latest discovery after developing a knock-in mouse model, in which mice were made to express a form of GRK2 carrying a mutation at the Serine670 residue. The Serine670 alteration prevented GRK2 phosphorylation and ultimately its ability to localize to mitochondria. As a result, following ischemia-reperfusion injury, in which blood flow through the coronary artery was stopped briefly and then restarted, mimicking an ischemic attack in human patients, mutant mice showed no GRK2 accumulation in mitochondria. By contrast, wild-type mice had significant mitochondrial pooling of GRK2.

Investigation of heart tissue revealed that the knock-in mice sustained far less heart cell damage compared to wild-type animals. The size of ischemic injury was smaller in knock-in mice, and heart cell viability was increased. Mutant mice also had improved mitochondrial respiration and glucose oxidation rates.

"The lower levels of tissue injury observed in our mutated GRK2 mice were associated with better glucose metabolism, which is critical to attenuating oxidative stress and maintaining heart contractility and function," Dr. Koch said. The findings are consistent with his team's previous discovery that mitochondrial levels of GRK2 increase in response to oxidative stress and that mitochondrial GRK2 pooling is harmful to heart cells.

"Our findings [also] reinforce the link between cardiac injury and metabolism," explained first author Priscila Sato, PhD, Assistant Professor in the Department of Pharmacology and Physiology at Drexel University College of Medicine and formerly a researcher in Dr. Koch's laboratory at LKSOM. "We uncovered a novel role of GRK2 that helps us [better] understand the metabolic response to cardiac injury."

Dr. Koch and colleagues plan next to investigate the effects of blocking GRK2 phosphorylation in models of chronic heart failure. They also plan to search for proteins that might interact with GRK2 within the mitochondria to determine whether the detrimental effects of GRK2 are due to kinase activity or to a scaffolding effect that involves multiple proteins.

GRK2 levels are also known to be elevated in mice on high fat diets, suggesting that the molecule interacts with dietary factors. "In future studies we may be able to delineate how Western diet influences cardiac disease as it pertains to GRK2 signaling," Sato added.

Other researchers contributing to the study include: J. Kurt Chuprun, Meryl C. Woodall, Brett R Brown, Rajika Roy, Christopher J. Traynham, Jessica Ibetti, Anna M. Lucchese, Ancai Yuan, Konstantinos Drosatos, Doug G. Tilley, and Erhe Gao, from the Center for Translational Medicine and Department of Pharmacology at LKSOM; and Laurel A. Grisanti, the Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple, and the Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri-Columbia.

The research was supported by National Institutes of Health grants R37 HL061690, P01 HL075443, P01 HL091799, P01 HL091799, and HL130218; by Scientist Development Grants from the American Heart Association; and by the W.W. Smith Charitable Trust.

About Temple Health
Temple University Health System (TUHS) is a $2.1 billion academic health system dedicated to providing access to quality patient care and supporting excellence in medical education and research. The Health System consists of Temple University Hospital (TUH), ranked among the "Best Hospitals" in the region by U.S. News & World Report; TUH-Episcopal Campus; TUH-Northeastern Campus; Fox Chase Cancer Center, an NCI-designated comprehensive cancer center; Jeanes Hospital, a community-based hospital offering medical, surgical and emergency services; Temple Transport Team, a ground and air-ambulance company; and Temple Physicians, Inc., a network of community-based specialty and primary-care physician practices. TUHS is affiliated with the Lewis Katz School of Medicine at Temple University, and Temple University Physicians, which is Temple Health's physician practice plan comprised of more than 500 full-time and part-time academic physicians in 20 clinical departments.

The Lewis Katz School of Medicine (LKSOM), established in 1901, is one of the nation's leading medical schools. Each year, the School of Medicine educates more than 800 medical students and approximately 240 graduate students. Based on its level of funding from the National Institutes of Health, the Katz School of Medicine is the second-highest ranked medical school in Philadelphia and the third-highest in the Commonwealth of Pennsylvania. According to U.S. News & World Report, LKSOM is among the top 10 most applied-to medical schools in the nation.

Temple Health refers to the health, education and research activities carried out by the affiliates of Temple University Health System (TUHS) and by the Katz School of Medicine. TUHS neither provides nor controls the provision of health care. All health care is provided by its member organizations or independent health care providers affiliated with TUHS member organizations. Each TUHS member organization is owned and operated pursuant to its governing documents.

Electronic prescribing is becoming widespread. All states allow it, some states require it, and many institutions now mandate electronic prescribing. Many electronic prescribing systems use computerized decision support algorithms that give automated warnings or alerts at the time of prescribing if a potential prescribing error is identified -- for example, regarding dosing or contraindications. Some studies suggest that electronic prescribing alerts may reduce prescribing errors and can be clinically useful, but others caution that the warnings may have substantial limitations and that clinicians often consider them clinically irrelevant. Harmful unintended consequences of such prescribing alerts have been described. Despite this topic's importance, few studies have examined the accuracy of automated prescribing warnings in electronic prescribing systems; to our knowledge no study has focused primarily on the accuracy of systems regarding prescribing of psychotropic medications. To examine this issue, we surveyed members of the American Society for Clinical Psychopharmacology (ASCP) regarding automated warnings generated by electronic prescribing systems.

The results indicated that a substantial proportion of prescribing clinicians with an interest in psychopharmacology believe that their electronic prescribing system has provided incorrect prescribing warnings. It is particularly problematic that some warnings do not reflect product labeling information - for example, regarding maximum dose or contraindications. Such errors potentially have profound consequences. For example, the erroneous warning that SSRIs and aripiprazole are contraindicated for children and adolescents may cause inadequate treatment of potentially life-threatening conditions in this age group. It is also concerning that most respondents reported being unable to alert the system about the inaccuracy of a prescribing warning. Nonetheless, automated electronic prescribing alerts are potentially useful; a limitation of our survey is that it did not assess the perceived usefulness of alerts or the balance of perceived benefits versus perceived risks. Other limitations include the low survey response rate and the small number of responses for some questions. We also do not know whether all alerts considered erroneous were actually erroneous. Additional studies of this topic are needed, especially given increasing use of electronic prescribing and potentially detrimental clinical consequences of inaccurate prescribing warnings.

Research in recent years has linked a person's physical or social environment to their well-being. Stress wears down the body and compromises the immune system, leaving a person more vulnerable to illnesses and other conditions. Various stressors, from family adversity to air pollution, can lead to inflammation, diabetes and heart disease.

But scientists do not fully understand how the association between stress and health plays out at the cellular level. A new study examines one key stress-inducing circumstance -- the effects of social hierarchy -- and how cells respond to the hormones that are released in response to that stress. They found that social status determined how individual macaques responded to a key stress hormone, glucocorticoid.

"The goal is to understand the mechanisms through which social experiences or environment 'get under the skin,' so to speak, to affect health and survival," said the study's lead author, Noah Snyder-Mackler, a University of Washington assistant professor of psychology.

The study conducted in collaboration with researchers at Duke University, the University of Montreal and the Yerkes National Primate Research Center, is published Dec. 11 in the Proceedings of the National Academy of Sciences.

For this research, Snyder-Mackler and the team turned to a nonhuman social primate: the rhesus macaque. Scientists mixed up existing social groupings of nearly four dozen macaques, observed behaviors among the new groups, and analyzed blood samples to determine the cellular effects of the new social order. The team specifically measured effects on the peripheral immune system, which are immune cells that patrol other systems of the body, such as muscles.

Macaques were a suitable subject for this research, Snyder-Mackler explained, because they are relatively close cousins of humans but lack certain cultural or societal factors, such as substance use or access to medical care, which can complicate any corresponding study of human health.

The new study extends Snyder-Mackler's research from his postdoctoral work at Duke University, which in a 2016 study reported that social status had a direct effect on immune systems. The current study altered the groupings of monkeys to see how cells responded to what would happen in a short-term stress situation.

In humans and other primates, social status has been linked to health and quality of life. Lower social status can mean less social and community support, and fewer buffers against stress or adverse circumstances. In animals, that equates to fewer allies and greater harassment from peers, while in humans, lower status is often tied to struggles with income, employment and relationship stability.

Organizing the macaques into nine new groups in effect created a new social hierarchy, the authors wrote, whereby the order in which each monkey was introduced also determined its status. The first in the group became the most dominant and held the highest rank, while the last to join the group typically held the lowest status.

After each group's hierarchy was established and the team could observe the macaques' behavior, the researchers then took blood samples and treated them with a synthetic glucocorticoid -- which mimicked the macaques' natural, primary stress hormone. In both macaques and people, glucocorticoid hormones are activated to mobilize resources during times of heightened stress; the ways that cells respond to a surge in stress hormones can indicate whether the body can appropriately respond to the stressor, or whether the stress pathway is chronically activated, which wears down the body and leaves it more susceptible to illness.

By using the synthetic-treated blood samples to simulate what happens inside the macaques during acute stress, the researchers could show how the glucocorticoid hormone could affect cellular behavior in different macaques -- particularly whether macaques responded productively to the stress hormone, or had been worn down by it and no longer responded appropriately. In this experiment, the cells of the lower-status macaques were less able than those of the higher-status animals to respond productively to the glucocorticoid. One explanation for this lack of a response was found within the macaque immune cells' genetic information. By measuring chromatin accessibility -- how the DNA is packaged in the cell -- they found that low-status females had immune cells that were less accessible to the signal from the glucocorticoids.

In humans, stressful or traumatic situations such as losing a job, caring for a chronically ill child or grieving the death of a loved one have been linked to glucocorticoid resistance -- the physical toll, at the cellular level, of stress on the human body. Snyder-Mackler's work suggests one possible mechanism, namely altered chromatin accessibility, that may underlie glucocorticoid resistance in low-status individuals.

"Given the shared biology and evolutionary history between monkeys and humans, these findings help us better understand how social status can affect humans," Snyder-Mackler said.

Further research is needed, he added, to identify the magnitude of the effects of stress, as ignited by a change in social status, and what buffers might protect individuals from those impacts. Not all individuals respond similarly to the same stress; some are more resilient -- or susceptible -- to the same stressor.

"We know that social adversity early in life can have far-reaching effects that extend into adulthood. The questions are, when do these events have to occur, how severe do they have to be, and are they reversible or even preventable?" Snyder-Mackler said.

People with diabetes and followers of diets based on the glycemic index (GI) can enjoy dried fruits knowing they do not cause a blood sugar spike compared to starchy foods such as white bread, suggests a study published in the journal Nutrition and Diabetes.

The results of the study also suggest there's potential for food manufacturers to develop low GI foods with reformulations that include dried fruit, say Dr. John Sievenpiper of Toronto's St. Michael's Hospital and researcher Cyril Kendall of the hospital's Clinical Nutrition and Risk Factor Modi?cation Centre.

The glycemic index was developed by Dr. David Jenkins of St. Michael's Hospital in the early 1980s as a way of explaining how different carbohydrates affect blood glucose and to find out which foods were best for people with diabetes. Foods high on the GI index -- such as white bread, most breakfast cereals, potatoes and rice -- produce a spike in blood glucose and insulin, while the carbohydrates in low GI foods -- including pasta, beans, lentils and certain whole grains such as barley and oats - are broken down more slowly, and cause more moderate increases in blood glucose and insulin.

This study compared the glycemic response of four dried fruits -- dates, apricots, raisins and sultanas -- versus white bread in 10 healthy participants and found the fruit had a lower GI and could lower the glycemic response of white bread through displacement of half of the available carbohydrate.

"People often worry about sources of sugar and fruits being one of them, but most fruit -- in particular tender fruit -- have a low glycemic index and what we're showing here is dried fruit also have a lower glycemic index, so they don't raise your blood sugar very much," said Dr. Sievenpiper.

"This study finds people can use dried fruits as a low glycemic index food source to replace higher glycemic index foods, so as a snack food, for example. Dried fruit is going to be preferred to a grain-based cracker or snack."

Dr. Sievenpiper said longer and larger randomized trials will be needed to confirm whether dried fruit can contribute to sustainable improvements in glycemic control, and whether other dried fruits have a similar GI.

SALT LAKE CITY, UTAH, USA and LEIDEN, THE NETHERLANDS - An international team of researchers led by Huntsman Cancer Institute (HCI) at the University of Utah (U of U) has developed, calibrated, and validated a novel tool for identifying the genetic changes in Lynch syndrome genes that are likely to be responsible for causing symptoms of the disease. The results were published this week in the journal Genetics in Medicine.

Lynch syndrome is a hereditary condition that results in higher rates of colon, endometrial, and other cancers. If unmanaged, individuals with Lynch syndrome have a 75 percent lifetime risk of developing colorectal cancer. It is believed that approximately five percent of all colorectal cancer cases are associated with this syndrome.

Millions of distinct changes are possible in genes that control health, and it is a massive undertaking to identify which specific changes are associated with developing disease. Some genetic changes are believed to have no impact at all, while others carry significant risk.

Researchers at Huntsman Cancer Institute work to understand and classify which gene changes are likeliest to cause disease, as well as to identify appropriate strategies to help manage disease risk.

This groundbreaking study was led by Sean Tavtigian, PhD, a cancer researcher at HCI and professor of oncological sciences at the U of U. The work was built on a decade-long international collaboration. "Correctly identifying which of the genetic changes we observe actually result in disease is fundamentally important in clinical care," said Tavtigian. "Having clarity on this issue has the potential to add years to patients' lives, reduce anxiety about disease risk, and use health care dollars more efficiently."

The team used a laboratory test previously developed by the group of Niels de Wind, PhD, associate professor of human genetics at the Leiden University Medical Center in The Netherlands, to characterize genetic changes associated with disease risk. The lab test, called the Cell-free in vitro MMR Activity (CIMRA) assay, improves classification of variants of uncertain significance in Lynch syndrome. "The test is rapid and accurate," said de Wind. In the current study, the test was thoroughly calibrated and validated, such that its results could now be integrated with computer-based modeling and clinical data. As a result, this study provides an analytical tool suitable for clinical use to assess the potential of changes in Lynch syndrome genes to cause disease.

"A key point is that we believe the accuracy of the tool combining the CIMRA test with the previously published computational analysis to be about 97 percent, making it appropriate for clinical use," said Tavtigian. de Wind added that the work "represents a new pinnacle in the classification of genetic variation."

The authors believe that routine utilization of their methods will dramatically increase the rate of risk classification for genetic changes that previously were poorly understood. Moreover, this calibration strategy provides a template for the development, validation, and calibration of reliable strategies for the diagnostic assessment of other hereditary cancer predisposition syndromes and genetic disorders.

Brian Wainger, MD, PhD, of the Healey Center for ALS at Massachusetts General Hospital (MGH) presented initial, top-level results of a recently completed phase 2 clinical trial of ezogabine (also called retigabine) on December 9 at the Motor Neurone Disease Association annual meeting in Glasgow, Scotland. The trial met its primary goal of measuring a reduction in motor neuron excitability in people with amyotrophic lateral sclerosis (ALS) following treatment.

ALS - also called Lou Gehrig's disease or motor neuron disease - is a progressive neurodegenerative disorder that leads to the death of neurons in the brain and spinal cord. There are only three drugs with limited effects approved in the United States for treating ALS, and new therapies that substantially prolong lifespan are urgently needed. An essential step toward developing new treatment avenues is unraveling the biological processes that go awry in this disorder and identifying novel molecular targets for drug intervention.

Ezogabine has a unique mechanism of action of activating the Kv7 or KCNQ family of voltage-gated potassium channels in cell membranes and can calm the excitability of nerve cells that cause seizures. Similar "hyperexcitability" in motor neurons may play a role in ALS, and the study - conducted by investigators from the MGH Neurological Clinical Research Institute (NCRI) at sites of the Northeast ALS Consortium - evaluated ezogabine's potential in the context of ALS. The investigators used transcranial magnetic stimulation and threshold tracking nerve conduction studies to measure the effects of ezogabine on upper and lower motor neuron excitability in 65 people with ALS and found that treatment did reduce motor neuron excitability. The study was not powered to assess clinical outcomes.

This trial was supported by The ALS Association, GlaxoSmithKline, the Harvard Stem Cell Institute (HSCI) and the MGH NCRI. Preclinical studies in human induced pluripotent stem cells (iPSCs) leading up to the clinical trial, performed at Boston Children's Hospital and Harvard University, were supported by The ALS Association, HSCI, the National Institute of Neurological Disorders and Stroke, the New York Stem Cell Foundation and Target ALS. Wainger is a New York Stem Cell Foundation - Robertson Investigator.

"This novel study provides us with a better understanding of neuron hyperexcitability, an important ALS disease pathway, and we are thrilled to be a part of such a powerful collaborative team," says Calaneet Balas, president and CEO of The ALS Association.

Lucie Bruijn, PhD, MBA, chief scientist, The ALS Association, adds, "This is the first clinical trial for ALS that was designed using data based on an iPSC model of ALS and was possible in part due to the availability of a biomarker in people living with disease that measures excitability of motor neurons, also characterized in the iPSC model."

Consumers paid on average £75 more in the year after the EU referendum for gas and electricity, according to research by UCL.

A hard Brexit could lead to a further average rise of £61 per year in the event of further devaluation of sterling to pound-euro parity.

The UCL researchers found that energy bills increased overall by £2 billion in 2017 due to the lower value of sterling relative to the euro and US dollar. The average wholesale prices of electricity and gas rose by 18 per cent and 16 per cent respectively in the year after the referendum, translating into a £35 increase for electricity and £40 for gas.

Lead author Dr Giorgio Castagneto Gissey (UCL Bartlett School of Environment, Energy & Resources), said: "We know that exchange rates fell after the EU referendum but we can now look at the effect this had on wholesale and consumer energy prices.

"The exchange rate depreciation plus the fact that energy prices are now much more volatile means consumers have been paying more and are facing even higher bills over the next several months."

The wholesale gas price makes up 39 per cent of the price paid by consumers, so the 16 per cent increase resulted in a six per cent (£40) increase in retail prices. The variability of wholesale gas prices increased by 60 per cent in the year after the vote.

Co-author Professor Michael Grubb (UCL Bartlett School of Environment, Energy & Resources) said: "Forecasts always carry some uncertainty, but this research pinpoints historical fact: the referendum result, through its impact on exchange rates, has been the principal factor driving up UK household energy prices over the past two years."

The Government passed a law in July giving Ofgem the power to set a price cap, and subsequently a cap said to save the average household £75 a year on standard tariffs has been proposed.

The predicted price rise of a further £61 resulting from a hard Brexit breaks down into £29 from electricity and £32 for gas. This corresponds to a predicted extra £1.5 billion added to consumers' annual energy bill from the end of March 2019 to the end of March 2020.

The academics analysed the behaviour of the wholesale electricity price in the UK alongside the sterling to euro exchange rate between 2012 and 2017, finding that as the exchange rate fell dramatically after the EU referendum the electricity price increased over the subsequent year, directly reflecting the resulting higher cost of energy imports.

The prediction following a hard Brexit is based on an assumption of a further depreciation of sterling to sterling-euro parity, with a 12 per cent drop from the exchange rate of 1.14 on the 3 November 2018. The change in annual bills was calculated assuming everything else is held constant between 29 March 2019 and 29 March 2020.

The team behind the overall report used several data types; electricity generation and thermal efficiencies of fuel-intensive plants were used to calculate the shares at margin, with fuel and imbalance prices and volumes used to model electricity prices and derive pass-through rates.

For the overall report, the researchers aimed to understand the principal determinants of electricity wholesale prices in the UK and some major European markets. Those considered additionally were Germany, France, Italy, Spain, the Netherlands and Norway from 2012 to 2017. The report found Great Britain to be among the most cost-reflective of a sample of European electricity wholesale markets.

Characters in the Game of Thrones TV series are more likely to die if they do not switch allegiance, and are male, according to an article published in the open access journal Injury Epidemiology.

Researchers at Macquarie University, Australia, evaluated the deaths of all important Game of Thrones characters across seven seasons of the show and found that characters were more likely to survive if they switched allegiances, such as Tyrion Lannister who switches allegiances between the houses Lannister and Targaryen. The risk of death was also greater for characters that were 'lowborn' (not a Lord or Lady), compared to those that were 'highborn'.

Dr Reidar Lystad, injury epidemiologist at the Australian Institute of Health Innovation and corresponding author of the study, said: "The risk of death is high among characters in Game of Thrones. By the end of the seventh season, more than half of the characters had died - 186 out of the 330 characters we included in this study - with violent deaths being the most common by far."

Dr Lystad added: "While these findings may not be surprising for regular viewers, we have identified several factors that may be associated with better or worse survival, which may help us to speculate about who will prevail in the final season."

The authors found that the majority of deaths occurred in Westeros (80.1%), and the most common place of death was in the home. The most common causes of death were injuries (73.7%), and particularly wounds of the head and neck, including 13 decapitations. Only two deaths from natural causes occurred across the seven seasons of the show: Maester Aemon and Old Nan, who both died of old age. The remainder of deaths were from burns (11.8%) or poisonings (4.8%). The most common circumstances of deaths were assault (63.0%), operations of war (24.4%), and legal executions (5.4%).

The probability of dying within the first hour after first appearing on screen was around 14%. The survival time of characters ranged from 11 seconds to 57 hours and 15 minutes. The median survival time was estimated to be 28 hours and 48 minutes.

The researchers collected data on mortality and survival of 330 characters from all 67 episodes from seasons one to seven of Game of Thrones. They recorded data on the sociodemographic status of the characters, including their sex, social status, type of occupation, religious affiliation, and allegiance, alongside their survival time, and the circumstances of their death. This information was used to quantify predictors of death. The researchers crosschecked all of their data with Internet Movie Database (IMDb) and Game of Thrones Wiki.

University of Sydney authors who led the research said the Mamil study was prompted by media attention given to depicting and satirising this group and the importance of physical activity for preventing lifestyle diseases like cardiovascular disease.

"The origins of the Mamil species are unclear, but the first descriptions, from around 2010, were characterised by middle-aged men wishing to break free from midlife crises and to obtain a new lease on life by purchasing an extravagant, slick, highly accessorised bicycle with a design fit for the Champs-Élysées," say the authors in the MJA report.

Key findings

The proportion of middle aged men aged 45-65 years who cycled at least once in the previous year nearly doubled from 11 percent (2002-04) to 20.8 percent (2016)

The proportion of middle aged men aged 45-65 years who cycled at least once a week in the previous year more than doubled from 6.2 percent (2002-04) to 13.2 percent (2016)

The proportion of middle aged men aged 40-59 years who cycle to work hasn't changed between 2006 (1.1 percent) and 2016 (1.3 percent)

Previously published data show the proportion of middle-aged men from high income suburbs who cycled at least weekly more than doubled over a 14-year study period, from 7.5 percent (2002-04) to 17.4 percent (2016).

Concurrent trends in newspaper reporting on Mamils are correlated with data showing the increasing prevalence of weekend cycling among affluent, middle aged men.

Media tracking data reveals a marked increase in media reporting on Mamils since 2010, with a peak in 2014. Overall, there were about 150 references to 'Mamils' each year in major print media, mostly in the United Kingdom (60 percent of mentions) or Australia (31 percent of mentions).

Lead author Professor Adrian Bauman of the University of Sydney said: "We found that cycling by middle-aged men has increased since 2002-04, supporting reports of the growth of the Mamil species.

"However, most are weekend superheroes who do not cycle to work during the week.

"The habitats of Mamils are affluent urban environments, often near the water, where Mamils meet in groups to channel their inner Cadel Evans."

Chestnut Hill, Mass. (12/7/2018) - Like so many targets of scientific inquiry, the class of material referred to as the kagome magnet has proven to be a source of both frustration and amazement. Further revealing the quantum properties of the kagome magnet is seen as one of the primary challenges in fundamental physics - to both theorists and experimentalists.

An unusual underlying geometry of the atomic arrangement is central to the value of these materials. Kagome lattices are described as intersecting webs of "corner-sharing triangles" and are prized for the unique behavior of the traversing electrons, fertile ground for the study of quantum electronic states described as frustrated, correlated and topological.

A recent study by an international group of researchers, published in the journal Nature, found the kagome ferromagnet Fe3Sn2 exhibits an electronic state that couples unusually strongly to an applied magnetic field that can be rotated to point in any direction of a 3-dimensional space, revealing in quantum scale a "giant" magnetization-driven electronic energy shift taking place within the material.

That energy shift sheds new light on the presence of spin-orbit coupling and topological spin textures in kagome lattices, where magnetic and electronic structures are entangled and produce unusual - often previously unknown - spin-orbit activity, said Boston College Professor of Physics Ziqiang Wang, a co-author of the report, titled "Giant and anisotropic spin-orbit tunability in a strongly correlated kagome magnet."

"We found out two things. The first one is that the electronic state of Fe3Sn2 is nematic, a state that spontaneously breaks the rotation symmetry. The electrons behave as a liquid crystal inside this magnet, presumably due to the strong electron-electron interaction," said Wang. "The second thing we found is you can manipulate and make big changes to the electron energy structure through tuning the magnetic structure by applying a magnetic field."

Wang, a theoretical physicist, and graduate student Kun Jiang, PhD, who have been studying novel quantum electronic states resulting from the interplay of electron-electron interaction, geometrical frustration, and topological band structures, joined experimentalist colleagues who first noted the unusual electronic activity as they studied the material using scanning tunneling microscopy.

The team - which included researchers from BC, Princeton University, Chinese Academy of Sciences, Renmin University, and Peking University - used STM and vector-magnetic-field tools to identify the spin-orbit coupled electronic properties of the kagome ferromagnet and explored the exotic phenomena within it, while performing modeling and calculations to provide theoretical interpretation and understanding of the observed phenomena.

"What our colleagues found is that by changing the direction of the magnetic field, they saw changes in the electronic states that are anomalously large," said Wang. "The shifts of the bands - there are band gaps, forbidden regions in quantum mechanics where electrons cannot reside - those regions can be tuned enormously by the applied magnetic field."

The "band shift" is a change in electronic band structure, said Wang. It expands and narrows the band gap depending on the magnetic field directions. The kagome ferromagnet showed a shift approximately 150 times larger than ordinary materials.

Probing the interference patterns of the electron's quantum mechanical wave functions revealed consistent spontaneous nematicity -- an indication of important electron correlation that causes the rotation symmetry-breaking of the electronic state in the material.

These spin-driven giant electronic responses indicated the possibility of an underlying correlated magnetic topological phase, the researchers reported. The tunability of the kagome magnet revealed a strong interplay between an externally applied magnetic field and nematicity, providing new ways of controlling spin-orbit properties and exploring emergent phenomena in topological or quantum materials, the team wrote.

The giant magnetic field tunability of the electrical properties may one day lead to potential applications in electronic devices such as memory and information storage and sensing technologies, said Wang.

"What's exciting in these results is the potential of realizing something useful," said Wang. "This is coming from very fundamental physics, but it may one day connect to applications. We don't understand everything, but we now know this is a material that contains all these important ingredients."