Non-invasive nerve stimulation boosts learning of foreign language sounds

UNIVERSITY OF PITTSBURGH

  

IMAGE: ILLUSTRATION OF THE VAGUS NERVE view more 

CREDIT: KENNETH PROBST/UCSF

PITTSBURGH, Aug. 6, 2020 - New research by neuroscientists at the University of Pittsburgh and University of California San Francisco (UCSF) revealed that a simple, earbud-like device developed at UCSF that imperceptibly stimulates a key nerve leading to the brain could significantly improve the wearer's ability to learn the sounds of a new language. This device may have wide-ranging applications for boosting other kinds of learning as well.

Mandarin Chinese is considered one of the hardest languages for native English speakers to learn, in part because the language -- like many others around the world -- uses distinctive changes in pitch, called "tones," to change the meaning of words that otherwise sound the same. In the new study, published today in npj Science of Learning (a Nature partner journal), researchers significantly improved the ability of native English speakers to distinguish between Mandarin tones by using precisely timed, non-invasive stimulation of the vagus nerve -- the longest of the 12 cranial nerves that connect the brain to the rest of the body. What's more, vagus nerve stimulation allowed research participants to pick up some Mandarin tones twice as quickly.

"Showing that non-invasive peripheral nerve stimulation can make language learning easier potentially opens the door to improving cognitive performance across a wide range of domains," said lead author Fernando Llanos, Ph.D., a postdoctoral researcher in Pitt's Sound Brain Lab.

"This is one of the first demonstrations that non-invasive vagus nerve stimulation can enhance a complex cognitive skill like language learning in healthy people," said Matthew Leonard, Ph.D., an assistant professor, Department of Neurological Surgery, UCSF Weill Institute for Neurosciences, whose team developed the nerve stimulation device. Leonard is a senior author of the new study, alongside Bharath Chandrasekaran, Ph.D., professor and vice chair of research, Department of Communication Science and Disorders, Pitt School of Health and Rehabilitation Sciences, and director of the Sound Brain Lab.

Researchers used a non-invasive technique called transcutaneous vagus nerve stimulation (tVNS), in which a small stimulator is placed in the outer ear and can activate the vagus nerve using unnoticeable electrical pulses to stimulate one of the nerve's nearby branches.

For their study, the researchers recruited 36 native English-speaking adults and trained them to identify the four tones of Mandarin Chinese in examples of natural speech, using a set of tasks developed in the Sound Brain Lab to study the neurobiology of language learning.

Participants who received imperceptible tVNS paired with two Mandarin tones that are typically easier for English speakers to tell apart showed quick improvements in learning to distinguish these tones. By the end of the training, those participants were 13% better on average at classifying tones and reached peak performance twice as quickly as control participants who wore the tVNS device but never received stimulation.

"There's a general feeling that people can't learn the sound patterns of a new language in adulthood, but our work historically has shown that's not true for everyone," Chandrasekaran said. "In this study, we are seeing that tVNS reduces those individual differences more than any other intervention I've seen."

"This approach may be leveling the playing field of natural variability in language learning ability," added Leonard. "In general, people tend to get discouraged by how hard language learning can be, but if you could give someone 13% to 15% better results after their first session, maybe they'd be more likely to want to continue."

The researchers now are testing whether longer training sessions with tVNS can impact participants' ability to learn to discriminate two tones that are harder for English speakers to differentiate, which was not significantly improved in the current study.

Stimulation of the vagus nerve has been used to treat epilepsy for decades and has recently been linked to benefits for a wide range of issues ranging from depression to inflammatory disease, though exactly how these benefits are conferred remains unclear. But most of these findings have used invasive forms of stimulation involving an impulse generator implanted in the chest. By contrast, the ability to evoke significant boosts to learning using simple, non-invasive vagus nerve stimulation could lead to significantly cheaper and safer clinical and commercial applications.

The researchers suspect tVNS boosts learning by broadly enhancing neurotransmitter signaling across wide swaths of the brain to temporarily boost attention to the auditory stimulus being presented and promote long-term learning, though more research is needed to verify this mechanism.

"We're showing robust learning effects in a completely non-invasive and safe way, which potentially makes the technology scalable to a broader array of consumer and medical applications, such as rehabilitation after stroke," Chandrasekaran said. "Our next step is to understand the underlying neural mechanism and establish the ideal set of stimulation parameters that could maximize brain plasticity. We view tVNS as a potent tool that could enhance rehabilitation in individuals with brain damage."

Additional authors are Jacie McHaney, of Pitt; and William Schuerman, Ph.D., and Han Yi, Ph.D., both of UCSF.

The research was funded by the Defense Advanced Research Projects Agency Targeted Neuroplasticity Program (contract number: N66001-17-2-4008).

To read this release online or share it, visit https://www.upmc.com/media/news/080620-mandarin-vagus-stim [when embargo lifts].

About the University of Pittsburgh School of Health and Rehabilitation Sciences

SHRS is an international leader in rehabilitation and disabilities education, research and community service. SHRS's mission is to improve the lives and independence of all people with a focus on people at risk for, or have chronic conditions or disabilities, and those who have traditionally been underserved and underrepresented. SHRS is home to several nationally ranked programs and world-renowned faculty and clinicians within all areas of the health sciences. For more information, visit http://www.shrs.pitt.edu.

About UCSF

The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes UCSF Health, which comprises three top-ranked hospitals, as well as affiliations throughout the Bay Area. Learn more at ucsf.edu, or see our Fact Sheet.

First food-grade intermediate wheatgrass released

AMERICAN SOCIETY OF AGRONOMY

IMAGE: UMN KERNZA RESEARCHER PRABIN BAJGAIN EVALUATING INTERMEDIATE WHEATGRASS IN SELECTION NURSERY AT ST. PAUL, MN BEFORE HARVEST IN FALL 2019. view more 

CREDIT: PRABIN BAJGAINCompared to annual crops, perennial crops provide sustainable environmental benefits such as reduced soil and water erosion, reduced soil nitrate leaching, and increased carbon sequestration. Inclusion of sustainable cropping systems into mainstream agriculture has been a challenge given the lack of food-grade perennial grain cultivars.

In an article recently published in the Journal of Plant Registrations , a publication of the Crop Science Society of America, University of Minnesota researchers report the release of the first commercially available intermediate wheatgrass (IWG) cultivar. IWG is a cool-season perennial grain crop domesticated primarily for food use while maintaining the ecological benefits it offers.

The cultivar, named 'MN-Clearwater,' produces 696 kg ha-1 (621 lb ac-1) of grain on average with the first two years; it produces its highest grain yields under Minnesota conditions. It is relatively short at 113 cm and has minimal lodging with trace disease levels. MN-Clearwater is expected to perform well in US Upper Midwest, southern regions of Canada, and the US Northeast.

As the first IWG cultivar released for sale under the Kernza® trade name, we expect MN-Clearwater to be a cornerstone resource for the IWG research community as well as for interested growers, food processors, and commercial partners.

Adapted from Bajgain, P, Zhang, X, Jungers, JM, et al. 'MN-Clearwater', the first food-grade intermediate wheatgrass (Kernza perennial grain) cultivar. J. Plant Regist. 2020; 1- 10.

DNA from an ancient, unidentified ancestor was passed down to humans living today

New algorithm suggests that early humans and related species interbred early and often

PLOS

 

A new analysis of ancient genomes suggests that different branches of the human family tree interbred multiple times, and that some humans carry DNA from an archaic, unknown ancestor. Melissa Hubisz and Amy Williams of Cornell University and Adam Siepel of Cold Spring Harbor Laboratory report these findings in a study published 6th August in PLOS Genetics.

Roughly 50,000 years ago, a group of humans migrated out of Africa and interbred with Neanderthals in Eurasia. But that's not the only time that our ancient human ancestors and their relatives swapped DNA. The sequencing of genomes from Neanderthals and a less well-known ancient group, the Denisovans, has yielded many new insights into these interbreeding events and into the movement of ancient human populations. In the new paper, the researchers developed an algorithm for analyzing genomes that can identify segments of DNA that came from other species, even if that gene flow occurred thousands of years ago and came from an unknown source. They used the algorithm to look at genomes from two Neanderthals, a Denisovan and two African humans. The researchers found evidence that 3 percent of the Neanderthal genome came from ancient humans, and estimate that the interbreeding occurred between 200,000 and 300,000 years ago. Furthermore, 1 percent of the Denisovan genome likely came from an unknown and more distant relative, possibly Homo erectus, and about 15% of these "super-archaic" regions may have been passed down to modern humans who are alive today.

The new findings confirm previously reported cases of gene flow between ancient humans and their relatives, and also point to new instances of interbreeding. Given the number of these events, the researchers say that genetic exchange was likely whenever two groups overlapped in time and space. Their new algorithm solves the challenging problem of identifying tiny remnants of gene flow that occurred hundreds of thousands of years ago, when only a handful of ancient genomes are available. This algorithm may also be useful for studying gene flow in other species where interbreeding occurred, such as in wolves and dogs.

"What I think is exciting about this work is that it demonstrates what you can learn about deep human history by jointly reconstructing the full evolutionary history of a collection of sequences from both modern humans and archaic hominins," said author Adam Siepel. "This new algorithm that Melissa has developed, ARGweaver-D, is able to reach back further in time than any other computational method I've seen. It seems to be especially powerful for detecting ancient introgression."

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Peer-reviewed / Observational study / People

In your coverage please use this URL to provide access to the freely available article in PLOS Genetics:

http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1008895

Citation: Hubisz MJ, Williams AL, Siepel A (2020) Mapping gene flow between ancient hominins through demography-aware inference of the ancestral recombination graph. PLoS Genet 16(8): e1008895. https://doi.org/10.1371/journal.pgen.1008895

Funding: MJH and AS were supported by US National Institutes of Health grant R35-GM127070 (to AS) (https://www.nih.gov), and MJH was additionally supported by National Science Foundation GRFP DGE-1650441 (https://www.nsf.gov). ALW was supported by an Alfred P. Sloan Research Fellowship (https://sloan.org/fellowships/) and a seed grant from Nancy and Peter Meinig. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number ACI-1548562 (https://www.nsf.gov). The content is solely the responsibility of the authors and does not necessarily represent the official views of the US National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Children's pester power a future target for interventions

Children's influence on their homes may be an underdeveloped potential target for future interventions, according to a new study in the Journal of Nutrition Education and Behavior

ELSEVIER

 

AUDIO: LEAD INVESTIGATOR TAREN SWINDLE, PHD, DISCUSSES A NEW STUDY THAT HIGHLIGHTS HOW CHILDREN'S PESTER POWER MAY INFLUENCE FOOD CONSUMPTION AND HABITS AT HOME. view more 

CREDIT: JOURNAL OF NUTRITION EDUCATION AND BEHAVIOR

Philadelphia, August 6, 2020 - Children's pester power may contribute to improvements in their family's food environments. A new study in the Journal of Nutrition Education and Behavior, published by Elsevier, highlights the potential for children to influence food consumption and habits at home.

Researchers from the University of Arkansas for Medical Sciences and Louisiana Tech University studied classrooms that delivered weekly Together, We Inspire Healthy Eating (WISE) lessons at seven Head Start sites across two states in the southern United States. The study demonstrated that children's pester power explained a significant portion of the variance in the residual change of children's dietary intake and parenting practices after one school year of exposure to the WISE intervention.

"The more pester power that parents were exposed to from their children, the greater we saw changes in the desired direction for intake of fruits and vegetables and also supportive parenting practices," said lead study author Taren Swindle, PhD, Department of Family and Preventive Medicine, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA. "It means that children's influence on their homes may be an underdeveloped potential target for future interventions."

The pester power of children is well documented in marketing and advertising research and is increasingly being considered in regard to the nutritional habits and obesogenic environments of children. Future studies can provide insight into which components of educational programs specifically predict successful pester power.

"I like to think of this as hypothesis-generating work. It suggests a really promising area for future exploration," Prof. Swindle said.

UK 

Large proportion of NHS workers may have already had COVID-19

Peer reviewed - survey - people

UNIVERSITY OF EAST ANGLIA

 

A large proportion of UK healthcare workers may already have been infected  Covid-19, according to new research led by the University of East Anglia in collaboration with University College London.

In May, Public Health England added a new loss of taste or smell (anosmia) to the list of symptoms for Covid-19.

Research published today in The Lancet Microbe finds a high prevalence of anosmia cases among healthcare workers between mid-February and mid-April.

Senior author Prof Carl Philpott, from UEA's Norwich Medical School, said: "Smell loss as a symptom of Covid-19 is particularly important for healthcare professionals because they are at the frontline of pandemic - and at high risk of both contracting and spreading the virus.

"In many cases smell loss can be the only symptom of Covid-19, or accompanied by mild symptoms.

"We wanted to find out how widespread smell loss has been among healthcare workers."

The research team distributed questionnaires to staff at London's Barts Health NHS Trust - one of the largest NHS trusts in the UK.

The questionnaire was completed by 262 healthcare workers in the week April 17-23. At this time, anosmia was not yet listed as an official symptom and covid-19 testing among NHS workers was still limited to those displaying symptoms of a new continuous cough and/or a high temperature (>37.8°C) as per national guidance.

Nevertheless, 73 (27.9 per cent) of the participants had been tested for Covid-19, with 56 of these (76.7 per cent) confirmed positive.

In line with Public Health England guidance at the time of the study, staff who only had anosmia as a symptom would not have been required to isolate or be eligible for testing. Like other trusts, staff testing for Covid-19 at Barts Health has been available since late March 2020. Loss of smell was included as a symptom in national guidance since May 18 2020 and any staff with that symptom are required to have a test

and self-isolate for seven days.

Prof Philpot said: "The really interesting thing that we found was that 168 of the participants - nearly two thirds - said that they had lost their sense of smell or taste at some point between mid-February and mid-April.

"We also found a strong association between smell loss and the positive Covid-19 test results, with those who had lost their sense of smell being almost five times more likely to test positive.

"This suggests that a large proportion of healthcare workers may have already been infected with Covid-19, with only mild symptoms.

"We conducted this research at Barts Health, however we would expect to see similar results from other NHS trusts too.

"Cases like this most likely went undiagnosed at the time because of a lack of awareness about smell loss as a symptom.

"This is really important because healthcare professionals are at the frontline of the pandemic and are at high risk of both contracting and spreading coronavirus.

"There is a need for awareness and early recognition of anosmia as a means to identify, urgently test and isolate affected healthcare workers in order to prevent further spread of disease," he added.

Rupert Pearse, clinical director for research and development at Barts Health NHS Trust said: "We're delighted to play a central role in supporting key research studies which help us better understand Covid-19. We know that NHS trusts that carry out research deliver better quality patient care and we are one of the leading contributors to clinical research across the NHS.

"Our staff have also volunteered to participate in a variety of important projects too and we are pleased to be able to support studies that focus on our healthcare workers."

The study also involved a follow-up survey in May, in which 47 per cent of respondents reported that their sense of smell and taste had completely recovered. A further 42 per cent said they had partially recovered their sense of smell and taste, but just over 7 per cent still suffered anosmia.

The survey has also been running in two Norfolk hospitals and in two hospitals in the North West with the responses of over 1,000 healthcare workers due to be published soon.

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The research was led by UEA in collaboration with Whipps Cross University Hospital (part of Barts Health NHS Trust), University College London, the Royal National ENT and Eastman Dental Hospitals (part of UCLH NHS Foundation Trust) and the Norfolk Smell & Taste Clinic, at Norfolk & Waveney ENT Service.

'Anosmia/hyposmia in healthcare workers with a SARS-CoV-2 infection' is published in The Lancet Microbe on August 6, 2020.

Peer reviewed - survey - people

Study finds dedicated clinics can reduce impact of flu pandemic

NORTH CAROLINA STATE UNIVERSITY

 

A new study concludes that opening clinics dedicated specifically to treating influenza can limit the number of people infected and help to "flatten the curve," or reduce the peak prevalence rate. While the work focused on influenza, the findings are relevant for policymakers seeking ways to reduce impacts of the ongoing COVID-19 pandemic.

"Dedicated clinics would have less of an impact than interventions such as vaccination, but at the statewide level, we're talking about cutting the overall number of infections by six figures," says Julie Swann, corresponding author of a paper on the work. Swann is the department head and A. Doug Allison Distinguished Professor of the Fitts Department of Industrial and Systems Engineering at North Carolina State University.

"And while our work here focused on the H1N1 strain of influenza, the findings are useful as we grapple with how best to respond to COVID-19," Swann says. "COVID-19 is more infectious than H1N1, and has a higher mortality rate. So I would expect the effect of using dedicated clinics to be larger for COVID-19."

Swann and her collaborators were inspired to do the study by the fact that some hospitals opened dedicated H1N1 clinics during the H1N1 influenza pandemic in 2009-2010. These clinics focused exclusively on treating patients who were exhibiting symptoms of H1N1. There was some question at the time as to whether these clinics were a good use of limited resources. It was also unclear as to whether the clinics may have had unintended consequences, such as spreading H1N1 to patients who showed up at the dedicated clinic with flu-like symptoms, but didn't actually have the disease.

For this study, Swann and her collaborators at Purdue University, Georgia Tech and Emory University used a simulation model to address questions related to the ultimate impact of dedicated clinics during an H1N1 pandemic.

The researchers found that opening dedicated clinics reduced disease spread and hospitalizations, particularly when open during the periods of peak prevalence - when the most people are sick. Specifically, the researchers found that if dedicated clinics were open for the entire duration of the pandemic, the clinics would have reduced the overall number of infections by 0.4-1.5%; reduced peak prevalence (or "flattened the curve") by 0.07-0.32%; and reduced hospitalizations by 0.02-0.09%.

"For a state that has a population of 10 million, the difference in the baseline clinic case would be about 100,000 cases, with about 6,000 hospitalizations averted," Swann says. "In other words, dedicated clinics certainly don't make things worse, and can make things at least a little better. And these are benefits that come on top of any benefits we'd see from other, behavioral changes - such as wearing masks - which may be more difficult to implement."

North Carolina's population is approximately 10.5 million.

The study on dedicated clinics is part of a larger research initiative that has already published work examining issues related to vaccine distribution for adults and children; the role of mass gatherings and travel in spreading influenza; and the impact of seasons and mutation in the spread of the disease.

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The paper, "The impact of opening dedicated clinics on disease transmission during an influenza pandemic," will be published Aug. 6 in the journal PLOS ONE. The paper was co-authored by Pengyi Shi of Purdue University; Jia Yan and Pinar Keskinocak of Georgia Tech; and by Dr. Andi Shane of Emory University and Children's Healthcare of Atlanta. The work was done with support from Georgia Tech, Edward P. Fitts and the A. Doug Allison Distinguished Professorship.

Identifying and contending with radioisotopes of concern at Fukushima

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

 

In this Perspective, Ken Buesseler describes the enormous challenges that remain in doing clean-up on land in Japan following the Fukushima Daiichi Nuclear Power Plant disaster in 2011, even as some progress has been made offshore. Buesseler notes that among the biggest unresolved issues is what to do with the more than 1,000 tanks at the plant site that contain contaminated water. One possible option for dealing with it is to release it into the ocean. It contains Tritium, 3H, which is notoriously difficult to remove because it is a radioactive form of hydrogen that is part of the water molecule itself. But, says Buesseler, while tritium has received much attention to date, the tank water also contains other radioactive isotopes that behave differently in the ocean and are more readily incorporated into marine biota or seafloor sediments. Buesseler argues that, to assess the consequences of releasing the tanks, "a full accounting ... of what isotopes are left in each tank is needed." Buesseler also suggests that options other than ocean discharge should be considered, moving forward. And he notes that public fears about the clean-up process "should not be dismissed" because these decisions may have negative impacts on local fisheries that are just now rebuilding.

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Why shaving dulls even the sharpest of razors

Human hair is 50 times softer than steel, yet it can chip away a razor's edge, a new study shows

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

 

Razors, scalpels, and knives are commonly made from stainless steel, honed to a razor-sharp edge and coated with even harder materials such as diamond-like carbon. However, knives require regular sharpening, while razors are routinely replaced after cutting materials far softer than the blades themselves.

Now engineers at MIT have studied the simple act of shaving up close, observing how a razor blade can be damaged as it cuts human hair -- a material that is 50 times softer than the blade itself. They found that hair shaving deforms a blade in a way that is more complex than simply wearing down the edge over time. In fact, a single strand of hair can cause the edge of a blade to chip under specific conditions. Once an initial crack forms, the blade is vulnerable to further chipping. As more cracks accumulate around the initial chip, the razor's edge can quickly dull.

The blade's microscopic structure plays a key role, the team found. The blade is more prone to chipping if the microstructure of the steel is not uniform. The blade's approaching angle to a strand of hair and the presence of defects in the steel's microscopic structure also play a role in initiating cracks.

The team's findings may also offer clues on how to preserve a blade's sharpness. For instance, in slicing vegetables, a chef might consider cutting straight down, rather than at an angle. And in designing longer-lasting, more chip-resistant blades, manufacturers might consider making knives from more homogenous materials.

"Our main goal was to understand a problem that more or less everyone is aware of: why blades become useless when they interact with much softer material," says C. Cem Tasan, the Thomas B. King Associate Professor of Metallurgy at MIT. "We found the main ingredients of failure, which enabled us to determine a new processing path to make blades that can last longer."

Tasan and his colleagues have published their results in the journal Science. His co-authors are Gianluca Roscioli, lead author and MIT graduate student, and Seyedeh Mohadeseh Taheri Mousavi, MIT postdoc.

A metallurgy mystery

Tasan's group in MIT's Department of Materials Science and Engineering explores the microstructure of metals in order to design new materials with exceptional damage-resistance.

"We are metallurgists and want to learn what governs the deformation of metals, so that we can make better metals," Tasan says. "In this case, it was intriguing that, if you cut something very soft, like human hair, with something very hard, like steel, the hard material would fail."

To identify the mechanisms by which razor blades fail when shaving human hair, Roscioli first carried out some preliminary experiments, using disposable razors to shave his own facial hair. After every shave, he took images of the razor's edge with a scanning electron microscope (SEM) to track how the blade wore down over time.

Surprisingly, the experiments revealed very little wear, or rounding out of the sharp edge over time. Instead, he noticed chips forming along certain regions of the razor's edge.

"This created another mystery: We saw chipping, but didn't see chipping everywhere, only in certain locations," Tasan says. "And we wanted to understand, under what conditions does this chipping take place, and what are the ingredients of failure?"

A chip off the new blade

To answer this question, Roscioli built a small, micromechanical apparatus to carry out more controlled shaving experiments. The apparatus consists of a movable stage, with two clamps on either side, one to hold a razor blade and the other to anchor strands of hair. He used blades from commercial razors, which he set at various angles and cutting depths to mimic the act of shaving.

The apparatus is designed to fit inside a scanning electron microscope, where Roscioli was able to take high-resolution images of both the hair and the blade as he carried out multiple cutting experiments. He used his own hair, as well as hair sampled from several of his labmates, overall representing a wide range of hair diameters.

Regardless of a hair's thickness, Roscioli observed the same mechanism by which hair damaged a blade. Just as in his initial shaving experiments, Roscioli found that hair caused the blade's edge to chip, but only in certain spots.

When he analyzed the SEM images and movies taken during the cutting experiments, he found that chips did not occur when the hair was cut perpendicular to the blade. When the hair was free to bend, however, chips were more likely to occur. These chips most commonly formed in places where the blade edge met the sides of the hair strands.

To see what conditions were likely causing these chips to form, the team ran computational simulations in which they modeled a steel blade cutting through a single hair. As they simulated each hair shave, they altered certain conditions, such as the cutting angle, the direction of the force applied in cutting, and most importantly, the composition of the blade's steel.

They found that the simulations predicted failure under three conditions: when the blade approached the hair at an angle, when the blade's steel was heterogenous in composition, and when the edge of a hair strand met the blade at a weak point in its heterogenous structure.

Tasan says these conditions illustrate a mechanism known as stress intensification, in which the effect of a stress applied to a material is intensified if the material's structure has microcracks. Once an initial microcrack forms, the material's heterogeneous structure enabled these cracks to easily grow to chips.

"Our simulations explain how heterogeneity in a material can increase the stress on that material, so that a crack can grow, even though the stress is imposed by a soft material like hair," Tasan says.

The researchers have filed a provisional patent on a process to manipulate steel into a more homogenous form, in order to make longer-lasting, more chip-resistant blades.

"The basic idea is to reduce this heterogeneity, while we keep the high hardness," Roscioli says. "We've learned how to make better blades, and now we want to do it."

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Written by Jennifer Chu, MIT News Office

Small towns have highest risk of intimate partner violence

WASHINGTON STATE UNIVERSITY

VANCOUVER, Wash. - Despite common perceptions that big cities have more violence, women living in small towns are most at risk of violence from current or former spouses and partners, according to a recent study by Washington State University criminologist Kathryn DuBois.

For the study, published in the Journal of Interpersonal Violence, DuBois analyzed the responses of more than 570,000 women from the National Crime Victimization Survey from 1994 to 2015. She found that women from small towns were 27% more likely to be victims of intimate partner violence than women from the center of big cities and 42% more likely than suburban women.

"In criminology, we often have this urban bias. We assume big cities are the worst and paint other places as idyllic," said DuBois, associate professor at WSU Vancouver. "We tend to think in a continuum from urban to suburban to rural, but for intimate partner violence, it's actually the suburban areas that are the safest, and small towns that have the highest risk."

The National Crime Victimization Survey collects information through a large sample of interviews about a range of personal crimes committed every year. Part of the intent of the survey is to uncover the "dark figure" of crime, DuBois said, those crimes that may not be reported to police.

While the survey defines many locations as simply urban or rural, DuBois analyzed the data by population density to delineate urban, suburban, small town and rural areas. Small towns were defined as urbanized portions of non-metropolitan counties with populations up to 50,000. They are distinct from suburban areas that exist just outside of big cities.

"Many surveys assume that everyone in those nonmetropolitan counties are the same, but there's a lot more heterogeneity across them," Dubois said.

DuBois originally undertook the study to try and reconcile the inconsistency between national surveys, which typically find rural areas have less or similar rates of intimate partner violence to urban areas--and ethnographic research, in-depth qualitative studies that have indicated that rural isolation can exacerbate gender-based violence.

While the study data cannot reveal the reasons behind the violence, the finding about the high rate of intimate partner violence in small towns indicates that there may be a different set of factors at play, DuBois said.

"Small towns have populations large enough to have the difficult problems of a big city, while at the same time these are some of the hardest hit areas economically, so they don't have specialized services and policing needed to deal with family violence," DuBois said.

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Impact of climate change on tropical fisheries would create ripples across the world

Tropical oceans and fisheries are threatened by climate change, generating impacts that will affect the sustainable development of both local economies and communities, and regions outside the tropics.

UNIVERSITY OF BRITISH COLUMBIA

 

IMAGE: THESE LINKAGES ENABLE THE FLOW OF BENEFITS, INCLUDING FOOD, LIVELIHOODS AND GOVERNMENT REVENUE, FROM TROPICAL FISHERIES TO EXTRATROPICAL LOCATIONS. FISH FROM THE TROPICS SOLD IN TEMPERATE-ZONE MARKETS PROVIDES JOBS AND... view more 

CREDIT: LAM ET AL, NATURE REVIEWS EARTH & ENVIRONMENT

Tropical oceans and fisheries are threatened by climate change, generating impacts that will affect the sustainable development of both local economies and communities, and regions outside the tropics through 'telecoupling' of human-natural systems, such as seafood trade and distant-water fishing, says a scientific review from UBC and international researchers.

Seafood is the most highly traded food commodity globally, with tropical zone marine fisheries contributing more than 50 per cent of the global fish catch, an average of $USD 96 billion annually. Available scientific evidence consistently shows that tropical marine habitats, fish stocks and fisheries are most vulnerable to oceanic changes associated with climate change. However, the scientific review highlights that telecoupling, or linkages between distant human-natural systems, could generate cascades of climate change impacts from the tropics that propagate to other 'extra-' tropical natural systems and human communities globally.

"Telecoupling interactions between two or more linked areas over distance between tropical fisheries and elsewhere include distant-water fishing, the international seafood supply chain, transboundary fisheries resources and their governance would allow benefits derived from tropical fisheries to transfer to the people in the extratropical regions," said Vicky Lam, lead author and research associate in the UBC's Institute for the Oceans and Fisheries. "Although these linkages could enable the flow of benefits, including food, livelihoods and government revenue, from tropical fisheries to extratropical locations, their dependence on tropical fisheries also exposes them to the negative consequences of climate change in tropical regions. The effects of climate change on tropical fisheries also affect the profitability and employment opportunities of fish-processing industries in extratropical regions."

"Pacific Island countries and territories, for example, are expected to see a redistribution of skipjack and yellowfin tuna - their two most exported fish species - that could see decreased catches of between 10 and 40 per cent by 2050 in many countries such as Palau and the Solomon Islands, while catches are expected to increase by 15 to 20 per cent in Kiribati and the Cook Islands. This will have a tremendous effect on the economies of these small island developing states," said Rashid Sumaila, co-author and professor at UBC's Institute for the Oceans and Fisheries and School of Public Policy and Global Affairs. "There are similar projections in African nations, where climate-related changes are expected to decrease the value of landed catch by approximately 20 per cent by 2050, as well as reduce fisheries-related jobs by 50 per cent."

To reduce the effect of climate change on the benefits derived from tropical fisheries, both locally and in extra-tropical regions, the root causes of climate-driven problems in tropical fisheries need to be recognized and rectified. Effective and practical adaptation and mitigation solutions with stakeholder commitment and involvement, as well as supporting policies, are therefore necessary in the tropics.

"We already see that there are close linkages between the tropical regions and the extra-tropical nations through trade and distant-water fishing" said William Cheung, co-author and professor at UBC's Institute for the Oceans and Fisheries. "Solving climate change impacts in the tropics will benefit the whole world; this provides an additional argument for non-tropical countries to support climate mitigation and adaptation in tropical countries."

Economic Telecoupling of Tropical Fisheries (IMAGE)

Annual average value (US$ million) of fish exports from Pacific Island countries and territories (PICTs) (panel a), Brazil (panel b) and Africa (panel c) to their main trading partners for 2014-2018 (left), and annual average landed values (US$ billions) of fish caught in the three corresponding groups of exclusive economic zones (EEZs) by the countries and territories in those regions and by distant-water fishing nations between 2007 and 2016 (right). There are close linkages between the tropical regions and the extratropical nations through trade and distant-water fishing, indicating that any climate-related changes to tropical fisheries have socio-economic implications for many extratropical nations. Note that values from the Pacific Islands region are for tuna only, and the catch values refer to tuna caught from the Western and Central Pacific Fisheries Convention Area, which is larger than the combined EEZs of PICTs (see Supplementary Tables 1,4-8). Source of data for panel a: Pacific Islands Forum Fisheries Agency.###

The article "Climate change, tropical fisheries and prospects for sustainable development" appeared in Nature Reviews Earth & Environment.