Culture

Despite the buzz in recent years about other invasive insects that pose an even larger threat to agriculture and trees -- such as the spotted lanternfly, the stink bug and the emerald ash borer -- Penn State researchers have continued to study another damaging pest, the Asian longhorned beetle.

Their most recent research revealed that the larval offspring of the wood-borer native to China can feed and thrive on tree species whose tissues would sicken their parents, perhaps explaining how the beetle expands its range, even when its preferred host trees -- maples, elms and willows -- are not nearby.
cut log with insect tunneling

The researchers' attention on Asian longhorned beetles remains well-placed because the U.S. Department of Agriculture's Animal and Plant Health Inspection Service has spent approximately $640 million to eradicate outbreaks of the wood-boring beetle in Illinois, New Jersey, New York and Massachusetts. And eradication efforts continue in New York, Massachusetts and Ohio.

The Asian longhorned beetle most likely came to the United States inside wood packaging material from Asia in the early 1990s, according to Kelli Hoover, professor of entomology. Her research group in the College of Agricultural Sciences has been studying the pest for 19 years.

"In North America, the beetle attacks and can kill dozens of species from 15 plant families," she said. "Northern hardwood forests reaching from the Atlantic Ocean to the Great Lakes and beyond are made up of vulnerable species -- approximately 48 million acres in the United States, plus the majority of Canada's hardwood forests."

This is not a new pest, but it still threatens billions of dollars in economic damage, Hoover pointed out, adding that if USDA had not undertaken its eradication efforts, Asian longhorned beetles would be causing a tremendous amount of damage over a much larger area.

"Those eradication efforts will have to continue," she said.
poster showing an Asian longhorn beetle under a magnifying glass

Some trees, such as poplar, have limited resistance to attacks by Asian longhorned beetles, noted lead researcher Charlie Mason, postdoctoral scholar in entomology. In trying to assess the difference in resistance between Chinese poplar and native poplar -- which consists of trees secreting compounds into their bark and wood tissues making them unpalatable to the wood-boring beetles -- the researchers made a startling discovery: Larval Asian longhorned beetles can consume tree tissues that the adults cannot.

In their study, researchers realized that different plant species had strong effects on adult performance, but these patterns did not extend to effects on juveniles consuming the same hosts. They saw that female adult beetles were capable of producing eggs when feeding on red maple, but not when provided eastern cottonwood, also called necklace poplar, or Chinese white poplar.

Yet females that produced eggs by feeding on red maple deposited eggs into all three plant species and the larvae that hatched from these eggs performed equally on the three hosts. The differences between adult and juvenile utilization of poplar was very different.

"That is because poplar has markedly higher salicinoid phenolic concentrations in bark, which discourage adult Asian longhorned beetles from feeding, while poplar wood had only trace amounts," said Mason. "The tree's resistance is due to compounds present in the bark that make it unpalatable for adults."

But the adult female cuts a small notch in the bark and deposits her eggs, and the hatched larvae from there are able to tunnel into the wood tissues and be nourished by eating them, avoiding having to feed on bark.

By feeding on the wood and burrowing through tree limbs, making them weak, unstable and liable at any time to collapse on people below, Asian longhorned beetle have wreaked havoc on trees in urban areas such as New York City, Worcester, Massachusetts, and Chicago. The damage they caused has resulted in the removal of thousands of infested trees.

This research, recently published in the Journal of Animal Ecology, offers insight into how the pest has survived sustained efforts to eradicate it, Hoover believes.

"Now we know that the host range is not equal between adults and larvae," she said. "The young ones appear to have a broader range of trees they can feed on because they can avoid the toxic chemicals in the bark."

Hamilton, ON (August 12, 2019) - A study from McMaster University has unearthed new details about the evolutionary history of both antibiotic production and resistance and dates their co-emergence as far back as 350 to 500 million years.

The study is the first to put antibiotic biosynthesis and resistance into an evolutionary context. The findings will help to guide the future discovery of new antibiotics and antibiotic alternatives which are medicines that are vitally needed given the current global threat of antimicrobial resistance.

The study was published in Nature Microbiology.

"Our findings are of significant interest," said Gerry Wright, senior author and professor of the Department of Biochemistry and Biomedical Sciences at McMaster. He is also director of the Michael G. DeGroote Institute for Infectious Disease Research and the newly established David Braley Centre for Antibiotic Discovery.

"Our study reveals several implications in how we could potentially manage antibiotic use and find new drugs for antimicrobial infections."

The team extracted this history by first identifying the genome sequences encoding all of the necessary genetic programs for the production of glycopeptide antibiotics within a group of bacteria called Actinobacteria. Glycopeptides include vancomycin and teicoplanin, essential medicines for treating bacterial infections.

Researchers then plotted the changes in these genetic programs over time, revealing that while the precursors for genes responsible for antibiotic production date back to over one billion years, resistance is contemporary with the production of the first ancestors of vancomycin-like drugs, dating back to 350 to 500 million years.

"The results we uncovered in this study offers a valuable lens through which to consider the current antibiotic crisis," said Nicholas Waglechner, first author and PhD candidate in the Gerry Wright lab. "These compounds have been useful to bacteria on the planet even before dinosaurs appeared, and resistance co-evolved with production as a means of self-protection for producing bacteria. The use of vancomycin in modern times in medicine and agriculture has resulted in the movement of resistance from these innocuous producers to disease-causing bacteria over a few short decades."

WASHINGTON -- Older workers whose reasoning abilities no longer allow them to meet the demands of their jobs may be more likely to develop chronic health conditions and retire early, which may not be ideal for the employee or employer, according to research published by the American Psychological Association.

"When their reasoning abilities matched the demands of their job, older adults experienced fewer health issues and worked longer than adults who did not have the necessary reasoning abilities to perform their job," said Margaret Beier, PhD, of Rice University and lead author of the study. "Experienced workers offer much in terms of knowing the company culture and being able to mentor younger employees, so it is vital that we look into the best ways to extend their careers and improve their health outcomes."

The study was published in the Journal of Occupational Health Psychology.

With a growing proportion of older adults in the workforce, Beier and her co-authors wanted to learn about the factors involved in maintaining health and determining when people choose to retire.

The authors used a subset of data from the Cognition and Aging in the USA survey, collected between 2007 and 2014 from 383 participants who remained in the study for the full seven years. The survey looked at a variety of factors, but the authors used the data collected on participants' abilities, health and retirement status over the course of the survey for this study. At the start of the survey, participants were all at least 51 years old. The average age was 61.

Researchers measured cognitive ability using a combination of 13 different measures, including verbal analogies (e.g., they were given three words of an analogy and must name the fourth), number series (e.g., they look at a number series and find the one missing) and calculations. The researchers also measured demands from jobs using the O*NET database, which reports the knowledge, skills, abilities and other attributes needed for many jobs in the United States. Participants were also asked to report if they had any of nine health conditions, including high blood pressure, arthritis, diabetes and lung disease.

"Mathematical reasoning may be important for both a middle school math teacher and a calculus professor, but the level of ability demanded for the calculus professor is higher than for the teacher," said Beier. "To measure health conditions, we summed up the number of chronic health conditions participants reported in the Cognition and Aging in the USA study. Retirement status was measured simply by asking the participants about their current employment situation."

Researchers found that having reasoning abilities that matched the demands of the job was important to the positive experience of work in older age. When reasoning abilities required by a job exceeded a worker's abilities, workers reported more health conditions and were more likely to be retired, said Beier. When workers' reasoning abilities met or exceeded a job's demands, they also reported fewer chronic health conditions.

"We found that a poor fit between reasoning abilities and job demands might cause older workers to experience stress and strain that serves to push them out of the workforce," said Beier.

Reasoning abilities decline with age, so organizations must be aware of how employee health can be negatively affected by the demands placed upon an employee, said Beier. Older workers can handle highly complex jobs as long as they have the mental resources to match the job demands.

The results of this study could inform decisions on how jobs for older employees should be designed to reduce the potential for negative health outcomes and retain these veteran employees as long as possible before retirement, according to Beier.

"With the average age of retirement increasing across the country and the older population itself becoming a larger portion of the population, it is important that we study how the demands placed on older workers in the workforce should match their abilities," said Beier. "Older workers have such valuable experience that it is vital we look into the best ways to extend their careers and improve their health outcomes."

OAKLAND, CA - According to new research released today in the Proceedings of the National Academy of Sciences, race influences the investment judgments of asset allocators. Experts believe this may contribute to the stark racial disparities in the world of institutional investing.

The study is the first report from the new research partnership initiated by private investment firm, Illumen Capital, and led in collaboration with Stanford SPARQ, a do-tank that partners with industry leaders to tackle disparities and inspire culture change through behavioral science. The partnership aims to promote fairness across the financial services industry by examining how unconscious bias drives racial and gender disparities in the sector.

"We're living in a society where we're absorbing images and ideas all the time that influence who we are and how we see the world, even when we're not aware of it," said Dr. Jennifer Eberhardt, a psychologist and expert on bias who led the Stanford SPARQ research team, and is the author of Biased. "This study takes a necessary and critical look at how bias impacts the investing space through the lens of those in power and provides insight into how decision-makers can better resolve those challenges going forward."

Importance of Study. As the report highlights, "asset allocators" operate via pension funds, endowments, foundations, and sovereign funds, performing two key functions for society and their sponsors: providing high rates of return for the organizations they represent and acting as the base of the global capitalist system, allocating their funds to countless investment opportunities around the world, often through for-profit financial intermediaries (venture capitalists, hedge funds, private equity funds) managed by professional fund managers who attempt to generate a high investment return.

Given their power and influence, it is critical to understand how these asset allocators deploy capital and make investment judgements, particularly across third party fund managers. If asset allocators set incorrect or biased incentives, the entire capitalist system will reflect and reinforce these biases.

Furthermore, while there are $69.1 trillion of global financial assets under management across mutual funds, hedge funds, real estate and private equity, fewer than 1.3 percent are managed by women and people of color. A comprehensive data set of every venture capital organization and investor since 1990 shows that the industry has remained "relatively homogeneous" for the past 28 years, particularly white and male. Women represent only 8 percent of investors. Hispanics make-up just 2 percent of venture capitalist investors and fewer than 1 percent are black. And there has been no systematic investigation of the factors that cause those disparities in investment decision-making until now.

"I've observed investors leaving money on the table because they underestimate the value of funds managed by people of color and women," said Daryn Dodson, an impact investor, who is the founder and managing director of Illumen Capital, which he founded to address this gap. "But many of these investors did not seem to harbor conscious prejudices or even notice their biased behavior. This leads me to believe that the problem can be addressed, but we must first clearly define why these issues exist. This is true for professionals in the impact investing space too, who, seeking to improve society and achieve returns can never fully reach their goals without addressing racial bias."

About the Study. "Identifying the root of racial disparities in investing is challenging because there are so few people of color in this space to begin with," said Dr. Sarah Lyons-Padilla, a research scientist at SPARQ and leading author of the study. "Are investors biased against racially diverse teams, or is there just not enough diversity in the pipeline? We decided our first step should be to design a controlled experiment that could tell us whether, all qualifications equal, racially diverse teams face more scrutiny than their racially homogeneous counterparts."

The research team explored three distinct theories that could explain disparities in investing: 1) there is no investor bias against funds owned by people of color, suggesting that the issue is primarily a talent pipeline problem; 2) bias exists predominantly at weaker levels of performance - below the bar; and 3) bias exists predominantly at stronger levels of performance--above the bar.

The study examined differences in judgment among asset allocators when all details about a fund's track record and qualifications were kept constant except race. Through an online experiment with actual asset allocators, the research team sought to determine whether there are biases in their evaluations of funds owned by black men in particular, and, if so, how these biases manifest.

Research Findings.

Asset allocators have trouble gauging the competence of racially diverse teams. Asset allocators' judgments of the team's competence were more strongly correlated with predictions about future performance (e.g., money raised) for racially homogenous teams than for racially diverse teams.

Racially diverse teams face bias at the top. At stronger performance levels, asset allocators rated white-led funds more favorably than they did black-led funds when evaluating investment skills, competence, and social fit.

Racially diverse teams get the benefit of the doubt at the bottom, but not more funding. At weaker performance levels, asset allocators actually rated black-led teams more favorably than white-led teams in terms of overall performance, investment skills, and ability to raise money. However, asset allocators expressed little interest in investing in weaker funds, diverse or otherwise.

"Controlling assets of nearly $100 trillion, the influence that these beneficial institutional investors have on the entire chain of financial intermediation, capitalism and even society cannot be overstated," added Dr. Ashby Monk, a member of the SPARQ team and executive director of the Global Projects Center at Stanford. "It is of the highest importance that they invest and operate without bias. This paper and its findings hopefully raise awareness of the types of biases that remain. Racial bias is still alive and well in our country and its system of capitalism, and the investment community needs to do more to counter it in order to live up to their fiduciary obligations."

Dr. Hazel Markus, co-director of SPARQ, noted that this careful analysis of the judgements of actual asset allocators reveals that the same types of biases that social psychologists have long documented in many arenas of society--education, employment, and everyday social life--are also at work in the powerful financial services industry. Rather than an emphasis on "fixing" individual financial decision-makers, however, the results suggest the value of a systematic approach to implementing practices that counteract these pervasive biases.

Conclusion. The results suggest first that underrepresentation of people of color in the realm of investing is not only a talent pipeline problem, and second, that funds led by people of color might paradoxically face the most barriers to advancement after they have established themselves as strong performers.

"This study highlights the tangible business value represented by diverse teams, which, when left unrecognized, leaves profit and opportunity on the table," said Lata Reddy, senior vice president of Prudential Financial's Diversity, Inclusion & Impact team, the report's lead sponsor. "Black and Latino Americans wield almost $3 trillion in combined purchasing power today, and that's projected to grow. Companies concentrating on racial equity have created new business value and improved their bottom line. As this study shows, investing in those groups that have been historically marginalized can strengthen not only the talent pipeline, but the advancement of people of color in their careers and their communities."

Additional research is expected to examine solutions in more depth. However, investing experts advising on the study believe that research, awareness-raising, professional training, and coaching as well as intentional changes to long-time industry practices, can improve the future make-up and impact of the investment community, changing the power dynamic to one that is more equitable and culturally significant.

New research led by Oxford University and Queen Mary University of London has resolved a pig paradox. Archaeological evidence has shown that pigs were domesticated in the Near East and as such, modern pigs should resemble Near Eastern wild boar. They do not. Instead, the genetic signatures of modern European domestic pigs resemble European wild boar.

Published in Proceedings of the National Academy of Sciences, the study shows how this has happened. Working with more than 100 collaborators, researchers from Oxford's School of Archaeology sequenced DNA signatures from more than 2,000 ancient pigs including genomes from 63 archaeological pigs collected across the Near East and Europe over the last 10,000 years.

The findings revealed that the first pigs to arrive into Europe alongside farmers 8,000 years ago had clear Near Eastern genetic ancestry. Over the course of the next 3,000 years, however, ancient domestic pigs hybridised with European wild boar to such an extent that they lost almost all their Near Eastern ancestry. Some low level of Near Eastern ancestry, however potentially remained in the genome of modern European domestic pigs, and this likely explains their characteristic black, and black and white spotted coat colours. Higher level of Near Eastern ancestry were also maintained in pig populations on Mediterranean islands maintained probably because these populations experienced comparatively less gene flow with European wild boar relative to pigs on the continent.

Professor Greger Larson, Director of the Palaeogenomics & Bio-Archaeology Research Network (PalaeoBarn) at Oxford and senior author of the study, said: "Having access to ancient genomes over such a large space and time has allowed us to see the slow-motion replacement of the entire genome of domestic pigs. This suggests that pig management in Europe over millennia was extensive, and that though swineherders maintained selection for some coat colours, domestic pigs interacted with wild boar frequently enough that they lost the ancestral signature of the wild boar from which they were derived."

Dr. Laurent Frantz, lead author of the study at Queen Mary University of London, said: "We are all taught that the big change was the initial process of domestication, but our data suggests that almost none of the human-selection over the first 2,500 years of pig domestication has been important in the development of modern European commercial pigs."

Now that the team have pieced together a timeline of the genomic history of pigs in western Eurasia, the next steps in the research will be to precisely identify, in the genome of modern European domestic pigs, the few genes that retained their original Near Eastern ancestry. This will allow us to assess whether the artificial selection applied by early farmers in the Fertile Crescent, over 10,000 years ago, left any further legacy in modern pigs beyond coat colour.

The molecular machinery used by bacteria to resist chemicals designed to kill them could also help produce precursors for a new generation of nylon and other polymers, according to new research by scientists from Australia and the UK.

"Resistance to artificial antiseptics appears to be a lucky accident for the bacteria, and it could also be useful for humans," says Professor Ian Paulsen of Australia's Macquarie University, one of the leaders of the research group.

Bacteria that are unaffected by antiseptics and antibiotics, often termed "superbugs", are a growing problem, but exactly how they develop resistance is not fully understood.

In 2013 Paulsen and colleagues discovered how a bacterium called Acinetobacter baumannii resisted chlorhexidine, a powerful hospital-grade antiseptic listed by the World Health Organisation as an "essential medicine".

A. baumannii's secret weapon, they found, is a protein called AceI, which sits on its surface and pumps out any chlorhexidine that gets inside. That was surprising, because the protein has been around for a lot longer than the antiseptic.

"The gene that encodes the AceI protein appears to be very old, but chlorhexidine was only created in the twentieth century," says lead author Dr Karl Hassan, from Australia's University of Newcastle.

"So the gene can't have the native function of protecting against chlorhexidine. It's a side reaction that is fortunate for the bacteria."

Now Hassan, Paulsen and colleagues have looked at what other compounds are transported by AceI and its relations, collectively known as Proteobacterial Antimicrobial Compound Efflux (PACE) proteins.

They found good news and bad news. The bad news was that PACE proteins are likely to be future engines of antimicrobial resistance. The good news is that their ability to transport a wide range of substances means that they could be effectively repurposed in an industrial context to catalyse the manufacture of "petroleum-free" polymers such as nylon.

"These PACE proteins are very promiscuous in the compounds that they transport and are a likely cause of future resistance to new antimicrobials that are currently being developed," says Professor Peter Henderson at the University of Leeds, a senior researcher on the team.

Rainfall variations in the tropics not only potentially influence 40% of the world's population and the stability of the global ecosystem, but also the global hydrologic cycle and energy balance.

Beginning in the 20th century, a decline in northern tropical rainfall has been observed, with researchers unsure whether the decline stems from natural or anthropogenic causes.

New rainfall research has shed some light on this question, but left the final answer up in the air.

Recently, an international team led by Prof. TAN Liangcheng from the Institute of Earth Environment (IEE) of the Chinese Academy of Sciences developed a 2700-yr rainfall record of the northern central Indo-Pacific region. The team's findings will be published in PNAS.

The researchers got official permission to collect stalagmites from the Klang Cave in southern Thailand. They used oxygen records and radiometric U-Th dating techniques with precision of half a year at best on three stalagmites to reveal regional rainfall history over the past 2700 years. Results show millennial-scale decreasing regional rainfall, similar to other records from the northern tropics and opposite to southern tropical records.

This tropical interhemispheric precipitation seesaw pattern was most likely driven by changes in summertime insolation in each respective hemisphere. Notable centennial-decadal-scale dry (950-1150, 1200-1350, and 1910 to present) and wet (400-800) climate episodes occurred.

The extreme decadal wet event during the late 14th century and early 15th century coincided with extensive floods and destruction of the water management systems in Angkor, Cambodia, indicating the hydroclimatic impact on the decline of the Khmer Empire in the 15th century.

The scientists also developed a 2000-yr Intertropical Convergence Zone (ITCZ) shift index record, which shows an overall southward shift over the past two millennia, and southward mean positions of ITCZ during the early Medieval Warm Period and the Current Warm Period in the central Indo-Pacific.

The scientists noted that the drying trend in the northern tropics since the early 20th century is similar to that from 950-1150 AD, which was attributed to a southward ITCZ shift and enhanced El Niño-like conditions. As a result, possible anthropogenic rainfall remains indistinguishable from natural variability in the northern tropics, Prof. TAN said. In other words, no clear case can be made that the recent northern tropical drying trend is caused by anthropogenic forces.

Although the cause of the last century's drying trend is uncertain, Prof. TAN sees a benefit in understanding historical rainfall trends.

"The rainfall variability during past warm periods can provide a historical analog to future trends under global warming, and help improve the precision of climate models," Prof. TAN said.

A California law that limits the size of bills from out-of-network physicians for care delivered in hospitals appears to be protecting patients' financial liability, but has shifted bargaining leverage in favor of insurance plans and had potential unintended consequences such as encouraging more consolidation among physician practice groups, according to a new RAND Corporation study.

Implemented in July 2017, the law appears to be successfully protecting patients from surprise medical bills from out-of-network physicians when they have nonemergency care delivered at in-network hospitals. Patients are now only required to pay in-network cost sharing.

However, the law has eroded the leverage that smaller physician groups have when negotiating payment contracts with hospitals, speeding consolidation among medical practices and increasing concerns that some types of specialists may refuse to participate in on-call panels, especially for late-night hours.

The findings are published online by the American Journal of Managed Care.

"The approach taken by California legislation that limits the fees that can be charged by out-of-network physicians appears to be reducing the number of surprise medical bills that patients receive for care at in-network hospitals," said Erin L. Duffy, author of the study and an adjunct researcher at the nonprofit RAND Corporation. "It also appears to be reducing physicians' leverage to negotiate higher in-network payments, and in turn is speeding the consolidation of physician groups as they seek to regain lost leverage."

Efforts have been growing to address the issue of patients receiving large, unexpected physician bills when they receive care at hospitals that are a part of their insurance plan's network. Efforts are going to address the Studies suggest that patients received surprise medical bills in as many as one in 10 elective admissions and in as many as one in five emergency admissions.

California adopted AB-72 in 2017 that set limits on how much can be charged by out-of-network physicians for nonemergency services at in-network hospitals. Patients pay only their in-network cost sharing obligation, and insurance plans pay the out-of-network professionals the greater of the payer's local average contracted rate or 125 percent of Medicare's fee-for-service rate.

The law applies only to insurance plans that are governed by California's insurance laws, which account for about half of all people in the state with private insurance. (Self-funded private health insurance plans -- typically those offered by larger employers -- are regulated by federal insurance laws and are not affected by the California rules.)

Duffy assessed the effects of the California legislation by conducting semistructured interviews with 28 stakeholders 6 to 12 months after AB-72 was put into force. Those interviewed include representatives of advocacy organizations and state-level professional associations, as well as executives of physician practice groups, hospitals and health benefit companies.

The stakeholders reported that while the law applied only to out-of-network providers, it diminished the leverage of all physician groups because doctors could no longer walk away from contract negotiations because they might be paid less as out-of-network providers. In order to regain leverage, hospital-based physicians are consolidating and also pursuing exclusive contracts with health care facilities.

In addition, some stakeholders reported that some specialists such as neurologists and surgeons had dropped off on-call lists. They expressed concerns that the trend could pose a hardship at hospitals that treat a large number of Medi-Cal patients, where physicians may rely on high commercial payments to cross-subsidize low Medi-Cal rates.

RESEARCH TRIANGLE PARK, N.C. -- A U.S. Army project discovery upends previous notions about how metals deform and could help guide the creation of stronger, more durable materials for military vehicles.

For nearly 100 years, scientists thought they understood everything there was to know about how metals bend. They were wrong.

Materials science and engineering researchers at the University of Wisconsin-Madison, funded by the Army Research Office, demonstrated that the rules of metal bending aren't so hard-and-fast after all. The researchers' new mechanism for bending, published in Nature Communications, might allow engineers to strengthen a material without running the risk of fractures.

The Army Research Office is an element of U.S. Army Combat Capabilities Development Command's Army Research Laboratory.

"This creates new opportunities for materials design," said Izabela Szlufarska, a professor of materials science and engineering at UW-Madison. "It adds another parameter we can control to enable strength and ductility."

"Professor Szlufarska has opened up an entirely new area for exploration for structural materials processing and design," said Dr. Michael Bakas, synthesis and processing program manager at Army Research Office. "By making such a high impact discovery, Professor Szlufarska has potentially laid the technical foundation for the development of a new generation of advanced structural materials that could eventually be employed in future Army equipment and vehicles."

Currently, engineers manipulate the strength of a metal through techniques such as cold working or annealing, which exert their effects through small, yet important, structural irregularities called dislocations.

"Everybody in the metals community knows that dislocations are critical," Szlufarska said.

It's a truism that's held since 1934, when three researchers independently realized that dislocation explained an ages-old paradox: Metals are much easier to bend than their molecular structures--which typically take the form of regularly repeating three-dimensional grids--would suggest.

Dislocations are tiny irregularities in the otherwise well-ordered crystal lattice of a metal. They arise from slight mismatches--picture the pages of a book as rows of atoms, and imagine how the neat stack of paper becomes ever-so-slightly distorted at the spot where someone inserts a bookmark.

Normal metals bend because dislocations are able to move, allowing a material to deform without ripping apart every single bond inside its crystal lattice at once.

Strengthening techniques typically restrict the motion of dislocations.

So, it was quite a shock when Szlufarska and colleagues discovered that the material samarium cobalt, known as an intermetallic, bent easily, even though its dislocations were locked in place.

"It was believed that metallic materials would be intrinsically brittle if dislocation slip is rare," said Hubin Luo, University of Wisconsin-Madison staff scientist. "However, our recent study shows that an intermetallic can be deformed plastically by a significant amount even when the dislocation slip is absent."

Instead, bending samarium cobalt caused narrow bands to form inside the crystal lattice, where molecules assumed a freeform "amorphous" configuration instead of the regular, grid-like structure in the rest of the metal.

Those amorphous bands allowed the metal to bend.

"It's almost like lubrication," Szlufarska said. "We predicted this in simulations, and we also saw the amorphous shear bands in our deformation studies and transmission electron microscopy experiments."

A combination of computational simulations and experimental studies was critical to explaining the result.

Next, the researchers plan to search for other materials that might also bend in this peculiar manner. Eventually, they hope to use the phenomenon to tune a material's properties for strength and flexibility.

"This might change the way you look for optimization of material properties," Szlufarska said. "We know it's different, we know it's new, and we think we can use it."

"While there is a long road of further research ahead, Professor Szlufarska's discovery certainly opens up new avenues to explore for extramural and Army researchers working in structural materials," Bakas said. "It is this type of fundamental research discovery that eventually results in the advanced materials that will protect soldiers 25 to 30 years from now."

Welcome to the early solar system. Just after the planets formed more than 4.5 billion years ago, our cosmic neighborhood was a chaotic place. Waves of comets, asteroids and even proto-planets streamed toward the inner solar system, with some crashing into Earth on their way.

Now, a team led by University of Colorado Boulder geologist Stephen Mojzsis has laid out a new timeline for this violent period in our planet's history.

In a study published today, the researchers homed in on a phenomenon called "giant planet migration." That's the name for a stage in the evolution of the solar system in which the largest planets, for reasons that are still unclear, began to move away from the sun.

Drawing on records from asteroids and other sources, the group estimated that this solar system-altering event occurred 4.48 billion years ago--much earlier than some scientists had previously proposed.

The findings, Mojzsis said, could provide scientists with valuable clues around when life might have first emerged on Earth.

"We know that giant planet migration must have taken place in order to explain the current orbital structure of the outer solar system," said Mojzsis, a professor in the Department of Geological Sciences. "But until this study, nobody knew when it happened."

It's a debate that, at least in part, comes down to moon rocks collected by Apollo astronauts--many of which seemed to be only 3.9 billion years old, hundreds of millions of years younger than the moon itself.

To explain those ages, some researchers suggested that our moon, and Earth, were slammed by a surge of comets and asteroids around that time. But not everyone agreed with the theory, Mojzsis said.

"It turns out that the part of the moon we landed on is very unusual," he said. "It is strongly affected by one big impact, the Imbrium Basin, that is about 3.9 billion years old and affects nearly everything we sampled."

To get around that bias, the researchers decided to compile the ages from an exhaustive database of meteorites that had crash landed on Earth.

"The surfaces of the inner planets have been extensively reworked both by impacts and indigenous events until about 4 billion years ago," said study coauthor Ramon Brasser of the Earth-Life Science Institute in Tokyo. "The same is not true for the asteroids. Their record goes back much further."

But those records, the team discovered, only went back to about 4.5 billion years ago.

For the researchers, that presented only one possibility: The solar system must have experienced a major bombardment just before that cut-off date. Very large impacts, Mojzsis said, can melt rocks and variably reset their radioactive ages, a bit like shaking an etch-a-sketch.

Mojzsis explained that this carnage was likely kicked off by the solar system's giant planets, which researchers believe formed much closer together than they are today. Using computer simulations, however, his group demonstrated that those bodies started to creep toward their present locations about 4.48 billion years ago.

In the process, they scattered the debris in their wake, sending some of it hurtling toward Earth and its then-young moon.

The findings, Mojzsis added, open up a new window for when life may have evolved on Earth. Based on the team's results, our planet may have been calm enough to support living organisms as early as 4.4 billion years ago.

What The Study Did: This study (called a systematic review and meta-analysis) combined the results of 21 studies with about 128,000 participants to quantify the association between electronic cigarette use and marijuana use among adolescents and young adults.

Author: Nicholas Chadi, M.D., M.P.H., of Boston Children's Hospital and Harvard Medical School in Boston, is the corresponding author.

(doi:10.1001/jamapediatrics.2019.2574)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Scientists have discovered that the gut-infecting bacterium Clostridium difficile is evolving into two separate species, with one group highly adapted to spread in hospitals. Researchers at the Wellcome Sanger Institute, London School of Hygiene & Tropical Medicine and collaborators identified genetic changes in the newly-emerging species that allow it to thrive on the Western sugar-rich diet, evade common hospital disinfectants and spread easily. Able to cause debilitating diarrhoea, they estimated this emerging species started to appear thousands of years ago, and accounts for over two thirds of healthcare C. difficile infections.

Published in Nature Genetics today (12 August), the largest ever genomic study of C. difficile shows how bacteria can evolve into a new species, and demonstrates that C. difficile is continuing to evolve in response to human behaviour. The results could help inform patient diet and infection control in hospitals.

C. difficile bacteria can infect the gut and are the leading cause of antibiotic-associated diarrhoea worldwide*. While someone is healthy and not taking antibiotics, millions of 'good' bacteria in the gut keep the C. difficile under control. However, antibiotics wipe out the normal gut bacteria, leaving the patient vulnerable to C. difficile infection in the gut. This is then difficult to treat and can cause bowel inflammation and severe diarrhoea.

Often found in hospital environments, C. difficile forms resistant spores that allow it to remain on surfaces and spread easily between people, making it a significant burden on the healthcare system.

To understand how this bacterium is evolving, researchers collected and cultured 906 strains of C. difficile isolated from humans, animals, such as dogs, pigs and horses, and the environment. By sequencing the DNA of each strain, and comparing and analysing all the genomes, the researchers discovered that C. difficile is currently evolving into two separate species.

Dr Nitin Kumar, joint first author from the Wellcome Sanger Institute, said: "Our large-scale genetic analysis allowed us to discover that C. difficile is currently forming a new species with one group specialised to spread in hospital environments. This emerging species has existed for thousands of years, but this is the first time anyone has studied C. difficile genomes in this way to identify it. This particular bacteria was primed to take advantage of modern healthcare practices and human diets, before hospitals even existed."

The researchers found that this emerging species, named C. difficile clade A, made up approximately 70 per cent of the samples from hospital patients. It had changes in genes that metabolise simple sugars, so the researchers then studied C. difficile in mice**, and found that the newly emerging strains colonised mice better when their diet was enriched with sugar. It had also evolved differences in the genes involved in forming spores, giving much greater resistance to common hospital disinfectants. These changes allow it to spread more easily in healthcare environments.

Dating analysis revealed that while C. difficile Clade A first appeared about 76,000 years ago, the number of different strains of this started to increase at the end of the 16th Century, before the founding of modern hospitals. This group has since thrived in hospital settings with many strains that keep adapting and evolving.

Dr Trevor Lawley, the senior author from the Wellcome Sanger Institute, said: "Our study provides genome and laboratory based evidence that human lifestyles can drive bacteria to form new species so they can spread more effectively. We show that strains of C. difficile bacteria have continued to evolve in response to modern diets and healthcare systems and reveal that focusing on diet and looking for new disinfectants could help in the fight against this bacteria."

Prof Brendan Wren, an author from the London School of Hygiene & Tropical Medicine, said: "This largest ever collection and analysis of C. difficile whole genomes, from 33 countries worldwide, gives us a whole new understanding of bacterial evolution. It reveals the importance of genomic surveillance of bacteria. Ultimately, this could help understand how other dangerous pathogens evolve by adapting to changes in human lifestyles and healthcare regimes which could then inform healthcare policies."

Largescale 'disturbances', including fires, harvesting, windstorms and insect outbreaks, which kill large patches of forest, are responsible for more than a tenth of tree death worldwide, according to new research at the University of Birmingham.

The research, published in Nature Geoscience, also showed wide regional variation, with parts of Scandinavia, the USA, Canada and Russia having a particularly high frequency of these disturbances.

Mapping the causes of tree death is important because it helps scientists understand how the world's carbon stocks - stored in forests - are affected by these disturbances and the frequency with which they occur.

Researchers in the Institute for Forest Research (BIFoR) at the University of Birmingham studied satellite-based observations of forest lost between 2000 and 2014, and assessed the typical time interval between large disturbance events across the world's forests.

The team then used a computational model to calculate the impact of these events on tree deaths - measured as the amount of carbon stored in the wood of dead trees - and found that they accounted for 12 per cent of tree death overall. Their simulations showed how even small changes to the frequency of large-scale disturbances can have a significant effect on forest carbon stocks in 44 per cent of the world's dense forests.

The model will enable scientists to better understand the context of events such as the recent wildfires which devastated parts of the Arctic.

Lead author, Dr Thomas Pugh, of the Institute for Forest Research at the University of Birmingham, said: "Large patches of dead forest make a dramatic impact on the landscape, be they caused by fires, harvesting, windstorms or insect outbreaks. But despite having been able to observe these events from space for many years, the contribution that they make to tree mortality and impact on forest carbon storage across the world has been unknown."

"Now we can see much more clearly where large disturbances play major roles and where forest carbon stocks are sensitive to changes in disturbance frequency."

He added: "This year's large fires across the Arctic may just be an anomaly, or they could be a sign that disturbances in that region are becoming more frequent relative to the historical norm. If that's the case, we can expect large amounts of carbon to be released from these forests over the coming century and perhaps wholesale changes in the mix of vegetation that make up the forests."

More work is now needed to study the reasons behind the remaining 88 per cent of the world's tree death to calculate the contributions of factors such as competition, drought, and older trees dying off.

Are you tired? A new study of young and middle-aged adults shows it could be happening because of the way society functions in your part of the world.

Researchers from Flinders University and the University of Helsinki collaborated with Finnish company, Polar, to compare the sleeping habits of 17,335 people wearing fitness trackers to measure their 14 day sleep patterns.

As published in in Sleep Medicine, they looked at sleep duration, sleep midpoint and weekend catch up for participants aged 16 to 30.

Sleep expert Professor Michael Gradisar says the study indicates differences in sleep durations shift dramatically throughout adolescence and stabilise near 30 years of age around the world.

"Sleep duration ranged from 7:53 hrs at age 16 to 7:29 hrs at age 30. There were also clear differences between females and males throughout adolescence and young adulthood, with girls having longer sleep and earlier timed sleep." says Professor Gradisar.

"In recent decades, there have been reports of delayed sleep in young people, characterised by very late bedtimes, and difficulties waking up in the morning at a socially-appropriate time. As sleep is a central element in functioning, health, and wellbeing, the reliable detection of sleep patterns is a key interest."

The results also show location matters- with people in the Middle East, Asia and Southern Europe getting significantly less sleep when compared to everyone else.

"Young adults in Asia had the shortest sleep duration (6hr 30min), whereas those in Oceania (7hr 14min) and Europe, (7hr 7min) had the longest. Young adults in Central and Southern America and the Middle East also reported short sleep (6hr 40min),"

"Higher work and educational demands in Asian countries compared to the west likely explain the later shorter sleep duration, coupled with similar catch up sleep, seen in those Asian regions."

"For example, when I was in Hong Kong last year speaking to colleagues, they informed me of Typhoon Mangkhut, which was one of the most destructive storms in the city's history. The very next day, workers were ordered to go back to work by a billionaire tycoon. My colleagues spoke of walking to work, stepping over fallen trees, and broken windows and paper in the streets. This is a city that doesn't rest - and part of a region that doesn't sleep much."

"So our findings suggest that cultural factors likely impinge upon the sleep opportunity of young people around the world."

HOUSTON - (Aug. 12, 2019) - Rice University scientists have found a way to engineer a new kind of cell differentiation in bacteria, inspired by a naturally occurring process in stem cells.

They have created a genetic circuit able to produce genetically distinguished cells of Escherichia coli as the bacterium divides. By controlling this process, it is possible to create diverse communities of microbes that exhibit complex, non-native behaviors.

Rice synthetic biologist Matthew Bennett and Sara Molinari, a former student in the university's Systems, Synthetic and Physical Biology Ph.D. program, led the project to show how manipulating the genetic code of plasmids -- free-floating pieces of circular DNA in cells -- can be used to obtain stem cell-like differentiation in bacteria.

"Stem cells have the remarkable ability to divide asymmetrically," Bennett said. "Upon division, the original stem cell stays the same, but the new daughter cell has a completely new phenotype. That's asymmetric cell division, and multicellular organisms use it to help control their cellular makeup.

"As a synthetic biologist, I think a lot about creating and controlling differentiated cell types within a multicellular population," he said. "Here, we've taken what we know about stem cells and engineered the means to do it in bacteria."

The researchers reported the development, which they call asymmetric plasmid partitioning (APP), in Nature Chemical Biology.

Molinari first discovered how to force plasmids in E. coli to aggregate in a single cluster so they do not distribute homogeneously during cell division, but rather are inherited by only one of the two daughter cells. The plasmid-laden daughter cell remains identical to the progenitor cell, while its sibling becomes genetically distinct as it loses the genetic information present on the plasmids.

She then expanded the synthetic circuit to induce the simultaneous asymmetric partitioning of two plasmid species in a single cell, resulting in four genetically distinct E. coli. Some of the cells have motility programmed in; they can literally go their own way and help form patterns in the resulting colony.

"When we started, we were thinking about creating materials that have to be able to sense and adapt to an environment," said Molinari, who recently earned her doctorate at Rice. "We thought if we could mimic this feature of higher-order tissues, we would increase the robustness of our colonies and their ability to perform tasks. The challenge was to engineer a population of bacteria that becomes something else whenever it's needed."

Molinari and her colleagues hit the jackpot on their first try with E. coli. "There was no canonical way to engineer asymmetrical cell division," she said. "It was a crazy idea, and it magically worked the first time.

"But there was something we couldn't completely figure out about the system," Molinari said. "It took two years to find out I made a cloning mistake when I got this protein and put it in my plasmid. I had randomly added 17 amino acids at the beginning of the protein, and that made the whole system work."

With that knowledge, she proceeded to improve upon the hydrophobic proteins that cluster in cells while they bind to target plasmids, holding them in place.

Bennett noted natural processes either load enough plasmids into a cell to ensure some land in each daughter cell or actively pull plasmids into each of the new cells to ensure they remain identical. "We have shown we can outcompete those processes," he said.

APP could turn simple organisms into complicated systems that enhance understanding of multicellular life. "We're pretty good at designing bacteria," Bennett said. "We've been doing that for years now. I think the field has evolved to the point where we can do amazing things with bacteria and people are asking what else we can do."

The new discovery, he said, provides a path forward.

"There are three main hallmarks to multicellular life," he said. "One is differentiation through asymmetric cell division. Another is intercellular communication, which synthetic biologists have been engineering for years. And the third is cell adhesion, so cells stay where they're supposed to and stick to each other. If we can control all those things together, we can talk about engineering interesting multicellular lifeforms.

"It starts to feel a bit like science fiction, for sure," he said.