Culture

A rice gene that renders the crop resistant to several widely used beta-triketone herbicides has been identified, researchers report, revealing the genetic cause of herbicide susceptibility that has been identified in some important rice varieties. The newly discovered gene may be useful in breeding new herbicide-resistant crops. Rice is a staple food for more than 3.5 billion people and is among the world's most important crops. To meet the demands of the global food supply, the use of herbicides for controlling weeds is required for efficient crop production. While a useful herbicide is toxic to unwanted plants but harmless to the crop of interest, overuse of individual herbicides can lead to the emergence of weeds resistant to their once-deadly effects. Benzobicyclon (BBC), a beta-triketone herbicide developed for use in rice paddy fields, is effective against paddy weeds resistant to other herbicidal agents. However, BBC is also toxic to several high-yield rice varieties, according to the authors. To identify the gene responsible for BBC resistance or sensitivity, Hideo Maeda and colleagues performed map-based cloning on BBC-resistant and BBC-sensitive rice varieties, and they identified HIS1, a gene that confers resistance to BBC and other beta-triketone herbicides. According to Maeda et al., HIS1 encodes an oxidase that catalyzes and detoxifies BBC compounds. However, susceptible rice varieties inherited a dysfunctional his1 allele and harbor genetic mutations that disable expression of HIS1. What's more, similar functioning genes appear to be widely conserved in other important crop species, suggesting their potential value in breeding new herbicide-resistant crops.

More than 100 years after Albert Einstein published his iconic general theory of relativity, it is beginning to fray at the edges, said Andrea Ghez, UCLA professor of physics and astronomy. Now, in the most comprehensive test of general relativity near the monstrous black hole at the center of our galaxy, Ghez and her research team report July 25 in the journal Science that Einstein's general theory of relativity holds up.

"Einstein's right, at least for now," said Ghez, a co-lead author of the research. "We can absolutely rule out Newton's law of gravity. Our observations are consistent with Einstein's general theory of relativity. However, his theory is definitely showing vulnerability. It cannot fully explain gravity inside a black hole, and at some point we will need to move beyond Einstein's theory to a more comprehensive theory of gravity that explains what a black hole is."

Einstein's 1915 general theory of relativity holds that what we perceive as the force of gravity arises from the curvature of space and time. The scientist proposed that objects such as the sun and the Earth change this geometry. Einstein's theory is the best description of how gravity works, said Ghez, whose UCLA-led team of astronomers has made direct measurements of the phenomenon near a supermassive black hole -- research Ghez describes as "extreme astrophysics."

The laws of physics, including gravity, should be valid everywhere in the universe, said Ghez, who added that her research team is one of only two groups in the world to watch a star known as S0-2 make a complete orbit in three dimensions around the supermassive black hole at the center of the Milky Way. The full orbit takes 16 years, and the black hole's mass is about four million times that of the sun.

The researchers say their work is the most detailed study ever conducted into the supermassive black hole and Einstein's general theory of relativity.

The key data in the research were spectra that Ghez's team analyzed this April, May and September as her "favorite star" made its closest approach to the enormous black hole. Spectra, which Ghez described as the "rainbow of light" from stars, show the intensity of light and offer important information about the star from which the light travels. Spectra also show the composition of the star. These data were combined with measurements Ghez and her team have made over the last 24 years.

Spectra -- collected at the W.M. Keck Observatory in Hawaii using a spectrograph built at UCLA by a team led by colleague James Larkin -- provide the third dimension, revealing the star's motion at a level of precision not previously attained. (Images of the star the researchers took at the Keck Observatory provide the two other dimensions.) Larkin's instrument takes light from a star and disperses it, similar to the way raindrops disperse light from the sun to create a rainbow, Ghez said.

"What's so special about S0-2 is we have its complete orbit in three dimensions," said Ghez, who holds the Lauren B. Leichtman and Arthur E. Levine Chair in Astrophysics. "That's what gives us the entry ticket into the tests of general relativity. We asked how gravity behaves near a supermassive black hole and whether Einstein's theory is telling us the full story. Seeing stars go through their complete orbit provides the first opportunity to test fundamental physics using the motions of these stars."

Ghez's research team was able to see the co-mingling of space and time near the supermassive black hole. "In Newton's version of gravity, space and time are separate, and do not co-mingle; under Einstein, they get completely co-mingled near a black hole," she said.

"Making a measurement of such fundamental importance has required years of patient observing, enabled by state-of-the-art technology," said Richard Green, director of the National Science Foundation's division of astronomical sciences. For more than two decades, the division has supported Ghez, along with several of the technical elements critical to the research team's discovery. "Through their rigorous efforts, Ghez and her collaborators have produced a high-significance validation of Einstein's idea about strong gravity."

Keck Observatory Director Hilton Lewis called Ghez "one of our most passionate and tenacious Keck users." "Her latest groundbreaking research," he said, "is the culmination of unwavering commitment over the past two decades to unlock the mysteries of the supermassive black hole at the center of our Milky Way galaxy."

The researchers studied photons -- particles of light -- as they traveled from S0-2 to Earth. S0-2 moves around the black hole at blistering speeds of more than 16 million miles per hour at its closest approach. Einstein had reported that in this region close to the black hole, photons have to do extra work. Their wavelength as they leave the star depends not only on how fast the star is moving, but also on how much energy the photons expend to escape the black hole's powerful gravitational field. Near a black hole, gravity is much stronger than on Earth.

Ghez was given the opportunity to present partial data last summer, but chose not to so that her team could thoroughly analyze the data first. "We're learning how gravity works. It's one of four fundamental forces and the one we have tested the least," she said. "There are many regions where we just haven't asked, how does gravity work here? It's easy to be overconfident and there are many ways to misinterpret the data, many ways that small errors can accumulate into significant mistakes, which is why we did not rush our analysis."

Ghez, a 2008 recipient of the MacArthur "Genius" Fellowship, studies more than 3,000 stars that orbit the supermassive black hole. Hundreds of them are young, she said, in a region where astronomers did not expect to see them.

It takes 26,000 years for the photons from S0-2 to reach Earth. "We're so excited, and have been preparing for years to make these measurements," said Ghez, who directs the UCLA Galactic Center Group. "For us, it's visceral, it's now -- but it actually happened 26,000 years ago!"

This is the first of many tests of general relativity Ghez's research team will conduct on stars near the supermassive black hole. Among the stars that most interest her is S0-102, which has the shortest orbit, taking 11 1/2 years to complete a full orbit around the black hole. Most of the stars Ghez studies have orbits of much longer than a human lifespan.

Ghez's team took measurements about every four nights during crucial periods in 2018 using the Keck Observatory -- which sits atop Hawaii's dormant Mauna Kea volcano and houses one of the world's largest and premier optical and infrared telescopes. Measurements are also taken with an optical-infrared telescope at Gemini Observatory and Subaru Telescope, also in Hawaii. She and her team have used these telescopes both on site in Hawaii and remotely from an observation room in UCLA's department of physics and astronomy.

Black holes have such high density that nothing can escape their gravitational pull, not even light. (They cannot be seen directly, but their influence on nearby stars is visible and provides a signature. Once something crosses the "event horizon" of a black hole, it will not be able to escape. However, the star S0-2 is still rather far from the event horizon, even at its closest approach, so its photons do not get pulled in.)

In a detailed study of a star orbiting the supermassive black hole at the center of our Galaxy, researchers report that Einstein's theory of general relativity (GR) accurately describes the behavior of light struggling to escape the gravity around this massive structure. The researchers' analysis involved detecting an effect known as "gravitational redshift" in the light emitted by a star closely orbiting the supermassive black hole, as the star was at its closest point to the blackhole in its 16-year orbit. While a similar analysis was conducted by the GRAVITY collaboration last year, here, Tuan Do, Andrea Ghez and colleagues report novel spectra data and expanded analyses. Even as general relativity has been tested in relatively weak gravitational fields, such as those on Earth and in the Solar System, it had not - before last year - been tested around a black hole as big as the one at our Galaxy's center, known as Sagittarius A*. Observations of the stars rapidly orbiting this supermassive black hole would create a method for GR to be evaluated in an extreme gravitational environment. Do, Ghez and colleagues analyzed new observations of the star S0-2 as it made its closest approach to the enormous black hole in 2018. These data were combined with measurements Ghez and her team have made over the last 24 years. The analysis revealed the gravitational redshift, which occurs when light is stretched to longer wavelengths by the gravitational field around the black hole, thereby shifting it towards the red part of the spectrum. The results are consistent with general relativity and substantially favor the theory over Newtonian gravity, which cannot account for the observed redshift. The findings are a "transformational change in our understanding about not only the existence of supermassive blackholes but the physics and astrophysics of black holes," says Ghez in a related video.

The tiny hydra, a freshwater invertebrate related to jellyfish and corals, has an amazing ability to renew its cells and regenerate damaged tissue. Cut a hydra in half, and it will regenerate its body and nervous system in a couple of days. Researchers at the University of California, Davis have now traced the fate of hydra's cells, revealing how three lines of stem cells become nerves, muscles or other tissues.

Celina Juliano, assistant professor in the UC Davis Department of Molecular and Cellular Biology, project scientist Stefan Siebert and colleagues including Jeff Farrell, a postdoctoral researcher at Harvard University, sequenced the RNA transcripts of 25,000 single hydra cells to follow the genetic trajectory of nearly all differentiated cell types.

"The beauty of single-cell sequencing and why this is such a big deal for developmental biologists is that we can actually capture the genes that are expressed as cells differentiate from stem cells into their different cell types," Juliano said.

The study gives developmental biologists a high-resolution map of the three stem cell developmental lineages in hydra. The data set will help researchers understand regulatory gene networks in place early in evolution that are shared among many animals, including humans, Siebert said. Understanding how the hydra regenerates its entire nervous system, for example, could help us better understand neurodegenerative diseases in humans.

Regenerates from three lines of stem cells

Hydra continuously renew their cells from three different stem cell populations. The researchers analyzed sets of messenger RNA molecules, called transcriptomes, from individual hydra cells and grouped the cells based on their expressed genes. They could then build a decision tree showing how each lineage of stem cells gives rise to different cell types and tissues. For example, the interstitial stem cell lineage produces nerve cells, gland cells and the stinging cells in the animal's tentacles.

"By building a decision tree for the interstitial lineage, we unexpectedly found evidence that the neuron and gland cell differentiation pathway share a common cell state," said Juliano. "Thus, interstitial stem cells appear to pass through a cell state that has both gland and neuron potential before making a final decision."

The single cell molecular map also allowed Juliano and colleagues to identify genes that may control these decision-making processes, which will be the focus of future studies.

Researchers are especially interested in hydra's ability to regenerate its nervous system, which could give insights into treating trauma or degenerative disease in humans.

"All organisms share the same injury response pathway but in some organisms like hydra, it leads to regeneration," said coauthor and graduate student Abby Primack. "In other organisms, like humans, once our brain is injured, we have difficulty recovering because the brain lacks the kind of regenerative abilities we see in hydra."

The U.S. Centers for Disease Control and Prevention (CDC) recently developed an Autocidal Gravid Ovitrap (AGP trap) that attracts and captures female mosquitos looking for a site to lay eggs. Now, researchers writing in PLOS Neglected Tropical Diseases report that AGO traps successfully protected people from infection with chikungunya virus (CHIKV) in communities in Puerto Rico.

The lack of effective tools to control Aedes aegypti mosquito populations has resulted in the continued expansion of dengue virus, Zika virus and CHIKV. Some recent attempts at curbing mosquito populations have resulted in reductions in mosquito density but not reductions in human disease. AGO traps consist of a pail with hay and water to attract egg-bearing female mosquitos and a sticky lining to which the insects adhere. Previous studies have shown that placing three AGO traps outside of 85% of homes in a community resulted in an 80% reduction in adult mosquito populations but the studies did not assess rates of mosquito-borne diseases in humans.

In the new work, Tyler Sharp, of the CDC, and colleagues randomly selected 290 households in Puerto Rican communities that had AGO trap interventions and 349 households in communities without AGO traps. 175 household members from intervention communities and 152 from non-intervention communities were enrolled in the study. Blood samples were collected from each participant to detect CHIKV infection and surveys recorded demographic information as well as data on mosquito repellant and bed net use and frequency of mosquito bites.

A total of 114 participants (34.9%) were seropositive for CHIKV. Among people who spent most of their daytime hours inside the community they lived in, 10.3% were seropositive for CHIKV in communities with AGO traps whereas 48.7% were positive for CHIKV in communities without traps. Among all participants, including those who did not spend as much daylight time within the community, 26.1% were seropositive for CHIKV in the intervention communities and 43.8% were positive in communities without traps.

"AGO traps are a novel chemical-free, effective approach to control Ae. aegypti populations and provide protection from infection with the pathogens that these mosquitos transmit," the researchers say. "Further evaluations should determine if AGO traps are sustainable and effective in larger scale community trials."

In a groundbreaking new study published in the journal Nature, an international team of over 150 scientists from 26 countries combined movement data from nearly 2,000 sharks tracked with satellite tags. Using this tracking information, researchers identified areas of the ocean that were important for multiple species, shark "hot spots", that were located in ocean frontal zones, boundaries in the sea between different water masses that are highly productive and food-rich. Researchers then calculated how much shark hotspots overlapped with global longline fishing vessels - the type of fishing gear that catches most open-ocean sharks. The study found that 24% of the space used by sharks in an average month falls under the footprint of longline fishing. For commercially exploited sharks such as blue and shortfin makos sharks in the North Atlantic, the overlap was much higher, with on average 76% and 62% of their space use, respectively, overlapping with longlines each month. Even internationally protected species, such as great whites, had over 50% overlap with longline fleets. 

"Our results show major high seas fishing activities are currently centered on ecologically important shark hotspots worldwide" says Professor David Sims, who led the study as part of the Global Shark Movement Project based at the Marine Biological Association Laboratory in Plymouth, UK.

Equally alarming was that shark hotspots showing high overlap with longline fishing were often also subjected to high fishing effort, a potential 'double whammy' for sharks that will result in higher catch rates and potentially accelerate declines in abundance.  

"Some shark hotspots were exposed to higher than average fishing effort for as much as half the year" said Nuno Queiroz, a lead researcher in the study from the University of Porto in Portugal.

The team's findings indicate large sharks - some of which are already endangered globally - face a future with limited spatial refuge from industrial longline fishing effort.

"Currently, little to no protection exists for sharks in the high seas. It's clear from our study that immediate conservation action is needed to prevent further declines of open-ocean sharks," said Neil Hammerschlag, a study co-author and research associate professor at the University of Miami Rosenstiel School of Marine and Atmospheric Science. "These finding are concerning because as top predators, sharks help maintain healthy ocean ecosystems," said Hammerschlag. 

Hammerschlag provided data from 154 tagged sharks of 10 species which included blacktip, blue, bull, Mako, scalloped hammerhead, sandbar, silky and tiger.

The researchers propose that designated large-scale marine protected areas around regions of shark activity could be one solution. The study suggests that the detailed maps of shark hotspots overlapping with longline fishing provide a 'blueprint' for deciding where to place large-scale marine protected areas (MPAs) aimed at conserving sharks, in addition to the need for strict quotas to reduce catches elsewhere. 

"Some of the shark hotspots we studied may not be there in as little as a few years' time if management measures are not put in place now to conserve the sharks and the habitats on which they depend" Sims says.

The research was published online in Nature on 24th July 2019, Global spatial risk assessment of sharks under the footprint of fisheries.  doi: 10.1038/s41586-019-1444-4

WASHINGTON (July 25, 2019) - Nearly 1,200 child care programs in ten states have improved their healthy eating and physical activity standards after participating in Nemours Children's Health System's National Early Care and Education Learning Collaboratives (NECELC) project, funded by the Centers for Disease Control and Prevention. The results, published today in the journal Preventing Chronic Disease, show broad and sustainable improvements in best practices reported by child care programs through targeted state-based efforts emphasizing learning from other child care providers, making changes within their centers, and technical assistance.

"Promotion of healthy eating and physical activity in child care settings has potential to reduce obesity risk among the one in four children under the age of five who spend some part of their week in child care," said Debbie I. Chang, MPH, Nemours' senior vice president of policy and prevention and an author of the study. "Recently reported declines in obesity in these young children offer early support of efforts targeting this age group."

The NECELC project was a multi-sector approach to embed best practices in healthy eating and physical activity in early care and education (ECE) settings. Researchers said the six-year project was important because 13 million children spend time in ECE, and more than one of eight children (14%) ages 2 to 5 have obesity. The best practices focus on five areas: infant feeding, child nutrition, physical activity, outdoor play and learning, and screen time.

The program reached children in Alabama, Arizona, California, Florida, Indiana, Kansas, Kentucky, Missouri, New Jersey, and Virginia. While Nemours provided guidance and direction regarding implementation, each state's designated implementing partner had flexibility for tailoring the model at the state, local, and program level to have the biggest impact.

The 10-month program was spread and scaled to more than 1,910 ECE programs (1,173 programs participated in the evaluation phase) from 2012 through 2017 and included pre- and post- program assessments, peer learning sessions for program leaders and staff, action planning and implementation, and technical assistance. In addition to this support, each participating program received a $500 stipend to incentivize their participation.

The project team measured the number of self-reported healthy eating and physical activity best practices among programs serving only preschoolers, toddlers and infants at the start and end of the program. The number of best practices met in each of the five areas increased significantly during the assessment period. Improvement was highest for outdoor play and learning, where an additional 2.4 best practices represented a 44 percent improvement. It was lowest for child nutrition, where an additional 4.7 best practices was a 20 percent improvement. The authors note that programs may have had more opportunities for improving best practices in outdoor play and learning, while many ECE programs were already meeting many child nutrition best practices at the start of their involvement in the project.

"The reproducibility of results across states, and across well-resourced and poorly resourced child care programs support that this model allowed, as intended, for optimal tailoring at the state, local, and program level," said Chang. "We believe this approach may help fill a gap in resources, educational materials, and setting standards among early childhood programs."

A video related to the research can be downloaded here.

A call for a change in the law to class men, forced to have sex with women, as rape victims has been made in a new study by Lancaster University researchers published today.

Men have added their voices to a ground-breaking study - the first of its kind to interview men in the UK - which examines their experience of non-consensual sex with women (known as 'forced to penetrate' cases or FTP).

The term 'forced-to-penetrate' has been coined for these cases because, while they involve non-consensual sex, they do not fall under the offence of rape.

The majority of participants interviewed in the study labelled their forced to penetrate (FTP) experiences as rape, even though this is not reflected in current UK laws.

Reform of sexual offences legislation was important to participants to ensure male survivors' experiences were appropriately acknowledged and labelled.

The study, funded by the British Academy, also found:

Men were often repeatedly victimised with, for example, repeated instances of being FTP the same/different women, childhood sexual abuse, and varying types of sexual violence.

Victims most frequently reported the crime was committed by their female partner or ex-partner and their FTP experiences were one element of domestic abuse or post separation abuse

The fear of not being believed, and feelings of guilt and self-blame were identified as key barriers to men disclosing they had been forced to have sex with women

Men forced to have sex with women were likely to experience significant mental health issues, including depression, anxiety, and suicidal thoughts, and often took several years to disclose their experiences to anyone or to seek help and support

The majority of participants in the research did not report the crime to the police and, of those who did, most had negative experiences

Participants had 'overwhelmingly negative perceptions' of the police, criminal justice system, and the law

The in-depth study, which breaks the silence around men being sexually violated by women has been published by a research team led by Dr Siobhan Weare, of Lancaster University Law School, in partnership with Survivors Manchester.

The study 'Experiences of men forced-to-penetrate women in the UK: Context, consequences and engagement with the criminal justice system' focused on the experiences of 30 men who took part in in-depth interviews and shared their stories.

The study builds on research already undertaken in this area by Dr Weare who, in 2016, conducted an online survey around forced-to-penetrate cases which was completed by more than 150 men.

The study calls for:

Legal reform

The introduction of a national strategy to end intimate violence against men and boys. Currently this is only a footnote in a national strategy focused on women and girls

Clearer recognition of men's experiences of sexual violence perpetrated by women with properly signposted support services and specialist training for police officers, social workers, therapists, and counsellors.

"These new findings have provided a far greater insight and understanding about this 'hidden crime'," said Dr Weare.

"These men were incredibly brave sharing their stories. By 'breaking their silence', we hope that the findings from this research study can help to shape policy and practice in this area.

"This is a hugely under-discussed issue and so services must make sure that their staff are trained appropriately to support male survivors. We must also make sure that this issue is adequately and accurately addressed in national policies and law.

"That is why we are calling for law reform in this area and the introduction of a national 'Ending Intimate Violence Against Men and Boys' strategy."

Examples of FTP circumstances might include:

A man waking up to find a woman having sex with him without his consent.

A man being forced to have non-consensual sex with a woman as a result of her blackmailing him.

A man having non-consensual sex with a woman after being physically, emotionally, or financially threatened.

Dr Weare launched her research findings today at a knowledge exchange event attended by academics and practitioners, including Third Sector service providers, NHS and other health professionals and the Crown Prosecution Service.

ITHACA, NY, July 22, 2019 - Protecting crops from pests and pathogens without using toxic pesticides has been a longtime goal of farmers. Researchers at Boyce Thompson Institute have found that compounds from an unlikely source - microscopic soil roundworms - could achieve this aim.

As described in research published in the May 2019 issue of Journal of Phytopathology, these compounds helped protect major crops from various pathogens, and thus have potential to save billions of dollars and increase agricultural sustainability around the world.

Led by BTI Senior Research Associate Murli Manohar, a team around Professors Daniel Klessig and Frank Schroeder investigated the effects of a roundworm metabolite called ascr#18 on plant health.

Ascr#18 is a member of the ascaroside family of pheromones, which are produced by many soil-dwelling species of roundworms for chemical communication.

The researchers treated soybean (Glycine max), rice (Oryza sativa), wheat (Triticum aestivum) and maize (Zea mays) plants with small amounts of ascr#18, and then infected the plants with a virus, bacteria, fungus or oocmycete.

When examined several days later, the ascr#18-treated plants were significantly more resistant to the pathogens compared with untreated plants.

"Plant roots are constantly exposed to roundworms in the soil, so it makes sense that plants have evolved to sense the pest and prime their immune systems in anticipation of being attacked," says Schroeder.

Because they boost plants' immune systems instead of killing pests and pathogens, ascarosides are not pesticides. As a result, they are likely to be much safer than many current means of pest and pathogen control.

"Ascarosides are natural compounds that appear to be safe to plants, animals, humans and the environment," says Klessig. "I believe they could thus provide plants more environmentally friendly protection against pests and pathogens."

In previous work, Klessig and Schroeder demonstrated that ascr#18 and other ascarosides increased resistance against pest and pathogens in tomato, potato, barley and Arabidopsis.

"By expanding the work to major crops, and concentrating on their most significant pathogens, this study establishes the potential for ascarosides to enhance agriculture production worldwide," says Klessig.

Indeed, rice is the world's most important staple food for nearly half of the global population. Ascr#18 provided protection against Xanthomonas oryzae pv. oryzae, a bacterium that causes yield losses of 10-50% in Asian countries.

Wheat is close behind rice in importance as a food staple, and ascr#18 protected it against Zymoseptoria tritici, a fungus that is one of the most severe foliar diseases of the crop.

Maize is the most widely grown grain crop throughout the Americas with great importance for food, biofuel and animal feed. Ascr#18 provided protection against Cochliobolus heterostrophus, a fungal pathogen that causes southern corn leaf blight.

Soybean is a major high-protein, oil-rich seed crop used as a food source for humans and animals. Ascr#18 protected soybeans against Phytophthora sojae, an oomycete that can kill infected plants in days, as well as the bacterial pathogen Pseudomonas syringae pv glycinea and Soybean Mosaic Virus.

Extremely small concentrations of ascarosides are sufficient to provide plants with resistance against pathogens. Interestingly, the optimal concentration appears to be dependent on the plant species and not the pathogen.

The researchers believe the reason that different plant species have different optimal dosages is likely related to the plant cell's receptors for ascr#18. Different plant species may express different amounts of ascr#18 receptors, and receptors may have varying affinities for ascarosides. Such differences would affect the amount of ascr#18 needed to trigger the plant's immune systems.

The group is now working to determine the molecular mechanisms of how ascarosides prime the plant's immune systems.

These discoveries are being commercialized by a BTI and Cornell-based startup company, Ascribe Bioscience, as a family of crop protection products named PhytalixTM.

"This work is a great example of how the Institute is leveraging our technology through new start-up ventures, an important strategic initiative at BTI," says Paul Debbie, BTI's Director of New Business Development. "The Institute is proud of the opportunity to develop innovative technology in partnership with a new company that is having a positive economic impact here in our local community and for New York State."

Research has long indicated that the elimination of the North American Free Trade Agreement (NAFTA), or simply the withdrawal of the U.S. from NAFTA, would reduce standards of living in Canada, Mexico and the U.S.

A new study from the University of Notre Dame shows the move would indeed economically hurt all three countries, but with a surprising twist -- Canada would suffer the most.

Typically, the smallest economy -- in the case of NAFTA, Mexico -- loses the most in per capita income because smaller economies tend to rely more on international trade, but not here, according to the study, "Putting Canada in the Penalty Box: Trade and Welfare Effects of Eliminating NAFTA," forthcoming in The World Economy by Jeffrey Bergstrand, professor of finance in Notre Dame's Mendoza College of Business.

"When a free trade agreement is eliminated, tariffs between the former members rise," Bergstrand explains. "With NAFTA, as each country's tariffs rise, it makes goods in non-member countries cheaper to buy and export. And it makes goods at home relatively less expensive. However, the fall in members' trade does reduce demand in each country and lowers wage rates in all the countries, which we found. It also -- due to higher tariffs among the former members -- raises prices in all the countries, which we also found. This is what lowers standards of living."

The study's determination that Canada's standard of living fell the most is due to the economic and geographic structure of the Canadian economy.

"As some of Canada's trade with the U.S. and Mexico is diverted to its own economy, that new intra-national or domestic economic activity in Canada is much more expensive," Bergstrand says. "Canada's population is much more dispersed, which increases the costs of trading within the Canadian borders. Canada's population is one-tenth that of the U.S., but its geographic area is three times its size. Canada's area is five times that of Mexico, and one may argue that Canada's economic activity is heavily concentrated in adjacent provinces of Ontario and Quebec; however, half of Mexico's GDP is generated among three cities that are all within 450 miles of one another. Also, Mexico has one common language for transactions, while Canada is prominently bilingual, which historically raises costs of doing business."

Bergstrand used a standard New Quantitative Trade Model of international trade, paying particular attention to capturing carefully and completely the international trade costs between nations as well as the intra-national trade costs within each country. Such models have been increasingly employed since 2016 to analyze Brexit (the withdrawal of the United Kingdom from the European Union).

"Canada's per capita income loss of 2.11 percent is nearly two times that of Mexico's loss of 1.15 percent and nearly eight times the United States' loss of 0.27 percent," Bergstrand says, "illustrating the important influence of trade costs -- both international and intra-national -- in contributing to the gains or losses from an economic integration agreement's formation or elimination."

NAFTA is at risk if the U.S. withdraws, which President Donald Trump has threatened to do if his new trade deal -- the United States-Mexico-Canada Agreement -- is not passed by Congress.

Last year, Bergstrand testified before the International Trade Commission on the documented benefits of free trade agreements, including boosts to trade and economic welfare.

Bergstrand is a research associate of CESifo, an international network of researchers based in Europe. His research has been published in more than 50 articles and book chapters. He has served as a visiting scholar at the European Commission in Brussels, the Ifo Institute/University of Munich, ETH University in Zurich and several other institutions.

Co-authors of the study include Scott Baier at Clemson University and John Bruno at Cornerstone Research (also a Notre Dame graduate).

WACO, Texas (July 25, 2019) - Supervisors driven by profits could actually be hurting their coveted bottom lines by losing the respect of their employees, who counter by withholding performance, according to a new study led by Baylor University.

The study, "The Influence of Supervisor Bottom-Line Mentality and Employee Bottom-Line Mentality on Leader-Member Exchange and Subsequent Employee Performance," is published in the journal Human Relations.

"Supervisors who focus only on profits to the exclusion of caring about other important outcomes, such as employee well-being or environmental or ethical concerns, turn out to be detrimental to employees," said lead researcher Matthew Quade, Ph.D., assistant professor of management in Baylor University's Hankamer School of Business. "This results in relationships that are marked by distrust, dissatisfaction and lack of affection for the supervisor. And ultimately, that leads to employees who are less likely to complete tasks at a high level and less likely to go above and beyond the call of duty."

While other studies have examined the impact of bottom-line mentality (BLM) on employee behavior, Quade said this is the first to identify why employees respond with negative behaviors to supervisors they perceive to have BLM.

The research team surveyed 866 people. Half of those surveyed were supervisors; the other half were their respective employees. Data was collected from those who work in a range of jobs and industries, including financial services, health care, sales, legal and education.

Researchers measured supervisor BLM, employee BLM, task performance and leader-member exchange - the rating employees gave of their relationships with their supervisors.

Employees rated their supervisors' BLM by scoring on a scale statements like: "My supervisor treats the bottom line as more important than anything else" and "My supervisor cares more about profits than his/her employees' well-being." They rated leader-member exchange via statements such as "I like my supervisor very much as a person" and "My relationship with my supervisor is composed of comparable exchanges of giving and taking."

Supervisors rated their employees by scoring statements such as: "This employee meets or exceeds his/her productivity requirements," "This employee searches for ways to be more productive" and "This employee demonstrates commitment to producing quality work."

Based on the responses and the data collected and analyzed, the researchers found:

High-BLM supervisors create low-quality relationships with their employees.

In turn, employees perceive low-quality leader-member exchange relationships.

Thus, employees reciprocate by withholding performance.

When supervisor BLM is high and employee BLM is low, the damaging effects are strengthened.

When both supervisor and employee BLM are high, the negative performance is still evident.

The last finding on that list was particularly significant, Quade said, because it contradicts a common belief that when two parties (in this case, supervisors and employees) think alike and have similar values, there will be a positive outcome. Not so much in the case of BLM, the study shows.

"When supervisor and employee BLM is similarly high, our research demonstrates the negative effect on performance is only buffered, not mitigated - indicating no degree of supervisor BLM seems to be particularly beneficial," the researchers wrote. "It seems even if employees maintain a BLM, they would prefer for their managers to focus on interpersonal aspects of the job that foster healthier social exchange relationships with their employees in addition to the bottom line."

The profit-performance relationship can spark a conundrum for companies, Quade said, because organizations want to be profitable, and performance is an important indicator of an organization's health and vitality.

If leaders believe a negative dynamic regarding BLM exists in their organization, the researchers suggest a few practical steps:

Be cautious of a BLM approach or emphasizing bottom-line outcomes that could neglect other organizational concerns, such as employee well-being and ethical standards.

Managers should be aware of the message they pass along to employees (and the possible performance repercussions) when they tout bottom-line profits as the most important consideration.

Organizations that need to emphasize bottom-line outcomes should consider pairing the BLM management style with other management approaches known to produce positive results, such as practicing ethical leadership.

"Supervisors undoubtedly face heavy scrutiny for the performance levels of their employees, and as such they may tend to emphasize the need for employees to pursue bottom-line outcomes at the exclusion of other competing priorities, such as ethical practices, personal development or building social connections in the workplace," the researchers wrote. "However, in doing so they may have to suffer the consequence of reduced employee respect, loyalty and even liking."

After nerve injury, the protein complex mTORC1 takes over an important function in skeletal muscle to maintain the neuromuscular junction, the synapse between the nerve and muscle fiber. Researchers at the University of Basel's Biozentrum have now shown that the activation of mTORC1 must be tightly balanced for a proper response of the muscle to nerve injury. The study published in Nature Communications opens new insights into muscle weakness related to neuromuscular diseases or caused by ageing.

The protein complex mTORC1 promotes muscle growth and is important for the self-cleaning process of the muscle cells. The role of mTORC1 in skeletal muscle fibers in response to nerve injury has so far not been studied in detail. New insights have been provided by the research team led by Markus Rüegg at the Biozentrum of the University of Basel.

Function of mTORC1

Nerves and muscles in our body are connected by specialized synapses, called neuromuscular junctions, which transmit signals from the nerve to muscle fibers. If innervation is lost or interrupted by the injury of the nerve, muscles cannot contract anymore. However, to prepare the muscle for re-innervation by the nerve, the muscle component of the neuromuscular junction, the motor endplate, is maintained. Rüegg's research team has now more closely studied the function of mTORC1 and its upstream kinase PKB/Akt in the maintenance of the motor endplate after nerve injury using different mouse models.

The best known function of the PKB/Akt - mTORC1 signaling pathway is to promote muscle growth and the cellular self-cleaning process. &laquoWe have now been able to show that PKB/Akt and mTORC1 also play an important role in the maintenance of the neuromuscular endplate», explains Perrine Castets, first author of the study.

PKB/Akt - mTORC1 tightly balanced

After nerve damage, both PKB/Akt and mTORC1 get activated in muscle fibers. Rüegg's study demonstrates that mTORC1 should not be activated too strongly nor too little to ensure a proper response of the muscle. The underlying mechanism involves an mTORC1-dependent feedback onto the kinase PKB/Akt: &laquoShould mTORC1 be too strongly activated, PKB/Akt is inhibited, resulting in the loss of the neuromuscular endplate. Balanced activation of both PKB/Akt and mTORC1 is required for the proper response of the muscle fiber», says Castets.

The newly described function of PKB/Akt and mTORC1 opens new perspective on how age-related muscle atrophy develops in humans. This is, likewise, induced through an alteration of neuromuscular endplates and possibly by over-activation of mTORC1. &laquoThrough this study, we now better understand the molecular mechanisms contributing to the maintenance of the neuromuscular junctions. Based on our results, we may be able to develop new approaches to potentially counteract age-related deficits and structural changes in order to better preserve the performance and functional capabilities of the muscles during ageing», says Rüegg.

Pufferfish are known for their strange and extreme skin ornaments, but how they came to possess the spiky skin structures known as spines has largely remained a mystery. Now, researchers have identified the genes responsible for the evolution and development of pufferfish spines in a study publishing July 25 in the journal iScience. Turns out, the process is pretty similar to how other vertebrates get their hair or feathers--and might have allowed the pufferfish to fill unique ecological niches.

"Pufferfish are some of the strangest fish in the ocean, particularly because they have a reduced skeleton, beak-like dentition and they form spines instead of scales--not everywhere, but just in certain patches around the body," says corresponding author Gareth Fraser (@garethjfraser), an Assistant Professor at the University of Florida.

Fraser and his team followed the development of pufferfish spines in embryos. While they had initially hypothesized that the spines formed from scales--that the pufferfish lost its scale component but retained the spine--they found that the spines are developmentally unique from scales. They also found that the development of pufferfish spines relies on the same network of genes that are commonly expressed within feathers and hairs of other vertebrate animals.

"It just blows me away that regardless of how evolutionarily-different skin structures in animals are, they still use the same collection of genes during development," Fraser says.

The researchers then decided to look at what would happen if they manipulated those genes. Using CRISPR-Cas9 and other genetic techniques, the researchers blocked particular genes that are classic markers of skin appendage development. Doing so allowed them to reduce the number of spines on pufferfish, as well as loosen the restriction on where the spines appear on the pufferfish.

Normally, the spines are localized to specific areas on the pufferfish. Fraser says that this localization of the spines is to enhance protection.

"When pufferfish inflate by ingesting water or in some cases air, their skin becomes stretched, especially around the abdomen and is more susceptible to damage, such as being torn," he says. "Spines reinforce the puffed-up abdomen. In extreme cases, some pufferfish have lost all other spines on their body and retain only the abdominal spines."

The reason for the diversity in spine coverage is likely ecological, Fraser says.

"What really drives these changes, in terms of loss or gain of spines, is multifactorial, but the shifts in spine coverage and morphology may allow pufferfish to take advantage of new ecological niches that are available to them," he says. "As the climate changes and environments become different, pufferfish may use these evolving traits to tolerate and adapt to change."

Through their sequencing efforts, Fraser and his colleagues hope to ultimately identify the differences in the genome that allow for the diversity in spine coverage, morphology and the transition from scales to spines.

"We can manipulate different things associated with pufferfish diversity, which gives us clues about the function of genes that are necessary for normal development and helps us understand the evolution and patterns of pufferfish spines," Fraser says. "Pufferfish are wildly-derived fish that are incredibly different from other groups, and ultimately, we want to see if there's something specific to the genome of the pufferfish that can provide clues to suggest mechanisms that allow them to create these weird structures."

Human artificial chromosomes (HACs) could be useful tools for both understanding how mammalian chromosomes function and creating synthetic biological systems, but for the last 20 years, they have been limited by an inefficient artificial centromere. In the journal Cell on July 25th, researchers announce that they have made progress on this key component.

"The centromere used to be called the black box of the chromosome," says Ben Black, professor of biochemistry and biophysics at the University of Pennsylvania. "If you're studying any kind of biological process, you want to be able to build it, and that's where we've made progress here."

In mammals, centromeres--the central point of the X-shaped chromosome--ensure that a chromosome is inherited when a cell divides, acting as an anchor for the spindle fibers that pull the duplicated chromosome in half. The genetic sequence of a natural human centromere is thousands of repetitions of a 171-base-pair sequence. Centromeric DNA must also be modified epigenetically in the cell to function properly. These epigenetic marks (protein and chemical tags along the DNA) are thought to be established at centromeres by the human CENP proteins.

First-generation HACs have relied on both the repetitive centromere sequence and CENP-B. But the repetitive sequence make centromeres tricky to clone for study in the lab. Therefore, "all of the synthetic chromosomes that have been recently reported use approaches that intentionally remove repetitive elements," Black says, making it so far impossible to transition the techniques that work in yeast artificial chromosomes to HACs.

Black's team has now created two new HACs: neither use CENP-B, and one is not repetitive. "We wanted to see if we can break the rules by bestowing the DNA we put into the cell with epigenetic markers from the get go," says Black. Their improvements remove the requirement for CENP-B, make the HACs more reliably inherited in cell culture, and provided the opportunity for the researchers to study them with genomic approaches, which had previously been impossible.

CENP-B, though not essential for natural chromosomes, has been assumed to be required for artificial centromere formation until now. A closely related protein, CENP-A, is actually the essential epigenetic marker for centromeres, and Black and his team have been able to direct the assembly of CENP-A onto the incoming HAC DNA.

The next-generation HACs made by Black and his team will allow for more thorough study of the essential components of functional chromosomes. Because a version of their HAC does not have the long repeating section, Black's team was able to use genomic approaches to analyze the sequence where centromeres formed. More reliable HACs will also open the door to complex synthetic biological systems that require longer sequences than can fit in viruses, the current common mode of delivering synthetic genetic systems.

WASHINGTON, July 25, 2019 -- Your body is a delicately balanced chemical system, and if you take too much of a drug, you destroy that balance. That's what happens when you overdose. This week on Reactions, learn how to spot an overdose and the ways different types of drugs wreak havoc on your brain: https://youtu.be/xLSz3wEgwJ8.