Earth

Rats take a fundamentally different approach toward solving a simple visual discrimination task than tree shrews, monkeys, and humans, according to a comparative study of the four mammal species published in eNeuro. The work could have important implications for the translation of research in animal models to humans.

Scientists have developed powerful technologies that allow for precise manipulation of the rodent nervous system, which is similar to that of humans, making them crucial laboratory animals in neuroscience. Although it is thought that learning in mice and rats can overcome initial species differences on a task, few studies have directly tested this idea.

Gregor Rainer and colleagues addressed this gap in knowledge by comparing the ability of two species more closely related to humans -- macaques (Macaca fascicularis) and tree shrews (Tupaia belangeri) -- to discriminate a flickering light from two distracting stimuli. While the macaques and tree shrews used similar visual learning strategies and their performance improved over time, rats (Rattus norvegicus) were instead focused on where they had previously received a food reward and their performance did not improve. These findings suggest that rats use their brains differently than the other species in the context of this particular task.

The ability to obtain new memories in adulthood may depend on neurogenesis -- the generation of new neurons in the hippocampus -- to clear out old memories that have been safely stored in the cortex, according to research in male rats published in JNeurosci.

Previous research suggests that the hippocampus has a finite capacity to acquire and store new memories. It is unknown how the brain compensates for this limitation to facilitate learning throughout life.

Kaoru Inokuchi and colleagues show that reducing neurogenesis in rats impairs recovery of learning capacity while promoting neurogenesis through physical activity on a running wheel increased hippocampal capacity. This finding implies that neurogenesis, which can be reduced by stress and aging, underlies the brain's capacity for new memories. The study may also explain why exercise is especially important for patients with memory disorders such as Alzheimer's disease as well as for healthy people to help maintain memory as they age.

Chicago, IL - A new study published in Pediatrics found that young adults who had a parent incarcerated during their childhood are more likely to skip needed healthcare, smoke cigarettes, engage in risky sexual behaviors, and abuse alcohol, prescription and illicit drugs. These findings have potentially broad impact, as over five million U.S. children have had a parent in jail or prison.

Strikingly, incarceration of a mother during childhood, as opposed to a father, doubled the likelihood of young adults using the emergency department instead of a primary care setting for medical care.

Young adults whose mothers had been incarcerated also were twice as likely to have sex in exchange for money, while those with histories of father incarceration were 2.5 times more likely to use intravenous drugs.

"The United States has the highest incarceration rates in the world. With the climbing number of parents, especially mothers, who are incarcerated, our study calls attention to the invisible victims - their children," says lead author Nia Heard-Garris, MD, MSc, a pediatrician at Ann & Robert H. Lurie Children's Hospital of Chicago and Instructor of Pediatrics at Northwestern University Feinberg School of Medicine. "We shed light on how much the incarceration of a mother versus father influences the health behaviors of children into adulthood."

Dr. Heard-Garris and colleagues analyzed national survey data from over 13,000 young adults (ages 24-32), finding that 10 percent have had a parent incarcerated during their childhood. Participants were on average 10 years old the first time their parent was incarcerated.

Additionally, young Black adults had a much higher prevalence of parental incarceration. While Black participants represented less than 15 percent of the young adults surveyed, they accounted for roughly 34 percent of those with history of an incarcerated mother and 23 percent with history of an incarcerated father.

"The systemic differences in the arrest, prosecution, conviction, and sentencing of people of color impact the future health of their children," says Dr. Heard-Garris.

Previous research shows that individuals with a history of parental incarceration have higher rates of asthma, HIV/AIDS, learning delays, depression, anxiety and post-traumatic stress disorder.

"It's possible that because these young adults are more likely to forgo medical care and engage in unhealthy behaviors, they are at higher risk to develop these physical and mental health conditions," says Dr. Heard-Garris. "By pinpointing the specific health-harming behaviors that these young adults demonstrate, this study may be a stepping stone towards seeking more precise ways to mitigate the health risks these young adults face. Hopefully, future studies will teach us how to prevent, screen for, and target negative health behaviors prior to adulthood."

The authors also stress that more research is needed to identify specific barriers to healthcare, targeting this population's under-utilization of care.

"We need to consider how to help youth of incarcerated parents receive timely healthcare," says senior author Matthew Davis, MD, MAPP, Senior Vice-President and Chief of Community Health Transformation at Lurie Children's and Professor of Pediatrics, Medicine, Medical Social Sciences and Preventive Medicine at Northwestern University Feinberg School of Medicine. "We must intervene if we are going to change the health trajectories for these kids."

Sea levels in coastal areas can be affected by a number of factors: tides, winds, waves, and even barometric pressure all play a role in the ebb and flow of the ocean. For the first time, however, a new study led by the Woods Hole Oceanographic Institution (WHOI) has shown that river outflow could play a role in sea level change as well.

The study, published July 9 in the journal Proceedings of the National Academy of Sciences, examined decades' worth of river level and tidal data from gauges installed throughout the eastern United States. The researchers then combined that data with information on water density, salinity, and the Earth's rotation, creating a mathematical model that describes the link between river discharge and sea level on an annual basis.

"The equation we derived lets us predict how much sea level will rise based on river flow, and then compare that prediction to actual measurements and observations," says Chris Piecuch, a physical oceanographer at WHOI and lead author on the paper. "Based on our model and the observations, we're finding that variations in the amount of water that comes out of a river annually can raise or lower coastal mean sea level by several centimeters."

Notably, the study found the majority of that sea level change occurs only one side of a river's mouth. Since freshwater is naturally less dense than saltwater, river outflow floats along the ocean's surface, where the Earth's rotation forces it to turn sharply along the coast. In the northern hemisphere, that water follows the right hand side of the river; in the southern hemisphere, the left hand side. In both cases, the freshwater forms a current that pushes water up against the shoreline, raising localized sea levels in the process.

At the moment, says Piecuch, the model is still just a proof-of-concept, but could already help calculate the effects of sea level rise on certain coastal regions. That data is missing from current satellite measurements, since the resolution of existing sensors isn't fine enough to get accurate readings of ocean height within a few miles of the coast.

"When you think of societal impact, you want to know what's happening at the coast," Piecuch says. "In low lying areas like Bangladesh, we don't yet know how sea level and river outflow combine. But if a major storm comes through, even a small rise in the background mean sea level could have a huge impact on flooding."

Right now, the WHOI model has only been used to calculate average sea level on an annual basis--but Piecuch and his colleagues are working to change that. Ultimately, they hope to consider more detailed and granular data, so they can understand how individual events, like a hurricane or massive rainfall, might affect ocean levels.

"Many processes can affect sea level, making predictions of regional sea level change a challenging endeavor," says Larry Peterson, a program director in the National Science Foundation (NSF)'s Division of Ocean Sciences, which funded the research. "These scientists show that discharge from rivers can play a significant but overlooked role in the interpretation of sea level from downstream tide gauges. The work has important implications for climate models, remote sensing, and the projection of coastal flood risks."

A new study reveals that individuals younger than 50 years of age who are diagnosed with rectal cancer do not experience an overall survival benefit from currently recommended treatments. Specifically, the addition of chemotherapy and radiation to surgery does not prolong life for these patients. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the findings suggest that early onset disease may differ from later onset disease in terms of biology and response to therapy.

The overall incidence of rectal cancer is decreasing in patients older than 50 years of age, likely due to improved screening adherence; however, there is a disproportionate increase in rectal cancer incidence in patients under the age of 50 years. In addition, the mortality rate from rectal cancer among younger patients has increased in the past several decades.

Current national guidelines--which recommend a combination of chemotherapy, radiation, and surgery for stages II and III rectal cancer--are predominantly based on data from patients older than 50 years of age. To examine how younger patients fare, a team led by Atif Iqbal, MD, of the University of Florida College of Medicine, in Gainesville, examined 2004-2014 information from the National Cancer Database. A total of 52,519 patients were analyzed.

The team found that patients younger than 50 years old who have been diagnosed with rectal cancer represent a unique group. These younger patients do not see a survival benefit from receiving the currently recommended treatment for stages II and III rectal cancer.

"Our findings support the notion that rectal cancer in young patients may be biologically different from older patients, with differing response to treatment, as has been previously shown in colon cancer," said Dr. Iqbal. "These findings may help stimulate future research trial proposals focused on the younger patient population."

The study also reveals age-specific survival data for younger patients. "These data provide practicing physicians the ability to offer a prognosis personalized to the younger population, which can greatly improve discussions with younger patients."

In an accompanying editorial, Matthew Kalady, MD, of the Cleveland Clinic notes that the findings highlight the need to continually evaluate approaches to colorectal cancer prevention, screening, and treatment. "This manuscript should open the eyes of physicians treating rectal cancer patients and of those making treatment guideline recommendations and screening policies," he wrote. He noted that the study did not address other clinically important endpoints for rectal cancer patients such as local recurrence and disease-free survival. He added that studies are needed to evaluate how factors such as diet, physical activity and obesity, underlying genetics, and gut microbes may interact with rectal cancer biology.

A new type of zebrafish that produces fluorescent tags in migratory embryonic nerve precursor cells could help a Rice University neurobiologist and cancer researcher find the origins of the third-most common pediatric cancer in the U.S.

Rosa Uribe, who was recruited to Rice in 2017 with a CPRIT Scholar grant from the Cancer Prevention and Research Institute of Texas, created the transgenic fish with colleagues at the University of Illinois at Chicago and California Institute of Technology and co-authored a new paper about them this month in the journal Genesis.

The zebrafish line produces fluorescent tags that glow brightly in different colors based on the behavior of a gene called SOX10 that is active in neural crest cells, transient embryonic stem cells that give rise to many cell types in the body, including neurons and cartilage.

"You can see they've already started to migrate that way, and a lot of them are transitioning," Uribe said in her office as she traced the movements of green neural crest cells in a time-lapse movie playing on her computer. In humans, neural crest cells are the point of origin for neuroblastoma, a common pediatric cancer, and Uribe's hoping the new fish can provide clues the disease.

"You can see that a lot of them are transitioning," she said of the cells on her screen. "Some of them are dividing there, there, there. And then they turn off the green, which means they're done dividing."

Why the cells stop dividing is one of the key questions she hopes to answer. SOX10 is one of more than 20 varieties of SOX proteins, and all of them regulate rapid cell division in fast-growing embryos. The same SOX proteins are also often found activated in cancer cells. Finding the "off" switch for SOX10 in neural crest cells could potentially lead to treatments for cancers where SOX proteins play a role, she said.

Uribe earned her bachelor's degree in cell and molecular biology from San Francisco State University and her doctorate from the University of Texas at Austin. She joined Rice following a postdoctoral fellowship at Caltech, where she first began to study the enteric nervous system -- another area of focus for her lab -- which forms from neural crest cells.

"Neural crest cells are stem cells that form from the earliest portion of our central nervous system, the neural tube," said Uribe, assistant professor of biosciences. "They express SOX10 in addition to a bunch of other really important genes."

To view neural crest cells during embryonic development, Uribe's team keeps a stock of breeder fish in a state-of-the-art fish room with hundreds of tanks. Embryos -- for the new reporter line and more than a dozen others -- are removed from the tanks by hand each day and brought to the laboratory for observation.

Zebrafish are used for the studies for several reasons. First, SOX and many other genes in the fish are virtually identical to genes that serve the same basic roles in humans. Second, biologists have amassed a huge body of knowledge about zebrafish, which have been studied as a model organism for decades. Finally, zebrafish breed and develop quickly -- a new batch of embryos can be studied each day in Uribe's lab -- and the fish are transparent, which means researchers can watch what's happening inside them while they are alive.

Using a variety of methods and microscopes, Uribe and her students immobilize live embryos and take photographs to trace their development over a period of hours. For example, the neural crest cells, which first appear in zebrafish embryos about 12 hours after fertilization, were tracked and observed for up to four hours.

"Neural crest cells also do something else that's relevant to cancer," Uribe said. "They undergo something called the epithelial-to-mesenchymal transition, or EMT, shortly after they form, and this is what allows them to break away and migrate to the various places in the embryo."

EMT is important for embryonic development because it allows cells to revert backward along their developmental path and become more stem-like. This malleability allows embryonic cells to form new tissues, but researchers have found many metastatic cancers that use the same genetic circuitry.

Metastasis, or the spread of cancer to other parts of the body, causes more than 90 percent of cancer deaths. EMT is the switch employed by many cancer cells to break away and become metastatic.

Having the ability to observe neural crest cells from the moment they form until they finish migrating is one key to understanding them. Uribe's team will use the new cell line for this, in addition to others that have different colored tags for different reporter genes. They'll also mix and match genes in new strains of zebrafish to test what happens when cells make either too much of a specific protein or too little. Uribe's lab will use a variety of techniques for this, including CRISPR-Cas9.

Microscopes capable of gathering time-lapse images of the variously colored glowing cells are also critical, and Uribe's lab has seven of them. These include a state-of-the-art robotic instrument with tiny hoses and pumps that can draw a single embryo from a numbered test chamber up through a hose, transport it to the microscope focal plane, bring it into focus, rotate it for photos from any angle and then return it and repeat the process for up to 95 more embryos.

"For the migration time-lapse images there is software that's capable of following individual cells for hours," Uribe said. "We can get angles and trajectories, maps of routes taken by one cell or groups of cells, and we can get quantitative data, like velocities and proliferation rates."

Uribe said CPRIT funding was critical for the purchase of lab equipment that she'll be using to trace the origins of neuroblastoma in neural crest cells.

"Our work on neuroblastoma could only happen with the support of CPRIT," she said.

A team of multidisciplinary researchers at the University of Waterloo has identified three basic video game player traits that will help to make game design more personalized and more effectively motivate gamers in both entertainment and work applications.

Gustavo Fortes Tondello, a PhD candidate at Waterloo who co-authored the study with Lennart Nacke, an associate professor and director of the Human-Computer Interaction Games Group at Waterloo's Games Institute, has been developing a more definitive player traits model that gives scores for different preferences. The model generates scores for three different traits, including the degree to which players prefer action elements, aesthetic aspects, or goal orientation in games. Identifying traits makes it possible to analyze player preferences for different groups of people, including different age ranges or genders.

"By better understanding what people like when playing games, we can determine how best to apply those elements to situations that are not games," Tondello said. "We can create systems that are more pleasant to use and help people feel more engaged and motivated to achieve their goals."

The research began by analyzing a dataset of over 50,000 respondents who had been surveyed for an earlier player satisfaction model called BrainHex, developed by Chris Bateman with Nacke and colleague Regan Mandryk.

With BrainHex, researchers identified player archetypes, including seeker, survivor, daredevil, mastermind, conqueror, socializer, and achiever. In contrast, this more recent model generates scores for three different "traits," including the degree to which players prefer action elements, aesthetic aspects, or goal orientation in games. It's possible to then analyze those player preferences for groups of people who are in different age categories, or different genders, for example.

Tondello and Nacke, have been exploring what motivates people and helps keep them playing certain games. Ultimately, they want to use the information to make game design more personalized and more effectively motivate gamers in both entertainment and work applications.

"Some people have been found to really enjoy daredevil, fast action elements of games, while others like the aesthetic elements, such as the art and graphic design," said Nacke. "The story can also be necessary for drawing some people into a game.

"If we can build systems that can adapt to and accommodate individual differences, interactive systems become more exciting and motivating for every one of us."

Designing new molecules for pharmaceuticals is primarily a manual, time-consuming process that's prone to error. But MIT researchers have now taken a step toward fully automating the design process, which could drastically speed things up -- and produce better results.

Drug discovery relies on lead optimization. In this process, chemists select a target ("lead") molecule with known potential to combat a specific disease, then tweak its chemical properties for higher potency and other factors.

Often, chemists use expert knowledge and conduct manual tweaking of molecules, adding and subtracting functional groups -- atoms and bonds responsible for specific chemical reactions -- one by one. Even if they use systems that predict optimal chemical properties, chemists still need to do each modification step themselves. This can take hours for each iteration and may still not produce a valid drug candidate.

Researchers from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) and Department of Electrical Engineering and Computer Science (EECS) have developed a model that better selects lead molecule candidates based on desired properties. It also modifies the molecular structure needed to achieve a higher potency, while ensuring the molecule is still chemically valid.

The model basically takes as input molecular structure data and directly creates molecular graphs -- detailed representations of a molecular structure, with nodes representing atoms and edges representing bonds. It breaks those graphs down into smaller clusters of valid functional groups that it uses as "building blocks" that help it more accurately reconstruct and better modify molecules.

"The motivation behind this was to replace the inefficient human modification process of designing molecules with automated iteration and assure the validity of the molecules we generate," says Wengong Jin, a PhD student in CSAIL and lead author of a paper describing the model that's being presented at the 2018 International Conference on Machine Learning in July.

Joining Jin on the paper are Regina Barzilay, the Delta Electronics Professor at CSAIL and EECS and Tommi S. Jaakkola, the Thomas Siebel Professor of Electrical Engineering and Computer Science in CSAIL, EECS, and at the Institute for Data, Systems, and Society.

The research was conducted as part of the Machine Learning for Pharmaceutical Discovery and Synthesis Consortium between MIT and eight pharmaceutical companies, announced in May. The consortium identified lead optimization as one key challenge in drug discovery.

"Today, it's really a craft, which requires a lot of skilled chemists to succeed, and that's what we want to improve," Barzilay says. "The next step is to take this technology from academia to use on real pharmaceutical design cases, and demonstrate that it can assist human chemists in doing their work, which can be challenging."

"Automating the process also presents new machine-learning challenges," Jaakkola says. "Learning to relate, modify, and generate molecular graphs drives new technical ideas and methods."

Generating molecular graphs

Systems that attempt to automate molecule design have cropped up in recent years, but their problem is validity. Those systems, Jin says, often generate molecules that are invalid under chemical rules, and they fails to produce molecules with optimal properties. This essentially makes full automation of molecule design infeasible.

These systems run on linear notations of molecules, called "simplified molecular-input line-entry systems," or SMILES, where long strings of letters, numbers, and symbols represent individual atoms or bonds that can be interpreted by computer software. As the system modifies a lead molecule, it expands its string representation symbol by symbol -- atom by atom, and bond by bond -- until it generates a final SMILES string with higher potency of a desired property. In the end, the system may produce a final SMILES string that seems valid under SMILES grammar, but is actually invalid.

The researchers solve this issue by building a model that runs directly on molecular graphs, instead of SMILES strings, which can be modified more efficiently and accurately.

Powering the model is a custom variational autoencoder -- a neural network that "encodes" an input molecule into a vector, which is basically a storage space for the molecule's structural data, and then "decodes" that vector to a graph that matches the input molecule.

At encoding phase, the model breaks down each molecular graph into clusters, or "subgraphs," each of which represents a specific building block. Such clusters are automatically constructed by a common machine-learning concept, called tree decomposition, where a complex graph is mapped into a tree structure of clusters -- "which gives a scaffold of the original graph," Jin says.

Both scaffold tree structure and molecular graph structure are encoded into their own vectors, where molecules are group together by similarity. This makes finding and modifying molecules an easier task.

At decoding phase, the model reconstructs the molecular graph in a "coarse-to-fine" manner --gradually increasing resolution of a low-resolution image to create a more refined version. It first generates the tree-structured scaffold, and then assembles the associated clusters (nodes in the tree) together into a coherent molecular graph. This ensures the reconstructed molecular graph is an exact replication of the original structure.

For lead optimization, the model can then modify lead molecules based on a desired property. It does so with aid of a prediction algorithm that scores each molecule with a potency value of that property. In the paper, for instance, the researchers sought molecules with a combination of two properties -- high solubility and synthetic accessibility.

Given a desired property, the model optimizes a lead molecule by using the prediction algorithm to modify its vector -- and, therefore, structure -- by editing the molecule's functional groups to achieve a higher potency score. It repeats this step for multiple iterations, until it finds the highest predicted potency score. Then, the model finally decodes a new molecule from the updated vector, with modified structure, by compiling all the corresponding clusters.

Valid and more potent

The researchers trained their model on 250,000 molecular graphs from the ZINC database, a collection of 3-D molecular structures available for public use. They tested the model on tasks to generate valid molecules, find the best lead molecules, and design novel molecules with increase potencies.

In the first test, the researchers' model generated 100 percent chemically valid molecules from a sample distribution, compared to SMILES models that generated 43 percent valid molecules from the same distribution.

The second test involved two tasks. First, the model searched the entire collection of molecules to find the best lead molecule for the desired properties -- solubility and synthetic accessibility. In that task, the model found a lead molecule with a 30 percent higher potency than traditional systems. The second task involved modifying 800 molecules for higher potency, but are structurally similar to the lead molecule. In doing so, the model created new molecules, closely resembling the lead's structure, averaging a more than 80 percent improvement in potency.

The researchers next aim to test the model on more properties, beyond solubility, which are more therapeutically relevant. That, however, requires more data. "Pharmaceutical companies are more interested in properties that fight against biological targets, but they have less data on those. A challenge is developing a model that can work with a limited amount of training data," Jin says.

NASA's Aqua satellite revealed showed deep convection in Fabio dissipated by the morning of July 6. The system now consists of a swirl of low- to-mid-level clouds.

Despite the lack of strong thunderstorms and deep convection, Fabio is creating ocean swells that are affecting portions of the coasts of southern California and the Baja California Peninsula. These swells are likely to cause life-threatening surf and rip current conditions.

An infrared image taken on July 6 at 7 a.m. EDT (11 UTC) by the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Aqua satellite showed no strong convection remained in Fabio. Coldest temperatures around Fabio's center were near minus 40 degrees Fahrenheit (minus 40 degrees Celsius) and were limited to a very small area.

Strong convection can be found when cloud top temperatures exceed minus 63 degrees Fahrenheit (minus 53 degrees Celsius), and MODIS imagery showed much warmer cloud top temperatures.

At 5 a.m. EDT (0900 UTC), the center of Tropical Storm Fabio was located near latitude 21.5 degrees north and longitude 129.0 degrees west. That's about 1,225 miles (1,970 km) west of the southern tip of Baja California, Mexico. The National Hurricane Center (NHC) said Fabio was moving toward the west-northwest near 14 mph (22 kph).

The cyclone is forecast to continue moving west-northwestward at a slower forward speed for the next couple of days, and then turn toward the west by the end of the weekend.

Maximum sustained winds are near 40 mph (65 kph) with higher gusts. Weakening is forecast and Fabio is expected to degenerate into a remnant low later today.

NHC forecaster Daniel Brown noted "the cyclone will be moving over sea surface temperatures below 20 degrees Celsius (too cold to maintain a tropical cyclone) very soon and into a more stable environment. As a result, organized deep convection is not likely to redevelop and the cyclone is forecast to become a remnant low later today and continue to gradually spin down over the next 2 to 3 days. The global models indicate that the remnant low will degenerate into a trough (elongated area) of low pressure in a little more than 3 days (July 9).

CORVALLIS, Ore. -- New research shows that mice and voles scurry to bear scats to forage for seeds, finding nutritional value in the seeds and in some cases further dispersing them.

The study is published in the journal Ecosphere by researchers at Oregon State University and the Alaska Department of Fish and Game. The research builds on an OSU study that determined that bears are the primary seed dispersers of berry-producing shrubs in Alaska.

In southeastern Alaska, brown and black bears are plentiful because of salmon. Bears frequently supplement their salmon-based diet with fruit as they build their fat stores for winter hibernation. As a result, their seed-filled scats are found throughout the landscape.

"Salmon can have a far greater impact on the ecosystem than we thought," said study lead author Yasaman Shakeri, an Oregon State University graduate now with the Alaska Department of Fish and Game. "Our study shows how small mammals can benefit indirectly from salmon through high bear densities that salmon support and the resulting seed-filled scats on the landscape. Not only are small mammals spending months feeding and fighting for the seeds in scats, they're also scattering the seeds on the landscape, which allows some of the seeds to become future fruiting plants."

The researchers placed motion-triggered cameras near bear scats in the upper Chilkat Valley, 30 miles north of Haines, from June to October in 2014 and 2015. They recorded visits to the scat made by small mammals and birds.

Northwestern deer mice made 4,295 total visits to the scats - an average of 8.5 a day. Northern red-backed voles visited 1,099 times at an average of 2.2 times a day. In addition to the cameras, the researchers also live-trapped and tagged small mammals to estimate their abundance and population densities.

The team collected bear scats on roads and trails within the study area from July-September in 2014 and 2015 and analyzed the nutritional characteristics found in the 12 species of fruit found in the scats, including gross energy, total dietary fiber, crude protein and crude fat. From those samples, they estimated digestible energy per seed.

The energy within the seeds in bear scats can be a significant portion of the energy budget of rodents. For example, a single bear scat contained 73,230 devil's club seeds, which was capable of meeting the daily energy requirements of 91 deer mice. In coastal Alaska riparian areas, bears are potentially capable of indirectly subsidizing the energy needs of 45-65 percent of local deer mouse populations, Shakeri said.

In addition to consuming the seeds at the site, the mice appear to scatter-hoard the seeds in much the same way that gray squirrels scatter-hoard acorns, said Taal Levi, an ecologist in OSU's College of Agricultural Sciences and co-author on the study. Scatter-hoarding is creating a large number of small hoards, as opposed to a large hoard found in a single place.

"This process is called secondary seed dispersal and forgotten seeds can have much higher survival than unburied seeds," Levi said.

The study was also co-authored by Kevin White, a wildlife biologist with the Alaska Department of Fish and Game. The M.J. Murdock Charitable Trust and OSU's Department of Fisheries and Wildlife provided funding for the study.

Shakeri has posted videos on YouTube of deer mice and a vole foraging for berries in bear scat.

Throughout history, humans have deliberately translocated rabbits and hares (leporids) around the world, so they now occupy every continent (except Antarctica). A new Mammal Review article examines studies on the 12 leporid species that have been introduced by humans to areas beyond their native ranges, highlighting the animals' effects on the ecosystem at different levels.

The authors note that leporids can provide food resources to predators, modify nutrient availability and soil structure, compete with native herbivores, consume crops, and have other impacts. Therefore, conservation biologists should carefully consider the contrasting effects of leporids when planning management strategies including these species.

"Although conservation issues and economic costs produced by rabbits' introductions around the world are well known, there is a lack of systematic information about this regarding their closest relatives. Hares and rabbits share some biological traits which could make them successful invaders and profoundly change the invaded regions. Perhaps one of the most notorious effects (among the many that they produce), is that they constitute a new and abundant food resource to a wide variety of predators, ultimately changing biological communities," said co-author Dr. Facundo Barbar, of Universidad Nacional del Comahue, in Argentina. "Considering all introduced leporid species and their many effects on the ecosystems in crucial at the time of planning conservation strategies."

The Baltic Sea is home to some of the world's largest dead zones, areas of oxygen-starved waters where most marine animals can't survive. But while parts of this sea have long suffered from low oxygen levels, a new study by a team in Finland and Germany shows that oxygen loss in coastal areas over the past century is unprecedented in the last 1500 years. The research is published today in the European Geosciences Union journal Biogeosciences.

According to the researchers, human-induced pollution, from fertilisers and sewage running off the countries surrounding the Baltic into the sea, is the main driver of recent oxygen loss in the region's coastal waters. The spread of low-oxygen areas can have dire consequences for the environment and for local populations as it can reduce fish yields and even lead to massive mortality of marine animals.

"The Baltic was strongly impacted by human nutrient inputs in the 20th century and is still experiencing the legacy of those inputs today," says Tom Jilbert, an assistant professor at the University of Helsinki, Finland, who took part in the research. But despite recent measures to reduce the release of polluting nutrients, the researchers write in the new study that they found "no evidence of recovery" from oxygen depletion in the Archipelago Sea, a coastal area between mainland Finland and Sweden that is part of the Baltic.

A reason, they say, may be climate change. Since warm waters are less effective at holding oxygen, "global warming is likely to exacerbate oxygen depletion," says Sami Jokinen, a researcher at the University of Turku, Finland, and lead-author of the Biogeosciences study. Jilbert adds: "Climate change was not the main cause of the current dead zone, but it is an important factor delaying the recovery."

To find out what fuelled oxygen loss in the past and what role climate played, the team drilled and studied a 4-metre-long sediment core from the seafloor in the Archipelago Sea. This allowed them to see, for the first time, how oxygen levels changed in this area over the past 1500 years. This period includes the Medieval Climate Anomaly, a time of warmer climate but low nutrient pollution from 900 to around 1350, as well as modern times.

"The interesting finding from our study is that, in the coastal areas, oxygen loss in the modern period really stands out, due to the strong signal of recent human nutrient inputs," says Jilbert. The team found that oxygen levels were also low during the warmer medieval period, but they write in their study that the present oxygen loss is "unprecedentedly severe," showing how excess pollution and warmer temperatures can combine to make dead zones thrive.

The team also found that this recent oxygen loss started in the early 1900s, decades before it had been previously thought and prior to regular water-quality monitoring. "This is surprising because the 1950s is often regarded as the period of rising oxygen depletion in the Baltic Sea, which has been linked to the substantial increase in human-induced nutrient loading around that time," says Jokinen. Landmass in the Baltic Sea area has been rising since the end of the Ice Age removed weighty ice sheets from the region, and this uplift makes some coastal areas more sensitive to oxygen loss. "On top of this, we found evidence of marked human-induced nutrient loading already at the turn of the 20th century, which likely stimulated oxygen depletion in coastal areas," he continues.

This nutrient loading has long-term effects, making it hard to stop the ongoing spread of dead zones. Rivers in the inhabited coastlines of the Baltic carry nutrients into the sea, triggering algal blooms. As the algae die, they sink to the seafloor and are decomposed by bacteria, which use up oxygen in this process. "If human nutrient inputs are reduced, this might be expected to reduce the blooms and shrink the dead zone," explains Jilbert. But, in dead zones, the decaying algae release phosphorus more efficiently, which then flows back to surface waters where it leads to the growth of cyanobacteria (blue-green bacteria), which, in turn, capture nitrogen from the atmosphere. "As a result, the total amount of nutrients - phosphorus and nitrogen - in the water remains high even after human inputs have been reduced," says Jilbert. "It is a self-sustaining vicious circle that can take decades to reverse," adds Jokinen.

"Nowadays, and likely in the future, oxygen loss in the Archipelago Sea is sustained by the continued leakage of nutrients from the agricultural land, the release of phosphorus from the sediments to the water column due to low oxygen levels, and by the ongoing global warming." says Jokinen. "Hopefully our study will contribute to the better recognition of climate change as a substantial driver of oxygen loss in the Baltic alongside human-induced nutrient loading. To achieve good ecological status in coastal areas under the projected global warming, the required reduction in nutrient input might be higher than previously thought," concludes Jokinen.

"The good news is that many countries in the Baltic catchment have taken significant steps towards nutrient loading reductions," says Jilbert. "In some coastal regions we are already seeing improvements. Better understanding of the balance between nutrient inputs and climate change will therefore help to guide management of the Baltic in the future."

SAN DIEGO, CA - ACL injuries are one of the most common sports injuries affecting adolescent athletes, leading to lost playing time and high healthcare costs. Research presented today at the American Orthopaedic Society for Sports Medicine's Annual Meeting in San Diego shows athletes who experience fatigue - tested on a standardized assessment -¬ demonstrated increased risk of ACL injury. The study is the first to measure the direct impact of fatigue on injury risk in the adolescent population.

"We studied 85 athletes at an average age of 15.4 years, and found 44.7% showed an increased injury risk after high-intensity aerobic activity," noted lead author Mohsin S. Fidai, MD, from Henry Ford Health System in Detroit. "Additionally, 68% of those studied were identified as having a medium- or high-risk for injury following the activity, as compared to 44% at baseline."

The study utilized vertical and drop-jump assessments of each athlete, which were captured on video and reviewed by 11 professional health observers. Participants included track and field, basketball, volleyball, and soccer athletes. Injury risk was also associated with the level of fatigue, as 14 of 22 athletes demonstrating over 20% fatigue showed an increased ACL injury risk. Female athletes and those over age 15 were also more likely to demonstrate an increased injury risk.

"While ACL injury prevention programs are commonly used now, a decrease in injury numbers has not followed suit," commented Fidai. "We hope this study helps advocate for ACL injury prevention training programs to incorporate fatigue resistance training and awareness by coaches, trainers and physical education teachers."

Rockville, Md. (July 5, 2018)--A drug used in stem cell therapy to treat certain cancers may also protect against cigarette smoke-induced lung injury. The study, published ahead of print in the American Journal of Physiology--Lung Cellular and Molecular Physiology, was chosen as an APSselect article for July.

Plerixafor is a medication that stimulates the immune system to release more of a type of stem cell (hematopoietic progenitor cells, or HPCs) from the bone marrow into the bloodstream. The drug is used to treat some types of cancer that originate in the blood cells, including multiple myeloma and non-Hodgkin lymphoma. Stem cells have the potential to develop into many different kinds of cells in the body and are involved in tissue repair. Previous research has shown that lower numbers of HPCs in the bloodstream correspond to increased severity of emphysema, a form of chronic obstructive pulmonary disease (COPD). COPD is a progressive lung disease that makes breathing difficult.

Studies suggest the reduced number of circulating HPCs prevents the lungs from being able to repair smoke-related damage. Based on this theory, researchers explored the effect of plerixafor on stem cell circulation--and subsequent lung function--in mice. One group of animals was exposed to cigarette smoke five days a week for 22 weeks and received regular injections of plerixafor ("treated"), and another group was exposed to smoke but did not receive treatment ("exposed").

The researchers collected stem cells from all groups of mice and found a drop in the number of cells in the exposed group early in the trial period, which is consistent with findings that even brief cigarette smoke exposures reduce HPC populations in the bone marrow, according to the research team. Conversely, there was no detectable depletion of HPCs in the treated group, and, in fact, numbers increased after two weeks of treatment. Lung fluid samples from the treated group showed no significant changes in the number of white blood cells or inflammation as compared to a control group. Increases in these factors typically indicate illness or injury.

The protective effects of plerixafor on smoke-induced lung injury "raise the possibility that [bone marrow] mobilization increases the availability of HPC for lung cell maintenance and repair," the researchers wrote. "Our report supports the usefulness of this FDA-approved drug as a potential treatment for emphysema."

Electronic radio tags could be used to track invasive Asian hornets and stop them colonising the UK and killing honeybees, new research shows.

Scientists from the University of Exeter attached tiny tags to Asian hornets, then used a tracking device to follow them to their nests; the first time this has been achieved.

They tested the technique in southern France and Jersey - where Asian hornets are well established - and the tags led researchers to five previously undiscovered nests.

"Our new method of tracking offers a really important new tool to tackle the spread of this invader, providing an efficient means of finding hornets' nests in urban, rural and wooded environments," said lead researcher Dr Peter Kennedy, of the Environment and Sustainability Institute on the University of Exeter's Penryn Campus in Cornwall.

Asian hornets prey on honeybees and other pollinators, and the scientists say the technique demonstrated in their study could help protect Britain's "beleaguered pollinator populations".

"It is vital to find the nests early in the season to prevent the hornet spreading, as later in the year hundreds of new queens emerge and disperse from each nest, each with the potential to make new nests," said Professor Juliet Osborne, a co-author on the study, and Director of the Environment and Sustainability Institute.

The work was funded as part of Defra's efforts to prepare for future outbreaks of the Asian hornet in the UK.

South West beekeepers also saw the urgency of the work, supporting it with their own funds.

Nicola Spence, Defra Deputy Director for Plant and Bee Health, said: "This work is key for ensuring a rapid response to Asian hornets when sightings are confirmed, and in future bee inspectors will be able to use this technique to take swift action."

"In France, the Asian hornet is unlikely to be eliminated, so efforts are now focussed more on limiting their impact," said Dr Denis Thiéry from INRA Bordeaux-Aquitaine in France, who collaborated on this work.

Mr Willie Peggie, Director of The States of Jersey Department of the Environment, where the technique was also tested, said: "We are pleased to be investigating efficient methods of tracking Asian hornets to their nests, as we're concerned about their impact on our wild insect pollinators, as well as their effect on local honey production."

The researchers used the smallest radio tags available - made by UK firm Biotrack Ltd - and attached them to hornets with sewing thread. Hornets were able to carry them as long as the tag weighed less than 80% of the insect's weight.

Asian hornets are the latest threat to Britain's honeybees, which - like many pollinators - are suffering due to factors including habitat loss, parasites and pesticides.

The British Beekeepers Association are also pleased about the development of a reliable technique for tracking this invasive predator, and stated: "The BBKA are greatly concerned about the possible incursion by the Asian Hornet because of the devastation likely to be caused to honeybees and other pollination insects."

Adult Asian hornets "hawk" at beehives, meaning that they hover outside to grab bees, before dismembering them and taking them back to their nest to feed to larvae.

The first Asian hornet discovered in Britain was in Gloucestershire in 2016, when a nest was found and destroyed. Another nest was destroyed in Woolacombe, Devon, last year. In April this year, a single hornet was found in Lancashire.

Asian hornets are smaller than native European hornets, have a largely dark brown or black body and yellow-tipped legs, a distinctive orange-yellow stripe near the end of their abdomen, and often a thin orange-yellow line just behind the "waist". Their face is orange, and the back of the head is black, unlike the European hornet in which both the face and back of the head are yellow.

Any suspected sighting of an Asian hornet should be reported, ideally with a photo, via email to alertnonnative@ceh.ac.uk or by using the Asian Hornet Watch app.

The paper, published in the journal Communications Biology, is entitled: "Searching for nests of the invasive Asian hornet (Vespa velutina) using radio-telemetry."