Culture

Earth's climate was relatively stable for a long period of time. For three billion years, temperatures were mostly warm and carbon dioxide levels high - until a shift occurred about 400 million years ago. A new study suggests that the change at this time was accompanied by a fundamental alteration to the carbon-silicon cycle. "This transformation of what was a consistent status quo in the Precambrian era into the more unstable climate we see today was likely due to the emergence and spread of new life forms," said Professor Philip Pogge von Strandmann, a geoscientist at Johannes Gutenberg University Mainz (JGU). Together with researchers from Yale University, notably Boriana Kalderon-Asael and Professor Noah Planavsky, he has traced the long-term evolution of the carbon-silicon cycle with the help of lithium isotopes in marine sediments. This cycle is regarded as a key mechanism controlling the Earth's climate, as it regulates carbon dioxide levels and, with it, temperature. The researchers' findings have been published recently in Nature.

The carbon-silicon cycle is the key regulator of climate

The carbon-silicon cycle has kept Earth's climate stable over long periods of time, despite extensive variations in solar luminosity, in atmospheric oxygen concentrations, and the makeup of the Earth's crust. Such a stable climate created the conditions for long-term colonization of the Earth by life and allowed initially simple and later complex life forms to develop over billions of years. The carbon-silicon cycle contributes to this by regulating the level of carbon dioxide in the atmosphere. Silicate rock is transformed into carbonate rock as a result of weathering and sedimentation, and carbonate rock is transformed back into silicate rock by, among other things, volcanism. When silicate rock is converted to carbonate rock, carbon dioxide is removed from the atmosphere, while the reverse process releases carbon dioxide once again. "We consider this to be the main mechanism by which Earth's climate is stabilized over the long term," explained Pogge von Strandmann.

To trace long-term carbon-silicon cycles back in time and gain a better understanding of the precise relationships governing Earth's climate, the research team studied the ratio of lithium isotopes in marine carbonates. Lithium is present only in silicate rocks and their silicate and carbonate weathering products. The research team analyzed more than 600 samples deposited as sediments in shallow primeval marine waters and obtained from more than 100 different rock strata from around the world, including from Canada, Africa and China. "We used these samples to create a new database covering the past three billion years," Pogge von Strandmann pointed out.

These data show that the ratio of lithium-7 to lithium-6 isotopes in the oceans was low from three billion years ago to 400 million years ago, and then suddenly increased. It was precisely at this time that land plants evolved, while simultaneously marine animals with skeletons composed of silicon, such as sponges and radiolarians, spread throughout the oceans. "Both played a role, but as yet we do not know exactly how the processes are coupled," Professor Philip Pogge von Strandmann added.

The displacement of 'clay factories' to the land influences the carbon-silicon cycle

Research findings suggest that there was a massive change to the extent of the formation of clay, a secondary silicate rock composed of very fine particles, in the Earth's past - possibly due to an increase in clay formation on land and a decrease in the oceans. Clay formation is a crucial component of the carbon-silicon cycle and it influences the ratio of lithium isotopes. On land it is caused by the extensive weathering of silicate rocks, but in the oceans a range of different processes is involved. Increased continental clay formation is thought to have lowered carbon dioxide levels in the atmosphere. In contrast, oceanic clay formation, known as "reverse weathering", releases CO2, so its decline will similarly have lowered atmospheric carbon dioxide levels.

According to the authors of the Nature paper, this suggests that the mode of climate regulation on Earth as well as the primary location where that process occurs has changed dramatically through time: "The shift from a Precambrian Earth state to the modern state can probably be attributed to major biological innovations - the radiation of sponges, radiolarians, diatoms and land plants." The result of this modification of climate regulation has been apparent ever since in the form of the frequent alternation between cold glacial periods on the one hand and warmer periods on the other. However, this climate instability, in turn, helps to accelerate evolution.

Burnout. It is a syndrome that is said to afflict humans who feel chronic stress. But after conducting a novel study using trail cameras showing the interactions between white-tailed deer fawns and predators, a Penn State researcher suggests that prey animals feel it, too.

"And you can understand why they do," said Asia Murphy, who recently graduated with a doctorate from Penn State's Intercollege Graduate Degree Program in Ecology. "Less than half of whitetail fawns live to see their first birthday, and many are killed by predators, such as coyotes, black bears and bobcats. Fawns instinctively 'know' they are in constant danger."

Ironically, the presence of humans -- who mean the fawns no harm and likely would protect them if they could -- only ratchets up the stress the young animals experience, Murphy added. Even if it's just people hiking on a trail in a state park, it is a disturbance to be avoided by fawns, leaving less landscape and less time for them to feed and evade predators.

"The presence of people creates an environment where the danger seems so high that the animals basically stop having vigilance behaviors," she said. "That was the surprising thing about my research -- when fawns perceive that there is so much danger coming from so many sources, their behavior seemed like they just relaxed, like there's no point in being ready to hide or flee. I saw that in older deer, too."

In areas where there are many predators and people present, fawns seem to relax instead of acting hypervigilant, she noted.

"Like so much constant stress leaves them burned out," she said.

The goal of the study was to examine how human-dominated landscapes influence the timing, frequency and physical spacing and locations of interactions between humans, black bears, coyotes, bobcats and fawns, as well as to contrast deer vigilance behavior at each location. The researchers compared "camera trap" data from six surveys in and around three central Pennsylvania public forest sites with different surroundings -- forest, agriculture and development.

The Bald Eagle and Rothrock State Forest sites were surrounded by agriculture and low-density housing, whereas the Susquehannock State Forest site was surrounded by largely unbroken forest. Analyzing more than 10,000 photos, researchers observed markedly different behavior of fawns, adult deer and predators at the three locations, dictated, they suggest, by the presence of humans and their changes to the landscape.

Camera trap surveys began in mid- to late-May, which coincided with the start of the period when fawns are born and are most vulnerable to predation, and ended in mid-September, before the hunting season. Researchers randomly established 18 camera locations at each of the three study sites, spaced a minimum of a half mile apart within an area of about 100 square miles.

At least one camera was placed at each location and typically remained there for an average of 47 days before being moved to a new location. Cameras were set to take three pictures when triggered by an animal with a one-minute rest period. Each location was baited with a combination of bobcat urine, a skunk-based scent attractant and a fatty acid tablet.

In findings recently published in the Journal of Animal Ecology, the researchers reported that bears, bobcats, coyotes, fawns and adult deer all had more frequent timing overlaps in the agriculture and development sites compared to the mostly unbroken forest site. In addition, factors that influenced deer vigilance, such as distance to forest edge and predator abundance in the agriculture and development sites, were not factors in the mostly unbroken forest site.

"By taking into account the different antipredator behaviors that can be detected and the different scales at which these behaviors might occur, we were able to gain a more comprehensive picture of how humans reduce available niche space for wildlife," Murphy said. "It was clear that disturbed landscapes -- agriculture and development -- create more time and space overlap between predators and fawns."

This research is important because it is among the first to document that human land disturbance influences the dynamics of predator-prey interactions, according to Murphy's adviser, Duane Diefenbach, adjunct professor of wildlife ecology in the College of Agricultural Sciences. Wildlife biologists suspected human interference enhances opportunities for predators, but they had not seen proof.

"This study shows that antipredator behavior by fawns varies across space, time and predator species," said Diefenbach, who is leader of the U.S. Geological Survey's Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State. "When multiple predator species co-occur but vary in their use of space, time of activity and hunting mode, it creates a complex landscape for prey trying to avoid predation. Human presence has the potential to shift interactions among predators and prey and where and when encounters occur."

Reducing greenhouse gas emissions (GHGs) and nitrogen water pollution from agriculture are top environmental priorities in the United States. Key to achieving climate goals is helping producers navigate carbon markets, while also helping the environment and improving farm income.

A new tool developed by a University of Minnesota research team allows farmers to create a budget balance sheet of any nitrogen reduction plans and see the economic and environmental cost, return and margins, all customized to fields under their management.

“With these numbers in mind, farmers can make more informed decisions on nitrogen mitigation that not only saves them money, but also significantly reduces pollutants to the environment,” said Zhenong Jin, who led the research and is an assistant professor in the Department of Bioproducts and Biosystems Engineering (BBE) in the College of Food, Agricultural and Natural Resource Sciences (CFANS).

Previous tools did not allow for customized predictions for every field in the U.S. corn belt, as the computational and storage costs of running these crop models at large scale would be very expensive.

As outlined in an article published in IOPscience, the research team built a series of machine-learning-based metamodels that can almost perfectly mimic a well-tested crop model at much faster speeds. Using the metamodels, they generated millions of scenario simulations and investigated two fundamental sustainability questions — where are the mitigation hotspots, and how much mitigation can be expected under different management scenarios.

“We synthesized four simulated indicators of agroecosystem sustainability — yield, N2O emissions, nitrogen leaching, and changes in soil organic carbon — into economic net societal benefits as the basis for identifying hotspots and infeasible land for mitigation,” said Taegon Kim, CFANS research associate in the BBE department. The societal benefits include cost savings from GHG mitigation, as well as improved water and air quality.

“By providing key sustainability indicators related to upstream crop production, our metamodels can be a useful tool for food companies to quantify the emissions in their supply chain and distinguish mitigation options for setting sustainability goals,” said Timothy Smith, professor of Sustainable Systems Management and International Business Management in CFANS’s BBE department.

The study, conducted in the U.S. Midwest corn belt, found that:

Reducing nitrogen fertilizer by 10% leads to 9.8% less N2O emissions and 9.6% less nitrogen leaching, at the cost of 4.9% more soil organic carbon depletion, but only a 0.6% yield reduction over the study region.
The estimated net total annual social benefits are worth $395 million (uncertainty ranges from $114 million to nearly $1.3 billion), including a savings of $334 million by avoiding GHG emissions and water pollution, $100 million using less fertilizer, and a negative $40 million due to yield losses.
More than 50% of the net social benefits come from 20% of the study areas, thus can be viewed as hot spots where actions should be prioritized.

“Our analysis revealed hot spots where excessive nitrogen fertilizer can be cut without yield penalty,” said Jin. “We noticed in some places that reducing nitrogen-related pollution comes at a cost of depleting organic carbon in soil, suggesting that other regenerative practices, such as cover cropping, need to be bundled with nitrogen management.”

In the future, the team will expand the framework presented in this study and develop more advanced and accurate carbon qualification models through a combination of process-based models, artificial intelligence and remote sensing.

CHAMPAIGN, Ill. -- A new study shows that it is possible to use mechanical force to deliberately alter chemical reactions and increase chemical selectivity - a grand challenge of the field.

The study led by University of Illinois Urbana-Champaign researcher Jeffrey Moore and Stanford University chemist Todd Martinezz demonstrates how external mechanical forces alter atomic motions to manipulate reaction outcomes. The study findings are published in the journal Science.

"We think of chemical reactions as molecules moving on a surface of potential energy in the way hikers follow the contour map of mountains and valleys along a trail," said lead author Yun Liu, a post-doctoral researcher in Moore's research group. "A mountain along a reaction path is a barrier that needs to be traversed before the molecules can descend into their final product. Therefore, the relative height of barriers control which path the molecules will most likely choose, allowing chemists to make predictions about what a particular chemical reaction will produce - an outcome called selectivity."

Chemists have traditionally assumed that the jiggling of molecules - known as "molecular dynamics" - is governed by a potential energy surface. Molecules transform by chemical reactions that seek the path requiring a minimum amount of energy. However, emerging evidence shows that molecules often do not have time to sample the surface, leading to deviations called nonstatistical dynamic effects, the researchers said.

Nonstatistical dynamic effects are observed in some common reactions such as nitration of benzene and dehydration reactions," Liu said. "Despite these examples, NDEs have not fully captured chemists' attention because they are difficult to measure and cannot be controlled to change the reaction outcomes - the essential pursuit of chemistry."

Liu developed an experimental design using a carbon-13 isotope-labeled ring molecule with two polymer chains attached. Liu placed the polymers into a reaction vessel and applied a mechanical force via sonication, which rips the ring into two separate groups.

"The ring molecule can convert to one of three different products after being ripped apart, making it a good model for investigating NDEs," Liu said. "The 13-C label allows us to track and measure the chemical changes occurring to the ring, making it distinct from thousands of other chemical bonds in the polymer."

Liu hypothesizes that with the excitation of mechanical force, the atoms heat up along specific reaction directions, rather than following the directions shaped by the potential energy surface. The researchers named this departure from the conventional concept of chemical reactions a "flyby trajectory."

"Using the hiking example, the hypothesis is equivalent to saying that the hiker just decided not to follow the map," Liu said. "Instead, the hiker was excited enough to hop onto a hang-glider and just fly by between hills on their descent. As a result, the direction in which the molecules move becomes dependent on their initial jump, rather than the subsequent barrier height."

Liu performed multiple experiments demonstrating the tunability of the flyby trajectory by increasing the mechanical force so that the reaction can increasingly overcome barriers. Ideally, researchers can turn an unselective reaction into a highly selective one where any side products formed are undetectable.

To support the experimental finding, Stanford University graduate student Soren Holm collected 10,000,000 computed geometries to construct a theoretical model of the potential energy surface and then extracted the speed of reaction trajectories under the presence of mechanical force.

"We found that early trajectories do not slow down when moving past the barriers," Liu said.

In other words, barriers are flown past rather than being surmounted, which should have slowed down the chemical reaction rate, the researchers said. Over time, the molecules cool down, and subsequent trajectories follow the minimum energy path initially predicted.

"Our findings will give researchers a more complete understanding of how force can alter the course of chemical reactions to increase production efficiency," Moore said. "It's another tool in our toolbox to make the things we use every day."

The National Science Foundation, the Army Research Office, the Dr. Leni Schoninger Foundation and the Deutsche Forschungsgemeinschaft supported this research.

Moore is the director of the Beckman Institute for Advanced Science and Technology, a professor of chemistry and materials sciences and engineering and is affiliated with the Center for Advanced Study, the Materials Research Laboratory, the Carle Illinois College of Medicine, the Carl R. Woese Institute for Genomic Biology and the Center for Social and Behavioral Science.

A new national study published in Public Health Nutrition on July 15 found that Americans experiencing food insufficiency were three times as likely to lack mental health support during the COVID-19 pandemic than those not experiencing food insufficiency.

The most extreme form of food insecurity, food insufficiency occurs when families do not have enough eat. Among a nationally representative sample of 68,611 adults who participated in the US Census Household Pulse Survey in October 2020, 11% reported food insufficiency. Of those, 24% also reported an unmet mental health need compared to 9% of food-sufficient adults.

"Hunger, exhaustion, and stress related to not getting enough food to eat may lead to depression and anxiety," says lead author, Jason Nagata, MD, assistant professor of pediatrics at the University of California, San Francisco.

"The experience of food insecurity could lead affected people to prioritize food over other needs such as seeking health care, using up considerable time and energy to navigate food pantries and free meal services, or locate and visit affordable food stores."

Food insufficiency was also associated with higher use of psychiatric medications: 27% of food-insufficient adults reported psychiatric medication use compared to 19% of food-sufficient adults.

"To better address these problems, medical professionals, social workers, and clinicians can screen patients for both symptoms of anxiety and depression to ensure they have sufficient access to food," says co-author Kyle T. Ganson, PhD, assistant professor at the University of Toronto's Factor-Inwentash Faculty of Social Work.

The researchers argue that clinicians should assess for food insecurity and provide referrals to food assistance programs.

"Policymakers should focus on increasing funding for food assistance and mental health services as part of pandemic relief legislation," says Nagata. "Expanding access to supplemental food programs may help to mitigate the need for more mental health services during the pandemic."

A national study published in the Journal of Pediatrics found that Emergency Department (ED) visits by youth for self-harm were nearly 40 percent higher in rural areas compared to urban settings. Strikingly, ED visits by youth for self-inflicted firearm injuries were three times more common in rural areas. Youth from rural areas presenting to the ED for suicidal ideation or self-harm also were more likely to need to be transferred to another hospital for care, which underscores the insufficient mental health resources in rural hospitals.

"Our study used pre-pandemic data, and we know that increased attention to youth mental health is even more pressing now everywhere, but especially in rural settings to prevent self-harm in youth," said lead author Jennifer Hoffmann, MD, pediatric emergency medicine physician at Ann & Robert H. Lurie Children's Hospital of Chicago and Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine. "We need universal screening for suicidal ideation for all children and adolescents age 10 and up who present in the ED to identify youth at risk and intervene before tragedy occurs."

The study used national data on suicidal ideation or self-harm in youth (ages 5-19 years) from a sample of EDs across the country, including those in general hospitals and children's hospitals. Dr. Hoffmann and colleagues extrapolated the results to reach national estimates.

Dr. Hoffmann explains that a number of factors contribute to higher suicide rates and self-harm in rural youth. Access to mental healthcare is a huge challenge, she says. Shortages of pediatric mental health professionals in rural areas play a significant role, requiring patients to travel long distances for help, which is a barrier for many. Also, lower family income and higher unemployment rates in rural areas may result in poor insurance coverage, especially for mental health. In small towns, there are also concerns with anonymity, which may cause delays in seeking care until a crisis brings the child to the ED. Rural families are also more likely to own firearms, so increased access to firearms may account for the high degree of disparity in self-inflicted firearm injuries.

"We need to improve mental health training for ED providers, allocate more resources and implement policies in rural hospitals on managing young patients who present with suicidal ideation or self-harm," said Dr. Hoffmann. "More widespread use of tele-psychiatry also might help prevent unnecessary transfers to other hospitals. But even more importantly, we need to train primary care providers to help diagnose and treat mental health issues earlier, so we can prevent self-inflicted injuries and death."

Add this to the list of real-life spidey senses: Harvard researchers have shown that jumping spiders are able to tell the difference between animate objects and inanimate objects -- an ability previously known only in vertebrates, including humans.

Using a specialized treadmill system and a point-light display animation, the team of scientists found that these spiders are able to recognize biological motion. This type of motion refers to the visual movements that come from living organisms when they are moving. The visual cue is how people, even babies, can tell someone is another person just by the way their bodies move. Many animals can do this, too.

The ability, which is critical for survival, is evolutionarily ancient since it is so widespread across vertebrates. The study from the Harvard team is believed to be the first demonstration of biological motion recognition in an invertebrate. The findings pose crucial questions about the evolutionary history of the ability and complex visual processing in non-vertebrates.

"[It] opens the possibility that such mechanisms might be widespread across the animal kingdom and not necessarily related to sociality," the researchers wrote in the paper, which published in PLOS Biology on Thursday.

The study was authored by a team of researchers working in the lab of Paul Shamble, a John Harvard Distinguished Science Fellow. Massimo De Agrò (previously a postdoctoral researcher in the lab and now at the Animal Comparative Economics laboratory at the University of Regensburg, Germany) lead the project, along with co-authors Daniela C. Rößler (now a Zukunftskolleg Postdoctoral Fellow at the University of Konstanz and the Max Planck Institute of Animal Behavior), and Kris Kim (a researcher in the Shamble Lab).

The researchers chose jumping spiders to test biological motion cues because the animals are among the most visually adept of all arthropods. With eight eyes, for example, vision plays a central role in a wide range of behaviors.

They placed the jumping spiders, a species called Menemerus semilimbatus, into a forced choice experiment. They suspended the spiders above a spherical treadmill so their legs could make contact with it. The spiders were kept in a fixed position so only its legs could move, transferring its intended direction to the sphere which spun freely because of a constant stream of compressed air shooting up below it.

(Friendly disclaimer: No spiders were harmed during the experiment and all were freed in the same place they were captured afterwards.)

Once in position, the spiders were presented two animations as stimuli. The animations were called point-light displays, each consisting of a dozen or so small lights (or points) that were attached to key joints of another spider so they could record its movements. The body itself is not visible, but the digital points give a body-plan outline and impression of a living organism. In humans, for example, it only takes about eleven dots on the main joints of the body for observers to correctly identify it as another person.

For the spiders, the displays followed the motion of another spider walking. Most of the displays gave the impression of seeing a living animal. Some of the displays were less real than others and one, called a random display, did not give the impression it was living.

The researchers then observed how the spiders reacted and which light display they turned toward on the treadmill. They found the spiders reacted to the different point-light displays by pivoting and facing them directly, which indicated that the spiders were able to recognize biological motion.

Curiously, the team found the spiders preferred rotating towards the more artificial displays and always toward the random one when it was part of the choice. They initially thought they would turn more toward the displays simulating another spider and possible danger, but the behavior made sense in the context of jumping spiders and how their secondary set of eyes work to decode information.

"The secondary eyes are looking at this point-light display of biological motion and it can already understand it, whereas the other random motion is weird and they don't understand what's there," De Agrò said.

The researchers hope to look into biological motion recognition in other invertebrates such as other insects or mollusks. The findings could lead to greater understanding of how these creatures perceive the world, De Agrò said.

LA JOLLA, CALIF. - July 16, 2021 - An international research group, led by Jamey Marth, Ph.D., a professor at Sanford Burnham Prebys, has shown that the Neuraminidase 3 (Neu3) enzyme is responsible for the onset and progression of colitis--a chronic digestive disease caused by inflammation of the colon. The study, recently published in the Proceedings of the National Academy of Sciences, was performed in a model of recurrent human food poisoning previously linked with the condition. The findings represent a scientific advance toward a targeted therapy to help the millions of people worldwide affected by the disorder.

"Our new research demonstrates how increased activity of Neu3--an enzyme found in the gut--triggers an inflammatory cascade that leads to disease," says Marth. "Prior to this study, we knew that a neuraminidase enzyme was involved, but didn't know the source of the enzyme.

"This study pinpoints Neu3 as the protein that triggers onset and progression of colitis," adds Marth. "In the absence of Neu3, disease onset and progression do not occur, indicating that the enzyme may be a valuable therapeutic target."

Previously, the Marth laboratory developed a unique model of colitis based on recurrent human food poisoning, which can identify environmental sources of disease. The (mouse) model reflects how humans may contract colitis following repeated, mild infections of Salmonella enterica Typhimurium (ST), a common human food poisoning pathogen.

"We're now looking at an intrinsic mechanism of protein aging and turnover that's being modified by a foodborne pathogen," says Marth. "The pathogen targets the protein aging process in the intestinal tract, thereby diminishing the expression of a key anti-inflammatory enzyme that would normally prevent the onset of colitis and inflammatory bowel diseases (IBDs).

"That enzyme is intestinal alkaline phosphatase (IAP), which detoxifies bacterial toxins, and its augmentation is also the rationale for current clinical trials in the treatment of colitis and sepsis.

"The problem starts when the ST pathogen is ingested and triggers our immune system to 'amp up' Neu3 neuraminidase expression," adds Marth. "Increased activity of Neu3 leads to a reduced life span of IAP, and that impairs the ability to detoxify a damaging endotoxin normally found among bacteria in the gut--and this leads to chronic gut inflammation."

Inhibiting Neu3 with the antiviral drug Relenza (used to treat influenza) broke that chain, reduced inflammatory cytokine expression and prevented severe colitis. However, current neuraminidase inhibitors such as Relenza and Tamiflu are optimized for viral and bacterial neuraminidases and would need further development to be clinically effective against the human form of Neu3.

"We had to increase the oral dose of Relenza well above that recommended for use in humans," says Marth. "It worked without apparent side effects; however, a new generation of neuraminidase inhibitors that target the mammalian enzyme is needed. Several research groups are now focusing on developing clinically relevant inhibitors.

"We were rather surprised that the culprit turned out to be Neu3, as many bacteria in the gut are capable of synthesizing their own neuraminidase enzymes," Marth notes. "Based on the genetic proof in our study, inhibiting Neu3 would be expected to have a positive therapeutic impact. But there's also another option: augmenting IAP appears to be equally beneficial. Perhaps a dual approach including both oral Neu3 inhibition and oral IAP augmentation simultaneously could be even more effective at reducing inflammation and preventing the onset of colitis."

PHILADELPHIA - People who struggle with serious mental illnesses are more likely to die early - about 10 to 30 years early - than those without mental illness from any cause. Many factors contribute to this disparity including poor access to care, undetected health conditions and difficulty managing chronic health conditions. Addressing physical illness in those with serious mental illness has been a major challenge. To address this, researchers tested a peer-led intervention called the Bridge that helps patients with mental illness prioritize their health, access health care and develop skills to self-manage their health. The approach showed a 50% reduction in emergency room use for those in the intervention group.

"Many people de-prioritize their health when faced with other crises, or more immediate issues," says Erin Kelly, PhD, assistant professor in the department of Family and Community Medicine at Thomas Jefferson University.
"There are many barriers to regular medical care for people with mental illness. We developed and evaluated one intervention aimed at relieving some of those barriers."

The study was published in the journal Psychiatric Services.

The researchers evaluated the impact of the Bridge program, a six-month intervention led by trained peers --those who had lived experiences with mental illness. The peer facilitators guide participants through a three-phase process, which they call the "for them, with them, by them."

In the first phase, the peer health navigator helped participants to set health and wellness goals, showed participants how to make appointments for routine or specialty care, and coached them through stressful aspects of the process in one-on-one sessions. In the second phase, participants gradually take over and self-manage all aspects of their health and health care, until they are independently able to manage as much as they can on their own (the third phase). Peers who deliver the interventions are certified peer specialists who first complete a four-day training course on the Bridge intervention as well as 8-12 weeks of supervised coaching. Supervisors are also trained in a one-day session to ensure that they understand how to evaluate performance and support the intervention.

In this study, Dr. Kelly, together with collaborators from University of Southern California, University of California, Los Angeles, and Pacific Clinics examined whether the Bridge intervention changed how participants made use of health services in a large health system in Southern California between March 2014 and September 2015.

Looking at Medicaid data of the 144 of 151 participants analyzed in the study (primarily Latinx and Black participants), the researchers found participants in the Bridge program used the emergency room 2.5 times less often than those in a waitlist control group over six months. "This is important because we often see high rates of emergency department visits in patients with severe mental illnesses," says Dr. Kelly.

Participants also reported using routine health care more frequently, and reported more confidence in their ability to manage their health, better relationships with primary care providers, reduced pain and increased detection of chronic health conditions.

"People with severe mental illnesses encounter multiple challenges accessing health care," say Dr. Kelly, "Therapists often have little training on how to handle chronic disease, and physicians often have little training in terms of treating patients with severe mental illnesses. Our intervention provides a trustworthy bridge between the two."

This program is not yet available in the Philadelphia area but could be an important addition to health care post-COVID-19, as many people have avoided routine care and may be missing important screenings or have deprioritized their health due to other stressors.

People with learning disabilities with covid-19 are five times more likely to be admitted to hospital and eight times more likely to die compared with the general population of England, finds a study published by The BMJ today.

Risks were particularly high for those with severe to profound learning disability, Down's syndrome and cerebral palsy.

The researchers say prompt access to covid-19 testing and healthcare is warranted for this group, and prioritisation for covid-19 vaccination and other targeted preventive measures should be considered.

Emerging evidence has shown that people with learning disability are at higher risk from covid-19 related death compared with the general population. But results from existing studies on other covid-19 outcomes are often complicated by factors such as deprivation and underlying conditions (comorbidities).

A lack of clarity also exists on the increased risk of covid-19 deaths among people with milder learning disability.

To explore this further, a team of UK researchers set out to describe the risk of covid-19 related hospital admissions and deaths among children and adults with learning disability in England compared with the general population.

Their results are based on electronic health records for more than 17 million people registered with a general practice in England linked to hospital admission and mortality data.

Data for 14,312,023 adults and 2,627,018 children were analysed across both waves of the covid-19 pandemic: wave 1 (registered with a general practice as of 1 March 2020 and followed until 31 August 2020); and wave 2 (registered 1 September 2020 and followed until 8 February 2021).

Among 90,307 adults on the learning disability register, 538 (0.6%) had a covid-19 related hospital admission; there were 222 (0.25%) covid-19 related deaths and 602 (0.7%) non-covid deaths.

Among adults not on the register, 29,781 (0.2%) had a covid-19 related hospital admission; there were 13,737 (0.1%) covid-19 related deaths and 69,837 (0.5%) non-covid deaths.

After taking account of potentially influential factors, such as age, sex, ethnicity, and geographical location, adults on the learning disability register had a 5-fold higher risk of covid-19 related hospital admission and an 8-fold higher risk of covid-19 related death than adults not on the register.

Rates were higher among those with severe to profound learning disability than those with milder learning disability, and among those in residential care.

Similar patterns were seen for children, but the authors stress that absolute risks of covid-19 hospital admission and death among children were small.

These are observational findings and the authors point to some limitations, such as focusing only on severe covid-19 outcomes and being unable to identify everyone with a learning disability from medical records alone. Nevertheless, results were similar after further analyses, and are consistent with the existing literature, suggesting that they are robust.

The findings also highlight gaps in learning disability registers, limiting the reach of the vaccination programme, prompting a call for greater efforts to update and maintain accurate registers so that all eligible individuals can benefit.

Besides vaccination, efforts should continue to protect people with learning disability from covid-19 adverse outcomes, and more research on the excess covid-19 risks among people with Down's syndrome and cerebral palsy are needed, they conclude.

This study makes an important contribution to the evidence on how the pandemic has affected this vulnerable group, say researchers in a linked editorial.

Ken Courtenay at the Royal College of Psychiatrists and Vivien Cooper at the Challenging Behaviour Foundation, point to "a hidden calamity" taking place among people with learning disabilities, and say "reasonable adjustments should be made to ensure that information about the pandemic and risk of infection are accessible, and that practical support is provided to protect people and manage risks."

What's more, they say worrying attitudes and prejudices about the value of the lives of people with learning disabilities have surfaced during the pandemic, while the covid-19 vaccination programme also disadvantaged people with learning disabilities, prioritising people according to age rather than severity of comorbid disorders.

"Before the next pandemic, investment in research is essential, to help us understand the risks faced by people with learning disabilities and how best to protect them from the high risks of hospital admission and death from covid-19," they write. "People with learning disabilities have the same rights as everyone else, including the right to good health and to be safe from harm."

BOSTON - Over the last decade, investigators at Beth Israel Deaconess Medical Center (BIDMC) have been at the forefront of the effort to identify the small population of neurons deep within the brain that cause hunger, but precisely how these cells and the unpleasant feeling of hunger they cause actually drive an animal to find and eat food remained unclear.

Now, a study published in the journal Nature sheds new light on this long-standing question. Led by Bradford B. Lowell, MD, PhD, of the Division of Endocrinology at BIDMC, the study makes use of a genetically engineered mouse model developed at BIDMC to reveal the complex interplay among the neurons that govern hunger, behavior and learning.

"Our discovery provides the answer to this important question of how we learn to seek and consume food and how hunger enhances the learning of tasks oriented towards acquiring food," said Lowell, who is also a professor of medicine at Harvard Medical School. "With additional work, our discovery could ultimately shed light into what goes wrong in disorders of hunger such as obesity and anorexia nervosa."

Focusing on the AgRP hunger neurons -- the small sub population of neurons found in the brain's hypothalamus responsible for creating the sensation of hunger after periods of deprivation -- Lowell and colleagues used the BIDMC-developed mouse model to investigate the neurons' activity. The mouse model -- on which more than 100 scientific papers have been published -- allows researchers to switch AgRP neurons on and off, determine what activates or inactivates them, and map their connections to other regions of the brain.

"Using this model, we and others discovered some time ago that these neurons are turned on by fasting, causing hunger, and that artificially turning them on in a recently fed mouse that otherwise would not eat, causes huge amounts of food to be eaten, as if the mouse had not eaten in days," said first author Janet Berrios, PhD, postdoctoral fellow at BIDMC.

Moreover, just the presence of food or a cue linked to the presence of food will instantaneously inhibit the neuron's activity, easing the unpleasant hunger sensation. If food isn't eaten in a short period of time, however, neuronal activity rebounds, restoring hunger to its previous levels.

In the present study, the team trained the engineered mice to recognize a food cue by associating a light with access to food, just as a dog can be trained to associate the sound of a cupboard opening with getting a biscuit. Thanks to the genetically engineered mice, the scientists observed how various levels of hunger and the presence of the food cues affected the AgRP neurons.

As they expected, they observed that fasting activated AgRP neurons, and food cues in the environment -- via a network of neurons elsewhere in the brain -- work to inhibit AgRP activity. But remarkably, when the team blocked off this network, it caused the mice to have great difficulty learning a task in which sensory cues related to food were used to guide acquisition of food.

From this, the researchers suggest that fasting or deprivation -- known to activate the AgRP neurons and the feeling of hunger -- causes an unpleasant, or aversive, feeling. When food cues in the environment inhibit AgRP activity, it also tamps down the aversive feeling, which in turn serves as a reward powerful enough to enhance learning.

"It's as if these rewarding, sensory cue-linked drops in unpleasant AgRP neuron activity push the mouse towards environmental cues and tasks associated with obtaining food," said Lowell, who noted that thirst likely works the same way, although through a different specialized set of neurons. "An obvious implication of this idea is that it explains why dieting is so difficult -- dieters are perpetually stuck with this aversive feeling. So, in short, it appears that we eat and drink because we've learned that this reduces the activity of these deprivation neurons, and hence the linked bad feelings."

Highlights

The physician-scientist workforce doing kidney research in the United States is increasingly made up of women and international medical graduates.

However, this workforce is older, declining in relative number, and is less overwhelmingly focused on basic rather than clinical science.

Washington, DC (July 14, 2021) -- U.S. physician-scientists make enormous contributions to biomedical research. New research published in CJASN demonstrates increasing representation of women and international graduates within the physician-scientist workforce doing kidney research; however, this workforce is declining in relative number, is getting older, and is less overwhelmingly focused on basic science research.

The research relied on public data obtained from the internet. A team led by Susan M. Wall, MD (Emory University School of Medicine) mined records from the National Institutes of Health (NIH) to explore demographic changes of early career and established, physician and non-physician principal investigators doing kidney-focused NIH-funded research between 1990 and 2020.

The researchers found that kidney-focused principal investigators are aging, particularly among physicians. Moreover, the relative representation of physicians among both early career and established principal investigators is falling, particularly among those doing basic science research. In contrast, the number and relative representation of non-physician scientists is increasing. There is also greater representation of women and international graduates among physician and non-physician kidney-focused investigators; however, women physician-scientists are increasingly more likely to do clinical rather than basic science research.

"Physician-scientists are in a unique position to formulate testable hypotheses that are clinically relevant. Research training also provides a perspective that is useful when evaluating human disease in the clinic," said Dr. Wall.

What The Study Did: In this randomized clinical trial, a physician messaging campaign was effective in increasing COVID-19 knowledge, information-seeking and self-reported protective behaviors among diverse groups.

Authors: Esther Duflo, Ph.D., of the Massachusetts Institute of Technology in Cambridge, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2021.17115)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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Media advisory: The full study and commentary are linked to this news release.

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time http://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2021.17115?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=071421

About JAMA Network Open: JAMA Network Open is the new online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.

What The Study Did: About half the women experiencing homelessness and unstable housing who were surveyed experienced symptoms of depression or anxiety or both during the pandemic and, in addition to unmet subsistence needs and social isolation, these symptoms were associated with increased challenges accessing non-COVID-19 care and managing symptoms for chronic medical conditions.

Authors: Elise D. Riley, Ph.D., M.P.H., of the University of California, San Francisco, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2021.17035)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #
Media advisory: The full study is linked to this news release.

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time http://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2021.17035?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=071421

About JAMA Network Open: JAMA Network Open is the new online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.

What The Study Did: This study found an unequal pattern of COVID-19 outcomes that was associated with the socioeconomic circumstances in regions of Japan, suggesting that these disparities in COVID-19 outcomes aren't unique to the United States and Europe.

Authors: Yuki Yoshikawa, M.D., M.P.H., of the Harvard T.H.Chan School of Public Health in Boston, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2021.17060)

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

#  #  #
Media advisory: The full study is linked to this news release.

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time http://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2021.17060?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=071421

About JAMA Network Open: JAMA Network Open is the new online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.