Culture

Scientists at the University of Southampton have conducted a study that highlights the importance of studying a full range of organisms when measuring the impact of environmental change - from tiny bacteria, to mighty whales.

Researchers at the University's School of Ocean and Earth Science, working with colleagues at the universities of Bangor, Sydney and Johannesburg and the UK's National Oceanography Centre, undertook a survey of marine animals, protists (single cellular organisms) and bacteria along the coastline of South Africa.

Lead researcher and postgraduate student at the University of Southampton, Luke Holman explains: "Typically, biodiversity and biogeography studies focus on one group of species at a time, often animals. Studying animals, protist and bacteria together - organisms vastly different in size, separated by billions of years of evolution - gave us the opportunity to take a broader view of the marine ecosystem. We discovered remarkably consistent biogeographic groupings for the three across the coastline - consistent with previously studied patterns, driven by regional currents."

Findings are published in the journal Nature Ecology and Evolution.

The team took seawater samples in numerous locations along the length of the South African coast, from the warmer seas of the east, to the cooler waters of the west and the intermediate temperatures in the south. The samples were filtered, had environmental DNA extracted and underwent sophisticated lab analysis to indicate the diverse range of organisms found in particular locations.

Results showed a broad range of animals living in the sea along the whole length of coast, but with differences in the exact species in warm, cold and intermediate regions. This same pattern of difference was also shown in bacteria and protists - demonstrating consistency in the biodiversity of life for each region.

Furthermore, the scientists found that among the variables examined temperature had the greatest impact on determining the diversity of animals and bacteria, whereas protists were associated more with chlorophyll concentration in the water. The team also revealed that while all three groups were affected to some extent by human activity, such as shipping, fishing and building of marinas, this wasn't to the extent they'd expected.

Commenting on the study, Luke said: "We hope our work encourages researchers to consider other groups of organisms, both in biogeographic assessments and marine protection and restoration projects. For example, a project aiming to restore a coral reef might also need to consider the bacterial communities, or the protection of a river system might also ensure the protists communities are monitored in addition to the fish."

Moving forwards the team hope to learn more about the causes and consequences of global marine biodiversity change for all life, from microscopic bacteria and protists to macroscopic organisms like fish and marine mammals.

The dynamics of the neural activity of a mouse brain behave in a peculiar, unexpected way that can be theoretically modeled without any fine tuning, suggests a new paper by physicists at Emory University. Physical Review Letters published the research, which adds to the evidence that theoretical physics frameworks may aid in the understanding of large-scale brain activity.

"Our theoretical model agrees with previous experimental work on the brains of mice to a few percent accuracy -- a degree which is highly unusual for living systems," says Ilya Nemenman, Emory professor of physics and biology and senior author of the paper.

The first author is Mia Morrell, who did the research for her honors thesis as an Emory senior majoring in physics. She graduated from Emory last year and is now in a post-baccalaureate physics program at Los Alamos National Laboratory in New Mexico.

"One of the wonderful things about our model is that it's simple," says Morrell, who will start a Ph.D. program in physics at New York University in the fall. "A brain is really complex. So to distill neural activity to a simple model and find that the model can make predictions that so closely match experimental data is exciting."

The new model may have applications for studying and predicting a range of dynamical systems that have many components and have varying inputs over time, from the neural activity of a brain to the trading activity of a stock market.

Co-author of the paper is Audrey Sederberg, a former post-doctoral fellow in Nemenman's group, who is now on the faculty at the University of Minnesota.

The work is based on a physics concept known as critical phenomena, used to explain phase transitions in physical systems, such as water changing from liquid to a gas.

In liquid form, water molecules are strongly correlated to one another. In a solid, they are locked into a predictable pattern of identical crystals. In a gas phase, however, every molecule is moving about on its own.

"At what is known as a critical point for a liquid, you cannot distinguish whether the material is liquid or vapor," Nemenman explains. "The material is neither perfectly ordered nor disordered. It's neither totally predictable nor totally unpredictable. A system at this 'just right' Goldilocks spot is said to be 'critical.'"

Very high temperature and pressure generate this critical point for water. And the structure of critical points is the same in many seemingly unrelated systems. For example, water transitioning into a gas and a magnet losing its magnetism as it is heated up are described by the same critical point, so the properties of these two transitions are similar.

In order to actually observe a material at a critical point to study its structure, physicists must tightly control experiments, adjusting the parameters to within an extraordinarily precise range, a process known as fine-tuning.

In recent decades, some scientists began thinking about the human brain as a critical system. Experiments suggest that brain activity lies in a Goldilocks spot -- right at a critical transition point between perfect order and disorder.

"The neurons of the brain don't function just as one big unit, like an army marching together, but they are also not behaving like a crowd of people running in all different directions," Nemenman says. "The hypothesis is that, as you increase the effective distance between neurons, the correlations between their activity are going to fall, but they will not fall to zero. The entire brain is coupled, acting like a big, interdependent machine, even while individual neurons vary in their activity."

Researchers began searching for actual signals of critical phenomena within brains. They explored a key question: What fine tunes the brain to reach criticality?

In 2019, a team at Princeton University recorded neurons in the brain of a mouse as it was running in a virtual maze. They applied theoretical physics tools developed for non-living systems to the neural activity data from the mouse brain. Their results suggested that the neural activity exhibits critical correlations, allowing predictions about how different parts of the brain will correlate with one another over time and over effective distances within the brain.

For the current paper, the Emory researchers wanted to test whether fine-tuning of particular parameters were necessary for the observation of criticality in the mouse brain experiments, or whether the critical correlations in the brain could be achieved simply through the process of it receiving external stimuli. The idea came from previous work that Nemenman's group collaborated on, explaining how biological systems can exhibit Zipf's law -- a unique pattern of activity found in disparate systems.

"We previously created a model that showed Zipf's law in a biological system, and that model did not require fine tuning," Nemenman says. "Zipf's law is a particular form of criticality. For this paper, we wanted to make that model a bit more complicated, to see if could predict the specific critical correlations observed in the mouse experiments."

The model's key ingredient is a set of a few hidden variables that modulate how likely individual neurons are to be active.

Morrell wrote the computer code to run simulations and test the model on her home desktop computer. "The biggest challenge was to write the code in a way that would allow it to run fast even when simulating a large system with limited computer memory without a huge server," she says.

The model was able to closely reproduce the experimental results in the simulations. The model does not require the careful tuning of parameters, generating activity that is apparently critical by any measure over a wide range of parameter choices.

"Our findings suggest that, if you do not view a brain as existing on its own, but you view it as a system receiving stimuli from the external world, then you can have critical behavior with no need for fine tuning," Nemenman says. "It raises the question of whether something similar could apply to non-living physical systems. It makes us re-think the very notion of criticality, which is a fundamental concept in physics."

The computer code for the model is now available online, so that anyone with a laptop computer can access it and run the code to simulate a dynamic system with varying inputs over time.

"The model we developed may apply beyond neuroscience, to any system in which widespread coupling to hidden variables is extant," Nemenman says. "Data from many biological or social systems are likely to appear critical via the same mechanism, without fine-tuning."

Scientists at the Institute for Cooperative Upcycling of Plastics (iCOUP), an Energy Frontier Research Center led by Ames Laboratory, have discovered a chemical process that provides biodegradable, valuable chemicals, which are used as surfactants and detergents in a range of applications, from discarded plastics. The process has the potential to create more sustainable and economically favorable lifecycles for plastics.

The researchers targeted their work on the deconstruction of polyolefins, which represents more than half of all discarded plastics, and includes nearly every kind of product imaginable-- toys, food packaging, pipe systems, water bottles, fabrics, shoes, cars, and furniture.

"Plastics, and especially polyolefins, are materials you could call too successful," said iCOUP Director Aaron Sadow. "They are fantastic-- strong, lightweight, thermally stable, chemically resistant-- for all the applications that we use them for, but the problem comes when we don't need them anymore."

It's all in the chemical construction of polyolefin plastics that makes them so tough and durable-- long strong chains of carbon-carbon bonds-- that also makes them hard to break down. Polyolefins also generally lack the chemical groups which could be targeted in deconstruction processes. Many existing processes to recycle plastic result in less-valuable, less usable components, making the economic feasibility of recycling far less appealing.

The new process uses what science already knows about key steps of polymerization-- the assembling of long polymer strands-- but in reverse, by breaking some of the carbon-carbon bonds in the chains. Once a few carbon-carbon bonds are broken, the shortened polymer chains transfer to an aluminum end group to form reactive species. The catalysts and reactions for this new process are related to those used in alkene polymerization, leveraging well-understood catalytic chemistry. Finally, the intermediates of this new transformation are easily converted into fatty alcohols or fatty acids, or used in other synthetic chemistry, to create chemicals or materials that are valuable in a whole host of ways: as detergents, emulsifiers, pharmaceuticals, and cosmetics. Because the process is catalytically controlled, desirable product chain lengths can be targeted for synthesis.

The best part about the process is that its end products are biodegradable, unlike polyethylene and polypropylene starting materials.

"Fatty acids and alcohols biodegrade in the environment relatively quickly. If these byproducts go on to find a new use elsewhere, that's wonderful, but it also has an end of life, which means it won't accumulate in the environment as plastics have," said Sadow.

There is consistent, strong evidence that the SARS-CoV-2 virus, which causes COVID-19, is predominantly transmitted through the air, according to a new assessment published today in the medical journal Lancet. Therefore, public health measures that fail to treat the virus as predominantly airborne leave people unprotected and allow the virus to spread, according to six experts from the UK, USA and Canada, including Jose-Luis Jimenez, chemist at the Cooperative Institute for Research in Environmental Sciences (CIRES) and University of Colorado Boulder.

"The evidence supporting airborne transmission is overwhelming, and evidence supporting large droplet transmission is almost non-existent," Jimenez said. "It is urgent that the World Health Organization and other public health agencies adapt their description of transmission to the scientific evidence so that the focus of mitigation is put on reducing airborne transmission."

The team of experts, led by the University of Oxford's Trish Greenhalgh, reviewed published research and identified 10 lines of evidence to support the predominance of the airborne route.

At the top of their list: Super-spreader events such as the Skagit Choir outbreak, in which 53 people became infected from a single infected case. Studies have confirmed these events cannot be adequately explained by close contact or touching shared surfaces or objects.

Moreover, transmission rates of SARS-CoV-2 are much higher indoors than outdoors, and transmission is greatly reduced by indoor ventilation.

The team highlighted research estimating that silent (asymptomatic or presymptomatic) transmission of SARS-CoV-2 from people who are not coughing or sneezing accounts for at least 40 percent of all transmission. This silent transmission is a key way COVID-19 has spread around the world, "supporting a predominantly airborne mode of transmission," according to the assessment. The researchers also cited work demonstrating long-range transmission of the virus between people in adjacent rooms in hotels; people who were never in each other's presence.

By contrast, the team found little to no evidence that the virus spreads easily via large droplets, which fall quickly through the air and contaminate surfaces.

"We were able to identify and interpret highly complex and specialist papers on the dynamics of fluid flows and the isolation of live virus," lead author Greenhalgh said. "While some individual papers were assessed as weak, overall the evidence base for airborne transmission is extensive and robust. There should be no further delay in implementing measures around the world to protect against such transmission."

The new work has serious implications for public health measures designed to mitigate the pandemic. First, "droplet measures" such as handwashing and surface cleaning, while not unimportant, should be given less emphasis than airborne measures, which deal with inhalation of infectious particles suspended in the air.

If an infectious virus is primarily airborne, someone can potentially be infected when they inhale aerosols produced when an infected person exhales, speaks, shouts, sings, or sneezes. So airborne control measures include ventilation, air filtration, reducing crowding and the amount of time people spend indoors, wearing masks whenever indoors (even if not within 6 feet or 2 meters of others), attention to mask quality and fit, and higher-grade PPE for healthcare and other staff when working in contact with potentially infectious people.

"It is quite surprising that anyone is still questioning whether airborne transmission is the predominant transmission pathway for this virus or not," said co-author Professor Kimberly Prather, an aerosol scientist from the University of California San Diego. "Only by including inhalation of aerosols at both close and long range can we explain the many indoor outbreaks that have occurred around the globe. Once we acknowledge this virus is airborne, we know how to fix it. There are many examples of places that have fared much better by acknowledging this virus is airborne from the start. The world needs to follow their lead as soon as possible."

More from the authors

Professor David Fisman, a physician-epidemiologist at the University of Toronto: "It's critically important for public health experts to work collaboratively with aerosol scientists and engineers. Establishment of aerosol transmission as the dominant mode of transmission of SARS-2 is actually good news, because we have abundant expertise for reducing the risk from aerosols. But these tools won't be put into use as long as there is a lack of clarity from public health agencies on how this disease spreads."

Infectious diseases physician Professor Robert Schooley from the University of California San Diego: "When one starts with the understanding that the virus replicates in the lungs and is exhaled with each breath in a range of particle sizes, some of which can travel well beyond the magical 6-foot curtain posited as the limit for droplets--and can persist in poorly ventilated locations--it is inevitable to conclude that public health strategies must center on those that reduce airborne spread of respiratory pathogens."

Professor Zeynep Tufekci, a sociologist from University of North Carolina, Chapel Hill said: "it's essential that the guidelines to the public explain accurately explain transmission mechanisms and their relative importance rather than focusing on binary rules like "six feet" that do not apply the same way across different contexts. Even after a whole year, we still see the widespread practice of unnecessary levels of cleaning to the detriment of public health, use of plexiglass indoors that is far from sufficiently protective and, depending on air flows, may even be contraindicated, instead of attention to ventilation and aerosol risks. We cannot fix this situation without accurately informing the public so that people feel empowered to make decisions to better protect themselves across different contexts, and adjusting guidelines globally to fit the best available evidence."

From cancer treatment to sunlight, radiation and toxins can severely damage DNA in both harmful and healthy cells. While the body has evolved to efficiently treat and restore damaged cells, the mechanisms that allow this natural repair remain misunderstood.

In a new study, Northwestern University researchers have used cryogenic electron microscopy (cryo-EM) to visualize this process by illuminating the mysterious cycle of DNA breakage sensing and repair. The researchers believe this new information could potentially form the basis for understanding how cells respond to chemotherapy and radiation and potentially even lead to improved cancer treatments.

Published Wednesday, April 14 in the journal Nature, the research offers new insight into how proteins work in concert to identify and resolve DNA double-strand breaks (DSB).

When a double strand break, or DSB -- the most severe form of DNA damage -- occurs, the repair pathway may insert or delete genes at the break site or potentially rearrange genes throughout the strand. In cases where chromosomal rearrangement occurs, catastrophic changes can lead to the development of cancer.

Using cryo-EM, researchers can obtain 3D images of macromolecular structures at atomic resolution. According to Yuan He, an assistant of molecular bioscience in the Weinberg College of Arts and Sciences, cryo-EM's ability to image dynamic machinery "goes way beyond the capabilities" of other structural biology techniques.

Imaging DNA-protein complexes at various transitory phases allowed He's team to identify and create a model of a cell's repair pathway.

"There are many factors that work in concert to seal the nick," said He, the study's corresponding author. "We're taking the most straightforward way to solve the problem -- by looking at proteins as they identify and repair a break."

The resulting model shows that, at times, two copies of DSB recognition complexes can hold together and bridge DSBs as the complexes signal for other factors to come to the breaking site. In another essential state, proteins align the two strands of DNA for a ligase to come and seal the nick. The lab then proposed a model of this pathway, showing how DNA bridges and aligns as it transfers between states.

[VIDEO] As the bottom component of the DNA-protein structure comes under stress, DNA strands are bridged to close proximity; once the component returns to a more relaxed state, the movement then joins the two DNA strands together.

"Seeing is believing" is a common saying in molecular biology, and one He thinks applies to his research directly. By observing the elegant process directly, an observer can easily make connections and understand how the complex system works together. But before this technology was available, He said it was akin to a blind person identifying an elephant by touch.

"Breakthroughs are usually thought of for something big and complex," said Siyu Chen, a postdoctoral student in He's lab and first author on the paper. "The question we're answering is fundamental and straightforward: DNA has been broken apart -- so how do proteins join them together?"

The lab hopes findings have implications for how our cells come back from and respond to radiation and chemotherapy. Future research could bring more targeted therapies for this newly understood pathway.

Infection with parasitic intestinal worms (helminths) can apparently cause sexually transmitted viral in-fections to be much more severe elsewhere in the body. This is shown by a study led by the Universities of Cape Town and Bonn. According to the study, helminth-infected mice developed significantly more severe symptoms after infection with a genital herpes viruses (Herpes Simplex Virus). The researchers suspect that these results can also be transferred to humans. The results have now appeared in the journal Cell Host & Microbe.

In sub-Saharan Africa, both worm infections and sexually transmitted viral diseases are extremely com-mon. These viral infections are also often particularly severe. It is possible that these findings are related. At least, this is the conclusion suggested by the current findings from mice.

The scientists involved in the study investigated how an infestation with helminths affects the course of a herpes infection of the female genital tract in the animals. "The results themselves surprised us in their clarity," explains Prof. William Horsnell PhD., of the Institute of Infectious Diseases and Molecular Medi-cine at the University of Cape Town. "Genital herpes disease is often accompanied by scarring of the vagi-na, known as necrosis. In our study, this serious symptomatology occurred twice as often as normal after helminth infestation."

The finding is also surprising because the worms themselves never infest the female genital tract. They are parasites that are ingested with food or through the skin and eventually migrate to the intestines. "So this is a remote effect of helminth infection that was not known before," explains Dr. Laura Layland of the Insti-tute of Medical Microbiology, Immunology and Parasitology at Bonn University Hospital.

Misdirected immune response

The researchers were able to show that a specific group of immune cells, the eosinophil granulocytes, is responsible for the necrotization. These are white blood cells that are specialized in fighting worms and other parasites. They are armed with cell-decomposing enzymes that they carry around inside them. However, these are not freely available - they are too dangerous for that. Instead, they are packed in so-called granules (hence the name "granulocytes"). Upon contact with a parasite, the cells channel these granules to the outside, where they release their deadly cargo.

"In our case, however, the worm infestation in the intestine causes eosinophilic granulocytes to accumu-late in the vagina during a concurrent genital herpes infection," Horsnell points out. "They then secrete their cell-damaging enzymes there, even though no helminths are present. And it's this misdirected im-mune response that leads to the serious damage in the mucosa of the vagina that we've observed."

A specific immune messenger, interleukin-33, appears to play an important role in this process, indirectly causing the accelerated maturation of granulocytes in the vagina. "We inhibited IL-33 with a specific com-pound," Horsnell explains. "The mice then developed significantly less tissue damage in the genital tract." The scientists are now looking for potential drugs that are also suitable for use in humans and that can be produced inexpensively.

Successful cooperation program

The fact that the study could be carried out successfully is also thanks to a cooperation program between Germany and Africa funded by the German Research Foundation (DFG). "The Institute of Medical Micro-biology, Immunology and Parasitology at the University of Bonn sees its role in this as being, among other things, the transfer of know-how," explains Dr. Laura Layland. "We train researchers in the countries on site, for example, in the use of analytical techniques and scientific methods, an offer that also benefits young scientists in particular."

To this end, Layland and her colleagues are conducting workshops in African countries and in Bonn, among other places. The aim is to strengthen existing scientific expertise in the affected regions and thus significantly improve research into and control of parasitic worm infections in the medium term.

A new analysis of antibody and B cell responses in 44 people who received either the Pfizer or Moderna mRNA SARS-CoV-2 mRNA vaccines shows that only one dose may be needed for previously infected patients who have since recovered. The study also supported that two doses is optimal to induce strong antibody and B cell responses in patients who are immunologically naïve for SARS-CoV-2, and antibodies induced by the vaccination could protect against the more infectious and deadly South African variant. The results build on an increasing body of research suggesting that people previously infected with SARS-CoV-2 may only require one dose of mRNA vaccination for optimal immune responses, including new correlations with SARS-CoV-2-specific B cell responses in these patients. Rishi Goel and colleagues studied the antibody and B cell responses in the blood of 33 SARS-CoV-2-naïve patients and 11 patients previously infected with the virus at multiple time points before, during, and after vaccination. Consistent with previous findings, they confirmed that the mRNA vaccines induced antibodies that could neutralize the D614C and B.1.351 variants. These responses peaked one week after the second vaccine dose in naïve patients but peaked two weeks after the first dose in recovered patients, with similar patterns in B cell responses for both groups. Older patients had lower antibody and B cell responses after the second dose, and the generation of new antibody responses relied on SARS-CoV-2-specific B cells in all ages. Thus, Goel et al. confirm previous findings on antibody responses to SARS-CoV-2 mRNA vaccination, while expanding on the importance of B cell responses.

A new study from North Carolina State University found that, on average, voters and local leaders showed greater concern about plastic and other garbage in the ocean after watching kids' presentations.

The findings, published in the journal Frontiers in Political Science, built on previous research that found educating kids about climate change was linked to an increase in concern in parents. The new findings indicate kids can have a broader impact outside of their families.

"Our lab has already established that kids can have an impact across the dinner table, and it's cool to see that they can also have an impact within town halls, too," said the study's lead author Jenna Hartley, a Ph.D. student in the NC State Department of Parks, Recreation and Tourism Management. "We also saw that kids could help close partisan gaps in how community members view this issue."

In the study, researchers surveyed adults after watching educational events or videos developed by approximately 2,500 fourth- and fifth-graders in North Carolina. The students first completed lessons developed by the Duke University Marine Lab Community Science Initiative on how plastics and other trash can end up in waterways.

Then, the students either made in-person presentations or public service announcement (PSA) videos that could be shared virtually with voters and local political leaders.

During the 2018-19 school year, students held eight in-person events including two school plays, an art show, and presentations at a restaurant and school board meeting. Due to the COVID-19 pandemic, all but one of the in-person presentations during the 2019-20 school year were canceled, and students developed PSAs that could be sent online instead.

Researchers received surveys from 172 adults, including 65 voters and 107 local officials, who either attended an in-person event or received a PSA online. The surveys asked the adults to rate their level of concern, on a scale of 1 through 5, about marine debris before and after the presentations, with 1 being extremely unconcerned, and 5 being extremely concerned. They also asked the adults to rate their level of support for policy initiatives on marine debris before and after the presentation on a scale of 1 to 5.

Adults' concern about marine debris increased from an average score of 3.93 to a 4.42. Adults also reported greater support for marine debris policies, with their average score among all participants increasing from a 3.92 to 4.40.

Voters had larger gains in concern about marine debris compared to local officials. Researchers did not find differences in concern or support for policy changes among adults depending on their gender or race, if adults knew the kids or not, or whether the presentations were in-person or virtual.

"Together with some of our other work on kids influencing adults, this study is pointing to a real potential for kids to have a powerful seat at the table," said Kathryn Stevenson, assistant professor of parks, recreation and tourism management at NC State. "Kids can play a real and needed part in the political process, especially if we're making decisions about their futures. We need to consider their perspectives."

The researchers also found kids' presentations could help narrow political divides. Conservatives had a lower average level of concern about marine debris initially at a score of 3.69, while liberals had a higher average at 4.36. Both groups increased their concern on average, with levels of concern among conservatives approaching that of liberals, after the presentations. Conservatives' average score after the presentations was a 4.33, and liberals averaged a score of 4.64.

They found that in terms of support for policy change to prevent or clean up trash in the ocean, liberals and conservatives' average scores remained relatively polarized.

"We have a lot to learn about how powerful this effect is, how long these effects last, how big a difference it can make, and with whom," Stevenson said. "But so far, it's really encouraging. Kids should take heart in that, and know they have power. And educators and parents should understand that kids have an important voice in the community."

A pair of orbiting black holes millions of times the Sun's mass perform a hypnotic pas de deux in a new NASA visualization. The movie traces how the black holes distort and redirect light emanating from the maelstrom of hot gas - called an accretion disk - that surrounds each one.

Viewed from near the orbital plane, each accretion disk takes on a characteristic double-humped look. But as one passes in front of the other, the gravity of the foreground black hole transforms its partner into a rapidly changing sequence of arcs. These distortions play out as light from both disks navigates the tangled fabric of space and time near the black holes.

"We're seeing two supermassive black holes, a larger one with 200 million solar masses and a smaller companion weighing half as much," said Jeremy Schnittman, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who created the visualization. "These are the kinds of black hole binary systems where we think both members could maintain accretion disks lasting millions of years."

The accretion disks have different colors, red and blue, to make it easier to track the light sources, but the choice also reflects reality. Hotter gas gives off light closer to the blue end of the spectrum, and material orbiting smaller black holes experiences stronger gravitational effects that produce higher temperatures. For these masses, both accretion disks would actually emit most of their light in the UV, with the blue disk reaching a slightly higher temperature.

Visualizations like this help scientists picture the fascinating consequences of extreme gravity's funhouse mirror. The new video doubles down on an earlier one Schnittman produced showing a solitary black hole from various angles.

Seen nearly edgewise, the accretion disks look noticeably brighter on one side. Gravitational distortion alters the paths of light coming from different parts of the disks, producing the warped image. The rapid motion of gas near the black hole modifies the disk's luminosity through a phenomenon called Doppler boosting - an effect of Einstein's relativity theory that brightens the side rotating toward the viewer and dims the side spinning away.

The visualization also shows a more subtle phenomenon called relativistic aberration. The black holes appear smaller as they approach the viewer and larger when moving away.

These effects disappear when viewing the system from above, but new features emerge. Both black holes produce small images of their partners that circle around them each orbit. Looking closer, it's clear that these images are actually edge-on views. To produce them, light from the black holes must be redirected by 90 degrees, which means we're observing the black holes from two different perspectives - face on and edge on - at the same time.

"A striking aspect of this new visualization is the self-similar nature of the images produced by gravitational lensing," Schnittman explained. "Zooming into each black hole reveals multiple, increasingly distorted images of its partner."

Schnittman created the visualization by computing the path taken by light rays from the accretion disks as they made their way through the warped space-time around the black holes. On a modern desktop computer, the calculations needed to make the movie frames would have taken about a decade. So Schnittman teamed up with Goddard data scientist Brian P. Powell to use the Discover supercomputer at the NASA Center for Climate Simulation. Using just 2% of Discover's 129,000 processors, these computations took about a day.

Astronomers expect that, in the not-too-distant future, they'll be able to detect gravitational waves - ripples in space-time - produced when two supermassive black holes in a system much like the one Schnittman depicted spiral together and merge.

Banner: In this frame from the new visualization, a supermassive black hole weighing 200 million solar masses lies in the foreground. Its gravity distorts light from the accretion disk of a smaller companion black hole almost directly behind it, creating this surreal view. Different colors for the accretion disks make it easier to track the contributions of each one. Credit: NASA's Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell

New research from the Florida State University College of Medicine has found that the personality trait neuroticism is consistently associated with a higher risk of developing the brain disorder Parkinson's disease.

The research by Professor of Geriatrics Antonio Terracciano and team, published in Movement Disorders, found that adults in the study who scored in the top quartile of neuroticism had more than 80% greater risk of Parkinson's, compared to those who scored lower on neuroticism.

"Some clinicians think that the anxiety and depression is just the result of Parkinson's," Terracciano said. "However, our findings suggest that some emotional vulnerability is present early in life, years before the development of Parkinson's disease."

The effects were similar for women and men and across socioeconomic strata. Furthermore, the association was virtually unchanged in models that excluded incident cases within the first five years of follow-up and remained significant in models that accounted for demographic variables and other risk factors, including smoking, physical activity, anxiety and depression.

Three similar studies have published results consistent with Terracciano's findings, but with smaller sample sizes. Collectively, they provide a "pretty robust and replicable" assessment of the link between neuroticism and Parkinson's, Terracciano said.

"It kind of gives you a better understanding of the risk factors for the disease and what could be a contributing cause," he said. "This is one of many [factors], but the evidence is convincing."

Globally, an estimated six million people suffer from Parkinson's disease -- about 1% of all older adults -- making it the second most common neurodegenerative disease after Alzheimer's. The causes of Parkinson's disease are not well understood, but scientists believe genetic and environmental factors contribute to its onset.

Neuroticism is a personality trait that measures individual differences in the tendency to experience negative emotions, vulnerability to stress, inability to resist urges and self-consciousness. It is one of the five major personality traits known as the "Big Five" or five-factor model of personality and is one of the most studied psychological dispositions for its relevance spanning normal to abnormal emotional functioning.

Neuroticism has been linked to mood disorders and Alzheimer's, but there have been fewer studies on its prospective connection with Parkinson's.

"Individuals who score high in neuroticism are at higher risk for poor health outcomes across the lifespan, particularly in the domain of mental health and neurodegenerative diseases, including Alzheimer's disease and related dementias," Terracciano said.

Central to Terracciano's research was a large-scale study by the UK Biobank, which recruited nearly a half-million individuals ages 40-69 between 2006 and 2010, and collected data obtained over nearly 12 years of follow up. A baseline assessment measured neuroticism. There were 1,142 identified cases of Parkinson's ascertained through UK National Health Service electronic health records or death records up to 2018.

"Anxiety and depression are comorbid with Parkinson's disease," Terracciano said. "Many people with Parkinson's tend to be anxious or tend to get depressed. Part of that could be due to the disease and how it alters the brain and can have an influence on emotions. Part could be a psychological reaction of having a diagnosis of the disease."

Parkinson's is a long-term degenerative brain disorder that causes progressive decline of motor and physical functions. As the disease progresses, nerve cell damage in the brain causes dopamine levels to drop, leading to symptoms such as tremors, slow movement, stiffness and loss of balance. Dopamine is known as a "feel-good" hormone involved in reward, motivation, memory and attention in addition to regulating body movements.

Terracciano led the research team, which included Damaris Aschwanden, a post-doctoral researcher in the FSU Department of Geriatrics, and Angelina Sutin, professor in the FSU Department of Behavioral Sciences and Social Medicine. Researchers from the University of Montpellier in France; the National Research Council, Sant'Anna Institute and Tor Vergata University of Rome in Italy; and the University of Cambridge in the United Kingston contributed to this study.

In a newly released study, researchers found that remote and virtual care models can negatively impact small physician offices. Three researchers from University of Colorado Denver conducted the study, which was published in the National Library of Medicine.

The COVID-19 pandemic has accelerated the adoption of remote and virtual care models in both small and large health care facilities around the world. CU Denver researchers Jiban Khuntia, PhD, Rulon Stacey, PhD, and Madhavan Parthasarathy, PhD, initiated this study to assess the perceptions small health care businesses' have regarding the impact of remote and virtual care on their business sustainability during the pandemic.

The team analyzed how well perceptions of virtual care aligned with the current business scenarios of those surveyed. In total, researchers spoke with three different groups of health care facilities across Colorado--82 clinics, 99 small physician offices, and 89 pharmacies.

The study found the perception of virtual health models varied between the three groups. Clinics surveyed believe their virtual care directly affects their current business scenario. Overall, their attitude towards the virtual model was positive. Small physician offices reacted differently to the survey. They believe while virtual care models significantly affect their business scenarios, it mostly comes with negative impacts such as a decrease in revenue. Pharmacies saw no significant effect on their current business scenarios from the virtual model.

"We see small physician offices struggle to keep up with the changes COVID-19 has brought," said Khuntia "While they are ready to adapt to the changes virtual care models bring, the revenue stream isn't what it used to be with in-person visits."

Why is this important?

"If small health care firms cannot compete with the virtual model, they will become nonoperational," said Stacey. "This will damage traditional health services, particularly for critical care delivery and other services that cannot be done virtually."

The current perception small health care businesses have toward remote care will give policy makers a better understanding of the pros and cons of rapidly adopting the remote virtual care model. For small physician offices to surivde, there must be a balance between in-person and virtual care.

Neurological disorders are the number one cause of disability in the world, leading to seven million deaths each year. Yet few treatments exist for these diseases, which progressively diminish a person's ability to move and think.

Now, a new study suggests that some of these neurological disorders share a common underlying thread. Staufen1, a protein that accumulates in the brains of patients with certain neurological conditions, is linked to amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, along with other neurological disorders, including Alzheimer's, Parkinson's, and Huntington's disease, according to University of Utah Health scientists.

The findings connect Staufen1 to the emerging concept that neurodegenerative diseases are linked to malfunctions in the way cells cope with cellular stress. These results, based on laboratory studies of human tissue and mouse models, suggest that targeting Staufen1 could eventually lead to therapeutic interventions for a number of these disorders.

The study appears in Annals of Neurology.

"Neurodegenerative diseases are a major cause of morbidity and mortality," says Stefan Pulst, M.D., Dr. Med, chair of the Department of Neurology at the University of Utah School of Medicine and senior researcher on the study. "Unfortunately, at this time, we have few, if any, disease-modifying therapies. This finding provides new insight into the pathogenesis of these disorders and potentially provides us with a new target for treatment."

In previous research, the scientists found that Staufen1 accumulates in cells of patients with ALS and cerebellar ataxia, a rare condition that causes patients to lose control of movement. They found that Staufen1 binds to a protein that is both a risk factor for ataxia and a risk factor for ALS. Together, along with other proteins, they form dense disease-related clusters called stress granules that can disrupt normal cellular function. However, when Staufen1 was lowered in the brains of mice, it not only improved the pathology of disease but also rid cells of stress granules.

In their new study, Pulst and colleagues sought to determine if Staufen1 overabundance was a factor in the development of other neurological disorders. To do it, they conducted laboratory experiments on skin cells and spinal cord tissues collected from 12 patients with several different neurodegenerative diseases. They also examined the effects of Staufen1 on neurodegeneration in two animal models.

"We found that Staufen1 protein levels were vastly increased in all of the disease models we examined," Pulst says. "In our laboratory animals, levels of this protein were three- to five-fold higher than in control animals. That's not subtle. If a protein is changed that much, it probably isn't good for any cell, particularly a neuron."

Digging deeper, the researchers found that Staufen1 has an important interaction with another protein called mTOR, a master regulator of many functions in the body that plays a key role in a process called autophagy. Autophagy, or "self-digestion," is a self-preservation mechanism that the body uses to remove dysfunctional cells.

The new study suggests that the complex relationship between Staufen1, mTOR, and autophagy could be a driving factor in the onset of several neurogenerative diseases, according to Daniel Scoles, Ph.D., study co-author and associate professor of neurology at U of U Health.

"When Staufen1 is increased, it actually impairs autophagy," Scoles says. "But we also know that autophagy can degrade Staufen1. It's a vicious cycle that can have a bad outcome for patients."

Based on these findings, Pulst and Scoles are hopeful that they can develop a medication to reduce Staufen1 levels in people at risk for sporadic ALS, the most common form of ALS, in which the causes of the disease are unknown.

If lowering Staufen1 is effective for ALS, it could eventually lead to new therapeutic approaches for the treatment of Alzheimer's disease and other Staufen1-related disorders, the researchers say.

Two MIT professors have proposed a new approach to estimating the risks of exposure to Covid-19 under different indoor settings. The guideline they developed suggests a limit for exposure time, based on the number of people, the size of the space, the kinds of activity, whether masks are worn, and the ventilation and filtration rates. Their model offers a detailed, physics-based guideline for policymakers, businesses, schools, and individuals trying to gauge their own risks.

The guideline, appearing this week in the journal PNAS, was developed by Martin .Z. Bazant, professor of chemical engineering and applied mathematics, and John W. M. Bush, professor of applied mathematics. They stress that one key feature of their model, which has received less attention in existing public-health policies, is providing a specific limit for the amount of time a person spends in a given setting.

Their analysis is based on the fact that in enclosed spaces, tiny airborne pathogen-bearing droplets emitted by people as they talk, cough, sneeze, sing, or eat will tend to float in the air for long periods and to be well-mixed throughout the space by air currents. There is now overwhelming evidence, they say, that such airborne transmission plays a major role in the spread of Covid-19. Bush says the study was initially motivated early last year by their concern that many decisions about policies were being guided primarily by the "6-foot rule," which doesn't adequately address airborne transmission in indoor spaces.

Using a strictly quantitative approach based on the best available data, the model produces an estimate of how long, on average, it would take for one person to become infected with the SARS-CoV-2 virus if an infected person entered the space, based on the key set of variables defining a given indoor situation. Rather than a simple yes or no answer about whether a given setting or activity is safe, it provides a guide as to just how long a person could safely expect to engage in that activity, whether it be a few minutes in a store, an hour in a restaurant, or several hours a day in an office or classroom, for example.

"As scientists, we've tried to be very thoughtful and only go with what we see as hard data," Bazant says. "We've really tried to just stick to things we can carefully justify. We think our study is the most rigorous study of this type to date." While new data are appearing every day, and many uncertainties remain about the SARS-CoV-2 virus' transmission, he says, "We feel confident that we've made conservative choices at every point."

Bush adds: "It's a quickly moving field. We submit a paper and the next day a dozen relevant papers come out, so we scramble to incorporate them. It's been like shooting at a moving target." For example, while their model was initially based on the transmissibility of the original strain of SARS-CoV-2 from epidemiological data on the best characterized early spreading events, they have since added a transmissibility parameter, which can be adjusted to account for the higher spreading rates of the new emerging variants. This adjustment is based on how any new strain's transmissibility compares to the original strain; for example, for the U.K. strain, which has been estimated to be 60 percent more transmissible than the original, this parameter would be set at 1.6.

One thing that's clear, they say, is that simple rules, based on distance or capacity limits on certain types of businesses, don't reflect the full picture of the risk in a given setting. In some cases that risk may be higher than those simple rules convey; in others it may be lower. To help people, whether policymakers or individuals, to make more comprehensive evaluations, the researchers teamed with app developer Kasim Khan to put together an open-access mobile app and website where users can enter specific details about a situation -- size of the space, number of people, type of ventilation, type of activity, mask wearing, and the transmissibility factor for the predominant strain in the area at the time -- and receive an estimate of how long it would take, under those circumstances, for one new person to catch the virus if an infected person enters the space.

The calculations were based on inferences made from various mass-spreading events, where detailed data were available about numbers of people and their age range, sizes of the enclosed spaces, kinds of activities (singing, eating, exercising, etc.), ventilation systems, mask wearing, the amount of time spent, and the resulting rates of infections. Events they studied included, for example, the Skagit Valley Chorale in Washington state, where 86 percent of the seniors present became infected at a two-hour choir practice

While their guideline is based on well-mixed air within a given space, the risk would be higher if someone is positioned directly within a focused jet of particles emitted by a sneeze or a shout, for example. But in general the assumption of well-mixed air indoors seems to be consistent with the data from actual spreading events, they say.

"When you look at this guideline for limiting cumulative exposure time, it takes in all of the parameters that you think should be there -- the number of people, the time spent in the space, the volume of the space, the air conditioning rate and so on," Bush says. "All of these things are kind of intuitive, but it's nice to see them appear in a single equation."

While the data on the crucial importance of airborne transmission has now become clear, Bazant says, public health organizations initially placed much more emphasis on handwashing and the cleaning of surfaces. Early in the pandemic, there was less appreciation for the importance of ventilation systems and the use of face masks, which can dramatically affect the safe levels of occupancy, he says.

"I'd like to use this work to establish the science of airborne transmission specifically for Covid-19, by just taking into account all factors, the available data, and the distribution of droplets for different kinds of activities," Bazant says. He hopes the information will help people make informed decisions for their own lives: "If you understand the science, you can do things differently in your own home and your own business and your own school."

Bush offers an example: "My mother is over 90 and lives in an elder care facility. Our model makes it clear that it's useful to wear a mask and open a window -- this is what you have in your control." He was alarmed that his mother was planning to attend an exercise class in the facility, thinking it would be OK because people would be 6 feet apart. As the new study shows, because of the number of people and the activity level, that would actually be a highly risky activity, he says.

Already, since they made the app available in October, Bazant says, they have had about half a million users. Their feedback helped the researchers refine the model further, he says. And it has already helped to influence some decisions about reopening of businesses, he adds. For example, the owner of an indoor tennis facility in Washington state that had been shut down due to Covid restrictions says he was allowed to reopen in January, along with certain other low-occupancy sports facilities, based on an appeal he made based in large part on this guideline and on information from his participation in Bazant's online course on the physics of Covid-19 transmission.

Bazant says that in addition to recommending guidelines for specific spaces, the new tools also provide a way to assess the relative merits of different intervention strategies. For example, they found that while improved ventilation systems and face mask use make a big difference, air filtration systems have a relatively smaller effect on disease spread. And their study can provide guidance on just how much ventilation is needed to reach a particular level of safety, he says.

"Bazant and Bush have provided a valuable tool for estimating (among other things) the upper limit on time spent sharing the air space with others," says Howard Stone, a professor of mechanical and aerospace engineering at Princeton University who was not connected to this work. While such an analysis can only provide a rough estimate, he says the authors "describe this kind of order of magnitude of estimate as a means for helping others judge the situation they might be in and how to minimize their risk. This is particularly helpful since a detailed calculation for every possible space and set of parameters is not possible."

URBANA, Ill. - Australian pineapple, Danish trout, and Midwestern U.S. corn farmers are not often lumped together under the same agricultural umbrella. But they and many others who raise crops and animals face a common problem: excess nitrogen in drainage water. Whether it flows out to the Great Barrier Reef or the Gulf of Mexico, the nutrient contributes to harmful algal blooms that starve fish and other organisms of oxygen.

But there's a simple solution that significantly reduces the amount of nitrogen in drainage water, regardless of the production system or location: denitrifying bioreactors.

"Nitrogen pollution from farms is relevant around the world, from corn and bean farms here in Illinois to sugarcane and pineapple farms in Australia to diverse farms bordered by ditches in Belgium. We're all dealing with this issue. It's really exciting that bioreactors are bringing us together around a potential solution," says Laura Christianson, assistant professor in the Department of Crop Sciences at the University of Illinois and lead author on a new synthesis article accepted for publication in Transactions of the American Society of Agricultural and Biological Engineers (ASABE).

Denitrifying bioreactors come in many shapes and sizes, but in their simplest form, they're trenches filled with wood chips. Water from fields or aquaculture facilities flows through the trench, where bacteria living in wood chip crevices turn nitrate into a harmless gas that escapes into the air.

This edge-of-field conservation practice has been studied for at least a dozen years, but most of what scientists know about nitrogen removal rates is based on laboratory replicas and smaller-scale experimental setups. The USDA's National Resource Conservation Service published a set of standardized bioreactor guidelines in 2015, based in part on Christianson's early field-scale work, and now more and more U.S. farmers are adding bioreactors. They're catching on in other countries, too.

The ASABE article is the first to synthesize the available data from full-size bioreactors on working farms across the world.

"After gathering all the data, the message is bioreactors work. We've shown a 20-40% reduction in nitrate from bioreactors in the Midwest, and now we can say bioreactors around the world are pretty consistent with that," Christianson says.

She adds bioreactors, like all conservation practices, have their limitations, but nitrous oxide emissions aren't one of them.

"People are worried we're just transferring nitrate in water for nitrous oxide, which is a greenhouse gas. We don't know the full story on nitrous oxide with bioreactors yet, but we can say with good confidence they're not creating a huge nitrous oxide problem," she says. "They're just not."

Christianson says farmers frequently ask her about monitoring the water in bioreactors, so she and her co-authors detail the process in the ASABE article. She also partnered with the Illinois Farm Bureau to create a series of step-by-step videos explaining how to test the water.

"For monitoring, there are two parts. You have to know how much water is flowing through the bioreactor and how much nitrogen is in the water," she says.

The short videos, which are aimed at non-researchers such as farmers and water quality volunteers, break the process down into five steps. Christianson notes her students, postdoctoral researchers, and lab staff all pulled together to create the series.

The videos are available at https://go.aces.illinois.edu/MonitoringMagic.

Christianson, who may just be the world's biggest cheerleader for bioreactors, admits the monitoring guidelines and video series are a little self-serving.

"We included recommended monitoring approaches so that more people will build them, and then more people will monitor them. And then we'll have more data to show how well bioreactors work and how we can make them work better."

LA JOLLA, CA--Some survivors of ebolavirus outbreaks make antibodies that can broadly neutralize these viruses--and now, scientists at Scripps Research have illuminated how these antibodies can disable the viruses so effectively. The insights may be helpful for developing effective therapies.

Ebolavirus is a family of often-deadly viruses that includes Ebola virus and many lesser-known viruses such as Bundibugyo virus, Sudan virus and Reston virus.

Structural biologists at Scripps Research used electron microscopy techniques to visualize a set of antibodies that target a key site on these viruses called the "glycan cap." Their research showed that the antibodies work against ebolaviruses using the same three mechanisms to prevent the virus from infecting host cells.

The research, published in Cell Reports, is a step toward the creation of an antibody-based treatment that will be useful against a broad range of ebolaviruses.

"We now understand the molecular basis for these antibodies' abilities to neutralize ebolviruses with broad reactivity against different viral species," says the study's first author Daniel Murin, PhD, a staff scientist in the laboratory of Andrew Ward, PhD.

Ward, a professor in the Department of Integrative Structural and Computational Biology at Scripps Research, says he hopes the work will contribute the development of a "cocktail" of therapeutic antibodies that can save lives by treating many forms of the Ebola virus.

"The goal is to provide doctors in Ebola-prone regions their best weapon yet against these deadly outbreaks," Ward says. "The insights we have gained through our structural studies of the virus show how this may be possible."

Ever-emergent Ebola

The first known ebolavirus, now called Zaire ebolavirus or simply Ebola virus, was identified in 1976, named for the site of an outbreak that year near the Ebola river in what was then Zaire and is now the Democratic Republic of Congo.

Other species have since been added to this family of viruses, including Sudan ebolavirus and Bundibugyo ebolavirus. Ebola viruses colonize African fruit bats, often cause disease in chimpanzees and other non-human primates, and trigger outbreaks in humans every few years, on average. Infected people develop a hemorrhagic syndrome that is fatal in roughly half of untreated cases.

Vaccines against Ebola have been developed recently but have not yet been widely used. And although antibody-based treatments also have been developed, none has been shown effective against a broad range of ebolavirus species.

Nevertheless, studies in recent years have shown that some survivors of Ebola infections carry antibodies that, in lab-dish tests, can neutralize multiple ebolavirus species. A surprisingly high proportion of these broadly neutralizing antibodies target the glycan cap, a sugar-slathered site on a stalk-like protein--called the glycoprotein--that enables Ebola viruses to enter host cells.

In the new study, Murin and Ward, along with their colleagues in the James Crowe Lab at Vanderbilt University where the antibodies were isolated, used electron microscopy to analyze a set of glycan cap-targeting antibodies from survivors of various ebolaviruses. Their aim was to understand better how these antibodies target the virus so effectively.

Three ways to defeat the virus

Their analysis suggested that the most broadly effective of these glycan cap-targeting antibodies hit the same vulnerable site on the glycan cap, allowing them to thwart viral infectivity in three ways.

First, the antibody displaces a long viral structure near the glycan cap in a way that destabilizes the entire viral glycoprotein structure, sometimes causing it to fall apart.

Second, the glycan cap antibody--when it binds to its target site--can block a key event in the infection process, in which an enzyme called a cathepsin cleaves off the glycan cap. Blocking this cleavage event blocks the glycoprotein's ability to enter host cells.

Finally, the glycan cap antibody, by displacing the loose structure near the glycan cap, enables another type of neutralizing antibody to bind to a separate vulnerable site on the virus. Thus, a glycan cap antibody can "synergize" with another antibody to hit the virus significantly harder than either antibody does alone.

The scientists also determined the key genetic elements that allow glycan-cap antibodies to thwart ebolaviruses in these three ways.

Now that they have illuminated how these broadly neutralizing antibodies work, Ward, Murin and colleagues are testing them as parts of a next-generation antibody cocktail that they hope will be able to treat the Zaire, Sudan and Bundibugyo ebolaviruses.