Culture

Scientists have long debated the respiratory workings of sea scorpions, but a new discovery by a West Virginia University geologist concludes that these largely aquatic extinct arthropods breathed air on land.

James Lamsdell dug into the curious case of a 340 million-year-old sea scorpion, or eurypterid, originally from France that had been preserved at a Glasgow, Scotland museum for the last 30 years.

An assistant professor of geology in the Eberly College of Arts and Sciences, Lamsdell had read about the “strange specimen” 25 years ago while conducting his doctoral studies. Existing research suggested it would occasionally go on land.

Yet nothing was known on whether it could breathe air. The closest living relative to the eurypterid is the horseshoe crab, which lays eggs on land but is unable to breathe above water.

These details puzzled Lamsdell through the years until he reached out to a colleague, Victoria McCoy at the University of Wisconsin-Milwaukee, and asked, “Do you have access to a CT scanner?”

“We wondered if we could apply new technology to look further into what was preserved of this specimen,” said Lamsdell, who heads a paleobiology lab at WVU. “I like the science and detective work that goes into research. And this was a cold case where we knew there was potential evidence.”

Through computed tomography (CT) imaging, Lamsdell and his team found that evidence, which is published in Current Biology.

Researchers managed to study the respiratory organs of the three-dimensional eurypterid, leading to two findings that stood out to Lamsdell. First, he noticed that each gill on the sea scorpion was composed of a series of plates. But the back contained fewer plates than the front, prompting researchers to question how it could even breathe.

Then they zeroed in on pillars connecting the different plates of the gill, which are seen in modern scorpions and spiders, Lamsdell said. These pillars, or small beams of tissue, are called trabeculae.

“That props the gills apart so they don’t collapse when out of water,” Lamsdell explained. “It’s something that modern arachnids still have. Finding that was the final indication.

“The reason we think they were coming onto land was to move between pools of water. They could also lay eggs in more sheltered, safer environments and migrate back into the open water.”

The discovery of air-breathing structures in the eurypterids indicate that terrestrial characteristics occurred in the arachnid stem lineage, the researchers wrote, suggesting that the ancestor of arachnids were semi-terrestrial.

In addition to Lamsdell and McCoy, co-authors include Opal Perron-Feller of Oberlin College and Melanie Hopkins of the American Museum of Natural History.

Now that Lamsdell has cracked the case living in the back of his head for 20-plus years, he believes there’s more to unearth from the fossil. He noted that the sea scorpion’s back legs expand into a paddle shape, which he suspects would have been used to swim. The bases of their legs also had spikes that ground up food for them that they maneuvered into their mouths, Lamsdell added.

“One of the things that would be really cool to do is to flesh out this model and try to reconstruct exactly how the legs could move and how they were positioned,” Lamsdell said, “like reconstructing the fossil as a living animal.”

Citation: ‘Air Breathing in an Exceptionally Preserved 340-Million-Year-Old Sea Scorpion’

Journal

Current Biology

Leesburg, VA, September 10, 2020--According to ARRS' American Journal of Roentgenology (AJR), artificial intelligence (AI) predictive analytics performed moderately well in solving complex multifactorial operational problems--outpatient MRI appointment no-shows, especially--using a modest amount of data and basic feature engineering.

"Such data may be readily retrievable from frontline information technology systems commonly used in most hospital radiology departments, and they can be readily incorporated into routine workflow practice to improve the efficiency and quality of health care delivery," wrote lead author Le Roy Chong of Singapore's Changi General Hospital.

To train and validate their model, Chong and colleagues extracted records of 32,957 outpatient MRI appointments scheduled between January 2016 and December 2018 from their institution's radiology information system, while acquiring a further holdout test set of 1,080 records from January 2019. Overall, the no-show rate was 17.4%.

After evaluating various machine learning predictive models developed with widely used open-source software tools, Chong and team deployed a decision tree-based ensemble algorithm that uses a gradient boosting framework: XGBoost, version 0.80 [Tianqi Chen].

As Chong et al. explained, "the simple intervention measure of using telephone call reminders for patients with the top 25% highest risk of an appointment no-show as predicted by the model was implemented over 6 months."

Six months after deployment, the no-show rate of the predictive model was 15.9%, compared with 19.3% in the preceding 12-month preintervention period--corresponding to a 17.2% improvement from the baseline no-show rate (p

"We believe that the main strength of the present study lies in its empirical approach, given the lack of published literature quantifying the impact of actual workflow implementation, with previous studies postulating the potential benefits of applying machine learning techniques to this problem," the authors of this AJR article concluded. "The aim of our study was not to produce a highly complex model but, rather, to produce one that could be developed relatively quickly, would require minimal data processing, and would be readily deployable in workflow practice for quality improvement."

The ocean plays an invaluable role in capturing carbon dioxide (CO2) from the atmosphere, taking in somewhere between five to 12 gigatons (billion tons) annually. Due to limited research, scientists aren't sure exactly how much carbon is captured and stored--or sequestered--by the ocean each year or how increasing CO2 emissions will affect this process in the future.

A new paper published in the journal Science of the Total Environment from the Woods Hole Oceanographic Institution (WHOI) puts an economic value on the benefit of research to improve knowledge of the biological carbon pump and reduce the uncertainty of ocean carbon sequestration estimates.

Using a climate economy model that factors in the social costs of carbon and reflects future damages expected as a consequence of a changing climate, lead author Di Jin of WHOI's Marine Policy Center places the value of studying ocean carbon sequestration at $500 billion.

"The paper lays out the connections between the benefit of scientific research and decision making," says Jin. "By investing in science, you can narrow the range of uncertainty and improve a social cost-benefit assessment."

Better understanding of the ocean's carbon sequestration capacity will lead to more accurate climate models, providing policymakers with the information they need to establish emissions targets and make plans for a changing climate, Jin adds.

With co-authors Porter Hoagland and Ken Buesseler, Jin builds a case for a 20-year scientific research program to measure and model the ocean's biological carbon pump, the process by which atmospheric carbon dioxide is transported to the deep ocean through the marine food web.

The biological carbon pump is fueled by tiny plant-like organisms floating on the ocean surface called phytoplankton, which consume carbon dioxide in the process of photosynthesis. When the phytoplankton die or are eaten by larger organisms, the carbon-rich fragments and fecal matter sink deeper into the ocean, where they are eaten by other creatures or buried in seafloor sediments, which helps decrease atmospheric carbon dioxide and thus reduces global climate change.

Rising carbon dioxide levels in the atmosphere, a result of human activity such as burning fossil fuels, warms the planet by trapping heat from the sun and also dissolves into seawater, lowering the pH of the ocean, a phenomenon known as ocean acidification. A warmer, more acidic ocean could weaken the carbon pump, causing atmospheric temperatures to rise--or it could get stronger, with the opposite effect.

"When we try to predict what the world is going to look like, there's great uncertainty," says Buesseler, a WHOI marine chemist. "Not only do we not know how big this pump is, we don't know whether it will remove more or less carbon dioxide in the future. We need to make progress to better understand where we're headed, because the climate affects all of humanity."

Buesseler added that efforts like WHOI's Ocean Twilight Zone initiative and NASA's EXport Processes in the global Ocean from RemoTe Sensing (EXPORTS) program are making important strides in understanding the ocean's role in the global carbon cycle, but this research needs to be vastly scaled up in order to develop predictive models such as those used by the Intergovernmental Panel on Climate Change (IPCC). Current IPCC models do not account for change in the ocean's ability to take up carbon, which Buesseler said affects their accuracy.

Though the paper's assessment doesn't account for the cost of a global research program, Buesseler said that investment would be a small fraction of the $500 billion expected benefit. The authors warn that this savings could also be viewed as a cost to society if the research does not lead to policy decisions that mitigate the effects of climate change.

"Just like a weather forecast that helps you decide whether or not to bring an umbrella, you use your knowledge and experience to make a decision based on science," Jin says. "If you hear it's going to rain and you don't listen, you will get wet."

It is established that matter can transition between different phases when certain parameters, such as temperature, are changed. Although phase transitions are common (like water turning into ice in a freezer), the dynamics that govern these processes are highly complex and constitute a prominent problem in the field of nonequilibrium physics.

When a system undergoes a phase transition, matter in the new phase has many possible energetically equal "configurations" to adopt. In these cases, different parts of the system adopt different configurations over regions called "domains." The interfaces between these domains are known as topological defects and reducing the number of these defects formed can be immensely valuable in many applications.

One common strategy to reduce defects is easing the system through the phase transition slowly. In fact, according to the "Kibble-Zurek" mechanism (KZM), it is predicted that the average number of defects and the driving time of the phase transition follow a universal power law. However, experimentally testing the KZM in a quantum system has remained a coveted goal.

In a recent study published in Physical Review Research, a team of scientists led by Professor Emeritus Hidetoshi Nishimori from Tokyo Institute of Technology, Japan, probed the validity of the KZM in two commercially available quantum annealers, a type of quantum computer designed for solving complex optimization problems. These devices, known as D-Wave annealers, can recreate controllable quantum systems and control their evolution over time, providing a suitable experimental testbed for the KZM.

First, the scientists checked whether the "power law" between the average number of defects and the annealing time (driving time of the phase transition) predicted by the KZM held for a quantum magnetic system called the "one-dimensional transverse-field Ising model." This model represents the orientations (spins) of a long chain of "magnetic dipoles," where homogenous regions are separated by defects seen as neighboring spins pointing in incorrect directions.

While the original prediction of the KZM regarding the average number of defects was valid in this system, the scientists took it a step further: although this extension of the KZM was originally intended for a completely "isolated" quantum system unaffected by external parameters, they found good agreement between its predictions and their experimental results even in the D-Wave annealers, which are "open" quantum systems.

Excited by these results, Prof Nishimori remarks: "Our work provides the first experimental test of universal critical dynamics in a many-body open quantum system. It also constitutes the first test of certain physics beyond the original KZM, providing strong experimental evidence that the generalized theory holds beyond the regime of validity theoretically established."

This study showcases the potential of quantum annealers to perform simulations of quantum systems and also helps gain insight on other areas of physics. In this regard, Prof Nishimori states: "Our results leverage quantum annealing devices as platforms to test and explore the frontiers of nonequilibrium physics. We hope our work will motivate further research combining quantum annealing and other universal principles in nonequilibrium physics." Hopefully, this study will also promote the use of quantum annealers in experimental physics. After all, who doesn't love finding a new use for a tool?

MIT researchers have developed a wireless, private way to monitor a person's sleep postures -- whether snoozing on their back, stomach, or sides -- using reflected radio signals from a small device mounted on a bedroom wall.

The device, called BodyCompass, is the first home-ready, radio-frequency-based system to provide accurate sleep data without cameras or sensors attached to the body, according to Shichao Yue, who will introduce the system in a presentation at the UbiComp 2020 conference on Sept. 15. The PhD student has used wireless sensing to study sleep stages and insomnia for several years.

"We thought sleep posture could be another impactful application of our system" for medical monitoring, says Yue, who worked on the project under the supervision of Professor Dina Katabi in the MIT Computer Science and Artificial Intelligence Laboratory. Studies show that stomach sleeping increases the risk of sudden death in people with epilepsy, he notes, and sleep posture could also be used to measure the progression of Parkinson's disease as the condition robs a person of the ability to turn over in bed.

In the future, people might also use BodyCompass to keep track of their own sleep habits or to monitor infant sleeping, Yue says: "It can be either a medical device or a consumer product, depending on needs."

Other authors on the conference paper, published in the Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, include graduate students Yuzhe Yang and Hao Wang, and Katabi Lab affiliate Hariharan Rahul. Katabi is the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science at MIT.

Restful reflections

BodyCompass works by analyzing the reflection of radio signals as they bounce off objects in a room, including the human body. Similar to a Wi-Fi router attached to the bedroom wall, the device sends and collects these signals as they return through multiple paths. The researchers then map the paths of these signals, working backward from the reflections to determine the body's posture.

For this to work, however, the scientists needed a way to figure out which of the signals were bouncing off the sleeper's body, and not bouncing off the mattress or a nightstand or an overhead fan. Yue and his colleagues realized that their past work in deciphering breathing patterns from radio signals could solve the problem.

Signals that bounce off a person's chest and belly are uniquely modulated by breathing, they concluded. Once that breathing signal was identified as a way to "tag" reflections coming from the body, the researchers could analyze those reflections compared to the position of the device to determine how the person was lying in bed. (If a person was lying on her back, for instance, strong radio waves bouncing off her chest would be directed at the ceiling and then to the device on the wall.) "Identifying breathing as coding helped us to separate signals from the body from environmental reflections, allowing us to track where informative reflections are," Yue says.

Reflections from the body are then analyzed by a customized neural network to infer how the body is angled in sleep. Because the neural network defines sleep postures according to angles, the device can distinguish between a sleeper lying on the right side from one who has merely tilted slightly to the right. This kind of fine-grained analysis would be especially important for epilepsy patients for whom sleeping in a prone position is correlated with sudden unexpected death, Yue says.

BodyCompass has some advantages over other ways of monitoring sleep posture, such as installing cameras in a person's bedroom or attaching sensors directly to the person or their bed. Sensors can be uncomfortable to sleep with, and cameras reduce a person's privacy, Yue notes. "Since we will only record essential information for detecting sleep posture, such as a person's breathing signal during sleep," he says, "it is nearly impossible for someone to infer other activities of the user from this data."

An accurate compass

The research team tested BodyCompass' accuracy over 200 hours of sleep data from 26 healthy people sleeping in their own bedrooms. At the start of the study, the subjects wore two accelerometers (sensors that detect movement) taped to their chest and stomach, to train the device's neural network with "ground truth" data on their sleeping postures.

BodyCompass was most accurate -- predicting the correct body posture 94 percent of the time -- when the device was trained on a week's worth of data. One night's worth of training data yielded accurate results 87 percent of the time. BodyCompass could achieve 84 percent accuracy with just 16 minutes' worth of data collected, when sleepers were asked to hold a few usual sleeping postures in front of the wireless sensor.

Along with epilepsy and Parkinson's disease, BodyCompass could prove useful in treating patients vulnerable to bedsores and sleep apnea, since both conditions can be alleviated by changes in sleeping posture. Yue has his own interest as well: He suffers from migraines that seem to be affected by how he sleeps. "I sleep on my right side to avoid headache the next day," he says, "but I'm not sure if there really is any correlation between sleep posture and migraines. Maybe this can help me find out if there is any relationship."

For now, BodyCompass is a monitoring tool, but it may be paired someday with an alert that can prod sleepers to change their posture. "Researchers are working on mattresses that can slowly turn a patient to avoid dangerous sleep positions," Yue says. "Future work may combine our sleep posture detector with such mattresses to move an epilepsy patient to a safer position if needed."

Astronomers have discovered that there may be a missing ingredient in our cosmic recipe of how dark matter behaves.

They have uncovered a discrepancy between the theoretical models of how dark matter should be distributed in galaxy clusters, and observations of dark matter's grip on clusters.

Dark matter does not emit, absorb, or reflect light. Its presence is only known through its gravitational pull on visible matter in space. Therefore, dark matter remains as elusive as Alice in Wonderland's Cheshire Cat - where you only see its grin (in the form of gravity) but not the animal itself.

One way astronomers can detect dark matter is by measuring how its gravity distorts space, an effect called gravitational lensing.

Researchers found that small-scale concentrations of dark matter in clusters produce gravitational lensing effects that are 10 times stronger than expected. This evidence is based on unprecedentedly detailed observations of several massive galaxy clusters by NASA's Hubble Space Telescope and the European Southern Observatory's Very Large Telescope (VLT) in Chile.

Galaxy clusters, the most massive structures in the universe composed of individual member galaxies, are the largest repositories of dark matter. Not only are they held together largely by dark matter's gravity, the individual cluster galaxies are themselves replete with dark matter. Dark matter in clusters is therefore distributed on both large and small scales.

"Galaxy clusters are ideal laboratories to understand if computer simulations of the universe reliably reproduce what we can infer about dark matter and its interplay with luminous matter," said Massimo Meneghetti of the INAF (National Institute for Astrophysics)-Observatory of Astrophysics and Space Science of Bologna in Italy, the study's lead author.

"We have done a lot of careful testing in comparing the simulations and data in this study, and our finding of the mismatch persists," Meneghetti continued. "One possible origin for this discrepancy is that we may be missing some key physics in the simulations."

Priyamvada Natarajan of Yale University in New Haven, Connecticut, one of the senior theorists on the team, added, "There's a feature of the real universe that we are simply not capturing in our current theoretical models. This could signal a gap in our current understanding of the nature of dark matter and its properties, as these exquisite data have permitted us to probe the detailed distribution of dark matter on the smallest scales."

The team's paper will appear in the Sept. 11 issue of the journal Science.

The distribution of dark matter in clusters is mapped via the bending of light, or the gravitational lensing effect, they produce. The gravity of dark matter magnifies and warps light from distant background objects, much like a funhouse mirror, producing distortions and sometimes multiple images of the same distant galaxy. The higher the concentration of dark matter in a cluster, the more dramatic its light bending.

Hubble's crisp images, coupled with spectra from the VLT, helped the team produce an accurate, high-fidelity dark-matter map. They identified dozens of multiply imaged, lensed, background galaxies. By measuring the lensing distortions, astronomers could trace out the amount and distribution of dark matter.

The three key galaxy clusters used in the analysis, MACS J1206.2-0847, MACS J0416.1-2403, and Abell S1063, were part of two Hubble surveys: The Frontier Fields and the Cluster Lensing And Supernova survey with Hubble (CLASH) programs.

To the team's surprise, the Hubble images also revealed smaller-scale arcs and distorted images nested within the larger-scale lens distortions in each cluster's core, where the most massive galaxies reside.

The researchers believe that the embedded lenses are produced by the gravity of dense concentrations of dark matter associated with individual cluster galaxies. Dark matter's distribution in the inner regions of individual galaxies is known to enhance the cluster's overall lensing effect.

Follow-up spectroscopic observations added to the study by measuring the velocity of the stars orbiting inside several of the cluster galaxies. "Based on our spectroscopic study, we were able to associate the galaxies with each cluster and estimate their distances," said team member Piero Rosati of the University of Ferrara in Italy.

"The stars' speed gave us an estimate of each individual galaxy's mass, including the amount of dark matter," added team member Pietro Bergamini of the INAF-Observatory of Astrophysics and Space Science in Bologna, Italy.

The team compared the dark-matter maps with samples of simulated galaxy clusters with similar masses, located at roughly the same distances as the observed clusters. The clusters in the computer simulations did not show the same level of dark-matter concentration on the smallest scales - the scales associated with individual cluster galaxies as seen in the universe.

The team looks forward to continuing their stress-testing of the standard dark-matter model to pin down its intriguing nature.

COLUMBUS, Ohio -- Almost seven in 10 Americans would be interested in receiving a COVID-19 vaccine when one becomes available, according to a new study. But researchers say there are concerning gaps in interest, particularly among Black Americans, who suffer disproportionately from the virus.

Researchers from The Ohio State University surveyed more than 2,000 Americans in May, asking them about their willingness to be vaccinated and 11 factors that could influence that decision. They found that 1,374 out of 2006 people in the survey, 69%, said they would "definitely" or "probably" get a vaccine. The survey found that 17% were "not sure" and 14% were "probably or "definitely" not willing.

The study, one of the first estimates of COVID-19 vaccine acceptance in the U.S., appears online in the journal Vaccine.

Lead researcher Paul Reiter, an associate professor of health behavior and health promotion, said he suspected there would be higher-than-normal interest in this vaccine, considering the nature of the pandemic and the severity of illness many people have experienced.

"The interest here is higher than what we typically see for flu vaccine and other vaccines where there is a strong public health need for widespread protection," he said.

The strongest predictors of whether someone said they'd accept a vaccine were how well the vaccine works and whether their health care provider would recommend it. Individuals' perceived personal health threat from COVID-19 also played strongly into their willingness to be vaccinated, the researchers found.

"That aligns with what we see in public health in a variety of areas -- if someone perceives themselves to be at a higher risk of a health issue, that's going to make them more likely to engage in the health behavior, in this case vaccination," Reiter said.

One of the more unexpected findings in this study - and something that isn't typical of public health research - is the correlation between political affiliation and willingness to adopt a public health intervention, Reiter said. Respondents who identified as liberal or moderate were significantly more likely to accept a vaccine.

"COVID-19 has turned into a political issue in many cases, and I think that some people just pick their side based on that, without much research," he said. "We've seen that with mask wearing. It's a promising public health intervention, but it's turned into a political powder keg."

The most worrisome finding was among Black survey respondents, as only 55% said they were willing to get a vaccine.

"Given the disproportionate burden of COVID-19 infection and death among Black Americans, it's concerning to see that Black survey participants had less interest in a vaccine," Reiter said.

"I think there are likely several factors at play, including access to care and trust in health care and potential socioeconomic barriers."

Reducing such barriers is important since only 35% of participants in the study would pay $50 or more out-of-pocket for a COVID-19 vaccine, Reiter said.

As of the first week of September, 10 states had indicated plans to offer free vaccines when they become available, according to KFF (formerly known as the Kaiser Family Foundation.)

Reiter said public health leaders and policymakers can look to this study as they shape efforts to communicate the benefits (and any risks) of a COVID-19 vaccine, once one is approved for general use.

"You hear a lot of talk of vaccination and the benefits of herd immunity, the idea that when enough people have resistance to a virus it reduces the threat to the entire population. At 70%, we may or may not get there," Reiter said.

That makes it especially important to work toward educational efforts, the elimination of obstacles and other strategies to increase the chances of vaccination among those who face increased risks of severe illness or death. If the vaccine against COVID-19 requires more than one dose, it will present even more challenges, he said -- a reality that has been made clear in recent years with efforts to fully vaccinate young people against HPV to help prevent cancer. The HPV vaccine requires at least two doses, and three when given later in the teen years.

Though the survey was conducted four months ago, Reiter said he doesn't expect much has changed in terms of public perception.

"As we get closer to a vaccine becoming available, factors that could further affect the public's interest will include cost and the number of doses required," he said.

Observations by the NASA/ESA Hubble Space Telescope and the European Southern Observatory's Very Large Telescope (VLT) in Chile have found that something may be missing from the theories of how dark matter behaves. This missing ingredient may explain why researchers have uncovered an unexpected discrepancy between observations of the dark matter concentrations in a sample of massive galaxy clusters and theoretical computer simulations of how dark matter should be distributed in clusters. The new findings indicate that some small-scale concentrations of dark matter produce lensing effects that are 10 times stronger than expected.

Dark matter is the invisible glue that keeps stars, dust, and gas together in a galaxy. This mysterious substance makes up the bulk of a galaxy's mass and forms the foundation of our Universe's large-scale structure. Because dark matter does not emit, absorb, or reflect light, its presence is only known through its gravitational pull on visible matter in space. Astronomers and physicists are still trying to pin down what it is.

Galaxy clusters, the most massive and recently assembled structures in the Universe, are also the largest repositories of dark matter. Clusters are composed of individual member galaxies that are held together largely by the gravity of dark matter.

"Galaxy clusters are ideal laboratories in which to study whether the numerical simulations of the Universe that are currently available reproduce well what we can infer from gravitational lensing," said Massimo Meneghetti of the INAF-Observatory of Astrophysics and Space Science of Bologna in Italy, the study's lead author [1].

"We have done a lot of testing of the data in this study, and we are sure that this mismatch indicates that some physical ingredient is missing either from the simulations or from our understanding of the nature of dark matter," added Meneghetti.

"There's a feature of the real Universe that we are simply not capturing in our current theoretical models," added Priyamvada Natarajan of Yale University in Connecticut, USA, one of the senior theorists on the team. "This could signal a gap in our current understanding of the nature of dark matter and its properties, as these exquisite data have permitted us to probe the detailed distribution of dark matter on the smallest scales."

The distribution of dark matter in clusters is mapped by measuring the bending of light -- the gravitational lensing effect -- that they produce. The gravity of dark matter concentrated in clusters magnifies and warps light from distant background objects. This effect produces distortions in the shapes of background galaxies which appear in images of the clusters. Gravitational lensing can often also produce multiple images of the same distant galaxy.

The higher the concentration of dark matter in a cluster, the more dramatic its light-bending effect. The presence of smaller-scale clumps of dark matter associated with individual cluster galaxies enhances the level of distortions. In some sense, the galaxy cluster acts as a large-scale lens that has many smaller lenses embedded within it.

Hubble's crisp images were taken by the telescope's Wide Field Camera 3 and Advanced Camera for Surveys. Coupled with spectra from the European Southern Observatory's Very Large Telescope (VLT), the team produced an accurate, high-fidelity, dark-matter map. By measuring the lensing distortions astronomers could trace out the amount and distribution of dark matter. The three key galaxy clusters, MACS J1206.2-0847, MACS J0416.1-2403, and Abell S1063, were part of two Hubble surveys: The Frontier Fields and the Cluster Lensing And Supernova survey with Hubble (CLASH) programs.

To the team's surprise, in addition to the dramatic arcs and elongated features of distant galaxies produced by each cluster's gravitational lensing, the Hubble images also revealed an unexpected number of smaller-scale arcs and distorted images nested near each cluster's core, where the most massive galaxies reside. The researchers believe the nested lenses are produced by the gravity of dense concentrations of matter inside the individual cluster galaxies. Follow-up spectroscopic observations measured the velocity of the stars orbiting inside several of the cluster galaxies to therby pin down their masses.

"The data from Hubble and the VLT provided excellent synergy," shared team member Piero Rosati of the Università degli Studi di Ferrara in Italy, who led the spectroscopic campaign. "We were able to associate the galaxies with each cluster and estimate their distances."

"The speed of the stars gave us an estimate of each individual galaxy's mass, including the amount of dark matter," added team member Pietro Bergamini of the INAF-Observatory of Astrophysics and Space Science in Bologna, Italy.

By combining Hubble imaging and VLT spectroscopy, the astronomers were able to identify dozens of multiply imaged, lensed, background galaxies. This allowed them to assemble a well-calibrated, high-resolution map of the mass distribution of dark matter in each cluster.

The team compared the dark-matter maps with samples of simulated galaxy clusters with similar masses, located at roughly the same distances. The clusters in the computer model did not show any of the same level of dark-matter concentration on the smallest scales -- the scales associated with individual cluster galaxies.

"The results of these analyses further demonstrate how observations and numerical simulations go hand in hand", said team member Elena Rasia of the INAF-Astronomical Observatory of Trieste, Italy.

"With high-resolution simulations, we can match the quality of observations analysed in our paper, permitting detailed comparisons like never before," added Stefano Borgani of the Università degli Studi di Trieste, Italy.

Astronomers, including those of this team, look forward to continuing to probe dark matter and its mysteries in order to finally pin down its nature.

Aerosols are tiny solid or liquid particles suspended in the air. They influence the climate by absorbing or scattering sunlight and serving as cloud condensation nuclei. Moreover, they can impact human well-being through adverse health effects of fine particulate matter.

A large fraction of particulate matter consists of nitrate, sulfate, and ammonium ions. The formation of these major aerosol components is strongly influenced by aerosol acidity, which varies widely between different regions with aerosol pH values ranging from ~1 to ~6. The drivers of these large variations, however, are not clear.

Researchers have now discovered how important the water content and total mass concentration of aerosol particles are for their acidity. A team led by Yafang Cheng and Hang Su from the Max Planck Institute for Chemistry discovered that these factors can be even more important than the dry particle composition. For populated continental areas with high anthropogenic emissions of ammonia from agriculture, traffic, and industry, they found that aerosol pH can be efficiently buffered and stabilized at different levels by the conjugate acid-base pair of ammonium ions and ammonia (NH4+/NH3).

The investigations now published in the interdisciplinary research journal `Science´ started with the question if and how the pH of aerosols is buffered in different continental regions. To address this issue, the scientists from Mainz developed a new theory of multiphase buffering in aerosols, analyzed atmospheric measurement data and performed global model simulations of aerosol composition and acidity.

"It turned out that the acid-base pair NH4+/NH3 is buffering the aerosol pH over most populated continental areas, even though the acidity may vary by multiple pH units", says Yafang Cheng, Minerva Research Group leader at the Max Planck Institute for Chemistry. "Variations in water content are responsible for 70-80 percent of global variability in aerosol pH in ammonia-buffered regions, which was not previously known and can be explained by our new multiphase buffer theory", she adds.

In particular, the Max Planck researchers used their model to compare aerosol composition and acidity for two very different geographic regions and conditions. In the southeastern United States during summer, the air is clean, and the few atmospheric aerosol particles contain little water at pH values around ~1, whereas there are typically high aerosol concentrations with high water content at pH values around ~5 over the North China Plain in winter. "We find that these large differences in aerosol pH are primarily due to differences in aerosol loading and water content rather than differences in the nitrate content as assumed in earlier studies," explains Guangjie Zheng, a postdoc in Yafang Cheng's group.

"Globally, ~70% of urban areas are in the ammonia-buffered regime", summarizes Hang Su, scientific group leader in the Multiphase Chemistry Department of the institute. "Thus, the newly discovered multiphase buffer mechanism is important to understand haze formation and aerosol effects on human health and climate in the Anthropocene."

The results of the team around Cheng and Su not only imply that aerosol pH and atmospheric multiphase chemistry are strongly affected by the pervasive human influence on ammonia emissions and the nitrogen cycle in the Anthropocene. They also improve the understanding how air pollution develops and thus provide an important approach for possible control measures.

Ever since the first cases of a mysterious disease in the early 1980s exploded into the HIV/AIDS pandemic, researchers have been searching for ways to outsmart the deadly virus. Now thanks to anti-retroviral therapy, people living with HIV can live relatively normal lifespans--as long as they take their medications every day.

"If they ever stop, in short order the virus rebounds and resets at the high levels seen before starting-- and that seems to be the case even after decades of therapy," says Mark Painter, Ph.D., a graduate student in the University of Michigan Medical School's department of microbiology and immunology.

The reason is that HIV can hide inside the human genome, lying dormant and ready to emerge at any time. Because of this, a true cure for HIV relies on waking the latent virus and eliminating it before it has a chance to again take hold of the body's cells, an approach known as shock and kill.

Working with a team under the direction of Kathleen Collins, M.D., Ph.D., they set out to find a weapon to kill HIV by targeting a protein called Nef. In 1998, Collins, who is a professor of internal medicine and microbiology and immunology, discovered that HIV uses Nef to evade the body's immune system by overriding the functioning of a protein on a cell's surface that lets immune cells know that the cell is infected and in need of elimination. By disabling this protein, called MHC-I, infected cells are able to proliferate.

The research tried determine if there was an FDA-approved drug or molecule already on the market that could override Nef, restore the functioning of MHC-I and allow the body's own immune system, specifically cells known as cytotoxic T lymphocytes, to recognize the HIV-infected cells and destroy them.

"We started out screening a library of 200,000 small molecules and found none inhibited Nef," says Painter. Undeterred, they approached David Sherman, Ph.D. of the U-M Life Sciences Institute, whose lab studies the biosynthesis of natural products from microbes, such as cyanobacteria.

"Often synthetic molecules have quite a low molecular weight, meaning they are fairly small. And if you need to disrupt a large protein surface or interface, such as with Nef, a small molecule won't work well or at all," explains Sherman. "A natural products library like the one at the LSI, on the other hand, is going to have molecules with a large range of weights and sizes."

After screening approximately 30,000 molecules, they discovered that a class of antibiotic molecules called pleicomacrolides inhibited Nef.

"Pleicomacrolides are widely used in lab experiments when you want to shut down the lysosome. Because of this, they are considered toxic and risky to use as drugs," says Painter. The lysosome is an essential cell organelle used to break down worn out cell parts, viruses and bacteria.

However, the team determined that a pleicomacrolide called concanamycin A inhibits Nef at much lower concentrations than those needed to inhibit the lysosome. "As a lead compound for drug development, it's fairly exciting because we can use a very low dose, and inhibit Nef without short-term toxicity to the cells," said Painter.

In a proof of concept experiment, they treated HIV-infected, Nef expressing cells with concanamycin A and found that cytotoxic T cells were able to clear the infected T cells.

"It's been extremely gratifying for this project, which began in my lab over a decade ago to finally come to fruition. I had hoped we would find something that worked as well as this compound does but it was never a guarantee that we would actually be successful. This type of research is risky but extremely important because of the potential reward," says Collins. But, she adds, the molecule is not yet ready to be used as a drug for treatment of HIV infected people. "More research will be needed to optimize the compound. We will need to further separate the potent Nef inhibitory activity from the more toxic effect on lysosomal function to make it a viable therapy."

Collins, Painter and their colleagues are continuing work on refining the chemistry of concanamycin A to make it even more viable as a potential therapy. When combined with ART and future treatments that shock latent HIV awake, Painter notes the therapy could be used to clear any remaining virus, essentially curing HIV.

CHAPEL HILL, NC - September 10, 2020 - UNC-Chapel Hill researchers have, for the first time, determined the high-resolution structure of a key DNA-sensing protein in the innate immune system called cGAS while it is bound to the nucleosome - the all-important unit of DNA packaging inside a cell's nucleus.

This research, published in Science, reveals in detail how the nucleosomes inside our cells block cGAS from unintentionally triggering the body's innate immune response to our own DNA. The work was led by Qi Zhang, PhD, associate professor of biochemistry and biophysics at the UNC School of Medicine, and Robert McGinty, MD, PhD, assistant professor of chemical biology and medicinal chemistry at the UNC Eshelman School of Pharmacy.

"Detecting and responding to foreign DNA from bacterial and viral pathogens is one of the most fundamental mechanisms for host defense," said Zhang, co-senior author. "A deeper understanding of functions and regulations of this important DNA sensor will have profound impacts on both basic research and translational development of cGAS-targeted therapeutics crucial to the betterment of human health."

McGinty, co-senior author, said, "This work was enabled by recent advances in cryo-electron microscopy technology that allows scientists, like those on our team, to observe the protein machines inside our cells with unprecedented clarity. By seeing how these proteins function normally, we can gain insights into how to manipulate their functions to treat diseases."

In the mammalian innate immune system, the protein cyclic GMP-AMP synthase (cGAS) detects foreign or damaged "self" DNAs. Upon DNA detection, cGAS synthesizes cyclic GMP-AMP (cGAMP), the second messenger molecule that activates the cGAS-STING signaling pathway to fight infections, inflammatory diseases, and cancers.

Because cGAS is a "universal" DNA sensor, it must be regulated to differentiate pathogenic DNA from the body's own healthy DNA to avoid any unintended immune responses. Previous research has shown that cGAS is enriched inside the nucleus where our genomic DNA is stored, but it remains a mystery as how cGAS ignores our own healthy DNA.

Using the UNC School of Medicine state-of-the-art Cryo-Electron Microscopy Core Facility, which was established in 2019, the Zhang and McGinty labs determined a 3.3Å-resolution cryo-EM structure of cGAS in complex with the nucleosome. The structure shows that cGAS employs two conserved amino acids to anchor to a negatively charged patch on the nucleosome surface. These protein-protein interactions allow the nucleosome to occupy a critical DNA sensing surface on cGAS and prevent cGAS from entering its functionally active DNA-bound state. Together with mutagenesis and functional assays, this study provides a near-atomic resolution depiction of how cGAS maintains the resting, inhibited state in the nucleus.

"These findings reshape the current paradigm of cGAS regulation and exemplify the role of the nucleosome in regulating diverse protein functions," said McGinty, who holds a joint faculty appointment at the UNC School of Medicine.

Zhang added, "Biomedical scientists will be able to apply our research to fields such as immunology, cancer biology, and gene regulation, as well as to drug discovery for infections, inflammatory diseases, and cancers."

The UNC School of Medicine laboratory of Camille Ehre, PhD, Assistant Professor of Pediatrics, produced striking images in respiratory tract cultures of the infectious form of the SARS-CoV-2 virus produced by infected respiratory epithelial cells. The New England Journal of Medicine featured this work in its "Images in Medicine" section.

Ehre, a member of the UNC Marsico Lung Institute and the UNC Children's Research Institute, captured these images to illustrate how intense the SARS-CoV-2 infection of the airways can be in very graphic and easily understood images. Her lab conducted this research in collaboration with the labs of Ralph Baric, PhD, the William R. Kenan Distinguished Professor of Epidemiology at the UNC Gillings School of Public Health, who holds a joint faculty appointment at the UNC Department of Microbiology and Immunology, and Richard Boucher, MD, the James C. Moeser Eminent Distinguished Professor of Medicine and Director of the Marsico Lung Institute at the UNC School of Medicine.

In a laboratory setting, the researchers inoculated the SARS-Co-V-2 virus into human bronchial epithelial cells, which were then examined 96 hours later using scanning electron microscopy.

The images, re-colorized by UNC medical student Cameron Morrison, show infected ciliated cells with strands of mucus (yellow) attached to cilia tips (blue). Cilia are the hair-like structures on the surface of airway epithelial cells that transport mucus (and trapped viruses) from the lung. A higher power magnification image shows the structure and density of SARS-CoV-2 virions (red) produced by human airway epithelia. Virions are the complete, infectious form of the virus released onto respiratory surfaces by infected host cells.

This imaging research helps illustrate the incredibly high number of virions produced and released per cell inside the human respiratory system. The large viral burden is a source for spread of infection to multiple organs of an infected individual and likely mediates the high frequency of COVID-19 transmission to others. These images make a strong case for the use of masks by infected and uninfected individuals to limit SARS-CoV-2 transmission.

Volcanoes are born and die - and then grow again on their own remains. The decay of a volcano in particular is often accompanied by catastrophic consequences, as was the most recent case for Anak Krakatau in 2018. The flank of the volcano had collapsed sliding into the sea. The resulting tsunami killed several hundred people on Indonesia's coast.

Continued volcanic activity after a collapse has not been documented in detail so far. Now and for the first time, researchers from the German Research Center for Geosciences GFZ and Russian volcanologists are presenting the results of a photogrammetric data series spanning seven decades for the Bezymianny volcano, Kamchatka, in the journal Nature Communications Earth and Environment. First author Alina Shevchenko from GFZ says, "thanks to the German-Russian cooperation we were able to analyze and reinterpret a unique data set".

Bezymianny had a collapse of its eastern sector in 1956. Photographs of helicopter overflights from Soviet times in combination with more recent satellite drone data have now been analyzed at GFZ Potsdam using state-of-the-art methods. The images show the rebirth of the volcano after its collapse. The initial re-growth began at different vents about 400 meters apart. After about two decades, the activity increased and the vents slowly moved together. After about fifty years, the activity concentrated on a single vent, which allowed the growth of a new and steep cone.

The authors of the study determined an average growth rate of 26,400 cubic meters per day - equivalent to about a thousand large dump trucks. The results make it possible to predict when the volcanic building may once again reach a critical height, so that it may collapse again under its own weight. The numerical modeling also explains the changes in stress within the volcanic rock and thus the migration of the eruption vents. Thomas Walter, volcanologist at the GFZ and co-author of the study, summarizes: "Our results show that the decay and re-growth of a volcano has a major impact on the pathways of the magma in the depth. Thus, disintegrated and newly grown volcanoes show a kind of memory of their altered field of stress". For future prognosis, this means that the history of birth and collapse must be included to be able to give estimates about possible eruptions or imminent collapses.

AURORA, Colo. (Sept. 9, 2020) - Researchers at the University of Colorado College of Nursing at the Anschutz Medical Campus found that a unique set of factors of the emergency department (ED) makes standard Clinical Decision Support (CDS) systems not as effective in helping to reduce antibiotic overprescribing in that environment.

Antimicrobial resistance is a major public health concern, accounting for 2.8 million infections and 35,000 deaths annually. Hospitals have focused on antibiotic stewardship programs (ASP) to reduce over prescribing of antibiotics, which is a major contributor to antimicrobial resistance. While this has been effective in reducing unnecessary antibiotic use by as much as 36% in inpatient settings, EDs are an exception where approximately 10 million outpatient antibiotic prescriptions are written annually in the US. Data show that up to 50% of the prescriptions were inappropriate or unnecessary.

The study, published in Applied Clinical Informatics, looked at three pediatric EDs to determine how the unique setting of the ED influences this pattern, and how Clinical Decision Support (CDS) systems can complement professional judgment in the ED setting and potentially reduce unnecessary antibiotic use. "The ED is unique. Several factors are at play - clinical judgment, provider fatigue, the busyness of the ED, workflow, technology, bed availability, social determinants of health of the patient and their families. said lead author Associate Professor Mustafa Ozkyanak, PhD. "These all impact antibiotic prescribing decisions."

The study of 38 ED providers analyzed these and additional factors to determine how to design a CDS system to assist with antimicrobial stewardship in pediatric emergency departments. It discovered that systems are rarely tailored to the context of the ED environment and end-user needs.

"ED clinicians often need to make rapid decisions and are frequently interrupted during the decision-making process," said Ozkaynak. Current CDS systems do not take this unique set of circumstances into account. "Significant opportunities exist to improve the appropriateness of antibiotic prescribing in the ED setting. Including relevant contextual data, considering the limitations of current CDS systems, and tailoring the design and implementation could all help in reducing unnecessary antibiotic use."

Tsukuba, Japan - It may sound like something out of a science fiction B-movie, but with the help of a mutant tomato, researchers from Japan have discovered that the development process of fruit rewires their central metabolism pathway.

In a study published this month in Proceedings of the National Academy of Sciences of the United States of America (PNAS), researchers from the University of Tsukuba have revealed that "fruit set"--the fruit development process in plants--rewired the central metabolism pathway in tomatoes via an increased sensitivity to the plant hormone gibberellin.

Tomatoes, although commonly thought of as vegetables, are actually fruit. Fruit set is the process whereby plant ovaries develop into fruits after pollination and fertilization, and in tomatoes the process is triggered by gibberellin. But the role of this hormone in the metabolic processes of fruit-setting ovaries is still mostly unknown.

"Pollination is usually key to bringing on fruit set, because it stimulates the buildup of plant growth hormones, including gibberellin, inside fertilized ovaries," says lead author of the study Professor Tohru Ariizumi. "Gibberellins stimulate aspects of plant development, such as fruit set, and trigger rapid ovary growth."

To examine fruit set in tomatoes, the researchers used multi-omics--specifically, looking at all the RNA, proteins, and small-molecule metabolites produced during metabolism--and enzyme activity data. Additionally, they used kinetic modelling to look at the earliest processes that occur during fruit set. Ovary growth during fruit set was measured using wild-type and procera mutant tomatoes, which are hypersensitive to gibberellin.

"Applying hormones like gibberellin to ovaries or genetic mutations in the negative regulatory genes of hormone cascades can bring on parthenocarpy," explains Professor Ariizumi. "Parthenocarpy is fruit set that is independent of pollination."

Gibberellins are signaling molecules that trigger signal transduction cascades--i.e., they activate or repress downstream genes that are responsible for carrying out particular developmental and growth processes.

"Our study looked at the biochemical mechanisms of fruit set. Our analysis was able to define the genes, proteins, enzymes and metabolites that were consistently affected by both pollination and procera-induced parthenocarpy, and highlighted that the central metabolism was consistently rewired," says Professor Ariizumi.

The results of this study contribute to a better understanding of fruit set metabolism, which will lead to new strategies for production. In particular, it may be possible to breed for parthenocarpic fruits (which are seedless), and to increase control of fruit survival during the early stages of development.

The article, "Fruit setting rewires central metabolism via gibberellin cascades," was published in Proceedings of the National Academy of Sciences of the United States of America (PNAS) at DOI: 10.1073/pnas.2011859117