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Piping plovers, charismatic shorebirds that nest and feed on many Atlantic Coast beaches, rely on different kinds of coastal habitats in different regions along the Atlantic Coast, according to a new study by the U.S. Geological Survey and U.S. Fish and Wildlife Service.

The Atlantic Coast and Northern Great Plains populations of the piping plover were listed as federally threatened in 1985. The Atlantic coast population is managed in three regional recovery units, or regions: New England, which includes Massachusetts and Rhode Island; Mid-Atlantic, which includes New York and New Jersey; and Southern, which includes Delaware, Maryland, Virginia, and North Carolina.

While the Atlantic populations are growing, piping plovers have not recovered as well in the Mid-Atlantic and Southern regions as they have in the New England region. The habitat differences uncovered by the study may be a factor in the unequal recovery.

"Knowing piping plovers are choosing different habitat for nesting up and down the Atlantic Coast is key information that resource managers can use to refine recovery plans and protect areas most needed for further recovery of the species," said Sara Zeigler, a USGS research geographer and the lead author of the study. "It will also help researchers predict how climate change impacts, such as increased storm frequency, erosion and sea-level rise, could affect habitat for this high-profile shorebird."

The researchers found that piping plovers breeding in the New England region were most likely to nest on the portion of the beach between the high-water line and the base of the dunes. By contrast, plovers in the Southern region nested farther inland in areas where storm waves have washed over and flattened the dunes - a process known as 'overwash.' In the Mid-Atlantic region plovers used both habitats but tended to select overwash areas more frequently.

In general, overwash areas tend to be less common than backshore -- shoreline to dunes -- habitats. Nesting pairs that rely on overwash features, such as those in the Mid-Atlantic and Southern regions, have more limited habitat compared to birds in New England that have adapted to nesting in backshore environments.

The authors suggest that the differences in nesting habitat selection may be related to the availability of quality food. Piping plover chicks, which cannot fly, must be able to access feeding areas on foot. In New England, piping plovers can find plenty of food along the ocean shoreline, so they may have more options for successful nesting. However, ocean shorelines along the Southern and Mid-Atlantic regions may not provide enough food, forcing adults and chicks to move towards bay shorelines on the interiors of barrier islands to feed. This would explain why so many nests in these regions occurred in overwash areas, which are scarcer than backshore areas but tend to provide a clear path to the bay shoreline.

In all three regions, plovers most often chose to nest in areas with sand mixed with shells and with sparse plant life. These materials match the species' sandy, mottled coloring and help the birds blend into the environment, enhancing the camouflage that is their natural defense against predators. Piping plover adults may avoid dense vegetation because it may impede their ability to watch for foxes, raccoons, coyotes and other predators.

The U.S. Atlantic Coast population of piping plovers increased from 476 breeding pairs when it was listed in 1985 to 1,818 pairs in 2019, according to the USFWS. The population increased by 830 breeding pairs in New England but only 349 and 163 pairs in the Mid-Atlantic and Southern regions respectively.

"This study will help us tailor coastal management recommendations in each region," said Anne Hecht, a USFWS endangered species biologist and a co-author of the paper. "We are grateful to the many partners who collected data for this study, which will help us be more effective in our efforts to recover the plover population."

"This research will fuel further studies on piping plovers, their habitat-use and food resources," Zeigler added. "Refining the models used in this research will help researchers predict habitat availability with future changes in shorelines, sea level and beach profiles."

WHAT:

The COVID-19 pandemic is affecting people with or at risk for HIV both indirectly, by interfering with HIV treatment and prevention services, and directly, by threatening individual health. An effective response to these dual pandemics requires unprecedented collaboration to accelerate basic and clinical research, as well as implementation science to expeditiously introduce evidence-based strategies into real-world settings. This message comes from a review article co-authored by Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and colleagues published in the Journal of Infectious Diseases.

By disrupting critical health care services, the COVID-19 pandemic threatens the substantial progress made in reducing the global burden of HIV. The authors note that the toll of COVID-19 on the HIV pandemic could be mitigated by increasing access to HIV treatment, for example, by prescribing multiple months of medication, and ensuring that HIV testing and prevention services are maintained.

Many questions remain as to whether people with HIV are more at risk for infection with SARS-CoV-2, the virus that causes COVID-19, and for developing severe COVID-19, as evidence to date is mixed. Rates of infection with SARS-CoV-2 are similar in people with and without HIV. However, populations that are disproportionately affected by HIV--including Black/African American and Hispanic/Latinx populations--also are at increased risk for acquiring SARS-CoV-2 infection and for developing severe COVID-19. Multiple factors contribute to the burden on these populations, including systemic health disparities, socio-economic inequalities and a higher prevalence of comorbidities.

While HIV infection itself does not appear to increase risk for severe COVID-19, mounting evidence indicates that specific comorbidities in people with HIV are linked to greater COVID-19 severity. Even when HIV is well-controlled with treatment, people with HIV bear a significant burden of numerous comorbidities, many of which have also emerged as risk factors for severe COVID-19. These comorbidities include certain cancers, chronic kidney disease, chronic obstructive pulmonary disease, cardiovascular disease, obesity and type 2 diabetes.

Accelerated development and clinical testing of prevention and treatment strategies are urgently needed to mitigate the juxtaposition of the HIV and COVID-19 pandemics, the authors conclude. This includes basic research on the interactions between HIV and SARS-CoV-2 at both the cellular and molecular levels, as well as clinical studies to evaluate outcomes for people with HIV and SARS-CoV-2 co-infections, including the impact of comorbidities.

April 8, 2021 - Routinely collected data on patients undergoing spinal fusion surgery do not provide a valid basis for assessing and comparing hospital performance on patient safety outcomes, reports a study in Spine. The journal is published in the Lippincott portfolio by Wolters Kluwer.

At a time when hospitals are increasingly subject to online rankings or "pay-for-performance" reimbursement programs, metrics based on hospital administrative data are "unreliable for profiling hospital performance," concludes the new research by Jacob K. Greenberg, MD, MSCI, of Washington University in St Louis and colleagues. They write, "These results provide important insights into the advisability of using administrative billing data to benchmark hospital quality in spine surgery."

Study finds unacceptably low hospital 'rankability' for spinal fusion

The researchers analyzed more than 367,000 spinal fusion surgery procedures performed in nine states between 2010 and 2017, drawn from nine state inpatient databases. Performed in patients with degenerative spine disease, spinal fusion is a common and costly inpatient surgical procedure. The study included data on approximately 154,000 procedures in the upper (cervical) spine and 213,000 in the lower (thoracic and lumbar) spine.

The analysis focused on serious complications such as return to the operating room, myocardial infarction (heart attack), death, or prolonged hospital stay. The study was designed to determine whether a metric based on publicly available information from state inpatient databases would be reliable for benchmarking and comparing performance between hospitals.

The researchers calculated a risk/reliability-adjusted complication rate to account for differences in the characteristics (case mix) of patients treated at each hospital. They then used a "rankability" measure to assess whether the metric could distinguish true differences in hospital performance from random fluctuations due to chance (signal-to-noise ratio).

Overall, 4.4 percent of patients undergoing cervical spinal fusion had serious complications. For this group of patients, rankability was consistently low - indicating that "rank-based profiling efforts would lead to widely varying results over time," Dr. Greenberg and colleagues write.

For patients undergoing thoracic and lumbar spinal fusion, the serious complication rate was 7.7 percent. Rankability was higher than for cervical spinal fusion. However, the metric's ability to compare complication rates between hospitals was still just slight to moderate depending on the year, indicating most differences across hospitals were due to chance.

The authors noted that rankability increases with the volume of spinal fusion procedures performed. However, only about one-third of hospitals performed sufficient numbers of thoracic-lumbar fusions to produce reliable estimates. Less than five percent performed enough cervical fusions for reliable rankings.

Medicare, Medicaid, and private insurers increasingly use complication rates or other safety metrics to adjust payments to doctors and hospitals for various conditions and procedures. Complication rates are not yet used in national benchmarking for spine surgery, but are widely used for hip and knee replacement surgery. "While payers are increasingly focused on implementing pay-for-performance measures, quality metrics must reliably reflect true differences in performance among the hospitals profiled," according to the authors.

The new analysis - including hundreds of thousands of procedures performed at hospitals across the United States - suggests that state inpatient data on complications are inappropriate for use in ranking and comparing hospital performance for spinal fusion procedures. Dr. Greenberg and colleagues conclude: "These results indicate that such metrics derived from administrative billing data should not be used in high-stakes applications, such as public reporting or pay-for-performance."

In a medical records study covering thousands of children, a U.S.-Canadian team led by researchers at Johns Hopkins Medicine concludes that while surgery to correct congenital heart disease (CHD) within 10 years after birth may restore young hearts to healthy function, it also may be associated with an increased risk of hypertension — high blood pressure — within a few months or years after surgery.

Waste materials from the pulp and paper industry have long been seen as possible fillers for building products like cement, but for years these materials have ended up in the landfill. Now, researchers at UBC Okanagan are developing guidelines to use this waste for road construction in an environmentally friendly manner.

The researchers were particularly interested in wood-based pulp mill fly ash (PFA), which is a non-hazardous commercial waste product. The North American pulp and paper industry generates more than one million tons of ash annually by burning wood in power boiler units for energy production. When sent to a landfill, the producer shoulders the cost of about $25 to $50 per ton, so mills are looking for alternative usages of these by-products.

"Anytime we can redirect waste to a sustainable alternative, we are heading in the right direction," says Dr. Sumi Siddiqua, associate professor at UBC Okanagan's School of Engineering. Dr. Siddiqua leads the Advanced Geomaterials Testing Lab, where researchers uncover different reuse options for industry byproducts.

This new research co-published with Postdoctoral Research Fellow Dr. Chinchu Cherian investigated using untreated PFA as an economically sustainable low-carbon binder for road construction.

"The porous nature of PFA acts like a gateway for the adhesiveness of the other materials in the cement that enables the overall structure to be stronger and more resilient than materials not made with PFA," says Dr. Cherian. "Through our material characterization and toxicology analysis, we found further environmental and societal benefits that producing this new material was more energy efficient and produced low-carbon emissions."

But Dr. Siddiqua notes the construction industry is concerned that toxins used in pulp and paper mills may leach out of the reused material.

"Our findings indicate because the cementation bonds developed through the use of the untreated PFA are so strong, little to no release of chemicals is apparent. Therefore, it can be considered as a safe raw material for environmental applications."

While Dr. Cherian explains that further research is required to establish guidelines for PFA modifications to ensure its consistency, she is confident their research is on the right track.

"Overall, our research affirms the use of recycled wood ash from pulp mills for construction activities such as making sustainable roads and cost-neutral buildings can derive enormous environmental and economic benefits," she says. "And not just benefits for the industry, but to society as a whole by reducing waste going to landfills and reducing our ecological footprints."

In the meantime, while cement producers can start incorporating PFA into their products, Dr. Cherian says they should be continually testing and evaluating the PFA properties to ensure overall quality.

EVANSTON, Ill. -- Five-star ratings are no guarantee to lead you to the perfect barber who truly understands your hair or to the espresso machine that brews a perfect cup of coffee.

That's because most products online are now rated positively, making it harder than ever to truly discern whether they will succeed in the marketplace.

A new study from Northwestern University Kellogg School of Management and the University of Massachusetts Boston was able to predict the success of movies, commercials, books and restaurants by relying on the "emotionality" of reviews instead of the star rating.

The researchers explored box office revenue of 2,400 movies, sales of 1.6 million books and real-world reservations at more than 1,000 restaurants. In their analysis, emotion reigned supreme; in fact, higher star ratings were either a weaker signal of success or negatively related to success.

"One attractive aspect of online purchasing is that consumers have reviews at their fingertips," said Derek D. Rucker, the Sandy & Morton Goldman Professor of Entrepreneurial Studies in Marketing at Kellogg and co-author of the study.

"However, this research demonstrates a 'positivity problem': Most reviews are positive. In this 'sea of positivity,' how do people distinguish products?" Rucker said.

On Amazon.com, for example, the average star rating is approximately 4.2 out of 5 with well over half of the reviews being five-star ratings. Nearly half of all Yelp reviews are five-star ratings, and recent research indicates that nearly 90% of Uber ratings may be five stars.

Indeed, the study found that review ratings were overwhelmingly four and five stars, a few one-star ratings, and few ratings in between.

Clues to success, it turns out, may rest in the very language consumers use.

Across four large-scale studies, the researchers used computational linguistics to assess the emotionality of reviews -- that is whether the reviews suggested the person writing it had an emotional reaction to the product.

In one study, they looked at the movie industry and examined 13 years of Metacritic reviews from 2005 to 2018. Star ratings, they found, were a significant negative predictor of box office success. Emotionality, however, was a significant positive predictor.

The researchers also were able to predict the success of books on Amazon using the same model based on 20 years of data from 1995 to 2015. They found that 91% of books received a positive rating (four or five stars). The average star rating was an unreliable and sometimes even negative predictor of purchases; however, greater emotionality was predictive of more sales in 93% of genres.

They also examined television commercials. For both the 2016 and 2017 Super Bowls, they obtained real-time tweets the day those ads aired and they measured the subsequent gain in Facebook followers. Then, they compared their own model, which incorporates text emotionality, to the USA Today Ad Meter survey, a popular Super Bowl rating system. The USA Today rating was not predictive of the number of new followers. But the greater the emotionality of tweets, the more Facebook followers a company gained over the following two weeks.

Another domain they turned their attention to was restaurants. Relying on Yelp reviews, the researchers examined whether star ratings or emotionality was a better predictor of table reservations.

Although the average star rating did predict more table reservations, the emotional analysis of restaurant reviews eclipsed the predictive ability of star ratings.

A positive and highly emotional review might read: "I love this restaurant, it is absolutely wonderful." In contrast, a position, but less emotional review might read: "This restaurant is excellent, dinner was flawless."

"This research shows just how pervasive the positivity problem is in online reviews. This work also advances our understanding of emotionality -- a construct considered of significant importance across the social sciences -- by revealing it can predict behavior and marketplace success," explained lead author Matt Rocklage, assistant professor of marketing at University of Massachusetts Boston.

"This work could also lay the foundation for alternatives to star ratings. Firms might ask for a future 'emotional star rating' to understand the attention to the emotionality of individuals' attitudes," said Loran Nordgren, professor of management and organizations at Kellogg and co-author of the paper.

Astronomers at Western University have discovered the most rapidly rotating brown dwarfs known. They found three brown dwarfs that each complete a full rotation roughly once every hour. That rate is so extreme that if these "failed stars" rotated any faster, they could come close to tearing themselves apart. Identified by NASA's Spitzer Space Telescope, the brown dwarfs were then studied by ground-based telescopes including Gemini North, which confirmed their surprisingly speedy rotation.

Three brown dwarfs have been discovered spinning faster than any other found before. Astronomers at Western University in Canada first measured the rotation speeds of these brown dwarfs using NASA's Spitzer Space Telescope and confirmed them with follow-up observations with the Gemini North telescope on Maunakea in Hawai'i and the Carnegie Institution for Science's Magellan Baade telescope in Chile. Gemini North is one of the pair of telescopes that make up the international Gemini Observatory, a Program of NSF's NOIRLab.

"We seem to have come across a speed limit on the rotation of brown dwarfs," said Megan Tannock, the Western University physics and astronomy graduate student who led the discovery. "Despite extensive searches, by our own team and others, no brown dwarfs have been found to rotate any faster. In fact, faster spins may lead to a brown dwarf tearing itself apart."

Brown dwarfs are, simply put, failed stars. They form like stars but are less massive and more like giant planets [1].

Tannock and Western University astronomer Stanimir Metchev worked with international collaborators to find three rapidly rotating brown dwarfs spinning around their axes once every hour. This is approximately 10 times faster than normal [2], and about 30 percent faster than the most rapid rotations previously measured in such objects.

The astronomers used large ground-based telescopes, Gemini North in Hawai'i and Magellan Baade in Chile, to confirm the rapid rotations. They did this by measuring alterations in the brown dwarfs' light caused by the Doppler effect and using a computer model to match those alterations to spin rates [3]. The researchers found that these brown dwarfs spin with speeds of about 350,000 kilometers per hour (around 220,000 miles per hour) at their equator, which is 10 times faster than Jupiter.

"These unusual brown dwarfs are spinning at dizzying speeds," said Sandy Leggett, an astronomer at Gemini North who studies brown dwarfs. "At about 350,000 kilometers per hour, the relatively weak gravity of the brown dwarfs is barely holding them together. This exciting discovery by the Tannock team has identified rotational limits beyond which these objects may not exist."

The team first identified the rapid rotation rates by using NASA's Spitzer Space Telescope to measure how quickly the brightness of the objects varied. "Brown dwarfs, like planets with atmospheres, can have large weather storms that affect their visible brightness," explained Metchev. "The observed brightness variations show how frequently the same storms are seen as the object spins, which reveals the brown dwarf's spin period."

The team's results will appear in an upcoming issue of The Astronomical Journal.

A global science collaboration using data from NASA's Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station has discovered X-ray surges accompanying radio bursts from the pulsar in the Crab Nebula. The finding shows that these bursts, called giant radio pulses, release far more energy than previously suspected.

A pulsar is a type of rapidly spinning neutron star, the crushed, city-sized core of a star that exploded as a supernova. A young, isolated neutron star can spin dozens of times each second, and its whirling magnetic field powers beams of radio waves, visible light, X-rays, and gamma rays. If these beams sweep past Earth, astronomers observe clock-like pulses of emission and classify the object as a pulsar.

"Out of more than 2,800 pulsars cataloged, the Crab pulsar is one of only a few that emit giant radio pulses, which occur sporadically and can be hundreds to thousands of times brighter than the regular pulses," said lead scientist Teruaki Enoto at the RIKEN Cluster for Pioneering Research in Wako, Saitama prefecture, Japan. "After decades of observations, only the Crab has been shown to enhance its giant radio pulses with emission from other parts of the spectrum."

The new study, which will appear in the April 9 edition of Science and is now available online, analyzed the largest amount of simultaneous X-ray and radio data ever collected from a pulsar. It extends the observed energy range associated with this enhancement phenomenon by thousands of times.

Located about 6,500 light-years away in the constellation Taurus, the Crab Nebula and its pulsar formed in a supernova whose light reached Earth in July 1054. The neutron star spins 30 times each second, and at X-ray and radio wavelengths it is among the brightest pulsars in the sky.

Between August 2017 and August 2019, Enoto and his colleagues used NICER to repeatedly observe the Crab pulsar in X-rays with energies up to 10,000 electron volts, or thousands of times that of visible light. While NICER was watching, the team also studied the object using at least one of two ground-based radio telescopes in Japan - the 34-meter dish at the Kashima Space Technology Center and the 64-meter dish at the Japan Aerospace Exploration Agency's Usuda Deep Space Center, both operating at a frequency of 2 gigahertz.

he combined dataset effectively gave the researchers nearly a day and a half of simultaneous X-ray and radio coverage. All told, they captured activity across 3.7 million pulsar rotations and netted some 26,000 giant radio pulses.

Giant pulses erupt quickly, spiking in millionths of a second, and occur unpredictably. However, when they occur, they coincide with the regular clockwork pulsations.

NICER records the arrival time of every X-ray it detects to within 100 nanoseconds, but the telescope's timing precision isn't its only advantage for this study.

"NICER's capacity for observing bright X-ray sources is nearly four times greater than the combined brightness of both the pulsar and its nebula," said Zaven Arzoumanian, the project's science lead at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "So these observations were largely unaffected by pileup - where a detector counts two or more X-rays as a single event - and other issues that have complicated earlier analyses."

Enoto's team combined all of the X-ray data that coincided with giant radio pulses, revealing an X-ray boost of about 4% that occurred in synch with them. It's remarkably similar to the 3% rise in visible light also associated with the phenomenon, discovered in 2003. Compared to the brightness difference between the Crab's regular and giant pulses, these changes are remarkably small and provide a challenge for theoretical models to explain.

The enhancements suggest that giant pulses are a manifestation of underlying processes that produce emission spanning the electromagnetic spectrum, from radio to X-rays. And because X-rays pack millions of times the punch of radio waves, even a modest increase represents a large energy contribution. The researchers conclude that the total emitted energy associated with a giant pulse is dozens to hundreds of times higher than previously estimated from the radio and optical data alone.

"We still don't understand how or where pulsars produce their complex and wide-ranging emission, and it's gratifying to have contributed another piece to the multiwavelength puzzle of these fascinating objects," Enoto said.

SALT LAKE CITY - A letter published today by Huntsman Cancer Institute (HCI) at the University of Utah (U of U) in the New England Journal of Medicine reports that melanoma mortality among Utahns outpaced that of the rest of the United States during the period from 1975 to 2013. Melanoma death rates have been decreasing in recent years both in Utah and the United States, a trend likely attributable to new, more effective treatments, like immunotherapy. However, melanoma remains the deadliest type of skin cancer, and the incidence of melanoma diagnoses in Utahns is higher than in any other state.

The research was conducted in response to recent published data showing that for most of the 1990s and 2000s, melanoma mortality in the United States remained constant, while incidence increased six-fold. Increasing incidence without a corresponding increase in mortality suggests a potentially worrying trend of overdiagnosis--that is, when patients with benign conditions are incorrectly diagnosed as having cancer. In the case of melanoma, overdiagnosis may result from increased scrutiny, where repeated skin exams lead to increasing numbers of biopsies and a higher chance of finding a lesion that would not have been detected otherwise, and which might not be likely to progress to a harmful cancer.

Given Utah's status as the state with the highest incidence of melanoma, the HCI team set out to evaluate the melanoma diagnosis and death rate data in Utah. After review and analysis of data by biostatistician Kim Herget from the Utah Cancer Registry, a National Cancer Institute Survival, Epidemiology, and End Results (SEER) database, the researchers found that in contrast to the rest of the United States, melanoma mortality in Utah increased by 0.8% per year through the entire period from 1975 through 2013. While melanoma deaths in Utah are decreasing in recent years, Utah's melanoma death rate remains higher than that observed in the rest of the United States.

"Although we agree that overdiagnosis of melanoma is a growing problem, the sustained increase in melanoma mortality in Utah suggests that at least some fraction of the increasing incidence is real and cannot be attributed solely to overdiagnosis," said Doug Grossman, MD, PhD, who co-leads the HCI melanoma and skin cancer center at HCI and serves as professor of dermatology at the U of U. "Our research underscores an increased risk for Utahns, and so we must remain vigilant about melanoma. For doctors, this means regular conversations with patients about their skin health and family history. For patients, this means practicing sun-safe behaviors like diligent sunscreen use, wearing sun-protective clothing, and monitoring their skin at home on a monthly basis to reduce risk of skin cancer and optimize early detection."

The researchers anticipate future studies to determine whether this trend in Utahns is a result of increased ultraviolet exposure in a largely fair-skinned population living in a sunny, high-altitude climate or is associated with other environmental or genetic factors.

LOS ALAMOS, N.M., April 8, 2021-While attention has been focused on the Perseverance rover that landed on Mars last month, its predecessor Curiosity continues to explore the base of Mount Sharp on the red planet and is still making discoveries. Research published today in the journal Geology shows that Mars had drier and wetter eras before drying up completely about 3 billion years ago.

"A primary goal of the Curiosity mission was to study the transition between the habitable environment of the past, to the dry and cold climate that Mars has now. These rock layers recorded that change in great detail," said Roger Wiens, a coauthor on the paper and scientist at Los Alamos National Laboratory, where he is on the ChemCam team. ChemCam is the rock-vaporizing laser that sits on the mast of the Curiosity rover and analyzes the chemical composition of martian rocks.

William Rapin, a researcher with the French National Centre for Scientific Research (CNRS), led the study

Using the long-range camera on ChemCam to make detailed observations of the steep terrain of Mount Sharp, a team including Wiens and other researchers at Los Alamos discovered that the Martian climate alternated between dry and wetter periods before it went completely dry. Spacecraft in orbit around Mars had previously provided clues about the mineral composition of the slopes of Mount Sharp. Now, ChemCam has successfully made detailed observations of the sedimentary beds from the planet's surface, revealing the conditions under which they formed.

Moving up through the terrain, Curiosity observed that the types of bed change drastically. Lying above the lake-deposited clays that form the base of Mount Sharp, sandstone layers show structures indicating their formation from wind-formed dunes, suggesting long, dry climate episodes. Higher up still, thin alternating brittle and resistant beds are typical of river floodplain deposits, marking the return of wetter conditions.

These changes in terrain show that the climate of Mars underwent several large-scale fluctuations between wetter and dryer periods, until the generally arid conditions observed today took hold. During its extended mission, Curiosity is scheduled to climb the foothills of Mount Sharp and drill into its various beds for a closer look at these fascinating materials.

The ChemCam laser instrument uses an infrared-colored laser beam, which heats rock fragments to around 18,000 degrees Fahrenheit (10,000 degrees Celsius), vaporizing them. The plasma produced by this process allows scientists to analyze the chemical and mineral composition of the rocks, which convey important information about the geological history of Mars. The instrument also has a high-resolution camera. ChemCam is commanded alternately from Los Alamos in New Mexico and the French Space Agency in Toulouse, as a partnership between Los Alamos National Laboratory and the IRAP research center. Every week, the operations change hands between the two places. Together, the ChemCam team has published over 100 scientific papers on its discoveries from more than 850,000 laser zaps.

PHILADELPHIA (April 8, 2021) - Many factors, including need, affect healthcare use. Strategies geared to enhancing the provision and access to healthcare must consider the various mechanisms that contribute to healthcare need and use. Until now, the mechanism of violence and its impact on both health and healthcare use has not been investigated.

A new study from the University of Pennsylvania School of Nursing (Penn Nursing) is one of the first to examine the association between violence exposure and healthcare service utilization in Mexico. Results are published in the International Journal of Health Equity.

Widespread violence in Mexico can impact health through various channels. The study explores how violence relates to service utilization changes as a possible mechanism that may impact short- and long-term health. "Violence is a pervasive problem in developing nations such as Mexico and its consequences for service utilization are important to understand," says Laura X. Vargas, PhD, MSW, MPA, Vice-Provost post-doctoral fellow at the Penn Injury Science Center at Penn Nursing and lead author of the study.

Given the prolonged period of escalating violence in Mexico, policymakers should consider whether broader investments in health prevention, primary care, and mental health might effectively buffer some of the long-term (perhaps costlier) impacts of violence on the health of society, the researchers suggest. "One way to do that, for example, is by making trauma-informed health services widely available at the primary care level to improve health outcomes in communities exposed to violence," says Therese S. Richmond, PhD, RN, FAAN, Andrea B. Laporte Professor of Nursing and Associate Dean for Research & Innovation at Penn Nursing, one of the co-authors of the article.

Ion channels play an indispensable role in cellular physiology, and understanding the physical features that affect ion channel functions is a matter of considerable interest to biologists. Given that mechanosensitivity is an intrinsic feature of cells, the complex set of mechanical stresses acting on a cell at any time represents an important consideration in the field of cellular physiology. In fact, stretching forces created by mechanical stress are sometimes necessary to activate ion channels. As Professor Masayuki Iwamoto and Professor Shigetoshi Oiki of the University of Fukui explain, "Mechanical stresses change the level of cell membrane tension, and stretch-activated ion channels in the membrane mediate tension-related electrical transduction".

Recent experiments have shown that tension sensitivity is a property of ion channels other than those historically classified as "mechanosensitive" channels, and biophysicists are coming to see tension sensitivity as an intrinsic property of ion channels in general. However, efforts to elucidate the physiological relevance and molecular mechanisms of such tension sensitivity depend on the establishment of experimental methods that allow experimenters to evaluate dynamic changes in membrane tension in real time.

To meet this growing need, Professors Iwamoto and Oiki focused their efforts on developing a novel time-lapse system for measuring membrane tension. In their experiments, they formed a bilayer by docking two monolayer-lined water bubbles and evaluated tension using the Young-Laplace principle to measure intra-bubble pressures lower than 100 pascals. This novel experimental method has the advantage of relying on a straightforward model system consisting of purified channels and a simple lipid bilayer. This model allows experimenters to avoid the unmanageable complexity of real cell membranes, which feature a wide variety of ion channels and accessory proteins. The experimental setup permits real-time monitoring of membrane tension.

The KcsA ion channel is the prototypical ion channel used to understand ion channel structure-function relationships. The channel functions in the bilayer, and this is an important advantage given the rapid variability in membrane tension that occurs during actual cellular activity while recording the dynamic responsiveness of the KcsA ion channel. These experiments revealed a novel mode of action for tension sensitivity without precedent in the existing literature. Their results appear in a paper recently published in the peer-reviewed journal JACS Au.

Interestingly, the KcsA ion channels exhibited sensitivity to membrane tension and responded quickly to its fluctuations. One notable observation was that the ion channels' responses to increasing membrane tension differed substantially from their responses to decreasing membrane tension. During the stretching phase, the channels started to activate only when the membrane tension reached high levels. In the tension decreasing phase, they remained active for a while even after returning to a low level of tension. This feature is called hysteresis, and it implies that the channel molecules can "memorize" their active state for a short period.

In conclusion, Professors Iwamoto and Oiki have developed a time-lapse system for measuring membrane tension while recording the dynamic responsiveness of a prototypical ion channel. Their findings revealed a process of hysteresis, which they note "extends existing knowledge of the mechanisms of the tension-sensitive channels that play key roles in various cellular activities."

The present study is thus important both as a demonstration of a new method for fundamental ion channel research and as basic research into ion channel mechanisms. The insights into hysteresis as a functional feature of KcsA ion channels could be valuable for drug discovery research.

BIRMINGHAM, Ala. - Six years ago, Michael Niederweis, Ph.D., described the first toxin ever found for the deadly pathogen Mycobacterium tuberculosis. This toxin, tuberculosis necrotizing toxin, or TNT, became the founding member of a novel class of previously unrecognized toxins present in more than 600 bacterial and fungal species, as determined by protein sequence similarity. The toxin is released as M. tuberculosis bacteria survive and grow inside their human macrophage host, killing the macrophage and allowing the escape and spread of the bacteria.

For 132 years, the lack of an identified toxin in M. tuberculosis had contrasted with nearly all other pathogenic bacteria whose toxins contribute to illness or death. M. tuberculosis infects 9 million people a year and kills more than 1 million.

Now, in another groundbreaking work, the University of Alabama at Birmingham researcher and colleagues describe how two small ESX proteins made by the M. tuberculosis bacteria mediate secretion of TNT by pore formation in the membranes that envelop the bacteria. This finding may have broad application because a distinctive three-amino acid motif found on EsxE and EsxF -- tryptophan/any-amino-acid/glycine, known in shorthand as WXG -- is also found on many other small mycobacterium proteins and on the large WXG100 superfamily of bacterial proteins that resemble EsxE and EsxF.

"Here, we show for the first time that small Esx proteins of the WXG100 family have an important molecular function inside the Mtb cell by mediating toxin secretion," said Niederweis, a professor in the UAB Department of Microbiology. "Our results suggest a dynamic mechanism of pore formation by small Esx proteins that might be applicable to other members of the large WXG100 protein family. Thus, our study not only represents a major advancement in our understanding of secretion of TNT and likely of other proteins in M. tuberculosis, but also describes a biological function for Esx-paralogs in M. tuberculosis and their homologs in the large WXG100 protein family in Gram-positive bacteria."

TNT is one of two domains in the M. tuberculosis outer membrane protein CpnT; activity of the TNT domain of CpnT in the cytosol of the macrophage induces macrophage death by hydrolyzing NAD+. M. tuberculosis has an inner membrane and an outer membrane, and a protein needs to get through each layer to be secreted outside of the bacterium. How CpnT gets to the outer membrane was unknown.

EsxE and EsxF are part of the same gene segment as CpnT, and the UAB researchers hypothesized that the two small proteins might be involved in secretion of the toxin.

By creating different strains that lacked either EsxE or EsxF, they showed that both proteins were necessary for the translocation of CpnT to the cell surface of M. tuberculosis and for the secretion of TNT into the cytosol of macrophages infected with M. tuberculosis. Furthermore, EsxE and EsxF are surface-accessible proteins on M. tuberculosis as a membrane-associated complex.

To learn more about the mechanism of that translocation, the UAB team made mutants of each Esx protein, where the tryptophan amino acid of the single WXG motif on each protein was replaced by the amino acid alanine. The mutants showed that an intact WXG motif on EsxE and on EsxF were required for efficient CpnT translocation to the outer membrane of M. tuberculosis and subsequent TNT secretion into the cytosol of infected macrophages.

Purification of the water-soluble EsxE and EsxF proteins showed they formed EsxE-EsxF dimers, and five of these dimers assembled into star-shaped structures, as viewed by electron microscopy. Each was about 10 nanometers across, with a 3-nanometer central pore.

Experiments with planar lipid bilayers were key to understanding the molecular function of EsxE-EsxF, as they showed that the EsxE-EsxF pores formed channels through lipid membranes.

Finally, the researchers showed that the WXG motifs were required for pore formation and membrane disruption by the EsxE-EsxF complex, and the motifs mediated assembly of functional EsxE-EsxF oligomers. This now defines a biochemical role for the previously enigmatic WXG motif.

"EsxE and EsxF constitute the first known outer membrane components mediating protein secretion in M. tuberculosis," Niederweis said. "However, it is unlikely that EsxE and EsxF are sufficient for TNT secretion, since an energy source is required in all known bacterial protein secretion systems. Therefore, it is possible that EsxE-EsxF associate with other proteins or protein complexes to achieve CpnT export and TNT secretion."

The UAB researchers propose two models for the transport of CpnT by EsxE and EsxF. In the first, the EsxE-EsxF heterodimers form a pore in the inner membrane, and then form another pore in the outer membrane to create transmembrane channels. "Alternatively," Niederweis said, "the inner membrane channel is extended to span the periplasm via filament formation, and connects to EsxE-EsxF pores in the outer membrane, exposing EsxF on the cell surface. In this model, the putative EsxE-EsxF channel tunnel enables export of the CpnT polypeptide to the outer membrane of M. tuberculosis, and subsequent secretion of TNT and EsxE-EsxF."

Co-authors with Niederweis in the study, "Pore-forming Esx proteins mediate toxin secretion
by Mycobacterium tuberculosis," published in Nature Communications, are Uday Tak and Terje Dokland, UAB Department of Microbiology.

"This work was a remarkable achievement of an outstanding graduate student, Uday Tak, who did almost all of these experiments by himself," Niederweis said. Uday Tak obtained his Ph.D. in November 2020 and is now a postdoctoral fellow at the University of Colorado-Boulder.

With the help of machine-learning techniques, a team of astronomers has discovered a dozen quasars that have been warped by a naturally occurring cosmic "lens" and split into four similar images. Quasars are extremely luminous cores of distant galaxies that are powered by supermassive black holes.

Over the past four decades, astronomers had found about 50 of these "quadruply imaged quasars," or quads for short, which occur when the gravity of a massive galaxy that happens to sit in front of a quasar splits its single image into four. The latest study, which spanned only a year and a half, increases the number of known quads by about 25 percent and demonstrates the power of machine learning to assist astronomers in their search for these cosmic oddities.

"The quads are gold mines for all sorts of questions. They can help determine the expansion rate of the universe, and help address other mysteries, such as dark matter and quasar 'central engines,'" says Daniel Stern, lead author of the new study and a research scientist at the Jet Propulsion Laboratory, which is managed by Caltech for NASA. "They are not just needles in a haystack but Swiss Army knives because they have so many uses."

The findings, to be published in The Astrophysical Journal, were made by combining machine-learning tools with data from several ground- and space-based telescopes, including the European Space Agency's Gaia mission; NASA's Wide-field Infrared Survey Explorer (or WISE); the W. M. Keck Observatory on Maunakea, Hawaii; Caltech's Palomar Observatory; the European Southern Observatory's New Technology Telescope in Chile; and the Gemini South telescope in Chile.

Cosmological Dilemma

In recent years, a discrepancy has emerged over the precise value of the universe's expansion rate, also known as Hubble's constant. Two primary means can be used to determine this number: one relies on measurements of the distance and speed of objects in our local universe, and the other extrapolates the rate from models based on distant radiation left over from the birth of our universe, called the cosmic microwave background. The problem is that the numbers do not match.

"There are potentially systematic errors in the measurements, but that is looking less and less likely," says Stern. "More enticingly, the discrepancy in the values could mean that something about our model of the universe is wrong and there is new physics to discover."

The new quasar quads, which the team gave nicknames such as Wolf's Paw and Dragon Kite, will help in future calculations of Hubble's constant and may illuminate why the two primary measurements are not in alignment. The quasars lie in between the local and distant targets used for the previous calculations, so they give astronomers a way to probe the intermediate range of the universe. A quasar-based determination of Hubble's constant could indicate which of the two values is correct, or, perhaps more interestingly, could show that the constant lies somewhere between the locally determined and distant value, a possible sign of previously unknown physics.

Gravitational Illusions

The multiplication of quasar images and other objects in the cosmos occurs when the gravity of a foreground object, such as a galaxy, bends and magnifies the light of objects behind it. The phenomenon, called gravitational lensing, has been seen many times before. Sometimes quasars are lensed into two similar images; less commonly, they are lensed into four.

"Quads are better than the doubly imaged quasars for cosmology studies, such as measuring the distance to objects, because they can be exquisitely well modeled," says co-author George Djorgovski, professor of astronomy and data science at Caltech. "They are relatively clean laboratories for making these cosmological measurements."

In the new study, the researchers used data from WISE, which has relatively coarse resolution, to find likely quasars, and then used the sharp resolution of Gaia to identify which of the WISE quasars were associated with possible quadruply imaged quasars. The researchers then applied machine-learning tools to pick out which candidates were most likely multiply imaged sources and not just different stars sitting close to each other in the sky. Follow-up observations by Keck, Palomar, the New Technology Telescope, and Gemini-South confirmed which of the objects were indeed quadruply imaged quasars lying billions of light-years away.

Humans and Machines Working Together

The first quad found with the help of machine learning, nicknamed Centaurus' Victory, was confirmed during an all-nighter the team spent at Caltech, with collaborators from Belgium, France, and Germany, while using a dedicated computer in Brazil, recalls co-author Alberto Krone-Martins of UC Irvine. The team had been remotely observing their objects using the Keck Observatory.

"Machine learning was key to our study but it is not meant to replace human decisions," explains Krone-Martins. "We continuously train and update the models in an ongoing learning loop, such that humans and the human expertise are an essential part of the loop. When we talk about 'AI' in reference to machine-learning tools like these, it stands for Augmented Intelligence not Artificial Intelligence."

"Alberto not only initially came up with the clever machine-learning algorithms for this project, but it was his idea to use the Gaia data, something that had not been done before for this type of project," says Djorgovski.

"This story is not just about finding interesting gravitational lenses," he says, "but also about how a combination of big data and machine learning can lead to new discoveries."

Cells from healthy individuals with major depressive disorder were found to have higher than expected rates of methylation at specific sites on their DNA, when compared to cells from healthy individuals without MDD, according to a study by a multidisciplinary team of Walter Reed Army Institute of Research and University of California San Francisco scientists, in collaboration with others.

Methylation is a process by which DNA is chemically modified at specific sites, resulting in changes in the expression of certain genes. Methylation of particular sets of genes, called "DNA methylation clocks," typically change in predictable ways as people age, but the rate of these changes varies between people. Methylation patterns in individuals with MDD suggested that their DNA methylation cellular age was, on average, accelerated relative to matched healthy controls.

In the study, published in Translational Psychiatry, blood samples from 49 individuals with MDD were compared to 60 healthy control subjects of the same chronological age using the 'GrimAge' clock--a mathematical algorithm designed to predict an individual's remaining lifespan based on cellular methylation patterns. Individuals with MDD showed a significantly higher GrimAge score, suggesting increased mortality risk compared to healthy individuals of the same chronological age--an average of approximately two years on the GrimAge clock.

The individuals with MDD were unmedicated prior to the study and showed no outward signs of age-related pathology, as they and the healthy controls were screened for physical health before entry into the study. The methylation patterns associated with mortality risk persisted even after accounting for lifestyle factors like smoking and BMI. These findings provide new insight into the increased mortality and morbidity associated with the condition, suggesting that there is an underlying biological mechanism accelerating cellular aging in some MDD sufferers.

"This is shifting the way we understand depression, from a purely mental or psychiatric disease, limited to processes in the brain, to a whole-body disease," said Katerina Protsenko, a medical student at UCSF and lead author of the study. "This should fundamentally alter the way we approach depression and how we think about it--as a part of overall health."

MDD is one of the most prevalent health concerns globally. According to the World health Organization, some 300 million people (4.4% of the population) suffer from some form of depression. MDD is associated with higher incidence and mortality related to increased rates of cardiovascular disease, diabetes, and Alzheimer's disease among sufferers.

"One of the things that's remarkable about depression is that sufferers have unexpectedly higher rates of age-related physical illnesses and early mortality, even after accounting for things like suicide and lifestyle habits," said Dr. Owen Wolkowitz, professor of psychiatry and a member of UCSF's Weill Institute for Neurosciences, co-senior author of the study. "That's always been a mystery, and that's what led us to look for signs of aging at the cellular level."

The researchers say that they don't yet know if depression causes altered methylation in certain individuals, or if depression and methylation are both related to another underlying factor. It is possible that some individuals may have a genetic predisposition to produce specific methylation patterns in response to stressors, but this has not been well-studied. Alterations in methylation patterns have previously been observed in individuals with post-traumatic stress disorder.

"These findings will allow us to better understand the relationships between behavioral health disorders--for example, 60% of PTSD cases are co-morbid with MDD. Elucidating these mechanistic and biochemical underpinnings will improve efforts to develop targeted diagnostic and treatment strategies, ultimately improving patient care," said Dr. Marti Jett, WRAIR chief scientist. Previous research from the group used GrimAge to study men with combat PTSD.

Moving forward, the researchers hope to determine whether pharmacological treatments or therapy may mitigate some methylation changes related to MDD in hopes of normalizing the cellular aging process in affected individuals before it advances. Also, although the "GrimAge" methylation clock has been associated with mortality in other populations, no studies have yet prospectively determined whether this methylation pattern also predicts mortality in MDD.

"As we continue our studies, we hope to find out whether addressing the MDD with anti-depressants or other treatments alters the methylation patterns, which would give us some indication that these patterns are dynamic and can be changed," said Dr. Synthia Mellon, professor in the Department of Obstetrics, Gynecology and the Reproductive Sciences at UCSF and co-senior author of the study.