Culture

CHAPEL HILL, NC - Aug. 11, 2020 - This spring, due to limited national supplies of N95 face masks, hospitals across the country asked the public and private companies to donate personal protective equipment (PPE), including many different types of masks, to be sure healthcare workers were protected while caring for patients.

With so many options, infection prevention experts at the UNC Medical Center set out to gather evidence on the fitted filtration efficiency of dozens of different types of masks and mask modifications, including masks sterilized for reuse, expired masks, novel masks sourced from domestic and overseas sources, and homemade masks.

Their data, published today in JAMA Internal Medicine, show that reused, sterilized N95 masks and very out-of-date N95 masks retain their effectiveness at protecting healthcare workers from COVID-19 infection.

To assess mask fitted filtration effectiveness, Emily Sickbert-Bennett, PhD, director of Infection Prevention at UNC Medical Center and colleagues turned to someone she knew she could trust: her dad, William Bennett, PhD, professor of medicine, who leads the Mucociliary Clearance and Aerosol Research Laboratory at the UNC Center for Environmental Medicine, Asthma, and Lung Biology (CEMALB).

"I told him we had two types of masks - used, sterilized and expired N95 masks - and we needed to know whether they would offer safe and effective protection, in case we needed our healthcare co-workers to use them." Sickbert-Bennett said. "And he said it would be possible for his lab to test them and give us data upon which to base our decision-making."

Thanks to a cooperative agreement with the EPA Human Studies Facility on the UNC-Chapel Hill campus, in which Bennett's labs reside, Bennett, assistant professor Phillip Clapp, PhD, and research associate Kirby Zeman, PhD, teamed with EPA research scientist, James Samet, PhD, to measure the fraction of submicron particles that penetrate into the breathing space of subjects wearing a mask while performing a series of tasks that simulate conditions such as speech and movement during a work shift. Such tests provided infection prevention leaders quantitative data they used to rank the best respiratory protection options for healthcare personnel during the COVID-19 outbreak.

The researchers found that certain N95 masks - as rated by the National Institute of Occupational Safety and Health (NIOSH) Administration - provide greater than 95 percent effectiveness at keeping the wearer from inhaling very small airborne particles that may carry SARS-CoV-2 - the virus that can cause COVID-19. Furthermore, these masks retain such effectiveness many years beyond the masks' expiration dates. In addition, these NIOSH-rated masks can be subjected to sterilization with hydrogen peroxide or ethylene oxide without compromising their efficiency. Finally, their fitted filtration procedures showed that surgical masks with ties were approximately 70 percent effective at filtering their inhaled particles, while surgical masks with ear loops were about 40 percent effective. Clapp, co-first author, emphasized that, "One of the keys to protection is how snug a mask fits. An N95 mask that forms a tight seal offers the optimal infection prevention. However, evidence from previous studies suggests that even the surgical masks with

"Our hierarchy of mask supplies essentially amounts to always using the safest option on the shelf, especially for those healthcare workers caring for COVID-19 patients," said Sickbert-Bennett, co-first author of the JAMA Internal Medicine paper. "We start with products of our usual make and model, then follow with CDC-FDA-NIOSH approved products.

"To date, UNC Health has maintained adequate supplies of NIOSH-approved PPE," Sickbert-Bennett said. "We feel confident we can maintain protection of the UNC Health workers with the variety of face masks and respirators tested as part of this JAMA-published study."

UNC Health infection prevention leaders are grateful for the partnership with the Center for Environmental Medicine, Asthma, and Lung Biology (CEMALB) and the EPA Human Studies Facility in Chapel Hill. Thanks to this collaboration, UNC Health can make evidence-based decisions on how to best protect our co-workers.

Dr. Clapp also led testing on other masks and homemade creations, using the same chamber and aerosol measurement equipment used for testing commercial masks. The UNC Office of Research Communications produced a Q and A with Dr. Clapp, along with a video about homemade masks based on his research.

What The Study Did: Researchers performed a series of FFE (fitted filtration efficiency) evaluations for a wide range of 29 respirators and face masks used by health care facilities, including expired N95 respirators, N95 respirators that have undergone sterilization, imported respirators approved by the U.S. Centers for Disease Control and Prevention, respirators not listed as approved, and surgical or procedure masks with ties and ear loops in this quality-improvement study.

Authors: Emily E. Sickbert-Bennett, Ph.D., M.S., of  UNC Health Care in Chapel Hill, North Carolina, is the corresponding author.

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

(doi:10.1001/jamainternmed.2020.4221)

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

Researchers at Fudan University in Shanghai, China have developed three different techniques that successfully replace almost all malfunctioning microglia - each technique with its own advantage in application.

The researchers published their findings on Aug 11, 2020 in Cell Reports.

Microglia are a specialized type of immune system cell that are found throughout the central nervous system (CNS), including brain, retina and spinal cord. Their main job is to protect the neurons of the central nervous system by gobbling up pathogens, cancer cells, foreign substances and cellular debris. They are sort of like a vacuum cleaner that the immune system uses to keep the central nervous system clean. Malfunctioning microglia are associated with many neurological diseases such as Alzheimer's, ALS and Parkinson's. Gene therapy to replace defective microglia-related genes with properly functioning ones offers tremendous potential to alleviate or perhaps one day even eliminate such diseases.

However, up till now, such efforts in the lab or testing on animals have largely failed long before any clinical trials on humans. Attempts at transplants of microglia or of bone marrow (because bone marrow is the main location in the body of production of new stem cells that can differentiate themselves into microglia) only end up replacing up to 5 percent of the faulty microglia. Other strategies that have been more successful when tested on mice require the animal to have a suppressed immune system and still be at the neonatal stage of life. This means that it is impossible for such a strategy to be used in any real-world clinical application for humans.

In an earlier study, the same team had noticed that when drugs had been used to almost completely eliminate all existing microglia, the few that remained had an astonishing ability to proliferate. This suggested to them that to get any microglia, native or transplanted, to substantially proliferate, you need the trigger of a completely empty microglial "niche" into which new microglia grow.

So the researchers replicated this effect by feeding normal adult mice for two weeks a diet that included a drug that inhibits the production of a molecule necessary for microglial survival. Only after all the microglia were wiped out, did the researchers attempt a bone marrow transplant. This time, some 93 percent of microglia were replaced in the brain, 99.5 percent in the retina, and 93 percent in the spinal cord.

They call this technique microglia replacement--because pretty much all the old microglia get replaced by new ones--by bone marrow transplant, or mrBMT.

"We pronounce the acronym for the technique 'Mister BMT'," said Bo Peng, the corresponding author and professor from the Institute for Translational Brain Research at Fudan University. "It's a cute name, but it makes it easy to say and to remember."

Despite the impressive replacement efficiency of mrBMT, bone marrow cells are rather scarce in clinical practice. So the researchers tried the same technique of eliminating existing microglia before transplant, but now with peripheral blood cells (PBC) instead of bone marrow cells. (Peripheral blood is the blood that circulates in much of the body, distinct from the blood cells that stay enclosed in the liver, spleen and other areas that have their own specialized type of blood). Such blood is abundant and easily acquired.

This second technique, called mrPB, (similarly pronounced "Mister PB"), replaced 80 percent of the microglia. So between the two techniques, there is trade-off: mrBMT offers close to full microglia replacement, but donor sources are hard to come by, while mrPB offers donor sources that are easy to come by, but the microglia replacement is slightly less efficient.

Sometimes though, a patient might need only the microglia in a specific part of the brain to be replaced without affecting the rest of the brain. So the researchers tweaked their concept still further. Using mrBMT first to replace resident cells with chemically sensitive microglia. After that, tamoxifen was applied to induce a fragment of a diphtheria toxin to kill off the replaced mrBMT cells. Meanwhile, they directly injected normally functioning microglia, which do not respond to tamoxifen, into a specific brain region with a syringe. While mrBMT and mrPB microglia still have some slight differences with regular microglia, the third technique, mrMT produces microglia almost indistinguishable from the normal kind.

"Each of the three approaches has its own merits and limits," said Peng, "but each is also more appropriate for different application scenarios. The hope is that all three of them open up a new era for treating microglia-associated CNS disorders."

Scientists have found that air pollution in the winter is associated with more hospitalisations for all strokes in Dublin.

The study, led by researchers from RCSI University of Medicine and Health Sciences, is published in the current edition of Cerebrovascular Diseases.

During winter months in Ireland, particularly in Dublin, higher levels of fine particles, coarse particles, sulphur dioxide and nitrogen dioxide are found in the air. The sources of these are solid fuel burning, such as coal, peat, and wood, as well as road traffic - especially diesel engines.

After accounting for other variables, such as temperature, humidity, day of the week and time, the researchers found that there was a statistically significant rise in the number of hospitalisations for strokes in Dublin zero to two days after a rise in air pollution.

For higher levels of nitrogen dioxide and sulphur dioxide, the researchers found both had an associated 3.5% higher risk of stroke. Higher levels of coarse particles correlated with a 3.2% higher risk, and finer particles correlated with a 2.4% higher risk.

The study marks the first time there has been a link demonstrated between short-term air pollution and stroke in Ireland.

"Every year, more than 10,000 people in Ireland have a stroke. Our research adds evidence that there needs to be a national ban on solid fuel burning to help in our efforts to reduce this number," said Dr Colm Byrne, the study's lead author and clinical lecturer in the RCSI Department of Geriatric and Stroke Medicine.

There was no significant association for all air pollutants found in the smaller urban area of Cork, but meta-analysis showed a significant association between hospitalisations for strokes and higher levels nitrogen dioxide and fine particles in the air.

"Because Ireland has relatively low air pollution when compared internationally, this highlights the need to introduce additional policy changes to reduce air pollution in all countries," said Professor David Williams, professor of stroke medicine at RCSI.

To protect humans against infection, a protein called MARCH8 tags the vesicular stomatitis virus (VSV) for destruction while it merely holds HIV hostage, a new study in eLife shows.

The findings reveal how a single protein can use multiple strategies to defend cells against viral infection. They could also improve our understanding of how HIV overcomes the human immune defence.

Previous studies have shown that MARCH8 stops HIV and VSV from entering human cells by targeting the viral proteins that are essential for these viruses to enter cells. But how the protein does this remained unclear. Researchers in Japan suspected that MARCH8 might flag an important VSV envelope protein for destruction by targeting a particular amino acid called lysine.

"The VSV G-glycoprotein (VSV-G) has a short tail containing five lysines, making it an ideal target," explains senior author Kenzo Tokunaga, Principal Investigator in the Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan. "The HIV envelope glycoprotein (Env), by contrast, has a very long tail with only two lysines, making it harder for MARCH8 to flag it for destruction."

To test their idea, Tokunaga and his team, including co-first authors and Postdoctoral Fellows Yanzhao Zhang and Takuya Tada, replaced the five lysines on the tail of VSV-G with five arginines - another type of amino acid. They also replaced the two lysines on the tail of HIV Env with two arginines. The change allowed VSV-G to escape MARCH8, but not HIV Env. This suggests that MARCH8 targets HIV Env and VSV-G using two different mechanisms.

Instead of marking HIV Env for destruction, the team found that MARCH8 holds it hostage, inhibiting its ability to make infectious copies of itself (replicate) and spread to other cells. When they created a mutant version of MARCH8 that lacks a specific pattern of the amino acid tyrosine, they found that HIV Env was able to escape, allowing the virus to replicate. This suggests that the tyrosine pattern in MARCH8 is essential to its HIV defence strategy.

"Our work may help explain why humans don't develop symptoms when infected with VSV, even though it can make some animals, mostly cows, horses and pigs, very ill," says Tokunaga. "The findings might also explain, at least in part, why HIV is able to hide from the human immune system, causing persistent infections that are difficult to treat."

On July 4, NASA's Transiting Exoplanet Survey Satellite (TESS) finished its primary mission, imaging about 75% of the starry sky as part of a two-year-long survey. In capturing this giant mosaic, TESS has found 66 new exoplanets, or worlds beyond our solar system, as well as nearly 2,100 candidates astronomers are working to confirm.

"TESS is producing a torrent of high-quality observations providing valuable data across a wide range of science topics," said Patricia Boyd, the project scientist for TESS at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "As it enters its extended mission, TESS is already a roaring success."

TESS monitors 24-by-96-degree strips of the sky called sectors for about a month using its four cameras. The mission spent its first year observing 13 sectors comprising the southern sky and then spent another year imaging the northern sky.

Now in its extended mission, TESS has turned around to resume surveying the south. In addition, the TESS team has introduced improvements to the way the satellite collects and processes data. Its cameras now capture a full image every 10 minutes, three times faster than during the primary mission. A new fast mode allows the brightness of thousands of stars to be measured every 20 seconds, along with the previous method of collecting these observations from tens of thousands of stars every two minutes. The faster measurements will allow TESS to better resolve brightness changes caused by stellar oscillations and to capture explosive flares from active stars in greater detail.

These changes will remain in place for the duration of the extended mission, which will be completed in September 2022. After spending a year imaging the southern sky, TESS will take another 15 months to collect additional observations in the north and to survey areas along the ecliptic - the plane of Earth's orbit around the Sun - that the satellite has not yet imaged.

TESS looks for transits, the telltale dimming of a star caused when an orbiting planet passes in front of it from our point of view. Among the mission's newest planetary discoveries are its first Earth-size world, named TOI 700 d, which is located in the habitable zone of its star, the range of distances where conditions could be just right to allow liquid water on the surface. TESS revealed a newly minted planet around the young star AU Microscopii and found a Neptune-size world orbiting two suns.

In addition to its planetary discoveries, TESS has observed the outburst of a comet in our solar system, as well as numerous exploding stars. The satellite discovered surprise eclipses in a well-known binary star system, solved a mystery about a class of pulsating stars, and explored a world experiencing star-modulated seasons. Even more remarkable, TESS watched as a black hole in a distant galaxy shredded a Sun-like star.

Missions like TESS help contribute to the field of astrobiology, the interdisciplinary research on the variables and conditions of distant worlds that could harbor life as we know it, and what form that life could take.

PHILADELPHIA - Running is one of the most popular forms of exercise, enjoyed by a broad range of age groups and skill levels. More women are running recreationally compared to men; specifically 54% of runners are female as indicated by a 2018 National Runner Survey. Women, however, are at least twice as likely as men to develop stress fractures, an injury that impacts around 20% of runners. However, information is still lacking on how to best prevent and treat stress fractures in women. New pilot research from Jefferson suggests physiological factors that could be included in routine screening for stress fracture risk, as well as changes in training approach to aid in prevention.

The researchers examined physiological differences that might contribute to increased risk of stress fractures in a study published in Sports Health and also surveyed women's perception of risk and behaviors that contribute to stress fractures in a separate study published in Physical Therapy in Sport.

"Most of the literature focuses on elite runners or athletes," says Therese Johnston, PT, PhD, MBA, Professor in the Department of Physical Therapy and first author of both studies. "It was important for us to capture the regular or average female runner in these studies, and the main goal was to see how we can prevent a first or subsequent fracture."

Both studies surveyed the same group of 40 female recreational runners, age 18-65 years. 20 women had a history of running-related stress fractures, and they were matched according to age and running abilities with 20 women with no history of stress fractures. The two studies aimed to assess what contributed to risk of stress fractures, from the physiological, such as - bone structure and density, muscle mass, hormonal status, to ones influenced by training routine, such as training intensity, nutrition, insufficient strengthening, and ignoring pain.

"This mixed methods approach provides a richer context and a more detailed picture of the practices and risks that contribute to stress fractures in every-day women runners," says Jeremy Close, MD, Associate Professor in Family and Sports Medicine and one of the lead authors on the research. "It also tells us how perceived risk informs physiological risk."

For the study focused on physiological factors, the subjects underwent a comprehensive blood panel that examined levels of hormones like estradiol and testosterone, vitamins and minerals important for bone health such as vitamin D and calcium, and bone markers. They also underwent dual energy x-ray absorptiometry (DXA) to test for bone mineral density. The researchers found that while there was no difference in estradiol hormone levels between the two groups, women who had a stress fracture history reported menstrual changes or irregular periods as a result of their training, or during peak training times. The blood panel also examined markers for bone formation and resorption, and pointed to increased bone turnover in the group of women with stress fractures. They also found through the DXA testing that women with a history of stress fractures had lower hip bone mineral density compared to women with no history of stress fractures, indicating decreased bone strength that could increase risk of injury.

"DXA for bone density and blood testing for bone markers are not routinely performed in this population - they are usually reserved for post-menopausal women --so we may be missing important clinical indicators for stress fractures in these women," says Dr. Johnston. "While the link between menstrual changes and bone strength is unclear, our findings also indicate that asking female runners about any menstrual irregularities during heavier training times is important during routine screening."

For the study investigating women's self-perception of risk, interviews were conducted with the goals of finding out which factors women thought were associated with stress fractures or maintaining bone health while running. Several themes emerged from these interviews, specifically, compared to women without stress fractures, women with histories of stress fractures had increased their training load more quickly. Also, while they knew of the importance of nutrition and strengthening exercises, women with a history of stress fracture more often reported not having or making the time for a balanced diet and proper cross-training to complement their running regimen.

Finally, women in this group reported pushing through the pain and running despite an injury more often than those without stress fracture. "In the interviews, it sounded like these women had trouble knowing which pain was normal, and which pain was abnormal. They also reported not always receiving appropriate guidance from healthcare providers on how to progress running safely," says Dr. Johnston.

"It is clear that there needs to be more guidance from healthcare providers for woman runners on how to prevent stress fractures" says Dr. Close. "It can be very frustrating for these women who are on a path to wellness, but are impeded by an injury that can take several months to heal. If they don't have the proper guidance on how to return to running safely, they risk a second injury."

"We hope that our findings will encourage more thorough and routine screening in women runners for bone density and strength," says Dr. Johnston, "as well as a comprehensive education plan on how to balance running with cross-training, and how to interpret pain cues from the body, to help women differentiate between normal aches and pains and indicators of a serious injury."

Dr. Johnston plans to continue this research by studying women with acute stress fractures as they start running again, in order to identify factors related to successful or unsuccessful return to running following a stress fracture. The study will include Dr. Close as well as Marc Harwood, MD, Service Chief in the Department of Non-Operative Sports Medicine at Rothman Orthopaedic Institute.

CATONSVILLE, MD, August 11, 2020 - The Transportation Security Administration (TSA) has reported that it found 4,432 firearms in carry-on baggage at airport security checkpoints in 2019, and more than 20,000 firearms since 2014. New research published in the INFORMS Journal on Applied Analytics suggests that they could have found even more.

The initial reaction to these numbers is shock and concern. It's easy to jump to conclusions about airline security, but Sheldon H. Jacobson of the University of Illinois at Urbana-Champaign is encouraging air travelers to look closer.

Jacobson was funded in 2001 by the National Science Foundation (NSF) to conduct research on risk-based security and its impact on improving airport security following 9/11. This research provided the technical foundations for PreCheck, a prescreening program for airline passengers that conducts background checks and fingerprinting prior to travel to ensure a speedy travel experience. The amount of passengers prescreened through PreCheck rose from 2014 through 2017, leveling off since then.

While this new study, "Using Risk-based Security to Quantify the Number of Firearms Missed at Airport Security Checkpoints," reveals an uptick in firearms found at airport security checkpoints from 2014 through 2019, and estimates thousands more missed, the results aren't bad, they're good.

"This 2018 and 2019 data trend suggests that increases in firearms detected since 2017 are largely due to more passengers being screened using PreCheck," said Jacobson, a founder professor of computer science at the University of Illinois. "Moving forward, the most effective way for the TSA to miss fewer firearms in carry-on baggage at airport security checkpoints is to increase the number of PreCheck qualified screenings."

What we are seeing is an enhanced focus from TSA agents because they can slow down, as lines are being reduced due to prescreened passengers, and pay closer attention to higher risk passengers who have not been prescreened.

Jacobson used publicly available data on firearm detection, number of passengers screened, and the fraction of passenger screenings in PreCheck lanes to estimate the number of firearms missed at airport security checkpoints in the United States. Under the assumption that firearms are only being detected in standard screening lanes he estimates as many as 4,600 firearms may have been missed by TSA officers in carry-on baggage at airport security checkpoints during the above time frame.

Another point to note, amid the current COVID-19 pandemic, with 94% fewer travelers from March 22, 2020 through April 22, 2020 and 75% fewer passengers in July 2020, officers working standard lanes are more focused, so miss less, creating a PreCheck-like environment in standard checkpoint lanes. Ironically, the 65% miss rate, cited in a recent editorial written by Jacobson about the impact of this reduced number of passengers, is consistent with the numbers in the new paper.

"Although the TSA has missed thousands of firearms at airport security checkpoints, none of these missed items have resulted in any malicious activity," adds Jacobson. "Given that risk-based security is more about people rather than items, partitioning passengers according to their risk is the most effective means to ensure a secure air system for all."

The study comments that making PreCheck available to anyone (at a cost below the current $85 for five years) wishing to enroll and undergo the background check, would enhance overall air system security and improve passenger service, a win-win for all. This would allow TSA agents to search for needles in a smaller haystack, if you will. Less hay means that it is easier to identify needles.

EVANSTON, Ill. -- Northwestern University researchers have uncovered a new vulnerability in the novel coronavirus' infamous spike protein -- illuminating a relatively simple, potential treatment pathway.

The spike protein contains the virus' binding site, which adheres to host cells and enables the virus to enter and infect the body. Using nanometer-level simulations, the researchers discovered a positively charged site (known as the polybasic cleavage site) located 10 nanometers from the actual binding site on the spike protein. The positively charged site allows strong bonding between the virus protein and the negatively charged human-cell receptors.

Leveraging this discovery, the researchers designed a negatively charged molecule to bind to the positively charged cleavage site. Blocking this site inhibits the virus from bonding to the host cell.

"Our work indicates that blocking this cleavage site may act as a viable prophylactic treatment that decreases the virus' ability to infect humans," said Northwestern's Monica Olvera de la Cruz, who led the work. "Our results explain experimental studies showing that mutations of the SARS-CoV-2 spike protein affected the virus transmissibility."

The research was published online last week in the journal ACS Nano.

Olvera de la Cruz is the Lawyer Taylor Professor of Materials Science and Engineering in Northwestern's McCormick School of Engineering. Baofu Qiao, a research assistant professor in Olvera de la Cruz's research group, is the paper's first author.

Made up of amino acids, SARS-CoV-2's polybasic cleavage sites have remained elusive since the COVID-19 outbreak began. But previous research indicates that these mysterious sites are essential for virulence and transmission. Olvera de la Cruz and Qiao discovered that polybasic cleavage site is located 10 nanometers from human cell receptors -- a finding that provided unexpected insight.

"We didn't expect to see electrostatic interactions at 10 nanometers," Qiao said. "In physiological conditions, all electrostatic interactions no longer occur at distances longer than 1 nanometer."

"The function of the polybasic cleavage site has remained elusive," Olvera de la Cruz said. "However, it appears to be cleaved by an enzyme (furin) that is abundant in lungs, which suggests the cleavage site is crucial for virus entry into human cells."

With this new information, Olvera de la Cruz and Qiao next plan to work with Northwestern chemists and pharmacologists to design a new drug that could bind to the spike protein.

A first-of-its-kind study by researchers from the Boston University School of Public Health (BUSPH) shows a decline in deaths related to atrial fibrillation (irregular heartbeat) over the last 45 years.

But the study, published in the journal BMJ, finds that the increasingly common condition still takes an average of two years off of a person's life, compared to three years back in the 1970s and early 1980s.

"The prognosis of individuals with atrial fibrillation has improved over time, but atrial fibrillation is still associated with a major gap in life expectancy as compared to individuals without atrial fibrillation," says study senior author Dr. Ludovic Trinquart, associate professor of biostatistics at BUSPH.

Trinquart and colleagues at BU and in Denmark used data from the BU-based, multigenerational Framingham Heart Study, the longest-running cardiovascular health study in the United States.

"The Framingham Heart Study is one of the only studies in the world that allow studying such temporal trends," says study lead author Dr. Nicklas Vinter, a physician at Silkeborg Regional Hospital and doctoral student at Aarhus University in Denmark.

The researchers analyzed health data from three generations of Framingham Heart Study participants from 1972 to 2015, tracking the likelihood of a participant dying 10 years after an atrial fibrillation diagnosis, compared with someone of the same age, sex, and with otherwise similar health.

In the first period (1972-1985), a participant with atrial fibrillation lived an average of 2.9 fewer years 10 or more years after diagnosis than a comparison participant without atrial fibrillation.

In the second period (1986-2000) the gap narrowed to 2.1 years, and in the third period (2001-2015) it was 2.0 years.

"Improvement in the excess mortality associated with atrial fibrillation may be explained by continued improvements in early detection, management, and treatment," Trinquart says. "But the findings of this new study highlight that atrial fibrillation remains a very serious condition. Advances in prevention will be essential to stem the epidemic of atrial fibrillation and reduce its associated mortality."

Of ever-increasing concern for operating a tactical communications network is the possibility that a sophisticated adversary may detect friendly transmissions. Army researchers developed an analysis framework that enables the rigorous study of the detectability of ultraviolet communication systems, providing the insights needed to deliver the requirements of future, more secure Army networks.

In particular, ultraviolet communication has unique propagation characteristics that not only allow for a novel non-line-of-sight optical link, but also imply that the transmissions may be harder for an adversary to detect.

Building off of experimentally validated channel modeling, channel simulations, and detection and estimation theory, the developed framework enables the evaluation of tradeoffs associated with different design choices and the manner of operation of ultraviolet communication systems, said Dr. Robert Drost of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory.

"While many techniques have been proposed to decrease the detectability of conventional radio-frequency, or RF, communications, the increased atmospheric absorption of deep-ultraviolet wavelengths implies that ultraviolet communication, or UVC, has a natural low-probability-of-detection, or LPD, characteristic," Drost said.

"In order to fully take advantage of this characteristic, a rigorous understanding of the LPD properties of UVC is needed."

In particular, Drost said, such understanding is essential for optimizing the design and operation of UVC systems and networks and for predicting the quality of the LPD property in a given scenario, such as using UVC to securely network a command post that has an estimate of the direction and distance to the adversary.

Without such a predictive capability, he said, users would lack the guidance needed to know the extent and limit of their detectability, and this lack of awareness would substantially limit the usefulness of the LPD capability.

The researchers, including Drs. Mike Weisman, Fikadu Dagefu, Terrence Moore and Drost from CCDC ARL and Dr. Hakan Arlsan, Oak Ridge Associated Universities postdoctoral fellow at the lab, demonstrated this by applying their framework to produce a number of key insights regarding the LPD characteristics of UVC, including:

LPD capability is relatively insensitive to a number of system and channel properties, which is important for the robustness of the LPD property
Adversarial line-of-sight detection of a non-line-of-sight communication link is not as significant of a concern as one might fear
Perhaps counter to intuition, steering of a UVC transmitter does not appear to be an effective detection-mitigation strategy in many cases
Line-of-sight UVC link provides non-line-of-sight standoff distances that are commensurate with the communication range

Prior modeling and experimental research has demonstrated that UVC signals attenuate dramatically at long distance, leading to the hypothesis that UVC has a fundamental LPD property, Drost said. However, there has been little effort on rigorously and precisely quantifying this property in terms of the detectability of a communication signal.

"Our work provides a framework enabling the study of the fundamental limits of detectability for an ultraviolet communication system meeting desired communication performance requirements," Drost said.

Although this research is focused on longer-term applications, he said, it is addressing the Army Modernization Priority on Networks by developing the fundamental understanding of a novel communications capability, with a goal of providing the Soldier with network connectivity despite challenging environments that include adversarial activity.

"The future communications and networking challenges that the Army faces are immense, and it is essential that we explore all possible means to overcoming those challenges," Drost said. "Our research is ensuring that the community has the fundamental understanding of the potential for and limitations of using ultraviolet wavelengths for communications, and I am confident that this understanding will inform the development of future Army networking capabilities. Conducting fundamental research that impacts decision making and Army technologies is why we work for the Army, and it is very satisfying to know that our work will ultimately support the warfighter in his or her mission."

The researchers are currently continuing to develop refined understanding of how best to design and operate ultraviolet communications, and an important next step is the application of this framework to understand the detectability of a network of ultraviolet communications systems.

Another key effort involves the experimental characterization, exploration and demonstration of this technology in a practical network using ARL's Common Sensor Radio, a sophisticated mesh-networking radio designed to provide robust and energy-efficient networking.

This research supports the laboratory's FREEDOM (Foundational Research for Electronic Warfare in Multi-Domain Operations) Essential Research Program goal of studying the integration of low-signature communications technologies with advanced camouflage and decoy techniques.

According to Drost, the work is also an on-ramp to studying how ultraviolet communications and other communications modalities, including conventional radio-frequency communications, can operate together in a seamless and autonomous extremely heterogeneous network, which the researchers believe is needed in order to fully realize the benefits of individual novel communication technologies.

As they make continued progress on these fundamental research questions, the researchers will continue to work closely with their transition partner at the CCDC C5ISR (Command, Control, Computers, Communications, Cyber, Intelligence, Surveillance and Reconnaissance) Center to push ultraviolet communications toward nearer term transition to the warfighter.

A new animation of night-time imagery from NASA-NOAA's Suomi NPP satellite revealed how the Eastern Pacific Ocean's Elida transformed into a hurricane over a three-day period.

NASA's Night-Time View of Elida's Intensification

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a night-time image of Hurricane Elida during the early morning hours of Aug. 11 (8 p.m. EDT on Aug. 10). The storm had intensified into a hurricane and an eye was clearly apparent, surrounded by powerful thunderstorms around it.

At NASA's Goddard Space Flight Center in Greenbelt, Md. an animation of night-time imagery from NASA-NOAA's Suomi NPP satellite shows the development and intensification of Hurricane Elida in the Eastern Pacific Ocean from Aug. 9 to 11, 2020 at 0000 UTC (which is 8 p.m. EDT Aug. 8 to 10). On Aug. 9, Elida appeared somewhat shapeless, and by the night-time hours of Aug.10, the storm took on a general tropical cyclone shape with bands of thunderstorms wrapping into the low-level center. Elida became a hurricane by 5 p.m. EDT (2100 UTC) on Aug. 10. By Aug. 11, Elida had a tight circulation of powerful thunderstorms around the center and an eye was apparent on the night-time imagery. The animation was created using the NASA Worldview application.

Hurricane Elida's Status on Aug. 11

At 11 a.m. EDT (1500 UTC) on Aug. 11, the National Hurricane Center (NHC) noted the center of Hurricane Elida was located near latitude 21.3 degrees north and longitude 113.8 degrees west. That is about 275 miles (440 km) west-southwest of the southern tip of Baja California, Mexico.

Elida was moving toward the northwest near 14 mph (22 kph). A west-northwestward to northwestward motion with a decrease in forward seed is expected during the next several days. Maximum sustained winds have increased to near 100 mph (155 kph) with higher gusts. Elida is now a Category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale. Hurricane-force winds extend outward up to 15 miles (30 km) from the center and tropical-storm-force winds extend outward up to 70 miles (110 km). The estimated minimum central pressure is 975 millibars.

Rapid weakening is expected to begin tonight as Elida moves over colder water, and the cyclone is expected to weaken to a tropical storm on Wednesday and degenerate to a remnant low pressure area on Thursday, Aug. 13.

BROOKLYN, New York, Tuesday, August 11, 2020 - Surges in firearm acquisition after mass shootings is a well-documented phenomenon, but analytic research into the causes of this behavior -- be it driven by a desire for self-protection, or a fear that access to firearms will be curtailed -- is sparse.

A new study applying a data science methodology of state-by-state data to infer causal relationships finds that the decision to purchase a gun is driven by the latter concern -- stricter regulations on gun purchase and ownership -- more than by a desire to protect oneself after a mass shooting. The study, led by Maurizio Porfiri, Institute professor at NYU Tandon, is his second in a year to examine causative factors driving consumer firearm-purchase behavior.

It also presages a much more comprehensive effort backed by a $2 million grant from the National Science Foundation (NSF). The project, funded under the NSF's LEAP HI program (Leading Engineering for America's Prosperity, Health and Infrastructure), will examine causal relationships between potentially contributing factors as firearm prevalence, state legislation, media exposure, and people's opinion on firearm-related harms, at the individual, state, and nation levels.

This will be the first research of its kind to unfold the firearm ecosystem simultaneously on three levels:

Macroscale: causality between firearm prevalence and firearm-related harms at the national level

Mesoscale: policy diffusion across states

Microscale: individual opinions about firearm safety

"By cogently linking these scales, we will lay the foundation for analysis, diagnostics, and prediction of firearm-related harms," said Porfiri.

The research effort, 'Understanding and Engineering the Ecosystem of Firearms: Prevalence, Safety, and Firearm-Related Harms, will be orchestrated by a multidisciplinary team comprising co-principal investigators Oded Nov, a professor of Technology Management and Innovation at NYU Tandon; Igor Belykh, a professor of Mathematics and Statistics at Georgia State University; James Macinko, a professor of Health Policy and Management at the University of California Los Angeles; and Rifat Sipahi, a professor of Mechanical and Industrial Engineering at Northeastern University. Also involved are Shinnosuke Nakayama, formerly a post-doctoral associate in Porfiri's lab at NYU Tandon and now a data research scientist at the Center for Ocean Solutions at Stanford University; and Maria Grillo, a project associate in the Institute for Invention, Innovation, and Entrepreneurship at NYU Tandon.

New research comprises three studies focused on state-level data

The newly-published research, "Self-protection versus fear of stricter firearm regulations: examining the drivers of firearm acquisitions in the aftermath of a mass shooting," appears in the Cell Press journal Patterns. It comprises three studies based on data the team collected on mass shootings, federal background checks related to firearm purchases, media output on firearm control and shootings from several media outlets in the country, and firearm safety laws from 1999 to 2017.

The authors of the new study, including Roni Barak-Ventura, research assistant in Porfiri's Dynamical Systems Laboratory and Manuel Ruiz Marín of the Technical University of Cartagena, Spain, puts forward a data science framework, based on the mathematical construct of transfer entropy to discover causal links between multiple variables by examining the degree to which one variable influences another. In these analyses, influence is defined as an improved ability to make predictions about the future status of a variable (in this case, background checks) based on present knowledge of another variable (for example, media stories about gun control policy).

The team first conducted a cluster analysis to partition states according to the restrictiveness of their firearm-related legal environment. That was followed by a transfer entropy analysis to unveil causal relationships at the state-level between mass shootings, media coverage of gun violence, media coverage of firearm regulations, and background checks.

The first study examined how the occurrence of mass shootings in the nation, media reports about shootings, and media reports on firearm control influence the number of background checks in firearm restrictive and firearm permissive states. The researchers found that increased media coverage of firearm control influenced background checks in permissive states.

The second study tested whether the location of a mass shooting had a potential influence on the number of background checks across the country. The researchers found that the number of background checks in one state was not significantly affected by mass shootings in another, irrespective of their location or the state's restrictiveness.

The third study looked at the influence on the number of background checks in a given state of background checks in geographically neighboring states. The team found a strong interaction among states, whether they are permissive or restrictive, so that firearm purchases in a state determine purchases in neighboring state.

"The analysis suggests that fear of stricter firearm regulations is a stronger driver than the desire of self-protection for firearm acquisitions," said Porfiri, who is on a research sabbatical at the Technical University of Cartagena, Spain. "This fear is likely to cross states' borders, thereby shaping a collective pattern of firearm acquisition throughout the nation."

Ruiz Marín added that "This research brings forward an alternative data science methodology to examine causal links in spatio-temporal data, with potential application to the study of a number of problems in economics and social sciences."

Porfiri's first study of this kind, published in Nature Human Behavior in September, 2019, similarly applied entropy transfer techniques to mass shootings and the publicity around them, and demonstrated the potential of quantitative methods, grounded in engineering principles, to elucidate key aspects of the firearm ecosystem.

"Engineering, by definition, applies mathematical tools and scientific principles to real-world challenges. Porfiri's work -- the importance of which is reflected in the generosity of the NSF LEAP HI award -- is proof positive that engineering offers solutions beyond hardware, software, chemical innovations, and physical structures," said Jelena Kovačevi?, Dean of the NYU Tandon School of Engineering. "Indeed, Porfiri's research brings hard data and rigorous analytics to bear on the sometimes amorphous patterns and influences that drive our society and, ultimately, shine a light on the machinery of our democracy."

ITHACA, N.Y. - Machine learning can assess the effectiveness of mathematical tools used to predict the movements of financial markets, according to new Cornell research based on the largest dataset ever used in this area.

The researchers' model could also predict future market movements, an extraordinarily difficult task because of markets' massive amounts of information and high volatility.

"What we were trying to do is bring the power of machine learning techniques to not only evaluate how well our current methods and models work, but also to help us extend these in a way that we never could do without machine learning," said Maureen O'Hara, the Robert W. Purcell Professor of Management at the SC Johnson College of Business.

O'Hara is co-author of "Microstructure in the Machine Age," published July 7 in The Review of Financial Studies.

"Trying to estimate these sorts of things using standard techniques gets very tricky, because the databases are so big. The beauty of machine learning is that it's a different way to analyze the data," O'Hara said. "The key thing we show in this paper is that in some cases, these microstructure features that attach to one contract are so powerful, they can predict the movements of other contracts. So we can pick up the patterns of how markets affect other markets, which is very difficult to do using standard tools."

Markets generate vast amounts of data, and billions of dollars are at stake in mining that data for patterns to shed light on future market behavior. Companies on Wall Street and elsewhere employ various algorithms, examining different variables and factors, to find such patterns and predict the future.

In the study, the researchers used what's known as a random forest machine learning algorithm to better understand the effectiveness of some of these models. They assessed the tools using a dataset of 87 futures contracts - agreements to buy or sell assets in the future at predetermined prices.

"Our sample is basically all active futures contracts around the world for five years, and we use every single trade - tens of millions of them - in our analysis," O'Hara said. "What we did is use machine learning to try to understand how well microstructure tools developed for less complex market settings work to predict the future price process both within a contract and then collectively across contracts. We find that some of the variables work very, very well - and some of them not so great."

Machine learning has long been used in finance, but typically as a so-called "black box" - in which an artificial intelligence algorithm uses reams of data to predict future patterns but without revealing how it makes its determinations. This method can be effective in the short term, O'Hara said, but sheds little light on what actually causes market patterns.

"Our use for machine learning is: I have a theory about what moves markets, so how can I test it?" she said. "How can I really understand whether my theories are any good? And how can I use what I learned from this machine learning approach to help me build better models and understand things that I can't model because it's too complex?"

Huge amounts of historical market data are available - every trade has been recorded since the 1980's - and vast volumes of information are generated every day. Increased computing power and greater availability of data have made it possible to perform more fine-grained and comprehensive analyses, but these datasets, and the computing power needed to analyze them, can be prohibitively expensive for scholars.

In this research, finance industry practitioners partnered with the academic researchers to provide the data and the computers for the study as well as expertise in machine learning algorithms used in practice.

"This partnership brings benefits to both," said O'Hara, adding that the paper is one in a line of research she, Easley and Lopez de Prado have completed over the last decade. "It allows us to do research in ways generally unavailable to academic researchers."

BYRON BAY, Australia (August 11, 2020) - A study by WCS and partners produced new analyses to pinpoint the most important forests for biodiversity conservation remaining in Central Africa. The results highlight the importance of the Democratic Republic of Congo (DRC), northern Republic of Congo, and much of Gabon as the most important countries in Central Africa for safeguarding biodiversity and intact forests.

The study combines new datasets on forests to identify where the most intact forests remain across this vast area with previous work that identified strongholds for bonobos, forest elephants, gorillas, and chimpanzees across the region. The results reveal that the Democratic Republic of Congo has the largest amount of priority areas in the region, containing more than half, followed by Gabon, the Republic of Congo, and Cameroon. Specific regions include: the Salonga area and East-central DRC; northern Republic of Congo; extensive areas in Gabon including Crystal Mountains (Monts de Cristal) and Chaillu Mountains (Monts de Chaillu), areas along the coast, and the north-east.

The authors compared their approach to one that solely prioritizes forest intactness based on a forest fragmentation and degradation model, and models of human pressures on the forest, to one that aims to achieve only biodiversity representation objectives, and one that combines them all. They found that when priorities are only based on forest intactness without considering biodiversity representation, there are significantly fewer biodiversity benefits and vice versa.

The study's lead author, Dr. Hedley Grantham, WCS Director of Conservation Planning, said: "This study shows that just prioritizing forests based on their condition will trade-off biodiversity representation benefits, and vice versa will miss locations for preserving the remaining intact forests important for many species in an increasingly human-dominated world. Our approach can inform various types of conservation strategies, including land-use planning, carbon payments, protected area expansion, community forest management, and forest concession plans."

The forests of Central Africa contain some of Earth's few remaining intact forests. These forests are increasingly threatened by infrastructure development, agriculture, and unsustainable extraction of natural resources (e.g., minerals, bushmeat, and timber), all of which is leading to deforestation and forest degradation, particularly defaunation, and hence causing declines in biodiversity and a significant increase in carbon emissions.

Co-author WCS Conservation Scientist Fiona "Boo" Maisels said: "By highlighting areas of high importance for biodiversity and forest intactness, our analysis can guide national infrastructure and agricultural development plans to the areas of low conservation value, thus simultaneously enabling sustainable development and sound conservation stewardship"

Olivia Rickenbach led the development of guidelines on High Conservation Value (HCV) identification and management for Forest Stewardship Council (FSC) certified forest management in the Congo Basin. She notes: "FSC initiated and coordinated the collaboration that produced this analysis. It was sparked by the lack of readily available data and decision-making tools which could identify the most important zones for biodiversity conservation at a landscape level. The analysis was also needed due to the regional critique of IFLs (Intact Forest Landscapes) as indicators to define such areas. Draft HCV guidelines were approved in November 2019 by the regional working group supervising this task; they now propose this method and data to identify HCV 2 areas."