Culture

What The Study Did: This observational study assessed the association between the use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers with the likelihood of testing positive for coronavirus disease 2019 (COVID-19).

Authors: Ankur Kalra, M.D., of the Cleveland Clinic in Akron, Ohio, 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/jamacardio.2020.1855)

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

By manipulating the expression of one gene, geneticists can induce a form of "stress memory" in plants that is inherited by some progeny, giving them the potential for more vigorous, hardy and productive growth, according to Penn State researchers, who suggest the discovery has significant implications for plant breeding.

And because the technique is epigenetic -- involving the expression of existing genes and not the introduction of new genetic material from another plant -- crops bred using this technology could sidestep controversy associated with genetically modified organisms and food.

"One gene, MSH1, gives us access to what is controlling a broad array of plant resiliency networks," said Sally Mackenzie, professor of plant science in the College of Agricultural Sciences and professor of biology in the Eberly College of Science. "When a plant experiences a stress such as drought or prolonged extreme heat, it has the ability to adjust quickly to its environment to become phenotypically 'plastic' -- or flexible."

There are many ways to inactivate the MSH1 gene, researchers explain, and in this context they all work. In well-studied plant species, like Arabidopsis, tomato or rice, it is possible to identify mutations in the gene. In others, and for commercial testing, it is possible to design a transgene that uses "RNA interference" to specifically target MSH1 for gene silencing. Any method that silences MSH1 results in very similar outcomes, they report.

"When plants are modified epigenetically, they can modify many genes in as simple a manner as possible," Mackenzie pointed out. That includes adjusting the circadian clock -- detecting light and triggering growth and reproductive phases -- and modifying hormone responses to give them maximum flexibility, making them more resilient.

Plants that "detect" stress after the MSH1 gene is silenced can adjust their growth and change root configuration, limit above-ground biomass, delay flowering time and alter their response to environmental stimuli. Those responses are "remembered," researchers reported, and passed in selective breeding through many generations.

"In our research, we show that this memory condition is heritable by progeny but occurs in only a proportion of the progeny -- so that there are memory and non-memory full siblings," said Mackenzie, the Lloyd and Dottie Huck Chair for Functional Genomics. "That results in definable gene expression changes that impact a plant's phenotypic 'plasticity.' We suggest that all plants have this capacity, and that the condition that we describe is likely to be an important part of how plants transmit memory of their environment to precondition progeny."

By adjusting the epigenetic architecture of a plant, researchers were able to access its resiliency network, and see how genes are expressed quickly and broadly to adjust a plant's growth to adapt to the environment, noted Mackenzie, director of the Plant Institute at Penn State.

The researchers identify pathways that enhance root growth and plant vigor -- increasing yield. They present their results today (May 5) in Nature Communications. When an MSH1-modified plant is crossed or grafted, this enhanced plant vigor becomes quite pronounced.

Researchers contend that plants can be "reprogrammed" epigenetically to express genes differently without altering genotype, which constitutes a non-traditional approach to breeding. Because they can now identify gene networks that appear to be targeted by this manipulation, researchers report that plants have mechanisms designed to address stress or alter growth, and these can be accessed.

The researchers focused their efforts on the small flowering plant, Arabidopsis, or rockcress, a relative of cabbage and mustard in the Brassica family. It is one of the model organisms used for studying plant biology and the first plant to have its entire genome sequenced. Arabidopsis is useful for genetic experiments because of its short generation time and prolific seed production through self-pollination. Researchers grew five generations of Arabidopsis to study "memory" and "non-memory" plants.

In follow-up research already underway in Mackenzie’s lab, the researchers have suppressed MSH1 genes in tomato and soybean plants and grafting experiments have been field tested with excellent yield results. A large-scale experiment growing MSH1-modified canola is now in the works. This technology is part of a start-up company called EpiCrop Technologies Inc. that was co-founded on MSH1 technology and its utility in agriculture.

A new survey of app-based ride-hailing and food and grocery-delivery workers in San Francisco underscores the financial vulnerability of workers in the gig economy--and the coronavirus has made their plight much worse, according to findings released today (Tuesday, May 5) by researchers at the University of California, Santa Cruz.

The unique, in-person survey reached 643 workers with Uber, Lyft, Doordash, GrubHub, Instacart, and Shipt early this year. When the shelter-in-place order took effect, researchers developed an additional two-week, online survey to capture the effects of the pandemic on app-based workers--a growing population that enjoys little job security and few employment rights.

The baseline survey reveals a workforce that is 56% immigrant, mostly male, and that struggles to make ends meet, with many relying on public assistance despite working an average of 40 hours per week. Since the pandemic, the online survey revealed, more than half have lost 75-100% of their income. The findings were published in a report titled, "On-demand and on-the-edge: Ride-hailing and Delivery Workers in San Francisco."

"This is an incredibly vulnerable workforce, and many were just on the edge before the coronavirus crisis," said lead researcher Chris Benner, a professor of environmental studies and sociology and the director of the Institute for Social Transformation at UCSC. "The crisis has put them over the edge. Because of their employment status, they fall through a lot of cracks in the relief packages that have been approved by the state and federal governments."

The initial survey was conducted over six weeks from February 1 through mid-March. Survey takers recruited participants through the apps themselves by hiring workers and asking if they'd like to participate. The 20-minute survey was administered in person, and those who participated received a $20 gift card. The response rate was 70% among ride-hailing workers and 15% among food-delivery workers.

The outbreak of the coronavirus crisis prompted the research team to pivot to an online survey, which was conducted the second and third weeks of April. Participants were recruited through organized networks, including closed Facebook groups, and a total of 219 app-based workers responded.

"We surveyed the same workforce at two different points in time," said Benner. "The first gives us a picture of these workers under normal work circumstances, and the second is a snapshot of the impacts of COVID on this workforce."

Full-time work but not enough to get by

The baseline survey, which reached 407 ride-hailing workers and 236 food-delivery workers, revealed a workforce on the margins:

21% of participants have no health insurance, and another 30% depend on public insurance sources, such as Covered California or Medi-Cal

15% receive some form of public assistance, including 13% of food-delivery workers who depend on food stamps

45% report they could not handle a $400 emergency expense without borrowing money

Half the participants report working 40 or more hours per week in app-based work, and nearly 40% have worked more than two years for their "survey app"--they app they were working on when recruited for the survey.

"This is not a 'gig.' This is full-time work for the majority of these workers," said Benner. "More than one-third are supporting children and nearly half are supporting other adults."

Respondents reported median weekly earnings of $900 for ride-hailing workers and $500 for food-delivery workers, but those earnings drop considerably when adjusted for expenses such as gas, vehicle service, and cleaning. And the gap between workers' own estimates of expenses, compared to per-mile expenses allowed by the IRS, is considerable: When using the IRS estimates, fully 21% of workers net zero for their labor, said Benner.

"We estimate that twenty percent of ride-hailing workers are actually losing money to drive, when you account for all of their expenses," said Benner.

Impacts of the coronavirus pandemic

Preliminary findings of the online survey, including the drop in income, were shared with the San Francisco Local Agency Formation Commission (SF LAFCo), which commissioned the baseline survey, on April 21.

"With the shelter-in-place order in effect, ride-hailing workers were earning a fraction of what they'd made in February, but these workers were living on the edge financially already, so anything they can bring in is necessary," said Benner.

The coronavirus crisis prompted 18% of surveyed ride-hailing workers to shift to food delivery, but the biggest impact was on those who were not working at all: 24% had stopped working by mid-April, for fear of contracting the virus or other reasons.

Because app-based companies continue to classify their workers as independent contractors, despite the passage in 2019 of California Assembly Bill 5 designed to make them employees, workers are not typically able to access unemployment benefits. Although the federal CARES Act expanded eligibility to some independent contractors, app-based workers have trouble providing the required documentation of their previous earnings, said Benner.

Policy implications

The two-pronged survey results shed light on the needs of app-based workers, particularly in a city like San Francisco, which has some of the most progressive fair-labor standards in the country, said Benner. "These workers need and deserve greater economic security," he said.

Policymakers must ensure that city and state employment laws are enforced, including minimum wage laws, and that ride-hailing and delivery workers have access to health insurance and unemployment benefits, said Benner. He added that the pandemic has exposed a need for improved safety and health protection of workers and paid sick leave, as well as stronger public health protections.

Meanwhile, owners of app-based companies are backing a ballot initiative that would exempt them from employer regulations. "At a time when these companies should be providing sanitizer, gloves, masks, and information about how to prevent the spread of the virus, they haven't been, because that would undermine their claim that these workers aren't their employees," said Benner. "Food and grocery delivery has been deemed essential work, and these workers are putting themselves at risk, but they are not getting adequate support or protection."

Assessing workers in the gig economy

The surge of app-based workers has raised questions about their well-being, their relationship to the companies they work for, and the future of the labor force. The baseline survey is among the most robust efforts to assess the circumstances of ride-hailing and grocery and meal-delivery workers.

"A survey like this is extremely rare, because it's expensive and labor-intensive," said Benner. "We paid the surveyors and the cost of the ride and meal, regardless of whether the worker was willing to participate in the survey." Benner acknowledged support from the San Francisco Foundation, ReWork the Bay, the Ford Foundation, the Annie E. Casey Foundation, Chavez Family Foundation, and SF LAFCo.

The survey was administered by UC Santa Cruz in partnership with San Francisco Jobs With Justice, Jobs With Justice Education Fund, and the Driver's Seat Cooperative. SF LAFCo commissioned the research. "This is a true example of community-engaged scholarship," said Benner.

Debates around the Green New Deal have largely centered around climate change concerns on land. But a group of scientists are calling on policymakers to include oceans in the deal.

The Green New Deal is a legislative proposal to tackle climate change and boost the economy, while also supporting equity and social justice.

"There is an opportunity to enact policy that can make meaningful change to help our country both economically and environmentally," said San Diego State University ecologist Rebecca Lewison, one of the co-authors of a new paper on the subject. "It's critical that oceans are part of that policy framework."

"Integrating Oceans into Climate Policy: Any Green New Deal Needs a Splash of Blue" was published in April in Conservation Letters. Lead authors are Lewison, whose work focuses on sustainable resource and land use, and Arielle Levine, an SDSU geographer specializing in human-environment interactions in marine and coastal systems, in collaboration with Oregon State University environmental economist Steven Dundas.

The authors recommend a policy that integrates terrestrial and ocean approaches to create a robust portfolio of climate adaptation and mitigation measures supporting communities, the environment and the economy.

"As we come out of this pandemic, policymakers will be looking for ways to jump start the economy, and we have a unique opportunity to develop policies that promote economic development in an environmentally sustainable manner," Levine said. "Including the oceans in Green New Deal policies will expand opportunities for sustainable economic development in both inland and coastal communities, while addressing the ongoing threat of climate change that we can't ignore."

Their proposals focus on renewable energy, sustainable transportation, food security and habitat restoration, and include:

Harnessing offshore energy

A push to expand offshore renewables will complement the push for renewable energy on land, the scientists said. As ocean winds pick up in the evening, they can supplement energy sources especially during the critical evening peak hours from 4 to 9 p.m.

"Developing offshore renewable energy will help states build a stronger, more adaptable and sustainable energy portfolio," Lewison said.

Reducing emissions from ships, freighters, ports

As with energy, climate-ready sustainable transport can and should include maritime shipping, since more than 80% of global merchandise travels by sea and ships are responsible for about 3% of greenhouse gas emissions.

Reducing ship speed is one measure that can reduce emissions. This will mean it takes ships longer to reach destinations, but it's a strategy shipping companies already use voluntarily when fuel prices are high.

"Policies to reduce speed, modifications to ship design and improved fuel efficiency standards for new ships can help significantly reduce emissions," Levine said. "Another way to reduce emissions is to have ships hook up to land-based energy sources while at port, which can also improve local air quality."

The European Union and the International Maritime Organization have set goals to reduce ship emissions by half by 2050. However, "the incentives need to be stronger, with specific targets along the way, to ensure this goal is met," Levine said.

Boosting food security

The oceans feed more people on the planet than any other source.

Sustainable wild-caught fish harvest paired with other approaches like aquaculture -- the process of 'farming' or growing seafood -- are needed to feed a hungry planet of 7.7 billion people. Aside from being a food source, cultivated seaweed can also help absorb carbon emissions.

"Properly executed aquaculture, paired with sustainable fisheries, has the potential to enhance food supply, decrease the carbon footprint of protein sources and sequester carbon at the same time," Dundas said.

To that end, the authors recommend more flexible, transboundary management structures that harness the best science and technology to meet global food demand, from seaweed to tuna.

Supporting sustainable fisheries and aquaculture does much more than support coastal economies. The food and money from seafood industries and markets support inland economies as well. New applications of ocean-based fertilizers can boost production on farms far from the coast, supplying nitrogen and phosphorus, which are necessary nutrients for agriculture but can be harmful when present in high concentrations in coastal waters.

Restoring wetlands, sea kelp, mangroves

When it comes to habitat restoration and climate change, replanting trees and forests are what come to mind most often. But the Teal Deal would also include restoration of wetlands, mangroves, seagrass and kelp, because coastal and ocean habitats need to stay intact to mitigate climate change, the paper notes.

"The perfect example is Hurricane Katrina -- one reason it was so devastating was that wetland and other coastal habitats have been lost to development," Lewison said.

A National Oceanic and Atmospheric Administration study found that each $1 million investment in wetland restoration creates an average of 17 jobs, in addition to providing a buffer for storm events.

"A Teal Deal combines land and ocean approaches to address climate change, generating economic benefits to communities everywhere," Lewison said. "The COVID-19 pandemic has shown us that rapid, responsive and coordinated efforts across sectors can stop a crisis. The climate change crisis is ongoing and an integrated policy offers the same opportunity -- to develop a responsive and coordinated multi-sectoral plan for climate resilience."

A team of scientists has taken steps to create a new form of digital data storage, a "Racetrack Memory," which opens the possibility to both bolster computer power and lead to the creation of smaller, faster, and more energy efficient computer memory technologies.

"Racetrack memory, which reconfigures magnetic fields in innovative ways, could supplant current methods of mass data storage, such as flash memory and disk drives, due to its improved density of information storage, faster operation, and lower energy use," says Yassine Quessab, a postdoctoral fellow at New York University's Center for Quantum Phenomena (CQP) and the lead author of the work, which is reported in the journal Scientific Reports.

"While additional development is necessary in order to deploy them in consumer electronics, this pioneering type of memory may soon become the next wave of mass data storage," adds NYU Physics Professor Andrew Kent, the paper's senior author.

Today's devices, from smart phones to laptops to cloud-based storage, rely on a remarkable and growing density of digital data storage. Because the need will only increase in the future, researchers have been seeking ways to improve storage technologies--enhancing their capacities and speed while diminishing their size.

The breakthrough reported in Scientific Reports, which also included researchers from the University of Virginia, the University of California, San Diego, the University of Colorado, and the National Institute of Standards and Technology, stemmed from a goal to develop a new format of digital memory.

The team's focus was on "a skyrmion racetrack memory," an undeveloped type of memory that reverses the processes of existing storage.

Many current mass data storage platforms function like an old musical cassette tape, which reads data by moving material (i.e., the tape) with a motor across a reader (i.e., in the cassette player), then decodes the information written on the material to reproduce sound. By contrast, racetrack memory does the opposite: the material stays in place and the information itself is moved across the reader--without the need to move mechanical parts, such as a motor.

The information is carried by a magnetic object called a skyrmion that can be moved by applying an external stimulus, such as a current pulse. A skyrmion, a magnetic texture with a whirling spin configuration, spins as if curled up in a ball. This ball of spins represents a bit of information that can be moved quickly as well as created and erased with electrical pulses. Skyrmions can be very small and moved at high speed at a low energy cost, thus enabling faster, high-density, and more energy-efficient data storage.

However, there remain barriers to this form of data storage.

"We found that small skyrmions are only stable in very specific material environments, so identifying the ideal materials that can host skyrmions and the circumstances under which they are created is a first priority for making the technology applicable," observes Kent. "This has been the focus of our research thus far."

The researchers' tests indicated that magnetic materials which generate only small magnetic fields--materials known as ferrimagnets--are favorable for creating small skyrmions and moving them. They showed that magnetic interactions can be precisely controlled in these materials to favor the formation of skyrmions.

The advances are part of CQP's larger effort in the area of spintronics--how the "spin" of electron particles interact with magnetization. An understanding of these interactions can lead to new capacities to manipulate magnetic and electric fields.

Scientists have discovered a potential new treatment for a disease that causes severe dry eyes and dry mouth.

The study, led by researchers at RCSI University of Medicine and Health Sciences, is published in the current edition of Scientific Reports. The work was carried out in collaboration with the Royal Victoria Eye and Ear Hospital and the Cedars-Sinai Medical Centre.

Sjögren's Syndrome causes the patient's white blood cells to attack the body's tear and saliva glands, causing severe dry eyes and mouth. The dry and irritated eyes significantly impact their vision, day-to-day activities and quality of life.

The researchers compared samples from the eyes of patients with the disease to samples from healthy patients. They found that those with the disease had abnormal levels of a certain molecule that controls eye inflammation.

The molecule, microRNA-744, works like a switch, turning the production of cells on and off. The researchers found that high levels of this molecule caused uncontrolled amounts of inflammation from cells that destroy the glands and damage the surface of the eye.

In a laboratory setting, the researchers were able to reduce this molecule, which in turn reduced the levels of inflammation.

"This is a first step toward a potential new treatment, and much more pre-clinical testing is needed before we can develop it into something that is ready for patients. However, our research provides the opportunity to possibly treat the root cause of the disease rather than just the symptoms," said Dr Joan Ní Gabhann-Dromgoole, the study's co-author and lecturer at RCSI's School of Pharmacy and Biomolecular Sciences.

The researchers also found different levels of other microRNAs in patient cells compared to healthy controls. This could be used to help diagnose patients with Sjögren's Syndrome, for which there is currently no test.

The disease is most common between the ages of 40 and 60, with women nine times more likely to suffer from it than men. It is estimated to affect three to four percent of adults in Ireland.

Artificial intelligence (AI) may be an aid to interpreting ECG results, helping healthcare staff to diagnose diseases that affect the heart. Researchers at Uppsala University and heart specialists in Brazil have developed an AI that automatically diagnoses atrial fibrillation and five other common ECG abnormalities just as well as a cardiologist. The study has been published in Nature Communications.

An electrocardiogram (ECG) is a simple test that can be used to check the heart's rhythm and electrical activity. The results are shown on a graph that can reveal various conditions that affect the heart. The tool is routinely used in healthcare and each ECG needs to be interpreted manually by a cardiologist.

The new study demonstrates that an AI is capable of automatically diagnosing the abnormalities indicated by an ECG. The AI was initially trained on a database comprising over two million ECGs that had already been diagnosed manually. In this way, it can learn to recognise typical patterns for the six most common ECG abnormalities and then make a diagnosis of another patient with one of these conditions - with the same precision as a cardiologist.

The method is currently not ready for use in clinics and hospitals; however, the researchers believe that it offers great potential for improved cardiovascular care in low and middle-income countries where large parts of the population lack the same level of access to specialists who are able to interpret ECG results as we enjoy in Sweden.

"This is the first result of a collaboration that we have built up over the past two years. I have great confidence that in the future this type of deep collaboration between AI researchers and medical researchers will be able to create new knowledge that can help people enjoy a better quality of life," says Thomas Schon, professor of automatic control, who works in machine learning and AI at Uppsala University and was responsible for the technical part of the study.

The mathematical model (known as a deep artificial neural network) on which the study is based is a good example of the basic concept behind machine learning, where computers build their own model and then use it to learn to solve tasks based on collected data. The method differs from the classic method of working with a computer where the computer is manually programmed to perform a very specific task. The results for many problems have proved to be better when machine learning is used and the computer itself is allowed to identify patterns from gathered figures, texts, diagrams and images.

A consortium of scientists with expertise in big data research and epidemiology recently developed a COVID Symptom Tracker app aimed at rapidly collecting information to aid in the response to the ongoing COVID-19 pandemic. As reported in the journal Science, early use of the app by more than 2.5 million people in the U.S. and the U.K has generated valuable data about COVID-19 for physicians, scientists, and public officials to better fight the viral outbreak.

"The app collects daily information from individuals in the community about whether they feel well, and if not, their specific symptoms and if they have been tested for COVID-19," said senior author Andrew T. Chan, MD, PhD, Chief of the Clinical and Translational Epidemiology Unit at Massachusetts General Hospital (MGH) and Director of Cancer Epidemiology at the MGH Cancer Center. The app is designed to provide insights on where the COVID-19 hot spots are and new symptoms to look out for, and it may be useful as a planning tool to inform guidelines around self-isolation, identify regions in need of additional ventilators and expanded hospital capacity, and provide real-time data to prepare for future outbreaks.

The COVID Symptom Tracker was launched in the U.K. on March 24th and became available in the U.S. on March 29th. Since launch, it has been used by more than 3 million people.

"This work has led to the development of accurate models of COVID-19 infection rates in the absence of sufficient population testing," said Dr. Chan. "For example, the U.K. government has acted upon these estimates by providing advanced notice to local health authorities about when to expect a surge of cases." Researchers are also using results from the app to investigate risk factors for infection, as well as the effects of COVID-19 on patients' health.

Dr. Chan also pointed out that the app does not have any contact tracing function in contrast with software that is being rolled out in the future by some states in collaboration with Apple and Google. "Our app is designed to be entirely voluntary so that they can share information about how they are feeling in a way that safeguards their privacy."

The team is asking individuals, even those who are feeling well, to download the app and participate in this effort to provide critically valuable information related to COVID-19. The study was conducted by a team led by researchers at Massachusetts General Hospital (MGH), King's College London, and Zoe Global Ltd.

Individuals with an underactive bladder, for example following a spinal cord injury, often cannot sense bladder fullness or are unable to empty the bladder completely. This distressing symptom can seriously affect one's quality of life. A dysfunctional bladder may also lead to medical complications such as urinary tract infection, as well as physical discomfort and potential for personal embarrassment.

Dr Faezeh Arab Hassani, a researcher from the National University of Singapore (NUS), has recently invented a device that can monitor bladder volume in real time and effectively empty the bladder. This innovation may open up a new treatment option for patients with underactive bladders in the near future.

Dr Arab Hassani worked closely with researchers from the NUS Department of Electrical Engineering and Computer Engineering, the NUS Department of Biomedical Engineering, as well as lead collaborator Professor Takao Someya and his research team at the University of Tokyo, and took more than a year to develop the novel bladder system. This breakthrough was first reported in the journal Science Advances on 1 May 2020.

Soft solution for a weak bladder

Among patients who have some form of spinal cord injury, about 80 per cent of them suffer from some degree of bladder dysfunction. There is currently no cure for the underactive bladder condition, and while some implantable treatment options are available, they can only sense the fullness of the bladder and only empty it up to 43 per cent.

"To help these patients, what clinicians need is an integrated bladder system that achieves both volume sensing capability and high voiding efficiency. Given that the urinary bladder is unique among human organs as it undergoes large volume changes during the storage and urination phases, the device requires careful compatibility considerations to avoid interference with the extreme volume changes of the bladder," said Professor Nitish Thakor, who supervised the research.

Dr Arab Hassani's novel system comprises a sensor integrated with an actuator. The soft and thin sensor monitors the bladder volume continuously while the actuator is equipped with strong emptying force to clear the bladder. The actuator contains a shape memory alloy (SMA) spring, which keeps the sensor in contact with the surface of the bladder at all times for precise volume detection.

Experiments by the team showed that in addition to the real-time volume sensing capability, the device can also effectively empty between 70 to 100 per cent of the bladder. "This is a significant achievement as its performance is comparable to the efficiency of intermittent catheterisation treatment currently being used, which has many shortcomings," shared Dr Arab Hassani, the first author of this study. "We need a soft but efficient device to help a weak bladder."

Improvements and potential applications

Moving forward, the NUS research team is working to improve the functionality of the device, and looking into making the system wireless for ease of use and movement.

"The bladder system can be adjusted to the user's bladder size to ensure optimal operation," suggested Dr Arab Hassani. "The ideal scenario would be to integrate the device with a mobile application, which can retrieve and process the sensor data to allow the user to trigger voiding at will."

The team's advances in soft materials and their fabrication techniques also hold other potential applications in the medical field.

"Our soft system demonstrated on a bladder can serve as a model for augmenting other organs as well," elaborated Prof Thakor. "I believe this novel design can pave the way for the development of sensors and actuators that are compatible with other soft and distensible organs like blood vessels, the heart, and the gastrointestinal system, as these organs require both sensing and actuation to achieve functions like pumping and peristalsis under soft actuation and control."

Expansions by groups of humans were common during prehistoric times, after the adoption of agriculture. Among other factors, this is due to population growth of farmers which was greater than of that hunter-gatherers. We can find one example of this during the Neolithic period, when farming was introduced to Europe by migrations from the Middle East.

However, in South America, it was not clear whether the same would have occurred as it was argued that no cultural group had expanded across such long distances as in Europe or Asia. In addition, it was believed that the type of agriculture practised by pre-Columbian peoples in the Amazon would not allow them to expand at the same rate.

Research conducted by three members of the Culture and Socio-Ecological Dynamics Research Group (CaSEs) at the UPF Department of Humanities shows that expansions by some archaeological cultures in South America can be simulated by computer through population growth and migration in the same way as the Neolithic in Europe. This is the case of so-called Saladoid-Barrancoid culture, which spread from the Orinoco to various parts of Amazonia, even reaching the Caribbean.

The article, published on 27 April in the journal PLOS ONE, involved Jonas Gregorio de Souza, a Marie Curie researcher, as first author, together with Jonas Alcaina Mateos, a predoctoral researcher, and Marco Madella, UPF-ICREA research professor and director of the CaSEs Research Group.

"The use of computer simulations to test human migrations in prehistoric times is an approach that has proved productive in other continents, but had not been applied to the area of the tropics of South America. We have shown that some cultural expansions that have taken place from Amazonia may be the result of similar demographic processes to the Neolithic in Eurasia", says Jonas Gregorio de Souza.

A computational model to simulate the expansions of four archaeological cultures

The article uses a computational approach to simulate human expansions in prehistory. "We use parameters derived from the ethnography of farmers in the Amazon to simulate the rate of population growth, the fission of villages, how far and how often they moved", the authors state. Based on these parameters, they created a computer model to simulate expansions from different points and dates and compare the results with archaeological data.

The researchers used radiocarbon dates from different archaeological cultures over a large area of territory in the last 5,000 years, which were compared with the prediction of the model, to assess whether their rate of territorial expansion could be explained as being a demographic phenomenon (rather than another type, such as cultural diffusion).

The four archaeological cultures or traditions analysed were the Saladoid-Barrancoid, the Arauquinoid, the Tupiguarani, and the (closely related) Una, Itararé and Aratu traditions. In most regions where they settled, these cultures introduced the cultivation of domesticated plants, marked the transition towards more permanent settlements, and spread an economic model called "polycultureagroforestry".

However, the authors warn that some expansions could not be predicted by the simulations, suggesting that they were caused by other factors: "Although some archaeological expansions can be predicted, by the simulations, as demographic processes, others are not easily explained in the same way. This is possibly due to different processes that drive their dispersal, such as cultural diffusion, or because the archaeological data are inconclusive or sparse", they conclude.

Senior Research Associate Margarita Sharina (Special Astrophysical Observatory) and Associate Professor Vladislav Shimansky (Kazan Federal University) studied the globular cluster NGC 6652.4.05957 and found out that its age is close to 13.6 billion years, which makes it one of the oldest objects in the Milky Way.

Globular clusters are mostly situated tens and hundreds of thousands of light years from Earth, and only the brightest stars in them can actually be studied. Margarita Sharina, a Kazan Federal University alumna, came up with the idea of researching the spectra of full star clusters several years ago. Together with Vladislav Shimansky, she developed Cluster, a special software package to model such spectra. During their joint work, the two scientists have determined fundamental characteristics of almost 40 globular clusters.

In this paper, they analyzed the spectra of NGC 6652 obtained by the Cerro Tololo Observatory. The overall ratio of heavy elements in the cluster turned out to be unusually high. Furthermore, some anomalies in the ratio of several elements (carbon, nitrogen, sodium, magnesium, calcium, and titanium).

"For a long time, the consensus was that the younger the galactic object is, the higher its metallicity. Closer to the late 20th century, astronomers started to move away from this viewpoint," explains Shimansky. "NGC 6652 is a rather old globular cluster, its age is about 13.6 billion years, according to various estimates. At the same time, its metallicity is rather high. The reason, hypothetically, is its unusual dynamics - the matter which formed the cluster has passed through the galactic disk multiple times and amassed the heavy elements synthesized there."

Studying globular clusters with up to a million stars can help research the early stages of the Universe.

During this past decade, many large telescopes have been observing galactic and extragalactic globular clusters - natural laboratories which facilitate the studies of stars and galaxies. Many more interesting discoveries are to be made after more data is deciphered, concludes Shimansky.

Certain bacteria, including the dangerous nosocomial pathogen MRSA, can protect themselves from acidic conditions in our body and thus ensure their survival. Researchers at the Biozentrum of the University of Basel have now elucidated an important mechanism in this process. A transport protein involved in cell wall biosynthesis plays a key role, they report in the journal "Nature Structural & Molecular Biology".

Each year, thousands of patients in Swiss hospitals become infected with dangerous pathogens that can hardly be controlled with antibiotics. The methicillin-resistant bacterium Staphylococcus aureus, MRSA for short, is particularly feared among the multi-resistant nosocomial germs. It can cause severe wound, respiratory and urinary tract infections and life-threatening sepsis. This is aggravated by the fact that MRSA causes chronic infections.

The cell wall as a therapeutic target

The bacterial cell wall is a key target in the search for new antimicrobials, as only an intact cell wall can protect the pathogens from the host's immune defence and from antibiotics. In a recent study, scientists led by Prof. Camilo Perez from the University of Basel's Biozentrum have elucidated the structure and function of a flippase transporter involved in the synthesis of lipoteichoic acids in the pathogen MRSA. Lipoteichoic acids are important biopolymers that provide stability to the cell wall of Gram-positive bacteria, facilitate colonization of the host and contribute to repelling antibiotics.

Transport of an "anchor" molecule to its destination

The cell wall is a highly dynamic layer that surrounds the cell membrane and protects bacteria. Lipoteichoic acids are long-chain biopolymers that are embedded in the cell wall. However, they only remain in place because they are bound to an "anchor" molecule at the cell membrane. Without this "anchor", lipoteichoic acids are not able to provide stability to the cell wall. "Based on our structural and functional analyses, we have been able to show for the first time how the "anchor" arrives at its destination and how bacteria energize this process," explains Perez. By moving hydrogen ions across the cell membrane, the flippase transporter is flipping the "anchor" molecule from the inside of the bacterial membrane, the site of its synthesis, to the outside, the site of lipoteichoic acid production.

Survival strategy of Gram-positive bacteria

"The fact that the transport of hydrogen ions is coupled with the synthesis of lipoteichoic acid represents a major survival advantage for these bacteria," says Perez. "The niches in the human body, which are preferentially colonized by Staphylococcus aureus, usually have an acidic microclimate. This means that the concentration of hydrogen ions is higher in these niches. The bacteria withstand these acidic conditions by simply building up a thicker protective layer of lipoteichoic acids."

The researchers have also been able to show that Staphylococcus aureus lacking the flippase transporter display severe growth defects upon acidic stress. According to the researchers, the flippase is essential for the survival of Staphylococcus aureus in our body and could be considered as a new pharmacological target for the treatment of dangerous MRSA infections.

Scientists have identified an unexpected player in the immune reaction gone awry that causes vision loss in patients with age-related macular degeneration (AMD), according to a new study published today in eLife.

The findings suggest that an immune-stimulating protein called interleukin-4 (IL-4) and its receptor may be promising targets for new drugs to treat AMD, a common form of age-related vision loss.

In patients with AMD, inflammation in the eye triggers excessive growth of new blood vessels in the center of the retina. This process damages the photoreceptors in the eye and leads to progressive vision loss. Normally, bone marrow cells help the body repair damaged tissues, while IL-4 helps suppress excessive blood vessel growth. Co-first author Takashi Baba, Junior Associate Professor in the Division of Ophthalmology and Visual Science at Tottori University, Japan, and his colleagues decided to look at whether these players might be helpful in patients with AMD. "The purpose of our study was to determine whether bone marrow cells and IL-4 protect the photoreceptors from neurodegeneration in patients with AMD," Baba explains.

To do this, the team measured levels of IL-4 in the eyes of 234 patients with AMD and 104 older individuals undergoing surgery for cataracts. They found that those with AMD had higher levels of IL-4 than those undergoing surgery.

Next, they found that IL-4 was also elevated in mice with a condition that mimics AMD. To determine if IL-4 was helping or harming the animals, they administered them with IL-4 and found that it increased the excessive growth of blood vessels in the eye. An antibody that blocks IL-4 production reduced this blood-vessel growth. Mice with the AMD-like condition that were genetically engineered to lack IL-4 also had less blood-vessel growth.

"Our results show that IL-4 plays a crucial role in excessive blood-vessel growth by recruiting bone marrow cells that aid this growth to the lesion in the eye," Baba says.

"These results were surprising and suggest that normally helpful immune responses can instead cause more harm," adds co-first author Dai Miyazaki, Associate Professor at the Division of Ophthalmology and Visual Science, Tottori University. "As IL-4 plays a key disease-promoting role in AMD, it may serve as a target for new treatments to treat this condition."

ITHACA, N.Y. - Cornell University researchers studying the structure of the virus that causes COVID-19 have found a unique feature that could explain why it is so transmissible between people.

Researchers also note that, aside from primates, cats, ferrets and mink are the animal species apparently most susceptible to the human virus.

Gary Whittaker, professor of virology, is the senior author on the study, which identifies a structural loop in the SARS-CoV-2 spike protein, the area of the virus that facilitates entry into a cell, and a sequence of four amino acids in this loop that is different from other known human coronaviruses in this viral lineage.

An analysis of the lineage of SARS-CoV-2 showed it shared properties of the closely related SARS-CoV-1, which first appeared in humans in 2003 and is lethal but not highly contagious, and HCoV-HKU1, a highly transmissible but relatively benign human coronavirus. SARS-CoV-2 is both highly transmissible and lethal.

"It's got this strange combination of both properties," Whittaker said. "The prediction is that the loop is very important to transmissibility or stability, or both."

Whittaker said the researchers are focused on further study of this structural loop and the sequence of four amino acids.

Cats, ferrets and minks are also susceptible. In order to infect a cell, features of the spike protein must bind with a receptor on the host cell's surface, and cats have a receptor binding site that closely matches that of humans. To date, infections in cats appear to be mild and infrequent, and there is not evidence that cats can, in turn, infect humans.

Whittaker added that investigations into feline coronaviruses could provide further clues into SARS-CoV-2 and coronaviruses in general.

Researchers from University of Nebraska and York University published a new paper in the Journal of Marketing that examines what can happen when "little guys" work together to pursue common interests.

The study forthcoming in the Journal of Marketing is titled "Collaborative Market Driving: How Peer Firms Can Develop Markets Through Collective Action" and is authored by Andre F. Maciel and Eileen Fischer.

In most established industries, large companies are dominant: Think of the technology, foods and beverages, entertainment, and banking sectors, for example. However, in some industries this dominance is effectively challenged by small and medium firms that carve out vibrant niches and build substantial customer bases in categories such as craft beer, specialty coffee, community-supported agriculture, and credit unions.

The researchers identify the backstage work through which small and medium-sized businesses can increase their political and economic clout. Specifically, they reveal the importance of collective action, identifying a strategy referred to as "collaborative market driving." Maciel says that "We identify how firm owners form a strong sense of shared identity and pool their resources to jointly develop a market category in ways that benefit all of them. Their collective work ranges from exchanging critical economic resources to fighting together for more favorable regulation."

The study also analyzes the key role trade associations can play as coordinators of this form of collective firm action. Trade associations can offer inspiring templates for how smaller firms should relate to each other and make sense of their competitive environment. Further, consumers can play key role as allies of these firms by providing some of the resources that they may lack to develop a market category.

For the most part, marketing researchers have focused on evolution powered by individual firms that cooperate with members of their supply chain, but compete fiercely with their peers. By contrast, this research brings into focus the role of collective action among peer firms. Fischer adds, "These firms follow the motto 'a rising tide floats all boats' and find ways to manage their own interests while working toward the interests of their collective."

Perhaps most importantly, the findings suggest a viable course of action for entrepreneurs interested in developing new market categories when they lack adequate resources to do so individually. By acting in concert, they can become a force to be reckoned with, enacting a marketplace version of the parable of David and Goliath.

Full article and author contact information available at: https://doi.org/10.1177/0022242920917982