Endangered vaquita remain genetically healthy even in low numbers, new analysis shows

Study found no sign of inbreeding or 'extinction vortex' often linked to small populations

NOAA FISHERIES WEST COAST REGION

Research News

 

IMAGE: THE FIRST VAQUITA CAUGHT AS PART OF A CONSERVATION EFFORT IN 2017. view more 

CREDIT: VAQUITA CPR

The critically endangered vaquita has survived in low numbers in its native Gulf of California for hundreds of thousands of years, a new genetic analysis has found. The study found little sign of inbreeding or other risks often associated with small populations.

Gillnet fisheries have entangled and killed thousands of vaquitas in recent years and scientists believe that fewer than 20 of the small porpoises survive today. The new analysis demonstrates that the species' small numbers do not doom it to extinction, however, and so gives hope for the small remaining population. Vaquitas have long survived and even thrived without falling into an "extinction vortex," the new study showed. That's a scenario in which their limited genetic diversity makes it impossible to recover.

"The species, even now, is probably capable of surviving," said Phil Morin, research geneticist at NOAA Fisheries' Southwest Fisheries Science Center and lead author of the new study published this week in Molecular Ecology Resources. "We can now see that genetic factors are not its downfall. There's a very good chance it could recover fully if we can get the nets out of the water."

Small but Stable Populations

An increasing number of species in addition to the vaquita have maintained small but stable populations for long periods without suffering from inbreeding depression. Other species include the narwhal, mountain gorilla, and native foxes in California's Channel Islands. Long periods of small population sizes may have given them time to purge harmful mutations that might otherwise jeopardize the health of their populations.

"It's appearing to be more common than we thought that species can survive at low numbers over long periods," said Morin, who credited the vaquita findings to genetic experts around the world who contributed to the research.

The idea that vaquitas could sustain themselves in low numbers is not new. Some scientists suspected that more than 20 years ago. Now advanced genetic tools that have emerged with the rapidly increasing power of new computer technology helped them prove the point.

"They've survived like this for at least 250,000 years," said Barbara Taylor, research scientist at the Southwest Fisheries Science Center. "Knowing that gives us a lot more confidence that, in the immediate future, genetic issues are the least of our concerns."

Sequencing the Vaquita Genome

The new analysis examined living tissue from a vaquita captured as part of a last-ditch international 2017 effort to save the fast-disappearing species. The female vaquita tragically died, but its living cells revealed the most complete and high-quality genome sequence of any dolphin, porpoise, or whale to date, generated in collaboration with the Vertebrate Genomes Project. Sequencing was led by Olivier Fedrigo, Jacquelyn Mountcastle, and Erich Jarvis at the Rockefeller University. "We felt it our moral duty to generate a high-quality reference of this species on the brink of extinction", said Jarvis. Only in recent years have advances in sequencing technologies and high-powered computers made such detailed reconstruction possible.

While the vaquita genome is not diverse, the animals are healthy. The most recent field effort in fall 2019 spotted about nine individuals, including three calves, within their core habitat. The robust calves suggest that inbreeding depression is not harming the health of these last vaquita. "These examples and others indicate that, contrary to the paradigm of an 'extinction vortex' that may doom species with low diversity, some species have persisted with low genomic diversity and small population size," scientists wrote in the new study.

The genetic data suggest that the vaquita's isolated habitat in the far northern Gulf of California has sustained roughly 5,000 vaquitas for around 250,000 years. The advent of gillnetting for fish and shrimp only a few decades ago drove vaquitas towards extinction, as they are incidentally caught in the nets.

More recently, Illegal gillnetting for totoaba, a fish about the same size and found in the same habitat as the vaquita, has compounded the losses. The practice has caused a catastrophic decline that is estimated as cutting the remaining population in half each year.

"Small numbers do not necessarily mean the end of a species, if they have the protection they need," Taylor said. "In conservation biology, we're always looking for risk. We shouldn't be so pessimistic. The sight of those three healthy calves in the water with their survivor mothers should inspire the protection they need to truly recover."

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FOR MORE INFORMATION

Cetacean Genomes Project

VaquitaCPR

Marine biology -- Sponges as biomonitors of micropollution

LUDWIG-MAXIMILIANS-UNIVERSITÄT MÜNCHEN

Research News

 

Sponges are filter feeders that live on particulate matter - but they can also ingest microscopic fragments of plastics and other pollutants of anthropogenic origin. They can therefore serve as useful bioindicators of the health of marine ecosystems.

Pollution of the world's oceans owing to anthropogenic input of plastics and other industrial wastes represents an increasing threat to the viability of marine ecosystems. - And because such pollutants accumulate in fish, crustaceans and mollusks, they enter the food chain and can be ingested by human consumers. Microparticles with dimensions of less than 5 mm present a particularly insidious problem. This class of pollutants includes microplastics and textile fibers, as well as synthetic chemicals found in consumer products such as household cleansers and cosmetics. It is therefore imperative to develop methods for quantifying the magnitude of the threat in order to develop effective measures to mitigate it. In a new publication in the journal Environmental Pollution, a research team led by Ludwig-Maximilians-Universitaet (LMU) in Munich Professor Gert Wörheide (Department of Earth and Environmental Sciences, and GeoBio-Center) shows that marine sponges have great potential as bioindicators for the monitoring of microscopic pollutants in the seas.

Sponges are sometimes referred to as the ocean's vacuum cleaners. They feed on tiny particles suspended in the currents, by filtering them from the seawater that passes through their highly porous tissues - which are supported by mineralized skeletons in many species. To assess their utility as bioindicators for microparticulate pollutants, Wörheide and colleagues studied 15 samples of a type of mineralized sponges belonging to the class known as 'demosponges' from a coral reef off the coast of the island of Bangka in Northern Sulawesi (Indonesia). "We chose this site because Southeast Asia is a hotspot for plastic pollutants in the oceans", says Elsa B. Girard, lead author of the study. Girard recently graduated from the Master's Program in Geobiology and Paleobiology at LMU, and her contribution to the paper was part of her Master's thesis. "In light of the impact of global warming, and the overexploitation of marine resources, local sponge species could act as useful biomonitors of micropollutants, and help us to develop appropriate measures to reduce the deleterious effects of these substances on reef communities", she explains.

In cooperation with specialists from the SNSB- Mineralogical State Collection in Munich and LMU's Department of Chemistry and Center for Nanoscience (CeNS), the biologists used two innovative methods to examine the samples collected from the reef. With the aid of two-photon excitation microscopy (TPE), they confirmed that sponges indeed incorporate microparticles into their tissues. Then they used Raman spectroscopy to characterize the nature of the particles themselves. The data obtained with the second technique revealed the presence of no less than 34 different types of microparticles in sponge tissues. The spectrum ranged from plastics such as polystyrene to cotton and titanium dioxide (TiO2). TiO2 is used in dyes and paints, as well as being a component of sunscreen lotions. Furthermore, the variation in the composition of microparticles in the different samples appears to reflect spatial variations in particle type in the surrounding water.

The researchers detected between 90 and 600 particles per gram of dried tissue in their sponge samples.  "Since sponges can weigh up to several hundred grams, we estimate on the basis of these results that each can accumulate more than 10,000 particles", says Wörheide. "This makes them promising candidates for the task of monitoring the levels of anthropogenic microparticle pollution in the oceans." With the exception of mollusks, few other species have the properties required of marine bioindicators. According to the authors of the study, sponges have several other "qualifications" for the job. They are abundant and are continuously active as filter-feeders. Moreover, measurements of pollution levels can be carried out on tissue samples (biopsies) without affecting the viability of the organisms.

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Elkhorn coral actively fighting off diseases on reef, study finds

Findings showed coral has core immune response regardless of disease type

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE & ATMOSPHERIC SCIENCE

Research News

 

IMAGE: DISEASE TRANSMISSION. view more 

CREDIT: PHOTO: MARGARET MILLER, SECORE INTERNATIONAL

MIAMI--As the world enters a next wave of the ongoing COVID-19 pandemic, we are aware now more than ever of the importance of a healthy immune system to protect ourselves from disease. This is not only true for humans but corals too, which are in an ongoing battle to ward off deadly diseases spreading on a reef.

A new study led by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science looked at the immune system of elkhorn coral (Acropora palmata), an important reef-building coral in the Caribbean, to better understand its response to diseases such as white band disease and rapid tissue loss.

In the experiment, healthy corals were grafted to diseased ones. After one week, the corals were analyzed to study the coral's overall gene expression in response to disease, if they exhibited an immune response, and whether there were different signatures of gene expression for corals that didn't show signs of disease transmission. The researchers found that A. palmata has a core immune response to disease regardless of the type of disease, indicating that this particular coral species mounts an immune response to disease exposure despite differences in the disease type and virulence.

"Our results show that elkhorn coral is not immunocompromised but instead is actually actively trying to fight off disease," said Nikki Traylor-Knowles, an assistant professor of marine biology and ecology at the UM Rosenstiel School and senior author of the study. "This gives me hope that the corals are fighting back with their immune system."

Based upon these findings, the researchers suggest that corals that did not get disease may have tougher epithelia, a protective layer of cells covering external surfaces of their body. And, that the symbiotic dinoflagellate, Symbiodiniaceae, that live inside corals did not have differences in gene expression in response to disease, but over the course of the two-year study did develop differences.

Coral disease is considered one of the major causes of coral mortality and disease outbreaks are expected to increase in frequency and severity due to climate change and other man-made stressors. The Caribbean branching coral Acropora palmata which has already seen an 80 percent decrease on reefs primarily due to disease, which has resulted in them being classified as threatened under the US Endangered Species Act.

"These corals are keystone species for Florida reefs, so understanding that their immune systems are active is an important component that can be useful for protecting reefs," said Traylor-Knowles.

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The study, titled "Innate immune gene expression in Acropora palmata is consistent despite variance in yearly disease events," was published October 22, 2020 in the journal PLoS One. The study's coauthors include: Ben Young and Nikki Traylor-Knowles of the UM Rosenstiel School; Former UM student Xaymara Serrano from NOAA's Atlantic Oceanographic and Meteorological Laboratory; Stephanie Rosales from NOAA's Cooperative Institute for Marine and Atmospheric Studies; Margaret Miller from SECORE International and Dana Williams from NOAA's Southeast Fisheries Science Center.

Fipronil, a common insecticide, disrupts aquatic communities in the U.S.

COLORADO STATE UNIVERSITY

Research News

 

IMAGE: ECOLOGIST JANET MILLER COLLECTS ROCK TRAYS IN THE CACHE LA POUDRE RIVER IN COLORADO. view more 

CREDIT: PHOTO COURTESY OF JANET MILLER

The presence of insecticides in streams is increasingly a global concern, yet information on safe concentrations for aquatic ecosystems is sometimes sparse. In a new study led by Colorado State University's Janet Miller and researchers at the United States Geological Survey, the team found a common insecticide, fipronil, and related compounds were more toxic to stream communities than previous research has found.

The study, "Common insecticide disrupts aquatic communities: A mesocosm to field ecological risk assessment of fipronil and its degradates in U.S. streams," is published Oct. 23 in Science Advances.

Fipronil is used in the U.S. for insect control on pets, structures, yards and crops. Most of the streams where fipronil compounds were found to exceed toxic levels were in the relatively urbanized Southeast region.

Miller said the insecticide is likely affecting stream insects and impairing aquatic ecosystems across the country at lower levels than previously thought. In addition, fipronil degrades into new compounds, some of which this study found to be more toxic than fipronil itself.

The research team also found delayed or altered timing of when these insects emerged from streams, which has implications for the connections between stream and land-based communities.

"The emerging insects serve as an important food source," Miller explained. "When we see changes, including a drop in emergence rates or delayed emergence, it's worrisome. The effects can reverberate beyond the banks of the stream."

In experimental settings that had a high concentration of fipronil, the researchers also saw a reduced number of insects that scrape or eat algae off the rocks, leading to an increase of algae in those streams.

Mimicking natural habitats

In this study, the research team studied the effects of fipronil compounds on aquatic macroinvertebrates, insects that live on the rocks and sediment of stream bottoms. Examples of these insects include mayflies, stoneflies and caddisflies. These creatures spend the larval life stage in streams as aquatic invertebrates, later emerging from streams as flying insects.

"These macroinvertebrates serve as an important food source for fish and other organisms while also playing an important role in nutrient cycling ," said Miller, an aquatic ecologist with the Colorado Natural Heritage Program, which is part of the Warner College of Natural Resources at Colorado State University.

As one part of the study, the research team built rock trays to mimic the invertebrate's habitat, and placed them in the Cache La Poudre River in northern Colorado. In these habitats, the macroinvertebrates colonized naturally with algae to mimic communities that exist in nature.

Next, the scientists moved the rock trays containing macroinvertebrates into the lab, mimicking a natural environment while also controlling temperature, light and water flow. The team then added a range of concentrations of the insecticide fipronil or one of four associated fipronil degradate compounds - sulfone, sulfide, desulfinyl and amide - and observed the effects on macroinvertebrates.

Scientists found these degradates to be as toxic, if not more so than fipronil. Yet Miller said there is generally a lack of data for the compounds.

Streams in southeast most affected by fipronil

As an additional prong of the research, Miller and the team applied results from the laboratory experiment to data from a large field study conducted by the United States Geological Survey that sampled streams across the U.S. in five major regions.

Miller said fipronil compounds were detected at unsafe concentrations in 16% of streams sampled across the U.S. and were most prevalent in streams of the Southeast region of the country. Scientists found fipronil compounds much less widespread in other regions, suggesting use patterns of the insecticide differ across the country.

"We found that 51% of sampled streams in the southeast revealed the presence of fipronil, while in the Pacific Northwest, we detected only around 9% of streams with the insecticide," she said.

Miller said that while the results are concerning, it's helpful to have this scientific-based evidence to share with the scientific community and regulating agencies.

"We hope our findings provide greater understanding of the prevalence of fipronil compounds across the country and the levels at which these compounds are harmful to stream health," she said.

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Fish exposed to even small amounts of estrogen produce fewer males

UC biologist is studying water quality downstream of sewage treatment plants

UNIVERSITY OF CINCINNATI

Research News

 

IMAGE: UC IS USING LEAST KILLIFISH AS A MODEL ORGANISM TO STUDY THE EFFECTS OF HORMONES IN DRINKING WATER. THEY ARE AMONG THE SMALLEST VERTEBRATES ON EARTH. view more 

CREDIT: ANDREW HIGLEY/UC CREATIVE

Water tainted with even a small concentration of human hormones can have profound effects on fish, according to a University of Cincinnati biologist.

UC assistant professor Latonya Jackson conducted experiments with North American freshwater fish called least killifish. She found that fish exposed to estrogen in concentrations of 5 nanograms per liter in controlled lab conditions had fewer males and produced fewer offspring.

Scientists have found estrogen at as much as 16 times that concentration in streams adjacent to sewage treatment plants.

The study suggests that even this small dose of estrogen could have significant consequences for wild fish populations living downstream from sewage treatment plants.

The study was published this week in the journal Aquatic Toxicology.

What's special about least killifish is they have a placenta and give birth to live young, Jackson said. It's uncommon among fish, who more typically lay eggs.

Jackson studied a synthetic estrogen called 17α-ethinylestradiol, an active ingredient in oral contraceptives also used in hormone replacement therapy. Estrogen been found in streams adjacent to sewage treatment plants in concentrations of as high as 60 nanograms or more per liter.

"Anything you flush down the toilet or put in the sink will get in the water supply," she said. 

This includes not only medicine people flush (never do that) but also unmetabolized chemicals that get flushed when people use the bathroom.

"Our wastewater treatment systems are good at removing a lot of things, but they weren't designed to remove pharmaceuticals," Jackson said. "So when women on birth control or hormone therapy go to the bathroom, it gets flushed into wastewater treatment plants."

Chronic exposure of fish to estrogen led to smaller populations and a gender ratio imbalance with more females than males.

Now Jackson wants to know how the exposure to hormones such as estrogen and androgen in a female fish affects her offspring. She is collaborating with the U.S. Environmental Protection Agency to examine local waters in southwestern Ohio.

Jackson said the impacts on streams are not limited to fish. Hormones and other chemicals that are not removed during treatment can bioaccumulate in the food chain or end up in our drinking water.

"Our drinking water is not a renewable resource. When we run out of clean drinking water, it's gone," Jackson said. "It's very important that we keep this resource clean."

Coastal permafrost more susceptible to climate change than previously thought

UNIVERSITY OF TEXAS AT AUSTIN

Research News

 

IMAGE: MICAELA PEDRAZAS (LEFT) AND CANSU DEMIR, BOTH GRADUATE STUDENTS AT THE UNIVERSITY OF TEXAS AT AUSTIN JACKSON SCHOOL OF GEOSCIENCES, EXAMINING AN EXPOSED SIDE OF AN ICE WEDGE POLYGON, WHICH... view more 

CREDIT: BAYANI CARDENAS

If you flew from the sea towards the land in the north slope of Alaska, you would cross from the water, over a narrow beach, and then to the tundra. From the air, that tundra would look like a landscape of room-sized polygonal shapes. Those shapes are the surface manifestations of the ice in the frozen ground below, a solidified earth known as permafrost.

Scientists long believed the solid permafrost extended offshore: from the tundra, below that narrow beach and below the seafloor declining at a gentle slope. They viewed that permafrost like solid brick, locking the subsurface--and the vast amounts of carbon it holds--in place.

But new research led by Micaela Pedrazas, who earned her masters at The University of Texas at Austin Jackson School of Geosciences working with Professor Bayani Cardenas, has upended that paradigm. They found permafrost to be mostly absent throughout the shallow seafloor along a coastal field site in northeastern Alaska. That means carbon can be released from coastline sources much more easily than previously thought.

The study was published in Science Advances on Oct. 23 with coauthors from the Jackson School and UT's Marine Science Institute.

Using a geophysical technique called electrical resistivity imaging, the researchers mapped the subsurface beneath Kaktovik Lagoon along the northeastern coast of Alaska over the course of three years.

The results were unexpected. The beach and seafloor were entirely ice-free down to at least 65 feet. On the tundra itself, ice-rich permafrost was detected in the top 16 feet, but below that, the subsurface their imaging mapped was also ice-free.

"This leads to a new conceptual model," Pedrazas said.

Permafrost is found in cold climates that remain frozen during the course of the year. Scientists have been tracking the impact of a warming climate on permafrost because as it melts, permafrost releases its stores of frozen carbon into the atmosphere as methane and carbon dioxide, contributing to climate change.

Permafrost studies have almost exclusively focused on the region beneath the tundra. Because it's not easy to work in such remote locations and under harsh weather conditions, the transition from sea to shore has been largely ignored.

"This study tells us that the coastline is much more complicated than we thought," said co-author Jim McClelland from UT's Marine Science Institute. "It opens up the possibility for routes of water exchange that we weren't thinking about."

Besides global considerations, the work has local impacts. The communities along the coast, most of whom are Inupiat, live on the permafrost. As the permafrost thaws, it accelerates coastal erosion, which carves away at the land on which homes and infrastructure stand. In the Kaktovik region, erosion can be as great as 13 feet per year.

"Their cultural heritage and their welfare is integrated and intricately linked to their environment," Cardenas said. "There's an immediate need to understand what's happening in these lagoons."

The new paradigm requires reimagining the coastal Arctic ecosystem as well. Liquid groundwater means that carbon and nutrients can move between the tundra and the lagoon. It also means that saltwater can move beneath the tundra, potentially affecting freshwater sources.

Paul Overduin, who wasn't involved in the research, but who studies permafrost at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, said that this work is the first step in understanding permafrost's transition from sea to shore.

"As is often the case, when we start looking at something people don't know much about, you open up a whole bunch of questions that needed to be looked at," he said. "That's what's really exciting here."

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The research was funded by the Geology Foundation at The University of Texas at Austin and the National Science Foundation through the Beaufort Lagoon Ecosystems LTER, the Geological Society of America and the Ivanhoe Foundation. The Kaktovik Inupiat Corporation and the U. S. Fish and Wildlife Service also provided permissions and support.

The hidden threat of the home office

Yes, there are benefits to working at home; but there are traps, too

NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Research News

 

 

It may seem a bit contradictory at first glance, but increased flexibility in our workday may have given us less flexibility in the work itself.

The daily press and the nascent research literature on COVID-19 speculate on the long-term consequences of the coronavirus situation. These could change the way we think about the methods we employ in our working life, especially with regard to home offices and digital collaboration.

Several large companies, both internationally and nationally, have announced that they plan to continue the option of working from home for anyone who also wishes after the pandemic. The arguments for this include:

Greater flexibility in organizing work and family life situations seems to significantly reduce stress for many people.

Time that was previously used for commuting or travelling between meetings can now be used for other things, which in turn may lead to higher productivity.

One common argument is that a home office situation provides fewer distractions and can make us more efficient.

Employers, for their part, see an opportunity for reduced travel costs and less need for office space.

Working from home is also happening in academia, and several universities have said that the home office option will continue.

On the other hand, it has been pointed out that people cannot work exclusively in physically separate environments. We need opportunities to meet with colleagues and experience the social cohesion and replenishment this provides.

The consequences of this kind of distributed work situation for workplace practices constitute an important aspect that has received less attention so far. How does working from home affect collaborative efforts and the quality of work, both in smaller teams and in larger work communities?

The article "Learning of academics in the time of the Coronavirus pandemic," describes how academic practices changed, quite significantly, under the conditions we have worked under since March.

One conclusions is that we cannot expect work practices to remain the same when we move them. As conditions change around practices, so do the practices themselves.

In two parallel projects, an international coalition of researchers led by the Norwegian University of Science and Technology (NTNU) collected data from students and academic staff. They focused on their work and study situations during the corona pandemic.

The data includes 1600 students and 16 lecturers in a course called Experts in Teamwork offered at NTNU. Students provided feedback through questionnaires, written exam reports and in-depth interviews. The lecturers represented different faculties and departments and were also interviewed in depth.

The preliminary findings show great variations in the consequences that the new work and study situations have had for individuals and for groups.

Some people became more efficient in their new work setting, for example because they had fewer distractions and work became easier to prioritize. But others became less efficient, for example due to lower motivation and lack of daily structure.

Some individuals thought it was beneficial to have more peace and flexibility in their daily life, while others felt lonelier and less motivated due to the lack of social and physical contact with fellow students and colleagues.

A number of the academic staff also had a much busier schedule due to home schooling their children. This factor is less relevant in a situation without a pandemic.

The study also found many of the positive elements of distributed teamwork and working digitally that are mentioned at the beginning of our article.

However, one finding stands out as a paradox.

While working from a home office, or as a distributed team, provides significantly increased flexibility for the work situation, it could provide less flexibility in carrying out the work, both in terms of meeting colleagues, collaborating and teaching.

This flexibility issue, or paradox, is largely related to a much greater need for structure, planning and clear communication in the digital modality. Meetings and teaching need to be planned in much more detail, and the digital form makes it difficult to deviate from the plan.

We lose the ability to pick up cues from the room, like we do when we are in a physical space together. Several communication-related aspects of working digitally also make it difficult to achieve a good flow, as well as to make spontaneous and necessary changes.

The researchers also found that the threshold for making small and necessary clarifications with collaborators is significantly higher in the digital realm. The flexibility to complete a task is therefore reduced and can affect the quality of what we do.

For example, people risk working alone with a task for too long, assuming rather than clarifying along the way. We don't want to disturb people, and we don't know what they are doing right now. Researchers found this to be the case both for students who worked synchronously, and for academics who mostly worked asynchronously.

Home offices may offer benefits for many, but it is hardly advantageous for everyone. More people will probably choose to work from home more than they did before, even when the pandemic has subsided. But having the opportunity to convene physically is still important, not only for each of us to meet our social needs, but also for the employer and for the quality of the work.

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Source: Learning of academics in the time of the Coronavirus pandemic. E. Sjølie, S. Francisco, K. Mahon, M. Kaukko, S. Kemmis - Journal of Praxis in Higher Education, 2020.

Knowing the model you can trust - the key to better decision-making

CRANFIELD UNIVERSITY

Research News

 

As much of Europe is engulfed by a second wave of Covid-19, and track and trace struggles to meet demand, modelling support tools are being increasingly used by policymakers to make key decisions. Most notably, models have been used to predict the Covid-19 R0 rate - the average rate of secondary infections from a single infection, which has formed the basis for many lockdown decisions across the UK.

Models can represent the most effective tool for identifying interventions that can balance the risks of widespread infection and help assess socio-economic disruption until an effective treatment is established. However, not all models are equal, and differences in model predictions during the Covid-19 pandemic have caused confusion and suspicion.

A recent paper 'Three questions to ask before using model outputs for decision support' published in Nature Communications aims to help decision makers choose the best available model for the problem at hand. The paper proposes three screening questions that can help critically evaluate models with respect to their purpose, organisation, and evidence, and enable more secure use of models for key decisions by policy makers.

One of the authors of the paper, Dr Alice Johnston, Lecturer in Environmental Data Science at Cranfield University, said: "From Covid-19 to the stock market, models are increasingly used by policymakers to support their decisions.

"However, different models are based on different assumptions and so can produce conflicting results, even when they represent the same system. Models used early on in the Covid-19 pandemic were a prime example of this, which led to confusion over which models to trust to support the decision-making process. This really highlights the need for clear communication of a model's context, so that policymakers have confidence in which models to trust.

"We propose that before engaging with a model, policymakers ask themselves three screening questions focusing on the model's purpose, organisation and evidence base, with the aim of bringing greater clarity to the decision-making process."

 

Residents of U.S. counties with more connections to China or Italy were more likely to follow early pandemic restrictions

Social connections with COVID-19-affected areas increase compliance with mobility restrictions

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

Research News

 

Residents of U.S. counties with more social connections (measured as Facebook friends) to China or Italy - the first countries to report major COVID-19 outbreaks - were more likely to adhere to social distancing restrictions at the onset of the pandemic, according to a new study. The findings suggest that social networks supplied pandemic-related information that significantly influenced individual behavior. However, social ties also could have negative effects on pandemic-related behavior. For instance, areas within the U.S. with more connections to counties with low education levels, high proportions of 2016 Trump voters, and high fractions of people who deny the existence of climate change experienced less adherence to mobility restrictions during the early pandemic. Previous research suggests online social connections may act as warning systems during natural disasters and can impact personal health decisions by spreading both facts and misinformation. To explore the role of these connections in the context of COVID-19-era social distancing, Ben Charoenwong and colleagues measured social connectedness between U.S. counties and foreign countries using aggregated, anonymized data from Facebook's Social Connectedness Index. The researchers combined this data with anonymized, county-level mobile phone location data that served as a proxy for adherence to social distancing measures between February 1 and March 30, 2020. They found that a one-standard-deviation increase in social connections with China or Italy correlated with a nearly 50% increase in the effectiveness of mobility restrictions. The authors also conclude that differences in how effectively Democrats and Republicans adhere to social distancing arise from discrepancies in the information they receive (facilitated by their social connections) rather than due to biases in how they interpret that information. "This finding has important policy implications, as it suggests changes in the information environment can boost the effectiveness of non-pharmaceutical interventions," the authors write.

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Study helps explain declines in death rates from COVID-19

NYU LANGONE HEALTH / NYU SCHOOL OF MEDICINE

Research News

 

Fewer New Yorkers are dying from the coronavirus than health experts had anticipated, a new study shows. Regional death rates have dropped from the highs seen at the start of the outbreak, partially due to a shift in the population contracting the disease toward those who are more resilient.

After New York became the epicenter for the pandemic in early March, with tens of thousands dying from COVID-19, experts had expected that the infection would remain as deadly in the following months.

Instead, a new investigation showed that by mid-August the death rate in those hospitalized with coronavirus-related illness had dropped from 27 percentage points to about 3 percentage points. Led by researchers at NYU Grossman School of Medicine, the study showed that a younger, healthier group of people were getting infected and were arriving at the hospital with less-severe symptoms than those infected in the spring.

However, the researchers' analysis showed that these factors accounted for only part of the improvement in survival. The rest, they suspect, resulted from health care providers' growing experience with the coronavirus. For example, physicians learned that resting COVID-19 patients on their stomachs rather than their backs and delaying the use of ventilators as long as possible were more effective practices, say the study authors. Drugs likely helped as well. In addition, other factors such as decreasing hospital volumes, less exposure to infection, and earlier testing and treatment, may have played a role.

"Our findings suggest that while COVID-19 remains a terrible disease, our efforts to improve treatment are probably working," says study lead author Leora Horwitz, MD, an associate professor in the Department of Population Health at NYU Langone Health. "Even in the absence of a silver-bullet treatment or vaccine, we are protecting more of our patients through a host of small changes," says Horwitz, who is also director of the Center for Healthcare Innovation and Delivery Science at NYU Langone.

New York was among the first states to grapple with a severe outbreak of COVID-19. By contrast, death rates in more recent waves in southern and western regions of the country, which also had younger, healthier coronavirus patients, have been lower, says Horwitz. However, it had remained unclear whether the virus was less deadly due to the different patient demographics or improved care.

Horwitz says the new study, publishing online next week in the Journal of Hospital Medicine, is the most detailed analysis to date of coronavirus death rates over time. By accounting for age, obesity, and other key factors, the researchers were able to eliminate some explanations from the analysis.

For the investigation, the research team analyzed 5,263 patient records of people treated for COVID-19 at NYU Langone hospitals in New York City and Long Island between March 1 and Aug. 8. Using a range of risk factors for the disease as well as indicators of the severity of the illness upon hospitalization, the study authors developed a model that predicted likelihood of death for each patient.

According to the findings, the likelihood of death was on average 22 percentage points lower in August than in March for most critically ill patients.

The average age of hospitalized COVID-19 patients also dropped from 63 to 47. In March, while 73 percent had chronic conditions like lung disease and diabetes, by mid-June only about 65 percent had such risk factors.

"Other pandemic hotspots should take hope from the lessons learned here in New York," says study senior author Christopher Petrilli, MD, an assistant professor in the Department of Medicine at NYU Langone. "If we can do better at managing the disease, they can too."

Still, he adds that the research team next plans to expand the investigation to hospitals outside of New York.

Petrilli also cautions that while death rates are improving, COVID-19 still causes symptoms in some people that continue long after hospital patients are sent home, including fatigue, blood clots, and lung damage.

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NYU Grossman School of Medicine provided all the necessary funding for the study.

In addition to Horwitz and Petrilli, other NYU Langone researchers include Simon Jones, PhD; Robert Cerfolio, MD; Fritz Francois, MD; Joseph Greco, MD; and Bret Rudy, MD.