Long-term data show a recent acceleration in chemical and physical changes in the ocean

Two open-ocean hydrographic stations record 40 years of change in the subtropical North Atlantic Ocean

BERMUDA INSTITUTE OF OCEAN SCIENCES

Research News

 

IMAGE: FROM L TO R: ROD JOHNSON (BATS CO-PI), EMILY DAVEY (RESEARCH TECHNICIAN), DOM SMITH (RESEARCH TECHNICIAN) AND CLAIRE MEDLEY (RESEARCH TECHNICIAN) SAMPLE THE CTD FOR DISSOLVED O2 AND CO2 ABOARD... view more 

CREDIT: ELLA CEDARHOLD, BERMUDA INSTITUTE OF OCEAN SCIENCES

New research published in Nature Communications Earth & Environment uses data from two sustained open-ocean hydrographic stations in the North Atlantic Ocean near Bermuda to demonstrate recent changes in ocean physics and chemistry since the 1980s. The study shows decadal variability and recent acceleration of surface warming, salinification, deoxygenation, and changes in carbon dioxide (CO2)-carbonate chemistry that drives ocean acidification.

The study utilized datasets from Hydrostation 'S' and the Bermuda Atlantic Time-series Study (BATS) projects at the Bermuda Institute of Ocean Sciences (BIOS). Both are led by Professor Nicholas Bates, BIOS senior scientist and the projects' principal investigator (PI), and Rod Johnson, BIOS assistant scientist and the projects' co-PI. Together, these time-series represent the two longest continuous records of data from the global open ocean.

"The four decades of data from BATS and Hydrostation 'S' show that the ocean is not changing uniformly over time and that the ocean carbon sink is not stable over recent time with variability from decade to decade," Bates said.

Of the two sites, Hydrostation 'S' is the oldest, located approximately 15 miles (25 km) southeast of Bermuda and consisting of repeat biweekly hydrographic observations of temperature, salinity, and dissolved oxygen conducted through the water column since 1954. The Bermuda Atlantic Time-series Study (BATS) site is located approximately 50 miles (80 km) southeast of Bermuda. It consists of monthly sampling of the physics, chemistry, and biology of the entire water column since 1988. The study's datasets represent more than 1381 cruises to Hydrostation 'S' from 1954 to 2020 and more than 450 cruises to BATS from 1988 to the end of 2019.

Results showed that, over the last 40 years, surface temperatures in the Sargasso Sea have increased by 0.85 +/- 0.12oC, with the summer surface temperatures rising at a higher rate than winter. Additionally, the winter (<22°C) ocean state has gotten shorter by almost a month, while the summer season (with waters warmer than 25°C) has gotten longer. During the same period, surface salinity also increased by ~0.11 +/- 0.02. Importantly, these data show evidence of decadal variability; however, during the last decade (2010-2019), rapid warming of 1.18oC and salinification of 0.14 has occurred.

The data also show a trend of dissolved oxygen (DO) decline in the Sargasso Sea since the 1980s, representing a loss of ~2% per decade. Given the ocean warming observed in the Sargasso Sea, the researchers estimate that the warming impact on DO solubility would likely have contributed to about 13% of the total decline of DO over the past nearly 40 years. The remaining deoxygenation (~87%) must have resulted from the combined effect of changes in ocean biology and physics.

The BATS and Hydrostation 'S' time-series data allow direct detection of the ocean acidification signal in the surface waters of the North Atlantic Ocean. The typical pH range of surface waters in the 1980s ranged from wintertime highs of ~8.2 to summertime lows of ~8.08-8.10, with the ocean remaining mildly alkaline at present (~7.98-8.05). The rate of pH change is ~0.0019 +/- 0.0001 year-1, which is a more negative rate than previously reported and represents a 20% increase in hydrogen ion concentration since 1983. These changes were accompanied with significant increases of dissolved inorganic carbon and CO2 and decreases in both calcite and aragonite saturation states.

"In forty years, seawater CO2-carbonate chemistry conditions are now altered beyond the seasonal chemical changes observed in the 1980s," Johnson said. "The modification of seawater CO2 -carbonate chemistry will continue with future anthropogenic CO2 emissions."

The observations off Bermuda reveal the substantial decadal variations and highlight the need for long-term data to determine trends in other ocean physical and biogeochemical properties, particularly when linking local measurements to basin-scale changes. Long-term data on ocean chemistry and physical from time-series sites such as Hydrostation 'S' and BATS provide critically needed and unparalleled observations that, when coupled with ocean-atmosphere models, allow for a more complete understanding of drivers of the global carbon cycle.

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RUDN University soil scientist: Paddy soil fertilization can help reduce greenhouse effect

RUDN UNIVERSITY

Research News

 

IMAGE: A SOIL SCIENTIST FROM RUDN UNIVERSITY DISCOVERED THE EFFECT OF FERTILIZATION ON THE ABILITY OF THE SOIL TO RETAIN CARBON. TO UNDERSTAND THIS MECHANISM, HE AND HIS TEAM STUDIED THE... view more 

CREDIT: RUDN UNIVERSITY

A soil scientist from RUDN University discovered the effect of fertilization on the ability of the soil to retain carbon. To understand this mechanism, he and his team studied the movement of organic carbon in the soil of rice paddies. The results of the study can help increase the fertility of the paddies while at the same time reducing the volume of greenhouse gases in the atmosphere. An article about the study was published in the Soil Biology and Biochemistry journal.

The main reason for global climate change is the increasing amount of carbon dioxide in the atmosphere. CO2 prevents thermal emissions from leaving our planet, and the so-called greenhouse effect occurs. Being able to absorb up to 10% of carbon dioxide from the atmosphere (which amounts to approximately 20,000 megatons of carbon in 25 years), soils could mitigate this effect. A soil scientist from RUDN University studied the mechanism of carbon retention in the soils of rice paddies that account for 40% of natural atmospheric carbon absorption in China. According to him, the ability of the soil to retain carbon depends, among other factors, on its structure and the presence of fertilizers.

"The soils of rice paddies play an important role in mitigating the consequences of global warming and contribute a lot to the retention of carbon. The most effective way to study the processes that lead to the accumulation of organic carbon in the soil is to measure the concentration of its isotopes. We used this method to find out how mineral and organic fertilizers affect carbon flows between fractions of different density in rice paddy soils," said Yakov Kuzyakov, the Head of the Center for Mathematical Modeling and Design of Sustainable Ecosystems at RUDN University.

The team studied three groups of soils with different types of fertilizers: azophoska, or nitrogen-phosphorus-potassium fertilizer, was added to the first group; the second one contained azophoska with straw, and the third--azophoska with organic supplements. The content of carbon in the soils and its movement between density fractions was determined based on the ratio of 13C and 12? isotopes. The second and the third group showed better carbon retention results: after fertilization, their carbon content grew by 69%, while the increase in the first group amounted to 30%.

The scientists also paid attention to the changes in soil structure under the influence of fertilizers and the effect of such changes on carbon retention. Fertilizers consolidate the structural elements of the soil, and the number of large soil particles (over 0.25 mm in diameter) grows. Soils of medium density showed the highest carbon retention efficiency after fertilization: the amount of accumulated carbon increased by 70% compared to unfertilized soils. Less dense soil fractions showed a 21-56% increase, and carbon retention in dust and clay grew by 24-49%.

"We confirmed that fertilizers support organic carbon retention in the soil. Knowing this, we could better understand the processes that lead to the accumulation of soil carbon in rice paddies. These agricultural ecosystems already play an important role in world food security and now can also help us combat climate change," addedYakov Kuzyakov.

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Trees prefer the big city life

Study finds that red maples were more productive in an environment with more urbanization

UNIVERSITY OF DELAWARE

Research News

A team of researchers have examined whether urban red maples - a resilient native tree known to thrive in urban environments - acclimate to environmental shifts and whether that response is impacted by the size of the city.

They found that trees in larger cities are actually healthier and more productive than those in less dense areas.

To determine how trees respond to different urban intensities, the team - which includes researchers from the University of Delaware - compared forests in Newark, Del., to those in Philadelphia, Pa. In forest fragments that make up the FRAME network in each city, data was collected to measure tree size and age, foliage nitrogen signature, nutrient and heavy metal content, and stress-responding metabolites, as well as surrounding soil conditions.

Not only were the trees acclimated to urban conditions but the red maples in the higher density Philadelphia forests were actually healthier and more productive than those surrounded by less urbanization in Newark.

"We have different levels of nitrogen deposition due to fumes from vehicle tailpipes, construction materials are adding excess calcium into forest soils, carbon dioxide levels are elevated because of population density, and we have impervious surfaces like roads and buildings that are holding heat and warming up the city in a phenomenon we call urban heat island," said Covel McDermot, a University of Delaware alumnus and co-author of the study. "Our goal was to evaluate health and stress-indicating compounds in the leaves of red maple trees that face these conditions in forests embedded in a large, heavily urbanized city versus a small, fairly urbanized city."

People usually think that urban ecosystems are nutrient deficient, but we see that these systems have higher nutrient loads that support productivity.

For example, in Philadelphia there is a lot of construction using concrete. Concrete is a substance that contains calcium, magnesium and aluminum. As construction and deconstruction happen, as they often do in cities, these materials eventually break down and become available food sources for plants. Look at your wall. It's likely made of materials containing gypsum and those will eventually end up in the soil and become bioavailable to plants.

To build barriers to stressors like excessive heat or heavy metals, trees produce stress-shielding and signaling compounds which protect the chloroplast and mitochondria from oxidative stress, allowing the tree to flourish. However, there is a tradeoff in resources for growth and development versus permanent stress defense. Philadelphia soil conditions, unlike those in Newark that experienced degradation due to past agricultural practices, were more nutrient rich so those ecosystems held enough nitrogen to allow trees to produce additional stress-responding compounds while also growing into healthier, more productive forests.

McDermot hopes that this red maple study serves as the blueprint for future research on other species commonly found in urban systems.

"This gives us insight into planting the right trees in cities," McDermot said. "We can't just focus on beautification. We need to support ecological resilience. It's about prescribed greening -- planting the right tree species, in the right place, in the right soil conditions and for the right reasons."

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Sanctuary policies protect immigrants but don't threaten public safety

Counties that limit cooperation with ICE see deportations after book-ins to county jails drop by a third, but there's no measurable effect on crime

STANFORD UNIVERSITY - IMMIGRATION POLICY LAB

Research News

 

Sanctuary policies are at the center of the debate over immigration enforcement in the interior of the country. President Trump has called those policies "deadly" and claimed that they prevent the deportation of violent criminals and increase crime.

Those claims are not true, according to a new study published in the Proceedings of the National Academy of Sciences by Stanford University researcher David Hausman, a postdoctoral fellow at Stanford's Bill Lane Center for the American West and an affiliate of Stanford's Immigration Policy Lab.

"What I found is that sanctuary policies really do protect immigrants, and they also don't do any harm to public safety," Hausman said. "In fact, the data show that sanctuary policies have no measurable effect on crime."

Using datasets from Immigration and Customs Enforcement (ICE) and the Federal Bureau of Investigation (FBI), Hausman studied the onset of sanctuary policies in 140 counties between 2010 and 2015. He found the following:

• Sanctuary policies reduced deportations after local arrests by a third.

• Sanctuary had different effects on different groups of noncitizens. For noncitizens without criminal convictions, sanctuary policies reduced these deportations by half, but for noncitizens with violent convictions, sanctuary policies had no measurable effect.

• Sanctuary policies prevented about 22,300 deportations nationwide between 2013 and 2015, including about 3,300 deportations of immigrants who had never been convicted of any crime.

• Sanctuary policies had no measurable effect on crime.

"I hope that this study brings some facts to a debate that has too often relied on assertions," Hausman said.

Delving into the Data

"Sanctuary" describes a wide range of local policies limiting cooperation with federal immigration enforcement. (Sanctuary policies have no impact on whether a person is arrested, charged, convicted, or sentenced for a criminal offense.) This study focuses on sanctuary policies' key element: prohibiting local law enforcement from complying with ICE requests that jails lock up immigrants past the date when they would normally be released.

Every time police officers make an arrest, they send the person's fingerprints to the FBI, which in turn automatically shares them with ICE. If ICE identifies the person as an immigrant eligible for deportation in its own databases, it can issue a detainer to the local jail, requesting that the jail hold the person beyond the scheduled release date. This gives ICE officers extra time to pick up the person and place him or her into deportation proceedings.

For his study, Hausman looked at 369,388 deportations between November 2008 and December 2015 that began when a noncitizen was arrested by local law enforcement. At the time when many sanctuary policies were taking effect (2014-15), this kind of deportation made up 55 percent of all deportations ICE initiated from the interior of the country. Hausman focused on 296 large counties during that period, which accounted for more than 80 percent of all deportations that began with a local arrest. Of those 296 counties, 140 adopted sanctuary policies (or were affected by a state sanctuary policy) between 2010 and 2015.

Hausman then compared sanctuary and non-sanctuary counties before and after the policies were adopted. While the two groups looked roughly the same before the policies were introduced, they diverged just a few months afterward. Deportations fell by a third in sanctuary jurisdictions, but there was no decline in deportations of people with violent convictions.

In a way, it's not surprising that sanctuary policies did not protect people with violent convictions from deportation. Many sanctuary policies make exceptions for violent crimes, allowing local police to comply with ICE detainer requests for noncitizens with such convictions. And people with those convictions are more likely to serve sentences in state prisons, where ICE can easily locate them before their release.

To measure the effect of sanctuary on crime, Hausman looked at 224 large counties, narrowing the list to those that consistently reported crime data each month. Sanctuary policies appeared neither to increase crime rates nor help police solve crimes.

Taken together, these findings show that even as these policies reduce deportations, they do not harm public safety.

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Justice for all: How race and American identity may affect politics

PENN STATE

Research News

 

UNIVERSITY PARK, Pa. -- Allegiance and loyalty to your country is highly valued in America, but what if you feel America doesn't love you back? New research examined whether feeling like you belong in America -- or not -- affected how members of different races and ethnicities participated in politics.

Ray Block Jr., associate professor of political science and African American studies at Penn State, said the study suggests that people who don't embody a typical white American identity may have complicated feelings of Americanness that may also affect their politics.

"We were able to get clues about how feelings of allegiance and belonging work together to affect how a person engages politically, for example by showing up to vote or by protesting," Block said. "Allegiance and belonging can mix together in meaningful ways to influence how much people are involved in a system that they feel they either belong to or which they feel might not love them back."

According to the researchers, the study -- recently published in the National Review of Black Politics -- was partially inspired by the current state of American politics and is important because a true democracy is based on everyone's voices being heard, not just those in majority demographics.

Block said that with debates surging about the separation of immigrant families, police brutality against Black Americans and other people of color, and a rise in white nationalism, he and the other researchers wanted to examine whether those in ethnic or racial minorities might have complicated feelings about their identity in America.

"We started with the idea that certain groups of Americans don't seem to have as much claim to Americanness as other groups do," Block said. "We noticed this in politics because sometimes people will weaponize American patriotism against outsiders. One of the ultimate ways to make someone an outsider is to question their Americanness. For example, when people questioned Colin Kaepernick taking a knee during the national anthem."

For the study, the researchers used data from the 2016 Collaborative Multiracial Post-Election Survey. The survey included 10,144 participants -- with 3,006 identifying as Asian, 3,102 as Black or African American, 3,002 as Latino/a, and 1,034 as white.

The researchers measured "Americanness" with two variables. The first was "belonging," measured by questions such as asking participants whether they felt most Americans valued their presence and whether they felt others tried to exclude them. The second was "allegiance," measured by asking how much being an American is important to them.

Finally, the researchers also looked at two forms of political participation: electoral and non-electoral. Electoral participation refers to actions such as voting and donating money to campaigns while non-electoral participation refers to actions such as signing petitions or participating in marches or protests.

"Non-electoral politics is usually the tool that those who feel voiceless use in politics," Block said. "Protesting and community activism, for example, might be what a person does when they feel outside the system. The more connected to the system you feel, the more likely you won't need non-electoral participation. But the less connected you feel you are to the system, the more appealing non-mainstream forms of political action become."

After analyzing the data, the researchers found that white respondents felt strongly that they belonged in America, while racial and ethnic minorities felt less belonging. Whites also reported higher levels of allegiance. When measuring political participation, whites reported the highest level of electoral participation.

When the researchers examined the connections between Americanness and electoral and non-electoral participation, Block said things got a little murkier. While the findings were statistically insignificant, he said the results still show patterns and clues to how feelings of allegiance and belonging may affect how someone participates politically.

For example, one pattern suggested that when a person's sense of belonging was low, allegiance had no connection to political participation. But when belonging was higher, there was the possibility that also feeling allegiance could increase a person's tendency to vote.

"This makes sense -- if electoral participation represents a very 'mainstream' type of activism, then why would anyone bother to take part in it if they do not think their society values/respects/includes them?" the researchers wrote in the paper. "Furthermore, the findings for non-electoral participation comport well with what we already know. The less highly regarded by their country people feel, the more appealing nonelectoral modes of activism become."

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Stacey Greene, Rutgers University; Gabrielle Gray, Howard University; and Niambi Michele Carter, Howard University, also participated in this work.

 

Study: More than 200 million Americans could have toxic PFAS in their drinking water

ENVIRONMENTAL WORKING GROUP

Research News

 

WASHINGTON - A peer-reviewed study by scientists at the Environmental Working Group estimates that more than 200 million Americans could have the toxic fluorinated chemicals known as PFAS in their drinking water at a concentration of 1 part per trillion, or ppt, or higher. Independent scientific studies have recommended a safe level for PFAS in drinking water of 1 ppt, a standard that is endorsed by EWG.

The study, published today in the journal Environmental Science & Technology Letters, analyzed publicly accessible drinking water testing results from the Environmental Protection Agency and U.S. Geological Survey, as well as state testing by Colorado, Kentucky, Michigan, New Hampshire, New Jersey, North Carolina and Rhode Island.

"We know drinking water is a major source of exposure of these toxic chemicals," said Olga Naidenko, Ph.D., vice president for science investigations at EWG and a co-author of the new study. "This new paper shows that PFAS pollution is affecting even more Americans than we previously estimated. PFAS are likely detectable in all major water supplies in the U.S., almost certainly in all that use surface water."

The analysis also included laboratory tests commissioned by EWG that found PFAS chemicals in the drinking water of dozens of U.S. cities. Some of the highest PFAS levels detected were in samples from major metropolitan areas, including Miami, Philadelphia, New Orleans and the northern New Jersey suburbs of New York City.

There is no national requirement for ongoing testing and no national drinking water standard for any PFAS in drinking water. The EPA has issued an inadequate lifetime health advisory level of 70 ppt for the two most notorious fluorinated chemicals, PFOA and PFOS, and efforts to set an enforceable standard could take many years.

In the absence of a federal standard, states have started to pass their own legal limits for some PFAS. New Jersey was the first to issue a maximum contaminant limit for the compound PFNA, at 13 ppt, and has set standards of 13 ppt for PFOS and 14 ppt for PFOA. Many states have either set or proposed limits for PFOA and PFOS, including California, Massachusetts, Michigan, New Hampshire, New Jersey, New York and Vermont.

"The first step in fighting any contamination crisis is to turn off the tap," said Scott Faber, EWG senior vice president for government affairs. "The second step is to set a drinking water standard, and the third is to clean up legacy pollution. The PFAS Action Act passed by the House would address all three steps by setting deadlines for limiting industrial PFAS releases, setting a two-year deadline for a drinking water standard, and designating PFAS as 'hazardous substances' under the Superfund law. But Mitch McConnell's Senate has refused to act to protect our communities from 'forever chemicals.'"

PFAS are called forever chemicals because they are among the most persistent toxic compounds in existence, contaminating everything from drinking water to food, food packaging and personal care products. They are found in the blood of virtually everyone on Earth, including newborn babies. They never break down in the environment.

Very low doses of PFAS chemicals in drinking water have been linked to suppression of the immune system and are associated with an elevated risk of cancer and reproductive and developmental harms, among other serious health concerns.

"When we look for PFAS contamination, we almost always find it," said David Andrews, Ph.D., a senior scientist at EWG and one of the co-authors. "Americans should trust that their water is safe, but far too many communities have water supplies polluted by toxic PFAS chemicals. These are some of the most insidious chemicals ever produced, and they continue to be used. Our analysis was largely limited to PFOA and PFOS, but many more PFAS are found to contaminate drinking water and the entire class of PFAS chemicals is a concern."

The EPA has identified over 600 PFAS in active use in the U.S. According to the most recent analysis of state and federal data by EWG, 2,230 locations in 49 states are known to have PFAS contamination, including more than 300 military installations.

PFAS contamination has raised alarms among a bipartisan group of lawmakers in Congress. The PFAS Action Act also includes a provision that would set a two-year deadline for the EPA to establish a national drinking water standard for the two most notorious PFAS chemicals - PFOA, formerly used to make DuPont's Teflon, and PFOS, formerly an ingredient in 3M's Scotchgard.

The House versions of the National Defense Authorization Act and EPA spending bill also include important PFAS reforms.

"It's not too late for this Congress to protect us from the growing PFAS contamination crisis," Faber said.

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The Environmental Working Group is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action.

 

Pinpointing the 'silent' mutations that gave the coronavirus an evolutionary edge

RNA folding may help explain how the coronavirus became so hard to stop after it spilled over from wildlife to humans.

DUKE UNIVERSITY

Research News

 

DURHAM, N.C. -- We know that the coronavirus behind the COVID-19 crisis lived harmlessly in bats and other wildlife before it jumped the species barrier and spilled over to humans.

Now, researchers at Duke University have identified a number of "silent" mutations in the roughly 30,000 letters of the virus's genetic code that helped it thrive once it made the leap -- and possibly helped set the stage for the global pandemic. The subtle changes involved how the virus folded its RNA molecules within human cells.

For the study, published Oct. 16 in the journal PeerJ, the researchers used statistical methods they developed to identify adaptive changes that arose in the SARS-CoV-2 genome in humans, but not in closely related coronaviruses found in bats and pangolins.

"We're trying to figure out what made this virus so unique," said lead author Alejandro Berrio, a postdoctoral associate in biologist Greg Wray's lab at Duke.

Previous research detected fingerprints of positive selection within a gene that encodes the "spike" proteins studding the coronavirus's surface, which play a key role in its ability to infect new cells.

The new study likewise flagged mutations that altered the spike proteins, suggesting that viral strains carrying these mutations were more likely to thrive. But with their approach, study authors Berrio, Wray and Duke Ph.D. student Valerie Gartner also identified additional culprits that previous studies failed to detect.

The researchers report that so-called silent mutations in two other regions of the SARS-CoV-2 genome, dubbed Nsp4 and Nsp16, appear to have given the virus a biological edge over previous strains without altering the proteins they encode.

Instead of affecting proteins, Berrio said, the changes likely affected how the virus's genetic material -- which is made of RNA -- folds up into 3-D shapes and functions inside human cells.

What these changes in RNA structure might have done to set the SARS-CoV-2 virus in humans apart from other coronaviruses is still unknown, Berrio said. But they may have contributed to the virus's ability to spread before people even know they have it -- a crucial difference that made the current situation so much more difficult to control than the SARS coronavirus outbreak of 2003.

The research could lead to new molecular targets for treating or preventing COVID-19, Berrio said.

"Nsp4 and Nsp16 are among the first RNA molecules that are produced when the virus infects a new person," Berrio said. "The spike protein doesn't get expressed until later. So they could make a better therapeutic target because they appear earlier in the viral life cycle."

More generally, by pinpointing the genetic changes that enabled the new coronavirus to thrive in human hosts, scientists hope to better predict future zoonotic disease outbreaks before they happen.

"Viruses are constantly mutating and evolving," Berrio said. "So it's possible that a new strain of coronavirus capable of infecting other animals may come along that also has the potential to spread to people, like SARS-CoV-2 did. We'll need to be able to recognize it and make efforts to contain it early."

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CITATION: "Positive Selection Within the Genomes of SARS-CoV-2 and Other Coronaviruses Independent of Impact on Protein Function," Alejandro Berrio, Valerie Gartner, Gregory A Wray. PeerJ, October 16, 2020. DOI: 10.7717/peerj.10234

Stopping the virus and closing borders

Countries with international travel restrictions suffered fewer COVID-19 fatalities

WZB BERLIN SOCIAL SCIENCE CENTER

Research News

 

Until mid-March 2020, the WHO, the EU as well as German authorities were convinced that the spread of the virus could not be curbed by border closures. "This belief was fatally mistaken", argues Ruud Koopmans. "Travel restrictions should be given much greater weight", he urges. "This holds true for containing upcoming waves of the COVID-19 pandemic as well as similar pandemics in the future."

The study draws on sociological accounts of network diffusion and shows that countries that are heavily exposed to international travel and tourism - such as France, Italy, and the USA - recorded significantly higher numbers of deaths. At the same time, death rates in countries more at the margins of international travel networks as well in island states remained comparatively low.

In view of this key role of international travel flows, the study examines the effects of entry bans and mandatory quarantines on COVID-19 mortality. The earlier such travel restriction measures were implemented, the greater was their limiting effect on mortality. Crucially, travel restrictions needed to be in place before the local spread of the virus had spiraled out of control. If one compares countries that imposed travel restrictions until early March to countries that implement them from mid-March onward or not at all, mortality within the first group is an estimated62 percentage points lower than in the second group.

Among the early adopters of travel restrictions with significantly lower death rates are countries such as Australia, Israel and the Czech Republic. Germany, which introduced its first travel restrictions on 16 March, belongs to the late-adopter group, but countries such as Great Britain, France or Brazil responded even later.

The study shows that the type of travel restriction also plays a role. Mandatory quarantines for incoming travelers were more effective than entry bans. A plausible explanation is that entry bans often include exceptions for both citizens and permanent residents. By contrast, quarantine measures tend to apply to all incoming travelers, regardless of their nationality or country of residence. The study further shows that targeted travel restrictions (represented in the study by entry bans and mandatory quarantines for travelers from China or Italy) were more effective than restrictions targeted against all foreign countries.

The study has been published as a WZB Discussion Paper:

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Ruud Koopmans: A Virus That Knows No Borders? Exposure to and Restrictions of International Travel and the Global Diffusion of COVID-19, WZB Discussion Paper SP VI 2020-103, October 2020. https://bibliothek.wzb.eu/pdf/2020/vi20-103.pdf

Ruud Koopmans is the Director of the Migration, Integration, Transnationalization Research Unit at WZB and a Professor of Sociology and Migration Research at the Humboldt-University of Berlin.

 

Covid-19: Pooled testing among recommendations to fix test, trace and isolate system

SAGE

Research News

 

In a series of recommendations to fix the struggling Covid-19 test, trace and isolate system in England, health researchers from University College London and the London School of Hygiene & Tropical Medicine say that pooled testing for Covid-19 could significantly increase testing capacity in a relatively short space of time and help with the identification of asymptomatic cases in key workers.

Writing in the Journal of the Royal Society of Medicine, the researchers say that evaluating samples in batches rather than individually, and re-testing only the groups that come up positive means fewer tests overall would be needed. Several countries, including China, USA, Germany, Portugal, New Zealand, Rwanda, Uruguay, Israel and Vietnam have used pooled testing to considerably increase testing capacity and decrease pressure on lab reagents and operators.

As positivity rates rise, however, pooling becomes less efficient because more samples have to be tested. Co-author Alex Crozier, from the Division of Biosciences at University College London, said: "We are close to missing that window of opportunity in England unless we can control transmission quickly. For now, pooling may be best reserved for surveillance testing and asymptomatic screening of healthcare workers, care homes and hospital pre-admissions."

As well as increased investment in NHS and Public Health England labs to scale up additional testing locally and making use of unused lab capacity in universities and research institutes where possible, the recommendations include the initiation of environmental surveillance by testing wastewater as an early warning system for Covid-19 outbreaks.

The authors also recommend a major investment in people on the ground to support contact tracing. Pointing to Massachusetts where a $44 million contact tracing programme hired and trained 1,000 people to support existing local public health volunteers, the researchers write that this approach is much less costly than the UK government's £100 billion 'Operation Moonshot', and has reached 91.8% of cases and 78.8% of contacts. Recognising the important role played by superspreading events, another of the recommendations is to increase resources to enable a greater focus on identifying clusters using retrospective tracing, as seen in several countries that have been most successful such as Japan, South Korea, and Uruguay.

Another of the authors, Professor Martin Mckee, of the London School of Hygiene & Tropical Medicine, said: "England stands on the edge of a precipice: find, test, trace, isolate and support strategies need to be re-thought to have any chance of avoiding a considerable rise in cases over the coming months requiring a return to stricter social distancing measures nationwide. Our recommendations are feasible, do not require further individual sacrifice and would likely have a significant impact on driving down the reproductive number and reducing the socio-economic impact of the pandemic if they were implemented quickly."

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Malice leaves a nasty smell

Bad attitudes lead to moral judgments rooted in our basic survival mechanisms. And scientists from UNIGE have demonstrated that they are linked to foul smells.

UNIVERSITÉ DE GENÈVE

Research News

 

IMAGE: PART OF THE HUMAN BRAIN CONTRIBUTING THE MOST TO THE PREDICTION OF PAIN AND OLFACTORY DISGUST. view more 

CREDIT: UNIGE/CORRADI-DELL'AQUA

Unhealthy behaviours trigger moral judgments that are similar to the basic emotions that contribute to our ability to survive. Two different hypotheses are to be found in the current scientific literature as to the identity of these emotions. Some researchers single out disgust, while others opt for pain. After developing a new approach to brain imaging, a research team from the University of Geneva (UNIGE) has come down on the side of disgust. The study, which can be found in Science Advances, shows that unhealthy behaviours trigger brain responses that are similar to those prompted by bad smells. The research also identifies for the first time a biomarker in the brain for disgust.

Disgust is a basic emotion linked to our survivability. Smell provides information about the freshness of foodstuffs, while disgust means we can take action to avoid a potential source of poisoning. Following the same principle, pain helps us cope with any injuries we might suffer by activating our withdrawal reflexes. Psychologists believe that these types of survival reflexes might come into play in response to other people's bad behaviour.

Disgust or pain

"These connections have been demonstrated via associations between situations and sensations," begins Professor Corrado Corradi-Dell'Acqua, a researcher in UNIGE's Department of Psychology and the study's lead investigator. "For instance, if I drink something while reading an article about corruption that affects my moral judgment, I may find that my drink smells bad and tastes vile. Equally, the reverse is true: smells can generate inappropriate moral judgment. In concrete terms, if someone smells bad, other people tend to make the judgment that they're unhealthy."

While some studies suggest that disgust is involved in the process, others opt for pain, since they consider that moral judgments are made based on actual facts - hence the parallel with the mechanisms involved in pain. "If a driver is distracted, and does not see a pedestrian crossing a road, I will judge this person more negatively if the pedestrian was actually harmed, rather than avoided by chance", explains the psychologist. His team set up an experimental paradigm and customised magnetic resonance imaging (MRI) techniques in an attempt to decide between the contradictory hypotheses.

The train dilemma as a paradigm

The first step was for Corradi-Dell'Acqua's laboratory to subject volunteers to unpleasant odours or heat-induced pain. "The whole idea was to elicit a similar degree of discomfort with the two techniques so that they could work on the same levels." Once the calibration had been performed, participants in the study were subjected to readings that evoked value judgments. "We used the train dilemma when five people are stuck on a railway track as a train approaches. The only possible way to save them is to push someone off the top of a bridge so that the switch is hit as they fall. In other words, it's necessary to kill one person to save five in a highly immoral situation," explains the researcher. The act of reading this unpleasant dilemma had an influence on the odours the participants smelt and caused disgust, but did not influence the pain, an outcome that was backed up by the participants' electrodermal activity. This is a physiological measurement of the electrical conductance of the skin. It reflects the rate of sweating and the activity of the nervous system responsible for involuntary behaviour.

Neural pathways identified

Professor Corradi-Dell'Acqua then concentrated on the brain response. "It is difficult to infer pain and disgust from neural activity, as these two experiences often recruit the same brain areas. To dissociate them, we had to measure the global neuronal activity via MRI rather than focusing on specific regions," summarises the researcher. The Geneva team adopted a technique that allows predicting disgust and pain from the overall brain activity, such as specific biomarkers.

Using this tool, the researchers were able to prove that the overall brain response to disgust was influenced by previous moral judgment. Once again, moral judgments are indeed associated with disgust. "In addition to this important discovery for psychology, this study was the occasion for the development of a biomarker prototype for olfactory disgust. It's a double step forward!" concludes Corradi-Dell'Acqua.

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