Intersecting social inequities increase the likelihood of severe illness due to COVID-19

by University of Toronto

Credit: Pixabay/CC0 Public Domain

Black, South Asian and Aboriginal populations from disadvantaged socioeconomic backgrounds in Canada are nearly four times more likely to have three or more medical conditions that have been identified as risk factors for severe illness from COVID-19.

Shen (Lamson) Lin, a doctoral candidate in gerontology and course instructor at the University of Toronto's Factor-Inwentash Faculty of Social Work and Institute for Life Course and Aging, compared 1,102 racialized immigrants and 338 Aboriginal Canadians with 23,802 Canadian-born Whites, aged 45 and older, using population-based data from the baseline Canadian Longitudinal Study on Aging (CLSA, 2012-2015). His findings were recently published in The Gerontologist (Special collection: Gerontology in a Time of Pandemic).

"We know that COVID-19 outbreak is not affecting everyone at the same levels, and the prevalence of multiple chronic conditions within an individual—known as multimorbidity—has also been linked to social inequalities for decades," says Lin, the sole author of the study. "I was curious to explore how one's family income, education levels and experience of racism and nativism—and the intersection of these three social standings—shape the health of aging populations."

Lin's study examined nine chronic conditions associated with an increased likelihood that one will experience severe illness due to COVID-19 infection, requiring hospitalization, intensive care and the use of a ventilator. These medical conditions include diabetes, asthma, cancer, previous heart attack or myocardial infarction, kidney disease, cardiovascular disease, hypertension, chronic obstructive pulmonary disease and obesity.

The odds of having three or more of these medical conditions was greater for Black and South Asian immigrants and close to double for Aboriginal populations in Canada, relative to Canadian-born Whites. Black, South Asian and Aboriginal populations from disadvantaged socioeconomic backgrounds (those without any post-secondary education and/or those who earned less than the median household income) had the highest odds of having three or more medial conditions.

The multimorbidity differences associated with these populations were enhanced for older adults (aged 66 to 85) compared to their middle-aged counterparts (aged 45-65). Among older respondents, Black immigrants were five times more likely and Aboriginal Canadians three times more likely to have three or more medical conditions.

"These observed health gaps illustrate various minority struggles that are often obscured within a discourse of multiculturalism and diversity" says Lin, "Given the lack of socio-demographic and race-based data in Canadian health systems, my study provides a timely frame of reference for public-health decision makers to reconsider measuring upstream health inequalities to mitigate the pandemic's long-term societal harms."

Additional risk factors for multimorbidity were identified. These included being male, experiencing chronic pain, having a physical impairment, living without partners, and a lifetime of smoking.

"Widespread chronic disease and racism in addition to the contemporary pandemic make living conditions more difficult for vulnerable older adults, especially those from racialized, immigrant, and impoverished communities," says Lin. "With COVID-19 spreading globally, health equity should be placed at the center of all policy responses designed to mitigate the disproportionate impact of the pandemic on underserved aging communities."

Explore further Follow the latest news on the coronavirus (COVID-19) outbreak

More information: Shen (Lamson) Lin, Intersectionality and inequalities in medical risk for severe COVID-19 in the Canadian Longitudinal Study on Aging, The Gerontologist (2020). DOI: 10.1093/geront/gnaa143

Provided by University of Toronto

COVID-19 infected workers return to work faster using time and symptom-based protocols

by Massachusetts General Hospital

Credit: CC0 Public Domain

One of the of the most important questions in managing a hospital's response to the COVID-19 pandemic is determining when healthcare workers infected with COVID-19 can return to the job. Recently, investigators from Mass General Brigham (MGB) assessed the experience of using a test-based protocol in over 1,000 infected health care workers.


Their research was published in the latest edition of Infection Control & Hospital Epidemiology.

The "test-based" approach involves repeat testing after resolution of symptoms until two consecutive negative tests are obtained 24 hours apart. In the alternative time-plus-symptoms approach, healthcare workers return to work after a set period of time since their symptom onset (or in the case of asymptomatic infection, the date of their positive test) has elapsed and symptoms, if present, have improved or resolved.

"We've learned a lot throughout the pandemic," explains Erica S. Shenoy, MD, Ph.D., associate chief of the Infection Control Unit at Massachusetts General Hospital (MGH) and the study's lead author. "For example, we now know from multiple published studies that individuals can have repeat positive tests for weeks and those positive test do not reflect infectivity after their initial illness has resolved." These findings have led to modifications in how public health and healthcare facilities determine how long individuals need to be isolated to prevent transmission to others, Shenoy says.

The Centers for Disease Control and Prevention (CDC)'s April guidance advised either repeat "test-based" strategy to determine when workers could return to their healthcare jobs or "time-plus-symptoms" approach. Under the test-based strategy, healthcare workers had to have two negative back-to-back PCR tests to return to work.

For this study, conducted between March 7 and April 22, 2020, employees from across Mass General Brigham (MGB) health system who showed symptoms of COVID-19 were referred to its Occupational Health Services department for evaluation and a nasopharyngeal (NP) sample test using viral RNA nucleic acid amplification methods.

Return to work criteria at that time required: resolution of fever without fever-reducing medications, improvement in respiratory symptoms, and at least two consecutive negative nasopharyngeal tests collected longer than or equal to 24 hours apart. There was no minimum interval of time from resolution of symptoms to first test of clearance specified.


The researchers then analyzed the data to evaluate results of the two strategies and found that using resolution of symptoms and passage of time would have averted more than 4,000 days of lost worktime, or a mean of 7.2 additional days of work lost per employee compared to using a time-plus-symptom approach. Both approaches are options per public health recommendations, though more recently, the time-plus-symptom approach is now the preferred strategy per the CDC the Massachusetts Department of Public Health, and has replaced the prior test-based approach at MGB. One additional potential benefit of moving away from test-based approaches, though not assessed in this study, was the psychological impact on employees of repeat testing. "We've had employees who tested positive repeatedly but had recovered for weeks and they were frustrated we couldn't bring them back to work," Shenoy says. About 70 percent of participants had at least one negative test result during the study, and of those, about 62 percent had a two negative test results in a row, she adds.

A substantial number of healthcare workers diagnosed and treated for COVID-19 had repeatedly positive PCR tests. Such long duration of PCR positivity has been seen in other studies as well.

Determining when workers can return to work is a process that can affect many aspects of hospital operations, Shenoy says. "Patient and worker safety, flow of resources, speed and access to care, are some of the things impacted."

Based on the studies findings, and evolving public health guidance to prefer time-plus-symptom over test-based strategies, MGB moved to the latter over the summer. "Moving to a time+symptom approach was a vast improvement over past reliance on a less predictable test-based approach. Employees are now able to anticipate when they will be allowed to return to work, and it has reduced the strain on our testing capacity. This revision in testing strategy is consistent with our evolving medical understanding of test results and in keeping with our high commitment to workplace safety," said Dean Hashimoto, MD, chief medical officer of MGB Occupational Health Services.

Explore further  Follow the latest news on the coronavirus (COVID-19) outbreak

More information: Erica S. Shenoy et al, Healthcare worker infection with SARS-CoV-2 and test-based return to work, Infection Control & Hospital Epidemiology (2020).

DOI: 10.1017/ice.2020.438

Provided by Massachusetts General Hospital

During pandemic, racism puts additional stress on Asian Americans

by Sarah Alger, Massachusetts General Hospital

Credit: Unsplash/CC0 Public Domain

Many people are feeling anxious during these uncertain times as they navigate the risks associated with COVID-19 and experience the tension from physical distancing or isolation for what can seem like an eternity. But people of Asian ancestry face yet another set of challenges posed by racism and xenophobia which has soared during the COVID-19 pandemic amidst rumors and blame placed on China.


This pandemic-driven rise in anti-Asian racism is so pronounced, that in a commentary recently published in the American Journal of Public Health, psychiatrist Justin A. Chen, MD, MPH, and his coauthors have described it as a "secondary contagion" threatening this population.

Chen is an investigator in the Department of Psychiatry at Massachusetts General Hospital (MGH) and an assistant professor at Harvard Medical School. In addition, he serves as executive director and co-founder of the MGH Center for Cross Cultural Student Emotional Wellness. He is lead author on the commentary, and his co-authors are Emily Zhang Counseling Psychology Ph.D. candidate at Boston College Lynch School of Education and Human Development and Cindy H. Liu, director of the Developmental Risk and Cultural Resilience Program within Pediatric Newborn Medicine and Psychiatry at Brigham and Women's Hospital.

The United States, the authors report, is no exception to this trend toward an uptick in anti-Asian racism during the pandemic. In the U.S., Asians share a long and well-documented history of discrimination and have been the frequent targets of both interpersonal and structural persecution. Asians of all ethnicities have been scapegoated, verbally attacked with racial slurs, coughed at, spat on, physically assaulted and more.

Observers may consider such acts as just small slights or brief episodes that can be shrugged off. But there is strong evidence that they can have much more serious effects than most people realize, especially on people who are already vulnerable.

In their commentary, Chen and his collaborators provide an overview of the history of anti-Asian discrimination in the United States, reviewing associations between discrimination and health, describing the associated public health implications of the COVID-19 pandemic and reviewing evidence from previous disasters in U.S. history that were "racialized."

The scope of the problem is large and growing. Asian Americans comprise just 5.6 percent of the US population. However, they are the fastest-growing racial/ethnic group in the country, with a 72 percent increase from 2001 to 2015, and are projected to become the largest immigrant group by 2055.


"Prior to the pandemic, Asians were often held up as the 'model minority' who were always successful and excelled at academics," explains Chen. This seemingly positive stereotype comes with its own set of problems, including overlooking differences between different Asian ethnicities and added pressure for Asian American youths to conform to a certain ideal of success and hide their challenges. But since COVID-19 swept across the world and news spread that the virus had originated in China, stereotyping of Asians has assumed a more negative tone, resulting in increasing racism, suspicion, xenophobia, bullying and even more aggressive behavior.

Stop AAPI Hate, a U.S.-based Web site created in March 2020 to track attacks against Asian Americans, received 1135 reports nationwide within the first two weeks of launching. Moreover, the FBI has warned of increased hate crimes against Asian Americans. The cumulative burden of these incidents, along with their coverage in the media, has the potential to exert significant negative health effects.

That trend is starting to be more widely appreciated, Chen says. For example, two recent reports released by the two groups Stop AAPI Hate and Stop Asian Americans and Pacific Islanders (AAPI) Hate Youth Campaign, both looked at the impact of racism and xenophobia against Asian-American youth during the COVID-19 pandemic.

The report They Blamed Me Because I Am Asian, was written and analyzed by the Stop AAPI youth campaign—a group of 87 high school interns—and based on nearly 1,000 interviews they conducted with AAPI youth over the summer. The Stop AAPI Hate report, meanwhile, was written by experts who analyzed 341 incidents of anti-Asian discrimination involving youth reported to the Stop AAPI Hate reporting center from March 19—July 22, 2020.

Findings from the 990 interviews in They Blamed Me Because I Am Asian show that eight out of 10 Asian American youth (77 percent) expressed anger over the current anti Asian hate in this nation, and six out of 10 (60 percent) are disappointed over the racism. Incidents of harassment focused on blaming China and Chinese people as the source of the virus and on mocking Chinese dietary habits, such as the consumption of bats.

Chen emphasizes that not all the news is bad. Positive developments include the emergence of mechanisms for reporting and tracking incidents of racial bias, increased awareness of racism's insidious harms and subsequent civic and political engagement by the Asian American community, and further research into resilience-promoting factors that can reduce the negative health effects of racism.


Explore further Follow the latest news on the coronavirus (COVID-19) outbreak

More information: Justin A. Chen et al, Potential Impact of COVID-19–Related Racial Discrimination on the Health of Asian Americans, American Journal of Public Health (2020). DOI: 10.2105/AJPH.2020.305858

Journal information: American Journal of Public Health

Provided by Massachusetts General Hospital

How do Americans view the virus? Anthropology professor examines attitudes of COVID

NORTHERN ARIZONA UNIVERSITY

Research News

 

In her ongoing research about Americans' responses to the COVID-19 pandemic, Northern Arizona University anthropology professor Lisa Hardy and her collaborators have talked to dozens of people. A couple of them stand out to the researchers.

Hardy spoke to a man who had polio as a child and had to live in a home with an iron lung away from his family. He said he was not in good health but he was not afraid of COVID-19 because he has seen all of this. A woman told anthropology lecturer Leah Mundell that she was the only Spanish-speaking contact tracer in her county, and she took on the responsibility of helping clients with much more than their physical health, connecting them with services and translating for them as they struggled to access resources.

Hardy's research, to which Mundell contributed, was published this week in Medical Anthropology. "Connection, Contagion, and COVID-19" looks at how Americans' attitudes and responses have changed during the time of the pandemic and how to many people, the virus is not a biological agent but instead a malicious actor. This perception may play a role in the various responses Hardy's team heard, including comments about racism, social justice and mistrust of information.

"Social scientists have done an excellent job of exploring past pandemics with regard to xenophobia--the 'Spanish Flu,' for instance--and how people understand bodies and illness," Hardy said. "This work builds on that by examining the COVID-19 pandemic in the current political moment. The results of this and other research can help to inform areas where collaborative interventions could potentially help to slow the spread of the virus and support well-being for people living through this time."

The research project, which is a collaboration as part of the Social Science Community Engagement Lab, started six months ago, in the early days of the pandemic in the United States. Researchers, including Hardy, Mundell and two others, conducted semi-structured conversational phone interviews with 50 diverse participants. They asked open-ended questions about how people are dealing with the pandemic and their experiences of social and political responses. Then they transcribe the recorded interviews and apply codes to the transcripts to identify patterns. Hardy said this qualitative strategy is ideal for exploring a situation that is rapidly changing and unfolding over time.

As they've called more people, the researchers have seen the interview content change. In more recent interviews, people talked about social uprisings like Black Lives Matter. They're analyzing the relationship between these social movements and perceptions of COVID-19.

Researchers also are talking to more people who have had COVID-19 or had loved ones who got sick. Recent data includes how people reflect on medical care and contact tracing; that information will be useful for pandemic response. They also will continue interviewing after the Nov. 3 election, which will offer insight into the politicization of the pandemics and its effects.

Tracing the logic of different groups also is important for the group's research. Hardy said they've seen an increase in conspiracy theories in more recent interviews, as people across the political spectrum develop unfounded theories about the virus and its reach.

"We want to understand where these ideas are coming from and see how they influence behavior like vaccine uptake, health practices and voting patterns," she said.

The article includes specific responses researchers have collected as they describe their experiences. They run the gamut; interviewees shared fears, concerns and conspiracy theories. Other interviewees talked at length about new connections and circles of care they have formed to help others and to accept help when needed.

"The strength of some of the people who are having to live through hardships is really heartwarming to us," Hardy said. "It gives us hope in this time of tragic loss and tension in the United States."

While the long-term effects of the pandemic are impossible to predict at this point, Hardy anticipates ongoing effects from the loss of loved ones and inability to grieve together as well as long-term health effects in people who survive COVID-19 but continue to have symptoms. But, she added, the country is seeing the development of creative and dynamic strategies for connection and resilience that will hopefully persist through generations.

###

COVID-19 shapes political approval ratings

by University of North Carolina at Chapel Hill

Credit: CC0 Public Domain

Approval ratings of political leaders surged in the early days of the COVID-19 pandemic, according to a new study published in the Proceedings of the National Academy of Sciences.


In the days and weeks with high numbers of new COVID-19 cases there were also large boosts to leader approval. These results support a "rally 'round the flag" phenomenon in which citizens rally around their leaders during times of crisis and may have voting implications.

Data analyzed by the University of North Carolina at Chapel Hill and the National University of Singapore reveal world leaders, on average, experienced a 14-point boost in approval.

Citizens tend to support their leaders in times of national crisis, such as war or terrorist attack, but the new study is the first to identify a rally effect during a health crisis—one that's been deadly and destructive across the globe.

The idea for the paper was developed by Kai Chi (Sam) Yam, associate professor and dean's chair in the Department of Management and Organization in Singapore. Yam collaborated with Joshua Conrad Jackson, a doctoral student in psychology at UNC-Chapel Hill who conducted the analyses and co-wrote the paper.

Drawing from political science and psychological theories, the study authors and their colleagues examined the effect of COVID-19 cases on approval ratings through the first 120 days of 2020.

More than 2 million daily approval ratings were collected for 11 heads of government from geographically and culturally diverse countries and all 50 United States governors.

U.S. President Donald J. Trump had a scant 4-point gain out of a possible 100 in approval during the time period compared to the substantial 24- to 61-point boosts in approval for leaders in the United Kingdom, Canada, Germany, and Australia. U.S. governors experienced 15- to 20-point gains.

"COVID-19 might serve as a catalyst to help some incumbent governments win election," said Yam.

For example, the Korean ruling party won the most seats in the house by any party since 1960 in an election held during the pandemic in April 2020.

"We collected our data during the early stages of the pandemic, so we aren't equipped to answer questions about the effect's endurance. Clearly the effect doesn't last forever, but its timeline may depend on several factors, including how effectively a leader is perceived to respond to the pandemic," Jackson said.


Explore further 

Mask mandates delayed by nearly a month in Republican-led states, study finds

More information: The rise of COVID-19 cases is associated with support for world leaders, Proceedings of the National Academy of Sciences (2020).

DOI: 10.1073/pnas.2009252117 , www.pnas.org/content/pnas/earl … /2009252117.full.pdf

Journal information: Proceedings of the National Academy of Sciences


Provided by University of North Carolina at Chapel Hill

Reminders of inequality for poor people prod them to be more likely to want to tax the rich

by Bob Yirka , Phys.org

Credit: Pixabay/CC0 Public Domain

A pair of political science researchers at the University of California, has found that showing people a symbol of inequality can push them to demand that rich people be taxed more. In their paper published in the journal Nature, Melissa Sands and Daniel de Kadt outline an experiment they conducted with poor people living in South Africa and an expensive car. Colin Tredoux and John Dixon with the University of Cape Town and the Open University, respectively, have published a News & Views piece in the same journal issue outlining the work by the team in South Africa and issues with their findings.


Prior research has shown that financial inequality can have a detrimental impact on people who live on the lower end of the economic spectrum, including a shorter lifespan and a lower quality of life. Prior research has also looked into the psychological impact of living as a poor person in a society where there is abundance, such as the U.S. In this new effort, the researchers wanted to better understand the factors that motivate people living in poverty to demand changes that might improve their lot. To learn more, they devised an experiment to gage whether poor people are more likely to demand change (in the form of voting to increase taxes on the rich) if they were reminded of the income disparity that exists around them.

The experiment consisted of parking an expensive car on different streets in Soweto—a very poor town in South Africa—and then asking people who passed by to sign a petition. One of the petitions asked whether the government should increase taxes on the rich, while the other petition asked if nuclear power plants should be shut down in the country. In some scenarios, the expensive car was present nearby; in others it was not.

The researchers found that the presence of the car had an immediate impact: 9% fewer people agreed to stop and sign either petition. They also found that 11% more people were willing to sign the petition advocating increasing taxes on the rich when the expensive car was present.




Explore further

Field study suggests wealthy less willing to tax rich when poor people are around
More information: Melissa L. Sands et al. Local exposure to inequality raises support of people of low wealth for taxing the wealthy, Nature (2020). 

DOI: 10.1038/s41586-020-2763-1

Journal information: Nature

How earthquake swarms arise

by Josie Garthwaite, Stanford University

Credit: Pixabay/CC0 Public Domain

Earthquakes can be abrupt bursts of home-crumbling, ground-buckling energy when slices of the planet's crust long held in place by friction suddenly slip and lurch.

"We typically think of the plates on either side of a fault moving, deforming, building up stresses and then: Boom, an earthquake happens," said Stanford University geophysicist Eric Dunham.

But deeper down, these blocks of rock can slide steadily past one another, creeping along cracks in Earth's crust at about the rate that your fingernails grow.

A boundary exists between the lower, creeping part of the fault, and the upper portion that may stand locked for centuries at a stretch. For decades, scientists have puzzled over what controls this boundary, its movements and its relationship with big earthquakes. Chief among the unknowns is how fluid and pressure migrate along faults, and how that causes faults to slip.

A new physics-based fault simulator developed by Dunham and colleagues provides some answers. The model shows how fluids ascending by fits and starts gradually weaken the fault. In the decades leading up to big earthquakes, they seem to propel the boundary, or locking depth, a mile or two upward.

Migrating swarms

The research, published Sept. 24 in Nature Communications, also suggests that as pulses of high-pressure fluids draw closer to the surface, they can trigger earthquake swarms—strings of quakes clustered in a local area, usually over a week or so. Shaking from these seismic swarms is often too subtle for people to notice, but not always: A swarm near the southern end of the San Andreas Fault in California in August 2020, for example, produced a magnitude-4.6 quake strong enough to rattle surrounding cities.

Each of the earthquakes in a swarm has its own aftershock sequence, as opposed to one large mainshock followed by many aftershocks. "An earthquake swarm often involves migration of these events along a fault in some direction, horizontally or vertically," explained Dunham, senior author of the paper and an associate professor of geophysics at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth).

The simulator maps out how this migration works. Whereas much of the advanced earthquake modeling of the last 20 years has focused on the role of friction in unlocking faults, the new work accounts for interactions between fluid and pressure in the fault zone using a simplified, two-dimensional model of a fault that cuts vertically through Earth's entire crust, similar to the San Andreas Fault in California.


"Through computational modeling, we were able to tease out some of the root causes for fault behavior," said lead author Weiqiang Zhu, a graduate student in geophysics at Stanford. "We found the ebb and flow of pressure around a fault may play an even bigger role than friction in dictating its strength."

Underground valves

Faults in Earth's crust are always saturated with fluids—mostly water, but water in a state that blurs distinctions between liquid and gas. Some of these fluids originate in Earth's belly and migrate upwards; some come from above when rainfall seeps in or energy developers inject fluids as part of oil, gas or geothermal projects. "Increases in the pressure of that fluid can push out on the walls of the fault, and make it easier for the fault to slide," Dunham said. "Or, if the pressure decreases, that creates a suction that pulls the walls together and inhibits sliding."

For decades, studies of rocks unearthed from fault zones have revealed telltale cracks, mineral-filled veins and other signs that pressure can fluctuate wildly during and between big quakes, leading geologists to theorize that water and other fluids play an important role in triggering earthquakes and influencing when the biggest temblors strike. "The rocks themselves are telling us this is an important process," Dunham said.

More recently, scientists have documented that fluid injection related to energy operations can lead to earthquake swarms. Seismologists have linked oil and gas wastewater disposal wells, for example, to a dramatic increase in earthquakes in parts of Oklahoma starting around 2009. And they've found that earthquake swarms migrate along faults faster or slower in different environments, whether it's underneath a volcano, around a geothermal operation or within oil and gas reservoirs, possibly because of wide variation in fluid production rates, Dunham explained. But modeling had yet to untangle the web of physical mechanisms behind the observed patterns.

Dunham and Zhu's work builds on a concept of faults as valves, which geologists first put forth in the 1990s. "The idea is that fluids ascend along faults intermittently, even if those fluids are being released or injected at a steady, constant rate," Dunham explained. In the decades to thousands of years between large earthquakes, mineral deposition and other chemical processes seal the fault zone.

With the fault valve closed, fluid accumulates and pressure builds, weakening the fault and forcing it to slip. Sometimes this movement is too slight to generate ground shaking, but it's enough to fracture the rock and open the valve, allowing fluids to resume their ascent.

The new modeling shows for the first time that as these pulses travel upward along the fault, they can create earthquake swarms. "The concept of a fault valve, and intermittent release of fluids, is an old idea," Dunham said. "But the occurrence of earthquake swarms in our simulations of fault valving was completely unexpected."

Predictions, and their limits

The model makes quantitative predictions about how quickly a pulse of high-pressure fluids migrates along the fault, opens up pores, causes the fault to slip and triggers certain phenomena: changes in the locking depth, in some cases, and imperceptibly slow fault movements or clusters of small earthquakes in others. Those predictions can then be tested against the actual seismicity along a fault—in other words, when and where small or slow-motion earthquakes end up occurring.

For instance, one set of simulations, in which the fault was set to seal up and halt fluid migration within three or four months, predicted a little more than an inch of slip along the fault right around the locking depth over the course of a year, with the cycle repeating every few years. This particular simulation closely matches patterns of so-called slow-slip events observed in New Zealand and Japan—a sign that the underlying processes and mathematical relationships built into the algorithm are on target. Meanwhile, simulations with sealing dragged out over years caused the locking depth to rise as pressure pulses climbed upward.

Changes in the locking depth can be estimated from GPS measurements of the deformation of Earth's surface. Yet the technology is not an earthquake predictor, Dunham said. That would require more complete knowledge of the processes that influence fault slip, as well as information about the particular fault's geometry, stress, rock composition and fluid pressure, he explained, "at a level of detail that is simply impossible, given that most of the action is happening many miles underground."

Rather, the model offers a way to understand processes: how changes in fluid pressure cause faults to slip; how sliding and slip of a fault breaks up the rock and makes it more permeable; and how that increased porosity allows fluids to flow more easily.

In the future, this understanding could help to inform assessments of risk related to injecting fluids into the Earth. According to Dunham, "The lessons that we learn about how fluid flow couples with frictional sliding are applicable to naturally occurring earthquakes as well as induced earthquakes that are happening in oil and gas reservoirs."


Explore further Natural fluid injections triggered Cahuilla earthquake swarm

More information: Weiqiang Zhu et al, Fault valving and pore pressure evolution in simulations of earthquake sequences and aseismic slip, Nature Communications (2020). 

DOI: 10.1038/s41467-020-18598-z

Journal information: Nature Communications


Provided by Stanford University

REPORT
A neural correlate of sensory consciousness in a corvid bird
Science 25 Sep 2020:
Vol. 369, Issue 6511, pp. 1626-1629
DOI: 10.1126/science.abb1447

Consciousness shared

Humans have tended to believe that we are the only species to possess certain traits, behaviors, or abilities, especially with regard to cognition. Occasionally, we extend such traits to primates or other mammals—species with which we share fundamental brain similarities. Over time, more and more of these supposed pillars of human exceptionalism have fallen. Nieder et al. now argue that the relationship between consciousness and a standard cerebral cortex is another fallen pillar (see the Perspective by Herculano-Houzel). Specifically, carrion crows show a neuronal response in the palliative end brain during the performance of a task that correlates with their perception of a stimulus. Such activity might be a broad marker for consciousness.

Science, this issue p. 1626; see also p. 1567

Abstract

Subjective experiences that can be consciously accessed and reported are associated with the cerebral cortex. Whether sensory consciousness can also arise from differently organized brains that lack a layered cerebral cortex, such as the bird brain, remains unknown. We show that single-neuron responses in the pallial endbrain of crows performing a visual detection task correlate with the birds’ perception about stimulus presence or absence and argue that this is an empirical marker of avian consciousness. Neuronal activity follows a temporal two-stage process in which the first activity component mainly reflects physical stimulus intensity, whereas the later component predicts the crows’ perceptual reports. These results suggest that the neural foundations that allow sensory consciousness arose either before the emergence of mammals or independently in at least the avian lineage and do not necessarily require a cerebral cortex.

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Singing sexy back: How sparrows adapted to COVID-19 shutdown

A male white-crowned sparrow sings to protect his territory and attract mates in San Francisco

As the streets of San Francisco emptied out in the first months of the pandemic, the city's male birds began singing more softly and improving their vocal range, making them "sexier" to females, according to a new study published Thursday.

The paper adds to a growing body of research describing how animals—from whales to coyotes to the white-crowned sparrow studied here—have adapted their behaviors to COVID-19 shutdowns that forced humans to retreat to their homes, a phenomenon dubbed the "anthropause."

"When the city was loud, they were singing really loudly," Elizabeth Derryberry, a behavioral ecologist at the University of Tennessee, who led the study published in Science, told AFP.

But as traffic ground to a halt following a statewide shelter-in-place order in spring, noise levels fell by 50 percent, she said.

The number of vehicles on the Golden Gate Bridge collapsed to 1954 levels, the researchers found.

They compared birdsong data they had collected from previous years to recordings made at the same sites from April to May 2020, finding the sparrows were now singing far more quietly, and were able to hit much lower notes, which in turn expanded their range and enhanced their overall performance.

Imagine going to a party at a friend's house: at the start of the night you speak at a normal volume, but as the place fills up you have to raise your voice to be heard.

"When you're shouting at a cocktail party, your voice is not at its best," said Derryberry, adding that it was similar for birds.

As noise pollution decreased, "their songs also sounded better, they sounded sexier," she said.

"They were better competitors, and they sounded like better mates to females."

A new paper adds to a growing body of research describing how animals—from whales to coyotes to the white-crowned sparrow (seen here)—have adapted their behaviors to the Covid-19 shutdowns

The scientists were surprised by just how far the volume of their songs had dropped—almost a third.
Species factfile on the white-capped sparrows.

But despite this, the sparrows' trills could still be heard from twice as far away compared to before the shutdown, tying in with anecdotal reports of birdsongs becoming more conspicuous to humans.

Graphic on a study of birdsong in San Francisco during the lockdown period earlier this year.

The authors said their research showed just how quickly birds can adapt to changing environments, and suggest that finding long-term solutions to curbing noise pollution might lead to other positive outcomes like higher species diversity.


Explore further Songbirds, like people, sing better after warming up

More information: E.P. Derryberry el al., "Singing in a silent spring: Birds respond to a half-century soundscape reversion during the COVID-19 shutdown," Science (2020). science.sciencemag.org/cgi/doi … 1126/science.abd5777

Journal information: Science


© 2020 AFP

Tracking shape changes in Amazon fish after major river is dammed

by R. Craig Albertson, University of Massachusetts Amherst

ANOTHER AMAZING DISCOVERY IN THE MUSEUM STORAGE ROOM

UMass Amherst biologists compared museum collections of cichlid fishes from before a dam was closed in 1984 on the Tocantins River in the Brazilian Amazon to contemporary specimens taken from the Tucuruí Reservoir by fishermen 34 years later. They tested the idea that these fish could be expected to show body shape changes - in particular jaw bones - in response to habitat and foraging behavior shifts after the dam changed the waterway. Credit: UMass Amherst/Albertson lab

CHICLIDS ARE POPULAR AGUARIUM FISH LIKE GOURAMIS

A team of biologists led by Craig Albertson and Ph.D. student Chaise Gilbert at the University of Massachusetts Amherst report this week on their comparison between museum collections of cichlid fishes collected before a dam was closed in 1984 on the Tocantins River in the Amazon and contemporary specimens taken from the Tucuruí Reservoir by fishermen 34 years later.


Working with others in Brazil, Albertson's team tested the idea that these fish could be expected to show changes in body shape as a consequence to shifts in habitat and foraging behavior after the dam rapidly changed environmental conditions from a clear, flowing river to a deep, murky reservoir.

"The once-historic rapids and streams that characterized the system have disappeared from the surrounding area, which in turn has affected the abundance and variety of food sources available to native fishes," they write in Evolutionary Application this week.

Cichlid fishes are known in the scientific world for their ability to alter, in as little as a single season, aspects of body shape to match feeding conditions and other changes in the environment, Albertson says. The skeleton is especially sensitive to such environmental inputs, and studying cichlid fishes offers insights into how organisms, in general, may adapt to major human-induced environmental change.

Using geometric morphometrics, the researchers evaluated changes in six native species—from large fish-eating species to small opportunistic omnivores -across five genera representing distinct local varieties whose body shapes reflect their ecological roles.

To accomplish this, the researchers used many specimens from fish inventories collected before the dam closure in 1980-1982 now housed in the Instituto Nacional de Pesquisas da Amazônia fish collection, plus even earlier river survey specimens housed now at the Museu de Zoologia da Universidade de São Paulo.

Albertson explains, "Our overarching hypothesis is that the damming of the Tocantins and subsequent formation of the Tucuruí reservoir has induced shifts in habitat and foraging behavior and that the anatomy of resident cichlid populations has change in ways that allow them to adapt to this novel environmental conditions. This study represents a first step toward assessing this hypothesis."

Gilbert adds, "Was anything surprising? Yes! While we expected to see changes in generalist species—those that are already predisposed toward living in a variety of habitats—we were surprised to see shape changes in the specialists as well. Evolving to specialize on a particular prey-type or habitat, can provide a competitive advantage in the near term, but it can also be an evolutionary dead end in the face of a major environmental changes."

Not only are these specialist species still found in the area, but they seem to be just as capable of changing body shape as the generalists, the authors report.

Albertson reports further thatchanges across all species "tended to be associated with functionally relevant aspects of anatomy, including head, fin and body shape." They found that the regions of the body that changed over time are exactly those most likely to allow them to survive in their new environment, he adds.

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More information: M. Chaise Gilbert et al, Rapid morphological change in multiple cichlid ecotypes following the damming of a major clearwater river in Brazil, Evolutionary Applications (2020). DOI: 10.1111/eva.13080

Provided by University of Massachusetts Amherst