Culture

Using real-time deformability cytometry, researchers at the Max-Planck-Zentrum für Physik und Medizin in Erlangen were able to show for the first time: Covid-19 significantly changes the size and stiffness of red and white blood cells - sometimes over months. These results may help to explain why some affected people continue to complain of symptoms long after an infection (long Covid).

Shortness of breath, fatigue and headaches: some patients still struggle with the long-term effects of a severe infection by the SARS-CoV-2 coronavirus after six months or more. This post Covid-19 syndrome, also called long covid, is still not properly understood. What is clear is that -- during the course of the disease -- often blood circulation is impaired, dangerous vascular occlusions can occur and oxygen transport in is limited. These are all phenomena in which the blood cells and their physical properties play a key role.

To investigate this aspect, a team of scientists led by Markéta Kubánková, Jochen Guck, and Martin Kräter from the Max-Planck-Zentrum für Physik und Medizin, the Max Planck Institute for the Science of Light (MPL), the Friedrich Alexander University Erlangen-Nuremberg and the German Centre for Immunotherapy measured the mechanical states of red and white blood cells. "We were able to detect clear and long-lasting changes in the cells -- both during an acute infection and even afterwards," reports Professor Guck, currently managing director of MPL. The research group has now published their results in the renowned journal Biophysical Journal.

To analyse the blood cells, they used a self-developed method called real-time deformability cytometry (RT-DC), which has recently been recognized with the prestigious Medical Valley Award. In this method, the researchers send the blood cells through a narrow channel at high speed. In the process, the leukocytes and erythrocytes are stretched. A high-speed camera records each of them through a microscope, and custom software determines which cell types are present, and how big and deformed they are. Up to 1000 blood cells can be analysed per second. The advantage of the method: It is fast and the cells do not have to be labelled in a laborious procedure.

The method could help as an early warning system to detect future pandemics by unknown viruses

The biophysicists from Erlangen examined more than four million blood cells from 17 patients acutely ill with Covid-19, from 14 people who had recovered and 24 healthy people as a comparison group. They found that, for example, the size and deformability of the red blood cells of patients with the disease deviated strongly from those of healthy people. This indicates damage to these cells and could explain the increased risk of vascular occlusion and embolisms in the lungs. In addition, the oxygen supply, which is one of the main tasks of the erythrocytes, may be impaired in infected persons. Lymphocytes (one type of white blood cell responsible for the acquired immune defense) were in turn significantly softer in Covid-19 patients, which typically indicates a strong immune reaction. The researchers made similar observations for neutrophil granulocytes, another group of white blood cells involved in the innate immune response. These cells even remained drastically altered seven months after the acute infection. "We suspect that the cytoskeleton of immune cells, which is largely responsible for cell function, has changed," explains Markéta Kubánková, first author of the research article. In her view, real-time deformability cytometry has the potential to be used routinely in the diagnosis of Covid-19 -- and even to serve as an early warning system against future pandemics caused by as yet unknown viruses.

Mate choice is important for females, who often invest much more energy in offspring than males. However, being too selective is a bad idea, as they might end up not mating at all. Biologists have wondered for a long time how females optimize their chances. Scientists at the University of Groningen have performed experiments with fruit flies that reveal the explanation: mating induces a behavioural change in female flies that makes them more choosy than when they are virgins. The results were published on 21 June in Nature Ecology and Evolution.

The fourteenth-century French philosopher Jean Buridan described a donkey who starved to death because he couldn't choose between two bales of hay. Evolutionary biologists have their own version of this decision-making problem: in many species, females invest more energy in reproduction than males. Thus, males try to mate with as many females as possible, while females are choosy as they have to select the best males to father their offspring. But, like with the philosopher's donkey, being too choosy may result in no offspring at all.

Aphrodisiac

In 2005, theoretical biologists suggested an explanation: what if female species' mate preference changes over time? This would be especially beneficial for organisms like flies, who store sperm for later use and mate multiple times. 'The sperm from the last mating is favoured for fertilization, so a first mating with an inferior male is of little consequence but it does ensure that the flies can reproduce', explains Jean-Christophe Billeter, associate professor of Neurogenetics of Social and Sexual Behaviour at the University of Groningen.

The explanation sounds plausible, but is it actually true? It turned out to be difficult to prove this in a controlled experiment. Billeter: 'It is very difficult to distinguish between learned behaviour and a programmed change in mate preference.' However, Billeter and his group have ample experience in studying mating behaviour in fruit flies. And he had noted changes in the way that the flies process cues after a first mating. 'For example, food acts as an aphrodisiac - but only in females who have mated before, not in virgins.' This means that virgin and mated females pay attention to different cues. Other scientists also described differences between virgin and mated flies.

Mutations

As there are lots of lines of fruit flies with specific mutations, this model organism would allow a careful study of how mating preference is governed. Billeter and his colleagues performed a series of experiments to study mate choice. The basic set-up was to observe one female with two males, each from a different strain. These were NL (a Dutch strain) and Tai (originating from West Africa). As fruit flies mate for about twenty minutes, all it takes is to wait to see which of the two males will mount the female. 'We observed thousands of Petri dishes, often overnight, each with two male flies and one female, to get our results.'

In a first experiment, they found a very clear result: virgin flies showed no preference for NL or Tai males. But mated females became choosy; they subsequently mated with Tai males in nearly 100 per cent of the experiments. 'It was a bit of luck to find such a huge difference between the strains', says Billeter. Another series of experiments was then performed to find out how this preference came to be. A male pheromone in the sperm fluid was already known to be responsible for mating-induced changes in female behaviour. And when virgin flies mated with male mutants without pheromones, they did not become choosy. This indicated that the females were not learning to become more choosy, but, in fact, underwent a programmed physiological change leading them to become more selective.

Puzzle

As the pheromone induces the production of a substance called 'juvenile hormone' in the females, the next step was to confirm that this hormone plays a role in developing selectiveness. And indeed, virgin females that were fed this hormone developed a preference for Tai males. But how are Tai and NL males distinguished? 'We figured pheromones were involved, so we then tested females without a sense of smell. And indeed, they did not develop a preference for Tai over NL males.'

At this stage of the study, Billeter visited a conference where Chih-Ying Su from the University of California in San Diego gave a talk on pheromone receptors in fruit flies. They started a collaboration and, using electrical recordings, the Su lab showed that the Or47b Odorant receptor neurons become less sensitive to pheromones after mating, as a result of juvenile hormone signaling. 'So, we figured that the juvenile hormone reduces the sensitivity of the flies' olfactory cells to this pheromone.' The final piece of the puzzle was finding the pheromone that activates Or47b. 'This was identified, and we predicted that Tai flies would have higher levels of this aphrodisiac pheromone than NL flies.' The hypothesis was confirmed: levels in Tai males were twice as high as in NL flies. And dousing NL flies with the pheromone made them as equally attractive as the Tai males.

Ants

This leads to a clear picture: to virgins, all males smell equally lovely. But mating reduces their sensitivity for an aphrodisiac pheromone, and thus induces preference for males with higher levels of this perfume. 'We could only discover this sequence of events because fruit flies are such a powerful model system, thanks to the availability of off-the-shelf tools to manipulate neurons and behaviour', acknowledges Billeter. 'But, now that we have confirmed, in this model, that mating actually flips a switch that induces mating preferences, we expect that researchers will be able to find this in other species as well.'

And there are wider implications. 'We have now discovered a trigger that can change the behaviour of an individual by changing how it responds to a cue. The first author of the paper, postdoc Philip Kohlmeier, is an expert in social insects, such as ants and bees. He is now eager to find out if similar triggers are involved in how social insects specialize in different classes, such as foragers and nurses.'

University of Colorado Boulder researchers have discovered that minuscule, self-propelled particles called "nanoswimmers" can escape from mazes as much as 20 times faster than other, passive particles, paving the way for their use in everything from industrial clean-ups to medication delivery.

The findings, published this week in the Proceedings of the National Academy of Sciences, describe how these tiny synthetic nanorobots are incredibly effective at escaping cavities within maze-like environments. These nanoswimmers could one day be used to remediate contaminated soil, improve water filtration or even deliver drugs to targeted areas of the body, like within dense tissues.

"This is the discovery of an entirely new phenomenon that points to a broad potential range of applications," said Daniel Schwartz, senior author of the paper and Glenn L. Murphy Endowed Professor of chemical and biological engineering.

These nanoswimmers came to the attention of the theoretical physics community about 20 years ago, and people imagined a wealth of real-world applications, according to Schwartz. But unfortunately these tangible applications have not yet been realized, in part because it's been quite difficult to observe and model their movement in relevant environments--until now.

These nanoswimmers, also called Janus particles (named after a Roman two-headed god), are tiny spherical particles composed of polymer or silica, engineered with different chemical properties on each side of the sphere. One hemisphere promotes chemical reactions to occur, but not the other. This creates a chemical field which allows the particle to take energy from the environment and convert it into directional motion--also known as self-propulsion.

"In biology and living organisms, cell propulsion is the dominant mechanism that causes motion to occur, and yet, in engineered applications, it's rarely used. Our work suggests that there is a lot we can do with self-propulsion," said Schwartz.

In contrast, passive particles which move about randomly (a kind of motion known as Brownian motion) are known as Brownian particles. They're named after 19th century scientist Robert Brown, who studied such things as the random motion of pollen grains suspended in water.

The researchers converted these passive Brownian particles into Janus particles (nanoswimmers) for this research. Then they made these self-propelled nanoswimmers try to move through a maze, made of a porous medium, and compared how efficiently and effectively they found escape routes compared to the passive, Brownian particles.

The results were shocking, even to the researchers.

The Janus particles were incredibly effective at escaping cavities within the maze--as much as 20 times faster than the Brownian particles--because they moved strategically along the cavity walls searching for holes, which allowed them to find the exits very quickly. Their self-propulsion also appeared to give them a boost of energy needed to pass through the exit holes within the maze.

"We know we have a lot of applications for nanorobots, especially in very confined environments, but we didn't really know how they move and what the advantages are compared to traditional Brownian particles. That's why we started a comparison between these two," said Haichao Wu, lead author of the paper and graduate student in chemical and biological engineering. "And we found that nanoswimmers are able to use a totally different way to search around these maze environments."

While these particles are incredibly small, around 250 nanometers--just wider than a human hair (160 nanometers) but still much, much smaller than the head of a pin (1-2 millimeters)--the work is scalable. This means that these particles could navigate and permeate spaces as microscopic as human tissue to carry cargo and deliver drugs, as well as through soil underground or beaches of sand to remove unwanted pollutants.

Swarming nanoswimmers

The next step in this line of research is to understand how nanoswimmers behave in groups within confined environments, or in combination with passive particles.

"In open environments, nanoswimmers are known to display emergent behavior--behavior that is more than the sum of its parts--that mimics the swarming motion of flocks of birds or schools of fish. That's been a lot of the impetus for studying them," said Schwartz.

One of the main obstacles to reaching this goal is the difficulty involved in being able to observe and understand the 3D movement of these tiny particles deep within a material comprising complex interconnected spaces.

Wu overcame this hurdle by using refractive index liquid in the porous medium, which is liquid that affects how fast light travels through a material. This made the maze essentially invisible, while allowing the observation of 3D particle motion using a technique known as double-helix point spread function microscopy.

This enabled Wu to track three-dimensional trajectories of the particles and create visual representations, a major advancement from typical 2D modeling of nanoparticles. Without this advancement, it would not be possible to better understand the movement and behavior of either individuals or groups of nanoswimmers.

"This paper is the first step: It provides a model system and the imaging platform that enables us to answer these questions," said Wu. "The next step is to use this model with a larger population of nanoswimmers, to study how they are able to interact with each other in a confined environment."

Basic needs of disaster- and conflict-impacted refugees are often met by humanitarian relief goods and services, and until now little was known about how refugees create economic livelihood beyond immediate relief.

A new exploratory case study from Portland State University Associate Professor of Management Theodore Khoury reveals how Syrian refugees in the Za'atari camp reached beyond basic disaster relief support and leveraged social capital to create informal economic systems that helped improve their quality of life. The study, "Towards a theory of informal supply networks: An?exploratory case study of the Za'atari refugee camp," is published in the Journal of Operations Management and co-authored by Ismail Abushaikha of German-Jordanian University and Zhaohui Wu of Oregon State University.

The ongoing Syrian civil war started in March 2011. Between 2012 and 2018, nearly a half million Syrian refugees passed through the Za'atari refugee camp, the world's second largest refugee camp, located in Jordan just 6 km southwest of the Syrian border. In one of the first case studies of its kind, interviews, observation data, field notes, photos and videos collected in and around Za'atari uncovered complex, refugee-led, informal supply networks that contribute to the resilience of the camp and also benefit Mafraq, the Jordanian host community.

The study dispels the notion of refugees as passive aid recipients awaiting charity, and instead asserts a refugee camp as a society with complex social systems.

"Many refugees reside in camps indefinitely and refugee regimes overlook or are incapable of supporting their development needs and ability to prosper socially and find a durable economic livelihood," says Khoury. "When a formal economy is unavailable or fails to include them, informal economies can evolve to serve them and meet these needs."

Given its city-like settings and energetic marketplaces, Za'atari is often profiled as a "success story" in the media and by relief organizations and donor countries. The researchers conducted 52 interviews, speaking with refugees, non-governmental and intergovernmental organizations (NGO and IGO) workers, Mafraq community members, and government officials. The research findings develop a theory of informal supply networks, or an aggregate of predominantly illicit -- yet legitimate -- channels and social relationships that support the economic exchange of goods and services between distinct actors or actor groups; in this case those represented by the interviewees.

"Our theory of informal supply networks offers a new approach to thinking about mass migration and refugee integration," says Khoury. "By understanding social behavior in an extreme context, we can develop more flexible humanitarian relief policy and operations that give refugees agency to create their future through economic exchange."

Supply networks started to emerge when refugees engaged in improvised, secondhand transactions, buying and selling donated relief goods among themselves and with Mafraq residents. Relief goods were also repurposed as new production materials. Refugees in Za'atari coordinated access to critical goods that fell outside the scope of relief-related activities and adopted roles of buyers, suppliers, distributors, wholesalers, retailers, traffickers and service providers. Over time, the formal and informal economic activities of all actors gave shape to the supply networks in the camp.

Three informal supply networks -- building materials and housing, electricity and electrical hardware, and food and goods -- were the case study's focus because products and services associated were critical in meeting the basic needs of refugees and therefore had practical implications for the daily lives of refugees; formal relief operations and refugee-initiated informal operations interacted to support the flow of resources in these networks; and these networks were representative of economic activities involving refugees.

The researchers captured the economic activity of each supply network by mapping the flow of materials with actor social activity and relationships. The mapping revealed where transactions occurred and in what direction; the nature of transactions were not always simple or even obvious. Three key insights led to a more critical assessment of the emergency-oriented, formal relief operations and compelled a refugee point of view:

Social ties created prior to the conflict sometimes existed between refugees and merchants or intermediaries within Mafraq, giving some refugees access to resources that others did not have

Governance for specific transactions was unique depending on the kind of goods being exchanged

Representatives of the camp authority, like security guards, routinely tolerated trafficking, recognizing the mutual development support to the host community

Data collection and network mapping uncovered three theoretical dimensions, which delineated the transactions -- and their functioning -- within the informal supply networks:

Positioning of unique social capitals: Social capital is defined as "resources embedded in one's social networks, [and] resources that can be accessed or mobilized through ties in the networks (Lin, 2008, p. 51)." Bonding, bridging and linking represent the three forms of social capital or relationship ties. Bonding accounts for ties that are more familiar, like family, friends and neighbors. Bridging connects actors in parallel networks, like other neighborhoods, clans and social groups. Linking captures ties characterized by differences in power distance, social status or hierarchy. The three forms of social capital defined the boundaries of Za'atari informal supply networks and also expanded boundaries beyond the borders of the camp -- they enabled efficient economic exchanges and cultivated trusting relationships that led to resilient supply networks.

"In 2013, the refugees used to take some of the care packages and sell them in Mafraq stores [...] and buy other things that they needed, so now there is money generating in the camp and in the same time Syrian women started making food and started selling them to the employees and staff of NGOs." (Supply Chain Officer, UNHCR, 2016)

"I used to work in plumbing and now I have a dairy shop [in the market street]. Once one of my friends who owns a restaurant asked me if I could bring chicken drumsticks and I got 15 kilograms of them and they were sold within 3 minutes." (Dairy Products Seller, Refugee, 2016)

Governance of transactions according to specific conventions: The camp's informal economy with supply networks were all linked to the formal relief networks governed by explicit rules and policies and managed through a hierarchy: the Jordanian government entrusted camp management under UNHCR (United Nations High Commissioner for Refugees), which in turn coordinated relief operations of other NGOs/IGOs like Portland-based Mercy Corps. In contrast, the informal supply networks were self-organized and transactions were governed by either culturally- or market-guided conventions. For example, electricity followed market-guided conventions under skilled refugees and a fee-for-service model. Building materials and housing supplies were a combination of both, where community leaders prioritized family members and others with preferential relationships while at the same time materials were sold through a profit-driven underground market agnostic to who purchased.

"Refugees in Azraq Camp [in Jordan] are forced to go to the shopping malls [World Food Program Supermarkets] to buy their goods, which is very expensive, but, here [at the Za'atari refugee camp], we have more options in the market to buy from." (Perfume Shop Owner, Refugee, 2016)

"Bikes from some donors were also distributed at some point and some of them [refugees] got more than necessary and then they sold them. Bikes are a major business in Mafraq now as it is widely used in the city of Mafraq and the camp as well." (Supermarket Cashier, Host Community, 2018)

Legitimation of refugee-initiated economic activities: Camp security guards, often hired locally from Mafraq, felt that the citizens of Mafraq also deserved access to relief supplies; they favored the interests of refugees and locals over law enforcement, since they often came from standards of living that were at or below the level of some refugees. This stance translated into a more permeable or flexible camp border in terms of the kinds of goods that could cross the camp boundary. As a result, guards, as representatives of the camp authority, did not consistently stop the trafficking of goods across the camp border and allowed informal supply networks, as well as the traffickers inside and across the camp boundary, to be legitimated. The Jordanian government and camp authorities recognized that this informality helped sustain the livelihoods of refugees, bring positive economic opportunities to Mafraq and reduce conflict in the camp.

"There are not contracts between the owners of the caravans and the users of the caravans [...]. We don't intervene in organizing the market. We intervene if there is a complaint by others. Although this is illegal [selling and renting caravans], as long as there are no complaints, or this is not making troubles for others we don't intervene." (Community Police Officer #2, Government, 2016)

"They [donkeys and sheep] are allowed but we cannot bring them through the camp's main gate. It is not allowed to bring them legally, but once we have them inside the camp, it is ok." (Bedouin Refugee, 2017)

"The situations faced by refugees are beyond difficult and life in Za'atari is a far cry from the life they were forced to leave behind," says Khoury.

The study brings to light that the international policies on refugees and refugee regimes are outdated. Created shortly after WWII, these policies are poorly structured to handle large scale migration as has been seen today in Europe and Southern Asia. The study suggests that given prolonged stays in "permanent temporariness," humanitarian relief operations and host communities need to approach the condition of the refugee camp with longer term solutions in mind.

"When we value the dignity and human agency of refugees and allow for their cultural and social capital to be asserted on their terms, communities can flourish," adds Khoury. "With more thought invested into how refugees can be welcomed and integrated into communities, perhaps we can begin to shift the migration discourse into opportunities for positive social change, rather than ongoing situations of 'crisis.'"

PHILADELPHIA - The use of e-cigarettes, or vaping, causes serious damage to the lungs. After the novel coronavirus responsible for the respiratory disease COVID-19 emerged last year, there have been ongoing concerns about how vaping might impact risk of infection and severity of symptoms. Some evidence shows an increased risk of COVID-19 among those who vape. Research also shows a higher COVID-19 mortality rate in men compared to women, and men are more likely to vape than women. However, there is no evidence to link these two observations.

New research from Jefferson sheds light on this by showing that exposure to e-cigarette vapor increases levels of the coronavirus receptor in the lungs of male mice, particularly when nicotine is present in the vapor. This could make it easier for the virus to infect. The findings were published in Journal of Investigative Medicine on April 29.

Using the spike-like protein on its surface like a key, the novel coronavirus binds to the angiotensin-converting enzyme 2 (ACE-2) receptor found in the lining of our airways, and unlocks its path into our lung cells.

"It's been shown that cigarette smokers have higher levels of ACE-2 in their lungs and that smoking is a known risk factor for developing lung disease and infection," says Pawan Sharma, PhD and co-senior author of the study. "We wanted to see if a similar effect is seen with e-cigarettes or vaping, and whether any effects observed are different between male and females."

The researchers housed female or male mice in a box attached to an automated system that delivered precisely controlled amounts of e-cigarette vapor, with or without nicotine, for 30 min, twice a day for 21 days. Compared to control mice that breathed room air, mice exposed to e-cigarette vapor had inflammation of their lung tissue and reduced lung function, confirming the dangers of vaping. These effects were observed whether or not nicotine was added to the vapor, pointing to the inherently harmful nature of the chemicals found in e-cigarette vapor.

There was also an increase in the levels of the ACE-2 receptor in the lungs of vapor-exposed mice, male and female. Though this was not tested in the current study, higher levels of ACE-2 receptor could make it easier for the virus to enter the airways, increasing susceptibility to infection.

Interestingly, the presence of nicotine in the vapor further enhanced the increase in ACE-2 specifically in male mice.

The researchers are the first to demonstrate this potential sex-difference in the effect of vaping and nicotine exposure on ACE-2 levels in vivo. Though further research is needed to understand the complexity of risk factors for COVID-19, this result sheds light on important physiological differences that make one sex potentially more vulnerable.

"Our findings provide rationale for looking at the effect of vaping on ACE-2 levels in the lungs of humans," says Dr. Sharma. "If a similar induction of ACE-2 is seen, it provides further evidence for vaping being a risk factor for COVID-19 and can help us understand how to prevent and mitigate infection in this population."

RICHLAND, Wash.--Researchers have increased the lifetime of a promising electric vehicle battery to a record level, an important step toward the goal of lighter, less expensive and long-lasting batteries for future electric vehicles. The work is reported June 28 in the journal Nature Energy.

Such batteries--the goal of research groups the world over--are seen as an important part of the solution to reduce the effects of climate change, and scientists are exploring a dizzying array of options.

One solution on the horizon is a lithium-metal battery for electric vehicles. These batteries hold almost twice the energy of their widely used lithium-ion counterparts, and they're lighter. That combination offers the enticing prospect of an electric vehicle that would be lighter and go much farther on a single charge. But lithium-metal batteries in the laboratory have been plagued by premature death, lasting only a fraction of the time of today's lithium-ion batteries.

Now, a team of scientists at the U.S. Department of Energy's Pacific Northwest National Laboratory has created a lithium-metal battery that lasts for 600 cycles, far longer than other reported results. That means it can be fully charged and discharged 600 times before it dies.

It's a big step forward for a promising technology, but lithium-metal technology is not yet ready for prime time. While the lithium-ion batteries used in electric vehicles today hold less energy, they last longer, typically at least 1,000 cycles. But vehicles won't go as far on one charge as they would with an effective lithium-metal battery.

The new research was done through DOE's Innovation Center for Battery500 Consortium, a multi-institution effort led by PNNL to develop electric vehicle batteries that are lighter, more energy intensive and less expensive than those currently used. PNNL leads the consortium and is responsible for integrating the latest advances from partner institutions into devices known as high-energy pouch cells and demonstrating improved performance under realistic conditions.

Lithium metal: Thin strips of lithium translate to longer lifetime

The PNNL team found a way to increase the battery's lifetime by taking a surprising approach. Instead of using anodes with more lithium, the team used incredibly thin strips of lithium, just 20 microns wide, far thinner than the width of a human hair.

"Many people have thought that thicker lithium would enable the battery to cycle longer," said Jie Xiao, who along with Jun Liu, the director of the Battery500 Consortium, is a corresponding author of the paper. "But that is not always true. There is an optimized thickness for each lithium-metal battery depending on its cell energy and design."

The lithium-metal battery created by the Battery500 team has an energy density of 350 watt-hours per kilogram (Wh/kg)--very high but not unprecedented. The value of the new findings has more to do with the battery's lifetime. After 600 cycles, the battery retained 76 percent of its initial capacity.

Just four years ago, an experimental lithium-metal battery could operate for 50 cycles. That has increased rapidly; two years ago the PNNL team achieved 200 cycles--and now 600. Moreover, the PNNL battery is a pouch cell, which more closely mirrors real-world conditions than does a coin cell, a less realistic type of device used in many battery research projects.

Lithium metal: Why thickness matters

The team's decision to try thinner lithium strips was based on its detailed understanding of the molecular dynamics of the anode as explained in the Nature Energy paper.

The scientists found that thicker strips contribute directly to battery failure. That's due to complex reactions around a film on the anode known as the solid electrolyte interphase, or SEI. The SEI is the byproduct of side reactions between lithium and the electrolyte. It acts as an important gatekeeper that allows certain molecules to go from the anode to the electrolyte and back again while keeping other molecules at bay.

It's an important job. An SEI working effectively allows certain lithium ions to pass through but limits unwanted chemical reactions that reduce battery performance and accelerate cell failure. A primary goal for researchers has been to reduce unwanted side reactions between the electrolyte and the lithium metal--to encourage vital chemical reactions while restraining unwanted ones.

The team found that thinner lithium strips are adept at creating what one might call good SEI, while the thicker strips have a higher chance of contributing to what one might call harmful SEI. In their paper, the researchers use the terms "wet SEI" and "dry SEI." The wet version retains contact between the liquid electrolyte and the anode, making important electrochemical reactions possible.

But in the dry version, the liquid electrolyte doesn't reach all of the lithium. Simply, because the lithium strips are thicker, the electrolyte needs to flow into deeper pockets of the lithium, and as it does so, it leaves other portions of the lithium dry. This stops important reactions from occurring, effectively smothering necessary electrochemical reactions, and contributes directly to the early death of the battery.

It's an important issue, especially in realistic batteries like pouch cells, where the amount of electrolyte available is 20 to 30 times less than that used in experimental coin cells.

Consider how a frying pan gradually builds up a layer of grease if not cleaned thoroughly after each time it is used. Over time, the layer builds up and acts as a barrier, reducing the flow of energy and making the surface less effective. In the same way, an unwanted, dry SEI layer prevents the effective transfer of energy needed inside a battery.

Progress thanks to Battery500

The progress on lithium-metal batteries has been substantial, thanks to the Battery500 Consortium. The goal is to increase the amount of energy packed into a long-duration, safe, affordable battery. More energy per pound of material translates to a lighter vehicle that can go farther on one charge. Today's electric vehicle batteries are in the neighborhood of 200-250 Wh/kg; Battery500 is aiming for a cell level of 500 Wh/kg.

"The Battery500 Consortium has made great progress in increasing the energy density and extending the cycle life," said Distinguished Professor M. Stanley Whittingham of Binghamton University, the 2019 Nobel Prize laureate in chemistry and a coauthor of the paper. "But much more needs to be done. In particular, there are safety issues with lithium-metal batteries that must be addressed. That's something that the Battery500 team is working hard to resolve."

(San Antonio, June 29, 2021) - UTSA criminology and criminal justice professors Michael R. Smith and Rob Tillyer working in collaboration with University of Cincinnati Professor Robin Engel examined racial and ethnic disparities in the use of force by the Fairfax County Police Department (FCPD). One of the nation's largest county police departments, the FCPD serves Fairfax County, Va., a major metropolitan county near Washington, D.C.

The team presented the results of its 18-month study today to the Public Safety Committee of the Fairfax County Board of Supervisors. The team analyzed three years of data, including 1,360 cases of force used by FCPD officers against at least one civilian between January 1, 2016 and December 31, 2018.

In addition to investigating the influence of civilian race, ethnicity and other factors on force used by FCPD officers, the team also was charged with providing recommendations for reducing potential bias in officer decision-making and improving future use of force data collection.

"Last year highlighted the racial and social disparities that are a fact of life for many in the U.S. The protests following the killing of George Floyd, public health disparities highlighted by the COVID-19 pandemic, and rising violent crime in many cities are examples of the larger social and economic challenges we face," said Smith. "As an urban serving university, UTSA is committed to research that can address the nation's pressing challenges."

Using benchmarks to compare the rate of force used against racial and ethnic subgroups to the expected risk of force across those groups, the researchers also used a series of multivariate regression models to assess factors associated with the totality and severity of force used used against civilians in Fairfax County.

The researchers benchmarked force used against the major racial and ethnic groups in Fairfax County to the racial and ethnic composition of criminal suspects and arrestees in the county. Key findings of the study included:

Average force levels were slightly higher for Blacks (2.4 on a 4.0 scale) than for other racial groups while resistance levels were essentially equal across the racial and ethnic groups.

The rates of force used against White and Black civilians consistently exceeded the benchmarks while Hispanic civilians were underrepresented in force cases compared to the benchmarks. The benchmarking findings for Asian civilians were mixed with some showing overrepresentation and some not.

Comparing rates of force used against minorities relative to Whites utilizing these same benchmarks showed that in all but one case, the rate of force used against minorities was lower than the rate used against Whites.

At the same time, Black, and to a lesser degree Hispanic civilians, experienced more severe force than Whites, and those findings varied by district station.

The researchers concluded that force was used county-wide more often than expected against White and Black civilians based on the benchmark comparisons and generally less often than expected against Hispanic civilians. They also found that Black civilians were more likely to have force used against them in arrest situations compared to Whites.

The researchers offered the FCPD many constructive suggestions on how to enhance its data collection practices, improve its use of force policies and provide evidence-based training to officers to help reduce future disparities in the use of force.

"The Fairfax County Police Department is one of the leading law enforcement agencies in the country. We hope our findings provide the agency and the residents of Fairfax County with a roadmap for improvement," said Smith.

HOUSTON - (June 29, 2021) - When you think about trade and market relationships, you might think about brokers yelling at each other on the floor of a stock exchange on Wall Street. But it seems one of the basic functions of a free market is quietly practiced by fungi.

New research from a Rice University economist suggests certain networks of fungi embrace an important economic theory as they engage in trading nutrients for carbon with their host plants. This finding could aid the understanding of carbon storage in soils, an important tool in mitigating climate change.

A research paper entitled "Walrasian equilibrium behavior in nature" is available online and will appear in an upcoming edition of Proceedings of the National Academy of Sciences. Ted Loch-Temzelides, a professor of economics and the George and Cynthia Mitchell Chair in Sustainable Development at Rice, examined through an economic lens data from ecological experiments on arbuscular mycorrhizal fungi networks, which connect to plants and facilitate the trading of nutrients for carbon.

Loch-Temzelides found that these relationships resemble how economists think about competitive - also known as Walrasian - markets. The paper demonstrates that Walrasian equilibrium, a leading concept in the economic theory of markets used to make predictions, can also be used to understand trade in this "biological market."

"Far from being self-sacrificing, organisms such as fungi can exhibit competitive behavior similar to that in markets involving sophisticated human participants," Loch-Temzelides said.

His finding also implies that resources are allocated to the maximum benefit of the market participants -- in this case, fungi and plants.

"Mycorrhizal fungi networks around the world are estimated to sequester around 5 billion tons of carbon per year," Loch-Temzelides said. "Manipulating the terms of trade so that carbon obtained from host plants becomes less expensive compared to nutrients could lead to additional carbon being stored in the soil, which could provide major benefits in fighting climate change."

Loch-Temzelides hopes future research by biologists and economists can make progress on better understanding these interactions.

Among low-income, uninsured, or publicly insured women ages 25-64 years who were not up to date on cervical cancer screening, 72% perceived financial barriers to screening. The most commonly reported barriers were screening appointment costs (71%) and follow-up/future treatment costs (44%), according to a study published in the peer-reviewed Journal of Women’s Health. Click here to read the article now.

Screening is effective at reducing the incidence of and mortality associated with cervical cancer. However, disparities exist in cervical cancer incidence and mortality and in cervical cancer screening based on poverty level, insurance status, race, and ethnicity. Only about 64% of uninsured women, 78% of publicly insured women, and 75% of low-income women have been screened in accordance with national screening guidelines. Perceived financial barriers to screening likely affect cervical cancer screening adherence.

“Most notably, this study illustrates the importance of the availability and awareness of health. Insurance and other financial resources to reduce perceived financial barriers to screening,” state Jennifer Smith, PhD, University of North Carolina, and coauthors of the study. “Insurance status heavily influences the actual out-of-pocket costs incurred from the cervical cancer screening appointment and labs, which may influence perceived cost burden and barriers.”

“Low-income women need greater access to insurance coverage options, Medicaid eligibility, or free screening programs so they can undergo regular cervical cancer screening without perceived financial barriers to care,” says Journal of Women’s Health Editor-in-Chief Susan G. Kornstein, MD, Executive Director of the Virginia Commonwealth University Institute for Women’s Health, Richmond, VA.

Boulder, Colo., USA: Article topics include the Great Unconformity of the
Rocky Mountain region; new Ediacara-type fossils; the southern Cascade arc
(California, USA); the European Alps and the Late Pleistocene glacial
maximum; Permian-Triassic ammonoid mass extinction; permafrost thaw; the
southern Rocky Mountains of Colorado (USA); “gargle dynamics”; invisible
gold; and alluvial fan deposits in Valles Marineris, Mars. These Geology articles are online at

https://geology.geoscienceworld.org/content/early/recent

.

A new kind of invisible gold in pyrite hosted in deformation-related
dislocations

Denis Fougerouse; Steven M. Reddy; Mark Aylmore; Lin Yang; Paul Guagliardo
...

Abstract:
Mining of “invisible gold” associated with sulfides in gold ores represents
a significant proportion of gold production worldwide. Gold hosted in
sulfide minerals has been proposed to be structurally bound in the crystal
lattice as a sulfide-gold alloy and/or to occur as discrete metallic
nanoparticles. Using a combination of microstructural quantification and
nanoscale geochemical analyses on a pyrite crystal from an orogenic gold
deposit, we show that dislocations hosted in a deformation low-angle
boundary can be enriched in Ni, Cu, As, Pb, Sb, Bi, and Au. The cumulative
trace-element enrichment in the dislocations is 3.2 at% higher compared to
the bulk crystal. We propose that trace elements were segregated during the
migration of the dislocation following the dislocation-impurity pair model.
The gold hosted in nanoscale dislocations represents a new style of
invisible gold.

View article
:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G49028.1/604581/A-new-kind-of-invisible-gold-in-pyrite-hosted-in

A quantification of the effect of diagenesis on the paleoredox record
in mid-Proterozoic sedimentary rocks

Alec M. Hutchings; Alexandra V. Turchyn

Abstract:
Iron speciation in ancient sedimentary rocks is widely used to reconstruct
oceanic redox conditions over geological time, specifically to assess the
extent of oxic, euxinic (anoxic containing sulfide), and ferruginous
(anoxic containing iron) conditions. We explore how post-depositional
sedimentary processes can skew particular geochemical signals in the rock
record. One such process is when aqueous sulfide—including that produced in
the sediment column—reacts with sedimentary iron, converting non-sulfide,
highly reactive iron minerals to iron-sulfide minerals; this can lead to
increased preservation of iron as pyrite and an overestimation of seafloor
euxinia. We show that sedimentary rocks with higher (>5 wt%) total iron
content are more buffered to this effect and thus are a more reliable
indicator of true water-column euxinia. When considering this effect in the
geological past, we estimate that true euxinia in the mid-Proterozoic may
have been as much as fourfold less than previously thought—more in line
with other recent paleoredox proxies not based on iron minerals. Marine
iron and sulfate concentrations were more equivalent in
Proterozoic–Neoproterozoic oceans, suggesting this time period was
particularly susceptible to this post-depositional alteration, explaining
the extent of euxinia suggested for this geological interval.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48774.1/604580/A-quantification-of-the-effect-of-diagenesis-on

How fast do submarine fans grow? Insights from the Quaternary Golo
fans, offshore Corsica

Michael L. Sweet; Gwladys T. Gaillot; Tammy M. Rittenour; Kathrine Love;
Michael D. Blum

Abstract:
High-resolution seismic, core, and chronological data from the Quaternary
Golo deep-sea fans, offshore Corsica, France, give new insights into rates
of submarine fan growth. Average vertical deposition rates for units that
represent the Late Pleistocene glacial periods are 0.1–0.5 m/k.y.
Glacial-age deposits are sand rich; in contrast, post-glacial deposits lack
a significant sand fraction and are dominated by carbonate-rich mud. As a
result, seismically constrained volumetric rates of deposition for glacial
periods with low sea level and a subaerially exposed shelf are ~0.23 km 3/k.y., 2×–5× higher than rates during interglacials when sea
level is high, the shelf is submerged, and sand is trapped in
shallow-marine environments. At millennial time scales, variations in
deposition rate reflect climate-driven sea-level changes, autogenic
avulsion of river channels that extend across the shelf during low sea
level, and autogenic avulsion of submarine channels that shift the locus of
deposition laterally. Short-term deposition rates range from 8.6 m/k.y. at
proximal portions of submarine fans to 0.4 m/k.y. along the distal fringe.
Our data show that submarine fans can be dynamic environments with
formation and evolution of levee-confined channels and lobe complexes in 10 3–104 yr, comparable to the time scales needed to
form fluvial channel belts and delta lobes.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48911.1/604582/How-fast-do-submarine-fans-grow-Insights-from-the

Contrasting northern and southern European winter climate trends during
the Last Interglacial

J. Sakari Salonen; Maria Fernanda Sánchez-Goñi; Hans Renssen; Anna Plikk

Abstract:
The Last Interglacial (LIG; 130–115 ka) is an important test bed for
climate science as an instance of significantly warmer than preindustrial
global temperatures. However, LIG climate patterns remain poorly resolved,
especially for winter, affected by a suite of strong feedbacks such as
changes in sea-ice cover in the high latitudes. We present a synthesis of
winter temperature and precipitation proxy data from the Atlantic seaboard
of Europe, spanning from southern Iberia to the Arctic. Our data reveal
distinct, opposite latitudinal climate trends, including warming winters
seen in the European Arctic while cooling and drying occurred in southwest
Europe over the LIG. Climate model simulations for 130 and 120 ka suggest
these contrasting climate patterns were affected by a shift toward an
atmospheric circulation regime with an enhanced meridional pressure
gradient and strengthened midlatitude westerlies, leading to a strong
reduction in precipitation across southern Europe.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G49007.1/604583/Contrasting-northern-and-southern-European-winter

A record of syn-tectonic sedimentation revealed by perched
alluvial fan deposits in Valles Marineris, Mars

J.M. Davis; P.M. Grindrod; S.G. Banham; N.H. Warner; S.J. Conway ...

Abstract:
On Mars, basins formed by tectonic processes are rare and mostly have
unconstrained subsidence histories. One method for understanding this
record of subsidence is through associated alluvial fans, which are sourced
from uplifted areas and accumulate in downthrown basins. The source,
morphology, and superposition of fan deposits can be used to reconstruct
fault kinematics, the relative timing of accommodation space formation,
and, in turn, the influence tectonic processes had on Martian fan
formation. Here we use high-resolution orbital data sets to characterize
sediment fan deposits associated with syn-tectonic sedimentation in two
regions of the Valles Marineris canyons: Coprates Chasma and Juventae
Chasma. These deposits comprise sediment fans on the current canyon floor
and low-gradient surfaces perched several kilometers above the canyon
floor. We interpret the low-gradient surfaces as remnant sediment fan
deposits, which originally formed at the former canyon floor and have since
been offset due to normal faulting. The preservation of vertically offset
generations of sediment fan deposits supports a progressive, basinward
migration of fault activity into the original hanging wall or repeat
activity along a fault zone. Each episode of faulting was followed by a
basinward shift in drainages, which led to fault-scarp degradation and
formation of a new generation of fans. Multiple episodes of syn-tectonic
sedimentation occurred during the evolution of the basins, with fluvial
activity sporadically active. Our results demonstrate, for the first time
on Mars, that depositional cyclicity was linked to tectonic deformation,
possibly representative of regional processes throughout Valles Marineris.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48971.1/604584/A-record-of-syn-tectonic-sedimentation-revealed-by

Seismic fault weakening via CO2 pressurization enhanced by
mechanical deformation of dolomite fault gouges

Hyun Na Kim; Byung-Dal So; Min Sik Kim; Kee Sung Han; Sol Bi Oh

Abstract:
Carbon dioxide emissions from dolomite decarbonation play an essential role
in the weakening of carbonate faults by lowering the effective normal
stress, which is thermally activated at temperatures above 600–700 °C.
However, the mechanochemical effect of low-crystalline ultrafine fault
gouge on the decarbonation and slip behavior of dolomite-bearing faults
remains unclear. In this study, we obtained a series of artificial dolomite
fault gouges with systematically varying particle sizes and dolomite
crystallinities using a high-energy ball mill. The laboratory-scale
pulverization of dolomite yielded MgO at temperatures below 50 °C,
indicating that mechanical decarbonation without significant heating
occurred due to the collapse of the crystalline structure, as revealed by
X-ray diffraction and solid-state nuclear magnetic resonance results.
Furthermore, the onset temperature of thermal decarbonation decreased to
~400 °C. Numerical modeling reproduced this two-stage decarbonation, where
the pore pressure increased due to low-temperature thermal decarbonation,
leading to slip weakening on the fault plane even at 400–500 °C; i.e.,
200–300 °C lower than previously reported temperatures. Thus, the presence
of small amounts of low-crystalline dolomite in a fault plane may lead to a
severely reduced shear strength due to thermal decomposition at ~400 °C
with a small slip weakening distance.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48938.1/604585/Seismic-fault-weakening-via-CO2-pressurization

Alpine relief limited by glacial occupation time

Bernhard Salcher; Günther Prasicek; Sebastian Baumann; Florian Kober

Abstract:
Glaciers exert a major control on the shape of mountain topography. They
tend to reduce relief above and scour troughs below the equilibrium line
altitude (ELA). While many studies report this dichotomy, relief-limiting
effects are controversial due to difficulties in quantifying key factors
such as the initial topography, the timing of glacial occupancy, or rock
uplift counteracting glacial erosion. Consequently, effectivity and degree
of glacial erosion remain ambiguous. In geologically and climatically
well-investigated parts of the European Central Alps, our calculation of
glacial occupation time (GOT) from Quaternary ELA variations allows the
quantification of gradual topographic modifications generated by the
cumulative impact of cirque erosion over the Quaternary. We show that under
low uplift, relief is effectively limited by glacial and periglacial
headwall retreat, leading to a decline in topographic relief as GOT
increases. Conversely, higher uplift rates seem to induce more persistent
valley glaciation, triggering a positive feedback loop in which steep
slopes are protected against erosion and relief increases.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48639.1/604586/Alpine-relief-limited-by-glacial-occupation-time

Spatially variable provenance of the Chinese Loess Plateau

Haobo Zhang; Junsheng Nie; Xiangjun Liu; Alex Pullen; Guoqiang Li ...

Abstract:
Loess sequences of the Chinese Loess Plateau (CLP) compose one of the most
complete Neogene–Quaternary terrestrial paleoclimatic archives.
Understanding the CLP’s sediment sources is critical to tracing Asian
aridification, atmospheric circulation patterns, and Asian monsoon
evolution. Commonly, the sediments that compose the Quaternary strata of
the CLP are considered largely homogeneous, and thus numerous studies have
applied a uniform source model when attempting to use CLP-derived proxies
as paleoclimate indicators. Here we present large-n detrital
zircon U-Pb geochronology data from the Quaternary CLP. These data support
spatial variability in sediment provenance across the CLP. At least three
distinct provenance zones are recognized for Quaternary loess strata:
central western, eastern, and northeastern. These zones received sediment
primarily from their neighboring river systems. This finding conflicts with
the classic views that attribute the Quaternary loess principally to the
deserts north and west of the CLP. We conclude that fluvial processes, and
thus precipitation, played an important and previously underemphasized role
in Quaternary dust production in northern China. Furthermore, nonuniformity
in CLP Quaternary sediment provenance raises questions about the validity
of using paleoclimate information archived in the CLP to make sweeping
regional interpretations.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48867.1/604587/Spatially-variable-provenance-of-the-Chinese-Loess

Igneous rock area and age in continental crust

Shanan E. Peters; Craig R. Walton; Jon M. Husson; Daven P. Quinn; Oliver
Shorttle ...

Abstract:
Rock quantity and age are fundamental features of Earth’s crust that
pertain to many problems in geoscience. Here we combine new estimates of
igneous rock area in continental crust from the Macrostrat database
(https://macrostrat.org/) with a compilation of detrital zircon ages in
order to investigate rock cycling and crustal growth. We find that there is
little or no decrease in igneous rock area with increasing rock age.
Instead, igneous rock area in North America exhibits four distinct
Precambrian peaks, remains low through the Neoproterozoic, and then
increases only modestly toward the recent. Peaks in Precambrian detrital
zircon age frequency distributions align broadly with peaks in igneous rock
area, regardless of grain depositional age. However, detrital zircon ages
do underrepresent a Neoarchean peak in igneous rock area; young grains and
ca. 1.1 Ga grains are also overrepresented relative to igneous area.
Together, these results suggest that detrital zircon age distributions
contain signatures of continental denudation and sedimentary cycling that
are decoupled from the cycling of igneous source rocks. Models of
continental crustal evolution that incorporate significant early increase
in volume and increased sedimentation in the Phanerozoic are well supported
by these data.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G49037.1/604588/Igneous-rock-area-and-age-in-continental-crust

Explosive caldera-forming eruptions and debris-filled vents: Gargle
dynamics

Greg A. Valentine; Meredith A. Cole

Abstract:
Large explosive volcanic eruptions are commonly associated with caldera
subsidence and ignimbrites deposited by pyroclastic currents. Volumes and
thicknesses of intracaldera and outflow ignimbrites at 76 explosive
calderas around the world indicate that subsidence is commonly simultaneous
with eruption, such that large proportions of the pyroclastic currents are
trapped within the developing basins. As a result, much of an eruption must
penetrate its own deposits, a process that also occurs in large,
debris-filled vent structures even in the absence of caldera formation and
that has been termed “gargling eruption.” Numerical modeling of the
resulting dynamics shows that the interaction of preexisting deposits
(fill) with an erupting (juvenile) mixture causes a dense sheath of fill
material to be lifted along the margins of the erupting jet. This can cause
an eruption that would otherwise produce a buoyant plume and fallout
deposits to instead form pyroclastic currents as the dense sheath drives
pulsing jet behavior. Increasing thickness of fill amplifies the time
variation in jet height. Increasing the fill grain size relative to that of
the juvenile particles can result in a much higher jet due to poorer mixing
between the dense sheath and the dilute jet core. In all cases, material
collapses along the entire height of the dense sheath rather than from the
top of a simple fountain. These gargle dynamics provide strong backing for
processes that have been inferred to result in intraplinian ignimbrites and
simultaneous deposition from high- and low-energy pyroclastic currents.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48995.1/604589/Explosive-caldera-forming-eruptions-and-debris

Prior oil and gas production can limit the occurrence of
injection-induced seismicity: A case study in the Delaware Basin of
western Texas and southeastern New Mexico, USA

Noam Z. Dvory; Mark D. Zoback

Abstract:
We demonstrate that pore pressure and stress changes resulting from several
decades of oil and gas production significantly affect the likelihood of
injection-related induced seismicity. We illustrate this process in the
Delaware Basin (western Texas and southeastern New Mexico, USA), in which
hydraulic fracturing and waste-water injection have been inducing numerous
earthquakes in the southernmost part of the basin where there has been no
prior oil and gas production from the formations in which the earthquakes
are now occurring. In the seismically quiescent part of the basin, we show
that pore-pressure and poroelastic-stress changes associated with prior oil
and gas production make induced seismicity less likely. The findings of
this study have important implications for the feasibility of large-scale
carbon storage in depleted oil and gas reservoirs.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G49015.1/604590/Prior-oil-and-gas-production-can-limit-the

Excess ice loads in the Indian Ocean sector of East Antarctica during
the last glacial period

Takeshige Ishiwa; Jun’ichi Okuno; Yusuke Suganuma

Abstract:
An accurate reconstruction of the Antarctic Ice Sheet is essential in order
to develop an understanding of ice-sheet responses to global climate
changes. However, the erosive nature of ice-sheet expansion and the
difficulty of accessing much of Antarctica make it challenging to obtain
field-based evidence of ice-sheet and sea-level changes before the Last
Glacial Maximum. Limited sedimentary records from Lützow-Holm and Prydz
Bays in East Antarctica demonstrate that the sea level during Marine
Isotope Stage 3 was close to the present level despite the global sea-level
drop lower than –40 m. We demonstrate glacial isostatic adjustment modeling
with refined Antarctic Ice Sheet loading histories. Our experiments reveal
that the Indian Ocean sector of the Antarctic Ice Sheet would have been
required to experience excess ice loads before the Last Glacial Maximum in
order to explain the observed sea-level highstands during Marine Isotope
Stage 3. As such, we suggest that the Antarctic Ice Sheet partly reached
its maximum thickness before the global Last Glacial Maximum.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48830.1/600851/Excess-ice-loads-in-the-Indian-Ocean-sector-of

Across-arc variations in Mo isotopes and implications for subducted
oceanic crust in the source of back-arc basin volcanic rocks

Xiaohui Li; Quanshu Yan; Zhigang Zeng; Jingjing Fan; Sanzhong Li ...

Abstract:
Molybdenum (Mo) isotope ratios provide a potential means of tracing
material recycling involved in subduction zone processes. However, the
geochemical behavior of Mo in subducted oceanic crust remains enigmatic. We
analyzed Mo isotope ratios of arc and back-arc basin lavas from the Mariana
subduction zone (western Pacific Ocean), combining newly obtained element
and Sr-Nd-Pb-Li isotope data to investigate subduction zone geochemical
processes involving Mo. The Mo isotope ratios (δ98/95Mo NIST3134; U.S. National Institute of Standards and Technology
[NIST] Mo standard) of the volcanic rocks showed clear across-arc
variations, decreasing with increasing depth to the Wadati-Benioff zone.
The high δ98/95Mo values in the Mariana Islands (–0.18‰ to
+0.38‰) correspond to high 87Sr/86Sr, low 143Nd/144Nd, and radiogenic Pb isotope ratios,
suggesting that altered upper oceanic crust played an important role in the
magma source. The low δ98/95Mo values in the Central Mariana
Trough (–0.65‰ to –0.17‰) with mantle-like Sr-Nd-Pb but slightly low δ 7Li values provide direct evidence for the contribution of deep
recycled oceanic crust to the magma source of the back-arc basin lavas. The
isotopically light Mo magmas originated by partial melting of a residual
subducted slab (eclogite) after high degrees of dehydration and then
penetrated into the back-arc mantle. This interpretation provides a new
perspective with which to investigate the deep recycling of subducted
oceanic lithosphere and associated magma petrogenesis.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48754.1/600852/Across-arc-variations-in-Mo-isotopes-and

Tectonic controls on basement exhumation in the southern Rocky
Mountains (United States): The power of combined zircon (U-Th)/He and
K-feldspar 40Ar/39Ar thermochronology

Jason W. Ricketts; Jacoup Roiz; Karl E. Karlstrom; Matthew T. Heizler;
William R. Guenthner ...

Abstract:
The Great Unconformity of the Rocky Mountain region (western North
America), where Precambrian crystalline basement is nonconformably overlain
by Phanerozoic strata, represents the removal of as much as 1.5 b.y. of
rock record during 10-km-scale basement exhumation. We evaluate the timing
of exhumation of basement rocks at five locations by combining geologic
data with multiple thermochronometers. 40Ar/39Ar
K-feldspar multi-diffusion domain (MDD) modeling indicates regional
multi-stage basement cooling from 275 to 150 °C occurred at 1250–1100 Ma
and/or 1000–700 Ma. Zircon (U-Th)/He (ZHe) dates from the Rocky Mountains
range from 20 to 864 Ma, and independent forward modeling of ZHe data is
also most consistent with multi-stage cooling. ZHe inverse models at five
locations, combined with K-feldspar MDD and sample-specific geochronologic
and/or thermochronologic constraints, document multiple pulses of basement
cooling from 250 °C to surface temperatures with a major regional basement
exhumation event 1300–900 Ma, limited cooling in some samples during the
770–570 Ma breakup of Rodinia and/or the 717–635 Ma snowball Earth, and ca.
300 Ma Ancestral Rocky Mountains cooling. These data argue for a tectonic
control on basement exhumation leading up to formation of the
Precambrian-Cambrian Great Unconformity and document the formation of
composite erosional surfaces developed by faulting and differential uplift.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G49141.1/600853/Tectonic-controls-on-basement-exhumation-in-the

Reorienting the West African craton in Paleoproterozoic–Mesoproterozoic
supercontinent Nuna

Zheng Gong; David A.D. Evans; Nasrrddine Youbi; Abdelhak Ait Lahna; Ulf
Söderlund ...

Abstract:
The location of the West African craton (WAC) has been poorly constrained
in the Paleoproterozoic–Mesoproterozoic supercontinent Nuna (also known as
Columbia). Previous Nuna reconstruction models suggested that the WAC was
connected to Amazonia in a way similar to their relative position in
Gondwana. By an integrated paleomagnetic and geochronological study of the
Proterozoic mafic dikes in the Anti-Atlas Belt, Morocco, we provide two
reliable paleomagnetic poles to test this connection. Incorporating our new
poles with quality-filtered poles from the neighboring cratons of the WAC,
we propose an inverted WAC-Amazonia connection, with the northern WAC
attached to northeastern Amazonia, as well as a refined configuration of
Nuna. Global large igneous province records also conform to our new
reconstruction. The inverted WAC-Amazonia connection suggests a substantial
change in their relative orientation from Nuna to Gondwana, providing an
additional example of large-magnitude cumulative azimuthal rotations
between adjacent continental blocks over supercontinental cycles.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48855.1/600854/Reorienting-the-West-African-craton-in

New Ediacara-type fossils and late Ediacaran stratigraphy from the
northern Qaidam Basin (China): Paleogeographic implications

Ke Pang; Chengxi Wu; Yunpeng Sun; Qing Ouyang; Xunlai Yuan ...

Abstract:
Ediacara-type macrofossils characterize the late Ediacaran Period and are
pivotal in understanding the early evolution of animals on the eve of the
Cambrian explosion and useful in late Ediacaran biostratigraphy. They have
been discovered on almost all major paleocontinents, except the North China
and Tarim blocks, as well as on a series of northwestwest–oriented cratonic
fragments between the two blocks, including the Olongbuluke terrane of the
Qaidam block, where the terminal Ediacaran successions developed. We report
a newly discovered terminal Ediacaran biotic assemblage, the Quanjishan
assemblage, containing Ediacara-type fossils from the Zhoujieshan Formation
of the Quanji Group in the Olongbuluke terrane, Qaidam Basin, northwestern
China. The Quanjishan assemblage is dominated by the non-biomineralized
tubular taxon Shaanxilithes, which has the potential to be a
terminal Ediacaran index fossil, and by the iconic frondose rangeomorph Charnia, which represents the only unambiguous Ediacara-type
fossil discovered in northwestern China. The co-occurrence of Charnia and Shaanxilithes from the Quanjishan assemblage
likely constrains the depositional age of the Zhoujieshan Formation to be
terminal Ediacaran (ca. 550–539 Ma) and the immediately underlying
Hongtiegou diamictites to be late Ediacaran, probably representing
post-Gaskiers glacial deposition. The occurrence of post-Gaskiers Ediacaran
glaciation and similarities between the late Ediacaran–early Paleozoic
lithostratigraphic and biostratigraphic sequences in the Olongbuluke
terrane of the Qaidam block and the North China block suggest that these
two blocks may have been located close to each other during this time
period, and situated in the middle to high latitudes instead of the
equatorial region.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48842.1/600855/New-Ediacara-type-fossils-and-late-Ediacaran

Slab-derived sulfate generates oxidized basaltic magmas in the southern
Cascade arc (California, USA)

Michelle J. Muth; Paul J. Wallace

Abstract:
Whether and how subduction increases the oxidation state of Earth’s mantle
are two of the most important unresolved questions in solid Earth
geochemistry. Using data from the southern Cascade arc (California, USA),
we show quantitatively for the first time that increases in arc magma
oxidation state are fundamentally linked to mass transfer of isotopically
heavy sulfate from the subducted plate into the mantle wedge. We
investigate multiple hypotheses related to plate dehydration and melting
and the rise and reaction of slab melts with mantle peridotite in the
wedge, focusing on electron balance between redox-sensitive iron and sulfur
during these processes. These results show that unless slab-derived silicic
melts contain much higher dissolved sulfur than is indicated by currently
available experimental data, arc magma generation by mantle wedge melting
must involve multiple stages of mantle metasomatism by slab-derived
oxidized and sulfur-bearing hydrous components.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48759.1/600856/Slab-derived-sulfate-generates-oxidized-basaltic

Long-term Aptian marine osmium isotopic record of Ontong Java Nui
activity

Hironao Matsumoto; Rodolfo Coccioni; Fabrizio Frontalini; Kotaro Shirai;
Luigi Jovane ...

Abstract:
The early to mid-Aptian was punctuated by episodic phases of organic-carbon
burial in various oceanographic settings, which are possibly related to
massive volcanism associated with the emplacement of the Ontong Java,
Manihiki, and Hikurangi oceanic plateaus in the southwestern Pacific Ocean,
inferred to have formed a single plateau called Ontong Java Nui.
Sedimentary osmium (Os) isotopic compositions are one of the best proxies
for determining the timing of voluminous submarine volcanic episodes.
However, available Os isotopic records during the age are limited to a
narrow interval in the earliest Aptian, which is insufficient for the
reconstruction of long-term hydrothermal activity. We document the early to
mid-Aptian Os isotopic record using pelagic Tethyan sediments deposited in
the Poggio le Guaine (Umbria-Marche Basin, Italy) to precisely constrain
the timing of massive volcanic episodes and to assess their impact on the
marine environment. Our new Os isotopic data reveal three shifts to
unradiogenic values, two of which correspond to black shale horizons in the
lower to mid-Aptian, namely the Wezel (herein named) and Fallot Levels.
These Os isotopic excursions are ascribed to massive inputs of unradiogenic
Os to the ocean through hydrothermal activity. Combining the new Os
isotopic record with published data from the lowermost Aptian organic-rich
interval in the Gorgo a Cerbara section of the Umbria-Marche Basin, it can
be inferred that Ontong Java Nui volcanic eruptions persisted for ~5 m.y.
during the early to mid-Aptian.
View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48863.1/600857/Long-term-Aptian-marine-osmium-isotopic-record-of

Anisotropy-revealed change in hydration along the Alaska subduction
zone

Colton Lynner

Abstract:
Megathrust earthquake behavior in subduction zones is controlled by a
variety of factors including the hydration state of the subducting slab.
Increased hydration reduces the occurrence of great, damaging earthquakes
by diminishing the strength of the material along the interface between
tectonic plates. Understanding variations in hydration in subductions zones
is necessary for properly assessing the overall hazard posed by each
region. Fortunately, seismic anisotropy is strongly dependent upon
hydration of the subducting crust and lithosphere. I present shear-wave
splitting measurements that illuminate changes in anisotropy, and therefore
hydration, of the subducting Pacific plate beneath the Alaska subduction
zone (northern Pacific Ocean). Variations in shear-wave splitting directly
correlate to changes in the behavior of great, megathrust earthquakes. My
measurements show that the Shumagin seismic gap is characterized by a
hydrated subducting slab, explaining the long-term lack of great
earthquakes. Observations in the immediately adjacent Semidi segment, which
experiences great events regularly, indicate a far less hydrated slab.
These results are driven by the preferential alignment of paleo-spreading
fabrics of the Pacific plate. Where fabrics are more closely aligned with
the orientation of the trench, outer-rise faulting and plate hydration is
enhanced. These results highlight the importance of changes in preexisting
slab structures and subsequent hydration in the production of great,
damaging earthquakes.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48860.1/600696/Anisotropy-revealed-change-in-hydration-along-the

Out-of-phase Late Pleistocene glacial maxima in the Western Alps
reflect past changes in North Atlantic atmospheric circulation

Natacha Gribenski; Pierre G. Valla; Frank Preusser; Thibault Roattino;
Christian Crouzet ...

Abstract:
Paleoglacier reconstructions in the northern and southern forelands of the
European Alps indicate a synchronous Late Pleistocene glacial maximum
during Marine Isotope Stage (MIS) 2, in phase with global ice volume
records. However, strong controversy remains for the western foreland,
where scarce and indirect dating as well as modeling studies suggest
glacial maxima out of phase with the rest of the Alps. New luminescence
dating brings the first direct Late Pleistocene glacial chronology for the
western Alpine foreland and reveals two major glacier advances of similar
maximum extent, at ca. 75–60 and ca. 40–30 ka, coinciding with MIS 4 and
late MIS 3. We propose that asynchrony in glacial maxima between the
western and the northern and southern Alpine forelands results from a
progressive spatial reorganization of the atmospheric circulation over the
North Atlantic in response to Northern Hemisphere ice-sheet fluctuations.
While such a feedback mechanism has emerged from general circulation
models, our Late Pleistocene paleoglacial reconstruction permits tracking
of the spatiotemporal evolution of moisture advection patterns over Western
Europe.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48688.1/600697/Out-of-phase-Late-Pleistocene-glacial-maxima-in

Highly localized upper mantle deformation during plate boundary
initiation near the Alpine fault, New Zealand

Steven Kidder; David J. Prior; James M. Scott; Hamid Soleymani; Yilun Shao

Abstract:
Peridotite xenoliths entrained in magmas near the Alpine fault (New
Zealand) provide the first direct evidence of deformation associated with
the propagation of the Australian-Pacific plate boundary through the region
at ca. 25–20 Ma. Two of 11 sampled xenolith localities contain fine-grained
(40–150 mm) rocks, indicating that deformation in the upper mantle was
focused in highly sheared zones. To constrain the nature and conditions of
deformation, we combine a flow law with a model linking recrystallized
fraction to strain. Temperatures calculated from this new approach (625–970
°C) indicate that the observed deformation occurred at depths of 25–50 km.
Calculated shear strains were between 1 and 100, which, given known plate
offset rates (10–20 mm/yr) and an estimated interval during which
deformation likely occurred (<1.8 m.y.), translate to a total shear zone
width in the range 0.2–32 km. This narrow width and the position of
mylonite-bearing localities amid mylonite-free sites suggest that early
plate boundary deformation was distributed across at least ~60 km but
localized in multiple fault strands. Such upper mantle deformation is best
described by relatively rigid, plate-like domains separated by rapidly
formed, narrow mylonite zones.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48532.1/600699/Highly-localized-upper-mantle-deformation-during

Morphological selectivity of the Permian-Triassic ammonoid mass
extinction

Xu Dai; Dieter Korn; Haijun Song

Abstract:
Ammonoids suffered a diversity bottleneck during the Permian-Triassic mass
extinction (PTME) and experienced a rapid diversification in the Early
Triassic. However, the kinds of ammonoids that were more likely to survive
the PTME and that fueled subsequent diversification are still poorly known.
We compiled a comprehensive morphological data set and used the nonmetric
multidimensional scaling method to reveal the impact of the PTME on the
morphological selectivity of ammonoids. Our results show that
postextinction taxa occupied a quite different morphospace when compared
with the pre-extinction assemblages. The survivors were mainly smooth and
weakly ornamented forms, while the late Permian species were dominated by
coarsely ornamented forms. Contrary to previously recognized nonselective
patterns, these results suggest a morphological selectivity of the
Permian-Triassic crisis. Newcomers in the Griesbachian were mainly
compressed and smooth forms. This morphological shift from the coarsely
ornamented ammonoids dominating the Changhsingian to the smooth ammonoids
dominating the Griesbachian possibly suggests an ecological turnover of
ammonoids during the PTME.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48788.1/600700/Morphological-selectivity-of-the-Permian-Triassic

Permafrost thaw induced abrupt changes in hydrology and carbon cycling
in Lake Wudalianchi, northeastern China

Yuan Yao; Yongsong Huang; Jiaju Zhao; Li Wang; Youhua Ran ...

Abstract:
Lakes in the permafrost zone have been proposed to serve as key outlets for
methane and carbon dioxide emissions. However, there has been no geological
record of the hydrological and biogeochemical responses of lakes throughout
the thawing of surrounding permafrost. We use multiple biomarker and
isotopic proxies to reconstruct hydrological and biogeochemical changes in
Lake Wudalianchi in northeastern China during regional thawing of the
permafrost. We show permafrost thawing, as indicated by lignin degradation,
initiated rapid lake water freshening as a result of the opening of
groundwater conduits, and negative organic δ13C excursion due to
increased inorganic and organic carbon fluxes. These hydrological changes
were followed, with an ~5–7 yr delay, by abrupt and persistent increases in
microbial lake methanotrophy and methanogenesis, indicating enhanced
anaerobic organic decomposition and methane emissions from lakes as
permafrost thaws. Our data provide a detailed assessment of the processes
involved during permafrost thaw, and highlight the importance of lakes in
ventilating greenhouse gases to the atmosphere.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48891.1/600701/Permafrost-thaw-induced-abrupt-changes-in

Erosion of the Himalaya-Karakoram recorded by Indus Fan deposits since
the Oligocene

Han Feng; Huayu Lu; Barbara Carrapa; Hanzhi Zhang; Jun Chen ...

Abstract:
The Cenozoic erosion history of the Himalaya-Karakoram, which is a function
of tectonically driven uplift and monsoon climatic evolution in South Asia,
remains elusive, especially prior to the Miocene. Here, we present a
multiproxy geochemical and thermochronological analysis of the oldest
samples available from the Arabian Sea, which we used to investigate the
erosion history of the Himalayan and Karakoram orogenic system. The Indus
Fan records rapid and sustained erosion of the Himalayan-Karakoram
mountains from before 24 Ma (ca. 30) to ca. 16 Ma concurrent with changing
provenance from the Indian (Himalayan) and Eurasian plates. Our data,
combined with previous studies of younger Indus Fan deposits, indicate that
the mid-to-late Cenozoic erosion history of the Himalayan-Karakoram
mountains is overall consistent with a vigorous monsoonal climate from the
late Oligocene to middle Miocene and with changes in global climate in the
late Miocene, whereas erosion and deposition are relatively insensitive to
changes in sources and rock erodibility. Although tectonic processes were
active throughout, we suggest that the erosional signatures of the
Himalayan-Karakoram mountains from the Indus Fan largely preserve a record
of climate changes since the Oligocene.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48445.1/600703/Erosion-of-the-Himalaya-Karakoram-recorded-by

Raising the West: Mid-Cenozoic Colorado-plano related to subvolcanic
batholith assembly in the Southern Rocky Mountains (USA)?

Peter W. Lipman

Abstract:
The Southern Rocky Mountains of Colorado, United States, have the highest
regional elevation in North America, but present-day crustal thickness
(~42–47 km) is no greater than for the adjacent, topographically lower High
Plains and Colorado Plateau. The chemistry of continental-arc rocks of the
mid-Cenozoic Southern Rocky Mountain volcanic field, calibrated to
compositions and Moho depths at young arcs, suggests that paleocrustal
thickness may have been 20%–35% greater than at present and elevations
accordingly higher. Thick mid-Cenozoic Rocky Mountain crust and high
paleo-elevations, comparable to those inferred for the Nevadaplano farther
west in the United States from analogous volcanic chemistry, could be
consistent with otherwise-perplexing evidence for widespread rapid erosion
during volcanism. Variable mid-Cenozoic crustal thickening and uplift could
have resulted from composite batholith growth during volcanism,
superimposed on prior crustal thickening during early Cenozoic (Laramide)
compression. Alternatively, the arc–crustal thickness calibration may be
inappropriate for high-potassium continental arcs, in which case other
published interpretations using similar methods may also be unreliable.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48963.1/600704/Raising-the-West-Mid-Cenozoic-Colorado-plano

Labyrinth patterns in Magadi (Kenya) cherts: Evidence for early
formation from siliceous gels

Kennie Leet; Tim K. Lowenstein; Robin W. Renaut; R. Bernhart Owen; Andrew
Cohen

Abstract:
Sedimentary cherts, with well-preserved microfossils, are known from the
Archean to the present, yet their origins remain poorly understood. Lake
Magadi, Kenya, has been used as a modern analog system for understanding
the origins of nonbiogenic chert. We present evidence for synsedimentary
formation of Magadi cherts directly from siliceous gels. Petrographic
thin-section analysis and field-emission scanning electron microscopy of
cherts from cores drilled in Lake Magadi during the Hominin Sites and
Paleolakes Drilling Project in 2014 led to the discovery of two-dimensional
branching "labyrinth patterns" in chert, which are a type of fractal
"squeeze" pattern formed at air-liquid interfaces. Labyrinth patterns
preserved in chert from Lake Magadi cores indicate invasion of air along
planes in dewatering gels. These patterns support the precipitation of
silica gels in the saline-alkaline Lake Magadi system and syndepositional
drying of gels in contact with air as part of chert formation. Recognizing
cherts as syndepositional has been critical for our use of them for U-Th
dating. Identification of labyrinth patterns in ancient cherts can provide
a better understanding of paleoenvironmental and geochemical conditions in
the past.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48771.1/600705/Labyrinth-patterns-in-Magadi-Kenya-cherts-Evidence

Serpentinized peridotite versus thick mafic crust at the Romanche
oceanic transform fault

Emma P.M. Gregory; Satish C. Singh; Milena Marjanović; Zhikai Wang

Abstract:
The crust beneath transform faults at slow-spreading ridges has been
considered to be thin, comprising a thin mafic layer overlying
serpentinized peridotite. Using wide-angle seismic data, we report the
presence of a Moho at ~6 km depth and a low-velocity anomaly extending down
to 9 km beneath the 20-km-wide Romanche transform valley floor in the
equatorial Atlantic Ocean. The low crustal velocities above the Moho could
be due to either highly serpentinized mantle peridotite or fractured mafic
rocks. The existence of clear Moho reflections and the occurrence of a
large crustal-depth rupture during the 2016 magnitude 7.1 earthquake
suggest that the crust likely consists of fractured mafic material.
Furthermore, the presence of low velocities below the Moho advocates for
extensive serpentinization of the mantle, indicating that the Moho
reflection is unlikely to be produced by a serpentinization front. The
crust to the north of the transform fault likely consists of mafic
material, but that in the south appears to be more amagmatic, possibly
containing serpentinized peridotite. Our results imply that the transform
fault structure is complex and highly heterogeneous, and thus would have
significant influence on earthquake rupture and alteration processes.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G49097.1/600706/Serpentinized-peridotite-versus-thick-mafic-crust

Keep your checklists handy because the 62nd Supplement to the American Ornithological Society’s Check-list of North American Birds, publishing today in Ornithology, includes numerous updates to the classification of the continent’s bird species. A few highlights from this year’s supplement, detailed below, include species splits for Mew Gull, Barred Owl, and Sedge Wren, among quite a few others; a transfer back to an old genus for Ruby-crowned Kinglet; and a revision of the linear sequence of passerine families. The Check-list, published since 1886, is updated annually by the AOS’s North American Classification Committee (NACC), the official authority on the names and classification of the region’s birds, and is consulted by birders and professional ornithologists alike. 

The full Check-list supplement is available at: https://academic.oup.com/auk/advance-article/doi/10.1093/ornithology/ukab037/6309332.

Species Splits

Splitting of Barred Owl and Cinereous Owl (Proposal 2021-C-8)

Based primarily on differences in vocalizations, the Barred Owl (Strix varia) is being split into two species, the Barred Owl, which retains its English and scientific names for U.S. and Canadian populations, and the Cinereous Owl (Strix sartorii) for its counterpart in Mexico. “Vocalizations are particularly important for species recognition in owls,” NACC chair Terry Chesser of the U.S. Geological Survey explains. The proposal to split Barred Owl into two species, submitted by Nathan Pieplow (University of Colorado Boulder) and Andrew Spencer (Cornell Laboratory of Ornithology), focused on key differences in both their rhythm and series songs, specifically in the series song, which they summarize as: “[sartorii’s] syncopated beginning, its uniformity in pitch, and its lack of a drawn-out ‘hoo-wah’ note at the end. In the Barred Owl’s series song, the highest and loudest notes are at the end, while in that of sartorii, the highest and loudest notes are in the middle.” 

Pieplow and colleagues were surprised and dismayed, when returning to many previously known locations to record vocalizations of Cinereous Owl, that there appears to have been a severe decline and reduction in range for this species. Moreover, while searching at sites in Oaxaca, Mexico, where this species had previously been found, they instead observed the Fulvous Owl (Strix fulvescens), a close relative more typically found farther south in Mexico and Central America, but which appears to have extended its range northward.

Splitting of Mew Gull into Common Gull and Short-billed Gull (Proposal 2021-A-3)

“If you’re a coast-to-coast birder, you may be able to pick up a new species this winter,” Chesser quips, describing the split of Mew Gull (Larus canus) into two species: Common Gull (Larus canus) and Short-billed Gull (Larus brachyrhynchus), the name used for this species as long ago as the first edition of the Check-list in 1886. The Common Gull breeds in Eurasia and is a casual visitor to the eastern U.S. and Canada, and occasionally ventures to Alaska, whereas the Short-billed Gull breeds in northwestern North America and winters south along the Pacific coast and also into the interior, primarily of the western U.S. This split is based mainly on differences in display vocalizations but also on genetic and other morphological differences outlined in a proposal by NACC member Pamela C. Rasmussen (Michigan State University). These species had been lumped based on what is now viewed as weak evidence from a paper published in 1919. 

Splitting of Sedge Wren and Grass Wren (Proposal 2021-C-3)

Previous ideas about how Sedge Wren (Cistothorus platensis) should be divided turn out to be misguided, according to Chesser, who authored a proposal, based in part on a prior proposal to South American Classification Committee (SACC), to split this species. In the 1998 Check-list, Sedge Wren was considered a single species distributed from Canada to extreme southern South America, comprising three distinct groups: stellaris, whose range extended from Canada to Panama, and two other groups distributed in South America, platensis and polyglottus. However, the species split, which is based on vocalizations and genetics, does not occur where we might have expected it would, based on what we thought we knew about intraspecific variation in the species. Instead, it turns out that the populations breeding in Canada and the U.S. are distinct from all other populations, including those breeding in Mexico, Central America, and South America, and are being split from the rest. The new southern species, Grass Wren (Cistothorus platensis), will retain the scientific name due to reasons of priority, but the new northern species will keep the English name Sedge Wren (Cistothorus stellaris). The SACC had previously made this split after consideration of the separate proposal to that committee.

Transfers Between Genera

A New (Old) Genus for the Ruby-crowned Kinglet (Proposal 2021-A-9)

The Ruby-crowned Kinglet (Regulus calendula, now Corthylio calendula), a tiny olive-colored songbird with a bright red but hard-to-see crown in males, breeds in forests across the U.S. and Canada and winters as far south as Central America. It’s one of six species in the family Regulidae, all currently placed in the same genus, Regulus. Two species are found in the New World, Golden-crowned Kinglet (Regulus satrapa) and Ruby-crowned Kinglet; and four species in the Old World, including the Firecrest (Regulus ignicapilla) and Goldcrest (Regulus regulus). In the 1931 AOU Check-list, the Ruby-crowned Kinglet had been transferred to its own genus, Corthylio, based on morphological differences from the other species, but as of the 1957 Check-list it was returned to Regulus, with Corthylio relegated to subgenus status, and it has been placed in Regulus ever since. 

“It has long been known that the Ruby-crowned Kinglet is markedly divergent from the other regulids in plumage and other aspects of external anatomy, reflected by the fact that the genus Corthylio Cabanis, 1853, was erected for this species,” authors Brandon Woo and Natalia C. García (Cornell University) and NACC member Pamela C. Rasmussen (Michigan State University) state in their proposal. Moreover, vocal and genetic data, including molecular studies dating from the early days of molecular systematics to the current genomics era, have consistently shown that the Ruby-crowned Kinglet is strikingly different from other species placed in Regulus. 

“This is my favorite proposal of the year,” Chesser notes, “and I think it will be interesting to birders for the same reasons. I hope this generates new appreciation for an unassuming little bird that is of great interest evolutionarily and really distinctive from other species in its family.”

Linear Sequence Revision

Revision of Linear Sequence of Passerine Families (Proposal 2021-B-7)

A proposal by Chesser and NACC member Shawn Billerman based on new, concordant information from three recent genomic studies of passerines has led to a reshuffling and update to the linear sequence of passerine families to better reflect their phylogenetic relationships. “This is a big step forward that reflects a wealth of new information on evolutionary relationships among passerine families,” Chesser explains. “This revision will create short-term disturbance, but we think this will be more than offset by the benefits of having a more scientifically accurate classification, which should be stable into the future, with occasional minor changes. The fact that several genomic studies produced virtually the same phylogeny was the key factor in convincing us that the time was right for this revision.”

About the Journal

Ornithology (formerly, The Auk: Ornithological Advances) is a peer-reviewed, international journal of ornithology published by the American Ornithological Society. The journal’s name changed to Ornithology in January of 2021. Ornithology commenced publication in 1884 and in 2009 was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

This year marks the 100th anniversary of the discovery of insulin, a scientific breakthrough that transformed Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, from a terminal disease into a manageable condition.

Today, Type 2 diabetes is 24 times more prevalent than Type 1. The rise in rates of obesity and incidence of Type 2 diabetes are related and require new approaches, according to University of Arizona researchers, who believe the liver may hold the key to innovative new treatments.

"All current therapeutics for Type 2 diabetes primarily aim to decrease blood glucose. So, they are treating a symptom, much like treating the flu by decreasing the fever," said Benjamin Renquist, an associate professor in the UArizona College of Agriculture and Life Sciences and BIO5 Institute member. "We need another breakthrough."

In two newly published papers in Cell Reports, Renquist, along with researchers from Washington University in St. Louis, the University of Pennsylvania and Northwestern University, outline a new target for Type 2 diabetes treatment.

Renquist, whose research lab aims to address obesity-related diseases, has spent the last nine years working to better understand the correlation between obesity, fatty liver disease and diabetes, particularly how the liver affects insulin sensitivity.

"Obesity is known to be a cause of Type 2 diabetes and, for a long time, we have known that the amount of fat in the liver increases with obesity," Renquist said. "As fat increases in the liver, the incidence of diabetes increases."

This suggested that fat in the liver might be causing Type 2 Diabetes, but how fat in the liver could cause the body to become resistant to insulin or cause the pancreas to over-secrete insulin remained a mystery, Renquist said.

Renquist and his collaborators focused on fatty liver, measuring neurotransmitters released from the liver in animal models of obesity, to better understand how the liver communicates with the brain to influence metabolic changes seen in obesity and diabetes.

"We found that fat in the liver increased the release of the inhibitory neurotransmitter Gamma-aminobutyric acid, or GABA," Renquist said. "We then identified the pathway by which GABA synthesis was occurring and the key enzyme that is responsible for liver GABA production - GABA transaminase."

A naturally occurring amino acid, GABA is the primary inhibitory neurotransmitter in the central nervous system, meaning it decreases nerve activity.

Nerves provide a conduit by which the brain and the rest of the body communicate. That communication is not only from the brain to other tissues, but also from tissues back to the brain, Renquist explained.

"When the liver produces GABA, it decreases activity of those nerves that run from the liver to the brain. Thus, fatty liver, by producing GABA, is decreasing firing activity to the brain," Renquist said. "That decrease in firing is sensed by the central nervous system, which changes outgoing signals that affect glucose homeostasis."

To determine if increased liver GABA synthesis was causing insulin resistance, graduate students in Renquist's lab, Caroline Geisler and Susma Ghimire, pharmacologically inhibited liver GABA transaminase in animal models of Type 2 diabetes.

"Inhibition of excess liver GABA production restored insulin sensitivity within days," said Geisler, now a postdoctoral researcher at the University of Pennsylvania and lead author on the papers. "Longer term inhibition of GABA-transaminase resulted in decreased food intake and weight loss."

Researchers wanted to ensure the findings would translate to humans. Kendra Miller, a research technician in Renquist's lab, identified variations in the genome near GABA transaminase that were associated with Type 2 diabetes. Collaborating with investigators at Washington University, the researchers showed that in people with insulin resistance, the liver more highly expressed genes involved in GABA production and release.

The findings are the foundation of an Arizona Biomedical Research Commission-funded clinical trial currently underway at Washington University School of Medicine in St. Louis with collaborator Samuel Klein, co-author on the study and a Washington University professor of medicine and nutritional science. The trial will investigate the use of a commercially available Food and Drug Administration-approved inhibitor of GABA transaminase to improve insulin sensitivity in people who are obese.

"A novel pharmacological target is just the first step in application; we are years away from anything reaching the neighborhood pharmacy," Renquist said. "The magnitude of the obesity crisis makes these promising findings an important first step that we hope will eventually impact the health of our family, friends and community."

Arlington, Va., June 29, 2021 - In the midst of the COVID-19 pandemic, infection preventionists at two Southern California hospitals took extreme measures to stop the spread of a deadly fungus that has emerged in the U.S. and around the world. The two will detail their proactive responses in oral presentations today at the Association for Professionals in Infection Control and Epidemiology's (APIC's), 48th Annual Conference.

In separate responses, Scripps Memorial in La Jolla and UCLA Health in Los Angeles isolated suspected or confirmed patients, worked closely with public health departments and information technology and lab teams at their facilities, and implemented aggressive measures to prevent the pathogen, Candida auris, from spreading.

"The fact that these two teams recognized this threat and were able to mobilize so quickly and effectively while also on high alert for COVID is remarkable," said APIC 2021 President Ann Marie Pettis, BSN, RN, CIC, FAPIC. "Their case studies demonstrate how important it is that hospitals, clinics, and long-term care facilities have enough infection preventionists and resources to train staff and monitor safety protocols so they can prevent harm on multiple fronts."

C. auris is a type of fungus that causes severe, often fatal infections and is resistant to most antifungal drugs. It can be carried on a patient's skin and can survive on surfaces for more than a month, allowing it to spread easily among patients. Most hospital disinfectants can't kill C. auris, making it difficult to eradicate from the healthcare environment. It is also easy to misidentify in lab tests.

In March 2020, during the initial influx of COVID-19 patients, infection preventionist Elizabeth A. Jefferson, BS, PhD, CIC, of Scripps Memorial, was notified that her facility had received the first known case of C. auris in San Diego County.

Initially flagged and isolated because the patient had received healthcare abroad, laboratory tests confirmed C. auris in a wound. The patient remained hospitalized in isolation for 47 days, during which time the team implemented aggressive cleaning measures, including use of a disinfectant that was effective against C. auris and UV light for terminal cleaning of all patient rooms.

"Education of staff was essential," said Jefferson. "Staff had to clean and disinfect the room twice a day, and then clean any shared equipment, because if Candida auris sets up shop in your facility, it is extremely difficult to get rid of."

The team partnered with public health, including the CDC's Antibiotic Resistance Lab Network, on routine surveillance testing to ensure there was no transmission.

"Hospitals need to be on the lookout for C. auris," said Jefferson. "You don't know if a patient is colonized or infected unless you have specialized laboratory equipment."

As a result, there was no transmission of the fungal pathogen that has infected nearly 1,800 patients in 15 states and the District of Columbia since it was first detected in the U.S. in 2015.

When C. auris started to surge in Southern California during the summer of 2020, UCLA Health was ready. Knowing the devastation C. auris had caused in other states, they had already created a multi-level notification system designed to catch potential cases early and prevent transmission.

Collaborating with their electronic medical records (EMR) team and the lab, the infection preventionists made sure the EMR system was set up to screen every patient for both COVID and Candida auris when they entered the facility. High-risk patients were flagged and tested appropriately with subsequent notifications sent to infection prevention, environmental services, the lab, and nursing. The system placed holds in patient charts prior to discharge or transfer to enable communication with the health department and receiving facilities about the patient's C. auris status.

The system triggered reminders for stringent cleaning protocols which included testing of environmental surfaces after terminal cleaning to ensure that the patient's room was clear of the organism.

"Having an in-house lab that could test for C. auris and collaborating with the EMR team to build a set of screening steps into our EMR created a failsafe way to ensure we could monitor and track any suspected C. auris cases at our facility. This process was effective in prevention of cross contamination in the healthcare environment" said Urvashi Parti, MPH, infection preventionist at UCLA Health.

Another factor for success was engaging senior leadership so they understood the importance of monitoring both C. auris and COVID at the same time.

"We had the full support of senior leaders who made sure we had the resources to support early identification of C. auris during the COVID-19 pandemic," said Shaunte Walton, MS, CIC, Health System Director of Clinical Epidemiology & Infection Prevention at UCLA Health.

Black men most likely to benefit from advanced prostate cancer therapies are 11 percent less likely to get them than non-Black men. This happens despite apparent equal opportunities in obtaining health care services, a new study in American veterans shows.

Publishing in the journal Cancer online June 29, the study showed that Black male veterans were slightly (5 percent) more likely to receive radiation or surgery for prostate cancer than non-Black men and that veterans of all races likely to benefit from such definitive therapy were also 40 percent more likely to get it compared to those who did not need it.

Led by researchers from NYU Langone Health and Perlmutter Cancer Center, the new analysis showed that, despite these broad advantages in obtaining advanced care, the Black men most likely to benefit from these treatments (i.e., those men with aggressive prostate cancer who were otherwise healthy) were 11 percent less likely to get them than non-Black men of similar age and cancer severity. And other research has documented that Black men are still three times more likely to die from the disease than non-Black patients.

"Our study suggests, for reasons that remain unclear, that Black men who need treatment may be choosing against the most beneficial prostate cancer therapies (which are often more invasive), or that such 'high- benefit' treatments, are not being offered to them as aggressively as they are to non-Black patients," says study co-investigator Joseph Ravenell, MD, associate dean for diversity affairs and inclusion at NYU Langone.

Ravenell, an associate professor at NYU Grossman School of Medicine and co-leader of community outreach and engagement at Perlmutter Cancer Center, says one possible reason for this treatment disparity is that, as past studies have found, some Black men may have greater fears than non-Black patients about side effects of aggressive therapy, such as the risk of incontinence and erectile dysfunction. These fears, he says, and other underlying reasons related to their expectations of treatment should be discussed directly with Black patients when treatment options are being considered.

"Our findings strongly indicate that patients and physicians should discuss fears, values, and preferences when considering all of the relevant treatment options for prostate cancer," says study senior investigator and urologic surgeon Danil Makarov, MD, MHS.

"Despite great strides in prostate cancer care over the past few decades, racial disparities in care persist, and there remains a lot to be done to better understand why this is happening and what we can do to finally close the gap," says Makarov, an associate professor in the Departments of Urology and Population Health at NYU Grossman School of Medicine.

"At the end of day, our goal is to offer patients the most appropriate cancer care they need, using a culturally sensitive approach," says Makarov, also a member of the Perlmutter Cancer Center, whose team is examining interventions such as counseling Black men on their risks and the benefits of prostate cancer screening, which could reduce disparities in care.

The findings come from an analysis of the medical records of 35,427 men treated for early to moderate prostate cancer at U.S. Veterans' Health Administration facilities from 2011 to 2017. Most were over age 60, were married, and had no other serious health issue.

The study also confirmed earlier work that Black men are likely to be diagnosed with prostate cancer two years earlier than men of other races across all age groups. Black men are also more likely to be diagnosed with more aggressive forms of the disease than their non-Black counterparts. Makarov says more research is needed to determine if any underlying structural or cultural bias is behind this disparity.

For the study, researchers analyzed data from the Veterans Health Administration's (VHA) Corporate Data Warehouse and Medicare. From these national databases, they identified all men diagnosed with prostate cancer and characterized them by their life expectancy (based on their other medical diagnoses) and the severity of their prostate cancer. Men in their 50s with aggressive cancer, for example, who had surgery or radiation were deemed to have received "high-benefit" treatment because it had the greatest impact on their life expectancy. By contrast, much older men with non-aggressive cancers would have been assessed as "low" benefit for aggressive prostate cancer treatments because these treatments would have had little impact on how long they lived.

Researchers focused on VHA data because it's the nation's largest provider of cancer care.

Prostate cancer remains the second-leading cause of cancer death among American men, with more than 34,000 dying annually from the disease. The U.S. National Cancer Institute estimates that 248,000 men will be diagnosed with prostate cancer in 2021, most in its earliest stages.

Scientists have for the first time detected black holes eating neutron stars, "like Pac Man", in a discovery documenting the collision of the two most extreme and enigmatic objects in the Universe.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US and the Virgo gravitational-wave observatory in Italy have captured the gravitational waves from the death spiral and merger of a neutron star with a black hole, not once but twice. The findings are published today.

The researchers say their observations will help unlock some of the most complex mysteries of the Universe, including the building blocks of matter and the workings of space and time.

More than 1,000 scientists were involved with the world-first detections, with many from Australia, including The Australian National University, leading the way.

Distinguished Professor Susan Scott, a co-author on the study based at the ANU Research School of Physics in the Centre for Gravitational Astrophysics, said the events occurred about a billion years ago but were so massive that we are still able to observe their gravitational waves today.

"These collisions have shaken the Universe to its core and we've detected the ripples they have sent hurtling through the cosmos," she said.

"Each collision isn't just the coming together of two massive and dense objects. It's really like Pac-Man, with a black hole swallowing its companion neutron star whole.

"These are remarkable events and we have waited a very long time to witness them. So it's incredible to finally capture them."

One event included a black hole with a mass nine times bigger than our own sun and a neutron star with two times our sun's mass. The other event included a black hole with about six times the mass of our sun and a neutron star with 1.5 times its mass.

Professor Scott, also a Chief Investigator at the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), said the international team had previously captured many events involving two black holes colliding as well as two neutron stars smashing together.

"Now, we've completed the last piece of the puzzle with the first confirmed observations of gravitational waves from a black hole and a neutron star colliding," she said.

Dr Johannes Eichholz, from the ANU Centre for Gravitational Astrophysics and an Associate Investigator with OzGrav, said the two detections were originally made on 5 and 15 January 2020.

"These kind of detections are incredibly rare," he said.

"We haven't detected these events once - but twice and within 10 days of each other.

"Like the ripples from these two events, which have been felt a billion years later, these findings will have a profound impact on our understanding of the Universe for many years to come."