Culture

What is the cost of 1 ton of a greenhouse gas? When a climate-warming gas such as carbon dioxide or methane is emitted into the atmosphere, its impacts may be felt years and even decades into the future - in the form of rising sea levels, changes in agricultural productivity, or more extreme weather events, such as droughts, floods, and heat waves. Those impacts are quantified in a metric called the "social cost of carbon," considered a vital tool for making sound and efficient climate policies.

Now a new study by a team including researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley reports that the social cost of methane - a greenhouse gas that is 30 times as potent as carbon dioxide in its ability to trap heat - varies by as much as an order of magnitude between industrialized and developing regions of the world.

Published recently in the journal Nature, the study finds that by accounting for economic inequalities between countries and regions, the social cost of methane drops by almost a factor of 10 in sub-Saharan Africa and jumps by almost a factor of 10 for industrialized countries, such as the United States. The study calculated a global mean estimate of the social cost of methane of $922 per metric ton (not accounting for the inequity), decreasing to $130 per metric ton for sub-Saharan Africa and rising to $8,040 per metric ton for the U.S.

"The paper broadly supports the previous U.S. government estimates of the social cost of methane, but if you use the number the way it's typically used - as a global estimate, as if all countries are equal - then it doesn't account for the inequities," said Berkeley Lab scientist William Collins, one of the study's co-authors.

The lead authors of the study were David Anthoff, a professor in UC Berkeley's Energy and Resources Group, and Frank Errickson, a graduate student in the group at the time of the study. "The Biden administration's climate policy agenda calls for prioritizing environmental justice and equity. We provide a way for them to directly incorporate concerns for equity in methane emission regulations," said Errickson, now a postdoctoral fellow at Princeton University. "Our results capture that the same climate impact, when measured in dollars, causes a greater loss in well-being for low-income regions relative to wealthy ones."

Like the social cost of carbon, the social cost of methane is a metric that is not widely used by the public but is increasingly used by government agencies and corporations in making decisions around policies and capital investments. By properly accounting for future damages that may be caused by greenhouse gas emissions, policymakers can weigh present costs against future avoided harms. In fact, the recent White House executive order on the climate crisis established a working group to provide an accurate accounting of the social costs of carbon, methane, and nitrous oxide within a year.

"President Biden's action represents a much-needed return of science-based policy in the United States," said Anthoff. "Devastating weather events and wildfires have become more common, and the costs of climate impacts are mounting."

"The social costs of methane and carbon dioxide are used directly in cost-benefit analyses all the time," Collins said. "You have to figure out how to maximize the benefit from a dollar spent on mitigating methane emissions, as opposed to any of the other ways in which one might choose to spend that dollar. You want to make sure that you are not using a gold-plated band-aid."

Given the current estimate of global methane emissions of 300 million metric tons per year, that puts the annual social cost of methane at nearly $300 billion, said Collins, the head of Berkeley Lab's Climate and Ecosystem Sciences Division and also a professor in UC Berkeley's Earth and Planetary Science Department. "Wet areas will get wetter and dry areas dryer, so there's an increase in severity of storms and droughts," he said. "The cost would include all the things that flow from that, such as infrastructure damaged, increased expenditures around keeping places cool, health risks associated with heat, and so on."

While some methane comes from natural sources - mostly wetlands - about 60% of methane emissions come from human activity, including agriculture, fossil fuel production, landfills, and livestock production. It is considered a short-lived climate pollutant, staying in the atmosphere for only a decade or so, compared to more than 100 years for carbon dioxide.

"Given its potency as a greenhouse gas, regulating emissions of methane has long been recognized as critical component for designing an economically efficient climate policy," said Anthoff. "Our study updates the social cost of methane estimates and fills a critical gap in determining social costs."

Under the Obama administration, the price was estimated at about $1,400 per metric ton. The Berkeley researchers made a technical correction in accounting for offsetting influences on the climate system, arriving at global mean estimate of $922 per metric ton. "We're suggesting they slightly overestimated it," Collins said.

But more importantly, the uncertainty around the social cost of methane comes more from the social side, not the physics. "As a climate scientist, we've been busy trying to improve our estimates of the warming caused by methane," Collins said. "But it turns out the physics side is no longer the major source of uncertainty in the social cost of methane. It's now moved to the socio-economic sector, accounting for the damages and inequities."

How societies choose to develop in the future - such as expanding cities along coastlines or areas prone to flooding or wildfires, or moving away from such areas - are a big unknown. "If we choose mitigate climate change more aggressively, the social cost of methane drops drastically," Collins said.

"Continuing our work to further explore the relationship between climate change and socioeconomic uncertainties - not to mention the complex but important issues that arise when we account for equity - is a promising area for future research and policy exploration," said Anthoff.

Astronomers using data from NASA and the ESA (European Space Agency) telescopes have released a new all-sky map of the outermost region of our galaxy. Known as the galactic halo, this area lies outside the swirling spiral arms that form the Milky Way's recognizable central disk and is sparsely populated with stars. Though the halo may appear mostly empty, it is also predicted to contain a massive reservoir of dark matter, a mysterious and invisible substance thought to make up the bulk of all the mass in the universe.

The data for the new map comes from ESA's Gaia mission and NASA's Near Earth Object Wide Field Infrared Survey Explorer, or NEOWISE, which operated from 2009 to 2013 under the moniker WISE. The study, led by astronomers at the Center for Astrophysics | Harvard & Smithsonian and published today in Nature, makes use of data collected by the spacecraft between 2009 and 2018.

The new map reveals how a small galaxy called the Large Magellanic Cloud (LMC) - so-named because it is the larger of two dwarf galaxies orbiting the Milky Way - has sailed through the Milky Way's galactic halo like a ship through water, its gravity creating a wake in the stars behind it. The LMC is located about 160,000 light-years from Earth, and is less than one quarter the mass of the Milky Way. Though the inner portions of the halo have been mapped with a high level of accuracy, this is the first map to provide a similar picture of the halo's outer regions, where the wake is found - about 200,000 light years to 325,000 light years from the galactic center. Previous studies have hinted at the wake's existence, but the all-sky map confirms its presence and offers a detailed view of its shape, size, and location.

This disturbance in the halo also provides astronomers with an opportunity to study something they can't observe directly: dark matter. Though it doesn't emit, reflect, or absorb light, the gravitational influence of dark matter has been observed across the universe. It is thought to create a scaffolding on which galaxies are built, such that without it, galaxies would fly apart as they spin. Dark matter is estimated to be five times more common in the universe than all the matter that emits or interacts with light, from stars to planets to gas clouds.

While there are multiple theories about the nature of dark matter, all of them indicate that it should be present in the Milky Way's halo. If that's the case, then as the LMC sails through this region, it should leave a wake in the dark matter as well. The wake observed in the new star map is thought to be the outline of this dark matter wake; the stars are like leaves on the surface of this invisible ocean, their position shifting with the dark matter.

The interaction between the dark matter and the Large Magellanic Cloud has big implications for our galaxy. As the LMC orbits the Milky Way, the dark matter's gravity drags on the LMC and slows it down. This will cause the dwarf galaxy's orbit to get smaller and smaller, until the galaxy finally collides with the Milky Way in about 2 billion years. These types of mergers might be a key driver in the growth of massive galaxies across the universe. In fact, astronomers think the Milky Way merged with another small galaxy about 10 billion years ago.

"This robbing of a smaller galaxy's energy is not only why the LMC is merging with the Milky Way but also why all galaxy mergers happen," said Rohan Naidu, a graduate student in astronomy at Harvard University and a co-author of the new paper. "The wake in our map is a really neat confirmation that our basic picture for how galaxies merge is on point!"

A Rare Opportunity

The authors of the paper also think the new map - along with additional data and theoretical analyses - may provide a test for different theories about the nature of dark matter, such as whether it consists of particles, like regular matter, and what the properties of those particles are.

"You can imagine that the wake behind a boat will be different if the boat is sailing through water or through honey," said study co-author Charlie Conroy, a professor at Harvard University and astronomer at the Center for Astrophysics. "In this case, the properties of the wake are determined by which dark matter theory we apply."

Conroy led the team that mapped the positions of over 1,300 stars in the halo. The challenge arose in trying to measure the exact distance from Earth to a large portion of those stars: It's often impossible to figure out if a star is faint and close by or bright and far away. The team used data from ESA's Gaia mission, which provides the location of many stars in the sky but cannot measure distances to the stars in the Milky Way's outer regions.

After identifying stars most likely located in the halo (because they were not obviously inside our galaxy or in the LMC), the team looked for stars that belong to a class of giant stars that have a specific light "signature" detectable by NEOWISE. Knowing the basic properties of the selected stars enabled the team to figure out their distance from Earth and create the new map. It charts a region starting about 200,000 light-years from the Milky Way's center, or about where the LMC's wake was predicted to begin, and extends about 125,000 light-years beyond that.

Conroy and his colleagues were inspired to hunt for LMC's wake after learning about a team of astrophysicists at the University of Arizona in Tucson who make computer models predicting what dark matter in the galactic halo should look like. The two groups worked together on the new study. One of the models by the Arizona team, which is in the new study, predicted the general structure and specific location of the star wake revealed in the new map. Once the data had confirmed that the model was correct, the team was able to confirm what other investigations have also hinted at: that the LMC is likely on its first orbit around the Milky Way. If the smaller galaxy had already made multiple orbits, the shape and location of the wake would be significantly different from what has been observed. Astronomers think the LMC formed in the same environment as the Milky Way and another nearby galaxy, M31, and was on a very long first orbit around our galaxy (about 13 billion years). Its next orbit will be much shorter due to its interaction with the Milky Way.

"Confirming our theoretical prediction with observational data tells us that our understanding of the interaction between these two galaxies, including the dark matter, is on the right track," said University of Arizona doctoral student in astronomy Nicolás Garavito-Camargo, who led work on the model used in the paper.

The new map also provides astronomers with a rare opportunity to test the properties of the dark matter (the notional water or honey) in our own galaxy. In the new study, Garavito-Camargo and colleagues used a popular dark matter theory called cold dark matter that fits the observed star map relatively well. Now the University of Arizona team is running simulations that use different dark matter theories, to see which one best matches the wake observed in the stars.

"It's a really special set of circumstances that came together to create this scenario that lets us test our dark matter theories," said Gurtina Besla, a co-author of the study and an associate professor at the University of Arizona. "But we can only realize that test with the combination of this new map and the dark matter simulations that we built."

In the field of robotics, researchers are continually looking for the fastest, strongest, most efficient and lowest-cost ways to actuate, or enable, robots to make the movements needed to carry out their intended functions.

The quest for new and better actuation technologies and 'soft' robotics is often based on principles of biomimetics, in which machine components are designed to mimic the movement of human muscles--and ideally, to outperform them. Despite the performance of actuators like electric motors and hydraulic pistons, their rigid form limits how they can be deployed. As robots transition to more biological forms and as people ask for more biomimetic prostheses, actuators need to evolve.

Associate professor (and alum) Michael Shafer and professor Heidi Feigenbaum of Northern Arizona University's Department of Mechanical Engineering, along with graduate student researcher Diego Higueras-Ruiz, published a paper in Science Robotics presenting a new, high-performance artificial muscle technology they developed in NAU's Dynamic Active Systems Laboratory. The paper, titled "Cavatappi artificial muscles from drawing, twisting, and coiling polymer tubes," details how the new technology enables more human-like motion due to its flexibility and adaptability, but outperforms human skeletal muscle in several metrics.

"We call these new linear actuators cavatappi artificial muscles based on their resemblance to the Italian pasta," Shafer said.

Because of their coiled, or helical, structure, the actuators can generate more power, making them an ideal technology for bioengineering and robotics applications. In the team's initial work, they demonstrated that cavatappi artificial muscles exhibit specific work and power metrics ten and five times higher than human skeletal muscles, respectively, and as they continue development, they expect to produce even higher levels of performance.

"The cavatappi artificial muscles are based on twisted polymer actuators (TPAs), which were pretty revolutionary when they first came out because they were powerful, lightweight and cheap. But they were very inefficient and slow to actuate because you had to heat and cool them. Additionally, their efficiency is only about two percent," Shafer said. "For the cavatappi, we get around this by using pressurized fluid to actuate, so we think these devices are far more likely to be adopted. These devices respond about as fast as we can pump the fluid. The big advantage is their efficiency. We have demonstrated contractile efficiency of up to about 45 percent, which is a very high number in the field of soft actuation."

The engineers think this technology could be used in soft robotics applications, conventional robotic actuators (for example, for walking robots), or even potentially in assistive technologies like exoskeletons or prostheses.

"We expect that future work will include the use of cavatappi artificial muscles in many applications due to their simplicity, low-cost, lightweight, flexibility, efficiency and strain energy recovery properties, among other benefits," Shafer said.

Technology is available for licensing, partnering opportunities

Working with the NAU Innovations team, the inventors have taken steps to protect their intellectual property. The technology has entered the protection and early commercialization stage and is available for licensing and partnering opportunities. For more information, please contact NAU Innovations.

Shafer joined NAU in 2013. His other research interests are related to energy harvesting, wildlife telemetry systems and unmanned aerial systems. Feigenbaum joined NAU in 2007, and her other research interest include ratcheting in metals and smart materials. The graduate student on this project, Diego Higueras-Ruiz, received his MS in Mechanical Engineering from NAU in 2018 and will be completing his PhD in Bioengineering in Fall 2021. This work has been supported through a grant from NAU's Research and Development Preliminary Studies program.

Metaplasia is defined as the replacement of a fully differentiated cell type by another. There are several classical examples of metaplasia, one of the most frequent is called Barrett's oesophagus. Barrett's oesophagus is characterized by the replacement of the keratinocytes by columnar cells in the lower oesophagus upon chronic acid reflux. This metaplasia is considered a precancerous lesion that increases by around 50 times the risk of this oesophageal adenocarcinoma. Nonetheless, the mechanisms involved in the development of metaplasia in the oesophagus are still partially unknown.

In a new study published in Cell Stem Cell, researchers led by Mr. Benjamin Beck, (FNRS research associate and WELBIO investigator at the IRIBHM, Université libre de Bruxelles, Belgium), report the mechanisms involved in the transdifferentiation of oesophageal keratinocytes into columnar cells.

Alizée Vercauteren Drubbel and colleagues used state-of-the-art genetic tools and mouse models to dissect the molecular mechanisms by which cells from the oesophagus can participate to metaplasia. In collaboration with Prof. Sachiyo Nomura (Tokyo Medical University, Japan), they demonstrated that the reactivation of the Hedgehog pathway occurs in epithelial cells upon chronic acid reflux. The sole reactivation of this pathway in normal oesophageal cells changes them and make them look like embryonic oesophageal cells. Subsequently, a subset of these cells is converted into columnar cells. "It was really surprising to see the cells from the oesophagus slowly changing over time and getting features of other tissues just by activating a signaling pathway in vivo" comments Alizée Vercauteren Drubbel, the first author of this study.

The authors demonstrate that the hedgehog pathway alters the squamous differentiation program in virtually all the oesophageal cells but induces a full squamous-to-columnar conversion in a subset of progenitors only. Interestingly, an embryonic-like epigenetic and transcriptomic program precedes the columnar conversion, suggesting that keratinocytes need to be dedifferentiated before activating another differentiation program. Conditional knockout in vivo demonstrates that the transcription factor Sox9 plays a pivotal role in the process of columnar conversion.

In conclusion, this work highlights mechanisms modulating cellular plasticity that may constitute the very first step of transdifferentiation and metaplasia development in the oesophagus. Oesophageal adenocarcinoma incidence has dramatically increased over the past decades. This increase appears to be a result of the increased prevalence of Barrett's oesophagus. Hence, "we hope that a better understanding of the processes involved in the development of metaplasia and their progression into cancer will help detecting people with a high risk of developing cancer." comments Benjamin Beck, the last and corresponding author of this study.

Drawing on epidemiological field studies and the FrenchCOVID hospital cohort coordinated by Inserm, teams from the Institut Pasteur, the CNRS and the Vaccine Research Institute (VRI, Inserm/University Paris-Est Créteil) studied the antibodies induced in individuals with asymptomatic or symptomatic SARS-CoV-2 infection. The scientists demonstrated that infection induces polyfunctional antibodies. Beyond neutralization, these antibodies can activate NK (natural killer) cells or the complement system, leading to the destruction of infected cells. Antibody levels are slightly lower in asymptomatic as opposed to symptomatic individuals, but polyfunctional antibodies were found in all individuals. These findings show that infection induces antibodies capable of killing infected cells regardless of the severity of the disease. The research was published in the journal Cell Reports Medicine on April 21, 2021.

Nearly half of those infected with SARS-CoV-2 do not develop symptoms. Yet, the immune response induced by asymptomatic forms of COVID-19 remains poorly characterized. The extent of the antiviral functions of SARS-CoV-2 antibodies is also poorly characterized. Antibodies are capable of both neutralizing the virus and activating "non-neutralizing" functions. The latter include antibody-dependent cellular cytotoxicity (ADCC) and complement activation, which are major components of the immune response and play a key role in the efficacy of some vaccines. ADCC is a two-stage process in which infected cells are first recognized by antibodies, then destroyed by NK cells. The complement system consists of a series of plasma proteins that also enable the elimination of cells targeted by antibodies. The ability of antibodies to activate these non-neutralizing functions has been little described for SARS-CoV-2 infection so far.

The teams from the Institut Pasteur, the CNRS and the VRI (Inserm/University Paris-Est Créteil) initially developed new assays to measure the various antibody functions. They produced assays to study cell death induced by NK cells or by complement in the presence of antibodies. By analyzing cultures in real time using video microscopy, the scientists showed that NK cells kill infected cells in the presence of antibodies, demonstrating new antiviral activity employed by SARS-CoV-2 antibodies.

The scientists then examined the serum of patients with symptomatic or asymptomatic forms of COVID-19 with their new assays. They also used methods previously developed at the Institut Pasteur, such as the S-Flow assay, to detect SARS-CoV-2 anti-spike antibodies, and the S-Fuse assay, to measure the neutralization capacity of these antibodies.

"This study demonstrated that individuals infected with SARS-CoV-2 have antibodies that are capable of attacking the virus in different ways, by preventing it from entering cells (neutralization) or by activating NK cells to kill infected cells (via ADCC). We therefore use the term polyfunctional antibodies," explains Timothée Bruel, co-last author of the study and a scientist in the Institut Pasteur's Virus & Immunity Unit and at the VRI.

By comparing different groups of patients, the scientists then showed that asymptomatic individuals also have polyfunctional antibodies and that their response is slightly weaker than those of patients with moderate forms of COVID-19.

"The study reveals new mechanisms of action of SARS-CoV-2 antibodies and suggests that the protection induced by an asymptomatic infection is very close to that observed after a symptomatic infection," concludes Olivier Schwartz, co-last author of the study, head of the Virus & Immunity Unit and at the VRI.

Creativity--the "secret weapon" of Homo sapiens--constituted a major advantage over Neanderthals and played an important role in the survival of the human species. This is the finding of an international team of scientists, led by the University of Granada (UGR), which has identified for the first time a series of 267 genes linked to creativity that differentiate Homo sapiens from Neanderthals.

This important scientific finding, published today in the prestigious journal Molecular Psychiatry (Nature), suggests that it was these genetic differences linked to creativity that enabled Homo sapiens to eventually replace Neanderthals. It was creativity that gave Homo sapiens the edge, above and beyond the purely cognitive level, by facilitating superior adaptation to the environment compared to that of now-extinct hominids and providing greater resilience to ageing, injury, and disease.

The research team comprises Igor Zwir, Coral del Val, Rocío Romero, Javier Arnedo, and Alberto Mesa from the UGR's Department of Computer Science and Artificial Intelligence, the Andalusian Research Institute in Data Science and Computational Intelligence (DaSCI), and the Biohealth Research Institute in Granada (ibs.GRANADA), together with Robert Cloninger of Washington University in St. Louis and colleagues from the Young Finns Study (Finland), the American Museum of Natural History (New York), and the Menninger Clinic (Houston, Texas).

Their findings are the result of an interdisciplinary study that brings together Artificial Intelligence (AI), Molecular Genetics, Neurosciences, Psychology, and Anthropology. This is the fifth consecutive paper published by this research team in one of the most prestigious scientific journals in the area concerned with the human personality.

The 267 genes identified by these scientists as being unique to Homo sapiens are part of a larger group of 972 that are linked to personality in healthy adults and were also discovered by the same authors. In previous studies, they showed that these 972 genes are organized into three dissociable brain networks of personality traits that are responsible for learning and memory.

Evolution of genetic networks

"These networks evolved in stages. The most primitive network emerged among monkeys and apes about 40 million years ago, and is responsible for emotional reactivity--in other words, it regulates impulses, the learning of habits, social attachment, and conflict-resolution," explain the UGR researchers. Less than 2 million years ago, the second network emerged. This regulates intentional self-control: self-direction and social cooperation for mutual benefit. Finally, about 100,000 years ago, the network relating to creative self-awareness emerged.

The new study that is published this week reveals that the genes of the oldest network, that of emotional reactivity, were almost identical in Homo sapiens, Neanderthals, and chimpanzees. By contrast, the genes linked to self-control and self-awareness among Neanderthals were "halfway between" those of chimpanzees and Homo sapiens.

Most of these 267 genes that distinguish modern humans from Neanderthals and chimpanzees are RNA regulatory genes and not protein-coding genes. Almost all of the latter are the same across all three species, and this research shows that what distinguishes them is the regulation of expression of their proteins by genes found exclusively in humans. Using genetic markers, gene-expression data, and integrated brain magnetic resonance imaging based on AI techniques, the scientists were able to identify the regions of the brain in which those genes (and those with which they interacted) were overexpressed. These regions are involved in human self-awareness and creativity, and include the regions that are strongly associated with human well-being and that appeared relatively recently, phylogenetically speaking.

Superior resilience

Furthermore, the authors continue, "thanks to these genes, Homo sapiens enjoyed greater physical fitness than now-extinct hominids, providing them with a superior level of resilience to ageing, injury, and disease." Using genetic data, the researchers were able to estimate from these genes that the adaptability and well-being of Neanderthals were approximately 60%-70% those of Homo sapiens, meaning that the difference between them in terms of physical fitness was significant.

The findings have far-reaching implications in our understanding of the factors that ultimately enabled Homo sapiens to replace Neanderthals and other species in the geologically-recent past. The authors hypothesize that creativity may have given Homo sapiens selective advantages beyond the purely cognitive realm.

"Living longer and healthier lives may have prolonged the period of learning associated with youth and adolescence, which would facilitate the accumulation of knowledge. This is a remarkable characteristic of behaviourally-modern humans and an important factor in economic and social success," explain the researchers. Creativity may have encouraged cooperation between individuals in a bid to encourage success among their descendants and their community. This would have set the stage for technological innovation, behavioural flexibility, and openness to exploration, all of which were necessary for Homo sapiens to spread across the world more successfully than other human lineages.

In the five studies published to date by these researchers in Nature, they have found--and verified using multiple data sources--that human behaviour is neither entirely fixed nor solely determined by our genes, but rather is influenced also by multiple interactions with the environment. "We have the capacity to learn and adapt in light of our experience, even to the extent of modifying the expression of our genes. Human creativity, prosociality, and healthy longevity emerged as a response to the need to adapt to the harsh and diverse conditions that reigned between 400,000 and 100,000 years ago," note the UGR researchers.

This study is just one example of how the use of AI techniques and the entirely bias-free treatment of data can help to solve many puzzles about the evolution of human beings. The results obtained pave the way to the development of new lines of research that can ultimately promote human well-being and help us to adapt creatively in order to overcome critical situations.

Children with weakened immune systems have not shown a higher risk of developing severe COVID-19 infection despite commonly displaying symptoms, a new study suggests.

During a 16-week period which covered the first wave of the pandemic, researchers from Southampton carried out an observational study of nearly 1500 immunocompromised children - defined as requiring annual influenza vaccinations due to underlying conditions or medication. The children, their parents or guardians completed weekly questionnaires to provide information about any symptoms they had experienced, COVID-19 test results and the impact of the pandemic on their daily life.

The results, published in BMJ Open, showed that symptoms of COVID-19 infection were common in many of the children - with over two thirds of participants reporting at least one symptom and one third experiencing three or more symptoms simultaneously. One hundred and ten patients with symptoms undertook viral PCR tests, none of whom tested positive.

Dr Hans de Graaf from the University of Southampton who led the research said, "Whilst we cannot be certain of the prevalence of COVID-19 amongst the children who took part, because testing was only done when patients were admitted and these children were told to adhere to strict shielding measures, we can assume that any infections would have been mild cases since none of these high risk patients required hospital admissions."

More than half of the patients or parents reported high levels of anxiety at the start of the study and despite the absence of severe symptoms, these scores remained consistently high throughout the study period.

The researchers believe that these results show that widespread symptom screening for early detection of COVID-19 in not going to be useful in these cases as the children may have frequent upper respiratory tract symptoms likely to be unrelated to COVID-19.

Dr de Graaf continued, "This study was the first to observe the impact of the pandemic on children with compromised immune systems. During the first wave of the pandemic, many may have been shielding so our results suggest that either the shielding measures were effective or that immunocompromised children are less affected by COVID-19 than adults, just like healthy children."

The report also concludes that the continuous high level of anxiety among participants highlights the need to clearly define and communicate the risk of COVID-19 in children and young people, particularly as lockdown restrictions ease.

The results, exceptional first time evidence of how early flocks of domesticated sheep fed and reproduced within the Iberian Peninsula, are currently the first example of the modification of sheep's seasonal reproductive rhythms with the aim of adapting them to human needs.

The project includes technical approaches based on stable isotope analysis and dental microwear of animal remains from more than 7,500 years ago found in the Neolithic Chaves cave site in Huesca, in the central Pyrennean region of Spain. The research was coordinated from the Arqueozoology Laboratory of the UAB Department of Antiquity, with the participation of researchers from the University of Zaragoza, the Museum of Natural History of Paris, and the Catalan Institute of Human Palaeocology and Social Evolution (IPHES) in Tarragona.

"The alteration of seasonal breeding rhythms in livestock represented a huge milestone for prehistoric societies, making it possible to have access to meat and milk throughout the year, and this in turn had a huge impact on diet, on the economy and on the social organisation of the first farming communities, and set down the bases for farming strategies which continue to be carried out now. Until very recently, animal husbandry in the Neolithic period was thought to be in its initial stages, although new possibilities in biogeochemical analyses used in this study have revealed husbandry practices that were fully consolidated since the beginning of the Neolithic", says Dr Maria Saña, lecturer at the UAB Department of Prehistory and coordinator of the project.

The domestication of sheep did not occur in the Iberian Peninsula. Its agriotype, the Ovis orientalis, can be found in central and southeastern Asia. "What is surprising is the speed in which the sheep are integrated into animal husbandry strategies and their enormous economic importance in the earliest periods of the Neolithic. What we see is a rapid and successful adoption, which demonstrates that their mechanisms of adaptation to both the new environment and their new economic role were well known and controlled by a part of human communities. The selective pressures applied on the species were artificial, they pursued specific objectives and were well defined. This new evidence represents a turning point in the research into animal domestication and the origins of animal husbandry. It was made possible by the new approach that we took with this study, focused on exploring the changes in breeding and feeding of these first flocks of sheep", states Alejandro Sierra, researcher at the UAB and at the University of Zaragoza, and first author of the article recently published in Journal of Archaeological Science: Reports.

The research focused on the study of sheep rearing in the Neolithic Chaves cave (5600-5300 BCE) in the Pyrennean foothills, a site that is "spectacular for the quality and number of remains recovered. When compared to Neolithic levels of fauna, its 12,754 recognisible remains are at least threefold of what is found in other Neolithic sites on the peninsula, with domesticated sheep and goats being the most numerous species, and with the largest presence of pigs of all the Neolithic sites. All of this points to the stabling of animals and to the type of stable settlement known to be dedicated to animal husbandry, and within a large cave that had 3,000 square metres of habitable space", affirms Pilar Utrilla, professor at the University of Zaragoza and director of the archaeological interventions.

The results obtained at the Chaves site show that in the Iberian Peninsula, the birth of lambs also occurred in autumn and winter seasons, which is what is now considered to be an "out of optimal season" birthing, an aspect that contrasts significantly with the livestock regimes documented in other parts of Europe during the Neolithic, with births occurring mainly in spring. The modification of the natural birthing cycles of wild sheep affected the physiology of the animals of this species, prolonging their fertility period. That was the result of a more intense and continued human control, alterating interactions between females and males, a breeding strategy that seeked greater predictability in livestock production. "Autumn birthing in the early Neolithic in the Chaves cave would confirm the antiquity of this practice in the Western Mediterranean basin, implying a combination of the biological capacity of sheep, zootechnical skills of the agricultors, and favourable environmental conditions", states Dr Marie Balasse, researcher at the Museum of Natural History in Paris.

The study also demonstrates that this greater control and selective pressure also had an effect on the diet and movement of the species. By applying for the first time a combination of dental microwear and stable C-13 and O-18 isotope analyses on sequencial samples of second and third molar enamel bioapatite, scientists were able to detect that the flock of sheep at Chaves did not eat a greatly varied diet, neither among the sheep nor throughout the year. The results of the dental microwear show that Neolithic sheep had a more controlled diet than wild animals living in the same types of environments and which grazed on good plant covers, with still very little human impact on their lives. The sheep would graze near the cave during most of the year, and were probably also fed forage. The verification of the use of extraordinary forage is also a novelty. "The results of what the sheep from the Chaves cave ate are surprising when compared with what we expected. We were able to document diets consisting of intensive and established differences between young and adult sheep, and these characteristics can be related to a tight control on livestock production during those earliest periods of the Neolithic", states Dr Florent Rivals, ICREA research professor at the IPHES.

"The results obtained on the breeding and feeding of sheep of the Chaves cave are key for the discovery of economic systems in early farming societies of the Iberian Peninsula. The new methodology applied in this study will no doubt be fundamental in further studying animal husbandry in prehistoric times", concludes Dr Alejandro Sierra.

Researchers of the University of Barcelona, together with researchers from the University of Zurich (Switzerland) and Brown University (United States), have analysed more than 10,000 evaluations that were carried out to candidates who wish to hold a public teaching permanent in Catalonia. The objective was to study how the decision by the committee of evaluators is affected by the fact that each candidate holds a certain position in the lists of people to be assessed. The study, published in the journal Science Advances, identifies a new cognitive bias that researchers have named "generosity-erosion effect". It involves that once the evaluators have scored one candidate generously, they tend to act harsher to the subsequent ones.

Researchers considered the fact of giving someone a score of 5.00 -the minimum grade to pass- a generous gesture, since it allows people to pass the exam when they would be on the verge of failing it. In addition, it is hard for evaluators to assess the merit of a candidate at a decimal level. Once this parameter is set, the study shows that the likelihood of success decreases by 7.7% for each previous candidate that received the lowest accepted score to continue with the hiring process.

Authors provide some explanations for this generosity-erosion effect. One could be guilt-aversion: evaluators would tend to be generous and overgrade candidates who are on the verge of failing in order to avoid the feeling of guilt, but once they have given a score of 5 to some candidates this feeling of guilt is reduced and they are likely to act harsher on others. "We observed the mechanism that affects the final score is not fatigue nor the contrast with the previous candidate or the expectations of the examination board, as stated in other studies: it is mainly guilt or the generosity-erosion effect", notes Jordi J. Teixidó, researcher of the Faculty of Economics and Business of the UB and co-author of the article.

The study, also signed by the UB researcher Tania Fernández, Marc Lluís Vives (Brown University, United States) and Miquel Serra-Burriel (University of Zurich, Switzerland), uses tools from the social science game theory to interpret the results of the analysis. The selection process to hire teachers showed proper features for the study, since those candidates to be assessed were listed randomly without a certain order, and the decision was not taken individually but by a committee, which is becoming more common in selection processes.

DALLAS - April 21, 2021 - Food banks should be used more consistently rather than only during emergencies to better address food insecurity and related health issues, a joint study by researchers at UT Southwestern Medical Center and economists at the University of Dallas shows.

"The main discovery in our research is that encouraging clients and making it easier for clients to receive food frequently improves their food security, health, and well-being," says Sandi Pruitt, Ph.D., associate professor of population and data sciences at UT Southwestern, and senior author of the study. "The food banking system is predicated on the assumption that people need food pantries for emergencies only. But this is a common misconception, as many families and individuals experience food insecurity for months or years at a time and it's more of a chronic condition."

The researchers calculated that a 10 percentage-point increase in the frequency of food pantry visits led to a 5.7 percent reduced likelihood of food insecurity and a 6.2 percent reduction in likelihood of poor health.

In 2018, 11.1 percent of U.S. households reported being food insecure, defined as inconsistent access to adequate food due to lack of financial or other resources, the researchers report. Food insecurity across the country has increased to new historical highs during the COVID-19 pandemic.

"Food insecurity rates often spike during an economic recession. Following the 2007-2009 recession, the nationwide food insecurity rate took 11 years to return to the pre-recession level," says lead author Tammy Leonard, Ph.D., an economist at the University of Dallas. "This is an indication that we need to rethink our systems and processes for addressing this fundamental need."

Researchers evaluated an innovative model used at Crossroads Community Services, a food pantry and distribution system located in southern Dallas County that focuses on nourishing families through nutritious food items to power dietary change for improved health. Crossroads partners with smaller community organizations to distribute food at multiple locations such as public housing facilities, churches, and community centers, and requires clients to pre-enroll for monthly pickups.

"What we observed in Dallas is that Crossroads has made food more accessible to clients and has also encouraged clients to come back regularly, and that signals that they should be seeking support. We hope that this can be a policy change in food distribution settings across the U.S.," Pruitt says. "The food banking system and everything in the food assistance sector is more important than ever right now, and we really need to maximize the importance of these food assistance programs on clients to ensure that everyone has enough food to eat."

UNIVERSITY PARK, Pa. -- A new approach to gene editing using the CRISPR/Cas9 system bypasses disease-causing mutations in a gene, enabling treatment of genetic diseases linked to a single gene, such as cystic fibrosis, certain types of sickle cell anemia, and other rare diseases. The method, developed and tested in mice and human tissue cultures by researchers at Penn State, involves inserting a new, fully functional copy of the gene that displaces the mutated gene.

A proof-of-concept for the approach is described in a paper appearing online April 20 in the journal Molecular Therapy.

The CRISPR/Cas9 system has allowed promising new gene therapies that can target and correct disease-causing mutations in a gene. In this process, Cas9--a bacterial protein--cuts DNA at a specific location, where the genetic sequence can then be edited, trimmed, or a new sequence inserted before the DNA is repaired. However, there are two main limitations to current repair strategies. First, the common repair strategy, called "homology-directed repair," requires using specific proteins within the cell that are only present during cell division, which means the gene repair process cannot be used in most adult tissues where cell division occurs rarely.

"The second challenge stems from the fact that even when a disease is caused by a single gene, it can result from a variety of different mutations within that gene," said Douglas Cavener, professor of biology at Penn State and senior author of the paper. "With homology-directed repair, we'd need to design and test the strategy for each and every one of those mutations, which can be expensive and time-intensive. In this study, we designed an approach called Co-opting Regulation Bypass Repair (CRBR), which can be used in both dividing and non-dividing cells and tissues and for a spectrum of mutations within a gene. This approach is especially promising for rare genetic diseases caused by a single gene, where limited time and resources typically preclude design and testing for the many possible disease-causing mutations."

CRBR takes advantage of the CRISPR/Cas9 system and a cellular repair pathway called "non-homologous end joining" to insert a genetic sequence between a mutated gene's promoter region--the genetic sequence that controls when and where the gene is functional--and the mutated portion of the gene. The newly inserted sequence contains a condensed version of the normal gene that is used in place of the mutated version. A terminator sequence at the end of the inserted sequence prevents the remaining downstream mutated gene from being used. Because CRBR does not rely on the proteins required by homology-directed repair, it can be used in all types of adult tissues.

"Our approach co-opts the native promoter for a gene," said Jingjie Hu, a graduate student at Penn State and first author of the paper. "This means that the newly inserted gene will be expressed at the same times and at appropriate levels within the cell as the gene it is replacing. This is an advantage to other types of gene therapies, which rely on an external promoter to drive high levels of expression of the gene that could lead to negative effects if too much is produced or if essential regulation response is missing under certain physiological conditions."

The research team conducted a series of proof-of-concept experiments to demonstrate the utility of this method. They first focused on the PERK gene, mutations in which can lead to a rare disease called Wolcott-Rallison syndrome. The syndrome results when copies of the gene inherited from both parents have mutations--it is a "recessive" disease--and can cause neonatal diabetes, skeletal problems, growth delay, and other symptoms.

The researchers inserted the PERK gene in healthy mice using CRBR and bred them with mice that had a mutation in the gene. The resulting mice, which contained one CRBR-edited PERK gene and one mutated PERK gene, did not have the typical abnormalities associated with the syndrome, indicating that the CRBR-edited gene can rescue PERK gene function in a mouse model of the Wolcott-Rallison syndrome.

Next, the researchers tested the CRBR method in human tissues in the laboratory, in this case focusing on the insulin gene. They inserted a green fluorescent protein marker gene sequence between the insulin gene promoter and the insulin coding sequence in human cadaver cells. This experiment resulted in the expression of the fluorescent protein in insulin secreting cells, but not other cell types, which suggests the new sequence was strictly regulated under the control of insulin promoter.

"Our results demonstrated that CRBR gene repair can restore PERK gene function in mice and revealed the potential utility of CRBR for gene repair in human tissue," said Hu.

The researchers note that gene editing with CRISPR/Cas9 can be error prone. For example, homology-directed repair-based strategies could potentially produce damaging mutations in the coding sequence if repair does not happen properly. With CRBR, the researchers target the insertion within a region of the gene that does not code for protein, which should be more tolerant of these errors.

"Gene therapies such as CRBR that utilize CRISPR/Cas9 continue to face the challenge of delivery repair machinery into the cells of interest," said Cavener. "One promising development is to isolate cells or tissues from the afflicted patient, repair a mutant gene in the laboratory, and then transplant the repaired cells or tissues back into the patient. We hope that, as researchers continue to improve delivery methods, CRBR can be utilized to treat Wolcott-Rallison syndrome as well other human genetic diseases."

The number of solar panels within shortest distance from a house is the most important factor in determining the likelihood of that house having a solar panel, when compared with a host of socio-economic and demographic variables. This is shown in a new study by scientists using satellite and census data of the city of Fresno in the US, and employing machine learning. Although it is known that peer effects are relevant for sustainable energy choices, very high-resolution data combined with artificial intelligence techniques were necessary to single out the paramount importance of proximity. The finding is relevant for policies that aim at a broad deployment of solar panels in order to replace unsustainable fossil fueled energy generation.

"It's almost like if you see a solar panel from out of your window, you decide to put one on your own roof as well," says study author Leonie Wenz from the Potsdam Institute for Climate Impact Research (PIK) in Germany. "Of course, one might think that other factors are more relevant, for instance income or educational background, or word-of-mouth within the same social network such as a school district. So we compared all these different options, and we've been amazed by the outcome. It turns out that, no, geographical distance really is the most important factor. The more panels there are within a short radius around my house, the more likely I'm of having one, too."

Peer effect halves over the distance of a football field

"The likelihood of putting a solar panel on your roof roughly halves over the distance of a football field", says Anders Levermann from PIK and Columbia University's LDEO in New York who is also an author of the study. "The contagion effect is strongest for a short radius around a home with a solar panel and decreases exponentially the farther away the panels are. It is a remarkable robust feature that is most pronounced in low-income neighborhoods.

The scientists just made the data speak. "We combined population census data for every district with high-resolution satellite data that is able to identify all the solar panels in Fresno," explains study author Kelsey Barton-Henry from PIK. "Then we trained several machine learning algorithms to find the relation between people's socio-economic setting and their likelihood of having a solar panel."

"Seeding solar panels where few exist may flip a community"

"The findings suggest that seeding solar panels in areas where few exist, may flip a community," concludes Levermann. "If more solar panels lead to more solar panels that may generate a kind of tipping point - a good one this time. The climate system has a number of extremely dangerous tipping points from the West Antarctic ice sheet to the North Atlantic Current." Wenz adds: "Hence, researching climate decisions to identify positive social tipping points, both small and big ones, is important to ensure a safe tomorrow for all."

Coronavirus researchers led by Professor Rolf Hilgenfeld of the University of Luebeck and PD Dr. Albrecht von Brunn of the Ludwig-Maximilian Universitaet (LMU) in Munich have discovered how SARS viruses enhance the production of viral proteins in infected cells, so that many new copies of the virus can be generated. Notably, coronaviruses other than SARS-CoV and SARS-CoV-2 do not use this mechanism, which may therefore provide a possible explanation for the much higher pathogenicity of the SARS viruses. The findings appear in the EMBO Journal.

Coronaviruses that cause harmless colds in humans were discovered more than 50 years ago. When it emerged in 2002/2003, the SARS coronavirus was the first coronavirus found to cause severe pneumonia in infected people. Comparisons of the RNA genomes of innocuous coronaviruses with those of the SARS coronavirus permitted researchers to identify a region that only occurred in the latter, and was called the "SARS-unique domain" (SUD). Such genomic regions and their protein products might be linked to the extraordinary pathogenicity of SARS coronavirus and its cousin, the COVID-19 virus SARS-CoV-2. 

The research groups led by Hilgenfeld and von Brunn showed that the SUD proteins of these two viruses interact with a human protein called Paip-1, which is involved in the first steps of protein synthesis. Together with Paip-1 and other proteins in human cells, SUD apparently binds to the ribosomes, the molecular machines that are responsible for protein synthesis in cells. This would lead to an enhancement of the production of all proteins, both those of the host cell and those of the virus. However, in cells infected with SARS-CoV or SARS-CoV-2, the messenger RNA molecules that code for host proteins are selectively destroyed by a viral protein named Nsp1. As a result of this complicated process, the infected cell predominantly produces viral proteins, so that many new copies of the virus can be created.

Albrecht von Brunn's research group discovered the interaction between the proteins SUD and Paip-1 several years ago. "Being an experienced coronavirologist, I knew that one has to inspect the special regions of the SARS genome when trying to understand this virus," he says.

The discovery made by the Munich researchers was of great interest to Hilgenfeld, whose research group had already elucidated the three-dimensional structure of the SUD protein some years previously. The two research groups teamed up. Dr. Jian Lei in Hilgenfeld's group, meanwhile a group leader at Sichuan University in Chengdu (China), succeeded in crystallizing the complex formed by SUD and Paip-1 and determining its three-dimensional structure by X-ray crystallography. And co-first author Dr. Yue "Lizzy" Ma-Lauer of von Brunn's group characterized the complex of the two proteins and its function using a variety of cell-biological and biophysical methods.

"Interaction studies of this kind between coronavirus proteins and proteins of the infected human cell will help us understand how the viruses change key functions of the cell to their own benefit," says Hilgenfeld. The project was supported by the German Federal Ministry of Education and Research (BMBF) and by the German Center for Infection Research (DZIF).

After pouring beer into a glass, streams of little bubbles appear and start to rise, forming a foamy head. As the bubbles burst, the released carbon dioxide gas imparts the beverage's desirable tang. But just how many bubbles are in that drink? By examining various factors, researchers reporting in ACS Omega estimate between 200,000 and nearly 2 million of these tiny spheres can form in a gently poured lager.

Worldwide, beer is one of the most popular alcoholic beverages. Lightly flavored lagers, which are especially well-liked, are produced through a cool fermentation process, converting the sugars in malted grains to alcohol and carbon dioxide. During commercial packaging, more carbonation can be added to get a desired level of fizziness. That's why bottles and cans of beer hiss when opened and release micrometer-wide bubbles when poured into a mug. These bubbles are important sensory elements of beer tasting, similar to sparkling wines, because they transport flavor and scent compounds. The carbonation also can tickle the drinker's nose. Gérard Liger-Belair had previously determined that about 1 million bubbles form in a flute of champagne, but scientists don't know the number created and released by beer before it's flat. So, Liger-Belair and Clara Cilindre wanted to find out.

The researchers first measured the amount of carbon dioxide dissolved in a commercial lager just after pouring it into a tilted glass, such as a server would do to reduce its surface foam. Next, using this value and a standard tasting temperature of 42 F, they calculated that dissolved gas would spontaneously aggregate to form streams of bubbles wherever crevices and cavities in the glass were more than 1.4 μm-wide. Then, high-speed photographs showed that the bubbles grew in volume as they floated to the surface, capturing and transporting additional dissolved gas to the air above the drink. As the remaining gas concentration decreased, the bubbling would eventually cease. The researchers estimated there could be between 200,000 and 2 million bubbles released before a half-pint of lager would go flat. Surprisingly, defects in a glass will influence beer and champagne differently, with more bubbles forming in beer compared with champagne when larger imperfections are present, the researchers say.

(Boston)--A major obstacle in understanding and treating posttraumatic stress disorder (PTSD) is its clinical and neurobiological heterogeneity. In order to better treat the condition and address this barrier, the field has become increasingly interested in identifying subtypes of PTSD based on dysfunction in neural networks alongside cognitive impairments that may underlie the development and maintenance of symptoms.

VA and BU researchers have now found a marker of PTSD in brain regions associated with emotional regulation. "This marker was strongest in those with clinically impaired executive function or the ability to engage in complex goal-directed behavior," explained corresponding author Audreyana Jagger-Rickels, PhD, a post-doctoral scientist in the Boston Attention and Learning Lab (BALLAB) at the VA Boston Healthcare System.

The study included 271 Veterans participants in the Translational Research Center for TBI and

Stress Disorders (TRACTS) at VA Boston, who had been deployed to post-9/11 conflicts and completed a functional MRI scan that measures the communication between brain regions. The Veterans also completed tests that measured PTSD and cognitive (neuropsychological) functioning, including executive functioning.

The researchers found that Veterans with greater PTSD severity had an increased disruption between their cognitive control network (frontal parietal control network) and their emotional processing network (limbic network). Upon further investigation, they found that those with clinically impaired executive function had the greatest disruption to this brain marker of PTSD.

"This study provides preliminary evidence for a "neurocognitive" subtype of PTSD, specifically that a combination of cognitive and brain signatures may identify a subset of people with PTSD that could be unique," said senior author Michael Esterman, PhD, principal investigator, National Center for PTSD at VA Boston Healthcare System and associate professor of psychiatry at Boston University School of Medicine.

According to the researchers these findings suggest that if someone presents with PTSD and impaired executive function, that they may also have a unique brain marker related to emotional regulation. "These individuals may respond best to specific treatment strategies but may also have difficulty engaging in treatments that require high levels of emotional regulation and executive functioning," added Jagger-Rickels.

The researchers hope this study will help identify those who will benefit from specific treatments for PTSD and may lead to new innovative treatments that target cognitive and brain functioning. "Ultimately, diagnosing and treating individuals based on their own unique clinical and biological profile, rather than simply based a broad diagnosis, would be the goal," said Esterman.