Culture

Effective contact tracing and epidemic control measures are essential for safe opening of schools during COVID-19 pandemic, according to two studies published simultaneously in The Lancet Child & Adolescent Health journal.

Modelling the impact of UK schools reopening in September, one study suggests that a second COVID-19 wave could be avoided in the UK, if accompanied by a test-trace-isolate programme with sufficiently broad coverage. The second study, analysing data collected between January and April 2020 in New South Wales (Australia), finds low levels of transmissions in schools and nurseries when control measures are in place.

Children across the globe have been affected by school and nursery closures during the first wave of the COVID-19 pandemic as governments grapple with efforts to reduce transmission. However, school closures may have detrimental effects on children's physical and mental health and wellbeing and have the potential to increase inequality.

There is a lack of evidence on the role of schools in the transmission of coronavirus, with the majority of existing data based on modelling and very few studies using real-world data from schools to investigate outbreaks. Although much still remains unknown about transmission in educational settings, both studies published today point to the importance of the broader context under which schools are re-opened, as well as to the need for further research on the levels of transmission in children and teenagers.

Modelling reopening of UK schools

The modelling study, led by researchers at UCL and the London School of Hygiene and Tropical Medicine, provides the first estimates on the levels of test-trace-isolate coverage needed for schools and wider society to reopen while avoiding a second epidemic wave in the UK.

Using workplace, community, demographic and epidemiological data, the authors modelled six different scenarios of school reopening. These included full time and a part-time rota system with half of students attending school on alternate weeks, each within three testing scenarios reflecting various levels of contact tracing and testing. Alongside school reopening, the model included the relaxation of measures across society, which they assumed would accompany one another. For each scenario, they estimated the number of new infections and deaths, as well as the effective reproduction number (R).

The results of the modelling suggest a second wave in the UK might be avoided with increased levels of testing (between 59% and 87% of symptomatic people tested at some point during an active SARS-CoV-2 infection), and effective contact tracing and isolation.

For effective contact tracing and isolation, assuming 68% of contacts could be traced, 75% of individuals with symptomatic infection would need to be diagnosed and isolated if schools return full-time in September, or 65% if a part-time rota system were used. If only 40% of contacts could be traced, these figures would need to increase to 87% and 75%, respectively.

However, if levels of diagnoses and contact tracing fall below this across the UK population, reopening of schools together with gradual relaxing of the lockdown measures are likely to result in a secondary wave that would peak in December, 2020, if schools open full-time in September, and in February, 2021, if a part-time rota system were adopted in September.

In either of these scenarios of continual gradual relaxation control measures and insufficient test-trace-isolate, the authors caution that the second wave could result in the reproduction number (R) rising above 1 and a resulting secondary wave of infections 2 to 2.3 times the size of the original COVID-19 wave.

For the main study, the model assumed that children were as infectious as adults. However, since the evidence that the level of infectiousness in children compared to adults is non-conclusive, they also re-ran the model with the assumption that children and young people were 50% as infectious as adults, with the results remaining.

Dr Jasmina Panovska-Griffiths, UCL/Oxford, who lead the study, commented "Our modelling suggests that with a highly effective test and trace strategy in place across the UK, it is possible for schools to reopen safely in September. However, without sufficient coverage of a test-trace-isolate strategy the UK risks a serious second epidemic peak either in December or February. Therefore, we urge the government to ensure that test-trace-isolate capacity is scaled up to a sufficient level before schools reopen." [1]

She continues, "It's important to note that our model looked at the effects of school reopening alongside the loosening of the restrictions across society, as school reopening is likely to go hand in hand with more adults returning to work and other relaxed measures across society. Therefore, our results are reflective of a broader loosening of lockdown, rather than the effects of transmission within schools exclusively, suggesting an effective test-trace-isolate offers a feasible alternative to intermittent lockdown and school closures to control the spread of COVID-19." [1]

Professor Chris Bonell, LSHTM, one of the senior authors on the study, says, "Our study should not be used to keep schools shut because of a fear of a second wave but as a loud call to action to improve the infection control measures and test and trace system so we can get children back to school without interrupting their learning again for extended periods of time. This is even more important in the context of opening up other areas of society" [1]

The authors note some limitations of their study, highlighting that, as with any modelling study, their model rests on a series of assumptions. Although they model scenarios to resemble the UK, some of the assumptions are based on data from different settings.

Although rates of asymptomatic transmission are currently unclear this model assumes that asymptomatic infections account for 30% of onward-transmitted infections. They also note that their study does not account for the behaviour of young people who are not in school and have not assumed increased social mixing outside schools.

COVID-19 transmission in 25 schools and nurseries in New South Wales, Australia

A second, observational study, also published in The Lancet Child & Adolescent Health journal, looked at real world-data from January to April tracking COVID-19 spread within 25 schools and nurseries in New South Wales, Australia. The study finds that the risk of children and staff transmitting the virus in these educational settings was very low when contact tracing and epidemic management is in place.

Although 27 children or teachers went to school or nursery while infectious, only an additional 18 people later became infected (out of 1,448 contacts - a secondary attack rate of 1.2%).

The findings suggest that schools and nursery (known in Australia as early childhood education and care; ECEC) centres do not pose a high risk for onward transmission of coronavirus where effective contact testing strategies are in place.

Unlike many other countries, Australia, which had comparatively low COVID-19 incidence during the first wave of the epidemic, kept schools open during the first wave, with guidance in place for physical distancing and hygiene.

"Our findings are the most comprehensive data that we have yet on SARS-CoV-2 transmission in schools and early years education settings," says Professor Kristine Macartney, Director of the National Centre for Immunisation Research and Surveillance and with the University of Sydney, Australia. [1]

The study looked at laboratory-confirmed COVID-19 cases in the state of New South Wales and identified all staff, and children aged 18 and under who attended school or nurseries while infectious (including 24 hours before the onset of symptoms), using the state's centralised reporting system (the NSW Notifiable Conditions Information Management System).

All cases or their guardians were interviewed at diagnosis to track their attendance at school or nursery as well as any contact with other people during the time that they were infectious. All 3,103 schools and approximately 4,600 nurseries in New South Wales were eligible for analysis, which took place over a three-month period from the first COVID-19 case in 25 January to 10 April 2020 (end of school term).

Close contacts - defined as those with face to face interaction for a minimum of 15 minutes or 40 minutes in an indoor space with an infected person - were identified using timetables, interviews with parents and school officials. Once identified, they were monitored (with regular phone calls) and asked to quarantine for 14 days. If they began to show symptoms, they were asked to take a test, allowing the authors to calculate how many secondary transmissions were associated with each primary case identified.

Overall, 12 children and 15 adults were found to have attended schools or nurseries while infectious. These attendances took place across 15 schools and 10 nurseries.

Contact tracing identified 1,448 close contacts who were followed up with regular phone calls and instructed to be tested if they showed symptoms. 633 (43.7%) of these people were tested for COVID-19 after either showing symptoms or if they opted for a test (using either nucleic acid or antibody testing).

Of the 633 close contacts who were tested following symptoms, 18 were found to have COVID-19, meaning that 1.2% of all close contacts (1,448) were confirmed positive.

These 18 secondary transmissions happened in three schools and one nursery. The nursery outbreak was large, and involved transmission from one adult to six adults and seven children (35.1%; 13/37 contacts). Removing this one outbreak from the analysis resulted in a rate of one infection per 282 (0.4%) close contacts for education settings overall.

In a subset of seven schools and nurseries that underwent additional investigations including antibody testing, symptom surveys and extra nucleic acid testing for the virus, the child-to-child transmission rate was found to be 0.3%, and 1.0% for child-to-staff. The rate of staff-to-child transmission was 1.5% and staff-to-staff was 4.4%, suggesting that children are less likely than adults to spread the virus.

Of the total of 1.8 million children in New South Wales, the study identified only 98 children who were infected, accounting for 3.2% of total COVID-19 infections, confirming low rates of disease in this age group.

"The study adds valuable data but it is important to view these findings in the context of the NSW outbreak. It may be that higher rates of transmission occur in areas with higher levels of infection and where contact tracing and public health measures were not as rigorous as in Australia, where borders were closed and quarantine measures were strongly enforced. Schools were also closed temporarily for thorough cleaning if a pupil or staff member was found to be infected." says Professor Macartney. [1]

The one outbreak in a nursery setting was complex and occurred early in the outbreak, when criteria for testing was more narrow. The study suggests that the transmission stemmed from staff rather than children attending the centre, and a number of children were asymptomatic.

The authors caution that there are some limitations to the study, most notably that the majority of close contacts were tested after developing symptoms, suggesting that some asymptomatic or milder cases may have been missed. Furthermore, children were encouraged to stay home for distance learning from March 22 and although schools did remain open, there was a drop in school attendance from 90% to approximately 5% immediately before the school holidays in April.

In a linked commentary discussing both articles, Professor W John Edmunds, LSHTM, says, "Both studies give potential options for keeping schools open and show the clear importance of adequate contact tracing and testing. Macartney and colleagues suggest that educational settings can remain open provided measures, such as contact tracing, quarantine, and even school closures, are in place to limit spread when cases occur. Panovska-Griffiths and colleagues suggest that the safe reopening of schools in the UK could occur if the TTI programme is greatly improved. However, many questions remain, including whether there are age-related differences in susceptibility and the likelihood of transmission between children and adolescents. We urgently need large-scale research programmes to carefully monitor the impact of schools reopening, as Public Health England's sKID study aims to do. Only in this way can we take the most appropriate measures to mitigate the risks and allow us to reassure parents, pupils, and teachers alike that schools are safe to attend. There are no quick fixes to this terrible pandemic. However, it is becoming increasingly clear that governments around the world need to find solutions that allow children and young adults to return to full-time education as safely and as quickly as possible."

Shakespeare once wrote that the "eyes are the window to your soul." But scientists have found it challenging to peer into the brain to see how it derives meaning from a look into another's eyes.

Psychologists at Yale and Harvard have now found a new way to study this mystery by examining the universal and embarrassing tendency to avert one's gaze when caught looking at someone else.

In almost all cases, people instinctually follow the gaze of another. But the psychologists found an exception in the socially awkward situation in which a person caught staring averts their eyes: A third-party observer does not reflexively follow their gaze.

The researchers conclude that the brain tells the observer that there is no significance to the location where the embarrassed party has turned their attention.

"The brain is a lot smarter than we thought," said Yale's Brian Scholl, professor of psychology and senior author of the paper, published the week of Aug. 2 in the journal Proceedings of the National Academy of Sciences. "The brain is reading people's minds, not just where they are looking."

In a series of experiments, Scholl, Clara Colombatto of Yale, and Yi-Chia Chen of Harvard showed that the brain does not always turn the eyes to the focus of someone else's gaze, but only does so when it assesses that the gaze is "socially significant."

"Eye and head movements after you're 'caught' during gaze deflection do not automatically orient others' attention -- presumably because the brain can tell that such looks aren't directed toward anything in particular, but rather are just directed away from the person who was caught staring," Scholl said. "This shows how the brain is specialized not to perceive others' eyes, but rather to perceive the mind behind the eyes."

Understanding eye movement is particularly valuable during a pandemic, when they are all but the only facial feature visible above a mask, the authors said.

"This serves as a case study of both how social dynamics can shape visual attention in a sophisticated manner and how vision science can contribute to our understanding of common social phenomena," they write.

New Haven, Conn. -- Sarecycline, a drug approved for use in the United States in 2018, is the first new antibiotic approved to treat acne in more than 40 years. Now, researchers at Yale and the University of Illinois-Chicago have discovered how its unique chemical structure makes it effective.

Their new study is the most detailed biological analysis to date for sarecycline, one of a number of tetracycline antibiotics (such as doxycycline and minocycline) used to treat acne. The researchers report findings Aug. 3 in Proceedings of the National Academy of Sciences.

They found that unlike other tetracycline drugs, sarecycline binds to messenger RNA (mRNA) -- molecules within a cell that provide a code for making proteins -- in bacterial ribosomes. Ribosomes, found in all living cells, link amino acids together.

Sarecycline and other tetracyclines treat acne by inhibiting bacterial protein synthesis. They block ribosome function in Cutibacterium acnes, the pathogenic bacterium in acne.

"We show that the structure of sarecycline matters," said Dr. Christopher Bunick, associate professor of dermatology at Yale and co-corresponding author of the study. "This mode of action has never been seen before in this class of antibiotics, and suggests that sarecycline has unique properties among the tetracycline class."

Importantly, the researchers found an explanation for why sarecycline has such a low drug-resistance profile, boosting its effectiveness. Sarecycline thwarts TetM, a ribosome guardian protein that protects bacteria from outside interference.

Bunick and his team said the broader implication of the study is that structural knowledge of tetracycline compounds could be used to engineer better antibiotics.

"This could result in therapies with better or longer-lasting efficacy, fewer side effects, and lower drug resistance," Bunick said. "Future agents could be used not just in acne, but potentially in other skin disorders and infections as well."

For patients, especially those living with chronic conditions, nonadherence to prescription medicines due to cost is a common problem. By not filling prescriptions, skipping doses, delaying refills, or splitting pills, patients risk compromising the therapeutic benefit of their treatments. To understand the extent of this problem, Jamie Daw, assistant professor of Health Policy and Management at Columbia University Mailman School of Public Health and colleagues at the University of British Columbia, studied survey data from 11 high-income countries. They found that the largest disparities for non-adherence occurred among younger women in the U.S. The study results are published in the August issue of the journal Health Affairs.

The authors compared cost-related nonadherence among younger (ages 18-64) and older men and women (ages 65 or more) in eleven high-income countries including Australia, Canada, France, Germany, the Netherlands, New Zealand, Norway, Sweden, Switzerland, the United Kingdom, and the United States. They found that the largest disparities for non-adherence occurred among U.S. women compared with men -- 54 percent higher - compared to Canada at 33 percent and Australia at 17 percent higher.

Their analysis also showed that in the U.S., one in four younger women reported cost-related nonadherence compared with one in seven younger men, with no significant female-differences among older adults in any of the eleven countries.

"Prescription drug coverage systems --like those in the U.S. and Canada--that rely on employment-based insurance or require high patient contributions may disproportionally affect women, who are less likely to have full-time employment and more likely to be lower income. The disparities we found in access to medicines may produce health disparities between men and women that should be further explored," said Daw.

NASA's satellites were working overtime as they snapped pictures of the large Apple Fire in Banning Canyon near San Bernardino, California on Aug. 02, 2020. This fire began on July 31, 2020 and the cause of the fire is still under investigation. To date the fire has consumed 20,516 acres and is 5% contained.Much of the northern and eastern edge of the fire is located in very steep, rugged hillsides not easily accessible to firefighting vehicles. Low humidity, high temperatures, low moisture content in the surrounding vegetation and winds all contribute to the spread of fire once it breaks out. This fire is burning in an area that haso not had fire activity in recent years leaving it with plenty of fuel for growth. Hot, dry conditions are expected to continue in the area.

Soils harbour a substantial part of the world's biodiversity, yet data on the patterns and processes taking place below ground does not represent all relevant ecosystems and taxa. For example, tropical and subtropical regions largely remain a blind spot when it comes to soil biodiversity. This is one of the results of a new study published in Nature Communications and led by scientists from the German Centre for Integrative Biodiversity Research (iDiv), the Martin Luther University Halle-Wittenberg (MLU) and Leipzig University (UL).

Soils contribute to many crucial ecosystem functions and services including climate regulation, nutrient cycling, and food production. To support their conservation, it is essential to know which macroecological patterns are related to the functioning of soil organisms - only then can we understand the effects of global change drivers. Such analyses need to represent the diversity of environmental conditions that can be found worldwide. Despite the mounting number of soil ecology studies, major gaps still exist in our understanding of soil biodiversity.

To identify these environmental gaps, an international team of researchers led by the German Centre for Integrative Biodiversity Research (iDiv) performed an analysis of soil macroecological studies and over 17,000 sampling sites across the globe. "This effort involved researchers from all continents and we found not only large gaps in important spatial, environmental, and taxonomic representation, but also an almost complete absence of temporally explicit data," said lead author Dr Carlos Guerra, researcher at iDiv and MLU. Given the many legal and logistic limitations related to soil macroecology, researchers often prefer to expand their number of sites rather than seeing what is happening over time. "This prevents scientists from properly assessing the effects of climate change on soil organisms and functions, but also stakeholders from taking appropriate management actions to preserve and maintain important ecosystem services, such as food and water security, for which soils are the main provider."

Lack of data for most diverse places on Earth

In contrast to other ecosystems like aboveground terrestrial, one major issue with respect to soil biodiversity is that the data does not represent all ecosystems. Gaps exist, for example, for most tropical systems: soil biodiversity and function data is scarce or even non-existent in tropical and subtropical regions, which are among the most megadiverse places on Earth. The researcher found that temperate biomes (especially broadleaved mixed forests and Mediterranean) contain more sampling sites than tundra, flooded grasslands and savannas, mangroves, and most of the tropical biomes. "This likely reflects differences in funding availability and research focus and infrastructures across countries," said Carlos Guerra.

At the same time, for many of the best-represented regions across the globe, there is rarely a complete picture of the hidden life below the surface. Instead, records are often dominated by one or two taxa such as bacteria and fungi. "We all heavily depend on the biodiversity under our feet - it is time to better understand this underexplored part of biodiversity," said Professor Nico Eisenhauer, head of the Experimental Interaction Ecology research group at iDiv and UL.

Understanding what is happening - and why

In a changing world where land-use intensity, desertification, and rapid climate change are forecast to increase, it is important to understand if and to what extent biodiversity changes are happening in the soil. This is particularly relevant to assess the links between changes in biodiversity and ecosystem function: for example, whether changes in biodiversity occur because of changes in function, coupled with them, or despite them.

The researchers highlight the need for action to facilitate a global soil monitoring system that overcomes the current limitations. "This study is a milestone revealing the status quo and informing future soil biodiversity monitoring," said Nico Eisenhauer. "Now, the next steps require two complementary pathways: making data available and standardized for further research and globally standardized sampling. Something that we are already working to put in place," said Carlos Guerra Ultimately, this could help track the fulfilment of global or national biodiversity targets, and support policy and decision-making.

Social networks have been found to influence academic performance: students tend to perform better with high-performers among their friends, as some people are capable of inspiring others to try harder, according to Sofia Dokuka, Dilara Valeyeva and Maria Yudkevich of the HSE University. Their paper was published in PLOS ONE.

Most researchers in educational sciences recognize four factors affecting student academic performance, namely: the family's socioeconomic status, the time spent on independent learning and preparation for classes, the time spent working on a job or practicing a hobby and the university or school environment.

However, recent empirical studies indicate that the role of the social environment may be underestimated, as classmates can greatly influence one another's behaviour and academic success.

Most studies question the role of social environment. Yet the value of many such studies is limited due to serious design flaws - such as viewing a random group of classmates as one's social network or assuming that a student's position in his or her social network is static. Rather than being random, one's social network is a product of conscious and dynamic choice. Social networks, particularly among college freshmen, can change considerably over time - e.g. a student can break up with an underachieving friend and seek the company of A-graders.

Using 2013-2014 data on the social networks of 117 first-year students of the Faculty of Economics at a Russian university, researchers examined whether academic performance plays a role when students choose their friends and tutors among classmates. They also examined how friends and tutors influence each other's performance during their studies.

They analysed the data using stochastic actor-based modeling to address the dynamics and other nuances of social group members' behavior.

According to the authors, in choosing friends, students do not usually consider academic performance, but over time - often in the middle of the academic year - all members in a peer group tend to perform at about the same level.

'With the use of data on the dynamics of friendship, assistance and academic performance networks, we monitor essential differences in the functionality of these connections. We have proven that asking for help with studies does not lead to growth in performance. However, friendship with those who get good grades does,' said Sofia Dokuka, https://www.hse.ru/en/staff/sofi Research Fellow at the HSE Institute of Education.

Thus, most students who surrounded themselves with high-achievers improved their performance over time. The opposite was also true - those who befriended underachievers eventually experienced a drop in grades.

According to the authors, while underachievers have a stronger influence on their networks, high performers tend to gain popularity and expand their influence over time, particularly by helping other students with their studies.

Men were found to have larger networks than women, and all students were more likely to be friends with those whom they had known before college, classmates of the same gender, and members of their study group.

Key Takeaways:

Larger daily deal platforms with bigger consumer marketplaces can exert more bargaining power during negotiation.

Merchants can build their own businesses by choosing the right daily deal platforms. Merchants' choice of a platform depends on their characteristics and the consumer base of the platform.

Underdog platforms help merchants by providing an alternative outlet in price negotiation.

CATONSVILLE, MD, August 3, 2020 - If you've ever taken advantage of a nice discount thanks to a promotion from Groupon or LivingSocial, you've tapped the power of the daily deal market yourself. You, the consumer, benefited from the prior bargaining that took place between that big online platform and the merchant, resulting in a lower price for you.

Researchers from the University of Maryland and Harvard University analyzed the bargaining process between those daily deal platforms and merchants to identify the trade-offs made by both parties during the transaction to achieve their goals. While merchants may have less leverage and sacrifice certain net profits for the short term when selling their goods or services on the larger platforms, they can win in the long run by adding new customers and creating the opportunity for future sales to a larger customer base.

The research study, "Price Bargaining and Competition in Online Platforms: An Empirical Analysis of the Daily Deal Market," published in the July issue of the INFORMS journal Marketing Science, is authored by Lingling Zhang of the University of Maryland and Doug J. Chung of Harvard University.

"We focused on price bargaining and platform competition," said Zhang. "We asked two questions: What are the determinants of price setting and profit splitting between platforms like Groupon and LivingSocial and their suppliers? And, to what extent does price bargaining affect competition and market outcomes?"

To answer those questions, the authors used data from the U.S. daily deal market with a specific focus on the Groupon and LivingSocial platforms, each sell a daily assortment of discounted goods and services, and in doing so, they connect local merchants with consumers.

"On the demand side, consumers make a multistage decision," said Chung. "They first choose the deal platform, and then they choose which deal to purchase. On the supply side, platforms and merchants negotiate terms. The platform considers not only how much revenue can be generated from each deal, but also the extent to which the deal can help grow its customer base. For the merchant, it evaluates both the current deal revenue and the future payoff by retaining the newly acquired customers."

The researchers found that, while smaller platforms cannot offer access to a consumer market like larger platforms can, they are willing to leave more room for merchants on profit splitting. So, the long-term results of working with smaller platforms can be better for some merchants.

"We compared Groupon, the larger online platform, to LivingSocial, the smaller one, and found that LivingSocial can compensate for its smaller size by offering higher share of profit to merchants," said Zhang. "For some merchants, the tradeoff works in a way that choosing the smaller daily deal platform can be an effective way to maximize profits."

The authors said that another reason why having a smaller platform in the marketplace is beneficial for merchants is that it provides an alternative outlet for their deals. In the absence of competition from the underdog platform, the larger platform can leverage its bargaining power to negotiate a lower wholesale price, increasing its deal profits. The larger platform passes some of the discount onto the retail price; thus, the platform and consumers gain, at the cost of merchants.

A team of scientists has engineered antiviral compounds that can kill several types of coronaviruses, including SARS-CoV-2, the virus that causes COVID-19. The compounds neutralized viruses in human airway cells and improved survival in mice infected with a deadly, closely related virus that causes Middle East respiratory syndrome (MERS). The new compounds' broad activity suggest that they should be further developed as treatments for infections with emerging coronaviruses, which currently have few effective antivirals and no approved vaccines. Although many coronaviruses cause only mild cases of the common cold, emerging species such as SARS-CoV-2 and SARS-CoV (the cause of the 2003 SARS outbreak) pose a serious risk to global health and security. The spread of SARS-CoV-2 has caused one of the most dangerous pandemics in modern history, and infections with its cousin MERS-CoV have a fatality rate of almost 35%, according to the World Health Organization. In previous work, Athri Rathnayake and colleagues had developed a series of antiviral compounds named 3C-like protease inhibitors, which target an enzyme essential to the replication of coronaviruses. Here, they tested several 3C-like protease inhibitors in cells infected with SARS-CoV-2, SARS-CoV, or MERS-CoV. One of the compounds, named 6e, showed strong activity against SARS-CoV-2 and inhibited viral replication by tenfold in cultured human airway epithelial cells taken from infected donors. Another potent compound named 6j boosted the odds of survival in mice infected with MERS-CoV, slashed the amount of virus in the lungs, and prevented dangerous complications like lung edema. Rathnayake et al. plan to conduct further research to see whether one of their compounds could effectively treat both MERS and COVID-19 in humans.

With these new findings scientists can potentially better understand the subtle changes that can occur in genes and brain circuits that can lead to mental health disorders such as anxiety and autism spectrum disorders.

Although physically very different, research has found that the brains of flies, mice and humans are similar in how they form and how they function. Data has shown that the genetic mechanisms that underlie the brain development of insects and mammals are very similar but this can be interpreted in two different ways, where some believe it provides evidence of one single ancestor for both mammals and insects and others think it could support the theory that brains evolved multiple times independently.

Published in the journal Proceedings of the National Academy of Sciences (PNAS), this collaborative study between King's College London, University of Arizona, University of Leuven and Leibniz Institute DSMZ has provided strong evidence that the mechanisms that regulate genetic activity required for the formation of brain areas important to control behaviour, is the same for insects and mammals.

Most strikingly they have demonstrated that when these regulatory mechanisms are inhibited or impaired in insects and mammals they experience very similar behavioural problems. This indicates that the same building blocks that control the activity of genes are essential to both the formation of brain circuits and the behaviour-related functions they perform. According to the researchers this provides evidence that these mechanisms have been established in one common ancestor.

Senior author on the study, Dr Frank Hirth from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London said: 'To my knowledge this is the first study that provides evidence of the source of similarities between human and fly brains, how they form and how they function. Our research shows that the brain circuits essential for coordinated behaviour are put in place by similar mechanisms in humans, flies and mice. This indicates that the evolution of their very different brains can be traced back to a common ancestral brain more than a half billion years ago.'

Nicholas Strausfeld, Regents Professor of Neuroscience at the University of Arizona and a co-author on the study said: 'The jigsaw puzzle of how the brain evolved still lacks an image on the box, but the pieces currently being added suggest a very early origin of essential circuits that, over an immense span of time have been maintained, albeit with modification, across the great diversity of brains we see today.'

The study focussed on those areas of the brain known as the deutocerebral-tritocerebral boundary (DTB) in flies and the midbrain-hindbrain boundary (MHB) in vertebrates including humans. Using genomic data, researchers identified the genes that play a major role in the formation of the brain circuits that are responsible for basic motion in the DTB in flies and MHB in humans. They then ascertained the parts of the genome that control when and where these genes are expressed, otherwise known as cis-regulatory elements.

The researchers found that these cis-regulatory elements are very similar in flies, mice and humans, indicating that they share the same fundamental genetic mechanism by which these brain areas develop. By manipulating the relevant genomic regions in flies so they no longer regulate the genes appropriately, the researchers showed a subsequent impairment in behaviour. This corresponds to findings from research with people where mutations in gene regulatory sequences or the regulated genes themselves have been associated with behavioural problems including anxiety and autism spectrum disorders.

Dr Hirth commented: 'For many years researchers have been trying to find the mechanistic basis behind behaviour and I would say that we have discovered a crucial part of the jigsaw puzzle by identifying these basic genetic regulatory mechanisms required for midbrain circuit formation and function. If we can understand these very small, very basic building blocks, how they form and function, this will help find answers to what happens when things go wrong at a genetic level to cause these disorders.'

When two neutron stars slam together, the result is sometimes a black hole that swallows all but the gravitational evidence of the collision. However, in a series of simulations, an international team of researchers including a Penn State scientist determined that these typically quiet--at least in terms of radiation we can detect on Earth--collisions can sometimes be far noisier.

"When two incredibly dense collapsed neutron stars combine to form a black hole, strong gravitational waves emerge from the impact," said David Radice, assistant professor of physics and of astronomy and astrophysics at Penn State and a member of the research team. "We can now pick up these waves using detectors like LIGO in the United States and Virgo in Italy. A black hole typically swallows any other radiation that could have come out of the merger that we would be able to detect on Earth, but through our simulations, we found that this may not always be the case."

The research team found that when the masses of the two colliding neutron stars are different enough, the larger companion tears the smaller apart. This causes a slower merger that allows an electromagnetic "bang" to escape. Astronomers should be able to detect this electromagnetic signal, and the simulations provide signatures of these noisy collisions that astronomers could look for from Earth.

The research team, which includes members of the international collaboration CoRe (Computational Relativity), describe their findings in a paper appearing online in the Monthly Notices of the Royal Astronomical Society.

"Recently, LIGO announced the discovery of a merger event in which the two stars have possibly very different masses," said Radice. "The main consequence in this scenario is that we expect this very characteristic electromagnetic counterpart to the gravititational wave signal."

After reporting the first detection of a neutron-star merger in 2017, in 2019, the LIGO team reported the second, which they named GW190425. The result of the 2017 collision was about what astronomers expected, with a total mass of about 2.7 times the mass of our sun and each of the two neutron stars about equal in mass. But GW190425 was much heavier, with a combined mass of around 3.5 solar masses and the ratio of the two participants more unequal--possibly as high as 2 to 1.

"While a 2 to 1 difference in mass may not seem like a large difference, only a small range of masses is possible for neutron stars," said Radice.

Neutron stars can exist only in a narrow range of masses between about 1.2 and 3 times the mass of our sun. Lighter stellar remnants don't collapse to form neutron stars and instead form white dwarfs, while heavier objects collapse directly to form black holes. When the difference between the merging stars gets as large as in GW190425, scientists suspected that the merger could be messier--and louder in electromagnetic radiation. Astronomers had detected no such signal from GW190425's location, but coverage of that area of the sky by conventional telescopes that day wasn't good enough to rule it out.

To understand the phenomenon of unequal neutron stars colliding, and to predict signatures of such collisions that astronomers could look for, the research team ran a series of simulations using Pittsburgh Supercomputing Center's Bridges platform and the San Diego Supercomputer Center's Comet platform--both in the National Science Foundation's XSEDE network of supercomputing centers and computers--and other supercomputers.

The researchers found that as the two simulated neutron stars spiraled in toward each other, the gravity of the larger star tore its partner apart. That meant that the smaller neutron star didn't hit its mbrore massive companion all at once. The initial dump of the smaller star's matter turned the larger into a black hole. But the rest of its matter was too far away for the black hole to capture immediately. Instead, the slower rain of matter into the black hole created a flash of electromagnetic radiation.

The research team hopes that the simulated signature they found can help astronomers using a combination of gravitational-wave detectors and conventional telescopes to detect the paired signals that would herald the breakup of a smaller neutron star merging with a larger.

The simulations required an unusual combination of computing speed, massive amounts of memory, and flexibility in moving data between memory and computation. The team used about 500 computing cores, running for weeks at a time, over about 20 separate instances. The many physical quantities that had to be accounted for in each calculation required about 100 times as much memory as a typical astrophysical simulation.

"There is a lot of uncertainty surrounding the properties of neutron stars," said Radice. "In order to understand them, we have to simulate many possible models to see which ones are compatible with astronomical observations. A single simulation of one model would not tell us much; we need to perform a large number of fairly computationally intensive simulations. We need a combination of high capacity and high capability that only machines like Bridges can offer. This work would not have been possible without access to such national supercomputing resources."

A common green apple vape flavor enhances nicotine reward and is also rewarding itself, according to research in mice recently published in eNeuro.

Vaping entices adolescents into nicotine use with fun flavors like green apple and cotton candy. Nicotine-free flavored vapes have also gained popularity. But of the over 7000 available flavor chemicals, only a handful have been studied. With or without nicotine, flavored vapes pose potential risks for the brain, including addiction.

To continue unravelling these risks, Cooper et al. gave mice either nicotine, the green apple flavorant farnesene, or both in one chamber and a saline solution in another. Farnesene was rewarding by itself, as mice chose the farnesene chamber over the saline chamber. But farnesene also enhanced reward when combined with nicotine.

The research team next measured how farnesene changed nicotine receptor expression and neuron activation. Alone, farnesene partially activated nicotinic receptors, meaning it may increase nicotine's receptor activation when both substances are present. Farnesene also increased the proportion of high- to low-sensitivity receptors. A greater proportion of high-sensitivity receptors increases the effects of a standard nicotine dose, which could heighten reward and drug-seeking behavior. Despite their marketing, vape flavors are not risk-free and may exacerbate the effects of nicotine.

What The Study Did: Changes in emergency department visits and hospitalizations as the COVID-19 pandemic intensified in the U.S. are examined in this observational study that included 24 emergency departments in five health care systems in Colorado, Connecticut, Massachusetts, New York and North Carolina.

Authors: Edward R. Melnick, M.D., M.H.S., of the Yale University School of Medicine in New Haven, Connecticut, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamainternmed.2020.3288)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflicts of interest and financial disclosures, and funding and support.

A large number of the valley networks scarring Mars's surface were carved by water melting beneath glacial ice, not by free-flowing rivers as previously thought, according to new UBC research published today in Nature Geoscience. The findings effectively throw cold water on the dominant "warm and wet ancient Mars" hypothesis, which postulates that rivers, rainfall and oceans once existed on the red planet.

To reach this conclusion, lead author Anna Grau Galofre, former PhD student in the department of earth, ocean and atmospheric sciences, developed and used new techniques to examine thousands of Martian valleys. She and her co-authors also compared the Martian valleys to the subglacial channels in the Canadian Arctic Archipelago and uncovered striking similarities.

"For the last 40 years, since Mars's valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys," says Grau Galofre. "But there are hundreds of valleys on Mars, and they look very different from each other. If you look at Earth from a satellite you see a lot of valleys: some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape. Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them."

The similarity between many Martian valleys and the subglacial channels on Devon Island in the Canadian Arctic motivated the authors to conduct their comparative study. "Devon Island is one of the best analogues we have for Mars here on Earth--it is a cold, dry, polar desert, and the glaciation is largely cold-based," says co-author Gordon Osinski, professor in Western University's department of earth sciences and Institute for Earth and Space Exploration.

In total, the researchers analyzed more than 10,000 Martian valleys, using a novel algorithm to infer their underlying erosion processes. "These results are the first evidence for extensive subglacial erosion driven by channelized meltwater drainage beneath an ancient ice sheet on Mars," says co-author Mark Jellinek, professor in UBC's department of earth, ocean and atmospheric sciences. "The findings demonstrate that only a fraction of valley networks match patterns typical of surface water erosion, which is in marked contrast to the conventional view. Using the geomorphology of Mars' surface to rigorously reconstruct the character and evolution of the planet in a statistically meaningful way is, frankly, revolutionary."

Grau Galofre's theory also helps explain how the valleys would have formed 3.8 billion years ago on a planet that is further away from the sun than Earth, during a time when the sun was less intense. "Climate modelling predicts that Mars' ancient climate was much cooler during the time of valley network formation," says Grau Galofre, currently a SESE Exploration Post-doctoral Fellow at Arizona State University. "We tried to put everything together and bring up a hypothesis that hadn't really been considered: that channels and valleys networks can form under ice sheets, as part of the drainage system that forms naturally under an ice sheet when there's water accumulated at the base."

These environments would also support better survival conditions for possible ancient life on Mars. A sheet of ice would lend more protection and stability of underlying water, as well as providing shelter from solar radiation in the absence of a magnetic field--something Mars once had, but which disappeared billions of years ago.

While Grau Galofre's research was focused on Mars, the analytical tools she developed for this work can be applied to uncover more about the early history of our own planet. Jellinek says he intends to use these new algorithms to analyze and explore erosion features left over from very early Earth history.

"Currently we can reconstruct rigorously the history of global glaciation on Earth going back about a million to five million years," says Jellinek. "Anna's work will enable us to explore the advance and retreat of ice sheets back to at least 35 million years ago--to the beginnings of Antarctica, or earlier--back in time well before the age of our oldest ice cores. These are very elegant analytical tools."

Washington, DC-- New work led by Carnegie's Peng Ni and Anat Shahar uncovers new details about our Solar System's oldest planetary objects, which broke apart in long-ago collisions to form iron-rich meteorites. Their findings reveal that the distinct chemical signatures of these meteorites can be explained by the process of core crystallization in their parent bodies, deepening our understanding of the geochemistry occurring in the Solar System's youth. They are published by Nature Geoscience.

Many of the meteorites that shot through our planet's atmosphere and crashed on its surface were once part of larger objects that broke up at some point in our Solar System's history. The similarity of their chemical compositions tells scientists that they originated as part of common parent bodies, even if they arrived here centuries apart and in vastly different locations.

Deciphering the geologic processes that shaped these parent bodies could teach us more about our Solar System's history and Earth's formative years. To truly understand what makes our planet capable of sustaining life, and to look for habitable worlds elsewhere, it is crucial to understand its interior--past and present.

"Like our Solar System's rocky planets, these planetesimals accreted from the disk of dust and gas that surrounded our Sun in its youth," explained lead author Ni. "And like on Earth, eventually, the densest material sank toward the center, forming distinct layers."

Iron meteorites were thought to be the remnants of the cores of their ancient, broken-apart parent bodies.

"A history of how their layers differentiated is recorded in their chemical makeup, if we can read it," said Shahar.

There are four stable isotopes of iron. (Each element contains a unique number of protons, but its isotopes have varying numbers of neutrons.) This means that each iron isotope has a slightly different mass than the others. As a result, some isotopes are preferred by certain chemical reactions--which, in turn, affects the proportion of that isotope in the reaction's end products.

The traces of this favoritism can be found in rock samples and can help elucidate the processes that forged these meteorite parent bodies.

Previous research on the ratios of iron isotopes in iron meteorites led to a puzzling observation: compared to the raw material from which their parent bodies were constructed, they are enriched in heavy isotopes of iron.

Together with Nancy Chabot and Caillin Ryan of the Johns Hopkins University Applied Physics Laboratory, Ni and Shahar determined that this enrichment can be explained entirely by the crystallization of a parent object's core.

The researchers use lab-based mimicry to simulate the temperatures of core crystallization in iron meteorite parent bodies. Sophisticated models of the crystallization process including other elemental concentrations--for example, of gold and iridium, as well as isotopes of iron--confirmed their findings.

"This improved understanding of core crystallization adds to our knowledge about our Solar System's formative period," Ni concluded.