Culture

Hamilton, ON (August 11, 2020) - Working together, researchers at McMaster University and the University of Waterloo are searching for how the SARS-CoV-2 virus infects the lungs - and they're challenging what has become an accepted truth about the virus.

Previously, scientists have determined that entry of SARS-CoV-2 into cells occurs through a receptor on the cell surface, known as ACE2. But the McMaster-Waterloo team has found that the ACE2 receptor is at very low levels in human lung tissue.

"Our finding is somewhat controversial, as it suggests that there must be other ways, other receptors for the virus, that regulate its infection of the lungs," said Jeremy Hirota, co-lead scientist of the team from the Research Institute of St. Joe's Hamilton and an Assistant Professor of Medicine at McMaster.

"We were surprised that the fundamental characterization of the candidate receptors in human lung tissue had not yet been done in a systematic way with modern technologies."

"Finding such low levels of ACE2 in lung tissue has important implications for how we think about this virus." said co-lead Andrew Doxey, Professor of Biology at the University of Waterloo. "ACE2 is not the full story and may be more relevant in other tissues such as the vascular system."

A paper on their findings has been published recently in the European Respiratory Journal. Their findings have been confirmed independently by other researchers in Molecular Systems Biology.

Now, to explore alternate additional infection pathways and different patient responses to infection, the team is using nasal swabs that were collected for clinical diagnoses of COVID-19. These samples offer the opportunity to determine which genes are expressed by patients' cells and associate this information with the development of the patients' disease.

The ongoing study will better identify and treat patients who are at risk of developing serious complications and provide predictive capacity for hospitals.

"It is clear that some individuals respond better than others to the same SARS-CoV-2 virus. The differential response to the same virus suggests that each individual patient, with their unique characteristics, heavily influences COVID-19 disease severity," said Hirota, who holds the Canada Research Chair in Respiratory Mucosal Immunology at McMaster.

"We think it is the lung immune system that differs between COVID-19 patients, and by understanding which patients' lung immune systems are helpful and which are harmful, we may be able to help physicians pro-actively manage the most at risk-patients."

Researchers will correlate positive and negative COVID-19 cases with clinical outcomes, and ultimately use this data to generate predictive algorithms related to morbidity and mortality. The aim is to use this predictive information to optimize health care delivery.

The research has received grants from the Ontario COVID-19 Rapid Research Fund of the Ontario government, from the COVID-19 Innovation Challenge of Roche Canada and from FastGrants.org managed by the Thistledown Foundation in Canada.

"We're looking for additional partners to collaborate with us in moving this research forward, as we believe there is an opportunity to develop diagnostic devices with this information," said Hirota.

Inbreeding can reduce cooperation in banded mongooses according to a recent study by researchers.

A team from Swansea University, University of Bielefeld and University of Exeter studied inbreeding and cooperative care in banded mongooses - an African mammal which lives in colonies with a complex social structure.

In the 1930s it was proposed that for mammals to evolve complex cooperative societies similar to those seen In bees and wasps, they would have to become highly inbred so that all colony members were genetically related.

This would mean that when they helped other members of their colonies to reproduce, they would be passing down copies of their own genes. However, this kind of society seems to be very rare in nature, and most cooperative mammals go to some effort to avoiding inbreeding.

In banded mongooses that live wild in Uganda, nearly one in 10 pups are the product of brother-sister or father-daughter mating. The team of researchers found that this species may be able to tolerate this high level of inbreeding because the adults in the group provide pups with a lot of one-to-one care that reduces the effects of inbreeding depression.

Inbred pups that get a lot of care in their first three months of life have the same survival chances as outbred pups, while inbred pups that don't receive much care usually die young.

However, in an interesting twist, inbreeding depression eventually catches up with them. The inbred pups that survive because they get a lot of care become bad carers when they are older. This means that the next generation gets a reduced level of care when the adults in the group are inbred.

This may explain why banded mongooses often try not to inbreed, with some individuals risking getting into potentially fatal fights with rival groups in order to breed with unrelated mates.

Dr Hazel Nichols, senior lecturer in biosciences at Swansea University and co-author of the study said: "The complex social lives of banded mongooses never cease to amaze me. They have showed us that, instead of promoting cooperation, inbreeding can, in fact, hinder it."

By José Tadeu Arantes | Agência FAPESP – Arthritis affects almost 2% of the world’s population, or some 150 million people, and currently, there is no completely effective treatment for this chronic disease. A new molecule developed in the laboratory has been shown to have potential therapeutic effects. Tested in mice with genetically induced arthritis, it suppressed the inflammatory process, reducing both inflammation and joint tissue wear and tear. Arthritic mice treated with the substance displayed less pain and swelling and had lower clinical scores measuring the extent of the inflammation than untreated arthritic rats.

The findings are reported in an article in The FASEB Journal, published by the Federation of American Societies for Experimental Biology (FASEB).

“The study showed that this new molecule is capable of controlling the most severe manifestations of the disease,” Marcelo Henrique Napimoga, principal investigator for the project in Brazil, told Agência FAPESP. Napimoga is Head of Graduate Studies, Research and Extension at São Leopoldo Mandic College (SLMANDIC). The study was part of a Thematic Project supported by FAPESP.

The new molecule is called TPPU, short for 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea. Its function of interest is inhibition of soluble epoxide hydrolase (sEH), an enzyme that plays a key role in activating inflammatory processes and can lead to chronic inflammation.

“Our organism naturally produces an anti-inflammatory substance called epoxyeicosatrienoic acid (EET), but sEH converts EET into 1,2-dihydroxyeicosatrienoic acid (DHET), which not only can’t control inflammation but also can have proinflammatory effects. Inhibition of sEH is therefore crucial to the treatment of inflammatory diseases such as rheumatoid arthritis. This is what TPPU does,” Napimoga explained.

The illustration at the top of this page contains two photographs of mouse paws. Both mice have genetically induced arthritis. The one on the left has been treated with TPPU, while the other has not. The treated mouse’s paw is much less swollen and has a lower arthritis score (fewer toes are affected).

According to Napimoga, the treatment also reduced the degree of pain associated with inflammation. “This was because control of the inflammatory process led to a decrease in the migration of white blood cells to the affected region, not just attenuating the disease but reducing cartilage erosion,” he said. “In addition, the treated group showed an increase in the number of regulatory T-cells, lymphocytes that produce anti-inflammatory cytokines, and a decrease in the number of Th17 defense cells, which are highly inflammatory.”

TPPU was designed to be well tolerated and easily absorbed when administered orally. “It boosts the body’s natural defenses and increases the number of metabolites our organism produces. This is a great advantage over conventional treatments based on large doses of corticosteroids, which have adverse side effects,” Napimoga said. “Besides the excellent anti-inflammatory effect, TPPU also has a strong analgesic effect.”

Bruce Hammock, a professor at University of California Davis who developed TPPU and is one of the authors of the FASEB Journal article, was recently awarded a grant of USD 15 million by the National Institute on Drug Abuse (NIDA) to support human clinical trials of a nonopioid pain therapy.

The article “Soluble epoxide hydrolase inhibitor, TPPU, increases regulatory T cells pathway in an arthritis model” can be read at: faseb.onlinelibrary.wiley.com/doi/full/10.1096/fj.202000415R.

Journal

The FASEB Journal

DOI

10.1096/fj.202000415r

Using highly complex analytical techniques, a group of researchers from Charité - Universitätsmedizin Berlin were able to observe in detail how different metals are released from joint implants and accumulate in the surrounding bone tissue. Findings showed a steady release of metals from various implant components. In contrast to previous assumptions, this was not related to the degree of mechanical stress involved. The researchers' findings, which have been published in Advanced Science*, will help to optimize the materials used in implants and enhance their safety.

Modern joint implants restore pain-free mobility of patients with chronic degenerative joint disease, thereby drastically enhancing their quality of life. To ensure long-term mechanical stability, artificial joints are made from materials containing a range of different metal alloys. A crucial factor in determining an implant's long-term effectiveness, however, is its integration into the surrounding bone tissue. Previous studies on implant stability show that friction between the articulating surfaces (bearing surfaces) can result in the formation of metal debris. This wear debris can lead to osteolysis - the destruction of bone around the implant - which can result in premature loosening of the implant. The possibility of a steady release of metal from other parts of the prosthesis had not previously received much attention.

A group of researchers led by Dr. Sven Geißler of Charité's Julius Wolff Institute for Biomechanics and Musculoskeletal Regeneration and BIH Center for Regenerative Therapies has now studied the spatial distribution and local toxicokinetics of metallic wear and corrosion products within the surrounding bone tissue. For their detailed analysis, the researchers used a unique synchrotron-based X-ray fluorescence imaging setup. "Our work has enabled us to show, for the first time, that both particulate and dissolved metals released from arthroplasty implants are present in the surrounding bone and bone marrow at supraphysiological levels," says Dr. Geißler. "Therefore, the collagen-rich layer which encapsulates the implant after surgery does not separate these metals from human tissue to the extent previously assumed."

The researchers collected minute bone and bone marrow samples from 14 patients undergoing either a hip or knee arthroplasty procedure. The researchers then determined the qualitative and quantitative composition of the samples using a technique known a X-ray fluorescence. This technique provides unique insights into the concentration, distribution, location and accumulation of metallic degradation products like cobalt, chromium or titanium in adjacent bone and bone marrow. The extremely bright and intensively focused X-ray beam required was achieved by the synchrotron radiation source at the European Synchrotron Radiation Facility (ESRF). The ESRF, which is located in Grenoble, France, is the only particle accelerator in the world to offer a spatial resolution of up to 30 nanometers. Summing up the researchers' achievements, the study's first author, Dr. Janosch Schoon, says: "Our work therefore addresses an issue of enormous clinical relevance with a highly complex experimental setup."

"Our study has made a major contribution to the improvement of the risk-benefit evaluation of medical devices. It has shown that these evaluations should not only comprise biocompatibility testing of raw materials; rather, biocompatibility testing should also extend to wear and corrosion products. The data from this study will therefore prove instrumental in keeping implant safety at the highest possible level," explains Dr. Geißler. Based on their findings, the researchers plan to conduct additional studies which will investigate the biological consequences of metal release on bones and bone marrow. At the same time, the researchers will develop new approaches which will facilitate the reliable preclinical testing of implant materials using both human cells and engineered tissues.

Research published in DeGruyter's International Journal of Adolescent Medicine and Health suggests TikTok is rich with untapped educational potential. The platform could play a vital role in conveying important health information alongside lip-syncing videos and viral dance challenges, the paper's authors say.

Led by researchers at William Paterson University and Columbia University, the new study, "COVID-19 on TikTok: Harnessing an emerging social media platform to convey important public health messages" explores how coronavirus information is being communicated on the platform. This has been a largely unexplored area - until now.

TikTok is a social media platform on which users share short videos. Since its worldwide release in 2018, it has soared in popularity - especially with teenagers and young people. It now has 800 million users worldwide and 37 billion monthly views in the United States alone.

Using a #Coronavirus hashtag, researchers examined and analyzed 117 TikTok videos, 17 of which were created by the World Health Organization (WHO). Altogether, the videos analyzed in the study received more than a billion views.

Fewer than 10% of the videos mentioned how the virus is transmitted, symptoms of COVID-19 and prevention of viral spread. None of the videos - including those uploaded by the WHO - discussed death and death rates, viral incubation time, wearing a face mask or travel restrictions.

The most commonly portrayed topics were anxiety and quarantine, with little focus on transmission and preventing infection. This may stem from the fact that teenagers are facing many social and emotional challenges as a result of lockdown measures - ranging from coping with school closures to the requirement to minimize contact with others.

The researchers behind the study think this indicates a missed opportunity to engage young people with vital health information related to the global pandemic. TikTok could potentially be used to convey messages about controlling the spread of coronavirus by the strict enforcement of social distancing. It is particularly important to impress this information upon the main TikTok audience of teenagers and young adults who can easily pass on the virus to more vulnerable and older family members.

"It's paramount for public health professionals to tailor messaging in ways that make it most accessible," says the study's lead researcher Dr. Corey Basch. "It's also essential to note that the credibility of TikTok as a source of information is threatened by those whose intentions are to undermine the health and safety of viewers. Identifying the types of barriers to using social media platforms for the benefit of health and safety is a crucial next step," concludes Basch.

In the USA, where the curve of infections has not yet flattened since the beginning of the pandemic, 158,000 people have died from Covid-19 already. And despite the choice by all US states to gradually ease lockdown from late May onwards to save the economy, 14 million Americans have lost their job, while the economic output in the second quarter of 2020 dropped by 9.5%. To help entrepreneurs decide on how they can safely reopen their business, mathematicians and statisticians here develop a model for the spread of infections within companies and the economic payoff of safety measures. Their findings are published today in Frontiers in Applied Mathematics and Statistics.

"Our aim was to provide a quantitative yet simple modeling tool for business executives to plan for reopening their workplace," says lead author Prof Hongyu Miao, Director of the Center for Biostatistics Collaboration and Data Services at the University of Texas Health Science Center in Houston, Texas.

The authors show mathematically that, under a wide range of parameters, reopening your business will only be feasible if at least these safety measures are adopted: wearing goggles, gloves, and masks (when employees aren't alone); frequent hand washing; routine sanitation of the workfloor; social distancing; monitoring body temperature; and quarantine of exposed and sick employees. These measures won't only control the spread of Covid-19 within the company, but also increase your net profit under the assumptions of the model.

"We show that a business entity may stand a good opportunity to generate positive net profit after reopening only if necessary protection measures are strictly implemented," warns Miao. "It is also very important to monitor the number of infections through virus testing and contact tracing, especially at the early stage of reopening."

About the model

Miao and colleagues first developed - and (approximately) solved numerically - five differential equations for the numbers of susceptible, infectious, quarantined, deceased, and recovered employees within a company. These assumed that all workers who can work from home do so, and that workers self-quarantine as soon as they present symptoms, or if they have been in close contact with a known carrier. They further assumed that infected employees who aren't detected - because they are asymptomatic or only mildly symptomatic cases, in the early stages of the disease, or apparently recovered but still infectious - can continue to infect their susceptible coworkers as "silent spreaders", and that sick and quarantined workers receive their full pay.

In addition, the authors modeled the net profit, based on the average salary and productivity of US workers, the cost of PPE and other safety measures, and the reduction in productivity expected from a limit on working hours and the need for distancing. They estimated values for key parameters from the literature, for example the effectiveness of PPE in preventing transmission, the expected pricetag of these measures, and the dynamics of infection.

Four scenarios compared

The authors then took a large, well-known Texan company as a hypothetical example. Under the least safe scenario, where no safety measures are taken, the prevalence of Covid-19 within the company steadily rises to become 30-fold higher than in the general US population, indicating that reopening won't be feasible. Under the safest scenario, where all possible safety measures are adopted, its prevalence falls to 104-fold lower than in the population, resulting in a higher and more stable net profit. Results are similar under the second-safest scenario, where only the most expensive measures are omitted - non-contact sensors for real-time fever detection, reducing working hours by 30% to limit exposure, and UV purification or High-Efficiency Particulate Air (HEPA) filters that prevent viral transmission in aerosols. Finally, under the third-safest scenario, where employees further drop the use of PPE, the workplace again quickly becomes a "hot spot" of infection, resulting in a lower net profit.

UBC researchers are raising the alarm about the increase of vaping among teenagers and how e-cigarette marketing strategies target youth.

Assistant Professor Laura Struik, who teaches in UBC Okanagan's School of Nursing, recently published a paper examining why teens take up vaping and whether advertising capitalizes on those reasons.

"This is the first study of its kind that makes direct links between reasons for youth uptake and the marketing strategies of e-cigarette companies," says Struik. "The public needs to know how the next generation is being targeted to take up and ultimately become addicted to these nicotine products."

Struik conducted the study with Assistant Professor Sarah Dow-Fleisner, who conducts research in the UBCO School of Social Work on development trajectories and resilient functioning of children and families in high-risk contexts.

The researchers say there are a variety of reasons teens take up vaping--ranging anywhere from managing stress or anxiety, curiosity, taste, peer pressure, easy access and even factors like it's easy to hide from parents and is perceived to be less harmful than cigarettes.

When e-cigarettes first entered the North American market in 2008, they were hailed as a smoking cessation tool. However, Dow-Fleisner says when they take a closer look at who uses them, it's clear teens do not use the products to quit smoking.

"According to recent statistics, only three per cent of Canadian youth in grades 7 to 12 are current smokers--while 20 per cent use e-cigarettes," she says. "This suggests that upwards of 17 per cent of e-cigarette users were originally non-smokers. In addition, among youth who do smoke combustible cigarettes, fewer than eight per cent of those report using e-cigarettes to quit smoking."

Recent polls found that 95 per cent of teens said they were curious about vaping so they wanted to try it, while 81 per cent tried an e-cigarette because a friend vaped, and 80 per cent reported continued e-cigarette use because they enjoyed the good flavours. More than 70 per cent of the teens agreed e-cigarettes were "cool and fun."

Despite emerging evidence of both short- and long-term health risks associated with vaping, Struik says the evidence is clear the other reasons teens take up vaping override the health risks.

"Youth don't make the decision to vape because they don't understand the risks or don't care about the risks," she says. "Young people are taking up vaping for a variety of reasons and e-cigarette companies are leveraging those diverse reasons to recruit teens into using their products. And it's working."

Struik and Dow-Fleisner, with their research assistants and UBCO's Associate Chief Librarian Robert Janke, reviewed more than 800 studies and viewed numerous e-cigarettes TV commercials.

"The TV advertisements we reviewed were found to tap into almost all of the reasons youth cite for taking up e-cigarettes," says Dow-Fleisner. "The most highly-cited reasons were most prominently presented in the ads, including a focus on relational aspects of vaping and product-related benefits, such as a positive sensory experience."

A noteworthy finding is that vaping advertisements do promote e-cigarettes as a way to enhance your social life, says Struik.

"This is particularly concerning because teens are at a developmental stage when establishing a social identity is of utmost importance to them," she says. "It has been found in previous research that forming an identity around other forms of tobacco use, like smoking, results in resistance to health promotion efforts. So, we may have a more challenging context to work with than originally thought when it comes to intervening."

Youth vaping is a concern, she adds, and there is a growing need for comprehensive strategic plans to curtail their use of e-cigarettes.

"It is clear that we need to bring youth to the table to understand how we can generate relevant information and interventions to support their decision to not vape," says Struik. "Our health promotion efforts need to keep up by accommodating the various reasons youth report vaping, and youth need to be meaningfully included to navigate this issue."

BINGHAMTON, NY -- With schools around the world looking into various cost-cutting measures in the midst of the COVID-10 pandemic, new research from Binghamton University, State University of New York reveals that citizens prefer teachers and administrative staff to be at the frontline of school spending cuts during times of economic crisis.

Komla Dzigbede, assistant professor of public administration at Binghamton University, examined public attitudes toward school budget cuts during the Great Recession (2008-2009), a time when many state governments cut back on public education spending and school districts responded with different cost-cutting strategies to ease budget stress while maintaining educational goals.

"During times of major economic crises, school districts must make critical cost-cutting decisions, even as they face constraints on raising additional revenues," said Dzigbede. "As school districts weigh alternate cost-cutting strategies in times of crises -- whether to cut spending on salaries, instruction or support services -- citizens, in turn, worry about the impacts school budget cuts would have on educational quality in the local community. How does the public perceive the impact of different forms of school spending cuts on educational quality during times of major economic crises? What factors influence those perceptions? And what insights can school district managers and education policymakers gain from citizens' perceptions to inform critical decision-making in times of major crises?"

Dzigbede's findings indicate that during times of serious crises, citizens tend to view canceling after-school activities and reducing funds for instructional materials as having more harmful impacts on educational quality than cutting teachers' pay, cutting teachers' training or cutting administrative staff positions.

Additionally, Dzigbede found that gender, age, income, party identification and political ideology are significant determinants of public attitudes toward different forms of school spending cuts. Women, younger people, lower-income earners and less-conservative people differ from other demographics in their attitudes toward different cost-cutting strategies.

These research findings offer practical insights for school district administration, management, and policy, said Dzigbede.

"When making critical decisions about cost-cutting strategies in times of major crises, school district managers and education policymakers need to know the socio-demographic, economic and ideological preferences of citizens and take these into account in managerial decision making to promote responsive, participatory and accountable governance," said Dzigbede.

BOSTON (August 10, 2020, 9:00 a.m. EDT)--Whole grain labels on cereal, bread, and crackers are confusing to consumers and could cause them to make fewer healthy choices, according to the results of a study that tested whether people are able pick out the healthier, whole grain option based on food package labels.

The study, led by researchers at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University and NYU School of Global Public Health, is published today in Public Health Nutrition. The researchers say the findings could help lead to enhancements in food labeling.

A pool of 1,030 U.S. adults, representative of the population, responded to a survey with photos of both hypothetical and real products. The photos showed the products, with various whole grain labels on the front of the package, along with the nutrition facts label and ingredients list for each product. Participants were asked to identify the healthier option (for the hypothetical products) or assess the whole grain content (for the real products).

* For the hypothetical products, 29-47% of respondents answered incorrectly (specifically, 31% incorrectly for cereal, 29-37% for crackers, 47% for bread).

* For real products that were not mostly composed of whole grains, 43-51% of respondents overstated the whole grain content (specifically, 41% overstated for multigrain crackers, 43% for honey wheat bread, and 51% for 12-grain bread). Consumers more accurately stated the whole grain content for an oat cereal product that really was mostly composed of whole grain.

"Our study results show that many consumers cannot correctly identify the amount of whole grains or select a healthier whole grain product. Manufacturers have many ways to persuade you that a product has whole grain even if it doesn't. They can tell you it's multigrain or they can color it brown, but those signals do not really indicate the whole grain content," said first author Parke Wilde, a food economist and professor at the Friedman School.

The packages on the hypothetical products either had no front-of-package whole grain label or were marked with "multigrain," "made with whole grains," or a whole grain stamp. The packages on the real products displayed the actual product markings, including "multigrain," "honey wheat," and "12 grain."

The study goal was to assess whether consumer misunderstanding of the labels meets a legal standard for enhanced U.S. labeling requirements for whole grain products. The legal standard relates to deceptive advertising, and evidence that the labels are actually misleading--or likely to mislead--consumers can bolster support for regulations.

"With the results of this study, we have a strong legal argument that whole grain labels are misleading in fact. I would say when it comes to deceptive labels, 'whole grain' claims are among the worst. Even people with advanced degrees cannot figure out how much whole grain is in these products," said co-author Jennifer L. Pomeranz, assistant professor of public health policy and management at NYU School of Global Public Health.

Previous research has shown disparities in whole grain intake in the United States, including for example, lower intake for adolescents than for adults, and lower intake for participants in the Supplemental Nutrition Assistance Program (SNAP) than for higher-income non-participants. The authors of the new study found that consumers who were younger, had less education, were Black or African American, or reported having difficulty understanding food labels were more likely to answer incorrectly in the test involving hypothetical products.

The2015-2020 Dietary Guidelines for Americans recommend that half of all grains consumed should be whole grains. Adequate intake of whole grains has been linked with reduced risk of heart disease, type 2 diabetes, and cancer.

"A large chunk of Americans' daily calories - 42 percent - comes from low quality carbohydrates. Consuming more whole grains can help change that, but the policy challenge is to provide consumers with clear labels in order to make those healthier choices," said co-senior author Fang Fang Zhang, nutrition epidemiologist at the Friedman School.

Limitations of the study include the fact that higher education respondents were moderately over-represented, which means the results are conservative. Also, a formal response rate to the survey cannot be calculated because participants were part of ongoing survey panels and volunteered to respond.

Whether you are playing Go in a park amid chirping birds, a gentle breeze and kids playing catch nearby or you are playing in a den with a ticking clock on a bookcase and a purring cat on the sofa, if the game situation is identical and clear, your next move likely would be, too, regardless of those different conditions. You'll still play the same next move despite a wide range of internal feelings or even if a few neurons here and there are just being a little erratic. How does the brain overcome unpredictable and varying disturbances to produce reliable and stable computations? A new study by MIT neuroscientists provides a mathematical model showing how such stability inherently arises from several known biological mechanisms.

More fundamental than the willful exertion of cognitive control over attention, the model the team developed describes an inclination toward robust stability that is built in to neural circuits by virtue of the connections, or "synapses" that neurons make with each other. The equations they derived and published in PLOS Computational Biology show that networks of neurons involved in the same computation will repeatedly converge toward the same patterns of electrical activity, or "firing rates," even if they are sometimes arbitrarily perturbed by the natural noisiness of individual neurons or arbitrary sensory stimuli the world can produce.

"How does the brain make sense of this highly dynamic, non-linear nature of neural activity?" said co-senior author Earl Miller, Picower Professor of Neuroscience in The Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences (BCS) at MIT. "The brain is noisy, there are different starting conditions - how does the brain achieve a stable representation of information in the face of all these factors that can knock it around?"

To find out, Miller's lab, which studies how neural networks represent information, joined forces with BCS colleague and mechanical engineering Professor Jean-Jacques Slotine, who leads the Nonlinear Systems Laboratory at MIT. Slotine brought the mathematical method of "contraction analysis," a concept developed in control theory, to the problem along with tools his lab developed to apply the method. Contracting networks exhibit the property of trajectories that start from disparate points ultimately converging into one trajectory, like tributaries in a watershed. They do so even when the inputs vary with time. They are robust to noise and disturbance, and they allow for many other contracting networks to be combined together without a loss of overall stability - much like brain typically integrates information from many specialized regions.

"In a system like the brain where you have [hundreds of billions] of connections the questions of what will preserve stability and what kinds of constraints that imposes on the system's architecture become very important," Slotine said.

Math reflects natural mechanisms

Leo Kozachkov, a graduate student in both Miller's and Slotine's labs, led the study by applying contraction analysis to the problem of the stability of computations in the brain. What he found is that the variables and terms in the resulting equations that enforce stability directly mirror properties and processes of synapses: inhibitory circuit connections can get stronger, excitatory circuit connections can get weaker, both kinds of connections are typically tightly balanced relative to each other, and neurons make far fewer connections than they could (each neuron, on average, could make roughly 10 million more connections than it does).

"These are all things that neuroscientists have found, but they haven't linked them to this stability property," Kozachkov said. "In a sense, we're synthesizing some disparate findings in the field to explain this common phenomenon."

The new study, which also involved Miller lab postdoc Mikael Lundqvist, was hardly the first to grapple with stability in the brain, but the authors argue it has produced a more advanced model by accounting for the dynamics of synapses and by allowing for wide variations in starting conditions. It also offers mathematical proofs of stability, Kozachkov added.

Though focused on the factors that ensure stability, the authors noted, their model does not go so far as to doom the brain to inflexibility or determinism. The brain's ability to change - to learn and remember - is just as fundamental to its function as its ability to consistently reason and formulate stable behaviors.

"We're not asking how the brain changes," Miller said. "We're asking how the brain keeps from changing too much."

Still, the team plans to keep iterating on the model, for instance by encompassing a richer accounting for how neurons produce individual spikes of electrical activity, not just rates of that activity.

They are also working to compare the model's predictions with data from experiments in which animals repeatedly performed tasks in which they needed to perform the same neural computations, despite experiencing inevitable internal neural noise and at least small sensory input differences.

Finally, the team is considering how the models may inform understanding of different disease states of the brain. Aberrations in the delicate balance of excitatory and inhibitory neural activity in the brain is considered crucial in epilepsy, Kozachkov notes. A symptom of Parkinson's disease, as well, entails a neurally-rooted loss of motor stability. Miller adds that some patients with autism spectrum disorders struggle to stably repeat actions (e.g. brushing teeth) when external conditions vary (e.g. brushing in a different room).

Secondary school students perform better in natural sciences and mathematics and are more motivated when digital tools are used in instruction. However, success depends on the design of the tools used. Success levels are higher when children and young adults do not study alone and when digital instruction is accompanied by paper-based teaching materials, according to the conclusion reached by one of the largest investigations on the topic, evaluating approximately 90 individual studies.

Digitalization of school instruction has been hotly debated for years. What programs should teachers use on the computer, when and how often? The debate is characterized by a challenging abundance of research projects. The Center for International Student Assessment (ZIB) at the Technical University of Munich (TUM) has now evaluated a total of 92 studies published worldwide since the year 2000.

The meta-study shows that secondary school students in classes which work with digital teaching tools perform better than children and young adults in classes that are taught solely on a traditional basis. Furthermore these students are more motivated by the respective subject. This applies for all grades in secondary schools and for all the subjects investigated, i.e. mathematics, biology, chemistry and physics.

However, digital tools alone are no guarantee of success. Their impact on performance depends on how they are used in instruction:

Children and young adults benefit more from digital teaching tools when they work together in pairs instead of alone. The researchers assume that computer programs play a special role in stimulating discussions between the students which can positively impact the learning process.

Secondary school students perform better when accompanied by teachers while working with digital tools. When they work with computer programs entirely alone, the positive effect is minor.

The positive effect of digital tools is greater when the tools do not completely replace classic classroom materials. A promising approach is to use them in supplement to analog methods.

Digital tools increase performance more particularly when teachers have been professionally trained how to integrate them into the lessons.

Not even well-made programs can replace teachers

"Digital tools should be worked into instruction in moderation," says Prof. Kristina Reiss, head of the ZIB and dean of the TUM School of Education. "Getting rid of tried and proven analog formats would be going a step too far. In addition, we see that even very well-made learning programs cannot replace the teacher."

In well-planned application, the advantages of digital tools could be completely leveraged, in particular for complex and abstract content in natural sciences and mathematics, for example the visualization of chemical compounds and geometric shapes.

"If the new teaching methods can additionally increase the motivation of secondary school students, this will be a great opportunity for the STEM subjects," Reiss points out.

Some digital tools are more useful than others

The meta-study also indicates which types of digital tools are most promising. The greatest positive effect comes from what are referred to as intelligent tutor systems, programs which convey content in small units and also enable individual exercises. The decisive factor is that these programs adapt the speed, level of difficulty and amount of assistance to the user's skills. On the other hand, hypermedia systems configured for free exploration with video, audio and text materials that fail to define a learning objective are comparatively less effective.

PULLMAN, Wash. - Automatic gratuities leave restaurant patrons with a bad taste, even when the meal and the service were excellent, new research from Washington State University indicates.

"We thought if service quality was high, people wouldn't care if an automatic service charge was added to their bill," said Jeff Joireman, the study's coauthor and professor and chair of the Department of Marketing and International Business at the Carson College of Business.

But whether customers had a good experience or bad one, they reacted negatively when their bill came with a mandatory tip, preventing them from leaving the gratuity themselves. Surprisingly, customers with the best dining experiences expressed the most dissatisfaction with automatic gratuities. The research was published in Journal of Services Marketing and was based on four separate studies.

"People think non-voluntary tipping systems are unpopular because customers can't punish servers for poor quality service," Joireman said. But when the service was high, "we found that customers were equally frustrated by non-voluntary tipping - this time because they couldn't reward their servers."

In both service scenarios, customers said they were unlikely to patronize the restaurant in the future.

Non-voluntary tipping systems take control away from the customer, said Ismail Karabas, assistant professor of marketing at Murray State University and lead author of the research, which was part of his doctoral dissertation at WSU.

"Being able to reward the server makes customers feel good," Karabas said. "That's part of the restaurant experience."

When customers lose control of the tip, "their ability to show their gratitude has been blocked," he said. "They have fewer positive feelings about the restaurant experience, and they're less likely to eat there again."

Automatic gratuities growing in restaurant industry

North American customers spend about $66 billion annually on tips at restaurants and other establishments. Although voluntary tipping is still standard practice, a growing number of restaurants are moving toward automatic gratuities, Karabas said.

For restaurant owners, the switch to automatic gratuities is often about fairness, he said. They want to divide tips between servers and the kitchen staff, rewarding the entire team and equalizing pay.

"The person who cooks your meal may be working harder than the server, but servers end up making quite a bit more money when you add in the tips," Karabas said. "That's led to turnover of kitchen staff, which is a concern in the restaurant industry."

While the intent of using automatic gratuities to equalize pay and retain employees is laudable, restaurant owners and managers should be aware of the drawbacks, he said.

"High-quality service does not compensate for the negative customer response to a non-voluntary tipping system," Karabas said. "Managers may think 'We're fine as long as we provide good service,' but we found that's just not true."

Exploring other ways to reward good service

Restaurants thatswitch to automatic tipping could explore other ways to help customers keep their sense of control, the researchers said.

"Based on what we know about blocked gratitude, I would look for ways to give customers the feeling they are still the ones leaving the tip, even though it's added automatically," Karabas said. "It could be as simple as saying, 'You tipped your server 18% today. Thank you.'"

Restaurants could also encourage customers to reward their servers through other means, such as providing feedback on comment cards, voting for a server of the month, or even adding a separate line on the bill for an extra tip, the researchers said.

But restaurants should be careful about perceptions, according to Karabas, who said additional research is needed on alternate ways to reward servers. Some customers might react cynically to an extra line on their bill for an enhanced tip.

"You don't want customers to think you're being sneaky and trying to trick them into tipping twice," he said.

Scientists are closer to gaining the upper hand on a disease that has wiped out citrus orchards across the globe. New models of the bacterium linked to the disease reveal control methods that were previously unavailable.

Metabolic models of organisms are like road maps of cities.

"They show you all the biological processes, and how they work together," said UC Riverside microbiology professor James Borneman. "They also show you which molecular pathways, if blocked, will kill the organism."

In this case, researchers created the first models of the bacterium associated with Huanglongbing or HLB, also known as citrus greening disease. The team's work is described in a new paper published in Nature's npj Systems Biology and Applications.

The research team made models for six different strains of the bacterium known as CLas and doing so enabled them to identify as many as 94 enzymes essential for the bacterium's survival. These enzymes can now be considered targets for the creation of new antibacterial treatments.

In addition, the team identified metabolites required for the bacteria to grow.

"Just like when humans break down the food they eat into small components called metabolites, which feed our cells, bacterial cells also require metabolites for their growth," Borneman said.

Knowing the metabolites needed for CLas' growth could enable scientists to cultivate it in a laboratory setting. It is not currently possible to grow CLas on its own, hindering scientists' ability to study it and ultimately to manage it.

This research project involved a collaboration between UC Riverside, UC San Diego, Texas A&M University, and the U.S. Department of Agriculture. In addition to Borneman, members of the modeling team included UCR plant pathologist Georgios Vidalakis and UCSD systems biologist Karsten Zengler.

UC Riverside is at the forefront of efforts to combat Huanglongbing. Other important areas of research include antibacterial development and delivery, immune system fortification in citrus, engineering resistant citrus via a detailed understanding of host-microbe interactions, breeding resistant citrus, and insect management, among others.

Because microbes tend to mutate and acquire resistance mechanisms in response to drugs and other efforts to thwart them, Borneman cautions that any one solution to the problem may be short-lived.

"Microbes almost always adapt to control measures, perpetuating the 'arms race' between pathogens and hosts," Borneman said. "There won't be one thing that will fix this disease. We likely will need to address all three components associated with the disease -- the bacterium, the insect that transmits it, and the citrus plants -- to find a long-lasting solution."

To that end, the research team is constructing metabolic models of citrus and the insect, the Asian citrus psyllid.

"We expect that this multiorganism modeling endeavor will provide new insights into the mechanisms underlying this disease, which will lead to effective and sustainable Huanglongbing management strategies," Borneman said.

Modelling the predicted movements of pervasive sap-sucking tiny insects before they infest banana crops has the potential to become a key tactic in the fight against a devastating virus, according to QUT research.

Banana bunchy top virus (BBTV) is an aphid-transmitted banana disease that has been in Australia since 1913 and has been contained by biosecurity agencies to southeast Queensland and northern New South Wales.

Badly affected plants will not produce fruit if left unchecked and entire plantations can become infested.

BBTV cannot be cured and infected plants must be destroyed.

QUT researchers have designed a model that tracked the probability of a banana plant being infected by aphids that carried the disease, with the findings published in PLOS Computational Biology.

Keypoints:-

Aphids can fly long distances to new plantations and quickly infect nearby plants.

Current inspection measures by biosecurity agents are costly and time-consuming.

Mathematical and statistical models can help to predict areas of risk of infection.

A stochastic mathematical model describes disease spread, infectivity and recovery rates.

External environmental and seasonal factors influence virus spread.

The framework can be adapted to study dynamics of other vector-borne diseases.

A 2012 study estimated the benefits from eliminating the disease would be worth between $16-27 million to Australia each year.

Distinguished Professor Kerrie Mengersen said despite ongoing traditional methods of monitoring and management of the disease, eradication had proved elusive.

The latest study, conducted in collaboration with biosecurity agents, focused on a BBTV-infected banana plantation in northern New South Wales.

The location of every diseased plant in the plantation was recorded using GPS.

Associate Professor Chris Drovandi said the research expanded existing disease management strategies by calibrating the model to real field data.

"The new model we've developed quantifies the effects of seasonal changes, the plantation's configuration and spread of banana bunchy top virus while predicting high-risk areas," Associate Professor Drovandi said.

"Peak transmission occurs when temperatures reach 25-30 degrees, so weather is an important factor to consider in the complex dynamics of BBTV spread."

Since 2014, the banana farm has undergone monthly inspections implementing a "rogue-and-remove" disease management strategy.

QUT researcher Abhishek Varghese joined the study as part of an undergraduate vacation research scholarship, visiting the farm and meeting industry officials.

He said it was difficult to see the symptoms of virus on plants from the air, or by using drones, as the leaves needed to be viewed underneath for infestations.

"The banana trees grow along a steep slope and insects can be swept up and pushed to different parts of the plantation by seasonal forces," he said.

"Since the 1930s field surveyors have scoured the plantation attempting to individually identify infections by checking banana leaves showing a choked or bunched appearance.

"They mark the infected area without interrupting the insects and spray paraffin oil to ensure the aphids can't escape and inject a systemic insecticide and herbicide (glyphosate) slowly killing the banana plant and all the aphids inside it."

Mr Varghese, who is studying a dual engineering and economics degree at QUT, said stochastic mathematical modelling also helped pinpoint areas where the disease remained latent in the soil two or three months after trees had been removed.

"This is an expensive and laborious process for field surveyors so a precise forecasting tool may assist in pinpointing areas to inspect more carefully, reducing costs and making the job easier," he said.

BBTV was first introduced to Australia in 1913 via infected suckers from Fiji and spread locally through the banana aphid, Pentalonia nigronervosa.

"This is a fantastic example of talented students using mathematical and statistical skills to help solve real problems facing farmers and the agriculture industry," Professor Mengersen said.

Researchers from University of Missouri-Kansas City, University of Wisconsin-Milwaukee, and University of Pennsylvania published a new paper in the Journal of Marketing that examines the effectiveness of what they call "the dueling preferences approach" on prosocial giving.

The study, forthcoming in the Journal of Marketing, is titled "Penny for Your Preferences: Leveraging Self-Expression to Encourage Small Prosocial Gifts" and is authored by Jacqueline Rifkin, Katherine Du, and Jonah Berger.

BallotBin, a UK-based company, designs custom bins for the disposal of cigarette butts. These "ballot bins" have a fascinating feature: They pose a question and provide two bin compartments, each labeled with a possible answer to the question. Smokers can then answer the question through the disposal of a cigarette butt into either compartment. For example, one recent "ballot bin" in London asked smokers whether flying or invisibility is the better superpower, allowing them to express their preference by depositing their cigarette butts in one of two labeled compartments. This set-up can be found in a variety of other settings designed to increase prosocial acts. Cafés have started to position two tip jars rather than one, asking patrons whether they prefer Star Trek or Star Wars. Similarly, the ASPCA asked people to donate money by expressing their preference for cats or dogs ("Vote for your Paw-sident").

This set-up, in which the act of giving is framed as a choice between two options, is called the "dueling preferences" approach. But the question remains: Is the dueling preference approach really more effective at increasing prosocial giving than traditional approaches? And if so, why?

The research team set out to answer these questions. They conducted initial experiments in real cafés and with real charities using several different "duels" (summer vs. winter, mountains vs. beach, chocolate vs. vanilla ice cream) and discovered that the dueling preferences approach can indeed be more effective than traditional approaches at increasing small prosocial gifts. In particular, the dueling preferences approach increased people's likelihood to tip/donate and how much money they gave.

Next, the researchers sought to understand why this approach works. Several follow-up studies indicate this approach works because it provides people with the opportunity to say something about who they are. Du explains, "People love to talk about themselves and share their opinions. In fact, the parts of the brain that light up when we get to share our opinions also light up in response to finding $10 or getting a sweet treat. This fact about human psychology ultimately makes the dueling preferences approach an inherently attractive and motivating opportunity. People are willing to give money to share what they believe in."

Of course, the dueling preferences approach must be implemented tactfully. People may be willing to give money to share what they believe in, but what if a duel captures an issue people don't believe in? As Rifkin described, "When we tested a duel that asked people's preferences for the letter "A" vs. "B"--a relatively uninspiring issue--we were not able to increase prosocial giving. Similarly, when we tested a duel that was interesting to some, but not to all--one's preference for pets--we found that the duel only increased giving among those who found the issue to be important to them. Also, people do not always want or even need to express themselves." While the inherent need to say something about who we are is critical for harnessing the power of dueling preferences, people differ in what and when they want to share. As a result, it takes some thought to figure out exactly what options to choose, when, and among whom to deploy this approach.

Overall, those interested in increasing prosocial giving can benefit by leveraging the flexibility and ease of implementation of the dueling preferences approach. Ultimately, if managers can effectively harness people's desire to express themselves, this approach can be a powerful tool for increasing prosocial giving. The magic of dueling preferences lies in its ability to leverage any valued identity--whether a Star Trek fan, chocaholic, or lefty--to increase prosocial giving.