Culture

WASHINGTON, April 2, 2020 -- Cold brew may be the hottest trend in coffee-making, but not a lot is known about how this process alters the drink's chemical characteristics. Scientists now report that the content of potentially health-promoting antioxidants in coffee brewed without heat can significantly differ from a cup of joe prepared with the same beans in the traditional way, particularly for dark roasts.

The researchers are presenting their results through the American Chemical Society (ACS) SciMeetings online platform.

A brand-new video on the research is available at http://www.acs.org/philly-2020-coffee.

"This study can inform coffee enthusiasts about how they may want to craft their own coffee at home, based on science and on analytical chemistry," says Meghan Grim, an undergraduate student who worked on the project.

"After I first tried cold-brew coffee, I wanted to make it at home, but it didn't turn out too great," says Niny Z. Rao, Ph.D., the project's principal investigator. With her collaborator, Megan Fuller, Ph.D., Rao looked into the scientific literature to learn what she had done wrong. "It turns out there weren't any studies on cold-brew coffee at the time," Rao says, "so we decided to do some."

In the cold-brew process, ground coffee is mixed with room-temperature or colder water and steeped for as long as two days, sometimes in a refrigerator. It can be drunk cold or hot. In hot brewing, ground coffee is mixed with boiling or near-boiling water and steeped at most for a few minutes. In either case, the coffee grounds are sometimes pressed, and the beverage is then filtered to remove the grounds.

The researchers, who are at Thomas Jefferson University, previously assessed acidity and antioxidants in hot- and cold-brew java from lightly roasted beans. In another project, they analyzed the effect of medium and dark roasting, and of medium and coarse grinding, on a few coffee attributes. Now they're taking a deeper dive by roasting Columbian beans at five different temperatures -- from light roasting at 174 C to dark roasting at 209 C -- and studying the impact on acidity, antioxidants and other natural chemicals in hot- and cold-brew coffee.

With the lighter roasts, Rao's team finds that the content of caffeine and antioxidants is pretty similar in hot and cold brews. However, significant differences show up with the darker roasts. "Hot brewing extracts more antioxidants from the grind than cold brew, and this difference increases with the degree of roasting," Rao says. So hot-brew of dark roasts produces a potentially healthier drink. Hot brew also contains more of certain kinds of acids and total dissolved solids. The pH is about the same for both hot and cold brews at equivalent roast, though both become less acidic as roasting temperature increases.

"My advice to consumers has always been to drink what they like," Rao says. "But if you want to craft a coffee beverage with antioxidants or acidity in mind, you may want to pay attention to roast. If you want a low-acid drink, you may want to use a darker roast. But remember that the gap between the antioxidant content of hot- and cold-brew coffee is much larger for a darker roast."

One of the biggest challenges in all these projects is reproducibility. "We have performed experiments in which we're using the same beans, the same machine, the same settings, and it comes out not quite the same as the previous batch," Rao says. "The same goes for brewing. To create a cup that's consistent every time is really difficult. I have a lot of respect for the baristas who can do that." To approach that level of perfection, the researchers became like drill sergeants, carefully standardizing their processes. They developed a procedure for when the water should be added to the ground coffee, how to pour the water and for how long, how to shake the solution, how to press the brewed coffee and how to analyze it. They set time limits for each step, with margins of just a few seconds. This rigor produced much more reproducible results.

The team has now begun comparing the impact of the two brewing processes and degree of roast on furans, flavor compounds present in raw coffee beans that are also generated through roasting. Such compounds are particularly important in cold-brew joe, which doesn't have the same distinct aroma as the hot drink because it lacks steam to carry volatile organic compounds to the nose.

A new study in Nature Communications proposes a method to extend polygenic scores, the estimate of genetic risk factors and a cornerstone of the personalized medicine revolution, to individuals with multiple ancestral origins. The study was led by Dr. Davide Marnetto from the Institute of Genomics of the University of Tartu, Estonia and coordinated by Dr. Luca Pagani from the same institution and from the University of Padova, Italy.

"The information contained in our DNA is a mosaic of genetic instructions inherited from our ancestors, and in many societies one's ancestors often come from the opposite corners of the world." says Dr. Davide Marnetto, first author of the study. The contribution of one's ancestry, or ancestries, to the total risk of developing a specific disease or presenting a given trait is a long standing question of medical genomics. Nevertheless, most of the genotype/phenotype association data come from relatively uniform populations, in order to have a simplified and clearer picture. But what can be done when dealing with individuals who derive their ancestry from two or more distantly related populations?

"The latest developments of personalized medicine needed an extra step to be applied to individuals with more diverse origins, and here we tried to combine knowledge from homogeneous populations into a model that could work for recently admixed individuals" continues Dr. Marnetto.

To separate the various genomic components of each individual, Marnetto and colleagues applied methods from molecular anthropology and population genomics. "This research is a welcomed example of deep synergy between evolutionary/population genetics framework and medically oriented large scale genomics science, which is one of the focuses of our institute." says Dr. Mait Metspalu who is heading the institute of Genomics at the University of Tartu.

"Our work provides a solid proof of principle on the feasibility of using population genetic and molecular anthropology to boost the potential of personalized medicine. I hope our work can bring individuals of mixed ancestry one step closer to the benefits of personalized and predictive healthcare" concludes Dr. Luca Pagani, the research coordinator.

A newly developed wireless biologging network (WBN) enables high-resolution tracking of small animals, according to a study published April 2 in the open-access journal PLOS Biology by Simon Ripperger of the Leibniz Institute for Evolution and Biodiversity Science, and colleagues. As noted by the authors, WBNs could close an important gap in biologging: the fully automated tracking and proximity-sensing of small animals, even in closed habitats, at high spatial and temporal resolution.

Recent advances in animal tracking technology have ushered in a new era in biologging. By collecting data of unprecedented quantity and quality, automated methods have revolutionized numerous fields, including animal ecology, collective behavior, migration, and conservation biology.

However, satellite communication for localization or data access requires a lot of power, and heavy transmitters greatly limit the ability to track smaller vertebrate species. To address this problem, Ripperger and colleagues developed their WBN -- a system that enables high-resolution tracking of animals weighing as little as 20 grams. These smaller species make up a large proportion of birds and mammals, so WBNs will give researchers new capabilities to address a wide range of questions in animal behavior and ecology.

As reported in the study, WBN is a scalable, flexible system that offers a temporal resolution of seconds, allows automated recording of movement trajectories even in structurally complex habitats such as woodland, and is an ultra-low-power solution for remote data access over distances of several kilometers.

The researchers deployed WBN to study wild bats, creating social networks and flight trajectories of unprecedented quality. To do this, wireless localization nodes are placed in the area of study, and light-weight mobile nodes are attached to the animals. In one example, the authors planted 17 localization nodes in a 1.5-hectare area of German forest, and glued mobile nodes to the fur on the backs of 11 mouse-eared bats, allowing them to track their flights and interactions.

According to the authors, WBNs will greatly benefit biologging of small animal species that move over smaller and more predictable spatial scales, especially inside habitats where signal transmission is constrained. Such setups will allow studies on the effects of social network dynamics on phenomena such as transmission of social information and pathogens, and key ecosystem functions such as pollination and seed dispersal.

Ripperger adds: "Key to success in this project was the close collaboration among biologists, computer scientists, and electrical engineers. Thanks to the high level of miniaturization of the animal-borne tags, we can now collect data of unprecedented quantity and quality that allows us studying the behavior of small animals in much greater detail. For example, we learned from proximity sensing in the wild that noctule bat mothers guide their offspring to novel roosts and that social relationships in vampire bats that formed in the lab persist in the wild. In the future, we plan to expand our work to other taxonomic groups - a method that allows tracking bats is also likely to work for other small animals such as reptiles or songbirds."

Researchers have found strong evidence that the risk for armed conflict is higher after a climate-related disaster, but only in vulnerable countries.

Lead author Tobias Ide from the University of Melbourne said the disasters include storms, floods and droughts - the frequency and intensity of which will increase in the future, due to climate change.

"Bushfires in Australia will not spark a civil war as the state is democratic and able to provide relief," said DECRA Fellow Dr Ide. "But when it comes to droughts in Nigeria or storms in Pakistan, where you have large marginalised populations and little state presence, the picture may well change."

The paper, published today in the Global Environmental Change journal, provides invaluable evidence for policy makers such as the United Nations Security Council, which has been called on to invest in climate adaptation and risk reduction for the millions of people already suffering from the effects of climate change.

"The question 'Will a warming world also be a world with more violent and armed conflicts?' has been a very real one for political leaders and civil societies across the world," Dr Ide said. "Climate change makes tense social and political situations even worse, so climate-change disasters may act like a 'threat multiplier' for violent conflicts.

"Only countries with large populations, the political exclusion of ethnic groups and relatively low levels of economic development, are susceptible to disaster-conflict links. Measures to make societies more inclusive and wealthier are, therefore, no-regrets options to increase security in a warming world."

Research on the effects of climate change have on armed violence have previously been open to interpretation but Dr Ide and his colleagues say their study shows that climate-related disasters enhance armed conflict risks.

"We find that almost one third of all conflict onsets in vulnerable countries over the recent decade have been preceded by a climate-related disaster within seven days," said co-author Carl-Friedrich Schleussner from Climate Analytics. "This does, however, not mean that disasters cause conflicts, but rather that occurrence of disasters increase the risks of an outbreak."

Dr Ide added: "If we look at what happened in Mali when a severe drought occurred in June 2009, we can see that the militant Al-Qaeda in the Islamic Maghreb (AQIM) group exploited the resulting state weakness and desperation of local people to recruit fighter and expand its area of operation. The Philippines were another country where recurrent disasters weakened government structures in contested regions, hence opening a space for rebel groups."

In the large majority of cases, opportunity factors drove the onset of armed violence. Rather than aggrieved populations, rebels exploited the temporary weakness of the state after a disaster, to stage attacks.

Michael Brzoska, a co-author and Associate Senior Researcher from the University of Hamburg, said: "The most surprising result of our study for me was the prevalence of opportunities for armed violence over those related to grievances in post-disaster situations."

The study employed an innovative approach combining different research methods. "For the first time, we brought together statistical analysis on the global level with case study assessments allowing us to assess the robustness of our findings as well as to compare the individual circumstances of each case," said co-author Jonathan Donges from the Potsdam Institute for Climate Impacts Research.

You wait ages for a pterosaur and then four come along at once.

Hot on the heels of a recent paper discovering three new species of pterosaur, University of Portsmouth palaeobiologists have identified another new species - the first of its kind to be found on African soil.

Pterosaurs are the less well-known cousins of dinosaurs. They had adept flying ability - some as large as a fighter jet and others as small as a model aeroplane.

The new species belongs to a group of pterosaurs called tapejarids from the Cretaceous period. Tapejarids were small to medium-sized pterosaurs with wingspans perhaps as wide as four metres, most of which had large, broad crests sweeping up from the front of the skull.

They are well known in Brazil and China, and specimens have also been discovered in Europe, but this is the first time the flying reptile has been found in Africa.

It differs from the three recent species discovered as this one had no teeth - it was 'edentulous'.

Professor David Martill, from the University's School of the Environment, Geography and Geosciences, led the study. He said: "The study of Moroccan material shows that we are still far from having found all the paleontological treasures of North Africa. Even fragmentary fossils, like the jaw piece of the new pterosaur, can give us important information about the biodiversity of the past."

PhD student Roy Smith, one of the co-authors, said: "I feel very privileged to be part of such an exciting discovery. Working in the Sahara was a life-changing experience, and discovering a new species of pterosaur is the icing on the cake."

The new pterosaur has been named Afrotapejara zouhrii to honour the Moroccan palaeontologist Professor Samir Zouhri. Originally a mammal specialist, Zouhri also contributed to several discoveries of prehistoric reptiles in Morocco, including dinosaurs and pterosaurs.

Professor Martill said: "The opportunity to illuminate the diversity of pterosaurs in Africa while honouring a colleague does not happen every day."

The research team included Dr David Unwin from the University of Leicester and Dr Nizar Ibrahim from the University of Detroit Mercy.

Palaeontologist Dr Ibrahim, said: "Samir Zouhri has played an important role in the development of Moroccan palaeontology, not only through his publications, but also because he organised scientific conferences in Morocco and edited an entire volume for the Geological Society of France on the subject of vertebrate palaeontology in Morocco."

The fossil material is part of the collections of the Faculty of Sciences Aïn Chock, Casablanca Hassan II University and the paper was published in Cretaceous Research.

Since its beginnings, quantum mechanics hasn't ceased to amaze us with its peculiarity, so difficult to understand. Why does one particle seem to pass through two slits simultaneously? Why instead of specific predictions can we only talk about evolution of probabilities? According to theorists from universities in Warsaw and Oxford, the most important features of the quantum world may result from the special theory of relativity, which until now seemed to have little to do with quantum mechanics.

Since the arrival of quantum mechanics and the theory of relativity, physicists have lost sleep over the incompatibility of these three concepts (three, since there are two theories of relativity: special and general). It has commonly been accepted that it is the description of quantum mechanics that is the more fundamental and that the theory of relativity that will have to be adjusted to it. Dr. Andrzej Dragan from the Faculty of Physics, University of Warsaw (FUW) and Prof. Artur Ekert from the University of Oxford (UO) have just presented their reasoning leading to a different conclusion. In the article "The Quantum Principle of Relativity", published in the New Journal of Physics, they prove that the features of quantum mechanics determining its uniqueness and its such non-intuitive exoticism - accepted, what's more, on faith (as axioms) - can be explained within the framework of the special theory of relativity. One only has to decide on a certain rather unorthodox step.

Albert Einstein based the special theory of relativity on two postulates. The first is known as the Galilean principle of relativity (which, please note, is a special case of the Copernican principle). This states that physics is the same in every inertial system (i.e., one that is either at rest or in a steady straight line motion). The second postulate, formulated on the result of the famous Michelson-Morley experiment, imposed the requirement of a constant velocity of light in every reference system.

"Einstein considered the second postulate to be crucial. In reality, what is crucial is the principle of relativity. Already in 1910 Vladimir Ignatowski showed that based only on this principle it is possible to reconstruct all relativistic phenomena of the special theory of relativity. A strikingly simple reasoning, leading directly from the principle of relativity to relativism, was also presented in 1992 by Professor Andrzej Szymacha from our faculty," says Dr. Dragan.

The special theory of relativity is a coherent structure that allows for three mathematically correct types of solutions: a world of particles moving at subluminal velocities, a world of particles moving at the velocity of light and a world of particles moving at superluminal velocities. This third option has always been rejected as having nothing to do with reality.

„We posed the question: what happens if - for the time being without entering into the physicality or non-physicality of the solutions - we take seriously not part of the special theory of relativity, but all of it, together with the superluminal system? We expected cause-effect paradoxes. Meanwhile, we saw exactly those effects that form the deepest core of quantum mechanics," say Dr. Dragan and Prof. Ekert.

Initially, both theorists considered a simplified case: space-time with all three families of solutions, but consisting of only one spatial and one time dimension (1+1). A particle at rest in one system of solutions seems to move superluminally in the other, which means that superluminosity itself is relative.

In a space-time continuum constructed this way, non-deterministic events occur naturally. If in one system at point A there is generation of a superluminal particle, even completely predictable, emitted towards point B, where there is simply no information about the reasons for the emission, then from the point of view of the observer in the second system events run from point B to point A, so they start from a completely unpredictable event. It turns out that analogous effects appear also in the case of subluminal particle emissions.

Both theorists have also shown that after taking into account superluminal solutions, the motion of a particle on multiple trajectories simultaneously appears naturally, and a description of the course of events requires the introduction of a sum of combined amplitudes of probability that indicate the existence of superposition of states, a phenomenon thus far associated only with quantum mechanics.

In the case of space-time with three spatial dimensions and one time dimension (3+1), that is, corresponding to our physical reality, the situation is more complicated. The principle of relativity in its original form is not preserved - the subluminal and superluminal systems are distinguishable. However, the researchers noticed that when the principle of relativity is modified to the form: "The ability to describe an event in a local and deterministic way should not depend on the choice of an inertial reference system", it limits the solutions to those in which all the conclusions from the consideration in (1+1) space-time remain valid.

"We noticed, incidentally, the possibility of an interesting interpretation of the role of individual dimensions. In the system that looks superluminal to the observer some space-time dimensions seem to change their physical roles. Only one dimension of superluminal light has a spatial character - the one along which the particle moves. The other three dimensions appear to be time dimensions," says Dr. Dragan.

A characteristic feature of spatial dimensions is that a particle can move in any direction or remain at rest, while in a time dimension it always propagates in one direction (what we call aging in everyday language). So, three time dimensions of the superluminal system with one spatial dimension (1+3) would thus mean that particles inevitably age in three times simultaneously. The ageing process of a particle in a superluminal system (1+3), observed from a subluminal system (3+1), would look as if the particle was moving like a spherical wave, leading to the famous Huygens principle (every point on a wavefront can be treated itself as a source of a new spherical wave) and corpuscular-wave dualism.

"All the strangeness that appears when considering solutions relating to a system that looks superluminal turns out to be no stranger than what commonly accepted and experimentally verified quantum theory has long been saying. On the contrary, taking into account a superluminal system, it is possible - at least theoretically - to derive some of the postulates of quantum mechanics from the special theory of relativity, which were usually accepted as not resulting from other, more fundamental reasons," Dr. Dragan concludes.

For almost a hundred years quantum mechanics has been awaiting a deeper theory to explain the nature of its mysterious phenomena. If the reasoning presented by the physicists from FUW and UO stands the test of time, history would cruelly mock all physicists. The "unknown" theory sought for decades, explaining the uniqueness of quantum mechanics, would be something already known from the very first work on quantum theory.

Physics and Astronomy first appeared at the University of Warsaw in 1816, under the then Faculty of Philosophy. In 1825 the Astronomical Observatory was established. Currently, the Faculty of Physics' Institutes include Experimental Physics, Theoretical Physics, Geophysics, Department of Mathematical Methods and an Astronomical Observatory. Research covers almost all areas of modern physics, on scales from the quantum to the cosmological. The Faculty's research and teaching staff includes ca. 200 university teachers, of which 87 are employees with the title of professor. The Faculty of Physics, University of Warsaw, is attended by ca. 1000 students and more than 170 doctoral students.

The risk for violent clashes increases after weather extremes such as droughts or floods hit people in vulnerable countries, an international team of scientists finds. Vulnerable countries are characterized by a large population, political exclusion of particular ethnic groups, and low development. The study combines global statistical analysis, observation data and regional case study assessments to yield new evidence for policy-makers.

"Climate disasters can fuel some smoldering conflicts - this is a worrying insight since such disasters are on the rise," says Jonathan Donges at the Potsdam Institute for Climate Impact Research, Germany, co-author of the paper now published in Global Environmental Change. "Ongoing greenhouse gas emissions from fossil fuels are, if unmitigated, destabilizing our climate. More frequent and more severe weather extremes are one of the effects. The new study adds important evidence and hence robustness to conflict analyses we've done in the past few years."

"One third of all conflict onsets in vulnerable countries" is affected

The numbers are quite staggering. "We find that almost one third of all conflict onsets in vulnerable countries over the recent decade have been preceded by a climate-related disaster within 7 days," says co-author Carl-Friedrich Schleussner from Climate Analytics in Berlin, Germany. "This does, however, not mean that disasters cause conflicts, but rather that disaster occurrence increases the risks of a conflict outbreak." After all, conflict is human-made. The analysis of concrete cases of disaster-conflict co-occurences shows that most such cases are not mere coincidences, but likely linked by causal mechanisms - this is one of the key new findings.

In Mali for instance a severe drought occurred in 2009 after which the militant Al-Qaeda in the Islamic Maghreb exploited the resulting state weakness and desperation of local people to recruit fighters and expand its area of operation. Other examples analyzed include China, the Philippines, Nigeria, and Turkey. India turns out to be the country with the by far highest number of disaster-conflict coincidences. The most surprising result of the study, says co-author Michael Brzoska from the University of Hamburg, was the prevalence of opportunities for armed violence over those related to grievances in post-disaster situations.

"Measures to make societies more inclusive and wealthier are no-regrets options"

"Climate-related disasters may act like a 'threat multiplier' for violent conflicts," explains Tobias Ide from the University of Melbourne. A most important finding of the study is that only countries with large populations, the political exclusion of ethnic groups and relatively low levels of economic development are susceptible to disaster-conflict links. Optimistically, Ide concludes: "Measures to make societies more inclusive and wealthier are, therefore, no-regrets options to increase security in a warming world."

Sustainable energy storage is in great demand. Researchers at Uppsala University have therefore developed an all-organic proton battery that can be charged in a matter of seconds. The battery can be charged and discharged over 500 times without any significant loss of capacity. Their work has been published in the scientific journal Angewandte Chemie.

The researchers have been able to demonstrate that their battery can be easily charged using a solar cell. Charging can also be accomplished without the aid of the advanced electronics that, for example, lithium batteries require. Another advantage of the battery is that it is unaffected by ambient temperature.

"I'm sure that many people are aware that the performance of standard batteries declines at low temperatures. We have demonstrated that this organic proton battery retains properties such as capacity down to as low as -24°C," says Christian Strietzel of Uppsala University's Department of Materials Science and Engineering.

A great many of the batteries manufactured today have a major environmental impact, not least due to the mining of the metals used in them.

"The point of departure for our research has therefore been to develop a battery built from elements commonly found in nature and that can be used to create organic battery materials," explains Christian Strietzel.

For this reason, the research team has chosen quinones as the active material in their battery. These organic carbon compounds are plentiful in nature, among other things occurring in photosynthesis. The characteristic of quinones that researchers have utilised is their ability to absorb or emit hydrogen ions, which of course only contain protons, during charging and discharging.

An acidic aqueous solution has been used as an electrolyte, the vital component that transports ions inside the battery. As well as being environmentally friendly, this also provides a safe battery free from the hazard of explosion or fire.

"There remains a great deal of further development to be done on the battery before it becomes a household item; however, the proton battery we have developed is a large stride towards being able to manufacture sustainable organic batteries in future," says Christian Strietzel.

Open biomass burning (OBB) has a significant impact on regional air quality, especially on the heavy haze pollution in Northeast China (NEC) in recent years. Recent research published in Atmospheric and Oceanic Science Letters provides scholars and decision-makers with a more comprehensive and long-term analysis of the spatiotemporal patterns of OBB in NEC.

By using the MODIS fire and land cover products, Dr Lili Wang from the Institute of Atmospheric Physics, Chinese Academy of Sciences attempted to capture the spatial and temporal distribution of OBB in NEC from 2003 to 2017, as well as the corresponding proportion of fire points in different vegetation types.

The results show the changes in the total number of MODIS fire points in NEC from 2003 to 2017 demonstrated a fluctuating but generally rising trend, with the peak during 2013-2017.

"We found that most fire points concentrated in two key periods, i.e., March-April and October-November. OBB in Heilongjiang Province comprised a major proportion of the total number of fire spots in NEC, and the largest proportion of all fires was in cropland," says Dr Wang.

According to this study, the cumulative emissions of PM2.5, NOx and NH3 from open agricultural burning reached up to 158.46 Gg, 49.50 Gg, and 27.00 Gg in March, April, October, and November during 2013-17, respectively. Significantly, the majority of OBB generally shifted from October-November to March-April for all three provinces and the amount of OBB in March-April was higher than that in October-November during 2016-17.

Dr Wang suggests more effective utilization approaches for crop residue and strict policies should be taken to control the upward trend of crop residue burning in NEC. In addition, prescribed in-situ burning could be an effective straw management strategy if farmers are reluctant to give up this traditional farming method.

Doctors need to pay particular attention to patients with endocrine disorders and diabetes mellitus in relation to COVID-19 infections, say leading endocrinologists.

In an editorial published in the Journal of Clinical Endocrinology & Metabolism, they say data from Wuhan province in China, where the pandemic started, has revealed that patients with diabetes mellitus were over-represented in the group of people who become severely ill and also among those who died.

The endocrinologists, who are experts in hormone-related diseases, say medical teams need to be extra vigilant when they are dealing with this patient group.

According to Diabetes UK, 4.7 million people in the UK have diabetes mellitus.

Paul Stewart, editor in chief of the journal and Professor of Medicine at the University of Leeds, said: "There is early evidence from China that those patients who have endocrinological disorders face additional risks from COVID-19.

"The scientific picture indicates that these people need to self-isolate, to try and reduce the chance of infection in the same way as the background population. There are endocrinological disorders that affect the body's ability to make steroid hormones - or glucocorticoids - to help overcome infection. This might make some patients more vulnerable to the effects of the COVID-19 illness."

Patients with known problems of the adrenal gland are treated with replacement glucocorticoid on a daily basis - such patients who begin to develop symptoms of COVID-19 should double their dose of medication immediately: they should follow their "sick day rules", the protocol they have agreed with their doctor to follow when they feel unwell, until any fever subsides.

However, there are many other patients who take glucocorticoids because of inflammatory diseases. Some of these patients take large doses and that may suppress their immune systems and importantly prevent the body's ability to respond to COVID-19.

Whilst glucocorticoid treatment has no role to play in the treatment of COVID-19 per se, intravenous stress doses should be considered by doctors in any patient previously treated with glucocorticoids who is deteriorating with COVID-19.

These recommendations apply to specific patient groups. People should not change their medication regime without first talking to their doctor.

When do cells decide to divide? For 40 years, the textbook answer has been that this decision occurs in the first phase of a cell's existence - right after a mother cell divides to become daughter cells.

But researchers at CU Boulder have found that it's actually the mother cell that determines if its daughter cells will divide. The finding, explained in a new study out today in Science, sheds new light on the cell cycle using modern imaging technologies, and could have implications for cancer drug therapy treatments.

"We see something different than what's in the textbooks," said Sabrina Spencer, senior author of the paper and assistant professor of biochemistry.

Cells choose to divide based on the amount of mitogens, or growth factors, they sense in their environment. The availability of mitogens drives the signal to proliferate: duplicate cellular contents and divide into two daughter cells. This is all part of the cell cycle.

Cancer cells can enter the cell cycle even if growth factors aren't there, said Spencer. That's part of why they proliferate so much - the cell cycle becomes dysregulated and growth continues unchecked.

Better understanding of why and when cells choose to proliferate, could help scientists tailor or expand the timing of cancer drug therapies.

In their experiments, the researchers found that rather than daughter cells deciding on their own whether to divide, they committed to another cell cycle or not immediately after division of the mother cell. This implies the decision was made in the previous cell cycle, because the daughter cells were already born on one path or another, according to Spencer.

"That got us thinking that maybe all the sensing of the environment is actually happening in the mother cell cycle," said Spencer.

Previous textbook experiments had to first remove all growth factors in order to synchronize the cells' cycling, which perturbs cell cycle behavior. But this new research used time lapse microscopy and cell tracking technologies, which allowed the scientists to film cells doing their own thing, on their own time.

"Doing the experiment this way led to very different results," said Spencer.

The researchers tracked thousands of cells across 48 hours, using computational cell tracking - which can track the same cell through hundreds of sequential images.

Even 10 years ago, very few labs could track cells even for a couple of hours, said Spencer.

Signals and memory

Their next question was: when in the mother cell cycle does a cell decide if its daughter cells will divide?

To answer this, the researchers removed and replaced the growth factors - which give the signal for the cell to divide - for several hours at different phases in the mother cell cycle.

They found that the longer these growth factors were removed in the mother cell, the less likely the daughter cells were to divide. If the growth factors were removed for more than nine hours, none of the daughter cells ended up dividing.

"We found that no matter when you blocked this signaling, cells can sense it," said Mingwei Min, first author and postdoctoral researcher in the Department of Biochemistry and BioFrontiers Institute. "And not only can they sense it, they can remember that information for many hours, all the way through to the daughter cell cycle."

If cells are continually sensing growth factor signaling - as this new paper found - instead of only in the first phase of the daughter cycle, cancer drugs may have a longer window than previously believed to provide therapeutic effects.

But how are cells remembering the availability of growth factors? The key lies in a protein known as Cyclin D.

Normally, Cyclin D rises up in the second half of the cell cycle in the mother cell. But when growth factors were removed and replaced in the experiment, there was less Cyclin D at the end of the mother cell cycle, the study found.

And without as much Cyclin D, the daughter cells have less of the thing they need to be able to divide.

"The fact that cells can store memory - or integrate past history - of growth factor availability is a new finding," said Spencer. "The combination of fluorescent sensor design, long-term time-lapse microscopy, and cell tracking is really our forte that enabled this discovery."

New research from Stanford University has found that stress can hinder our ability to develop informed plans by preventing us from being able to make decisions based on memory.

"We draw on memory not just to project ourselves backward into the past but to project ourselves forward, to plan," said Stanford psychologist Anthony Wagner, who is the senior author of the paper detailing this work, published April 2 in Current Biology. "Stress can rob you of the ability to draw on cognitive systems underlying memory and goal-directed behavior that enable you to solve problems more quickly, more efficiently and more effectively."

Combined with previous work from Wagner's Memory Lab and others, these findings could have broad implications for understanding how different people plan for the future - and how lack of stress may afford some people a greater neurologically-based opportunity to think ahead.

"It's a form of neurocognitive privilege that people who are not stressed can draw on their memory systems to behave more optimally," said Wagner, who is the Lucie Stern Professor in the Social Sciences at Stanford's School of Humanities and Sciences. "And we may fail to actually appreciate that some individuals might not be behaving as effectively or efficiently because they are dealing with something, like a health or economic stressor, that reduces that privilege."

Take a virtual walk

The researchers conducted experiments where they monitored participants' behavior and brain activity - via fMRI - as they navigated through virtual towns. After participants became very familiar winding routes in a dozen towns, they were dropped onto one of the memorized paths and told to navigate to a goal location.

To test the effects of stress, the researchers warned some participants that they could receive a mild electric shock, unrelated to their performance, during their virtual rambles. Participants who didn't have to worry about being randomly shocked tended to envision and take novel shortcuts based on memories acquired from prior journeys, whereas the stressed participants tended to fall back on the meandering, habitual routes.

Prior to beginning their trek, the participants were virtually held in place at their starting position. Brain scans from this period showed that the stressed individuals were less likely than their counterparts to activate the hippocampus - a brain structure that would have been active if they were mentally reviewing previous journeys. They also had less activity in their frontal-parietal lobe networks, which allows us to bring neural processes in line with our current goals. Previous work by the researchers had found that stress hinders this neural machinery, making it harder for us to retrieve and use memories.

The researchers believe their new study is the first to show how hippocampal-frontal lobe network disruption takes memory replay offline during a planning session due to stress.

"Its kind of like our brain is pushed into a more low-level thought-process state, and that corresponds with this reduced planning behavior," said Thackery Brown, who was a postdoctoral scholar in the Memory Lab during this research and is lead author of the paper.

Stress and old age

Looking forward, the researchers are especially interested in how the relationship between stress and memory affects older populations, who often experience both health and economic issues. Older people are also more likely to be concerned about memory loss. Together, these combined stressors could contribute to a diminished ability to remember, which could further exacerbate their stress and also impair their ability to deal with it.

Brown has begun conducting studies similar to the virtual navigation experiments with participants between the ages of 65 and 80 to try to better understand how the associations between stress, memory and planning play out in older populations.

"It's a powerful thing to think about how stressful events might affect planning in your grandparents," said Brown, who is now an assistant professor at Georgia Institute of Technology. "It affects us in our youth and as we interact with and care for older members of our family, and then it becomes relevant to us in a different way when we are, ourselves, older adults."

Limited global supplies may scupper proposals to use the antimalarial drugs, chloroquine and hydroxychloroquine, to lessen the symptoms of Covid-19 infection or ward it off altogether, say Italian doctors in a letter published online today in the Annals of the Rheumatic Diseases.

The results of preliminary lab tests have prompted scientists to propose that these drugs be used to treat patients with pneumonia caused by Covid-19 infection. This approach has already been included in Chinese guidelines on how best to manage the disease.

Various studies over the past decade have shown that antimalarial drugs can lessen the impact of viral infections, including Covid-19. And clinical trials are now under way to see whether these drugs might help ward off the disease altogether.

Chloroquine and hydroxychloroquine have been used to treat autoimmune disease, including rheumatic diseases, since the 1940s, and have proved safe and well tolerated in most cases, say the authors.

Side effects are generally mild to moderate, with serious complications, such as retinal and cardiac damage, rare and related to cumulative doses over a long period of time.

There is an ethical issue, however, as there is as yet no hard evidence from clinical trials that these drugs can prevent the spread of Covid-19, they point out.

"Is it permissible to take a controlled risk in the event of a pandemic?" they ask. "In such a case: would it be reasonable to consider antimalarials as primary prophylaxis in healthy subjects living in highest risk regions or, at least, to use them in those testing positive for Covid-19, but still asymptomatic?"

The safety and effectiveness of these drugs makes them good candidates for mass preventive treatment programmes, they add, and scientists seem to be leaning towards adopting this approach.

But, conclude the authors: "If mass prophylaxis was accepted as an option worldwide, this would raise the question of whether there is enough supply of [chloroquine] and [hydroxychloroquine] to support this approach."

The European League Against Rheumatism (EULAR), which co-owns the Annals of the Rheumatic Diseases with BMJ, says that the use of these drugs to tackle Covid-19 could have serious implications for people with rheumatic diseases across Europe.

EULAR President, Professor Iain McInnes, says that global efforts to boost the evidence base for the use of these antimalarial drugs to treat Covid-19 are extremely welcome.

But he adds: "EULAR is concerned, however, that the diversion of drug supplies away from people with rheumatic and musculoskeletal diseases may compromise the health of this important and sizeable group of patients in Europe and beyond."

EULAR's patient membership group (PARE) is now calling on the manufacturers of these drugs to rapidly increase production to meet the projected surge in demand.

"A balanced approach that meets the imperatives of the ongoing pandemic, but which also takes account of the needs of patients already taking these drugs is essential," insists Professor McInnes.

New research has found that allotment gardening promotes positive body image, which measures someone's appreciation of their own body and its functions, and an acceptance of bodily imperfections.

The study, published in the journal Ecopsychology and led by Professor Viren Swami of Anglia Ruskin University (ARU), involved 84 gardeners from 12 urban allotment sites in north London.

Through a series of questionnaires, it found that the gardeners had significantly higher levels of body appreciation, significantly higher levels of body pride, and significantly higher levels of appreciation for their body's functionality, compared to a group of 81 non-gardeners, recruited from the same area of London.

The study also discovered that the longer period of time the participants spent gardening, the larger the improvement in positive body image when they left their allotment.

Previous research has shown that gardening is associated with improved psychological wellbeing and physical health. This new study adds to previous work by Professor Swami demonstrating that exposure to natural environments helps to promote positive body image.

Viren Swami, Professor of Social Psychology at Anglia Ruskin University (ARU), in Cambridge, and Perdana University, in Malaysia, said: "Positive body image is beneficial because it helps to foster psychological and physical resilience, which contributes to overall wellbeing.

"My previous research has shown the benefits of being in nature more generally, but increasing urbanisation has meant that many people now have less access to nature.

"The findings from this new study are important because they specifically show the significant benefits of spending time on allotments, which are typically quite small patches of green space in otherwise mainly urban environments.

"Ensuring that opportunities for gardening are available to all people is, therefore, vital and may help to reduce the long-term cost burden on health services. One way to achieve this, beyond policies that ensure access to nature for all citizens, would be through the provision of dedicated and sustained community allotment plots."

A group of scientists, physicians, funders, and policy makers from over 70 institutions from over 30 countries have launched an international coalition to respond to COVID-19 in resource-poor settings. The COVID-19 Clinical Research Coalition aims to accelerate desperately needed COVID-19 research in those areas where the virus could wreak havoc on already-fragile health systems and cause the greatest health impact on vulnerable populations.

In a Comment published today in The Lancet, the members of the coalition argue that international research collaboration and coordination is needed urgently to support African, Latin American, Eastern European, and certain Asian countries to respond effectively to the worsening pandemic and speed up research adapted to resource-limited settings.

The coalition brings together an unprecedented array of health experts, including public-sector research institutes, ministries of health, academia, not-for-profit research and development organizations, NGOs, international organisations, and funders all committed to finding COVID-19 solutions for resource-poor settings.

One important research response to COVID-19 has been launched already, the World Health Organization (WHO)-led SOLIDARITY trial, an unprecedented global effort. But the authors found that out of almost 600 COVID-19 clinical trials registered, very few trials are planned in resource-poor settings. The authors commit to sharing their technical expertise and clinical trial capability to accelerate COVID-19 research in these settings.

The scale of the challenge is clearly beyond the scope of any single organization. The coalition will facilitate a coordinated approach, so that all data from all regions can be collected in a similar fashion, pooled and shared in real-time. This will help countries and the WHO to make rapid evidence-based decisions on policies and practice.   

"We welcome the launch of this coalition, which takes advantage of existing multinational and multidisciplinary expertise in running clinical trials in resource poor settings, and will help the World Health Organization in its coordinating role in the global response to COVID-19," said Dr Soumya Swaminathan, Chief Scientist, World Health Organization. "Although the epicentre is today elsewhere, we must prepare now for the consequences of this pandemic in more resource-constrained settings or we stand to lose many more lives."

Members of the coalition call for specific commitments to ensure access, so that effective new treatments are made available as soon as possible in resource-poor settings and are affordable and readily accessible.