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What The Study Did: Researchers quantified the added burden of fatal opioid overdoses occurring in Ontario, Canada, during the first six months of the COVID-19 pandemic.

Authors: Tara Gomes, Ph.D., of the Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital in Toronto, is the corresponding author.

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

(doi:10.1001/jamanetworkopen.2021.12865)

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

Researchers at McGill University have gained new insight into the workings of perovskites, a semiconductor material that shows great promise for making high-efficiency, low-cost solar cells and a range of other optical and electronic devices.

Perovskites have drawn attention over the past decade because of their ability to act as semiconductors even when there are defects in the material's crystal structure. This makes perovskites special because getting most other semiconductors to work well requires stringent and costly manufacturing techniques to produce crystals that are as defect-free as possible. In what amounts to the discovery of a new state of matter, the McGill team has made a step forward in unlocking the mystery of how perovskites pull off this trick.

"Historically, people have been using bulk semiconductors that are perfect crystals. And now, all of a sudden, this imperfect, soft crystal starts to work for semiconductor applications, from photovoltaics to LEDs," explains senior author Patanjali Kambhampati, an associate professor in the Department of Chemistry at McGill. "That's the starting point for our research: how can something that's defective work in a perfect way?"

Quantum dots, but not as we know them

In a paper published May 26 in Physical Review Research, the researchers reveal that a phenomenon known as quantum confinement occurs within bulk perovskite crystals. Until now, quantum confinement had only been observed in particles a few nanometres in size - the quantum dots of flatscreen TV fame being one much-vaunted example. When particles are this small, their physical dimensions constrain the movement of electrons in a way that gives the particles distinctly different properties from larger pieces of the same material - properties that can be fine-tuned to produce useful effects such as the emission of light in precise colours.

Using a technique known as state-resolved pump/probe spectroscopy, the researchers have shown a similar type of confinement occurs in bulk caesium lead bromide perovskite crystals. In other words, their experiments have uncovered quantum dot-like behaviour taking place in pieces of perovskite significantly larger than quantum dots.

Surprising result leads to unexpected discovery

The work builds on earlier research which established that perovskites, while appearing to be a solid substance to the naked eye, have certain characteristics more commonly associated with liquids. At the heart of this liquid-solid duality is an atomic lattice able to distort in response to the presence of free electrons. Kambhampati draws a comparison to a trampoline absorbing the impact of a rock thrown into its centre. Just as the trampoline will eventually bring the rock to a standstill, the distortion of the perovskite crystal lattice - a phenomenon known as polaron formation - is understood to have a stabilizing effect on the electron.

While the trampoline analogy would suggest a gradual dissipation of energy consistent with a system moving from an excited state back to a more stable one, the pump/probe spectroscopy data in fact revealed the opposite. To the researchers' surprise, their measurements showed an overall increase in energy in the aftermath of polaron formation.

"The fact that the energy was raised shows a new quantum mechanical effect, quantum confinement like a quantum dot," Kambhampati says, explaining that, at the size scale of electrons, the rock in the trampoline is an exciton, the bound pairing of an electron with the space it leaves behind when it is in an excited state.

"What the polaron does is confine everything into a spatially well-defined area. One of the things our group was able to show is that the polaron mixes with an exciton to form what looks like a quantum dot. In a sense, it's like a liquid quantum dot, which is something we call a quantum drop. We hope that exploring the behavior of these quantum drops will give rise to a better understanding of how to engineer defect-tolerant optoelectronic materials."

A newly released scientific paper in Nature Publishing's Scientific Reports Journal has revealed unprecedented amounts of highly toxic mercury are deposited in the deepest trenches of the Pacific Ocean.

The study, a multi-national effort involving scientists from Denmark, Canada, Germany and Japan, reports the first-ever direct measurements of mercury deposition into one of the logistically most challenging environments to sample on Earth, and the deepest at eight to 10 kilometers under the sea.

Lead author Professor Hamed Sanei, Director of the Lithospheric Organic Carbon Laboratory (LOC) at the Department of Geoscience, Aarhus University, stated the amount of mercury discovered in this area exceeds any value ever recorded in remote marine sediments, and is even higher than many areas directly contaminated by industrial releases.

"The bad news is that these high mercury levels may be representative of the collective increase in anthropogenic emissions of Hg into our oceans," he said. "But the good news is that ocean trenches act as a permanent dump, and so we can expect the mercury that does end up there will be buried for many millions of years. Plate tectonics will carry these sediments deep into the earth's upper mantle".

"But even as mercury is being removed from the biosphere, it remains quite alarming how much mercury has ended up in the ocean trenches. This may be an indicator of the overall health of our oceans."

Co-author Dr. Peter Outridge, a research scientist with Natural Resources Canada and lead author of the United Nations' Global Mercury Assessment, said: "The results of this research help fulfill a key knowledge gap in the mercury cycle, i.e. the true rate of mercury removal from the global environment into deep-ocean sediments." He added, "We have shown that sediments in the ocean trenches are mercury accumulation 'hotspots', with mercury accumulation rates many times higher than were previously believed to be present."

Co-author Ronnie Glud, Professor and Director of the Hadal Centre at the University of Southern Denmark, who was scientific leader of this multi-national expedition to the ocean trenches, said: "This paper calls for extensive additional sampling of the deep-ocean and in particular hadal trenches to support this preliminary work. Ultimately this will improve the accuracy of environmental mercury models and the management of global mercury pollution."

The farming of livestock to feed the global appetite for animal products greatly contributes to global warming. A new study however shows that emission intensity per unit of animal protein produced from the sector has decreased globally over the past two decades due to greater production efficiency, raising questions around the extent to which methane emissions will change in the future and how we can better manage their negative impacts.

Despite what we know about the environmental cost of livestock production, the global appetite for animal products such as meat, eggs, and dairy continues to grow. The livestock sector is in fact the largest source of manmade methane emissions globally, and these emissions are projected to keep increasing along with the growing demand for livestock products. This is bad news for the planet as methane - the second most abundant manmade greenhouse gas after carbon dioxide (CO2) - has a warming effect 28 times greater per kilogram than that of CO2 over a 100-year period.

Following the recent revision of the Intergovernmental Panel on Climate Change (IPCC)'s emission factors and methodology for livestock methane emissions, an international team of researchers led by IIASA guest researcher Jinfeng Chang, set out to re-assess global livestock methane emissions over the past two decades and project emissions till 2050. Their study just published in AGU Advances, is the first to apply the revised IPCC guidelines globally and assess the resulting differences in future projections of methane emissions.

The study's investigation covered three questions: firstly, the team wanted to determine the ranges of estimates of livestock methane emissions and emission intensities using the different methodological tiers and versions of the IPCC guidelines (the 2006 version and the more recent 2019 refinement). Secondly, they wanted to find out how the intensity of livestock methane emissions has changed over the past few decades, and how these changes differ among countries/regions. Lastly, the researchers explored to what extent the methane emissions from the livestock sector will change in the future, how much mitigation potential exists and what form it should take, as well as where such mitigation actions might be most effective.

While total emissions for the sector continue to increase, the findings indicate that emission intensity actually decreased overall for most livestock categories globally between 2000 and 2018 per kilogram of protein (in products including milk and meat from cattle, buffaloes, goats, and sheep; meat from pigs; and meat and eggs from poultry). A regional analysis provided a more nuanced picture, showing that while intensities may be decreasing across the board, regional differences remain. These variations in intensity can mainly be attributed to differences in productivity, which can in turn be explained by differences in diet and/or grazing intensity, with a less nutritious/digestible diet (e.g., low protein and high fiber) and/or more extensive grazing (for ruminants specifically) leading to higher emissions. For pigs and poultry, the management of manure accounted for the majority of methane emissions. Regional differences in emission intensities were also influenced by climate (with warmer climate enhancing emissions) and the manure management system employed.

According to the researchers, a continued overall downward trend in methane emissions from the livestock sector could provide a large potential to mitigate livestock emissions.

"The continuation of the past decreases in emission intensity provides a large potential to mitigate livestock emissions, especially in a number of developing countries in Africa, Asia, and South America. Efforts on the demand-side to promote balanced, healthy, and environmentally sustainable diets in most countries can mitigate future livestock methane emissions, but will not be sufficient for livestock methane emission mitigation without parallel efforts to improve production efficiency and decrease the emission intensity per unit of protein produced," explains Chang.

According to Chang, efforts to decrease emission intensity should be prioritized in developing countries with the largest mitigation potential as improving production efficiency has a much greater mitigating effect than demand-side efforts. In this regard, China, India, and South Africa emerged as the three countries with the highest mitigation potential.

"From our projections until 2050, sustainable diets are projected to result in 190-206 teragrams (Tg) less methane emissions in total (aggregated from 2012 to 2050) compared to a business as usual scenario, resulting in a 3-4% mitigation of accumulated emissions from 2012 to 2050. Improving efficiency, on the other hand, can result in 821-1,077 Tg less methane emissions in total than business as usual under constant intensity - a four-fold larger mitigation potential - thus mitigating total emissions by 15-16%," adds Chang.

In light of the above, the researchers however emphasize that their findings do not imply that they endorse the industrial livestock system for methane mitigation, as it causes many other environmental problems like pollution from failed manure management, and land-use change for grain and high-quality fodder cultivation. They point out that there are many other, more sustainable ways to improve efficiency and that improvements to livestock production efficiency should take place in line with the natural circumstances in the respective regions. For example, in semi-arid regions where increasing crop production for feeding livestock is impossible due to water limitations, such as in Central Asia, improving grazing management to increase productivity should be prioritized as a sustainable solution rather than moving from low to industrialized systems.

"An optimal strategy should always consider other relevant sustainability goals like biodiversity, water pollution through nutrient runoff, and the potential implications for livelihoods and resilience to climate change impacts," Chang concludes.

The biological clock is present in almost all cells of an organism. As more and more evidence emerges that clocks in certain organs could be out of sync, there is a need to investigate and reset these clocks locally. Scientists from the Netherlands and Japan introduced a light-controlled on/off switch to a kinase inhibitor, which affects clock function. This gives them control of the biological clock in cultured cells and explanted tissue. They published their results on 26 May in Nature Communications.

Life on Earth has evolved under a 24-hour cycle; of light and dark, hot and cold. 'As a result, our cells are synchronized to these 24-hour oscillations,' says Wiktor Szymanski, Professor of Radiological Chemistry at the University Medical Center Groningen. Our circadian clock is regulated by a central controller in the suprachiasmatic nucleus, a region in the brain directly above the optic nerve, but all our cells contain a clock of their own. These clocks consist of an oscillation in the production and breakdown of certain proteins.

Light switch

'It is becoming increasingly clear that these clocks can be disrupted in organs or tissues, which may lead to disease,' adds first author Dušan Kolarski, a PhD student from the group led by Ben Feringa, Professor of Organic Chemistry. And, of course, we all know about jet lag, which is caused by travel across time zones, or problems that are caused by the switch to or from daylight saving time. 'We know very little about how our cells coordinate these oscillations, or how it affects the body if, for example, one kidney is out of phase with the rest of the body,' he adds.

To study these effects, it would be useful to have a drug that affects the clocks and that can be activated locally. The latter is something that the groups of Szymanski and Feringa have done before. They created several compounds, such as antibiotics or anticancer drugs, that could be switched on and off with light. Previously, circadian biologist Tsuyoshi Hirota, associate professor at the Institute of Transformative Bio-Molecules at Nagoya University, Japan, developed a kinase inhibitor, longdaysin, which slows down the circadian clock to a cycle that lasts up to 48 hours. Kolarski fitted this longdaysin with a light switch that allowed him to activate or deactivate the compound with violet and green light, respectively.

Time zone

Developing this adaptation took Kolarski several years, but the result was well worth the effort. 'It was a real scientific "Tour de Force" and a beautiful example of interdisciplinary cooperation', adds Feringa. Together with their Japanese colleagues at Nagoya University, the scientists from the University of Groningen showed how the cycle of cultured cells was extended from 24 to 28 hours by treatment with the longdaysin derivative. Deactivation with green light brought the cycle back to just over 25 hours and subsequent reactivation with violet light returned it to 28 hours. 'We also used it in tissue slices from the mouse suprachiasmatic nucleus,' says Kolarski. 'The oscillations slowed to a 26-hour cycle after treatment for several days with the longdaysin derivative and returned to a 24-hour cycle after deactivation with green light.' 'This reversible regulation will provide a new approach to analysing how the clock in each cell is organized at the tissue level to gain a deeper understanding of the complex circadian clock system,' Hirota adds.

The scientists also adjusted the phase of the cycles in cultured cells: a three-day activation of the longdaysin derivative followed by deactivation caused a shift in the 24-hour cycle by up to six hours. This is as if the cells were synchronized with a different time zone. The experiments are a proof of principle and will allow scientists to study the circadian clock in much more detail. A next step would be to use longdaysin in animals. Kolarski: 'The original longdaysin, without the switch, has been used before in zebrafish. We would very much like to test it in mice. The aim is not to fix jet lag but to study the effect of longdaysin on physiology.'

Organs

A light-activated drug such as longdaysin will probably only be used to treat serious conditions. 'We can actually reach quite a few organs with light, for example with an endoscope. The gastrointestinal tract and the respiratory system are easily reached, while other tissues may require small incisions to insert optic fibres,' comments Szymanski. There are also several emerging options to generate light inside organs or tissues, through techniques such as bioluminescence or sonoluminescence. Although these levels of light are still several orders of magnitude below what we need to flick a switch. We will work hard to increase sensitivity in the coming years, emphasize both Szymanski and Feringa. Kolarski adds: 'We have now opened a new field of study. Eventually, all this will allow us to locally disrupt or repair the circadian oscillations.'

Simple Science Summary

Oncotarget published "Creation of a new class of radiosensitizers for glioblastoma based on the mibefradil pharmacophore" which reported that this group previously identified a calcium channel blocker, mibefradil, as a potential GBM radiosensitizer. They discovered that mibefradil selectively inhibits a key DNA repair pathway, alternative non-homologous end joining.

Then, they initiated a phase I clinical trial that revealed promising initial efficacy of mibefradil, but further development was hampered by dose-limiting toxicities, including CCB-related cardiotoxicity, off-target hERG channel and cytochrome P450 enzymes interactions.

Here, the authors show that mibefradil inhibits DNA repair independent of its CCB activity, and report a series of mibefradil analogues which lack CCB activity and demonstrate reduced hERG and CYP activity while retaining potency as DNA repair inhibitors. They also report a targeted siRNA-based screen which suggests a possible role for mTOR and Akt in DNA repair inhibition by this class of drugs.

Taken together, these Oncotarget data reveal a new class of mibefradil-based DNA repair inhibitors which can be further advanced into pre-clinical testing and eventually clinical trials, as potential GBM radiosensitizers.

These Oncotarget data reveal a new class of mibefradil-based DNA repair inhibitors which can be further advanced into pre-clinical testing and eventually clinical trials, as potential GBM radiosensitizers.

Dr. Yulia V. Surovtseva and Dr. Ranjit S. Bindra from Yale University said, "Glioblastoma (GBM) is the most common primary malignant tumor of the central nervous system (CNS)."

Cells utilize several DNA double-strand break repair pathways to repair DNA damage induced by irradiation.

This pathway repairs only 0.5–1% of total DSBs, but serves as a crucial back-up pathway for both NHEJ and HR and for the repair of complex DNA lesions arising from IR-induced damage .

The EJ-DR assay was utilized in a high-throughput chemical screen for novel DNA repair inhibitors, which identified the T-type and L-type calcium channel blocker, mibefradil, as a selective inhibitor of alt-NHEJ repair.

Based on these findings, the authors sought to create a new class of radiosensitizers which retained mibefradil's activity as a DNA repair inhibitor, but showed reduced hERG and CYP450 enzyme inhibition.

Finally, through the knockdown of DNA damage response proteins in the high-throughput imaging-based assay, we identified potential targets or regulators of mibefradil, which phenocopied the selective inhibition of alt-NHEJ over HR.

The Surovtseva/Bindra Research Team concluded in their Oncotarget Research Output that, the use of DNA repair inhibitors as radiosensitizers in GBM could represent a viable approach to achieve better response owing to the range of DDR pathways activated in response to radiation-induced DNA damage.

Additionally, the identification of selective inhibitors of alt-NHEJ could also be tested in other settings where alt-NHEJ activity is critical, such as in HR-deficient tumors.

The synthesis and validation of the mibefradil analogue, YU252386, shows great promise towards the development of a potent and selective radiosensitizer for GBMs and beyond, and warrants further in vivo study in clinically relevant GBM models.

Metasurface holograms (meta-holograms) are ultra-thin artificial surfaces designed to shape incident light and project it to extremely wide angles. Meta-holograms have opened up numerous possibilities such as light multiplexing, information processing, 3D display, high-density data storage, and optical encoding. Despite of these remarkable advances, the road to practical applications of meta-holograms is hindered by artifacts that originate from strong interactions between the building blocks of the meta-holographic surface and inevitable fabrication defects, ultimately causing distortion and degradation to the holographic image. The small dimensions of the meta-hologram, together with the random nature of fabrication defects, make the artifacts problem extremely difficult to correct.

In a new paper published in Light Science & Application, a team of scientists, led by Hui Cao from Yale University, USA, Qinghai Song and Shumin Xiao from Harbin Institute of Technology (Shenzhen), China, and co-workers have developed an efficient method to suppress the holographic artifacts while maintaining the image quality. Their method is based on fine-tuning of the coherence of illumination, implemented with a degenerate cavity laser, a unique class of lasers which allows a precise and continuous tuning of the spatial coherence of emission with little change in total power and temporal coherence.

The majority of lasers operates with a single or a few spatial modes, and produces highly coherent emission. When the laser light is used to illuminate a meta-hologram, the interference of scattered waves produce coherent artifacts and severely distort the images. The scientists gradually decrease the coherence of laser illumination to amend the holographic artifacts. However, if the coherence is too low, the fine details of the holographic image will blur. Thus it is essential to find the optimal degree of coherence to suppress artifacts without a significant loss of spatial resolution. This was realized with a novel laser source whose spatial coherence of emission can be tuned gradually, accurately and efficiently.

The scientists summarize the operational principle of their novel technique:

"We design a bright laser source with a precise and continuous tuning of the spatial coherence. The tuning is remarkably energy efficient with low power variation. The laser is then used to illuminate a meta-hologram. The precise tuning allows reaching the right level of coherence required to suppress the coherent artifacts without significant blurring of the holographic image."

"Compared to the existing methods of lowering the coherence of conventional lasers, our degenerate cavity laser exhibits extremely fast decoherence, thus enabling high-speed artifact-free meta-holography with no pre- or post-processing of any kind." they added.

"The new method can be used to dramatically enhance the image quality of compact, dynamical holographic projection displays. This breakthrough will open a new venue for future applications of meta-holograms in augmented reality, optical storage, beam multiplexing, nonlinear holography and optical manipulation." the scientists forecast.

Non-parents expand the range of their facial expressions in caring for infants among primates, a team of anthropologists has found. The study shows the ability, among non-relatives, to both decipher facial expressions and to be attuned to others' emotional states, revealing the evolutionary nature of communication.

The research, which appears in the journal Evolution, focused on the relationship between alloparenting, or infant care by non-parents, and the adoption of detailed facial expressions across more than 30 species of primates.

"Our results confirm previous work indicating that facial expressions facilitate communication between individuals living in larger social groups," says Paola Cerrito, a doctoral candidate in NYU's Department of Anthropology and College of Dentistry and an author of the paper. "But, this is the first study to demonstrate that the frequency of infant care by non-parents further predicts the ability to produce complex facial expressions across primate species."

Speaking to the larger significance of the study, Alex DeCasien, a doctoral candidate in NYU's Department of Anthropology and an author of the paper, adds, "Successful infant care by individuals other than the mother--such as the father, siblings, a babysitter, and other relatives--relies heavily on facial expressions. It is through this form of nonverbal communication that caregivers can understand the needs of infants and also coordinate care amongst themselves, thus enabling them to provide appropriate and effective infant care."

The adaptive value of facial expressions has been debated in evolutionary biology ever since Darwin's seminal work, The Expression of Emotion in Man and Other Animals (1872). It's been long established that primates, including humans, exhibit the most intricate facial displays. And while earlier scholarship has focused on the role of social interaction in the evolution of primate facial expressions, this relationship had not been verified in a wide sample of species.

In the Evolution paper, Cerrito and DeCasien studied the relationship between the frequency of alloparental care and selected orofacial brainstem nuclei--the parts of the brain that control most of the muscles from the eyes down to the neck--using existing and newly collected databases on primate behavior.

The researchers hypothesized that the frequency of infant care by individuals other than the parents predicts facial musculature dexterity--the ability to produce intricate facial expressions.

Consistent with their hypothesis, the results showed that, across the studied species, increased facial dexterity was positively correlated with the frequency of alloparental care. Notably, however, these relationships were not found with paternal care, suggesting that fathers may, similarly to mothers, rely on hormonal changes to help them become attuned to the infants' needs.

"How do adults attune themselves to the needs of slow-developing, helpless offspring?" Cerrito asks. "Mothers, across mammalian species, are hormonally primed, but what about others? Our work suggests that non-parents achieve this via facial expressions, but it appears that fathers don't. So after looking at our results, we tried to make sense of them and discovered a significant body of literature indicating that males caring for their offspring also undergo hormonal changes. Our conclusion is that they use the same adaptive strategy as mothers, only mediated by different hormones."

"Overall, this work suggests that alloparenting requires increased facial dexterity to facilitate nonverbal communication between infants and their non-parent caregivers," adds Cerrito. "Accordingly, alloparenting and complex facial expressions are likely to have co-evolved in primates."

Mercury pollution is an issue of global concern due to its toxic effects. High levels have already been measured in Arctic organisms - with worrying effects on ecosystems and the food chain. So far, the Greenland Ice Sheet has not been taken into account as a part of the Arctic mercury cycle. Now, researchers led by Jon Hawkings of the German Research Centre for Geosciences in Potsdam and Florida State University show that meltwaters in the southwest of Greenland transport considerable amounts of mercury into the Arctic Ocean. Due to the large quantities detected, the researchers assume that they are of geological origin. They present their measurements in the current issue of Nature Geoscience.

Mercury: poison for humans and the environment - especially in the Arctic

Mercury is hardly useful biologically, but proves to be all the more toxic in the form of various chemical compounds. It accumulates in the food chain and becomes a danger to humans through the consumption of fish and seafood. The socio-economic costs associated with the environmental and health impacts are estimated at more than five billion US dollars per year.

A significant aggravation of this problem is due to fossil energy production, industry, mining and transport. But there are also natural sources such as emissions from volcanoes, fire and the weathering of mercury-containing rocks. The Arctic is proving to be a particular problem zone in both respects: the mercury content in marine organisms there has increased by an order of magnitude over the past 150 years. Dust particles and aerosols enter this region via the atmosphere, and climate change and the associated warming of the Arctic lead to higher inputs through more and stronger meltwaters.

International team focuses on Greenland ice sheet

The Greenland Ice Sheet, which covers about a quarter of the Arctic land mass, has received little attention in this context so far. This has been changed by a 22-member international research team led by Jon Hawkings, postdoctoral researcher in the Interfacial Geochemistry Section at GFZ and Florida State University, with 17 participating institutions from Europe and the USA (see below). In measurement campaigns during the Arctic summers of 2012, 2015 and 2018, they took samples from three meltwater outflows from glacier catchments on the southwestern edge of the Greenland Ice Sheet and downstream fjords. The meltwater was filtered in the laboratory tent, the filtered sediment air-dried, cooled and subjected to initial analyses. Mercury levels were determined in detail in the laboratories of the participating institutions, among other things with mass and fluorescence spectrometry.

Surprisingly high mercury concentrations

Originally, Hawkings and his colleague, glaciologist Jemma Wadham, professor at the Cabot Institute for the Environment at the University of Bristol, wanted to investigate the content and pathways of nutrients in these waters. During the analysis, they were then surprised by extremely high mercury levels, comparable to rivers in industrial China: the typical level of dissolved mercury in rivers is around 1 to 10 nanograms per litre. This is equivalent to a grain-of-salt-sized amount of mercury in an Olympic-sized swimming pool of water. However, in the meltwater rivers of Greenland's glaciers, the researchers found much higher levels of more than 150 nanograms per litre. Undissolved mercury particles were found in even much higher concentrations of more than 2000 nanograms per litre.

"The export of dissolved mercury from this region must be considered globally significant," Jon Hawkings emphasises. He says it is up to 42 tons per year, which is about ten per cent of the estimated global riverine export of mercury to the oceans. "This is among the highest concentrations of dissolved mercury ever measured in natural waters. And environmentally high levels persist in downstream fjords, posing a potential risk of accumulation in coastal food webs," Hawkings said.

Climate change is likely to further aggravate the situation

This finding is particularly relevant not least against the background that fishing is Greenland's primary industry with the country being a major exporter of cold-water shrimp, halibut and cod.

"We've learned from many years of fieldwork at these sites in Western Greenland that glaciers export nutrients to the ocean, but the discovery that they may also carry potential toxins unveils a concerning dimension to how glaciers influence water quality and downstream communities, which may alter in a warming world and highlights the need for further investigation," Jemma Wadham said.

Natural source requires rethinking of conservation measures

The source of the large amounts of mercury detected is very likely the Earth itself, at the base of the ice sheet, Hawkings believes. This is suggested, among other things, by comparative data from the surface of snow and ice, where it accumulates from burning fossil fuels or another industrial source. That could be important for scientists and policymakers to plan for managing mercury pollution in the future.

"All the efforts to manage mercury thus far have come from the idea that the increasing concentrations we have been seeing across the Earth system come primarily from direct anthropogenic activity, like industry," Hawkings said. "But mercury coming from climatically sensitive environments like glaciers could be a source that is much more difficult to manage."

LAWRENCE -- For two weeks in June 2020, a massive dust plume from Saharan Africa crept westward across the Atlantic, blanketing the Caribbean and Gulf Coast states in the U.S. The dust storm was so strong, it earned the nickname "Godzilla."

Now, researchers from the University of Kansas have published a new study in the Bulletin of the American Meteorological Society parsing the mechanism that transported the dust. Their results explain a phenomenon that could occur more frequently in the years ahead due to climate change, affecting human health and transportation systems.
African dust darkened the skies of the Caribbean and American Gulf States thanks to a trio of atmospheric patterns, according to the study.

"Our study finds that it was mainly three different systems," said lead author Bing Pu, assistant professor of geography & atmospheric sciences at KU. "The African easterly jet exports the dust from Africa towards the Atlantic region. Then the North Atlantic Subtropical High, which is a high-pressure system sitting over the subtropical North Atlantic, can further transport it towards the Caribbean region. Once the dust reaches the Caribbean region, the Caribbean low-level jet -- that's another system -- along with the subtropical high can further transport the dust from Caribbean region towards the States."

Pu and co-author Qinjian Jin, lecturer and academic program associate with KU's Department of Geography & Atmospheric Science, used satellite datasets to reconstruct the patterns that transported the dust from Africa to the Americas.

"We mainly used Moderate Resolution Imaging Spectroradiometer on Terra and Aqua satellites, the Visible Infrared Imaging Radiometer Suite onboard the Suomi National Polar-orbiting Partnership satellite, and Cloud-Aerosol Lidar with Orthogonal Polarization onboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite," Pu said.

Combining the satellite data with readings from air quality stations, the researchers used computers to analyze how the dust was handed off between jet-stream systems to reach the Caribbean and U.S., where it disrupted transportation and had the potential to change weather.

"News reports mentioned the visibility of the airport in San Juan, Puerto Rico, was reduced down to five miles, which is really low," Pu said. "Visibility in the U.S. Virgin Islands was down to three miles, so it can affect public transport. There are environmental impacts as well. Dust can affect circulation and precipitation -- they can modify climate as well, when there's a large amount."

Worse, the dust plume from Africa had the potential to cause health problems for people in the Americas.

"Small particles, especially those with diameter less than 2.5 micrometers, can easily be taken into the human breathing system and cause respiratory diseases," Pu said. "Some studies have linked this back to lung cancer as well. There's also a study finding that the dust storm has been associated with increased nonaccidental and cardiovascular mortality in the United States. Also, there are dust-dwelling fungi which may cause a disease called Valley fever that happens in Arizona and California and has been related to dust storms in those regions."

Pu said hotter, drier weather and reduced vegetation in Africa could produce more airborne dust. Yet, these emissions are hard to forecast.

"There are some observations showing there is reduced precipitation in West Africa over the 20th century, which indicate drying there would have more dust emissions," she said. "But model results don't give a conclusion about whether dust will increase or decrease in the future. Some papers find that there would be decreased dust emissions. Our previous study found that there might be an increase in southern Sahara region in the summertime."

Further, according to Pu, the cooperation of jet systems needed to transport the dust across the ocean is even less predictable.

"Even if you have enhanced or decreased emission, if there aren't favorable conditions for dust to be transported, then its impact on this downwind region will be harder to quantify," she said. "In addition to understanding the emission process in the dust-source regions, we also need to look at circulation variations that help us better project this long-range transport of dust as well as its environmental and climate impacts in the U.S. Other regions can be affected as well because African dust can be transported to South America and also Europe and the Mediterranean region."

Plants contain several types of specialized light-sensitive proteins that measure light by changing shape upon light absorption. Chief among these are the phytochromes.

Phytochromes help plants detect light direction, intensity and duration; the time of day; whether it is the beginning, middle or end of a season; and even the color of light, which is important for avoiding shade from other plants. Remarkably, phytochromes also help plants detect temperature.

New research from Washington University in St. Louis helps explain how the handful of phytochromes found in every plant respond differently to light intensity and temperature, thus enabling land plants to colonize the planet many millions of years ago and allowing them to acclimate to a wide array of terrestrial environments.

The new work from the laboratory of Richard D. Vierstra, the George and Charmaine Mallinckrodt Professor of Biology in Arts & Sciences, is published this week in the Proceedings of the National Academy of Sciences (PNAS).

For the first time, these biologists fully characterized the phytochrome family from the common model plant Arabidopsis thaliana on a biochemical level.

The scientists also extended that characterization into the phytochromes of two important food crops: corn and potatoes. Instead of finding that all phytochrome isoforms are identical, they found surprising differences.

"A major hurdle toward understanding how phytochromes direct most aspects of plant growth and development has been defining how the related isoforms work collectively and uniquely to regulate specific cellular activities," Vierstra said.

Plants typically express three or more phytochromes. It was well-known that plants can respond to wide ranges of light intensities but other factors such as expression levels and signaling potential were considered as the likely culprits.

"Now we know that the differing biophysical properties of the isoforms also underpin the unique signaling potentials within the plant phytochrome photoreceptor families," Vierstra said. "These properties are evident in Phy families in plants ranging from Arabidopsis to maize and potatoes, indicating that they likely emerged very early in phytochrome evolution."

A deeper understanding of these proteins will allow scientists to use phytochromes as tools both in agriculture and for research in the field of optogenetics, which has exploited phytochromes to precisely control cellular events simply by shining light.

"It is striking how differently the two major Arabidopsis phytochromes respond to varying light levels, where low levels of light akin to heavy shade can nearly fully activate the PhyA isoform, while the PhyB isoform requires near full sun to become fully active," said Zachary Gannam, postdoctoral fellow in biology in Arts & Sciences and co-first author of the new paper.

The results also show why PhyB may have the greatest role in how plants sense temperature -- something that will become even more important in a warming world.

"A plant's struggle for survival is foreign to us. They are rooted in place and must adapt to their immediate environment or perish," said E. Sethe Burgie, research scientist in biology and co-first author of the new paper.

"Graded responses to light are important to keep plant growth under appropriate control as the plant adapts to its environment," he continued. "They're likely integral for detecting waxing or waning daylight hours to allow flowering and setting seed in the proper season."

In coming months, the researchers plan to modify and grow plants that manifest different variations and combinations of the phytochromes included in this laboratory study, with the goal of modifying light and temperature sensation of crops for agricultural benefit.

Invasive alien plants are plant species that grow in an environment outside their native habitat. If they successfully establish self-sustaining populations in these new environments - an event called "naturalization" - they can have considerable negative impacts on local ecosystems, economies, and societies. But not all alien plant species are equally effective in invading new habitats. Therefore, an international team of scientists, headed by Konstanz-based biologist Professor Mark van Kleunen, investigated different types of "invasiveness" and possible factors that determine invasion success of alien plants in Europe.

The new study, published in PNAS, describes plant species invasiveness using three distinct dimensions: local abundance, geographic extent, and habitat breadth. In the current study, these dimensions were assessed at a continental scale for large proportions of the alien and native European floras. High values in the variables characterise the most successful invaders. Introduction histories play an important role in performance along the three dimensions, as do some biological traits: Early introduction to Europe, non-European origin, and rapid growth are characteristics common to many "super-invaders". The findings of the study improve our general understanding of how plant species - invasive and native ones - distribute and may help to better predict and manage future plant invasions.

Are all invasive alien plants the same?

Experts in the field of ecology increasingly acknowledge that the term "invasive" does not describe a single property. Instead, there are different characteristics in a species' distribution that can characterize it as invasive or not. To learn more about the different ways that a plant can become invasive, the authors of the recent study combined two extensive datasets, the Global Naturalized Alien Flora (GloNAF) database and the European Vegetation Archive (EVA). For the analysis of the combined data, they adopted a three-dimensional framework that had previously been used to describe the "rarity" of native plant species.

The first description of this framework by Deborah Rabinowitz dates back to the 1980s. Rabinowitz put forward the idea that a "common" plant species is one that is locally very abundant, occurs over a large area, and populates many different habitats. Besides this form of absolute "commonness", there are seven forms of rarity as different combinations of low performances along the three dimensions. For example, a "rare" plant species can have a high local abundance, but is restricted to a small area and grows only in a specific habitat type.

Just as the model of Rabinowitz allows for different forms of rarity in native plants, it opens up the possibility of various types of "invasiveness" when applied to alien species. Considering this possibility is important because different types of alien invasive species may require different management strategies to deal with them. "If an alien species begins to dominate a local plant community but has low potential to expand its geographic extent and is specialised to a certain type of habitat, conservation efforts could be focused on controlling the species locally rather than preventing further spread," Dr Trevor Fristoe, lead author of the current study, gives an example.

Alien, but not so different

For native plant species, scientists have previously discovered that the three dimensions of commonness are not completely independent of each other. Instead, species that are locally abundant often also tend to be geographically widespread and occupy a wide range of habitats. "For the alien plant species, our expectation was that these dimensions should be linked just like they are in native distributions. After all, alien plants at one location are native plants somewhere else," Fristoe describes an important assumption of the study.

Indeed, the scientists found the associations between the three dimensions - local abundance, geographic extent, and habitat breadth - in the alien species that have invaded Europe to be very similar to the pattern of associations they found in the native European flora: Plants that are successful in one dimension also tend to be successful in the other ones. "These parallels suggest that the same bio-geographic and ecological mechanisms are shaping the distribution in native and alien plant species," Fristoe concludes.

Drivers of invasion success

Despite the similarities in the association patterns between native and invasive plants, there is also a decisive difference between the two groups: Different from native plant species, the invasive species did not evolve in the invaded habitats into which they have only recently been introduced. Instead, they evolved in other parts of Europe or even on other continents. "Regardless of whether general associations between the dimensions of invasiveness exist, we wanted to identify the drivers of success in each of the dimensions. The plants' introduction histories were one aspect we considered, along with more ecological or biological factors," Fristoe explains the second objective of the study.

The scientists found that plants that excel in all three dimensions tend to come from other continents, such as Asia or the Americas, while plants introduced from other parts of Europe are generally poor invaders. In addition, the super-invaders from outside of Europe often have biological properties that help them grow rapidly - at the price of weaker defence mechanisms. Taken together, this provides support for a hypothesis called "enemy release hypothesis". "The general idea of the 'enemy release hypothesis' is that invasive species leave behind many of the pathogens, herbivores, and competing species they co-evolved with in their native habitats when invading new environments. This allows them to 'grow out of control' and the effect may be more pronounced when continental boundaries, such as oceans or mountain ranges, have been crossed for invasion," Fristoe elaborates the idea.

Exceptions to the rule

The scientists also found exceptions to the pattern that plants that are successful in one dimension are also successful in the others and identified possible reasons for these exceptions. For example, the more recent its date of introduction to its new environments, the more likely an invasive plant deviates from the rule. „They are new. They still need time to balance out the conditions," Fristoe provides an explanation for this observation and continues: "This is quite important. If you find an invasive plant that is successful in only one of the dimensions, but also new, there is reason to worry: It might become successful in the other dimensions later on." Thus, the "dimensions of invasiveness" framework is not only a valuable tool for explaining current patterns of naturalization and improving our understanding of the dynamics of species distribution in general. It can also help to anticipate future invasions and to develop tailored management strategies to better control invasive alien plant species.

A mathematical model which can predict landslides that occur unexpectantly has been developed by two University of Melbourne scientists, with colleagues from GroundProbe-Orica and the University of Florence.

Professors Antoinette Tordesillas and Robin Batterham led the work over five years to develop and test the model SSSAFE (Spatiotemporal Slope Stability Analytics for Failure Estimation), which analyses slope stability over time to predict where and when a landslide or avalanche is likely to occur.

In a study published in Scientific Reports, the research team was able to predict landslides, which often cause severe disruption, economic damage and deaths, of various sizes and speeds and in different environments.

"The key to the success of this model is that it works across a vast range of spatial or temporal scales and is informed by the physics of failure in soil and rock bodies," said Professor Tordesillas.

"It can be used at a mine, where millimetre precision measurements of surface motion of a rock face are made every few minutes. And it can also be used in a rural area, where the only available data is a satellite radar image taken every few days to weeks."

The SSSAFE model was initially developed for mine monitoring, where landslides are a constant threat, but using publicly available satellite data, the team was able to retrospectively predict the 2017 Xinmo landslide, which buried a township in China.

"For Xinmo, the model highlighted significant movement at what became the rock avalanche source, 10 months before the disaster occurred," said Professor Tordesillas. "If we can use this model, along with freely available satellite data to recognise potential future landslide sites well before they happen, actions can be taken to protect communities, saving many lives."

With SSSAFE exploiting big data analytics, network science and physics, Professor Tordesillas hopes her research will be used by industry and governments worldwide to help early warning systems (EWS) in mitigating landslide hazards in the face of climate change.

"Very few studies have used remote sensing data to detect precursors of slope failure. Crucially, little is known about how to interpret this data from known physics of granular failure to better understand and predict events leading to catastrophic landslides. We achieved both in SSSAFE," she said.

Bottom Line: In a new recommendation statement, the U.S. Preventive Services Task Force (USPSTF) recommends that clinicians offer pregnant adolescents and adults effective behavioral counseling interventions aimed at promoting healthy weight gain and preventing excess gestational weight gain in pregnancy. Excess weight at the beginning of pregnancy and excess gestational weight gain have been associated with adverse maternal and infant health outcomes such as a large for gestational age infant, cesarean delivery or preterm birth. The USPSTF routinely makes recommendations about the effectiveness of preventive care services.

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

(doi:10.1001/jama.2021.6949)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Note: More information about the U.S. Preventive Services Task Force, its process, and its recommendations can be found on the newsroom page of its website.

In a study funded by National Institute for Health Research (NIHR) Maudsley Biomedical Research Centre (BRC) researchers examined whether depression, either before or during pregnancy, affects the mother-infant relationship. The research was published today (Tuesday 25 May) in BJPsych Open.

Researchers looked at the quality of mother-infant interactions eight weeks and 12 months after birth in three groups of women; healthy women, women with clinically-significant depression in pregnancy, and women with a lifetime history of depression but healthy pregnancies.

The study used a sample of 131 women: 51 healthy mothers with no current or past depression, 52 mothers with depression referred to the South London and Maudsley NHS Foundation Trust Perinatal Psychiatry Services, and 28 'history-only' mothers with a history of depression but no current diagnosis.

Quality of interaction

At both eight weeks and 12 months, mothers and babies in the depression and history-only groups displayed a reduced quality of interaction. Specifically, at eight weeks, 62% in the group of mothers with depression during pregnancy and 56% in the group of mothers with a history-only of depression scored in the lowest category of relationship quality, where therapeutic interventions are recommended, compared with 37% in the healthy group. All mother and baby groups improved in their quality of interaction between 8 weeks and 12 months which researchers say indicates that with time all mothers and their babies can become more attuned to each other.

At six days, new-born babies of mothers in the depression and history-only groups had decreased social-interactive behaviour, which, together with maternal socio-economic difficulties, was also predictive of a reduced quality of interaction, while postnatal depression was not.

Dr Rebecca Bind, lead author and Research Associate at Institute of Psychiatry, Psychology & Neuroscience, King's College London, says: "Our findings suggest that perinatal mental health professionals should offer support not only to women with depression during pregnancy, but also to pregnant women with a history of depression, as they may also be at risk of interaction difficulties. Future research should try to understand why a history of depression, despite a healthy perinatal period, may impact the developing relationship."

Senior author Carmine Pariante, Professor of Biological Psychiatry at the Institute of Psychiatry, Psychology & Neuroscience, King's College London and Consultant Perinatal Psychiatrist at the South London and Maudsley NHS Foundation Trust, said:

"We recommend that healthcare professionals provide pregnant women at risk of interaction difficulties with examples of positive caregiving behaviours, and with ways to engage their babies and understand their needs, all of which could be incorporated into parenting and birth classes and health visits. We also suggest that interventions that can help the mother-infant interaction should be made more widely available, such as video feedback, where a clinician and mother discuss what behaviours work best to engage and comfort the baby, and structured mother-baby activities, such as art and singing groups. This is especially important because we know that the early years are vital for future mental health and wellbeing."

The relationship between mothers and infants was assessed using the Crittenden Child-Adult Relationship Experimental-Index which assesses 'dyadic synchrony', a term that describes the quality of the relationship as a whole. Researchers analysed films of three-minute interactions filmed at eight weeks and 12 months postnatal. Mothers played with their babies while researchers scored the relationship based on seven aspects of behaviour: facial expression, vocal expression, position and body contact, affection and arousal, turn-taking contingencies, control, and choice of activity. The researchers are grateful to the women and their infants who participated in the PRAM-D study and to everyone on the study team who recruited, collected, and analysed data.