Earth

Japan -- Of all the exciting topics in the field of material and biochemical research, one of the hottest by far is unraveling the mysteries of spider silk.

Often claimed to be 'stronger than steel', the protein-based fibers have the potential to change the material world as we know it. However, despite decades of research, nobody has been able to mass produce spider silk, primarily because the exact method of how it's made is still shrouded in mystery.

In a step toward understanding its inner workings, researchers at Kyoto University's Graduate School of Engineering report on a new model for spider silk assembly, reporting that the key to spider silk 'spinning' is a combination of acidification and a process known as liquid-liquid phase separation, or LLPS.

"Spider silk is made of proteins called spidroins. The spider has a gland that is densely filled with spidroins in its liquid state called dope," explains Ali D Malay first author of the study, published in Science Advances.

"This liquid is rapidly converted into the tough and structurally complex silk. To investigate how exactly this is done we decided to go back to the drawing board and look at spidroins itself. So we developed artificial spidroins that closely mimic the ones found in nature."

Developing the protein was no easy task, but they landed on using a specific spidroins called MaSp2, one of the more common spider silk proteins, and that are water soluble.

After isolating their artificial spider silk protein, the team began observing its activity under different chemical conditions, intending to understand what key chemical changes are needed for the liquid phase to turn solid.

"We first saw the the protein gathering into small clusters. But when we added potassium phosphate it instantly began to condense into big high-density droplets," explains Malay. "This is a phenomenon known as liquid-liquid phase separation -- it happens quite often in cells -- and it's when liquid droplets change their size and density according to the surrounding environment."

But this was only one part of the puzzle. What does it take to make this liquid phase into the silk fibers we know so well? The key was pH. As the team lowered the pH of the solution, the globs began to fuse together, forming a fine network of fibers.

Both LLPS and fiber network formation happened so spontaneously that it was visible in real time. Moreover, when the fiber network was placed under mechanical stress it began to organize itself into a hierarchical structure just like spider silk.

"Spider silk often surpasses the most advanced manmade materials today, and making these synthetic fibers often rely on harmful organic solvents and high temperatures. What's incredible here is that we were able to form spider silk using water as solvent, and at ambient temperatures," concludes Keiji Numata who led the study.

"If we can learn to emulate the mechanisms of spider silk spinning, it could have a profound impact on the future of manufacturing."

Tree rings, with their special characteristics of precise dating, annual resolution, long time series and climate sensitivity, have been widely considered a useful proxy for past climate variations.

Researchers at the Institute of Botany of the Chinese Academy of Sciences have given an overview on using tree rings to identify climate regime shifts in a perspective paper entitled "Tree rings circle an abrupt shift in climate," which was published in Science on Nov. 26.

In the paper, Prof. ZHANG Qi-Bin and Dr. FANG Ouya provided background in the field and discussed its advances. They also referenced a paper reporting a recent climate regime shift to a hotter and drier climate over inner East Asia, which was written by lead author ZHANG Peng from South Korea and published in the same issue of Science.

"Careful attention is required when using tree rings to reconstruct a specific climate variable over a large geographical region," said Prof. ZHANG Qi-Bin. "Signals from the macroclimate must be extracted efficiently while removing the nonclimate noise embedded in the tree rings."

Changes in climate have dramatic effects on natural ecosystems and human society. Less well understood is whether these changes are irreversible beyond a certain tipping point, that is, whether they represent a climate regime shift.

Scientists worldwide are alarmed about the potential risks of abrupt climate changes and their impacts on ecosystems and society, yet it is still difficult to identify the exact occurrence of climate regime shifts.

To judge whether climate systems undergo regime shifts from one steady state to another, scientists must understand the natural range of climate variability over a time scale that is much longer than the new regime.

ZHANG Peng et al. compiled tree-ring width data from 76 sites throughout inner East Asia and successfully screened 20 sites with strong signals of summer heatwave frequency and soil moisture content.

They found that the magnitude of the warm and dry anomalies compounding in the past two decades is unprecedented over the past 260 years. They further illustrated that the heatwaves and droughts became tightly coupled, which is likely caused by a pronounced enhancement of land-atmosphere coupling along with anthropogenic climate change.

However, it is still challenging for scientists to disentangle the interaction of climate variables and clarify whether these interactions generate negative or positive feedbacks, according to Prof. ZHANG Qi-Bin and Dr. FANG.

Furthermore, spatial differences related to climate regime shifts are worthy of study.

Using tree-ring data as a proxy for past climate variability and forest dynamics, Prof. ZHANG Qi-Bin's lab has long been engaged in investigating the responses of tree growth to multiple dimensions of climate change and ecological disturbances, and in exploring spatial and temporal patterns of forest health.

Using barcodes to label and identify everyday items is as familiar as a trip to the supermarket. Imagine shrinking those barcodes a million times, from millimetre to nanometre scale, so that they could be used inside living cells to label, identify and track the building blocks of life or, blended into inks to prevent counterfeiting. This is the frontier of nanoengineering, requiring fabrication and controlled manipulation of nanostructures at atomic level - new, fundamental research, published in Nature Communications, shows the possibilities and opportunities ahead.

The University of Technology Sydney (UTS) led collaboration developed a nanocrystal growth method that controls the growth direction, producing programmable atomic thin layers, arbitrary barcoded nanorods, with morphology uniformity. The result is millions of different kinds of nanobarcodes that can form a "library" for future nanoscale sensing applications.

The researchers anticipate that such barcode structures will attract broad interests in a range of applications as information nanocarriers for bio-nanotechnology, life sciences, data storage, once they are incorporated into a variety of matrixes.

Lead author Dr Shihui Wen said the research provides a benchmark that will open up the potential for engineering smaller nanophotonics devices.

"The inorganic nanobarcode structures are rigid, and it is easy to control the composite, thickness and distance accuracy between different functional segments for geometrical barcoding beyond the optical diffraction limit . Because they are chemically and optically stable, the nanoscopic barcodes can be used as carriers for drug delivery and tracking into the cell, once the surface of the barcode structures is further modified and functionalized with probe molecules and cargos," Dr Wen, from the UTS Institute of Biomedical Materials and Devices (IBMD), said.

The team also had an additional breakthrough with the development of a novel, tandem decoding system, using super-resolution nanoscopy to characterize different optical barcodes within the diffraction limit.

Senior author, UTS IBMD Director, Professor Dayong Jin said there was no commercial system available for this type of super resolution imaging.

"We had to build the instrumentation to diagnose the sophisticated functions that can be intentionally built into the tiny nanorod. These together allow us to unlock the further potential for placing atomic molecules where we want them so we can continue to miniaturise devices. This was the first time we were able to use super resolution system to probe, activate and readout the specific functional segment within the nanorod.

"Imagine a tiny device, smaller than one thousandth the width of a human hair, and we can selectively activate a particular region of that device, see the optical properties, quantify them. This is the science now showing many new possibilities," he said. Professor Jin is also the co-director of UTS-SUStech Joint Research Centre.

The researchers envisage the developed nanoscale optical devices could be simultaneously used for tagging different cellular species.

"These devices are also readily applicable for high-security-level anticounterfeiting when different batches of them are blended with inks and can be readily printed on high-value products for authentication.' Dr Wen said

The UK has is facing an uphill battle if it is to meet its ambitious target of halving maternal mortality by 2030 against a backdrop of increased social inequalities, increasing maternal age and obesity together with a rising number of caesarean sections, all contributory risk factors for maternal morbidity and mortality.

The complex issues around maternal deaths will be presented in a new review by an anaesthesiologist who works on the UK Confidential Enquiry into Maternal Deaths (CEMD), which began in 1952 and investigates the death of every mother during pregnancy and after childbirth.

During his presentation at Euroanaesthesia (the annual meeting of the European Society of Anaesthesiology and Intensive Care [EASIC]) Dr James Bamber, of Cambridge University Hospitals NHS Foundation Trust, and based at Addenbrooke's Hospital, Cambridge, UK, will highlight that during the past sixty years of the Enquiry the proportion of maternal deaths directly due to pregnancy and delivery has fallen.

The most recent published statistics (for 2015-17) showed that the UK has a maternal mortality rate of 9.1 deaths per 100,000 women per year which has changed little from a similar rate thirty years ago (1985-87) when it was 9.8 deaths per 100,000. The maternal mortality rate has fluctuated over the intervening years.

"A greater proportion of women now die from underlying health conditions aggravated by pregnancy such as heart disease which is now the most common cause of maternal death. The most common direct obstetric cause of maternal death is thromboembolism (blood clots)," explains Dr Bamber.

In 1952/54, 78% of maternal deaths were due to direct (obstetric) causes, in 1985/87 62% of maternal deaths were due to direct causes. In 2015/17 35% of maternal deaths were due to direct causes - the 'cross-over' occurred in 1994/96 when 50% of maternal deaths were due to direct causes.

"The UKEMD ensures every maternal death has a detailed in-depth review by multidisciplinary assessors so that lessons for care can be identified and recommendations made to improve maternity care of all women including those outside the UK," explains Dr Bamber.

Examples of these recommendations include promoting the use of guidelines to manage women with severe pre-eclampsia in pregnancy. Since the publication and widespread adoption of national guidelines there has been a significant decrease in the number of deaths and mortality rate for women with this condition. "The Enquiry will have contributed to this reduction in maternity deaths and morbidity due to health professionals implementing the recommendations made in its reports," says Dr Bamber.

The Enquiry process was reformed in 2011 after a government review which resulted in an academic consortium, with MBRRACE-UK* based at Oxford University being awarded the contract to run the Enquiry every year rather than every three years previously. This has made the process more agile to respond to any new health crisis such as SARS-CoV-2 and a rapid report was published in August 2020 examining the deaths of ten women with COVID-19.

Dr Bamber concludes: "Despite these improvements in maternity care, the overall rate of maternal deaths in the UK has remained unchanged over the past 30 years. This is against a backdrop of rising maternal social inequalities, increasing maternal obesity, increasing maternal age and rising caesarean section rates, all risk factors for maternal death and morbidity. The UK Government has set a challenging ambition to reduce maternal mortality by 50% by 2030. This challenge means the Enquiry process will be as important now as at any time since 1952."

Researchers at ETH Zurich have identified a self-?regulating mechanism in European deciduous trees that limits their growing-?season length: Trees that photosynthesise more in spring and summer lose their leaves earlier in autumn.

Leaves of temperate deciduous trees glow in all their yellow and red glory just before falling, signalling that autumn has come. This process, called leaf senescence, allows trees to prepare for the coming winter by suspending their growth and extracting nutrients from the foliage. In the trees' phenological cycle, leaf senescence marks the end of the productive period during which they absorb CO2 through photosynthesis.

Global warming has resulted in longer vegetation periods in recent years, with spring leaf emergence in European trees happening about two weeks earlier than 100 years ago and autumn senescence about six days later. It is generally expected that senescence will continue to be delayed in a warming climate, increasing the amount of carbon captured by these plants under climate change.

However, researchers at ETH Zurich have now come to the opposite conclusion. In a study published in the journal Science, they have demonstrated a self-regulating mechanism that limits the productive period. Increased photosynthesis in spring and summer leads to earlier senescence, which could result in earlier leaf fall in autumn.

Sink limitation as senescence driver

"Accurate forecasts of the growing season of trees have previously been difficult, as the drivers of leaf senescence have not been well understood," says Constantin Zohner, study leader and senior scientist at ETH Zurich's Crowther Lab.

Until now, scientists have generally assumed that, after the summer ends, the autumnal declines in temperature and day length are the main cues determining the timing of leaf senescence. Some studies additionally indicated that leaf emergence in spring has an effect on leaf death in autumn. "But because the importance of these mechanisms remained unclear, phenological models were at best only partly able to take such effects into account," says the biologist.

Zohner suspected that the link between spring and autumn phenology can be explained by photosynthetic activity - or more precisely, the phenomenon of carbon sink limitation. In this hypothesis, scarce soil nutrients such as nitrogen, among other things, limit the quantity of CO2 that a plant can absorb during the season. The more carbon trees absorb in spring and sumer, the earlier leaf senescence should therefore begin.

This role of photosynthesis in the control of leaf senescence has long been known for example in crops, but has never been tested in trees. This is what motivated ETH Zurich researchers to investigate the drivers of autumn phenology with a combined approach of field observations, laboratory tests and modelling.

Strong effect of photosynthesis

Long-?term observations of six European deciduous tree species over the last six decades formed the basis of the study. Using this data, Zohner's team tested the relative influence of various factors on the timing of autumn senescence, including leaf emergence in spring, seasonal photosynthesis, CO2 concentration, temperature and precipitation.

In addition, the researchers also performed a set of experiments with saplings in climate chambers and outdoors. This enabled them to isolate the effects of temperature, daylight and CO2 content that drive the correlation between photosynthesis and leaf senescence.

The long-?term observations revealed a strong effect of photosynthesis: in years with increased photosynthesis in spring and summer, leaf senescence began earlier, with each ten percent increase in photosynthetic activity advancing leaf senescence by eight days. The experiments supported these findings.

A new autumn senescence model

"Our analyses suggest that seasonal photosynthesis, autumn temperatures and day length are the key drivers of senescence," says lead author Deborah Zani in explaining the forces involved. "Several other factors, such as atmospheric CO2 concentrations, summer temperatures, light levels and precipitation also appear to influence senescence, but only indirectly through affecting photosynthesis."

Warmer autumns under climate change therefore tend to postpone senescence. This effect, however, is counteracted by increasing photosynthesis in spring and summer through rising CO2 concentrations, warmer summer periods and earlier leaf emergence.

Zani and Zohner developed a new model of autumn phenology that takes all factors into account according to their relevant weight. This model enabled the researchers to predict the timing of autumn senescence over the last six decades with up to 42 percent more accuracy compared to previous models.

The authors then used this model to generate updated forecasts of leaf senescence timing over the rest of the century and the results were quite unexpected. Until now it had been expected that senescence would occur two to three weeks later by the end of the century. "Our new model suggests the contrary: if photosynthesis continues to increase, leaves will senesce three to six days earlier than they do today" says Zani. "This means that the growing season will be extended by only 8 to 12 days by the end of the century, around two to three times less than we previously thought", Zani adds. She conducted the data analysis and modelling as part of her Master's thesis at the Crowther Lab.

Impact on carbon balance

In their study, the researchers made use of data from the Pan European Phenology Project, evaluating a total of 434,000 phenological observations at 3,800 locations in central Europe between 1948 and 2015. Six representative species were studied: European horse chestnut, silver birch, European beech, European larch, English oak and rowan.

The authors see their study as evidence that temperate forests have a limited capacity to absorb CO2: "Seasonal CO2 uptake will probably increase to a lesser degree with rising temperatures than older models predicted," says Zohner. The ETH Zurich researchers now want to better understand carbon sink limitation in the forests of the earth.

After the scientists of the Borexino experiment succeeded in detecting neutrinos from the sun's proton-proton chain in 2014, they now could also measure neutrinos from the sun's second fusion process, the Carbon Nitrogen Oxygen cycle (CNO cycle).

This means that all of the theoretical predictions on how energy is generated within the sun have now also been experimentally verified. The findings are the result of years of efforts devoted to bringing the background sources in the energy range of the CNO neutrinos under control.

The sun generates its energy through the fusion of hydrogen to helium. This occurs in two ways: The majority of the energy, approximately 99 percent, comes from a process of fusion and decay which begins with two hydrogen nuclei and ends with one helium nucleus. This process is referred to as the pp (proton-proton) chain.

The rest of the energy results from a cycle in which a total of four hydrogen nuclei ultimately combine to form a helium nucleus with the help of carbon, nitrogen and oxygen as catalysts and intermediate products. In stars larger than our sun the majority of energy generated is generated by this second process, referred to as the CNO process because of the involvement of carbon, nitrogen and oxygen.

Proof for the fusion cycle postulated in the 1930s

This second cycle was postulated as another source of the sun's energy in the 1930s by physicists Hans Bethe and Carl Friedrich von Weizsäcker independently of one another, but could not be experimentally confirmed until now.

Physicists working on the Borexino Experiment in the underground laboratory deep below the Italian Gran Sasso massif have now succeeded for the first time in proving the presence of this cycle based on the neutrinos it produces.

Several years ago the Borexino Experiment team presented for the first time an overall investigation of the fusion processes of the pp chain using its neutrinos. Scientists from the physics department of the Technical University of Munich (TUM) were centrally involved both measurement processes.

Interference obscured the signal until now

Because of their energy distribution, the neutrinos of the CNO cycle were difficult to distinguish from those generated by the radioactive decay of tiny traces of other elements. Primarily bismuth-210 from trace impurities on the surface of the detector wall were responsible for concealing the signals of the CNO cycle.

Due to convection movements, these contaminants got into the detector liquid. In order to eliminate the disturbance, the convection inside the Borexino detector had to be brought to a standstill, which was technically extremely elaborate.

"For a long time I thought it would never be possible to successfully make this measurement," says Stefan Schoenert, Professor for Experimental Astroparticle Physics at TU Munich. "But six years of hard work have paid off and now we've proven the presence of the CNO neutrino signal for the first time."

New evidence on the metallicity of the sun

These results confirm not only the theoretical predictions on the sun's two fusion processes, they also provide evidence regarding the metallicity of the sun, i.e. the concentration levels of nuclei which are heavier than hydrogen and helium.

Different astrophysical investigative methods have generated differing results in past years. "The new Borexino results now support observations with higher metallicity values," says Prof. Lothar Oberauer of TUM.

This is particularly important in the context of the fundamental properties of stars such as their size, temperature, brightness and lifetime, which are determined by the degree of metallicity. Understanding the chemical composition of the sun is therefore essential to understanding the properties of all stars.

Non-indigenous or alien species need to be appreciated for their potential benefits and not just the negative impacts they can have on the environment, according to new research.

In recent decades, there have been numerous examples of non-indigenous species (NIS) establishing a foothold and then causing harm in new environments. Meanwhile, others have had benefits for fisheries or replaced lost ecological functions.

Stopping the spread of such species is virtually impossible, so a new study - led by the University of Plymouth and the Marine and Environmental Research (MER) Lab in Cyprus - is calling for a complete rethink of how they are considered in the future.

Focused on the Mediterranean, the most 'invaded' sea on Earth, the research highlights species - including lionfish, clams, barracuda, rabbitfish and jellyfish - that have become resident in the region as a result of factors such as the changing climate or human introduction.

To try and address such issues, the study proposes a cost-benefit analysis which will guide whether NIS should be managed in a sustainable or unsustainable way.

Where non-indigenous species are known to have positive effects on the environment and marine economies, a series of policy reforms are proposed.

However, where there are no perceived benefits, it proposes legislation to actively promote commercial over-fishing and the creation of radical NIS-specific licences for recreational fishers. One example of such a species is the lionfish (Pterois miles), first seen in the Mediterranean Sea in 2012 but now thriving and well-established across southern Europe and having a marked impact on other native species and the wider environment.

The study also recommends investment in the market and valorisation of NIS products, the development of novel products, and fishery-related tourism.

It also highlights the importance of investing in natural-based solutions such as the protection of native predators, the enhancement of marine protected areas (MPAs), and allowing SCUBA divers to remove invasive species from MPAs.

The application of the proposed reforms would turn NIS into a source of income and nutrition, and adhere to United Nations Sustainable Development Goal 14, which calls for the conservation and sustainable use of the oceans, seas, and marine resources for sustainable development.

The researchers behind the study are among the collaborators on the four-year, €1.6million RELIONMED project - funded by the European Union - which aims to assess the history of the lionfish invasion in Cyprus, and identify ways to minimise its future impact.

Periklis Kleitou, Research Assistant on the RELIONMED project and lead author on the study, said: "The Mediterranean is heavily over-exploited. But it is unwise to perceive all the effects of non-indigenous species in the region as negative. Some species have been established in the basin for decades playing a major role in ecosystem and fisheries balance. In some parts of the eastern Mediterranean, they might account for over half the fishery catches in some areas, but the solutions we propose would create an ecosystem-based framework to promote fishery sustainability in the region."

Co-author Dr Sian Rees, Associate Professor of Social-Ecological Systems at the University of Plymouth, added: "Transformative ocean management demands that we think beyond our current norms and challenge dominant narratives. This research connects - for the first time - the roles that non-indigenous species play in driving down levels of biodiversity and at the same time providing opportunities for fishing (food production). What we are proposing is a new governance perspective that firmly links fisheries management with conservation and investment strategies. This research is set to change how NIS are managed in the Mediterranean and provide long term benefit for society."

Water sustains life on earth. The first life originated in an ancient sea, and since then, nearly every species that has existed in the past or lives today depends on the exact balance of salt and water (~145 mM; called body-fluid homeostasis or salt homeostasis) for survival. Humans can go weeks without food but will not last more than a few days without water, stressing the importance of this liquid.

The human body has several intricate mechanisms to make sure we consume an appropriate amount of water for maintaining the homeostasis, which is requisite to survival. One of these simple but key "hacks," is thirst. When the body experiences dehydration on a hot day (noted by the excess of sodium in the body compared to water, a condition called hypernatremia), the brain sends "signals" to the rest of the body, making us crave the tall glass of water. On the other hand, under a condition called hyponatremia, where there is a more water than sodium, we suppress water drinking. The neural mechanisms of how this happens are a subject of great interest.

A team of researchers from Tokyo Institute of Technology, headed by Prof Masaharu Noda, have conducted extensive research into this. In their previous studies, they identified that thirst is driven by the so-called "water neurons" in the subfornical organ (SFO) of the brain, a region just outside the blood-brain barrier. When the body is dehydrated, the plasma levels of a peptide hormone called angiotensin II increase. These levels are detected by special angiotensin II "receptors" of water neurons to stimulate water intake. In turn, under sodium-depleted conditions (where there is more water than sodium), the activity of these water neurons is suppressed by "GABAergic" interneurons. "The latter control appeared to be dependent on the hormone cholecystokinin (CCK) in the SFO. However, the CCK-mediated neural mechanisms underlying the inhibitory control of water intake had not been elucidated so far," states Prof Noda.

Now, in their latest study published in Nature Communications, the researchers find out more details about this mechanism. They performed an array of experiments including transgenic mice studies, single cell dynamics, fluorescence microscopic Ca2+ imaging, and optical and chemogenetic silencing to explore the neurons in the SFO.

They made several interesting observations: first, CCK was produced in the SFO itself, by CCK-producing excitatory neurons, which activate the GABAergic interneurons through their "CCK-B" receptors, causing them to suppress the water neurons and inhibit thirst. What's more, there are two distinct subpopulations of these CCK neurons. Group 1, which is the largest population, shows strong and sustained activation under the Na-depleted condition (excessive water in the body). Group 2 shows a more rapid and transient activation in response to water intake, with the activation lasting no longer than 20 seconds. There are hints of a third group as well, but these neurons don't show activation in either condition.

Prof Noda is excited about the implications of this study. "Since CCK has long been noted for being a gastrointestinal hormone, these findings open up many possibilities, the most exciting one being the probability of a negative feedback control of drinking based on water sensing signals from the oropharynx or gastrointestinal tract," he reports.

The research highlights the roles of CCK in both Group 1 blood-mediated "persistent" and Group 2 oropharyngeal/gastrointestinal "transient" suppression of water intake. The potential of CCK to activate CCK-B receptor-positive different GABAergic interneurons in a cell-type specific manner underlies the mechanism for the functioning of neuronal circuits. Overall, this research has furthered the understanding of the "thirst control" phenomenon substantially.

Mongolia's semi-arid plateau may soon become as barren as parts of the American Southwest due to a "vicious cycle" of heatwaves -- that exacerbates soil drying, and ultimately produces more heatwaves -- according to an international group of climate scientists.

Writing in the journal Science, the researchers warn that heatwaves and concurrent droughts have increased significantly during the past two decades, with troubling implications for the future. Using tree-ring data, which offer a glimpse of regional climates from before modern weather logs, the researchers developed heatwave and soil moisture records that suggest recent consecutive years of record high temperatures and droughts are unprecedented in more than 250 years.

According to the study's findings, the record high temperatures in the region are accelerated by soil drying, and together these changes are magnifying the decline of soil water. "The result," coauthor Deliang Chen at Sweden's University of Gothenburg said, "is more heatwaves, which means more soil water losses, which means more heatwaves -- and where this might end, we cannot say."

When soil is wet, evaporation cools air at the surface. However, when soil no longer has any moisture, heat transfers directly to the air. In their paper, Abrupt shift to hotter and drier climate over inner East Asia beyond the tipping point, the authors state that in the past 260 years, only recent decades "show significant anticorrelation between heatwave frequency and soil moisture, alongside a radical decline in soil moisture fluctuation." The scientists note that a series of recent heatwaves in Europe and North America reveal the connection with near-surface air and soil moisture and suggest that "the semi-arid climate of this region has entered a new regime in which soil moisture no longer mitigates anomalously high air temperature."

Already, lakes in the Mongolian Plateau have experienced rapid reductions. As of 2014, researchers from China had documented a 26 percent decrease in the number of lakes greater than one square kilometer in size, with even larger average reductions in size for the region's largest lakes.

"Now we are seeing that it isn't just large bodies of water that are disappearing," said corresponding author Jee-Hoon Jeong of Chonnam National University in South Korea. "The water in the soil is vanishing, too."

"This may be devastating for the region's ecosystem which is critical for the large herbivores, like wild sheep, antelope and camels," Peng Zhang, the study's lead author and a researcher at the University of Gothenburg. "These amazing animals already live on the edge, and these impacts of climate change may push them over."

Coauthor Jin-Ho Yoon, of the Gwangju Institute of Science and Technology in South Korea, noted that the hundreds of years of tree-ring data make it clear that the confluence of increased summer heatwaves and severe droughts are unique in the context of the past 260 years. Coauthor Hans Linderholm, from the University of Gothenburg, said the trees used in the analysis appear to "feel" the heatwaves throughout their lifetimes.

"The conifer trees respond strongly to anomalously high temperatures," Linderholm said. "By examining their growth rings, we can see their response to the recent heatwaves, and we can see that they do not appear to have experienced anything like this in their very long lives."

Tree rings examined in the study were mainly collected from the Mongolian Plateau, which suggests that the increasing heat is affecting plants even at high elevations.

Daniel Griffin, of the University of Minnesota's Department of Geography, Environment and Society, who is not involved in this study but has reviewed the paper, said that long-term perspective from these tree-ring records illustrates a nuanced picture of the changing climate that is now afflicting large swaths of the inner East Asia region.

"It is one thing to recognize that the "normal" climate conditions are changing. However, what concerns me the most is thinking about the extreme events of the future: how severe might those become?" asked Griffin. "And if the "new normal" is extremely hot and dry by historical standards, then future extremes may well be unlike anything previously witnessed."

While warmer and drier trends are observed over Europe and Asia, Mongolia and its surrounding countries are particularly interesting to climate scientists because this Inner East Asia region has a very direct link to global atmospheric circulations.

"Summer atmospheric waves tend to create a high-pressure ridge pattern around Mongolia that can persist for weeks, triggering heatwaves," explained coauthor Simon Wang of Utah State University in the United States. "The warming climate is amplifying these atmospheric waves, increasing the chance of prolonged or intensified high-pressure to occur over Mongolia and this can also have ramifications across the Northern hemisphere."

"Such large-scale atmospheric force is further amplified by local interactions with the land surface," coauthor Hyungjun Kim, from the University of Tokyo in Japan, pointed out. "An even worse problem may have already occurred in which an irreversible feedback loop is triggered and is accelerating the region toward a hotter and drier future."

Indeed, the researchers have observed that recent heatwaves have come with even drier and hotter air, under the strengthened high-pressure ridge, than the heatwaves of the past.

The research team found that the warming and drying concurrence seems to approach a "tipping point" and is potentially irreversible, which may push Mongolia into a permanent state of aridness.

Over the past 40,000 years, ice sheets thousands of kilometres apart have influenced one another through sea level changes, according to research published today in Nature. New modelling of ice sheet changes during the most recent glacial cycle by a McGill-led team offers a clearer idea of the mechanisms that drive change than had previously existed and explains newly available geological records. The study demonstrates, for the first time, that during this period, changes in the Antarctic ice sheet were driven by the melting ice sheets in the Northern Hemisphere.

As the climate cooled, during the last Ice Age, water became locked up in land ice in the Northern Hemisphere leading to dropping sea levels in Antarctica and consequent growth of the ice sheet. As the climate warmed, on the other hand, as it did through the period of deglaciation, the retreating ice in the Northern Hemisphere led to rising water levels around Antarctica, which in turn drove a retreat of the Antarctic ice sheet.

"Ice sheets can influence each other over great distances due to the water that flows between them," explains senior author Natalya Gomez, from McGill's Department of Earth and Planetary Sciences. "It's as though they were talking to one another through sea level changes."

Finding answers in ocean sediment and records of past shorelines

"Polar ice sheets are not just large, static mounds of ice. They evolve on various different time scales and are in constant flux, with the ice growing and retreating depending on the climate and the surrounding water levels," explains Gomez. "They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs."

In order to investigate the mechanisms involved in driving changes in the Antarctic ice sheet over geologic time scales, the study draws on numerical modeling and a wide range of geological records, from cores of sediment from the ocean bottom near Antarctica to records of land exposure and past shorelines.

With this information, the researchers were able, for the first time, to simulate, simultaneously, changes in both sea levels and ice dynamics in both hemispheres over the past 40,000 years. This time frame provides the basis for a broad understanding of how climate factors affect ice sheets, since it covers the period leading up to the peak of last Ice Age, between 26,000-20,000 years ago up to the present.

Water and ice sheets on the move

The records suggest that there the ice loss from the Antarctic ice sheet over this period was significant, with intermittent periods of accelerated retreat. The researchers found that the only mechanism that could explain this response were the sea level changes in Antarctica caused by changes to the ice sheets in the Northern Hemisphere.

"We found a very variable signal of ice-mass loss over the last 20,000 years, left behind by icebergs breaking off Antarctica and melting down in the surrounding oceans," says Michael Weber, from the Department of Geochemistry and Petrology at the University of Bonn. "This evidence could hardly be reconciled with existing models until we accounted for how the ice sheets in both hemispheres interact with one another across the globe."

"The scale and complexity of ice sheets and the oceans, and the secrets of the Earth's past climate that are locked up in the geological record are fascinating and inspiring," concludes Gomez. "Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another. In the modern era, we haven't seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of changes in Earth's history can inform us about this."

The deep seas - vast expanses of water and seabed hidden more than 200 metres below the ocean surface to depths up to 11,000 metres - are recognised globally as an important frontier of science and discovery.

But despite the fact they account for around 60% of Earth's surface area, large areas remain completely unexplored, yet the habitats they support impact on the health of the entire planet.

Now an international team of scientists, spanning 45 institutions in 17 countries, has called for a dedicated decade-long programme of research to greatly advance discovery in these remote regions.

The programme - which scientists have named Challenger 150 - will coincide with the United Nations Decade of Ocean Science for Sustainable Development, which runs from 2021-2030.

Challenger 150 will generate new geological, physical, biogeochemical, and biological data through a global cooperative of science and innovation, including the application of new technology. These data will be used to understand how changes in the deep sea impact the wider ocean and life on the planet.

Among its key areas of focus are to build greater capacity and diversity in the scientific community, acknowledging the fact that existing deep-sea research is conducted primarily by developed nations with access to resources and infrastructure.

The programme will use this new knowledge of the deep to support regional, national, and international decision-making on deep-sea issues such as mining, hydrocarbon extraction, fishing, climate mitigation, laying of fibre optic cables and conservation.

The international team presented the rationale behind the call for action in a comment article in Nature Ecology and Evolution, simultaneously publishing a detailed blueprint of how the actions can be best achieved in Frontiers in Marine Science.

Led by members of the Deep-Ocean Stewardship Initiative (DOSI) and the Scientific Committee on Oceanic Research (SCOR), the authorship reflects both the gender and geographical diversity such a programme demands, with authors from the six inhabited continents of the world.

They note that the UN Decade provides an unrivalled opportunity to unite the international science community to deliver a giant leap in our knowledge of the deep seas.

Kerry Howell, Professor of Deep-Sea Ecology at the University of Plymouth (UK) and lead author of the research publications, said: "The deep seas and seabed are increasingly being used by society, and they are seen as a potential future asset for the resources they possess. But managing these resources sustainably requires that we first understand deep-sea ecosystems and their role in our planet, its people and its atmosphere. Our vision is for a 10 year programme of science and discovery that is global in scale and targeted towards proving the science to inform decisions around deep-ocean use. We believe the United Nations Decade of Ocean Science provides the perfect opportunity to achieve that."

Dr Ana Hilario, Researcher at the University of Aveiro (Portugal) and co-lead of the DOSI and SCOR Decade working groups, added: "The Decade also provides the opportunity to build a long-term programme for training and capacity building in ocean sciences. With Challenger 150, we aim to train the next generation of deep-sea biologists and focus on training scientists from developing countries, but also early stage scientists from all nations. Such training will create a network of enhanced capacity that will allow countries to exercise their full role in international discussions on the use of ocean resources within and outside of their national boundaries."

Comments from other authors

Professor Alex Rogers, Science Director at the philanthropic organisation REV Ocean (Norway): "The deep ocean is planet Earth's inner space. In many ways it is as challenging to investigate as the moon or Mars and like them we have much to learn about the deep sea. Although the deep ocean seems remote it is an important part of the Earth system and stores more carbon than any other component, including both the atmosphere and terrestrial ecosystems. It is also now visibly impacted by human activities including deep-sea fishing, marine plastic pollution and climate change. It is now critically important we learn more about the deep sea so it can be managed more sustainably."

Professor Kerry Sink, Principal scientist at the South African National Biodiversity Institute and Research Associate at Nelson Mandela University (South Africa), noted the significant and timeous opportunities provided by the UN Decade of Ocean Science to meet global, regional and national goals: "Co-designed and co-delivered transdisciplinary science across geographies is the transformative action we need for the deep sea. This will equip current and future generations with the capacity, knowledge and relationships for more equitable ocean benefits."

Dr Paul Snelgrove, Network Director of the Canadian Heathy Oceans Network, Associate Scientific Director of the Ocean Frontier Institute, and University Research Professor in Ocean Sciences and Biology at Memorial University of Newfoundland (Canada): "The vast size and complexity of Earth's largest ecosystem by far, the deep sea, requires working together internationally in order to make significant headway in 'scratching below the surface' of this critical component of our planet's life support system."

Dr Anna Metaxas, Professor of Biological Oceanography at Dalhousie University (Canada): "We need a global effort of this magnitude to preserve the services that the deep ocean provides and ensure equitable and sustainable use of the resources found beneath the surface."

Professor Agnes Muthumbi, Professor of Marine Biology, University of Nairobi (Kenya): "The ocean holds a wealth of diversity that is disappearing even before it is documented especially in the developing countries. The situation is worse for the deep sea where exploration and extraction of resources is going on without proper environment impact assessment being carried out. The UN Decade of Ocean Science offers the opportunity to discover this biological diversity and establish a mechanism to conserve it."

Professor Nadine Le Bris, Professor at Sorbonne University (France): "Deep-sea ecosystems are already affected by climate change. Any conservation or protection measure therefore needs to be supported by novel monitoring strategies to understand the strong interactions of deep sea species with the mosaics of habitats on the ocean floor."

Dr Paulo Sumida, Professor of Biological Oceanography at the University of São Paulo (Brazil): "The deep sea is one of the major repositories of species diversity and carbon in the globe, cycling huge amounts of materials and the distribution of heat, which keeps Earth habitable. The programme will put the deep sea in the spotlight and help to foster a new generation of scientists."

Dr Javier Sellanes López, of the Universidad Católica del Norte (Chile): "Everybody is aware that global biodiversity is under a severe threat, but the knowledge we have for the degree of impacts in the different environments is unbalanced, and much scarcer for marine habitats than for terrestrial ones, and particularly critical for the deep sea. Besides, for a series of reasons - including remoteness, logistic issues, and the economic wealth of nations facing certain oceanic areas - information on marine ecosystems is also unproportioned in terms of geographic coverage. In particular, the south-eastern Pacific is among the most vast, most remote, and poorly explored corners of our oceans, and initiatives like the present one give us an unprecedented opportunity to start taking care of this debt."

Professor Elva Escobar, research scientist from the Institute of Marine Sciences and Limnology at the Universidad Nacional Autónoma de Mexico (UNAM) (Mexico): "This is a once in a lifetime opportunity to be able to contribute to a 10-year programme of science and discovery providing the science we need to inform decisions around deep-ocean use."

Professor Christopher German MBE, Senior Scientist from Woods Hole Oceanographic Institution (USA): "The deep ocean represents one of the last unexplored and untapped frontiers on Earth. Our deep oceans represent the largest habitat for life on Earth, but also remain the least understood. To sustainably manage this important food and mineral resource, we need to massively expand our ability to explore and understand. Just like the original Challenger Expedition in its day, this effort will demand new innovation and implementation of previously only dreamed-of tools. Pushing the limits of our technology to expand our knowledge will make us better stewards of our home planet."

Dr Maria Baker, Senior Researcher at the University of Southampton (UK) is excited at the prospect of Challenger 150 as a way to continue the momentum generated during the Census of Marine Life programme (1990-2000): "This highly successful programme opened new channels of communication that helped to lay the foundations for global collaborative studies of ocean life. Embarking on a new decadal programme to explore our deep-ocean ecosystems and their critical functions and services, whilst increasing diversity in our deep-ocean science community is essential. Crucially, this programme aims to help generate deep-sea expertise in nations where it is currently lacking and for many more nations to directly contribute robust science advice to inform sustainable management of our ocean for the future."

Professor Bhavani Narayanaswamy, from the Scottish Association for Marine Science: "The deep sea is by far the largest ecosystem on planet earth with a plethora of species and a variety of different habitats. A truly global programme is required in order to not only learn more about this ecosystem and to put measures in place to manage it in a sustainable fashion, but to also train the next generation of researchers, the future custodians of the deep sea."

Dr David Bailey, Senior Lecturer at the University of Glasgow: The deep ocean is subject to many threats, including new industries such as deep-sea mining, and the ongoing impacts of fishing. Deep habitats and species are often highly vulnerable, but because they are not visible to most people they have never had the attention they need. I am proud to be associated with this vision for a future programme of research and education. I believe it will uncover many secrets of the deep ocean, bring them to a wide audience, and inspire the protection needed."

The Challenger 150 programme

The years 2022-2026 mark the 150th anniversary of the voyage of HMS Challenger. This ship left the UK in 1876 on a 4 year mission, circumnavigating the globe, mapping the seafloor, recording the global ocean temperature, and providing a first panoramic view of life in the deep seas.

The Challenger Deep - the deepest known point of the ocean - is named after it, as were a number of vessels in NASA's space programmes. However, whereas the original HMS Challenger crew was all-white and all-male, the Challenger 150 programme aims to harness its scientific sense of discovery through a modern-day, inclusive and representative spirit of collaboration.

Endorsed by the authors of the current studies, more information about Challenger 150 is available at https://challenger150.world.

To see how deeply interconnected the planet truly is look no further than the massive ice sheets on the Northern Hemisphere and South Pole.

Thousands of kilometers apart, they are hardly next-door neighbors, but according to new research from a team of international scientists -- led by alumna Natalya Gomez Ph.D.'14, and including Harvard professor Jerry X. Mitrovica -- what happens in one region has a surprisingly direct and outsized effect on the other, in terms of ice expanding or melting.

The analysis, published in Nature, shows for the first time that changes in the Antarctic ice sheet were caused by the melting of ice sheets in the Northern Hemisphere. The influence was driven by sea-level changes caused by the melting ice in the north during the past 40,000 years. Understanding how this works can help climate scientists grasp future changes and instability as global warming increases the melting of major ice sheets and ice caps, researchers said.

The study models how this seesaw effect works. They found that when ice on the Northern Hemisphere stayed frozen during the last peak of the Ice Age, about 20,000 to 26,000 years ago, it led to reduced sea-levels in Antarctica and a growth of the ice sheet there. When the climate warmed after that peak, the ice sheets in the north started melting, causing sea-levels in the southern hemisphere to rise. This rising ocean triggered the ice in Antarctica to retreat quickly to about the size it is today over thousands of years.

The question of what caused the Antarctic ice sheet to melt so rapidly during this warming period has been a long-standing enigma.

"That's the really exciting part of this," said Mitrovica, the Frank Baird Jr. Professor of Science in the Department of Earth and Planetary Sciences. "What was driving these dramatic events in which the Antarctic released huge amounts of ice mass? This research shows that the events weren't ultimately driven by anything local. They were driven by sea level rising locally but in response to the melting of ice sheets very far away. The study establishes an underappreciated connection between the stability of the Antarctic ice sheet and significant periods of melting in the Northern Hemisphere."

The retreat was consistent with the pattern of sea level change predicted by Gomez, now an assistant professor of earth and planetary sciences at McGill University, and colleagues in earlier work on the Antarctic continent. The next step is expanding the study to see where else ice retreat in one location drives retreat in another. That can provide insight on ice sheet stability at other times in the history and perhaps the future.

"Looking to the past can really help us to understand how ice sheets and sea levels work," Gomez said. "It gives us a better appreciation of how the whole Earth system works."

Along with Gomez and Mitrovica, the team of scientists on the project included researchers from Oregon State University and the University of Bonn in Germany. They combined ice-sheet and sea-level modeling with sediment core samples from the ocean bottom near Antarctica to verify their findings. The rocks they focused on, called ice-rafted debris, were once embedded inside the Antarctic ice sheet. Fallen icebergs carried them into the Southern Ocean In analysis, researchers tried to determine when and where they were released from the ice sheet. They also looked at markers of past shorelines to see how the ice sheet's edge has retreated.

Gomez has been researching ice sheets since she was a GSAS student in the Mitrovica Group. She led a study in 2010 that showed that gravitational effects of ice sheets are so strong that when ice sheets melt, the expected sea level rise from all that meltwater entering the oceans would be counterbalanced in nearby areas. Gomez showed that if all of the ice in the West Antarctic ice sheet melted, it could actually lower sea level near the ice by as much as 300 feet, but that sea level would rise significantly more than expected in the Northern Hemisphere.

This paper furthered that study by asking how melting ice sheets in one part of the climate system affected another. In this case, the researchers looked at the ice sheets in the Northern Hemisphere that once covered North America and Northern Europe.

By putting together modeling data on sea-level rise and ice-sheet melting with the debris left over from icebergs that broke off Antarctica during the Ice Age, the researchers simulated how sea-level and ice dynamics changed in both hemispheres over the past 40,000 years.

The researchers were able to explain several periods of instability during the past 20,000 years when the Antarctic ice sheet went through phases of rapid melting known as "meltwater pulses." In fact, according to their model, if not for these periods of rapid retreat the Antarctic ice sheet, which covers almost 14 million square kilometers and weighs about 26 million gigatons, would be even more of a behemoth than it is now.

With the geological records, which were collected primarily by Michael Webster from the University of Bonn, the researchers confirmed the timeline predicted by their model and saw that this sea-level change in Antarctica and the mass shedding corresponded with episodes of melting of ice sheets in the Northern Hemisphere.

The data caught Gomez by surprise. More than anything though, it deepened her curiosity in these frozen systems.

"These ice sheets are really dynamic, exciting, and intriguing parts of the Earth's climate system. It's staggering to think of ice that is several kilometers thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences," Gomez said. "It's just motivation for trying to better understand these really massive systems that are so far away from us."

Researchers in Japan have revealed a previously unknown mechanism for pain control involving a newly identified group of cells in the spinal cord, offering a potential target for enhancing the therapeutic effect of drugs for chronic pain.

While neurons may be the most well-known cells of the central nervous system, an assortment of non-neuronal cells first discovered in the mid-nineteenth century also play a wide variety of important roles.

Originally named after the Greek word for "glue," these glial cells are now known to be much more than glue and in fact are critical elements for regulating neuronal development and function in the central nervous system.

Among the different types of glial cells, astrocytes are the most abundant in the central nervous system, but, unlike neurons in different brain regions, researchers still have yet to develop a detailed understanding of groupings of astrocytes with distinct properties.

Now, researchers led by Makoto Tsuda, professor at Kyushu University's Graduate School of Pharmaceutical Sciences, have discovered a unique population of spinal cord astrocytes with a role in producing pain hypersensitivity.

Found in the outer two layers of gray matter near the back of the spinal cord--a location referred to as the superficial laminae of the spinal dorsal horn--the astrocytes are in a region known to carry general sensory information such as pressure, pain, and heat from around the body to the brain.

Using mice, the researchers showed that stimulating noradrenergic (NAergic) neurons--so called for their use of noradrenaline as a neurotransmitter--that carry signals from the locus coeruleus (LC) in the brain down to the spinal dorsal horn activates the astrocytes and that the astrocyte activation results in pain hypersensitivity.

These observations overturn the prevailing view that descending LC-NAergic neurons suppress pain transmission in the spinal dorsal horn.

"The discovery of this new population of astrocytes reveals a new role of descending LC-NAergic neurons in facilitating spinal pain transmission," explains Tsuda.

Considering these findings, suppressing signaling of these astrocytes by noradrenaline may enhance the effect of drugs for chronic pain.

To initially test this, the researchers genetically engineered mice in which response of astrocytes to noradrenaline was selectively inhibited and gave them duloxetine, an analgesic drug thought to increase levels of noradrenaline in the spinal cord by preventing uptake by descending LC-NAergic neurons.

Indeed, the modified mice exhibited an enhanced easing of chronic pain by duloxetine, further supporting the researchers' proposed role of the astrocytes.

"Although we still need more studies with different drugs, this astrocyte population appears to be a very promising target for enhancing the therapeutic potential of drugs for chronic pain," says Tsuda.

In JST Strategic Basic Research Programs, Drs. Masato Hirano and Shinichi Furuya, Sony Computer Science Laboratories, Inc., discovered a training method to further improve the delicate touch of pianists.

Experts such as pianists, athletes and surgeons acquire advanced skills through tremendous amounts of practice. It is difficult to further improve upon these skills, and the methods for exceeding these limits have not been clarified.

The research group developed a system that freely controls the weight of piano keys using a haptic device, which enables to control the strength and direction of the force. This same group has also invented active haptic training (AHT) that enhances tactile force sense during exercise by presenting the tasks of discriminating the difference in piano key weights and the correctness of answers. Three experiments were conducted using AHT in 64 pianists and 25 ordinary persons who had received no professional music training. The results showed that enhancing the somatosensory function of fingertips with AHT could improve the accuracy of keystrokes, breaking through the ceiling effect of over-trained skills. Such skill improvement was not observed through usual repetitive practice, or in ordinary persons with no piano experience.

This study demonstrated that, in order to exceed the limits in the exercise skills of experts, it was important to optimize the method rather than increase the amount of training. This finding is expected to be useful for elucidating principles of the nervous system that define the limits in exercise skills, new training theories to exceed the limits of experts' expertise, and functional flexibility (plasticity) of the expert's brain, as well as in the development of rehabilitation methods for neurological disorders in which finger functions were impaired due to excessive training.

Over the years, the efficiency of PSCs has increased at an unprecedented pace. However, many reports have revealed significant irreversible decomposition of the organic component under high humidity and high temperature conditions, implying the instability of organic-inorganic hybrid perovskite solar cell in real applications. Normally, inorganic materials exhibit better stability compared to organic materials, especially at elevated temperatures. However, the size of the Cs+ cation is too small to hold the PbI62? octahedron. Therefore, the photoactive α-phase (cubic phase) is unstable and the CsPbBrI2 and CsPbI3 materials easily convert to the undesired δ-phase (orthorhombic phase) at room temperature. In addition, a main limiting factor in the photoelectric performance of all-inorganic PSCs is the energy loss (a large Eloss ca. 0.7 to 0.9 eV). In brief, a large Eloss reflects inhomogeneous energy landscape, large trap density and significant energy disorder in the device, which generate a nonradiative energy loss channel and a Voc reduction. Therefore, enhancing the Voc to reduce Eloss is crucial for high performance in all-inorganic PSCs.

Generally, Voc is related to the band gap of perovskite, the highest occupied molecular orbital (HOMO) of the hole-transporting layer (HTL) and the lowest unoccupied molecular orbital (LUMO) of the electron-transporting layer (ETL). Meanwhile, the Voc of devices is also related to the quality of film (grain size). Such as, Kim et al. analyzed an intensity-dependent Voc on the basis of Shockley-Read-Hall (SRH) model and confirmed that decrease in grain size is accompanied by a downturn in optoelectronic performance of PSCs, due to the increase in trap density.

In this work, we demonstrate a secondary grain growth functionalization with ammonium oxalate ((NH4)2C2O4* H2O) to improve the optoelectronic performance of all-inorganic PSCs, wherein (NH4)2C2O4* H2O can effectively promote the secondary growth of the perovskite crystal to a few microns. The resulting high-quality perovskite film exhibited higher carrier mobility and lower trap density and eventually achieved ultra-low energy loss (0.64 eV). The CsPbBrI2:(NH4)2C2O4* H2O-based device exhibits a highest Voc of 1.24 V and PCE of 16.55% under AM 1.5 G, and a record PCE is 28.48% under under a fluorescent lamp of 1000 lux.