Earth

Children and adolescents who speak more than one language may reach adulthood with more grey matter, according to a new study.

In a paper published in Brain Structure and Function, an international team of academics led by the University of Reading and Georgetown University looked at detailed scans of children's and adolescents' brains and found that bilingual participants had potential advantages of both grey and white matter than similarly-aged children who spoke only one language.

While bilingualism has previously been shown to positively affect brain structure and cognitive performance in adults, the paper is the most comprehensive analysis to date showing that the effect of speaking more than one language may have similar impacts on developing brains.

Dr Christos Pliatsikas, the leader of the project and an Associate Professor of Psycholinguistics in Bi and Multilinguals at the University of Reading said:

"Grey matter in the brain decreases from an early age, but our study found that key brain areas showed less such shrinkage in bilinguals than monolinguals during development."

"In previous studies, we've already seen that bilingualism has a positive effect on grey and white matter in adult brains, but this is the first time we've seen strong evidence for these effects in children and adolescents as well."

Dr Michael Ullman, senior author on the paper and Professor of Neuroscience at Georgetown University Medical Center, said:

"It may be the case that the effects on the brain that we have seen in adult bilinguals have their roots in childhood. We will be looking more at this in future studies."

More grey matter

The brain scans showed that the loss in grey matter that children and adolescents experience during development was less pronounced in bilinguals than those who only spoke one language.

Grey matter refers to the portions of the brain where the bodies of brain cells are found, such as around the surface of the brain (called the cortex). White matter refers to parts of the brain containing the connections between brain cells, allowing them to communicate (the connections are white because they are insulated with fat).

The study found that that the bilinguals kept more grey matter during brain development, and also increased white matter, suggesting more efficient brain communication. In both cases the effects were found mainly in brain areas linked to language learning and use.

Dr Christos Pliatsikas said:

"This is an important study for two reasons. The first is that by looking at the brains of children and adolescents, we can start to see how and when bilingualism has an effect on the brain during language development. While we've previously looked at differences between bilingual and monolingual adult brains at static points, here we see the effect of bilingualism on the brain as we develop."

"Second, the impact of bilingualism on grey and white matter may have a number of wider benefits for language and cognitive function, such as performance in tasks related to attention and executive control, which have been suggested to be enhanced in older bilinguals. Overall, the findings indicate that encouraging bilingualism in childhood may have benefits later in life."

Climate change is a topic of broad concern, with everyone wondering how the climate will change in the future. However, since climate change is a slow process, it is hard to study based on short-term observations, and hence using climate models has become the most common method employed by the scientific community.

A climate model is a set of software running on a super computer that can solve the physical formulations that describe the variations in atmosphere, ocean, etc. via numerical algorithms, thus helping us to study climate changes. In recent decades, climate models have developed from simple models to complex systems, and their performances keep on improving worldwide. But what about the performance of autonomous climate models developed in China?

The climate system model FGOALS-f3-L, developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP/CAS), is one of the latest Chinese climate models, and is currently participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6). Evaluations of the experimental outputs show that the model is able to reasonably simulate the climatic elements in historical experiments, including the long-term trends and climatological patterns. Besides, significant improvements are apparent compared with the previous version. For the simulated ocean and sea ice, the most obvious biases are cold biases and overestimation of sea ice in the Arctic.

According to Prof. Yongqiang Yu, the corresponding author of this recently published study in Advances in Atmospheric Sciences, "the obvious improvements of this latest model in simulating the climate system are meaningful for us to study climate dynamics and enhance our ability to project climate change, and of course make new contributions to the development of autonomous climate models in China."

The observational study involving more than 1,300 people was led by the London School of Hygiene & Tropical Medicine (LSHTM), University of Malawi College of Medicine and colleagues at the University of Cambridge.

It found most patients admitted to hospital knew their HIV status, and that 90% were taking antiretroviral therapy.

However, approximately one-third of patients established on HIV treatment had significant levels of HIV in their blood, and more than 80% of these patients had resistance to two or more of their HIV antiretroviral drugs.

Patients with multidrug resistant HIV were 70% more likely to die within two months of being admitted to hospital than those without drug resistance.

This is the first study reporting such data in hospitalised patients, as access to HIV drug resistance testing is not widely available in high HIV burden African settings.

Dr Ankur Gupta-Wright from LSHTM and project lead said: "There has been an unprecedented scale-up of antiretroviral therapy in high-HIV prevalence settings in sub-Saharan Africa. However, HIV remains a common cause of admission to hospital, with a high risk of death. Our results show drug resistance is an important cause."

Distinguishing HIV drug resistance from alternative explanations for progressive illness whilst taking antiretroviral (HIV) treatment, such as patients not sticking to required dosage or stopping treatment altogether, is not usually possible. Patients who develop advanced HIV while established on ART often go undetected.

Most available data on HIV drug resistance come from outpatient clinics, where failing HIV treatment is much less common. However, hospitalised patients represent a key target group for intensified interventions, given their relatively high risks of treatment failure, advanced immunosuppression, and high short-term mortality.

This study was based on patients living with HIV who were admitted to hospital in Zomba, southern Malawi. Samples were collected at the time of hospital admission to test for the amount of HIV virus in the blood, to see if patients were responding to their HIV antiretroviral medication.

By sequencing the virus and looking for mutations, patients with high levels of HIV in their blood were tested for resistance to HIV drugs. After two months, the team compared whether patients failing ART and/or with HIV drug resistance were more likely to die.

Of 237 patients with HIV drug resistance results available, 195 (82%) had resistance to lamivudine, 128 (54%) to tenofovir, and 219 (92%) to efavirenz (all first-line drugs used to treat HIV at the time of the study).

Dr Gupta-Wright said: "These are worrying results. ART changes and saves lives, but drug resistance is threatening this progress. Timely diagnosis and management of ART failure and drug resistance in this patient population could improve individual patient outcomes and contribute to the UNAIDS 95-95-95 targets set for 2030. Rapid HIV-1 viral load tests for hospital inpatients need to be implemented, so results are available quickly and patients can be switched to alterative antiretroviral therapy.

"This could potentially save the lives of many patients living with HIV on treatment who are admitted to hospital."

Professor Ravi Gupta, from Cambridge University and senior author on the study said: ''These important findings highlight the threat posed by drug resistant HIV and call for rapid tests for drug resistant virus that could aid in determining treatments and interventions for patients in hospital.''

The authors acknowledge limitations of this study including the introduction of a new antiretroviral drug in Malawi last year called Dolutegravir, which may overcome some of the resistance found in this study.

The study was funded by the Joint Global Health Trials Scheme of the Medical Research Council, UK Department for International Development, and Wellcome Trust.

Cat owners fall into five categories in terms of their attitudes to their pets' roaming and hunting, according to a new study.

University of Exeter researchers surveyed UK cat owners and found they ranged from "conscientious caretakers" concerned about cats' impact on wildlife and who feel some responsibility, to "freedom defenders" who opposed restrictions on cat behaviour altogether.

"Concerned protectors" focussed on cat safety, "tolerant guardians" disliked their cats hunting but tended to accept it, and "laissez-faire landlords" were largely unaware of any issues around cats roaming and hunting.

Conservation organisations have long been concerned about the numbers of animals caught by the UK's large population of domestic cats.

Most pet cats kill very few wild animals, if any, but with a population of around 10 million cats, the numbers of birds, small mammals and reptiles taken can accumulate.

Apart from their role as "mousers", most owners find the dead animals brought home an unpleasant reminder of their pet's wilder side.

Addressing this problem has been difficult because of disagreements between people prioritising cat welfare and those focusing on wildlife conservation.

The Exeter team's ongoing research project "Cats, Cat Owners and Wildlife" aims to find a conservation win-win, by identifying ways of owners managing their cats that benefit the cats as well as reducing wildlife killing.

This research is a step towards understanding how cat owners view their cats and how best to manage them.

The researchers say their findings demonstrate the need for diverse management strategies that reflect the differing perspectives of cat owners.

"Although we found a range of views, most UK cat owners valued outdoor access for their cats and opposed the idea of keeping them inside to prevent hunting," said lead author Dr Sarah Crowley, of the University of Exeter's Environment and Sustainability Institute in Cornwall.

"Cat confinement policies are therefore unlikely to find support among owners in the UK.

"However, only one of the owner types viewed hunting as a positive, suggesting the rest might be interested in reducing it by some means.

"To be most effective, efforts to reduce hunting must be compatible with owners' diverse circumstances."

Suggested measures to reduce hunting success include fitting cats with brightly coloured "BirdsBeSafe" collar covers. Many owners also fit their cats with bells.

The research team are now examining the effectiveness of these and other new measures and how owners feel about them, with a view to offering different solutions.

"This latest research we have funded reveals the incredibly diverse perspectives amongst cat owners in regard to their pets' hunting behaviour," said Tom Streeter, Chairman of SongBird Survival.

"If nature is to 'win' and endangered species thrive, a pragmatic approach is needed whereby cat owners' views are considered as part of wider conservation strategies.

"The study highlights the urgent need for cat owners and conservationists to work together to find tailored solutions that are cheap, easy to implement, and have a positive effect on wildlife and bird populations across the UK."

iCatCare's Head of Cat Advocacy, Dr Sarah Ellis, said: "The finding that many UK cat owners actually care a great deal about wildlife conservation and their cats' impact on it, suggests that some owners are receptive to employing cat-friendly ways of reducing hunting.

"The right interventions could improve wildlife conservation efforts, maintain good cat mental-wellbeing, and at the same time improve the cat-human relationship.

"This would be especially true for 'tolerant guardians' and 'conscientious caretakers', by reducing the internal conflict of loving an animal that often hunts other animals they also care about."

The study included 56 cat owners, some from rural parts of the UK (mostly in south-west England) and some from urban areas (Bristol and Manchester).

The paper, published in the journal Frontiers in Ecology and the Environment, is entitled: "Diverse perspectives of cat owners indicate barriers to and opportunities for managing cat predation of wildlife."

Alongside the detailed research survey, the researchers have created a simple quiz so cat owners can find out which category bests describes them.

Many relatives who experience severe long-term grief reactions after bereavement have more frequent contact with their general practitioner already prior to bereavement, as well as a higher consumption of antidepressants and sedatives than those who have fewer critical symptoms of grief over time. This suggests that it may be possible to prevent this by catching this group earlier. This is shown by a new research result from Aarhus University.

Each year, 55,000 die in Denmark, many of them following the course of a disease. The majority of these bereavements have an effect on several close relatives. A research project from Aarhus University has now examined both the consumption of medicine and contact to general practitioners (GP) among this group of relatives.

Mette Kjærgaard Nielsen from the Department of Public Health is behind the study.

"We can see that there's a group of relatives who have increased contact with their own GP before the bereavement. Measured by symptoms of grief, such as intense longing and yearning, preoccupation with the loss and a lack of acceptance, these are the ones who find the situation hardest to deal with. This group also has a higher consumption of medicine. This means that during the course of the patient's illness, we already have contact to a group of relatives who appear to be severely psychologically affected," she explains.

Relatives should be traced earlier

The results have just been published in the British Journal of General Practice.

Relatives' grief symptoms were measured before the patient's death, and then six months and three years after the bereavement. In total, 1447 relatives, which is 83 per cent of all those involved in the study, contacted their GP. Among relatives with a constant high level of grief symptoms, even more (92 per cent) had contact with general practice, and this group had a higher consumption of antidepressants and sedatives than the relatives with a constant low level of grief symptoms.

This means that healthcare professionals have contact to - and thus the opportunity to identify - relatives who have a need for support already early in the process.

"It's relevant to follow up on the role of general practice in the case of relatives with a high level of grief symptoms or other psychological strain. There is a need for new studies to show how a preventive effort can be best used to help these relatives," says Mette Kjærgaard Nielsen.

Background for the results

The study is a population-based cohort study of relatives in Denmark. A total of 1735 relatives of patients with a terminal illness have replied to the questionnaire. All of the patients received drug reimbursement terminal subsidy due to the incurable nature of their disease and an expected short life expectancy. The relatives replied to the questionnaire while the terminal subsidy was being received, and then six months and three years after the death of the patient.

Toronto/Armidale, September 1, 2020 - How do you weigh a long-extinct dinosaur? A couple of ways, as it turns out, neither of which involve actual weighing -- but according to a new study, different approaches still yield strikingly similar results.

New research published September 1 in the prestigious journal Biological Reviews involved a review of dinosaur body mass estimation techniques carried out over more than a century.

The findings should give us some confidence that we are building an accurate picture of these prehistoric animals, says study leader Dr. Nicolás Campione -- particularly our knowledge of the more massive dinosaurs that have no correlates in the modern world.

"Body size, in particular body mass, determines almost at all aspects of an animal's life, including their diet, reproduction, and locomotion," said Dr. Campione, a member of the University of New England's Palaeoscience Research Centre.

"If we know that we have a good estimate of a dinosaur's body mass, then we have a firm foundation from which to study and understand their life retrospectively."

Estimating the mass of a dinosaur like the emblematic Tyrannosaurus rex is no small feat -- it is a creature that took its last breath some 66 million years ago and, for the most part, only its bones remain today. It is a challenge that has taxed the ingenuity of palaeobiologists for more than a century. Scientific estimates of the mass of the biggest land predator of all time have differed substantially, ranging from about three tonnes to over 18 tonnes.

The research team led by Dr. Campione compiled and reviewed an extensive database of dinosaur body mass estimates reaching back to 1905, to assess whether different approaches for calculating dinosaur mass were clarifying or complicating the science.

Although a range of different methods to estimating body mass have been tried over the years, they all come down to two fundamental approaches. Scientists have either measured and scaled bones in living animals, such as the circumference of the arm (humerus) and leg (femur) bones, and compared them to dinosaurs; or they have calculated the volume of three-dimensional reconstructions that approximate what the animal may have looked like in real life. Debate over which method is 'better' has raged in the literature.

The researchers found that once scaling and reconstruction methods are compared en masse, most estimates agree. Apparent differences are the exception, not the rule.

"In fact, the two approaches are more complementary than antagonistic," Dr. Campione said.

The bone scaling method, which relies on relationships obtained directly from living animals of known body mass, provides a measure of accuracy, but often of low precision; whereas reconstructions that consider the whole skeleton provide precision, but of unknown accuracy. This is because reconstructions depend on our own subjective ideas about what extinct animals looked like, which have changed appreciably over time.

"There will always be uncertainty around our understanding of long-extinct animals, and their weight is always going to be a source of it," said Dr. David Evans, Temerty Chair of Vertebrate Palaeontology at the Royal Ontario Museum in Toronto, senior author on the new paper. "Our new study suggests we are getting better at weighing dinosaurs, and it paves the way for more realistic dinosaur body mass estimation in the future."

The researchers recommend that future work seeking to estimate the sizes of Mesozoic dinosaurs, and other extinct animals, need to better-integrate the scaling and reconstruction approaches to reap their benefits.

Drs. Campione and Evans suggest that an adult T. rex would have weighed approximately seven tonnes -- an estimate that is consistent across reconstruction and limb bone scaling approaches alike. But the research emphasizes the inaccuracy of such single values and the importance of incorporating uncertainty in mass estimates, not least because dinosaurs, like humans, did not come in one neat package. Such uncertainties suggest an average minimum weight of five tonnes and a maximum average weight of 10 tonnes for the 'king' of dinosaurs.

"It is only through the combined use of these methods and through understanding their limits and uncertainties that we can begin to reveal the lives of these, and other, long-extinct animals," Dr Campione said.

The Sun is our star and has a profound influence on our planet, life, and civilization. By studying the magnetism on the Sun, we can understand its influence on Earth and minimize damage of satellites and technological infrastructure. The GREGOR telescope allows scientists to resolve details as small as 50 km on the Sun, which is a tiny fraction of the solar diameter of 1.4 million km. This is as if one saw a needle on a soccer field perfectly sharp from a distance of one kilometer.

"This was a very exciting, but also extremely challenging project. In only one year we completely redesigned the optics, mechanics, and electronics to achieve the best possible image quality." said Dr. Lucia Kleint, who led the project and the German solar telescopes on Tenerife. A major technical breakthrough was achieved by the project team in March this year, during the lockdown, when they were stranded at the observatory and set up the optical laboratory from the ground up. Unfortunately, snow storms prevented solar observations. When Spain reopened in July, the team immediately flew back and obtained the highest resolution images of the Sun ever taken by a European telescope.

Prof. Dr. Svetlana Berdyugina, professor at the Albert-Ludwig University of Freiburg and Director of the Leibniz Institute for Solar Physics (KIS), is very happy about the outstanding results: "The project was rather risky because such telescope upgrades usually take years, but the great team work and meticulous planning have led to this success. Now we have a powerful instrument to solve puzzles on the Sun." The new optics of the telescope will allow scientists to study magnetic fields, convection, turbulence, solar eruptions, and sunspots in great detail. First light images obtained in July 2020 reveal astonishing details of sunspot evolution and intricate structures in solar plasma.

Telescope optics are very complex systems of mirrors, lenses, glass cubes, filters and further optical elements. If only one element is not perfect, for example due to fabrication issues, the performance of the whole system suffers. This is similar to wearing glasses with the wrong prescription, resulting in a blurry vision. Unlike for glasses, it is however very challenging to detect which elements in a telescope may be causing issues. The GREGOR team found several of those issues and calculated optics models to solve them. For example, astigmatism is one of such optical problems, which affects 30-60% people's vision, but also complex telescopes. At GREGOR this was corrected by replacing two elements with so-called off-axis parabolic mirrors, which had to be polished to 6 nm precision, about 1/10000 of the diameter of a hair. Combined with several further enhancements the redesign led to the sharp vision of the telescope. A technical description of the redesign was recently published by the Astronomy & Astrophysics journal in a recent article led by Dr. L. Kleint.

In early June 2011, NOAA Fisheries researchers and colleagues placed satellite tags on 26 loggerhead sea turtles in the Mid-Atlantic Bight. The tagging was part of ongoing studies of loggerhead movements and behavior. The Mid-Atlantic Bight, off the U.S. East Coast, is the coastal region from Cape Hatteras, North Carolina to southern Massachusetts. A little more than 2 months later, on August 28, Hurricane Irene passed through the area, putting 18 of the tagged turtles in its direct path. The researchers were able to track changes in the turtles' behavior coinciding with the hurricane, and found that they reacted in various ways.

"Hurricanes are some of the most intense weather events loggerheads in the mid-Atlantic experience, and we thought it was worth investigating how turtles in our dataset may be influenced by these dramatic environmental changes," said Leah Crowe, a contract field biologist at the NOAA Northeast Fisheries Science Center's laboratory in Woods Hole, Massachusetts, and lead author of the study published recently in Movement Ecology. "It was a perfect storm situation in terms of location, timing, and oceanographic conditions. We found that the turtles responded to the changes in their habitat in different ways."

Satellite tags attached to a turtle's carapace, or shell, transmitted the turtles' location and dive behavior. They also recorded sea-surface temperatures and temperature-depth profiles for approximately 13 months. This enabled the researchers to investigate the movements of 18 juvenile and adult-sized loggerhead turtles and associated oceanographic conditions as the hurricane moved through the region.

Most of the turtles moved northward during the hurricane, aligning themselves with the surface currents -- perhaps to conserve energy. Researchers observed longer dive durations after the hurricane for turtles that stayed in their pre-storm foraging areas. Some dives lasted an hour or more, compared with less than 30 minutes for a typical dive before the storm.

The turtles that left their foraging areas after the hurricane passed moved south earlier than would be expected, based on their normal seasonal movements. This change was also more than a month earlier than the typical seasonal cooling in the water column, which is also when the foraging season for loggerhead turtles ends in the Mid-Atlantic Bight.

"Loggerheads experience environmental changes in the entire water column from the surface to the bottom, including during extreme weather events," said Crowe. "This study was an opportunistic look at turtle behavior during a hurricane. Their behavior makes loggerheads good observers of oceanographic conditions where they forage."

The study was conducted by researchers at the Northeast Fisheries Science Center and colleagues at the nearby Coonamessett Farm Foundation in East Falmouth, Massachusetts. The team has tagged more than 200 loggerheads in the Mid-Atlantic Bight since 2009.

This work has created a continuous time-series of data on loggerhead sea turtles. With 10 years of data, researchers can now get a deeper understanding of how turtles behave and what environmental factors drive them. They can also look back at the data and ask new questions, as they did in this study.

Waters in the Mid-Atlantic Bight are highly stratified, or layered, by temperature in the summer. At the surface, water is warm. A cold layer, also called a cold pool, forms beneath this warm layer and is present from May to October. The presence of the cold pool overlaps with the Atlantic hurricane season, which runs from June through November. It also overlaps with the presence of foraging loggerheads that are in the area between May and September.

Hurricane modeling is especially difficult in the Mid-Atlantic Bight because of the cold pool. In this study, it was unclear which aspect of the environmental changes prompted behavioral changes. Previous studies have found that loggerhead behavior appears to be sensitive to changes in water temperatures throughout the water column. Hurricanes cause the water layers to mix, which creates cooler surface temperatures. The mixing also disrupts the thermocline -- the boundary layer between warm surface waters and colder, deeper waters.

Ocean temperature data recorded by the turtles' satellite tags are consistent with observations from weather buoys and autonomous gliders operating in the region. Depending on how many tags are deployed, data from tagged turtles can cover a more extensive area within a season than other oceanographic data sources.

More measurements of water temperatures throughout the water column in the region could help improve oceanographic models. Researchers say data from the turtle tags are an underused resource that has the potential to improve weather models, including hurricane models.

Many of the natural and human-induced impacts on sea turtle behavior, or the environments that sea turtles live in, are still unknown.

Previous studies indicate that sounds from dredge operations, seismic activity,offshore wind farm development, and marine recreation may also impact sea turtle distribution and dive behavior. Turtles might be impacted directly or through habitat alterations. While studies have looked at how tropical storms and hurricanes affect some marine species, there are few examples of examining sea turtle interactions with large storms.

In this study, turtle behavior did not return to pre-storm behavior within 2 weeks after the storm.

"The long-term cumulative effects of a changing climate and the increase in intensity of hurricanes and other storms is something that needs to be looked at. Changes in sea turtle movements and behavior can affect abundance estimates and management decisions," Crowe said. "This study reminds us that turtles live in a dynamic environment, and we cannot assume their behavior will be consistent throughout space and time."

In laboratory studies, Johns Hopkins Kimmel Cancer Center and Johns Hopkins University researchers observed a key step in how cancer cells may spread from a primary tumor to a distant site within the body, a process known as metastasis.

Trying to determine how groups of cells migrate to other parts of the body, the scientists used tissue engineering to construct a functional 3D blood vessel and grew breast cancer cells nearby. They observed the cancer cells reaching out to the blood vessel and taking over a patch of the cell wall. As a result of this attachment to the blood vessel, a cluster of tumor cells were easily released into the bloodstream to travel to distant sites. Cancer cells also were able to constrict blood vessels, cause them to leak, or pull on them.

A description of the work was published online July 14 in the journal Cancer Research.

"We observed that cancer cells can rapidly reshape, destroy or integrate into existing blood vessels," says senior study author Andrew Ewald, Ph.D., co-director of the Cancer Invasion and Metastasis Program at the Johns Hopkins Kimmel Cancer Center and professor of cell biology at the Johns Hopkins University School of Medicine. The work was conducted in close collaboration with the lab of Peter Searson, Ph.D., the Joseph R. and Lynn C. Reynolds Professor of Materials Science and Engineering, with joint appointments in the departments of biomedical engineering, oncology and physical medicine and rehabilitation.

"Just as people going scuba diving versus ice climbing require different tools, cancer cells bring different equipment depending on the job they intend to perform," Ewald says. "Determining what that equipment is can help us understand how to stop cancer." In this case, Ewald and collaborators expected to see groups of eight to 10 cells leaving a tumor, migrating through a protein barrier and squeezing between blood vessel walls to travel.

"We never saw that," he says. "What we kept seeing instead was that a piece of an existing tumor would take over a neighboring blood vessel wall, putting cancer cells in direct contact with the circulation, and that the cancer cells could do so in a matter of hours. They didn't have to invade past the blood vessels; they became the blood vessels, and could just release cancer cells there."

The "mosaic" vessels that result -- named because they consist of some natural blood vessel cells and some cancer cells -- were observed in about 6% of blood vessels in human breast tumors and in a mouse model of breast cancer in this and other studies, Ewald says. They also have been found in deadly brain tumors called glioblastomas, melanoma skin cancers and gastric cancers, he says. Their presence is associated with increased distant metastases.

The 3D model could be adapted to study additional aspects of the tumor microenvironment or to study alternate cancer types, Ewald says.

There's more to seawater than salt. Ocean chemistry is a complex mixture of particles, ions and nutrients. And for over a century, scientists believed that certain ion ratios held relatively constant over space and time.

But now, following a decade of research, a multinational study has refuted this assumption. Debora Iglesias-Rodriguez, professor and vice chair of UC Santa Barbara's Department of Ecology, Evolution, and Marine Biology, and her colleagues discovered that the seawater ratios of three key elements vary across the ocean, which means scientists will have to re-examine many of their hypotheses and models. The results appear in the Proceedings of the National Academy of Sciences.

Calcium, magnesium and strontium (Ca, Mg and Sr) are important elements in ocean chemistry, involved in a number of biologic and geologic processes. For instance, a host of different animals and microbes use calcium to build their skeletons and shells. These elements enter the ocean via rivers and tectonic features, such as hydrothermal vents. They're taken up by organisms like coral and plankton, as well as by ocean sediment.

The first approximation of modern seawater composition took place over 130 years ago. The scientists who conducted the study concluded that, despite minor variations from place to place, the ratios between the major ions in the waters of the open ocean are nearly constant.

Researchers have generally accepted this idea from then on, and it made a lot of sense. Based on the slow turnover of these elements in the ocean -- on the order of millions of years -- scientists long thought the ratios of these ions would remain relatively stable over extended periods of time.

"The main message of this paper is that we have to revisit these ratios," said Iglesias-Rodriguez. "We cannot just continue to make the assumptions we have made in the past essentially based on the residency time of these elements."

Back in 2010, Iglesias-Rodriguez was participating in a research expedition over the Porcupine Abyssal Plain, a region of North Atlantic seafloor west of Europe. She had invited a former student of hers, this paper's lead author Mario Lebrato, who was pursuing his doctorate at the time.

Their study analyzed the chemical composition of water at various depths. Lebrato found that the Ca, Mg and Sr ratios from their samples deviated significantly from what they had expected. The finding was intriguing, but the data was from only one location.

Over the next nine years, Lebrato put together a global survey of these element ratios. Scientists including Iglesias-Rodriguez collected over 1,100 water samples on 79 cruises ranging from the ocean's surface to 6,000 meters down. The data came from 14 ecosystems across 10 countries. And to maintain consistency, all the samples were processed by a single person in one lab.

The project's results overturned the field's 130-year old assumption about seawater chemistry, revealing that the ratio of these ions varies considerably across the ocean.

Scientists have long used these ratios to reconstruct past ocean conditions, like temperature. "The main implication is that the paleo-reconstructions we have been conducting have to be revisited," Iglesias-Rodriguez explained, "because environmental conditions have a substantial impact on these ratios, which have been overlooked."

Oceanographers can no longer assume that data they have on past ocean chemistry represent the whole ocean. It has become clear they can extrapolate only regional conditions from this information.

This revelation also has implications for modern marine science. Seawater ratios of Mg to Ca affect the composition of animal shells. For example, a higher magnesium content tends to make shells more vulnerable to dissolution, which is an ongoing issue as increasing carbon dioxide levels gradually make the ocean more acidic. "Biologically speaking, it is important to figure out these ratios with some degree of certainty," said Iglesias-Rodriguez.

Iglesias-Rodriguez's latest project focuses on the application of rock dissolution as a method to fight ocean acidification. She's looking at lowering the acidity of seawater using pulverized stones like olivine and carbonate rock. This intervention will likely change the balance of ions in the water, which is something worth considering. As climate change continues unabated, this intervention could help keep acidity in check in small areas, like coral reefs.

The act of giving and receiving increases well-being: the recipient benefits directly from the gift, and the giver benefits indirectly through emotional satisfaction. A new study published in the journal PNAS now suggests that those who share more also live longer. In their analysis, Fanny Kluge and Tobias Vogt found a strong linear relationship between a society's generosity and the average life expectancy of its members. The researchers at the Max Planck Institute for Demographic Research in Rostock, Germany, conclude that people are living longer in societies whose members support each other with resources.

"What is new about our study is that for the first time we have combined transfer payments from state and family and evaluated the effect", says Fanny Kluge. The researchers used data for 34 countries from the National Transfer Accounts project. For all countries, state and private transfer payments received and given by each individual over his or her lifetime are added up and presented in relation to lifetime income.

Societies in Western European countries share a lot and live long

Sub-Saharan African countries such as Senegal share the lowest percentage of their lifetime income and have the highest mortality rate of all the countries studied. Those who share little die earlier. Although South Africa is economically more developed than other African countries, few resources are redistributed; here too, the mortality rate is relatively high. In these countries, the mortality rate of children and young people up to the age of 20 is also higher than in the other countries studied. "Our analyses suggest that redistribution influences the mortality rate of a country, regardless of the per capita gross domestic product," says Fanny Kluge.

Societies in Western European countries and Japan transfer a lot to the youngest and oldest and mortality rates are low. The countries studied in South America also have high transfer payments. There, people share more than 60 percent of their average life income with others. The mortality rates are lower than in sub-Saharan Africa, but higher than those of Western Europe, Australia, Japan and Taiwan.

In France and Japan, the two countries with the lowest mortality rates of all the countries studied, an average citizen shares between 68 and 69 percent of their lifetime income. Here, the risk of dying in the coming year is only half as high for people over 65 as in China or Turkey, where between 44 and 48 percent of lifetime income is redistributed.

"What I find particularly interesting is that the relationship between generosity and lifetime income that we described does not depend on whether the benefits come from the state or from the wider family," says Fanny Kluge. Both of these factors cause the population live longer compared to societies with fewer transfer payments.

SCIENTISTS LOOK TO CELL RECYCLING TOOLS FOR NEW WAYS TO TREAT PARKINSON'S DISEASE

Media Contact: Vanessa Wasta, M.B.A., wasta@jhmi.edu

Researchers at Johns Hopkins Medicine are taking a closer look at the molecular machinery that recycles mitochondria, the cell's powerhouse, in efforts to ramp up the production of the energy-producing structures. Problems with mitochondria are a key aspect in the development of Parkinson's disease.

In a study posted online Aug. 13, 2020, in the journal Stem Cell Reports, the researchers focused on brain cells called neurons which release a chemical messenger called dopamine. These so-called dopamine neurons have long been associated with processing behaviors involving reward and motivation, but they've also been implicated in regulating movement.

Tremors, muscle stiffness and other movement problems are common among people with Parkinson's disease, which affects nearly 1 million people in the United States.

To study neurons associated with the disorder, scientific tools have recently been developed. These include fluorescent probes that can be easily used to identify newly developed and older mitochondria, says Ted Dawson, M.D., Ph.D., professor of neurology and director of the Institute for Cell Engineering at the Johns Hopkins University School of Medicine.

Dopamine neurons, as well as other cells, maintain a quality control process that degrades old, worn-out mitochondria and makes new ones. Scientists have long known that malfunctioning mitochondria are found in dopamine neurons. In addition, a gene called PARKIN has been associated with a type of hereditary Parkinson's disease that begins to appear in people younger than 40.

To better understand the gene's behavior, Dawson's team analyzed human dopamine neurons that lacked the PARKIN gene and were derived from both embryonic stem cells and people with Parkinson's disease. These neurons lost their ability to make new, fully functional mitochondria.

The scientists noticed that the PARKIN-lacking neurons with malfunctioning mitochondria had more activation of a protein-making gene called PARIS which is linked to mitochondria regulation.

When Dawson and his colleagues genetically engineered the neurons to remove the PARIS and PARKIN genes -- and thus their protein products -- the neurons were still able to manufacture new mitochondria and continue -- although to a lesser extent -- to remove old mitochondria.

Cells with more PARIS activation lose the ability to make new mitochondria and neurons with less PARIS seem to make mitochondria easily, with some -- but not total -- effect on old mitochondrial removal. Dawson says this seems to indicate that the production of new mitochondria is critical to the maintenance and survival of dopamine neurons.

"Targeting PARIS with drugs to lower its protein levels may provide a new way to treat Parkinson's disease," says Dawson.

The value of patents owned by Valted LLC could be affected by the study described in this news item. Dawson is a founder of Valted LLC and holds an ownership equity interest in the company. This arrangement has been reviewed and approved by The Johns Hopkins University in accordance with its conflict of interest policies.

STUDY LOOKS TO PAST TO DEFINE NEED FOR FUTURE DIVERSITY AMONG INTERNAL MEDICINE PHYSICIANS

Media Contact: Michael E. Newman, mnewma25@jhmi.edu

According to U.S. Census Bureau and academic projections, the United States population will look much different in 2060 than it does today. Of the nearly 420 million Americans expected in 40 years, it's likely that 60% will be racial and ethnic minorities while adults age 65 or older will make up 25%. Looking ahead, researchers at Johns Hopkins Medicine and the Association of American Medical Colleges (AAMC) recently asked if the workforce in internal medicine of that time will properly reflect the diverse country it will serve.

They looked at how diversified that workforce has become over the past four decades -- to gain insight into what will be needed in the future -- in a study posted online Sept. 1, 2020, in JAMA Network Open.

"The projected changes in the U.S. population of 2060 will lead to a larger, more diverse population, with increasingly complex medical care needs that will bear directly on the health and economy of future generations," says study lead author S. Michelle Ogunwole, M.D., a fellow in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine and a 2020 Health Disparities Research Institute Scholar selected by the National Institute on Minority Health and Health Disparities. "A larger, more diverse physician workforce could help meet these needs and improve patient outcomes."

For their study, the researchers used data from the Association of American Medical Colleges (AAMC) Faculty Roster and Applicant Matriculation File to capture full-time U.S. medical school faculty and matriculated students, and population data from the U.S. Census Bureau. The period examined was 1980 to 2018.

The researchers used this information to calculate the proportions of women and individuals from racial/ethnic groups who are underrepresented in medicine (URM) among internal medicine faculty and the faculty in all other clinical departments. These ratios were then compared with (1) the proportion of females and URM matriculants in U.S. medical schools and (2) the proportion of female and underrepresented minorities in the total population.

In 2018, the researchers report, women made up 40.3% of U.S. internal medicine faculty, but that is still lower than the women faculty in all other clinical departments (43.2%). During the study period, the percentage of URMs more than doubled but still makes up only a small percentage -- 9.7% in 2018 -- of all internal medicine physicians.

The researchers also state that the number of women among medical school matriculants grew steadily over the 38-year study span and now closely matches the U.S. female population percentage (50.7% to 50.8%). Although the percentage of URM matriculants has nearly doubled since 1980, the study shows it still lags far behind underrepresented minorities in the U.S. population (18.1% to 31.5%).

"Our findings show that progress has been made in diversifying academic internal medicine faculty; however, it still represents a low proportion of the discipline's workforce and does not yet reflect the nation's population," says study senior author Sherita Golden, M.D., M.H.S., vice president and chief diversity officer for Johns Hopkins Medicine and professor of medicine at the Johns Hopkins University School of Medicine. "Continued efforts to increase this diversity could greatly improve the quality of medical education and, in turn, better meet the health care needs of a society that is rapidly diversifying itself."

"This conversation is timely as we grapple with the racial disparities in COVID-19 outcomes and think about the complex chronic diseases that may have contributed to those disparities, as well as the ones that will persist long after this pandemic abates," Ogunwole says.

MOTOR LEARNING PROCESSES INFLUENCE HOW HUMANS LEARN NEW BEHAVIORS

Media Contact: Waun'Shae Blount, wblount1@jhmi.edu

Motor behaviors are part of all basic human activities, from talking and breathing to standing, walking and playing instruments or sports. These motor skills require that the nervous system first learns how to move by creating internal commands and then, with the commands in place, enable humans to repeat the movements thereafter. In a paper published in the July 25, 2020, issue of The Neuroscientist, a team of Johns Hopkins Medicine and University College London researchers explain the underlying bases behind such learning.

By reviewing previously completed behavioral and neurophysiological studies by Johns Hopkins Medicine and other sources that used two noninvasive brain stimulation techniques, the researchers evaluated data to better define the "big picture" about motor learning. This enabled a more comprehensive understanding of how humans learn new motor skills and which parts of their brain are involved. This information is critical to help design approaches to enhance learning or leverage it in the context of rehabilitation.

"In the long run, we hope to see if stimulating specific parts of the brain can increase motor function, especially in patients who are recovering from some form of brain injury," says physiatrist-in-chief Pablo Celnik, M.D., director of both the Department of Physical Medicine and Rehabilitation and the Center of Excellence in Stroke Treatment, Recovery and Rehabilitation at the Johns Hopkins University School of Medicine.

Researchers in previous studies have used two noninvasive and painless brain stimulation techniques to asses patient motor learning and performance progress. The methods, known as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), are designed to impact specific areas of the brain by delivering mild shocks through the patient's skull. The stimulation allows for brief disruption of the function in those regions, enabling researchers to note any irregular behavior in the patient.

In the past, TMS has shown benefits for patients with depression for whom antidepressant medications provide no help or cannot be tolerated. Similarly, research also has demonstrated cognitive improvement in some patients undergoing tDCS, showing that the technique may be helpful in treating depression, anxiety, Parkinson's disease and chronic pain. For patients with neurological diseases including spinal cord injuries, Alzheimer's disease and stroke, brain stimulation techniques may aid in a patient's recovery after a negative event. Through targeted rehabilitation techniques, such as TMS and tDCS, a patient's motor learning abilities can be improved as he or she adapts to new movements while regaining function.

Motor learning involves many different processes to ensure smooth and accurate movements. These processes enable those abilities that are learned by different areas of the brain -- such as playing competitive sports, performing a Beethoven symphony or rock climbing a mountain with bare hands.

"All of these functions interplay with each other in a very coordinated fashion," says Celnik.

Looking at the big picture revealed by analyzing data from numerous TMS and tDCS studies performed in Celnik's lab and others, the researchers identified the parts of the brain involved in the acquisition and retention of voluntary movements and motor skills. When tDCS was applied over specific brain regions that control some aspects of motor function, patients and healthy individuals showed increased excitement and better retention of their new motor memories.

Additionally, the authors reason that learning new skills involves different aspects of motor control with slightly different timings and roles during the overall learning process.

The researchers next plan to determine whether different learning processes can supplement each other during illness. If so, this would imply that when one area of the brain has a lesion, another part of the brain may be able to compensate. Such a finding would be significant because it could enable clinicians to develop better rehabilitation interventions that facilitate recovery after brain disease.

RACIAL/ETHNIC DISPARITIES IN CARE FOR PATIENTS WITH FAILING KIDNEYS UNCHANGED FOR DECADE

Media Contact: Michael E. Newman, mnewma25@jhmi.edu

It's well known that when a patient with chronic kidney disease (CKD) begins heading toward eventual organ failure, appropriate, thorough, personalized and timely care from a nephrologist in the year prior to the start of dialysis for end-stage kidney disease (ESKD) is the key to more successful patient outcomes and often, survival itself. However, a new study by Johns Hopkins Medicine, the Johns Hopkins Bloomberg School of Public Health, the Harvard Medical School and the Duke University School of Medicine shows that racial and ethnic disparities in the availability and quality of this critical care that existed in 2005 did not improve in the decade that followed.

The findings from this study were reported online Aug. 27, 2020, in JAMA Network Open.

Using data from the U.S. Renal Data System -- a national registry that collects, analyzes and distributes information about ESKD throughout the country -- the researchers studied more than 1 million who began maintenance dialysis treatment between Jan. 1, 2005, and Dec. 31, 2015. Mathematical models were used to examine national trends in the nephrology care these patients received at least 12 months prior to the start of their dialysis treatments, primarily to identify and document disparities in this care linked to race or ethnicity based on patient outcomes.

Successful outcomes, as documented in previous studies, may include improved patient survival odds; reduced hospitalizations and complications; increased quality of life; better preparation for dialysis; and greater chance of receiving a kidney transplant.

The measure of disparity in this study was the adjusted odds ratio. An adjusted odds ratio defines the likelihood that an outcome will occur in response to a specific factor, once all other potential confounding variables have been removed (adjusted).

The 1,000,390 adults evaluated were 54% White, 28% Black, 14% Hispanic and 4% Asian. More than half (54%) were women. Overall, 31% of patients received at least 12 months of predialysis nephrology care.

As a result of their retrospective evaluation, the researchers found that compared with White adults between 2005 and 2007, the odds of receiving predialysis nephrology care was 18% lower for Black adults; 33% lower for Hispanic adults; and 16% lower for Asian adults. Between 2014 and 2015, similar disparities were observed: 24% lower for Black adults; 39% lower for Hispanic adults; and 10% lower for Asian adults.

"Our findings suggest that national strategies are desperately needed to address the continuing -- and life-threatening -- racial and ethnic disparities in predialysis nephrology care," says study lead author Tanjala Purnell, Ph.D., M.P.H., an associate director of both the Johns Hopkins Urban Health Institute and the Johns Hopkins Center for Health Equity, as well as assistant professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health with a joint faculty appointment in the Department of Surgery at the Johns Hopkins University School of Medicine.

When the brain isn't getting enough oxygen, estrogen produced by neurons in both males and females hyperactivates another brain cell type called astrocytes to step up their usual support and protect brain function.

In the face of low brain oxygen that can occur with stroke or other brain injury, these astrocytes, star-shaped brain cells that help give the brain its shape and regularly provide fuel and other support to neurons, should become "highly reactive," increasing cell signaling, releasing neuroprotective factors and clearing neurotoxins, scientists report in The Journal of Neuroscience.

Astrocytes also should start producing protective estrogen, but it's neurons' producing estrogen that is critical to the protective cascade, they report.

"Astrocytes are always there and hovering and supporting," says Dr. Darrell W. Brann, neuroscientist and Virendra B. Mahesh Distinguished Chair in Neuroscience in the Department of Neuroscience and Regenerative Medicine at the Medical College of Georgia at Augusta University.

"When something bad happens, they are supposed to go into overdrive, get big and pushy, but this work suggests that you have to have neural estrogen for that to happen," Brann says.

The scientists say that theirs appears to be the first report demonstrating that neuron-derived estrogen is critical to astrocyte activation following an ischemic injury like a stroke. They reason that by understanding how estrogen is controlled, it will unlock therapeutic targets to one day help regulate the hormone's protection in the brain in the face of these maladies, as well as potentially normal aging.

Brann and Dr. Ratna Vadlamudi, molecular biologist and professor of obstetrics and gynecology at the University of Texas Health, San Antonio, are co-corresponding authors on the study and co-principal investigators on the National Institute of Neurological Disorders and Stroke grant that helped fund it.

"The hallmark of activation is astrocytes get very large, hypertrophic, their volume increases tremendously," says Brann, often more than doubling in size, he says, although he has no evidence they increase in number.

To try to understand how astrocytes take on this enhanced role, they knocked out the enzyme aromatase, which is critical to estrogen production, in neurons in the forebrain, the largest region of the human brain, in their animal model.

They found that one way estrogen made by neurons is protective in ischemia is by suppressing signaling of the fibroblast growth factor, FGF2, which is also made by neurons and known to suppress astrocyte activation, Brann and his colleagues write. Normally neurons use this FGF2 brake to help keep astrocyte response from getting out of control.

In this scenario, when they used a neutralizing antibody to block FGF2, astrocytes became more active and neuron damage was decreased. "The astrocyte activation came back and we saw the protective growth factors that they make," Brann says. Giving more estrogen produced similar benefits, including improving cognition after ischemia.

But without the ability to make aromatase, and consequently estrogen, in the male and female neurons, they found activation of astrocytes was significantly reduced, brain estrogen levels were decreased and the results included worse damage to neurons and cognitive dysfunction following a period of ischemia. When they looked closer, they found changes in pathways and genes associated with astrocyte activation, brain inflammation and oxidative stress in the aromatase knockouts.

They also saw less of known neuroprotective growth factors, like brain derived neurotrophic factor and insulin-like growth factor 1, which astrocytes normally release at an increased rate in response to a stressor like ischemia, and more suppressive substances like the brake FGF2.

The findings are more evidence that decreased activation of astrocytes has functional consequences to astrocytes' role in neuroprotection, Brann says.

"We know estrogen can just go right out of the astrocyte to the neuron and help regulate neuron protection," he says. It also can help regulate microglia, another type of glial cell in the brain -- astrocytes also are glial cells -- that instead releases inflammatory factors that can exacerbate damage.

Activated astrocytes also help clear glutamate, the brain's most abundant excitatory neurotransmitter that normally helps neurons communicate. But without estrogen from the neurons, the glutamate transporter, GLT-1, which removes about 90% of the glutamate, is significantly decreased and the chemical can accumulate at toxic levels in the brain and become a major cause of neuron destruction. "Glutamate is essential for brain function, but if it's overproduced, it's brain toxic," Brann says.

When all is going well in the brain, only neurons appear to be a local estrogen source, but with a stressor like ischemia, aromatase and the estrogen it enables are known to increase significantly in the astrocytes as well, if they are activated.

"We know that you have to have astrocyte activation to have the aromatase activated," Brann says. "We only see aromatase in astrocytes when they are activated after an injury, after a stress," Brann says. When aromatase goes up, is when they can start making estrogen, he says of the star-shaped supporter cells. That just did not happen in their knockouts.

Now they want to learn more about why astrocytes typically don't produce aromatase and resulting estrogen routinely, and exactly why they do in ischemia. They think those answers will provide even more direction for possible intervention, again for males and females, with oxygen challenges to the brain. Brann notes there are research compounds that produce estrogen in the brain they will be working with in the lab moving forward, which may be a good option since there are health concerns, including for the breast and uterus, about increasing estrogen bodywide, Brann says.

Brann's lab reported last year in The Journal of Neuroscience that estrogen in the brain is important to neurons communicating and making memories and that when male and female neurons don't make estrogen, they have less dense spines and synapses, key communication points for neurons. At the time, Brann said it was direct evidence that neuron-derived estrogen is a critical messenger for these.

While the neuroprotection afforded in these studies was essentially equal between males and females -- they removed the ovaries in the females to remove peripheral estrogen from the equation -- Brann's lab and others have evidence of gender differences in areas like the impact on memory. For example, they have found a more significant impact in females, about 90% versus 60%, in the molecular basis of memory, called long-term potentiation, when neurons could not produce estrogen, suggesting that brain-derived estrogen may have a bigger regulatory role in females, Brann says.

Brann also has some evidence that estrogen in the brain also has ongoing roles in both male and female brains. "When you have a challenge is when you see that role very clearly," he says.

There is no evidence that without estrogen, astrocytes turn on the neurons they typically support, rather they no longer can provide their usual protection, Brann notes. There also is no evidence that estrogen produced by the neurons themselves goes up in response to low oxygen.

Dr. Yujiao Lu, a recent PhD graduate in neuroscience from The Graduate School at AU who is now a postdoctoral fellow with Brann, is the study's first author. Collaborators also include Drs. Gangadhara R. Sareddy, Uday P. Pratap and Rajeshwar R Tekmal from the Department of Obstetrics and Gynecology at the University of Texas Health, San Antonio.

Ischemic strokes account for 87% of strokes, according to the American Heart Association. Like circulating estrogen levels in females, brain-derived estrogen also decreases with age in both sexes.

A team of international scientists have devised a new monitoring and reporting framework to help protect World Heritage Sites from almost 300 different invasive alien species globally including, rats (Rattus spp.), cats (Felis catus), lantana (Lantana camara) and Argentine ants (Linepithema humile).

Lead author Dr Ross Shackleton joined invasive species experts from around the globe - including CABI's Dr Arne Witt - who suggest the new 'tool' could ultimately help protect World Heritage Sites like the Galápagos, Serengeti and Aldabra Atoll from future threats.

UNESCO World Heritage Sites, are areas of outstanding universal value and conservation importance. However, they are threatened by a variety of global change drivers, including biological invasions from a range of terrestrial, freshwater and marine-based invasive alien species.

The team, who assessed biological invasions and their management in 241 natural and mixed World Heritage Sites from documents collated by UNESCO and the International Union for Conservation of Nature (IUCN), found that reports on the status of biological invasions were often inconsistent.

The research, published in Biodiversity and Conservation, outlined that while some reports were 'very informative', the scientists say they were hard to compare because no systematic method of reporting was followed.

Dr Shackleton added, "Detailed information on invasive alien species management undertaken in World Heritage Sites was available for fewer than half of the sites that listed invasive alien species as a threat.

"There is clearly a need for an improved monitoring and reporting system for biological invasions in World Heritage Sites and likely the same for other protected areas globally."

The new framework devised by the scientists, which has been tested at seven World Heritage Sites, covers collecting information and reporting on; pathways, alien species present, impacts, management, predicting future threat and management needs, the status of knowledge and gaps, and, assigning an overall 'threat score' to the protected area.

Dr Witt said, "We need urgent action right now to reduce the severity of these threats that include a range of invasive alien plant species - such as Mimosa pigra and Prosopis juliflora - and we believe that the development of this monitoring and reporting framework is a step in the right direction to protecting areas moving forward."

Based upon a previous review of invasive plants in the Serengeti-Mara ecosystem, Dr Witt added, "Failure to act could, for instance, see the devastation of the Serengeti-Mara ecosystem as we know it and that would have a major impact upon the annual wildebeest migration." Dr Jäger concurs, "Invasive mammals and invertebrates in Galápagos threaten some of the animals made famous by Darwin, such as the giant tortoise and Darwin's finches."

In testing the devised framework, which categorises the level of threat posed by invasive alien species as 'very high', 'high', 'moderate' and 'low; the researchers have already yielded more information than from past monitoring initiatives.

For example, the invasive alien species threat level indicated in the 2017 IUCN World Heritage Outlook for the Serengeti, Keoladeo, Doñana and the Vredefort Dome sites was 'data deficient' or 'low threat' or 'not listed', whereas all of these World Heritage Sites are now categorised as facing 'moderate' to 'high' threats from biological invasions.

Co-author Prof. David Richardson said, "World Heritage Sites face growing threats from a range of biological invasions which impact upon native biodiversity and the delivery of ecosystem services. Not only that but invasive alien species are a financial burden as costs for management can be extremely high."

"One key element of the new framework is listing all invasive alien species present where we can track the changes in threat or implementation of effective management over time."

This is exemplified by work done on Aldabra Atoll where, according to co-author Dr Nancy Bunbury, "There has been a decrease in the number of IAS listed due to effective eradications highlighting great management success at the site over the last few years."

The scientists, in their recommendations, also suggest that funding should be made available to conduct surveys at all under-resourced World Heritage Sites, to inform the reactive 'state of conservation' assessments undertaken by UNESCO and IUCN, and that monitoring could also be enhanced by members of the public as part of a series of 'citizen science' projects.

The emergence of artificial intelligence and machine learning techniques is changing the world dramatically with novel applications such as internet of things, autonomous vehicles, real-time imaging processing and big data analytics in healthcare. In 2020, the global data volume is estimated to reach 44 Zettabytes, and it will continue to grow beyond the current capacity of computing and storage devices. At the same time, the related electricity consumption will increase 15 times by 2030, swallowing 8% of the global energy demand. Therefore, reducing energy consumption and increasing speed of information storage technology is in urgent need.

Berkeley researchers led by HKU President Professor Xiang Zhang when he was in Berkeley, in collaboration with Professor Aaron Lindenberg's team at Stanford University, invented a new data storage method: They make odd numbered layers slide relative to even-number layers in tungsten ditelluride, which is only 3nm thick. The arrangement of these atomic layers represents 0 and 1 for data storage. These researchers creatively make use of quantum geometry: Berry curvature, to read information out. Therefore, this material platform works ideally for memory, with independent 'write' and 'read' operation. The energy consumption using this novel data storage method can be over 100 times less than the traditional method.

This work is a conceptual innovation for non-volatile storage types and can potentially bring technological revolution. For the first time, the researchers prove that two-dimensional semi-metals, going beyond traditional silicon material, can be used for information storage and reading. This work was published in the latest issue of the journal Nature Physics [ref 1]. Compared with the existing non-volatile (NVW) memory, this new material platform is expected to increase storage speed by two orders and decrease energy cost by three orders, and it can greatly facilitate the realization of emerging in-memory computing and neural network computing.

This research was inspired by the research of Professor Zhang 's team on "Structural phase transition of single-layer MoTe2 driven by electrostatic doping" [ref 2], published in Nature in 2017 ; and Lindenberg Lab's research on "Use of light to control the switch of material properties in topological materials", published in Nature in 2019 [ref 3].

Previously, researchers found that in the two-dimensional material-tungsten ditelluride, when the material is in a topological state, the special arrangement of atoms in these layers can produce so-called "Weyl nodes", which will exhibit unique electronic properties, such as zero resistance conduction. These points are considered to have wormhole-like characteristics, where electrons tunnel between opposite surfaces of the material. In previous experiment, the researchers found that the material structure can be adjusted by terahertz radiation pulse, thereby quickly switching between the topological and non-topological states of the material, effectively turning the zero-resistance state off and then on again. Zhang's team has proved that the atomic-level thickness of two-dimensional materials greatly reduces the screening effect of the electric field, and its structure is easily affected by the electron concentration or electric field. Therefore, topological materials at two-dimensional limit can allow the turning of optical manipulation into electrical control, paving towards electronic devices.

In this work, the researchers stacked three atomic layers of tungsten ditelluride metal layers, like nanoscale deck of cards. By injecting a small amount of carriers into the stack or applying a vertical electric field, they caused each odd-numbered layer to slide laterally relative to the even-numbered layers above and below it. Through the corresponding optical and electrical characterizations, they observed that this slip is permanent until another electrical excitation triggers layers to rearrange. Furthermore, in order to read the data and information stored between these moving atomic layers, the researchers used the extremely large "Berry curvature" in the semi-metallic material. This quantum characteristic is like a magnetic field, which can steer electrons' propagation and result in nonlinear Hall effect. Through such effect, the arrangement of the atomic layer can be read without disturbing the stacking.

Using this quantum characteristic, different stacks and metal polarization states can be distinguished well. This discovery solves the long-term reading difficulty in ferroelectric metals due to their weak polarization. This makes ferroelectric metals not only interesting in basic physical exploration, but also proves that such materials may have applicational prospects comparable to conventional semiconductors and ferroelectric insulators. Changing the stacking orders only involves the breaking of the Van der Waals bond. Therefore, the energy consumption is theoretically two orders of magnitude lower than the energy consumed by breaking covalent bond in traditional phase change materials and provides a new platform for the development of more energy-efficient storage devices and helps us move towards a sustainable and smart future.