Tech

The CAS key lab of quantum information makes a significant progress in quantum orienteering. Under the lead of Prof. GUO Guangcan, LI Chuanfeng, XIANG Guoyong and collaborators enhanced the performance of quantum orienteering with entangling measurements via photonic quantum walks. These results were published online by Physical Review Letters on February 13th.

Thanks to quantum entanglement, quantum information processing is much more efficient than its classical counterpart in many tasks, like quantum computation, quantum communication, quantum metrology, and so on. Quantum entanglement can manifest itself in both quantum states and quantum measurements. On contrast to the extensive research of entangling states, there are few experimental studies of entangling measurements because entangling measurements are difficult to realize. In recent years, Prof. Guo-Yong Xiang et. al. developed a method of realizing quantum entangling measurements via photonic quantum walks, and their method not only has high fidelity but also is deterministic. They have used this technology to achieve unprecedented efficiency in quantum state tomography [Nature Communications 9,1414(2018)], and reduce the back action of quantum measurements in quantum thermodynamics [Science Advances 5,3(2019)]. Recently, they used their technology to enhance quantum orienteering.

In quantum orienteering, Alice wants to use quantum resources to communicate a random space direction to Bob, which is of military importance. A simple scheme is that Alice can polarize a spin along the direction and sends it to Bob. As early as 1999, Nicolas Gisin from University of Geneva found that the antiparallel spins were more efficient than parallel spins in quantum orienteering. That is different from the classical counterpart, in which the efficiencies of the two direction encoding schemes are the same. There is no entanglement in quantum states on Alice's side, thus it is the entanglement in quantum measurements on Bob's that boosts the efficiency. As optimal entangling measurements on parallel and antiparallel spins are difficult to realize, there has been no convincing experimental implementation for more than 20 years. Prof. Guo-Yong Xiang et. al. successfully realized such optimal entangling measurements via quantum walks. The experimental results clearly demonstrate that entangling measurements can extract more direction information than local measurements, and the fidelity of antiparallel spins has an improvement of 3.9% than parallel spins in orienteering.

Their work demonstrated a truly nonclassical phenomenon that is owing to entanglement in quantum measurements instead of quantum states. Meanwhile, it offers an effective recipe to realizing entangling measurements in photonic systems. These results are of interest not only to foundational studies of quantum entanglement and quantum measurements, but also to many applications in quantum information processing.

Lithium batteries are easy to explode? Scientists at University of Science and Technology of China (USTC) may have a way to prevent.

In modern life, lithium-ion batteries are used as mobile power sources in all aspects of daily life, thus the safety of lithium-ion batteries is very important. As a key component of lithium-ion batteries, the separators strongly influence the performance and in particular the safety of lithium batteries.

However, under the stress of external shock, the widely used microporous polyolefin separator is easily deformable, accompanied with the change of inside porous network, including the pore closure, leading to the inhomogeneous Li+ ion flux in the lithium battery, which will create high local current density to trigger lithium dendrite growth on the electrode, resulting in short-circuit and even explosion of lithium batteries.

Therefore, it is very important to develop a good impact resistant separator for improving the safety of lithium batteries.

Recently, a research team led by professor YAO Hongbin, NI Yong and YU Shuhong from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences proposed a nacre-inspired coating on the separator to improve the safety of lithium battery under external impact. The study was published in Advanced Materials.

In the study, they developed an alkaline-solution-induced etching method in the aragonite platelets to dissolve the protein matrix along with some parts of amorphous calcium carbonate to yield porous structure.

Then they developed a nacre-inspired separator via fabricating multilayered coating consisted of the porous aragonite platelets (PAPs) bonded by the polymer to replace the commercial ceramic nanoparticle coating. The PAP-coated separator (PAPCS) exhibits a higher tensile strength, better electrolyte wettability, and smaller thermal shrinkage in comparison to the commercial ceramic nanoparticle coated separator (CNCS).

Besides showing a little better thermal stability and electrochemical performance, the PAPCS can endow the battery with more excellent deformation-resistant capability than the CACS when encountering the external impaction. They used the same pellets to impact CNCS and nacre-inspired coating separator at the same height, and then used scanning electron microscopy to observe changes in the pore structure of the separator. They found that the pore structure inside the nacre-inspired coating separator was well retained by the impact of the small pellet, while the internal pores of the CNCS showed a very pronounced deformation due to the impact. Also, they showed that the pouch cell using the fabricated nacre-inspired separator exhibits good cycling stability under external shock, which is in sharp contrast to the fast short circuit of the pouch cell using commercial CNCS.

The developed nacre-inspired protection strategy will open a new avenue for improving the safety of lithium batteries. The researchers believe the methodology used in this study is very suitable for industrialization. However, more stringent testing of the current separator is required before it is actually industrialized. If it can pass the characterization test of the battery industry, this project can be industrialized in the next two years.

Next, the researchers are looking for novel bio-inspirations to develop new separators with high mechanical properties and lithium-ion transference number. They want to build a prismatic/nacre composite membrane material that further enhances the impact resistance of lithium-ion batteries. Their ultimate goal is to provide advanced separators for high performance and safe lithium batteries.

Bottom Line: The U.S. Preventive Services Task Force (USPSTF) concludes that current evidence is insufficient to make a recommendation about screening for cognitive impairment in adults 65 or older. The USPSTF routinely makes recommendations about the effectiveness of preventive care services and this statement updates and reaffirms its 2014 statement that also concluded "the evidence was insufficient to assess the balance of benefits and harms of screening for cognitive impairment." Dementia is a significant decline in one or more areas of cognition that interferes with a person's independence in daily life and the condition affects an estimated 2.4 to 5.5 million people in the U.S.

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

(doi:10.1001/jama.2020.0435)

FOLSOM, Calif., February 25, 2020 –- According to a new epidemiological study, women in their late 50s and early 60s who consumed at least two servings of walnuts per week had a greater likelihood of healthy aging compared to those who did not eat walnuts. After accounting for various factors that could impact health in older adults, such as education and physical activity, walnuts were the only nut associated with significantly better odds of healthy aging.

In this study, which was supported by the California Walnut Commission, "healthy aging" was defined as longevity with sound mental health and no major chronic diseases, cognitive issues or physical impairments following the age of 65.

By 2034, for the first time ever, older adults will outnumber children. Baby boomers (those 65 and older) are expected to make up 21% of the population, with more than half being women. The significance of this demographic turning point in our country's history is clear - research that examines the aging process, including simple, low-cost interventions like healthy food choices, will be especially crucial to healthier lifespans.

Previous research from primary investigator Dr. Francine Grodstein, formerly of Brigham and Women's Hospital, has found that eating walnuts may have a positive impact on reducing the risk for physical impairments in older adults as well as cognitive decline. Additionally, others in the same research group have found decreases in cardiovascular disease and type 2 diabetes - all conditions that become more common as we age. There is no one solution to slowing down the effects of aging, but adopting the right habits, like snacking on a handful of walnuts, can help.

In this study, Grodstein looked at data from 33,931 women in the Nurses' Health Study (NHS) to evaluate the association between nut consumption and overall health and well-being in aging. Between 1998-2002, female nurses in the NHS were asked about their diet (including total nut consumption); evaluated for chronic diseases (such as cancer, heart attack, heart failure, stroke, type 2 diabetes and Parkinson's disease); and assessed for memory concerns, mental health and physical limitations (including daily activities like walking one block, climbing a flight of stairs, bathing, dressing oneself and pushing a vacuum cleaner). Of the study participants, 16% were found to be "healthy agers," defined as having no major chronic diseases, reported memory impairment or physical disabilities as well as having intact mental health.

Although previous research has connected a healthy diet, including walnuts, to better physical function among older men and women, this study only included women. More research is needed to understand if these results hold true among men. Additionally, participants were not assigned to eat walnuts or other foods; they were simply asked about their dietary choices. It is possible that subjects misreported their dietary intake since this information was collected by questionnaires. As an observational study, this does not prove cause and effect. However, this research sheds light on simple habits that can influence health during later years in life - such as eating walnuts.

While electric vehicles alone may not reduce carbon emissions, a new study reveals that when electric vehicles are powered with renewable energy and coupled with carbon policy strategies, they can help combat climate change without sacrificing economic growth.

In the study led by Assistant Professor Runsen Zhang at Hiroshima University, researchers combined economic and transport models and data from 17 regions around the world to produce six scenarios for transportation into the year 2100.

As many governments plan to phase out vehicles that rely on fossil fuels by 2050, Zhang's data provides additional information that could be applied to climate mitigation strategies and policies worldwide.

In one scenario where countries produced only electric vehicles (including cars, two-wheelers, buses, and small trucks) and also implemented a carbon pricing strategy, the global mean temperature increase peaked at 1.82 degrees Celsius in the year 2090 and settled at 1.8 degrees Celsius in 2100.

This figure is lower than the 2 degrees Celsius climate goal that all countries in the United Nations Framework Convention on Climate Change have proposed to constrain global warming to, relative to pre-industrial levels, as part of the Cancun Agreement. The results in this scenario with carbon pricing strategies could help meet the climate change mitigation goals.

"An electric vehicle policy is good for macroeconomic systems, but the condition is that we need a supporting policy and that is carbon pricing or renewable energy," said Zhang.

While a carbon pricing policy initially revealed a negative impact on the economic system (i.e. gross domestic product loss), when carbon pricing was coupled with policies that mandated electric road transportation, this electric vehicle policy ultimately alleviated negative impacts of carbon pricing on the economic system.

The study also revealed how carbon pricing strategies were more significant in reducing emissions than a high preference for renewable energy sources. However, a high preference for renewable energy sources, such as wind and solar power, still facilitated growth in the power sector, so renewable energy remains an important strategy to reduce carbon emissions and maintain economic stability or growth.

Zhang notes a large proportion of a vehicle's carbon footprint is generated at the factory before cars reach the road. The limitations of this study included that the dynamics of electrical vehicle charging were not considered, but it could be an area of future research.

A research group from Zhejiang University in China has found that the noncentrosymmetric compound CaPtAs is a superconductor, which shows evidence for unconventional properties. This compound provides a new opportunity for studying unconventional superconductivity in systems with broken inversion symmetry.

The lack of an inversion center in the crystal structure of a compound can have profound effects on its physical properties. The interesting phenomena which have been found to arise includes spin-splitting of the Fermi surfaces, the lifting of the four-fold degeneracy of a Dirac point to yield two doubly degenerate Weyl nodes in Weyl semimetals, magnetic skyrmions with complex spin textures, and the characteristic properties of noncentrosymmetric superconductors.

The intensive study of noncentrosymmetric superconductors can be traced back to 2004, when the first example of this class of materials with strong electronic correlations was discovered by E. Bauer et al. In such a superconductor lacking an inversion center, the symmetry-allowed antisymmetric spin-orbit coupling (ASOC) allows for the admixture of spin-singlet and spin-triplet pairing states, which can give rise to a nodal superconducting gap. This has been evidenced in the weakly correlated noncentrosymmetric superconductors Li2(Pt, Pd)3B, where H. Q. Yuan et al. found that the strength of the ASOC can tune the relative strengths of the singlet and triplet components in the superconducting pairing wave function. In recent years, an increasing number of noncentrosymmetric superconductors with novel properties have been discovered, where some systems have been theoretically predicted to potentially exhibit topological superconductivity.

Recently, noncentrosymmetric superconductors where there are weak correlations but time reversal symmetry is broken below the superconducting transition temperature, have been much discussed. However, most of the other properties of these systems appear to be analogous to those of conventional BCS superconductors, with a fully open superconducting gap. The origin of this unusual behavior still requires explanation.

Here a research group led by Prof. Huiqiu Yuan from the Center for Correlated Matter (CCM) and Department of Physics at Zhejiang University have discovered a new noncentrosymmetric superconductor CaPtAs with possible unconventional pairing, which is published in SCIENCE CHINA: Physics, Mechanics & Astronomy, entitled "CaPtAs: a new noncentrosymmetric superconductor".

CaPtAs is a member of the alkaline-earth based equiatomic ternary compounds, crystallizing in a noncentrosymmetric tetragonal structure (space group I41md, No.109) with three-dimensional (3D) honeycomb networks. This is different to compounds such as SrPtAs, BaPtAs, and BaPtSb, which have structures consisting of stacked hexagonal honeycomb layers. Both single- and poly- crystals of CaPtAs have been successfully synthesized, and bulk superconductivity is confirmed below 1.5 K. Measurements of thermodynamic properties indicate possible nodes in the superconducting gap, where the electronic specific heat is well fitted by a p-wave model, as shown in Figure 1(d). Further collaborative studies are currently ongoing to determine the nature of the superconducting pairing state of CaPtAs.

University of Otago researchers have contributed to an international study which helps improve the understanding of bacteria and viruses.

Published recently in the international science journal, Nature, the study reveals how bacterial immune systems can be harmful for their hosts, and why they are not found in all bacteria.

Researchers at the University of Exeter in the UK, with support from the University of Montpellier in France and the Otago team, made the suprising finding that existing CRISPR anti-viral immunity was often a disadvantage to the bacterium when infected by certain viruses.

CRISPR has become well known for its repurposing as a tool for precise genetic engineering. However, CRISPR systems (segments of DNA) naturally occur in many bacteria and have the important function of providing bacteria with immunity against viruses or foreign DNA.

This triggered a major question as to whether autominnunity is important in other bacterial pathogens. Otago researchers Dr Chris Brown, Dr Teyuan Chyou and Professor Peter Fineran, used bioinformatics to address this question by analysing more than 170,000 bacterial genomes, including diverse pathogens. The software used was developed by the Brown and Fineran groups at the University of Otago, while recent Otago PhD graduate Bridget Watson contributed to the experiments in the UK.

"We searched the DNA sequence for CRISPR systems and integrated viral genomes. We found that CRISPR autoimmunity was likely to be widespread in nature," Dr Brown says.

Professor Fineran explains this suggested that triggering the powerful CRISPR defence systems is risky for a bacterium. "Importantly, this may help answer a long-standing question of why these defence systems are absent in 60 per cent of bacteria."

For example, Staphylococcus aureus pathogens that often take up extra genes to become multidrug resistant, seldom have CRISPR defence. An example of this is MRSA (Methicillin-resistant Staphylococcus aureus) an infection often occurring in people who have been in hospitals or other healthcare settings like residential care homes, which has become resistant to many of the antibiotics used to treat ordinary staph infections. It seldom has CRISPR defence.

This study forms part of larger studies aimed at understanding the arms race between bacteria and their viruses and has significant implications.

"Importantly, this change in understanding of pathogen defence systems will inform the design of new treatments, particularly those using viruses that kill pathogenic or antibiotic resistant bacteria," Dr Brown explains.

An international team of scientists has found out that being treated disrespectfully can lead people to develop cynical beliefs about human nature. Cynical beliefs about human nature, in turn, contribute to again being treated disrespectfully by others - and behaving disrespectfully towards others oneself. Through elaborate cross-sectional, longitudinal and experimental studies, the scientists showed that disrespect and cynicism constitute a vicious circle.

The joint publication by the social psychologist Dr Daniel Ehlebracht (University of Cologne) as well as Dr Olga Stavrova (Tilburg University, Netherlands) and Dr Kathleen D. Vohs (University of Minnesota, USA), is now available in an online version and will soon appear in the Journal of Experimental Psychology: General.

The researchers used different methods: They proved the causal effect of experienced disrespect on cynicism as well as the opposite case, i.e., of cynicism on experiencing disrespect, in a total of five experimental studies with 1,149 participants, and one diary study with 462 participants.

A cross-sectional analysis of data from the European Social Survey (ESS) with representative population samples of European countries (a total of 53,333 respondents) showed a clear connection between experienced disrespect and cynicism in 28 out of 29 countries.

A longitudinal analysis of data from the US Health and Retirement Study (HRS) with a total of 19,922 respondents showed that, on the one hand, experienced disrespect predicted the development of cynicism over a period of four years. On the other hand, harboring cynical beliefs about human nature also made future experiences of disrespect more likely.

Daniel Ehlebracht remarked: 'When people are treated disrespectfully by others, they often tend to generalize their negative experiences and unwarrantedly consider other people to be immoral, unfair and selfish in general. However, such a distorted image of humanity can paradoxically lead to provoking renewed bad experiences with other people and also to a tendency to treat others badly oneself.'

According to Ehlebracht, the scientists' new findings can also help to understand why cynicism and disrespect towards others are on the rise in many societies.

Topological superconductor, with bulk superconducting gap and Majorana fermion states on the surface or edge, is one of the most sought after quantum materials. Topological superconductivity is of fundamental importance with potentially powerful application in topological quantum computation. The discovery of Weyl semimetals, in which the conduction and valence bands contact only at Weyl points in the Brillouin zone protected against gap formation by crystalline symmetry or time reversal symmetry, has stimulated great enthusiasm for exploring topological superconductivity in these materials. Especially, the superconductivity from the topological non-trivial surface state of Weyl semimetals could be very attractive but has not been reported yet.

The noncentrosymmetric orthorhombic TaIrTe4, has been considered as a time-reversal invariant Weyl semimetal with the minimal 4 Weyl points. Recently, Prof. Jian Wang and Xiong-Jun Liu at Peking University in collaboration with Minghu Pan at Huazhong University of Science and Technology and others reported the experimental evidences for the unconventional superconductivity generated by the surface states in TaIrTe4 from both scanning tunneling microscopy/ spectroscopy (STM/STS) and electrical transport measurements. They demonstrated the superconductivity of TaIrTe4 by both the superconducting gap from STS and the consistent resistance drop from electrical transport. The thickness-independent of ultralow critical current and angular dependence of upper critical field (Bc2) indicate that the superconductivity occurs only in the surface states. Furthermore, the temperature dependence of Bc2 behavior, the in-plane angle-dependent critical field and the stability of the superconductivity against the magnetization together support the p-wave-like topological nature of the quasi-1D superconductivity.

This discovery of quasi-1D surface superconductivity in Weyl semimetals offers a novel platform for exploring topological superconductors and may contribute to the rapidly developing field of topological quantum computation.

More than a decade ago, academics warned that mangrove forests were being lost faster than almost any other ecosystem, including coral reefs and tropical rainforests. But things are looking better.

An international team of 22 researchers from 24 institutes led by Associate Professor Daniel Friess and Dr Erik Yando of the Department of Geography at the National University of Singapore (NUS) have found that there is now cause for optimism, with the global loss rate of mangrove forests now less alarming than previously suggested. (Please refer to the Annex for the full list of contributing institutions).

After studying various earlier presented works, the team found that globally, mangrove loss rates have reduced by almost an order of magnitude between the late 20th and early 21st century - from what was previously estimated at one to three per cent per year, to about 0.3 to 0.6 per cent per year, thanks in large part to successful mangrove conservation efforts. This heightens conservation optimism amongst broader projections of environmental decline.

"The team deduced that the reduction in mangrove global loss rates has resulted from improved monitoring and data access, changing industrial practices, expanded management and protection, increased focus on rehabilitation, and stronger recognition of the ecosystem services provided by mangroves," explained Assoc Prof Friess.

A commentary summarising the team's findings was published in the scientific journal Current Biology on 24 February 2020. This international effort was the result of the Fifth International Mangrove Macrobenthos and Management conference (MMM5), the world's largest mangrove conference which was held for the first time in Singapore last year.

Positive change in mangrove conservation

Mangrove forests occur along the shorelines of more than 100 countries and are incredibly important as they provide a number of critical benefits to people, including protection from coastal erosion and storm as well as cyclone damage, natural filters for pollution and sediment, carbon sequestration which helps to mitigate climate change, and provide millions of people with products such as fuelwood, construction materials and fisheries resources, since mangroves act as nursing grounds for many coastal fishes.

"There is strong evidence that positive conservation change is occurring. Mangrove conservation has gained substantial momentum, with greater public and government awareness leading to investment and on-the-ground action. However, despite recent mangrove conservation successes, tempered optimism is necessary, as conservation gains are not evenly spread, nor guaranteed into the future," cautioned Assoc Prof Friess.

Mangroves under threat in emerging deforestation frontiers

The team gathered that mangroves continue to be threatened by aquaculture, agriculture and urban development across the world, particularly for new deforestation frontiers that are emerging throughout parts of Southeast Asia and West Africa. Southeast Asia is a traditional hot spot of mangrove deforestation as mangroves are cut down to make space for aquaculture ponds, cleared for rice paddy cultivation, and reclaimed for industrial and port development.

"Emerging deforestation frontiers need to be addressed early. Improved environmental governance and increased public intervention can help secure positive conservation outcomes in these locations. We need to take decisive steps to improve the success and scale of mangrove rehabilitation, and increase the resilience of mangroves to sea-level rise to maintain the current progress in mangrove conservation," commented Dr Candy Feller, Senior Scientist at the Smithsonian Environmental Research Center, who is one of the contributors to the study.

Maintaining current progress in mangrove conservation

The team also noted that while mangrove rehabilitation is lauded as a method to offset historical as well as ongoing losses and can yield long-term ecosystem service provision, successful rehabilitation is still a challenge to achieve at scale.

Current mangrove rehabilitation projects around the world can fail because key ecological thresholds and rehabilitation best practices are ignored - for instance, planting in low-intertidal locations that are not suitable for mangrove growth and using non-native species that can quickly become invasive, which gives rise to myriad ecological impacts on the intertidal zone.

Another contributor, marine ecologist Professor Karen Diele of Edinburgh Napier University added, "The challenge of mangrove rehabilitation is to ensure that the best practices are executed correctly, including monitoring of rehabilitation projects, both in terms of flora and fauna, to learn from failure and successes. Work is required to overcome key socio-political hurdles. These include lack of training, unclear land tenure, and national governments or NGO targets that incentivise rehabilitation efforts in unsuitable coastal locations. These are not insurmountable challenges and can be addressed through engagement with policy makers and stakeholders."

"Ensuring that mangrove conservation gains are not short-lived will require continued research, policy attention, and renewed efforts to improve the success of mangrove rehabilitation at a scale that will be ecologically impactful," said Dr Yando, Research Fellow at the NUS Department of Geography.

Meanwhile, Assoc Prof Friess and his team will continue to monitor mangrove deforestation and conduct studies to assess the benefits and values of mangroves in Southeast Asia.

Annex: Contributing Institutions

Department of Geography, National University of Singapore

Mangrove Specialist Group, International Union for the Conservation of Nature

Leibniz Centre for Tropical Marine Research

Institute for Coastal & Marine Research, Department of Botany, Nelson Mandela University

The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong

Department of Biology, University of Florence

Working Land and Seascapes, Smithsonian Institution

Smithsonian Marine Station

Ecology and Environment Research Centre, Department of Natural Sciences, Manchester Metropolitan University

Department of Geography, University of California

Australian Rivers Institute, School of Environment and Science, Griffith University

Department of Earth and Environmental Sciences, Macquarie University

Laboratory of Systems Ecology and Resource Management, Université Libre de Bruxelles

Ecology & Biodiversity, Laboratory of Plant Biology and Nature Management, Vrije Universiteit Brussel

School of Applied Sciences, Edinburgh Napier University

St Abbs Marine Station

Smithsonian Environmental Research Centre

Faculty of Geosciences, University of Bremen

Simon F S Li Marine Science Laboratory, The Chinese University of Hong Kong

Institute of Water and Environment, Florida International University

School of Earth, Atmospheric and Life Sciences, University of Wollongong

Institute of Ocean and Earth Sciences, University of Malaya

Division of Science, Yale-NUS College

Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University

With habitat loss threatening the extinction of an ever-growing number of species around the world, many wildlife advocates and conservation professionals rely on the proverbial 'canary in the coal mine'--monitoring and protecting a single representative species--to maintain healthy wildlife biodiversity.

But new research from UBC's Okanagan campus suggests that habitats are better served if conservation efforts focus on a collection of species rather than a single 'canary.'

"Efforts around the world are going into countering a decline in biodiversity," says Adam Ford, study author and Canada Research Chair in Wildlife Restoration Ecology at UBC Okanagan. "While we would love to be able to protect all habitats for all species, organizations tend to focus their efforts on a few species and not everyone shares the same priorities."

That, he says, is where the idea of surrogate species--or the canary in the coal mine--comes into play. But it's not without its drawbacks.

"The problem with surrogate species is that people rarely agree on which species that should be," says Ford. "And there is a tendency to favour charismatic species like grizzly bears and wolves, over lesser-known but equally-important species. These preferences are deeply rooted in cultural norms."

To address that imbalance in selecting surrogate species, Ford and his team began looking at how to group species together to present a more objective and representative sample of the habitats that need protecting.

By combing through a public dataset of over 1,000 species and 64 habitats in British Columbia, they were able to compare the surrogacy value of each species--a numerical score based on the association of two species through their use of shared habitats.

They found that a mixture of five to 10 game and non-game species offered the best value as surrogates for biodiversity conservation.

"We discovered what we called an 'all-star' team of species for each of the province's nine wildlife management units, as well as an all-star team for the province as a whole," says Sarah Falconer, graduate student at Laurentian University and study co-author. "Our findings suggest that if we commit to preserving these collections of species rather than just the charismatic megafauna, we're likely to achieve much better conservation outcomes."

Ford is quick to point out that the mixture of game and non-game species in their all-star teams mean that seemingly disparate groups, ranging from hunters to bird-watchers to hikers, have a vested interest in working together to protect each of their species for the benefit of all.

"Perhaps we should not be focusing on figuring out which species is the best conservation surrogate, but which groups of species bring the most people together to protect the most biodiversity," he says.

The fascinating and highly efficient jumping mechanism in flea beetles is described in a new research article in the open-access journal Zookeys. Despite having been known since 1929, the explosive jump - which is also the reason behind the colloquial name of this group of leaf beetles - has so far not been fully understood.

By joining forces, a team of Chinese and US scientists, led by Dr Xingke Yang, Siqin Ge and Yongying Ruan of the Chinese Academy of Sciences and Dr Alexander Konstantinov of the Agricultural Research Service at the U.S. Department of Agriculture, tested the existing theories, using micro-computed tomography (micro-CT scans), 3D reconstructions, high-speed filming and dissection. Following their experiments, the scientists provided comprehensive insights into the mechanics behind the spectacular jump in flea beetles and reported, for the first time, the role of a structure found in the legs of these insects, known as "elastic plate".

The flea beetles (members of the tribe Alticini) are plant feeders that belong to a hyperdiverse group of about 9,900 species and occur in various environments worldwide: from lowland tropical rain forests to high-altitude mountain meadows and deserts. Most of them live, feed and procreate on the upper leaf surface of their host plants, thus making them particularly vulnerable to predators, including birds, ants and spiders. One of their defence mechanisms is their incredible jumping skills, which allow the beetles to escape an approaching predator in an instant.

The apparatus responsible for this exceptional jump is hidden inside the beetle's hind legs and is relatively simple. It contains only three sclerotised parts and a few muscles. Yet, it is, in reality, a highly efficient "catapult", able to propel the beetle at a distance hundreds of times its body length. Using micro-computed tomography, 3D reconstructions and high-speed filming data, the scientists revealed that the acceleration during the jump can reach an explosive peak of 8,650 m/s2, which is 865 times the acceleration of gravity. The peak power output of the hind legs of the beetle peaked at 2.24 × 105 W/kg (per unit mass). This is about 450 times the capabilities of the fastest known muscle and 100~200 times that of a powerful rally car engine.

The 3D reconstructions revealed two processes inside the hind leg that amplify the power output of the beetle's muscles and reduce energy waste.

Firstly, the tibial extensor and tibial flexor muscles contract simultaneously and cumulatively build up elastic strain energy inside the femur (the longest segment of an insect's leg). The energy is stored in a sclerotised structure, called a metafemoral spring, while another two structures inside the leg, previously known as "triangular plate" and "elastic plate", act together as a trigger for the catapult mechanism. When the trigger is released, the metafemoral spring contracts and converts elastic potential energy into kinetic energy, which allows the flea beetle to attain an extraordinarily high acceleration. Instead of gradual acceleration throughout the jump, the flea beetle employs a 'high-efficiency mechanism' at the start, in order to store colossal strain energy to be released later on.

Thus, flea beetles avoid muscle fatigue (energy waste) and improve their jumping performance to the point where they can do over 30 consecutive jumps, as recorded by the scientists in their laboratory experiments. In nature, this mechanism is an adaptation for the insects to escape predators by quickly disappearing from the leaf surfaces where they normally spend their lives. In fact, it is this "explosive" jump that, according to the researchers, is amongst the key traits responsible for the high evolutionary success and remarkable species diversity in flea beetles.

In conclusion, the scientists note that the catapulting jump mechanism in flea beetles is so efficient and yet so simple that it might find an excellent use in robotics, as well as in engineering and industrial installations. In their research paper, they also propose a design of a bionic limb inspired by the studied beetles.

Reduced stress is linked to changes in the profile of plasma metabolites, a new study from the University of Eastern Finland shows. According to the researchers, the findings can shed light on the associations of psychological well-being with metabolism and the risk of disease. The study was published in Scientific Reports.

Psychological stress is known to be associated with obesity, low-grade inflammation and metabolic disorders, but the underlying mechanisms remain poorly understood. In the newly published study, the researchers used metabolite profiling to study whether improved psychological well-being is associated with measurable changes in metabolism. The study is a sub-study of Elixir, a large multi-centre lifestyle intervention study conducted by the Universities of Helsinki, Eastern Finland and Jyväskylä, and the Finnish Institute of Occupational Health.

The study participants were obese individuals with perceived psychological stress symptoms at the onset of the study. They were divided into two groups: one group to undergo a psychological lifestyle intervention (60 individuals) and a control group (64 individuals). Both groups managed to lose weight, but reduced stress and improved psychological well-being were reported by the intervention group in particular. Using metabolomics techniques, the researchers performed an extensive analysis of fasting metabolites in all study participants at beginning of the study and again nine months later, after the intervention had ended. Stress and psychological well-being were assessed by surveys and heart rate variability measurements.

Changes in the plasma levels of many phosphatidylcholines were associated with improved psychological well-being, and to some degree also with weight loss. Reduced stress and weight loss were associated with lower levels of certain lysophosphatidylcholines, and with higher levels of some plasmalogens. Obesity and the inflammatory marker interleukin-1 receptor antagonist, on the other hand, were inversely associated with these levels. The researchers also discovered previously unknown lipids that correlated with stress levels.

The observed associations of psychological well-being and weight loss with changes in the plasma lipid profile suggest that the lipids in question play a role in molecular-level mechanisms that interlink psychological and metabolic health.

The main reason for the existence of social banks is to fund other social enterprises. On that basis, Simon Cornée from the University of Rennes 1, Panu Kalmi from the University of Vaasa and Ariane Szafarz from the Université Libre de Bruxelles propose that social banks can operate profitably and still lend to their borrowers at attractive interest rates when their owners and depositors accept lower returns on their investments.

The three researchers use a large dataset on European banks to investigate this issue and find support for their hypotheses in their article The Business Models of Social Banks that was recently published in Kyklos. Their results help to understand the non-standard objectives of banking organisations.

How can social banks survive?

Social banks are still a relatively small part of the banking sector, but their asset growth during the period studied (1998-2013) was roughly twofold compared to the banking sector on average. Social banks are characterised by their adherence to social goals, transparency of operations, and need to be economically sustainable. They operate in a rather opaque and risky market when they lend to social enterprises. They create strong lending relationships and support to their clientele when they lend below the market prices. How do they manage to be economically self-sufficient?

The authors suggest that this is because their owners and depositors, who support the causes of the social enterprises to which social banks are lending, accept below-market returns on their investments. This leads into three core hypotheses: 1) social banks produce smaller returns to their owners than conventional banks; 2) they remunerate their depositors at below market interest rates; and 3) they grant loans below market interest rates. In their empirical analysis, they find support for all of these hypotheses.

Social banks have received only scant attention in the empirical banking literature, presumably because of their relatively small number. Cornée, Kalmi and Szafarz use a large dataset on European banks from 16 years (1998-2013). After doing extensive searches based on membership lists of social banking institutions, webpages, bank annual reports, and previous literature, they found 29 banks in 11 West European countries of which the primary business is to lend to social enterprises. Allowing for missing data for some banks for some years, they observed around 300 bank-year observations for social banks, which is less than 1% of the total number of observations.

Does ownership explain the results?

An important issue is whether the results related to social banks are due to their status as social banks, or due to the fact that many social banks are also stakeholder banks (cooperative or savings banks).

The authors suggest that even though social banks have many similarities with stakeholder banks and are characterised by lower returns to investors, the interest rate behaviour of social banks may well be rather different. For instance, the depositors of stakeholder banks are usually expecting higher, not lower interest rates.

The authors test this with a subsample consisting only of stakeholder banks and find out that both the interest rates social banks charge on their loans and pay on their depositors are significantly lower than those of stakeholder banks.

Zero interest rates create big challenges for social banks

For banks that operate with lower interest rates on both sides of the market, the movement towards zero nominal interest rates poses special challenges. If the zero interest rate is binding, one would expect that the pricing policies of social banks converge towards those of conventional banks when interest rates are approaching zero. By exploiting the variation of interest rates over time, the authors found support for the argument that the social spread on interest rates is not sustainable when interest rates approach zero. The dataset they use has however only a limited number of observations from the zero interest rate period, so the authors were not able to observe how social banks have adjusted to the prolonged period of zero interest regime.

The results are robust to alternative model specifications

As the main method, the authors employ matching methods. They match social banks with their four nearest neighbours with respect to country, ownership and size. This considerably reduces variation in the sample.

However, are the results specific to this particular way of constructing the sample? The authors further probe their results by using alternative methods on defining key variables, using a full sample instead of a matching sample and examining the selection based on unobservables. All their results remain valid in these robustness checks.

Cameras shooting up to 25,000 frames a second have been used to capture the moment two droplets of liquid come together and mix - and it is opening up research into new applications for 3D printing.

With one of the colour cameras positioned below the droplets and the other to the side, the synchronised system was able to record the moment one of the droplets passed over the other, creating a surface jet that formed less than 15 milliseconds - that is 15 thousandths of a second - after they coalesced.

Thomas Sykes, a PhD researcher at the University of Leeds and lead author of the study, said the use of high-speed imaging has provided a fresh insight into the complex way droplets behave when they interact, a branch of science known as fluid dynamics.

Mr Sykes, who is part of both the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in Fluid Dynamics at Leeds and the Leeds Institute for Fluid Dynamics, said: "The chemistry behind emerging 3D-printing technologies involves having chemicals deposited onto a surface. We often need those chemicals to be positioned in a highly specific way, for example we may want the droplets to lie side by side or for one droplet to rest on another.

"On other occasions we want them to mix completely, to produce a desired reaction to 3-D print more complex structures."

To get the desired droplet behaviour, scientists have tried to alter the surface tension of the droplets, making it easier for them to mix or to remain separate. But how to make that happen in the printing process is poorly understood.

In the study, the use of two synchronised cameras allowed scientists to see what was happening both on the surface and inside the droplets and to make a better assessment of mixing.

Dr Alfonso Castrejón-Pita, an Associate Professor and co-author of the study based at the University of Oxford, added: "In the past, there have been instances when two droplets impact and you were left wondering whether they have mixed or has one droplet just passed over the other. Having two cameras record the droplet interaction from different viewpoints answers that question."

The study is a collaboration between researchers at the University of Leeds, University of Oxford and Queen Mary University of London and the findings have been published in the journal Physical Review Fluids (The paper is available here: https://link.aps.org/doi/10.1103/PhysRevFluids.5.023602).

Future trends in 3-D printing

3D printing, also known as additive manufacturing, is an emerging technology that has its roots in computer printing. Instead of ink being put down on a page, 3D printers deposit chemicals in layers to build an object, often from a computer-aided design system.

Scientists hope to extend the range and type of products that can be manufactured by 3D printing, for example, high-precision "scaffolds" for tissue engineering in the laboratory, on which human tissue can be grown. But significant advances in the technology requires a clearer understanding of the way chemicals react when they are deposited by a 3D printer.

Dr Mark Wilson, an Associate Professor at Leeds and lead supervisor of the project, said: "The imaging techniques developed have opened-up a new window on droplet technology."

"We were able to expose the internal flows, whilst imaging at a sufficient speed to capture the fast dynamics. This experimental setup allows us to visualise how, by altering the surface tension of the droplets, we can alter their behaviour."