Saturday, April 11, 2026

New study reveals great apes mirror facial expressions with surprising precision

Research suggests that orangutans and chimpanzees replicate happy facial expressions in ways similar to humans

University of Portsmouth

New research from the University of Portsmouth has found that great apes exhibit exactness in mimicking one another’s facial expressions in social contexts.

The study, published by Nature’s Scientific Reports, explored how orangutans and chimpanzees mirror expressions during social interactions, particularly laugh faces, drawing comparisons with human behaviours such as the Duchenne smile - a genuine smile that engages both the mouth and eyes.

The research, supported by a Royal Society Research Grant and funded by the Department of Science, Innovation and Technology, Leakey Foundation and the FEELIX GROWING project, reviewed behaviours of 96 great apes and investigated whether the animals mirrored each other's laugh faces within three seconds, examining both with and without their upper teeth exposed.

It analysed the behaviours of 39 orangutans and 57 chimpanzees living in eight separate groups, comprising a mix of ages and genders.

The study showed that the animals were most likely to mirror each other's expressions when the upper teeth were not exposed, as this is a gentler expression. These accurate ways of matching can help people better understand others’ emotions and predict how they might behave.

Measuring this mimicry provides scientists with unique insights into face-to-face exchanges, allowing them to test how exact the responses of primates really are. While humans are known for having precise and versatile language, this study suggests that great apes 10-16 million years ago already matched the level of facial communication exactness seen in humans - an ability that gave them important advantages.

The research also explored play duration and play intensity, analysing whether the length of a play session was linked to how likely the animals were to mirror their playmate's expression.

When orangutans engaged in longer play sessions, they showed a greater precision in mirroring their playmate's expression.

Lead author Diane Austry, who completed her Masters at the University of Portsmouth, said: “What we found was remarkable - these animals don't just replicate a general expression, they copy the exact same facial movement pattern their social partner uses, much like when a human mirrors another person's natural Duchenne smile.

“The apes showed the same pattern for both automatic rapid responses as well as more delayed responses.”

Dr Marina Davila Ross, co-author and Associate Professor in Comparative Psychology at the University of Portsmouth, said: “This level of explicit replication wasn't previously known across the great apes. What's more, these expressions are shared with humans – previous research measuring muscle activity shows that chimpanzees and humans use the same muscles to produce laugh faces. This points to a real complexity in positive communication across great apes.”

While both orangutans and chimpanzees showed such level of exactness in their facial responses, they seemed to differ in how this was done. The chimpanzees appeared to avoid mimicking the upper tooth rows of their social partners in order not to signal risky play, which might be disadvantageous to match, at least when interacting with older partners or males.

Dr Davila-Ross from the University of Portsmouth’s School of Psychology, Sport and Health Sciences and Centre for Comparative and Evolutionary Psychology added: “In the future, we are interested in exploring how these expressions might be used beyond play.

“The concept of evolutionary continuity is fascinating - in humans, smiles serve many purposes, from expressing happiness to conveying mockery, so it would be interesting to examine these expressions outside of a play context.”

The orangutans involved in this study lived at the Sepilok Orangutan Rehabilitation Centre (SORC) near to Kabili-Sepilok Forest Reserve in Malaysia. The chimpanzees lived in large outdoor enclosures in the Chimfunshi Wildlife Orphanage (CWO) in Zambia.

Journal

Nature

DOI

10.1038/s41598-026-43992-w

Method of Research

Observational study

Subject of Research

Animals

Article Title

Towards the complexity of laugh communication in great apes: exact facial replications in laugh faces of orangutans and chimpanzees

Article Publication Date

9-Apr-2026

Rock bonding changes understanding of earthquakes mechanics

Forschungszentrum Juelich

Portrait photo Dr. Bo Persson — image:
Pioneer in Friction Science
Bo Persson has played a leading role in shaping tribology – the science of friction, wear, and contact – for decades. His theory of contact mechanics describes how rough surfaces come into contact, providing a foundation for a wide range of applications in friction research. Among other topics, he has studied friction in systems as diverse as car tires, touchscreens, and glaciers.

The Swedish-born physicist is currently an emeritus researcher at Forschungszentrum Jülich and collaborates with research institutions in China. In recognition of his scientific achievements, he was awarded the Tribology Gold Medal, the highest honor in the field.
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Credit: Forschungszentrum Jülich / Sascha Kreklau

Deep within the Earth’s crust, massive tectonic plates shift. But what happens at the microscopic level? Physicists from Forschungszentrum Jülich and Saarland University have proposed a new explanation: The rock grains do not simply interlock – they bond together at their contact points.

When tectonic plates move, they rarely do so smoothly. Sometimes they slide almost imperceptibly; at other times, stress is suddenly released – resulting in an earthquake. What exactly governs this behavior remains one of the key open questions in earthquake research.

From a physical perspective, the problem comes down to friction. To better understand the underlying processes, the researchers studied friction between granite surfaces – an established model system for tectonic faults. Combining experiments, simulations, and theory, they arrive at a clear conclusion: friction in rocks arises differently than previously thought.

Bonding instead of scratching

Conventional models attribute friction mainly to mechanical effects: rough surfaces interlock, wear down, and sharp asperities scratch grooves into the material. Most earthquake models are based on these assumptions.

However, the new findings challenge this view. “Wear is not the dominant factor. Instead, we were able to show that another mechanism governs friction,” explains Dr. Bo Persson from the Peter Grünberg Institute (PGI-1) in Jülich.

At microscopic contact points, rock surfaces form chemical bonds – a process similar to cold welding. “As rocks slide past each other, these bonds continuously form and break. This requires energy – and that is what generates friction,” says Bo Persson.

The researchers also showed an important size-effect. “For small systems the bond breaking occurs uniformly while for large systems the bond-breaking occurs non-uniformly – some regions start to slip before other regions – which reduces the so called breakloose friction force,” Persson adds.

Insights from simulations

The results are supported by computer simulations carried out at Saarland University. Prof. Martin Müser and his team have been studying friction between solids under extreme conditions for many years.

“In our simulations, we identified the breaking of bonds as the main source of friction,” explains Martin Müser. “In addition, deformation and local melting processes in the material affect the friction – effects that also play a role in existing models.”

A new perspective on earthquakes

The findings suggest that tectonic plates behave differently at the microscopic level than previously assumed. Traditional models assume that stress builds up over time and is then suddenly released in a rupture.

The new model paints a different picture: motion begins much earlier. The plates are never completely at rest but move continuously – albeit extremely slowly, often at rates of just fractions of a nanometer per second. This corresponds to only a few millimeters per year and is known as “creep.”

From creep to slip

At the microscopic level, chemical bonds are constantly breaking and reforming. As velocity increases, friction initially rises because more bonds must be broken per unit time. However, once a critical threshold is reached, the system changes: bonds can no longer reform quickly enough, and local heating effects occur. As a result, friction suddenly drops.

“The system transitions from slow creep to rapid sliding – and that could be a key trigger of earthquakes,” says Persson.

The findings could help refine existing models. “We need a better understanding of how friction depends on motion,” Persson adds. “That could be crucial for describing earthquake processes more realistically.”

Pioneer in Friction Science

Bo Persson has played a leading role in shaping tribology – the science of friction, wear, and contact – for decades. His theory of contact mechanics describes how rough surfaces come into contact, providing a foundation for a wide range of applications in friction research. Among other topics, he has studied friction in systems as diverse as car tires, touchscreens, and glaciers.

The Swedish-born physicist is currently an emeritus researcher at Forschungszentrum Jülich and collaborates with research institutions in China. In recognition of his scientific achievements, he was awarded the Tribology Gold Medal, the highest honor in the field.

Journal

Reports on Progress in Physics

DOI

10.1088/1361-6633/ae4b66

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Granite sliding on granite: friction, wear rates, surface topography, and the scale-dependence of rate–state effects

A new route to faster PPP-AR

Aerospace Information Research Institute, Chinese Academy of Sciences

image:
Schematic diagram of multi-layer MF.
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Credit: Satellite Navigation

Fast, precise Global Navigation Satellite System (GNSS) positioning depends on how well models describe the ionosphere, the electrically charged region that bends and delays satellite signals. A new study shows that a more realistic, multi-layer view of that region can improve one of the field’s most demanding techniques: Precise Point Positioning with integer Ambiguity Resolution (PPP-AR). Instead of treating the ionosphere as a single thin shell, the new method divides it into multiple layers and uses that structure to convert Vertical Total Electron Content (VTEC) into Slant Total Electron Content (STEC) more effectively. The payoff is modest in appearance but meaningful in practice: faster convergence, better early-stage positioning, and especially strong gains in equatorial regions where ionospheric gradients are hardest to tame.

That matters because conventional Precise Point Positioning (PPP) still struggles with time. Even when accurate enough, it often takes too long to converge, partly because ionospheric effects are difficult to model cleanly. The standard Single Layer Model (SLM) mapping function remains widely used, but it is less effective where Total Electron Content (TEC) changes rapidly across space, especially at low latitudes. As global ionospheric maps improve, the mapping function itself becomes a more important source of error. Due to these challenges, there is a need to carry out in-depth research on better ionospheric mapping methods that can support faster, more reliable Precise Point Positioning with integer Ambiguity Resolution (PPP-AR) performance.

Researchers from the University of Warmia and Mazury in Olsztyn (UWM), the German Aerospace Center (DLR), DLR Gesellschaft für Raumfahrtanwendungen mbH (GfR), and the European Space Agency (ESA) reported (DOI: 10.1186/s43020-026-00193-0) in 2026 in Satellite Navigation that they had validated a new multi-layer ionospheric mapping function for PPP-AR. The study tested whether replacing the conventional single-shell assumption with a layered ionosphere model could improve how GNSS users convert Vertical Total Electron Content (VTEC) information into slant corrections that are directly useful for positioning.

The team evaluated the method in two ways. First, they tested it in the positioning domain using an uncombined PPP-AR model. Second, they checked it in the Global Navigation Satellite System (GNSS) observation domain by comparing converted Slant Total Electron Content (STEC) values with benchmark estimates from the Geometry-Free (GF) linear combination. The dataset included nine permanent GNSS stations spanning high, middle, and low latitudes, with winter and summer test periods in 2019. Across most stations and periods, the multi-layer mapping functions outperformed the conventional SLM. On average, the PPP-AR filter converged 4–10% faster when the multi-layer approach was used. In the summer 2019 tests, mean convergence time across all stations fell from 11.4 minutes with SLM to 10.3 minutes with the Multi-Layer (ML) blind model; in winter 2019, it fell from 14.3 to 13.8 minutes. The benefit was strongest near the equator. At the BOAV station, for example, mean convergence time dropped from 21.7 minutes to 19.2 minutes when the ML blind mapping function replaced the conventional model. The new method also improved early-stage positioning: averaged across all stations, the mean three-dimensional Root Mean Square (RMS) error in the second epoch decreased from 0.529 m to 0.518 m in summer 2019, while in winter 2019 it decreased from 0.569 m to 0.558 m.

“This is the kind of improvement that matters precisely because it appears at the start,” the study suggests. “In high-precision GNSS, the first minutes often determine whether a method feels practical or frustrating. By making ionospheric corrections more faithful to reality, the multi-layer approach helps PPP-AR settle faster and behave better where the ionosphere is most difficult—especially in equatorial skies.”

The implications are broader than one correction model. Faster convergence can make PPP-AR more attractive for real-world navigation, surveying, and other applications that cannot afford long initialization delays. The study also shows where future gains are likely to matter most: low-latitude regions, where conventional assumptions break down fastest. Even the computational cost remained manageable, with the ML blind approach requiring only about 10% more processing time than SLM. In other words, this is not just a theoretical refinement. It is a practical case for how better ionospheric structure can translate into better positioning performance.

###

References

DOI

10.1186/s43020-026-00193-0

Original Source URL

https://doi.org/10.1186/s43020-026-00193-0

Funding Information

The work is funded by the LMAP (LEO Ionospheric Mapping Assessment and Derivation For Precise PVT Applications) project under the ESA Contract No. 4000142821/23/NL/MGu/my and in part by the National Science Centre, Poland, Project No. 2023/48/Q/ST10/00059.

About Satellite Navigation

Satellite Navigation (E-ISSN: 2662-1363; ISSN: 2662-9291) is the official journal of Aerospace Information Research Institute, Chinese Academy of Sciences. The journal aims to report innovative ideas, new results or progress on the theoretical techniques and applications of satellite navigation. The journal welcomes original articles, reviews and commentaries.

Journal

Satellite Navigation

DOI

10.1186/s43020-026-00193-0

Subject of Research

Not applicable

Article Title

Validation of a multi-layer approach-based ionospheric mapping function supporting PPP-AR

Article Publication Date

1-Apr-2026

Sport clubs became lifelines during public health crisis, research shows

University of Stirling

Sport clubs became lifelines for vulnerable communities during the Covid pandemic, new research by the University of Stirling has shown.

The study found many groups transformed their role from sport providers into critical sources of social support during the public health crisis.

Led by Dr Claudio Rocha, Senior Lecturer in Sport, and co-authored by Dr Jennie Morgan, Senior Lecturer in Heritage, the study explores how small, community sports clubs (CSOs) in Brazilian favelas responded to the Covid pandemic, and whether their actions helped communities cope and recover.

Based on interviews with 13 sport managers across four favela regions, the research found that rather than shutting down when sport activities were halted by public health restrictions, organisations adapted rapidly.

With limited access to technology and infrastructure, online delivery was not viable. Instead, CSOs pivoted to meet urgent needs – distributing food parcels, sharing public health information, transporting residents to vaccination centres, and forming partnerships with NGOs and local groups.

Dr Rocha said: “Sports clubs in some of the world's most deprived urban communities can act as a critical social safety net during crises – stepping in where governments do not.

“Our research showed that organisations in Rio de Janeiro favelas stepped up during the Covid crisis, delivering food, supporting public health efforts, and filling critical gaps left by government services.

“In doing so, they didn’t just survive, they became more trusted and embedded in their communities, creating a virtuous cycle where communities supported them in return.

“We also found that poorer communities are far more exposed to the damage extreme emergencies cause, yet the very organisations doing the most to protect them are often excluded from the academic and policy conversation around crisis management.

“Our research has real implications for how policymakers should think about supporting such communities before the next emergency hits – whether a pandemic, flood, or economic shock.

“Policymakers should recognise and fund community sports organisations in deprived areas not only as sport providers, but also as essential emergency infrastructure, meaning that when the next crisis hits, the most vulnerable communities have a stronger, better-resourced network of local organisations ready to hold them together.”

The research extends stakeholder theory of crisis management by recognising CSO managers themselves as affected stakeholders. Many faced personal hardship during the crisis yet continued to lead community responses.

The study suggests resilience develops in stages – starting with individuals, then organisations, and ultimately the wider community.

The findings highlight three key drivers of community resilience: strong leadership and responsibility among managers, the ability to fill gaps left by limited public sector support, and a commitment to equality, diversity, and inclusion.

The research also underlines the broader significance of CSOs as part of the social safety net in deprived communities. In the absence of sufficient government support, these organisations became central to crisis response, demonstrating their capacity to mobilise resources and protect vulnerable populations.

The efforts made by CSOs strengthened trust and cooperation, with many residents later giving back to the organisations that had supported them.

Researchers argue that policymakers should better recognise and support CSOs – not only as sport providers but as essential emergency infrastructure. Strengthening partnerships between governments and community organisations could significantly improve preparedness and response in future crises.

While the findings are grounded in the specific context of Brazilian favelas, they offer valuable lessons for similarly disadvantaged communities worldwide.

The study Managing community sport organisations in favelas during crisis: impacts on community resilience was published in the journal Social Sciences.

It was funded by Stirling Crucible, a development opportunity created by the University of Stirling for its researchers.

Journal

Social Sciences

Subject of Research

People

Article Title

Managing community sport organisations in favelas during crisis: impacts on community resilience

Street green space can help cool cities, but it will not be enough on its own

International Institute for Applied Systems Analysis

Cities are on the front line of climate change, with rising temperatures and heat stress posing growing risks to health, productivity, and livability. Street green space, such as trees and vegetation along streets, is often promoted as a practical nature-based solution because it can provide shade, cooling, and other positive benefits, for example, improving the mental health of citizens. Yet, evidence on how much cooling street greenery can deliver, to which extent the amount of vegetation can be increased, and how much cooling can be expected in future climates, has remained limited, particularly when taking a global view across very different urban forms and climate zones.

In the new study, a team of researchers from IIASA and VITO Belgium combined high-resolution street greenery data with 100-meter urban microclimate model outputs for 133 cities worldwide, providing a neighborhood-scale assessment with global coverage. Rather than relying on satellite-based surface temperature alone, the team assessed how street green space relates to air temperature and wet-bulb globe temperature – a measure that captures heat stress more appropriately than temperature alone, because it accounts for humidity, wind, and radiation.

The results show that street greenery can help reduce heat stress in cities, but its benefits are uneven and depend strongly on local conditions. Generally, the cooling effect is stronger in tropical and continental climates, while it is generally weaker in dry and temperate climates. The cooling potential is also shaped by urban form: the most consistent benefits tend to appear in open and low-rise neighborhoods, as well as in large low-rise areas, where greenery has more room to interact with the local microclimate.

“In practical terms, this means that greener streets can make a measurable difference, but not everywhere to the same degree,” explains Steffen Lohrey, co-lead author of the study, former guest researcher at IIASA, and Promovendus at the Institute for Environmental Studies, VU University Amsterdam.

Also, upper feasible levels of street greenery expansion differ across climates, with drier or continental regions generally facing tighter limits than tropical or temperate ones. This means that the places with the greatest need for cooling are not always the places where large expansions of greenery are easiest to achieve.

The authors then explored what these findings could mean by 2050 under different climate and urban greening scenarios. They found that, under a “current policies” climate scenario, expanding street greenery at levels that are ambitious but still realistic for each city, could offset about 3% to 11% of the expected increase in maximum wet-bulb globe temperature. Under a high-emissions scenario, this cooling effect is smaller, reducing the increase by about 2% to 7%, depending on local conditions. The authors also warn that if street greenery declines, either due to lack of action or because plants are stressed by extreme weather conditions, urban heat could become even more severe.

“For policymakers and city planners, our findings suggest that investing in street greenery is worthwhile, but that it is not a substitute for broader action, which is chiefly increasing efforts to reduce greenhouse gas emissions. On the adaptation side, greening needs to be integrated with other measures, such as improved building materials, and better urban design”, notes Niels Souverijns, Senior Climate Scientist at VITO and a co-author of the article.

The study also highlights the importance of maintaining existing vegetation and paying attention to where greening occurs within cities, so that adaptation does not deepen existing inequalities in heat exposure.

“By providing globally comparable evidence across 133 cities, the study helps clarify both the promise and the limits of street green space as an urban climate adaptation strategy. It shows that greener streets can play an important role in reducing heat stress, but that safeguarding urban populations in a warming world will require more comprehensive and context-specific responses,” concludes Giacomo Falchetta, co-lead author of the study and a Research Scholar in the IIASA Energy, Climate and Environment Program.

Reference
Falchetta, G., Lohrey, S., Souverijns, N., Lauwaet, D., Schleussner, C.-F., and Niamir, L. (2026). Street green space is relevant but not sufficient for adapting to growing urban heat in world cities. Environmental Research Letters DOI: 10.1088/1748-9326/ae5c20

About IIASA:
The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe. www.iiasa.ac.at

Journal

Environmental Research Letters

DOI

10.1088/1748-9326/ae5c20

Article Title

Street green space is relevant but not sufficient for adapting to growing urban heat in world cities

Article Publication Date

7-Apr-2026

Scientists discover the antibacterial potential of ‘hero’ Korean skincare ingredient

University of Kent

Fans of Korean skincare may be familiar with ‘hero ingredient’ Madecassic acid for its skin-soothing properties, but researchers at the University of Kent have revealed its greater potential for use in the battle against antibiotic resistance.

Using a combination of computational screening and laboratory experiments, scientists in the School of Natural Sciences together with those at University College London (UCL) have demonstrated how this natural chemical from the common Asian herb Centella asiatica, is an effective antibacterial drug.

Their findings come at a time when drug-resistant bacteria pose a serious worldwide health challenge, with predictions that bacterial antimicrobial resistance will cause 39 million deaths between 2025 and 2050. The race to create new antibiotics is costly and slow, so any advance in this area can prove an important breakthrough. As Kent researchers have demonstrated here, applying modern methods to analyse natural plant extracts is bringing those breakthroughs a step closer.

The study, published in RSC Medicinal Chemistry, showed that madecassic acid, a plant chemical and known anticancer agent, can inhibit the ability of antibiotic-resistant E. coli to grow. This molecule binds strongly to the cytochrome bd complex, a respiratory protein complex that does not exist in humans and animals but is essential for the survival of many pathogenic bacteria during infection. When it binds to the cytochrome bd, the madecassic acid stops it from functioning normally, suggesting that this natural product could serve as an alternative antimicrobial.

One of the advantages of madecassic acid as an antibacterial drug is that it has a chemical structure that is amenable to modification. The scientists isolated madecassic acid from a plant extract in Vietnam and modified it to create three different variants. All variants effectively inhibited cytochrome bd and shut down bacterial growth, with one variant also killing E. coli at higher concentrations. Future work will build on these findings to optimise madecassic acid as a more effective drug.

These findings also provide insights into how this plant extract component might impact upon bacterial skin flora when used in skincare products.

Lead author Dr Mark Shepherd, Reader in Microbial Biochemistry at Kent said: ‘Plants have been a source of natural medicines for millennia, and now contemporary research approaches can reveal the mechanisms of action. This is an exciting time, and we hope to further our understanding of natural antimicrobials from plants, nature’s great chemical factories.’

The article (University of Kent: Samantha A. Henry, Geraud N. Sansom, Ryan A. Boughton, Guy Joiner, Calum M. Webster, Michelle D. Garrett, Gary K. Robinson and Mark Shepherd) is available at https://doi.org/10.1039/d5md01116g

Journal

RSC Medicinal Chemistry

DOI

10.1039/d5md01116g

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Investigating the role of cytochrome bd oxidases in the antibacterial activity of madecassic acid and derivatives thereof