Bat wings boost hovering efficiency

EPFL researchers have designed flexible, batlike wings that boost lift and improve flight performance. This innovation could lead to more efficient drones or energy-harvesting technologies

Ecole Polytechnique Fédérale de Lausanne

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EPFL's deformable membrane wing.

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Credit: EPFL UNFOLD

 

In 1934, French entomologist Antoine Magnan wrote that bumblebees “should not be able to fly”, as their small wings should theoretically not be able to produce enough lift. It took modern high-speed camera technology to uncover what allowed airborne insects to fly: the leading-edge vortex. This phenomenon occurs when air flow around the leading edge of flapping wings rolls up into a vortex, creating a low-pressure region that boosts lift.

On the other hand, bats – with their flexible membrane wings – are able to fly just as well as insects, if not more efficiently. In fact, some bats have been found to expend as much as 40% less energy than moths of a similar size. Researchers in the Unsteady Flow Diagnostics Laboratory in EPFL’s School of Engineering set out to study the aerodynamic potential of more flexible wings using an experimental platform with a highly deformable membrane made from a silicone-based polymer. They found that instead of creating a vortex, the air flows smoothly over the curved wings, generating more lift and making them even more efficient than rigid wings of the same size.

“The main finding of this work is that the gain in lift we see comes not from a leading-edge vortex, but from the flow following the smooth curvature of the membrane wing,” says former EPFL student Alexander Gehrke, now a researcher at Brown University. “Not only does the wing have to be curved, but it has to be curved by just the right amount, as a wing that is too flexible performs worse again.”

Gehrke is the first author on a paper describing the work that has been published in the Proceedings of the National Academy of Sciences.

Design insights for drones or energy harvesters

The researchers mounted the flexible membrane onto a rigid frame with edges that rotate around their axes. To help visualize the flow around the wing, they immersed their device in water mixed with polystyrene tracer particles.

“Our experiments allowed us to indirectly alter the front and back angles of the wing, so we could observe how they aligned with the flow,” says Unsteady Flow Diagnostics Lab head Karen Mulleners. “Due to the membrane’s deformation, the flow wasn’t forced to roll up into a vortex; rather, it followed the wing’s curvature naturally without separating, creating more lift.”

Gehrke says that the team’s results provide important insights for biologists as well as engineers.

“We know that bats hover and that they have deformable membrane wings. How the wing deformation affects the hovering performance is an important question, but doing experiments on live animals is not trivial. By using a simplified bio-inspired experiment, we can learn about nature’s fliers and how to build more efficient aerial vehicles.”

He explains that as drones get smaller, they are more strongly affected by small aerodynamic perturbations and unsteady gusts than larger vehicles like airplanes. Standard quadrotor drones stop working at a very small scale, so one solution could be to use the same flapping wing motions as animals to build improved versions of these flyers that can hover and carry a payload more efficiently.

The team’s findings could also be used to upgrade existing energy technologies like wind turbines, or to commercialize emerging systems like tidal harvesters that passively harness energy from the ocean’s currents. Advances in sensors and control technology, potentially combined with artificial intelligence, could enable the precise control required to regulate the deformation of flexible membrane wings and adapt the performance of such flyers to varying weather conditions or flight missions.

Karen Mulleners with her lab's flexible membrane wing © Alain Herzog

Credit

Alain Herzog

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2410833121 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Highly deformable flapping membrane wings suppress the leading edge vortex in hover to perform better

Article Publication Date

28-Jan-2025

Freshwater alga could be the next superfood that feeds the world

 News Release 30-Jan-2025

University of Birmingha

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A green alga that grows in lakes and rivers could be the next ‘superfood’ - helping scientists to tackle global food security challenges while promoting environmental sustainability, a new study reveals.

Chlorella Vulgaris is a freshwater microalga rich in protein, lipids, carbohydrates, vitamins, and minerals. Unlike conventional agriculture, which requires extensive land and water resources, it can be cultivated sustainably with minimal environmental footprint.

The microalga can be incorporated into food products to enhance their nutritional value. With its antioxidant properties, immune support, and detoxifying effects, Chlorella is a promising nutraceutical ingredient.

Publishing their findings in the Journal of Food Science, scientists at the University of Birmingham believe that, while Chlorella holds immense promise, challenges remain in optimizing large-scale production and improving consumer acceptance.

The researchers emphasize the need for advancements in cultivation techniques, processing methods, and sensory improvements to enhance its appeal.

Co-author Dr Helen Onyeaka commented: “As consumer interest in health-conscious and eco-friendly products grows, Chlorella Vulgaris could be one of the superfoods that redefine the future of food innovation. Our study underscores the critical role of applied research in addressing global food security challenges while promoting environmental sustainability.

“We found that Chlorella not only meets growing demand for sustainable food sources but also offers substantial health and nutrition benefits. By overcoming production challenges through technological advancements, we can pave the way for Chlorella’s widespread adoption.”

Chlorella has been used as a food supplement, available in powder and tablet forms, and adding the substance to food products can enhance their taste, texture, and appearance. However, the researchers note that overcoming existing challenges and optimising production methods will be crucial for the microalga’s successful adoption and widespread use in the food industry.

The scientists recommend that future research should focus on improving strains, developing efficient cultivation systems, and addressing issues to fully realize Chlorella's potential as a sustainable and nutritious food source.

Their study recommends that industrialising Chlorella production involve the development of new culture systems to increase yield and reduce costs – these processes should involve different bioreactors, light and nutrient adjustments, and sterile confinements.

Techniques like mechanical milling, enzyme treatment, and ultrasonication can increase nutrient bioavailability, while pulsed electric fields may enhance digestibility economically. Sensory evaluations and consumer testing are necessary to mask unwanted tastes. Increasing awareness and developing sustainable production methods can expand Chlorella's use in the food industry, improving product quality, safety, and sustainability.

A nutrient-dense alternative to traditional food sources, Chlorella boasts high levels of protein (43–58% dry weight), lipids (5–58%), carbohydrates (12–55%), and essential vitamins and minerals such as vitamin B, calcium, and magnesium.

Beyond its nutritional value, C. vulgaris offers significant environmental advantages, helping to capture carbon dioxide and cleanse wastewater, aligning with global sustainability goals.

Health benefits include anti-tumour properties, potential for preventing Alzheimer's disease, and positive effects on major depressive disorder.

ENDS

Notes to editor:

• The University of Birmingham is ranked amongst the world’s top 100 universities institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 8,000 international students from over 150 countries.
• ‘Chlorella vulgaris as a food substitute: Applications and benefits in the food industry’ - Chiao-An Wang, Helen Onyeaka, Taghi Miri, and Fakhteh Soltani is published by the Journal of Food Science.

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Journal

Journal of Food Science

Method of Research

Literature review

Subject of Research

Cells

Article Title

Chlorella vulgaris as a food substitute: Applications and benefits in the food industry

 

New technology tracks dairy cows for improved health and productivity

Researchers develop a method to track dairy cows across a barn with multi-camera systems, improving accuracy

Tokyo University of Science

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This multi-camera system tracks dairy cows using location data instead of image features, ensuring more reliable health monitoring and barn management

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Credit: Yota Yamamoto from Tokyo University of Science

As dairy farmers dwindle every year, the demand for high-quality milk remains steadfast, driving a surge in dairy farming. Although this shift improves efficiency, it makes managing the health of individual cows more challenging. Effective health management has thereby become a critical issue in the dairy industry. Early detection of abnormalities, swift diagnosis, prevention of disease spread, and maintaining proper breeding cycles are essential for desirable and stable milk production.

While there are invasive methods, like using mechanical devices attached to dairy cows for health monitoring, non-intrusive and non-contact techniques are preferred. These methods are less stressful for the cows, as they do not require any physical attachments, making them more suitable for everyday use on farms. These include advanced deep learning methods, such as camera-based tracking and image analysis. This approach is based on the idea that dairy cows often exhibit unusual behaviors and movement patterns due to illness, diseases, the estrus cycle, stress, or anxiety. By tracking individual movements using cameras—such as walking patterns, visits to feeding stations, and water consumption frequency—farmers can analyze cow behavior, enabling early prediction of diseases or health issues.

A team of researchers from Tokyo University of Science (TUS), Japan, led by Assistant Professor Yota Yamamoto from the Department of Information and Computer Technology, Faculty of Engineering, along with Mr. Kazuhiro Akizawa, Mr. Shunpei Aou, and Professor Yukinobu Taniguchi, has developed a novel location-based method using a multi-camera system to track cows across an entire barn. Their findings were made available online on December 4, 2024, and will be published in Volume 229 of Computers and Electronics in Agriculture on February 1, 2025.

The proposed method for tracking dairy cows in barns relies on location information rather than complicated image patterns. Dr. Yamamoto explains the advancements of their technique, “This is the first attempt to track dairy cows across an entire barn using multi-camera systems. While previous studies have used multiple cameras to track different species of cows, each camera typically tracks cows individually, often the same cow as a different one across cameras. Although some methods enable consistent tracking across cameras, they have been limited to two or three cameras covering only a portion of the barn.”

The system relies on overlapping camera views to accurately and consistently track dairy cows as they move from one camera to another, enabling seamless tracking across multiple cameras. By carefully managing the number of cameras and their fields of view, the system can minimize the negative effects of obstacles like walls or pillars, which can cause fragmented camera overlaps in barns with complex layouts. This approach overcomes common challenges, such as the cows’ speckled fur patterns and distortions caused by camera lenses, which often make traditional tracking methods less accurate.

In tests using video footage of cows moving closely together in a barn, this method achieved about 90% accuracy in tracking the cows, measured through Multi-Object Tracking Accuracy, and around 80% Identification F1 score for identifying each individual cow. This marks a significant improvement over conventional methods, which struggled with accuracy, especially in crowded or complex barn environments. It also performs well in different situations, whether the cows are moving slowly or standing still, and also addressed the challenge of cows lying down by adjusting the cow height parameter to 0.9 meters, lower than a standing cow's height. This adjustment improved tracking accuracy despite posture changes.

“This method enables optimal management and round-the-clock health monitoring of dairy cows, ensuring high-quality milk production at a reasonable price,” says Dr. Yamamoto. In the future, the team plans to automate the camera setup process to simplify and speed up the installation of the system in various barns. They also aim to enhance the system’s ability to detect dairy cows that may be showing signs of illness or other health issues, helping farmers monitor and manage the health of their herds more efficiently.

 

***

 

Reference                       
DOI: 10.1016/j.compag.2024.109668

 

 

About The Tokyo University of Science
Tokyo University of Science (TUS) is a well-known and respected university, and the largest science-specialized private research university in Japan, with four campuses in central Tokyo and its suburbs and in Hokkaido. Established in 1881, the university has continually contributed to Japan's development in science through inculcating the love for science in researchers, technicians, and educators.

With a mission of “Creating science and technology for the harmonious development of nature, human beings, and society,” TUS has undertaken a wide range of research from basic to applied science. TUS has embraced a multidisciplinary approach to research and undertaken intensive study in some of today's most vital fields. TUS is a meritocracy where the best in science is recognized and nurtured. It is the only private university in Japan that has produced a Nobel Prize winner and the only private university in Asia to produce Nobel Prize winners within the natural sciences field.

Website: https://www.tus.ac.jp/en/mediarelations/

 

About Assistant Professor Yota Yamamoto from Tokyo University of Science
Yota Yamamoto is an Assistant Professor at the Department of Information and Computer Technology, Faculty of Engineering, at Tokyo University of Science. He earned his Ph.D. in Engineering from Chiba University Graduate School of Science and Engineering. His research interests include high-performance computing, special-purpose computers, FPGA, GPGPU, machine learning, image processing, holography, three-dimensional displays, and three-dimensional measurements. Dr. Yamamoto has authored over 20 papers in these fields, which have collectively been cited more than 300 times.

 

Funding information
Financial support was provided by Tsuchiya Manufacturing. Co. Ltd.

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Journal

Computers and Electronics in Agriculture

DOI

10.1016/j.compag.2024.109668 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Entire-barn dairy cow tracking framework for multi-camera systems

Article Publication Date

1-Feb-2025

COI Statement

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yukinobu Taniguchi reports financial support was provided by Tsuchiya Manufacturing. Co. Ltd. Other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

 

Pharmacy personnel report declining patient safety climate

University of Gothenburg

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Christina Ljungberg Persson, Sahlgrenska Academy at the University of Gothenburg.

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Credit: Photo by Malin Arnesson

Swedish pharmacy personnel report a deteriorating climate as regards patient safety, according to a study from the University of Gothenburg. Just under four in ten have a positive opinion of their working conditions.

The aim of the study, published in the journal BMJ Open, was to evaluate the patient safety climate among pharmacists at Swedish pharmacies and to compare the outcome with historical data. The group of pharmacists includes pharmacists and prescriptionists.

The patient safety climate was analyzed in two surveys, conducted in 2008 and 2022, in which all pharmacy personnel in Sweden were able to participate. The responses were processed anonymously without any links to employers.

Between the first and second surveys, the Swedish pharmacy market was deregulated. In 2009, the state monopoly came to an end and other stakeholders were able to pursue the retail sale of prescription and non-prescription medicines.

Lower ratings for working conditions

Now that the researchers have analyzed the 2022 survey and compared the outcome to 2008, almost all the variables studied have seen a decline. In the more recent survey, pharmacists give teamwork, safety climate, job satisfaction, management, and working conditions lower ratings.

Most affected is working conditions, with only 37 percent of pharmacists having a positive outlook, down from 53 percent. 68 percent are positive about the safety climate, as compared to 75 percent in 2008. The only real improvement is that a higher percentage recognize signs of stress in themselves.

Responsible for the study is Christina Ljungberg Persson, pharmacist and senior lecturer in community pharmacy at Sahlgrenska Academy, University of Gothenburg:

"One interesting aspect is that managers rate the patient safety climate higher than other pharmacists at the pharmacies, which raises questions about upward communication and problem resolution within the organizations. This is not only an issue for pharmacy companies, but also for government policy."

Stress increases the risk of mistakes 

While the study does not identify the role played by deregulation, Christina Ljungberg Persson notes that the work environment has changed. The goal of increased availability for customers has resulted in more smaller pharmacies, more generous opening hours, and more solitary work.

The study was conducted in collaboration with colleagues at Åbo Akademi University in Finland, and the researchers' joint conclusion is that the patient safety climate at pharmacies in Sweden appears to have deteriorated. Returning to Christina Ljungberg Persson:

"Working conditions affect patient safety. When stressed, there are increased risks of making mistakes, reading or dispensing incorrectly, not providing enough information, or not having time to call the physician to check matters. Such things can happen when you don't have enough time or resources," she ends.
 

Fact box:

Percentage of positive responses in the Safety Attitudes Questionnaire 2022 (2008)

Teamwork: 71.8% (81.2)

Safety climate: 68.2% (75.3) 

Job satisfaction: 62.1% (78.9)

Stress recognition: 73.0% (67.6)

Perceptions of management: 53.7% (68.3)

Working conditions: 37.3% (53.3)

Number of respondents in 2022: 1,931 (response rate 41%) and in 2008: 2,738 (response rate 69%)

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Journal

BMJ Open

DOI

10.1136/bmjopen-2024-088323 

Method of Research

Survey

Subject of Research

People

Article Title

Measuring the patient safety climate in community pharmacies: an updated national survey

Article Publication Date

20-Jan-2025

COI Statement

Press photo: Christina Ljungberg Persson (photo: Malin Arnesson), download here: https://news.cision.com/se/sahlgrenska-akademin-vid-goteborgs-universitet/i/christina-ljungberg-persson-foto-malin-arnesson,c3371175

Going beyond Net Zero: University of Bath engineers and architects launch manifesto on regenerative design

University of Bath’s RENEW research center says the guidebook will help engineers and designers seeking to combat the climate crisis

University of Bath

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RENEW research centre Directors Dr Juliana Calabria-Holley, Prof Sukumar Natarajan and Dr Emma Emanuelsson with the manifesto

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Credit: University of Bath

A team of engineers, architects and researchers from the University of Bath have published a manifesto on ‘regenerative’ design and engineering, providing a guide to confronting the climate crisis and creating ‘Net Positive’ buildings, technologies and systems. 

Freely available online, RENEW: a manifesto for regenerative design and engineering, demystifies the regenerative concept and unites several existing definitions of the idea, making a case for the approach to be widely adopted by professionals in engineering, architecture, and other disciplines as well as by government and industry decision makers.  

What is ‘regenerative’ design and engineering? 

Created by members of the Centre for Regenerative Design & Engineering for a Net Positive World (known as RENEW), the manifesto defines regenerative design and engineering as ‘self-evolving net-positive solutions that renew our unity with nature’. It also details the origins of the concept, and sets out useable principles for action, as well as a framework for making change. 

Professor Sukumar Natarajan, Director of RENEW, said: “Regenerative design and engineering envisions a world where human activities restore and enhance natural systems, and create resilient, fair communities that can thrive in balance with nature, while improving standards of living. 

“We need to go beyond Net Zero, to embrace ‘Net Positive’ design, construction, manufacturing or creation of goods, if we are to deliver actual benefits to society, planet and people.” 

A framework for change 

The manifesto was developed by RENEW’s 40-plus members, who are experts in fields including place-making and architecture, water and chemical engineering and materials and composites, as well as external advisors from a range of industries. 

Dr Juliana Calabria-Holley, Co-Director of RENEW, said: "Our mission is to provide global research leadership in regenerative design and engineering, by developing solutions that don’t merely abate or mitigate problems, but co-evolve societally, culturally, ecologically and economically positive co-benefits. 

“The manifesto offers a definition, principles and a framework for regenerative design and engineering for people in those communities, but we also want it to be inclusive of all disciplines, serving as a call for collaboration to address global challenges. 

“At the core of regenerative design and engineering is the understanding that complex problems require a multidisciplinary approach. Our manifesto provides a clear definition along with practical guidance on how to begin this multifaceted journey.” 

Creating a ‘less anxious’ future 

Dr Emma Emanuelsson, also a Co-Director of the centre, added: “A recent University of Bath study, interviewing 10,000 children from across the world found that 75% think the future is frightening. Eighty-three percent said people have failed to take care of the planet. 

“We want this manifesto to help create a less anxious future for today’s young people, and for humans and nature to prosper in equal measure. 

“It’s a huge challenge but it’s also an opportunity to do something new, which is really exciting. This manifesto may not show us the full journey, but it does have advice and a framework to allow us to get started.” 

Six principles of regenerative design are laid out in the manifesto. They are: 

1. Reflective governance: Establish continuously evolving metrics and monitoring practices to track progress and impact. 

2. Embrace interconnectivity: Recognise that the world is intricate and interdependent. Take a holistic view accounting for the dynamic relationships between ecosystems and communities. 

3. Work as nature: Work harmoniously with and as nature. Design systems that work as part of species and ecosystem patterns, processes, and cycles. 

4. Prioritise Net Positive: Prioritise regeneration, replenishment and restoration, recovering and reusing waste to create net-positive solutions and an abundance of resources. The aim should be to repair, sustain and enrich the planet, rather than deplete its precious resources. 

5. Cultivate Resilience: Systems should be designed with a capacity to adapt, diversify and self-renew even in the face of uncertainty, change and disturbances. 

6. Transmit: Document, curate and publicise to help proliferate best practice through active discourse on a global scale. 

You can download the RENEW manifesto here.

Read more about RENEW at: https://tinyurl.com/RENEWBath  

 

ENDS 

 

RENEW: a manifesto for regenerative design and engineering, is available to download here: https://www.bath.ac.uk/publications/centre-for-regenerative-design-engineering-for-a-net-positive-world-renew-manifesto/attachments/regenerative-design-engineering-for-a-net-positive-world-centre-manifesto-2025.pdf

An image of the Directors of the RENEW research centre is available here: https://www.dropbox.com/scl/fo/am7h7p7wqnd7q8v4fxr7c/ANdofv8Qh6FJoiL-n-tOeAc?rlkey=gx2avv791z9qemqjfd7juklyr&st=4xm1nbab&dl=0

For more information or to request interviews, contact Will McManus in the University of Bath press office: wem25@bath.ac.uk / +44(0)1225 385 798. 

 

The University of Bath 

The University of Bath is one of the UK's leading universities, with a reputation for high-impact research, excellence in education, student experience and graduate prospects.  

We are ranked in the top 10 of all of the UK’s major university guides. We are also ranked among the world’s top 10% of universities, placing 150th in the QS World University Rankings 2025. Bath was rated in the world’s top 10 universities for sport in the QS World University Rankings by Subject 2024.  

Research from Bath is helping to change the world for the better. Across the University’s three Faculties and School of Management, our research is making an impact in society, leading to low-carbon living, positive digital futures, and improved health and wellbeing. Find out all about our Research with Impact: https://www.bath.ac.uk/campaigns/research-with-impact/