Breakthrough in clean energy: Scientists pioneer novel heat-to-electricity conversion

Researchers demonstrated for the first time transverse thermoelectric conversion in the semimetal WSi2, leading to more efficient thermoelectric devices

Tokyo University of Science

 

image: 

This paper is the first direct demonstration of the transverse thermoelectric generation in WSi2, and the results could pave the way for more efficient thermoelectric devices.

view more 

Credit: Ryuji Okazaki from Tokyo University of Science, Japan

Thermoelectric materials, which convert heat into electricity, are valuable tools for capturing waste heat and turning it into usable electricity. These materials are especially useful in industries and vehicles where engines produce a lot of waste heat, improving energy efficiency by converting it into additional power. They also exhibit potential for portable power generation, in remote sensors and satellites where traditional power sources may be impractical.

Traditional thermoelectric devices, known as parallel thermoelectric devices, generate a voltage in the same direction as the heat flow. These devices typically use two types of parallel materials, namely p- and n-type, which generate voltages in opposite directions. By connecting them in series, a stronger voltage can be generated. However, this also leads to a greater number of contact points, which increase electrical resistance and consequently, power loss. In contrast, transverse thermoelectric devices do something unique: they generate electricity perpendicular to the heat flow. This allows them to use fewer contacts and, hence, achieve a more efficient thermoelectric conversion. Materials with “axis-dependent conduction polarity (ADCP)” or goniopolar conductors, that conduct positive charges (p-type) in one direction and negative charge (n-type) in another, are promising candidates for transverse thermoelectric devices. Unfortunately, a direct demonstration of the transverse thermoelectric effect (TTE) has been less studied—until now.

In this view, a research team from Japan, led by Associate Professor Ryuji Okazaki from the Department of Physics and Astronomy at Tokyo University of Science (TUS), including Mr. Shoya Ohsumi from TUS and Dr. Yoshiki J. Sato from Saitama University, achieved TTE in the semimetal tungsten disilicide (WSi2). Although previous studies have shown that WSi2 exhibits ADCP, its origin and the anticipated TTE have not been detected in experiments. “Transverse thermoelectric conversion is a phenomenon that is gaining attention as a new core technology for sensors capable of measuring temperature and heat flow. However, there are only a limited number of such materials, and no design guidelines have been established. This is the first direct demonstration of the transverse thermoelectric conversion in WSi2,” explains Prof. Okazaki. Their study was published online in the journal PRX Energy on November 13, 2024.

The researchers analyzed the properties of WSi2 through a combination of physical experiments and computer simulations. They measured the thermopower, electrical resistivity, and thermal conductivity of a WSi2 single crystal along its two crystallographic axes at low temperatures. They found that the ADCP of WSi2 originates from its unique electronic structure, featuring mixed-dimensional Fermi surfaces. This structure reveals that electrons and holes (positive charge carriers) exist in different dimensions. A Fermi surface is a theoretical geometrical surface that separates occupied and unoccupied electronic states of charge carriers inside a solid material. In WSi2, electrons form quasi-one-dimensional Fermi surfaces and holes form quasi-two-dimensional Fermi surfaces. These unique Fermi surfaces create direction-specific conductivity, enabling the TTE effect.

The researchers also observed variations in how these charge carriers conduct electricity from sample to sample, consistent with previous studies. Using simulations based on first principles, the researchers showed that these variations were due to differences in how charge carriers scatter due to imperfections in the crystal lattice structure of WSi2. This insight is key to fine-tuning the material and developing reliable thermoelectric devices. Further, they demonstrated direct TTE generation in WSi2 by applying a temperature difference along a specific angle relative to both crystallographic axes, resulting in a voltage perpendicular to the temperature difference.

“Our results indicate that WSi2 is a promising candidate for TTE-based devices. We hope this research will lead to the development of new sensors and the discovery of new transverse thermoelectric materials,” says Prof. Okazaki.

By elucidating the mechanism of TTE generation in WSi2, this study takes a step further toward advanced materials that can convert heat into electricity more efficiently, leading to a greener future.

 

***

Reference                     

Title of original paper: Transverse thermoelectric conversion in the mixed-dimensional semimetal WSi2

Journal: PRX Energy

DOI: https://doi.org/10.1103/PRXEnergy.3.043007

 

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 Associate Professor Ryuji Okazaki from Tokyo University of Science

Dr. Ryuji Okazaki is currently an Associate Professor at the Department of Physics and Astronomy at the Tokyo University of Science, Japan. He received his M.S. and Ph.D. degrees from Kyoto University, Japan, in 2008 and 2013, respectively. He has published over 140 articles that have received over 3,400 citations, including a feature article in the journal Applied Physics Letters. He is the recipient of the Papers of Editors’ Choice by JPSJ in 2017 from The Physical Society of Japan and the 2013 Springer Theses Award. His research is focused on correlated electron systems and condensed matter physics.

 

Funding information

This work was partly supported by JSPS KAKENHI Grant No. 22K20360, No. 22H01166, and No. 24K06945, and Research Foundation for the Electrotechnology of Chubu (REFEC, No. R-04102).

---

Journal

PRX Energy

DOI

10.1103/PRXEnergy.3.043007 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Transverse thermoelectric conversion in the mixed-dimensional semimetal WSi2

Intimidation tactics against researchers in tobacco, ultra-processed food and alcohol sectors

University of Bath

New research from the University of Bath shows researchers in the tobacco, ultra-processed food (UPF) and alcohol sectors are frequently targeted with identical intimidation tactics. The most common method used by corporations or their proxies is public discreditation.

Published in Health Promotion International, the study reveals the wide range and seriousness of these tactics used by “health harming industries” (HHIs). These actions are designed to undermine and discredit advocates and researchers who give evidence to policymakers working to improve public health through stronger regulations.

Researchers from the University of Bath collaborated with researchers at the George Washington University Milken Institute School of Public Health and Inserm to compile and review public data and reports of intimidation tactics used by the tobacco, ultra-processed food and alcohol sectors since 2000. They searched six major health and social science databases, including PubMed and Web of Science, for specific keywords like "alcohol industry," "intimidation," "threat," and "researcher" to find studies that might describe intimidation tactics.

Dr Karen A. Evans-Reeves from the University’s Department of Health and Tobacco Control Research Group explained:

We found intimidatory tactics towards advocates and researchers in every sector. Public discreditation, followed by legal threats and action, complaints, and Freedom of Information Requests were most frequently mentioned and often attributed to HHIs or their third parties.

To a lesser degree, there were also instances of surveillance, threats of and actual violence, burglary, bribery and cyberattacks. Our hope is that shining a spotlight on these highly unethical tactics may reduce their chilling effect on improving health and help researchers and advocates understand how to pre-empt and respond.

The study highlights the increasing recognition of the need for stronger regulation of UCIs. With non-communicable diseases now responsible for nearly three-quarters of global deaths, the urgency to tackle the influence of these industries has never been greater.

Previous research published in The Lancet revealed that tobacco, fossil fuels, ultra-processed foods (UPFs), and alcohol collectively contribute to approximately one-third to two-thirds of all global deaths, further highlighting the critical need for action.

Dr Karen A. Evans-Reeves said:

We found that public discreditation accounted for half of the intimidation tactics used. Academics and campaigners were publicly criticised in traditional media, social media and in public arenas such as evidentiary meetings or consultations and even on t-shirts in one incident.

The language used to discredit advocates and researchers—by corporations or their industry-linked allies—is strikingly inflammatory. They are often labelled as extremists, under-qualified, or a waste of taxpayer money. Terms like ‘extremists,’ ‘fascists,’ ‘Nazis,’ ‘zealots,’ and ‘prohibitionists’ are commonly used.

Critics of the alcohol industry are dismissed as ‘nannyists,’ while food campaigners face slurs like ‘food fascists’ or ‘gastronomical gestapo.’ Breastfeeding advocates have been mockingly called the ‘breastapo,’ accused of restricting mothers’ choices. Across sectors, academics are also branded with religiously charged insults such as ‘health jihadists’ or ‘religious fundamentalists.

Dr Evans-Reeves explained that spreading these highly misleading perceptions can hinder researchers’ and advocates ability to shape policy, as such tactics may temporarily silence, delay, or even thwart their work. Despite this, the research found that most researchers continued their work even after facing public discreditation. She said:

The dominant narrative was of perseverance – only two sources referred to staff leaving their job as a result of intimidation, although it is possible that examples of people giving up their campaigns are not so well documented. This is an area that warrants more research.

This study builds on previous work by the Tobacco Control Research Group (TCRG) at the University of Bath, which exposes intimidation in tobacco control. By shedding light on these practices, the researchers strive to create an environment where public health efforts can thrive without corporate attacks and interference.

This work was supported by the Global Public Health Institution Vital Strategies (New York, USA). Part of Dr Evans-Reeves time was also funded by Bloomberg Philanthropies through the Bloomberg Initiative to Reduce Tobacco Use. The funders had no involvement in study design, data collection, analysis, decision to publish, or manuscript preparation.

---

Journal

Health Promotion International

DOI

10.1093/heapro/daae153 

Subject of Research

People

Article Title

Intimidation against advocates and researchers in the tobacco, alcohol and ultra-processed food spaces: a review

Article Publication Date

27-Nov-2024

 

Machine-vision technology shows promise to reduce herbicide use

Cambridge University Press

 

image: 

Recent research shows machine-vision targeted spray technology can significantly reduce herbicide applications compared to traditional broadcast applications. 

 

view more 

Credit: Photo by Michael Dodde, 2023 University of Arkansas graduate assistant.

WESTMINSTER, Colorado – 26 September 2024 – Farmers and land-managers seeking to reduce their herbicide applications now have another promising option via machine-vision technology. That’s the summary from a recently published research article in Weed Technology, a journal of the Weed Science Society of America (WSSA).

“Our research showed that, on average, this technology’s targeted sprays saved a range of 28.4 to 62.4% on postemergence herbicides compared to traditional broadcast applications,” says Tristen Avent, University of Arkansas, Senior Graduate Assistant in the Crop, Soil, and Environmental Sciences Department, and corresponding author of the study. “In addition to significant opportunities to lower herbicide costs and improve profits, our research also showed that the targeted applications from machine-vision technology can be utilized to provide some soybean health benefits and improve environmental stewardship.”

In this study, researchers used John Deere’s See & Spray™ Technology to compare machine-vision targeted spray technology with traditional broadcast applications. Researchers conducted the experiments for two years in Keiser, AR, and Greenville, MS, to compare residual herbicide timings and targeted spray applications versus traditional broadcast herbicide programs in glyphosate/glufosinate/dicamba-resistant soybean.

More information about machine-vision opportunities to reduce herbicide use can be found in the article, Comparing Herbicide Application Methods with See & Spray™ Technology in Soybean. The research is featured in the Volume 38, 2024, issue of Weed Technology, a Weed Science Society of America journal, published online by Cambridge University Press.

About Weed Technology

Weed Technology is a journal of the Weed Science Society of America, a nonprofit scientific society focused on weeds and their environmental impact. Weed Technology publishes original research and scholarship in the form of peer-reviewed articles focused on understanding how weeds are managed. The journal focuses on applied aspects concerning weed management in agricultural systems, weed/crop management systems, new weed problems, new technologies for weed management, herbicides used to manage undesired vegetation, and special articles emphasizing technology transfer to improve weed control. To learn more, visit www.wssa.net.

---

Journal

Weed Technology

DOI

10.1017/wet.2024.70 

Method of Research

Experimental study

Article Title

Comparing herbicide application methods with See & Spray™ technology in soybean

Article Publication Date 25-Nov-2024

New smart agriculture technology for monitoring plants

Tohoku University

 

image: 

Sensor attached directly to the underside of a plant leaf. By attaching it to the underside, light is not obstructed, allowing for accurate measurements. Data observed outdoors can be viewed in real-time from a terminal. 

view more 

Credit: ©Kohzuma and Miyamoto

With growing concerns over climate change and overpopulation, we urgently need to boost agricultural productivity. With the goal of creating a way to easily tell whether a plant is thriving or dying, a leaf-mounted sensor was created by researchers at Tohoku University. This small but mighty technology could help improve crop yields and resource management in order to meet ever-growing demands.

Extreme weather events like heatwaves, heavy rain, and droughts stress plants, which can reduce crop yields and threaten the long-term health of our farms, forests, and biodiversity. There is an unmet need to monitor precisely how plants respond to these changes. While drones and aircrafts have improved plant monitoring from above, they only capture more macro, surface-level information. They also need adjustments to be able to track plants accurately over time. Other small sensors that can capture changes at the individual plant level are inconvenient since they often require on-site personnel to install and manually check each sensor.

"The traditional methods may work well for some purposes, but they are difficult to operate and quite expensive," explains Kaori Kohzuma, "In order to continuously monitor small changes, we needed a new solution."

To address these issues, a team of researchers developed a novel sensor that attaches directly to the underside of plant leaves. This small device uses a spectroscopic sensor and light source to measure leaf color without blocking sunlight, and it can track changes in the same spot over time. Powered by a battery, with Wi-Fi data transfer and waterproofing, the sensor can work outdoors for over a month, allowing for extended data collection.

"Smart agriculture is a huge time-saver," says Ko-ichiro Miyamoto, "Farmers don't have time to manually check every single plant. This sensor is able to provide fine-tuned readings for what's going on in real time. Then, they can react accordingly to areas where plants are experiencing high levels of stress."

This sensor performed well when compared with a commercial spectrometer on about 90 leaves from 30 different plant species. It accurately distinguished colors across seven out of its eight detectable wavelengths, and its readings at 620 nm were highly similar to commercial chlorophyll meters. Further tests with a stress-sensitive Arabidopsis thaliana mutant showed that changes at 550 nm in the sensor's readings matched the plant's stress responses, which aligned with the commonly used Photochemical Reflectance Index (PRI).

In an outdoor trial to test performance under real life conditions, they attached the sensor to birch leaves to track changes in leaf color during autumn, leaf fall, and aging over two weeks. They were able to observe a decrease in chlorophyll (an indicator of plant stress) and how the plant's response fluctuated with sunlight intensity.

"This affordable sensor is a promising tool for accurately monitoring plant health and stress through leaf color and light reflection data. Its low cost makes it possible to place multiple sensors across various locations, creating a network for simultaneous monitoring in many spots," summarizes Kohzuma.

This smart diagnosis technology allows for support to be provided in the areas it's needed most. This sensor could be used widely in smart farming, forest health studies, and other areas where detailed plant health tracking is important.

The research was published in Sensing and Bio-Sensing Research on September 24, 2024.

---

Journal

Sensing and Bio-Sensing Research

DOI

10.1016/j.sbsr.2024.100688 

Article Title

Analysis of plant physiological responses based on leaf color changes through the development and application of a wireless plant sensor

 ZOONOSIS

Wild boars could be a potential source of hepatitis E transmission to humans in the Barcelona metropolitan area

University of Barcelona team detects a close molecular similarity between the hepatitis E virus strains of wild boar and humans in this area

University of Barcelona

 

image: 

From left to right, the experts Maria I. Costafreda, Marc López-Roig, Jordi Serra-Cobo and Abir Monastiri at the Faculty of Biology of the University of Barcelona.

view more 

Credit: UNIVERSITY OF BARCELONA

Over the last few decades, wild boar populations have increased in the urban areas of Barcelona and in other parts of Catalonia. This wild animal is an important reservoir of the hepatitis E virus, the disease causative agent that affects more than 20 million people every year, according to the World Health Organization (WHO). Now, a team from the Faculty of Biology, the Institute for Research on Biodiversity (IRBio) of the University of Barcelona and the Faculty of Veterinary Medicine of the Universitat Autònoma de Barcelona (UAB) has identified a relevant molecular similarity between the hepatitis E virus (HEV) strains of wild boars in the metropolitan area of Barcelona and the citizens of this area. According to the researchers, these data suggest that these animals could be a source of human hepatitis E infections in the metropolitan region.

Jordi Serra-Cobo, lecturer at the UB’s Faculty of Biology and researcher at IRBio, has co-led the study with Maria Isabel Costafreda, lecturer at the Department of Genetics, Microbiology and Statistics, and researcher at the UB Nutrition and Food Safety Institute (INSA) and the Liver and Digestive Diseases Networking Biomedical Research Centre (CIBEREHD).  Jordi Serra-Cobo warns that “the results should serve to take preventive measures and be watchful against possible transmission of the hepatitis E virus from wild boars to the citizens of the Barcelona metropolitan area”. The study, published in Science of The Total Environment, also involved Abir Monastiri and Marc López-Roig (IRBio), and Maria Costafreda, along with other researchers from the Banc de Sang i Teixits (Blood and Tissue Bank of Catalonia), the Vall d’Hebron Research Institute (VHIR), the University of Lleida and the Wildlife Ecopathology Service (UAB).

An endemic virus in the wild boar population

The metropolitan area of Barcelona is made up of thirty-six municipalities, spread over 636 km2 and populated by around 3.2 million people. This area, which includes the Collserola natural park — a peri-urban Mediterranean forest of 8,000 hectares, surrounded by urban centres — has a wild boar population density of between five and fifteen individuals per square kilometre.

In the study, the researchers analysed the faeces of 312 wild boars collected in this region between 2016 and 2021, seven of which tested positive for the presence of the virus. The comparison of these samples, together with six additional samples from a previous study, has made it possible to establish “a close phylogenetic relationship” — that is, evolutionary kinship and genetic similarity — with the HEV strains from blood donors in this area. Serra-Cobo, a member of the UB’s Department of Evolutionary Biology, Ecology and Environmental Sciences, notes that “all the isolated viruses were classified within genotype 3 of HEV”.

Moreover, the wild boar samples with the virus belonged to non-adult individuals, which, according to the researchers, indicates the endemic — that is, habitual and permanent — maintenance of HEV in the wild boar population of the metropolitan area by young individuals. In this sense, they explain that “the lack of HEV detection in adult wild boars suggests that young animals are exposed to infection by the virus in the first years of life, while adults have already overcome the infection and are protected from reinfection”. “This suggests that the virus is endemic in the wild boar population in this region”, add the researchers.

A global public health problem

The growing presence of wild boars in the urban areas of Barcelona (but also in other cities such as Lugo, Rome, Berlin, Genoa or Hong Kong) is mainly due to factors such as the loss of natural habitats induced by human activities. “Given that the synurbization — the presence and adaptation of wild boar in urbanized environments — of wild boar is a global phenomenon, which is increasing and expanding, the results of this study should be useful to develop and establish programmes for monitoring, surveillance and, eventually, control of HEV both in the metropolitan area of Barcelona and in other urban areas of the world”, says Serra-Cobo.

In the article, the experts explain that “although most human cases of hepatitis E are mild, HEV infection causes approximately 50,000 human deaths each year, and is particularly serious in pregnant women, with mortality rates of up to 30%, and can be transmitted to infants”.

Prevention and information measures

Among the measures to prevent transmission of the hepatitis E virus to the public, the researchers stress the importance of avoiding “contact with wild boars, as well as not eating their raw or undercooked meat”. In cases where contact has occurred, such as with hunters or forestry agents, they recommend washing hands with soap and water. “This practice removes the lipid envelope of the virus and inactivates it”, they note.

They also highlight other measures related to pets. “Wild boars can invade the streets of central Barcelona, where they find food in rubbish bins or urban gardens. These spaces are frequented by dogs and cats, which can become infected with wild boar faeces and can contribute to spreading the infection to citizens”, warns Jordi Serra-Cobo.

In this regard, they recommend preventing household pets from coming into contact with wild animal faeces and installing systems to prevent wild boars from knocking over waste containers. The researchers also note that “it is also important to tell the public about the risk factors for the transmission of hepatitis E from wild boars, either to humans or to pets”.

Long-term monitoring of wild boars

The IRBio research group at the UB has another study underway to determine the dynamics of hepatitis E virus infection in the wild boar population in the metropolitan area of Barcelona. The researcher also stresses the “fundamental importance” of a long-term follow-up and monitoring of the health status of the wild boar population, “especially at a time when the structure and functioning of ecosystems are changing at an unprecedented rate, as a result of climate change and anthropogenic factors”.

 

---

Journal

Science of The Total Environment

DOI

10.1016/j.scitotenv.2024.176871 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Endemic maintenance of human-related hepatitis E virus strains in synurbic wild boars, Barcelona Metropolitan Area, Spain

 

Shells, teeth and bones of ‘weird and wonderful organisms’ provide historical environmental clues

University of South Australia

A groundbreaking international study shows how chemical fingerprints left by “underappreciated” aquatic organisms could help scientists monitor global environmental change.

The study, led by the University of South Australia (UniSA), reveals how various understudied aquatic species act as “natural data loggers,” providing a historical record of the environment.

Lead scientist Dr Zoe Doubleday, from UniSA’s Future Industries Institute, collaborated with researchers from Canada, Croatia and the UK to synthesise hundreds of studies that analyse chemical variations in the shells, teeth, and bones of weird and wonderful organisms.

“Many aquatic organisms – like whales, seals, octopus and even algae – harbour chemical fingerprints that can give us a record of the environment over time, from historical water temperatures, pollution levels, and ecosystem health,” Dr Doubleday says. “They can also be used to predict the future.”

“Unlike traditional environmental monitoring, which can be costly and time consuming, or simply impossible, these organisms provide cheap, ready-made, archival data, which can be extracted using a scientific method called chemical sclerochronology.”

The research team compiled an extensive database of studies on “underappreciated” organisms, ranging from sponges and barnacles to marine mammals, and everything in between.

The team’s analysis has uncovered gaps in the current research landscape, highlighting previously understudied species and structures as alternative environmental indicators.

“These findings are crucial, as data on aquatic environments is both scarce and challenging to gather, especially in remote regions like the polar seas or deep oceans, both of which are sensitive to climate change,” Dr Doubleday says.

“Expanding our focus beyond traditional methods and species will allow scientists to tap into a wealth of data that’s been largely overlooked until now. It will help us to track environmental changes, species ecology, pollution and human impacts, informing conservation strategies so we can manage our ecosystems more effectively.”

“Capitalising on the wealth of chemical data in the accretionary structures of aquatic taxa: opportunities from across the tree of life” is authored by researchers from the University of South Australia; University of Toronto; Memorial University of Newfoundland and Labrador; Institute of Oceanography and Fisheries; and the University of Southampton. It is published in Limnology and Oceanography Letters.
DOI: 10.1002/lol2.10448

---

Journal

Limnology and Oceanography Letters

DOI

10.1002/lol2.10448 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Capitalising on the wealth of chemical data in the accretionary structures of aquatic taxa: opportunities from across the tree of life

 

“Genetic time machine” reveals complex chimpanzee cultures

University of Zurich

 

image: 

Education by apprenticeship in chimpanzees: One-year-old Joya watches and learns about a using toolset from her mother Jire: a stone hammer and stone anvil used to crack nuts, Bossou, Guinea, West Africa.

view more 

Credit: Tetsuro Matsuzawa

Chimpanzees are known for their remarkable intelligence and use of tools, but could their cultures also evolve over time like human cultures? A new, multidisciplinary study led by the University of Zurich suggests that some of their most advanced behaviors may have been passed down and refined through generations.

 

In recent decades, scientists have clearly demonstrated that chimpanzees, like humans, pass on complex cultures such as tool use from generation to generation. But human culture has become vastly more sophisticated, from the Stone Age to the Space Age, as new advances have been incorporated. Chimpanzee cultures haven’t changed in the same way, which suggests that only humans have the remarkable ability to build more sophisticated cultures over time.

Scientists studying chimpanzees in the wild, however, have disputed this, suggesting that some of chimpanzees’ most complex technologies, in which they use multiple tools in sequence to extract hidden food sources, were probably built on previous knowledge over time.

Tracing genetic links

“As most chimpanzee tools, such as sticks and stems, are perishable, there are few records of their history to confirm this hypothesis – unlike human cases such as the evolution of the wheel or computer technology,” says lead author Cassandra Gunasekaram from the Department of Evolutionary Anthropology at the University of Zurich.

For the new study, a team of anthropologists, primatologists, physicists and geneticists from universities and research institutions in Zurich, St. Andrews, Barcelona, Cambridge, Konstanz and Vienna joined forces to trace genetic links between chimpanzee populations over thousands of years, using new discoveries in genetics to uncover key pieces of chimpanzee cultural history in ways never before imagined.

Early stages of cumulative culture

The authors collected information on markers of genetic similarity – genetic evidence of links between different groups of chimpanzees – as well as a range of foraging behaviors previously reported to be culturally learned, from a total of 35 chimpanzee study sites across Africa. They grouped these behaviors into those that required no tools; those that required simple tools, such as using a leaf sponge to get water from a tree hole; and the most complex behaviors that relied on a toolset.

Trading toolsets across generations

“As an example of such a toolset, chimpanzees in the Congo region first use a strong stick to dig a deep tunnel through hard soil to reach an underground termite nest,” explains Gunasekaram. “Next, they make a ‘fishing’ probe by pulling a long plant stem through their teeth to form a brush-like tip, pressing it into a point and deftly threading it down the tunnel they’ve made. They then pull it out and nibble off any defending termites that have bitten into it.”

“We made the surprising discovery that it is the most complex chimpanzee technologies – the use of entire ‘toolsets’ – that are most strongly linked across now distant populations,” says corresponding author Andrea Migliano, professor of evolutionary anthropology at UZH. “This is exactly what would be predicted if these more advanced technologies were rarely invented and even less likely to be reinvented, and therefore more likely to have been transmitted between groups.”

How female migrations spread innovation

In chimpanzees, it is sexually maturing females, rather than males, who migrate to new communities to avoid inbreeding. In this way, genes are spread between neighboring groups and then further afield over the years, centuries and millennia. The study authors discovered that it would be these same female migrations that could spread any new cultural advances to communities that lacked them.

The study also showed that when both complex toolsets and their simpler versions (i.e., mostly the components of the toolsets) occur at different study sites, the genetic markers indicate that the sites were connected in the past by female migrations. This suggests that the complex versions were built cumulatively by adding to or modifying the simple ones. “These groundbreaking discoveries provide a new way to demonstrate that chimpanzees have a cumulative culture, albeit at an early stage of development,” Migliano adds.

Eight-year-old Jeje watches and learns about using a toolset from his mother Jire: a stone hammer and stone anvil used to crack nuts, Bossou, Guinea, West Africa.

Credit

Tetsuro Matsuzawa

---

Journal

Science

DOI

10.1126/science.adk3381 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Population connectivity shapes the distribution and complexity of chimpanzee cumulative culture

Article Publication Date

27-Nov-2024

Marxists.orgwww.marxists.org/archive/marx/works/1876/part-played-labour/

The Part Played by Labour in the Transition from Ape to Man

Hundreds of thousands of years – of no greater significance in the history of the earth than one second in the life of man [Engels note: A leading authority in ...