Thursday, October 19, 2023

Protecting polar bears is the aim of new and improved radar technology

Protecting polar bears aim of new and improved radar technology — A mother polar bear and her cubs. Credit: Kt Miller / polarbearsinternational.org

Research testing new technology to more effectively locate polar bear dens across the Arctic is showing promising results. Researchers from Simon Fraser University and Brigham Young University (BYU), collaborating with Polar Bears International, hope that improving detection tools to locate dens—which are nearly invisible and buried under snow—will help efforts to protect mother polar bears and their cubs.

Results of a pilot study aimed at improving den location in Churchill, Manitoba—using ARTEMIS Inc., an imaging system that relies on Synthetic Aperture Radar, or SAR—are published this week in the journal Ursus, just ahead of Polar Bear Week (Oct. 29–Nov. 4).

The team found that SAR increased den detection by more than 20%, or 66%, compared with the industry's current 45% accuracy rate using the aerial Forward Looking Infrared (FLIR) system as a den-detection tool.

"Our airborne imaging radar system has multi-band, interferometric, and polarization capabilities at microwave frequencies able to penetrate snow," says SFU engineering science professor Bernhard Rabus, who holds an Industrial Research Chair in Synthetic Aperture Radar. "The system can 'see' both the top snow surface, the den roof surface and inside the den cavity."

"While our method is still in its research and testing phase, an operational version is expected to be able to extrapolate from the radar signatures of live bears in the open, combined with computer modeled den cavity radar signatures, to develop a robust match filter detection for airborne multi-channel SAR data to detect polar bears reliably inside their dens."

Unlike aerial FLIR, SAR technology performs well regardless of temperature and weather conditions, which is crucial in the Arctic, thus SAR may be an effective tool to guide conservation efforts for this vulnerable and iconic species.

"This report advances Synthetic Aperture Radar as a promising method for polar bear den detection, which is critical for protecting polar bears alongside human activity," says Geoff York, senior director of research and policy at Polar Bears International. "Brigham Young University and Simon Fraser University have been invaluable research partners, and we're excited about the possibility of SAR in the Arctic as it performs well in all weather conditions."

David Long, electrical engineering professor and director of BYU's Center for Remote Sensing, noted that the research provided BYU undergraduate Capstone students "an opportunity to do original research to identify and locate polar bears using radar. This is the first time this has ever been done, and we have great confidence this can be used in the arctic areas to detect polar bears in the snow."

Denning is the most vulnerable time for polar bears, and with increased industry activity in the region, there is a need for more accurate tools that can detect polar bear dens to avoid disturbing them during this critical time.

Polar bear cubs are born blind with only a light layer of fur to protect them from the cold. They remain dependent on their mothers, living in winter dens under the snow. They are able to emerge from the den in spring when they have grown enough to withstand the harsh Arctic conditions.

A mother bear's inability to successfully raise cubs contributed to the 40% decline of the Southern Beaufort Sea subpopulation between 2000-2010. A critical part of polar bear conservation is keeping mothers and cubs safe while also addressing other threats such as climate change.

More information: Brent George et al, On evaluating the efficacy of air-borne synthetic aperture radar for detecting polar bears: A pilot study, Ursus (2023). DOI: 10.2192/URSUS-D-22-00018

Provided by Simon Fraser University Research team identifies polar bears using DNA found in paw prints

Building economic resilience in the face of crises and climate

by David Bradley, Inderscience

vietnam skyscraper — Credit: Pixabay/CC0 Public Domain

Research published in the International Journal of Sustainable Economy has looked at the interplay between climate variability and the financial health of listed companies in Vietnam with a particular focus on the impact of the COVID-19 pandemic.

The researchers, Nguyen Thi Hoa Hong, Pham Thi Mai Huong, and Nguyen Yen Linh of the Foreign Trade University in Ha Noi, Vietnam, emphasize the importance of risk management for businesses during times of combined challenges. The work could have implications for other developing nations that are particularly vulnerable to the effects of climate change and not necessarily resilient in the face of a pandemic.

The team found that there is a negative correlation between financial performance of listed companies in Vietnam and the seemingly unrelated factors of atmospheric pressure, humidity, precipitation, but also the number of COVID-19 cases. Variability in extreme weather conditions and surges in cases of this lethal and highly infectious disease led to worse financial performance and increased economic risks for many businesses in the region.

There are broad implications of the research for businesses in the developing world. The work suggests that companies should primarily adopt measures to mitigate against the impact of climate change particularly with a view to protecting themselves when global events might worsen outcomes.

Historical events such as financial crises, wars, and pandemics have already shown us that we live in an inherently uncertain world. Climate change, with its erratic weather patterns, is now adding an additional layer of complexity that not only exists alongside such uncertainties, but can exacerbate the problems those uncertainties bring.

The team suggests that companies need to take proactive steps in the face of crises and in order to protect their business and mitigate the negative impact of such crises. Measures such as investment in weather-resistant infrastructure and drainage systems are now needed as well as a deeper understanding of the putative detrimental effects of climate change.

The researchers point out that adaptation strategies ought to be developed to improve company resilience. They add that the diversification of sourcing and production and the use of improved technology for decision-making might all play important roles in coping with emerging crises in the face of climate change.

More information: Nguyen Thi Hoa Hong et al, The effects of weather variability on the performance and risk of Vietnamese listed companies: evidence from the COVID-19 pandemic, International Journal of Sustainable Economy (2023). DOI: 10.1504/IJSE.2023.134230

Provided by Inderscience Companies in Germany are adapting to the consequences of extreme weather events

New report shows the impact of long-term sentencing in California's women's prisons

by Barbra Ramos, University of California, Los Angeles

More than 4,100 people are currently serving time behind the walls of California's prisons for women. Activist Jayda Rasberry was once one of them.

"What stands out to me the most now is the lack of knowledge anybody going into the system has," Rasberry said in a new report from the University of California Sentencing Project. "And then the lack of knowledge that we're given when we're inside."

Published by the UCLA Center for the Study of Women|Streisand Center, the report presents findings from the project's inaugural study, which focuses on those who went through these prisons and aims to counter the lack of knowledge around their experiences.

Spurred on by those who served time within the California Institution for Women, an interdisciplinary group of faculty, researchers and students from different university campuses partnered with California Coalition for Women Prisoners to take a close look at the conditions and extensive impacts of long-term sentences.

"The project epitomizes the kind of community-led research that the center endeavors to advance," said Grace Hong, the Center for the Study of Women|Streisand Center's director and professor of gender studies at UCLA. "It's based on longstanding, reciprocal organizing relationships between incarcerated and formerly incarcerated people and university researchers—some of whom are themselves system-impacted."

Hong also serves as principal investigator for the project alongside Joseph Hankins, professor of anthropology at UC San Diego.

Hankins and his co-authors emphasized the importance of the research since little has been done about long-term incarceration and its effects, especially on women and trans and non-binary people—while imprisoned and after release. Various state propositions since the 1970s have also drastically changed the special circumstances needed to impose life without the possibility of parole sentences and other harsh sentencing, with more than a hundred enhancements that can be used to maximize and extend punishment.

California has the highest rate of people in women's prisons serving a life sentence, with 1 in 4 sentenced to life without parole. In addition to the California Institution for Women, the state also has the largest women's prison in the world: the Central California Women's Facility in Chowchilla.

In December 2019, the project brought together 22 participants, ranging in age from 29 to 64, for in-depth interviews and group discussions. The majority of collaborators were sentenced as youth to long terms, with 15 entering prison at the age of 25 or younger. Many who participated knew each other; some had not seen each other in decades.

All together, they had already spent more than 300 years behind bars.

In the report, the authors emphasized that sentencing "is not a singular event but a multi-faceted process that involves an array of social processes and state actors." They focused on several themes that were found in the stories and experiences of those currently and formerly incarcerated:

The criminal legal system's refusal to recognize those sentenced as a victim or survivor, ignoring the defendant's own histories of trauma when charging or sentencing them.
The many ways that opaque criminal legal procedures led to dehumanization, coercion, neglect and further trauma.
How sentencing is entangled with larger societal forces and politics, with guilt seemingly predetermined based on race, sex and gender.
The role that prison and parole authorities play in exacerbating and even further extending sentences and punishment.
The harm and violence of long-term sentencing that go beyond time served and can inflict a lifetime of trauma that may span generations.

Romarilyn Ralston is executive director of Project Rebound at Cal State Fullerton, which supports formerly incarcerated students as they seek a college education. As a longtime organizer with the California Coalition for Women Prisoners, she participated in peer interviews and a focus group.

She said it felt good to be in community, even while acknowledging she could see how some were still grappling with the trauma of their experiences.

"Formerly incarcerated women are the least served of all incarcerated populations," said Ralston, who spent 25 years in prison. "We don't have the same resources as men available to us during reentry. We survived as best as we could."

She and the other project participants hope to get the report out to as many people as possible, including policymakers and legislators as well as those who work in public health and mental health. Copies of the report are being distributed to partners of the UC Sentencing Project and various organizations that advocate for the rights of those incarcerated and prison abolition.

Future work will include both creative and scholarly efforts that continue to center the voices and experiences of those impacted by long-term sentencing. The report also outlines research questions that could lead to more studies and knowledge to support movements for decarceration and transformative social change.

Jane Dorotik, who helped start the UC Sentencing Project and whose life sentence was only overturned last year, stressed the importance of the project and its work.

"Mass incarceration has been an abysmal failed experiment that has massively harmed our society," she said. "It's time to listen to and learn from those who know the most about these failures."

Provided by University of California, Los Angeles As pandemic prison populations fell, proportion of Black prisoners rose, finds new analysis

Exploring the limits of marine burrow cohabitation

by Kyoto University

Three's company in burrows — Bonellia sp. aff. minor (green) and its burrow associates—Basterotia bonelliphila (right)

Good real estate is not easy to find, even for sea creatures. Sometimes, push comes to shove, and species resort to competition or conquering before weighing the benefits of sharing an ecosystem like housemates.

There is abundant research on live-in symbionts, which share the burrows of other organisms in sand and mud on the seabed. However, studies on burrow niches in rigid substrates, such as rocks on the seabed, have been scarce.

Now, a research team led by Kyoto University has discovered the symbiotic communities of invertebrates in dead coral gravel on the shallow, warm-temperate coast of the Kii Peninsula in western Japan. New bivalve species and sideswimmer have been found to live communally with the greenish Bonellia spoonworm.

"During our nighttime scuba dives, we searched for the ribbon-like proboscises of Bonellia sp aff minor extending out from burrow entrances," says lead author Ryutaro Goto at KyotoU's Field Science Education and Research Center.

This resembles your pet cat trying to hide in a laundry basket, but you can see its tail sticking out.

"Observing the environment with fresh eyes and from a different angle reminded me of the possible existence of unidentified creatures lurking in familiar places," adds co-author Isao Hirabayashi.

Goto's team determined from morphological and molecular analyses that two of the three symbionts—the bivalve Basterotia bonelliphila and amphipod Leucothoe bonelliae—were new to science and deserved study of their evolutionary profiles.

Dead coral rocks are critical microhabitats for various benthic infauna, such as clams and worms. However, the biotic interactions of cryptofauna—animals existing in concealed habitats—have not received the same level of attention.

"Even seemingly barren or hostile environments that are challenging to study may provide a place to call home for a diverse range of highly adaptable organisms," reflects co-author Michitaka Shimomura.

"The symbiosis among our three burrowers highlights the deep significance of community structure and biodiversity patterns of cryptofauna, suggesting the omnipresence of symbiotic relationships in the ocean," concludes Goto.

The work is published in the Zoological Journal of the Linnean Society.

More information: Ryutaro Goto et al, Living together in dead coral rocks: macrosymbiotic communities associated with Bonellia echiuran worms (Annelida: Thalassematidae: Bonelliinae), involving new commensal bivalve and amphipod species, Zoological Journal of the Linnean Society (2023). DOI: 10.1093/zoolinnean/zlad103

Journal information: Zoological Journal of the Linnean Society

Provided by Kyoto University

Shining a light on tiny, solar-powered animals

Insect researcher: Non-destructive methods are needed

by Camilla Brodam Galacho, Aarhus University

butterfly wings — Credit: CC0 Public Domain

New research has shed light on the importance of revolutionizing methods in entomology. A publication titled "The need for a (non-destructive) method revolution in entomology" has highlighted how to improve our understanding of insects without harming them.

Traditionally, insect research has involved destructive methods, killing the insects so they could be studied more closely. Now a team, led by Senior Researcher Emeritus Gábor L. Lövei from the Department of Agroecology at Aarhus University is calling for a change in approach to insect studies. He argues that research will still be able to gain in-depth insights into the world of insects by using methods that don't harm them.

"Technological advances in image processing, molecular biology and data analysis can allow us to study insects in a gentler way. Using advanced cameras and microscopes, we can now observe and analyze insects in their natural environment without harming them," he explains.

Modern techniques are less harmful

In their perspective paper, "The need for a (non-destructive) method revolution in entomology" the international team suggests a re-evaluation of the entomological toolkit to give more emphasis to nonlethal methods. These approaches allow researchers to study insect behavior, life cycles, interactions and ecosystem contributions in a precise and comprehensive way.

By combining non-destructive methods with modern computational techniques, huge amounts of data can be analyzed, and patterns can be discovered that would otherwise be impossible to observe.

The publication also emphasizes that a shift to non-destructive methods in insect research could have major benefits. It will allow us to preserve insect samples for later studies and at the same time preserve biodiversity.

"In addition, it is also more ethical to study insects without harming or killing them. We also need a more respectful approach to nature, and entomologists ought to show an example," says Gábor L. Lövei

The researchers hope that their publication will spark a movement towards a gentler approach to insect research. They call for further research and development of technologies that can support a non-destructive methodological change in entomology.

"This approach to insect science has the potential to further our understanding of arthropods and their role in the ecosystem while causing less damage to them, and this way foster more respect towards nature. By changing our approach to the study of insects, we can contribute to a more sustainable future for our planet and its many living organisms," says Gábor L. Lövei, who has spent his entire professional career studying insects.

The study is published in the journal Biological Conservation.

More information: Gábor L. Lövei et al, The need for a (non-destructive) method revolution in entomology, Biological Conservation (2023). DOI: 10.1016/j.biocon.2023.110075

Journal information: Biological Conservation

Provided by Aarhus University Insect evolution patterns confirmed using new imaging technique

GEMOLOGY

Ancient diamonds shine light on the evolution of Earth

by Wits University

The analysis of ancient, superdeep diamonds dug up from mines in Brazil and Western Africa, has exposed new processes of how continents evolved and moved during the early evolution of complex life on Earth.

These diamonds that were formed between 650 and 450 million years ago on the base of the supercontinent Gondwana, were analyzed by an international team of experts, and have shown how supercontinents such as Gondwana were formed, stabilized, and how they move around the planet.

"Superdeep diamonds are extremely rare and we now know that they can tell us a lot about the whole process of continent formation," says Dr. Karen Smit of the Wits School of Geosciences, who was part of the study. "We wanted to date these diamonds to try and understand how the earliest continents formed."

Formed millions to billions of years ago, diamonds can shine light into the darkest and oldest parts of the Earth's mantle. Continents drift across Earth's surface creating "supercontinents" and destroying them. Collectively, these migrations are known as the "supercontinent cycle" and diamonds are one of the few minerals strong enough to survive and record these ancient cycles of creation and destruction.

Supercontinents can focus deep oceanic plate subduction—the driver of plate tectonics—in very specific regions. Such deep geologic processes, especially in the past, have been very difficult to study directly because the oceanic crust is young, and the continental crust only provides a limited view of Earth's deep workings. Old diamonds offer a direct window into the deep plate tectonic engine and how it might relate to the supercontinent cycle.

By dating the tiny silicate and sulfide inclusions inside the diamonds, the team led by Dr. Suzette Timmerman of the University of Bern, Switzerland, dated the diamonds that formed 300 to 700km deep under the base of Gondwana. The goal was to trace how material was added to the keel of the supercontinent. While doing this, the team recognized a previously unknown geologic process. The research was published in Nature.

"The geochemical analyses and dating of inclusions in the diamonds, combined with existing plate tectonic models of continent migration, showed that diamonds formed at great depths beneath Gondwana when the supercontinent covered the South Pole, between 650–450 million years ago," says Smit.

The host rocks to the diamonds became buoyant during diamond formation, transporting subducted mantle material plus the diamonds. This material was added to the base of the root of Gondwana, in essence 'growing' the supercontinent from below.

"Around 120 million years ago, Gondwana started to break apart to form the present oceans such as the Atlantic. At 90 million years ago, the diamonds, carrying trapped tiny inclusions of the host rock, were brought to Earth's surface in violent volcanic eruptions."

The current locations for these volcanic eruptions are on the continental fragments of Brazil and Western Africa, two of the key components of Gondwana. Thus, the diamonds must have migrated together with different parts of the former supercontinent as it dispersed, "glued" to their base.

"This complex history of the diamonds shows that they are remarkably well-traveled, both vertically, and horizontally, within the Earth—tracing both the formation of the supercontinent and the latter stages of its evolution. The accretion of relatively young material to the roots of the continents thickens and welds together these ancient continental fragments indicating a potential new mode of continent growth."

Smit conducted the isotope analyses of sulfide inclusions at Carnegie Institution for Science. Smit is now based at the University of the Witwatersrand where she is part of a team developing a new isotope lab and methodologies so that diamond inclusion analyses can ultimately be conducted at Wits.

"We have installed the necessary equipment in 2022 and are working towards getting the highly specialized skills and equipment together so we can do this type of diamond work in South Africa, where previously it could only be done overseas," says Smit.

"We need this type of research to understand how continents evolve and move. Without continents there wouldn't be life. This research gives us insight into how continents form, and it links to how life evolved and what makes our planet, Earth, different from other planets."

More information: Suzette Timmerman, Sublithospheric diamond ages and the supercontinent cycle, Nature (2023). DOI: 10.1038/s41586-023-06662-9. www.nature.com/articles/s41586-023-06662-9

Journal information: Nature

Provided by Wits University Argyle volcano study reveals crucial third clue to finding new diamond deposits

High-quality diamonds empower narrowband deep ultraviolet photodetection

by Compuscript Ltd

A new publication in Opto-Electronic Science reports how high-quality diamonds empower narrowband deep ultraviolet photodetection.

Compared to traditional broadband detectors, narrowband detectors have a more significant demand for applications in various industrial and cutting-edge scientific research fields due to their precise spectral resolution capabilities.

Typically, there are two methods to achieve narrowband detection at specific wavelengths. The first method involves combining a broadband photodetector with bandpass filters, which is a simple and effective approach but is limited by the availability of filters for certain wavelength bands.

The second method involves designing semiconductor structures to create intrinsic narrowband photodetectors without the need for filters. This approach reduces the complexity of the detection system compared to the first method and ensures good detection/imaging quality but places higher demands on the design of materials and devices.

Intrinsic narrowband photodetectors without filters are gaining popularity in various industrial and scientific research fields, with successful applications in the visible and infrared spectral ranges in recent years. However, there have been few reports on narrowband photodetectors in the deep ultraviolet (DUV) wavelength range, which is highly demanded in fields such as optical communications, environmental monitoring, photolithography, and space exploration.

Diamond, as an ultra-wide bandgap semiconductor, possesses exceptional physical and chemical properties, making it an ideal material for deep ultraviolet photodetection. While increasing sample thickness is a common method for narrowing charge collection in other materials, it is not suitable for diamond.

Most photodetectors based on thick single-crystal diamond exhibit broadband responses due to the high mobility of carriers in diamond and carrier trapping effects. Therefore, another critical parameter for tuning the spectral response is carrier lifetime, which is considered essential for achieving narrowband photodetection. Detailed analysis of the optical and electrical properties of diamond is crucial for achieving precise photomanipulation.

The three different single-crystal diamonds studied in the article are named Diamond A, Diamond B, and Diamond C, with their dislocation densities increasing sequentially. Interestingly, devices based on Diamond A, B, and C exhibit markedly different shapes in their external quantum efficiency (EQE) spectra, with full width at half maximum (FWHM) values of 8 nm, 31 nm, and 52 nm, respectively.

Devices based on Diamond A, characterized by its low dislocation density, display an extremely narrowband response with a peak centered at approximately 228 nm. These devices demonstrate exceptionally low dark current, high detectivity (1013 Jones), and a large linear dynamic range (LDR~118 dB).

Figure 1(a) illustrates the key physical processes that occur during the photodetection in Diamond A, including optical excitation, carrier relaxation, radiative recombination, and photoconductivity under an electric field. Figure 1(b) displays the absorption spectrum of Diamond A, confirming its low density of defect states. By analyzing the differential spectrum in the inset, the bandgap of Diamond A is calculated to be approximately 5.486 eV (with an exciton binding energy of ~80 meV).

Figure 1(c) presents the photoluminescence (PL) spectrum of Diamond A excited by a 193 nm pulse, wherein an exceptionally strong emission of free excitons is observed, indicating that exciton emission is the primary recombination process under optical excitation.

The fabricated narrowband detector can be used for imaging to distinguish different light sources. Figure 2(a) displays an optical photograph of a 222 nm excimer lamp. Figure 2(b) showcases clear imaging of the device with a light source (65×22 pixels). The emission spectrum of the excimer lamp and the EQE of the device are shown in Figure 2(c), with overlapping regions.

It has been proven that 222 nm irradiation is harmless to the human body, making it suitable for surface disinfection and radiation therapy. Research related to the low-pressure mercury lamp is presented in Figure 1(d-e), including optical photographs and corresponding imaging pictures.

The spectral lines of this low-pressure mercury lamp mainly consist of 185 nm, 194 nm, and 254 nm (Figure 2[f]), with the first two generating ozone in the air, posing a health hazard, and the last one causing irreversible damage to human skin and eyes. It is commonly used for indoor germicidal disinfection. Due to only a slight overlap between these spectral lines and EQE, the mercury lamp cannot be imaged. These results indicate that the fabricated narrowband detector can effectively distinguish between the two ultraviolet light sources.

In summary, the reported Diamond A-based photodetector boasts the shortest detection wavelength and the narrowest EQE peak to date. Its potential applications have been demonstrated through preliminary imaging. In the future, the practical performance of this detector can be further improved by fabricating array devices and optimizing the device structure. On the other hand, Diamond A's narrowband response sets it apart from other diamonds, indicating that spectral response testing of diamonds is a feasible method for discerning their quality.

More information: Lemin Jia et al, 8-nm narrowband photodetection in diamonds, Opto-Electronic Science (2023). DOI: 10.29026/oes.2023.230010

Provided by Compuscript Ltd

Experts explain how diamonds are grown in a lab

A 15th century French painting depicts an ancient stone tool

by Dartmouth College

More than 500,000 years ago, our human ancestors used large, stone tools known as "Acheulean handaxes," to cut meat and wood, and dig for tubers. Often made from flint, these prehistoric oval and pear-shaped tools are flaked on both sides and have a pointed end.

Handaxes have long been a source of fascination in our social and cultural history. Prior to the Enlightenment in the 17th and 18th centuries, people thought that they were of natural origin and referred to them as "thunderstones shot from the clouds," according to texts, with the earliest records dating back to the mid-1500s.

But researchers from Dartmouth and the University of Cambridge have identified that "The Melun Diptych" (circa 1455), painted by Jean Fouquet, depicts what is likely the earliest artistic representation of an Acheulean handaxe, demonstrating that these objects had an even earlier place in the modern world. The findings are published in the Cambridge Archaeological Journal.

"The Melun Diptych" was commissioned by Étienne Chevalier, who was from Melun, France, and served as treasurer for King Charles VII of France. The diptych is comprised of two oil paintings on wood panels: "Étienne Chevalier with Saint Stephen" on the left, and "Virgin and Child Surrounded by Angels" on the right.

The researchers found that an Acheulean handaxe appears to have been represented in the left panel. In the painting, Chevalier is depicted wearing a crimson robe with his hands folded together as if he were praying while Saint Stephen, his patron saint, is standing next to him holding the New Testament as a stone object resembling a handaxe rests on top of the book. The stone object symbolizes the death by stoning of Saint Stephen, the first Christian martyr.

Fouquet is considered one of the most important French artists prior to the Renaissance given his ability to work with oil paint.

Art historians have always referred to the stone in "The Melun Diptych" as a "jagged stone" or a "large, sharp stone," but no one had ever identified it as something human made. However, Steven Kangas, a senior lecturer in the Department of Art History at Dartmouth and study co-author, had a hunch that it wasn't just a rock.

"I've known about Fouquet's painting for years and I had always thought that the stone object looked like a prehistoric tool," says Kangas. "So, this was always sort of stuck in the back of my mind, as something that I needed to pursue in the future."

That future arrived in 2021 when Kangas attended a seminar at Dartmouth about the Isimila site in Tanzania, which is famous for handaxes. The talk was delivered by Montgomery Fellow Charles Musiba, a professor of anthropology at the University of Colorado-Denver and expert on human origins in Tanzania and South Africa.

After the seminar, Kangas chatted with Musiba and Jeremy DeSilva, a professor and chair of the Department of Anthropology at Dartmouth and co-author. Upon showing them a picture of the left panel of "The Melun Diptych," the fellow professors agreed the stone object in the painting resembled a handaxe.

To investigate this further, the researchers collaborated with colleagues at the University of Cambridge, who led the analyses of the painted stone object in the diptych.

The team conducted three analyses. They investigated the overall teardrop shape of the stone object in the painting using an approach called Elliptical Fourier Analysis, which quantifies the shape of an object. They found that its shape was similar (within 95%) to other Acheulean handaxes from the region where the paintings were made.

The researchers examined the stone object's color and compared its color to that of 20 French Acheulean handaxes. Although the colors in the painting are possibly distorted by the pigment and varnishes that have been applied, the color-variation on the object's surface of yellow, brown, and red hues was consistent with other handaxe artifacts.

As the co-authors report in the study, the high level of color-variation on the surface indicates that Fouquet went to great care and detail to paint the stone object. An infrared analysis of the painting revealed both an underdrawing and an underpainting for which the stone object had clearly been reworked.

Although an artist always has artistic license when creating their work, it's possible that Fouquet may have been replicating an actual handaxe or recreating one from memory. "Fouquet seems to have taken a special interest in the stone object, probably because he had seen one that struck his attention and imagination," says Kangas.

The researchers counted the flake scars on the surface of the painted stone object. On average, they found 33 flakes on the surface, which was consistent with the average identified on 30 handaxes that were randomly selected from their French handaxe assemblages.

"The data from our shape, color, and flake scar analyses of the stone object in the painting were remarkably consistent with that of other Acheulean handaxes from where Fouquet lived," said co-author James Clark, a graduate student in the Department of Archaeology at the University of Cambridge.

Prior research has provided evidence of pre-Homo sapiens species in Europe using Acheulean handaxes, making them one of the longest-used tools and most investigated Paleolithic artifacts.

"I love this idea of connecting a handaxe—a utilitarian object that helped hominins survive half a million years ago—with a medieval French painting, which is so well-known that it's taught in introductory art history classes," says DeSilva. "From the Paleolithic Age to the Renaissance and beyond, handaxes have been—and continue to be—part of human history."

More information: Alastair Key et al, Acheulean Handaxes in Medieval France: An Earlier 'Modern' Social History for Palaeolithic Bifaces, Cambridge Archaeological Journal (2023). DOI: 10.1017/S0959774323000252

Journal information: Cambridge Archaeological Journal

Provided by Dartmouth College Obsidian handaxe-making workshop from 1.2 million years ago discovered in Ethiopia

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