Friday, April 14, 2023

Ancient DNA reveals the multiethnic structure of Mongolia’s first nomadic empire

The Xiongnu dominated the Eurasian steppes two millennia ago and foreshadowed the rise of the Mongol Empire

Peer-Reviewed Publication

MAX PLANCK INSTITUTE FOR EVOLUTIONARY ANTHROPOLOGY

Artistic reconstruction of the Xiongnu's life 

IMAGE: THE XIONGNU BUILT A MULTIETHNIC EMPIRE ON THE MONGOLIAN STEPPE THAT WAS CONNECTED BY TRADE TO ROME, EGYPT, AND IMPERIAL CHINA. ARTIST RECONSTRUCTION OF LIFE AMONG THE XIONGNU IMPERIAL ELITE BY GALMANDAKH AMARSANAA. view more 

CREDIT: © DAIRYCULTURES PROJECT

Long obscured in the shadows of history, the world’s first nomadic empire - the Xiongnu - is at last coming into view thanks to painstaking archaeological excavations and new ancient DNA evidence. Arising on the Mongolian steppe 1,500 years before the Mongols, the Xiongnu empire grew to be one of Iron Age Asia’s most powerful political forces - ultimately stretching its reach and influence from Egypt to Rome to Imperial China. Economically grounded in animal husbandry and dairying, the Xiongnu were famously nomadic, building their empire on the backs of horses. Their proficiency at mounted warfare made them swift and formidable foes, and their legendary conflicts with Imperial China ultimately led to the construction of the Great Wall.

However, unlike their neighbors, the Xiongnu never developed a writing system, and consequently historical records about the Xiongnu have been almost entirely written and passed down by their rivals and enemies. Such accounts, largely recorded by Han Dynasty chroniclers, provide little useful information on the origins of the Xiongnu, their political rise, or their social organization. Although recent archaeogenetics studies have now traced the origins of the Xiongnu as a political entity to a sudden migration and mixing of disparate nomadic groups in northern Mongolia ca. 200 BCE, such findings have raised more questions than answers.

To better understand the inner workings of the seemingly enigmatic Xiongnu empire, an international team of researchers at the Max Planck Institutes for Evolutionary Anthropology (MPI-EVA) and Geoanthropology (MPI-GEO), Seoul National University, the University of Michigan, and Harvard University conducted an in-depth genetic investigation of two imperial elite Xiongnu cemeteries along the western frontier of the empire: an aristocratic elite cemetery at Takhiltyn Khotgor and a local elite cemetery at Shombuuzyn Belchir.

“We knew that the Xiongnu had a high degree of genetic diversity, but due to a lack of community-scale genomic data it remained unclear whether this diversity emerged from a heterogeneous patchwork of locally homogenous communities or whether local communities were themselves genetically diverse,” explains Juhyeon Lee, first author of the study and PhD student at Seoul National University. “We wanted to know how such genetic diversity was structured at different social and political scales, as well as in relation to power, wealth, and gender.”

The rise of a multiethnic empire

Researchers found that individuals within the two cemeteries exhibited extremely high genetic diversity, to a degree comparable with that found across the Xiongnu Empire as a whole. In fact, high genetic diversity and heterogeneity was present at all levels – across the empire, within individual communities, and even within individual families - confirming the characterization of the Xiongnu Empire as a multiethnic empire. However, much of this diversity was stratified by status. The lowest status individuals (interred as satellite burials of the elites, likely reflecting a servant status) exhibited the highest genetic diversity and heterogeneity, suggesting that these individuals originated from far-flung parts of the Xiongnu Empire or beyond. In contrast, local and aristocratic elites buried in wood-plank coffins within square tombs and stone ring graves exhibited lower overall genetic diversity and harbored higher proportions of eastern Eurasian ancestries, suggesting that elite status and power was concentrated among specific genetic subsets of the broader Xiongnu population. Nevertheless, even elite families appear to have used marriage to cement ties to newly incorporated groups, especially at Shombuuzyn Belchir.

“We now have a better idea of how the Xiongnu expanded their empire by incorporating disparate groups and leveraging marriage and kinship into empire building,” says senior author Dr. Choongwon Jeong, Associate Professor of Biological Sciences at Seoul National University.

Powerful women in Xiongnu society

A second major finding was that high status Xiongnu burials and elite grave goods were disproportionately associated with women, corroborating textual and archaeological evidence that Xiongnu women played especially prominent political roles in the expansion and integration of new territories along the empire’s frontier. At the aristocratic elite cemetery of Takhiltyn Khotgor, researchers found that the elite monumental tombs had been built for women, with each prominent woman flanked by a host of commoner males buried in simple graves. The women were interred in elaborate coffins with the golden sun and moon emblems of Xiongnu imperial power and one tomb even contained a team of six horses and a partial chariot. At the nearby local elite cemetery of Shombuuzyn Belchir, women likewise occupied the wealthiest and most elaborate graves, with grave goods consisting of wooden coffins, golden emblems and gilded objects, glass and faience beads, Chinese mirrors, a bronze cauldron, silk clothing, wooden carts, and more than a dozen livestock, as well as three objects conventionally associated with male horse-mounted warriors: a Chinese lacquer cup, a gilded iron belt clasp, and horse tack. Such objects and their symbolism convey the great political power of the women.

“Women held great power as agents of the Xiongnu imperial state along the frontier, often holding exclusive noble ranks, maintaining Xiongnu traditions, and engaging in both steppe power politics and the so-called Silk Road networks of exchange,” says Dr. Bryan Miller, project archaeologist and Assistant Professor of Central Asian Art & Archaeology at the University of Michigan.

Children in Xiongnu society

Genetic analysis also provided rare insights into the social roles of children in Xiongnu society. “Children received differential mortuary treatment depending upon age and sex, giving clues to the ages at which gender and status were ascribed in Xiongnu society,” says senior author Dr. Christina Warinner, Associate Professor of Anthropology at Harvard University and Group Leader at the Max Planck Institute for Evolutionary Anthropology. Researchers found, for example, that although adolescent Xiongnu boys as young as 11-12 years old were buried with a bow and arrows, in a manner resembling that of adult males, younger boys were not. This suggests that the gendered social roles of hunter and warrior were not ascribed to boys until late childhood or early adolescence.

The legacy of the Xiongnu today

Although the Xiongnu empire ultimately disintegrated in the late 1st century CE, the findings of the study point to the enduring social and cultural legacy of the Xiongnu. “Our results confirm the long-standing nomadic tradition of elite princesses playing critical roles in the political and economic life of the empires, especially in periphery regions - a tradition that began with the Xiongnu and continued more than a thousand years later under the Mongol Empire,” says Dr. Jamsranjav Bayarsaikhan, project archaeologist and Mongolian Archaeology Project: Surveying the Steppes (MAPSS) project coordinator at the Max Planck Institute for Geoanthropology. “While history has at times dismissed nomadic empires as fragile and short, their strong traditions have never been broken.”


Excavation of the Xiongnu Elite Tomb 64 containing a high status aristocratic woman at the site of Takhiltiin Khotgor, Mongolian Altai.

CREDIT

© Michel Neyroud

Archaeological excavation at the Shombuuziin Belchir Xiongnu cemetery, Mongolian Altai.

CREDIT

© J. Bayarsaikhan

Golden icons of the sun and moon, symbols of the Xiongnu, decorating the coffin found in Elite Tomb 64 at the Takhiltiin Khotgor site, Mongolian Altai.

CREDIT

© J. Bayarsaikhan

Child’s bow and arrow set from Grave 26 at the Shombuuziin Belchir cemetery.

CREDIT

© Bryan K. Miller




CTHULHU STUDIES

Tracking a new path to octopus and squid sensing capabilities

Research reveals that the octopus explores the marine environment with sensing features that are evolutionarily related to human brain receptors

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SAN DIEGO

Octopus Hunt 

VIDEO: A CALIFORNIA TWO-SPOT OCTOPUS (OCTOPUS BIMACULOIDES) USES ITS ARM SUCKERS TO SECURE A FIDDLER CRAB. RESEARCH LED BY UC SAN DIEGO (HIBBS LAB) AND HARVARD UNIVERSITY (BELLONO LAB) HAS TRACED THE EVOLUTIONARY ADAPTATIONS OF OCTOPUS AND SQUID SENSING CAPABILITIES. THE STUDIES, FEATURED ON THE COVER OF THE APRIL 13, 2023 ISSUE OF NATURE, REVEAL EVOLUTIONARY LINKS TO HUMAN BRAIN RECEPTORS. view more 

CREDIT: ANIK GREARSON AND PETER KILIAN

Along their eight arms, octopuses have highly sensitive suckers that allow methodical explorations of the seafloor as they search for nourishment in a “taste by touch” approach. Squids, on the other hand, use a much different tactic to find their next meal: patiently hiding until they ambush their prey in swift bursts.

In a unique analysis that provides a glimpse into the origin stories of new animal traits, a pair of research studies led by University of California San Diego and Harvard University scientists has traced the evolutionary adaptations of octopus and squid sensing capabilities. The studies, featured on the cover of the April 13 issue of Nature, reveal evolutionary links to human brain receptors.

Researchers with Ryan Hibbs’ newly established laboratory in the School of Biological Sciences at UC San Diego (formerly based at the University of Texas Southwestern Medical Center) and Nicholas Bellono’s lab at Harvard analyzed octopuses and squids, animals known as cephalopods, through a comprehensive lens that spanned atomic-level protein structure to the entire functional organism. They focused on sensory receptors as a key site for evolutionary innovation at the crossroads of ecology, neural processing and behavior.

By looking at the way octopuses and squids sense their marine environments, the researchers discovered new sensory receptor families and determined how they drive distinct behaviors in the environment. With cryo-electron microscopy technology, which uses cryogenic temperatures to capture biological processes and structures in unique ways, they showed that adaptations can help propel new behaviors.

“Cephalopods are well known for their intricate sensory organs, elaborate nervous systems and sophisticated behaviors that are comparable to complex vertebrates, but with radically different organization,” said Hibbs, a professor in the Department of Neurobiology. Hibbs brings expertise on the structure of a family of proteins in humans that mediate communication between brain neurons and other areas such as between neurons and muscle cells. “Cephalopods provide striking examples of convergent and divergent evolution that can be leveraged to understand the molecular basis of novelty across levels of biological organization.”

In one Nature study, the research teams described for the first time the structure of an octopus chemotactile (meaning chemical and touch) receptor, which octopus arms use for taste-by-touch exploration. These chemotactile receptors are similar to human brain and muscle neurotransmitter receptors, but are adapted through evolution to help evaluate possible food sources in the marine environment.

“In octopus, we found that these chemotactile receptors physically contact surfaces to determine whether the animal should eat a potential food source or reject it,” said Hibbs. “Through its structure, we found that these receptors are activated by greasy molecules, including steroids similar to cholesterol. With evolutionary, biophysical and behavioral analyses, we showed how strikingly novel structural adaptations facilitate the receptor’s transition from an ancestral role in neurotransmission to a new function in contact-dependent chemosensation of greasy environmental chemicals.”

The second Nature study focused on squid and their wholly different ambush strategy for capturing food. The researchers combined genetics, physiology and behavioral experiments to discover a new class of ancient chemotactile receptors and determined one structure within the class. They also conducted an evolutionary analysis to link adaptations in squid receptors to more elaborate expansions in octopus. They were then able to place chemotactile and ancestral neurotransmitter receptors on an evolutionary timeline and described how evolutionary adaptations drove the development of new behaviors.

“We discovered a new family of cell surface receptors that offer a rare lens into the evolution of sensation because they represent the most recent and only functionally tractable transition from neurotransmitter to environmental receptors across the entire animal kingdom,” said Hibbs. “Our structures of these unique cephalopod receptors lay a foundation for the mechanistic understanding of major functional transitions in deep evolutionary time and the origin of biological novelty.”

Hibbs says the pair of new studies offers an excellent example of how curiosity in interesting creatures can lead to insights important for all of biology, namely how proteins—life’s building blocks—adapt to mediate new functions and behaviors.

“These studies are a great example of what being a scientist is all about—wonder, exploration and understanding how things work,” he said.

Octopus chemotactile receptor (VIDEO)


UNIVERSITY OF CALIFORNIA - SAN DIEGO

Research led by UC San Diego and Harvard has traced the evolutionary adaptations of octopus and squid sensing capabilities. The researchers describe for the first time the structure of an octopus chemotactile receptor, which octopus arms use for taste-by-touch exploration of the seafloor.

CREDIT

Anik Grearson and Peter Kilian

2022 Tongan volcanic explosion was largest natural explosion in over a century, new study finds


Despite size, the mega-tsunami generated enormous waves, claimed few lives

Peer-Reviewed Publication

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE, ATMOSPHERIC, AND EARTH SCIENCE

2022 Tongan Volcanic Explosion Was Largest Natural Explosion in Over a Century, New Study Finds 

VIDEO: ANIMATION OF THE TSUNAMI PROPAGATION ACROSS THE TONGA ARCHIPELAGO view more 

CREDIT: STEVEN N. WARD - INSTITUTE OF GEOPHYSICS AND PLANETARY PHYSICS, UNIVERSITY OF CALIFORNIA SANTA CRUZ, U.S.A.

The 2022 eruption of a submarine volcano in Tonga was more powerful than the largest U.S. nuclear explosion, according to a new study led by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science and the Khaled bin Sultan Living Oceans Foundation.  

The 15-megaton volcanic explosion from Hunga Tonga-Hunga Ha'apai, one of the largest natural explosions in more than a century, generated a mega-tsunami with waves up to 45-meters high (148 feet) along the coast of Tonga’s Tofua Island and waves up to 17 meters (56 feet) on Tongatapu, the country’s most populated island.

In a new analysis in Science Advances, Rosenstiel School researchers used a combination of before-and-after satellite imagery, drone mapping, and field observations collected by scientists at The University of Auckland, and data from the Khaled bin Sultan Living Oceans Foundation Global Reef Expedition, to produce a tsunami simulation of the Tongan Archipelago. The results showed how the complex shallow bathymetry in the region acted as a low-velocity wave trap, capturing a more than hour-long tsunami with waves up to 85 meters (279 feet) high one minute after the initial explosion.

The submarine volcanic eruption of Hunga Tonga-Hunga Ha'apai, which forms the island chain of Tonga and is a result of the convergence of the Pacific and Indo-Australian tectonic plates, rivaled the 1883 eruption of Krakatau that killed over 36,000 people.

“Despite its size and long duration, the mega-tsumani that resulted from Hunga Tonga-Hunga Ha'apai claimed few lives,” said Sam Purkis, professor and chair of the Department of Marine Geosciences at the Rosenstiel School. “The main factors that led to this, we suggest, are the quirk of the location, the COVID-19 pandemic, and increased evaluation drills and awareness efforts carried out in Tonga in the years prior to the eruption.”

The simulation also suggested that the eruption location relative to urban centers saved Tonga from a worse outcome.

“While 2022 may have been a lucky escape, other submarine volcanoes possess the capacity to spawn a future tsunami at the same scale, said Purkis, who is also chief scientist at the Khaled bin Sultan Living Oceans Foundation “This eruption holds important lessons for both past and future tsunami in Tonga and beyond. The eruption was an excellent natural laboratory to test hypotheses and models that can be deployed elsewhere to improve future disaster preparations, and better understand similar eruptions and subsequent tsunami as preserved in antiquity and in the geologic record.”

The study, titled “The 2022 Hunga-Tonga Megatsunami: Near-Field Simulation of a Once-in-a-Century Event,” was published in the April issue of Science Advances. The authors include: Sam Purkis and Nathan Fitzpatrick from the University of Miami Rosenstiel School, Alexandra Dempsey from the Khaled bin Sultan Living Oceans Foundation; Steven Ward from the University of California, Santa Cruz; James Garvin and Dan Slayback from the NASA Goddard Space Flight Center; Shane J. Cronin from the University of Auckland and Monica Palaseanu-Lovejoy from the U.S. Geological Survey.

The study was supported by grants from the Khaled bin Sultan Living Oceans Foundation - Global Reef Expedition, NASA Goddard Space Flight Center and the University of Auckland, and the New Zealand Ministry of Business, Innovation and Employment, Endeavour Fund Project.


This image was captured by the Sentinel-1A synthetic aperture radar (SAR) satellite in VV polarization over the Tonga island archipelago on 14 January 2022 at 17:08 UTC, 13 hours after the initial eruption, and relayed to the University of Miami Rosenstiel School’s Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) facility in southwest Miami-Dade County. CSTARS performed an enhancement of the image to delineate clearly the circular wave patterns, likely internal waves, emanating from the volcano (large, bright spot on the left bottom) and diffracting around the islands and coral reefs of the Tonga archipelago as well as interacting with each other.

CREDIT

© 2022 European Space Agency – ESA, produced from ESA remote sensing data, image processed by ESA. Radiometrically enhanced by CSTARS.


About the University of Miami

The University of Miami is a private research university and academic health system with a distinct geographic capacity to connect institutions, individuals, and ideas across the hemisphere and around the world. The University’s vibrant and diverse academic community comprises 12 schools and colleges serving more than 17,000 undergraduate and graduate students in more than 180 majors and programs. Located within one of the most dynamic and multicultural cities in the world, the University is building new bridges across geographic, cultural, and intellectual borders, bringing a passion for scholarly excellence, a spirit of innovation, a respect for including and elevating diverse voices, and a commitment to tackling the challenges facing our world. Founded in the 1940’s, the Rosenstiel School of Marine and Atmospheric Science has grown into one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. www.earth.miami.edu.

Trees in savanna areas of Cerrado produce three times more bark than species in forest areas

The mechanism has resulted from evolution over millions of years to protect the buds that enable plants to survive fire. A study conducted in an environmental protection unit can contribute to strategies for mitigating the effects of climate change

Peer-Reviewed Publication

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

Trees in savanna areas of Cerrado 

IMAGE: TRANSITION BETWEEN SAVANNA AND FOREST IN CENTRAL PORTION OF CERRADO, CAVALCANTE MUNICIPALITY, GOIÁS STATE. FIRE IS PRESENT IN SAVANNA AREAS AND ABSENT IN FOREST AREAS view more 

CREDIT: MARCO ANTONIO CHIMINAZZO/UNESP

 In tropical regions of the planet, savannas and forests often coexist in the same area and are exposed to the same climate. An example is the Cerrado, a Brazilian biome that includes several types of vegetation, from broad-leaved and sclerophyllous in dense woodland or shrubland (cerrado sensu stricto) to semi-evergreen in closed-canopy forest (cerradão), as well as grassland with scattered shrubs (campo sujo) and even semi-deciduous seasonal forest. 

Areas of cerradão develop in the absence of fire, in both poor and moderately fertile soil (dystrophic to mesotrophic).

This coexistence intrigues botanists and ecologists since savannas and forests are home to different species and have different dynamics and functions. Savannas are dense and highly flammable grasslands that burn fairly frequently, with a direct impact on other types of vegetation. 

Forests, on the other hand, have a broad, mostly continuous canopy that provides shade for undergrowth, bushes and smaller trees, and prevents the growth of flammable grass.

Savanna species evolved over millions of years in the presence of fire and have thick bark to protect them. After burning, they form new branches and leaves from asexual buds called gemmae.

A study conducted at the Santa Bárbara Ecological Station, an environmental protection unit in São Paulo state, investigated how much bark is produced by savanna and forest species in the Cerrado, whether savanna species that produce more bark also protect their gemmae more effectively, and whether generalist species (occurring in both savanna and forest) produce different amounts of bark depending on the environment in which they grow. An article on the study is published in the journal Annals of Botany.

The principal investigator for the study was Alessandra Fidelis, a professor in the Department of Biodiversity at São Paulo State University’s Rio Claro Institute of Biosciences (IBRC-UNESP). 

The first author of the article is Marco Antonio Chiminazzo, a PhD candidate at IBRC-UNESP. 

The other co-authors are Aline Bombo, a postdoctoral fellow at IBRC-UNESP, and Tristan Charles-Dominique, a researcher at the Sorbonne in Paris and the University of Montpellier, both in France. 

“We observed that savanna species produce about three times as much bark as forest species, while generalist species are intermediate, producing more bark in savanna than forest areas. This ability to adjust bark production to the environment is known as phenotypic plasticity and may be a deliberate strategy. We also found that species that produce more bark protect their gemmae and internal tissues better,” Chiminazzo told Agência FAPESP.

“Our study shows that fire is an important factor for savanna-type vegetation in the Cerrado, promoting the woody species that can cope with this disturbance and couldn’t live in shady forest areas.”

The study provides evidence that strongly supports those who advocate the carefully controlled use of fire to manage the savanna areas of the Cerrado. Properly managed fire requires zoning and a timetable. Zoning establishes a mosaic framework within which to burn designated areas rotationally in accordance with the timetable.

“Plant species in the Cerrado have adapted to fire, producing thick bark and strongly protecting their gemmae. These traits, which are the result of a long evolutionary process, enable them to survive fires and regenerate after burning,” said Fidelis, who is Chiminazzo’s thesis advisor.

Remainder

Located in the municipality of Águas de Santa Bárbara, the ecological station where the study was conducted is an important native Cerrado remainder in São Paulo state and contains all the different types of savanna and forest found in the biome. “We sampled shrub and tree species from four different types of vegetation with varying frequencies of burning and light availability. We investigated the amount of bark they produce as they develop and how they protect their gemmae against the effects of fire. We then separated the species according to the environment they prefer to inhabit, forming three groups: savanna specialists, forest specialists and generalists [capable of growing in both],” Chiminazzo said.

Future research should set out to understand how and why certain species can adjust bark production, whereas others cannot, he added. “In the context of climate change and changes in fire regimes, garnering deeper knowledge of these species offers a major opportunity to understand and predict which organisms will be more or less endangered, in accordance with their ability to adapt to varying environmental conditions,” he said.

The study was supported by FAPESP via a Young Investigator Grant awarded to Fidelis. In addition, Chiminazzo received a master’s scholarship and a doctoral scholarship

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

Veganism is not health-conscious as such

Study analyses dietary and exercise behaviour of vegans

Peer-Reviewed Publication

MEDICAL UNIVERSITY OF VIENNA

Vegans are considered health-conscious both in the public and in their own perception. Researchers at the Centre for Public Health have now examined the dietary patterns and physical activity behaviour of vegans and found a discrepancy between appearance and reality in many cases. Although many vegans exercise more than the average person, the widespread consumption of industrially processed foods in this group cannot be classified as beneficial to health. The results of the study were recently published in the scientific journal "Nutrients".

The research group led by Maria Wakolbinger and Sandra Haider from MedUni Vienna's Centre for Public Health conducted an online survey of 516 people with an average age of 28 who had been vegan for at least three months when the study began. As the responses to the survey demonstrated, "being vegan is not per se synonymous with being 'healthy'", emphasises study director Maria Wakolbinger. As undisputed as the benefits of a plant-based diet for health are in science in the meantime, the degree of processing of the consumed food has to be taken into account, particularly in this category.

Cake or fruit
Against this background, the research team arrived at the distinction between a "health-conscious" and a "convenience" dietary pattern in the vegan lifestyle. Vegans with a convenience-base diet quality (53 percent) were characterised by a higher consumption of processed fish and meat alternatives, vegan savoury snacks, sauces, cakes and other sweets, convenience foods, fruit juices and refined types of grains. "The negative effects of industrially processed foods on health have now been clearly proven in studies," Maria Wakolbinger emphasises. "For people who primarily consume convenience foods, a 29 per cent higher risk of overall mortality, up to 51 per cent higher risk of overweight or obesity, 29 per cent higher risk of cardiovascular diseases and 74 per cent higher risk of type 2 diabetes mellitus have been scientifically proven".

In contrast to the convenience food group, vegans (47 per cent) who are classified as health-conscious consume more vegetables, fruit, protein and milk alternatives, potatoes, wholemeal products, vegetable oils and fats, and cook more often with fresh ingredients.

The studied vegan population also proved to be heterogeneous with regard to physical activity behaviour: "The physical activity level of vegans is higher overall than that of the average population in Austria. However, as our study illustrated, the health-conscious group is significantly more active than those who belong to the convenience food pattern," explains first author Sandra Haider.

"Pudding Veganism"
In contrast to vegetarianism, veganism is a form of plant-based nutrition in which not only meat but all food and by-products of animal origin are dispensed with. In Austria, approximately two percent of people now follow a vegan diet. The term "pudding vegetarianism" has already become established for variants of the vegetarian diet that are unfavourable to health in which, for example, many sweets are consumed instead of meat. "Accordingly, the convenience dietary pattern we identified could well be called 'pudding veganism'," Maria Wakolbinger and Sandra Haider summarise their study on raising awareness which they want to contribute in view of the booming market for ultra-processed meat and dairy substitutes. Today, vegan meat and milk alternatives generate an annual turnover of 1.7 billion Euros in Europe.

Living through high inflation increases home ownership

UC San Diego Rady School of Management Study reveals implications of today’s high inflation will have a lasting impact on housing markets

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SAN DIEGO

Figure 1 

IMAGE: FIGURE 1 view more 

CREDIT: UC SAN DIEGO

People who experience periods of high inflation are more likely to buy a home, according to a new study from the University of California San Diego’s Rady School of Management.

The paper, to be published in The Journal of Finance, uses various sources of data which reveal households that have been exposed to high inflation are more likely to invest in real estate. The study suggests many homeowners buy because they are motivated to protect themselves from possible future price hikes.

The study is the first to reveal that personal experience with inflation is a driver of home ownership.

“We think one reason people choose to buy instead of rent is because they are worried about future inflation, which may drive up both rent and house prices,” said Alex Steiny Wellsjo, study co-author and assistant professor of economics and strategy at the Rady School. “People who have lived through high inflation in the past may expect higher inflation in the future, causing them to wish they were a homeowner. This is especially true if they can finance with a fixed-rate mortgage, further protecting them from future inflation.”

Wellsjo added that the implications of the high inflation people are currently experiencing around the world will have a lasting impact on housing markets.

“Our paper suggests that cohorts living through the current inflationary period will have a higher demand for housing for years to come,” she said.

To find out how people make home ownership decisions, Wellsjo and co-author Ulrike Malmendier, a professor with a joint appointment at the Haas School of Business and economics department at UC Berkeley, conducted a novel survey of 700 homeowners in six European countries (Austria, Germany, Ireland, Italy, Portugal and Spain).

Respondents on the survey were asked: what are good reasons to buy a home, whether they have personally experienced high inflation, whether they were worried about future inflation and whether inflation impacted their own decision to buy a home.

Of those surveyed, 50% indicated that “real estate is a good investment if there is inflation.” People who had lived through high inflation were 21% more likely to be worried about inflation in the future and 74% more likely to say that inflation affected their own decision to buy a home.

The authors also used data from the European Central Bank’s Household Finance and Consumption Survey of 220,000 households across 22 European countries, which revealed that the effects of experienced inflation are large. For example, for the typical household, increasing their inflation experiences from 2% to 5.4%, would increase their likelihood of owning from 65% to 75%.

Households’ exposure to past episodes of higher or lower inflation can help to explain differences in the composition of homeownership both within and across countries.

For example, in Germany and Austria, less than half of households own a home. But 85% or more own in Lithuania, Slovakia and Croatia, countries that have histories of high inflation. Similarly, only 57% own their home in France, which has had more price stability, but 82% do in neighboring Spain—a country with a long history of inflation.

“These households with similar demographics and in similar financial situations make systematically different tenure decisions,” write Wellsjo  and Malmendier. “While financial institutions play an important role, as do house prices, housing supply and demographics, we show that economic histories experienced by potential homeowners and especially inflation experiences, strongly predict investment in housing.”

The effect of personal experiences appears to be powerful and long-lasting enough to influence even the homeownership decisions of immigrants who move to a new housing market and still respond to the inflation exposure they experienced in their home countries.

Using data from the American Community Survey, Wellsjo and Malmendier identified household heads who immigrated to the U.S. from outside the country. They were able to calculate the household’s lifetime inflation experiences during their time in their home country and in the U.S. and how that impacted their purchasing decisions after immigrating. Once again, they find that household heads who experienced higher inflation over their lifetime were more likely to be homeowners.

“We show that the relationship between prior inflation and home purchasing choices is not explained by housing market conditions, nor by indicators of current economic conditions or other economic experiences,” the authors write. “The impacts of experiencing high inflation have a long-lasting effect on home ownership.”

Gentle method allows for eco-friendly recycling of solar cells

Peer-Reviewed Publication

CHALMERS UNIVERSITY OF TECHNOLOGY

Thin-film solar cells on roof tiles 

IMAGE: THIN-FILM SOLAR CELLS ON ROOF TILES view more 

CREDIT: MIDSUMMER

By using a new method, precious metals can be efficiently recovered from thin-film solar cells. This is shown by new research from Chalmers University of Technology, Sweden. The method is also more environmentally friendly than previous methods of recycling and paves the way for more flexible and highly efficient solar cells.

Today there are two mainstream types of solar cells. The most common is silicon-based and accounts for 90 percent of the market. The other type is called thin-film solar cells which in turn uses three main sub-technologies, one of which is known as CIGS (Copper Indium Gallium Selenide), and consists of a layer of different metals, including indium and silver. Thin-film solar cells are by far the most effective of today's commercially available technologies. They can also be made bendable and adaptable, which means that they can be used in many different areas. The problem is that the demand for indium and silver is high, and increased production is accompanied by a growing amount of production waste, which contains a mixture of valuable metals and hazardous substances. Being able to separate attractive metals from other substances, therefore, becomes extremely valuable, both economically and environmentally, as they can be reused in new products.

“It is crucial to remove any contamination and recycle, so that the material becomes as clean as possible again. Until now, high heat and a large amount of chemicals have been used to succeed, which is an expensive process that is also not environmentally friendly”, says Ioanna Teknetzi, PhD student at the Department of Chemistry and Chemical Engineering, who together with Burcak Ebin and Stellan Holgersson published the new results in the journal Solar Energy Materials and Solar Cells.

Now their research shows that a more environmentally friendly recycling process can have the same outcome.

“We took into account both purity and environmentally friendly recycling conditions and studied how to separate the metals in the thin-film solar cells in acidic solutions through a much ‘kinder’ way of using a method called leaching. We also have to use chemicals, but nowhere near as much as with previous leaching methods. To check the purity of the recovered indium and silver, we also measured the concentrations of possible impurities and saw that optimisation can reduce these”, says Ioanna Teknetzi.

The researchers showed that it is possible to recover 100 percent of the silver and about 85 percent of the indium. The process takes place at room temperature without adding heat.

“It takes one day, which is slightly longer than traditional methods, but with our method, it becomes more cost-effective and better for the environment. Our hopes are that our research can be used as a reference to optimise the recycling process and pave the way for using the method on a larger scale in the future”, says Burcak Ebin.

 

The method

1. The film from the solar cell is analysed with respect to material, chemical composition, particle size and thickness. The solar cell is placed in a container with an acid solution at the desired temperature. Agitation is used to facilitate dissolution of metals in the acid solution. This process is called leaching.

2. Leaching effectiveness and chemical reactions are assessed by analysing samples taken at specific times during the leaching process. The different metals are leached at different times. This means that the process can be stopped before all the metals begin to dissolve, which in turn contributes to achieving higher purity.

3. When the leaching is complete, the desired metals are in the solution in the form of ions and can be easily purified to be reused in the manufacture of new solar cells.

 

More about the study

Valuable metal recycling from thin film CIGS solar cells by leaching under mild conditions has been published in Solar Energy Materials and Solar Cells. The authors are Ioanna Teknetzi, Burcak Ebin and Stellan Holgersson at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology. The study has been carried out at Chalmers Material Analysis Laboratory, CMAL, and the research has received funding from the Swedish Energy Agency.

 

For more information, please contact:

Ioanna Teknetzi, PhD student, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, ioanna.teknetzi@chalmers.se

Dr. Burcak Ebin, researcher, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, +46 31 772 17 29, burcak@chalmers.se

Dr. Stellan Holgersson, researcher, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, +46 31 772 28 02, stehol@chalmers.se

 

 

Caption: Thin-film solar cells are highly efficient and can be made bendable and adaptable, meaning they can be used in a wide range of areas, such as here on roof tiles. Photo of solar cells: Midsummer