Thursday, June 05, 2025

HKU professor Guy Abel collaborates on groundbreaking study to measure global migration

The University of Hong Kong

image:
Professor Guy Abel of the Department of Sociology, Faculty of Social Sciences of the University of Hong Kong, alongside researchers from Meta and Harvard University, introduces a groundbreaking approach to measuring international migration.
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Credit: The University of Hong Kong

A new study co-authored by Professor Guy Abel of the Department of Sociology, Faculty of Social Sciences of the University of Hong Kong, alongside researchers from Meta and Harvard University, introduces a groundbreaking approach to measuring international migration. Published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS), the research leverages online data to provide the most comprehensive and timely estimates of global migration flows to date.

The study, titled "Measuring Global Migration Flows Using Online Data," was conducted by Professor Abel in collaboration with Meta researchers Guanghua Chi, Eugenia Giraudy, and Mike Bailey, as well as Drew Johnston from Harvard University. Their innovative approach utilises privacy-protected records from over three billion Facebook users to estimate monthly migration flows between 181 countries, accounting for biases in social media usage to generate reliable and near-real-time insights.

Key findings from the research include:

An estimation of 39.1 million international migrants in 2022, representing 0.63% of the population in the sampled countries.
A 64% decrease in migration during the COVID-19 pandemic, followed by a rebound in 2022 to a rate 24% higher than pre-pandemic levels.
A tenfold increase in migration from Ukraine following the Russia-Ukraine war.

"This work addresses a critical gap in global migration data," said Professor Abel. "Past efforts pieced together various migration and demographic data to provide a tentative glimpse of global migration patterns. This new research takes a more direct approach, leveraging billions of anonymised digital traces to directly estimate when and where people migrate across borders. The estimates provide timely and detailed insights that can guide researchers, policymakers, and humanitarian efforts worldwide."

Access the full study and data:

Full paper: https://www.pnas.org/doi/10.1073/pnas.2409418122
Migration data: https://data.humdata.org/dataset/international-migration-flows
The New York Times article on the estimates, including an interactive data visualization: https://www.nytimes.com/interactive/2025/04/17/opinion/global-migration-facebook-data.html

For media enquiry, please contact:
Department of Sociology, Faculty of Social Sciences, HKU by email (socidept@hku.hk)

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2409418122

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Measuring global migration flows using online data

Survival of the greenest: Why world’s oldest organizations are surpassing young upstarts in environmental sustainability

Frontiers

What does it take for a company to last for centuries? Ask most business analysts, and you’ll hear about innovation, financial acumen, or strategic pivots. But new research suggests another key to organizational survival: environmental sustainability. In a study recently published in Frontiers in Organizational Psychology, an international team of researchers reveals a robust link between organizations’ longevity and their commitment to environmentally sustainable business practices. The findings challenge the assumption that younger, more agile companies are best positioned to lead on climate and environmental issues.

The study explores whether firms that have stood the test of time — some over a century old — are also those most committed to preserving the planet. It’s a timely question. As climate change accelerates and the call for corporate accountability grows louder, understanding the organizational characteristics associated with environmental responsibility is more critical than ever.

The study analyzed data from hundreds of firms including industry leaders in tech, manufacturing, and finance in the United States, Europe, the Middle East and North Africa (MENA), and Asia. Our goal was simple yet ambitious: determine whether older organizations exhibit stronger environmental sustainability performance than younger ones. To answer this, our team analyzed environmental, social, and governance (ESG) ratings drawn from multiple independent sources, including CSRHub, S&P Global, and Thomson Reuters, that evaluate companies on dimensions of climate strategy, eco-efficiency, and environmental reporting.

Standing the test of time

The results were striking. In every region examined, older organizations outperformed their younger counterparts on environmental metrics. These effects held even when accounting for company size and wealth, suggesting that longevity itself — not just financial clout — correlates with environmental stewardship. In the United States, for example, companies established more than a century ago showed markedly higher sustainability scores than those formed in the last two decades. The same pattern emerged in MENA and Asian markets. The effect was slightly less pronounced in Europe, likely due to limited availability of incorporation dates of companies in that region, rather than reflecting a substantive difference in sustainability performance.

Beyond establishing this link, our paper takes a deeper dive into why older organizations might be greener, building on evolutionary theories of organizations, resource dependence theory, and psychological frameworks like Cybernetic Trait Complexes Theory. Our central thesis: surviving over time requires adaptation—not just to markets, but to environmental and societal demands. Organizations that endure are those that have learned to navigate resource scarcity, respond to public scrutiny, and build sustainable systems into their operations. In this light, sustainability is not an add-on; it is a survival strategy.

The implications of this work extend beyond theory. One key takeaway is that sustainability is not just the domain of startups or mission-driven newcomers. Older firms, often seen as sluggish or resistant to change, may in fact be the most effective stewards of sustainability, thanks to decades of institutional knowledge, established systems, and embedded norms. These organizations are not only capable of setting long-term goals; they often have the operational discipline and stakeholder networks to see those goals through.

Green shoots of growth

Our findings also carry weight for policy and practice. Policymakers might consider designing incentives that recognize the sustainability strengths of mature organizations, while also supporting younger companies in building long-term environmental strategies. For investors, the message is equally compelling. ESG scores are increasingly used to evaluate corporate risk and resilience. If sustainability performance is a signal of adaptability and thus of long-term viability, then green credentials may offer a glimpse into a company’s staying power.

Still, we must be careful not to paint a one-sided picture. Of course, some legacy firms emerged from eras of industrial pollution and ecological harm. Nonetheless, what matters is not where these companies started but how they have evolved. Our data show that many older firms have adapted meaningfully, outperforming younger peers even in innovation-related sustainability metrics.

Perhaps most powerfully, we believe these data call for a new narrative about sustainability in business. Sustainability is not a generational rivalry. It is not a race between new and old, small and large, or East and West; it is a test of adaptation, a shared evolutionary journey where the most enduring organizations are often those that embrace sustainability as central to who they are. The climate crisis is rewriting what it means to lead in business, and in this new chapter, the champions will be not only the boldest or the strongest, but the greenest.

Journal

Frontiers in Organizational Psychology

DOI

10.3389/forgp.2025.1521537

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Survival of the Greenest: Environmental Sustainability and Longevity of Organizations

Article Publication Date

5-Jun-2025

Fungal resistance in wheat: preserving biodiversity for food security

Plant sciences

University of Zurich

Wheat leaf with yellow rust — image:
Yellow rust is a fungal disease and a significant threat to the worldwide wheat production. Yellow stripes on the wheat leaves are typical of an infestation.
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Credit: Katharina Jung, University of Zurich

Wheat production is threatened by a major fungal disease: yellow rust. Researchers at the University of Zurich have found traditional wheat varieties from Asia that harbor several resistance-conferring genes. They may serve as a durable source of yellow rust resistance in commercial varieties in the future, highlighting the importance of genetic diversity for food security.

Yellow rust, also known as stripe rust, is caused by a fungal pathogen named Puccinia striiformis f. sp. tritici. The plant disease affects around 88% of global bread wheat production and is one of the most devastating threats to wheat yields. New strategies against the fungus are therefore urgently needed. An international team headed by researchers at the University of Zurich (UZH) has now discovered two genomic regions in traditional wheat varieties from Asia which confer resistance to the disease. “If such genes can be transferred to commercial wheat varieties, they could be important in combating yellow rust,” says Kentaro Shimizu, professor at the UZH Department of Evolutionary Biology and Environmental Studies, who is responsible for a new study on the subject.

Genetic diversity of wheat local varieties

For decades, targeted breeding of wheat focused on developing high-yielding varieties. While these modern varieties helped feed the world, their limited genetic diversity led to increased vulnerability to threats such as pests, diseases and extreme climates. In contrast to modern varieties, traditional wheat varieties have been maintained by local farmers in different regions of the world and therefore less impacted by the loss of genetic diversity. Traditional varieties from Asia appeared particularly promising, for they have been underexplored despite being a potential reservoir of genetic diversity with higher disease resistance.

During her PhD in Shimizu’s team, Katharina Jung conducted the research on wheat yellow rust resistance in collaboration with the International Maize and Wheat Improvement Center (CIMMYT) in Mexico and the Kyoto University in Japan. Jung screened both traditional and modern varieties from Japan, China, Nepal and Pakistan. First, she identified yellow rust resistant wheat plants in large-scale field experiments in Reckenholz, Switzerland, and at CIMMYT, Mexico. Then, she located genomic regions that contribute to yellow rust resistance, so-called quantitative trait loci.

Targeted search for novel yellow rust resistances

Jung uncovered two potentially new genomic regions related to yellow rust resistance: One is specific to a traditional variety from Nepal, while the other is more broadly distributed across traditional varieties from Nepal, Pakistan, and China in the southern Himalayan area. “Interestingly, the southern Himalayan area is believed to be the origin of the yellow rust pathogen itself. Taken together with our findings, we hypothesize that traditional varieties from this area might harbor unique and stable resistances to yellow rust,” says Jung. A more targeted search for novel yellow rust resistances from this area could potentially provide long-lasting protection against a wide range of pathogen strains.

Safeguarding local varieties and farming practices

The new results underscore the importance of conserving genetic diversity and traditional varieties in wheat to combat diseases and other threats. Farmers have cultivated and maintained these traditional varieties in different parts of the world for generations, which is of great value for future food security. “Traditional varieties must be preserved both in gene banks and in farmers’ fields before they are lost forever. Their use and benefit-sharing should be done in close collaboration with local communities, as their knowledge and practice have paved the way to the genetic diversity we observe today,” says Jung.

Kyoto University: important UZH collaboration partner in Asia

The wheat varieties provided by Kyoto University were essential for this project. “I cannot emphasize enough how valuable such a collaboration is in making scientific progress,” says Kentaro Shimizu. The UZH Global Funding Scheme, managed by the Global Affairs office, supported this project. Collaborations between UZH and Kyoto University have existed for many years. In 2020, the alliance between two institutions was converted into a Strategic Partnership.

If it were possible to utilize the resistance genes from local Asian varieties in breeding modern wheat varieties, crop losses could be reduced in the future.

Credit

Katharina Jung, University of Zurich

Several wheat varieties with differently shaped ears.

Credit

César Rodríguez, Mexico

Journal

Theoretical and Applied Genetics

DOI

10.1007/s00122-025-04886-z

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Unveiling yellow rust resistance in the near‐Himalayan region: insights from a nested association mapping study

Article Publication Date

5-Jun-2025

’Round midnight: Late-night romance among medaka in near natural setting

Continuous 24-hour observations clarify time these fish engage in courtship, spawning

Osaka Metropolitan University

Late-night activity — image:
Infrared camera footage shows medaka fish spawning at midnight.
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Credit: Osaka Metropolitan University

Osaka Metropolitan University researchers have gained clearer insights into the natural behavior of medaka, small fish that are useful as model organisms in the lab.

Specially Appointed Dr. Yuki Kondo and Professor Satoshi Awata of the Graduate School of Science conducted continuous 24-hour observations of medaka raised in an environment close to their natural habitat and verified when the fish begin their reproductive behavior.

Medaka spawning behavior in a natural environment begins around 1 a.m. and peaks between 2 a.m. and 4 a.m. In addition, courtship behavior was frequently observed between 2 a.m. and 5 a.m. Many other behaviors also started during the late-night hours.

“These discoveries will lead to a review of the experimental conditions for medaka as a model organism and demonstrate the importance of information on the natural ecology of such organisms,” stated Dr. Kondo.

###

About OMU

Established in Osaka as one of the largest public universities in Japan, Osaka Metropolitan University is committed to shaping the future of society through “Convergence of Knowledge” and the promotion of world-class research. For more research news, visit https://www.omu.ac.jp/en/ and follow us on social media: X, Facebook, Instagram, LinkedIn.

Journal

Scientific Reports

DOI

10.1038/s41598-025-01037-8

Method of Research

Observational study

Subject of Research

Animals

Article Title

Courtship and spawning behaviour of medaka in a semi-outdoor environment initiating at midnight

Why seismic waves spontaneously race inside the earth

ETH Zurich

Earthquakes, volcanic eruptions, shifting tectonic plates - these are all signs that our planet is alive. But what is revealed deep inside the earth surprises laymen and scientists alike: Almost 3000 kilometres below the Earth's surface, solid rock is flowing that is neither liquid, like lava, nor brittle like solid rock. This is shown by a new study by geoscientists led by Motohiko Murakami, Professor of Experimental Mineral Physics at ETH Zurich. The study has just been published in the journal Communications Earth & Environment.

Half a century of guesswork

For over 50 years, researchers have been puzzling over a strange zone deep inside the earth - the so-called D” layer, around 2700 kilometres beneath our feet. Earthquake waves suddenly behave differently there: their speed jumps as if they were travelling through a different material. What exactly happens at that layer of the mantle has been unclear for a long time, until now.

In 2004, Murakami, who has been a professor at ETH Zurich since 2017, discovered that perovskite, the main mineral of the Earth's lower mantle, transforms into a new mineral near the D” layer under extreme pressure and very high temperatures - so-called “post-perovskite”.

The researchers assumed that this change explained the strange acceleration of the seismic waves. But that was not the full story. In 2007, Murakami and colleagues found new evidence that the phase change of perovskite alone is not enough to accelerate earthquake waves.

Using a sophisticated computer model, they finally discovered something important: depending on the direction in which the post-perovskite crystals point, the hardness of the mineral changes. Only when all the crystals of the mineral point in the same direction in the model are the seismic waves accelerated - as can be observed in the D” layer at a depth of 2700 kilometres.

In an unusual laboratory experiment at ETH Zurich, Murakami has now proven that post-perovskite crystals align themselves in the identical direction under enormous pressure and extreme temperatures. To do this, the researchers measured the speed of seismic waves in their experiment and were also able to reproduce the jump that occurs at the D” layer in the laboratory. “We have finally found the last piece of the puzzle,” says Murakami.

Mantle flow aligns crystals

The big question is: what makes these crystals line up? The answer is that solid mantle rock that flows horizontally along the lower edge of the Earth's mantle. Researchers have long suspected that this movement - a kind of convection like boiling water - must exist but have never been able to prove it directly.

A new chapter in Earth research begins

Murakami and his colleagues have now also demonstrated experimentally that mantle convection of solid rock is present at the boundary between the core and the Earth's mantle, i.e. that solid - not liquid - rock flows slowly but steadily at this depth. “This discovery not only solves the mystery of the D” layer but also opens a window into the dynamics in the depths of the Earth,” Murakami explains.

It is not only a milestone, but also a turning point. The assumption that solid rock flows has been transformed from a theory into a certainty. “Our discovery shows that the Earth is not only active on the surface, but is also in motion deep inside,” says the ETH professor.

With this knowledge, researchers can now begin to map the currents in the Earth's deepest interior and thus visualise the invisible motor that drives volcanoes, tectonic plates, and perhaps even the Earth's magnetic field.

Journal

Communications Earth & Environment

DOI

10.1038/s43247-025-02383-1

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

The texture of the post-perovskite phase controls the characteristics of the D” seismic discontinuity