Model connects animal movement and population dynamics

Brazilian-German collaboration closes gap in theoretical ecology

Helmholtz-Zentrum Dresden-Rossendorf

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For planning animal conservation measures, it is vital to know where endangered species live and how they interact. Ecologists are successfully using tracking technology to learn about the movements of individual animals. Yet, leveraging this knowledge to understand how entire populations change in space and time, including long-term persistence and survival chances in a given area, remains a long-standing open question in ecology. A major step toward answering this question was now achieved through a collaboration between researchers from São Paulo State University (UNESP, Brazil) and the Center for Advanced Systems Understanding (CASUS) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR): The scientists introduced a new theoretical framework that shows how individual animal movements and their home ranges shape population dynamics across space and time (Ecology Letters, DOI: 10.1111/ele.70269).

Despite decades of independent progress in population ecology and movement ecology, researchers have lacked a theoretical bridge between these two disciplines. “Ecologists have been trying to establish this link since the 1950s, when they started to characterize animal movement patterns,” says Dr. Ricardo Martinez-Garcia, head of the CASUS Young Investigator Group “Dynamics of Complex Living Systems” and senior author of the study. Classic population dynamics models, going back to Pierre François Verhulst’s work in 1838, describe how populations grow until they reach the limits imposed by available resources, such as food and space, but overlook the importance of animal movement in determining these saturation patterns. “In many cases, observed population sizes could not be explained with existing theoretical frameworks. We were confident that incorporating the movement behavior of individual animals we observe in tracking data could solve these discrepancies,” adds Martinez-Garcia.

Ecologists have long known that animals use their habitats non-uniformly and spend most of their lives within home ranges that are substantially smaller than the population range. In recent years, technological and methodological advances have provided unprecedented insight into how organisms move, including a more precise quantification of their home ranges. Central to this progress are statistical methods developed with key contributions from Prof. Justin M. Calabrese, co-author of the study and head of the Earth System Science department at CASUS. “A major innovation of our theory is that it allows the prediction of population dynamics to be based on the same animal movement model that is widely used to estimate home ranges from tracking data. This means that, under the hood, home-range estimation and population modeling can now be powered by the same engine, which gives our theory a stronger connection to data and leads to better-informed, real-world conservation recommendations,” says Calabrese.

Model incorporates interactions between more than two animals

A 2020 study led by Martinez-Garcia already linked individuals’ exact use of their home ranges, their so-called range-residency, to the frequency of interactions between two animals. It showed that encounter rates can deviate strongly from those predicted by classical models that oversimplify movement. The next logical step was moving from pairs to a larger number of animals. In this way, the theoretical framework would be able to account for demographic processes driven by cooperation, competition, reproduction and other animal interactions. But this change of scale in the study represented a significant challenge: “When we have an entire population of animals, each one will have its own movement behavior and the number of possible interactions becomes enormous very quickly,” says Rafael Menezes, a postdoctoral researcher at UNESP and former PhD student at Martinez-Garcia’s group.

The extended framework, named range-resident logistic model, manages this complexity elegantly by introducing a so-called crowding index that summarizes all relevant information about how movement shapes animal interactions. Menezes continues: “This coefficient, which can be readily calculated from animal tracking data, gives an indication of how animals in a population interact: are they avoiding each other, are they trying to spend more time close to each other, or are they somewhat indifferent?”

The direct comparison of the new and old models clearly indicates, as foreseen, a highly relevant impact of the movement data: Depending on the selected parameter conditions, population size predicted by the range-resident logistic model is sometimes twice, sometimes half the size of that predicted by the classical Verhulst equation. “A difference that can make a difference,” comments Martinez-Garcia. According to him, the new model is important when practical conservation questions are investigated, such as the impact of human infrastructure on the fate of wildlife populations. “One particular case we are currently working on is the question of what happens to a population when a new highway cuts through the animal’s habitat. Specifically, we are talking about Brazilian tapirs here. Only thanks to an accurate description of animal movements, we can quantify wildlife vehicle collisions and estimate viability of the tapir population.”

Brazilian scientist joins CASUS

Brazilian native Rafael Menezes is a postdoctoral researcher at the International Center for Theoretical Physics-South American Institute for Fundamental Research (ICTP-SAIFR), an international research center based at the Institute of Theoretical Physics of UNESP and supported by the São Paulo Research Foundation, FAPESP. Still a PhD student two years ago, Menezes was awarded competitive funding from the Brazilian federal agency CAPES to continue his doctoral research, supervised by Martinez-Garcia, in Görlitz. Menezes successfully defended his doctoral thesis at University of São Paulo’s Institute of Biosciences in early 2025.

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Journal

Ecology Letters

DOI

10.1111/ele.70269 

Method of Research

Computational simulation/modeling

Subject of Research

Animals

Article Title

The Range-Resident Logistic Model: A New Framework to Formalise the Population-Dynamics Consequences of Range Residency

 

Large study shows scaling start-ups risk increasing gender gaps

Stockholm School of Economics

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image: 

Mohamed Genedy, Postdoctoral Fellow, Stockholm School of Economics 

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Credit: SSE

When startups scale quickly, founders often make hurried hiring decisions that unintentionally disadvantage women, according to new study from the Stockholm School of Economics in Sweden. The study shows how the pressures of rapid growth increase the likelihood that founders rely on mental shortcuts and make biased decisions. 

Drawing on large‑scale Swedish data, the study shows that scaling—when companies hire far more people than their usual growth trend would predict—puts pressure on founders to decide swiftly, which increases the use of mental shortcuts. These shortcuts can activate gender stereotypes, shaping who gets hired and who moves into managerial roles.  

“During those moments of rapid growth, even well‑intentioned leaders can fall back on familiar stereotypes when assessing who they believe is best suited for the role,” says Mohamed Genedy, co-author and Postdoctoral Fellow at the House of Innovation, Stockholm School of Economics. 

Reduced odds of hiring female managers 

His research analyzes more than 31,000 new ventures founded in Sweden between 2004 and 2018. It finds that in male‑led startups, scaling reduces the odds of hiring a woman by about 18 percent, and the odds of appointing a woman to a managerial position by 22 percent.  

These patterns emerge even in a highly gender‑equal national context, making the findings especially noteworthy.  

Crucially, the study reveals that founders with HR‑related education counteract these challenges. In ventures led by founders with HR training, the odds of hiring a woman increase by more than 30 percent, and the odds of appointing a woman to a managerial role increase by 14 percent for the same level of scaling.  

“When founders have experience with structured hiring practices, the gender gaps shrink, and in some cases even reverse,” Genedy says.  

“This shows that getting the basics of HR right early on really pays off. When things start moving fast, founders with HR knowledge are less likely to rely on biased instincts and more likely to hire from a broader talent pool.”  

Prior experience in companies with established HR practices also helps, though less so. It raises the likelihood of hiring women as the new ventures scale, but does not significantly affect managerial appointments. 

Differences persist in female-led ventures 

The study additionally shows that these patterns are not driven by founder gender alone. Even solo female‑led ventures display similar tendencies when scaling, though to a somewhat lesser degree.  

And in female‑dominated industries, scaling increases the hiring of women for regular roles but still reduces the likelihood that women are appointed into managerial positions.  

“When scaling accelerates, cognitive bias kicks in for everyone,” says Mohamed Genedy. “Female founders are not immune to these patterns.”  

Together, these results point to underlying cognitive mechanisms that shape decisions under time pressure. 

The study was funded with support from Jan Wallanders and Tom Hedelius Stiftelse, Tore Browaldhs Stiftelse and the Kamprad Family Foundation for Entrepreneurship, Research and Charity. 

Publication  
Genedy, M. (2026). Scaling with Bias? The role of founders’ HR knowledge and experience in hiring and managerial appointments.  Human Resource Management 
 
About the Stockholm School of Economics  
The Stockholm School of Economics is rated as a top business school in the Nordic and Baltic countries and enjoys a strong international reputation. World-class research forms the foundation of our educational offering, which includes bachelor, master, PhD, MBA, and Executive Education programs. Our programs are developed in close cooperation with the business and research communities, providing graduates substantial potential to attain leading positions in companies and other organizations. 

The School is accredited by EQUIS, certifying that all of its principal activities – teaching as well as research – maintain the highest international standards. The Stockholm School of Economics is also the only Swedish member institution of CEMS and PIM, which are collaborations between top business schools worldwide, contributing to the level of quality for which our school is known. 

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Journal

Human Resource Management

DOI

10.1002/hrm.70056 

Method of Research

Observational study

Subject of Research

People

Article Title

Scaling with Bias? The role of founders’ HR knowledge and experience in hiring and managerial appointments

Article Publication Date

1-Feb-2026

Navigating academic integrity in biomedical research: The impact of large language models on current practices and future directions

FAR Publishing Limited

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Large language models are predominantly applied in four major academic domains: (1) Research Paper Writing Assistance: LLMs facilitate manuscript preparation through translation services, comprehensive proofreading, and multiple perspective analysis, while simultaneously managing auxiliary tasks such as data organization, thereby substantially enhancing research productivity. (2) Research Data Analysis Support: LLMs exhibit emerging capabilities in dataset compilation, analytical processing, and automated code generation, leading to significant improvements in research efficiency. (3) Academic Visualization Generation: LLMs enhance the traditional visualization process through automated generation of scientific illustrations and data representations, facilitating more effective communication of research findings. (4) Academic Peer Review Support: LLMs contribute to both manuscript self-assessment and formal review processes by providing systematic content evaluation and generating structured review feedback.This figure was created based on the tools provided by Biorender.com (accessed on 20/08/2025)

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Credit: Anqi Lin, Zuwei Chen, Aimin Jiang, Bufu Tang, Chang Qi, Lingxuan Zhu, Weiming Mou, Wenyi Gan, Dongqiang Zeng, Mingjia Xiao, Guangdi Chu, Shengkun Peng, Hank Z.H. Wong, Lin Zhang, Hengguo Zhang, Xinpei Deng, Quan Cheng, Jian Zhang, Peng Luo

As Large Language Models (LLMs) continue to advance, they have garnered widespread public attention and extensive application across numerous industries and academic disciplines. The proliferation of LLMs has sparked considerable research interest, with studies primarily focusing on their technical characteristics and specific application scenarios. However, systematic research examining the impact of LLMs on academic integrity remains relatively scarce. Academic integrity is of paramount importance in the biomedical field. Therefore, this paper aims to examine both the opportunities and challenges that LLMs present to academic integrity in the biomedical field, and proposes solutions for optimizing the beneficial applications of LLMs. From a positive perspective, LLMs offer substantial benefits to researchers by enhancing research efficiency, improving research quality, and facilitating the generation and dissemination of academic insights. However, they also present numerous challenges, including the potential for promoting academic misconduct, generating content inaccuracies or ambiguous expressions, introducing bias and fairness concerns, compromising peer review mechanisms, facilitating the dissemination of misinformation, and undermining higher education—all of which demand careful attention. To address these issues, we propose solutions and feasible strategies centered on ten core dimensions: establishing policies and regulatory guidelines, enhancing AI literacy and application capabilities, developing and improving relevant technical tools, establishing human-AI collaboration models, reforming peer review procedures and academic evaluation systems, promoting international cooperation and standardization, increasing transparency and strengthening disclosure, reinforcing professional ethics education, and advancing artificial intelligence detection technologies. Overall, while LLMs undoubtedly pose challenges for maintaining academic integrity, their potential for positive impact remains promising. It is anticipated that with technological advancement and improved ethical standards, LLMs will ultimately preserve and strengthen academic integrity.

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Journal

International Journal of Surgery

DOI

10.1097/JS9.0000000000003839 

Method of Research

Literature review

Article Title

Navigating Academic Integrity in Biomedical Research: The Impact of Large Language Models on Current Practices and Future Directions

FREYA'S DAY SCIENCE DUMP

THE CREATOR, IF HE EXISTS, IS INORDINATELY FOND OF BEETLES
AND STARS

J.B.S HALDANE 

 

Scientists uncover the molecular marvel behind spider silk’s super powers

King's College London

Scientists have identified the molecular interactions that give spider silk its exceptional strength and flexibility, opening the door to new bio-inspired materials for aircraft, protective clothing and medical applications, and even advancing our understanding of neurological conditions such as Alzheimer’s disease.

The findings, published in the journal Proceedings of the National Academy of Sciences  by researchers at King’s College London and San Diego State University (SDSU), establish general design principles that could guide the development of a new class of high-performance, sustainable fibres.

The joint research is the first to show how the amino acids that make up spider silk proteins interact to behave like molecular “stickers”.    

Chris Lorenz, Professor of Computational Materials Science at King’s College London, who led the UK side of the research, said: “The potential applications are vast - lightweight protective clothing, airplane components, biodegradable medical implants, and even soft robotics could benefit from fibres engineered using these natural principles.”

Spider dragline silk is stronger than steel by weight and tougher than Kevlar - the material used to fabricate bullet-proof vests. The exceptional natural material forms the framework of a spider’s web and is also used for suspension, and researchers have long sought to understand how to recreate its unique properties.

Dragline silk is produced in a spider’s silk gland, where proteins are stored as a concentrated liquid known as “silk dope” before being spun into solid fibres.

While it has been known that these proteins first condense into liquid-like droplets before being extruded into fibres, the molecular mechanism linking this process to the silk’s final structure has remained unclear.

The interdisciplinary team of chemists, biophysicists and engineers used a combination of advanced computational and experimental tools - including molecular dynamics simulations, AlphaFold3 structural modelling and nuclear magnetic resonance spectroscopy - to demonstrate that the amino acids arginine and tyrosine interact to trigger the initial clustering of the proteins.

Crucially, these same interactions persist as the silk fibre forms, helping to create the complex nanostructure responsible for its exceptional mechanical performance.

“This study provides an atomistic-level explanation of how disordered proteins assemble into highly ordered, high-performance structures,” added Lorenz.

Gregory Holland, SDSU professor of physical and analytical chemistry, who led the US side of the research, said one of the most surprising outcomes was how chemically sophisticated the process turned out to be.

“What surprised us was that silk - something we usually think of as a beautifully simple natural fibre - actually relies on a very sophisticated molecular trick,” Holland said. “The same kinds of interactions we discovered are used in neurotransmitter receptors and hormone signalling.”

He suggested the findings could therefore extend into human health research.

“The way silk proteins undergo phase separation and then form β-sheet–rich structures      mirrors mechanisms we see in neurodegenerative diseases such as Alzheimer’s,” Holland said. “Studying silk gives us a clean, evolutionarily-optimized system to understand how phase separation and β-sheet formation can be controlled.”

 

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Journal

Proceedings of the National Academy of Sciences