Fri, 13 Nov 2026

11:00 - 12:00
L4

Remodelling selection to debias population research

Prof Gabriela Gomes
(Dept of Mathematics and Statistics University of Strathclyde)
Abstract

Every population consists of individuals who vary in their traits, and each trait may, or may not, be associated with frailty or fitness. Variation in frailty and fitness traits makes population studies prone to selective depletion bias (SDB). The issue is widespread across scientific domains. When an ageing cohort exhibits declining mortality, is it individuals becoming healthier or selective depletion of the frail? In an epidemic, when growth in cumulative infections decelerates, is it individuals cautiously changing behaviour or selective depletion of the most susceptible? In microbial populations, when mutations increase population vulnerability to stress, it is individuals becoming more vulnerable or mutant populations having higher variance in fitness? In each case, the first explanation invokes individuals changing, while the second recognises that populations change due to selection on pre-existing variation. While the former are intuitive and widely adopted, explanations that rely on selective depletion are more neutral and less commonly considered due to cognitive biases and challenges in estimating all variation that matters. 

Remodelling selection (ReMS) is proposed as a general strategy of study design and analysis to address the SDB problem. I will show how the approach has been employed in specific case studies and how it has been formalised in general.

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Fri, 30 Oct 2026

11:00 - 12:00
L4

Growth accelerations are the key to the niche

Dr Oliver Meacock
(School of Biosciences University of Sheffield)
Abstract
The relationship between organisms and their environment is the heart of ecology. Microbes exemplify this relationship, modifying their shared chemical environment to engage in cooperative exchanges, kill each other with deadly toxins and compete over limited resources. Understanding the environment-organism coupling - the topic of niche theory - is therefore key to manipulating microbiota. 
Much of our understanding of the niche comes from rate-based frameworks. For example, resource competition is typically described using the logistic equation, which states that growth rates tend to zero as population densities increase toward their carrying capacity. The mechanisms driving these population dynamics are implicit, with the underlying resource dynamics abstracted out of the model.
Starting from mechanistically-explicit consumer-resource models, I will argue that growth accelerations (resulting from the combination of the timescales of both environmental and population dynamics) provide a more powerful understanding of the niche than rate-based perspectives. Exploiting an exact homology between the equations describing consumer-resource systems and the generalised Lotka-Volterra (gLV) model, I will demonstrate that basic concepts such as density-dependence and context-dependencies of interactions can be accurately captured with an accelerational lens. Moreover, derived frameworks such as Modern Coexistence Theory (MCT) can be readily translated into an accelerational form, enabling their integration into mechanistic frameworks. Finally, I will exploit this homology to explain how obligatory mutualistic exchanges between bacteria can be reconciled with ecosystem stability, contrasting with predictions from the gLV model.


 

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Fri, 23 Oct 2026

11:00 - 12:00
L4

Microscopic theories of reaction-diffusion processes and applications to biological systems

Dr Rosalba Garcia-Millan
(Dept of Mathematics, Kings College London)
Abstract

Reaction-diffusion processes underpin countless biological phenomena. In these systems, fluctuations play an important role, particularly when the number of interacting units is small. In chemical reactions, for example, mean-field approaches such as the law of mass action neglect fluctuations and thus fail to capture absorbing states. In this talk, I will introduce Doi-Peliti field theory (DPFT), a microscopic framework that uses ladder operators to represent particle dynamics in second-quantized form. Its path-integral formulation is exact at the level of the action and allows observables to be calculated systematically in a perturbative expansion.

I will show how DPFT can be used to model biological systems, including oscillating neuronal avalanches [1] and disease spreading on general graphs [2]. I will also present recent progress in microscopic theories of active matter, describing the emergence of effective attraction between interacting run-and-tumble particles [3,4] and the role of delay in reconfigurable chiral microswimmers [5].


[1] J. Pausch, R. Garcia-Millan, and G. Pruessner, Time-dependent branching processes: a model of oscillating neuronal avalanches, Sci. Rep. 10, 13678 (2020). 
[2] I. Bordeu, S. Amarteifio, R. Garcia-Millan, B. Walter, N. Wei, and G. Pruessner, Volume explored by a branching random walk on general graphs. Sci. Rep. 9, 15590 (2019).
[3] R. Garcia-Millan, L. Cocconi, Z. Zhang, M. Bothe, L. Chen, Z. Zhen, G. Pruessner, Effective attraction by repulsion, arXiv:2605.01421 (2026). 
[4] R. Garcia-Millan, Z. Zhang, L. Cocconi, M. Bothe, L. Chen, Z. Zhen, G. Pruessner, Microscopic theory of soft run- and-tumble particles, arXiv:2605.01422 (2026).
[5] J. Peltier, C. Britton, L. Alvarez, R. Garcia-Millan, in preparation (2026).

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Have your say on how your teaching, research, labs and office spaces could be improved. The University is working with architects to rethink how Oxford's spaces and buildings are designed. Share your views on which spaces work well and which ones could be improved. Your feedback will inform future design choices, as the University works towards flexible, inclusive and consistent spaces.

Spatial continuity of neurons explains non-random network architecture
 Reimann, M Egas Santander, D Kanari, L Barros-Zulaica, N iScience volume 29 issue 6 116144-116144 (01 Jun 2026) doi:10.1016/j.isci.2026.116144

Award for Milena Vuletic

Our recent CDT alumna Milena Vuletic has been awarded  the 6th PLEXUS Award for AI in the Financial Sector for her DPhil thesis on Multi-asset financial markets: mathematical modelling and data-driven approaches.

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Fri, 16 Oct 2026

11:00 - 12:00
L4

Emergent phenomena in protein complexes out of equilibrium: from topologically-protected states to computation

Dr Jaime Agudo-Canalejo
(Dept of Physics & Astronomy UCL)
Abstract
Protein complexes, typically made up of a small number of identical subunits, are very common in biology. These subunits can additionally undergo post-translational modifications, such as phosphorylation and dephosphorylation, resulting in a high dimensional state space for the protein complex. Importantly, such modifications are catalyzed by enzymes that are driven out of equilibrium by the consumption of a fuel such as ATP. I will discuss, from a theoretical perspective, how very simple enzyme-catalyzed operations at the single subunit level can result in emergent behaviour at the level of the entire protein complex. First, I will discuss how topologically-protected edge currents emerge and become enhanced in arbitrarily high-dimensional stochastic systems representing the state of the complex, extending previous results for two-dimensional stochastic systems [1]. Second, I will discuss how enzymes that act on a subunit in a context-dependent manner provide a molecular implementation of stochastic cellular automata,  that can be exploited to engineer molecular-scale computing devices, such as an error-tolerant memory or a finite-state machine [2].
 
[1] E. Tang, J. Agudo-Canalejo, and R. Golestanian, Phys. Rev. X 11, 031015 (2021)
[2] J. Kocka, K. Husain, and J. Agudo-Canalejo, PRX Life 4, 013036 (2026)
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