MS03 - MEPI-08 Part 1 of 3

Modeling Complex Adaptive Systems in Life and Social Sciences (Part 1)

Tuesday, July 15 at 10:20am

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Note: this minisymposia has multiple sessions. The other sessions are: Part-2 and Part-3.

Yun Kang (Arizona State University), Tao Feng, Yangzhou University & University of Alberta

Description:

Utilizing complex adaptive systems in modeling has proven to be a powerful approach for understanding various aspects of life and social sciences across spatial and temporal scales. This special session will bring together a distinguished and diverse group of scholars from mathematics, biology, ecology, and epidemiology. These experts apply mathematical models and theoretical analysis to gain insights into critical biological, epidemiological, and social challenges. The session aims to provide an effective platform for presenting and discussing the latest research, fostering collaboration among professionals from different universities and career stages. Our goal is to encourage a rich exchange of ideas by assembling a group of researchers with diverse backgrounds, with a particular emphasis on promoting minority representation. The invited speakers span institutions across multiple countries and include individuals at various career stages, from early-career researchers to senior scholars. This inclusive approach ensures equal opportunities for all participants to present their findings and engage in meaningful collaborations.

Gail SK Wolkowicz

McMaster University

"Analysis of a New Discrete Two-Species Competition Model"

A new discrete model of competition between two-species is introduced and analyzed. Depending upon the parameter values, the model admits all of the outcomes of the classical Lotka-Volterra like competition model: one species wins the competition independent of the initial conditions; there is a unique coexistence equilibrium that is a saddle and the winning species depends on the initial conditions; or there is a unique coexistence equilibrium that is asymptotically stable and coexistence is independent of the initial conditions. However, as well, for parameters in this model, both species can die out or there can be multiple coexistence equilibria and more than one can be locally asymptotically stable. In the symmetric case, that is all corresponding parameters are equal, unlike the classical model in which are is a line of equilibria that are all stable but not asymptotically stable, In this model there are either none, one, or three coexistence equilibria and when there are three two of the coexistence equilibria are stable and both boundary equilibria are unstable.

Zhisheng Shuai

University of Central Florida

"A Tale of Two Incidence Functions in Epidemiological Models"

The choice of incidence function in epidemiological modeling profoundly influences the predicted disease dynamics, especially in contexts involving population size variation and behavioral responses. In this presentation, we examine a model that incorporates post-infection mortality and partial immunity, comparing the effects of mass-action and standard incidence functions. With the mass-action incidence, the model exhibits periodic solutions under certain parameter conditions. In contrast, applying the standard incidence reduces the likelihood of periodic solutions, potentially eliminating them entirely.

Qi Deng

York University

"Simulating the impact of a chlamydia vaccine in the US: An agent-based modeling approach"

Chlamydia trachomatis (CT) infection is the most reported bacterial sexually transmitted infection in the United States. Despite many cases being asymptomatic, infection can lead to complications such as pelvic inflammatory disease (PID) in females, and infertility in both females and males. We developed an agent-based transmission model to evaluate the impact of a potential CT vaccine on the prevalence of CT infections and associated PID in a population, side by side with existing screening and treatment programs. The model tracks sexually active agents aged 15-54 and simulates an evolving sexual network in a heterogeneous population consisting of heterosexuals, female sex workers and men who have sex with men. The effect of each agent’s full prior CT infection history on both CT susceptibility and, for female agents the risk of acquiring PID is modelled. The model uses a simple and flexible two-step approximate Bayesian computation (ABC) approach to calibrate both CT and PID prevalence to real-world data, allowing straightforward model adaptation to different population settings. Model “production runs” use ensembles of simulations to generate probabilistic distributions for all outputs. This model is designed to be used as a decision support tool for vaccine developers, policymakers and public health officials, able to generate actionable insights for both early-stage clinical development (to inform the selection of a vaccine performance target product profile, TPP), and for design and implementation of a CT vaccination program (to inform vaccination age, catch-up program, boosting, use of targeted versus universal vaccination, and uptake targets). It can also be used to investigate the value of re-allocating resources from screening to vaccination. We will present model results to illustrate various examples of the above use cases, using the US population as the setting. This work is supported by an NSERC grant co-funded by Sanofi.

Hermann J Eberl

University of Guelph

"Oscillations in a simple model of quorum sensing controlled EPS production in biofilms"

Bacterial biofilms are microbial depositions on inert surfaces. In the initial stages of biofilm formation bacteria attach to the surface, proliferate and start the production of extracellular polymeric substances that hold them together. EPS production is controlled by a quorum sensing mechanism. Biomass (cells and EPS) is detached into the aqueous environment by erosion or sloughing. Utilising the classical Wanner-Gujer 1D biofilm modeling concept one arrives at a model that consists of a system of ODEs for the reactor, a nonlocal hyperbolic system of balance laws for the biofilm proper, and a system of two point boundary value problems for dissolved susbtances such as nutrients and quorum sensing signal in the biofilm. We report and discuss numerical simulations that show the system can, depending on parameters, attain an upregulated steady state, a down-regulated steady state, and in the transition between these two passes through an oscillatory regime. This is joint work with Maryam Ghasemi and Firaz Khan.

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Annual Meeting for the Society for Mathematical Biology, 2025.