arXiv subjects

Gwenaël Peltier

Publications and source records attributed to Gwenaël Peltier.

4 recordsLinked to original sources

arXiv2025

Optimal strategies for Wolbachia mosquito replacement technique: influence of the carrying capacity on spatial releases

This work is devoted to the mathematical study of an optimization problem regarding control strategies of mosquito population in a heterogeneous environment. Mosquitoes are well-known vectors of diseases. For some diseases, such as dengue, it has been found that mosquitoes have a reduced vector capacity when carrying the endosymbiotic bacterium Wolbachia. We consider a mathematical model of a replacement technique consisting in rearing and releasing Wolbachia-infected mosquitoes to replace the wild population. Our goal is to optimize the release protocol to maximize replacement effectiveness in a spatially inhomogeneous environment. Using a scalar model with space-dependent carrying capacity, we explore the existence and properties of an optimal release profile maximizing the replacement across the domain. In particular, neglecting mosquito mobility and under some assumptions on the biological parameters, we characterize the optimal releasing strategy for a short time horizon, and we reduce the case of a long time horizon to a one-dimensional optimization problem. Our theoretical results are illustrated with several numerical simulations.

math.OC↗

arXiv2021

On the modelling of spatially heterogeneous nonlocal diffusion: deciding factors and preferential position of individuals

We develop general heterogeneous nonlocal diffusion models and investigate their connection to local diffusion models by taking a singular limit of focusing kernels. We reveal the link between the two groups of diffusion equations which include both spatial heterogeneity and anisotropy. In particular, we introduce the notion of deciding factors which single out a nonlocal diffusion model and typically consist of the total jump rate and the average jump length. In this framework, we also discuss the dependence of the profile of the steady state solutions on these deciding factors, thus shedding light on the preferential position of individuals.

math.AP↗

arXiv2021

Populations facing a nonlinear environmental gradient: steady states and pulsating fronts

We consider a population structured by a spacevariable and a phenotypical trait, submitted to dispersion,mutations, growth and nonlocal competition. This population is facing an {\it environmental gradient}: to survive at location $x$, an individual must have a trait close to some optimal trait $y_{opt}(x)$. Our main focus is to understand the effect of a {\it nonlinear} environmental gradient. We thus consider a nonlocal parabolic equation for the distribution of the population, with $y_{opt}(x) = \varepsilonθ(x)$, $0<\vert \varepsilon \vert \ll 1$. We construct steady states solutions and, when $θ$ is periodic, pulsating fronts. This requires the combination of rigorous perturbation techniques based on a careful application of the implicit function theorem in rather intricate function spaces. To deal with the phenotypic trait variable $y$ we take advantage of a Hilbert basis of $L^{2}(\mathbb{R})$ made of eigenfunctions of an underlying Schrödinger operator, whereas to deal with the space variable $x$ we use the Fourier series expansions. Our mathematical analysis reveals, in particular, how both the steady states solutions and the fronts (speed and profile) are distorted by the nonlinear environmental gradient, which are important biological insights.

math.AP↗

arXiv2019

Accelerating invasions along an environmental gradient

We consider a population structured by a space variable and a phenotypical trait, submitted to dispersion, mutations, growth and nonlocal competition. This population is facing an environmental gradient: the optimal trait for survival depends linearly on the spatial variable. The survival or extinction depends on the sign of an underlying principal eigenvalue. We investigate the survival case when the initial data satisfies a so-called heavy tail condition in the space-trait plane. Under these assumptions, we show that the solution propagates in the favorable direction of survival by accelerating. We derive some precise estimates on the location of the level sets corresponding to the total population in the space variable, regardless of their traits. Our analysis also reveals that the orientation of the initial heavy tail is of crucial importance.

math.AP↗