Nehari's problem and competing species systems
New dimensions in Gompertzian growth.
New results on global exponential stability of almost periodic solutions for a delayed Nicholson blowflies model
This paper is concerned with a class of Nicholson's blowflies models with multiple time-varying delays, which is defined on the nonnegative function space. Under appropriate conditions, we establish some criteria to ensure that all solutions of this model converge globally exponentially to a positive almost periodic solution. Moreover, we give an example with numerical simulations to illustrate our main results.
Non local reaction-diffusion equations modelling predator-prey coevolution.
In this paper we examine a predator-prey system with a characteristic of the predator subject to mutation. The ultimate equilibrium of the system is found by Maynard-Smith et al. by the so-called ESS (Evolutionary Stable Strategy). Using a system of reaction-diffusion equations with non local terms, we conclude that ESS result for the diffusion coefficient tending to zero, without resorting to any optimization criterion.
Nonautonomous ultraparabolic equations applied to population dynamics.
Non-constant positive steady states for a predator-prey cross-diffusion model with Beddington-DeAngelis functional response.
Nonlinear evolution equations with exponential nonlinearities: conditional symmetries and exact solutions
New Q-conditional symmetries for a class of reaction-diffusion-convection equations with exponential diffusivities are derived. It is shown that the known results for reaction-diffusion equations with exponential diffusivities follow as particular cases from those obtained here but not vice versa. The symmetries obtained are applied to construct exact solutions of the relevant nonlinear equations. An application of exact solutions to solving a boundary-value problem with constant Dirichlet conditions...
Nonlinear Leray-Schauder alternatives and application to nonlinear problem arising in the theory of growing cell population
Motivated by a mathematical model of an age structured proliferating cell population, we state some new variants of Leray-Schauder type fixed point theorems for (ws)-compact operators. Further, we apply our results to establish some new existence and locality principles for nonlinear boundary value problem arising in the theory of growing cell population in L 1-setting. Besides, a topological structure of the set of solutions is provided.
Nonlinear modelling and qualitative analysis of a real chemostat with pulse feeding.
Nonlinear stabilizing control of an uncertain bioprocess model
In this paper we consider a nonlinear model of a biological wastewater treatment process, based on two microbial populations and two substrates. The model, described by a four-dimensional dynamic system, is known to be practically verified and reliable. First we study the equilibrium points of the open-loop system, their stability and local bifurcations with respect to the control variable. Further we propose a feedback control law for asymptotic stabilization of the closed-loop system towards a...
Nonstandard numerical integrations of a Lotka-Volterra system.
Nonstandard numerical methods for a class of predator-prey models with predator interference.
Note on the persistent property of a discrete Lotka-Volterra competitive system with delays and feedback controls.
Null controllability and application to data assimilation problem for a linear model of population dynamics
In this paper we study a linear population dynamics model. In this model, the birth process is described by a nonlocal term and the initial distribution is unknown. The aim of this paper is to use a controllability result of the adjoint system for the computation of the density of individuals at some time .
Null controllability of a coupled model in population dynamics
We are concerned with the null controllability of a linear coupled population dynamics system or the so-called prey-predator model with Holling type I functional response of predator wherein both equations are structured in age and space. It is worth mentioning that in our case, the space variable is viewed as the “gene type” of population. The studied system is with two different dispersion coefficients which depend on the gene type variable and degenerate in the boundary. This system will be governed...
Null controllability of a nonlinear population dynamics problem.
Numerical optimization of parameters in systems of differential equations
We present results on the estimation of unknown parameters in systems of ordinary differential equations in order to fit the output of models to real data. The numerical method is based on the nonlinear least squares problem along with the solution of sensitivity equations corresponding to the differential equations. We will present the performance of the method on the problem of fitting the output of basic compartmental epidemic models to data from the Covid-19 epidemic. This allows us to draw...
Numerical solution of a new hydrodynamic model of flocking
This work is concerned with the numerical solution of a hydrodynamic model of the macroscopic behavior of flocks of birds due to Fornasier et al., 2011. The model consists of the compressible Euler equations with an added nonlocal, nonlinear right-hand side. As noticed by the authors of the model, explicit time schemes are practically useless even on very coarse grids in 1D due to the nonlocal nature of the equations. To this end, we apply a semi-implicit discontinuous Galerkin method to solve the...
Numerical solutions of a fractional predator-prey system.
Numerical study of a descending sphere in a low Reynolds number strongly stratified fluid.