2011/03/28 by Jorge Ramírez, Ramirez, Jorge M · 1 citation
Mathematics · Medicine · #34K08 #35R02 #92D25 #FOS: Biological sciences #Mathematical Biology Tumor Growth #Mathematical and Theoretical Epidemiology and Ecology Models #Populations and Evolution (q-bio.PE) #advanced mathematical theories
paper · pdf · doi:10.48550/arxiv.1103.5488
openalex publication_date 2011/03/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
An integro-differential equation on a tree graph is used to model the evolution and spatial distribution of a population of organisms in a river network. Individual organisms become mobile at a constant rate, and disperse according to an advection-diffusion process with coefficients that are constant on the edges of the graph. Appropriate boundary conditions are imposed at the outlet and upstream nodes of the river network. The local rates of population growth/decay and that by which the organisms become mobile, are assumed constant in time and space. Imminent extinction of the population is understood as the situation whereby the zero solution to the integro-differential equation is stable. Lower and upper bounds for the eigenvalues of the dispersion operator, and related Sturm-Liouville problems are found, and therefore sufficient conditions for imminent extinction are given in terms of the physical variables of the problem.