Space Structures and Different Scales for Many-Component Biosystems

#### L. Triolo

2005, v.11, Issue 2, 389-404

ABSTRACT

The right scale of description, and more generally, the matching between different scales, in modelling physical or biological systems, presents a substantial interest and related difficulties. This applies for instance to competition/diffusion models of different species, or to the invasion process by an aggressive population against a native one, like tumor cells in a normal tissue. Under a suitable scaling the system may be described by PDE's where space structures are visible, as is shown and discussed here in a tumor growth model. On the other side, the separation of scales may be not so sharp: events occurring in microscopic" regions may affect the macroevolution considerably. This is shown here in a model of metastatic spreading which can be studied like a collection of proliferating" random walks on the positive one-dimensional lattice.

Keywords: scaling limits,stochastic modelling,tumor growth model