We study the global existence and space-time asymptotics of solutions for a
class of nonlocal parabolic semilinear equations. Our models include the
Nernst-Planck and the Debye-Hukel drift-diffusion systems as well as
parabolic-elliptic systems of chemotaxis. In the case of a model of
self-gravitating particles, we also give a result on the finite time blow up of
solutions with localized and oscillating complex-valued initial data, using a
method by S. Montgomery-Smith.Comment: Colloq. Math. (to appear