  In this short note we use a simple model to describe the dynamical effects of
break-up processes in the subbarrier fusion involving weakly bound nuclei. We
model two similar cases involving either a neutron or a proton halo nucleus,
both schematically coupled to the break-up channels. We find that the decrease
of the coulomb barrier in the proton break-up channel leads, ceteris paribus,
to a larger enhancement of the subbarier fusion probabilities with respect to
the neutron-halo case.
