  We consider the presence and evolution of primordial density perturbations in
a cosmological model based on a simple ansatz which captures -- by providing a
set of effective gravitational field equations -- the strength of the enhanced
quantum loop effects that can arise during inflation. After deriving the
general equations that perturbations obey, we concentrate on scalar
perturbations and show that their evolution is quite different than that of
conventional inflationary models but still phenomenologically acceptable. The
main reason for this novel evolution is the presence of an oscillating regime
after the end of inflation which makes all super-horizon scalar modes
oscillate. The same reason allows for a natural and very fast reheating
mechanism for the universe.
