  In theories with extra dimensions there are generically brane kinetic terms
for fields living in the bulk. These modify the masses and wave functions of
the Kaluza-Klein expansions, and then the effective four dimensional gauge and
Yukawa couplings of the corresponding modes. Here, we discuss some
phenomenological consequences of fermion brane kinetic terms, emphasizing their
implications for models with low compactification scales, whose agreement with
experiment can be improved, and observable effects at collider energies, like
the production of new fermions.
