  We examine localized kinetic terms for gauge fields which can propagate into
compact extra dimensions. We find that such terms are generated by radiative
corrections in both theories with matter fields confined to branes and in
theories imposing orbifold boundary conditions on bulk matter. In both cases,
the radiative corrections are logarithmically divergent, indicating that from
an effective field theory point of view they cannot be predicted in terms of
other parameters, and should be treated as independent leading order parameters
of the theory. Specializing to the five dimensional case, we show that these
terms may result in gross distortions of the Kaluza-Klein gauge field masses,
wave functions, and couplings to brane and bulk matter. The resulting
phenomenological implications are discussed.
