  We evaluate the in-medium spectral functions for pions, nucleon and isobar
resonances in a self consistent and covariant manner. The calculations are
based on a recently developed formulation which leads to predictions in terms
of the pion-nucleon scattering phase shifts and a set of Migdal parameters
describing important short range correlation effects. We do not observe
significant softening of pion modes if we insist on reasonable isobar resonance
properties but predict a considerable broadening of the N(1440) and N(1520)
resonances in nuclear matter. Contrasted results are obtained for the s-wave
N(1535) and N(1650) resonances which are affected by a nuclear environment very
little. The properties of slowly moving isobar's in nuclear matter are found to
depend very sensitively on a soft form factor in the piNN vertex, which is not
controlled by the piN scattering data.
