  We present a general approach to incorporate hadronic as well as quark
degrees of freedom in a unified approach. This approach implements the correct
degrees of freedom at high as well as low temperatures and densities. An
effective Polyakov loop field serves as the order parameter for deconfinement.
We employ a well-tested hadronic flavor-SU(3) model based on a chirally
symmetric formulation that reproduces properties of ground state nuclear matter
and yields good descriptions of nuclei and hypernuclei. Excluded volume effects
simulating the finite size of the hadrons drive the transition to quarks at
high temperatures and densities. We study the phase structure of the model and
the transition to the quark gluon plasma and compare results to lattice gauge
calculations.
