  We investigate the chiral and the deconfinement transition within the
framework of Dyson-Schwinger equations using quenched lattice data for the
temperature dependent gluon propagator as input. We extract corresponding order
parameters from the Landau gauge quark propagator with U(1)-valued boundary
conditions. We study the chiral transition using the conventional quark
condensate, whereas for the deconfinement transition we determine the dual
condensate ('dressed Polyakov loop'). In addition we consider an alternative
order parameter for deconfinement, the dual scalar quark dressing function. As
a result we find almost the same transition temperatures for the chiral and
deconfinement transitions.
