Polarization phenomena in the reaction $NN \to NN\pi$ near threshold

First calculations for spin-dependent observables of the reactions $pp \topp\pi^0$, $pp \to pn\pi^+$ and $pp \to d\pi^+$ near threshold are presented,employing the J\"ulich model for pion production. The influence of resonant(via the excitation of the $\Delta (1232)$) and non-resonant p-wave pionproduction mechanisms on these observables is examined. For the reactions $pp\to pn\pi^+$ and $pp \to d\pi^+$ nice agreement of our predictions with thepresently available data on spin correlation coefficents is observed whereasfor $pp \to pp\pi^0$ the description of the data is less satisfying