  Some aspects of a0-f0 mixing effects in the reaction ${\vec p} n\to da^0_0$
with perpendicular polarized proton beam are discussed. An angular--asymmetry
parameter $A$ is defined to study those effects. It is shown that, for energies
close to the production threshold, the angular--asymmetry parameter $A(\theta,
\phi)$ is proportional to the a0-f0 mixing amplitude for arbitrary polar and
azimuthal angles $\theta$ and $\phi$ of the outgoing $a_0$ meson. This
statement is also valid for arbitrary energies, but then only at polar angles
$\theta=0^0$ and $\theta=90^0$. The mass dependence of the differential cross
section $d\sigma/dm_{\pi^0\eta}$ in the reaction $pn\to d\pi^0\eta$ in the
presence of \mix mixing is also discussed.
