  We present direct measurements of the parity-violation parameters $A_b$,
$A_c$, and $A_s$ at the $Z^0$ resonance with the SLD detector. The measurements
are based on approximately 530k hadronic $Z^0$ events collected in 1993-98.
Obtained results are $A_b = 0.914\pm0.024$ (SLD combined: preliminary), $A_c =
0.635\pm0.027$ (SLD combined: preliminary), and $A_s = 0.895\pm0.066(stat.)\pm
0.062(sys.)$.
