  Motivated by the recent determination of the top quark mass by the CDF
collaboration, $\mt =174 \pm 10 ^{+13}_{-12}$ GeV, we review and update
constraints on the parameters of the quark flavour mixing matrix $V_{CKM}$ in
the standard model. In performing these fits, we use inputs from the
measurements of $\abseps$, the CP-violating parameter in $K$ decays, $\xd =
(\delm)/\Gamma$, the mixing parameter in \bdbdbar\ mixing, the present
measurements of the matrix elements $\absvcb$ and $\absvub$, and the $B$-hadron
lifetimes. The CDF value for $\mt$ considerably reduces the CKM-parameter space
previously allowed. An interesting result of our analysis is that the present
data can be used to restrict the coupling constant product ratio
$f_{B_d}\sqrt{B_{B_d}}$ to the range 110-270 MeV -- in comfortable agreement
with existing theoretical estimates of this quantity. We use the updated CKM
matrix to predict the \bsbsbar\ mixing ratio $\xs$, as well as the quantities
$\sin 2\alpha$, $\sin 2\beta$ and $\sin^2\gamma$, which characterize
  CP-violating asymmetries in $B$-decays.
