  The conductance for a single impurity in a one dimensional gas with
electron-electron interaction and Zeeman splitting $v_F^\uparrow -
v_F^\downarrow = \Delta \neq 0$ is considered. We find that for an extented
Hubbard model, $\rho_\uparrow^R \rho_\uparrow^L + \rho_\downarrow^R
\rho_\downarrow^L$, a Luttinger liquid for spin up and spin down is obtained.
As a result the conductances for spin up $G_\uparrow$ and spin down
$G_\downarrow$ are not equal. The anisotropy in the conductances $G_\uparrow
\neq G_\downarrow$ gives rise to a spin polarized wire.
