Measurements of $BR(b \to \tau^{-}\overline{\nu}_{\tau}X)$ and $BR(b \to \tau^{-}\overline{\nu}_{\tau}D^{*\pm}X)$ and upper limits on $BR(B^{-} \to \tau^{-}\overline{\nu}_{\tau})$ and $BR(b \to s\nu\overline{\nu})$

Using the LEP I ALEPH data the branching ratio BR(b->tau nu X) is measured. The branching ratio BR(b->tau nu D*+-(X)) is also measured and 90§onfidence level limits are established for BR(B- ->tau nu) and BR(b ->s nu nu). These measurements allow to set a 90xonfidence level constraint on tan(beta)/M_H for the charged Higgs mass in the frame of any type II Higgs doublet model.