O(ALPHA-ALPHA(S)LN-M(T)(2)) NONUNIVERSAL CORRECTIONS TO THE DECAY-RATE GAMMA(Z-](B)OVER-BAR)

The partial decay rate Gamma (Z --> b ($) over bar b) is significantly influenced by the mass of the top quark due to electroweak radiative corrections. The leading similar to m(1)(2) and the next-to-leading co ntribution similar to In m(t)(2) are known to be numerically of simila r size, In this work we calculate the QCD corrections to the logarithm ic correction using the heavy top mass expansion. The O (alpha alpha(s ) In m(t)(2)) corrections are of the same order as the QCD corrections to the quadratic top mass term, but of different sign.