Laplace transform QCD sum rules for two-point functions related to the stra
ngeness-changing scalar and pseudoscalar Green's functions psi (Q(2)) and p
si (5)(Q(2)), are used to determine the subtraction constants psi (0) and p
si (5)(0), which fix the ratio R-su equivalent to ((s) over bars) / ((u) ov
er baru). Our results are psi (0) = -(1.06 +/- 0.21) x 10(-3) GeV4, psi (5)
(0) = (3.35 +/- 0.25) x 10(-3) GeV4, and R-su equivalent to ((s) over bars)
/ ((u) over baru) = 0.5 +/- 0.1. This implies corrections to kaon-PCAC at
the level of 50%, which although large, are not inconsistent with the size
of the corrections to Goldberger-Treiman relations in SU(3) circle times SU
(3). (C) 2001 Published by Elsevier Science B.V.