  We investigated the impact of uncertainties in neutron-capture and weak
reactions (on heavy elements) on the s-process nucleosynthesis in low-mass
stars and massive stars using a Monte-Carlo based approach. We performed
extensive nuclear reaction network calculations that include newly evaluated
temperature-dependent upper and lower limits for the individual reaction rates.
We found beta-decay rate uncertainties affect only a few nuclei near s-process
branchings, whereas most of the uncertainty in the final abundances is caused
by uncertainties in the neutron capture rates. We suggest a list of uncertain
rates as candidates for improved measurement by future experiments.
