  Nucleosynthesis beyond Fe poses additional challenges not encountered when
studying astrophysical processes involving light nuclei. Generally higher
temperatures and nuclear level densities lead to stronger contributions of
transitions on excited target states. This may prevent cross section
measurements to determine stellar reaction rates and theory contributions
remain important. Furthermore, measurements often are not feasible in the
astrophysically relevant energy range. Sensitivity analysis allows not only to
determine the contributing nuclear properties but also is a handy tool for
experimentalists to interpret the impact of their data on predicted cross
sections and rates. It can also speed up future input variation studies of
nucleosynthesis by simplifying an intermediate step in the full calculation
sequence. Large-scale predictions of sensitivities and ground-state
contributions to the stellar rates are presented, allowing an estimate of how
well rates can be directly constrained by experiment. The reactions
185W(n,gamma) and 186W(gamma,n) are discussed as application examples. Studies
of uncertainties in abundances predicted in nucleosynthesis simulations rely on
the knowledge of reaction rate errors. An improved treatment of uncertainty
analysis is presented as well as a recipe for combining experimental data and
theory to arrive at a new reaction rate and its uncertainty. As an example, it
is applied to neutron capture rates for the s-process, leading to larger
uncertainties than previously assumed.
