  We show that for the active-sterile flavor mixing parameters suggested by the
reactor neutrino anomaly, substantial \\nu_e-\\nu_s and \bar \\nu_e-\bar \\nu_s
conversion occurs in regions with electron fraction of \approx 1/3 near the
core of an 8.8 M_sun electron-capture supernova. Compared to the case without
such conversion, the neutron-richness of the ejected material is enhanced to
allow production of elements from Sr, Y, and Zr up to Cd in broad agreement
with observations of the metal-poor star HD 122563. Active-sterile flavor
conversion also strongly suppresses neutrino heating at times when it is
important for the revival of the shock. Our results suggest that simulations of
supernova explosion and nucleosynthesis may be used to constrain active-sterile
mixing parameters in combination with neutrino experiments and cosmological
considerations.
