  Shell-model calculations that include both Lambda and Sigma configurations
with p-shell cores are used to interpret gamma-ray transitions in Lambda-7Li,
-9Be, -10B, -11B, -12C, -15N, and -16O observed with the Hyperball array of Ge
detectors. It is shown that the data puts strong constraints on the spin
dependence of the Lambda-N effective interaction and that the Lambda-Sigma
coupling plays an important role.
