We report simultaneous measurement of shot noise and dc
transport in a quantum point contact as a function of
source-drain bias, gate voltage, and in-plane magnetic field.
Shot noise at zero field exhibits an asymmetry related to the
0.7 structure in conductance. The asymmetry in noise evolves
smoothly into the symmetric signature of spin-resolved
electron transmission at high field. Comparison to a
phenomenological model with density-dependent level splitting
yields good quantitative agreement.