  We study heat transport in the context of Hamiltonian and related stochastic
models with nearest-neighbor coupling, and derive a universal law for the
temperature profiles of a large class of such models. This law contains a
parameter $\alpha$, and is linear only when $\alpha=1$. The value of $\alpha$
depends on energy-exchange mechanisms, including the range of motion of tracer
particles and their times of flight.
