  We perform classical non-equilibrium molecular dynamics simulations to
calculate heat flow through a microscopic junction connecting two larger
reservoirs. In contrast to earlier works, we also include the reservoirs in the
simulated region to study the effect of the bulk-nanostructure interfaces and
the bulk conductance. The scalar Fermi--Pasta--Ulam (FPU) model is used to
describe the effects of anharmonic interactions in a simple manner. The
temperature profile close to the junction in the low temperature limit is shown
to exhibit strong directional features that fade out when temperature
increases. Simulating both the FPU chain and the two bulk regions is also shown
to eliminate the non-monotous temperature variations found for simpler
geometries and models. We show that with sufficiently large reservoirs, the
temperature profile in the chain does not depend on the details of
thermalization used at the boundaries.
