  We present evolutionary models for solar-like stars with an improved
treatment of convection that results in a more accurate estimate of the radius
and effective temperature. This is achieved by improving the calibration of the
mixing-length parameter, which sets the length scale in the 1D convection model
implemented in the stellar evolution code. Our calibration relies on the
results of 2D and 3D radiation hydrodynamics simulations of convection to
specify the value of the adiabatic specific entropy at the bottom of the
convective envelope in stars as a function of their effective temperature,
surface gravity and metallicity. For the first time, this calibration is fully
integrated within the flow of a stellar evolution code, with the mixing-length
parameter being continuously updated at run-time. This approach replaces the
more common, but questionable, procedure of calibrating the length scale
parameter on the Sun, and then applying the solar-calibrated value in modeling
other stars, regardless of their mass, composition and evolutionary status. The
internal consistency of our current implementation makes it suitable for
application to evolved stars, in particular to red giants. We show that the
entropy calibrated models yield a revised position of the red giant branch that
is in better agreement with observational constraints than that of standard
models.
