Evolution of the temperature (top) and density (bottom) at the loop apex from hydrodynamic simulations using the two different radiative-loss functions: Rosner et al. (1978) (thin solid line) and version 7 of CHIANTI (thick solid line). Results obtained with analytical approximations (Cargill 1994) are also shown (dotted lines, see text for details). The level of 2 MK is marked (dash-dotted horizontal line).