  We consider cosmological implications of the formula for the dark energy
density derived by Gurzadyan and Xue which predicts a value fitting the
observational one. Cosmological models with varying by time physical constants,
namely, speed of light and gravitational constant and/or their combinations,
are considered. In one of the models, for example, vacuum energy density
induces effective negative curvature, while another one has an unusual
asymptotic. This analysis also explicitely rises the issue of the meaning and
content of physical units and constants in cosmological context.
