CMB acoustic scale in the entropic-like accelerating universe
  We consider generalizations of the entropic accelerating universe recently
proposed in Ref. [4,5] and show that their background equations can be made
equivalent to a model with a dark energy component with constant parameter of
state $w_{X} = -1 + 2\, \gamma /3$, where $\gamma$ is related to the
coefficients of the new terms in the Friedman equations. After discussing all
the Friedman equations for an arbitrary $\gamma$, we show how to recover the
standard scalings for dust and radiation. The acoustic scale $\ell_A$, related
to the peak positions in the pattern of the angular power spectrum of the
Cosmic Microwave Background anisotropies, is also computed and yields the
stringent bound $|\gamma|\ll 1$. We then argue that future data might be able
to distinguish this model from pure $\Lambda$CDM (corresponding to $\gamma=0$).
