Extra Dimensions and Varying Alpha
  I review recent constraints on and claimed detections of a time-varying fine-structure constant $\alpha$. Our results are consistent with no variation in $\alpha$ from the epoch of recombination to the present day, and restrict any such variation to be less than about 4%. The forthcoming MAP and Planck experiments will be able to break most of the currently existing degeneracies between $\alpha$ and other cosmological parameters, and measure $\alpha$ in the early universe with an accuracy comparable to current claimed recent-universe detections. 
C.J.A.P. Martins (CAUP (Porto), DAMTP (Cambridge), IAP (Paris))