Back-reaction effect in power-law inflation
  I consider a power-law inflationary model taking into account back-reaction effects. The interesting result is that the spectrum for the scalar field fluctuations does not depends on the expansion rate of the universe $p$ and that it result to be scale invariant for cosmological scales. However, the amplitude for these fluctuations depends on $p$. 
Mauricio Bellini (Mar del Plata University & CONICET)