Running of the scalar spectral index in bouncing cosmologies
  We calculate the running of the scalar index in the ekpyrotic and matter
bounce cosmological scenarios, and find that it is typically negative for
ekpyrotic models, while it is typically positive for realizations of the matter
bounce where multiple fields are present. This can be compared to inflation,
where the observationally preferred models typically predict a negative
running. The magnitude of the running is expected to be between $10^{-4}$ and
up to $10^{-2},$ leading in some cases to interesting expectations for
near-future observations.
