We show that entropy perturbations can eliminate instabilities and oscillations, in the mass power spectrum of the quartessence Chaply-gin models. Our results enlarge the current parameter space of models compatible with large scale structure and cosmic microwave background (CMB) observations.
Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film… (More)
We revisit the kink-like parametrization of the deceleration parameter q(z) , which considers a transition, at redshift z t , from cosmic deceleration to acceleration. In this parametrization the initial, at z z t , value of the q-parameter is q i , its final, z = −1, value is q f and the duration of the transition is parametrized by τ. By assuming a… (More)