At the rst stage of reheating after in ation, parametric resonance may rapidly transfer most of the energy of an in aton eld to the energy of other bosons. We show that quantum uctuations of scalar and vector elds produced at this stage are much greater than they would be in a state of thermal equilibrium. This leads to cosmological phase transitions of a new type, which may result in a copious...

We consider non-tachyonic hybrid inflation in the context of the braneworld cosmology. When one considers models for brane inflation, hybrid inflation is a natural consequence of the tachyon condensation if it appears at the end of inflation. In this case, however, reheating is a difficult problem due to the peculiar properties of the tachyon. In this paper we show some models for brane inflati...

We propose a model for early universe cosmology without the need for fundamental scalar fields. Cosmic acceleration and phenomenologically viable reheating of the universe results from a series of energy transitions, where during each transition vacuum energy is converted to thermal radiation. We show that this ‘cascading universe’ can lead to successful generation of adiabatic density fluctuat...

We study the impact for leptogenesis of new U(1) gauge bosons coupled to the heavy Majorana neutrinos. They can significantly enhance the efficiency of thermal scenarios in the weak washout regime as long as the Z ′ masses are not much larger than the reheating temperature (MZ′ < 10Trh), with the highest efficiencies obtained for Z ′ bosons considerably heavier than the heavy neutrinos (MZ′ & 1...

We study analytically the dynamical formation of lower dimensional branes at the endpoint of brane-antibrane inflation through the condensation of topological defects of the tachyon field which describes the instability of the initial state. We then use this information to quantify the efficiency of the reheating which is due to the coupling of time dependent tachyon background to massless gaug...

adverse reactions of streptokinase in patients with or without hydrocortisone injection nasiri m*1 , rahimian b2, bashiri t 3, salmalian f4 received: 25 april, 2010 accepted: 27 july, 2010 abstract background & aims: streptokinase is one of the most useful drugs in acute myocardial infarction. researches show that timely given injection of streptokinase decreases total mortality. allergic react...

We study numerically evolution of metric perturbations during reheating in a model with two fields and a strong parametric resonance. Our calculation is fully nonlinear and includes gravity but is restricted to spherical symmetry. In this model, super-Hubble metric perturbations can grow during reheating only due to effects nonlinear in fluctuations of the fields. We find that they indeed grow ...

UNLABELLED Polyamines are found in all groups of cyanobacteria, but their role in environmental adaptation has been barely investigated. In Synechocystis sp. strain PCC 6803, inactivation of spermidine synthesis genes significantly reduced the survivability under chill (5°C)-light stress, and the survivability could be restored by addition of spermidine. To analyze the effects of spermidine on ...