Strongly Coupled Chameleon Fields: New Horizons in Scalar Field Theory

We show that as a result of non-linear self-interactions, scalar field theories that couple to matter much more strongly than gravity are not only viable but could well be detected by a number of future experiments, provided these are properly designed to do so.Comment: 4 pages, 3 figs. Typos corrected. Comments added. Phys. Rev. Lett. in prin

Estado Confusional Agudo após Corticoterapia Inalada

Background: The connection between corticotherapy and neuropsychiatric symptoms is widely known, being one of the first questions we need to assess when presenting with first episode psychiatric symptoms or confusional state. Aims: To date, data on cases related to inhaled corticotherapy and neuropsychiatric effects is scarce. In this paper we describe a rare case in a young woman. Methods: The clinical case presented led us to try to understand the data published on the subject in order to discuss it in greater length. Results and Conclusions: We present and discuss a 27-year-old patient’s case, with no previous psychiatric disease, who was admitted to our Psychiatric ward after the onset of severe acute behavioural disturbance characterized by aggressiveness, visual and auditory hallucinatory activity, misidentification and altered conscience status. It was later found that seven days earlier she had been prescribed inhaled corticotherapy for a minor respiratory infection. A few days after corticotherapy withdrawal, the clinical symptoms improved significantly.info:eu-repo/semantics/publishedVersio

An analytic model for the transition from decelerated to accelerated cosmic expansion

We consider the scenario where our observable universe is devised as a dynamical four-dimensional hypersurface embedded in a five-dimensional bulk spacetime, with a large extra dimension, which is the {\it generalization of the flat FRW cosmological metric to five dimensions}. This scenario generates a simple analytical model where different stages of the evolution of the universe are approximated by distinct parameterizations of the {\it same} spacetime. In this model the evolution from decelerated to accelerated expansion can be interpreted as a "first-order" phase transition between two successive stages. The dominant energy condition allows different parts of the universe to evolve, from deceleration to acceleration, at different redshifts within a narrow era. This picture corresponds to the creation of bubbles of new phase, in the middle of the old one, typical of first-order phase transitions. Taking $\Omega_{m} = 0.3$ today, we find that the cross-over from deceleration to acceleration occurs at $z \sim 1-1.5$, regardless of the equation of state in the very early universe. In the case of primordial radiation, the model predicts that the deceleration parameter "jumps" from $q \sim + 1.5$ to $q \sim - 0.4$ at $z \sim 1.17$. At the present time $q = - 0.55$ and the equation of state of the universe is $w = p/\rho \sim - 0.7$, in agreement with observations and some theoretical predictions.Comment: The abstract and introduction are improved and the discussion section is expanded. A number of references are adde