Deconfinement transition in protoneutron stars: analysis within the Nambu-Jona-Lasinio model

We study the effect of color superconductivity and neutrino trapping on the deconfinement transition of hadronic matter into quark matter in a protoneutron star. To describe the strongly interacting matter a two-phase picture is adopted. For the hadronic phase we use different parameterizations of a non-linear Walecka model which includes the whole baryon octet. For the quark matter phase we use an $SU(3)_f$ Nambu-Jona-Lasinio effective model which includes color superconductivity. We impose color and flavor conservation during the transition in such a way that just deconfined quark matter is transitorily out of equilibrium with respect to weak interactions. We find that deconfinement is more difficult for small neutrino content and it is easier for lower temperatures although these effects are not too large. In addition they will tend to cancel each other as the protoneutron star cools and deleptonizes, resulting a transition density that is roughly constant along the evolution of the protoneutron star. According to these results the deconfinement transition is favored after substantial cooling and contraction of the protoneutron star

On the embedding of spacetime in five-dimensional Weyl spaces

We revisit Weyl geometry in the context of recent higher-dimensional theories of spacetime. After introducing the Weyl theory in a modern geometrical language we present some results that represent extensions of Riemannian theorems. We consider the theory of local embeddings and submanifolds in the context of Weyl geometries and show how a Riemannian spacetime may be locally and isometrically embedded in a Weyl bulk. We discuss the problem of classical confinement and the stability of motion of particles and photons in the neighbourhood of branes for the case when the Weyl bulk has the geometry of a warped product space. We show how the confinement and stability properties of geodesics near the brane may be affected by the Weyl field. We construct a classical analogue of quantum confinement inspired in theoretical-field models by considering a Weyl scalar field which depends only on the extra coordinate.Comment: 16 pages, new title and references adde

Oral health goes to school

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

Statistical models of mixtures with a biaxial nematic phase

We consider a simple Maier-Saupe statistical model with the inclusion of disorder degrees of freedom to mimic the phase diagram of a mixture of rod-like and disc-like molecules. A quenched distribution of shapes leads to the existence of a stable biaxial nematic phase, in qualitative agreement with experimental findings for some ternary lyotropic liquid mixtures. An annealed distribution, however, which is more adequate to liquid mixtures, precludes the stability of this biaxial phase. We then use a two-temperature formalism, and assume a separation of relaxation times, to show that a partial degree of annealing is already sufficient to stabilize a biaxial nematic structure.Comment: 11 pages, 2 figure

Effect of cyclosporin-A on the blood--retinal barrier permeability in streptozotocin-induced diabetes.

BACKGROUND: Our previous results showed that in retinas from streptozotocin (STZ)-induced diabetic rats there is an increased level of interleukin-1beta (IL-1beta). This cytokine may be involved in the expression of the inducible isoform of the nitric oxide synthase (iNOS), with consequent synthesis of large amounts of NO and blood-retinal barrier (BRB) breakdown. AIMS: The aim of this work was to examine whether the administration of cyclosporin-A (Cs-A) to STZ-induced diabetic rats inhibits the synthesis of IL-1beta and the expression of the inducible proteins, iNOS and cyclo-oxygenase-2 (COX-2) in retinal cells, and whether the activity of these proteins contribute to BRB breakdown. METHODS: The level of IL-1beta was evaluated by ELISA and the NO production by L-[3H]-citrulline formation. Expression of iNOS and COX-2 proteins was determined by two methods, western blot and immunohistochemistry. The permeability of the BRB was assessed by quantification of the vitreous protein. RESULTS AND DISCUSSION: Our results indicated that the levels of IL-1beta and NO in retinas from Cs-A-treated diabetic rats are significantly reduced, as compared to that in non-treated diabetic rats. The treatment of diabetic rats with Cs-A also significantly inhibited the expression of the inducible proteins, iNOS and COX-2. The evaluation of the vitreous protein content revealed that Cs-A also reduces the BRB permeability. Taken together, these results suggest that the increased production of the inflammatory mediators, IL-1beta and NO, in diabetes may affect the BRB permeability and therefore contribute to the development of diabetic retinopathy

Analysis and development of a localization system based on Radio Frequency

This paper presents an analysis on several strategies for location based on Radio-Frequency. The purpose of this study is to develop an infrastructure able to determine the position of a target within an area of 0.1 acres (aprox.11000 ft2 or 1000 m2) with an acceptable precision for the specific task. Along with the analysis of the many strategies and approaches on Radio- Location, this study tries to determine the best solution to implement a working system of location in an easy, secure and less expensive way, a solution able to be used in football field, without the use of large and/or expensive infrastructures like the Global Position System (G.P.S.) network

Development of an FIA system with amperometric detection for determination of bentazone in estuarine waters

On the basis of its electrochemical behaviour a new flow-injection analysis (FIA) method with amperometric detection has been developed for quantification of the herbicide bentazone (BTZ) in estuarine waters. Standard solutions and samples (200 µL) were injected into a water carrier stream and both pH and ionic strength were automatically adjusted inside the manifold. Optimization of critical FIA conditions indicated that the best analytical results were obtained at an oxidation potential of 1.10 V, pH 4.5, and an overall flow-rate of 2.4 mL min–1. Analysis of real samples was performed by means of calibration curves over the concentration range 2.5x10–6 to 5.0x10–5 mol L–1, and results were compared with those obtained by use of an independent method (HPLC). The accuracy of the amperometric determinations was ascertained; errors relative to the comparison method were below 4% and sampling rates were approximately 100 samples h–1. The repeatability of the proposed method was calculated by assessing the relative standard deviation (%) of ten consecutive determinations of one sample; the value obtained was 2.1%