Gravastars and Black Holes of Anisotropic Dark Energy

Dynamical models of prototype gravastars made of anisotropic dark energy are constructed, in which an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\gamma)\sigma$ divides the whole spacetime into two regions, the internal region filled with a dark energy fluid, and the external Schwarzschild region. The models represent "bounded excursion" stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes. Here we show, for the first time in the literature, a model of gravastar and formation of black hole with both interior and thin shell constituted exclusively of dark energy. Besides, the sign of the parameter of anisotropy ($p_t - p_r$) seems to be relevant to the gravastar formation. The formation is favored when the tangential pressure is greater than the radial pressure, at least in the neighborhood of the isotropic case ($\omega=-1$).Comment: 16 pages, 8 figures. Accepted for publication in Gen. Rel. Gra

Combining high-value biotechnological processes: from wastewaters bioremediation to bacterial bioenergy feedstock production

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] The significant increase of global industrialization has been promoting the generation of large amounts of residues and wastewaters. In particular, oily wastewaters (contaminated with hydrocarbons) must be considered, since their disposal into the surrounding environments can represent a serious threat to several types of environmental resources. Simultaneously, the drastic depletion of fossil fuel resources demands for search of alternative feedstocks with environmental and economic advantages. Therefore, the production of bacterial lipids using inexpensive substrates, as wastes, has attracted much attention. Hydrocarbonoclastic bacteria are important players in bioremediation of hydrocarbon contaminated wastewaters with additional capacity for the accumulation of storage lipids such as triacylglycerols and wax esters [1, 2]. These compounds are relevant raw materials for biofuels and oleochemicals production. [...]info:eu-repo/semantics/publishedVersio

Revisiting Clifford algebras and spinors III: conformal structures and twistors in the paravector model of spacetime

This paper is the third of a series of three, and it is the continuation of math-ph/0412074 and math-ph/0412075. After reviewing the conformal spacetime structure, conformal maps are described in Minkowski spacetime as the twisted adjoint representation of the group Spin_+(2,4), acting on paravectors. Twistors are then presented via the paravector model of Clifford algebras and related to conformal maps in the Clifford algebra over the lorentzian R{4,1}$ spacetime. We construct twistors in Minkowski spacetime as algebraic spinors associated with the Dirac-Clifford algebra Cl(1,3)(C) using one lower spacetime dimension than standard Clifford algebra formulations, since for this purpose the Clifford algebra over R{4,1} is also used to describe conformal maps, instead of R{2,4}. Although some papers have already described twistors using the algebra Cl(1,3)(C), isomorphic to Cl(4,1), the present formulation sheds some new light on the use of the paravector model and generalizations.Comment: 17 page

Respiratory and non-respiratory outcomes of bronchopulmonary dysplasia in adolescents: A systematic review

Background: There is lack of evidence synthesis on the global consequences of bronchopulmonary dysplasia (BPD) in adolescence. Aim: Assess the impact of bronchopulmonary dysplasia on respiratory and non-respiratory outcomes in adolescents.Methods: A systematic review of studies assessing the outcomes of adolescents aged 10 to 19 years-old with BPD was conducted. We independently screened studies published until 6th March 2023 in PubMed (R) and Scopus (R) databases. Data on methodologic design, sample descriptive and findings were extracted from each study. Risk of bias was assessed using quality assessment tools.Results: Thirty-one studies were included. Adolescents with a history of BPD present with more respiratory symptoms (wheezing, respiratory exacerbations, need for respiratory medication) and twenty-five studies showed a reduction in pulmonary function, with varying impact according to BPD severity and no differences before and after the surfactant era. Spirometry evaluation throughout the years is not consensual, but meth-acholine and salbutamol response in BPD groups is increased compared to non-BPD groups. Markers of eosin-ophilic airway inflammation are not increased as in asthma patients. Exercise potential is identical, but data regarding physical capacity and activity are inconsistent. More frequent radiologic abnormalities translate into higher high-resolution computed tomography scores, with linear (72.2 %) and triangular subpleural opacities (58.3 %) as the most common findings. There is a higher risk for special needs in education, but quality of life seems to be equal to non-BPD adolescents.Conclusions: BPD negatively impacts both pulmonary and non-pulmonary outcomes in adolescents

FM 047-02: a collisional pair of galaxies with a ring

Aims. We investigate the nature of the galaxy pair FM 047-02, which has been proposed as an archetype of the Solitaire types of peculiar (collisional) ring galaxies. Methods. The study is based on long-slit spectrophotometric data in the range of 3500-9500 angstrons obtained with the Gemini Multi-ObjectComment: 07 pages, 06 figures, 02 tables. arXiv admin note: text overlap with arXiv:1206.071

Frequência do polimorfismo F200Y no gene da b-tubulina em em rebanhos ovinos do Estado de São Paulo.

A ovinocultura é uma atividade econômica que está em crescimento na maioria dos Estados brasileiros, inclusive em São Paulo. Um dos maiores entraves na criação de ovinos a pasto é a alta prevalência de helmintos gastrintestinais, dentre os quais se destaca o . Além disso, o controle das helmintoses gastrintestinais tem sido dificultado em função da resistência que os parasitas adquirem aos produtos químicos. Estudos demonstraram correlação entre a resistência ao benzimidazol (BZD) e a mutação no isotipo 1 do gene da b-tubulina, em que a transversão T > A leva à substituição do aminoácido fenilalanina por tirosina na posição 200 (F200Y). Assim, o presente trabalho teve como objetivo conhecer a frequência do polimorfismo F200Y no gene da -tubulina em isolados de 33 rebanhos ovinos do Estado de São Paulo. Após coleta de fezes para exame de OPG, realização de teste de redução de contagem de ovos nas fezes (TRCOF) e coprocultura, as larvas obtidas foram destinadas à extração de DNA com solvente orgânico e à genotipagem por -PCR e ARMS-PCR. As frequências genotípicas foram comparadas pelo teste de ² (10% de probabilidade) e testadas para o equilíbro de Hardy-Weinberg, (princípio que afirma que se nenhum fator evolutivo ocorrer em uma população, as frequências gênicas e genotípicas permanecem constantes através das gerações nas diferentes populações) no programa Genepop (http://genepop.curtin.edu.au/). As frequências do genótipo homozigoto AA (resistência) variaram de 0 a 66,7%; do genótipo heterozigoto AT (susceptibilidade), de 5,9 a 77,3%; e do genótipo homozigoto TT (susceptibilidade), de 0 a 83,3%. No TRCOF não foram encontradas propriedades com helmintos susceptíveis ao BZD, no entanto, para duas propriedades com baixa resistência ao BZD foram encontradas frequências do genótipo de resistência (AA) de 20,0% e 28,6%, enquanto que para 26 propriedades com resistência ao BZD, a frequência do mesmo genótipo variou de 0 a 66,7%. Dessa maneira, não foi possível verificar associação entre o polimorfismo F200Y e o estado de resistência ao BZD. Observamos que a maioria das populações encontrou-se em equilíbrio de Hardy-Weinberg (p>0,05), exceto cinco propriedades com excesso de homozigotos, e uma propriedade com excesso de heterozigotos. Assim, pode-se inferir que, nas propriedades em equilíbrio de Hardy-Weinberg, o polimorfismo F200Y não se encontrava sob pressão de seleção, ou seja, não estava sendo selecionado pelos tratamentos com anti-helmínticos. Além disso, devido à grande frequência de propriedades com resistência múltipla aos cinco antihelmínticos estudados (ivermectina, benzimidazol, levamisol, moxidectina e closantel), pode-se inferir que outros polimorfismos, nesse ou em outros genes, podem ser responsáveis tanto pela resistência ao BZD, quanto pela resistência múltipla a vários antihelmínticos observada nos diferentes rebanhos ovinos do Estado de São Paulo