Signatures of quark deconfinement through the r-modes of twin stars

The observation and distinction of two compact stars with an identical mass but a different radius would be a clear sign of hadron-quark phase transition in nuclear matter. Motivated by studies searching for significant deviations in the observables of twin stars, we investigate the differences that manifest in their r-mode instability windows and spin-down evolution. Firstly, we obtain a set of hybrid equations of state (which predict the existence of a third stable branch of compact objects) by employing the well-known Maxwell construction within the phenomenological framework of constant speed of sound parametrization. Then, we systematically study the influence of certain parameters, such as the energy density jump (in the resulting hybrid equation of state) and the crust elasticity, on the deviations appearing in the r-mode instability windows and spin-down evolution of twin stars. We conclude that two stars with an identical mass and fairly similar spin frequency and temperature, may behave differently with respect to r-modes. Thus, the future possible detection of gravitational waves (due to unstable r-modes) from a star laying in the stable region of the frequency-temperature plane would be a strong indication for the existence of twin stars. Furthermore, we consider current data for the spin frequencies and temperatures of observed pulsars and compare them to the predictions made from equations of state employed in this study. We find that, depending on the transition density and the rigidness of the crust, hybrid equations of state may be a viable solution for the explanation of existing data.Comment: v1: 14 pages, 7 figures, 2 tables; v2: updated to match the published version; accepted for publication in Physical Review

Hybrid stars in light of the HESS J1731-347 remnant and the PREX-II experiment

The recent analysis on the central compact object in the HESS J1731-347 remnant suggests interestingly small values for its mass and radius. Such an observation favors soft nuclear models that may be challenged by the observation of massive compact stars. In contrast, the recent PREX-II experiment, concerning the neutron skin thickness of $^{208}$Pb, points towards stiff equations of state that favor larger compact star radii. In the present study, we aim to explore the compatibility between stiff hadronic equations of state (favored by PREX-II) and the HESS J1731-347 remnant in the context of hybrid stars. For the construction of hybrid equations of state we use three widely employed Skyrme models combined with the well-known vector MIT bag model. Furthermore we consider two different scenarios concerning the energy density of the bag. In the first case, that of a constant bag parameter, we find that the resulting hybrid equations of state are strongly disfavored by the observation of $\sim2 M_\odot$ pulsars. However, the introduction of a Gaussian density dependence yields results that are compatible with the conservative $2 M_\odot$ constraint. The utilization of recent data based on the observation of PSR J0030+0451, PSR J0952-0607 and GW190814 allows for the imposition of additional constraints on the relevant parameters and the stiffness of the two phases. Interestingly, we find that the derived hybrid equations of state do not satisfy the PSR J0030+0451 constraints in $1\sigma$ and only marginally agree with the $2\sigma$ estimations. In addition, we estimate that the observation of massive pulsars, like PSR~J0952-0607, in combination with the existence of HESS J1731-347, may require a strong phase transition below $\sim 1.7n_0$. Finally, we show that the supermassive compact object involved in GW190814 could potentially be explained as a rapidly rotating hybrid star.Comment: 15 pages, 15 figures, 6 table

Generalized cusp in AdS_4 x CP^3 and more one-loop results from semiclassical strings

We evaluate the exact one-loop partition function for fundamental strings whose world-surface ends on a cusp at the boundary of AdS_4 and has a "jump" in CP^3. This allows us to extract the stringy prediction for the ABJM generalized cusp anomalous dimension Gamma_{cusp}^{ABJM} (phi,theta) up to NLO in sigma-model perturbation theory. With a similar analysis, we present the exact partition functions for folded closed string solutions moving in the AdS_3 parts of AdS_4 x CP^3 and AdS_3 x S^3 x S^3 x S^1 backgrounds. Results are obtained applying to the string solutions relevant for the AdS_4/CFT_3 and AdS_3/CFT_2 correspondence the tools previously developed for their AdS_5 x S^5 counterparts.Comment: 48 pages, 2 figures, version 3, corrected misprints in formulas 2.12, B.86, C.33, added comment on verification of the light-like limi

Speed of sound bounds and first-order phase transitions in compact stars

In the present study we employ three distinct physically motivated speed of sound bounds in order to construct hybrid models where the high density phase is described by the maximally stiff equation of state. In particular, we consider the bounds related to special relativity, relativistic kinetic theory and conformality. The low density hadronic phase is described by a state-of-the-art microscopic relativistic Brueckner-Hartree-Fock theory. This work aims to access the effect of the different speed of sound constraints on the relevant parameter space of the key parameters of first-order phase transitions by utilising recent astronomical data. This involves a systematic analysis that also includes two distinct schemes for the construction of hybrid models, namely the Maxwell and Gibbs methods. Finally, a relevant discussion is conducted on the possible occurrence of a thermodynamic inconsistency that is related to the stability of the high density phase over hadronic matter at large densities.Comment: 11 pages, 8 Figure

Boas práticas de manipulação na merenda escolar da rede municipal de educação do município de Araguatins - TO

Trabalho apresentado no II Congresso Nacional do PROJETO RONDON, realizado em Florianópolis, SC, no período de 23 a 25 de setembro de 2015 - Universidade Federal de Santa Catarina.A alimentação é uma necessidade básica do ser humano, um fator primordial para o desenvolvimento corporal e intelectual. Deste modo, a merenda escolar deve oferecer alimentos que atendam necessidades nutricionais dos alunos durante sua permanência na escola, assim contribuindo para o desenvolvimento humano e aprendizagem e rendimento escolar. Atualmente a alimentação escolar é considerada uma das principais refeições do dia de muitas crianças, portanto é de extrema importância ter o máximo de cuidado ao manipular os alimentos oferecidos. Os cuidados com a merenda escolar devem ser realizados desde a escolha, a compra dos alimentos até a distribuição e elaboração. Os cuidados não devem somente ser realizados nas etapas de pré-preparo, preparo e pós-preparo dos alimentos, mas também na higiene pessoal do manipulador, a qual todos os indivíduo devem ter com o seu próprio corpo para conservar não só a sua saúde pessoal, mas também a saúde das demais pessoas. A higiene dos manipuladores é de extrema importância devido ao risco de contaminação cruzada que pode ocorrer nos alimentos, visto que, hoje a contaminação vem sendo uma das grandes preocupações dos órgãos governamentais devido ao alto índice de doenças transmitidas por alimentos que resultam em sérios danos a saúde dos consumidores e em alguns casos podem levar até a morte. Portanto foi realizada na cidade de Araguatins – TO uma oficina com as merendeiras e zeladoras das escolas municipais do município que teve como objetivo oferecer informações que auxiliassem os manipuladores a manusear os alimentos de forma correta para mantê-los saudáveis e seguros. Assim foi abordado como preparar um alimento saudável e seguro na merenda escolar, a importância do manipular os alimentos quanto a higiene pessoal, higienização de alimentos, utensílios e ambiente, conservação dos mantimentos. As atividades foram conduzidas com interações práticas entre ministrantes e ouvintes. Uma das maiores preocupações encontradas e abordadas pelos participantes foram a falta de recursos financeiros para as compras dos materiais básicos para higienização e o difícil acesso a água potável e luz em algumas comunidades e equipamentos para a refrigeração ao adequada dos alimentos. Assim o trabalho das merendeiras torna-se desafiador para a busca constante pela segurança e qualidade da merenda escolar. Com o trabalho conseguiu-se atingir o resultado de conscientização das necessidades básicas de higiene pessoal e alimentar nas merendeiras e zeladoras da cidade de Araguatins - TO, além da troca de informações das diferentes realidades que vivem as diferentes regiões do Brasil atualmente

The international face of Thessaloniki: the “Greek crisis,” the entrepreneurial mayor, and mainstream media discourses

Thessaloniki and its mayor have been portrayed quite favourably in international mainstream media compared to the Greek state after the 2008 economic crisis. The dominant (media) discourses on Greece interpret the crisis as the result of the failure of the Greek state to reform due to the prevalence of a traditional political culture over a modern one and the moral failures of the population. In the international media representations of Thessaloniki, the local government has been described as “exceptional” in its crisis management compared to the state and other local governments, and the city's mayor, Yiannis Boutaris, has been portrayed as a reform hero, due to the implemented entrepreneurial development strategy and the revamp of the city's image through place branding. Analysing the key role of international media in the production and reproduction of a place-branding campaign of Thessaloniki in international media by employing critical discourse analysis, the paper questions the favourable representations of the city compared to the Greek state during the same period. I argue that the serial repetition of positive images contributed to Thessaloniki being perceived as an example to be followed by other Greek local governments and the central state, acting as a best practice example for transformations envisioned on wider scales. The paper contributes to place-branding debates by illustrating the important role of international media in the dissemination of place brands, and by analysing how media representations of place may serve the legitimation of processes of neoliberalisation on scales wider than the concrete urban setting where they occur

Austerity-Driven Labour Market Reforms in Southern Europe: Eroding the Security of Labour Market Insiders

The sovereign debt crisis in the Eurozone and increased pressures for ‘structural reform’ have led to a period of intensive change in labour market policy in Southern Europe. Examining the cases of Greece, Portugal, Spain and Italy, this article focuses on the security of labour market insiders, a key group in labour markets that is highly segmented. Th e security of labour market insiders is conceptualised as consisting of security in employment (protection against dismissals) and security in unemployment (protection against drops in income provided by unemployment insurance and assistance). Using changes in national laws, the article charts and compares labour market change along these two dimensions across these four Southern European countries. Because labour market reform has not been restricted to Southern Europe, the article also compares these developments to broader changes in the countries of the Eurozone, using OECD and MISSOC data. Having demonstrated the degree to which the security of labour market insiders has diminished, the article concludes with an agenda for research on the policy dynamics of Southern European labour market reform in the wake of the fi nancial crisis

EU Aggregate Demand As a Way out of Crisis? Engaging the Post-Keynesian Critique: EU Aggregate Demand As a Way out of Crisis?

Post-Keynesians have delivered an important advance in providing explanations of the Eurozone Crisis, not the least in demonstrating how the formation of the European integration project lacked the means to manage effectively the macroeconomic imbalances between ‘core’ and ‘peripheral’ spaces across the region. Through a critical engagement with such descriptions, this article argues that to account more adequately for the formation of the asymmetrical and crisis-ridden forms of development across the Eurozone, it is necessary to focus on the uneven and combined development of Europe’s ‘peripheral’ spaces and their integration into an expanded free trade regime since the 1980s. It is through a focus on the structuring condition of uneven and combined development shaped by capitalist social relations of production and attendant class struggles that we can better locate the origins of the present crisis

Comparative analyses imply that the enigmatic sigma factor 54 is a central controller of the bacterial exterior

Contains fulltext : 95738.pdf (publisher's version ) (Open Access)BACKGROUND: Sigma-54 is a central regulator in many pathogenic bacteria and has been linked to a multitude of cellular processes like nitrogen assimilation and important functional traits such as motility, virulence, and biofilm formation. Until now it has remained obscure whether these phenomena and the control by Sigma-54 share an underlying theme. RESULTS: We have uncovered the commonality by performing a range of comparative genome analyses. A) The presence of Sigma-54 and its associated activators was determined for all sequenced prokaryotes. We observed a phylum-dependent distribution that is suggestive of an evolutionary relationship between Sigma-54 and lipopolysaccharide and flagellar biosynthesis. B) All Sigma-54 activators were identified and annotated. The relation with phosphotransfer-mediated signaling (TCS and PTS) and the transport and assimilation of carboxylates and nitrogen containing metabolites was substantiated. C) The function annotations, that were represented within the genomic context of all genes encoding Sigma-54, its activators and its promoters, were analyzed for intra-phylum representation and inter-phylum conservation. Promoters were localized using a straightforward scoring strategy that was formulated to identify similar motifs. We found clear highly-represented and conserved genetic associations with genes that concern the transport and biosynthesis of the metabolic intermediates of exopolysaccharides, flagella, lipids, lipopolysaccharides, lipoproteins and peptidoglycan. CONCLUSION: Our analyses directly implicate Sigma-54 as a central player in the control over the processes that involve the physical interaction of an organism with its environment like in the colonization of a host (virulence) or the formation of biofilm