The magnetic SW Sextantis star RX J1643.7+3402

We present time-resolved spectroscopy and circular spectropolarimetry of the SW Sex star RX J1643.7+3402. We find significant polarisation levels exhibiting a variability at a period of 19.38 +- 0.39 min. In addition, emission-line flaring is found predominantly at twice the polarimetric period. These two findings are strong evidences in favour of the presence of a magnetic white dwarf in the system. We interpret the measured periodicities in the context of our magnetic accretion model for SW Sex stars. In contrast with LS Pegasi -the first SW Sex star discovered to have modulated circular polarisation- the polarisation in RX J1643.7+3402 is suggested to vary at 2(omega - Omega), while the emission lines flare at (omega - Omega). However, a 2omega/omega interpretation cannot be ruled out. Together with LS Peg and V795 Her, RX J1643.7+3402 is the third SW Sex star known to exhibit modulated circular polarisation.Comment: 7 pages, 4 figures, accepted for publication in MNRA

Effect of the Gribov horizon on the Polyakov loop and vice versa

We consider finite temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger (GZ) quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanziger quantization procedure in order to illustrate the approach and the potential direct link between the vacuum structure of the theory (dynamical mass scales) and (de)confinement. We also present a first look at the critical temperature obtained from the Refined Gribov-Zwanziger approach. Finally, a particular problem for the pressure at low temperatures is reported.Comment: 19 pages, 8 .pdf figures. v2: extended section 3 + extra references; version accepted for publication in EPJ

Correction of artificial jumps in the historical geomagnetic measurements of Coimbra Observatory, Portugal

The Coimbra Magnetic Observatory (International Association of Geomagnetism and Aeronomy code COI) in Portugal has a long history of observation of the geomagnetic field, spanning almost 150 yr since the first geomagnetic measurements in 1866. These long instrumental geomagnetic records provide very important information about variability of geomagnetic elements and indices, their trends and cycles, and can be used to improve our knowledge on the sources that drive variations of the geomagnetic field: liquid core dynamics (internal) and solar forcing (external). <br><br> However, during the long life of the Coimbra Observatory, some inevitable changes in station location, instrument's park and electromagnetic environment have taken place. These changes affected the quality of the data collected at COI causing breaks and jumps in the series of geomagnetic field components and local K index. Clearly, these inhomogeneities, typically shift-like (step-like) or trend-like, have to be corrected or, at least, minimized in order for the data to be used in scientific studies or to be submitted to international databases. <br><br> In this study, the series of local K index and declination of the geomagnetic field are analysed: the former because it allows direct application of standard homogenization methods and the latter because it is the longest continuous series produced at COI. For the homogenization, visual and statistical tests (e.g. standard normal homogeneity test) have been applied directly to the local geomagnetic K index series (from 1951 to 2012). The homogenization of the monthly averages of declination (from 1867 to 2012) has been done using visual analysis and statistical tests applied to the time series of the first differences of declination values, as an approximation to the first time derivative. This allowed not only estimating the level of inhomogeneity of the studied series but also detecting the highly probable homogeneity break points. These points have been cross-checked with the metadata, and the COI series have been compared with reference series from the nearest geomagnetic stations and, in the case of declination series, from the recent geomagnetic field model COV-OBS to set up the required correction factors. As a result, the homogenized series measured in COI are considered to be essentially free of artificial shifts starting from the second half of the 20th century, and ready to be used by the scientific community

Double non-perturbative gluon exchange: an update on the soft Pomeron contribution to pp scattering

We employ a set of recent, theoretically motivated, fits to non-perturbative unquenched gluon propagators to check in how far double gluon exchange can be used to describe the soft sector of pp scattering data (total and differential cross section). In particular, we use the refined Gribov--Zwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwall-type gluon propagator (as motivated from Dyson-Schwinger equations) in conjunction with a perturbative quark-gluon vertex, next to a model based on the non-perturbative quark-gluon Maris-Tandy vertex, popular from Bethe-Salpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with "older" ISR and more recent TOTEM and ATLAS data. The lower the value of total energy \sqrt{s}, the better the results appear to be.Comment: 14 pages, 8 .pdf figures. To appear in Phys.Rev.

Contribuição para o controlo da infeção nosocomial de Candida parapsilosis por tipagem com marcadores de DNA microssatélite

Fungal infections constitute a relevant problem in hospitals from all over the world. Their easy transmission through the air, water, or by direct or indirect contact with contaminated persons, surfaces or objects lead to an increasing preoccupation with those infections, particularly in immunocompromised patients. Regarding the enormous importance of Candida parapsilosis as agent of bloodstream infections and hospital outbreaks, the presented work aimed to contribute to the development of new molecular tools able to answer to epidemiological questions related with infections by this species and their application in favor of patient safetyAs infecções fúngicas constituem um problema hospitalar relevante em todo o mundo. A fácil transmissão dos fungos pelo ar, água ou pelo contato direto ou indireto com pessoas, superfícies ou objetos contaminados conduz a uma crescente preocupação com este tipo de infecções, principalmente em pacientes imunocomprometidos. Considerando a grande relevância da levedura Candida parapsilosis em Portugal como agente etiológico de infecções sistémicas e de surtos hospitalares, o trabalho apresentado teve como objetivo contribuir para o desenvolvimento de novas ferramentas moleculares que permitissem responder a questões epidemiológicas relacionadas com esta espécie e posterior aplicação desta ferramenta em prol da segurança do paciente

Quark-hadron phase transition in a neutron star under strong magnetic fields

We study the effect of a strong magnetic field on the properties of neutron stars with a quark-hadron phase transition. It is shown that the magnetic field prevents the appearance of a quark phase, enhances the leptonic fraction, decreases the baryonic density extension of the mixed phase and stiffens the total equation of state, including both the stellar matter and the magnetic field contributions. Two parametrisations of a density dependent static magnetic field, increasing, respectively, fast and slowly with the density and reaching $2-4\times 10^{18}$G in the center of the star, are considered. The compact stars with strong magnetic fields have maximum mass configurations with larger masses and radius and smaller quark fractions. The parametrisation of the magnetic field with density has a strong influence on the star properties.Comment: 15 pages, 6 figures, 8 tables, accepted for publication in J. Phys.

Antecipação da experiência de parto : mudanças desenvolvimentais ao longo da gravidez

Este estudo foi desenvolvido com o intuito de: 1) conhecer o modo como durante a gravidez a mulher antecipa algumas dimensões relevantes da experiência de parto (tais como: 1) planeamento e preparação; 2) expectativas quanto ao medo, confiança, controlo e intensidade da dor; 3) preocupação com o bem-estar próprio e do bebé; 4) suporte esperado por parte de pessoas significativas; 5) antevisão dos cuidados maternos); 2) averiguar a presença de mudanças na antecipação do parto, em dois momentos sucessivos da gravidez (no 2º trimestre e no 3º trimestre); 3) identificar diferenças na antecipação da experiência de parto, atendendo a características sociais e demográficas das participantes. A amostra é constituída por 163 grávidas primiparas, utentes da Maternidade Júlio Dinis (Porto), e foi seleccionada aleatoriamente, tendo em conta os seguintes critérios: saber ler e escrever, primiparidade, gestação entre as 20 e as 24 semanas. Entre a 20ª e a 24ª semanas de gravidez administrou-se a Parte Social e Demográfica da Versão Portuguesa da Contextual Assessment of the Maternity Experience (CAME, Bernazzani, Marks, Siddle, Asten, Bifulco, et al., 2003), composta por 45 questões abertas, focadas na recolha de dados sociais e demográficos relativos à grávida e ao companheiro, bem como história obstétrica e psicopatológica da utente. Em dois momentos sucessivos, entre a 20ª e a 24ª semanas de gestação (2º trimestre) e entre a 30ª e a 36ª semanas de gestação (3º trimestre) as participantes preencheram o Questionário de Antecipação do Parto (QAP, Costa, Figueiredo, Pacheco, & Pais, in press), constituído por 58 questões de auto-relato relativas à antecipação da experiência de trabalho de parto, parto e pós-parto. Os resultados indicam que no 2º trimestre a generalidade das grávidas planeia e antecipa suporte por parte de pessoas significativas no parto, tem uma visão positiva das suas competências maternas e está moderadamente preocupada com o bem estar próprio e o do bebé. A maioria antevê, contudo, uma experiência de parto dolorosa, as previsões dividem-se entre o medo e, a confiança e o controlo. A comparação entre o 2º e o 3º trimestre de gravidez revela que, no 3º trimestre, a mãe está mais focada no parto, tem níveis superiores de planeamento e conhecimento acerca da situação, mas antecipa a experiência como mais dolorosa, assim como prevê menor confiança e controlo e mais medo no parto, e preocupa-se mais com possíveis consequências negativas no seu bem estar e do bebé. Simultaneamente podemos averiguar algumas características sociais e demográficas que resultam em maiores dificuldades para a mãe na adequada antecipação do parto, no 2º e 3º trimestres de gestação, tais como menor idade, baixo nível de escolaridade, profissões de reduzida qualificação, agregados familiares alargados ou no qual o companheiro está ausente. Em conclusão, entre outros aspectos, este estudo dá conta de mudanças desenvolvimentais que ocorrem durante a gravidez e alerta para a necessidade de dedicar mais atenção à preparação para o parto, sobretudo junto de grávidas pertencentes a determinados estratos sociais e económicos, sugerindo ainda áreas relevantes para essa preparação.This study was developed in order to: 1) understand how during pregnancy woman anticipates their childbirth experience, in terms of some relevant dimensions (such as: 1) planning and preparation; 2) expectations of fear, trust, control and pain intensity; 3) worry with the own and infant well-being; 4) support from significant others; 5) maternal care); 2) to know about changes in the perception of the delivery experience across pregnancy (between the 2nd and 3rd trimester); to analyze differences on the childbirth experience anticipation according to the socio demographic characteristics of the participants. The sample is constituted by 163 primiparous women, who can write and read Portuguese, and are attending the Júlio Dinis Maternity Hospital (MJD, Porto). Between the 20th and the 24th weeks of pregnancy the Social and Demographic part of the Portuguese Version of the Contextual Assessment of the Maternity Experience (CAME, Bernazzani, Marks, Siddle, Asten, Bifulco, et al., 2003), composed by 45 open questions regarding social and demographic data about the mother and her partner, as well as about the obstetric and medical history, was administrated. In two successive moments, between the 20th and the 24th weeks of pregnancy (2nd trimester) and between the 30th and the 36th weeks of pregnancy (3rd trimester), the participants had fulfilled the Childbirth Experience Anticipation Questionnaire (Questionário de Antecipação do Parto, QAP, Costa, Figueiredo, Pacheco, & Pais, in press), a 58 items self-report questionnaire about the perception of labour, delivery and postpartum experience. The results shows that during the 2nd trimester of pregnancy the mothers are generally planning the delivery and have positive expectations about the support from significant others, as well as about theirs own maternal competences; they usually also are worry about their own and their infant’s well-being. The majority anticipates a painful delivery experience and split between expecting fear, and trust and control during delivery. Comparisons between the 2nd and 3rd pregnancy trimester shows that, in the 3rd trimester mothers are more focus in labour and have higher levels of planning and knowledge about the situation, but they also anticipates a more painful experience, as well as less trust and control and more fear, and are more worried about the negative consequences on her and on the baby. Some social and demographic characteristics are associated with the mother’s difficulty on an adequate childbirth anticipation experience during the 2nd and 3rd trimesters, such as: less age, lower educational level, reduced qualification professions and larger families or families without the partner. This study describes some important developmental changes occurring during pregnancy and also alerts for the need of implementing better childbirth preparation (especially for mothers with some social and economic characteristics), suggesting the most important areas for that