Search

The photometric time series of solar-like stars can exhibit rotational modulation due to active regions co-rotating with the stellar surface, allowing us to constrain stellar rotation and magnetic activity. In this work we investigate the behavior, particularly the variability, of the photometric magnetic activity of Kepler solar-like stars and compare it with that of the Sun. We adopted the photometric magnetic activity proxy Sph, which was computed with a cadence of 5 x the rotation period, Prot. The average Sph was taken as the mean activity level, and the standard deviation was taken as a measure of the temporal variation of the magnetic activity over the observations. We also analyzed Sun-as-a-star photometric data from VIRGO. Sun-like stars were selected from a very narrow parameter space around the solar properties. We also looked into KIC 8006161 (HD 173701), an active metal-rich G dwarf, and we compared its magnetic activity to that of stars with similar stellar parameters. We find that the amplitude of Sph variability is strongly correlated with its mean value, independent of spectral type. An equivalent relationship has been found for ground-based observations of chromospheric activity emission and magnetic field strength, but in this work we show that photometric Kepler data also present the same behavior. While, depending on the cycle phase, the Sun is among the less active stars, we find that the solar Sph properties are consistent with those observed in Kepler Sun-like stars. KIC 8006161 is, however, among the most active of its peers, which tend to be metal-rich. This results from an underlying relationship between Prot and metallicity and supports the following interpretation of the magnetic activity of KIC 8006161: its strong activity is a consequence of its high metallicity, which affects the depth of the convection zone and, consequently, the efficiency of the dynamo., Published in A&A; 12 pages including 11 figures and 3 tables (main text); 10 additional pages including 17 figures and 5 tables (appendix)

We developed, tested and validated a new Fast, Robust and Automated (FRA) tool to detect solar-like oscillations. FRA is based on the detection and measurement of the frequency of maximum oscillation power $\nu_{max}$, without relying on the detection of a regular frequency spacing to guide the search. We applied the FRA pipeline to 254 synthetic power spectra representative of TESS red giants, as well as 1689 red giants observed by Kepler and 2344 red giants observed by TESS. We obtain a consistency rate for $\nu_{max}$ compared with existing measurements of $\sim$ 99% for Kepler red giants and of $\sim$ 98% for TESS red giants. We find that using $\nu_{max}$ as an input parameter to guide the search for the large frequency separation $\Delta\nu$ through the existing Envelope AutoCorrelation Function (EACF) method significantly improves the consistency of the measured $\Delta\nu$ in the case of TESS stars, allowing to reach a consistency rate above 99%. Our analysis reveals that we can expect to get consistent $\nu_{max}$ and $\Delta\nu$ measurements while minimizing both the false positive measurements and the non-detections for stars with a minimum of four observed sectors and a maximum G magnitude of 9.5., Comment: 35 pages, 17 figures. Accepted for publication in Astronomische Nachrichten. This is the pre-peer reviewed (submitted) version

Detailed understanding of stellar physics is essential towards a robust determination of stellar properties (e.g. radius, mass, and age). Among the vital input physics used in the modelling of solar-type stars which remain poorly constrained, is the initial helium abundance. To this end, when constructing stellar model grids, the initial helium abundance is estimated either (i) by using the semi-empirical helium-to-heavy element enrichment ratio, (ΔY/ΔZ), anchored to the standard big bang nucleosynthesis value, or (ii) by setting the initial helium abundance as a free variable. Adopting 35 low-mass, solar-type stars with multiyear Kepler photometry from the asteroseismic ‘LEGACY’ sample, we explore the systematic uncertainties on the inferred stellar parameters (i.e. radius, mass, and age) arising from the treatment of the initial helium abundance in stellar model grids. The stellar masses and radii derived from grids with free initial helium abundance are lower compared to those from grids based on a fixed ΔY/ΔZ ratio. We find the systematic uncertainties on mean density, radius, mass, and age arising from grids which employ a fixed value of ΔY/ΔZ and those with free initial helium abundance to be ∼ 0.9 per cent, ∼ 2 per cent, ∼ 5 per cent, and ∼ 29 per cent, respectively. We report that the systematic uncertainties on the inferred masses and radii arising from the treatment of initial helium abundance in stellar grids lie within the expected accuracy limits of ESA’s PLATO, although this is not the case for the age. © 2020 The Author(s)., The authors acknowledge the dedicated team behind the NASA'S Kepler missions. BN thanks Verma Kuldeep, Achim Weiss, and the Stellar Evolution research group at Max-Planck-Institut fur Astrophysik (MPA) for the useful comments on this article. BN also acknowledges postdoctoral funding from the Alexander von Humboldt Foundation. AGH, JCS, and BN acknowledge funding support from Spanish public funds (including FEDER funds) for research under projects ESP2017-87676-C5-2-R and ESP2017-87676-C5-5-R. TLC acknowledges support from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 792848 (PULSATION). JF wishes to honor the memory of Johannes Andersen, recently passed way. JF acknowledges funding from POCH and Portuguese FCT grant SFRH/BSAB/143060/2018. CITEUC is funded by National Funds through FCT - Foundation for Science and Technology (projects UID-PB/00611/2020). MSC is supported by national funds through Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) - in the form of a work contract and through the research grants UIDB/04434/2020, UIDP/04434/2020, and PTDC/FIS-AST/30389/2017, and by FEDER -Fundo Europeu de Desenvolvimento Regional through COMPETE2020 Programa Operacional Competitividade e Internacionalizacao (grant: POCI-01-0145-FEDER-030389). AGH also acknowledges support from 'FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento' under project E-FQM-041-UGR18 by Universidad de Granada. JCS also acknowledges support from project RYC-2012-09913 under the 'Ramon y Cajal' program of the Spanish Ministry of Science and Education. JC is funded by the Fundamental Research Funds for the Central Universities (grant: 19lgpy278). BA acknowledges support from the FCT PhD programme PD/BD/135226/2017. We thank the reviewer for the constructive remarks.

In this paper we study the possibility of non-relativistic quantum particles to traverse the generalized Ellis-Bronnikov wormholes by considering quantum effects, such as tunneling. We have used the generalized Ellis-Bronnikov wormhole metric and found that for $n=2$ we have a single barrier shaped effective potential centered at the throat of the wormhole for any value of orbital angular momentum. For $n\neq2$ we have a symmetric double barrier shaped potential when the orbital angular momentum is zero and a single barrier for nonzero angular orbital momentum. Analytical solutions for the Schr\"{o}dinger equation in the generalized Ellis-Bronnikov spacetime could be found only for $n=2$. Such solutions were given in terms of the confluent Heun functions. Finally, by using a delta-barrier approximation we could find the transmission and reflection coefficients for a non-relativistic particle to traverse the generalized Ellis-Bronnikov wormhole., Comment: 5 pages, two columuns, 3 figures

The space-borne missions CoRoT and Kepler have revealed numerous mixed modes in red-giant stars. These modes carry a wealth of information about red-giant cores, but are of limited use when constraining rapid structural variations in their envelopes. This limitation can be circumvented if we have access to the frequencies of the pure acoustic dipolar modes in red giants, i.e. the dipole modes that would exist in the absence of coupling between gravity and acoustic waves. We present a pilot study aimed at evaluating the implications of using these pure acoustic mode frequencies in seismic studies of the helium structural variation in red giants. The study is based on artificial seismic data for a red-giant-branch stellar model, bracketing seven acoustic dipole radial orders around vmax. The pure acoustic dipole-mode frequencies are derived from a fit to the mixed-mode period spacings and then used to compute the pure acoustic dipole-mode second differences. The pure acoustic dipole-mode second differences inferred through this procedure follow the same oscillatory function as the radial modes second differences. The additional constraints brought by the dipolar modes allow us to adopt a more complete description of the glitch signature when performing the fit to the second differences. The amplitude of the glitch retrieved from this fit is 15% smaller than that from the fit based on the radial modes alone. Also, we find that thanks to the additional constraints, a bias in the inferred glitch location, found when adopting the simpler description of the glitch, is avoided., Comment: 7 pages, 4 figures, accepted for publication in the MNRAS

Asteroseismology is a powerful tool to infer fundamental stellar properties. The use of these asteroseismic-inferred properties in a growing number of astrophysical contexts makes it vital to understand their accuracy. Consequently, we performed a hare-and-hounds exercise where the hares simulated data for 6 artificial main-sequence stars and the hounds inferred their properties based on different inference procedures. To mimic a pipeline such as that planned for the PLATO mission, all hounds used the same model grid. Some stars were simulated using the physics adopted in the grid, others a different one. The maximum relative differences found (in absolute value) between the inferred and true values of the mass, radius, and age were 4.32 per cent, 1.33 per cent, and 11.25 per cent, respectively. The largest systematic differences in radius and age were found for a star simulated assuming gravitational settling, not accounted for in the model grid, with biases of -0.88 per cent (radius) and 8.66 per cent (age). For the mass, the most significant bias (-3.16 per cent) was found for a star with a helium enrichment ratio outside the grid range. Moreover, a ~7 per cent dispersion in age was found when adopting different prescriptions for the surface corrections or shifting the classical observations by $\pm 1\sigma$. The choice of the relative weight given to the classical and seismic constraints also impacted significantly the accuracy and precision of the results. Interestingly, only a few frequencies were required to achieve accurate results on the mass and radius. For the age the same was true when at least one $l=2$ mode was considered., Comment: Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Rotational modulation of stellar light curves due to dark spots encloses information on spot properties and, thus, on magnetic activity. In particular, the decay of the autocorrelation function (ACF) of light curves is presumed to be linked to spot/active-region lifetimes, given that some coherence of the signal is expected throughout their lifetime. In the literature, an exponential decay has been adopted to describe the ACF. Here, we investigate the relation between the ACF and the active-region lifetimes. For this purpose, we produce artificial light curves of rotating spotted stars with different observation, stellar, and spot properties. We find that a linear decay and respective timescale better represent the ACF than the exponential decay. We therefore adopt a linear decay. The spot/active-region timescale inferred from the ACF is strongly restricted by the observation length of the light curves. For 1-year light curves our results are consistent with no correlation between the inferred and the input timescales. The ACF decay is also significantly affected by differential rotation and spot evolution: strong differential rotation and fast spot evolution contribute to a more severe underestimation of the active-region lifetimes. Nevertheless, in both circumstances the observed timescale is still correlated with the input lifetimes. Therefore, our analysis suggests that the ACF decay can be used to obtain a lower limit of the active-region lifetimes for relatively long-term observations. However, strategies to avoid or flag targets with fast active-region evolution or displaying stable beating patterns associated with differential rotation should be employed., 12 pages, 19 Figures, Accepted for publication in MNRAS

Magnetic fields influence the formation and evolution of stars and impact the observed stellar properties. Ap stars (magnetic A-type stars) are a prime example of this. Access to precise and accurate determinations of their stellar fundamental properties, such as masses and ages, is crucial to understand the origin and evolution of fossil magnetic fields. We propose using the radii and luminosities determined from interferometric measurements, in addition to seismic constraints when available, to infer fundamental properties of 14 Ap stars pr\'eviously characterised. We used a grid-based modelling approach, employing stellar models computed with the \textsc{cestam} stellar evolution code, and the parameter search performed with the \textsc{aims} optimisation method. The stellar model grid was built using a wide range of initial helium abundances and metallicities in order to avoid any bias originating from the initial chemical composition. The large frequency separations ($\Delta\nu$) of HR\,1217 (HD\,24712) and $\alpha$~Cir (HD\,128898), two rapidly oscillating Ap stars of the sample, were used as seismic constraints. We inferred the fundamental properties of the 14 stars in the sample. The overall results are consistent within $1\sigma$ with previous studies, however, the stellar masses inferred in this study are higher. This trend likely originates from the broader range of chemical compositions considered in this work. We show that the use of $\Delta\nu$ in the modelling significantly improves our inferences, allowing us to set reasonable constraints on the initial metallicity which is, otherwise, unconstrained. This gives an indication of the efficiency of atomic diffusion in the atmospheres of roAp stars and opens the possibility of characterising the transport of chemical elements in their interiors., Comment: 19 pages, 14 figures, accepted for publication in A&A

Background Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has become an increasingly popular method for lumbar arthrodesis. While having similar long-term outcomes when compared with open TLIF, it decreases the amount of intraoperative blood loss and iatrogenic muscle damage, the intensity of postoperative pain, and the duration of hospital stay. However, uncertainty remains about which factors contribute to outcomes in these patients. The purpose of this study was to retrospectively analyze a cohort of patients submitted to MI-TLIF and to identify factors that can be associated with a worse postoperative outcome. Methods Clinical records from 283 patients were assessed and, according to Odom's criteria, postoperative clinical outcome at 12 months was classified as excellent, good, fair, and poor. Demographic variables, clinical data, and surgery-related data were analyzed, looking for associations between them and clinical outcome. A binomial logistic regression analysis was then performed to include those associations. Results The main variables associated with worse prognosis (“poor” class according to Odom's criteria) were a period of sick leave longer than 3 months before the surgery, age younger than 50 years, lytic spondylolisthesis, L5-S1 level, and occurrence of complications. These 5 conditions were included in a logistic regression analysis, and 3 of them were independently associated with poor outcome: operative complications, age younger than 50 years, and sick leave longer than 3 months before surgery. Conclusions Younger patients, those on a sick leave for more than 3 months before surgery, or those who suffered surgical complications tended to have less satisfactory results after MI-TLIF.

We thank the anonymous referee for a careful reading of the manuscript. DLH acknowledges financial support from the Science and Technology Facilities Council (STFC) via grant ST/M000877/1. MSC acknowledges the support by FCT/MCTES through the research grants UIDB/04434/2020, UIDP/04434/2020, and PTDC/FIS-AST/30389/2017, and by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (grant: POCI01-0145-FEDER-030389). MSC is supported by national funds through FCT in the form of a work contract. VA was supported by a research grant (00028173) fromVILLUMFONDEN. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant agreement no.: DNRF106). The research leading to these results has received funding from the Research Foundation Flanders (FWO) by means of a senior postdoctoral fellowship to DMB with grant agreement No. 1286521N. This project has been supported by the Lendulet Program of the Hungarian Academy of Sciences, project No. LP2018-7/2020 and by the EU's MW-Gaia COST Action (CA18104). ASG acknowledges financial support from the Max Planck Society under grant 'Preparations for PLATO science' and from ALMA-CONICYT under grant #31170029. ZsB acknowledges the support by the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences. LFM acknowledges the financial support from the UNAM under grant PAPIIT IN100918. CCL acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC). DM acknowledges the support of the National Astronomical Research Institute of Thailand (NARIT). JPG acknowledges funding support from Spanish public funds for research from project PID2019-107061GB-C63 from the 'Programas Estatales de Generacion de Conocimiento y Fortalecimiento Cientifico y Tecnologico del Sistema de I+D+i y de I+D+i Orientada a los Retos de la Sociedad', and from the State Agency for Research through the Center of Excellence Severo Ochoa' award to the Instituto de Astrof ' isica de Andaluc ' ia (SEV2017-0709), all from the Spanish Ministry of Science, Innovation and Universities (MCIU). TRY acknowledges support from the NSF REU program, grant number PHY-1359195. The material is based upon work supported by NASA under award number 80GSFC21M0002. AD was supported by the UNKP-20-5 New National Excellence Program of the Ministry of Human Capacities and the J ' anos Bolyai Research Scholarship of the Hungarian Academy of Sciences. AD would like to thank the City of Szombathely for support under Agreement No. 67.177-21/2016. AGH acknowledges support from 'FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento' under project E-FQM-041-UGR18 by Universidad de Granada and from Spanish public funds (including FEDER funds) for research under project ESP2017-87676-C5-2-R. ARB acknowledges funding support from Spanish public funds for research through the research grant PRE2018-084322, through projects ESP2017-87676-C5-5-R and PID2019-107061GB-C63, and from the State Agency for Research through the `Center of Excellence Severo Ochoa' award to the Instituto de Astrof ' isica de Andaluc ' ia (SEV-2017-0709), all from the Spanish Ministry of Science, Innovation and Universities (MCIU). We are grateful to Sowgata Chowdhury, supported by Polish NCN grant 2015/18/A/ST9/00578, for conducting some spectroscopic observations that are reported in this work. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by NASA's Science Mission directorate. Funding for the TESS Asteroseismic Science Operations Centre is provided by the Danish National Research Foundation (Grant agreement no.: DNRF106), ESA PRODEX (PEA 4000119301) and Stellar Astrophysics Centre (SAC) at Aarhus University. We thank the TESS team and staff and TASC/TASOC for their support of this work. This research has made use of the SIMBAD data base, operated at CDS, Strasbourg, France. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement., We present the results of a systematic search for new rapidly oscillating Ap (roAp) stars using the 2-min cadence data collected by the Transiting Exoplanet Survey Satellite (TESS) during its Cycle 1 observations. We identify 12 new roAp stars. Amongst these stars we discover the roAp star with the longest pulsation period, another with the shortest rotation period, and six with multiperiodic variability. In addition to these new roAp stars, we present an analysis of 44 known roAp stars observed by TESS during Cycle 1, providing the first high-precision and homogeneous sample of a significant fraction of the known roAp stars. The TESS observations have shown that almost 60 per cent (33) of our sample of stars are multiperiodic, providing excellent cases to test models of roAp pulsations, and from which the most rewarding asteroseismic results can be gleaned. We report four cases of the occurrence of rotationally split frequency multiplets that imply different mode geometries for the same degree modes in the same star. This provides a conundrum in applying the oblique pulsator model to the roAp stars. Finally, we report the discovery of non-linear mode interactions in α Cir (TIC 402546736, HD128898) around the harmonic of the principal mode – this is only the second case of such a phenomenon., UK Research & Innovation (UKRI), Science & Technology Facilities Council (STFC), Science and Technology Development Fund (STDF) ST/M000877/1, Portuguese Foundation for Science and Technology, European Commission UIDB/04434/2020 UIDP/04434/2020 PTDC/FIS-AST/30389/2017, FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao POCI-01-0145-FEDER-030389, European Commission, VILLUMFONDEN 00028173, Danmarks Grundforskningsfond DNRF106 FWO 1286521N, Lendulet Program of the Hungarian Academy of Sciences LP2018-7/2020, EU's MW-Gaia COST Action CA18104, Max Planck Society, Foundation CELLEX, ALMA-CONICYT 31170029, Hungarian Academy of Sciences, UNAM under grant PAPIIT IN100918, Natural Sciences and Engineering Research Council of Canada (NSERC), National Astronomical Research Institute of Thailand (NARIT), Spanish public funds the Spanish Ministry of Science, Innovation and Universities (MCIU) PID2019-107061GB-C63 PRE2018-084322 ESP2017-87676-C5-5-R, 'Programas Estatales de Generacion de Conocimiento y Fortalecimiento Cientifico y Tecnologico del Sistema de I+D+i y de I+D+i Orientada a los Retos de la Sociedad' from the Spanish Ministry of Science, Innovation and Universities (MCIU), State Agency for Research through the 'Center of Excellence Severo Ochoa' award from the Spanish Ministry of Science, Innovation and Universities (MCIU) SEV-2017-0709, National Science Foundation (NSF), NSF - Office of the Director (OD) PHY-1359195, National Aeronautics & Space Administration (NASA) 80GSFC21M0002, New National Excellence Program of the Ministry of Human Capacities UNKP-20-5, City of Szombathely 67.177-21/2016, 'FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento' by Universidad de Granada E-FQM-041-UGR18, Spanish public funds (FEDER) ESP2017-87676-C5-2-R, Polish NCN 2015/18/A/ST9/00578, NASA's Science Mission directorate, European Space Agency PEA 4000119301, Stellar Astrophysics Centre (SAC) at Aarhus University

The Transiting Exoplanet Survey Satellite (TESS) is recording short-cadence, high duty-cycle timeseries across most of the sky, which presents the opportunity to detect and study oscillations in interesting stars, in particular planet hosts. We have detected and analysed solar-like oscillations in the bright G4 subgiant HD 38529, which hosts an inner, roughly Jupiter-mass planet on a 14.3d orbit and an outer, low-mass brown dwarf on a 2136 d orbit. We combine results frommultiple stellarmodelling teams to produce robust asteroseismic estimates of the star's properties, including its mass M = 1.48 +/- 0.04 M-circle dot, radius R = 2.68 +/- 0.03 R-circle dot, and age t = 3.07 +/- 0.39 Gyr. Our results confirm that HD 38529 has a mass near the higher end of the range that can be found in the literature and also demonstrate that precise stellar properties can be measured given shorter timeseries than produced by CoRoT, Kepler, or K2., UK Science and Technology Facilities Council (STFC)UK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC) [ST/R0023297/1]; Danish National Research FoundationDanmarks Grundforskningsfond [DNRF106]; grant FPI-SO from the Spanish Ministry of Economy and Competitiveness (MINECO) [SEV-2015-0548-17-2, BES-2017-082610]; Spanish Ministry with the Ramon y Cajal fellowship [RYC-2015-17697]; NASANational Aeronautics & Space Administration (NASA) [NNX17AF27G, NNX16AI09G, 80NSSC19K0374]; TESS GI Program under NASA [80NSSC18K1585, 80NSSC19K0385]; Carlsberg FoundationCarlsberg Foundation [CF19-0649]; Independent Research Fund Denmark [7027-00096B]; Alexander von Humboldt Foundation at the Max-Planck-Institut fur Astrophysik; national funds through Fundacao para a Ciencia e Tecnologia (FCT); FCT/MCTES through national funds (PIDDAC) [UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/30389/2017]; Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE2020: Programa Operacional Competitividade e Internacionalizacao [POCI01-0145-FEDER-030389]; European Union's Horizon 2020 research and innovation programme under the H2020 Marie Sklodowska-Curie Actions grant [792848]; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TUBITAK:118F352]; NASA Explorer ProgramNational Aeronautics & Space Administration (NASA); PLATO-CNES grant, WHB, WJC, and MBN thank the UK Science and Technology Facilities Council (STFC) for support under grant ST/R0023297/1. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (grant DNRF106). LGC thanks the support from grant FPI-SO from the Spanish Ministry of Economy and Competitiveness (MINECO; research project SEV-2015-0548-17-2 and predoctoral contract BES-2017-082610). SM acknowledges support from the Spanish Ministry with the Ramon y Cajal fellowship number RYC-2015-17697. ARGS acknowledges the support from NASA under grant NNX17AF27G. RAG acknowledges the support of the PLATO-CNES grant. DLB acknowledges support from the TESS GI Program under NASA awards 80NSSC18K1585 and 80NSSC19K0385. JRM acknowledges support from the Carlsberg Foundation (grant CF19-0649). VSA acknowledges support from the Independent Research Fund Denmark (Research grant 7027-00096B). BN acknowledges postdoctoral funding from the Alexander von Humboldt Foundation taken at the Max-Planck-Institut fur Astrophysik. MSC and MD are supported in the form of work contracts funded by national funds through Fundacao para a Ciencia e Tecnologia (FCT). MSC and MD acknowledge support by FCT/MCTES through national funds (PIDDAC) by grants UIDB/04434/2020, UIDP/04434/2020, and PTDC/FIS-AST/30389/2017 and by Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE2020: Programa Operacional Competitividade e Internacionalizacao by grant POCI01-0145-FEDER-030389. TC acknowledges support from the European Union's Horizon 2020 research and innovation programme under the H2020 Marie Sklodowska-Curie Actions grant 792848 (PULSATION). SB acknowledges NASA grants NNX16AI09G and 80NSSC19K0374. ZCO, MY, and SO acknowledge the Scientific and Technological Research Council of Turkey (TUBITAK:118F352) This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by the NASA Explorer Program. Calculations in this paper had used the University of Birmingham's BlueBEAR High-Performance Computing service.1

The paper Variations of the mixing character of dipolar mixed modes in red giant stars was published inMNRAS 495, 621-636 (2020). There are a few corrections that we would like to make in this erratum. Firstly, in the original version of this manuscript, there was a typographical error in last author QS. Zhang s name. This has now been corrected as Q. S. Zhang. Secondly, we mislabelled the ordinate of Fig. (Figure Presented).

Measuring stellar inclinations is fundamental to understand planetary formation and dynamics as well as physical conditions during star formation. Oscillation spectra of red giant stars exhibit mixed modes that have both a gravity component from the radiative interior and a pressure component from the convective envelope. Gravity-dominated (g-m) mixed modes split by rotation are well separated inside frequency spectra, making possible accurate measurements of stellar inclinations. This work aims at developing an automated and general approach to measure stellar inclinations, that can be applied to any solar-type pulsator for which oscillation modes are identified, and at validating it using red giant branch stars observed by Kepler. We use the mean height-to-background ratio of dipole mixed modes with different azimuthal orders to measure stellar inclinations. The underlying statistical distribution of inclinations is recovered in an unbiased way using a probability density function for the stellar inclination angle. We derive stellar inclination measurements for 1139 stars on the red giant branch, for which Gehan et al. (2018) have identified the azimuthal order of dipole g-m mixed modes. Raw measured inclinations exhibit strong deviation with respect to isotropy which is expected for random inclinations over the sky. When taking uncertainties into account, the reconstructed distribution of inclinations actually follows the expected isotropic distribution of the rotational axis. This work highlights the biases that affect inclination measurements and provides the way to infer their underlying statistical distribution. When the star is seen either pole-on or equator-on, measurements are challenging and result in a biased distribution. Correcting biases that appear at the low- and high inclination regimes allows us to recover the underlying inclination distribution., Comment: 35 pages, accepted for publication in A&A

Thanks to the high quality data of space missions, the detection of mixed modes has become possible in numerous stars. In this work, we investigate how the mixing character of dipolar mixed modes changes with stellar evolution, as well as with frequency within each stellar model. This is achieved by monitoring the variations in the coupling strength and the period spacing of dipolar mixed modes in red-giant models. These parameters are measured by fitting the asymptotic expansion of mixed modes to the model frequencies of a grid of red-giant models with masses between 1.0 and 2.0 $M_\odot$ and three different chemical abundances. The coupling strength and the period spacing decrease with stellar evolution. We find that the slopes of their decreasing trends depend on the radial order of the pressure mode component. A non-negligible increase of the coupling strength with frequency by up to around 40\% is found in the observable frequency range for a set of red-giant models. On the contrary, no significant changes of the period spacing with frequency are found. The changes in the mixing character of the modes are in most cases affected by the model mass and metallicity. Buoyancy glitches also have an impact on the mixing character. Significant fluctuations in the estimated coupling strength and period spacing are found for models approaching the luminosity bump, if the glitch impact of the frequencies is not considered in the applied asymptotic expansion., Comment: 23 pages, 17 figures, 4 tables

Context. The variety of physical processes at play in chemically peculiar stars makes it difficult to determine their fundamental parameters. In particular, for the magnetic ones, called Ap stars, the strong magnetic fields and the induced spotted stellar surfaces may lead to biased effective temperatures when these values are derived through spectro-photometry. Aims. We propose to benefit from the exquisite angular resolution provided by long-baseline interferometry in the visible to determine the accurate angular diameters of a number of Ap stars, and thus estimate their radii by a method that is as independent as possible of atmospheric models. Methods. We used the visible spectrograph VEGA at the CHARA interferometric array to complete the sample of Ap stars currently observable with this technique. We estimated the angular diameter and radius of six new targets. We estimated their bolometric flux based solely on observational spectroscopic and photometric data to derive nearly model-independent luminosities and effective temperatures. Results. We extend to 14 the number of Ap stars for which interferometric angular diameters have been measured. The fundamental parameters we derived for the complete Ap sample are compared with those obtained through a self-consistent spectroscopic analysis. Based on a model fitting approach of high-resolution spectra and spectro-photometric observations over a wide wavelength range, this method takes into account the anomalous chemical composition of the atmospheres and the inhomogeneous vertical distribution for different chemical elements. Regarding both the radii and the effective temperatures, the derived values from our interferometric observations and from self-consistent modelling are consistent within better than 2σ for nine targets out of ten. We thus benchmark nine Ap stars for effective temperatures ranging from 7200 and 9100 K, and luminosities ranging between 7 L⊙ and 86 L⊙. Conclusions. These results will be key for the future derivation of accurate radii and other fundamental parameters of fainter peculiar stars for which both the sensitivity and the angular resolution of the current interferometers are not sufficient. Within the context of the observations of Ap stars with the Transiting Exoplanet Survey Satellite (TESS), these interferometric measurements are crucial for testing the mechanism of pulsation excitation at work in these peculiar stars. In particular, our interferometric measurements provide accurate locations in the Hertzsprung-Russell diagram for hot Ap stars among which pulsations may be searched for with TESS, putting to test the blue edge of the theoretical instability strip. These accurate locations could be used to derive masses and ages of these stars through a specific grid of models, and to test correlations between the properties of these peculiar stars and their evolutionary state.

We discuss and characterise the power spectral density properties of a model aimed at describing pulsations in stars from the main-sequence to the asymptotic giant branch. We show that the predicted limit of the power spectral density for a pulsation mode in the presence of stochastic noise is always well approximated by a Lorentzian function. While in stars predominantly stochastically driven the width of the Lorentzian is defined by the mode lifetime, in stars where the driving is predominately coherent the width is defined by the amplitude of the stochastic perturbations. In stars where both drivings are comparable, the width is defined by both these parameters and is smaller than that expected from pure stochastic driving. We illustrate our model through numerical simulations and propose a well defined classification of stars into predominantly stochastic (solar-like) and predominately coherent (classic) pulsators. We apply the model to the study of the Mira variable U Per, and the semiregular variable L2 Pup and, following our classification, conclude that they are both classical pulsators. Our model provides a natural explanation for the change in behaviour of the pulsation amplitude-period relation noted in several earlier works. Moreover, our study of L2 Pup enables us to test the scaling relation between the mode line width and effective temperature, confirming that an exponential scaling reproduces well the data all the way from the main sequence to the asymptotic giant branch, down to temperatures about 1000 K below what has been tested in previous studies., Comment: 11 pages, 8 figures, accepted for publication in MNRAS

The characterisation of stellar cores may be accomplished through the modelling of asteroseismic data from stars exhibiting either gravity-mode or mixed-mode pulsations, potentially shedding light on the physical processes responsible for the production, mixing, and segregation of chemical elements. In this work we validate against model data an analytical expression for the period spacing that will facilitate the inference of the properties of stellar cores, including the detection and characterisation of buoyancy glitches (strong chemical gradients). This asymptotically-based analytical expression is tested both in models with and without buoyancy glitches. It does not assume that glitches are small and, consequently, predicts non-sinusoidal glitch-induced period-spacing variations, as often seen in model and real data. We show that the glitch position and width inferred from the fitting of the analytical expression to model data consisting of pure gravity modes are in close agreement (typically better than 7$\%$ relative difference) with the properties measured directly from the stellar models. In the case of fitting mixed-mode model data, the same expression is shown to reproduce well the numerical results, when the glitch properties are known a priori. In addition, the fits performed to mixed-mode model data reveal a frequency dependence of the coupling coefficient, $q$, for a moderate-luminosity red-giant-branch model star. Finally, we find that fitting the analytical expression to the mixed-mode period spacings may provide a way to infer the frequencies of the pure acoustic dipole modes that would exist if no coupling took place between acoustic and gravity waves., Submitted to MNRAS

Background Patients' recall of their preoperative status is seldom used to assess surgical outcomes because of concerns about inaccuracy and bias. The present study aimed to measure the significance of this recall bias and its repercussion on patients' recollection of their preoperative status. Methods Patients submitted to surgery due to degenerative spine diseases over a 1-year period (n = 198) were included in this study. Each patient completed the EuroQol Five-Dimensional Questionnaire (including a visual analog scale), Core Outcome Measures Index (COMI) for neck (including neck pain and shoulder/arm pain numeric rating scale [NRS]), COMI back (including back pain and buttock/leg pain NRS), Neck Disability Index, and Oswestry Disability Index preoperatively. At 1 year after surgery, the patients were asked to complete 2 sets of the same questionnaires, one set regarding their postoperative status and the other set regarding their recall of their preoperative status. Results There was poor to moderate agreement between recalled and collected preoperative scores for all patient-reported outcome measures. Patients' recollection of their preoperative status was accurate for patients who underwent cervical spine surgery, but not for those who underwent lumbar spine surgery. Patients satisfied with the outcome after lumbar spine surgery recalled significantly worse scores compared with the actual preoperative scores. Conclusions Using patients' recall of their preoperative status may lead to overestimation of the effectiveness of surgery, particularly for lumbar spine surgery. The self-assessed effectiveness of surgery interferes with the recollection of baseline status.

Asteroseismic forward modelling techniques are being used to determine fundamental properties (e.g. mass, radius, and age) of solar-type stars. The need to take into account all possible sources of error is of paramount importance towards a robust determination of stellar properties. We present a study of 34 solar-type stars for which high signal-to-noise asteroseismic data is available from multi-year Kepler photometry. We explore the internal systematics on the stellar properties, that is, associated with the uncertainty in the input physics used to construct the stellar models. In particular, we explore the systematics arising from: (i) the inclusion of the diffusion of helium and heavy elements; and (ii) the uncertainty in solar metallicity mixture. We also assess the systematics arising from (iii) different surface correction methods used in optimisation/fitting procedures. The systematics arising from comparing results of models with and without diffusion are found to be 0.5%, 0.8%, 2.1%, and 16% in mean density, radius, mass, and age, respectively. The internal systematics in age are significantly larger than the statistical uncertainties. We find the internal systematics resulting from the uncertainty in solar metallicity mixture to be 0.7% in mean density, 0.5% in radius, 1.4% in mass, and 6.7% in age. The surface correction method by Sonoi et al. and Ball & Gizon's two-term correction produce the lowest internal systematics among the different correction methods, namely, ~1%, ~1%, ~2%, and ~8% in mean density, radius, mass, and age, respectively. Stellar masses obtained using the surface correction methods by Kjeldsen et al. and Ball & Gizon's one-term correction are systematically higher than those obtained using frequency ratios., 13 pages, 10 figures, 4 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society Journal

The properties of the acoustic modes are sensitive to magnetic activity. The unprecedented long-term Kepler photometry, thus, allows stellar magnetic cycles to be studied through asteroseismology. We search for signatures of magnetic cycles in the seismic data of Kepler solar-type stars. We find evidence for periodic variations in the acoustic properties of about half of the 87 analysed stars. In these proceedings, we highlight the results obtained for two such stars, namely KIC 8006161 and KIC 5184732., Comment: 4 pages, 1 figure, to appear in the Proceedings of the IAUS340

The equine influenza virus (EIV) H3N8 subtype is responsible for all EIV outbreaks worldwide while the H7N7 subtype is less pathogenic and is considered extinct as it has not been confirmed in outbreaks since 1980. Although EIV is enzootic in Brazil, few reports describe the actual EIV antibody status in the country. The aims of this study were: - to evaluate the efficiency of different serum treatments described by the World Organisation for Animal Health (OIE) and the World Health Organization (WHO) to remove non-specific haemagglutination inhibitors for the haemagglutination inhibition (HI) assay for EIV - to evaluate the presence of EIV antibodies by HI, enzyme-linked immunosorbent assay and agar gel immunodiffusion in 83 non-vaccinated equines from Sao Paulo State - to evaluate a strategy to better analyse equine sera for EIV antibodies. Although there was no statistical difference among treatments, receptor-destroying enzyme treatment followed by chicken erythrocyte adsorption showed more consistent results, which corroborate the OIE and WHO recommendation to use this treatment preferentially. The HI results suggest equine H3N8 virus circulation among the animals tested from Sao Paulo State. The algorithm suggested here could be used to guide antibody detection against equine influenza virus in equines, improving the test specificity by aiming to avoid false positive results.

We present the first results from the Transiting Exoplanet Survey Satellite (TESS) on the rotational and pulsational variability of magnetic chemically peculiar A-type stars. We analyse TESS 2-min cadence data from sectors 1 and 2 on a sample of 83 stars. Five new rapidly oscillating Ap (roAp) stars are announced. One of these pulsates with periods around 4.7 min, making it the shortest period roAp star known to date. Four out of the five new roAp stars are multiperiodic. Three of these and the singly periodic one show the presence of rotational mode splitting. Individual frequencies are provided in all cases. In addition, seven previously known roAp stars are analysed. Additional modes of oscillation are found in some stars, while in others we are able to distinguish the true pulsations from possible aliases present in the ground-based data. We find that the pulsation amplitude in the TESS filter is typically a factor of 6 smaller than that in the B filter, which is usually used for ground-based observations. For four roAp stars we set constraints on the inclination angle and magnetic obliquity, through the application of the oblique pulsator model. We also confirm the absence of roAp-type pulsations down to amplitude limits of 6 and 13 \mumag, respectively, in two of the best characterized non-oscillating Ap (noAp) stars. We announce 27 new rotational variables along with their rotation periods, and provide different rotation periods for seven other stars. Finally, we discuss how these results challenge state-of-the-art pulsation models for roAp stars.© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society., This work was supported by FCT - Fundacao para a Ciencia e a Tecnologia through national funds and by FEDER through COMPETE02020 - Programa Operacional Competitividade e Internacionalizacao by these grants: UID/FIS/04434/2019, PTDC/FIS-AST/30389/2017 & POCI-01-0145-FEDER-030389. MC is supported in the form of work contract funded by national funds through FCT. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant agreement no.: DNRF106). DLH and DWK acknowledge financial support from the Science and Technology Facilities Council (STFC) via grant ST/M000877/1. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. LFM acknowledges support from the UNAM by the way of DGAPA project PAPIIT IN100918. The research leading to these results has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No670519: MAMSIE) and from the Fonds Wetenschappelijk Onderzoek -Vlaanderen (FWO) under the grant agreement G0H5416N (ERC Opvangproject). MS acknowledges the financial support of Postdoc@MUNI project CZ.02.2.69/0.0/0.0/16 027/0008360. EN acknowledges the Polish National Science Center grants no. 2014/13/B/ST9/00902. JCS acknowledges funding support from Spanish public funds for research under projects ESP2017-87676-2-2 and ESP2015-65712-C5-5-R, and from project RYC-2012-09913 under the 'Ramon y Cajal' program of the Spanish Ministry of Science and Education. AGH acknowledges funding support from Spanish public funds for research under projects ESP2017-87676-2-2 and ESP2015-65712-C5-5-R of the Spanish Ministry of Science and Education. AS, ZsB, and RSz acknowledge the financial support of the GINOP-2.3.2-15-2016-00003, K-115709, K-113117, K-119517, and PD-123910 grants of the Hungarian National Research, Development and Innovation Office (NKFIH), and the Lendulet Program of the Hungarian Academy of Sciences, project No. LP2018-7/2018. GH has been supported by the Polish NCN grant 2015/18/A/ST9/00578. MLM acknowledges funding support from Spanish public funds for research under project ESP2015-65712-C5-3-R. JPG acknowledges funding support from Spanish public funds for research under project ESP2017-87676-C5-5-R. MLM and JPG also acknowledges funding support from the State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award for the Institute de Astrofisica de Andalucia (SEV-2017-0709). IS acknowledges funding support of NSF under projects DN 08-1/2016 and DN 18/13-12.12.2017. P. Kolaczek-Szymanski acknowledges support from the NCN grant no. 2016/21/B/ST9/01126. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program.

Late diagnosis of cervical bilateral facet dislocation is rare and contributes to concerns in the management of these patients. We present a case of a 44-year-old woman presented 8 months after a trauma with persistent neck pain, without neurological deficits. A bilateral C5-C6 facet dislocation was identified. The patient was treated with a combined C5-C6 approach: posterior facet joints release, anterior discectomy and fusion, bilateral posterior fixation. Surgery was performed under intraoperative neurophysiological monitoring. The postoperative period was uneventful, and the patient presented functional improvement. Late surgical treatment of bilateral cervical facet dislocation is safe and feasible. Combined procedures are needed for proper reduction and stabilization of the spine. Intraoperative neurophysiological monitoring adds value to this technique contributing to good outcomes.

We investigate the quantum evolution of the universe in the presence of two types of dark energies. First, we consider the phantom class ($\omega0$ vacuum ($\omega=-1$). This is done by analytically solving the Wheeler-DeWitt equation with ordering term (WdW) in the cosmology of Friedmann-Robertson-Walker. In this paper, we find exact solutions in the scale factor $a$ and the ordering parameter $q$. For $q=1$ it is shown that the universe has a high probability of evolving from a big bang singularity. On the other hand, for $q = 0$ the solution indicates that an initial singularity is unlikely. Instead, the universe has maximal probability of starting with a finite well-defined size which we compute explicitly at primordial times. We also study the time evolution of the scale factor by means of the Hamilton-Jacobi equation and show that an ultimate big rip singularity emerges explicitly from our solutions. The phantom scenario thus predicts a dramatic end in which the universe would reach an infinite scale factor in a finite cosmological time as pointed by Caldwell et al. in a classical setup. Finally, we solve the WdW equation with ordinary constant dark energy and show that in this case the universe does not rip apart in a finite era., Comment: 16 pages, improved figures, some new relevant conclusions, references added

In this work the wave functions associated to the quantum relativistic universe, which is described by the Wheeler-DeWitt equation, are obtained. Taking into account different kinds of energy density, namely, matter, radiation, vacuum, dark energy, and quintessence, we discuss some aspects of the quantum dynamics. In all these cases, the wave functions of the quantum relativistic universe are given in terms of the triconfluent Heun functions. We investigate the expansion of the universe using these solutions and found that the asymptotic behavior for the scale factor is $a(t) \sim \mbox{e}^{t}$ for whatever the form of energy density is. On the other hand, we analyze the behavior at early stages of the universe and found that $a(t) \sim t^{1/2}$. We also calculate and analyze the transmission coefficient through the effective potential barrier., Comment: 17 pages, 7 figures, 1 table

We present the analysis of K2 short cadence data of the rapidly oscillating Ap (roAp) star, 33 Librae (HD 137949). The precision afforded to the K2 data allow us to identify at least 11 pulsation modes in this star, compared to the three previously reported. Reoccurring separations between these modes leads us to suggest a large frequency separation, $\Delta\nu$, of 78.9 $\mu$Hz, twice that reported in the literature. Other frequency separations we detect may represent the small frequency separation, $\delta\nu$, but this is inconclusive at this stage due to magnetic perturbation of the frequencies. Due to the highly non-linear pulsation in 33 Lib, we identify harmonics to four times the principal frequency. Furthermore, we note a unique occurrence of non-linear interactions of the 11 identified modes. The frequency separations of the modes around the principal frequency are replicated around the first harmonic, with some interaction with the second harmonic also. Such a phenomenon has not been seen in roAp stars before. With revised stellar parameters, linear non-adiabatic modelling of 33 Lib shows that the pulsations are not greater than the acoustic cutoff frequency, and that the $\kappa$-mechanism can excite the observed modes. Our observations are consistent with 33 Lib having a rotation period much larger than 88 d as presented in the literature., Comment: 9 Pages, 9 Figures, 5 Tables. Accepted for publication in MNRAS

The equine influenza virus (EIV) H3N8 subtype is responsible for all EIV outbreaks worldwide while the H7N7 subtype is less pathogenic and is considered extinct as it has not been confirmed in outbreaks since 1980. Although EIV is enzootic in Brazil, few reports describe the actual EIV antibody status in the country. The aims of this study were: - to evaluate the efficiency of different serum treatments described by the World Organisation for Animal Health (OIE) and the World Health Organization (WHO) to remove non-specific haemagglutination inhibitors for the haemagglutination inhibition (HI) assay for EIV - to evaluate the presence of EIV antibodies by HI, enzyme-linked immunosorbent assay and agar gel immunodiffusion in 83 non-vaccinated equines from São Paulo State - to evaluate a strategy to better analyse equine sera for EIV antibodies. Although there was no statistical difference among treatments, receptor-destroying enzyme treatment followed by chicken erythrocyte adsorption showed more consistent results, which corroborate the OIE and WHO recommendation to use this treatment preferentially. The HI results suggest equine H3N8 virus circulation among the animals tested from São Paulo State. The algorithm suggested here could be used to guide antibody detection against equine influenza virus in equines, improving the test specificity by aiming to avoid false positive results.Tous les foyers de grippe équine dans le monde sont dus au sous-type H3N8 du virus. Le sous-type H7N7, moins pathogène, est considéré comme éteint, sa présence n’ayant été confirmée dans aucun des foyers enregistrés depuis 1980. Au Brésil, la grippe équine est enzootique mais la prévalence d’anticorps dans le pays est peu documentée. La présente étude avait trois objectifs : – évaluer l’efficacité de plusieurs traitements de sérums décrits par l’Organisation mondiale de la santé animale (OIE) et l’Organisation mondiale de la santé (OMS) sur la suppression des inhibiteurs d’hémagglutination non spécifiques, afin de pouvoir utiliser l’épreuve d’inhibition de l’hémagglutination pour la détection de la grippe équine, – évaluer la présence d’anticorps dirigés contre la grippe équine chez 83 chevaux non vaccinés de l’état de São Paulo en utilisant l’inhibition de l’hémagglutination, l’épreuve immuno-enzymatique (ELISA) et l’épreuve d’immunodiffusion en gélose (IDG) ; – évaluer une stratégie visant à améliorer les techniques sérologiques de détection des anticorps dirigés contre la grippe équine. S’il n’y a pas eu de différence statistique significative entre les traitements, celui faisant appel à l’enzyme de destruction du récepteur suivi d’une adsorption sur érythrocytes de poule a permis d’obtenir les résultats les plus cohérents, ce qui corrobore les recommandations de l’OIE et de l’OMS en faveur de ce traitement. Les résultats obtenus au moyen de l’inhibition de l’hémagglutination indiquent que le virus H3N8 est présent parmi les animaux testés de l’état de São Paulo. L’algorithme présenté par les auteurs pourrait servir de modèle pour détecter la présence d’anticorps dirigés contre le virus de la grippe équine chez les chevaux : en effet, il permet d’éviter les résultats faussement positifs, ce qui améliore la spécificité du test utilisé.El subtipo H3N8 del virus de la gripe equina (VGE) es el agente etiológico de todos los brotes que se producen en el mundo, mientras que el subtipo H7N7, menos patogénico, se da por extinto, en la medida en que desde 1980 no se ha confirmado su intervención en brote alguno. Aunque en el Brasil el VGE es enzoótico, existen pocos trabajos que den cuenta de la situación real del país en cuanto a la presencia de anticuerpos contra el virus. Los autores describen un estudio que perseguía los siguientes objetivos: – evaluar la eficacia de distintos tratamientos séricos descritos por la Organización Mundial de Sanidad Animal (OIE) y la Organización Mundial de la Salud (OMS) para eliminar los inhibidores inespecíficos de la hemaglutinación con objeto de aplicar la técnica de inhibición de la hemaglutinación a la detección del VGE; – evaluar la presencia de anticuerpos contra el VGE por inhibición de la hemaglutinación, ensayo inmunoenzimático (ELISA) e inmunodifusión en gel de agar en 83 ejemplares equinos no vacunados del estado de São Paulo; – evaluar una estrategia encaminada a analizar más eficazmente sueros equinos para detectar en ellos anticuerpos anti-VGE. Aunque no se observaron diferencias estadísticamente significativas entre los tratamientos, el uso de enzimas destructores de receptores seguido de la técnica de adsorción de eritrocitos de pollo arrojó resultados más coherentes, cosa que avala la recomendación de la OIE y la OMS de privilegiar este tratamiento. Los resultados obtenidos por inhibición de la hemaglutinación parecen indicar que el virus H3N8 equino circula entre los animales analizados del estado de São Paulo. El algoritmo aquí propuesto podría servir de guía para detectar en equinos la presencia de anticuerpos contra el VGE. Puesto que apunta a evitar falsos positivos, su aplicación mejoraría la especificidad de la prueba.

We use the exact analytical solution of the radial part of the Klein-Gordon equation describing a charged massive scalar field in the electrically charged Garfinkle-Horowitz-Strominger dilaton black hole spacetime, given in terms of the confluent Heun functions, to study the physical phenomena related to resonant frequencies associated to this field, and also to examine some aspects related to its Hawking radiation. The special case of a Schwarzschild spacetime is also considered., 30 pages, 10 figures

Context: the space-borne missions CoRoT and Kepler have provided photometric observations of unprecedented quality. The study of solar-like oscillations observed in red giant stars by these satellites allows a better understanding of the different physical processes occurring in their interiors. In particular, the study of the mode excitation and damping is a promising way to improve our understanding of stellar physics that has, so far, been performed only on a limited number of targets. Aims: the recent asteroseismic characterization of the evolutionary status for a large number of red giants allows us to study the physical processes acting in the interior of red giants and how they are modify during stellar evolution. In this work, we aim to obtain information on the excitation and damping of pressure modes through the measurement of the stars' pressure mode widths and amplitudes and to analyze how they are modified with stellar evolution. The objective is to bring observational constraints on the modeling of the physical processes behind mode excitation and damping. Methods: we fit the frequency spectra of red giants with well defined evolutionary status using Lorentzians functions to derive the pressure mode widths and amplitudes. To strengthen our conclusions, we used two different fitting techniques. Results: pressure mode widths and amplitudes were determined for more than 5000 red giants. With a stellar sample two orders of magnitude larger than previous results, we confirmed that the mode width depends on stellar evolution and varies with stellar effective temperature. In addition, we discovered that the mode width depends on stellar mass. We also confirmed observationally the influence of the stellar metallicity on the mode amplitudes, as predicted by models., 13 pages, 21 figures, 4 tables

The yellow fever virus (YFV) epidemic that began in Dec 2016 in Brazil is the largest in decades. The recent discovery of YFV in BrazilianAedes sp.vectors highlights the urgent need to monitor the risk of re-establishment of domestic YFV transmission in the Americas. We use a suite of epidemiological, spatial and genomic approaches to characterize YFV transmission. We show that the age- and sex-distribution of human cases in Brazil is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally using a new protocol reveals an early phase of sylvatic YFV transmission restricted to Minas Gerais, followed in late 2016 by a rise in viral spillover to humans, and the southwards spatial expansion of the epidemic towards previously YFV-free areas. Our results establish a framework for monitoring YFV transmission in real-time, contributing to the global strategy of eliminating future yellow fever epidemics.

BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has become a popular method of interbody fusion. Clinical outcomes after single-level MIS-TLIF have been reported, but few studies have focused on the radiologic changes in the segmental parameters of the operated and adjacent segments and in lumbar lordosis. METHODS: From March 2009 to September 2016, 117 patients who underwent a single-level MIS-TLIF surgery for lumbar degenerative disease were enrolled in this retrospective study. The anterior disc height (ADH), posterior disc height (PDH), and segmental angle (SA) of the operated and adjacent levels and lumbar lordosis (LL) were evaluated on radiographs obtained pre- and postoperatively at 6- to 12-month follow-up visits. Cage-related parameters including fusion and subsidence rates were analyzed on postoperative computed tomography scans. Clinical assessment used validated outcome scores such as the Oswestry Disability Index questionnaire and the Odom criteria. RESULTS: ADH and PDH of the operated segment increased significantly after surgery, but no significant changes were seen in the SA of that level. Statistically significant decreases were observed in the PDH of both adjacent segments and increases in the adjacent superior SA. LL showed a slight but statistically significant improvement after surgery that was mostly correlated with a postoperative increase in the adjacent superior SA (r = 0.58; P < 0.001). No significant correlations were found between clinical and radiologic results. CONCLUSIONS: Single-level MIS-TLIF increased disc height but not the SA at the operated level. LL improvement after surgery was mainly associated with the increase of the cranial segmental angle info:eu-repo/semantics/publishedVersion

Mixed modes have been extensively observed in post-main-sequence stars by the Kepler and CoRoT space missions. The mixture of the p and g modes can be measured by the dimensionless coefficient $q$, the so-called coupling strength factor. In this paper we discuss the utility of the phase shifts $\theta$ from the eigenvalue condition for mixed modes as a tool to characterize dipolar mixed modes from the theoretical as well as the practical point of view. Unlike the coupling strength, whose variation in a given star is very small over the relevant frequency range, the phase shifts vary significantly for different modes. The analysis in terms of $\theta$ can also provide a better understanding of the pressure and gravity radial order for a given mixed mode. Observed frequencies of the Kepler red-giant star KIC 3744043 are used to test the method. The results are very promising., Comment: 13 pages, 12 figures, 3 tables

This work aimed to verify the genetic variability of Fusarium oxysporum f. sp. cubense isolates based on aggressiveness and molecular data (ISSR, SSR and sequencing of the TEF-1α gene). A total of 152 isolates collected from banana-producing areas in the north and south regions of the state of Santa Catarina, Brazil, were compared. Isolates were collected from plants belonging to the Pome and Cavendish subgroups. Pathogenicity was confirmed for all isolates, and morphological traits confirmed the identity of the fungus. Greenhouse assays allowed classification of the isolates into three groups according to their aggressiveness. Results from ISSR, SSR and DNA sequencing revealed less variation since the majority of the isolates displayed 100 % similarity. Among the markers, ISSR and SSR were the most polymorphic in terms of differentiating with a larger percentage of dissimilarity. Results from aggressiveness tests indicated a tendency towards a consistent structure according to host or geographical origin of the isolates. No relationship between DNA markers and aggressiveness of isolates could be established.

The prevalence of antibodies against Equine Influenza Virus (EIV) was determined in 529 equines living on ranches in the municipality of Poconé, Pantanal area of Brazil, by means of the hemagglutination inhibition test, using subtype H3N8 as antigen. The distribution and possible association among positive animal and ranches were evaluated by the chi-square test, spatial autoregressive and multiple linear regression models. The prevalence of antibodies against EIV was estimated at 45.2% (95% CI 30.2 - 61.1%) with titers ranging from 20 to 1,280 HAU. Seropositive equines were found on 92.0% of the surveyed ranches. Equine from non-flooded ranches (66.5%) and negativity in equine infectious anemia virus (EIAV) (61.7%) were associated with antibodies against EIV. No spatial correlation was found among the ranches, but the ones located in non-flooded areas were associated with antibodies against EIV. A negative correlation was found between the prevalence of antibodies against EIV and the presence of EIAV positive animals on the ranches. The high prevalence of antibodies against EIV detected in this study suggests that the virus is circulating among the animals, and this statistical analysis indicates that the movement and aggregation of animals are factors associated to the transmission of the virus in the region. A prevalência de anticorpos para o vírus da Influenza Equina (VIE) no município de Poconé, MT. foi determinada em 529 equídeos pela técnica de Inibição da hemaglutinação utilizando como antígeno a variante H3N8 (SP/1/85). A distribuição da positividade e possíveis associações entre os animais e as propriedades foram avaliadas pelo teste do Qui-quadrado e pelos modelos espacial autoregressivo misto e de regressão linear múltipla. A prevalência de anticorpos para o VIE no município de Poconé foi estimada em 45,2% (IC 95% 30,2 - 61,1%) com títulos variando entre 20 e 1280UIH. Das fazendas analisadas 23 (92,0%) apresentaram animais soropositivos. Animais de fazendas não alagadas (66,5%) e negativos para Anemia Infecciosa Equina (AIE) (61,7%) foram associados a soropositividade. Não houve correlação espacial entre as fazendas estudadas, entretanto aquelas localizadas nas áreas não alagadas foram associadas à infecção. Observou-se correlação negativa entre a prevalência de anticorpos para o VIE e a presença de animais positivos para AIE nas propriedades. A elevada prevalência de anticorpos para o VIE detectada neste estudo sugere circulação viral ativa entre os animais, e as análises estatísticas indicam que o trânsito e aglomeração animal são fatores associados à transmissão do vírus na região.

Introducao e objetivos: O herpesvirus equino tipo 1 (EHV-1) e um patogeno de suma importância, responsavel por perdas significativas nos planteis, fato que, sob o ponto de vista economico, o torna uma ameaca potencial a criacao mundial de cavalos uma vez que a sua distribuicao e cosmopolita. Esse virus tem sido identificado como a causa de abortamentos, mortalidade neonatal, doenca respiratoria e manifestacoes neurologicas em cavalos [1,2]. Modelos experimentais de infeccao pelo EHV-1 utilizando roedores, como camundongos e hamsters, sao uteis para o estudo da resposta do hospedeiro ao virus, pois muitos dos aspectos da etiopatogenia da doenca nessas especies se assemelham aos observados no hospedeiro natural [3]. O camundongo e um excelente modelo para estudo da etiopatogenia da encefalite causada por estirpes neuropatogenicas do herpesvirus equino tipo 1 (EHV-1) [4]. No entanto, pesquisas recentes evidenciaram que a infeccao estabelecida pela via intranasal em hamsters resultou em sintomas mais agudos e severos do que nos camundongos, sugerindo uma maior susceptibilidade da especie ao agente [5,6]. Com base nesses dados, o presente trabalho foi delineado para avaliar as alteracoes respiratorias e neurologicas decorrentes da infeccao pelo EHV-1 em hamsters, comparando a susceptibilidade desse modelo com estudos realizados em camundongos e equinos. Materiais e metodos: Hamsters Sirios machos, com tres semanas de idade, foram infectados pela via intranasal com estirpes do EHV-1, obtidas de fetos abortados e potros infectados pelo virus (A4/72, A9/92, A3/97 e ISO/72). Os hamsters foram pesados e examinados diariamente observando-se o aparecimento de manifestacoes neurologicas e/ou respiratorias da doenca. De acordo com o aparecimento dos sintomas, grupos de cinco hamsters foram submetidos a eutanasia por overdose de isoflurano e deles foram coletados os materiais: SNC, pulmoes, timo, figado e baco que foram encaminhados tanto para a realizacao de isolamento viral em cultura de celulas E-dermal como para exame histopatologico. Em uma segunda etapa que tambem utilizou cinco hamsters por grupo, inoculados com as mesmas estirpes virais, apos eutanasia por aplicacao intraperitoneal de overdose de cetamina e xilazina, foi realizada para a obtencao do lavado bronco-alveolar (LBA). Foi determinada a contagem total e diferencial de globulos brancos a partir do LBA dos hamsters. Resultados e discussao: De forma similar aos experimentos realizados com camundongos, os hamsters desafiados com as estirpes A4/72 e A9/92 apresentaram manifestacoes clinicas severas no 3o dia pos-inoculacao (dpi) tais como a perda de peso representada no grafico 1, apatia, dispneia, desidratacao, decubito e morte. Tambem foram observados sinais neurologicos como hiperexcitabilidade, paralisia espastica, perda de propriocepcao, andar em circulos e convulsoes. Ao contrario do modelo murino, em que nao foi desenvolvida a doenca, os hamsters inoculados com as estirpes A3/97 e ISO/72 apresentaram sintomas clinicos e neurologicos no 4o dpi, onde as alteracoes respiratorias foram as mais evidentes, com destaque para a epistaxe. O isolamento do virus do SNC foi positivo em todos os animais; no entanto, os pulmoes foram positivos apenas nos grupos infectados pelas estirpes A9/92 e A4/72. Nos demais orgaos houve variacao de resultado entre os grupos como visualizado na tabela 1. O LBA mostrou que a contagem total de leucocitos apresentou maior numero de celulas brancas nos hamsters infectados por A4/72 quando comparado com A9/92, A3/97 e ISO/72 e grupo controle. Entretanto, o aumento de leucocitos total encontrado nos grupos de hamsters inoculados nao foi significativo (p>0,05) quando comparado ao valor de leucocitos total do grupo controle. Macrofagos ativados com citoplasma bastante vacuolizado, alguns deles contendo grânulos intracitoplasmaticos e uma grande quantidade de eritrocitos foi observada em esfregacos da maioria dos animais inoculados ao contrario dos esfregacos do grupo controle, que em sua maior parte apresentou apenas celulas macrofagicas de citoplasma vacuolizado e raros eritrocitos. Os valores apresentados na tabela 2 revelam que a contagem total e diferencial de leucocitos variou tanto entre as estirpes como tambem entre os individuos de um mesmo grupo. De modo semelhante ao descrito em cavalos em experimentos de inoculacao com EHV-1 [7], na contagem diferencial no LBA notou-se nos hamsters infectados apresentaram um aumento no numero de neutrofilos acompanhado de um decrescimo de macrofagos, enquanto no grupo controle a celula predominante foi o macrofago variando de 90 a 100% da contagem total dos leucocitos como observado na tabela 2. Os grupos de hamsters infectados por A3/97 e A4/72 apresentaram um aumento significativo (p 0,05) de neutrofilos e uma diminuicao nao significativa de macrofagos. A diferenca encontrada nos numeros de linfocitos e monocitos entre os grupos inoculados e o grupo controle nao foi significativa. Conclusao: Os sintomas e os sinais clinicos observados durante o experimento indicaram que o hamster e a especie mais susceptivel frente a infeccao causada pelo EHV-1, quando comparada ao modelo murino. Alem disso, notou-se que a resposta dos macrofagos alveolares do hamster frente a infeccao pelo EHV-1 foi similar a do equino, o que torna a especie um atrativo modelo experimental para posteriores estudos com o agente viral.

Background: An outbreak of measles was reported in Timor-Leste during 2011. A concerted response at national level utilized this opportunity to improve measles immunization coverage rates. Methods: Health Management Information System and Surveillance System data were utilized to describe the outbreak. Attack rates and case fatality rates (CFR) were calculated using standard methods. Evaluation surveys were used to access immunization coverage. Proceedings of weekly meetings of the National Committee for Control of Disease Outbreaks were reviewed. Results: A total of 739 cases and 8 deaths were reported to the Surveillance Unit. Most (>82%) of the measles cases were reported from Dili and Ermera districts. The attack rate was 1.3 per 1000 population and CFR was 1.1%. The response was coordinated by the National Committee for Control of Disease Outbreaks, which included case management, active and passive surveillance, communication and measles immunization among six-month to 14-year old children. Immunization activity targeted 495 000 children, i.e. almost one-half of the Timor-Leste population and achieved high coverage (85%). Conclusions: The outbreak highlighted gaps in the immunity against measles. The National Committee for Control of Disease Outbreaks ensured a coordinated response which led to prevention of deaths from measles due to early case management with vitamin A supplementation, and high measles immunization coverage.

Banana is one of the most popular fruits in the world but has been substantially impaired by Panama disease in the last years. Fusarium oxysporum f. sp. cubense (Foc) is the causal agent and colonizes banana cultivars from many subgroups with different aggressiveness levels, often leading to plant death while compromising new crops in infested areas. This study has evaluated the ability of MALDI-MS protein and lipid fingerprinting to provide intraspecies classification of Foc isolates and to screen biomolecules related to host-pathogen relationship. The MS data, when inspected via partial least square discriminant analysis (PLS-DA), distinguished the isolates by aggressiveness as well as by specific location and host. Although both lipids and proteins show discriminating tendencies, these differences were more clearly perceived via the protein profiles. Considering that Cavendish cultivar is the more resistant option to endure Foc presence in the field, the lipids and proteins related to this subgroup might have an important role in pathogen adaptation. This study reports a new application of MALDI-MS for the analysis of a banana pathogen with intraspecies classification ability. Graphical abstract MALDI-MS classified Foc isolates by aggressiveness level on banana revealing the additional influence of location and host cultivar on the expression of lipids and proteins.

We report 12 cases of aggressive natural killer (NK) cell neoplasms diagnosed in Portugal, with emphasis on flow cytometry. Ten patients had extranodal NK/T cell lymphoma, nasal type and two had aggressive NK cell leukemia, and seven were men and five were women, with a median age of 50 years. NK cells brightly expressed the CD56 adhesion molecule and CD94 lectin type killer receptor and had an activation-related HLA-DR+ CD45RA+ CD45RO+ immunophenotype, in most cases. In contrast, dim CD16 expression was found in a minor proportion of cases, whereas CD57 and the CD158a and CD158e1 killer immunoglobulin-like receptors were negative. One-third of cases showed a hyperploid DNA content and nearly all had a very high S-phase proliferative rate. The phenotypic features of the neoplastic NK cells would suggest that they represent the transformed counterpart of the CD56 + bright NK cells that circulate in normal blood.

Aims.The aim of this work is to search for planets around intermediate-mass stars in open clusters using data from an extensive survey with more than 15 yr of observations.Methods.We obtain high-precision radial velocities (RV) with the HARPS spectrograph for a sample of 142 giant stars in 17 open clusters. We fit Keplerian orbits when a significant periodic signal is detected. We also study the variation of stellar activity indicators and line-profile variations to discard stellar-induced signals.Results.We present the discovery of a periodic RV signal compatible with the presence of a planet candidate in the 1.15 Gyr open cluster IC 4651 orbiting the 2.06M⊙star No. 9122. If confirmed, the planet candidate would have a minimum mass of 7.2MJand a period of 747 days. However, we also find that the full width at half maximum (FWHM) of the cross-correlation function (CCF) varies with a period close to the RV, casting doubts on the planetary nature of the signal. We also provide refined parameters for the previously discovered planet around NGC 2423 No. 3, but show evidence that the bisector inverse slope (BIS) of the CCF is correlated with the RV during some of the observing periods. We consider this fact as a warning that this might not be a real planet and that the RV variations could be caused by stellar activity and/or pulsations. Finally, we show that the previously reported signal by a brown dwarf around NGC 4349 No. 127 is presumably produced by stellar activity modulation.Conclusions.The long-term monitoring of several red giants in open clusters has allowed us to find periodic RV variations in several stars. However, we also show that the follow-up of this kind of stars should last more than one orbital period to detect long-term signals of stellar origin. This work highlights the fact that although it is possible to detect planets around red giants, large-amplitude, long-period RV modulations do exist in such stars that can mimic the presence of an orbiting planetary body. Therefore, we need to better understand how such RV modulations behave as stars evolve along the red giant branch and perform a detailed study of all the possible stellar-induced signals (e.g., spots, pulsations, granulation) to comprehend the origin of RV variations.

Our poor understanding of the boundaries of convective cores generates large uncertainties on the extent of these cores and thus on stellar ages. Our aim is to use asteroseismology to consistently measure the extent of convective cores in a sample of main-sequence stars whose masses lie around the mass-limit for having a convective core. We first test and validate a seismic diagnostic that was proposed to probe in a model-dependent way the extent of convective cores using the so-called $r_{010}$ ratios, which are built with $l=0$ and $l=1$ modes. We apply this procedure to 24 low-mass stars chosen among Kepler targets to optimize the efficiency of this diagnostic. For this purpose, we compute grids of stellar models with both the CESAM2k and MESA evolution codes, where the extensions of convective cores are modeled either by an instantaneous mixing or as a diffusion process. Among the selected targets, we are able to unambiguously detect convective cores in eight stars and we obtain seismic measurements of the extent of the mixed core in these targets with a good agreement between the CESAM2k and MESA codes. By performing optimizations using the Levenberg-Marquardt algorithm, we then obtain estimates of the amount of extra-mixing beyond the core that is required in CESAM2k to reproduce seismic observations for these eight stars and we show that this can be used to propose a calibration of this quantity. This calibration depends on the prescription chosen for the extra-mixing, but we find that it should be valid also for the code MESA, provided the same prescription is used. This study constitutes a first step towards the calibration of the extension of convective cores in low-mass stars, which will help reduce the uncertainties on the ages of these stars., 27 pages, 15 figures, accepted in A&A