Evidence for a physically bound third component in HD 150136

Context. HD150136 is one of the nearest systems harbouring an O3 star. Although this system was for a long time considered as binary, more recent investigations have suggested the possible existence of a third component. Aims. We present a detailed analysis of HD 150136 to confirm the triple nature of this system. In addition, we investigate the physical properties of the individual components of this system. Methods. We analysed high-resolution, high signal-to-noise data collected through multi-epoch runs spread over ten years. We applied a disentangling program to refine the radial velocities and to obtain the individual spectra of each star. With the radial velocities, we computed the orbital solution of the inner system, and we describe the main properties of the orbit of the outer star such as the preliminary mass ratio, the eccentricity, and the orbital-period range. With the individual spectra, we determined the stellar parameters of each star by means of the CMFGEN atmosphere code. Results. We offer clear evidence that HD 150136 is a triple system composed of an O3V((f\ast))-3.5V((f+)), an O5.5-6V((f)), and an O6.5-7V((f)) star. The three stars are between 0-3 Myr old. We derive dynamical masses of about 64, 40, and 35 Msun for the primary, the secondary and the third components by assuming an inclination of 49{\deg}. It currently corresponds to one of the most massive systems in our galaxy. The third star moves with a period in the range of 2950 to 5500 d on an outer orbit with an eccentricity of at least 0.3. This discovery makes HD 150136 the first confirmed triple system with an O3 primary star. However, because of the long orbital period, our dataset is not sufficient to constrain the orbital solution of the tertiary component with high accuracy.Comment: 13 pages, 11 figures, accepted at A&

Rickettsia parkeri in Amblyomma triste from Uruguay

Our goal was to detect whether spotted fever group Rickettsia are found in the suspected vector of rickettsioses, Amblyomma triste, in Uruguay. Rickettsia parkeri was detected in A. triste, which suggests that this species could be considered a pathogenic agent responsible for human rickettsioses in Uruguay

Fast carbon turnover after logging in the Semi-Arid Chaco forest (Argentina)

Fil: Kowaljow, Esteban. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, Georgina. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Pérez Harguindeguy, Natalia. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, Sandra. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Although the effect of forest logging on soil organic C (SOC) has been studied across different ecosystems, there is no consensus on the general resulting pattern, showing increases, decreases or not net changes in comparison with the former forest. A reduction on SOC content is expected as a result of disturbance activities promoting C loss or removal from the surface organic matter. Increased litter inputs resulting from a higher net primary productivity of young stands relative to mature stands could also being expected, increasing the SOC content of the logged sites, coupled with the deeper effect of an increased decomposition of dead roots from the removed woody biomass. A balance between these factors could also be resulting in no net C change on soils after logging. We aim to test the change on SOC up to 2 m depth in the semiarid Chaco of Central Argentina where an increased selective logging as result of extended silvopastoral activities is increasingly common. Using a paired sampling design we aim to compare the effect of selective logging of four different ages (3, 7, 9 & 22 years after logged, n=4) over the SOC content through the soil profile up to 2 m depth. SOC between forests have shown no significant differences indicating the homogeneity in climatic and soil variables under the study area. SOC under selective logging showed significant differences between them and with the correspondent former forest not only at surface but also at depth. SOC content had significantly increased after 22 years of forest logging showing a similar pattern that the model proposed by Covington and others, although the results showed on this study need to be replicated including selective logging on a broader range of times since logging has taken place. Our results seems to indicate a net decrease in SOC during the first years after disturbance (1.64 kg m-2 to a 2 m depth) followed by an increase during the following 22 years in the SOC content reaching a maximum of a net increase of 4.65 kg m-2 to a 2 m depth after 22 years of disturbance. A better understanding of the direction and magnitude of these changes is important for predicting the effect of land use change on soil fertility at regional level as well as its consequences for the global C cycle.https://scisoc.confex.com/scisoc/2014SES/webprogram/Person510967.htmlFil: Kowaljow, Esteban. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, Georgina. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Pérez Harguindeguy, Natalia. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, Sandra. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Ecologí

The Struve-Sahade effect in the optical spectra of O-type binaries I. Main-sequence systems

We present a spectroscopic analysis of four massive binary systems that are known or are good candidates to display the Struve-Sahade effect (defined as the apparent strengthening of the secondary spectrum of the binary when the star is approaching, and the corresponding weakening of the lines when it is receding). We use high resolution optical spectra to determine new orbital solutions and spectral types of HD 165052, HD 100213, HD 159176 and DH Cep. As good knowledge of the fundamental parameters of the considered systems is necessary to examine the Struve-Sahade effect. We then study equivalent width variations in the lines of both components of these binaries during their orbital cycle. In the case of these four systems, variations appear in the equivalent widths of some lines during the orbital cycle, but the definition given above can any longer be valid, since it is now clear that the effect modifies the primary spectrum as much as the secondary spectrum. Furthermore, the lines affected, and the way in which they are affected, depend on the considered system. For at least two of them (HD 100213 and HD 159176) these variations probably reflect the ellipsoidal variable nature of the system.Comment: 12 pages, 20 figures, in press A&

A comprehensive study of reported high metallicity giant HII regions. I. Detailed abundance analysis

We present long-slit observations in the optical and near infrared of fourteen HII regions in the spiral galaxies: NGC 628, NGC 925, NGC 1232 and NGC 1637, all of them reported to have solar or oversolar abundances according to empirical calibrations. For seven of the observed regions, ion-weighted temperatures from optical forbidden auroral to nebular line ratios have been obtained and for six of them, the oxygen abundances derived by standard methods turn out to be significantly lower than solar. The other one, named CDT1 in NGC 1232, shows an oxygen abundance of 12+log(O/H) = 8.95+-0.20 and constitutes, to the best of our knowledge, the first high metallicity HII region for which accurate line temperatures, and hence elemental abundances, have been derived. For the rest of the regions no line temperature measurements could be made and the metallicity has been determined by means of both detailed photoionisation modelling and the sulphur abundance parameter S_23. Only one of these regions shows values of O_23 and S_23 implying a solar or oversolar metallicity. According to our analysis, only two of the observed regions can therefore be considered as of high metallicity. The two of them fit the trends previously found in other high metallicity HII regions, i.e. N/O and S/O abundance ratios seem to be higher and lower than solar respectively.Comment: Accepted for publication by MNRA

Soil carbon dynamic associated to land-use changes in semi-arid forests of Argentina

Fil: Conti, G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Baptist, F. Biotope; Francia.Fil: Rumpel, C. Centre national de la recherche scientifique; Francia.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Land-use change represents one of the main drivers of global climatic change, affecting the amount and quality of organic matter (OM) in soils worldwide. A reduction in the amount of biomass due to forest management is expected to affect both the amount of new OM going into the soil and its microbial decomposability due to changes in soil environmental conditions. These changes should impact soil microbial communities, their activity and decomposition rates, affecting the amount and quality of organic carbon (OC) remaining in the soil. In order to obtain information on the effect of land-use change on the OM quantity and quality, its origin and its degree of stabilization (i.e., microbial decomposability), we characterized the amount of OC, the lignin and polysaccharide compounds by wet chemical analysis, as well as basal respiration rates across a disturbance gradient (n=20) in a semiarid Chaco forest of central Argentina. Disturbance reduced the amount and quality of litterfall, reflected in a reduction in SOM content. Soil carbohydrates content followed the same trend but lignin was not affected by land-use change. Although basal CO2 effluxes showed the same pattern than SOM content, when normalized per OC content, they showed the opposite trend, with higher CO2 released per C in sites with lower OC and carbohydrates content. Our results support the idea that in the semi-arid Chaco forest, chemically labile compounds are more vulnerable to disturbance, but also that OM could be protected and stabilized regardless of its chemical identity.Fil: Conti, G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Baptist, F. Biotope; Francia.Fil: Rumpel, C. Centre national de la recherche scientifique; Francia.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Ecologí

Early-type stars in the young open cluster NGC 2244 and in the Mon OB2 association I. The multiplicity of O-type stars

Aims. We present the results obtained from a long-term spectroscopic campaign devoted to the multiplicity of O-type stars in the young open cluster NGC2244 and in the Mon OB2 association. Methods. Our spectroscopic monitoring was performed over several years, allowing us to probe different time-scales. For each star, several spectral diagnostic tools are applied, in order to search for line shifts and profile variations. We also measure the projected rotational velocity and revisit the spectral classification. Results. In our sample, several stars were previously considered as spectroscopic binaries, though only a few scattered observations were available. Our results now reveal a more complex situation. Our study identifies two new spectroscopic binaries (HD46149 in NGC2244 and HD46573 in MonOB2). The first object is a long-period double-lined spectroscopic binary, though the exact value of its period remains uncertain and the second object is classified as an SB1 system with a period of about 10.67 days but the time series of our observations do not enable us to derive a unique orbital solution for this system. We also classify another star as variable in radial velocity (HD46150) and we detect line profile variations in two rapid rotators (HD46056 and HD46485). Conclusions. This spectroscopic investigation places a firm lower limit (17%) on the binary fraction of O-stars in NGC2244 and reveals the lack of short-period O+OB systems in this cluster. In addition, a comparison of these new results with two other well-studied clusters (NGC6231 and IC1805) puts forward possible hints of a relation between stellar density and binarity, which could provide constraints on the theories about the formation and early evolution of hot stars.Comment: 14 pages, 10 figures, 9 table

Exploración pedagógica en el campo de la performance musical a partir del empleo de un juego didáctico: Persona Sobre el Escenario

En este artículo se describe un juego didáctico con valor proyectivo: Persona Sobre el Escenario (PSE-JD), un instrumento destinado a poner de manifiesto el modo en que se posiciona cada performer al realizar su autoevaluación y los conflictos internos que surjen a partir de ello. Se realizó una prueba del juego en la que participaron 48 estudiantes y docentes del Conservatorio Superior de Música Astor Piazzolla de la Ciudad Autónoma de Buenos Aires. El uso del PSE-JD permitió caracterizar tres aspectos principales. En primer lugar, el posicionamiento empleado por cada estudiante: la mayoría adopta modalidades de tipo confrontativo, reactivo, dependiente o abandonante. En segundo lugar, el tipo de paridad o disparidad en relación con el poder que se le atribuye a la autoevaluación: aproximadamente dos de cada tres estudiantes mostraron relaciones asimétricas en las que su autoevaluación domina al performer. Y, en tercer lugar, la manera en que el performer reacciona ante la autoevaluación: la mayor parte adopta una postura de sumisión. Además de permitir una caracterización empírica de la actitud que cada performer emplea al autoevaluarse, el PSE-JD posibilita un análisis profundo de las relaciones de poder que se instalan durante el aprendizaje y permite el estudio del surgimiento de la Ansiedad por Performance Musical. Se muestra, por lo tanto, como una herramienta útil para ser aplicada en el campo pedagógico como moderadora de los procesos de enseñanza, aprendizaje y evaluación.This work is aimed to describe a novel didactic game with projective utility: Person on Stage (PSE-JD). The instrument was designed to reveal the attitude adopted by a performer while self-assessing, and the internal conflicts arising from it. Forty-eight students and teachers from the Conservatorio Superior de Música Astor Piazzolla of Buenos Aires participated in a game test. The use of PSE-JD allowed us to characterize three main aspects. First, the self-assessment attitude: participants mostly used confrontational, reactive, dependent or abandoning modalities. Second, the level of parity or disparity in relation to the power given to the self-evaluation: about two thirds exhibited asymmetric relationship where the performer is dominated by the self-assessment. And third, the reaction of the performer against the self-evaluation: most of the participants exhibited a submission attitude. Besides allowing an empirical characterization of the self-assessment modality, the PSE-JD enables a deep analysis of authoritative relations installed during learning and allows the study of the emergence of Music Performance Anxiety. It appears as a useful tool to be applied in the pedagogical field for regulating teaching, learning and evaluation processes.Sociedad Argentina para las Ciencias Cognitivas de la Músic

Exploración pedagógica en el campo de la performance musical a partir del empleo de un juego didáctico: Persona Sobre el Escenario

En este artículo se describe un juego didáctico con valor proyectivo: Persona Sobre el Escenario (PSE-JD), un instrumento destinado a poner de manifiesto el modo en que se posiciona cada performer al realizar su autoevaluación y los conflictos internos que surjen a partir de ello. Se realizó una prueba del juego en la que participaron 48 estudiantes y docentes del Conservatorio Superior de Música Astor Piazzolla de la Ciudad Autónoma de Buenos Aires. El uso del PSE-JD permitió caracterizar tres aspectos principales. En primer lugar, el posicionamiento empleado por cada estudiante: la mayoría adopta modalidades de tipo confrontativo, reactivo, dependiente o abandonante. En segundo lugar, el tipo de paridad o disparidad en relación con el poder que se le atribuye a la autoevaluación: aproximadamente dos de cada tres estudiantes mostraron relaciones asimétricas en las que su autoevaluación domina al performer. Y, en tercer lugar, la manera en que el performer reacciona ante la autoevaluación: la mayor parte adopta una postura de sumisión. Además de permitir una caracterización empírica de la actitud que cada performer emplea al autoevaluarse, el PSE-JD posibilita un análisis profundo de las relaciones de poder que se instalan durante el aprendizaje y permite el estudio del surgimiento de la Ansiedad por Performance Musical. Se muestra, por lo tanto, como una herramienta útil para ser aplicada en el campo pedagógico como moderadora de los procesos de enseñanza, aprendizaje y evaluación.This work is aimed to describe a novel didactic game with projective utility: Person on Stage (PSE-JD). The instrument was designed to reveal the attitude adopted by a performer while self-assessing, and the internal conflicts arising from it. Forty-eight students and teachers from the Conservatorio Superior de Música Astor Piazzolla of Buenos Aires participated in a game test. The use of PSE-JD allowed us to characterize three main aspects. First, the self-assessment attitude: participants mostly used confrontational, reactive, dependent or abandoning modalities. Second, the level of parity or disparity in relation to the power given to the self-evaluation: about two thirds exhibited asymmetric relationship where the performer is dominated by the self-assessment. And third, the reaction of the performer against the self-evaluation: most of the participants exhibited a submission attitude. Besides allowing an empirical characterization of the self-assessment modality, the PSE-JD enables a deep analysis of authoritative relations installed during learning and allows the study of the emergence of Music Performance Anxiety. It appears as a useful tool to be applied in the pedagogical field for regulating teaching, learning and evaluation processes.Sociedad Argentina para las Ciencias Cognitivas de la Músic

La autoevaluación como destreza en el músico performer

La performance musical implica en todas sus instancias la recepción de una evaluación respecto del desempeño desplegado en la misma. Algunas intervenciones pedagógicas normalizadas en la formación tradicional tienden a propiciar niveles de alerta excesivos para un óptimo desempeño, ocasionando la merma en las capacidades de asimilación de conocimientos y praxis musicales que se podrá en evidencia durante la performance, además incrementando el riesgo de lesiones. En función de interrogar esta problemática hemos diseñado un autorreporte aplicado en setecientos ochenta músicos de Argentina, recogiendo indicadores de niveles excesivos de alerta. Considerando que niveles intermedios de alerta resultan ser los que se corresponden con un estado de activación óptimo para la tarea del performer, nos hemos propuesto precisar aquellas intervenciones capaces de favorecer la disposición de aprendizaje en los alumnos, minimizando la subjetividad en el campo de los procedimientos pedagógicos. La matriz evaluativa presente en clase resulta incorporada por el alumno transformándose en parte de su repertorio comportamental. La autoevaluación se constituye como una destreza capaz de brindar autonomía en el estudio, moderación del alerta y la posibilidad de efectuar correcciones eficientes incluso en tiempo real durante la interpretación musical. &nbsp