1,163 research outputs found

    The planetary nebula IC 4776 and its post-common-envelope binary central star

    Get PDF
    We present a detailed analysis of IC 4776, a planetary nebula displaying a morphology believed to be typical of central star binarity. The nebula is shown to comprise a compact hourglass-shaped central region and a pair of precessing jet-like structures. Time-resolved spectroscopy of its central star reveals periodic radial velocity variability consistent with a binary system. While the data are insufficient to accurately determine the parameters of the binary, the most likely solutions indicate that the secondary is probably a low-mass main sequence star. An empirical analysis of the chemical abundances in IC 4776 indicates that the common-envelope phase may have cut short the AGB evolution of the progenitor. Abundances calculated from recombination lines are found to be discrepant by a factor of approximately two relative to those calculated using collisionally excited lines, suggesting a possible correlation between low abundance discrepancy factors and intermediate-period post-common-envelope central stars and/or Wolf-Rayet central stars. The detection of a radial velocity variability associated with binarity in the central star of IC 4776 may be indicative of a significant population of (intermediate-period) post-common-envelope binary central stars which would be undetected by classic photometric monitoring techniques.Comment: Accepted for publication in MNRA

    Examining the joint effects of strategic priorities, use of management control systems, and personal background on hospital performance

    Get PDF
    This study aims to respond to recent calls for a better understanding of the factors that support the effectiveness of formal control practices in hospitals. Based on survey data from 117 top-level managers in Belgian hospitals, the study investigates the performance effects of the alignment between the use of performance measurement systems (PMS), strategic priorities, and the particular role top-level managers’ personal background plays in this context. The quantitative results suggest that it is the top-level managers’ personal background that brings to life the benefits of the alignment between the use of PMS and strategic priorities in hospitals. Specifically, this paper shows that when the emphasis on partnership or governance strategic priority is high, the effect of the interactive use of PMS on hospital performance is more positive for top-level managers with a clinical background than for those with an administrative background. This study offers value for practitioners in that it supports the argument that hospitals can benefit from involving physicians in the top-level management team

    The GRAVITY+ Project: Towards All-sky, Faint-Science, High-Contrast Near-Infrared Interferometry at the VLTI

    Full text link
    The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well as faint-science and high-contrast capabilities. This upgrade includes the implementation of wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, and laser guide stars in an upgraded facility. GRAVITY+ will open up the sky to the measurement of black hole masses across cosmic time in hundreds of active galactic nuclei, use the faint stars in the Galactic centre to probe General Relativity, and enable the characterisation of dozens of young exoplanets to study their formation, bearing the promise of another scientific revolution to come at the VLTI.Comment: Published in the ESO Messenge

    Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

    Get PDF
    Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio

    Avances en Informática y Automática. Duodécimo Workshop

    Get PDF
    Actas de los trabajos de TFM del Máster Universitario en Sistemas Inteligentes 2017-2018[ES]El Máster Oficial en Sistemas Inteligentes de la Universidad de Salamanca tiene como principal objetivo promover la iniciación de los estudiantes en el ámbito de la investigación. El congreso organizado por el Departamento de Informática y Automática que se celebra dentro del Máster en Sistemas Inteligentes de la Universidad de Salamanca proporciona la oportunidad ideal para que sus estudiantes presenten los principales resultados de sus Trabajos de Fin de Máster y obtengan una realimentación del interés de los mismos. La duodécima edición del workshop Avances en Informática y Automática, correspondiente al curso 2017-2018, ha sido un encuentro interdisciplinar donde se han presentado trabajos pertenecientes a un amplio abanico de líneas de investigación. Todos los trabajos han sido supervisados por investigadores de reconocido prestigio pertenecientes a la Universidad de Salamanca, proporcionando el marco idóneo para sentar las bases de una futura tesis doctoral. Entre los principales objetivos del congreso se encuentran: Ofrecer a los estudiantes un marco donde exponer sus primeros trabajos de investigación. Proporcionar a los participantes un foro donde discutir ideas y encontrar nuevas sugerencias de compañeros, investigadores y otros asistentes a la reunión. Permitir a cada estudiante una realimentación de los participantes sobre su trabajo y una orientación sobre las futuras direcciones de investigación. Contribuir al desarrollo del espíritu de colaboración en la investigación
    corecore