977 research outputs found

    Sulphur-bearing molecules in AGB stars I: The occurrence of hydrogen sulfide

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    Through a survey of (sub-)millimetre emission lines of various sulphur-bearing molecules, we aim to determine which molecules are the primary carriers of sulphur in different types of AGB stars. In this paper, the first in a series, we investigate the occurrence of H2_2S in AGB circumstellar envelopes and determine its abundance, where possible. We have surveyed 20 AGB stars with a range of mass-loss rates and of different chemical types using the APEX telescope to search for rotational transition lines of five key sulphur-bearing molecules: CS, SiS, SO, SO2_2 and H2_2S. Here we present our results for H2_2S, including detections, non-detections and detailed radiative transfer modelling of the detected lines. We compare results based on different descriptions of the molecular excitation of H2_2S and different abundance distributions, including those derived from chemical modelling results. We detected H2_2S towards five AGB stars, all of which have high mass-loss rates of M˙5×106M\dot{M}\geq 5\times 10^{-6}M_\odot yr1^{-1} and are oxygen-rich. H2_2S was not detected towards the carbon or S-type stars that fall in a similar mass-loss range. For the stars in our sample with detections, we find peak o-H2_2S abundances relative to H2_2 between 4×1074\times 10^{-7} and 2.5×1052.5\times 10^{-5}. Overall, we conclude that H2_2S can play a significant role in oxygen-rich AGB stars with higher mass-loss rates, but is unlikely to play a key role in stars of other chemical types or the lower mass-loss rate oxygen-rich stars. For two sources, V1300 Aql and GX Mon, H2_2S is most likely the dominant sulphur-bearing molecule in the circumstellar envelope.Comment: 14 pages, 7 figures, accepted in A&

    Measurements of Low Temperature Rate Coefficients for the Reaction of CH with CH₂O and Application to Dark Cloud and AGB Stellar Wind Models

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    Rate coefficients have been measured for the reaction of CH radicals with formaldehyde, CH₂O, over the temperature range of 31–133 K using a pulsed Laval nozzle apparatus combined with pulsed laser photolysis and laser-induced fluorescence spectroscopy. The rate coefficients are very large and display a distinct decrease with decreasing temperature below 70 K, although classical collision rate theory fails to reproduce this temperature dependence. The measured rate coefficients have been parameterized and used as input for astrochemical models for both dark cloud and Asymptotic Giant Branch stellar outflow scenarios. The models predict a distinct change (up to a factor of two) in the abundance of ketene, H₂CCO, which is the major expected molecular product of the CH + CH₂O reaction

    Generating insights in uncharted territories:Real-time learning from data in critically ill patients-an implementer report

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    Introduction In the current situation, clinical patient data are often siloed in multiple hospital information systems. Especially in the intensive care unit (ICU), large volumes of clinical data are routinely collected through continuous patient monitoring. Although these data often contain useful information for clinical decision making, they are not frequently used to improve quality of care. During, but also after, pressing times, data-driven methods can be used to mine treatment patterns from clinical data to determine the best treatment options from a hospitals own clinical data. Methods In this implementer report, we describe how we implemented a data infrastructure that enabled us to learn in real time from consecutive COVID-19 ICU admissions. In addition, we explain our step-by-step multidisciplinary approach to establish such a data infrastructure. Conclusion By sharing our steps and approach, we aim to inspire others, in and outside ICU walls, to make more efficient use of data at hand, now and in the future

    Zinc-Embedded Polyamide Fabrics Inactivate SARS-CoV-2 and Influenza A Virus.

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    Influenza A viruses (IAV) and SARS-CoV-2 can spread via liquid droplets and aerosols. Face masks and other personal protective equipment (PPE) can act as barriers that prevent the spread of these viruses. However, IAV and SARS-CoV-2 are stable for hours on various materials, which makes frequent and correct disposal of these PPE important. Metal ions embedded into PPE may inactivate respiratory viruses, but confounding factors such as adsorption of viruses make measuring and optimizing the inactivation characteristics difficult. Here, we used polyamide 6.6 (PA66) fibers containing embedded zinc ions and systematically investigated if these fibers can adsorb and inactivate SARS-CoV-2 and IAV H1N1 when woven into a fabric. We found that our PA66-based fabric decreased the IAV H1N1 and SARS-CoV-2 titer by approximately 100-fold. Moreover, we found that the zinc content and the virus inactivating property of the fabric remained stable over 50 standardized washes. Overall, these results provide insights into the development of reusable PPE that offer protection against RNA virus spread

    Signatures of internal rotation discovered in the Kepler data of five slowly pulsating B stars

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    Context. Massive stars are important building blocks of the Universe, and their stellar structure and evolution models are fundamental cornerstones of various fields in modern astrophysics. The precision of these models is strongly limited by our lack of understanding of various internal mixing processes that significantly influence the lifetime of these objects, such as core overshoot, chemical mixing, or the internal differential rotation. Aims. Our goal is to calibrate models by extending the sample of available seismic studies of slowly pulsating B (SPB) stars, providing input for theoretical modelling efforts that will deliver precise constraints on the parameters describing the internal mixing processes in these objects. Methods. We used spectral synthesis and disentangling techniques to derive fundamental parameters and to determine precise orbital parameters from high-resolution spectra. We employed custom masks to construct light curves from the virtually uninterrupted four year long Kepler pixel data and used standard time-series analysis tools to construct a set of significant frequencies for each target. These sets were first filtered from combination frequencies, and then screened for period spacing patterns. Results. We detect gravity mode period series of modes, of the same degree ℓ with consecutive radial order n, in four new and one revisited SPB star. These series (covering typically 10 to 40 radial orders) are clearly influenced by moderate to fast rotation and carry signatures of chemical mixing processes. Furthermore, they are predominantly prograde dipole series. Our spectroscopic analysis, in addition to placing each object inside the SPB instability strip and identifying KIC 4930889 as an SB2 binary, reveals that KIC 11971405 is a fast rotator that shows very weak Be signatures. Together with the observed photometric outbursts this illustrates that this Be star is a fast rotating SPB star. We hypothesise that the outbursts might be connected to its very densely compressed oscillation spectrum

    Нарративное интервью в исследовании катамнеза внутренней картины болезни при шизофрении (клинико-психологический аспект)

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    Представлены особенности проведения клинического нарративного интервью как значимого метода в психодиагностике внутренней картины болезни (ВКБ) в катамнезе у больных шизофренией. Проведено комплексное психоанамнестическое, психодиагностическое, патоперсонологическое обследование больных параноидной шизофренией. Сформулированы стратегии и тактики проведения нарративного интервью с целью выявления особенностей их ВКБ.Наведено особливості проведення клінічного наративного інтерв'ю як визначального методу в психодіагностиці внутрішньої картини хвороби (ВКХ) у катамнезі у хворих на шизофренію. Проведено комплексне психоанамнестичне, психодіагностичне, патоперсонологічне обстеження хворих на параноїдну шизофренію. Сформульовано стратегії і тактики проведення наративного інтерв'ю з метою виявлення особливостей їх ВКХ.The peculiarities of clinical narrative interview as a significant method in psychodagnosis of the disease inner picture (DIP) in the history of patients with schizophrenia are presented. Complex psychoanamnestic, psychodiagnostic, pathopersonological investigation of patients with paranoid schizophrenia was performed. The strategies and tactics of narrative interview with the purpose to reveal DIP peculiarities were formulated

    The Artist-Shaman and the \"Gift of Sight\"

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    Throughout the history of art the role of the artist has been compared to the role of the shaman. This is because the artist’s role has always been one of mediator, transformer and most prominently visionary. The role of both the artist and shaman has always been to stand between two worlds: that of the visible and the invisible. The viewers, or the community in the case of the shaman, entrust the artist to go forth into the realm of the invisible and return with a gift: the invisible transformed into the visible. Traditionally, many artists associated with shamanism such as Joseph Beuys, Max Ernst, Leonora Carrington and later Matthew Barney, have been leaders, idealists, heroes of mythic proportions, artists who return with this gift: a vision or sight to follow. But a different breed of artist associated with shamanism also exists: an ambivalent artist-shaman, a shifty and unreliable character of dubious motivations, who appears to offer the viewer a vision or sight and then throws it back in their face, makes them decide. This is the role that Hany Armanious, John Bock, Carla Cescon, Marcus Coates, Mikala Dwyer, Steinar Haga Kristensen, Jonathan Meese, Paul Thek, Justene Williams and myself have taken. And we take it so as to return to the viewer the very power that is invested in the artist, that of creating a vision: what Rex Butler refers to in relation to Hany Armanious as the “gift of sight.” (Butler 2000). These artists and myself offer the “gift of sight” by reflecting the act of perception and by engaging the viewer in the same process that the artist goes through. The way we do this is by setting up complex, multi-positional, process-based systems that are highly informed and engaging but do not lead to an end position. Because the artist does not presume to idealise this end position, the result is inevitably confusing, slippery, uncertain, and ambivalent, as if the artist has no position or avoids commitment. This thesis sets out to inves! tigate t his ambivalent position taken by the artist-shaman and to show how and why it is taken. It does this in two ways. Firstly it provides a studio component as a practical example of the practice of an artist-shaman who offers the “gift of sight.” Secondly, the written dissertation provides a theory and understanding of the artist-shaman who offers the “gift of sight.” This may then be applied to the practical component, offering a historical and philosophical context with which to frame it
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