350 research outputs found

    Music in Action: Tinkering, Testing, and Tracing Over Time

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    ArticleThis is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.In this article we draw on a recent, six-year ethnographic study of community music therapy and mental health to highlight strategies and techniques for documenting music’s role in processes of change. We place these strategies in dialogue with the ethnographic work on arts and crafts by Paul Atkinson. In tandem with Atkinson, we propose a ‘slow’ approach focused on micro-processes of musical/para-musical bricolage whereby things are made and transformed over time. A three-cornered strategy in support of this approach is described: (1) a focus on musical-practical tinkering, (2) a focus on the modification and contention or testing of idiocultural musical space and, (3) two specific techniques for tracing music-related change, the music therapy ‘index’ and the ‘musical event’ schema

    Young "Dipper" Stars in Upper Sco and ρ\rho Oph Observed by K2

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    We present ten young (\lesssim10 Myr) late-K and M dwarf stars observed in K2 Campaign 2 that host protoplanetary disks and exhibit quasi-periodic or aperiodic dimming events. Their optical light curves show \sim10-20 dips in flux over the 80-day observing campaign with durations of \sim0.5-2 days and depths of up to \sim40%. These stars are all members of the ρ\rho Ophiuchus (\sim1 Myr) or Upper Scorpius (\sim10 Myr) star-forming regions. To investigate the nature of these "dippers" we obtained: optical and near-infrared spectra to determine stellar properties and identify accretion signatures; adaptive optics imaging to search for close companions that could cause optical variations and/or influence disk evolution; and millimeter-wavelength observations to constrain disk dust and gas masses. The spectra reveal Li I absorption and Hα\alpha emission consistent with stellar youth (<50 Myr), but also accretion rates spanning those of classical and weak-line T Tauri stars. Infrared excesses are consistent with protoplanetary disks extending to within \sim10 stellar radii in most cases; however, the sub-mm observations imply disk masses that are an order of magnitude below those of typical protoplanetary disks. We find a positive correlation between dip depth and WISE-2 excess, which we interpret as evidence that the dipper phenomenon is related to occulting structures in the inner disk, although this is difficult to reconcile with the weakly accreting aperiodic dippers. We consider three mechanisms to explain the dipper phenomenon: inner disk warps near the co-rotation radius related to accretion; vortices at the inner disk edge produced by the Rossby Wave Instability; and clumps of circumstellar material related to planetesimal formation.Comment: Accepted to ApJ, 19 pages, 10 figure

    Demographics of young stars and their protoplanetary disks: lessons learned on disk evolution and its connection to planet formation

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    Since Protostars and Planets VI (PPVI), our knowledge of the global properties of protoplanetary and debris disks, as well as of young stars, has dramatically improved. At the time of PPVI, mm-observations and optical to near-infrared spectroscopic surveys were largely limited to the Taurus star-forming region, especially of its most massive disk and stellar population. Now, near-complete surveys of multiple star-forming regions cover both spectroscopy of young stars and mm interferometry of their protoplanetary disks. This provides an unprecedented statistical sample of stellar masses and mass accretion rates, as well as disk masses and radii, for almost 1000 young stellar objects within 300 pc from us, while also sampling different evolutionary stages, ages, and environments. At the same time, surveys of debris disks are revealing the bulk properties of this class of more evolved objects. This chapter reviews the statistics of these measured global star and disk properties and discusses their constraints on theoretical models describing global disk evolution. Our comparisons of observations to theoretical model predictions extends beyond the traditional viscous evolution framework to include analytical descriptions of magnetic wind effects. Finally, we discuss how recent observational results can provide a framework for models of planet population synthesis and planet formation.Comment: Review Chapter for Protostars and Planets VII, Editors: Shu-ichiro Inutsuka, Yuri Aikawa, Takayuki Muto, Kengo Tomida, and Motohide Tamura. Accepted version after interaction with the referees and before community feedback. 21 pages (24 with references), 8 figures. Data table available at http://ppvii.org/chapter/15

    Are inner disc misalignments common? ALMA reveals an isotropic outer disc inclination distribution for young dipper stars

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    Dippers are a common class of young variable star exhibiting day-long dimmings with depths of up to several tens of per cent. A standard explanation is that dippers host nearly edge-on (id ≈ 70°) protoplanetary discs that allow close-in (10 au) disc resolved by ALMA and that inner disc misalignments may be common during the protoplanetary phase. More than one mechanism may contribute to the dipper phenomenon, including accretion-driven warps and ‘broken’ discs caused by inclined (sub-)stellar or planetary companions

    Wound irrigation does not affect healthrelated quality of life after open fractures: Results of a randomized controlled trial

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    © 2018 Sprague et al. Aims The Fluid Lavage in Open Fracture Wounds (FLOW) trial was a multicentre, blinded, randomized controlled trial that used a 2 3 factorial design to evaluate the effect of irrigation solution (soap versus normal saline) and irrigation pressure (very low versus low versus high) on health-related quality of life (HRQL) in patients with open fractures. In this study, we used this dataset to ascertain whether these factors affect whether HRQL returns to pre-injury levels at 12-months post-injury. Patients and Methods Participants completed the Short Form-12 (SF-12) and the EuroQol-5 Dimensions (EQ-5D) at baseline (pre-injury recall), at two and six weeks, and at three, six, nine and 12-months postfracture. We calculated the Physical Component Score (PCS) and the Mental Component Score (MCS) of the SF-12 and the EQ-5D utility score, conducted an analysis using a multilevel generalized linear model, and compared differences between the baseline and 12- month scores. Results We found no clinically important differences between irrigating solutions or pressures for the SF-12 PCS, SF-12 MCS and EQ-5D. Irrespective of treatment, participants had not returned to their pre-injury function at 12-months for any of the three outcomes (p \u3c 0.001). Conclusion Neither the composition of the irrigation solution nor irrigation pressure applied had an effect on HRQL. Irrespective of treatment, patients had not returned to their pre-injury HRQL at 12 months post-fracture

    Testing external photoevaporation in the σ\sigma-Orionis cluster with spectroscopy and disk mass measurements

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    The evolution of protoplanetary disks is regulated by an interplay of several processes, either internal to the system or related to the environment. As most of the stars and planets have formed in massive stellar clusters, studying the effects of UV radiation on disk evolution is of paramount importance. Here we test the impact of external photoevaporation on the evolution of disks in the σ\sigma Orionis cluster by conducting the first combined large-scale UV to IR spectroscopic and mm-continuum survey of this region. We study a sample of 50 targets located at increasing distances from the central, OB system σ\sigma Ori. We combine new VLT/X-Shooter spectra with new and previously published ALMA measurements of disk dust and gas fluxes and masses. We confirm the previously found decrease of MdustM_{\rm dust} in the inner \sim0.5 pc of the cluster. This is particularly evident when considering the disks around the more massive stars (\ge 0.4 MM_{\odot}), where those located in the inner part (<< 0.5 pc) have MdustM_{\rm dust} about an order of magnitude lower than the more distant ones. About half of the sample is located in the region of the M˙acc\dot{M}_{\rm acc} vs MdiskM_{\rm disk} expected by models of external photoevaporation, namely showing shorter disk lifetimes. These are observed for all targets with projected separation from σ\sigma Ori << 0.5 pc, proving that the presence of a massive stellar system affects disk evolution. External photoevaporation is a viable mechanism to explain the observed shorter disk lifetimes and lower MdustM_{\rm dust} in the inner \sim0.5 pc of the cluster. Follow-up observations of the low stellar mass targets are crucial to confirm the dependence of the external photoevaporation process with stellar host mass. This work confirms that the effects of external photoevaporation are significant down to impinging radiation as low as 104\sim 10^{4} G0_0.Comment: Accepted for publication on Astronomy & Astrophysics. 13 pages, 7 figures + appendix. Abstract abridged to meet arXiv requirement
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