| 1. |
- Berne, Olivier, et al.
(author)
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PDRs4All : A JWST Early Release Science Program on Radiative Feedback from Massive Stars
- 2022
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In: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 134:1035
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Journal article (peer-reviewed)abstract
- Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy and throughout the universe, from the era of vigorous star formation at redshifts of 1-3 to the present day. The dominant feedback processes can be probed by observations of the Photo-Dissociation Regions (PDRs) where the far-ultraviolet photons of massive stars create warm regions of gas and dust in the neutral atomic and molecular gas. PDR emission provides a unique tool to study in detail the physical and chemical processes that are relevant for most of the mass in inter- and circumstellar media including diffuse clouds, proto-planetary disks, and molecular cloud surfaces, globules, planetary nebulae, and star-forming regions. PDR emission dominates the infrared (IR) spectra of star-forming galaxies. Most of the Galactic and extragalactic observations obtained with the James Webb Space Telescope (JWST) will therefore arise in PDR emission. In this paper we present an Early Release Science program using the MIRI, NIRSpec, and NIRCam instruments dedicated to the observations of an emblematic and nearby PDR: the Orion Bar. These early JWST observations will provide template data sets designed to identify key PDR characteristics in JWST observations. These data will serve to benchmark PDR models and extend them into the JWST era. We also present the Science-Enabling products that we will provide to the community. These template data sets and Science-Enabling products will guide the preparation of future proposals on star-forming regions in our Galaxy and beyond and will facilitate data analysis and interpretation of forthcoming JWST observations.
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| 2. |
- Peeters, Els, et al.
(author)
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PDRs4All: III. JWST's NIR spectroscopic view of the Orion Bar
- 2024
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In: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 685
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Journal article (peer-reviewed)abstract
- Context. JWST has taken the sharpest and most sensitive infrared (IR) spectral imaging observations ever of the Orion Bar photodis-sociation region (PDR), which is part of the nearest massive star-forming region the Orion Nebula, and often considered to be the 'prototypical'strongly illuminated PDR. Aims. We investigate the impact of radiative feedback from massive stars on their natal cloud and focus on the transition from the H II region to the atomic PDR -crossing the ionisation front (IF) -, and the subsequent transition to the molecular PDR -crossing the dissociation front (DF). Given the prevalence of PDRs in the interstellar medium and their dominant contribution to IR radiation, understanding the response of the PDR gas to far-ultraviolet (FUV) photons and the associated physical and chemical processes is fundamental to our understanding of star and planet formation and for the interpretation of any unresolved PDR as seen by JWST. Methods. We used high-resolution near-IR integral field spectroscopic data from NIRSpec on JWST to observe the Orion Bar PDR as part of the PDRs4All JWST Early Release Science programme. We constructed a 3″ × 25″ spatio-spectral mosaic covering 0.97-5.27 μm at a spectral resolution R of ~2700 and an angular resolution of 0.075″-0.173″. To study the properties of key regions captured in this mosaic, we extracted five template spectra in apertures centred on the three H2 dissociation fronts, the atomic PDR, and the H II region. This wealth of detailed spatial-spectral information was analysed in terms of variations in the physical conditions-incident UV field, density, and temperature -of the PDR gas. Results. The NIRSpec data reveal a forest of lines including, but not limited to, He I, H I, and C I recombination lines; ionic lines (e.g. Fe III and Fe II); O I and N I fluorescence lines; aromatic infrared bands (AIBs, including aromatic CH, aliphatic CH, and their CD counterparts); pure rotational and ro-vibrational lines from H2; and ro-vibrational lines from HD, CO, and CH+, with most of them having been detected for the first time towards a PDR. Their spatial distribution resolves the H and He ionisation structure in the Huygens region, gives insight into the geometry of the Bar, and confirms the large-scale stratification of PDRs. In addition, we observed numerous smaller-scale structures whose typical size decreases with distance from θ1 Ori C and IR lines from C I, if solely arising from radiative recombination and cascade, reveal very high gas temperatures (a few 1000 K) consistent with the hot irradiated surface of small-scale dense clumps inside the PDR. The morphology of the Bar, in particular that of the H2 lines, reveals multiple prominent filaments that exhibit different characteristics. This leaves the impression of a 'terraced'transition from the predominantly atomic surface region to the CO-rich molecular zone deeper in. We attribute the different characteristics of the H2 filaments to their varying depth into the PDR and, in some cases, not reaching the C+/C/CO transition. These observations thus reveal what local conditions are required to drive the physical and chemical processes needed to explain the different characteristics of the DFs and the photochemical evolution of the AIB carriers. Conclusions. This study showcases the discovery space created by JWST to further our understanding of the impact radiation from young stars has on their natal molecular cloud and proto-planetary disk, which touches on star and planet formation as well as galaxy evolution.
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| 3. |
- Robert, Glenn, et al.
(author)
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Exploring the sustainability of quality improvement interventions in healthcare organisations : a multiple methods study of the 10-year impact of the 'Productive Ward
- 2020
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In: BMJ Quality and Safety. - : BMJ Publishing Group Ltd. - 2044-5415 .- 2044-5423. ; 29, s. 31-40
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Journal article (peer-reviewed)abstract
- BACKGROUND: The 'Productive Ward: Releasing Time to Care' programme is a quality improvement (QI) intervention introduced in English acute hospitals a decade ago to: (1) Increase time nurses spend in direct patient care. (2) Improve safety and reliability of care. (3) Improve experience for staff and patients. (4) Make changes to physical environments to improve efficiency.OBJECTIVE: To explore how timing of adoption, local implementation strategies and processes of assimilation into day-to-day practice relate to one another and shape any sustained impact and wider legacies of a large-scale QI intervention.DESIGN: Multiple methods within six hospitals including 88 interviews (with Productive Ward leads, ward staff, Patient and Public Involvement representatives and senior managers), 10 ward manager questionnaires and structured observations on 12 randomly selected wards.RESULTS: Resource constraints and a managerial desire for standardisation meant that, over time, there was a shift away from the original vision of empowering ward staff to take ownership of Productive Ward towards a range of implementation 'short cuts'. Nonetheless, material legacies (eg, displaying metrics data; storage systems) have remained in place for up to a decade after initial implementation as have some specific practices (eg, protected mealtimes). Variations in timing of adoption, local implementation strategies and contextual changes influenced assimilation into routine practice and subsequent legacies. Productive Ward has informed wider organisational QI strategies that remain in place today and developed lasting QI capabilities among those meaningfully involved in its implementation.CONCLUSIONS: As an ongoing QI approach Productive Ward has not been sustained but has informed contemporary organisational QI practices and strategies. Judgements about the long-term sustainability of QI interventions should consider the evolutionary and adaptive nature of change processes.
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| 4. |
- Sarre, Sophie, et al.
(author)
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The 10-year impact of a ward-level quality improvement intervention in acute hospitals : a multiple methods study
- 2019
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In: Health Services and Delivery Research. - : National Institute of Health Research. - 2050-4349 .- 2050-4357. ; 7:28
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Journal article (peer-reviewed)abstract
- BackgroundThe ‘Productive Ward: Releasing Time to Care’™ programme (Productive Ward; PW) was introduced in English NHS acute hospitals in 2007 to give ward staff the tools, skills and time needed to implement local improvements to (1) increase the time nurses spend on direct patient care, (2) improve the safety and reliability of care, (3) improve staff and patient experience and (4) make structural changes on wards to improve efficiency. Evidence of whether or not these goals were met and sustained is very limited.ObjectiveTo explore if PW had a sustained impact over the past decade.DesignMultiple methods, comprising two online national surveys, six acute trust case studies (including a secondary analysis of local audit data) and telephone interviews.Data sourcesSurveys of 56 directors of nursing and 35 current PW leads; 88 staff and patient and public involvement representative interviews; 10 ward manager questionnaires; structured observations of 12 randomly selected wards and documentary analysis in case studies; and 14 telephone interviews with former PW leads.ResultsTrusts typically adopted PW in 2008–9 on their wards using a phased implementation approach. The average length of PW use was 3 years (range < 1 to 7 years). Financial and management support for PW has disappeared in the majority of trusts. The most commonly cited reason for PW’s cessation was a change in quality improvement (QI) approach. Nonetheless, PW has influenced wider QI strategies in around half of the trusts. Around one-third of trusts had impact data relating specifically to PW; the same proportion did not. Early adopters of PW had access to more resources for supporting implementation. Some elements of local implementation strategies were common. However, there were variations that had consequences for the assimilation of PW into routine practice and, subsequently, for the legacies and sustainability of the programme. In all case study sites, material legacies (e.g. display of metrics data; storage systems) remained, as did some processes (e.g. protected mealtimes). Only one case study site had sufficiently robust data collection systems to allow an objective assessment of PW’s impact; in that site, care processes had improved initially (in terms of patient observations and direct care time). Experience of leading PW had benefited the careers of the majority of interviewees. Starting with little or no QI experience, many went on to work on other initiatives within their trusts, or to work in QI at regional or national level within the NHS or in the private sector.LimitationsThe research draws on participant recall over a lengthy period characterised by evolving QI approaches and system-level change.ConclusionsLittle robust evidence remains of PW leading to a sustained increase in the time nurses spend on direct patient care or improvements in the experiences of staff and/or patients. PW has had a lasting impact on some ward practices. As an ongoing QI approach continually used to make ongoing improvements, PW has not been sustained, but it has informed current organisational QI practices and strategies in many trusts. The design and delivery of future large-scale QI programmes could usefully draw on the lessons learnt from this study of the PW in England over the period 2008–18.
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