123 research outputs found

    Statistical Bias in the Hubble Constant and Mass Power Law Slope for Mock Strong Lenses

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    Strong gravitational lensing offers constraints on the Hubble constant that are independent of other methods. However, those constraints are subject to uncertainties in lens models. Previous studies suggest that using an elliptical power law + external shear (EPL+XS) for the lensing galaxy can yield results that are precise but inaccurate. We examine such models by generating and fitting mock lenses which produces multiple images of a background quasar-like point source. Despite using the same model for input and output, we find statistical bias in the Hubble constant on the order of 3% to 5%, depending on whether the elliptical lenses have noise or not. The phase space distribution has a `flared' shape that causes the mass power law slope to be underestimated and the Hubble constant to be overestimated. The bias varies with image configuration, which we quantify through annulus length between images with the first and second time delays (Δr1,2\Delta r_{1,2}). The statistical bias is worse for configurations that have narrow annuli (e.g., symmetric cross configurations). Assuming a source at redshift 2.0 and an EPL+XS lens at redshift 0.3, we find that the bias can be reduced, but not eliminated, if we limit the sample to systems with annulus lengths Δr1,2≳0.3\Delta r_{1,2} \gtrsim 0.3 arcsec. As lens samples grow, it may be helpful to prioritize this range of image configurations for follow-up observation and analysis.Comment: Submitted to MNRA

    Diagnosis and management of postpartum hemorrhage and intrapartum asphyxia in a quality improvement initiative using nurse-mentoring and simulation in Bihar, India.

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    BackgroundIn the state of Bihar, India a multi-faceted quality improvement nurse-mentoring program was implemented to improve provider skills in normal and complicated deliveries. The objective of this analysis was to examine changes in diagnosis and management of postpartum hemorrhage (PPH) of the mother and intrapartum asphyxia of the infant in primary care facilities in Bihar, during the program.MethodsDuring the program, mentor pairs visited each facility for one week, covering four facilities over a four-week period and returned for subsequent week-long visits once every month for seven to nine consecutive months. Between- and within-facility comparisons were made using a quasi-experimental and a longitudinal design over time, respectively, to measure change due to the intervention. The proportions of PPH and intrapartum asphyxia among all births as well as the proportions of PPH and intrapartum asphyxia cases that were effectively managed were examined. Zero-inflated negative binomial models and marginal structural methodology were used to assess change in diagnosis and management of complications after accounting for clustering of deliveries within facilities as well as time varying confounding.ResultsThis analysis included 55,938 deliveries from 320 facilities. About 2% of all deliveries, were complicated with PPH and 3% with intrapartum asphyxia. Between-facility comparisons across phases demonstrated diagnosis was always higher in the final week of intervention (PPH: 2.5-5.4%, intrapartum asphyxia: 4.2-5.6%) relative to the first week (PPH: 1.2-2.1%, intrapartum asphyxia: 0.7-3.3%). Within-facility comparisons showed PPH diagnosis increased from week 1 through 5 (from 1.6% to 4.4%), after which it decreased through week 7 (3.1%). A similar trend was observed for intrapartum asphyxia. For both outcomes, the proportion of diagnosed cases where selected evidence-based practices were used for management either remained stable or increased over time.ConclusionsThe nurse-mentoring program appears to have built providers' capacity to identify PPH and intrapartum asphyxia cases but diagnosis levels are still not on par with levels observed in Southeast Asia and globally

    Introducing service improvement to the initial training of clinical staff

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    BACKGROUND: It is well recognised in healthcare settings that clinical staff have a major influence over change in how services are provided. If a culture of systematic service improvement is to be established, it is essential that clinical staff have an understanding of what is required and their role in its application. METHODS: This paper describes the development of short educational interventions (a module of 6-8 contact hours or a longer module of 18-30 h) for inclusion in the initial training of future clinical staff (nursing, medicine, physiotherapy, occupational therapy, dietetics, social work, operating department practice, public health and clinical psychology) and presents the results of an evaluation of their introduction. Each module included teaching on process/systems thinking, initiating and sustaining change, personal and organisational development, and public and patient involvement. RESULTS: Over 90% of students considered the modules relevant to their career. Nearly 90% of students felt that they could put their learning into practice, although the actual rate of implementation of changes during the pilot period was much lower. The barriers to implementation most commonly cited were blocks presented by existing staff, lack of time and lack of status of students within the workforce. CONCLUSION: This pilot demonstrates that short educational interventions focused on service improvement are valued by students and that those completing them feel ready to contribute. Nevertheless, the rate of translation into practice is low. While this may reflect the status of students in the health service, further research is needed to understand how this might be enhanced
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