552 research outputs found

    Dissertation Abstracts

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    Exploring the use of protocols and guidelines in the management of healthcare-associated infection : a case study

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    Implementation of protocols and guidelines is an important strategy used by hospitals in their fight against healthcare-associated infections (Pratt et al., 2007), yet their use remains a challenge (Boaz et al., 2011; Grimshaw et al., 2001). This thesis addresses the topic of behavioural change through exploring how protocols and guidelines are used on hospital wards to manage the risk from Clostridium difficile infection, the difficulties ward staff faced with their use and what happened in practice as difficulties were experienced. A qualitative study was conducted using a single case study methodology (Yin, 2009) with one acute NHS hospital in the UK. Methods used included nonparticipant observation (184 hours), informal conversation, interviews (49) and document review. An adapted version of the topic guide developed by Michie et al. (2005) based on their theoretical framework of behavioural change was used in the interviews. Data collected was analysed inductively using NVivo 8 and compared against Michie et al’s (2005) framework. The findings illustrate that nurses and doctors were detached from protocols and guidelines. Instead they relied heavily on informal sources of knowledge to guide their practice. Examples include experiential knowledge, common sense, intuition, ‘‘rules of thumb’’ and “mind lines’’ (Gabbay and le May, 2004, 2011). They also took account of preferences, their perceptions of risk, social norms and other contextual issues. Four emergent themes illustrate the complexity of factors hindering and assisting the use of protocols and guidelines into practice. These are ambiguity, organisational issues, professional frustrations and perceptions of contamination. Variations in practice were widespread as protocols and guidelines were ‘worked around’ and improvisations were made as ward staff struggled against a tide of organisational constraints, unrealistic conflicting priorities and difficulties with protocol ambiguity. The way that difficulties were being solved on the ward means that the underlying causes were not being addressed as concerns were not brought to the surface. Professional frustrations such as feeling overwhelmed and powerless acted as barriers to nurses’ reflection. The study has empirically expanded Michie et al’s (2005) behavioural framework whilst exploring the dynamics and complexity of categories influencing the use of protocols and guidelines through a ‘thick’ description of the study findings. This study has made a conceptual contribution to the literature by identifying that Michie et al’s (2005) framework does not seem to take into account tacit and experiential knowledge, professional knowledge, how sense is made of information from the local context or the process of reflection as part of learning. Recommendations are made to address the findings from this study

    The Collection Efficiency of Shielded and Unshielded Precipitation Gauges. Part II: Modeling Particle Trajectories

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    The use of windshields to reduce the impact of wind on snow measurements is common. This paper investigates the catching performance of shielded and unshielded gauges using numerical simulations. In Part II, the role of the windshield and gauge aerodynamics, as well as the varying flow field due to the turbulence generated by the shield–gauge configuration, in reducing the catch efficiency is investigated. This builds on the computational fluid dynamics results obtained in Part I, where the airflow patterns in the proximity of an unshielded and single Alter shielded Geonor T-200B gauge are obtained using both time-independent [Reynolds-averaged Navier–Stokes (RANS)] and time-dependent [large-eddy simulation (LES)] approaches. A Lagrangian trajectory model is used to track different types of snowflakes (wet and dry snow) and to assess the variation of the resulting gauge catching performance with the wind speed. The collection efficiency obtained with the LES approach is generally lower than the one obtained with the RANS approach. This is because of the impact of the LES-resolved turbulence above the gauge orifice rim. The comparison between the collection efficiency values obtained in case of shielded and unshielded gauge validates the choice of installing a single Alter shield in a windy environment. However, time-dependent simulations show that the propagating turbulent structures produced by the aerodynamic response of the upwind single Alter blades have an impact on the collection efficiency. Comparison with field observations provides the validation background for the model results

    Low‐Fe(III) Greenalite Was a Primary Mineral From Neoarchean Oceans

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    Banded iron formations (BIFs) represent chemical precipitation from Earth’s early oceans and therefore contain insights into ancient marine biogeochemistry. However, BIFs have undergone multiple episodes of alteration, making it difficult to assess the primary mineral assemblage. Nanoscale mineral inclusions from 2.5 billion year old BIFs and ferruginous cherts provide new evidence that iron silicates were primary minerals deposited from the Neoarchean ocean, contrasting sharply with current models for BIF inception. Here we used multiscale imaging and spectroscopic techniques to characterize the best preserved examples of these inclusions. Our integrated results demonstrate that these early minerals were low‐Fe(III) greenalite. We present potential pathways in which low‐Fe(III) greenalite could have formed through changes in saturation state and/or iron oxidation and reduction. Future constraints for ancient ocean chemistry and early life’s activities should include low‐Fe(III) greenalite as a primary mineral in the Neoarchean ocean.Plain Language SummaryChemical precipitates from Earth’s early oceans hold clues to ancient seawater chemistry and biological activities, but we first need to understand what the original minerals were in ancient marine deposits. We characterized nanoscale mineral inclusions from 2.5 billion year old banded iron formations and determined that the primary minerals were iron‐rich silicate minerals dominated by reduced iron, challenging current hypotheses for banded iron formation centered on iron oxides. Our results suggest that our planet at this time had a very reducing ocean and further enable us to present several biogeochemical mineral formation hypotheses that can now be tested to better understand the activities of early life on ancient Earth.Key PointsNeoarchean nanoparticle silicate inclusions appear to be the earliest iron mineral preserved in cherts from Australia and South AfricaOur multiscale analyses indicate that the particles are greenalite that are dominantly Fe(II) with have low and variable Fe(III) contentWe present four (bio)geochemical hypotheses that could produce low‐Fe(III) greenalitePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143747/1/grl57046_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143747/2/grl57046.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143747/3/grl57046-sup-0001-2017GL076311-SI.pd

    Impact of Wind Direction, Wind Speed, and Particle Characteristics on the Collection Efficiency of the Double Fence Intercomparison Reference

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    The accurate measurement of snowfall is important in various fields of study such as climate variability, transportation, and water resources. A major concern is that snowfall measurements are difficult and can result in significant errors. For example, collection efficiency of most gauge–shield configurations generally decreases with increasing wind speed. In addition, much scatter is observed for a given wind speed, which is thought to be caused by the type of snowflake. Furthermore, the collection efficiency depends strongly on the reference used to correct the data, which is often the Double Fence Intercomparison Reference (DFIR) recommended by the World Meteorological Organization. The goal of this study is to assess the impact of weather conditions on the collection efficiency of the DFIR. Note that the DFIR is defined as a manual gauge placed in a double fence. In this study, however, only the double fence is being investigated while still being called DFIR. To address this issue, a detailed analysis of the flow field in the vicinity of the DFIR is conducted using computational fluid dynamics. Particle trajectories are obtained to compute the collection efficiency associated with different precipitation types for varying wind speed. The results show that the precipitation reaching the center of the DFIR can exceed 100% of the actual precipitation, and it depends on the snowflake type, wind speed, and direction. Overall, this study contributes to a better understanding of the sources of uncertainty associated with the use of the DFIR as a reference gauge to measure snowfall

    Cost of simulation-based mastery learning for abdominal ultrasound

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    BACKGROUND: Ultrasound is an essential diagnostic examination used in several medical specialties. However, the quality of ultrasound examinations is dependent on mastery of certain skills, which may be difficult and costly to attain in the clinical setting. This study aimed to explore mastery learning for trainees practicing general abdominal ultrasound using a virtual reality simulator and to evaluate the associated cost per student achieving the mastery learning level.METHODS: Trainees were instructed to train on a virtual reality ultrasound simulator until the attainment of a mastery learning level was established in a previous study. Automated simulator scores were used to track performances during each round of training, and these scores were recorded to determine learning curves. Finally, the costs of the training were evaluated using a micro-costing procedure.RESULTS: Twenty-one out of the 24 trainees managed to attain the predefined mastery level two times consecutively. The trainees completed their training with a median of 2h38min (range: 1h20min-4h30min) using a median of 7 attempts (range: 3-11 attempts) at the simulator test. The cost of training one trainee to the mastery level was estimated to be USD 638.CONCLUSION: Complete trainees can obtain mastery learning levels in general abdominal ultrasound examinations within 3 hours of training in the simulated setting and at an average cost of USD 638 per trainee. Future studies are needed to explore how the cost of simulation-based training is best balanced against the costs of clinical training.</p

    An Improved Trajectory Model to Evaluate the Collection Performance of Snow Gauges

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    Recent studies have used numerical models to estimate the collection efficiency\ud of solid precipitation gauges when exposed to the wind, in both\ud shielded and unshielded configurations. The models used computational fluid\ud dynamics (CFD) simulations of the airflow pattern generated by the aerodynamic\ud response to the gauge/shield geometry. These are used as initial conditions\ud to perform Lagrangian tracking of solid precipitation particles. Validation\ud of the results against field observations yielded similarities in the overall\ud behavior, but the model output only approximately reproduced the dependence\ud of the experimental collection efficiency on wind speed. This paper\ud presents an improved snowflake trajectory modeling scheme due to the inclusion\ud of a dynamically-determined drag coefficient. The drag coefficient\ud was estimated using the local Reynolds number as derived from CFD simulations\ud within a time-independent Reynolds Averaged Navier-Stokes (RANS)\ud approach. The proposed dynamic model greatly improves the consistency of\ud results with the field observations recently obtained at the Marshall, CO Winter\ud Precipitation Testbed

    On a learning curve for shared decision making: interviews with clinicians using the knee osteoarthritis Option Grid

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    Rational: Tools used in clinical encounters to illustrate to patients the risks and benefits of treatment options have been shown to increase shared decision making. However, we do not have good information about how these tools are viewed by clinicians, and how clinicians think patients would react to their use. Objective: Our aim was to examine clinicians’ views about the possible and actual use of tools designed to support patients and clinicians to collaborate and deliberate about treatment options, namely Option Grid TM decision aids. Method: We conducted a thematic analysis of qualitative interviews embedded in the intervention phase of a trial of an Option Grid decision aid for Osteoarthritis of the knee. Interviews were conducted with six participating clinicians before they used the tool, and again after clinicians had used the tool with six patients. Results: In the first interview, clinicians voiced concern that the tool would lead to an increase in encounter duration, to patient resistance regarding involvement in decision making, and potential information overload. At the second interview, after minimal training, the clinicians reported that the tool had changed their usual way of communicating, and it was generally acceptable and helpful integrate it into practice. Discussion and Conclusions: After experiencing the use of Option Grids, clinicians became more willing to use the tools in their clinical encounters with patients. How best to introduce Option Grids to clinicians and adopt their use into practice will need careful consideration of context, workflow and clinical pathways

    Simulation-based assessment of upper abdominal ultrasound skills

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    Background: Ultrasound is a safe and effective diagnostic tool used within several specialties. However, the quality of ultrasound scans relies on sufficiently skilled clinician operators. The aim of this study was to explore the validity of automated assessments of upper abdominal ultrasound skills using an ultrasound simulator. Methods: Twenty five novices and five experts were recruited, all of whom completed an assessment program for the evaluation of upper abdominal ultrasound skills on a virtual reality simulator. The program included five modules that assessed different organ systems using automated simulator metrics. We used Messick’s framework to explore the validity evidence of these simulator metrics to determine the contents of a final simulator test. We used the contrasting groups method to establish a pass/fail level for the final simulator test. Results: Thirty seven out of 60 metrics were able to discriminate between novices and experts (p &lt; 0.05). The median simulator score of the final simulator test including the metrics with validity evidence was 26.68% (range: 8.1–40.5%) for novices and 85.1% (range: 56.8–91.9%) for experts. The internal structure was assessed by Cronbach alpha (0.93) and intraclass correlation coefficient (0.89). The pass/fail level was determined to be 50.9%. This pass/fail criterion found no passing novices or failing experts. Conclusions: This study collected validity evidence for simulation-based assessment of upper abdominal ultrasound examinations, which is the first step toward competency-based training. Future studies may examine how competency-based training in the simulated setting translates into improvements in clinical performances.</p
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