Evaluation of WRF-Sfire Performance with Field Observations from the FireFlux experiment

This study uses in-situ measurements collected during the FireFlux field experiment to evaluate and improve the performance of coupled atmosphere-fire model WRF-Sfire. The simulation by WRF-Sfire of the experimental burn shows that WRF-Sfire is capable of providing realistic head fire rate-of-spread and the vertical temperature structure of the fire plume, and, up to 10 m above ground level, fire-induced surface flow and vertical velocities within the plume. The model captured the changes in wind speed and direction before, during, and after fire front passage, along with arrival times of wind speed, temperature, and updraft maximae, at the two instrumented flux towers used in FireFlux. The model overestimated vertical velocities and underestimated horizontal wind speeds measured at tower heights above the 10 m, and it is hypothesized that the limited model resolution over estimated the fire front depth, leading to too high a heat release and, subsequently, too strong an updraft. However, on the whole, WRF-Sfire fire plume behavior is consistent with the interpretation of FireFlux observations. The study suggests optimal experimental pre-planning, design, and execution of future field campaigns that are needed for further coupled atmosphere-fire model development and evaluation

Too Much of a Good Thing? Overexertion of Self-Control and Dietary Adherence in Individuals with Type 2 Diabetes

Objectives The resource model of self‐control posits that self‐control is a finite resource that can be depleted. Individuals with diabetes must continually restrict their diet, requiring self‐control. As a result, dietary adherence is difficult, and lapses are common. People with diabetes who overexert self‐control following a lapse may be especially likely to experience a subsequent relapse, as suggested by the resource model. This investigation used the resource model of self‐control to test whether overexertion of dietary self‐control following a lapse would be predictive of a subsequent relapse in dietary control. Design We tested this prediction in a daily diary study of 128 individuals with diabetes (Mage = 66.12). Methods Participants\u27 reports of their daily dietary adherence were used to define lapses in adherence, post‐lapse adherence, and relapses. Results Individuals who overexerted self‐control after a lapse were more likely to experience a subsequent relapse (OR = 3.276, p = .016) and to do so sooner (HR = 2.12, p = .023). Conclusions People with diabetes may seek to compensate for a lapse in adherence by overexerting self‐control, but doing so may deplete their self‐control and increase the risk of a future relapse

Sustaining organizational culture change in health systems

Purpose – The questions addressed by this review are: first, what are the guiding principles underlying efforts to stimulate sustained cultural change; second, what are the mechanisms by which these principles operate; and, finally, what are the contextual factors that influence the likelihood of these principles being effective? The paper aims to discuss these issues. Design/methodology/approach – The authors conducted a literature review informed by rapid realist review methodology that examined how interventions interact with contexts and mechanisms to influence the sustainability of cultural change. Reference and expert panelists assisted in refining the research questions, systematically searching published and grey literature, and helping to identify interactions between interventions, mechanisms and contexts. Findings – Six guiding principles were identified: align vision and action; make incremental changes within a comprehensive transformation strategy; foster distributed leadership; promote staff engagement; create collaborative relationships; and continuously assess and learn from change. These principles interact with contextual elements such as local power distributions, pre-existing values and beliefs and readiness to engage. Mechanisms influencing how these principles sustain cultural change include activation of a shared sense of urgency and fostering flexible levels of engagement. Practical implications – The principles identified in this review, along with the contexts and mechanisms that influence their effectiveness, are useful domains for policy and practice leaders to explore when grappling with cultural change. These principles are sufficiently broad to allow local flexibilities in adoption and application. Originality/value – This is the first study to adopt a realist approach for understanding how changes in organizational culture may be sustained. Through doing so, this review highlights the broad principles by which organizational action may be organized within enabling contextual settings.</p

Acceleration of dormant storage effects to address the reliability of silicon surface micromachined Micro-Electro-Mechanical Systems (MEMS).

Qualification of microsystems for weapon applications is critically dependent on our ability to build confidence in their performance, by predicting the evolution of their behavior over time in the stockpile. The objective of this work was to accelerate aging mechanisms operative in surface micromachined silicon microelectromechanical systems (MEMS) with contacting surfaces that are stored for many years prior to use, to determine the effects of aging on reliability, and relate those effects to changes in the behavior of interfaces. Hence the main focus was on 'dormant' storage effects on the reliability of devices having mechanical contacts, the first time they must move. A large number ({approx}1000) of modules containing prototype devices and diagnostic structures were packaged using the best available processes for simple electromechanical devices. The packaging processes evolved during the project to better protect surfaces from exposure to contaminants and water vapor. Packages were subjected to accelerated aging and stress tests to explore dormancy and operational environment effects on reliability and performance. Functional tests and quantitative measurements of adhesion and friction demonstrated that the main failure mechanism during dormant storage is change in adhesion and friction, precipitated by loss of the fluorinated monolayer applied after fabrication. The data indicate that damage to the monolayer can occur at water vapor concentrations as low as 500 ppm inside the package. The most common type of failure was attributed to surfaces that were in direct contact during aging. The application of quantitative methods for monolayer lubricant analysis showed that even though the coverage of vapor-deposited monolayers is generally very uniform, even on hidden surfaces, locations of intimate contact can be significantly depleted in initial concentration of lubricating molecules. These areas represent defects in the film prone to adsorption of water or contaminants that can cause movable structures to adhere. These analysis methods also indicated significant variability in the coverage of lubricating molecules from one coating process to another, even for identical processing conditions. The variability was due to residual molecules left in the deposition chamber after incomplete cleaning. The coating process was modified to result in improved uniformity and total coverage. Still, a direct correlation was found between the resulting static friction behavior of MEMS interfaces, and the absolute monolayer coverage. While experimental results indicated that many devices would fail to start after aging, the modeling approach used here predicted that all the devices should start. Adhesion modeling based upon values of adhesion energy from cantilever beams is therefore inadequate. Material deposition that bridged gaps was observed in some devices, and potentially inhibits start-up more than the adhesion model indicates. Advances were made in our ability to model MEMS devices, but additional combined experimental-modeling studies will be needed to advance the work to a point of providing predictive capability. The methodology developed here should prove useful in future assessments of device aging, however. Namely, it consisted of measuring interface properties, determining how they change with time, developing a model of device behavior incorporating interface behavior, and then using the age-aware interface behavior model to predict device function

Towards Data-Driven Operational Wildfire Spread Modeling: A Report of the NSF-Funded WIFIRE Workshop

This report presents a record of the discussions that took place during the workshop entitled “Towards Data-Driven Operational Wildfire Spread Modeling” held on January 12-13, 2015, at the University of California, San Diego. The workshop was organized as part of WIFIRE, a collaborative project sponsored by the National Science Foundation (NSF) between San Diego Supercomputer Center, Calit2's Qualcomm Institute and Jacobs School of Engineering at the University of California at San Diego (UCSD) and the Department of Fire Protection Engineering at the University of Maryland (UMD). The objective of WIFIRE is to build a cyberinfrastructure for real-time and data-driven simulation, prediction and visualization of wildfire behavior (see http://wifire.ucsd.edu). WIFIRE is funded by NSF Award #1331615 as part of the Interdisciplinary Research in Hazards and Disasters (Hazards SEES) program. The objectives of the WIFIRE workshop were: (1) to identify technical barriers and milestones that need to be overcome in order to develop validated data-driven wildfire spread models and make them operational; and (2) to bring together leading representatives of the wildfire research community, the geosciences community and the fire science community. The wildfire research community has relevant expertise on wildfire operations; the geosciences community has relevant expertise on large-scale effects in wildfires (e.g., the coupling with atmospheric phenomena); the fire science community has relevant expertise on flame-scale effects in wildfires (e.g., the response of the fire to changing local conditions). The workshop was organized around four main topical areas and corresponding breakout groups, including operational rate-of-spread models for wildfire spread, CFD models, wildfire data, and data assimilation (see Appendix A for a description of the WIFIRE workshop program). Our goal in this report is to document and share the substance and scope of the workshop discussions and to thereby invite the wider research community to support, engage in, and contribute to the general effort to develop operational data-driven tools for wildfire spread predictions.The National Science Foundation via Award #1331615 as part of the Interdisciplinary Research in Hazards and Disasters (Hazards SEES) program

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy