53 research outputs found

    FEniCS-HPC: Automated predictive high-performance finite element computing with applications in aerodynamics

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    Developing multiphysics finite element methods (FEM) and scalable HPC implementations can be very challenging in terms of software complexity and performance, even more so with the addition of goal-oriented adaptive mesh refinement. To manage the complexity we in this work present general adaptive stabilized methods with automated implementation in the FEniCS-HPC automated open source software framework. This allows taking the weak form of a partial differential equation (PDE) as input in near-mathematical notation and automatically generating the low-level implementation source code and auxiliary equations and quantities necessary for the adaptivity. We demonstrate new optimal strong scaling results for the whole adaptive framework applied to turbulent flow on massively parallel architectures down to 25000 vertices per core with ca. 5000 cores with the MPI-based PETSc backend and for assembly down to 500 vertices per core with ca. 20000 cores with the PGAS-based JANPACK backend. As a demonstration of the power of the combination of the scalability together with the adaptive methodology allowing prediction of gross quantities in turbulent flow we present an application in aerodynamics of a full DLR-F11 aircraft in connection with the HiLift-PW2 benchmarking workshop with good match to experiments

    Pedestrian Road Traffic Injuries in Urban Peruvian Children and Adolescents: Case Control Analyses of Personal and Environmental Risk Factors

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    BACKGROUND: Child pedestrian road traffic injuries (RTIs) are an important cause of death and disability in poorer nations, however RTI prevention strategies in those countries largely draw upon studies conducted in wealthier countries. This research investigated personal and environmental risk factors for child pedestrian RTIs relevant to an urban, developing world setting. METHODS: This is a case control study of personal and environmental risk factors for child pedestrian RTIs in San Juan de Miraflores, Lima, Perú. The analysis of personal risk factors included 100 cases of serious pedestrian RTIs and 200 age and gender matched controls. Demographic, socioeconomic, and injury data were collected. The environmental risk factor study evaluated vehicle and pedestrian movement and infrastructure at the sites in which 40 of the above case RTIs occurred and 80 control sites. FINDINGS: After adjustment, factors associated with increased risk of child pedestrian RTIs included high vehicle volume (OR 7.88, 95%CI 1.97-31.52), absent lane demarcations (OR 6.59, 95% CI 1.65-26.26), high vehicle speed (OR 5.35, 95%CI 1.55-18.54), high street vendor density (OR 1.25, 95%CI 1.01-1.55), and more children living in the home (OR 1.25, 95%CI 1.00-1.56). Protective factors included more hours/day spent in school (OR 0.52, 95%CI 0.33-0.82) and years of family residence in the same home (OR 0.97, 95%CI 0.95-0.99). CONCLUSION: Reducing traffic volumes and speeds, limiting the number of street vendors on a given stretch of road, and improving lane demarcation should be evaluated as components of child pedestrian RTI interventions in poorer countries

    Solar Radiation Maps

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    [EN]Solar maps are very interesting tools to describe the characteristics of a region from the solar radiation point of view, and can be applied in atmospheric sciences and for energy engineering. To make them possible, a solar radiation numerical model is proposed. This one allows us to estimate radiation values on any point on earth. The model takes into account the terrain surface conditions and the cast shadows. The procedure uses 2-D adaptive triangles meshes built refining according to surface and albedo characteristics. Solar irradiance values are obtained for clear sky conditions. Using clear sky index as a conversion factor, real sky values are computed in terms of irradiance or irradiation with a desired time step. Finally, the solar radiation maps are obtained for all the domain

    Validity of instruments to assess students' travel and pedestrian safety

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    <p>Abstract</p> <p>Background</p> <p>Safe Routes to School (SRTS) programs are designed to make walking and bicycling to school safe and accessible for children. Despite their growing popularity, few validated measures exist for assessing important outcomes such as type of student transport or pedestrian safety behaviors. This research validated the SRTS school travel survey and a pedestrian safety behavior checklist.</p> <p>Methods</p> <p>Fourth grade students completed a brief written survey on how they got to school that day with set responses. Test-retest reliability was obtained 3-4 hours apart. Convergent validity of the SRTS travel survey was assessed by comparison to parents' report. For the measure of pedestrian safety behavior, 10 research assistants observed 29 students at a school intersection for completion of 8 selected pedestrian safety behaviors. Reliability was determined in two ways: correlations between the research assistants' ratings to that of the Principal Investigator (PI) and intraclass correlations (ICC) across research assistant ratings.</p> <p>Results</p> <p>The SRTS travel survey had high test-retest reliability (κ = 0.97, n = 96, p < 0.001) and convergent validity (κ = 0.87, n = 81, p < 0.001). The pedestrian safety behavior checklist had moderate reliability across research assistants' ratings (ICC = 0.48) and moderate correlation with the PI (r = 0.55, p =< 0.01). When two raters simultaneously used the instrument, the ICC increased to 0.65. Overall percent agreement (91%), sensitivity (85%) and specificity (83%) were acceptable.</p> <p>Conclusions</p> <p>These validated instruments can be used to assess SRTS programs. The pedestrian safety behavior checklist may benefit from further formative work.</p

    Differential Functional Constraints on the Evolution of Postsynaptic Density Proteins in Neocortical Laminae

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    The postsynaptic density (PSD) is a protein dense complex on the postsynaptic membrane of excitatory synapses that is implicated in normal nervous system functions such as synaptic plasticity, and also contains an enrichment of proteins involved in neuropsychiatric disorders. It has recently been reported that the genes encoding PSD proteins evolved more slowly than other genes in the human brain, but the underlying evolutionary advantage for this is not clear. Here, we show that cortical gene expression levels could explain most of this effect, indicating that expression level is a primary contributor to the evolution of these genes in the brain. Furthermore, we identify a positive correlation between the expression of PSD genes and cortical layers, with PSD genes being more highly expressed in deep layers, likely as a result of layer-enriched transcription factors. As the cortical layers of the mammalian brain have distinct functions and anatomical projections, our results indicate that the emergence of the unique six-layered mammalian cortex may have provided differential functional constraints on the evolution of PSD genes. More superficial cortical layers contain PSD genes with less constraint and these layers are primarily involved in intracortical projections, connections that may be particularly important for evolved cognitive functions. Therefore, the differential expression and evolutionary constraint of PSD genes in neocortical laminae may be critical not only for neocortical architecture but the cognitive functions that are dependent on this structure

    Coronary artery surgery in octogenarians: Evolving strategies for the improvement in early and late results

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    11nononeThe purpose of this study was to investigate retrospectively early and late outcomes of coronary artery bypass grafting (CABG) in a large series of octogenarians. We retrospectively reviewed the data of 241 octogenarian patients who underwent CABG between April 2002 and April 2009 at our institution. Mean age was 84.7 ± 1.8 years. Patients affected by concomitant coexistent organic aortic, mitral, or tricuspid valve disease were excluded from the study. Patients with functional secondary ischemic mitral incompetence were included in the study. The majority of the patients were male. Angina pectoris functional class III/IV accounted for 164 patients (68%). Left ventricular ejection fraction ≤35% was diagnosed in 38 patients (15.8%). Early mortality rate was 5.8% (14 patients). Causes of death were cardiac related in 10 patients. Preoperative independent predictors of in-hospital mortality obtained with multivariate analysis were extracardiac arteriopathy, New York Heart Association class III/IV, and previous percutaneous transluminal coronary angioplasty (PTCA). The overall mean follow-up was 41.6 ± 25.9 months (range 1-87.6 months). Among the 222 contacted survivors, there were 16 (7.2%) deaths during the follow-up. The actuarial survival was 91.9% at 1 year and 83.5% at 5 years. On multivariate analysis, time to late death was adversely affected by preoperative extracardiac arteriopathy and previous PTCA. Advanced age alone should not be a deterrent for CABG if it has been determined that the benefits outweigh the potential risk. A careful selection of optimal candidates, based on the evaluation of their systemic comorbidities, appears mandatory in order to obtain the greatest benefit for these high-risk patients. © 2011 Springer.Nicolini, Francesco; Molardi, Alberto; Verdichizzo, Danilo; Gallazzi, Maria Cristina; Spaggiari, Igino; Cocconcelli, Flavio; Budillon, Alessandro Maria; Borrello, Bruno; Rivara, Davide; Beghi, Cesare; Gherli, TizianoNicolini, Francesco; Molardi, Alberto; Verdichizzo, Danilo; Gallazzi, Maria Cristina; Spaggiari, Igino; Cocconcelli, Flavio; Budillon, Alessandro Maria; Borrello, Bruno; Rivara, Davide; Beghi, Cesare; Gherli, Tizian
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