2 research outputs found
Polygonal finite element method for nonlinear constitutive modeling of polycrystalline ferroelectrics
No full textIn meso-mechanistic analyses, crystal grains are often idealized as polygons. Presuming that each grain possesses its own unique and uniform crystallographic structure, it is highly desirable to model a grain by only one basic computational sub-domain. To this end, polygonal finite element models are developed for constitutive modeling of polycrystalline ferroelectrics. The success of these models relies on a hybrid electromechanical variational principle with equilibrating assumed electromechanical stress (stress+electricdisplacement). To construct the element electromechanical stiffness matrix, only piecewise boundary interpolations of the electromechanical displacement (displacement+nodalelectricpotential) are required. Higher-order elements are made available by inserting side-nodes along the element edges and enriching the electromechanical stress. By incorporating an energy-based nonlinear constitutive model, characteristic features in electric saturation and domain switching are successfully reproduced in the finite element simulation. The effect of microcracking on the macroscropic response of ferroelectrics is also studied. © 2005 Elsevier B.V. All rights reserved.link_to_subscribed_fulltex
Explaining variation in cancer survival between 11 jurisdictions in the International Cancer Benchmarking Partnership: a primary care vignette survey.
No full textOBJECTIVES: The International Cancer Benchmarking Partnership (ICBP) is a collaboration between 6 countries and 12 jurisdictions with similar primary care-led health services. This study investigates primary care physician (PCP) behaviour and systems that may contribute to the timeliness of investigating for cancer and subsequently, international survival differences. DESIGN: A validated survey administered to PCPs via the internet set out in two parts: direct questions on primary care structure and practice relating to cancer diagnosis, and clinical vignettes, assessing management of scenarios relating to the diagnosis of lung, colorectal or ovarian cancer. PARTICIPANTS: 2795 PCPs in 11 jurisdictions: New South Wales and Victoria (Australia), British Columbia, Manitoba, Ontario (Canada), England, Northern Ireland, Wales (UK), Denmark, Norway and Sweden. PRIMARY AND SECONDARY OUTCOME MEASURES: Analysis compared the cumulative proportion of PCPs in each jurisdiction opting to investigate or refer at each phase for each vignette with 1-year survival, and conditional 5-year survival rates for the relevant cancer and jurisdiction. Logistic regression was used to explore whether PCP characteristics or system differences in each jurisdiction affected the readiness to investigate. RESULTS: 4 of 5 vignettes showed a statistically significant correlation (p<0.05 or better) between readiness to investigate or refer to secondary care at the first phase of each vignette and cancer survival rates for that jurisdiction. No consistent associations were found between readiness to investigate and selected PCP demographics, practice or health system variables. CONCLUSIONS: We demonstrate a correlation between the readiness of PCPs to investigate symptoms indicative of cancer and cancer survival rates, one of the first possible explanations for the variation in cancer survival between ICBP countries. No specific health system features consistently explained these findings. Some jurisdictions may consider lowering thresholds for PCPs to investigate for cancer-either directly, or by specialist referral, to improve outcomes
