58 research outputs found

    Microscopic/stochastic timesteppers and coarse control: a kinetic Monte Carlo example

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    Coarse timesteppers provide a bridge between microscopic / stochastic system descriptions and macroscopic tasks such as coarse stability/bifurcation computations. Exploiting this computational enabling technology, we present a framework for designing observers and controllers based on microscopic simulations, that can be used for their coarse control. The proposed methodology provides a bridge between traditional numerical analysis and control theory on the one hand and microscopic simulation on the other

    Feasibility randomised controlled trial of a guided workbook intervention to support work-related goals among cancer survivors in the UK

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    Objectives: Employment following illness is associated with better physical and psychological functioning. This study aimed to assess the feasibility and acceptability of a theoretically led workbook intervention designed to support patients with cancer returning to work. Design: Parallel-group randomised controlled trial with embedded qualitative interviews. Setting: Oncology clinics within four English National Health Service Trusts. Participants: Patients who had received a diagnosis of breast, gynaecological, prostate or colorectal cancer and who had been receiving treatment for a minimum of two weeks. Intervention: A self-guided WorkPlan workbook designed to support patients with cancer to return to work with fortnightly telephone support calls to discuss progress. The control group received treatment as usual and was offered the workbook at the end of their 12-month follow-up. Outcome measures: We assessed aspects of feasibility including eligibility, recruitment, data collection, attrition, feasibility of the methodology, acceptability of the intervention and potential to calculate cost-effectiveness. Results: The recruitment rate of eligible patients was 44%; 68 participants consented and 58 (85%) completed baseline measures. Randomisation procedures were acceptable, data collection methods (including cost-effectiveness data) were feasible and the intervention was acceptable to participants. Retention rates at 6-month and 12-month follow-up were 72% and 69%, respectively. At 6-month follow-up, 30% of the usual care group had returned to full-time or part-time work (including phased return to work) compared with 43% of the intervention group. At 12 months, the percentages were 47% (usual care) and 68% (intervention). Conclusions: The findings confirm the feasibility of a definitive trial, although further consideration needs to be given to increasing the participation rates among men and black and ethnic minority patients diagnosed with cancer

    A feasibility randomized controlled trial of a guided workbook intervention to support work-related goals among cancer survivors in the UK

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    Objectives: Employment following illness is associated with better physical and psychological functioning. This study aimed to assess the feasibility and acceptability of a theoretically-led workbook intervention designed to support cancer patients returning to work. Design: Parallel-group randomized controlled trial with embedded qualitative interviews Setting: Oncology clinics within four English National Health Service Trusts Participants: Patients who had received a diagnosis of breast, gynecological, prostate or colorectal cancer and who were at least 2 weeks post-treatment initiation. Intervention: A self-guided WorkPlan workbook designed to support cancer patients to return to work with fortnightly telephone support calls to discuss progress. The control group received treatment as usual, and were offered the workbook at the end of their 12-month follow-up. Outcome measures: We assessed aspects of feasibility including eligibility, recruitment, data collection, attrition, feasibility of the methodology, acceptability of the intervention and potential to calculate cost-effectiveness. Results: The recruitment rate of eligible patients was 44%; 68 participants consented and 58 (85%) completed baseline measures. Randomization procedures were acceptable, data collection methods (including cost-effectiveness data) were feasible and the intervention was acceptable to participants. Retention rates at six and 12 months follow-up were 72% and 69% respectively. At 6-month follow-up 30% of the usual care group had returned to full or part-time work (including phased return to work) compared to 43% of the intervention group. At 12-months the percentages were 47% (usual care) and 68% (intervention). Conclusions: The findings confirm the feasibility of a definitive trial, although further consideration needs to be given to increasing the participation rates among men and Black and ethnic minority patients diagnosed with cancer

    Prevalence of BRCA1 and BRCA2 mutations in unselected breast cancer patients from Greece

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    <p>Abstract</p> <p>Background</p> <p>Inheritance of a mutation in either <it>BRCA1 </it>or <it>BRCA2 </it>accounts for approximately 5% of all breast cancer cases, but varies by country. Investigations into the contribution of <it>BRCA </it>mutations to breast cancer incidence in Greece have been, for the most part, limited by small sample sizes and by the use of cases selected for their family history of cancer. The aim of the current study was to estimate <it>BRCA </it>mutation frequencies in breast cancer patients unselected for family history.</p> <p>Methods</p> <p>To do so, we enrolled 127 unselected women with breast cancer from the Alexandra Hospital in Athens, Greece, a large public hospital in the city. Mutations in <it>BRCA1 </it>and <it>BRCA2 </it>were detected using a combination of techniques and were confirmed by direct sequencing. Two large genomic deletions were sought using mutation-specific assays. A detailed family history of cancer was obtained from each patient.</p> <p>Results</p> <p>We were able to successfully complete testing on samples from 127 women. Among these, six mutations were identified (four in <it>BRCA1 </it>and two in <it>BRCA2</it>) representing 4.7% of the total or 9.5% of cases diagnosed before age forty. None of the mutation carriers had a family history of breast or ovarian cancer. Three of the four <it>BRCA1 </it>mutations were in exon 20: two were a G5331A mutation and the third was a 3.2 kb deletion. The fourth <it>BRCA1 </it>mutation was the 3819delGTAAA in exon 11. The two <it>BRCA2 </it>mutations were in exon 11 (3782del10 and 4512insT).</p> <p>Conclusions</p> <p>The G5331A mutation in <it>BRCA1 </it>appears to be a founder mutation in the Greek population.</p

    Discrete population balance models of random agglomeration and cleavage in polymer pyrolysis

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    The processes of random agglomeration and cleavage (both of which are important for the development of new models of polymer combustion, but are also applicable in a wide range of fields including atmospheric physics, radiation modelling and astrophysics) are analysed using population balance methods. The evolution of a discrete distribution of particles is considered within this framework, resulting in a set of ordinary differential equations for the individual particle concentrations. Exact solutions for these equations are derived, together with moment generating functions. Application of the discrete Laplace transform (analogous to the Z-transform) is found to be effective in these problems, providing both exact solutions for particle concentrations and moment generating functions. The combined agglomeration-cleavage problem is also considered. Unfortunately, it has been impossible to find an exact solution for the full problem, but a stable steady state has been identified and computed

    Cancer Survivors’ Social Context in the Return to Work Process:Narrative Accounts of Social Support and Social Comparison Information

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    Purpose: Returning to work is a process that is intertwined with the social aspects of one’s life, which can influence the way in which that person manages their return to work and also determines the support available to them. This study aimed to explore cancer patients’ perceptions of the role of their social context in relation to returning to work following treatment. Methods: Twenty-three patients who had received a diagnosis of either urological, breast, gynaecological, or bowel cancer participated in semi-structured interviews examining general perceptions of cancer, work values and perceptions of the potential impact of their cancer diagnosis and treatment on work. Interviews were analysed using the iterative process of Framework Analysis. Results: Two superordinate themes emerged as influential in the return to work process: Social support as a facilitator of return to work (e.g. co-workers’ support and support outside of the workplace) and Social comparison as an appraisal of readiness to return to work (e.g. comparisons with other cancer patients, colleagues, and employees in other organisations or professions). Conclusions: Two functions of the social context of returning to work after cancer were apparent in the participants’ narrative: the importance of social support as a facilitator of returning to work and the utilisation of social comparison information in order to appraise one’s readiness to return to work. The role of social context in returning to work has largely been absent from the research literature to date. The findings of this study suggest that social support and social comparison mechanisms may have a significant impact on an individual’s successful return to the workplace

    Finite-Dimensional Control of Nonlinear Parabolic Pde Systems With Time-Dependent Spatial Domains Using Empirical Eigenfunctions

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    This article presents a methodology for the synthesis of finite-dimensional nonlinear output feedback controllers for nonlinear parabolic partial differential equation (PDE) systems with time-dependent spatial domains. Initially, the nonlinear parabolic PDE system is expressed with respect to an appropriate time-invariant spatial coordinate, and a representative (with respect to different initial conditions and input perturbations) ensemble of solutions of the resulting time-varying PDE system is constructed by computing and solving a high-order discretization of the PDE. Then, the Karhunen-Loeve expansion is directly applied to the ensemble of solutions to derive a small set of empirical eigenfunctions (dominant spatial patterns) that capture almost all the energy of the ensemble of solutions. The empirical eigenfunctions are subsequently used as basis functions within a Galerkin model reduction framework to derive low-order ordinary differential equation (ODE) systems that accurately describe the dominant dynamics of the PDE system. The ODE systems are subsequently used for the synthesis of nonlinear output feedback controllers using geometric control methods. The proposed control method is used to stabilize an unstable steady-state of a diffusion-reaction process with nonlinearities, spatially-varying coefficients and time-dependent spatial domain, and is shown to lead to the construction of accurate low-order models and the synthesis of low-order controllers. The performance of the low-order models and controllers is successfully tested through computer simulations
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