802 research outputs found

    Evaluation of Skin Cancer Care: Integrating different perspectives

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    Reducing unnecessary follow-up visits after low-risk basal cell carcinoma. From identification, to exploration by means of quantitative research. After quantification of these results, a personalized letter for patients was determined the best strategy to reduce the unnecessary care. This was tested in practice and resulted in a decrease in the number of control visits

    Some remarks on the spectral functions of the Abelian Higgs Model

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    We consider the unitary Abelian Higgs model and investigate its spectral functions at one-loop order. This analysis allows to disentangle what is physical and what is not at the level of the elementary particle propagators, in conjunction with the Nielsen identities. We highlight the role of the tadpole graphs and the gauge choices to get sensible results. We also introduce an Abelian Curci-Ferrari action coupled to a scalar field to model a massive photon which, like the non-Abelian Curci-Ferarri model, is left invariant by a modified non-nilpotent BRST symmetry. We clearly illustrate its non-unitary nature directly from the spectral function viewpoint. This provides a functional analogue of the Ojima observation in the canonical formalism: there are ghost states with nonzero norm in the BRST-invariant states of the Curci-Ferrari model.Comment: 32 pages, 12 figure

    The influence of a six degrees of freedom couch and an individual head support in patient positioning in radiotherapy of head and neck cancer

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    Reproducible patient positioning is important in radiotherapy (RT) of head-and-neck cancer. We therefore compared set-up errors in head-and-neck RT resulting from three different patient positioning systems. Patients were either treated with a standard head support (SHS) and conventional treatment couch (SHS-3, n = 10), a SHS and rotational couch (SHS-6, n = 10), or an individual head support (IHS) and rotational couch (IHS-6, n = 10). Interfraction mean translation vector lenghts were significantly lower for IHS-6 compared to SHS-3 (0.8 ± 0.3 mm vs. 1.4 ± 0.7 mm, P = 0.001). Intrafraction displacement was comparable among cohorts. This study showed that the use of a six degrees of freedom couch combined with an IHS in head-and-neck RT resulted in better interfraction reproducibilit

    Towards sustainable infrastructure development in Africa : design principles and strategies for lifespan-based building performance

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    Societies and economies the world over develop on the wheels of infrastructure. In Africa, it accounts for about one-third to one-half of all public investment (Kessides, 1993). Significant about infrastructure in general, however is the fact that they have very long lives. Consequently, their impact on capital investment, resource utilization, the quality of the environment and overall quality of human life can be very significant. It is important therefore that they meet performance requirements in terms of economic, ecological and social sustainability. By the same token, their long lifespan fraught the design task with enormous amount of uncertainties, compounding the already ill-defined nature of design problems. Given that change is importune, and the fact that it is impracticable to foresee all the changes that will occur over time, a defining characteristic of all infrastructure will be the capacity to respond to change. Focusing on the case of buildings, this paper presents a discussion on some design principles and strategies which assure responsiveness to change and hence sustainable performance. Although the concepts have been advocated for over half a century now, studies show that they still remain marginal to the design profession. To clarify the concepts for research questioning and extension of knowledge, this paper seeks to examine their basic tenets with the view to harmonize the core principles and strategies. A literature review method is used with examples from field observations where necessary. The paper first attempts to review and harmonize these principles, and highlights the practical usefulness. It then highlights the implications for research and development in building technology as well as technology capacity building for sustainable infrastructure development in Africa
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