70 research outputs found

    A fast solver for systems of reaction-diffusion equations

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    In this paper we present a fast algorithm for the numerical solution of systems of reaction-diffusion equations, ∂tu+a⋅∇u=Δu+F(x,t,u)\partial_t u + a \cdot \nabla u = \Delta u + F (x, t, u), x∈Ω⊂R3x \in \Omega \subset \mathbf{R}^3, t>0t > 0. Here, uu is a vector-valued function, u≡u(x,t)∈Rmu \equiv u(x, t) \in \mathbf{R}^m, mm is large, and the corresponding system of ODEs, ∂tu=F(x,t,u)\partial_t u = F(x, t, u), is stiff. Typical examples arise in air pollution studies, where aa is the given wind field and the nonlinear function FF models the atmospheric chemistry.Comment: 8 pages, 3 figures, to appear in Proc. 13th Domain Decomposition Conference, Lyon, October 200

    Report of the Implementation of Work Package 6 "Implementation of Methodology" in the Framework of the IRNet Project

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    This article, prepared by an international team of researchers from different scientific areas connected with ICT, e-learning, pedagogy, and other related disciplines, focuses on the objectives and some results of the international project IRNet (www.irnet.us.edu.pl). In particular, the article describes research tools, methods, and a procedure of the Work Package 6 “Implementation of Methodology,” that is, objectives, tasks, deliverables, publications, and implementation of research trips in the context of the next stages and Work Packages of IRNet project – International Research Network

    Electron paramagnetic resonance (EPR) in medical dosimetry

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    This paper describes the fundamentals of electron paramagnetic resonance (EPR) and its application to retrospective measurements of clinically significant doses of ionizing radiation. X-band is the most widely used in EPR dosimetry because it represents a good compromise between sensitivity, sample size and water content in the sample. Higher frequency bands (e.g., W and Q) provide higher sensitivity, but they are also greatly influenced by water content. L and S bands can be used for EPR measurements in samples with high water content but they are less sensitive than X-band. Quality control for therapeutic radiation facilities using X-band EPR spectrometry of alanine is also presented

    Retrospective Assessment of Exposures to Ionising Radiation.

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    The impact of diet switching on resource allocation to reproduction and longevity in Mediterranean fruitflies.

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    Understanding the factors that determine the allocation and utilization of organism resources may provide an insight into the mechanisms of adaptation, ageing and reproduction. Resource allocation, which is regarded as a method of adaptation, increases fitness and is genetically controlled. Experiments with variable diet feeding of female Mediterranean fruitflies (Ceratitis capitata) demonstrated that the feeding regime dramatically influences lifespan, mortality and the reproduction of flies. An analysis of experimental data and numerical experiments reveals that resource allocation could explain lifespan increase when females are switched from a sugar-only to a protein-containing diet. The heterogeneity of the initial female cohort in terms of the total amount of resources and its allocation to the processes of maintenance and reproduction plays a significant role in this
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