6,989 research outputs found

    Area contraction for harmonic automorphisms of the disk

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    A harmonic self-homeomorphism of a disk does not increase the area of any concentric disk.Comment: 7 page

    Existence of energy-minimal diffeomorphisms between doubly connected domains

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    The paper establishes the existence of homeomorphisms between two planar domains that minimize the Dirichlet energy. Specifically, among all homeomorphisms f : R -> R* between bounded doubly connected domains such that Mod (R) < Mod (R*) there exists, unique up to conformal authomorphisms of R, an energy-minimal diffeomorphism. No boundary conditions are imposed on f. Although any energy-minimal diffeomorphism is harmonic, our results underline the major difference between the existence of harmonic diffeomorphisms and the existence of the energy-minimal diffeomorphisms. The existence of globally invertible energy-minimal mappings is of primary pursuit in the mathematical models of nonlinear elasticity and is also of interest in computer graphics.Comment: 34 pages, no figure

    Evidence Based Eye Care

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    A summary of the results from numerous randomized clinical trials in eye care for students and clinicians

    Nonclassical rotational behavior at the vicinity of the lamda point

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    The rotational property of a quantum liquid at the vicinity of the lambda point is examined. In a liquid helium 4 just above the lambda point, under the strong influence of Bose statistics, the coherent many-body wave function grows to an intermediate size between a macroscopic and a microscopic one, which is of a different nature from the thermal fluctuations. It must reflect in the rotational properties such as the moment of inertia. Beginning with the bosons without the condensate, we make a perturbation calculation of its susceptibility with respect to the repulsive interaction, and examine how, with decreasing temperature, the growth of the coherent wave function gradually changes the rotational behavior of a liquid:The moment of inertia slightly decreases just above the lambda point. This means that at the vicinity of the lambda point, the mechanical superfluid density does not always agree with the thermodynamical one.We compare the result to the experiment by Hess and Fairbank. A new interpretation of the shear viscosity just above the lambda point is given from this viewpoint.Comment: 12pages, 5figure

    Ophthalmic Drugs 2015

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    A handy reference about ophthalmic drugs for students and clinicians in eye care profession

    Assessing the language of chat for teamwork dialogue

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    In technology enhanced language learning, many pedagogical activities involve students in online discussion such as synchronous chat, in order to help them practice their language skills. Besides developing the language competency of students, it is also crucial to nurture their teamwork competencies for today's global and complex environment. Language communication is an important glue of teamwork. In order to assess the language of chat for teamwork dimensions, several text mining methods are pos sible. However, difficulties arise such as pre-processing being a black box and classification approaches and algorithms being dependent on the context. To address these issues, the study will evaluate and explain preprocessing and classification methods used to analyze teamwork dialogue from a dataset of chat data. Analytics methods evaluated in this study provide a direction for assessing the language of chat for teamwork dialogue and can help extend the work of technology enhanced language learning to n ot only focus on academic competency, but on the communication aspect too

    Failure analysis of a steel motorcycle kickstand

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    Copyright @ 2009 Springer US.A fractured steel motorcycle kickstand was metallurgically investigated using a range of failure analysis tools [visual examination, energy dispersive X-ray (EDX) analysis, electron microprobe analysis (EPMA), scanning electron microscopy (SEM), fractography, optical microscopy, hardness testing and non-destructive testing (NDT)]. The steel kickstand’s composition, its microstructure, electron fractographs, and mechanical test results have been critically interpreted. Some evidence of wear damage, in the failed kickstand, was observed. The microstructural and fractographic analyses showed pre-existing micro-cracks which were believed to have grown to result in ductile failure followed by acceleration of corrosion. Recommendations have been made to avoid the failure of the motorcycle kickstand
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