963 research outputs found

    Ethics, organ donation and tax: a proposal

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    Five arguments are presented in favour of the proposal that people who opt in as organ donors should receive a tax break. These arguments appeal to welfare, autonomy, fairness, distributive justice and self-ownership, respectively. Eight worries about the proposal are considered in this paper. These objections focus upon no-effect and counter-productiveness, the Titmuss concern about social meaning, exploitation of the poor, commodification, inequality and unequal status, the notion that there are better alternatives, unacceptable expense, and concerns about the veto of relatives. The paper argues that none of the objections to the proposal is very telling

    Discrete-event simulation unmasks the quantum Cheshire Cat

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    It is shown that discrete-event simulation accurately reproduces the experimental data of a single-neutron interferometry experiment [T. Denkmayr {\sl et al.}, Nat. Commun. 5, 4492 (2014)] and provides a logically consistent, paradox-free, cause-and-effect explanation of the quantum Cheshire cat effect without invoking the notion that the neutron and its magnetic moment separate. Describing the experimental neutron data using weak-measurement theory is shown to be useless for unravelling the quantum Cheshire cat effect

    Real-time monitoring of stress evolution during thin film growth by in situ substrate curvature measurement

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    Strain engineering is the art of inducing controlled lattice distortions in a material to modify specific physicochemical properties. Strain engineering is applied for basic fundamental studies of physics and chemistry of solids but also for device fabrication through the development of materials with new functionalities. Thin films are one of the most important tools for strain engineering. Thin films can in fact develop large strain due to the crystalline constrains at the interface with the substrate and/or as the result of specific morphological features that can be selected by an appropriate tuning of the deposition parameters. Within this context, the in situ measurement of the substrate curvature is a powerful diagnostic tool allowing a real time monitoring of the stress state of the growing film. This manuscript reviews a few recent applications of this technique and presents new measurements that point out the great potentials of the substrate curvature measurement in strain engineering. Our study also shows how, due to the high sensitivity of the technique, the correct interpretation of the results can be in certain cases not trivial and require complementary characterizations and an accurate knowledge of the physicochemical properties of the materials under investigation

    Topological tunneling with Dynamical overlap fermions

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    Tunneling between different topological sectors with dynamical chiral fermions is difficult because of a poor mass scaling of the pseudo-fermion estimate of the determinant. For small fermion masses it is virtually impossible using standard methods. However, by projecting out the small Wilson eigenvectors from the overlap operator, and treating the correction determinant exactly, we can significantly increase the rate of topological sector tunneling and reduce substantially the auto-correlation time. We present and compare a number of different approaches, and advocate a method which allows topological tunneling even at low mass with little addition to the computational cost.Comment: 17 pages; v2 as accepted in computer Physics Communication

    FFT for the APE Parallel Computer

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    We present a parallel FFT algorithm for SIMD systems following the `Transpose Algorithm' approach. The method is based on the assignment of the data field onto a 1-dimensional ring of systolic cells. The systolic array can be universally mapped onto any parallel system. In particular for systems with next-neighbour connectivity our method has the potential to improve the efficiency of matrix transposition by use of hyper-systolic communication. We have realized a scalable parallel FFT on the APE100/Quadrics massively parallel computer, where our implementation is part of a 2-dimensional hydrodynamics code for turbulence studies. A possible generalization to 4-dimensional FFT is presented, having in mind QCD applications.Comment: 17 pages, 13 figures, figures include

    Anatomy of String Breaking in QCD

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    We investigate the string breaking mechanism in n_f=2 QCD. We discuss the lattice techniques used and present results on energy levels and mixing angle of the static BBbar|QbarQ two-state system. The string breaking is visualized, by means of an animation of the action density distribution as a function of the static colour source-antisource separation.Comment: Talk presented at Lattice 2005 (Topology and Confinement), Dublin, July 25-30, 2005; 6 pages, 5 figures, 2 mpeg animations not included because of file size problems but href linked, uses PoS.cls; to appear in Proceedings of Scienc
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