963 research outputs found
Ethics, organ donation and tax: a proposal
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
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
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
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
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
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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