10,344 research outputs found

    Taking reasonable pluralism seriously: an internal critique of political liberalism

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    The later Rawls attempts to offer a non-comprehensive, but nonetheless moral justification in political philosophy. Many critics of political liberalism doubt that this is successful, but Rawlsians often complain that such criticisms rely on the unwarranted assumption that one cannot offer a moral justification other than by taking a philosophically comprehensive route. In this article, I internally criticize the justification strategy employed by the later Rawls. I show that he cannot offer us good grounds for the rational hope that citizens will assign political values priority over non-political values in cases of conflict about political matters. I also suggest an alternative approach to justification in political philosophy (that is, a weak realist, Williams-inspired account) that better respects the later Rawls’s concern with non-comprehensiveness and pluralism than either his own view or more comprehensive approaches. Thus, if we take reasonable pluralism seriously, then we should adopt what Shklar aptly called ‘liberalism of fear’. </jats:p

    Hydraulic Behaviour of He II in Stratified Counter-Current Two-Phase Flow

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    Future large devices using superconducting magnets or RF cavities (e.g. LHC or TESLA) need He II two-phase flow for cooling. The research carried out into counter-current superfluid two-phase flow was the continuation of work on co-current flow and benefited from all the knowledge acquired both experimentally and theoretically. Experiments were conducted on two different pipe diameters (40 and 65 m m I.D. tube) for slopes ranging between 0 and 2%, and for temperatures ranging between 1.8 and 2 K. This paper introduces the theoretical model, describes the tests, and provides a critical review of the results obtained in He II counter current two-phase flow

    On the Hausdorff volume in sub-Riemannian geometry

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    For a regular sub-Riemannian manifold we study the Radon-Nikodym derivative of the spherical Hausdorff measure with respect to a smooth volume. We prove that this is the volume of the unit ball in the nilpotent approximation and it is always a continuous function. We then prove that up to dimension 4 it is smooth, while starting from dimension 5, in corank 1 case, it is C^3 (and C^4 on every smooth curve) but in general not C^5. These results answer to a question addressed by Montgomery about the relation between two intrinsic volumes that can be defined in a sub-Riemannian manifold, namely the Popp and the Hausdorff volume. If the nilpotent approximation depends on the point (that may happen starting from dimension 5), then they are not proportional, in general.Comment: Accepted on Calculus and Variations and PD

    Nonlinear software sensor for monitoring genetic regulation processes with noise and modeling errors

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    Nonlinear control techniques by means of a software sensor that are commonly used in chemical engineering could be also applied to genetic regulation processes. We provide here a realistic formulation of this procedure by introducing an additive white Gaussian noise, which is usually found in experimental data. Besides, we include model errors, meaning that we assume we do not know the nonlinear regulation function of the process. In order to illustrate this procedure, we employ the Goodwin dynamics of the concentrations [B.C. Goodwin, Temporal Oscillations in Cells, (Academic Press, New York, 1963)] in the simple form recently applied to single gene systems and some operon cases [H. De Jong, J. Comp. Biol. 9, 67 (2002)], which involves the dynamics of the mRNA, given protein, and metabolite concentrations. Further, we present results for a three gene case in co-regulated sets of transcription units as they occur in prokaryotes. However, instead of considering their full dynamics, we use only the data of the metabolites and a designed software sensor. We also show, more generally, that it is possible to rebuild the complete set of nonmeasured concentrations despite the uncertainties in the regulation function or, even more, in the case of not knowing the mRNA dynamics. In addition, the rebuilding of concentrations is not affected by the perturbation due to the additive white Gaussian noise and also we managed to filter the noisy output of the biological systemComment: 21 pages, 7 figures; also selected in vjbio of August 2005; this version corrects a misorder in the last three references of the published versio

    Evidence for spin liquid ground state in SrDy2_2O4_4 frustrated magnet probed by muSR

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    Muon spin relaxation (μ\muSR) measurements were carried out on SrDy2_2O4_4, a frustrated magnet featuring short range magnetic correlations at low temperatures. Zero-field muon spin depolarization measurements demonstrate that fast magnetic fluctuations are present from T=300T=300 K down to 20 mK. The coexistence of short range magnetic correlations and fluctuations at T=20T=20 mK indicates that SrDy2_2O4_4 features a spin liquid ground state. Large longitudinal fields affect weakly the muon spin depolarization, also suggesting the presence of fast fluctuations. For a longitudinal field of μ0H=2\mu_0H=2 T, a non-relaxing asymmetry contribution appears below T=6T=6 K, indicating considerable slowing down of the magnetic fluctuations as field-induced magnetically-ordered phases are approached.Comment: 6 pages, 4 figures, to be published as a proceeding of HFM2016 in Journal of Physics: Conference Series (JPCS

    Distance dependence of force and dissipation in non-contact atomic force microscopy on Cu(100) and Al(111)

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    The dynamic characteristics of a tip oscillating in the nc-AFM mode in close vicinity to a Cu(100)-surface are investigated by means of phase variation experiments in the constant amplitude mode. The change of the quality factor upon approaching the surface deduced from both frequency shift and excitation versus phase curves yield to consistent values. The optimum phase is found to be independent of distance. The dependence of the quality factor on distance is related to 'true' damping, because artefacts related to phase misadjustment can be excluded. The experimental results, as well as on-resonance measurements at different bias voltages on an Al(111) surface, are compared to Joule dissipation and to a model of dissipation in which long-range forces lead to viscoelastic deformations

    Segregation and ordering at the (1×2) reconstructed Pt80Fe20(110) surface determined by low-energy electron diffraction

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    The surface of an ordered Pt80Fe20(110) crystal exhibits (1×2) and (1×3) reconstructions depending on the annealing treatment after ion bombardment. The (1×3) structure occurs after annealing in the range 750 to 900 K. Annealing above 1000 K leads to the (1×2) structure, which is, from the present result, unambiguously attributed to the same geometrical reconstruction as Pt(110) but with smaller relaxation amplitudes: a detailed low-energy electron-diffraction analysis concludes to a missing-row structure with row pairing in layers 2 and 4 accompanied by a buckling in layers 3 and 5. The top layer spacing is contracted by 13%, and further relaxations are detectable down to the fifth layer. The specific diffraction spots associated with the bulk chemical ordering along the dense [1¯10] rows are very weak: The I(V) analysis shows that this chemical ordering is absent in the outermost ‘‘visible’’ rows but gradually recovers over five to six layers deep. General Pt enrichment is found in the surface ‘‘visible’’ rows (in layers 1–3), but segregation and order yield a subtle redistribution of Pt and Fe atoms in deeper rows: For example, in layer 2, the visible row is Pt rich, whereas the other row (buried under layer 1) is enriched with Fe. Because of the many parameters considered, a fit procedure was applied to a large data basis to solve the structure; the results were confirmed and illustrated subsequently by a standard I(V) analysis for the most relevant parameters. The final r factors are RDE=0.36, RP=0.34, and RZJ=0.14 for two beam sets at normal and oblique incidence consisting of 26 and 21 beams, respectively

    Entire curves avoiding given sets in C^n

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    Let FCnF\subset\Bbb C^n be a proper closed subset of Cn\Bbb C^n and ACnFA\subset\Bbb C^n\setminus F at most countable (n2n\geq 2). We give conditions of FF and AA, under which there exists a holomorphic immersion (or a proper holomorphic embedding) ϕ:CCn\phi:\Bbb C\to\Bbb C^n with Aϕ(C)CnFA\subset\phi(\Bbb C)\subset\Bbb C^n\setminus F.Comment: 10 page
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