7,725 research outputs found

    Full agreement and the provision of threshold public goods

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    We report threshold public good experiments in which group members not only need to be individually willing to contribute enough to provide the public good but also have to agree with each other on what every group members should contribute. We find strong support to the hypothesis that full agreement increases successful provision, although it takes a few repetitions before group members can successfully coordinate. This is consistent with our theoretical results that full agreement works because it increases criticality of each individual decision. The existence of a focal point makes it possible for the group members to successfully coordinate.Public good, threshold, full agreement, focal point, experiment, coordination

    Threshold public good games and impulse balance theory

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    We propose and develop a model of behavior in threshold public good games. The model draws on learning direction theory and impulse balance theory. We find good support for the model and demonstrate that it can explain the success rates observed in threshold public good experiments. The model is applied in a variety of dierent settings : we compare games with a full refund to those with no refund, consider changes in relative endowment, and consider changes in the step return and net reward.Public good, threshold, learning direction theory, impulse balance theory, counterfactual thinking

    Judges, public authorities and EU soft law in Italy - How you cannot tell a book by its cover

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    This chapter aims at analysing how the administrative and judicial branch deals with EU soft law in Italy. The study will summarize the findings of the interviews and case-law analyses conducted in the four policy fields taken into account by the proposed book, i.e. financial policy, environment, competition and social policy. In particular, the chapter will examine which legal and practical effects are given to European soft law by Italian administrations and judges, and whether there is a degree of consistency across different policy fields or, conversely, every sector generates different practices both by administrative authorities and courts. The reasons for the underlying differences will be examined, and specifically whether the different types of soft law play a role in the legal effects which they are granted by administrative and judicial authorities. Furthermore, the chapter will discuss whether Italy, a legal system which traditionally is not used to soft law, is changing its attitude vis-à-vis this kind of acts when their source is in EU law. Finally, the chapter will discuss whether the overwhelming production of soft law by European authorities generated problems of legal consistency with general principles of law, such as legal certainty, transparency, distribution of powers between national and European institutions

    A simple abstraction of arrays and maps by program translation

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    We present an approach for the static analysis of programs handling arrays, with a Galois connection between the semantics of the array program and semantics of purely scalar operations. The simplest way to implement it is by automatic, syntactic transformation of the array program into a scalar program followed analysis of the scalar program with any static analysis technique (abstract interpretation, acceleration, predicate abstraction,.. .). The scalars invariants thus obtained are translated back onto the original program as universally quantified array invariants. We illustrate our approach on a variety of examples, leading to the " Dutch flag " algorithm

    Why Collect Science?

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    In this critical assessment of the ‘museology of science’ I cherry-pick recent scholarship and practice to unpack the functions of science collections. Some practices (exhibition, engagement, study) have already attracted considerable attention, others not yet (storage); but all tend to be considered separately as case studies from particular institutions and for particular disciplinary audiences. Juxtaposing different reasons to collect reveals both the tensions inherent in science collections and the opportunities these collections afford, especially around their materiality. This is why we have collected science, and why we should continue

    Coherent transport of atomic wave packets in amplitude-modulated vertical optical lattices

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    We report on the realization of dynamical control of transport for ultra-cold Sr88 atoms loaded in an accelerated and amplitude-modulated 1D optical lattice. We tailor the energy dispersion of traveling wave packets and reversibly switch between Wannier-Stark localization and driven transport based on coherent tunneling. Within a Loschmidt-echo scheme where the atomic group velocities are reversed at once, we demonstrate a novel mirror for matter waves working independently of the momentum state and discuss possible applications to force measurements at micrometric scales

    Gas-graft coverage after DMEK: A clinically validated numeric study

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    Purpose: We investigate the influence of positioning, gas fill, and anterior chamber size on bubble configuration and graft coverage after Descemet\u2019s membrane endothelial keratoplasty (DMEK). Methods: We use a mathematical model to study the bubble shape and graft coverage in eyes of varying anterior chamber depths (ACD). The governing equations are solved numericly using the open source software OpenFOAM. Numeric results are validated clinically so that clinical gas fill measures can be correlated with numeric results providing gas-graft coverage information otherwise clinically inaccessible. Results: In a phakic eye (ACD = 2.65 mm) with a gas fill of 35%, graft contact ranged from 35% to 38% depending on positioning and increased to 85% to 92% with a 70% fill. In contrast, positioning of a pseudophakic eye (ACD = 4.35) with a gas fill of 35% results in graft contact ranging from 8% to 52%, increasing to 63% to 94% with a 70% fill. The mathematical model demonstrates negligible differences between air and SF6 results and interestingly, a very thin central patch of aqueous humor within the gas bubble is found in some cases. Conclusions: Graft coverage in phakic eyes (ACD 64 3 mm) is dominated by the gas fill and less sensitive to patient positioning. In pseudophakic eyes with larger values of ACD, the graft coverage depends on gas fill and patient positioning with positioning even more important as ACD increases. Translational Relevance: Anterior chamber depth markedly influences the role of patient positioning in gas-filled eyes after DMEK due to the interplay between anterior chamber anatomy and gas bubble morphology

    Antinuclear antibodies (ANA) in chronic hepatitis C virus infection: correlates of positivity and clinical relevance.

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    We examined correlates of antinuclear antibody (ANA) positivity (ANA+) in individuals with chronic hepatitis C virus (HCV) infection and the effect of positivity on clinical outcome of HCV. Pretreatment sera from 645 patients from three centres in Sweden (n = 225), the UK (n = 207) and Italy (n = 213) were evaluated by indirect immunofluorescence on Hep-2 cells for ANA pattern and titre by a single laboratory. Liver biopsies were all scored by one pathologist. A total of 258 patients were subsequently treated with interferon monotherapy. There was a significant difference in the prevalence of ANA (1:40) by geographic location: Lund 4.4%, London 8.7%, Padova 10.3% [odds ratio (OR) = 0.66; 95% CI: 0.46-0.94; P = 0.023]. Duration of HCV infection, age at infection, current age, route of infection, viral genotype, alcohol consumption, fibrosis stage and inflammatory score were not correlated with ANA+ or ANA pattern. Female gender was correlated with ANA+ and this association persisted in multivariable analyses (OR = 3.0; P = 0.002). Increased plasma cells were observed in the liver biopsies of ANA-positive individuals compared with ANA-negative individuals, while a trend towards decreased lymphoid aggregates was observed [hazard ratio (HR) = 9.0, P = 0.037; HR = 0.291, P = 0.118, respectively]. No correlations were observed between ANA positivity and nonresponse to therapy (OR = 1.4; P = 0.513), although ANA+ was correlated with faster rates of liver fibrosis, this was not statistically significant (OR = 1.8; P = 0.1452). Low titre ANA+ should not be a contraindication for interferon treatment. Our observation of increased plasma cells in ANA+ biopsies might suggest B-cell polyclonal activity with a secondary clinical manifestation of increased serum immunoglobulins

    Expectation Maximization in Deep Probabilistic Logic Programming

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    Probabilistic Logic Programming (PLP) combines logic and probability for representing and reasoning over domains with uncertainty. Hierarchical probability Logic Programming (HPLP) is a recent language of PLP whose clauses are hierarchically organized forming a deep neural network or arithmetic circuit. Inference in HPLP is done by circuit evaluation and learning is therefore cheaper than any generic PLP language. We present in this paper an Expectation Maximization algorithm, called Expectation Maximization Parameter learning for HIerarchical Probabilistic Logic programs (EMPHIL), for learning HPLP parameters. The algorithm converts an arithmetic circuit into a Bayesian network and performs the belief propagation algorithm over the corresponding factor graph

    On fine differentiability properties of horizons and applications to Riemannian geometry

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    We study fine differentiability properties of horizons. We show that the set of end points of generators of a n-dimensional horizon H (which is included in a (n+1)-dimensional space-time M) has vanishing n-dimensional Hausdorff measure. This is proved by showing that the set of end points of generators at which the horizon is differentiable has the same property. For 1\le k\le n+1 we show (using deep results of Alberti) that the set of points where the convex hull of the set of generators leaving the horizon has dimension k is ``almost a C^2 manifold of dimension n+1-k'': it can be covered, up to a set of vanishing (n+1-k)-dimensional Hausdorff measure, by a countable number of C^2 manifolds. We use our Lorentzian geometry results to derive information about the fine differentiability properties of the distance function and the structure of cut loci in Riemannian geometry.Comment: Latex2e, 13 pages in A4 forma
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