14,068 research outputs found

    Fast and Simple Relational Processing of Uncertain Data

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    This paper introduces U-relations, a succinct and purely relational representation system for uncertain databases. U-relations support attribute-level uncertainty using vertical partitioning. If we consider positive relational algebra extended by an operation for computing possible answers, a query on the logical level can be translated into, and evaluated as, a single relational algebra query on the U-relation representation. The translation scheme essentially preserves the size of the query in terms of number of operations and, in particular, number of joins. Standard techniques employed in off-the-shelf relational database management systems are effective for optimizing and processing queries on U-relations. In our experiments we show that query evaluation on U-relations scales to large amounts of data with high degrees of uncertainty.Comment: 12 pages, 14 figure

    Progressive managerial bonuses in a spatial Bertrand duopoly

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    The relationship of managerial bonuses and profit maximization is interesting both from an economic and a managerial viewpoint. Our contribution to this literature is showing that progressive managerial bonuses can increase profits in a spatial Bertrand competition, and furthermore they can help collusion

    A double-blind study of the efficacy of apomorphine and its assessment in "off-periods in Parkinson's disease

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    Five patients with idiopathic Parkinson's disease with severe response fluctuations were selected for a randomized double-blind placebo-controlled study, concerning the clinical effects of subcutaneous apomorphine and its assessment in `off¿-periods. The study was designed as five n = 1 studies, in which every patient was his own control. The effect of apomorphine was studied by using the Columbia rating scale and quantitative assessments, using tapping, walking and pinboard. There was a significant positive effect of apomorphine, in a mean optimal dose of 2.7 mg, with a mean latency of onset of 7.3 min and a mean duration of response of 96 min. After pretreatment with domperidone, no significant adverse effects were observed. Tapping showed the highest correlation with rigidity and bradykinesia. Walking showed a high correlation with stability and gait. Pinboard testing did not give additional information. The first conclusion was that apomorphine proved to be a significantly effective dopamine agonist, proven now also by a double blind placebo-controlled study. Secondly it was concluded that assessment of clinical effect in parkinsonian patients can be performed best by combining the Columbia item tremor with tapping and walking scores

    Two-Dimensional Spectroscopy of Extended Molecular Systems: Applications to Energy Transport and Relaxation in an α-Helix

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    A simulation study of the coupled dynamics of amide I and amide II vibrations in an α-helix dissolved in water shows that two-dimensional (2D) infrared spectroscopy may be used to disentangle the energy transport along the helix through each of these modes from the energy relaxation between them. Time scales for both types of processes are obtained. Using polarization-dependent 2D spectroscopy is an important ingredient in the method we propose. The method may also be applied to other two-band systems, both in the infrared (collective vibrations) and the visible (excitons) parts of the spectrum.

    The eta' meson from lattice QCD

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    We study the flavour singlet pseudoscalar mesons from first principles using lattice QCD. With N_f=2 flavours of light quark, this is the so-called eta_2 meson and we discuss the phenomenological status of this. Using maximally twisted-mass lattice QCD, we extract the mass of the eta_2 meson at two values of the lattice spacing for lighter quarks than previously discussed in the literature. We are able to estimate the mass value in the limit of light quarks with their physical masses.Comment: 16 pages: version accepted for publicatio

    One-dimensional quantum antiferromagnetism in the pp-orbital CsO2_2 compound revealed by electron paramagnetic resonance

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    Recently it was proposed that the orbital ordering of πx,y\pi_{x,y}^* molecular orbitals in the superoxide CsO2_2 compound leads to the formation of spin-1/2 chains below the structural phase transition occuring at Ts1=61T_{\rm{s1}}=61~K on cooling. Here we report a detailed X-band electron paramagnetic resonance (EPR) study of this phase in CsO2_2 powder. The EPR signal appears as a broad line below Ts1T_{\rm{s1}}, which is replaced by the antiferromagnetic resonance below the N\'{e}el temperature TN=8.3T_{\rm N}=8.3~K. The temperature dependence of the EPR linewidth between Ts1T_{\rm{s1}} and TNT_{\rm{N}} agrees with the predictions for the one-dimensional Heisenberg antiferromagnetic chain of S=1/2S=1/2 spins in the presence of symmetric anisotropic exchange interaction. Complementary analysis of the EPR lineshape, linewidth and the signal intensity within the Tomonaga-Luttinger liquid (TLL) framework allows for a determination of the TLL exponent K=0.48K=0.48. Present EPR data thus fully comply with the quantum antiferromagnetic state of spin-1/2 chains in the orbitally ordered phase of CsO2_2, which is, therefore, a unique pp-orbital system where such a state could be studied.Comment: 6 pages, 3 figure

    Improved Fixed-Budget Results via Drift Analysis

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    Fixed-budget theory is concerned with computing or bounding the fitness value achievable by randomized search heuristics within a given budget of fitness function evaluations. Despite recent progress in fixed-budget theory, there is a lack of general tools to derive such results. We transfer drift theory, the key tool to derive expected optimization times, to the fixed-budged perspective. A first and easy-to-use statement concerned with iterating drift in so-called greed-admitting scenarios immediately translates into bounds on the expected function value. Afterwards, we consider a more general tool based on the well-known variable drift theorem. Applications of this technique to the LeadingOnes benchmark function yield statements that are more precise than the previous state of the art.Comment: 25 pages. An extended abstract of this paper will be published in the proceedings of PPSN 202
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