775 research outputs found

    Noncommutative quantum mechanics and Bohm's ontological interpretation

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    We carry out an investigation into the possibility of developing a Bohmian interpretation based on the continuous motion of point particles for noncommutative quantum mechanics. The conditions for such an interpretation to be consistent are determined, and the implications of its adoption for noncommutativity are discussed. A Bohmian analysis of the noncommutative harmonic oscillator is carried out in detail. By studying the particle motion in the oscillator orbits, we show that small-scale physics can have influence at large scales, something similar to the IR-UV mixing

    Olive phenology as a sensitive indicator of future climatic warming in the Mediterranean

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    Experimental and modelling work suggests a strong dependence of olive flowering date on spring temperatures. Since airborne pollen concentrations reflect the flowering phenology of olive populations within a radius of 50 km, they may be a sensitive regional indicator of climatic warming. We assessed this potential sensitivity with phenology models fitted to flowering dates inferred from maximum airborne pollen data. Of four models tested, a thermal time model gave the best fit for Montpellier, France, and was the most effective at the regional scale, providing reasonable predictions for 10 sites in the western Mediterranean. This model was forced with replicated future temperature simulations for the western Mediterranean from a coupled ocean-atmosphere general circulation model (GCM). The GCM temperatures rose by 4·5 °C between 1990 and 2099 with a 1% per year increase in greenhouse gases, and modelled flowering date advanced at a rate of 6·2 d per °C. The results indicated that this long-term regional trend in phenology might be statistically significant as early as 2030, but with marked spatial variation in magnitude, with the calculated flowering date between the 1990s and 2030s advancing by 3–23 d. Future monitoring of airborne olive pollen may therefore provide an early biological indicator of climatic warming in the Mediterranean

    Nonsimplicity of certain universal C^*-algebras

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    Given n≥2" role="presentation">n≥2, zij∈T" role="presentation">zij∈T such that zij=z¯ji" role="presentation">zij=z¯ji for 1≤i,j≤n" role="presentation">1≤i,j≤n and zii=1" role="presentation">zii=1 for 1≤i≤n" role="presentation">1≤i≤n, and integers p1,…,pn≥1" role="presentation">p1,…,pn≥1, we show that the universal C*" role="presentation">C∗-algebra generated by unitaries u1,…,un" role="presentation">u1,…,un such that uipiujpj=zijujpjuipi" role="presentation">upiiupjj=zijupjjupii for 1≤i,j≤n" role="presentation">1≤i,j≤n is not simple if at least one exponent pi" role="presentation">pi is at least two. We indicate how the method of proof by “working with various quotients” can be used to establish nonsimplicity of universal C*" role="presentation">C∗-algebras in other cases.Article / Letter to editorMathematisch Instituu

    High Altitude test of RPCs for the ARGO-YBJ experiment

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    A 50 m**2 RPC carpet was operated at the YangBaJing Cosmic Ray Laboratory (Tibet) located 4300 m a.s.l. The performance of RPCs in detecting Extensive Air Showers was studied. Efficiency and time resolution measurements at the pressure and temperature conditions typical of high mountain laboratories, are reported.Comment: 16 pages, 10 figures, submitted to Nucl. Instr. Met

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

    Nonsimplicity of certain universal C^*-algebras

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    Given n≥2" role="presentation">n≥2, zij∈T" role="presentation">zij∈T such that zij=z¯ji" role="presentation">zij=z¯ji for 1≤i,j≤n" role="presentation">1≤i,j≤n and zii=1" role="presentation">zii=1 for 1≤i≤n" role="presentation">1≤i≤n, and integers p1,…,pn≥1" role="presentation">p1,…,pn≥1, we show that the universal C*" role="presentation">C∗-algebra generated by unitaries u1,…,un" role="presentation">u1,…,un such that uipiujpj=zijujpjuipi" role="presentation">upiiupjj=zijupjjupii for 1≤i,j≤n" role="presentation">1≤i,j≤n is not simple if at least one exponent pi" role="presentation">pi is at least two. We indicate how the method of proof by “working with various quotients” can be used to establish nonsimplicity of universal C*" role="presentation">C∗-algebras in other cases.Analysis and Stochastic
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