6,373 research outputs found

    Scattering lengths and universality in superdiffusive L\'evy materials

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    We study the effects of scattering lengths on L\'evy walks in quenched one-dimensional random and fractal quasi-lattices, with scatterers spaced according to a long-tailed distribution. By analyzing the scaling properties of the random-walk probability distribution, we show that the effect of the varying scattering length can be reabsorbed in the multiplicative coefficient of the scaling length. This leads to a superscaling behavior, where the dynamical exponents and also the scaling functions do not depend on the value of the scattering length. Within the scaling framework, we obtain an exact expression for the multiplicative coefficient as a function of the scattering length both in the annealed and in the quenched random and fractal cases. Our analytic results are compared with numerical simulations, with excellent agreement, and are supposed to hold also in higher dimensionsComment: 6 pages, 8 figure

    Internal alignment and position resolution of the silicon tracker of DAMPE determined with orbit data

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    The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei components between 10 GeV and 100 TeV. The silicon-tungsten tracker-converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron-positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m2^2. Silicon planes are interleaved with three layers of tungsten plates, resulting in about one radiation length of material in the tracker. Internal alignment parameters of the tracker have been determined on orbit, with non-showering protons and helium nuclei. We describe the alignment procedure and present the position resolution and alignment stability measurements

    Production of Λ6^{6}_{\Lambda}H and Λ7^{7}_{\Lambda}H with the (Kstop^{-}_{stop},π+\pi^+) reaction

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    The production of neutron rich Λ\Lambda-hypernuclei via the (KstopK^-_stop,π+\pi^+) reaction has been studied using data collected with the FINUDA spectrometer at the DAΦ\PhiNE ϕ\phi-factory (LNF). The analysis of the inclusive π+\pi^+ momentum spectra is presented and an upper limit for the production of Λ6^6_\LambdaH and Λ7^7_\LambdaH from 6^6Li and 7^7Li, is assessed for the first time.Comment: 11 pages, 3 figures. Accepted for publication in PL

    A study of the proton spectra following the capture of KK^- in 6^6Li and 12^{12}C with FINUDA

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    Momenta spectra of protons emitted following the capture of KK^- in 6^6Li and 12^{12}C have been measured with 1% resolution. The 12^{12}C spectrum is smooth whereas for 6^6Li a well defined peak appears at about 500 MeV/cc. The first observation of a structure in this region was identified as a strange tribaryon or, possibly, a Kˉ\bar K-nuclear state. The peak is correlated with a π\pi^- coming from Σ\Sigma^- decay in flight, selected by setting momenta larger than 275 MeV/cc. The Σ\Sigma^- could be produced, together with a 500 MeV/cc proton, by the capture of a KK^- in a deuteron-cluster substructure of the 6^6Li nucleus. The capture rate for such a reaction is (1.62\pm 0.23_{stat} ^{+0.71}_{-0.44}(sys))%/K^-_{stop}, in agreement with the existing observations on 4^4He targets and with the hypothesis that the 6^6Li nucleus can be interpreted as a (d+α)(d+\alpha) cluster.Comment: 21 pages, 10 figures. Accepted for publication in NP

    Correlated Λd\Lambda d pairs from the KstopAΛdAK^{-}_{stop} A \to \Lambda d A' reaction

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    Correlated Λd\Lambda d pairs emitted after the absorption of negative kaons at rest KstopAΛdAK^{-}_{stop}A\to \Lambda d A' in light nuclei 6Li^6Li and 12C^{12}C are studied. Λ\Lambda-hyperons and deuterons are found to be preferentially emitted in opposite directions. The Λd\Lambda d invariant mass spectrum of 6Li^6Li shows a bump whose mass is 3251±\pm6 MeV/c2^2. The bump mass (binding energy), width and yield are reported. The appearance of a bump is discussed in the realm of the [Kˉ3N\bar{K}3N] clustering process in nuclei. The experiment was performed with the FINUDA spectrometer at DAΦ\PhiNE (LNF).Comment: 13 pages, 5 figures, accepted for publication in Phys. Lett.

    How the mere desire for certainty can lead to a preference for men in authority (particularly among political liberals)

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    Women are harmed by stereotypes about their fit for positions of authority and changing these stereotypes is not a simple task. As stereotypes have strong epistemic properties, individuals with a high need for cognitive closure (NCC; i.e., the desire for epistemic certainty) can be more likely to accept these stereotypes and, consequently, to prefer men in positions of authority. Consistent with the reactive liberal hypothesis, this effect could be actually more visible among individuals with both a high NCC and left-wing political orientations. We supported these hypotheses in a series of three studies. In Study 1 (N = 217), we found that manipulated NCC predicted preference for men in authority through stereotypes of women as not being fit for authority in a measurement-of-mediation design. In Study 2 (N = 151), we supported this effect in a mediation-as-process design. In Study 3 (N = 391), we found the indirect NCC effect on preference for men in authority was more visible among political liberals. A major implication of this work is that ways of changing the effect of these stereotypes should take into account the NCC, but particularly among individuals with left-wing beliefs

    Measurement of the production of charged pions by protons on a tantalum target

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    A measurement of the double-differential cross-section for the production of charged pions in proton--tantalum collisions emitted at large angles from the incoming beam direction is presented. The data were taken in 2002 with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \GeVc to 12 \GeVc hitting a tantalum target with a thickness of 5% of a nuclear interaction length. The angular and momentum range covered by the experiment (100 \MeVc \le p < 800 \MeVc and 0.35 \rad \le \theta <2.15 \rad) is of particular importance for the design of a neutrino factory. The produced particles were detected using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. Track recognition, momentum determination and particle identification were all performed based on the measurements made with the TPC. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d2σ/dpdθ{{\mathrm{d}^2 \sigma}} / {{\mathrm{d}p\mathrm{d}\theta}} at four incident proton beam momenta (3 \GeVc, 5 \GeVc, 8 \GeVc and 12 \GeVc). In addition, the pion yields within the acceptance of typical neutrino factory designs are shown as a function of beam momentum. The measurement of these yields within a single experiment eliminates most systematic errors in the comparison between rates at different beam momenta and between positive and negative pion production.Comment: 49 pages, 31 figures. Version accepted for publication on Eur. Phys. J.

    Transcriptome profiling of grapevine seedless segregants during berry development reveals candidate genes associated with berry weight

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    Indexación: Web of Science; PubMedBackground Berry size is considered as one of the main selection criteria in table grape breeding programs. However, this is a quantitative and polygenic trait, and its genetic determination is still poorly understood. Considering its economic importance, it is relevant to determine its genetic architecture and elucidate the mechanisms involved in its expression. To approach this issue, an RNA-Seq experiment based on Illumina platform was performed (14 libraries), including seedless segregants with contrasting phenotypes for berry weight at fruit setting (FST) and 6–8 mm berries (B68) phenological stages. Results A group of 526 differentially expressed (DE) genes were identified, by comparing seedless segregants with contrasting phenotypes for berry weight: 101 genes from the FST stage and 463 from the B68 stage. Also, we integrated differential expression, principal components analysis (PCA), correlations and network co-expression analyses to characterize the transcriptome profiling observed in segregants with contrasting phenotypes for berry weight. After this, 68 DE genes were selected as candidate genes, and seven candidate genes were validated by real time-PCR, confirming their expression profiles. Conclusions We have carried out the first transcriptome analysis focused on table grape seedless segregants with contrasting phenotypes for berry weight. Our findings contributed to the understanding of the mechanisms involved in berry weight determination. Also, this comparative transcriptome profiling revealed candidate genes for berry weight which could be evaluated as selection tools in table grape breeding programs.http://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-016-0789-
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