4,630 research outputs found

    Angle-resolved photoemission study of insulating and metallic Cu-O chains in PrBa2_2Cu3_3O7_7 and PrBa2_2Cu4_4O8_8

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    We compare the angle-resolved photoemission spectra of the hole-doped Cu-O chains in PrBa2_2Cu3_3O7_7 (Pr123) and in PrBa2_2Cu4_4O8_8 (Pr124). While, in Pr123, a dispersive feature from the chain takes a band maximum at kbk_b (momentum along the chain) \sim π/4\pi/4 and loses its spectral weight around the Fermi level, it reaches the Fermi level at kbk_b \sim π/4\pi/4 in Pr124. Although the chains in Pr123 and Pr124 are approximately 1/4-filled, they show contrasting behaviors: While the chains in Pr123 have an instability to charge ordering, those in Pr124 avoid it and show an interesting spectral feature of a metallic coupled-chain system.Comment: 4 pages, 5 figures, to be published in PR

    How Sensitive Are Our Eyes to Text Difficulty? : Application of Schema Fixation Curves to Japanese Text

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    This paper discusses the applicability of Schema Fixation Curves to the detection of changes in the behavior of eye movements in accordance with the readability of text. If the eyes are to respond to the degree of difficulty of the given task, we may say that the eyes are an output device of our cognitive activities. Our previous research led us to the notation of Schema Fixation and Schema Fixation Curves, a technique with which graphically analyze the cognitive load the subjects bear when they read texts. The results of our experiments based on this technique show that the eye movement records are a good clue to the detection of text difficulty or readability of texts. Conventionally, computer-calculated readability indices have been used to predict text readability, but the precision of the prediction may not necessarily be so high. This is because most of these indices use syntactic elements of text such as average sentence length and word length. Difficulty of texts arises from a variety of factors, such as the reader\u27s background knowledge of the passage, the range of vocabulary used in the text, syntactic and semantic ambiguities, etc. In this experiment, we used the Japanese language in order to focus on syntactic effect on readability. Japanese allows much freer syntactic structure than present-day English. For example, the natural, normal, and unstressed word order of English (from amongst the six logical possibilities, SVO, SOV, VSO, VOS, OSV, OVS) is SVO while various combinations are both possible and natural in Japanese. We changed the syntactic order of words in sentences and presented them to the subjects in order to examine the recorded eye movements, and found that different orders produced different levels of readability

    Acute WNT signalling activation perturbs differentiation within the adult stomach and rapidly leads to tumour formation

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    A role for WNT signalling in gastric carcinogenesis has been suggested due to two major observations. First, patients with germline mutations in adenomatous polyposis coli (APC) are susceptible to stomach polyps and second, in gastric cancer, WNT activation confers a poor prognosis. However, the functional significance of deregulated WNT signalling in gastric homoeostasis and cancer is still unclear. In this study we have addressed this by investigating the immediate effects of WNT signalling activation within the stomach epithelium. We have specifically activated the WNT signalling pathway within the mouse adult gastric epithelium via deletion of either glycogen synthase kinase 3 (GSK3) or APC or via expression of a constitutively active β-catenin protein. WNT pathway deregulation dramatically affects stomach homoeostasis at very short latencies. In the corpus, there is rapid loss of parietal cells with fundic gland polyp (FGP) formation and adenomatous change, which are similar to those observed in familial adenomatous polyposis. In the antrum, adenomas occur from 4 days post-WNT activation. Taken together, these data show a pivotal role for WNT signalling in gastric homoeostasis, FGP formation and adenomagenesis. Loss of the parietal cell population and corresponding FGP formation, an early event in gastric carcinogenesis, as well as antral adenoma formation are immediate effects of nuclear β-catenin translocation and WNT target gene expression. Furthermore, our inducible murine model will permit a better understanding of the molecular changes required to drive tumourigenesis in the stomach

    Observation of X(3872)J/ψγX(3872)\to J/\psi \gamma and search for X(3872)ψγX(3872)\to\psi'\gamma in B decays

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    We report a study of B(J/ψγ)KB\to (J/\psi \gamma) K and B(ψγ)KB\to (\psi' \gamma)K decay modes using 772×106772\times 10^{6} BBˉB\bar{B} events collected at the \Upsilon(4S)resonancewiththeBelledetectorattheKEKBenergyasymmetric resonance with the Belle detector at the KEKB energy-asymmetric e^+ e^-collider.Weobserve collider. We observe X(3872) \to J/\psi \gammaandreportthefirstevidencefor and report the first evidence for \chi_{c2} \to J/\psi \gammain in B\to (X_{c\bar{c}}\gamma) Kdecays,whileinasearchfor decays, while in a search for X(3872) \to \psi' \gammanosignificantsignalisfound.Wemeasurethebranchingfractions, no significant signal is found. We measure the branching fractions, \mathcal{B}(B^{\pm} \to X(3872) K^{\pm}) \mathcal{B}(X(3872) \to J/\psi\gamma) = (1.78^{+0.48}_{-0.44}\pm 0.12)\times 10^{-6},, \mathcal{B} (B^{\pm} \to\chi_{c2} K^{\pm})= (1.11^{+0.36}_{-0.34} \pm 0.09) \times 10^{-5},, \mathcal{B}(B^{\pm} \to X(3872) K^{\pm}) \mathcal{B}(X(3872) \to \psi'\gamma) < 3.45\times 10^{-6}$ (upper limit at 90% C.L.) and also provide upper limits for other searches.Comment: 6 pages, 3 figure

    First Observation of Radiative B^0 -> \phi K^0 \gamma Decays and Measurements of Their Time-Dependent CP Violation

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    We report the first observation of the radiative decay B^0 -> \phi K^0 \gamma using a data sample of 772 x 10^6 B B-bar pairs collected at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We observe a signal of 37+/-8 events with a significance of 5.4 standard deviations including systematic uncertainties. The measured branching fraction is B(B0>ϕK0γ)=(2.74±0.60±0.32)×106{\cal B}(B^0 -> \phi K^0 \gamma) = (2.74\pm 0.60 \pm 0.32) \times 10^{-6}, where the uncertainties are statistical and systematic, respectively. We also report the first measurements of time-dependent CP violation parameters: SϕKS0γ=+0.741.05+0.72(stat)0.24+0.10(syst){\mathcal S}_{\phi K_S^0 \gamma} = +0.74^{+0.72}_{-1.05} (stat)^{+0.10}_{-0.24} (syst) and AϕKS0γ=+0.35+/0.58(stat)0.10+0.23(syst){\mathcal A}_{\phi K_S^0 \gamma} = +0.35 +/- 0.58 (stat)^{+0.23}_{-0.10} (syst). Furthermore, we measure B(B+>ϕK+γ)=(2.48+/0.30+/0.24)x106{\mathcal B}(B^+ -> \phi K^+ \gamma) = (2.48 +/- 0.30 +/- 0.24) x 10^{-6}, ACP=0.03+/0.11+/0.08{\mathcal A}_{CP} = -0.03 +/- 0.11 +/- 0.08 and find that the signal is concentrated in the M_{\phi K} mass region near threshold.Comment: 6 pages, 3 figures, Modified version is to be published in PRD(RC

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Performance de novilhas holandesas alimentadas com silagens de cana-de-açúcar tratadas com uréia, benzoato de sódio ou Lactobacillus Buchneri.

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    A fermentação alcoólica influencia negativamente a qualidade de silagens de cana-de-açúcar e pode prejudicar a performance dos animais. Alguns aditivos podem reduzir a produção de etanol e as perdas nessas silagens. Este experimento objetivou avaliar a performance de novilhas alimentadas com rações contendo silagens de cana-de-açúcar aditivadas ou sem tratamento. Trinta e duas novilhas Holandesas foram aleatoriamente distribuídas em um delineamento em blocos, para avaliar rações (46% silagem; 54% concentrado; 12% proteína bruta) contendo silagem sem aditivo (controle) ou silagens tratadas com (base matéria verde) uréia (0,5%), benzoato de sódio (0,1 %) ou "Lactobacillus buchneri" (3,64 x 10"5" ufc g"-1"). A inoculação com "Lactobacillus buchneri" melhorou (P < 0,01) o ganho diário (1,24 vs 0,94 kg/dia) e com o benzoato melhorou a conversão alimentar (7.6 vs 9,4 kg de matéria seca/kg de peso vivo). Os tratamentos não afetaram o consumo de matéria seca (2,19% do peso vivo, em média. O tratamento com uréia não tenha melhorou o desempenho dos animais. Concluiu-se que o tratamento com aditivos pode ser um método eficiente para obtenção de silagens de cana-de-açúcar de melhor valor nutritivo

    Bounds on the width, mass difference and other properties of X(3872) --> pi+pi-J/psi decays

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    We present results from a study of X(3872) --> pi+pi- J/psi decays produced via exclusive B--> K X(3872) decays. We determine the mass to be M_X(3872)= (3871.84\pm 0.27 (stat)\pm 0.19 (syst)) MeV, a 90% CL upper limit on the natural width of Gamma_X(3872) K+X(3872))xBf(X(3872)-->pi+pi-J/psi)=(8.61 \pm 0.82(stat) \pm 0.52 (syst)) x10^{-6}, and a ratio of branching fractions Bf(B0--> K0 X(3872))/BF(B+--> K+ X(3872))=0.50\pm 0.14(stat)\pm0.04(syst). The difference in mass between the X(3872)-->pi+pi-J/psi signals in B+ and B0 decays is Delta M_{X(3872)= (-0.69 \pm 0.97 (stat)} \pm 0.19 (syst)) MeV. A search for a charged partner of the X(3872) in the decays Bbar0-->K- X+ or B+-->K0X+, X+-->pi+pi0 J/psi resulted in upper limits on the product branching fractions for these processes that are well below expectations for the case that the X(3872) is the neutral member of an isospin triplet. In addition, we examine possible J^{PC} quantum number assignments for the X(3872) based on comparisons of angular correlations between final state particles in X(3872)-->pi+pi-J/psi decays with simulated data for J^{PC} values of 1^{++} and 2^{-+}. We examine the influence of rho-omega interference in the M(pi+pi-) spectrum. The analysis is based on a 711fb^{-1} data sample that contains 772 million BBbar meson pairs collected at the Upsilon(4S) resonance in the Belle detector at the KEKB e+e- collider.Comment: 15 pages, 10 figures and 6 tables. Submitted to Physical Review
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