349 research outputs found

    Observation of the Resonant Character of the Z(4430)(-) State

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    Resonant structures in B-0 -> psi'pi K--(+) decays are analyzed by performing a four-dimensional fit of the decay amplitude, using pp collision data corresponding to 3 fb(-1) collected with the LHCb detector. The data cannot be described with K+pi(-) resonances alone, which is confirmed with a model-independent approach. A highly significant Z(4430)(-) -> psi'pi(-) component is required, thus confirming the existence of this state. The observed evolution of the Z(4430)(-) amplitude with the psi'pi(-) mass establishes the resonant nature of this particle. The mass and width measurements are substantially improved. The spin parity is determined unambiguously to be 1(+)

    Capacity and Procedural Accounts of Impaired Memory in Depression

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    Findings of impaired memory in states of dysphoria or depression are summarized and subsumed under different accounts of mood-related memory deficits. Theoretical accounts based on the assumption of a storage system of limited capacity are compared to accounts which emphasize the role of procedures and strategies in attending and remembering. Two reanalyses of a recent experiment in the process-dissociation paradigm are reported. They address issues of dysphoria-related differences in automatic versus controlled uses of memory in a task of word-stem completion. The two reanalyses rest on different assumptions about the relation between automatic and controlled components, but they converge in highlighting the advantages of a procedural rather than capacity-based view of memory deficits. finally. similarities to other research domains and theoretical approaches are outlined

    Chronic hepatitis c genotype-4 infection: role of insulin resistance in hepatocellular carcinoma

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    <p>Abstract</p> <p>Background</p> <p>Hepatitis C virus (HCV) is a major cause of chronic hepatitis and hepatocellular carcinoma (HCC) and different HCV genotypes show characteristic variations in their pathological properties. Insulin resistance (IR) occurs early in HCV infection and may synergize with viral hepatitis in HCC development. Egypt has the highest reported rates of HCV infection (predominantly genotype 4) in the world; this study investigated effects of HCV genotype-4 (HCV-4) on prevalence of insulin resistance in chronic hepatitis C (CHC) and HCC in Egyptian patients.</p> <p>Methods</p> <p>Fifty CHC patients, 50 HCC patients and 20 normal subjects were studied. IR was estimated using HOMA-IR index and HCV-4 load determined using real-time polymerase chain reaction. Hepatitis B virus was excluded by enzyme-linked immunosorbent assay. Standard laboratory and histopathological investigations were undertaken to characterize liver function and for grading and staging of CHC; HCC staging was undertaken using intraoperative samples.</p> <p>Results</p> <p>HCC patients showed higher IR frequency but without significant difference from CHC (52% vs 40%, p = 0.23). Multivariate logistic regression analysis showed HOMA-IR index and International Normalization Ratio independently associated with fibrosis in CHC; in HCC, HbA1c, cholesterol and bilirubin were independently associated with fibrosis. Fasting insulin and cholesterol levels were independently associated with obesity in both CHC and HCC groups. Moderate and high viral load was associated with high HOMA-IR in CHC and HCC (p < 0.001).</p> <p>Conclusions</p> <p>IR is induced by HCV-4 irrespective of severity of liver disease. IR starts early in infection and facilitates progression of hepatic fibrosis and HCC development.</p

    Cognitive and Tactile Factors Affecting Human Haptic Performance in Later Life

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    Background: Vision and haptics are the key modalities by which humans perceive objects and interact with their environment in a target-oriented manner. Both modalities share higher-order neural resources and the mechanisms required for object exploration. Compared to vision, the understanding of haptic information processing is still rudimentary. Although it is known that haptic performance, similar to many other skills, decreases in old age, the underlying mechanisms are not clear. It is yet to be determined to what extent this decrease is related to the age-related loss of tactile acuity or cognitive capacity. Methodology/Principal Findings: We investigated the haptic performance of 81 older adults by means of a cross-modal object recognition test. Additionally, we assessed the subjects ’ tactile acuity with an apparatus-based two-point discrimination paradigm, and their cognitive performance by means of the non-verbal Raven-Standard-Progressive matrices test. As expected, there was a significant age-related decline in performance on all 3 tests. With the exception of tactile acuity, this decline was found to be more distinct in female subjects. Correlation analyses revealed a strong relationship between haptic and cognitive performance for all subjects. Tactile performance, on the contrary, was only significantly correlated with male subjects ’ haptic performance. Conclusions: Haptic object recognition is a demanding task in old age, especially when it comes to the exploration o

    Measurement of the CKM angle γ using<i> B</i><sup>±</sup> → <i>DK</i><sup>±</sup> with D → K <sub>S</sub> <sup>0</sup> π<sup>+</sup>π<sup>−</sup>, K <sub>S</sub> <sup>0</sup> K<sup>+</sup>K<sup>−</sup> decays

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    A binned Dalitz plot analysis of B±DK±B^\pm \to D K^\pm decays, with DKS0π+πD\to K_\text{S}^0\pi^+\pi^- and DKS0K+KD\to K_\text{S}^0K^+K^-, is used to perform a measurement of the CP-violating observables x±x_{\pm} and y±y_{\pm}, which are sensitive to the Cabibbo-Kobayashi-Maskawa angle γ\gamma. The analysis is performed without assuming any DD decay model, through the use of information on the strong-phase variation over the Dalitz plot from the CLEO collaboration. Using a sample of proton-proton collision data collected with the LHCb experiment in 2015 and 2016, and corresponding to an integrated luminosity of 2.0fb1\,\text{fb}^{-1}, the values of the CP violation parameters are found to be x=(9.0±1.7±0.7±0.4)×102x_- = ( 9.0 \pm 1.7 \pm 0.7 \pm 0.4) \times 10^{-2}, y=(2.1±2.2±0.5±1.1)×102y_- = ( 2.1 \pm 2.2 \pm 0.5 \pm 1.1) \times 10^{-2}, x+=(7.7±1.9±0.7±0.4)×102x_+ = (- 7.7 \pm 1.9 \pm 0.7 \pm 0.4) \times 10^{-2}, and y+=(1.0±1.9±0.4±0.9)×102y_+ = (- 1.0 \pm 1.9 \pm 0.4 \pm 0.9) \times 10^{-2}. The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the strong-phase measurements. These values are used to obtain γ=(8712+11)\gamma = \left(87\,^{+11}_{-12}\right)^\circ, rB=0.0860.014+0.013r_B = 0.086^{+ 0.013}_{-0.014}, and δB=(101±11)\delta_B = (101 \pm 11)^\circ, where rBr_B is the ratio between the suppressed and favoured BB-decay amplitudes and δB\delta_B is the corresponding strong-interaction phase difference. This measurement is combined with the result obtained using 2011 and 2012 data collected with the \lhcb experiment, to give γ=(809+10)\gamma = \left(80\,^{+10}_{\,-9}\right)^\circ, rB=0.080±0.011r_B = 0.080 \pm 0.011, and δB=(110±10)\delta_B = (110 \pm 10)^\circ.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2018-017.html. Version 2 includes minor changes made during journal revie

    Curvature-bias corrections using a pseudomass method

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    Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √s = 13 TeV during 2016, 2017 and 2018. The biases are determined using Z → μ+μ- decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z → μ+μ- mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass

    Measurement of the CKM angle γ in the B0→DK *0 channel using self-conjugate D→ KS0h+ h- decays

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    A model-independent study of CP violation in B-0 -&gt; DK (*0) decays is presented using data corresponding to an integrated luminosity of 9 fb(-1) collected by the LHCb experiment at centre-of-mass energies of v s = 7, 8 and 13TeV. The CKM angle. is determined by examining the distributions of signal decays in phase-space bins of the self-conjugate D. K(S)(0)h(+) h(-) decays, where h = p, K. Observables related to CP violation are measured and the angle. is determined to be. = (49+22 -19).. Measurements of the amplitude ratio and strong-phase difference between the favoured and suppressed B-0 decays are also presented

    Welcome in! How the academy can warrant recognition of young children as researchers

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    The academy has tended to marginalise young children as researchers, even in matters affecting them, which denies young children agency and amounts to social injustice. Drawing on the Young Children As Researchers (YCAR) study, which adopted a qualitative ‘jigsaw’ methodology to co-research with children aged 4-8 years (n=138), their parents, practitioners, and professional researchers, this article considers epistemological factors and epistemological categories that may support young children’s research behaviours in everyday activities. Those support structures are helpful in securing a warrant for recognising young children’s self-directed research on the academy’s terms. That recognition has potential to re-position young children away from the margins of research to an intrinsic position in research concerning matters that affect them, securing their rights as researchers. Such research can inform early childhood policy and practice in a deeply grounded manner that values young children as competent thinkers with expertise concerning their own lives
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