1,175 research outputs found

    Equivalent layered models for functionally graded plates

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    Functionally graded plates whose material properties vary continuously through the thickness are modelled as exactly equivalent plates composed of up to four isotropic layers. Separate models are derived for analysis using classical plate theory, first-order and higher-order shear deformation theory. For cases where Poisson’s ratio varies through the thickness, the integrations required to obtain the membrane, coupling and out-of-plane stiffness matrices are performed accurately using a series solution. The model is verified by comparison with well converged solutions from approximate models in which the plate is divided into many isotropic layers. Critical buckling loads and undamped natural frequencies are found for a range of illustrative examples

    Swallowing Activity Assessed by Ambulatory Impedance-pH Monitoring Predicts Awake and Asleep Periods at Night

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    Introduction: Voluntary muscle activity, including swallowing, decreases during the night. The association between nocturnal awakenings and swallowing activity is under-researched with limited information on the frequency of swallows during awake and asleep periods. Aim: The aim of this study was to assess nocturnal swallowing activity and identify a cut-off predicting awake and asleep periods. Methods: Patients undergoing impedance-pH monitoring as part of GERD work-up were asked to wear a wrist activity detecting device (Actigraph®) at night. Swallowing activity was quantified by analysing impedance changes in the proximal esophagus. Awake and asleep periods were determined using a validated scoring system (Sadeh algorithm). Receiver operating characteristics (ROC) analyses were performed to determine sensitivity, specificity and accuracy of swallowing frequency to identify awake and asleep periods. Results: Data from 76 patients (28male, 48 female; mean age 56±15years) were included in the analysis. The ROC analysis found that 0.33sw/min (i.e. one swallow every 3min) had the optimal sensitivity (78%) and specificity (76%) to differentiate awake from asleep periods. A swallowing frequency of 0.25sw/min (i.e. one swallow every 4min) was 93% sensitive and 57% specific to identify awake periods. A swallowing frequency of 1sw/min was 20% sensitive but 96% specific in identifying awake periods. Summary and Conclusion: Impedance-pH monitoring detects differences in swallowing activity during awake and asleep periods. Swallowing frequency noticed during ambulatory impedance-pH monitoring can predict the state of consciousness during nocturnal period

    Electron neutrino tagging through tertiary lepton detection

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    We discuss an experimental technique aimed at tagging electron neutrinos in multi-GeV artificial sources on an event-by-event basis. It exploits in a novel manner calorimetric and tracking technologies developed in the framework of the LHC experiments and of rare kaon decay searches. The setup is suited for slow-extraction, moderate power beams and it is based on an instrumented decay tunnel equipped with tagging units that intercept secondary and tertiary leptons from the bulk of undecayed \pi^+ and protons. We show that the taggers are able to reduce the \nue contamination originating from K_e3 decays by about one order of magnitude. Only a limited suppression (~60%) is achieved for \nue produced by the decay-in-flight of muons; for low beam powers, similar performance as for K_e3 can be reached supplementing the tagging system with an instrumented beam dump.Comment: 19 pages, 7 figures; minor changes, version to appear in EPJ

    Nonadditive entropy and nonextensive statistical mechanics - Some central concepts and recent applications

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    We briefly review central concepts concerning nonextensive statistical mechanics, based on the nonadditive entropy Sq=k1ipiqq1(qR;S1=kipilnpi)S_q=k\frac{1-\sum_{i}p_i^q}{q-1} (q \in {\cal R}; S_1=-k\sum_{i}p_i \ln p_i). Among others, we focus on possible realizations of the qq-generalized Central Limit Theorem, including at the edge of chaos of the logistic map, and for quasi-stationary states of many-body long-range-interacting Hamiltonian systems.Comment: 15 pages, 9 figs., to appear in Journal of Physics: Conf.Series (IOP, 2010

    Two experiments for the price of one? -- The role of the second oscillation maximum in long baseline neutrino experiments

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    We investigate the quantitative impact that data from the second oscillation maximum has on the performance of wide band beam neutrino oscillation experiments. We present results for the physics sensitivities to standard three flavor oscillation, as well as results for the sensitivity to non-standard interactions. The quantitative study is performed using an experimental setup similar to the Fermilab to DUSEL Long Baseline Neutrino Experiment (LBNE). We find that, with the single exception of sensitivity to the mass hierarchy, the second maximum plays only a marginal role due to the experimental difficulties to obtain a statistically significant and sufficiently background-free event sample at low energies. This conclusion is valid for both water Cherenkov and liquid argon detectors. Moreover, we confirm that non-standard neutrino interactions are very hard to distinguish experimentally from standard three-flavor effects and can lead to a considerable loss of sensitivity to \theta_{13}, the mass hierarchy and CP violation.Comment: RevTex 4.1, 23 pages, 10 figures; v2: Typos corrected, very minor clarifications; matches published version; v3: Fixed a typo in the first equation in sec. III

    Confusion Assessment Method for the intensive care unit (CAM-ICU) for the diagnosis of delirium in adults in critical care settings

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    © 2018 The Cochrane Collaboration. This is a protocol for a Cochrane Review (Diagnostic test accuracy). The objectives are as follows: To determine the diagnostic accuracy of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) for the diagnosis of delirium in adult patients in critical care settings

    IC 751: a new changing-look AGN discovered by NuSTAR

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    We present the results of five NuSTAR observations of the type 2 active galactic nucleus (AGN) in IC 751, three of which were performed simultaneously with XMM-Newton or Swift/XRT. We find that the nuclear X-ray source underwent a clear transition from a Compton-thick (NH2×1024cm2N_{\rm\,H}\simeq 2\times 10^{24}\rm\,cm^{-2}) to a Compton-thin (NH4×1023cm2N_{\rm\,H}\simeq 4\times 10^{23}\rm\,cm^{-2}) state on timescales of 3\lesssim 3 months, which makes IC 751 the first changing-look AGN discovered by NuSTAR. Changes of the line-of-sight column density at a 2σ\sim2\sigma level are also found on a time-scale of 48\sim 48 hours (ΔNH1023cm2\Delta N_{\rm\,H}\sim 10^{23}\rm\,cm^{-2}). From the lack of spectral variability on timescales of 100\sim 100 ks we infer that the varying absorber is located beyond the emission-weighted average radius of the broad-line region, and could therefore be related either to the external part of the broad-line region or a clumpy molecular torus. By adopting a physical torus X-ray spectral model, we are able to disentangle the column density of the non-varying absorber (NH3.8×1023cm2N_{\rm\,H}\sim 3.8\times 10^{23}\rm\,cm^{-2}) from that of the varying clouds [NH(1150)×1022cm2N_{\rm\,H}\sim(1-150)\times10^{22}\rm\,cm^{-2}], and to constrain that of the material responsible for the reprocessed X-ray radiation (NH6×1024cm2N_{\rm\,H} \sim 6 \times 10^{24}\rm\,cm^{-2}). We find evidence of significant intrinsic X-ray variability, with the flux varying by a factor of five on timescales of a few months in the 2-10 and 10-50 keV band.Comment: Accepted for publication in ApJ, 11 pages, 6 figure

    Fungos isolados de Meloidogyne mayaguensis em raízes de goiabeiras infectadas.

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