630 research outputs found

    Authors' Response to Peer Reviews of “Using Structural Equation Modelling in Routine Clinical Data on Diabetes and Depression: Observational Cohort Study”

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    Background: Large data sets comprising routine clinical data are becoming increasingly available for use in health research. These data sets contain many clinical variables that might not lend themselves to use in research. Structural equation modelling (SEM) is a statistical technique that might allow for the creation of “research-friendly” clinical constructs from these routine clinical variables and therefore could be an appropriate analytic method to apply more widely to routine clinical data. Objective: SEM was applied to a large data set of routine clinical data developed in East London to model well-established clinical associations. Depression is common among patients with type 2 diabetes, and is associated with poor diabetic control, increased diabetic complications, increased health service utilization, and increased health care costs. Evidence from trial data suggests that integrating psychological treatment into diabetes care can improve health status and reduce costs. Attempting to model these known associations using SEM will test the utility of this technique in routine clinical data sets. Methods: Data were cleaned extensively prior to analysis. SEM was used to investigate associations between depression, diabetic control, diabetic care, mental health treatment, and Accident & Emergency (A&E) use in patients with type 2 diabetes. The creation of the latent variables and the direction of association between latent variables in the model was based upon established clinical knowledge. Results: The results provided partial support for the application of SEM to routine clinical data. Overall, 19% (3106/16,353) of patients with type 2 diabetes had received a diagnosis of depression. In line with known clinical associations, depression was associated with worse diabetic control (β=.034, P<.001) and increased A&E use (β=.071, P<.001). However, contrary to expectation, worse diabetic control was associated with lower A&E use (β=–.055, P<.001) and receipt of mental health treatment did not impact upon diabetic control (P=.39). Receipt of diabetes care was associated with better diabetic control (β=–.072, P<.001), having depression (β=.018, P=.007), and receiving mental health treatment (β=.046, P<.001), which might suggest that comprehensive integrated care packages are being delivered in East London. Conclusions: Some established clinical associations were successfully modelled in a sample of patients with type 2 diabetes in a way that made clinical sense, providing partial evidence for the utility of SEM in routine clinical data. Several issues relating to data quality emerged. Data improvement would have likely enhanced the utility of SEM in this data set

    Estimation of the mixing kernel and the disturbance covariance in IDE-based spatiotemporal systems

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    The integro-difference equation (IDE) is an increasingly popular mathematical model of spatiotemporal processes, such as brain dynamics, weather systems, and disease spread. We present an efficient approach for system identification based on correlation techniques for linear temporal systems that extended to spatiotemporal IDE-based models. The method is derived from the average (over time) spatial correlations of observations to calculate closed-form estimates of the spatial mixing kernel and the disturbance covariance function. Synthetic data are used to demonstrate the performance of the estimation algorithm

    植物CytP450和抗氧化酶对土壤菲、芘暴露的生态毒理响应

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    Maize (Zea mays L.) for the tested plants, meadow brown soil as the soil tested in order to microsomal cytochrome P450 content, superoxide dismutase (SOD), catalase (CAT) and peroxidase enzyme (POD) activity of indicators, the soil phenanthrene and pyrene in response to exposure to eco-toxicological studies. The results show that phenanthrene, pyrene exposure can cause detoxification of plant metabolism and antioxidant defense system of the stress response, caused varying degrees of detoxification of plant metabolism and changes in antioxidant capacity. P450 enzyme activity and low concentrations of phenanthrene and pyrene in a single - relevant exposure concentration (r = 0.834, P &lt;0.01), and phenanthrene and pyrene exposure concentration was negatively correlated compound, saying that Ming Fei, pyrene compound exposed to lead detoxification metabolism of a reduced ability to detoxify the metabolism of plants have synergistic toxic effects; SOD activity and phenanthrene and pyrene in a single exposure concentration was negatively correlated, CAT activity and phenanthrene and pyrene in a single - exposure concentration was positively correlated, POD activity and water solubility of the Philippines positively correlated with the total concentration of pyrene in a negative correlation. SOD, CAT and POD activity and phenanthrene and pyrene were positively related to the concentration of compound exposure, saying that Ming Fei, pyrene complex degree of exposure to lead to reduced oxidative damage, oxidative damage of plants with antagonistic effects .<br /

    The omega-3 fatty acid, DHA, decreases neuronal cell death in association with altered zinc transport

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    Docosahexaenoic acid (DHA) is the major polyunsaturated fatty acid in neuronal cell membranes. We hypothesize that DHA induces a decrease in neuronal cell death through reduced ZnT3 expression and zinc uptake. Exposure of M17 cells to DHA-deficient medium increased the levels of active caspase-3, relative to levels in DHA-replete cells, confirming the adverse effects of DHA deficiency in promoting neuronal cell death. In DHA-treated M17 cells, zinc uptake was 65% less and ZnT3 mRNA and protein levels were reduced in comparison with DHA-depleted cells. We propose that the neuroprotective function of DHA is exerted through a reduction in cellular zinc levels that in turn inhibits apoptosis.<br /

    植物CytP450和抗氧化酶对土壤低浓度菲、芘胁迫的响应

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    Wheat (Triticum aestivum) was chosen to analyze the effect of two polycyclic aromatic hydrocarbons (PAHs), Phenanthrene (PHE) and Pyrene (PY) in brown meadow soil at low concentrations. The effects of PHE and PY were determined by analyzing the changes in activity of Cytochrome P450 (CytP450) and antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Results indicated that both PHE and PY caused changes in activity of CytP450 and the antioxidant enzymes, SOD, POD and CAT. CytP450 activity was significantly stimulated with 1 mg kg-1 of both PHE and PY individually and significantly inhibited with 4 mg kg-1, which showed that pollution stress of PHE or PY can damage the metabolism and detoxification systems of plants. Moreover, as PHE and PY combined at 1 mg kg-1, CytP450 was increased significantly more than when PHE and PY were applied individually, which illustrates obvious synergistic effects. No significant variation were found in activity of SOD in response to individual exposure of PHE or PY in soil, but SOD activity decreased slightly in response to a combined PHE and PY exposure. Great decrease variation was found in CAT and POD activity in response to individual exposure of PHE or PY in soil. No enhanced toxic effects were shown by POD in response to a PHE and PY combined exposure, however CAT showed increased inhibition. From the aspects of metabolism and detoxification as well as antioxidant enzyme activity, our study has provided experimental basis for the pollution diagnosis of PAHs in soils at low concentrations.<br /

    Screening for Learning and Memory Mutations: A New Approach

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    本文详细描述了一种全自动化的行为检测方案。在自然饲养环境/检测环境(24/7)中,我们测量了小鼠针对两个给食器中获得食物的比例与它们在相应给食器停留时长的比例进行匹配的精确性与准确性。该方案是对传统条件性习得(trials-to-acquisition)行为测验设备的改进,可以检测动物时间间隔能力的精确性与准确性,对定时目标选择的相关概率的效果,以及记忆一天中从不同给食器中获得食物次数的精确性与准确性。该压缩系统避免了在整个实验过程中对小鼠的持握操作,可忽略实验者/技术员的实验操作时间,而且可以递送小鼠置入实验环境后,7~9个实验日中全部3组实验流程产生的大量结果。其中,第一个实验流程为单个24小时周期内完成的时间匹配能力的筛查,它对动物的时间、空间估计能力的记忆机制进行精确检测。因此,该系统允许在有限的实验空间、较短的实验周期内,对大量的实验小鼠进行有可能存在的学习记忆能力缺陷进行大规模筛查。此外,该系统运行所依赖的软件可以在公共开放平台获得。</p

    A Proposal for a Three Detector Short-Baseline Neutrino Oscillation Program in the Fermilab Booster Neutrino Beam

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    A Short-Baseline Neutrino (SBN) physics program of three LAr-TPC detectors located along the Booster Neutrino Beam (BNB) at Fermilab is presented. This new SBN Program will deliver a rich and compelling physics opportunity, including the ability to resolve a class of experimental anomalies in neutrino physics and to perform the most sensitive search to date for sterile neutrinos at the eV mass-scale through both appearance and disappearance oscillation channels. Using data sets of 6.6e20 protons on target (P.O.T.) in the LAr1-ND and ICARUS T600 detectors plus 13.2e20 P.O.T. in the MicroBooNE detector, we estimate that a search for muon neutrino to electron neutrino appearance can be performed with ~5 sigma sensitivity for the LSND allowed (99% C.L.) parameter region. In this proposal for the SBN Program, we describe the physics analysis, the conceptual design of the LAr1-ND detector, the design and refurbishment of the T600 detector, the necessary infrastructure required to execute the program, and a possible reconfiguration of the BNB target and horn system to improve its performance for oscillation searches.Comment: 209 pages, 129 figure

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters
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