1,299 research outputs found

    W and Z Boson Cross Section and W Asymmetry at CMS

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    We report the measurement of the rates and asymmetries of inclusive and differential production of W and Z vector bosons in pp collision at s\sqrt{s}=7 TeV. The data consists of 36 pb1pb^{-1} collected in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The measured inclusive cross sections are σ(ppWX)×B(Wν)=10.31±0.02(stat.)±0.09(syst.)±0.10(th.)±0.41(lumi.)\sigma(pp\to WX)\times B(W\to \ell\nu) = 10.31 \pm 0.02 (stat.) \pm 0.09 (syst.) \pm 0.10 (th.) \pm 0.41 (lumi.) nb and σ(ppZX)×B(Z)=0.975±0.007(stat.)±0.007(syst.)±0.018(th.)±0.039(lumi.)\sigma(pp\to ZX)\times B(Z\to \ell\ell) = 0.975 \pm 0.007 (stat.) \pm 0.007 (syst.) \pm 0.018 (th.) \pm 0.039 (lumi.) nb. The measured inclusive cross sections and also its ratio of W to Z or W+W^{+} to WW^{-} agree with NNLO QCD cross section calculations and current parton distribution functions (PDFs). The differential production asymmetry of W boson as a function of the lepton pseudorapidity in the final state is also measured and compared with various PDFs.Comment: Proceedings of the DPF-2011 Conference, Providence, RI, August 8-13, 201

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    Department of Computer Science and EngineeringTime series data is everywhere, such as stock data in finance market, the sensor data in factories, or the temperature data in everyday life. Time series data have been studied for a long time to analyze and predict the future behavior. While it is tractable when the sequential data behave as stationary, it becomes difficult to model and predict non-stationary time series. Change point detection is a problem that identify non-stationarity which has been investigated for decades in many different names. Change point detection is a challenging problem because defining a change point decisively and objectively is difficult in nature. In this thesis we are trying to define and find a change point using hypothesis tests based on statistics. Specifically we focus on structural breaks in the covariance structure of Gaussian Processes. Further we propose an online change point detection algorithm, called Confirmatory Bayesian Online Change Point Detection, by leveraging the devised hypothesis tests into the conventional Bayesian online change point detection algorithm.clos

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    Department of ChemistryAlzheimer???s disease (AD) is the most common cause of dementia. The symptoms of AD mainly include short-term memory loss, cognitive defects, and poor judgment, consequently leading to death. Currently 28 million people worldwide are suffering from AD; however, a cure for the disease to retard its initiation and progression has not been developed. Indeed, the discovery of the drug has been very challenging due to the involvement of multiple pathogenic factors in the pathogenesis of AD. For example, the aggregates of amyloidogenic amyloid-b (Ab) peptides are accumulated in the AD-affected brain. Among the aggregates, soluble and structured Ab oligomers have been suggested to be toxic to nerve cells. Additionally, highly concentrated metal ions [e.g., Cu(I/II), Zn(II), Fe(II/III)] are found in senile plaques, composed of Ab aggregates. Disrupted homeostasis of these metal ions would affect neuron signaling, apoptosis, and inflammation. Lastly, reactive oxygen species (ROS) can be overproduced through Fenton-like reactions causing oxidative damage to nucleic acids and cellular organelles. The studies presented in this thesis describe the development of chemical tools able to regulate single or multiple pathogenic component(s). In Chapter 1, an introduction of the hypotheses of AD is described, along with previously reported chemical tools designed to target pathological elements. In Chapter 2, our interdisciplinary studies of new small molecules towards distinct pathological factors, rationally designed via a novel structure-property-directed design strategy, are summarized. Lastly, in Chapter 3, a series of fluorescent sensors for metal ions in living cells is illustrated, which could provide a better understanding of a link of their concentration and compartmentalization to the pathogenesis of AD. Overall, our approaches and findings presented herein would be useful for constructing effective chemical tools and therapeutics for AD, ultimately serving the illumination of complex pathogenesis of the disease in the future.ope

    The Differential cross section distribution of Drell-Yan dielectron pairs in the z boson mass region

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    We report on a measurement of the rapidity distribution, d{sigma}/dy, for Z=Drell-Yan {yields} ee events produced in p{bar p} collisions at {radical}s = 1.96 TeV. The data sample consists of 2.13 fb{sup -1} corresponding to about 160,000 Z/Drell-Yan {yields} ee candidates in the Z boson mass region collected by the Collider Detector at Fermilab. The d{sigma}/dy distribution, which is measured over the full kinematic range for e{sup +}e{sup -} pairs in the invariant mass range 66 < M{sub ee} < 116 GeV/c{sup 2}, is compared with theory predictions. There is good agreement between the data and predictions of Quantum Chromodynamics in Next to Leading Order with the CTEQ6.1M Parton Distribution Functions

    A new analysis technique to measure the W Production Charge Asymmetry at the Tevatron

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    We propose an analysis technique to directly measure W production charge asymmetry from W leptonic decay events at the Tevatron and show the feasibility for new analysis method using Monte Carlo simulations.Comment: 5 pages, 5 figures, to be published in PRD rapid communication

    In Situ-Generated Reactive Oxygen Species in Precharged Titania and Tungsten Trioxide Composite Catalyst Membrane Filters: Application to As(III) Oxidation in the Absence of Irradiation

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    This study demonstrates that in situ-generated reactive oxygen species (ROSs) in prephotocharged TiO₂ and WO₃ (TW) composite particle-embedded inorganic membrane filters oxidize arsenite (As(III)) into arsenate (As(V)) without any auxiliary chemical oxidants under ambient conditions in the dark. TW membrane filters have been charged with UV or simulated sunlight and subsequently transferred to a once-through flow-type system. The charged TW filters can transfer the stored electrons to dissolved O₂, producing ROSs that mediate As(III) oxidation in the dark. Dramatic inhibition of As(V) production with O₂ removal or addition of ROS quenchers indicates an ROS-mediated As(III) oxidation mechanism. Electron paramagnetic spectroscopic analysis has confirmed the formation of the HO₂•/O₂•– pair in the dark. The WO₃ fraction in the TW filter significantly influences the performance of the As(III) oxidation, while As(V) production is enhanced with increasing charging time and solution pH. The As(III) oxidation is terminated when the singly charged TW filter is fully discharged; however, recharging of TW recovers the catalytic activity for As(III) oxidation. The proposed oxidation process using charged TW membrane filters is practical and environmentally benign for the continuous treatment of As(III)-contaminated water during periods of unavailability of sunlight

    In Situ-Generated Reactive Oxygen Species in Precharged Titania and Tungsten Trioxide Composite Catalyst Membrane Filters: Application to As(III) Oxidation in the Absence of Irradiation

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    This study demonstrates that in situ-generated reactive oxygen species (ROSs) in prephotocharged TiO₂ and WO₃ (TW) composite particle-embedded inorganic membrane filters oxidize arsenite (As(III)) into arsenate (As(V)) without any auxiliary chemical oxidants under ambient conditions in the dark. TW membrane filters have been charged with UV or simulated sunlight and subsequently transferred to a once-through flow-type system. The charged TW filters can transfer the stored electrons to dissolved O₂, producing ROSs that mediate As(III) oxidation in the dark. Dramatic inhibition of As(V) production with O₂ removal or addition of ROS quenchers indicates an ROS-mediated As(III) oxidation mechanism. Electron paramagnetic spectroscopic analysis has confirmed the formation of the HO₂•/O₂•– pair in the dark. The WO₃ fraction in the TW filter significantly influences the performance of the As(III) oxidation, while As(V) production is enhanced with increasing charging time and solution pH. The As(III) oxidation is terminated when the singly charged TW filter is fully discharged; however, recharging of TW recovers the catalytic activity for As(III) oxidation. The proposed oxidation process using charged TW membrane filters is practical and environmentally benign for the continuous treatment of As(III)-contaminated water during periods of unavailability of sunlight
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