4,685 research outputs found

    Food-induced fatal anaphylaxis: from epidemiological data to general prevention strategies

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    BACKGROUND: Anaphylaxis hospitalisations are increasing in many countries, in particular for medication and food triggers in young children. Food-related anaphylaxis remains an uncommon cause of death, but a significant proportion of these are preventable. AIM: To review published epidemiological data relating to food-induced anaphylaxis and potential risk factors of fatal and/or near-fatal anaphylaxis cases, in order to provide strategies to reduce the risk of severe adverse outcomes in food anaphylaxis. METHODS: We identified 32 published studies available in MEDLINE (1966-2017), EMBASE (1980-2017), CINAHL (1982-2017), using known terms and synonyms suggested by librarians and allergy specialists. RESULTS: Young adults with a history of asthma, previously known food allergy particularly to peanut/tree nuts are at higher risk of fatal anaphylaxis reactions. In some countries, cow's milk and seafood/fish are also becoming common triggers of fatal reactions. Delayed adrenaline injection is associated with fatal outcomes, but timely adrenaline alone may be insufficient. There is still a lack of evidence regarding the real impact of these risk factors and co-factors (medications and/or alcohol consumption, physical activities, and mast cell disorders). CONCLUSIONS: General strategies should include optimization of the classification and coding for anaphylaxis (new ICD 11 anaphylaxis codes), dissemination of international recommendations on the treatment of anaphylaxis, improvement of the prevention in food and catering areas and, dissemination of specific policies for allergic children in schools. Implementation of these strategies will involve national and international support for ongoing local efforts in relationship with networks of centres of excellence to provide personalized management (which might include immunotherapy) for the most at-risk patients. This article is protected by copyright. All rights reserved

    Search for R-parity Violating Supersymmetry in Dimuon and Four-Jets Channel

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    We present results of a search for R-parity-violating decay of the neutralino chi_1^0, taken to be the Lightest Supersymmetric Particle. It is assumed that this decay proceeds through one of the lepton-number violating couplings lambda-prime_2jk (j=1,2; k=1,2,3). This search is based on 77.5 pb-1 of data, collected by the D0 experiment at the Fermilab Tevatron in ppbar collisions at a center of mass energy of 1.8 TeV in 1992-1995.Comment: 10 pages, 3 figure

    Search for New Physics Using Quaero: A General Interface to D0 Event Data

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    We describe Quaero, a method that i) enables the automatic optimization of searches for physics beyond the standard model, and ii) provides a mechanism for making high energy collider data generally available. We apply Quaero to searches for standard model WW, ZZ, and ttbar production, and to searches for these objects produced through a new heavy resonance. Through this interface, we make three data sets collected by the D0 experiment at sqrt(s)=1.8 TeV publicly available.Comment: 7 pages, submitted to Physical Review Letter

    Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV

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    We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure

    Search for charged Higgs bosons decaying to top and bottom quarks in ppbar collisions

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    We describe a search for production of a charged Higgs boson, q \bar{q'} -> H^+, reconstructed in the t\bar{b} final state in the mass range 180 <= M_{H^+} <= 300 GeV. The search was undertaken at the Fermilab Tevatron collider with a center-of-mass energy sqrt{s} = 1.96 TeV and uses 0.9 fb^{-1} of data collected with the D0 detector. We find no evidence for charged Higgs boson production and set upper limits on the production cross section in the Types I, II and III two-Higgs-doublet models (2HDMs). An excluded region in the (M_{H^+},tan\beta) plane for Type I 2HDM is presented.Comment: Submitted to Phys. Rev. Letter

    Simultaneous measurement of the ratio B(t->Wb)/B(t->Wq) and the top quark pair production cross section with the D0 detector at sqrt(s)=1.96 TeV

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    We present the first simultaneous measurement of the ratio of branching fractions, R=B(t->Wb)/B(t->Wq), with q being a d, s, or b quark, and the top quark pair production cross section sigma_ttbar in the lepton plus jets channel using 0.9 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV collected with the D0 detector. We extract R and sigma_ttbar by analyzing samples of events with 0, 1 and >= 2 identified b jets. We measure R = 0.97 +0.09-0.08 (stat+syst) and sigma_ttbar = 8.18 +0.90-0.84 (stat+syst)} +/-0.50 (lumi) pb, in agreement with the standard model prediction.Comment: submitted to Phys.Rev.Letter

    Search for dark photons from supersymmetric hidden valleys

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    We search for a new light gauge boson, a dark photon, with the D0 experiment. In the model we consider, supersymmetric partners are pair produced and cascade to lightest neutralinos that can decay into the hidden sector state plus either a photon or a dark photon. The dark photon decays through its mixing with a photon into fermion pairs. We therefore investigate a previously unexplored final state that contains a photon, two spatially close leptons, and large missing transverse energy. We do not observe any evidence for dark photons and set a limit on their production.Comment: submitted to PR

    Observation of ZZ production in ppbar collisions at sqrt(s) = 1.96 TeV

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    We present an observation for ZZ -> l+l-l'+l'- (l, l' = e or mu) production in ppbar collisions at a center-of-mass energy of sqrt(s) = 1.96 TeV. Using 1.7 fb-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider, we observe three candidate events with an expected background of 0.14 +0.03 -0.02 events. The significance of this observation is 5.3 standard deviations. The combination of D0 results in this channel, as well as in ZZ -> l+l-nunubar, yields a significance of 5.7 standard deviations and a combined cross section of sigma(ZZ) = 1.60 +/- 0.63 (stat.) +0.16 -0.17 (syst.) pb.Comment: 7 pages, 1 figure, 2 tables Modified slightly following review proces

    Search for CP violation in semileptonic Bs decays

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    We have performed a search for CP violation in a sample of Bs -> Ds mu X decays corresponding to 55~fb1^{-1} of proton-antiproton collisions collected by the D0 detector in Run~II at the Fermilab Tevatron Collider. New physics in Bs0B_s^0 mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for Bs0Bˉs0B_s^0\to \bar{B}_s^0 oscillated states versus that for Bˉs0Bs0\bar{B}_s^0\to {B}_s^0. A fit to the decay-time distributions of the Bs0/Bˉs0B_s^0/\bar{B}_s^0 candidates yields the flavor-specific asymmetry afss=[1.7±9.1(stat)1.5+1.4(syst)]×103a_{fs}^{s}=[-1.7\pm 9.1\mathrm{(stat)}^{+1.4}_{-1.5}\mathrm{(syst)}] \times 10^{-3}, which excludes CP violation due to new physics within the experimental sensitivity.Comment: published in Phys. Rev.

    Measurement of the forward-backward charge asymmetry and extraction of sin^2Theta^{eff}_W in ppbar -> Z/\gamma^{*}+X -> e+e+X events produced at \sqrt{s}=1.96 TeV

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    We present a measurement of the forward-backward charge asymmetry (AFBA_{FB}) in ppˉZ/γ+Xe+e+Xp\bar{p} \to Z/\gamma^{*}+X \to e^+e^-+X events at a center-of-mass energy of 1.96 TeV using 1.1 fb1^{-1} of data collected with the D0 detector at the Fermilab Tevatron collider. AFBA_{FB} is measured as a function of the invariant mass of the electron-positron pair, and found to be consistent with the standard model prediction. We use the AFBA_{FB} measurement to extract the effective weak mixing angle sin2ThetaWeff=0.2327±0.0018(stat.)±0.0006(syst.)sin^2Theta^{eff}_W = 0.2327 \pm 0.0018 (stat.) \pm 0.0006 (syst.).Comment: 7 Pages, 1 Figure, 3 Tables, Accepted by Phys. Rev. Let
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