155 research outputs found

    A retrospective cohort study of predictors and interventions that influence cooperation with mask induction in children

    Full text link
    BackgroundUncooperative pediatric mask induction is linked to perioperative anxiety. Although some risk factors for uncooperative inductions have been reported, there are no large cohort studies that identify intrinsic patient characteristics associated with cooperation.AimThe primary aim was to identify patient characteristics associated with cooperative mask inductions. The secondary aim was to determine whether preoperative interventions were associated with increased cooperation.MethodsThis retrospective cohort study included patients 2- 11 years old and ASA class I- IV who underwent mask induction. Our primary outcome of interest was cooperation with mask induction, which was correlated against the Induction Compliance Checklist. The variables analyzed for association with cooperation were age, sex, ASA class, class of surgery, preferred language, and race. Interventions examined for association with induction cooperation included premedication with midazolam, exposure to distraction technology, parental presence, and the presence of a Child Life Specialist. Multivariate mixed- effects logistic regression was used to assess the relationship between patient characteristics and cooperation. A separate multivariate mixed- effects logistic regression was used to examine the association between preoperative interventions and cooperation.Results9692 patients underwent 23 474 procedures during the study period. 3372 patients undergoing 5980 procedures met inclusion criteria. The only patient characteristic associated with increased cooperation was age (OR 1.20, p- value 0.03). Involvement of Child Life Specialists was associated with increased cooperation (OR 4.44, p- value = 0.048) while parental/guardian presence was associated with decreased cooperation (OR 0.38, p- value = 0.002).ConclusionIn this cohort, increasing age was the only patient characteristic found to be associated with increased cooperation with mask induction. Preoperative intervention by a Child Life Specialists was the sole intervention associated with improved cooperation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162757/2/pan13930.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162757/1/pan13930_am.pd

    Two-station measurement of Rayleigh-wave phase velocities for the Huatung basin, the westernmost Philippine Sea, with OBS : implications for regional tectonics

    Get PDF
    Author Posting. © The Authors, 2009. This article is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 179 (2009): 1859-1869, doi:10.1111/j.1365-246X.2009.04391.x.A broad-band ocean-bottom seismometer (OBS) deployed ~180 km east of Taiwan provides a first glimpse into the upper mantle beneath the westernmost section of the Philippine Sea or the Huatung basin (HB). We measured interstation phase velocities of Rayleigh waves between the OBS and stations on the eastern coast of Taiwan. The phase velocities show smooth variations from 3.8 to 3.9 km s−1 for periods of 25–40 s. In this short period range, phase velocities are comparable to those characterizing the 15–30 Ma Parece-Vela basin of the Philippine Sea. Modelling of the finite-frequency effect proves the validity of the measurement for the average HB. The shear-wave velocity models inverted from the 25 to 40 s dispersion show a velocity at lithospheric depths about 0.1 km s−1 lower than that of the west Philippine Sea, which agrees with the age effect derived from the Pacific pure-path model. Inversions incorporating the less reliable data above 40 s yield a shear velocity <4.0 km s−1 below 150 km, an unrealistic value even for a hotspot plume environment. The seismological evidence, together with the correlation in seafloor depth, suggests that the HB and the Parece-Vela basin may have a similar age. This is at odds with the previous geochronological study suggesting an early-Cretaceous age for the HB. Thermal rejuvenation of the lithosphere was examined as a potential solution to reconciling the two age models.The research is supported by the National Science Council, Taiwan, Republic of China, under grant NSC 96–2745-M-001–005

    Search for electron antineutrino appearance in a long-baseline muon antineutrino beam

    Get PDF
    Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions

    Measurement of neutrino and antineutrino neutral-current quasielasticlike interactions on oxygen by detecting nuclear deexcitation γ rays

    Get PDF
    Neutrino- and antineutrino-oxygen neutral-current quasielastic-like interactions are measured at Super-Kamiokande using nuclear de-excitation γ\gamma-rays to identify signal-like interactions in data from a $14.94 \ (16.35)\times 10^{20}protonsontargetexposureoftheT2Kneutrino(antineutrino)beam.Themeasuredfluxaveragedcrosssectionsonoxygennucleiare protons-on-target exposure of the T2K neutrino (antineutrino) beam. The measured flux-averaged cross sections on oxygen nuclei are \langle \sigma_{\nu {\rm -NCQE}} \rangle = 1.70 \pm 0.17 ({\rm stat.}) ^{+ {\rm 0.51}}_{- {\rm 0.38}} ({\rm syst.}) \times 10^{-38} \ {\rm cm^2/oxygen}withafluxaveragedenergyof0.82GeVand with a flux-averaged energy of 0.82 GeV and \langle \sigma_{\bar{\nu} {\rm -NCQE}} \rangle = 0.98 \pm 0.16 ({\rm stat.}) ^{+ {\rm 0.26}}_{- {\rm 0.19}} ({\rm syst.}) \times 10^{-38} \ {\rm cm^2/oxygen}$ with a flux-averaged energy of 0.68 GeV, for neutrinos and antineutrinos, respectively. These results are the most precise to date, and the antineutrino result is the first cross section measurement of this channel. They are compared with various theoretical predictions. The impact on evaluation of backgrounds to searches for supernova relic neutrinos at present and future water Cherenkov detectors is also discussed

    Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2 x 10(21) Protons on Target

    Get PDF
    The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×102014.7(7.6)\times 10^{20} protons on target in neutrino (antineutrino) mode, 89 νe\nu_e candidates and 7 anti-νe\nu_e candidates were observed while 67.5 and 9.0 are expected for δCP=0\delta_{CP}=0 and normal mass ordering. The obtained 2σ2\sigma confidence interval for the CPCP violating phase, δCP\delta_{CP}, does not include the CPCP-conserving cases (δCP=0,π\delta_{CP}=0,\pi). The best-fit values of other parameters are sin2θ23=0.5260.036+0.032\sin^2\theta_{23} = 0.526^{+0.032}_{-0.036} and Δm322=2.4630.070+0.071×103eV2/c4\Delta m^2_{32}=2.463^{+0.071}_{-0.070}\times10^{-3} \mathrm{eV}^2/c^4.Comment: 9 pages, 6 figure

    Search for light sterile neutrinos with the T2K far detector Super-Kamiokande at a baseline of 295 km

    Get PDF
    We perform a search for light sterile neutrinos using the data from the T2K far detector at a baseline of 295 km, with an exposure of 14.7ð7.6Þ × 1020 protons on target in neutrino (antineutrino) mode. A selection of neutral-current interaction samples is also used to enhance the sensitivity to sterile mixing. No evidence of sterile neutrino mixing in the 3 þ 1 model was found from a simultaneous fit to the charged-current muon, electron and neutral-current neutrino samples. We set the most stringent limit on the sterile oscillation amplitude sin2 θ24 for the sterile neutrino mass splitting Δm241 < 3 × 10−3 eV2=c4

    Measurement of the muon neutrino charged-current cross sections on water, hydrocarbon and iron, and their ratios, with the T2K on-axis detectors

    Get PDF
    We report a measurement of the flux-integrated νμ charged-current cross sections on water, hydrocarbon, and iron in the T2K on-axis neutrino beam with a mean neutrino energy of 1.5 GeV. The measured cross sections on water, hydrocarbon, and iron are σH2OCC=(0.840±0.010(stat.)+0.10−0.08(syst.))×10−38cm2/nucleon, σCHCC=(0.817±0.007(stat.)+0.11−0.08(syst.))×10−38cm2/nucleon, and σFeCC=(0.859±0.003(stat.)+0.12−0.10(syst.))×10−38cm2/nucleon, respectively, for a restricted phase space of induced muons: θμ0.4 GeV/c in the laboratory frame. The measured cross section ratios are σH2OCC/σCHCC=1.028±0.016(stat.)±0.053(syst.)⁠, σFeCC/σH2OCC=1.023±0.012(stat.)±0.058(syst.)⁠, and σFeCC/σCHCC=1.049±0.010(stat.)±0.043(syst.)⁠. These results, with an unprecedented precision for the measurements of neutrino cross sections on water in the studied energy region, show good agreement with the current neutrino interaction models used in the T2K oscillation analyses

    Search for neutral-current induced single photon production at the ND280 near detector in T2K

    Get PDF
    Neutrino neutral-current (NC) induced single photon production is a sub-leading order process for accelerator-based neutrino beam experiments including T2K. It is, however, an important process to understand because it is a background for electron (anti)neutrino appearance oscillation experiments. Here, we performed the first search of this process below 1 GeV using the fine-grained detector at the T2K ND280 off-axis near detector. By reconstructing single photon kinematics from electron-positron pairs, we achieved 95% pure gamma ray sample from 5.738 x 10(20) protons-on-targets neutrino mode data. We do not find positive evidence of NC induced single photon production in this sample. We set the model-dependent upper limit on the cross-section for this process, at 0.114 x 10(-38) cm(2) (90% C.L.) per nucleon, using the J-PARC off-axis neutrino beam with an average energy of similar to 0.6 GeV. This is the first limit on this process below 1 GeV which is important for current and future oscillation experiments looking for electron neutrino appearance oscillation signals

    Search for heavy neutrinos with the T2K near detector ND280

    Get PDF
    International audienceThis paper reports on the search for heavy neutrinos with masses in the range 140<MN<493  MeV/c2 using the off-axis near detector ND280 of the T2K experiment. These particles can be produced from kaon decays in the standard neutrino beam and then subsequently decay in ND280. The decay modes under consideration are N→ℓα±π∓ and N→ℓα+ℓβ-ν(−)(α,β=e,μ). A search for such events has been made using the Time Projection Chambers of ND280, where the background has been reduced to less than two events in the current dataset in all channels. No excess has been observed in the signal region. A combined Bayesian statistical approach has been applied to extract upper limits on the mixing elements of heavy neutrinos to electron-, muon- and tau- flavored currents (Ue2, Uμ2, Uτ2) as a function of the heavy neutrino mass, e.g., Ue2<10-9 at 90% C.L. for a mass of 390  MeV/c2. These constraints are competitive with previous experiments
    corecore