838 research outputs found

    Three-Flavour Neutrino-Mixing Implications of the LSND Result

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    The LSND result is shown to fit into a minimal three-flavour neutrino-mixing scenario capable of describing all known experimental facts provided the large Delta M^2 = m_3^2 - m_2^2 \sim m_3^2 - m_1^2 lies in the range 2.5 x 10^{-1} < Delta M^2 < 3.0 eV^2. In this range the value of P_{\mu\tau} is expected to be about 5% or larger.Comment: 10 pages, 2 eps figures, LaTeX 2.09, revised for Physics Letters

    Steady Combustion Waves Driven by a Recombination Reaction in a Gas Mixture

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    Effect of task failure on intermuscular coherence measures in synergistic muscles

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    The term "task failure" describes the point when a person is not able to maintain the level of force required by a task. As task failure approaches, the corticospinal command to the muscles increases to maintain the required level of force in the face of a decreased mechanical efficacy. Nevertheless, most motor tasks require the synergistic recruitment of several muscles. How this recruitment is affected by approaching task failure is still not clear. The increase in the corticospinal drive could be due to an increase in synergistic recruitment or to overlapping commands sent to the muscles individually. Herein, we investigated these possibilities by combining intermuscular coherence and synergy analysis on signals recorded from three muscles of the quadriceps during dynamic leg extension tasks. We employed muscle synergy analysis to investigate changes in the coactivation of the muscles. Three different measures of coherence were used. Pooled coherence was used to estimate the command synchronous to all three muscles, pairwise coherence the command shared across muscle pairs and residual coherence the command peculiar to each couple of muscles. Our analysis highlights an overall decrease in synergistic command at task failure and an intensification of the contribution of the nonsynergistic shared command

    Is the solar neutrino deficit energy-dependent?

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    All existing measurements of the solar neutrino flux are compared with the predictions of the most recent solar model by Bahcall and Pinsonneault, modified by introducing the hypothesis of neutrino oscillations with mass differences large enough to render energy-independent any quantity observable on earth. It is concluded that the data are consistent with this hypothesis and that, at least for the time being, any energy-dependence of the solar neutrino deficit must be regarded as just an attractive theoretical possibility, but not as a compelling reality.Comment: 6 pages, 1 figure, contributed paper to the XVIII Int. Symposium on Lepton-Photon Interactions, Hamburgh, Germany, 28 July - 1 August 199

    Rates for the reactions antiproton-proton --> pi phi and gamma phi

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    We study antiproton-proton annihilation at rest into πϕ\pi\phi and ÎłÏ•\gamma\phi. Rescattering by K∗‟K+K∗K‟\overline{K^*}K+K^*\overline{K} and ρ+ρ−\rho^{+}\rho^{-} for p‟p→πϕ\overline{p}p\rightarrow\pi\phi states is sizable, of order (0.90 to 2.6)×10−4(0.90\, {\rm to}\,2.6)\times 10^{-4} in the branching ratio, but smaller than experiment. For p‟pâ†’ÎłÏ•\overline{p}p\rightarrow\gamma\phi the rescattering contributions are negligible, but the ÎłÏ•\gamma\phi channel is well explained by a ρϕ\rho\phi intermediate state combined with vector meson dominance.Comment: 12 pages, plain latex, 2 postscript figures available upon request, PSI-PR-93-2

    Testing the performance of a blind burst statistic

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    In this work we estimate the performance of a method for the detection of burst events in the data produced by interferometric gravitational wave detectors. We compute the receiver operating characteristics in the specific case of a simulated noise having the spectral density expected for Virgo, using test signals taken from a library of possible waveforms emitted during the collapse of the core of Type II Supernovae.Comment: 8 pages, 6 figures, Talk given at the GWDAW2002 worksho

    Effects of Somatosensory Stimulation on the Excitability of the Unaffected Hemisphere in Chronic Stroke Patients

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    INTRODUCTION: Somatosensory stimulation of the paretic upper limb enhances motor performance and excitability in the affected hemisphere, and increases activity in the unaffected hemisphere, in chronic stroke patients. We tested the hypothesis that somatosensory stimulation of the paretic hand would lead to changes in excitability of the unaffected hemisphere in these patients, and we investigated the relation between motor function of the paretic hand and excitability of the unaffected hemisphere. METHODS: Transcranial magnetic stimulation was administered to the unaffected hemisphere of nine chronic stroke patients. Patients were submitted to 2-h somatosensory stimulation in the form of median nerve stimulation and control stimulation using a cross-over design. Baseline Jebsen-Taylor test scores were evaluated. Resting motor threshold, intracortical facilitation, short-interval intracortical inhibition, and visual analog scores for attention, fatigue and drowsiness were measured across conditions. RESULTS: Better pre-stimulation baseline motor function was correlated with deeper SICI in the unaffected hemisphere. We found no overt changes in any physiological marker after somatosensory stimulation. There was increased drowsiness in the control session, which may have led to changes in intracortical facilitation. CONCLUSIONS: Our results do not support an overt effect of a single session of somatosensory stimulation of the paretic hand on motor cortical excitability of the unaffected hemisphere as measured by motor threshold, short-interval intracortical inhibition or intracortical facilitation. It remains to be determined if other markers of cortical excitability are modulated by somatosensory stimulation, and whether repeated sessions or lesion location may lead to different effects

    Educational interventions on pregnancy vaccinations during childbirth classes improves vaccine coverages among pregnant women in Palermo’s province

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    Maternal immunization is considered the best intervention in order to prevent influenza infection of pregnant women and influenza and pertussis infection of newborns. Despite the existing recommendations, vaccination coverage rates in Italy remain very low. Starting from August 2018, maternal immunization against influenza and diphtheria-tetanus-pertussis were strongly recommended by the Italian Ministry of Health. We conducted a cross sectional study to estimate the effectiveness of an educational intervention, conducted during childbirth classes in three general hospitals in the Palermo metropolitan area, Italy, on vaccination adherence during pregnancy. To this end, a questionnaire on knowledge, attitudes, and immunization practices was structured and self-administered to a sample of pregnant women attending childbirth classes. Then, an educational intervention on maternal immunization, followed by a counseling, was conducted by a Public Health medical doctor. After 30 days following the interventions, the adherence to the recommended vaccinations (influenza and pertussis) was evaluated. At the end of the study 326 women were enrolled and 201 responded to the follow-up survey. After the intervention, among the responding pregnant women 47.8% received influenza vaccination (+44.8%), 57.7% diphtheria-tetanus-pertussis vaccination (+50.7%) and 64.2% both the recommended vaccinations (+54.8%). A significant association was found between pregnant women that received at least one vaccination during pregnancy and higher educational level (graduation degree/master’s degree), employment status (employed part/full-time) and influenza vaccination adherence during past seasons (at least one during last five years). The implementation of vaccination educational interventions, including counseling by healthcare professionals (HCPs), on maternal immunization during childbirth courses improved considerably the vaccination adherence during pregnancy
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