321 research outputs found

    Seagull and pion-in-flight currents in neutrino-induced 1N1N and 2N2N knockout

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    [Background] The neutrino-nucleus (νA\nu A) cross section is a major source of systematic uncertainty in neutrino-oscillation studies. A precise νA\nu A scattering model, in which multinucleon effects are incorporated, is pivotal for an accurate interpretation of the data. [Purpose] In νA\nu A interactions, meson-exchange currents (MECs) can induce two-nucleon (2N2N) knockout from the target nucleus, resulting in a two-particle two-hole (2p2h) final state. They also affect single nucleon (1N1N) knockout reactions, yielding a one-particle one-hole (1p1h) final state. Both channels affect the inclusive strength. We present a study of axial and vector, seagull and pion-in-flight currents in muon-neutrino induced 1N1N and 2N2N knockout reactions on 12^{12}C. [Method] Bound and emitted nucleons are described as Hartree-Fock wave functions. For the vector MECs, the standard expressions are used. For the axial current, three parameterizations are considered. The framework developed here allows for a treatment of MECs and short-range correlations (SRCs). [Results] Results are compared with electron-scattering data and with literature. The strengths of the seagull, pion-in-flight and axial currents are studied separately and double differential cross sections including MECs are compared with results including SRCs. A comparison with MiniBooNE and T2K data is presented. [Conclusions] In the 1p1h channel, the effects of the MECs tend to cancel each other, resulting in a small effect on the double differential cross section. 2N2N knockout processes provide a small contribution to the inclusive double differential cross section, ranging from the 2N2N knockout threshold into the dip region. A fair agreement with the MiniBooNE and T2K data is reached.Comment: 16 pages, 10 figure

    ABC-training as a new intervention for hazardous alcohol drinking: Two proof-of-principle randomized pilot studies

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    Background and Aims: ABC-training is a new intervention to encourage health behavior change that targets the automatic activation of adaptive beliefs (i.e. automatic inferences). The aim of this proof-of-principle study was to test the effectiveness of web-based ABC-training to change outcome expectancies of alcohol drinking in a sample of hazardous drinkers. Design: One exploratory and one confirmatory experiment with two between-subject conditions (online ABC- and control-training) and assessments at baseline and 1 week later (after three sessions of training). Setting: Participants recruited on Prolific Academic completed the web-based study. Participants: Adults with self-reported hazardous alcohol drinking (Experiment 1: 193 adults, United Kingdom, age mean = 46.7 years; Experiment 2: 282 adults, different nationalities, age mean = 38.3 years). Intervention and Comparator: ABC-training involved completing an online task that required choosing personally relevant alternative behaviors to drinking alcohol in personally relevant antecedent contexts to attain personally important outcomes. Comparator was control-training, in which participants selected both the alternative behaviors and alcohol drinking an equal number of times. Training was completed at baseline, after 3 days and after 1 week. Measurements: Primary outcome was change in automatic and self-reported (negative/positive) outcome expectancies of alcohol drinking from baseline to after 1 week. Secondary outcomes were change in weekly alcohol consumption, self-efficacy, craving and motivation (and approach-alcohol associations in Experiment 1). Moderators were baseline outcome scores, motivation, age and alcohol dependency. Findings: Findings of this study are as follows: stronger increase in negative outcome expectancies after ABC- than control-training (Experiment 1: self-report, 95% confidence interval of difference scores (CIdiff) = [0.04, Inf]; automatic, CIdiff = [0.01, Inf]; Experiment 2: self-report, CIdiff = [0.16, Inf]; automatic, CIdiff = [0.002, Inf]). Stronger reduction in self-reported positive outcome expectancies after ABC- than control-training (Experiment 1: CIdiff = [−Inf, −0.01]; Experiment 2: CIdiff = [−Inf, −0.21]) but mixed findings on automatic positive outcome expectancies (Experiment 1: CIdiff = [−Inf, 0.02]; Experiment 2: CIdiff = [−Inf, −0.001]). Conclusions: ABC-training may change outcome expectancies of alcohol consumption, but testing of clinically relevant effects in other samples is warranted.</p

    Impact of low-energy nuclear excitations on neutrino-nucleus scattering at MiniBooNE and T2K kinematics

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    [Background] Meticulous modeling of neutrino-nucleus interactions is essential to achieve the unprecedented precision goals of present and future accelerator-based neutrino-oscillation experiments. [Purpose] Confront our calculations of charged-current quasielastic cross section with the measurements of MiniBooNE and T2K, and to quantitatively investigate the role of nuclear-structure effects, in particular, low-energy nuclear excitations in forward muon scattering. [Method] The model takes the mean-field (MF) approach as the starting point, and solves Hartree-Fock (HF) equations using a Skyrme (SkE2) nucleon-nucleon interaction. Long-range nuclear correlations are taken into account by means of the continuum random-phase approximation (CRPA) framework. [Results] We present our calculations on flux-folded double differential, and flux-unfolded total cross sections off 12^{12}C and compare them with MiniBooNE and (off-axis) T2K measurements. We discuss the importance of low-energy nuclear excitations for the forward bins. [Conclusions] The CRPA predictions describe the gross features of the measured cross sections. They underpredict the data (more in the neutrino than in the antineutrino case) because of the absence of processes beyond pure quasielastic scattering in our model. At very forward muon scattering, low-energy nuclear excitations (ω<\omega < 50 MeV) account for nearly 50% of the flux-folded cross section.Comment: 8 pages, 9 figures. Version published in Physical Review

    What do implicit measures measure?

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    We identify several ongoing debates related to implicit measures, surveying prominent views and considerations in each debate. First, we summarize the debate regarding whether performance on implicit measures is explained by conscious or unconscious representations. Second, we discuss the cognitive structure of the operative constructs: are they associatively or propositionally structured? Third, we review debates whether performance on implicit measures reflects traits or states. Fourth, we discuss the question of whether a person’s performance on an implicit measure reflects characteristics of the person who is taking the test or characteristics of the situation in which the person is taking the test. Finally, we survey the debate about the relationship between implicit measures and (other kinds of) behavior

    Acute infectieuze (niet Clostridium difficile geassocieerde) diarree bij ouderen

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    Acute –niet antibiotica geassocieerde- diarree is een frequente aandoening die bij ouderen ernstig kan verlopen omwille van de grotere fragiliteit van deze bevolkingsgroep. Acute diarree is meestal van infectieuze oorsprong, en meest frequent te wijten aan een virale infectie. De belangrijkste therapeutische maatregel is het voorzien van voldoende rehydratie. Bij ernstige diarree van bacterie¨ le oorsprong is een antibiotische behandeling aangewezen

    Immobilisation versus immediate mobilisation after intrauterine insemination: randomised controlled trial

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    Objective To evaluate the effectiveness of 15 minutes of immobilisation versus immediate mobilisation after intrauterine insemination

    The formation and evolution of binary systems. III. Low-mass binaries in the Praesepe cluster

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    With the aim of investigating the binary population of the 700 Myr old Praesepe cluster, we have observed 149 G and K-type cluster members using adaptive optics. We detected 26 binary systems with an angular separation ranging from less than 0.08 to 3.3 arcsec (15-600 AU). After correcting for detection biases, we derive a binary frequency (BF) in the logP (days) range from 4.4 to 6.9 of 25.3 +/- 5.4%, which is similar to that of field G-type dwarfs (23.8%, Duquennoy & Mayor 1991). This result, complemented by similar ones obtained for the 2 Myr old star forming cluster IC 348 (Paper II) and the 120 Myr old Pleiades open cluster (Paper I), indicates that the fraction of long-period binaries does not significantly evolve over the lifetime of galactic open clusters. We compare the distribution of cluster binaries to the binary populations of star forming regions, most notably Orion and Taurus, to critically review current ideas regarding the binary formation process. We conclude that it is still unclear whether the lower binary fraction observed in young clusters compared to T associations is purely the result of the early dynamical disruption of primordial binaries in dense clusters or whether it reflects intrinsically different modes of star formation in clusters and associations. We also note that if Taurus binaries result from the dynamical decay of small-N protostellar aggregates, one would predict the existence of a yet to be found dispersed population of mostly single substellar objects in the Taurus cloud.Comment: 10 pages, 3 figure
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