1,004 research outputs found

    Cumulative and Differential Effects of Early Child Care and Middle Childhood Out-of-School Time on Adolescent Functioning.

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    Effects associated with early child care and out-of-school time (OST) during middle childhood were examined in a large sample of U.S. adolescents (N = 958). Both higher quality early child care AND more epochs of organized activities (afterschool programs and extracurricular activities) during middle childhood were linked to higher academic achievement at age 15. Differential associations were found in the behavioral domain. Higher quality early child care was associated with fewer externalizing problems, whereas more hours of early child care was linked to greater impulsivity. More epochs of organized activities was associated with greater social confidence. Relations between early child care and adolescent outcomes were not mediated or moderated by OST arrangements in middle childhood, consistent with independent, additive relations of these nonfamilial settings

    Top A_FB at the Tevatron vs. charge asymmetry at the LHC in chiral U(1) flavor models with flavored Higgs doublets

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    We consider the top forward-backward (FB) asymmetry at the Tevatron and top charge asymmetry at the LHC within chiral U(1)^\prime models with flavor-dependent U(1)^\prime charges and flavored Higgs fields, which were introduced in the ref. [65]. The models could enhance not only the top forward-backward asymmetry at Tevatron, but also the top charge asymmetry at LHC, without too large same-sign top pair production rates. We identify parameter spaces for the U(1)^\prime gauge boson and (pseudo)scalar Higgs bosons where all the experimental data could be accommodated, including the case with about 125 GeV Higgs boson, as suggested recently by ATLAS and CMS.Comment: 11 pages, 6 figures, figures and discussion adde

    Scalar-mediated ttˉt\bar t forward-backward asymmetry

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    A large forward-backward asymmetry in ttˉt\bar t production, for large invariant mass of the ttˉt\bar t system, has been recently observed by the CDF collaboration. Among the scalar mediated mechanisms that can explain such a large asymmetry, only the t-channel exchange of a color-singlet weak-doublet scalar is consistent with both differential and integrated ttˉt\bar t cross section measurements. Constraints from flavor changing processes dictate a very specific structure for the Yukawa couplings of such a new scalar. No sizable deviation in the differential or integrated ttˉt\bar t production cross section is expected at the LHC.Comment: 22 pages, 1 figure and 2 tables. v2: Corrected Eqs.(50,51,74), adapted Fig.1, Tab.1 and relevant discussions. Extended discussion of top decay and single to

    Understanding and addressing mathematics anxiety using perspectives from education, psychology and neuroscience

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    Mathematics anxiety is a significant barrier to mathematical learning. In this article, we propose that state or on-task mathematics anxiety impacts on performance, while trait mathematics anxiety leads to the avoidance of courses and careers involving mathematics. We also demonstrate that integrating perspectives from education, psychology and neuroscience contributes to a greater understanding of mathematics anxiety in its state and trait forms. Research from cognitive psychology and neuroscience illustrates the effect of state mathematics anxiety on performance and research from cognitive, social and clinical psychology, and education can be used to conceptualise the origins of trait mathematics anxiety and its impact on avoidant behaviour. We also show that using this transdisciplinary framework to consider state and trait mathematics anxiety separately makes it possible to identify strategies to reduce the negative effects of mathematics anxiety. Implementation of these strategies among particularly vulnerable groups, such as pre-service teachers, could be beneficial

    Top quark forward-backward asymmetry in R-parity violating supersymmetry

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    The interaction of bottom squark-mediated top quark pair production, occurring in the R-parity violating minimal supersymmetric standard model (MSSM), is proposed as an explanation of the anomalously large ttˉt\bar{t} forward-backward asymmetry (FBA) observed at the Tevatron. We find that this model can give a good fit to top quark data, both the inclusive and invariant mass-dependent asymmetries, while remaining consistent (at the 2-σ\sigma level) with the total and differential production cross-sections. The scenario is challenged by strong constraints from atomic parity violation (APV), but we point out an extra diagram for the effective down quark-Z vertex, involving the same coupling constant as required for the FBA, which tends to weaken the APV constraint, and which can nullify it for reasonable values of the top squark masses and mixing angle. Large contributions to flavor-changing neutral currents can be avoided if only the third generation of sparticles is light.Comment: 24 pages, 7 figures. v3: included LHC top production cross section data; model still consistent at 2 sigma leve

    Color & Weak triplet scalars, the dimuon asymmetry in BsB_s decay, the top forward-backward asymmetry, and the CDF dijet excess

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    The new physics required to explain the anomalies recently reported by the D0 and CDF collaborations, namely the top forward-backward asymmetry (FBA), the like-sign dimuon charge asymmetry in semileptonic b decay, and the CDF dijet excess, has to feature an amount of flavor symmetry in order to satisfy the severe constrains arising from flavor violation. In this paper we show that, once baryon number conservation is imposed, color & weak triplet scalars with hypercharge Y=1/3Y=1/3 can feature the required flavor structure as a consequence of standard model gauge invariance. The color & weak triplet model can simultaneously explain the top FBA and the dimuon charge asymmetry or the dimuon charge asymmetry and the CDF dijet excess. However, the CDF dijet excess appears to be incompatible with the top FBA in the minimal framework. Our model for the dimuon asymmetry predicts the observed pattern hdâ‰Șhsh_d\ll h_s in the region of parameter space required to explain the top FBA, whereas our model for the CDF dijet anomaly is characterized by the absence of beyond the SM b-quark jets in the excess region. Compatibility of the color & weak triplet with the electroweak constraints is also discussed. We show that a Higgs boson mass exceeding the LEP bound is typically favored in this scenario, and that both Higgs production and decay can be significantly altered by the triplet. The most promising collider signature is found if the splitting among the components of the triplet is of weak scale magnitude.Comment: references added, published versio

    A Critical Review of Anti‐Bullying Programs in North American Elementary Schools

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    BACKGROUNDBullying behavior is a concern among school‐aged youth and anti‐bullying programs have been implemented in schools throughout North America. Most anti‐bullying programs are delivered to adolescent youth because antisocial‐aggressive behaviors are typically associated with this developmental stage. This paper is a review of empirically evaluated school‐based bullying prevention and intervention programs in North American elementary schools.METHODSWe conducted a systematic, critical review of bullying prevention programming. Data were analyzed to determine the study method, intervention components, measurement of bullying, aggression, or peer victimization, outcomes measured, and results.RESULTSOur review resulted in the identification of 10 interventions aimed at youth in grades K‐6 enrolled in North American elementary schools. Effective intervention strategies targeted a variety of bullying behaviors using diverse mechanisms and included a school—and community‐wide approach. Direct outcomes of the reviewed evaluations were centered on bullying, aggression, and victimization. Indirect outcomes of review evaluations included strategies for bystanders, school achievement, perceived school safety, and knowledge or attitudes about bullying.CONCLUSIONSRecommendations for promising practices in effective bullying intervention programming are offered. The review concludes with suggestions for supporting school health staff and in‐service teachers drawn from the body of research, and offers direction for future study.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151360/1/josh12814_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151360/2/josh12814.pd

    Noether Symmetry Approach in "Cosmic Triad" Vector Field Scenario

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    To realize the accelerations in the early and late periods of our universe, we need to specify potentials for the dominant fields. In this paper, by using the Noether symmetry approach, we try to find suitable potentials in the "cosmic triad" vector field scenario. Because the equation of state parameter of dark energy has been constrained in the range of −1.21≀ω≀−0.89-1.21\leq \omega\leq -0.89 by observations, we derive the Noether conditions for the vector field in quintessence, phantom and quintom models, respectively. In the first two cases, constant potential solutions have been obtained. What is more, a fast decaying point-like solution with power-law potential is also found for the vector field in quintessence model. For the quintom case, we find an interesting constraint C~Vpâ€Č=−CVqâ€Č\tilde{C}V_{p}'=-CV_{q}' on the field potentials, where CC and C~\tilde{C} are constants related to the Noether symmetry.Comment: 15 pages, no figures, accepted by Classical and Quantum Gravity

    NLO QCD corrections to tW' and tZ' production in forward-backward asymmetry models

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    We consider Z' and W' models recently proposed to explain the top forward-backward asymmetry at the Tevatron. We present the next-to-leading order QCD corrections to associated production of such vector bosons together with top quarks at the Large Hadron Collider, for centre-of-mass energies of 7 and 8 TeV. The corrections are significant, modifying the total production cross-section by 30-50%. We consider the effects of the corrections on the top and vector-boson kinematics. The results are directly applicable to current experimental searches, for both the ATLAS and CMS collaborations.Comment: 62 pages, 13 figures, 36 tables. v3 Updated to correspond to Journal version and incorporate supplementary materia
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