472 research outputs found

    Internal-quantum-state engineering using magnetic fields

    Get PDF
    We present a general, semi-classical theory describing the interaction of an atom with an internal state consisting of a number of degenerate energy levels with static and oscillating magnetic fields. This general theory is applied to the 3P2 metastable energy level of neon to determine the dynamics of the populations and coherences that are formed due to the interaction. Through these calculations we demonstrate how the interaction may be used for the internal state preparation of an atom

    Testing a model of antecedents and consequences of defensive pessimism and self-handicapping in school physical education

    Get PDF
    There has been very limited research on the use of self-worth protection strategies in the achievement context of school physical education (PE). Thus, this study aimed to examine some antecedents and consequences of defensive pessimism and self-handicapping. The sample comprised 534 (females n = 275; males n = 259) British pupils recruited from two schools who responded to established questionnaires. Results of structural equation modelling analysis indicated that self-handicapping and defensive pessimism were positively predicted by fear of failure and negatively predicted by competence valuation. In addition, defensive pessimism was negatively predicted by physical self-concept. In turn, defensive pessimism negatively predicted enjoyment in PE and intentions to participate in future optional PE programs. Self-handicapping did not predict enjoyment or intentions. Results from multi-sample structural equation modelling showed the specified model to be largely invariant across males and females. The findings indicate that although both strategies aim to protect one’s self-worth, some of their antecedents and consequences in PE may differ

    Maturity associated variance in physical activity and health-related quality of life in adolescent females. A mediated effects model

    Get PDF
    BACKGROUND. This study tested a mediated effects model of psychological and behavioral adaptation to puberty within the context of physical activity (PA). METHODS. Biological maturity status, physical self-concept, PA, and health-related quality of life (HRQoL) were assessed in 222 female British year 7 to 9 pupils (mean age = 12.7 years, SD = .8). RESULTS. Structural equation modeling using maximum likelihood estimation and bootstrapping procedures supported the hypothesized model. Maturation status was inversely related to perceptions of sport competence, body attractiveness, and physical condition; and indirectly and inversely related to physical self-worth, PA, and HRQoL. Examination of the bootstrap-generated bias-corrected confidence intervals representing the direct and indirect paths between suggested that physical self-concept partially mediated the relations between maturity status and PA, and maturity status and HRQoL. CONCLUSIONS. Evidence supports the contention that perceptions of the physical self partially mediate relations maturity, PA, and HRQoL in adolescent females

    Comparison of Electron-Atom Collision Parameters for S to P Transitions under Reversal of Energy Transfer

    Get PDF
    Inelastic and superelastic electron scattering from the optically prepared 32P3/2 state of sodium has enabled atomic collision parameters to be deduced for the 4S-3P deexcitation and the 3S-3P excitation processes. These data are compared with convergent close coupling and second order distorted wave Born calculations. For excitation, both theories agree with experiment, whereas for deexcitation the close coupling theory is in better agreement. A long-standing proposal relating to the sign of the transferred angular momentum is not supported

    Comparison of Electron-Atom Collision Parameters for S to P Transitions under Reversal of Energy Transfer

    Get PDF
    Inelastic and superelastic electron scattering from the optically prepared 32P3/2 state of sodium has enabled atomic collision parameters to be deduced for the 4S-3P deexcitation and the 3S-3P excitation processes. These data are compared with convergent close coupling and second order distorted wave Born calculations. For excitation, both theories agree with experiment, whereas for deexcitation the close coupling theory is in better agreement. A long-standing proposal relating to the sign of the transferred angular momentum is not supported

    A Scoping Review of the Literature on Trauma Cue-Induced Drug Craving in Substance Users with Trauma Histories or PTSD

    Get PDF
    Among trauma-exposed individuals, substances may be used as a means of obtaining symptom relief following exposure to trauma reminders. Repeated pairing of trauma cues with substance use may lead to the development of classically conditioned craving to trauma cues. Conditioned craving following cue exposure can be studied in-lab using the cue-reactivity paradigm. To map cue-reactivity research conducted with trauma-exposed substance users, we aimed to synthesize research which studied our population of interest, used a cue-reactivity paradigm, and measured craving as an outcome. Three databases were searched using relevant keywords. Twenty-eight studies met our criteria. Four key 19 themes are discussed in our review of these scoped studies—(1) craving as an outcome; (2) methodological subtypes across paradigms; (3) affect as an additional outcome or as a mediator of cue-induced craving; and (4) cue-reactivity paradigms as an intervention outcome assessment tool. Overall, there is strong evidence for cue-reactivity paradigms as a useful means of eliciting craving in response to trauma cues. Our scoping review suggests the need for a meta-analysis to determine the magnitude of the trauma cue-induced craving effect in substance users with trauma histories, and to determine significant moderators (e.g., PTSD symptom severity) and mediators of this effect (e.g., negative affect)

    Associations between meeting combinations of 24-h movement guidelines and health-related quality of life in children from 12 countries

    Get PDF
    OBJECTIVES: To examine whether meeting vs not meeting movement/non-movement guidelines (moderate-to-vigorous physical activity [MVPA], screen time, sleep duration), and combinations of these recommendations, are associated with health-related quality of life (HRQoL) in children from 12 countries in five major geographic regions of the world and explore whether the associations vary by study site.STUDY DESIGN: Observational, multinational cross-sectional study.METHODS: This study included 6106 children aged 9-11 years from sites in Australia, Brazil, Canada, China, Colombia, Finland, India, Kenya, Portugal, South Africa, the United Kingdom, and the United States. Participants completed the KIDSCREEN-10 to provide a global measure of their HRQoL. Sleep duration and MVPA were assessed using 24-h accelerometry. Screen time was assessed through self-report. Meeting the recommendations was defined as ≥60 min/day for MVPA, ≤2 h/day for screen time, and between 9 and 11 h/night for sleep duration. Age, sex, highest parental education, unhealthy diet pattern score, and body mass index z-score were included as covariates in statistical models.RESULTS: In the full sample, children meeting the screen time recommendation, the screen time + sleep recommendation, and all three recommendations had significantly better HRQoL than children not meeting any of these guidelines. Differences in HRQoL scores between sites were also found within combinations of movement/non-movement behaviors. For example, while children in Australia, Canada, and USA self-reported better HRQoL when meeting all three recommendations, children in Kenya and Portugal reported significantly lower HRQoL when meeting all three recommendations (relative to not meeting any).CONCLUSIONS: Self-reported HRQoL is generally higher when children meet established movement/non-movement recommendations. However, differences between study sites also suggest that interventions aimed at improving lifestyle behaviors and HRQoL should be locally and culturally adapted.</p

    The Cuprous-Cupric Complex in Hydrochloric Acid Solution

    Get PDF
    In the process described by Diehl and Brouns (1) for the direct determination of copper in bronze by electrodeposition from hydrochloric acid solution using hydroxylammonium chloride as anodic depolarizer and controlling the cathode potential automatically (3), the sample of bronze is dissolved in hydrochloric acid by the dropwise addition of nitric acid or of hydrogen peroxide. Subsequently the solution is diluted and electrolyzed, the cathode reaction being· first the reduction of cupric ion to the chlorocuprous ion, CuCl3==, and then the deposition of copper. The time of electrolysis can be materially shortened if the first reduction is effected chemically, by the addition of hydrocxylammonium chloride or of stannous chloride. If the reducing agent be added to the solution before it is diluted, that is, to a fairly concentrated hydrochloric acid solution, the solution turns dark brown or black, the color being due to some material in solution which disappears on dilution. It became of interest to learn more of this dark colored solution, particularly since it was observed that a small amount of antimony did or did not deposit with the copper depending on whether the reduction was made before or after the dilution
    • …
    corecore