1,652 research outputs found

    Via Hexagons to Squares in Ferrofluids: Experiments on Hysteretic Surface Transformations under Variation of the Normal Magnetic Field

    Full text link
    We report on different surface patterns on magnetic liquids following the Rosensweig instability. We compare the bifurcation from the flat surface to a hexagonal array of spikes with the transition to squares at higher fields. From a radioscopic mapping of the surface topography we extract amplitudes and wavelengths. For the hexagon--square transition, which is complex because of coexisting domains, we tailor a set of order parameters like peak--to--peak distance, circularity, angular correlation function and pattern specific amplitudes from Fourier space. These measures enable us to quantify the smooth hysteretic transition. Voronoi diagrams indicate a pinning of the domains. Thus the smoothness of the transition is roughness on a small scale.Comment: 17 pages, 14 figure

    Predicting and explaining transtheoretical model stage transitions in relation to condom-carrying behaviour

    Get PDF
    Objectives: The stages of change component of the transtheoretical model has been applied to safe sex behaviours in cross-sectional analyses, but have not yet been subject to prospective analysis. It was predicted that: (a) cross-sectional analyses would demonstrate good discrimination between the stages of change, (b) prospective analyses would allow for the identification of predictors of stage transitions, and (c) implementation intentions would explain progression from the preparation stage. Design: This study employed an experimental longitudinal design. Participants were randomly assigned to the experimental (implementation intention) or control conditions and completed questionnaires at baseline and at 2-months follow up. Methods: 525 adolescents who were broadly representative of the UK population completed questionnaires at baseline and follow up (n = 393) measuring: demographic variables, stage of change, theory of planned behaviour constructs, anticipated regret and moral norm in relation to condom carrying behaviour. The experimental condition completed a self-generated implementation intention to carry condoms at the end of the baseline questionnaire. Results: Discriminant function analyses indicated that the stages of change could be accurately discriminated from one another cross-sectionally and that, longitudinally, the measured variables were able to predict transitions between most stages. Implementation intentions caused people to progress from the preparation stage. Conclusions: Transitions between most stages were reliably predicted thereby providing potential targets for intervention. The brief implementation intention intervention was effective and could easily be utilised and expanded to encompass a broader range of sexual health behaviours.</p

    An Investigation of Coach Behaviors, Goal Motives, and Implementation Intentions as Predictors of Well-Being in Sport

    Get PDF
    The present study aimed to expand upon Smith, Ntoumanis, and Duda’s (2007) research by investigating the influence of coach behaviors and implementation intentions on goal striving in sport. Structural equation modeling analysis with a sample of 108 athletes revealed coach behaviors as predictors of goal motives, which in turn predicted psychological well-being after 8 weeks. Supplementary regression analyses showed no interaction between autonomous goal motives and implementation intentions; however, a synergistic effect was identified for controlled goal motives such that controlled motives furnished with implementation intentions resulted in lower well-being than controlled motives alone. In further analyses, the motives underlying an implementation intention were found to mediate the paths from goal motives to well-being. The findings are discussed in terms of the roles played by goal motives, implementation intentions, and implementation intention motives during goal striving

    Boson-conserving one-nucleon transfer operator in the interacting boson model

    Get PDF
    The boson-conserving one-nucleon transfer operator in the interacting boson model (IBA) is reanalyzed. Extra terms are added to the usual form used for that operator. These new terms change generalized seniority by one unit, as the ones considered up to now. The results obtained using the new form for the transfer operator are compared with those obtained with the traditional form in a simple case involving the pseudo-spin Bose-Fermi symmetry UB(6)UF(12)U^{B}(6) \otimes U^F(12) in its UBF(5)UF(2)U^{BF}(5) \otimes U^F(2) limit. Sizeable differences are found. These results are of relevance in the study of transfer reactions to check nuclear supersymmetry and in the description of (\beta)-decay within IBA.Comment: 13 pages, 1 table, 0 figures. To be published in Phys. Rev.

    Predicting the consumption of foods low in saturated fats among people diagnosed with Type 2 diabetes and cardiovascular disease: the role of planning in the theory of planned behaviour

    Get PDF
    The present study tested the utility of an extended version of the theory of planned behaviour that included a measure of planning, in the prediction of eating foods low in saturated fats among adults diagnosed with Type 2 diabetes and/or cardiovascular disease Participants (N = 184) completed questionnaires assessing standard theory of planned behaviour measures (attitude, subjective norm, and perceived behavioural control) and the additional volitional variable of planning in relation to eating foods low in saturated fats Self-report consumption of foods low insaturated fats was assessed 1 month later In partial support of the theory of planned behaviour, results indicated that attitude and subjective norm predicted intentions to eat foods low in saturated fats and intentions and perceived behavioural control predicted the consumption of foods low in saturated fats As an additional variable, planning predicted the consumption of foods low in saturated fats directly and also mediated the intention-behaviour and perceived behavioural control-behaviour relationships, suggesting an important role for planning as a post-intentional construct determining healthy eating choices. Suggestions are offered for interventions designed to improve adherence to healthy eating recommendations for people diagnosed with these chronic conditions with a specific emphasis on the steps and activities that are required to promote a healthier lifestyle. (C) 2010 Elsevier Ltd. All rights reserve

    Response of a ferrofluid to traveling-stripe forcing

    Full text link
    We observe the dynamics of waves propagating on the surface of a ferrofluid under the influence of a spatially and temporarily modulated field. In particular, we excite plane waves by a travelling lamellar modulation of the magnetization. By this external driving both the wavelength and the propagation velocity of the waves can be controlled. The amplitude of the excited waves exhibits a resonance phenomenon similar to that of a forced harmonic oscillator. Its analysis reveals the dispersion relation of the free surface waves, from which the critical magnetic field for the onset of the Rosensweig instability can be extrapolated

    Enhanced Mucosal Antibody Production and Protection against Respiratory Infections Following an Orally Administered Bacterial Extract

    Get PDF
    Secondary bacterial infections following influenza infection are a pressing problem facing respiratory medicine. Although antibiotic treatment has been highly successful over recent decades, fatalities due to secondary bacterial infections remain one of the leading causes of death associated with influenza. We have assessed whether administration of a bacterial extract alone is sufficient to potentiate immune responses and protect against primary infection with influenza, and secondary infections with either Streptococcus pneumoniae or Klebsiella pneumoniae in mice. We show that oral administration with the bacterial extract, OM-85, leads to a maturation of dendritic cells and B-cells characterized by increases in MHC II, CD86, and CD40, and a reduction in ICOSL. Improved immune responsiveness against influenza virus reduced the threshold of susceptibility to secondary bacterial infections, and thus protected the mice. The protection was associated with enhanced polyclonal B-cell activation and release of antibodies that were effective at neutralizing the virus. Taken together, these data show that oral administration of bacterial extracts provides sufficient mucosal immune stimulation to protect mice against a respiratory tract viral infection and associated sequelae

    Evidence that a very brief psychological intervention boosts weight loss in a weight loss program

    Get PDF
    Reducing morbidity and mortality associated with being overweight is a crucial public health goal. The aim of the present research was to test the efficacy of a very brief psychological intervention (a volitional help sheet) that could be used as an adjunct to standard weight loss programs to support increased weight loss in an overweight sample. Seventy-two overweight participants currently participating in a weight loss program were randomly allocated to either an intervention (volitional help sheet) condition or a control (distracter task) condition. The main outcome measure was weight at 1-month follow-up. Participants in both conditions lost significant amounts of weight, but those in the intervention condition lost significantly more than those in the control condition (d = 0.66). The findings support the efficacy of the volitional help sheet to promote additional weight loss in an overweight sample engaged in a weight loss program. The volitional help sheet therefore represents a very brief, low-cost intervention that could be used to supplement ongoing weight-loss programs

    Downregulation of Anger by Mental Contrasting With Implementation Intentions (MCII)

    Get PDF
    As anger can lead to aggressive behavior aiming at intentionally hurting somebody, the prevention of its destructive consequences with effective emotion regulation strategies is crucial. Two studies tested the idea that mental contrasting with implementation intentions (MCII) interventions would be effective in down-regulating anger. In Study 1, participants who adopted the self-regulation strategy of MCII showed significantly less anger-related negative affect after the anger induction than participants in a control condition, with positive affect staying unaffected. Results from a second study with a control condition plus three self-regulation conditions – a reappraisal, a MCII, and a reappraisal + MCII condition – suggest that participants using MCII were effective in down-regulating anger, irrespective of whether it was supplemented by reappraisal or not. The present research contributes to emotion regulation research by introducing MCII as an effective strategy that can be tailored to satisfy individual emotion regulation demands, such as dealing with experienced anger
    corecore