422 research outputs found
A longitudinal examination of coach and peer motivational climates in youth sport: Implications for moral attitudes, well-being, and behavioral investment.
Embedded in achievement goal theory (Ames, 1992; Meece, Anderman & Anderman, 2006), this study examined how perceptions of coach and peer motivational climate in youth sport predicted moral attitudes, emotional well-being, and indices of behavioral investment in a sample of British adolescents competing in regional leagues. Adopting a longitudinal perspective, measures were taken at the middle and the end of a sport season, as well as at the beginning of the following season. Multilevel modeling analyses showed that perceptions of task-involving peer and coach climates were predictive of more adaptive outcomes compared to perceptions of ego-involving peer and coach climates. Predictive effects differed as a function of time and outcome variable under investigation. The results indicate the importance of considering peer influence in addition to coach influence when examining motivational climate in youth sport
Psychological Need Thwarting in the Sport Context: Assessing the Darker Side of Athletic Experience
Research in self-determination theory (Ryan & Deci, 2002) has shown that satisfacÂtion of autonomy, competence, and relatedness needs in sport contexts is associated with enhanced engagement, performance, and well-being. This article outlines the initial development of a multidimensional measure designed to assess psychologiÂcal need thwarting, an under-studied area of conceptual and practical importance. Study 1 generated a pool of items designed to tap the negative experiential state that occurs when athletes perceive their needs for autonomy, competence, and relatedness to be actively undermined. Study 2 tested the factorial structure of the questionnaire using confirmatory factor analysis. The supported model comprised 3 factors, which represented the hypothesized interrelated dimensions of need thwarting. The model was refined and cross-validated using an independent sample in Study 3. Overall, the psychological need thwarting scale (PNTS) demonstrated good content, factorial, and predictive validity, as well as internal consistency and invariance across gender, sport type, competitive level, and competitive experiÂence. The conceptualization of psychological need thwarting is discussed, and suggestions are made regarding the use of the PNTS in research pertaining to the darker side of sport participation
Self-determination theory and diminished functioning: the role of interpersonal control and psychological need thwarting
Drawing from self-determination theory (Ryan & Deci, 2002), three studies explored the social-environmental conditions that satisfy versus thwart psychological needs and, in turn, impact psychological functioning and well/ill-being. In cross-sectional Studies 1 and 2, structural equation modeling analyses supported latent factor models in which need satisfaction was predicted by athletesâ perceptions of autonomy support and need thwarting was better predicted by perceived coach control. Athletesâ perceptions of need satisfaction predicted positive outcomes associated with sport participation (vitality and positive affect) whereas perceptions of need thwarting more consistently predicted maladaptive outcomes (disordered eating, burnout, depression, negative affect, and physical symptoms). In addition, athletesâ perceptions of psychological need thwarting were significantly associated with perturbed physiological arousal (elevated levels of secretory immunoglobulin A) prior to training. The final study involved the completion of a diary and supported the relations observed in the cross-sectional studies at a daily level. These findings have important implications for the operationalization and measurement of interpersonal styles and psychological needs
Thomas-Fermi Approximation for a Condensate with Higher-order Interactions
We consider the ground state of a harmonically trapped Bose-Einstein
condensate within the Gross-Pitaevskii theory including the effective-range
corrections for a two-body zero-range potential. The resulting non-linear
Schr\"odinger equation is solved analytically in the Thomas-Fermi approximation
neglecting the kinetic energy term. We present results for the chemical
potential and the condensate profiles, discuss boundary conditions, and compare
to the usual Thomas-Fermi approach. We discuss several ways to increase the
influence of effective-range corrections in experiment with magnetically
tunable interactions. The level of tuning required could be inside experimental
reach in the near future.Comment: 8 pages, RevTex4 format, 5 figure
Three-body recombination rates near a Feshbach resonance within a two-channel contact interaction model
We calculate the three-body recombination rate into a shallow dimer in a gas
of cold bosonic atoms near a Feshbach resonance using a two-channel contact
interaction model. The two-channel model naturally describes the variation of
the scattering length through the Feshbach resonance and has a finite effective
range. We confront the theory with the available experimental data and show
that the two-channel model is able to quantitatively describe the existing
data. The finite effective range leads to a reduction of the scaling factor
between the recombination minima from the universal value of 22.7. The
reduction is larger for larger effective ranges or, correspondingly, for
narrower Feshbach resonances.Comment: 9 pages, 7 figure
N-body Efimov states of trapped bosons
We demonstrate the possibility of existence of meta-stable N-body Efimov
states in trapped Bose systems with large scattering length. We calculate
spectra of trapped systems of N=3,4,5,6, and 7 bosons using a stochastic
variational method with a restricted correlated Gaussian basis. For each system
the calculations reveal a series of Efimov states where the energy and the
r.m.s. radius exhibit the characteristic exponential dependence upon the state
number. We also estimate the contribution of these states to the recombination
rate of Bose-Einstein condensates
One More Awareness Gap? The BehaviourâImpact Gap Problem
Preceding research has made hardly any attempt to measure the ecological impacts of pro-environmental behaviour in an objective way. Those impacts were rather supposed or calculated. The research described herein scrutinized the ecological impact reductions achieved through pro-environmental behaviour and raised the question how much of a reduction in carbon footprint can be achieved through voluntary action without actually affecting the socio-economic determinants of life. A survey was carried out in order to measure the difference between the ecological footprint of âgreenâ and âbrownâ consumers. No significant difference was found between the ecological footprints of the two groupsâsuggesting that individual pro-environmental attitudes and behaviour do not always reduce the environmental impacts of consumption. This finding resulted in the formulation of a new proposition called the BIG (behaviourâimpact gap) problem, which is an interesting addition to research in the field of environmental awareness gaps
Ca(2+ )binding to complement-type repeat domains 5 and 6 from the low-density lipoprotein receptor-related protein
BACKGROUND: The binding of ligands to clusters of complement-type repeat (CR)-domains in proteins of the low-density lipoprotein receptor (LDLR) family is dependent on Ca(2+ )ions. One reason for this cation requirement was identified from the crystal structure data for a CR-domain from the prototypic LDLR, which showed the burial of a Ca(2+ )ion as a necessity for correct folding and stabilization of this protein module. Additional Ca(2+ )binding data to other CR-domains from both LDLR and the LDLR-related protein (LRP) have suggested the presence of a conserved Ca(2+ )cage within CR-domains from this family of receptors that function in endocytosis and signalling. RESULTS: We have previously described the binding of several ligands to a fragment comprising the fifth and the sixth CR-domain (CR56) from LRP, as well as qualitatively described the binding of Ca(2+ )ions to this CR-domain pair. In the present study we have applied the rate dialysis method to measure the affinity for Ca(2+), and show that CR56 binds 2 Ca(2+ )ions with an average affinity of K(D )= 10.6 microM, and there is no indication of additional Ca(2+ )binding sites within this receptor fragment. CONCLUSIONS: Both CR-domains of CR56 bind a single Ca(2+ )ion with an affinity of 10.6 microM within the range of affinities demonstrated for several other CR-domains
Resonant Five-body Recombination in an Ultracold Gas of Bosonic Atoms
We combine theory and experiment to investigate five-body recombination in an
ultracold gas of atomic cesium at negative scattering length. A refined
theoretical model, in combination with extensive laboratory tunability of the
interatomic interactions, enables the five-body resonant recombination rate to
be calculated and measured. The position of the new observed recombination
feature agrees with a recent theoretical prediction and supports the prediction
of a family of universal cluster states at negative that are tied to an
Efimov trimer.Comment: 14 pages, 5 figure
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