82 research outputs found
Shape-independent scaling of excitonic confinement in realistic quantum wires
The scaling of exciton binding energy in semiconductor quantum wires is
investigated theoretically through a non-variational, fully three-dimensional
approach for a wide set of realistic state-of-the-art structures. We find that
in the strong confinement limit the same potential-to-kinetic energy ratio
holds for quite different wire cross-sections and compositions. As a
consequence, a universal (shape- and composition-independent) parameter can be
identified that governs the scaling of the binding energy with size. Previous
indications that the shape of the wire cross-section may have important effects
on exciton binding are discussed in the light of the present results.Comment: To appear in Phys. Rev. Lett. (12 pages + 2 figures in postscript
A Classification of Motivation and Behavior Change Techniques Used in Self-Determination Theory-Based Interventions in Health Contexts
While evidence suggests that interventions based on self-determination theory have efficacy in
motivating adoption and maintenance of health-related behaviors, and in promoting adaptive
psychological outcomes, the motivational techniques that comprise the content of these
interventions have not been comprehensively identified or described. The aim of the present
study was to develop a classification system of the techniques that comprise self-determination
theory interventions, with satisfaction of psychological needs as an organizing principle.
Candidate techniques were identified through a comprehensive review of self-determination
theory interventions and nomination by experts. The study team developed a preliminary list of
candidate techniques accompanied by labels, definitions, and function descriptions of each.
Each technique was aligned with the most closely-related psychological need satisfaction
construct (autonomy, competence, or relatedness). Using an iterative expert consensus
procedure, participating experts (N=18) judged each technique on the preliminary list for
redundancy, essentiality, uniqueness, and the proposed link between the technique and basic
psychological need. The procedure produced a final classification of 21 motivation and
behavior change techniques (MBCTs). Redundancies between final MBCTs against techniques
from existing behavior change technique taxonomies were also checked. The classification
system is the first formal attempt to systematize self-determination theory intervention
techniques. The classification is expected to enhance consistency in descriptions of selfdetermination theory-based interventions in health contexts, and assist in facilitating synthesis
of evidence on interventions based on the theory. The classification is also expected to guide
future efforts to identify, describe, and classify the techniques that comprise self-determination
theory-based interventions in multiple domains
Stirring the motivational soup: Within-person latent profiles of motivation in exercise
Background: The purpose of the present study was to use a person-oriented analytical approach to identify latent motivational profiles, based on the different behavioural regulations for exercise, and to examine differences in satisfaction of basic psychological needs (competence, autonomy and relatedness) and exercise behaviour across these motivational profiles. Methods: Two samples, consisting of 1084 and 511 adults respectively, completed exercise-related measures of behavioural regulation and psychological need satisfaction as well as exercise behaviour. Latent profile analyses were used to identify motivational profiles. Results: Six profiles, representing different combinations of regulations for exercise, were found to best represent data in both samples. Some profiles were found in both samples (e.g., low motivation profile, self-determined motivation profile and self-determined with high introjected regulation profile), whereas others were unique to each sample. In line with the Self-Determination Theory, individuals belonging to more self-determined profiles demonstrated higher scores on need satisfaction. Conclusions: The results support the notions of motivation being a multidimensional construct and that people have different, sometimes competing, reasons for engaging in exercise. The benefits of using person-oriented analyses to examine within-person interactions of motivation and different regulations are discussed. © 2017 The Author(s)
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