Laser beam self-focusing in the atmosphere

We propose to exploit a self-focusing effect in the atmosphere to assist delivering powerful laser beams from orbit to the ground. We demonstrate through numerical modeling that when the self-focusing length is comparable with the atmosphere height the spot size on the ground can be reduced well below the diffraction limits without beam quality degradation. The density variation suppresses beam filamentation and provides the self-focusing of the beam as a whole. The use of light self-focusing in the atmosphere can greatly relax the requirements for the orbital optics and ground receivers.

The effect of age, gender and attitudes on self-regulation in driving

Self-regulation in driving has primarily been studied as a precursor to driving cessation in older people, who minimise driving risk and compensate for physical and cognitive decline by avoiding driving in challenging circumstances, e.g. poor weather conditions, in the dark and at busy times. This research explores whether other demographic groups of drivers adopt self-regulatory behaviours and examines the effects of affective and instrumental attitudes on self-regulation across the lifespan. Quantitative data were collected from 395 drivers. Women were significantly more likely than men to engage in self-regulation, and to be negatively influenced by their emotions (affective attitude). A quadratic effect of age on self-regulation was determined such that younger and older drivers reported higher scores for self-regulation than middle-years' drivers. However, this effect was affected by experience such that when experience was controlled for, self-regulation increased with age. Nevertheless, anxious driving style and negative affective attitude were independent predictors of self-regulation behaviours. Results suggest that self-regulation behaviours are present across the driving lifespan and may occur as a result of driving anxiety or low confidence rather than as an effect of ageing.

Upconversion assisted self-pulsing in a high-concentration erbium doped fiber laser

We report results on experimental and theoretical characterisation of self-pulsing in high concentration erbium doped fibre laser which is free from erbium clusters. Unlike previous models of self-pulsing accounting for pair-induced quenching (PIQ) on the clustered erbium ions, new model has been developed with accounting for statistical nature of the excitation migration and upconversion and resonance-like pumpto-signal intensity noise transfer. The obtained results are in a good agreement with the experimental data.

Self-explanation in adaptive systems

The behaviour of self adaptive systems can be emergent. The difficulty in predicting the system's behaviour means that there is scope for the system to surprise its customers and its developers. Because its behaviour is emergent, a self-adaptive system needs to garner confidence in its customers and it needs to resolve any surprise on the part of the developer during testing and mainteinance. We believe that these two functions can only be achieved if a self-adaptive system is also capable of self-explanation. We argue a self-adaptive system's behaviour needs to be explained in terms of satisfaction of its requirements. Since self-adaptive system requirements may themselves be emergent, a means needs to be found to explain the current behaviour of the system and the reasons that brought that behaviour about. We propose the use of goal-based models during runtime to offer self-explanation of how a system is meeting its requirements, and why the means of meeting these were chosen. We discuss the results of early experiments in self-explanation, and set out future work. © 2012 C.E.S.A.M.E.S.

Global and physical self-esteem and body dissatisfaction as mediators of the relationship between weight status and being a victim of bullying

Research has found evidence of a link between being overweight or obese and bullying/peer victimisation, and also between obesity and adjustment problems such as low self-esteem and body dissatisfaction. Studies have also found that adjustment problems can put children at an increased risk of being bullied over time. However, to date the factors that place overweight or obese children at risk of being bullied have been poorly elucidated. Self-report data were collected from a sample of 11-14 year olds (N=376) about their weight status, about their experiences of three different types of bullying (Verbal, Physical and Social), their global self-worth, self-esteem for physical appearance, and body dissatisfaction. Overweight or obese children reported experiencing significantly more verbal and physical (but not social) bullying than their non-overweight peers. Global self-worth, self-esteem for physical appearance and body dissatisfaction each fully mediated the paths between weight status and being a victim of bullying.

The spatial distribution of self-employment in India:evidence from semi-parametric geoadditive models

The spatial distribution of self-employment in India: evidence from semiparametric geoadditive models, Regional Studies. The entrepreneurship literature has rarely considered spatial location as a micro-determinant of occupational choice. It has also ignored self-employment in developing countries. Using Bayesian semiparametric geoadditive techniques, this paper models spatial location as a micro-determinant of self-employment choice in India. The empirical results suggest the presence of spatial occupational neighbourhoods and a clear north–south divide in self-employment when the entire sample is considered; however, spatial variation in the non-agriculture sector disappears to a large extent when individual factors that influence self-employment choice are explicitly controlled. The results further suggest non-linear effects of age, education and wealth on self-employment.

The role of self-regulation in developing leaders:a longitudinal field experiment

A longitudinal field experiment examined a leader self-regulation intervention in teams engaged in a Business Strategy Module (BSM) of a University course. The BSM, which is an integral part of the degree programme, involved teams of four or five individuals, under the direction of a leader, working on a (simulated) car manufacturing task over a period of 24. weeks. Various aspects of team performance contributed towards module assessment. All leaders received multi-source feedback of leader task-relevant capabilities (from the leader, followers and module tutor). Leaders were randomly allocated into a self-regulation intervention (15 leaders, 46 followers) or control (25 leaders, 109 followers) conditions. The intervention, which was run by an independent coach, was designed to improve leaders' use of self-regulatory processes to aid the development of task-relevant leadership competencies. Survey data was collected from the leaders and followers (on three occasions: pre- and two post-test intervention), team financial performance (three occasions: post-test) and a final team report (post-test). The leader self-regulation intervention led to increased followers' ratings of leader's effectiveness, higher team financial performance and higher final team grade compared to the control (non-intervention) condition. Furthermore, the benefits of the self-regulation intervention were mediated by leaders' attaining task-relevant competencies. © 2013.

Self-explanation in adaptive systems based on runtime goal-based models

The behaviour of self adaptive systems can be emergent, which means that the system’s behaviour may be seen as unexpected by its customers and its developers. Therefore, a self-adaptive system needs to garner confidence in its customers and it also needs to resolve any surprise on the part of the developer during testing and maintenance. We believe that these two functions can only be achieved if a self-adaptive system is also capable of self-explanation. We argue a self-adaptive system’s behaviour needs to be explained in terms of satisfaction of its requirements. Since self-adaptive system requirements may themselves be emergent, we propose the use of goal-based requirements models at runtime to offer self-explanation of how a system is meeting its requirements. We demonstrate the analysis of run-time requirements models to yield a self-explanation codified in a domain specific language, and discuss possible future work.

Self-affinity in financial asset returns

We test for departures from normal and independent and identically distributed (NIID) log returns, for log returns under the alternative hypothesis that are self-affine and either long-range dependent, or drawn randomly from an L-stable distribution with infinite higher-order moments. The finite sample performance of estimators of the two forms of self-affinity is explored in a simulation study. In contrast to rescaled range analysis and other conventional estimation methods, the variant of fluctuation analysis that considers finite sample moments only is able to identify both forms of self-affinity. When log returns are self-affine and long-range dependent under the alternative hypothesis, however, rescaled range analysis has higher power than fluctuation analysis. The techniques are illustrated by means of an analysis of the daily log returns for the indices of 11 stock markets of developed countries. Several of the smaller stock markets by capitalization exhibit evidence of long-range dependence in log returns. © 2012 Elsevier Inc. All rights reserved.

Intermittent self-pulsing in a fiber raman laser

We report on an experimental study of intermittent self-pulsing caused by the coupling of the first and second Stokes cascades in a fiber Raman laser © 2012 OSA.

Self-organization in social tagging systems

Individuals often imitate each other to fall into the typical group, leading to a self-organized state of typical behaviors in a community. In this paper, we model self-organization in social tagging systems and illustrate the underlying interaction and dynamics. Specifically, we introduce a model in which individuals adjust their own tagging tendency to imitate the average tagging tendency. We found that when users are of low confidence, they tend to imitate others and lead to a self-organized state with active tagging. On the other hand, when users are of high confidence and are stubborn to change, tagging becomes inactive. We observe a phase transition at a critical level of user confidence when the system changes from one regime to the other. The distributions of post length obtained from the model are compared to real data, which show good agreement. © 2011 American Physical Society.

Parental self-efficacy in managing food allergy and mental health predicts food allergy related quality of life

BACKGROUND: Food allergy has been shown to have a significant impact on quality of life (QoL) and can be difficult to manage in order to avoid potentially life threatening reactions. Parental self-efficacy (confidence) in managing food allergy for their child might explain variations in QoL. This study aimed to examine whether self-efficacy in parents of food allergic children was a good predictor of QoL of the family. METHODS: Parents of children with clinically diagnosed food allergy completed the Food Allergy Self-Efficacy Scale for Parents (FASE-P), the Food Allergy Quality of Life Parental Burden Scale (FAQL-PB), the GHQ-12 (to measure mental health) and the Food Allergy Independent Measure (FAIM), which measures perceived likelihood of a severe allergic reaction. RESULTS: A total of 434 parents took part. Greater parental QoL was significantly related to greater self-efficacy for food allergy management, better mental health, lower perceived likelihood of a severe reaction, older age in parent and child and fewer number of allergies (all p<0.05). Food allergy self-efficacy explained more of the variance in QoL than any other variable and self-efficacy related to management of social activities and precaution and prevention of an allergic reaction appeared to be the most important aspects. CONCLUSIONS: Parental self-efficacy in management of a child's food allergy is important and is associated with better parental QoL. It would be useful to measure self-efficacy at visits to allergy clinic in order to focus support; interventions to improve self-efficacy in parents of food allergic children should be explored. This article is protected by copyright. All rights reserved.

Sibling relations in preadolescence and adolescence: Compensatory and buffering effects

The current study is an examination of how support from siblings relates to psychological and academic well-being in preadolescence and adolescence in general, and the buffering and compensatory effects of sibling support in particular. Participants for the study were 694 African-American, European-American, and Hispanic-American students in grades 6 and 8. Participants were interviewed in school regarding their social support, ecological risk, and psychological well-being. Academic well-being was assessed using teacher reports and school records. Hierarchical regression analyses indicated that greater brother support was associated with more positive school attitudes and with higher overall self-esteem. In addition, sister support moderated the relationship between ecological risk and school adaptation. In terms of a compensatory effect, students under low mother support conditions receiving greater support from brothers, and students under low friend support conditions receiving greater support from brothers exhibited higher school achievement. The potential benefits of sibling support warrant a closer examination of the wide ranging issues involved in sibling relations. ^