392 research outputs found

    Thomas-Fermi Approximation for a Condensate with Higher-order Interactions

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    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

    N-body Efimov states of trapped bosons

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    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 Behaviour–Impact Gap Problem

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    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 “green” and “brown” consumers. No significant difference was found between the ecological footprints of the two groups—suggesting 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 (behaviour–impact gap) problem, which is an interesting addition to research in the field of environmental awareness gaps

    Living apart, losing sympathy? How neighbourhood context affects attitudes to redistribution and to welfare recipients

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    Rising levels of income inequality have been directly linked to rising levels of spatial segregation. In this paper, we explore whether rising segregation may in turn erode support for the redistributive policies of the welfare state, further increasing levels of inequality – a form of positive feedback. The role of the neighbourhood has been neglected in attitudes research but, building on both political geography and ‘neighbourhood effects’ literatures, we theorise that neighbourhood context may shape attitudes through the transmission of attitudes directly and through the accumulation of relevant knowledge. We test this through multilevel modelling of data from England on individual attitudes to redistribution in general and to welfare benefit recipients in particular. We show that the individual factors shaping these attitudes are quite different and that the influence of neighbourhood context also varies as a result. The findings support the idea that neighbourhood context shapes attitudes, with the knowledge accumulation mechanism likely to be the more important. Rising spatial segregation would appear to erode support for redistribution but to increase support for welfare recipients – at least in a context where the dominant media discourse presents such a stigmatising image of those on welfare benefits

    Perceptions of Group-Based Walks and Strategies to Inform the Development of an Intervention in Retirement Villages: Perspectives of Residents and Village Managers.

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    The aim of the present study was explore perceptions of group-based walking and gather suggestions to inform the development of a group-based walking intervention among older adults in retirement villages. Twenty-four physically inactive residents (16 female, 8 male; age range: 69-88) and 4 managers from four retirement villages were interviewed. Inductive thematic analysis revealed 6 broad themes: lack of motivation, values versus constraints, fears and confidence, need for structure, creating a sense of belonging, and the physical environment as a double-edged sword. Proposed intervention strategies included using trained walk leaders, using small groups, planning for flexibility, setting attainable goals, creating a routine, creating opportunities for sharing experiences, and planning a variety of walks. Group-based walking programs may be used to promote physical activity but careful planning of such programs is needed in order to make it appealing and feasible to a diverse group of residents

    "Step by Step". A feasibility study of a lunchtime walking intervention designed to increase walking, improve mental well-being and work performance in sedentary employees: Rationale and study design

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    BACKGROUND: Following an extensive recruitment campaign, a 16-week lunchtime intervention to increase walking was implemented with insufficiently physically active University employees to examine programme feasibility and the effects of the programme in increasing walking behaviour, and in improving well-being and work performance. METHODS/DESIGN: A feasibility study in which participants were randomised to an immediate treatment or a delayed treatment control (to start at 10 weeks) group. For the first ten weeks of the intervention, participants took part in three facilitator-led group walks per week each of thirty minutes duration and were challenged to accumulate another sixty minutes of walking during the weekends. In the second phase of the intervention, the organised group walks ceased to be offered and participants were encouraged to self-organise their walks. Motivational principles were employed using contemporary motivational theory. Outcome measures (including self-reported walking, step counts, cardiovascular fitness, general and work-related well-being and work performance) were assessed at baseline, at the end of the 16-week intervention and (for some) four months after the end of the intervention. Process and outcome assessments were also taken throughout, and following, the intervention. DISCUSSION: The results of the intervention will determine the feasibility of implementing a lunchtime walking programme to increase walking behaviour, well-being and performance in sedentary employees. If successful, there is scope to implement definitive trials across a range of worksites with the aim of improving both employee and organisational health

    Reconstruction of the metabolic network of Pseudomonas aeruginosa to interrogate virulence factor synthesis

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    Virulence-linked pathways in opportunistic pathogens are putative therapeutic targets that may be associated with less potential for resistance than targets in growth-essential pathways. However, efficacy of virulence-linked targets may be affected by the contribution of virulence-related genes to metabolism. We evaluate the complex interrelationships between growth and virulence-linked pathways using a genome-scale metabolic network reconstruction of Pseudomonas aeruginosa strain PA14 and an updated, expanded reconstruction of P. aeruginosa strain PAO1. The PA14 reconstruction accounts for the activity of 112 virulence-linked genes and virulence factor synthesis pathways that produce 17 unique compounds. We integrate eight published genome-scale mutant screens to validate gene essentiality predictions in rich media, contextualize intra-screen discrepancies and evaluate virulence-linked gene distribution across essentiality datasets. Computational screening further elucidates interconnectivity between inhibition of virulence factor synthesis and growth. Successful validation of selected gene perturbations using PA14 transposon mutants demonstrates the utility of model-driven screening of therapeutic targets

    Protocol for the Residents in Action pilot cluster-randomised controlled trial (RiAT): Evaluating a behaviour change intervention to promote walking, reduce sitting and improve mental health in physically inactive older adults in 9 retirement villages

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    Introduction: Ageing is accompanied by increased risks of chronic disease, declined functioning and increased dependency. Physical activity is critical to retaining health and independence, but the majority of older people are insufficiently physically active to achieve these benefits and have high levels of sedentary (sitting) time. Activity programmes are often offered in retirement villages; however, their uptake is limited. Furthermore, although the physical environment in and around these villages can play an important role in decisions to be physically active, its role is often overlooked by research in these settings. We aim to develop, implement and evaluate a proof-of- concept motivationally embellished intervention designed to increase walking, reduce sitting and improve mental health in residents in retirement villages. Methods and analysis: This will be a 16-week pilot intervention using a cluster randomised design with retirement villages as the unit of randomisation and residents as the unit of assessment. Fourteen retirement villages around Perth, Western Australia, will be recruited for the intervention. Objective audits of neighbourhood environments around each village will be completed using the Pathway Environmental Audit Tool. Seven villages will be randomised to the experimental arm and seven to the control arm. Only participants in the experimental arm will receive motivational training. All outcomes will be assessed at baseline, end of intervention and 6-month follow-up. Changes in physical activity levels, sitting time and mental health will be examined. Multilevel modelling will be used to analyse the data. A mixed methods process evaluation will also be conducted. Ethics and dissemination: Ethics approval was granted by Curtin University’s Human Research Ethics Committee (HREC2016-0187). The results of the study will be disseminated via peer-reviewed publications, conference presentations and reports to, and seminars with, stakeholders

    Making Sense of a New Transport System: An Ethnographic Study of the Cambridgeshire Guided Busway

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    An increase in public transport use has the potential to contribute to improving population health, and there is growing interest in innovative public transport systems. Yet how new public transport infrastructure is experienced and integrated (or not) into daily practice is little understood. We investigated how the Cambridgeshire Guided Busway, UK, was used and experienced in the weeks following its opening, using the method of participant observation (travelling on the busway and observing and talking to passengers) and drawing on Normalization Process Theory to interpret our data. Using excerpts of field notes to support our interpretations, we describe how the ease with which the new transport system could be integrated into existing daily routines was important in determining whether individuals would continue to use it. It emerged that there were two groups of passengers with different experiences and attitudes. Passengers who had previously travelled frequently on regular bus services did not perceive the new system to be an improvement; consequently, they were frustrated that it was differentiated from and not coherent with the regular system. In contrast, passengers who had previously travelled almost exclusively by car appraised the busway positively and perceived it to be a novel and superior form of travel. Our rich qualitative account highlights the varied and creative ways in which people learn to use new public transport and integrate it into their everyday lives. This has consequences for the introduction and promotion of future transport innovations. It is important to emphasise the novelty of new public transport, but also the ways in which its use can become ordinary and routine. Addressing these issues could help to promote uptake of other public transport interventions, which may contribute to increasing physical activity and improving population health. Š 2013 Jones et al
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