3,595 research outputs found

    Pulsed radiolysis of model aromatic polymers and epoxy based matrix materials

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    Models of primary processes leading to deactivation of energy deposited by a pulse of high energy electrons were derived for epoxy matrix materials and polyl-vinyl naphthalene. The basic conclusion is that recombination of initially formed charged states is complete within 1 nanosecond, and subsequent degradation chemistry is controlled by the reactivity of these excited states. Excited states in both systems form complexes with ground state molecules. These excimers or exciplexes have their characteristics emissive and absorptive properties and may decay to form separated pairs of ground state molecules, cross over to the triplet manifold or emit fluorescence. ESR studies and chemical analyses subsequent to pulse radiolysis were performed in order to estimate bond cleavage probabilities and net reaction rates. The energy deactivation models which were proposed to interpret these data have led to the development of radiation stabilization criteria for these systems

    Challenges of systematic reviewing integrative health care.

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    This article is based on an extensive review of integrative medicine (IM) and integrative health care (IHC). Since there is no general agreement of what constitutes IM/IHC, several major problems were identified that make the review of work in this field problematic. In applying the systematic review methodology, we found that many of those captured articles that used the term integrative medicine were in actuality referring to adjunctive, complementary, or supplemental medicine. The objective of this study was to apply a sensitivity analysis to demonstrate how the results of a systematic review of IM and IHC will differ according to what inclusion criteria is used based on the definition of IM/IHC. By analyzing 4 different scenarios, the authors show that, due to unclear usage of these terms, results vary dramatically, exposing an inconsistent literature base for this field

    The effects of energetic proton bombardment on polymeric materials: Experimental studies and degradation models

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    This report describes 3 MeV proton bombardment experiments on several polymeric materials of interest to NASA carried out on the Tandem Van De Graff Accelerator at the California Institute of Technology's Kellogg Radiation Laboratory. Model aromatic and aliphatic polymers such as poly(1-vinyl naphthalene) and poly(methyl methacrylate), as well as polymers for near term space applications such as Kapton, Epoxy and Polysulfone, have been included in this study. Chemical and physical characterization of the damage products have been carried out in order to develop a model of the interaction of these polymers with the incident proton beam. The proton bombardment methodology developed at the Jet Propulsion Laboratory and reported here is part of an ongoing study on the effects of space radiation on polymeric materials. The report is intended to provide an overview of the mechanistic, as well as the technical and experimental, issues involved in such work rather than to serve as an exhaustive description of all the results

    The United States Chiropractic Workforce: An alternative or complement to primary care?

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    UnlabelledBackgroundIn the United States (US) a shortage of primary care physicians has become evident. Other health care providers such as chiropractors might help address some of the nation's primary care needs simply by being located in areas of lesser primary care resources. Therefore, the purpose of this study was to examine the distribution of the chiropractic workforce across the country and compare it to that of primary care physicians.MethodsWe used nationally representative data to estimate the per 100,000 capita supply of chiropractors and primary care physicians according to the 306 predefined Hospital Referral Regions. Multiple variable Poisson regression was used to examine the influence of population characteristics on the supply of both practitioner-types.ResultsAccording to these data, there are 74,623 US chiropractors and the per capita supply of chiropractors varies more than 10-fold across the nation. Chiropractors practice in areas with greater supply of primary care physicians (Pearson's correlation 0.17, p-value < 0.001) and appear to be more responsive to market conditions (i.e. more heavily influenced by population characteristics) in regards to practice location than primary care physicians.ConclusionThese findings suggest that chiropractors practice in areas of greater primary care physician supply. Therefore chiropractors may be functioning in more complementary roles to primary care as opposed to an alternative point of access

    Associations between neighbourhood deprivation and engagement in arts, culture and heritage: evidence from two nationally-representative samples

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    Background: Previous research has shown the benefits of arts and cultural engagement for physical, mental and social wellbeing. This engagement is socially and geographically patterned. Yet it remains unclear whether place-based attributes are associated with engagement behaviour independent of individual factors. Therefore, the aim of this cross-sectional study was to robustly disentangle associations between geographical deprivation and arts engagement from the individual socio-demographic factors that tend to correlate with residential locations. Methods: Two different samples drawn from two representative surveys of adults living in England were compared – Understanding Society Wave 2 (2010/12) (N = 14,782) and Taking Part survey (2010/11) (N = 4575). Propensity score matching (PSM) was applied to investigate the association between neighbourhood deprivation (20% most deprived vs 20% least deprived) and arts engagement (arts participation, cultural attendance and museums and heritage engagement). Results: Higher levels of neighbourhood deprivation were associated with lower arts, culture and heritage engagement independent of individuals’ demographic backgrounds, socio-economic characteristics and regional locations. When exploring subcategories of deprivation, similar results were obtained across deprivation domains. Results were also consistent when using more distinct categories of deprivation (i.e. 10% most deprived vs 10% least deprived) and when comparing people living in the 20% most deprived neighbourhoods with those living in the 40% medium-deprived areas. Conclusion: This study is the first to apply a robust PSM technique to examine the association between neighbourhood deprivation and arts engagement using two nationally-representative samples. Results show that neighbourhood deprivation may act as a barrier that could prevent people from engaging in the arts, which in turn may exacerbate social and health inequalities. This highlights the importance of place-based schemes that focus on increasing individual motivation and capacity to engage in arts and cultural activities, especially in areas of high deprivation

    Associations between community cultural engagement and life satisfaction, mental distress and mental health functioning using data from the UK Household Longitudinal Study (UKHLS): are associations moderated by area deprivation?

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    OBJECTIVES: The association between community cultural engagement and mental health and well-being is well established. However, little is known about whether such associations are influenced by area characteristics. This study therefore examined whether the association between engagement in community cultural assets (attendance at cultural events, visiting museums and heritage sites) and subsequent well-being (life satisfaction, mental distress and mental health functioning) is moderated by neighbourhood deprivation. DESIGN: Data were drawn from Understanding Society: The UK Household Longitudinal Study waves 2 and 5. Participating households’ addresses were geocoded into statistical neighbourhood zones categorised according to their level of area deprivation. SETTING: General population. PARTICIPANTS: UK general adult population, with a total sample of 14 783. MAIN OUTCOME MEASURES: Life satisfaction was measured with a seven-point scale (1: completely unsatisfied to 7: completely satisfied). Mental distress was measured using the General Health Questionnaire 12. Mental health functioning was measured using 12-item Short Form Health Survey (SF-12). RESULTS: Using Ordinary Least Squares (OLS) regression, we found that engagement in cultural assets was consistently and positively associated with subsequent life satisfaction and mental health functioning and negatively associated with mental distress. Importantly, such associations were independent of individuals’ demographic background, socioeconomic characteristics and regional location. The results also show that relationships between engagement in community cultural assets and well-being were stronger in more deprived areas. CONCLUSIONS: This study shows that engagement in community cultural assets is associated with better well-being, with some evidence that individuals in areas of high deprivation potentially may benefit more from these engagements. Given that causal mechanisms were not tested, causal claims cannot be generated from the results. However, the results suggest that place-based funding schemes that involve investment in areas of higher deprivation to improve engagement rates should be explored further to see if they can help promote better well-being among residents

    Patterns of social inequality in arts and cultural participation: Findings from a nationally representative sample of adults living in the United Kingdom of Great Britain and Northern Ireland

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    CONTEXT: A significant amount of literature indicates the health benefits of arts engagement. However, as this engagement is socially patterned, differential access to and participation in the arts may contribute to social and health inequalities. OBJECTIVE: This study aimed to uncover the patterns of participation in arts activities and engagement with culture and heritage among adults in the United Kingdom of Great Britain and Northern Ireland, and to examine whether such patterns are associated with demographic and socioeconomic characteristics. METHODOLOGY: We applied latent class analysis to data on arts and cultural participation among 30 695 people in the Understanding Society study. Multinomial logistic regression was used to identify predictors for the patterns of activity engagement. RESULTS: For arts participation, adults were clustered into “engaged omnivores,” “visual and literary arts,” “performing arts” and “disengaged.” For cultural engagement, adults were clustered into “frequently engaged,” “infrequently engaged” and “rarely engaged.” Regression analysis showed that the patterns of arts activity were structured by demographic and socioeconomic factors. CONCLUSION: This study reveals a social gradient in arts and cultural engagement. Given the health benefits of arts engagement, this suggests the importance of promoting equal access to arts and cultural programmes, to ensure that unequal engagement does not exacerbate health inequalities
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