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Search Results: 1 - 10 of 298525 matches for " Mitch J. Duncan "
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Perceived environment and physical activity: a meta-analysis of selected environmental characteristics
Mitch J Duncan, John C Spence, W Kerry Mummery
International Journal of Behavioral Nutrition and Physical Activity , 2005, DOI: 10.1186/1479-5868-2-11
Abstract: Published studies were identified from electronic databases and searches of personal files. Studies were examined to determine the environmental constructs most frequently studied. Included studies (N = 16) examined at least one identified construct and determined associations between perceived environmental constructs and PA using logistic regression. Data were analyzed separately for crude and adjusted ORs using general-variance based fixed effect models.No significant associations emerged between environmental characteristics and PA using crude OR. The perceived presence of PA facilities (OR 1.20, 95% 1.06–1.34), sidewalks (OR 1.23, 95% 1.13–1.32), shops and services (OR 1.30, 95% 1.14–1.46) and perceiving traffic not to be a problem (OR 1.22, 95% 1.08–1.37) were positively associated with activity using adjusted ORs. Variance in PA accounted for by significant associations ranged from 4% (heavy traffic not a problem) to 7% (presence of shops and services).Results of the meta-analysis support the relevance of perceived environmental characteristics for understanding population PA. These results should encourage the use of comprehensive ecological models that incorporate variables beyond basic demographic information.The burden of disease attributable to physical inactivity is estimated at $377 million in Australia [1], $2.1 billion in Canada [2] and $24 billion in the U.S. [3], and continues to rise as large majorities of populations remain insufficiently active for health benefits. Research relating to the determinants of physical activity and inactivity has previously focused on determinants at the individual level, largely neglecting physical environments as influences of PA [4]. It is now acknowledged that environments that people build and inhabit provide potential opportunities and barriers to engaging in physically active lifestyles [5,6]. Furthermore, suburban sprawl and the way neighborhoods are designed are related to the physical health and bodyweight
Development and reliability testing of a self-report instrument to measure the office layout as a correlate of occupational sitting
Duncan Mitch J,Rashid Mahbub,Vandelanotte Corneel,Cutumisu Nicoleta
International Journal of Behavioral Nutrition and Physical Activity , 2013, DOI: 10.1186/1479-5868-10-16
Abstract: Background Spatial configurations of office environments assessed by Space Syntax methodologies are related to employee movement patterns. These methods require analysis of floors plans which are not readily available in large population-based studies or otherwise unavailable. Therefore a self-report instrument to assess spatial configurations of office environments using four scales was developed. Methods The scales are: local connectivity (16 items), overall connectivity (11 items), visibility of co-workers (10 items), and proximity of co-workers (5 items). A panel cohort (N = 1154) completed an online survey, only data from individuals employed in office-based occupations (n = 307) were used to assess scale measurement properties. To assess test-retest reliability a separate sample of 37 office-based workers completed the survey on two occasions 7.7 (±3.2) days apart. Redundant scale items were eliminated using factor analysis; Chronbach’s α was used to evaluate internal consistency and test re-test reliability (retest-ICC). ANOVA was employed to examine differences between office types (Private, Shared, Open) as a measure of construct validity. Generalized Linear Models were used to examine relationships between spatial configuration scales and the duration of and frequency of breaks in occupational sitting. Results The number of items on all scales were reduced, Chronbach’s α and ICCs indicated good scale internal consistency and test re-test reliability: local connectivity (5 items; α = 0.70; retest-ICC = 0.84), overall connectivity (6 items; α = 0.86; retest-ICC = 0.87), visibility of co-workers (4 items; α = 0.78; retest-ICC = 0.86), and proximity of co-workers (3 items; α = 0.85; retest-ICC = 0.70). Significant (p ≤ 0.001) differences, in theoretically expected directions, were observed for all scales between office types, except overall connectivity. Significant associations were observed between all scales and occupational sitting behaviour (p ≤ 0.05). Conclusion All scales have good measurement properties indicating the instrument may be a useful alternative to Space Syntax to examine environmental correlates of occupational sitting in population surveys.
Cross-Sectional Associations between Multiple Lifestyle Behaviors and Health-Related Quality of Life in the 10,000 Steps Cohort
Mitch J. Duncan, Christopher E. Kline, Corneel Vandelanotte, Charli Sargent, Naomi L. Rogers, Lee Di Milia
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0094184
Abstract: Background The independent and combined influence of smoking, alcohol consumption, physical activity, diet, sitting time, and sleep duration and quality on health status is not routinely examined. This study investigates the relationships between these lifestyle behaviors, independently and in combination, and health-related quality of life (HRQOL). Methods Adult members of the 10,000 Steps project (n = 159,699) were invited to participate in an online survey in November-December 2011. Participant socio-demographics, lifestyle behaviors, and HRQOL (poor self-rated health; frequent unhealthy days) were assessed by self-report. The combined influence of poor lifestyle behaviors were examined, independently and also as part of two lifestyle behavior indices, one excluding sleep quality (Index 1) and one including sleep quality (Index 2). Adjusted Cox proportional hazard models were used to examine relationships between lifestyle behaviors and HRQOL. Results A total of 10,478 participants provided complete data for the current study. For Index 1, the Prevalence Ratio (p value) of poor self-rated health was 1.54 (p = 0.001), 2.07 (p≤0.001), 3.00 (p≤0.001), 3.61 (p≤0.001) and 3.89 (p≤0.001) for people reporting two, three, four, five and six poor lifestyle behaviors, compared to people with 0–1 poor lifestyle behaviors. For Index 2, the Prevalence Ratio (p value) of poor self-rated health was 2.26 (p = 0.007), 3.29 (p≤0.001), 4.68 (p≤0.001), 6.48 (p≤0.001), 7.91 (p≤0.001) and 8.55 (p≤0.001) for people reporting two, three, four, five, six and seven poor lifestyle behaviors, compared to people with 0–1 poor lifestyle behaviors. Associations between the combined lifestyle behavior index and frequent unhealthy days were statistically significant and similar to those observed for poor self-rated health. Conclusions Engaging in a greater number of poor lifestyle behaviors was associated with a higher prevalence of poor HRQOL. This association was exacerbated when sleep quality was included in the index.
The Concept of Function in the Analysis of Behavior
Fryling, Mitch J.;Hayes, Linda J.;
Revista mexicana de análisis de la conducta , 2011, DOI: 10.5514/rmac.v37.i1.24686
Abstract: the concept of function is central to the discipline of behavior analysis; it serves to characterize the subject matter of the science and is also used to distinguish behavior analysis from other approaches in psychology. in this commentary we assess the concept of function as it is used within behavior analysis. this is done through the perspective of interbehaviorism, with attention to implications for the validity and significance of behavior analysis as a scientific system. problems are identified, and an alternative is proposed. finally, the implications of the adoption of this alternative are reviewed.
Very high efficiency photospheric emission in long duration gamma-ray bursts
Davide Lazzati,Brian J. Morsony,Mitch Begelman
Physics , 2009, DOI: 10.1088/0004-637X/700/1/L47
Abstract: We numerically analyze the evolution of a long-duration gamma-ray burst jet as it leaves the progenitor star and propagates to the photospheric radius, where radiation can be released. We find that the interaction of the relativistic material with the progenitor star has influences well beyond the stellar surface. Tangential collimation shocks are observed throughout the jet evolution, out to about 100 stellar radii, which is the whole range of our simulation. We find that the jet is internally hot at the photospheric radius and we compute the photospheric emission. The photosphere is a very efficient radiator, capable of converting more than half of the total energy of the jet into radiation. We show that bright photospheres are a common feature of jets born inside massive progenitor stars and that this effect can explain the high radiative efficiency observed in long-duration bursts.
Speaking to the experts and patients: Recommendations for improving ART adherence
J Frank, N Duncan
Health SA Gesondheid , 2009,
Abstract: This article reports on the fi ndings of a study that aimed to explore experts’ and patients’ opinions and recommendations regarding adherence to antiretroviral medication. This study was prompted firstly by the lack of existing local research on adherence to antiretroviral therapy (ART) and secondly by the importance of adherence, given the recent introduction of ART to the public health sector. Four experts and seven patients were interviewed. The experts had worked within the HIV/AIDS fi eld for at least two years while the patients (chosen from public antiretroviral roll-out programmes) had been on ART for at least six months. These interviews were transcribed and analysed using thematic content analysis. This article focuses specifi cally on the recommendations for improving adherence that emerged from the experts' and patients' interviews. While the experts and patients generated two fairly distinct sets of recommendations (clearly informed by their different experiences and knowledge), both groups emphasised the importance of the mediating effects of social support and the healthcare provider–patient relationship in adherence to ART medication Opsomming: Gesprekke met kundiges en pasi nte: Aanbevelings ter verbetering van ART-nakoming. Hierdie artikel doen verslag oor die bevindinge van ’n studie wat kundiges en pasi nte se menings en aanbevelings ten opsigte van die nakoming van antiretrovirale medikasievoorskrifte ondersoek het. Die studie is in die eerste plek uitgevoer na aanleiding van die gebrek aan bestaande plaaslike navorsing oor die nakoming van antiretrovirale terapie (ART) en in die tweede plek na aanleiding van die belangrikheid van nakoming in die lig van die onlangse bekendstelling van ART in die openbaregesondheidsektor. Onderhoude is met vier kundiges en sewe pasi nte gevoer. Die kundiges het vir ten minste twee jaar binne die MIV/Vigs-omgewing gewerk en die pasi nte (wat uit die openbare antiretrovirale bekendstellingsprogramme gekies is) het ten minste ses maande van ART-terapie ondergaan. Die onderhoude is getranskribeer en met die gebruik van tematiese inhoudsanalise ontleed. Hierdie artikel fokus spesifi ek op die aanbevelings vir die verbetering van nakoming wat uit die onderhoude met die kundiges en die pasi nte gespruit het. Terwyl die kundiges en die pasi nte twee redelik uiteenlopende stelle aanbevelings gemaak het (wat duidelik deur hulle onderskeie ondervinding en kennis be nvloed is), het altwee groepe beklemtoon dat die bemiddelende effek van maatskaplike ondersteuning en die verhouding tussen die pasi nt en die voorsiener van gesondheidsorg ’n belangrike rol speel in die nakoming van ART-medikasievoorskrifte.
Tablettes mathématiques de la collection Hilprecht
Duncan J. Melville
Aestimatio : Critical Reviews in the History of Science , 2009,
Abstract:
Tablettes mathématiques de Nippur. 1er partie: Reconstitution du cursus scolaire. 2me partie: édition des tablettes conservées au Mus e Archéologique d’Istanbul, avec la collaboration de Veysel Donbaz et de Asuman D nmez, translittération des textes lexicaux et littéraires par Antoine Cavigneaux by Christine Proust
Duncan J. Melville
Aestimatio : Critical Reviews in the History of Science , 2008,
Abstract:
Host–pathogen dynamics: it's complicated!
Margaret J. Duncan
Journal of Oral Microbiology , 2012, DOI: 10.3402/jom.v4i0.11482
Abstract:
Theoretical electron energy loss spectroscopy of isolated graphene
Duncan J. Mowbray
Physics , 2014, DOI: 10.1002/pssb.201451174
Abstract: A thorough understanding of the electronic structure is a necessary first step for the design of nanoelectronics, chemical/bio-sensors, electrocatalysts, and nanoplasmonics using graphene. As such, theoretical spectroscopic techniques to describe collective excitations of graphene are of fundamental importance. Starting from density functional theory (DFT), linear response time dependent DFT in frequency-reciprocal space within the random phase approximation (TDDFT-RPA) is used to describe the loss function -Im{1/{\epsilon}(q,{\omega})} for isolated graphene. To ensure any spurious interactions between layers are removed, both a radial cutoff of the Coulomb kernel, and extra vacuum directly at the TDDFT-RPA level are employed. A combination of both methods is found to provide a correct description of the electron energy loss spectra of isolated graphene, at a significant reduction in computational cost compared to standard methods.
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