2,727 research outputs found

    Using the Medical Research Council framework for the development and evaluation of complex interventions in a theory-based infant feeding intervention to prevent childhood obesity:The baby milk intervention and trial

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    Introduction. We describe our experience of using the Medical Research Council framework on complex interventions to guide the development and evaluation of an intervention to prevent obesity by modifying infant feeding behaviours. Methods. We reviewed the epidemiological evidence on early life risk factors for obesity and interventions to prevent obesity in this age group. The review suggested prevention of excess weight gain in bottle-fed babies and appropriate weaning as intervention targets; hence we undertook systematic reviews to further our understanding of these behaviours. We chose theory and behaviour change techniques that demonstrated evidence of effectiveness in altering dietary behaviours. We subsequently developed intervention materials and evaluation tools and conducted qualitative studies with mothers (intervention recipients) and healthcare professionals (intervention deliverers) to refine them. We developed a questionnaire to assess maternal attitudes and feeding practices to understand the mechanism of any intervention effects. Conclusions. In addition to informing development of our specific intervention and evaluation materials, use of the Medical Research Council framework has helped to build a generalisable evidence base for early life nutritional interventions. However, the process is resource intensive and prolonged, and this should be taken into account by public health research funders. This trial is registered with ISRTCN: 20814693 Baby Milk Trial

    Planets in triple star systems--the case of HD188753

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    We consider the formation of the recently discovered ``hot Jupiter'' planet orbiting the primary component of the triple star system HD188753. Although the current outer orbit of the triple is too tight for a Jupiter-like planet to have formed and migrated to its current location, the binary may have been much wider in the past. We assume here that the planetary system formed in an open star cluster, the dynamical evolution of which subsequently led to changes in the system's orbital parameters and binary configuration. We calculate cross sections for various scenarios that could have led to the multiple system currently observed, and conclude that component A of HD188753 with its planet were most likely formed in isolation to be swapped in a triple star system by a dynamical encounter in an open star cluster. We estimate that within 500pc of the Sun there are about 1200 planetary systems which, like Hd188753, have orbital parameters unfavorable for forming planets but still having a planet, making it quite possible that the HD188753 system was indeed formed by a dynamical encounter in an open star cluster.Comment: ApJ Letters in pres

    Reliability and validity of a domain-specific last 7-d sedentary time questionnaire

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    Purpose: The objective of this study is to examine test-retest reliability, criterion validity, and absolute agreement of a self-report, last 7-d sedentary behavior questionnaire (SIT-Q-7d), which assesses total daily sedentary time as an aggregate of sitting/lying down in five domains (meals, transportation, occupation, nonoccupational screen time, and other sedentary time). Dutch (DQ) and English (EQ) versions of the questionnaire were examined. Methods: Fifty-one Flemish adults (ages 39.4 +/- 11.1 yr) wore a thigh accelerometer (activPAL3 (TM)) and simultaneously kept a domain log for 7 d. The DQ was subsequently completed twice (median test-retest interval: 3.3 wk). Thigh-acceleration sedentary time was log annotated to create comparable domain-specific and total sedentary time variables. Four hundred two English adults (ages 49.6 +/- 7.3 yr) wore a combined accelerometer and HR monitor (Actiheart (R)) for 6 d to objectively measure total sedentary time. The EQ was subsequently completed twice (median test-retest interval: 3.4 wk). In both samples, the questionnaire reference frame overlapped with the criterion measure administration period. All participants had five or more valid days of criterion data, including one or more weekend day. Results: Test-retest reliability (intraclass correlation coefficient (95% CI)) was fair to good for total sedentary time (DQ: 0.68 (0.50-0.81); EQ: 0.53 (0.44-0.62)) and poor to excellent for domain-specific sedentary time (DQ: from 0.36 (0.10-0.57) (meals) to 0.66 (0.46-0.79) (occupation); EQ: from 0.45 (0.35-0.54) (other sedentary time) to 0.76 (0.71-0.81) (meals)). For criterion validity (Spearman rho), significant correlations were found for total sedentary time (DQ: 0.52; EQ: 0.22; all P <0.001). Compared with domain-specific criterion variables (DQ), modest-to-strong correlations were found for domain-specific sedentary time (from 0.21 (meals) to 0.76 (P < 0.001) (screen time)). The questionnaire generally overestimated sedentary time compared with criterion measures. Conclusion: The SIT-Q-7d appears to be a useful tool for ranking individuals in large-scale observational studies examining total and domain-specific sitting

    The feasibility of rapid baseline objective physical activity measurement in a natural experimental study of a commuting population.

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    BACKGROUND: Studies of the effects of environmental interventions on physical activity should include valid measures of physical activity before and after the intervention. Baseline data collection can be difficult when the timetable for introduction of an intervention is outside researchers' control. This paper reports and reflects on the practical issues, challenges and results of rapid baseline objective physical activity measurement using accelerometers distributed by post in a natural experimental study. METHODS: A sample of working adults enrolling for the Commuting and Health in Cambridge study and expressing willingness to wear an activity monitor was selected to undertake baseline accelerometer assessment. Each selected participant received a study pack by post containing the core study questionnaire and an accelerometer to wear for seven consecutive days, and was asked to return their accelerometer and completed questionnaire in person or by post using the prepaid special delivery envelope provided. If a pack was not returned within two weeks of issue, a reminder was sent to the participant. Each participant received up to five reminders by various methods including letter, email, telephone and letter sent by recorded delivery. RESULTS: 95% of participants registering for the study were willing in principle to undertake accelerometer assessment. Using a pool of 221 accelerometers, we achieved a total of 714 issues of accelerometers to participants during a six month period. 116 (16%) participants declined to use the accelerometer after receiving it. Three accelerometers failed, 45 (6% of 714) were lost and many were returned with insufficient data recorded, resulted in 109 (15%) participants re-wearing their accelerometer for a second week of measurement. 550 (77%) participants completed data collection, 478 (87% of 550) to the required standard. A total of 694 reminders were issued to retrieve unreturned accelerometers. More than 90% of accelerometers were retrieved after a maximum of two reminders. CONCLUSIONS: It is feasible to use accelerometers to collect baseline objective physical activity data by post from a large number of participants in a limited time period. However, a substantial pool of devices is required and researchers need to be prepared to make significant efforts to recover some of the devices.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    'Keeping your body and mind active': an ethnographic study of aspirations for healthy ageing.

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    OBJECTIVE: To describe and explore perceptions, practices and motivations for active living in later life. DESIGN: Qualitative study with semistructured interviews and 'semistructured' participant observations of participant-selected activities, such as exercise classes, private or organised walks, shopping and gardening. PARTICIPANTS: 27 participants (65-80 years) from the European Prospective Investigation into Cancer Norfolk study, purposefully selected by gender, age, occupational class, living status and residential location; 19 of the participants agreed to be accompanied for observed activities. SETTING: Participants' homes, neighbourhoods, places of leisure activities and workplaces in Norfolk, England. RESULTS: All participants regarded a positive attitude as important for healthy ageing; this included staying active, both physically and mentally through sedentary activities such as reading and crosswords. 'Getting out of the house', being busy, or following a variety of interests were regarded as both important motivators and descriptions of their 'activeness'. Purposeful activities formed an important part of this, for example, still being engaged in paid or voluntary work, having caring responsibilities, or smaller incidental activities such as helping neighbours or walking for transport. Many also reported adapting previous, often lifelong, activity preferences and habits to their ageing body, or replacing them altogether with lower impact activities such as walking. This included adapting to the physical limitations of partners and friends which dictated the intensity and frequency of shared activities. The social context of activities could thus form a barrier to active living, but could also encourage it through companionship, social responsibilities and social pressures. CONCLUSIONS: Promoting and maintaining physical activity among older people may require more attention to activeness as an attitude and way of life as well as to its social context, and initiatives encouraging broader activity habits rather than discrete activities.This work was supported by the UK Research Councils’ Lifelong Health and Wellbeing (LLHW) Initiative in partnership with the Department of Health [grant number MR/K025147/1]; LLHW is led by the Medical Research Council. The work was undertaken under the auspices of the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence which is funded by the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust. SG and DO are also supported by the Medical Research Council [Unit programme numbers MC_UU_12015/4 and MC_UU_12015/6].This is the final version of the article. It was first available from BMJ via http://dx.doi.org/10.1136/bmjopen-2015-00997

    Disentangling telluric lines in stellar spectra

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    The use of a method of spectra disentangling for telluric lines is explained in detail, with a particular emphasis on high-precision radial-velocity measurements for the search for extrasolar planets. New improvements to the method are introduced.Comment: Accepted for publication in Astronomy and Astrophysic

    A Pilot Study of Value of Information Analysis to Support Research Recommendations for the National Institute for Health and Clinical Excellence

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    Background - This project developed as a result of the activities of the Research Teams at the Centre for Health Economics, University of York, and ScHARR at the University of Sheffield in the methods and application of decision analysis and value of information analysis as a means of informing the research recommendations made by NICE, as part of its Guidance to the NHS in England and Wales, and informing the deliberations of the NICE Research and Development Committee. Objectives - The specific objectives of the pilot study were to: • Demonstrate the benefits of using appropriate decision analytic methods and value of information analysis to inform research recommendations. • Establish the feasibility and resource implications of applying these methods in a timely way, to inform NICE. • Identify critical issues and methodological challenges to the use of value of information methods for research recommendations (with particular regard to the new reference case as a suitable basis for this type of analysis).

    An epidemic model for an evolving pathogen with strain-dependent immunity

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    Between pandemics, the influenza virus exhibits periods of incremental evolution via a process known as antigenic drift. This process gives rise to a sequence of strains of the pathogen that are continuously replaced by newer strains, preventing a build up of immunity in the host population. In this paper, a parsimonious epidemic model is defined that attempts to capture the dynamics of evolving strains within a host population. The ‘evolving strains’ epidemic model has many properties that lie in-between the Susceptible–Infected–Susceptible and the Susceptible–Infected–Removed epidemic models, due to the fact that individuals can only be infected by each strain once, but remain susceptible to reinfection by newly emerged strains. Coupling results are used to identify key properties, such as the time to extinction. A range of reproduction numbers are explored to characterise the model, including a novel quasi-stationary reproduction number that can be used to describe the re-emergence of the pathogen into a population with ‘average’ levels of strain immunity, analogous to the beginning of the winter peak in influenza. Finally the quasi-stationary distribution of the evolving strains model is explored via simulation
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