13,682 research outputs found
Cohort profile: the DASH (determinants of adolescent social well-being and health) study, an ethnically diverse cohort
No abstract available
Evaluation of moire techniques for wind tunnel metrology
The development of a moire technique suitable for the analysis of object deflections in a cryogenically cooled, transonic wind tunnel is described. The operating environment for the wind tunnel has a temperature range of 77 to 3390 k, pressure to 91390 Kgs/sq m, and noise to 150 dB SPL. Efforts were made to accomplish the following: to demonstrate projection moire as it would be used to study structural deflections; to use optical processing to multiply the sensitivity of the moire; and to investigate a system design based on the requirements of the wind tunnel geometry
Constraining viewing geometries of pulsars with single-peaked gamma-ray profiles using a multiwavelength approach
Since the launch of the Large Area Telescope (LAT) on board the Fermi
spacecraft in June 2008, the number of observed gamma-ray pulsars has increased
dramatically. A large number of these are also observed at radio frequencies.
Constraints on the viewing geometries of 5 of 6 gamma-ray pulsars exhibiting
single-peaked gamma-ray profiles were derived using high-quality radio
polarization data (Weltevrede et al., 2010). We obtain independent constraints
on the viewing geometries of 6 by using a geometric emission code to model the
Fermi LAT and radio light curves (LCs). We find fits for the magnetic
inclination and observer angles by searching the solution space by eye. Our
results are generally consistent with those previously obtained (Weltevrede et
al., 2010), although we do find small differences in some cases. We will
indicate how the gamma-ray and radio pulse shapes as well as their relative
phase lags lead to constraints in the solution space. Values for the flux
correction factor corresponding to the fits are also derived (with errors).Comment: 6 pages, 2 figures, 1 table, Proceedings of SAIP2011, the 56th Annual
Conference of the South African Institute of Physics (ISBN:
978-1-86888-688-3), ed. I. Basson and A. E. Botha, http://www.saip.org.za,
pp. 531-53
Self-consistent models for Coulomb heated X-ray pulsar atmospheres
Calculations of accreting magnetized neutron star atmospheres heated by the gradual deceleration of protons via Coulomb collisions are presented. Self consistent determinations of the temperature and density structure for different accretion rates are made by assuming hydrostatic equilibrium and energy balance, coupled with radiative transfer. The full radiative transfer in two polarizations, using magnetic cross sections but with cyclotron resonance effects treated approximately, is carried out in the inhomogeneous atmospheres
Strategies to improve retention in randomised trials: a Cochrane systematic review and meta-analysis
Objective: To quantify the effect of strategies to improve retention in randomised trials.<p></p>
Design: Systematic review and meta-analysis.<p></p>
Data sources Sources searched: MEDLINE, EMBASE, PsycINFO, DARE, CENTRAL, CINAHL, C2-SPECTR, ERIC, PreMEDLINE, Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings and a survey of all UK clinical trial research units.<p></p>
Review: methods Included trials were randomised evaluations of strategies to improve retention embedded within host randomised trials. The primary outcome was retention of trial participants. Data from trials were pooled using the fixed-effect model. Subgroup analyses were used to explore the heterogeneity and to determine whether there were any differences in effect by the type of strategy.<p></p>
Results: 38 retention trials were identified. Six broad types of strategies were evaluated. Strategies that increased postal questionnaire responses were: adding, that is, giving a monetary incentive (RR 1.18; 95% CI 1.09 to 1.28) and higher valued incentives (RR 1.12; 95% CI 1.04 to 1.22). Offering a monetary incentive, that is, an incentive given on receipt of a completed questionnaire, also increased electronic questionnaire response (RR 1.25; 95% CI 1.14 to 1.38). The evidence for shorter questionnaires (RR 1.04; 95% CI 1.00 to 1.08) and questionnaires relevant to the disease/condition (RR 1.07; 95% CI 1.01 to 1.14) is less clear. On the basis of the results of single trials, the following strategies appeared effective at increasing questionnaire response: recorded delivery of questionnaires (RR 2.08; 95% CI 1.11 to 3.87); a ‘package’ of postal communication strategies (RR 1.43; 95% CI 1.22 to 1.67) and an open trial design (RR 1.37; 95% CI 1.16 to 1.63). There is no good evidence that the following strategies impact on trial response/retention: adding a non-monetary incentive (RR=1.00; 95% CI 0.98 to 1.02); offering a non-monetary incentive (RR=0.99; 95% CI 0.95 to 1.03); ‘enhanced’ letters (RR=1.01; 95% CI 0.97 to 1.05); monetary incentives compared with offering prize draw entry (RR=1.04; 95% CI 0.91 to 1.19); priority postal delivery (RR=1.02; 95% CI 0.95 to 1.09); behavioural motivational strategies (RR=1.08; 95% CI 0.93 to 1.24); additional reminders to participants (RR=1.03; 95% CI 0.99 to 1.06) and questionnaire question order (RR=1.00, 0.97 to 1.02). Also based on single trials, these strategies do not appear effective: a telephone survey compared with a monetary incentive plus questionnaire (RR=1.08; 95% CI 0.94 to 1.24); offering a charity donation (RR=1.02, 95% CI 0.78 to 1.32); sending sites reminders (RR=0.96; 95% CI 0.83 to 1.11); sending questionnaires early (RR=1.10; 95% CI 0.96 to 1.26); longer and clearer questionnaires (RR=1.01, 0.95 to 1.07) and participant case management by trial assistants (RR=1.00; 95% CI 0.97 to 1.04).<p></p>
Conclusions: Most of the trials evaluated questionnaire response rather than ways to improve participants return to site for follow-up. Monetary incentives and offers of monetary incentives increase postal and electronic questionnaire response. Some strategies need further evaluation. Application of these results would depend on trial context and follow-up procedures.<p></p>
Key dating features for timber-framed dwellings in Surrey
This article is made available through the Brunel Open Access Publishing Fund. Copyright @ The Vernacular Architecture Group 2013. MORE OpenChoice articles are open access and distributed under the terms of the Creative Commons Attribution License 3.0.The main component of the Surrey Dendrochronology Project is the accurate dating of 177 ‘dwellings’, nearly all by tree-ring analysis. The dates are used to establish date ranges for 52 ‘key features’, which cover many aspects of timber-framing from building type to details of carpentry. It is shown that changes of method and fashion were in many cases surprisingly rapid, almost abrupt in historical terms. Previous dating criteria for timber-framed dwellings in the county have been refined and new criteria introduced. Clusters of change from the 1440s and the 1540s are shown and some possible historical links suggested.The Heritage Lottery Fund, the Domestic Buildings Research Group (Surrey), the Surrey Archaeological Society and the historical societies of Charlwood, Farnham and Nutfield
Conservation status of New Zealand freshwater invertebrates, 2013
The conservation status of 644 freshwater invertebrate taxa, across five Phyla, 28 Orders and 75 Families, was assessed using the New Zealand Threat Classification System (NZTCS) criteria. Forty-six species were ranked Nationally Critical, 11 Nationally Endangered and 16 Nationally Vulnerable. One hundred and seventy-two taxa were listed as Data Deficient. A full list is presented, along with summaries and brief notes on the most important changes. This list replaces all previous NZTCS lists for freshwater invertebrates
Perceived parenting and psychological well-being in UK ethnic minority adolescents
Background: Warm, caring parenting with appropriate supervision and control is considered to contribute to the best mental health outcomes for young people. The extent to which this view on ‘optimal’ parenting and health applies across ethnicities, warrants further attention. We examined associations between perceived parental care and parental control and psychological well-being among ethnically diverse UK adolescents.<p></p>
Methods: In 2003 a sample of 4349 pupils aged 11–13 years completed eight self-reported parenting items. These items were used to derive the parental care and control scores. Higher score represents greater care and control, respectively. Psychological well-being was based on total psychological difficulties score from Goodman's Strengths and Difficulties Questionnaire, increasing score corresponding to increasing difficulties.<p></p>
Results: All minority pupils had lower mean care and higher mean control scores compared with Whites. In models stratified by ethnicity, increasing parental care was associated with lower psychological difficulties score (better mental health) and increasing parental control with higher psychological difficulties score within each ethnic group, compared with reference categories. The difference in psychological difficulties between the highest and lowest tertiles of parental care, adjusted for age, sex, family type and socio-economic circumstances, was: White UK =−2.92 (95% confidence interval −3.72, −2.12); Black Caribbean =−2.08 (−2.94, −1.22); Nigerian/Ghanaian =−2.60 (−3.58, −1.62); Other African =−3.12 (−4.24, −2.01); Indian =−2.77 (−4.09, −1.45); Pakistani/ Bangladeshi =−3.15 (−4.27, −2.03). Between ethnic groups (i.e. in models including ethnicity), relatively better mental health of minority groups compared with Whites was apparent even in categories of low care and low autonomy. Adjusting for parenting scores, however, did not fully account for the protective effect of minority ethnicity.<p></p>
Conclusions: Perceived quality of parenting is a correlate of psychological difficulties score for all ethnic groups despite differences in reporting. It is therefore likely that programmes supporting parenting will be effective regardless of ethnicity.<p></p>
High Energy Neutrinos and Photons from Curvature Pions in Magnetars
We discuss the relevance of the curvature radiation of pions in strongly
magnetized pulsars or magnetars, and their implications for the production of
TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as
high energy photons.Comment: 19 pages, 4 figures, to appear in JCA
- …