Suchergebnisse

AbstractSchools are an important setting for interventions to improve mental health. There is growing evidence that school climate – sometimes expressed as the perceptions that children have about the relationships, safety, values, and beliefs within their school – can impact child mental health. Poor child mental health is associated with feelings of distress as well deficits in functioning. However, while most studies have focused on school climate, climate at lower levels of nesting, including year group, may be important. Cross-sectional data on emotional and behavioural difficulties from 32,606 children in primary schools in Wales (ages 7–11, year groups 3–6) were collected via a school survey, delivered online and within the classroom environment to all children who consented, and analysed using multilevel modelling. Models were then extended to consider how aggregated measures of year group and school climate are associated with mental health outcomes. The unadjusted variance partition coefficients (VPCs) indicated that 2.8% of the variance in emotional difficulties and 3.2% in behavioural difficulties were attributable to differences in the year group, while school-level differences represented 2.4% and 3.5%, respectively. More positive year group and school climate were associated with more positive mental health outcomes. School and year group climate are independently associated with primary school children's mental health. Interventions to support mental health should aim to optimise the whole school climate, as well as climate within year group clusters.

BACKGROUND: Three arguments are usually invoked in favour of stepped wedge cluster randomised controlled trials: the logistic convenience of implementing an intervention in phases, the ethical benefit of providing the intervention to all clusters, and the potential to enhance the social acceptability of cluster randomised controlled trials. Are these alleged benefits real? We explored the logistic, ethical, and political dimensions of stepped wedge trials using case studies of six recent evaluations. METHODS: We identified completed or ongoing stepped wedge evaluations using two systematic reviews. We then purposively selected six with a focus on public health in high, middle, and low-income settings. We interviewed their authors about the logistic, ethical, and social issues faced by their teams. Two authors reviewed interview transcripts, identified emerging issues through qualitative thematic analysis, reflected upon them in the context of the literature, and invited all participants to co-author the manuscript. RESULTS: Our analysis raises three main points. First, the phased implementation of interventions can alleviate problems linked to simultaneous roll-out, but also brings new challenges. Issues to consider include the feasibility of organising intervention activities according to a randomised sequence, estimating time lags in implementation and effects, and accommodating policy changes during the trial period. Second, stepped wedge trials, like parallel cluster trials, require equipoise: without it, randomising participants to a control condition, even for a short time, remains problematic. In stepped wedge trials, equipoise is likely to lie in the degree of effect, effectiveness in a specific operational milieu, and the balance of benefit and harm, including the social value of better evaluation. Third, the strongest arguments for a stepped wedge design are logistic and political rather than ethical. The design is advantageous when simultaneous roll-out is impractical and when it increases the acceptability of using counterfactuals. CONCLUSIONS: The logistic convenience of phased implementation is context-dependent, and may be vitiated by the additional requirements of phasing. The potential for stepped wedge trials to enhance the social acceptability of cluster randomised trials is real, but their ethical legitimacy still rests on demonstrating equipoise and its configuration for each research question and setting.

Background: Three arguments are usually invoked in favour of stepped wedge cluster randomised controlled trials: the logistic convenience of implementing an intervention in phases, the ethical benefit of providing the intervention to all clusters, and the potential to enhance the social acceptability of cluster randomised controlled trials. Are these alleged benefits real? We explored the logistic, ethical, and political dimensions of stepped wedge trials using case studies of six recent evaluations. Methods: We identified completed or ongoing stepped wedge evaluations using two systematic reviews. We then purposively selected six with a focus on public health in high, middle, and low-income settings. We interviewed their authors about the logistic, ethical, and social issues faced by their teams. Two authors reviewed interview transcripts, identified emerging issues through qualitative thematic analysis, reflected upon them in the context of the literature, and invited all participants to co-author the manuscript. Results: Our analysis raises three main points. First, the phased implementation of interventions can alleviate problems linked to simultaneous roll-out, but also brings new challenges. Issues to consider include the feasibility of organising intervention activities according to a randomised sequence, estimating time lags in implementation and effects, and accommodating policy changes during the trial period. Second, stepped wedge trials, like parallel cluster trials, require equipoise: without it, randomising participants to a control condition, even for a short time, remains problematic. In stepped wedge trials, equipoise is likely to lie in the degree of effect, effectiveness in a specific operational milieu, and the balance of benefit and harm, including the social value of better evaluation. Third, the strongest arguments for a stepped wedge design are logistic and political rather than ethical. The design is advantageous when simultaneous roll-out is impractical and when it increases the acceptability of using counterfactuals. Conclusions: The logistic convenience of phased implementation is context-dependent, and may be vitiated by the additional requirements of phasing. The potential for stepped wedge trials to enhance the social acceptability of cluster randomised trials is real, but their ethical legitimacy still rests on demonstrating equipoise and its configuration for each research question and setting.

The evolutionary importance of hybridization and introgression has long been debated1. Hybrids are usually rare and unfit, but even infrequent hybridization can aid adaptation by transferring beneficial traits between species. Here we use genomic tools to investigate introgression in Heliconius, a rapidly radiating genus of neotropical butterflies widely used in studies of ecology, behaviour, mimicry and speciation2,3,4,5. We sequenced the genome of Heliconius melpomene and compared it with other taxa to investigate chromosomal evolution in Lepidoptera and gene flow among multiple Heliconius species and races. Among 12,669 predicted genes, biologically important expansions of families of chemosensory and Hox genes are particularly noteworthy. Chromosomal organization has remained broadly conserved since the Cretaceous period, when butterflies split from the Bombyx (silkmoth) lineage. Using genomic resequencing, we show hybrid exchange of genes between three co-mimics, Heliconius melpomene, Heliconius timareta and Heliconius elevatus, especially at two genomic regions that control mimicry pattern. We infer that closely related Heliconius species exchange protective colour-pattern genes promiscuously, implying that hybridization has an important role in adaptive radiation. ; We thank the governments of Colombia, Peru and Panama for permission to collect the butterflies. Sequencing was funded by contributions from consortium members. We thank M. Abanto for assistance in raising the inbred line. Individual laboratories were funded by the Leverhulme Trust (C.D.J.), the John Fell Fund and Christ Church College, Oxford (L. C. F.), The Royal Society (M.J., C.D.J.), the NSF (W.O.M., M. R. K., R. D. R., S. M., A. D. B.), the NIH (M. R. K., S. L. S., J.A.Y.), the CNRS (M.J.), the ERC (M.J., P. W. H. H.), the Banco de la Republica and COLCIENCAS (M. L.) and the BBSRC (J.M., C.D.J., M.L.B. and R.H.f.-C.). (Leverhulme Trust; John Fell Fund; Christ Church College, Oxford; Royal Society; NSF; NIH; CNRS; ERC; Banco de la ...