140 research outputs found

    A Hierarchical Bayesian Approach to Ecological Count Data: A Flexible Tool for Ecologists

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    Many ecological studies use the analysis of count data to arrive at biologically meaningful inferences. Here, we introduce a hierarchical Bayesian approach to count data. This approach has the advantage over traditional approaches in that it directly estimates the parameters of interest at both the individual-level and population-level, appropriately models uncertainty, and allows for comparisons among models, including those that exceed the complexity of many traditional approaches, such as ANOVA or non-parametric analogs. As an example, we apply this method to oviposition preference data for butterflies in the genus Lycaeides. Using this method, we estimate the parameters that describe preference for each population, compare the preference hierarchies among populations, and explore various models that group populations that share the same preference hierarchy

    Recent Hybrids Recapitulate Ancient Hybrid Outcomes

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    Genomic outcomes of hybridization depend on selection and recombination in hybrids. Whether these processes have similar effects on hybrid genome composition in contemporary hybrid zones versus ancient hybrid lineages is unknown. Here we show that patterns of introgression in a contemporary hybrid zone in Lycaeides butterflies predict patterns of ancestry in geographically adjacent, older hybrid populations. We find a particularly striking lack of ancestry from one of the hybridizing taxa, Lycaeides melissa, on the Z chromosome in both the old and contemporary hybrids. The same pattern of reduced L. melissa ancestry on the Z chromosome is seen in two other ancient hybrid lineages. More generally, we find that patterns of ancestry in old or ancient hybrids are remarkably predictable from contemporary hybrids, which suggests selection and recombination affect hybrid genomes in a similar way across disparate time scales and during distinct stages of speciation and species breakdown

    Geographically multifarious phenotypic divergence during speciation

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    Abstract Speciation is an important evolutionary process that occurs when barriers to gene flow evolve between previously panmictic populations. Although individual barriers to gene flow have been studied extensively, we know relatively little regarding the number of barriers that isolate species or whether these barriers are polymorphic within species. Herein, we use a series of field and lab experiments to quantify phenotypic divergence and identify possible barriers to gene flow between the butterfly species Lycaeides idas and Lycaeides melissa. We found evidence that L. idas and L. melissa have diverged along multiple phenotypic axes. Specifically, we identified major phenotypic differences in female oviposition preference and diapause initiation, and more moderate divergence in mate preference. Multiple phenotypic differences might operate as barriers to gene flow, as shown by correlations between genetic distance and phenotypic divergence and patterns of phenotypic variation in admixed Lycaeides populations. Although some of these traits differed primarily between species (e.g., diapause initiation), several traits also varied among conspecific populations (e.g., male mate preference and oviposition preference)

    Caterpillars on a Phytochemical Landscape: The Case of Alfalfa and the Melissa Blue Butterfly

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    Modern metabolomic approaches that generate more comprehensive phytochemical profiles than were previously available are providing new opportunities for understanding plant‐animal interactions. Specifically, we can characterize the phytochemical landscape by asking how a larger number of individual compounds affect herbivores and how compounds covary among plants. Here we use the recent colonization of alfalfa (Medicago sativa) by the Melissa blue butterfly (Lycaeides melissa) to investigate the effects of indivdiual compounds and suites of covarying phytochemicals on caterpillar performance. We find that survival, development time, and adult weight are all associated with variation in nutrition and toxicity, including biomolecules associated with plant cell function as well as putative anti‐herbivore action. The plant‐insect interface is complex, with clusters of covarying compounds in many cases encompassing divergent effects on different aspects of caterpillar performance. Individual compounds with the strongest associations are largely specialized metabolites, including alkaloids, phenolic glycosides, and saponins. The saponins are represented in our data by more than 25 individual compounds with beneficial and detrimental effects on L. melissa caterpillars, which highlights the value of metabolomic data as opposed to approaches that rely on total concentrations within broad defensive classes

    Rationale, design and methods of the Study of Work and Pain (SWAP): a cluster randomised controlled trial testing the addition of a vocational advice service to best current primary care for patients with musculoskeletal pain (ISRCTN 52269669)

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    Background Musculoskeletal pain is a major contributor to short and long term work absence. Patients seek care from their general practitioner (GP) and yet GPs often feel ill-equipped to deal with work issues. Providing a vocational case management service in primary care, to support patients with musculoskeletal problems to remain at or return to work, is one potential solution but requires robust evaluation to test clinical and cost-effectiveness. Methods/Design This protocol describes a cluster randomised controlled trial, with linked qualitative interviews, to investigate the effect of introducing a vocational advice service into general practice, to provide a structured approach to managing work related issues in primary care patients with musculoskeletal pain who are absent from work or struggling to remain in work. General practices (n = 6) will be randomised to offer best current care or best current care plus a vocational advice service. Adults of working age who are absent from or struggling to remain in work due to a musculoskeletal pain problem will be invited to participate and 330 participants will be recruited. Data collection will be through patient completed questionnaires at baseline, 4 and 12 months. The primary outcome is self-reported work absence at 4 months. Incremental cost-utility analysis will be undertaken to calculate the cost per additional QALY gained and incremental net benefits. A linked interview study will explore the experiences of the vocational advice service from the perspectives of GPs, nurse practitioners (NPs), patients and vocational advisors. Discussion This paper presents the rationale, design, and methods of the Study of Work And Pain (SWAP) trial. The results of this trial will provide evidence to inform primary care practice and guide the development of services to provide support for musculoskeletal pain patients with work-related issues. Trial registration Current Controlled Trials ISRCTN52269669

    Ovarian cancer symptom awareness and anticipated delayed presentation in a population sample

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    Background: While ovarian cancer is recognised as having identifiable early symptoms, understanding of the key determinants of symptom awareness and early presentation is limited. A population-based survey of ovarian cancer awareness and anticipated delayed presentation with symptoms was conducted as part of the International Cancer Benchmarking Partnership (ICBP). Methods: Women aged over 50 years were recruited using random probability sampling (n = 1043). Computer-assisted telephone interviews were used to administer measures including ovarian cancer symptom recognition, anticipated time to presentation with ovarian symptoms, health beliefs (perceived risk, perceived benefits/barriers to early presentation, confidence in symptom detection, ovarian cancer worry), and demographic variables. Logistic regression analysis was used to identify the contribution of independent variables to anticipated presentation (categorised as < 3 weeks or ≥ 3 weeks). Results: The most well-recognised symptoms of ovarian cancer were post-menopausal bleeding (87.4%), and persistent pelvic (79.0%) and abdominal (85.0%) pain. Symptoms associated with eating difficulties and changes in bladder/bowel habits were recognised by less than half the sample. Lower symptom awareness was significantly associated with older age (p ≤ 0.001), being single (p ≤ 0.001), lower education (p ≤ 0.01), and lack of personal experience of ovarian cancer (p ≤ 0.01). The odds of anticipating a delay in time to presentation of ≥ 3 weeks were significantly increased in women educated to degree level (OR = 2.64, 95% CI 1.61 – 4.33, p ≤ 0.001), women who reported more practical barriers (OR = 1.60, 95% CI 1.34 – 1.91, p ≤ 0.001) and more emotional barriers (OR = 1.21, 95% CI 1.06 – 1.40, p ≤ 0.01), and those less confident in symptom detection (OR = 0.56, 95% CI 0.42 – 0.73, p ≤ 0.001), but not in those who reported lower symptom awareness (OR = 0.99, 95% CI 0.91 – 1.07, p = 0.74). Conclusions: Many symptoms of ovarian cancer are not well-recognised by women in the general population. Evidence-based interventions are needed not only to improve public awareness but also to overcome the barriers to recognising and acting on ovarian symptoms, if delays in presentation are to be minimised

    Group cognitive behavioural therapy for women with depression: pilot and feasibility study for a randomised controlled trial using mixed methods

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    <p>Abstract</p> <p>Background</p> <p>Group Cognitive Behavioural Therapy (CBT) may provide a means of improving mental health among people with depression but few studies have explored its effectiveness. Our aim was to examine the feasibility and acceptability of a randomised controlled trial of a group intervention based on CBT principles for women with depression in primary care.</p> <p>Methods</p> <p>Women aged 30 to 55 years were recruited and randomly assigned to either 12 weeks of the group intervention or usual care (control). The group intervention was based on a manual and used CBT and problem solving principles with weekly topics including raising activity levels, spotting and catching negative thoughts, problem solving and relaxation. Women were recruited from deprived areas of Bristol. The groups were run by facilitators with some experience and background in group work and one weeks training in use of the course manual. Assessments of mental health were made using measures including the PHQ-9. Follow-up was at 3 and 6 months after the intervention. Qualitative methods were used to support the design of the intervention and to help understand issues of acceptability and feasibility. Interviews were conducted with all participants at baseline and at 3 and 6 months although detailed qualitative analysis was based on a purposive sample of 20 participants at the 3 time points.</p> <p>Results</p> <p>Of the 86 participants assessed for eligibility, 52 were allocated to the intervention arm and 21 to the control group. The intervention was delivered according to the manual despite the limited training of the facilitators. The intervention was received favourably by participants and facilitators, with good attendance at sessions for those who engaged with the intervention. Follow up rates at 3 and 6 months for women in both the intervention and control arms were also good. The trial methodology used was appropriate and feasible.</p> <p>Conclusions</p> <p>This study showed that a randomised controlled trial of group CBT for women with depression is feasible and the intervention is acceptable, and may possibly prove to be effective in a larger trial. The cost effectiveness of group CBT for depression should be explored further in a full trial.</p> <p>Trial registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00663078">NCT00663078</a></p

    ‘Mind the gap’ - mapping services for young people with ADHD transitioning from child to adult mental health services

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    Background: Once considered to be a disorder restricted to childhood, Attention Deficit/Hyperactivity Disorder (ADHD) is now recognised to persist into adult life. However, service provision for adults with ADHD is limited. Additionally, there is little guidance or research on how best to transition young people with ADHD from child to adult services. Method: We report the findings of a survey of 96 healthcare professionals working in children’s (Child and Adolescent Mental Health Services and Community Paediatrics) and adult services across five NHS Trusts within the East Midlands region of England to gain a better understanding of the current provision of services for young people with ADHD transitioning into adult mental health services. Results: Our findings indicate a lack of structured guidelines on transitioning and little communication between child and adult services. Child and adult services had differing opinions on what they felt adult services should provide for ADHD cases. Adult services reported feeling ill-prepared to deal with ADHD patients, with clinicians in these services citing a lack of specific knowledge of ADHD and a paucity of resources to deal with such cases. Conclusions: We discuss suggestions for further research, including the need to map the national provision of services for adults with ADHD, and provide recommendations for commissioned adult ADHD services. We specifically advocate an increase in ADHD-specific training for clinicians in adult services, the development of specialist adult ADHD clinics and greater involvement of Primary Care to support the work of generic adult mental health services in adult ADHD management

    Study of user-experience of an objective test (QbTest) to aid ADHD assessment and medication management: a multi-methods approach

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    Background The diagnosis and monitoring of Attention deficit hyperactivity disorder (ADHD) typically relies on subjective reports and observations. Objective continuous performance tests (CPTs) have been incorporated into some services to support clinical decision making. However, the feasibility and acceptability of adding such a test into routine practice is unknown. The study aimed to investigate the feasibility and acceptability of adding an objective computerised test to the routine assessment and monitoring of attention deficit hyperactivity disorder (ADHD). Methods Semi-structured interviews were conducted with clinicians (n = 10) and families (parents/young people, n = 20) who participated in a randomised controlled trial. Additionally, the same clinicians (n = 10) and families (n = 76) completed a survey assessing their experience of the QbTest. The study took place in child and adolescent mental health and community paediatric clinics across the UK. Interview transcripts were thematically analysed. Results Interviewed clinicians and families valued the QbTest for providing an objective, valid assessment of symptoms. The QbTest was noted to facilitate communication between clinicians, families and schools. However, whereas clinicians were more unanimous on the usefulness of the QbTest, survey findings showed that, although the majority of families found the test useful, less than half felt the QbTest helped them understand the clinician’s decision making around diagnosis and medication. The QbTest was seen as a potentially valuable tool to use early in the assessment process to streamline the care pathway. Although clinicians were conscious of the additional costs, these could be offset by reductions in time to diagnosis and the delivery of the test by a Healthcare Assistant. Conclusions The findings indicate the QbTest is an acceptable and feasible tool to implement in routine clinical settings. Clinicians should be mindful to discuss the QbTest results with families to enable their understanding and engagement with the process. Further findings from definitive trials are required to understand the cost/benefit; however, the findings from this study support the feasibility and acceptability of integrating QbTest in the ADHD care pathway

    The effectiveness and cost-effectiveness of strength and balance Exergames to reduce falls risk for people aged 55 years and older in UK assisted living facilities: A multi-centre, cluster randomised controlled trial

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    Background: Falls are the leading cause of fatal and non-fatal unintentional injuries in older people. The use of Exergames (active, gamified video-based exercises) is a possible innovative, community-based approach. This study aimed to determine the effectiveness of a tailored OTAGO/FaME based strength and balance Exergame programme for improving balance, maintaining function and reducing falls risk in older people. Methods: A two-arm cluster randomised controlled trial recruiting adults aged 55 years and older living in 18 assisted-living (sheltered housing) facilities (clusters) in the UK. Standard care (physiotherapy advice and leaflet) was compared to a tailored 12-week strength and balance Exergame programme, supported by physiotherapists or trained assistants. Complete-case analysis (intention to treat) was used to compare Berg Balance Scale (BBS) at baseline and at 12 weeks. Secondary outcomes included: fear of falling, mobility, falls risk, pain, mood, fatigue, cognition, healthcare utilisation and health-related quality of life; self-reported physical activity and falls. Results: Eighteen clusters were randomised (9 to each arm) with 56 participants allocated to the intervention and 50 to the control (78% female, mean age 78 years). Fourteen participants withdrew over the 12 weeks (both arms), mainly for ill health. There was an adjusted mean improvement in balance (BBS) of 6.2 (95% CI 2.4 to 10.0), reduced fear of falling (p=0.007) and pain (p=0.02) in Exergame group. Mean attendance at sessions was 69% (mean exercising time of 33 minutes/week). 24% of control group and 20% of Exergame group fell over trial period. The change in falls rates significantly favoured the intervention (incident rate ratio 0.31 (95% CI 0.16 to 0.62, p=0.001)). The point estimate of the incremental cost effectiveness ratio (ICER) was £15,209.80 per QALY. Using 10,000 bootstrap replications, at the lower bound of the NICE threshold of £20,000 per QALY, there was a 61% probability of Exergames being cost-effective, rising to 73% at the upper bound of £30,000 per QALY. Conclusions: Exergames, as delivered in this trial, improve balance, pain and fear of falling and are a cost-effective fall prevention strategy in assisted living facilities for people aged 55 years or older
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