834 research outputs found

    Sequence validation of candidates for selectively important genes in sunflower

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    Analyses aimed at identifying genes that have been targeted by past selection provide a powerful means for investigating the molecular basis of adaptive differentiation. In the case of crop plants, such studies have the potential to not only shed light on important evolutionary processes, but also to identify genes of agronomic interest. In this study, we test for evidence of positive selection at the DNA sequence level in a set of candidate genes previously identified in a genome-wide scan for genotypic evidence of selection during the evolution of cultivated sunflower. In the majority of cases, we were able to confirm the effects of selection in shaping diversity at these loci. Notably, the genes that were found to be under selection via our sequence-based analyses were devoid of variation in the cultivated sunflower gene pool. This result confirms a possible strategy for streamlining the search for adaptively-important loci process by pre-screening the derived population to identify the strongest candidates before sequencing them in the ancestral population

    Selection on Crop-Derived Traits and QTL in Sunflower (Helianthus annuus) Crop-Wild Hybrids under Water Stress

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    Locally relevant conditions, such as water stress in irrigated agricultural regions, should be considered when assessing the risk of crop allele introgression into wild populations following hybridization. Although research in cultivars has suggested that domestication traits may reduce fecundity under water stress as compared to wild-like phenotypes, this has not been investigated in crop-wild hybrids. In this study, we examine phenotypic selection acting on, as well as the genetic architecture of vegetative, reproductive, and physiological characteristics in an experimental population of sunflower crop-wild hybrids grown under wild-like low water conditions. Crop-derived petiole length and head diameter were favored in low and control water environments. The direction of selection differed between environments for leaf size and leaf pressure potential. Interestingly, the additive effect of the crop-derived allele was in the direction favored by selection for approximately half the QTL detected in the low water environment. Selection favoring crop-derived traits and alleles in the low water environment suggests that a subset of these alleles would be likely to spread into wild populations under water stress. Furthermore, differences in selection between environments support the view that risk assessments should be conducted under multiple locally relevant conditions

    A target enrichment method for gathering phylogenetic information from hundreds of loci: An example from the Compositae.

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    UnlabelledPremise of the studyThe Compositae (Asteraceae) are a large and diverse family of plants, and the most comprehensive phylogeny to date is a meta-tree based on 10 chloroplast loci that has several major unresolved nodes. We describe the development of an approach that enables the rapid sequencing of large numbers of orthologous nuclear loci to facilitate efficient phylogenomic analyses. •Methods and resultsWe designed a set of sequence capture probes that target conserved orthologous sequences in the Compositae. We also developed a bioinformatic and phylogenetic workflow for processing and analyzing the resulting data. Application of our approach to 15 species from across the Compositae resulted in the production of phylogenetically informative sequence data from 763 loci and the successful reconstruction of known phylogenetic relationships across the family. •ConclusionsThese methods should be of great use to members of the broader Compositae community, and the general approach should also be of use to researchers studying other families

    Video feedback intervention for cognitively impaired older drivers: A randomized clinical trial

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    Introduction: This clinical trial aimed to determine whether in-car video feedback about unsafe driving events (UDE) to cognitively impaired older drivers and family members leads to a reduction in such driving behaviors. Methods: We randomized 51 cognitively impaired older drivers to receive either (1) a weekly progress report with recommendations and access to their videos, or (2) video monitoring alone without feedback over 3 months. Results: UDE frequency/1000 miles was reduced by 12% in feedback (rate ratio [RR] = 0.88, 95% confidence interval [CI] = .58-1.34), while remaining constant with only monitoring (RR = 1.01, 95% CI = .68-1.51). UDE severity/1000 miles was reduced by 37% in feedback (RR = 0.63, 95% CI = .31-1.27), but increased by 40% in monitoring (RR = 1.40, 95% CI = .68-2.90). Cognitive impairment moderated intervention effects ( Discussion: Results suggest the potential to improve driving safety among mild cognitively impaired older drivers using a behavior modification approach aimed at problem behaviors detected in their natural driving environment

    Measuring Transit Signal Recovery in the Kepler Pipeline II: Detection Efficiency as Calculated in One Year of Data

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    The Kepler planet sample can only be used to reconstruct the underlying planet occurrence rate if the detection efficiency of the Kepler pipeline is known, here we present the results of a second experiment aimed at characterising this detection efficiency. We inject simulated transiting planet signals into the pixel data of ~10,000 targets, spanning one year of observations, and process the pixels as normal. We compare the set of detections made by the pipeline with the expectation from the set of simulated planets, and construct a sensitivity curve of signal recovery as a function of the signal-to-noise of the simulated transit signal train. The sensitivity curve does not meet the hypothetical maximum detection efficiency, however it is not as pessimistic as some of the published estimates of the detection efficiency. For the FGK stars in our sample, the sensitivity curve is well fit by a gamma function with the coefficients a = 4.35 and b = 1.05. We also find that the pipeline algorithms recover the depths and periods of the injected signals with very high fidelity, especially for periods longer than 10 days. We perform a simplified occurrence rate calculation using the measured detection efficiency compared to previous assumptions of the detection efficiency found in the literature to demonstrate the systematic error introduced into the resulting occurrence rates. The discrepancies in the calculated occurrence rates may go some way towards reconciling some of the inconsistencies found in the literature.Comment: 13 pages, 7 figures, 1 electronic table, accepted by Ap

    Physical activity self-management interventions for adults with spinal cord injury: Part 2 – Exploring the generalizability of findings from research to practice

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    Despite the benefits associated with regular participation in physical activity, individuals with spinal cord injury (SCI) remain insufficiently active. The ability to self-manage participation may increase physical activity levels, but only if self-management interventions can be implemented in the ‘real world’. The purpose of this review was to examine the degree to which authors of published studies of LTPA self-management interventions for individuals with SCI have reported on factors that could increase the likelihood of translating this research into practice. A systematic search of five databases was conducted, yielding 33 eligible studies representing 31 interventions. Each intervention was assessed using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) Framework and the PRECIS-2 (PRagmatic-Explanatory Continuum Indicator Summary) tool. The most commonly reported RE-AIM dimensions were Effectiveness (51.0% of interventions) and Reach (18.5%), followed by Implementation (14.2%), Maintenance (13.8%), and Adoption (4.0%). Overall, interventions were scored as primarily explanatory in five of the nine PRECIS-2 domains (recruitment, primary analysis, organization, flexibility [delivery], follow-up) and primarily pragmatic in one domain (setting). These findings suggest that while some LTPA self-management interventions for individuals with SCI are intended to be translated to real world settings, limited information is available to understand the degree to which this has been accomplished. Enhanced reporting of factors that could increase the likelihood of translating these interventions into practice is recommended

    Physical activity self-management interventions for adults with spinal cord injury: Part 1–A systematic review of the use and effectiveness of behavior change techniques

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    Objectives: To determine which behavior change techniques (BCTs) have been used within leisure time physical activity (LTPA) self-management interventions for persons with spinal cord injury (SCI), and which BCTs were effective for improving LTPA behavior and/or its antecedents. Design: Systematic review informed by the PRISMA guidelines. Methods: A comprehensive literature search was conducted using five databases. Study characteristics were extracted from included articles and intervention descriptions were coded using the BCT Taxonomy V.1. Effectiveness and maintenance of BCTs as well as the level of behavior change theory use in the design of interventions were examined within experimental studies. Results: Thirty-one unique studies were included, 16 of which had an experimental design. Across all 31 studies, a total of 222 BCTs were identified, representing 32 out of a possible 93 BCTs. The most commonly used BCTs related to the core components of self-management (i.e., education, training/rehearsal of psychological strategies, and social support). Examination of the 16 experimental studies revealed that the use of BCTs corresponding to core self-management components were related to significant improvements and maintenance of LTPA outcomes, regardless of the number of BCTs used. Conclusions: This review offers a glimpse into the mechanisms by which self-management interventions lead to behavior change; however, more research is needed to explore and evaluate other elements (e.g., theory use, tailoring, dose, mode of delivery, and provider) that may comprise effective LTPA self-management interventions for persons with SCI. PROSPERO registration number: CRD42016037531

    Measuring Transit Signal Recovery in the Kepler Pipeline. III. Completeness of the Q1-Q17 DR24 Planet Candidate Catalogue, with Important Caveats for Occurrence Rate Calculations

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    With each new version of the Kepler pipeline and resulting planet candidate catalogue, an updated measurement of the underlying planet population can only be recovered with an corresponding measurement of the Kepler pipeline detection efficiency. Here, we present measurements of the sensitivity of the pipeline (version 9.2) used to generate the Q1-Q17 DR24 planet candidate catalog (Coughlin et al. 2016). We measure this by injecting simulated transiting planets into the pixel-level data of 159,013 targets across the entire Kepler focal plane, and examining the recovery rate. Unlike previous versions of the Kepler pipeline, we find a strong period dependence in the measured detection efficiency, with longer (>40 day) periods having a significantly lower detectability than shorter periods, introduced in part by an incorrectly implemented veto. Consequently, the sensitivity of the 9.2 pipeline cannot be cast as a simple one-dimensional function of the signal strength of the candidate planet signal as was possible for previous versions of the pipeline. We report on the implications for occurrence rate calculations based on the Q1-Q17 DR24 planet candidate catalog and offer important caveats and recommendations for performing such calculations. As before, we make available the entire table of injected planet parameters and whether they were recovered by the pipeline, enabling readers to derive the pipeline detection sensitivity in the planet and/or stellar parameter space of their choice.Comment: 8 pages, 5 figures, full electronic version of Table 1 available at the NASA Exoplanet Archive; accepted by ApJ May 2nd, 201

    Evaluation of naturalistic driving behavior using in-vehicle monitoring technology in preclinical and early Alzheimer\u27s disease

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    Cognitive impairment is a significant risk factor for hazardous driving among older drivers with Alzheimer\u27s dementia, but little is known about how the driving behavior of mildly symptomatic compares with those in the preclinical, asymptomatic phase of Alzheimer\u27s disease (AD). This study utilized two in-car technologies to characterize driving behavior in symptomatic and preclinical AD. The goals of this pilot study were to (1) describe unsafe driving behaviors in individuals with symptomatic early AD using G-force triggered video capture and (2) compare the driving habits of these symptomatic AD drivers to two groups of cognitively normal drivers, those with and those without evidence of cerebral amyloidosis (CN/A+ and CN/A-) using a global positioning system (GPS) datalogger. Thirty-three drivers (aged 60+ years) were studied over 3 months. G-force triggered video events captured instances of near-misses/collisions, traffic violations, risky driver conduct, and driving fundamentals. GPS data were sampled every 30 s and all instances of speeding, hard braking, and sudden acceleration were recorded. For the early AD participants, video capture identified driving unbelted, late response, driving too fast for conditions, traffic violations, poor judgment, and not scanning intersections as the most frequently occurring safety errors. When evaluating driving using the GPS datalogger, hard breaking events occurred most frequently on a per trip basis across all three groups. The CN/A+ group had the lowest event rate across all three event types with lower instances of speeding. Slower psychomotor speed (Trail Making Part A) was associated with fewer speeding events, more hard acceleration events, and more overall events. GPS tracked instances of speeding were correlated with total number of video-captured near-collisions/collisions and driving fundamentals. Results demonstrate the utility of electronic monitoring to identify potentially unsafe driving events in symptomatic and preclinical AD. Results suggest that drivers with preclinical AD may compensate for early, subtle cognitive changes by driving more slowly and cautiously than healthy older drivers or those with cognitive impairment. Self-regulatory changes in driving behavior appear to occur in the preclinical phase of AD, but safety concerns may not arise until symptoms of cognitive impairment emerge and the ability to self-monitor declines
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