621 research outputs found

    Investigations Of The Forgotten Geum: Genetic Diversity And Population Biology Of Geum Geniculatum Michaux, Bent Avens

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    Geum geniculatum Michx., bent avens, is a perennial herb that is endemic to high elevations of three mountaintops between North Carolina and Tennessee. While geographically restricted, some populations have been reported to have thousands of individuals. Thorough surveys have been performed for G. geniculatum; however, some sites have not been visited in over a decade and formal biological studies are lacking. In order to address the needs to understand life history, pollination biology and genetic diversity 1) 13 sub-populations were censused, 2) a long-term demography study was established at one population, 3) an insect visitor survey using time-lapse camera was performed and 4) a population genetics study was performed. Results of censusing suggest the most robust populations occur along stream banks with 90 to 95% canopy cover; however, the plant can also withstand varying habitat including grassy balds and trails. Overall, population sizes appear smaller than previously reported. The first-year demography data, while only established for one population, will provide a baseline to understand life history traits for the species and population viability of the smallest metapopulation. The genetic results suggest G. geniculatum has high genetic diversity and is comprised of three highly structured metapopulations with moderate differentiation between them. These data can be utilized by land managers and future researchers to conserve and manage the species along with guiding future research questions

    Rock pool mosquito ecology of the southern Appalachian Mountains

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    The North American rock pool mosquito, Aedes atropalpus (Coquillet) (Diptera: Culicidae), isprimarily a non-biting species of no perceived threat to public health. The species uses riverine rock pools for immature development and coinhabits the pools with an invasive disease vector, Aedes japonicus japonicus (Theobald) in the United States (U.S.). Since the establishment of the invasive species in the United States in the 1990’s, several reports of reductions in Ae.atropalpus abundance have led to the hypothesis that the native species is being displaced by theinvasive one. The rock pool system remains largely undescribed, limiting our overallunderstanding of ecological interactions between mosquito species in the system. Here weconducted two studies with the unified objective of improving our fundamental knowledge ofrock pool ecology. First, we conducted a field study to describe rock pool communities andanalyze the seasonality of rock pool mosquitoes. Aedes j. japonicus was present in rock pools atboth sites year-round, with overwintering larvae collected in January and winter hatchlingsobserved in February and March. Early season hatching of Ae. j. japonicus allowed the presence of late instar larvae in pools when the first Ae. atropalpus eggs hatched for the season, creatingpotential for stage-dependent competition between the two species. Such asymmetric competition may be an important factor in the reduction of Ae. atropalpus populations. We also conducted a laboratory study aimed at understanding the impact of developmental temperature on Ae. atropalpus fitness. We measured common fitness correlates to predict the finite population growth rate for the species at three ecologically relevant temperature ranges. The results illustrate that the fitness of the species suffers at relatively cold temperatures where Ae. j. japonicus is commonly found in high relative abundances, but also that the optimal developmental temperature for the native species may be close to that of Ae. j. japonicus. Thecombined results of these laboratory and field studies reinforce prior observations of theimportance of temperature in the invasion ecology of Ae. j. japonicus and reveal novel observations that will inform further study of the system

    A study of the relation between the type of house and the location for the home activities of preschool children

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    The growing interest, during the last few years, in the housing needs and preferences of families has been particularly timely in view of the millions of dollars now being spent on housing. The statistical phase of the four regional rural housing surveys, which was recently completed, has made available a fund of information on the kind, scope, and frequency of household activities carried on by farm families in different parts of the country. The studies have also revealed preferences of the homemaker for the location of activities as well as for other house design features.1 Relatively little information was collected in these regional surveys in relation to the home activities of preschool children and the usual location for these activities. In the North Central study, there is a statement, "Children's activities and those adult activities related to children were omitted, not because they were regarded as unimportant, but because the complexity of that problem makes a separate study necessary."

    A Model Of Direct Instruction Applied To Test-Wiseness Instruction For Reading Comprehension Skills

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    This study was designed to determine: (a) the effect of test-wiseness instruction generated from a model of direct instruction on reading comprehension scores of university freshmen, and (b) to determine how test-wiseness instruction generated from a model of di­rect instruction interacts with the gender of university freshmen

    Narrative-based computational modelling of the Gp130/JAK/STAT signalling pathway.

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    BACKGROUND: Appropriately formulated quantitative computational models can support researchers in understanding the dynamic behaviour of biological pathways and support hypothesis formulation and selection by "in silico" experimentation. An obstacle to widespread adoption of this approach is the requirement to formulate a biological pathway as machine executable computer code. We have recently proposed a novel, biologically intuitive, narrative-style modelling language for biologists to formulate the pathway which is then automatically translated into an executable format and is, thus, usable for analysis via existing simulation techniques. RESULTS: Here we use a high-level narrative language in designing a computational model of the gp130/JAK/STAT signalling pathway and show that the model reproduces the dynamic behaviour of the pathway derived by biological observation. We then "experiment" on the model by simulation and sensitivity analysis to define those parameters which dominate the dynamic behaviour of the pathway. The model predicts that nuclear compartmentalisation and phosphorylation status of STAT are key determinants of the pathway and that alternative mechanisms of signal attenuation exert their influence on different timescales. CONCLUSION: The described narrative model of the gp130/JAK/STAT pathway represents an interesting case study showing how, by using this approach, researchers can model biological systems without explicitly dealing with formal notations and mathematical expressions (typically used for biochemical modelling), nevertheless being able to obtain simulation and analysis results. We present the model and the sensitivity analysis results we have obtained, that allow us to identify the parameters which are most sensitive to perturbations. The results, which are shown to be in agreement with existing mathematical models of the gp130/JAK/STAT pathway, serve us as a form of validation of the model and of the approach itself

    Single-inhaler triple therapy fluticasone furoate/umeclidinium/vilanterol versus fluticasone furoate/vilanterol and umeclidinium/vilanterol in patients with COPD: results on cardiovascular safety from the IMPACT trial

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    BACKGROUND: This analysis of the IMPACT study assessed the cardiovascular (CV) safety of single-inhaler triple therapy with fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus FF/VI and UMEC/VI dual therapy. METHODS: IMPACT was a 52-week, randomized, double-blind, multicenter Phase III study comparing the efficacy and safety of FF/UMEC/VI 100/62.5/25 mcg with FF/VI 100/25 mcg or UMEC/VI 62.5/25 mcg in patients ≥40 years of age with symptomatic chronic obstructive pulmonary disease (COPD) and ≥1 moderate/severe exacerbation in the previous year. The inclusion criteria for the study were intentionally designed to permit the enrollment of patients with significant concurrent CV disease/risk. CV safety assessments included proportion of patients with and exposure-adjusted rates of on-treatment CV adverse events of special interest (CVAESI) and major adverse cardiac events (MACE), as well as time-to-first (TTF) CVAESI, and TTF CVAESI resulting in hospitalization/prolonged hospitalization or death. RESULTS: Baseline CV risk factors were similar across treatment groups. Overall, 68% of patients (n = 7012) had ≥1 CV risk factor and 40% (n = 4127) had ≥2. At baseline, 29% of patients reported a current/past cardiac disorder and 58% reported a current/past vascular disorder. The proportion of patients with on-treatment CVAESI was 11% for both FF/UMEC/VI and UMEC/VI, and 10% for FF/VI. There was no statistical difference for FF/UMEC/VI versus FF/VI or UMEC/VI in TTF CVAESI (hazard ratio [HR]: 0.98, 95% confidence interval [CI]: 0.85, 1.11; p = 0.711 and HR: 0.92, 95% CI: 0.78, 1.08; p = 0.317, respectively) nor TTF CVAESI leading to hospitalization/prolonged hospitalization or death (HR: 1.19, 95% CI: 0.93, 1.51; p = 0.167 and HR: 0.96, 95% CI: 0.72, 1.27; p = 0.760, respectively). On-treatment MACE occurred in ≤3% of patients across treatment groups, with similar prevalence and rates between treatments. CONCLUSIONS: In a symptomatic COPD population with a history of exacerbations and a high rate of CV disease/risk, the proportion of patients with CVAESI and MACE was 10-11% and 1-3%, respectively, across treatment arms, and the risk of CVAESI was low and similar across treatment arms. There was no statistically significant increased CV risk associated with the use of FF/UMEC/VI versus FF/VI or UMEC/VI, and UMEC/VI versus FF/VI. TRIAL REGISTRATION: NCT02164513 (GSK study number CTT116855)

    Mendelian randomization study of B-type natriuretic peptide and type 2 diabetes: evidence of causal association from population studies

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    <p>Background: Genetic and epidemiological evidence suggests an inverse association between B-type natriuretic peptide (BNP) levels in blood and risk of type 2 diabetes (T2D), but the prospective association of BNP with T2D is uncertain, and it is unclear whether the association is confounded.</p> <p>Methods and Findings: We analysed the association between levels of the N-terminal fragment of pro-BNP (NT-pro-BNP) in blood and risk of incident T2D in a prospective case-cohort study and genotyped the variant rs198389 within the BNP locus in three T2D case-control studies. We combined our results with existing data in a meta-analysis of 11 case-control studies. Using a Mendelian randomization approach, we compared the observed association between rs198389 and T2D to that expected from the NT-pro-BNP level to T2D association and the NT-pro-BNP difference per C allele of rs198389. In participants of our case-cohort study who were free of T2D and cardiovascular disease at baseline, we observed a 21% (95% CI 3%-36%) decreased risk of incident T2D per one standard deviation (SD) higher log-transformed NT-pro-BNP levels in analysis adjusted for age, sex, body mass index, systolic blood pressure, smoking, family history of T2D, history of hypertension, and levels of triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. The association between rs198389 and T2D observed in case-control studies (odds ratio = 0.94 per C allele, 95% CI 0.91-0.97) was similar to that expected (0.96, 0.93-0.98) based on the pooled estimate for the log-NT-pro-BNP level to T2D association derived from a meta-analysis of our study and published data (hazard ratio = 0.82 per SD, 0.74-0.90) and the difference in NT-pro-BNP levels (0.22 SD, 0.15-0.29) per C allele of rs198389. No significant associations were observed between the rs198389 genotype and potential confounders.</p> <p>Conclusions: Our results provide evidence for a potential causal role of the BNP system in the aetiology of T2D. Further studies are needed to investigate the mechanisms underlying this association and possibilities for preventive interventions.</p&gt

    Reduction in All-Cause Mortality with Fluticasone Furoate/Umeclidinium/Vilanterol in COPD Patients

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    Rationale: The IMPACT trial demonstrated a significant reduction in all-cause mortality (ACM) risk with fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus FF/VI or UMEC/VI in patients with COPD at risk of future exacerbations. 574 patients were censored from the original analysis due to incomplete vital status information. Objective: Report ACM and impact of stepping down therapy, following collection of additional vital status data. Methods: Patients were randomized 2:2:1 to FF/UMEC/VI 100/62.5/25µg, FF/VI 100/25µg or UMEC/VI 62.5/25µg following a run-in on their COPD therapies. Time to ACM was prespecified. Additional vital status data collection and subsequent analyses were performed post hoc. Measurements and Main Results: We report vital status data for 99.6% of the intention-to-treat population (n=10,355), documenting 98(2.36%) deaths on FF/UMEC/VI, 109(2.64%) on FF/VI, and 66(3.19%) on UMEC/VI. For FF/UMEC/VI, the hazard ratio for death was 0.72 (95%CI: 0.53,0.99;P=0.042) versus UMEC/VI and 0.89 (95%CI: 0.67,1.16;P=0.387) versus FF/VI. Independent adjudication confirmed lower rates of cardiovascular and respiratory death, and death associated with the patient’s COPD. Conclusions: In this secondary analysis of an efficacy outcome from the IMPACT trial, once-daily single-inhaler FF/UMEC/VI triple therapy reduced the risk of ACM versus UMEC/VI in patients with symptomatic COPD and a history of exacerbations. Funding: GSK(CTT116855/NCT02164513)
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