63 research outputs found

    The Effect of Environmental Perturbations on the Plant Phyllosphere Microbiome

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    Applying ecological concepts to microbial communities has proved to be challenging, often revolving around the relative importance of stochastic and deterministic processes applied heterogeneously across the habitat in time or space. The phyllosphere is the aboveground surface of plants on which microbial communities, composed primarily of Bacteria, but also including Archaea and microbial eukaryotes, exist and is characterized by stochastic immigration balanced with strong selective forces. Variation in bacterial community composition was characterized across space and time, with special attention given to the exposure of phyllosphere communities to rain as a plausible mechanism of ecological disturbance. Bacterial communities were characterized through targeted Illumina sequencing of the 16S rRNA taxonomic marker gene. Biogeographic patterns of bacteria in the phyllosphere were found to be evident from southern magnolia (Magnolia grandiflora) trees 1-452 m apart in a small forest plot. A significant relationship between canopy cover and tree elevation and differences in bacterial abundances but not in bacterial incidence, suggesting that bacterial abundance and incidence in the phyllosphere is shaped by different assembly mechanisms. More broadly, this suggests that environmental parameters and neutral forces may influence spatial patterns in the phyllosphere, even at small spatial scales. Separately, the effects of rain were investigated in both short-term and long-term contexts. First, rain as a short-term disturbance was contrasted against long-term seasonal changes to the phyllosphere bacterial community of broadleaf cattail (Typha latifolia) plants collected across an entire year, specifically targeting days before rain events and up to five days after. Secondly, the effect of rain throughout the tree canopy of M. grandiflora was investigated. Across both studies, rain did not appear to have any effect on bacterial community richness, evenness, novel species accumulation, or composition. Instead, longer seasonal trends determined diversity and compositional patterns in T. latifolia, while canopy structure had the strongest influence on M. grandiflora. These findings suggest that rain does not act as an ecological disturbance towards the phyllosphere bacterial community and that short-term abiotic disruptions may exert minimal influence on its composition and development in comparison to longer trends or spatial heterogeneity which likely influence the plant host as well

    Re-visiting Meltsner: Policy Advice Systems and the Multi-Dimensional Nature of Professional Policy Analysis

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    10.2139/ssrn.15462511-2

    Transcriptome-wide association study of breast cancer risk by estrogen-receptor status

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    Previous transcriptome-wide association studies (TWAS) have identified breast cancer risk genes by integrating data from expression quantitative loci and genome-wide association studies (GWAS), but analyses of breast cancer subtype-specific associations have been limited. In this study, we conducted a TWAS using gene expression data from GTEx and summary statistics from the hitherto largest GWAS meta-analysis conducted for breast cancer overall, and by estrogen receptor subtypes (ER+ and ER-). We further compared associations with ER+ and ER- subtypes, using a case-only TWAS approach. We also conducted multigene conditional analyses in regions with multiple TWAS associations. Two genes, STXBP4 and HIST2H2BA, were specifically associated with ER+ but not with ER- breast cancer. We further identified 30 TWAS-significant genes associated with overall breast cancer risk, including four that were not identified in previous studies. Conditional analyses identified single independent breast-cancer gene in three of six regions harboring multiple TWAS-significant genes. Our study provides new information on breast cancer genetics and biology, particularly about genomic differences between ER+ and ER- breast cancer.Peer reviewe

    Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

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    Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

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    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    How multiple weather conditions can combine to affect the whole microbial community

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    Changes in Microdiversit

    A hide–search game

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