2,678 research outputs found

    Shifts in Myxomycete Community Structure in Selected Microhabitats Across Nutrient Treatments in a Lowland Tropical Forest of Panama

    Get PDF
    Myxomycetes (plasmodial slime molds) are abundant amoeboid predators of bacteria and other microorganisms. They are found worldwide, largely in association with decaying plant material in terrestrial habitats. Their consumption of bacterial prey puts microbial predators such as myxomycetes in a key position in various ecosystem processes wherein they help regulate the flow of nutrients (e.g., N and C) through the ecosystem. The importance of microbial predators in nutrient cycling and plant productivity is well established. Given the extent to which tropical ecosystems influence global nutrient fluxes, along with the ecologically significant role that myxomycetes play in these processes, there is a pressing need to learn more about this understudied community. This dissertation comprises an important first step toward developing an understanding of the ecological role of myxomycetes, with two major contributions. Identifying species is a fundamental step toward characterizing the diversity of a community. Given the unique challenge of identifying species of myxomycetes imposed by their unique biology, this dissertation begins in chapter two with a review of the myxomycete species concept. The various species concepts used (or potentially used) to identify species of myxomycetes are discussed. In chapter three, the challenges that myxomycete identification pose are described in the context of an ecological study. Therein, the use of a long-term nutrient fertilization experiment is described within which the effects of three major macronutrients, N, P and K on the myxomycete community in a lowland tropical forest of Panama are investigated. Interestingly, very little evidence supports the presence of a nutrient limitation to the myxomycete community, despite the many limitations that have been identified for other groups in this ecosystem (e.g., plants). The unexpected results provide the opportunity to again discuss the complications of species identification and enumeration of myxomycetes for in-depth studies. The results also highlight the unique biology of myxomycetes and provide new insights into their ecology. Finally, in chapter four, a holistic approach is employed to describe a species new to science that was discovered during the course of this dissertation work in Panama. Overall this dissertation highlights the importance of myxomycete taxonomy in an ecological framework

    Pros in Parks: Integrated Programming for Reaching Our Urban Park Operations Audience

    Get PDF
    In addition to regular job duties, such as tree care, mulching, irrigation, and pesticide management, urban park workers have faced environmental changes due to drought, wildfires, and West Nile virus. They simultaneously have endured expectations to manage growing, diversifying park usage and limitations on career development. An integrated programming approach is used to provide training to frontline parks department employees in the cities of Arlington and Fort Worth, Texas. Results indicate high levels of adoption of practices, enhanced staff morale, and identification of potential future leaders. The program also introduces an urban audience to the broader array of Extension programming and services

    Combining social network analysis and the NATO Approach Space to define agility. Topic 2: networks and networking

    No full text
    This paper takes the NATO SAS-050 Approach Space, a widely accepted model of command and control, and gives each of its primary axes a quantitative measure using social network analysis. This means that the actual point in the approach space adopted by real-life command and control organizations can be plotted along with the way in which that point varies over time and function. Part 1 of the paper presents the rationale behind this innovation and how it was subject to verification using theoretical data. Part 2 shows how the enhanced approach space was put to use in the context of a large scale military command post exercise. Agility is represented by the number of distinct areas in the approach space that the organization was able to occupy and there was a marked disparity between where the organization thought it should be and where it actually was, furthermore, agility varied across function. The humans in this particular scenario bestowed upon the organization the levels of agility that were observed, thus the findings are properly considered from a socio-technical perspective

    Adaptive genomic structural variation in the grape powdery mildew pathogen, Erysiphe necator.

    Get PDF
    BackgroundPowdery mildew, caused by the obligate biotrophic fungus Erysiphe necator, is an economically important disease of grapevines worldwide. Large quantities of fungicides are used for its control, accelerating the incidence of fungicide-resistance. Copy number variations (CNVs) are unbalanced changes in the structure of the genome that have been associated with complex traits. In addition to providing the first description of the large and highly repetitive genome of E. necator, this study describes the impact of genomic structural variation on fungicide resistance in Erysiphe necator.ResultsA shotgun approach was applied to sequence and assemble the genome of five E. necator isolates, and RNA-seq and comparative genomics were used to predict and annotate protein-coding genes. Our results show that the E. necator genome is exceptionally large and repetitive and suggest that transposable elements are responsible for genome expansion. Frequent structural variations were found between isolates and included copy number variation in EnCYP51, the target of the commonly used sterol demethylase inhibitor (DMI) fungicides. A panel of 89 additional E. necator isolates collected from diverse vineyard sites was screened for copy number variation in the EnCYP51 gene and for presence/absence of a point mutation (Y136F) known to result in higher fungicide tolerance. We show that an increase in EnCYP51 copy number is significantly more likely to be detected in isolates collected from fungicide-treated vineyards. Increased EnCYP51 copy numbers were detected with the Y136F allele, suggesting that an increase in copy number becomes advantageous only after the fungicide-tolerant allele is acquired. We also show that EnCYP51 copy number influences expression in a gene-dose dependent manner and correlates with fungal growth in the presence of a DMI fungicide.ConclusionsTaken together our results show that CNV can be adaptive in the development of resistance to fungicides by providing increasing quantitative protection in a gene-dosage dependent manner. The results of this work not only demonstrate the effectiveness of using genomics to dissect complex traits in organisms with very limited molecular information, but also may have broader implications for understanding genomic dynamics in response to strong selective pressure in other pathogens with similar genome architectures

    How limiting is optical follow-up for fast radio burst applications? Forecasts for radio and optical surveys

    Get PDF
    Fast radio bursts (FRBs) are the first cosmological radio sources that vary on millisecond timescales, which makes them a unique probe of the Universe. Many proposed applications of FRBs require associated redshifts. These can only be obtained by localizing FRBs to their host galaxies and subsequently measuring their redshifts. Upcoming FRB surveys will provide arcsecond localization for many FRBs, not all of which can be followed up with dedicated optical observations. We aim to estimate the fraction of FRB hosts that will be catalogued with redshifts by existing and future optical surveys. We use the population synthesis code frbpoppy to simulate several FRB surveys, and the semi-analytical galaxy formation code GALFORM to simulate their host galaxies. We obtain redshift distributions for the simulated FRBs and the fraction with host galaxies in a survey. Depending on whether FRBs follow the cosmic star formation rate or stellar mass, 20 to 40 per cent of CHIME FRB hosts will be observed in an SDSS-like survey, all at z<0.5z<0.5. The deeper DELVE survey will detect 63 to 85 per cent of ASKAP FRBs found in its coherent search mode. CHIME FRBs will reach z∼3z\sim 3, SKA1-Mid FRBs z∼5z\sim 5, but ground based follow-up is limited to z≲1.5z\lesssim 1.5. We discuss consequences for several FRB applications. If ∼1/2\sim1/2 of ASKAP FRBs have measured redshifts, 1000 detected FRBs can be used to constrain Ωbh70\Omega_\text{b} h_{70} to within ∼10\sim10 per cent at 95 per cent credibility. We provide strategies for optimized follow-up, when building on data from existing surveys. Data and codes are made available.Comment: 18 pages, 16 figures, 4 tables, accepted for publication in MNRAS. Code available at https://github.com/JoschaJ/mockFRBhost

    Establishing a Community of Practice for Doctoral Studies Amidst the COVID-19 Pandemic

    Get PDF
    In this discussion paper, we describe our experience completing the first year of the doctorate in nursing program at a large urban academic centre during the COVID-19 pandemic. We highlight the current nursing shortage and the importance of supporting all nursing students, including nurses in doctoral programs, towards successful graduation. We describe the development of a virtual community of practice incorporating five key strategies: Building community, fostering collaboration, strengthening connection, enhancing creativity, and promoting consistency. We believe that utilizing these strategies will contribute to our success and may be relevant to nursing leaders seeking to support the development of more doctorally prepared nurses. Participation in a community of practice early on in doctoral education will not only better prepare students for success in their program, but also continued success as they progress through their careers. It is important for students to not only make connections with peers in their area of academic study, but to also reach out to peers in other disciplines to improve both individual and interdisciplinary growth. Program administrators and educators can encourage the formation of community of practice among novice doctoral students. This encouragement can be achieved using a virtual platform, or in-person networking opportunities. Inviting incoming graduate students to connect with each other and with students from previous cohorts also fosters community of practice formation. Résumé Dans ce texte de discussion, nous décrivons notre expérience relative à la première année du doctorat en sciences infirmières dans un grand centre universitaire urbain pendant la pandémie de COVID-19. Nous soulignons la pénurie actuelle d’infirmières et l’importance de soutenir toutes les étudiantes en sciences infirmières, y compris les infirmières inscrites à un programme de doctorat, vers la réussite de leurs études. Nous décrivons le développement d’une communauté virtuelle de pratique intégrant cinq stratégies clés : créer une communauté, favoriser la collaboration, renforcer les liens, mettre en valeur la créativité et promouvoir la cohérence. Nous pensons que l’utilisation de ces stratégies contribuera à notre succès et pourrait être pertinente pour les infirmières chefs de file qui cherchent à soutenir le développement d’un plus grand nombre d’infirmières préparées au doctorat. La participation à une communauté de pratique dès le début de la formation doctorale permettra non seulement de mieux préparer les étudiantes à réussir dans leur programme, mais favorisera également leur poursuite d’une carrière fructueuse. Il est important pour les étudiantes d’établir des liens non seulement avec des pairs dans leur domaine d’études universitaires, mais qu’ils entrent également en contact avec des pairs d’autres disciplines pour améliorer à la fois leur croissance individuelle et interdisciplinaire. Les administratrices de programme et les enseignantes peuvent encourager la formation d’une communauté de pratique parmi les doctorantes novices. Cet encouragement peut être réalisé à l’aide d’une plateforme virtuelle ou d’occasions de réseautage en personne. Inviter les étudiantes diplômées à entrer en contact les unes avec les autres et avec les étudiantes des cohortes précédentes favorise également la formation d’une communauté de pratique

    Social Competence Treatment after Traumatic Brain Injury: A Multicenter, Randomized, Controlled Trial of Interactive Group Treatment versus Non-Interactive Treatment

    Get PDF
    Objective To evaluate the effectiveness of a replicable group treatment program for improving social competence after traumatic brain injury (TBI). Design Multicenter randomized controlled trial comparing two methods of conducting a social competency skills program, an interactive group format versus a classroom lecture. Setting Community and Veteran rehabilitation centers. Participants 179 civilian, military, and veteran adults with TBI and social competence difficulties, at least 6 months post-injury. Experimental Intervention Thirteen weekly group interactive sessions (1.5 hours) with structured and facilitated group interactions to improve social competence. Alternative (Control) Intervention Thirteen traditional classroom sessions using the same curriculum with brief supplemental individual sessions but without structured group interaction. Primary Outcome Measure Profile of Pragmatic Impairment in Communication (PPIC), an objective behavioral rating of social communication impairments following TBI. Secondary Outcomes LaTrobe Communication Questionnaire (LCQ), Goal Attainment Scale (GAS), Satisfaction with Life Scale (SWLS), Post-Traumatic Stress Disorder Checklist – (PCL-C), Brief Symptom Inventory 18 (BSI-18), Scale of Perceived Social Self Efficacy (PSSE). Results Social competence goals (GAS) were achieved and maintained for most participants regardless of treatment method. Significant improvements in the primary outcome (PPIC) and two of the secondary outcomes (LCQ and BSI) were seen immediately post-treatment and at 3 months post-treatment in the AT arm only, however these improvements were not significantly different between the GIST and AT arms. Similar trends were observed for PSSE and PCL-C. Conclusions Social competence skills improved for persons with TBI in both treatment conditions. The group interactive format was not found to be a superior method of treatment delivery in this study
    • …
    corecore