2,084 research outputs found

    Evaluating the Effects of Simulated Golf Cart Traffic on Dormant Buffalograss and Turfgrass Colorants

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    Percent green cover will ultimately decrease over time when traffic is applied to dormant buffalograss with turfgrass colorants. Data suggests that an additional five weeks of acceptable green cover can be achieved under high traffic situations when Endurant Premium is applied to dormant turf

    Influence of Fertilizer Source and Rate on Buffalograss Divot Recovery

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    Application of quick-release nitrogen fertilizer increased buffalograss divot recovery. A quick-release fertilizer at 1 lb N/1,000 ft2 resulted in 50% divot recovery 6.3 days quicker compared to the untreated control

    Influence of Simulated Golf Cart Traffic and Nitrogen Rate on Buffalograss Quality

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    Application of 2 and 3 lb N/1,000 ft2 resulted in acceptable buffalograss quality when subjected to simulated golf cart traffic. Across all fertilizer treatments, traffic rates of 8 and 16 passes per week resulted in unacceptable quality ratings for the study duration

    From Random to Regular: Variation in the Patterning of Retinal Mosaics

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    The various types of retinal neurons are each positioned at their respective depths within the retina where they are believed to be assembled as orderly mosaics, in which like-type neurons minimize proximity to one another. Two common statistical analyses for assessing the spatial properties of retinal mosaics include the nearest neighbor analysis, from which an index of their "regularity" is commonly calculated, and the density recovery profile derived from auto-correlation analysis, revealing the presence of an exclusion zone indicative of anti-clustering. While each of the spatial statistics derived from these analyses, the regularity index and the effective radius, can be useful in characterizing such properties of orderly retinal mosaics, they are rarely sufficient for conveying the natural variation in the self-spacing behavior of different types of retinal neurons and the extent to which that behavior generates uniform intercellular spacing across the mosaic. We consider the strengths and limitations of different spatial statistical analyses for assessing the patterning in retinal mosaics, highlighting a number of misconceptions and their frequent misuse. Rather than being diagnostic criteria for determining simply whether a population is "regular", they should be treated as descriptive statistics that convey variation in the factors that influence neuronal positioning. We subsequently apply multiple spatial statistics to the analysis of eight different mosaics in the mouse retina, demonstrating conspicuous variability in the degree of patterning present, from essentially random to notably regular. This variability in patterning has both a developmental as well as a functional significance, reflecting the rules governing the positioning of different types of neurons as the architecture of the retina is assembled (abstract truncated).Comment: 11 Figure

    Clostridium difficile: a healthcare associated infection of unknown significance in adults in sub-Saharan Africa

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    Background: Clostridium difficile infection (CDI) causes a high burden of disease in high-resource healthcare systems, with significant morbidity, mortality and financial implications. CDI is a healthcare-associated infection for which the primary risk factor is antibiotic usage and it is the leading cause of bacterial diarrhoea in HIV infected patients in USA. Little is known about the disease burden of CDI in sub-Saharan Africa, where HIV and healthcare associated infection have a higher prevalence and antibiotic usage is less restricted. Aim: To review published literature on CDI in sub-Saharan Africa, highlighting areas for future research. Methods: English language publications since 1995 were identified from online databases (PubMed, Medline, Google Scholar, SCOPUS) and personal collections of articles, using combinations of keywords to include C. difficile, Africa and HIV. Results: Ten relevant studies were identified. There is considerable variation in methodology to assess for carriage of toxigenic C. difficile and its associations. Eight studies report carriage of toxigenic C. difficile. Three (of four) studies found an association with antibiotic usage. One (of four) studies showed an association with HIV infection. One study showed no association with degree of immunosuppression in HIV. Two (of three) studies showed an association between carriage of toxigenic C. difficile and diarrhoeal illness. Conclusion: Whilst the carriage of toxigenic C. difficile is well described in sub-Saharan Africa, the impact of CDI in the Region remains poorly l understood and warrants high quality research

    A global synthesis of fire effects on pollinators

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    Understanding fire effects on pollinators is critical in the context of fire regime changes and the global pollination crisis. Through a systematic and quantitative review of the literature, we provide the first global assessment of pollinator responses to fire. We hypothesize that pollinators increase after fire and during the early postfire succession stages; however, high fire frequency has the opposite effect, decreasing pollinators. Location: Terrestrial ecosystems, excluding Antarctica. Time period: Data collected from 1973 to 2017. Major taxa studied: Insects (Coleoptera, Diptera, Hymenoptera and Lepidoptera) and a few bird species. Methods: We first compiled available studies across the globe that assessed fire effects on pollinator communities. Then, by means of hierarchical meta-analyses, we evaluated how different fire regime parameters (fire frequency, postfire time and fire type) and habitat characteristics affect the abundance and richness of animals that act as pollinators. We also explored to what extent the responses vary among taxa groups and life history traits of pollinators (sociality system, nest location and feeding specialization), and among biomes. The overall effect size of fire on pollinator abundance and richness across all studies was positive. Fire effect was especially clear and significant in early postfire communities, after wildfires, and for Hymenoptera. Taxonomic resolution influenced fire effects, where only studies at the species/genus and family levels showed significant effects. The main exceptions were recurrent fires that showed a negative effect, and especially wildfire effects on Lepidoptera abundance that showed a significant negative response. Main conclusions: Pollinators tend to be promoted after a wildfire event. However, short fire intervals may threat pollinators, and especially lepidopterans. Given the current fire regime changes at the global scale, it is imperative to monitor postfire pollinators across many ecosystems, as our results suggest that fire regime is critical in determining the dynamics of pollinator communities.Fil: Carbone, Lucas Manuel. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Tavella, Julia Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Pausas, Juli G.. Universidad de Valencia; EspañaFil: Aguilar, Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin
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