369 research outputs found

    Spatial Selectivity in Cochlear Implants: Effects of Asymmetric Waveforms and Development of a Single-Point Measure.

    Get PDF
    Three experiments studied the extent to which cochlear implant users' spatial selectivity can be manipulated using asymmetric waveforms and tested an efficient method for comparing spatial selectivity produced by different stimuli. Experiment 1 measured forward-masked psychophysical tuning curves (PTCs) for a partial tripolar (pTP) probe. Maskers were presented on bipolar pairs separated by one unused electrode; waveforms were either symmetric biphasic ("SYM") or pseudomonophasic with the short high-amplitude phase being either anodic ("PSA") or cathodic ("PSC") on the more apical electrode. For the SYM masker, several subjects showed PTCs consistent with a bimodal excitation pattern, with discrete excitation peaks on each electrode of the bipolar masker pair. Most subjects showed significant differences between the PSA and PSC maskers consistent with greater masking by the electrode where the high-amplitude phase was anodic, but the pattern differed markedly across subjects. Experiment 2 measured masked excitation patterns for a pTP probe and either a monopolar symmetric biphasic masker ("MP_SYM") or pTP pseudomonophasic maskers where the short high-amplitude phase was either anodic ("TP_PSA") or cathodic ("TP_PSC") on the masker's central electrode. Four of the five subjects showed significant differences between the masker types, but again the pattern varied markedly across subjects. Because the levels of the maskers were chosen to produce the same masking of a probe on the same channel as the masker, it was correctly predicted that maskers that produce broader masking patterns would sound louder. Experiment 3 exploited this finding by using a single-point measure of spread of excitation to reveal significantly better spatial selectivity for TP_PSA compared to TP_PSC maskers

    Responses of young Punica granatum plants under four different water regimes

    Get PDF
    We studied the effect of four irrigation treatments, expressed as fractions (1.3, 1.0, 0.7 and 0.3) of crop evapotranspiration (ETc), on the growth of young pomegranate plants in central Chile (32°32’ S and 71°06’ W). We evaluated the effect of the four treatments on canopy volume (CV) during two growing seasons. For 28 days during the second growing season, we evaluated soil moisture content (0), the soil-moisture depletion factor (p), trunk cumulative growth (TCG), trunk growth rate (TGR) and maximum daily trunk shrinkage (MDS). We found relationships between CV and TCG and between CV and TGR. There were no differences in MDS among the irrigation treatments. We observed significant water stress in plants in the 0.3 ETc treatment (p = 0.47). The highest growth was observed in plants in the 1.3 ETc treatment, which suggests that the crop coefficient (Kc) was underestimated.Se estudió el efecto de cuatro tratamientos de riego como fracciones (1.3, 1.0, 0.7 y 0.3) de la evapotranspiración de cultivo (ETc) sobre variables de crecimiento de plantas jóvenes de granado en Chile central (provincia de Petorca) (32°32’ S and 71°06’ W). Se evaluó el volumen de copa (CV) durante las dos primeras temporadas de crecimiento de las plantas. En la segunda temporada de crecimiento se determinó durante 28 días el contenido de humedad del suelo (0), la fracción de agotamiento de la humedad del suelo (p), el crecimiento acumulado del tronco (TCG), la tasa de crecimiento del tronco (TGR) y contracción máxima del tronco (MDS). Existió relación entre el CV y las variables de crecimiento del tronco (TCG y TGR). La MDS no presentó diferencias entre los tratamientos. Se evidenció un estrés significativo cuando se rego un 30% de la evapotranspiración de cultivo (ETc), bajo estas condiciones las plantas fueron sometidas valores de (p) de 0.47. El mayor crecimiento fue observado con 1.3ETc por lo que se considera que se subestimo el valor de coeficiente de cultivo (kc) en el presente estudio

    Tool for eliminating dog-mediated human rabies through mass dog vaccination campaigns

    Get PDF
    The World Health Organization and collaborating agencies have set the goal of eliminating dog-mediated human rabies by 2030. Building on experience with rabies endemic countries, we constructed a user-friendly tool to help public health officials plan the resources needed to achieve this goal through mass vaccination of dogs

    Efecto de inmersiones en calcio sobre peteca en limones amarillos y plateados, cosechados despu\ue9s de una lluvia y almacenados en refrigeraci\uf3n

    Get PDF
    Peteca (rind pitting) is a physiological disorder that produces decay in lemon peels ( Citrus limon (L.) Burm. f.), affecting fruit quality. The objective of this assay was to evaluate in lemons cv. Genova, with yellow and silver green rinds, , the effect of post-harvest calcium immersion, on rind pitting incidence in cold stored fruit after rainfall induced stress. The fruit was harvested, 3, 6 and 9 days after a rainfall, and dipped in calcium solutions: calcium nitrate 0.8%; calcium chloride at 0.5% and 1% of commercial product, and later stored at 7\ub0C for 0, 15, 30 and 45 days. The presence of rind pitting and calcium percentage in the rind was evaluated. Also, histological analyse of fruit affected with rind pitting was carried out. At each harvest date, lemons harvested with yellow rinds developed more rind pitting than silver green lemons, and extending days after harvest rainfall reduced rind pitting intensity. Yellow lemons harvested three days after a rainfall, treated with 1% of commercial calcium chloride product, didn't show development of petaca compared with the control. It was not possible to associate the calcium level of the rind with rind pitting development.La peteca es un desorden fisiol\uf3gico que produce da\uf1o en la corteza de limones ( Citrus limon (L.) Burm. f.), afectando la calidad de la fruta. El objetivo de este ensayo fue evaluar en limones cv. G\ue9nova, amarillos y plateados, el efecto de inmersiones de calcio en poscosecha, sobre la incidencia de peteca en almacenaje refrigerado de frutos sometidos a un estr\ue9s producido por lluvia. La fruta fue cosechada 3, 6 y 9 d\uedas despu\ue9s de una lluvia, y sometida a una inmersi\uf3n, en soluciones de: nitrato de calcio 0,8%, cloruro de calcio al 0,5% y 1% de producto comercial, siendo posteriormente almacenada a 7\ub0C, por 0; 15; 30 y 45 d\uedas. Se evalu\uf3 presencia de peteca y contenido de calcio total en la corteza. Adem\ue1s, se efectu\uf3 un an\ue1lisis histol\uf3gico de los frutos que presentaron peteca. En cada fecha de cosecha por separado, los limones amarillos presentaron mayor incidencia de peteca que los plateados, y a medida que la cosecha se distanci\uf3 de la lluvia, el desorden redujo su intensidad. Limones amarillos cosechados tres d\uedas despu\ue9s de una lluvia, tratados con cloruro de calcio 1% de producto comercial no mostraron desarrollo de peteca comparado con el testigo. No fue posible asociar contenido de calcio en la corteza con desarrollo de peteca en los frutos

    Socioeconomic factors associated with antimicrobial resistance of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli in Chilean hospitals (2008-2017).

    Get PDF
    OBJECTIVE: To identify socioeconomic factors associated with antimicrobial resistance of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli in Chilean hospitals (2008-2017). METHODS: We reviewed the scientific literature on socioeconomic factors associated with the emergence and dissemination of antimicrobial resistance. Using multivariate regression, we tested findings from the literature drawing from a longitudinal dataset on antimicrobial resistance from 41 major private and public hospitals and a nationally representative household survey in Chile (2008-2017). We estimated resistance rates for three priority antibiotic-bacterium pairs, as defined by the Organisation for Economic Co-operation and Development; i.e., imipenem and meropenem resistant P. aeruginosa, cloxacillin resistant S. aureus, and cefotaxime and ciprofloxacin resistant E. coli. RESULTS: Evidence from the literature review suggests poverty and material deprivation are important risk factors for the emergence and transmission of antimicrobial resistance. Most studies found that worse socioeconomic indicators were associated with higher rates of antimicrobial resistance. Our analysis showed an overall antimicrobial resistance rate of 32.5%, with the highest rates for S. aureus (40.6%) and the lowest for E. coli (25.7%). We found a small but consistent negative association between socioeconomic factors (income, education, and occupation) and overall antimicrobial resistance in univariate (p < 0.01) and multivariate analyses (p < 0.01), driven by resistant P. aeruginosa and S. aureus. CONCLUSION: Socioeconomic factors beyond health care and hospital settings may affect the emergence and dissemination of antimicrobial resistance. Preventing and controlling antimicrobial resistance requires efforts above and beyond reducing antibiotic consumption

    Costs and effectiveness of alternative dog vaccination strategies to improve dog population coverage in rural and urban settings during a rabies outbreak.

    Get PDF
    Dog-rabies elimination programs have typically relied upon parenteral vaccination at central-point locations; however, dog-ownership practices, accessibility to hard-to-reach sub-populations, resource limitations, and logistics may impact a country's ability to reach the 70% coverage goal recommended by the World Organization for Animal Health (OIE) and World Health Organization (WHO). Here we report the cost-effectiveness of different dog-vaccination strategies during a dog-rabies outbreak in urban and peri-urban sections of Croix-des-Bouquets commune of the West Department, Haiti, in 2016. Three strategies, mobile static point (MSP), mobile static point with capture-vaccinate-release (MSP?+?CVR), and door-to-door vaccination with oral vaccination (DDV?+?ORV), were applied at five randomly assigned sites and assessed for free-roaming dog vaccination coverage and total population coverage. A total of 7065 dogs were vaccinated against rabies during the vaccination campaign. Overall, free-roaming dog vaccination coverage was estimated at 52% (47%-56%) for MSP, 53% (47%-60%) for DDV?+?ORV, and 65% (61%-69%) for MSP?+?CVR (differences with MSP and DDV?+?ORV significant at p?<?0.01). Total dog vaccination coverage was 33% (95% CI: 26%-43%) for MSP, 49% (95% CI: 40%-61%) for MSP?+?CVR and 78% (77%-80%) for DDV?+?ORV (differences significant at p?<?0.001). Overall, the least expensive campaign was MSP, with an estimated cost of about 2039perday(2039 per day (4078 total), and the most expensive was DDV?+?ORV with a cost of 3246perday(3246 per day (6492 total). Despite the relative high cost of an ORV bait, combining DDV and ORV was the most cost-effective strategy in our study (1.97pervaccinateddog),largelyduetoincreasedefficiencyofthevaccinatorstotargetlessaccessibledogs.Costspervaccinateddogwere1.97 per vaccinated dog), largely due to increased efficiency of the vaccinators to target less accessible dogs. Costs per vaccinated dog were 2.20 for MSP and $2.28 for MSP?+?CVR. We hope the results from this study will support the design and implementation of effective dog vaccination campaigns to achieve the goal of eliminating dog-mediated human rabies deaths by 2030
    • …
    corecore