2,323 research outputs found

    Quantum Electrodynamics vacuum polarization solver

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    The self-consistent modeling of vacuum polarization due to virtual electron-positron fluctuations is of relevance for many near term experiments associated with high intensity radiation sources and represents a milestone in describing scenarios of extreme energy density. We present a generalized finite-difference time-domain solver that can incorporate the modifications to Maxwell's equations due to vacuum polarization. Our multidimensional solver reproduced in one dimensional configurations the results for which an analytic treatment is possible, yielding vacuum harmonic generation and birefringence. The solver has also been tested for two-dimensional scenarios where finite laser beam spot sizes must be taken into account. We employ this solver to explore different types of counter-propagating configurations that can be relevant for future planned experiments aiming to detect quantum vacuum dynamics at ultra-high electromagnetic field intensities

    Intravitreal anti-VEGF therapy for choroidal neovascularisation secondary to pathological myopia: 4-year outcome

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    OBJECTIVE: To report the visual outcome after 4-year follow-up in a series of highly myopic eyes with choroidal neovascularisation (CNV) treated with antivascular endothelial growth factor (anti-VEGF) drugs. METHODS: A retrospective, non-randomised, multicentre, consecutive, interventional case series study was performed. 92 highly myopic eyes with subfoveal CNV were treated with intravitreal injection (IVI) of anti-VEGF. The initial protocol (1 vs 3 injections) was dictated by surgeons' preferences and followed by an as-needed monthly regime. Best-corrected visual acuity (BCVA) was evaluated at baseline and then monthly. The primary aim was to analyse BCVA changes. The effect of age, spherical equivalent (SE) and treating drug were evaluated as secondary objectives. RESULTS: The mean age of the patients was 57 years (SD 14, range 30-93). The mean number of letters read was 46.1 (SD 16.8, range 5-70) at baseline, 55.5 (SD 18.6, range 10-85) at 12 months, 50.1 (SD 20.1, range 5-82) at 24 months, 54.2 (SD 21.9, range 2-85) at 36 months and 53.1 (SD 22.5, range 1-83) at 48 months (p=0.000, initial vs 12, 24 and 36 months; p=0.01 initial vs 48 months; Student t test for paired data). The mean total number of IVI was 4.9 (SD 5.4, range 1-29). SE and treating drug had no influence on the final visual outcome and number of injections required. CONCLUSIONS: Intravitreal bevacizumab and ranibizumab are effective therapies and show similar clinical effects in highly myopic CNV. Visual acuity gain is maintained at 4-year follow-up

    Cultivo agroecológico do cafeeiro: produtividade de cultivares em sistema solteiro e consorciado com bananeira.

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    bitstream/item/68473/1/039-Cultivo-agroecologico-do-cafeeiro.pdfPublicado também no Cadernos de Agroecologia, v. 7, n. 2, 2012

    Increased IgE serum levels are unrelated to allergic and parasitic diseases in patients with juvenile systemic lupus erythematosus

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    OBJECTIVE: The aim of this study was to assess the IgE serum levels in juvenile systemic lupus erythematosus patients and to evaluate possible associations with clinical and laboratory features, disease activity and tissue damage. METHODS: The IgE serum concentrations in 69 consecutive juvenile systemic lupus erythematosus patients were determined by nephelometry. IgG, IgM and IgA concentrations were measured by immunoturbidimetry. All patients were negative for intestinal parasites. Statistical analysis methods included the Mann-Whitney, chi-square and Fisher's exact tests, as well as the Spearman rank correlation coefficient. RESULTS: Increased IgE concentrations above 100 IU/mL were observed in 31/69 (45%) juvenile systemic lupus erythematosus patients. The mean IgE concentration was 442.0 ± 163.4 IU/ml (range 3.5-9936.0 IU/ml). Fifteen of the 69 patients had atopic disease, nine patients had severe sepsis and 56 patients presented with nephritis. The mean IgE level in 54 juvenile systemic lupus erythematosus patients without atopic manifestations was 271.6 ± 699.5 IU/ml, and only nine of the 31 (29%) patients with high IgE levels had atopic disease. The IgE levels did not statistically differ with respect to the presence of atopic disease, severe sepsis, nephritis, disease activity, or tissue damage. Interestingly, IgE concentrations were inversely correlated with C4 levels (r = -0.25, p = 0.03) and with the SLICC/ACR-DI score (r = -0.34, p = 0.005). The IgE concentration was also found to be directly correlated with IgA levels (r = 0.52, p = 0.03). CONCLUSIONS: The present study demonstrated for the first time that juvenile systemic lupus erythematosus patients have increased IgE serum levels. This increase in IgE levels was not related to allergic or parasitic diseases. Our results are in line with the hypothesis that high IgE levels can be considered a marker of immune dysregulation

    Quantum electrodynamics vacuum polarization solver

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    The self-consistent modeling of vacuum polarization due to virtual electron-positron fluctuations is of relevance for many near term experiments associated with high intensity radiation sources and represents a milestone in describing scenarios of extreme energy density. We present a generalized finite-difference time-domain solver that can incorporate the modifications to Maxwell’s equations due to vacuum polarization. Our multidimensional solver reproduced in one-dimensional configurations the results for which an analytic treatment is possible, yielding vacuum harmonic generation and birefringence. The solver has also been tested for two-dimensional scenarios where finite laser beam spot sizes must be taken into account. We employ this solver to explore different types of laser configurations that can be relevant for future planned experiments aiming to detect quantum vacuum dynamics at ultra-high electromagnetic field intensities.info:eu-repo/semantics/publishedVersio
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