6,800 research outputs found

    Metodologia de amostragem para avaliação da qualidade das pastagens nativas consumidas por bovinos no Pantanal.

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    Interação bovino x planta do Pantanal; Estratégia de forrageamento; Comportamento de pastejo; Teste de metodologia; Descrição da metodologia proposta para a avaliação do valor nutritivo e composição botânica das pastagens nativas consumidas por bovinos no Pantanal.bitstream/item/37729/1/DOC31.pd

    Associations between clinical features and therapy with macrophage subpopulations and T cells in inflammatory lesions in the aorta from patients with Takayasu arteritis

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    Takayasu arteritis (TAK) is a large-vessel granulomatous vasculitis; the inflammatory infiltration in arteries comprises macrophages, multi-nucleated giant cells, CD4+ and CD8+ T cells, γδ T cells, natural killer (NK) cells and neutrophils. However, it is unknown which subtype of macrophages predominates. This study aims to evaluate macrophages subpopulations in the aorta in TAK. Immunohistochemistry was performed in the aorta from TAK patients (n = 22), patients with atherosclerotic disease (n = 9) and heart transplant donors (n = 8) using the markers CD68, CD86, CD206, CD3, CD20 and CD56. Active disease was observed in 54·5% of patients and active histological lesions were found in 40·9%. TAK patients presented atherosclerotic lesions in 27·3% of cases. The frequency of macrophages, M1 macrophages, T, B and NK cells was higher in the aorta from TAK and atherosclerotic patients compared to heart transplant donors. In TAK, macrophages and T cells were the most abundant cells in the aorta, and the expression of CD206 was higher than CD86 (P = 0·0007). No associations were found between the expression of cell markers and active disease or with atherosclerotic lesions. In TAK patients, histological disease activity led to higher T cell counts than chronic fibrotic lesions (P = 0.030), whereas prednisone use was associated with lower T cell counts (P = 0·035). In conclusion, M1 macrophages were more frequent in TAK and atherosclerotic patients compared to heart transplant donors, while M2 macrophages dominated M1 macrophages in TAK. T cells were associated with histological disease activity and with prednisone use in TAK

    Postpartum changes in plasma viral load and CD4 percentage among HIV-infected women from Latin American and Caribbean countries: the NISDI Perinatal Study

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    The goal of this study was to evaluate changes in plasma human immunodeficiency virus (HIV) RNA concentration [viral load (VL)] and CD4+ percentage (CD4%) during 6-12 weeks postpartum (PP) among HIV-infected women and to assess differences according to the reason for receipt of antiretrovirals (ARVs) during pregnancy [prophylaxis (PR) vs. treatment (TR)]. Data from a prospective cohort of HIV-infected pregnant women (National Institute of Child Health and Human Development International Site Development Initiative Perinatal Study) were analyzed. Women experiencing their first pregnancy who received ARVs for PR (started during pregnancy, stopped PP) or for TR (initiated prior to pregnancy and/or continued PP) were included and were followed PP. Increases in plasma VL (> 0.5 log10) and decreases in CD4% (> 20% relative decrease in CD4%) between hospital discharge (HD) and PP were assessed. Of the 1,229 women enrolled, 1,119 met the inclusion criteria (PR: 601; TR: 518). At enrollment, 87% were asymptomatic. The median CD4% values were: HD [34% (PR); 25% (TR)] and PP [29% (PR); 24% (TR)]. The VL increases were 60% (PR) and 19% (TR) (p < 0.0001). The CD4% decreases were 36% (PR) and 18% (TR) (p < 0.0001). Women receiving PR were more likely to exhibit an increase in VL [adjusted odds ratio (AOR) 7.7 (95% CI: 5.5-10.9) and a CD4% decrease (AOR 2.3; 95% CI: 1.6-3.2). Women receiving PR are more likely to have VL increases and CD4% decreases compared to those receiving TR. The clinical implications of these VL and CD4% changes remain to be explored.Universidade Federal de Minas Gerais Faculdade de MedicinaWestatUniversidad Nacional Mayor de San MarcosHospital FeminaHospital ConceiçãoUniversidade Federal de São Paulo (UNIFESP)Hospital dos Servidores do EstadoNational Institute of Health Human Development Department of Health and Human ServicesUNIFESPSciEL

    Forward Global Photometric Calibration of the Dark Energy Survey

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    Many scientific goals for the Dark Energy Survey (DES) require calibration of optical/NIR broadband b=grizYb = grizY photometry that is stable in time and uniform over the celestial sky to one percent or better. It is also necessary to limit to similar accuracy systematic uncertainty in the calibrated broadband magnitudes due to uncertainty in the spectrum of the source. Here we present a "Forward Global Calibration Method (FGCM)" for photometric calibration of the DES, and we present results of its application to the first three years of the survey (Y3A1). The FGCM combines data taken with auxiliary instrumentation at the observatory with data from the broad-band survey imaging itself and models of the instrument and atmosphere to estimate the spatial- and time-dependence of the passbands of individual DES survey exposures. "Standard" passbands are chosen that are typical of the passbands encountered during the survey. The passband of any individual observation is combined with an estimate of the source spectral shape to yield a magnitude mbstdm_b^{\mathrm{std}} in the standard system. This "chromatic correction" to the standard system is necessary to achieve sub-percent calibrations. The FGCM achieves reproducible and stable photometric calibration of standard magnitudes mbstdm_b^{\mathrm{std}} of stellar sources over the multi-year Y3A1 data sample with residual random calibration errors of σ=56mmag\sigma=5-6\,\mathrm{mmag} per exposure. The accuracy of the calibration is uniform across the 5000deg25000\,\mathrm{deg}^2 DES footprint to within σ=7mmag\sigma=7\,\mathrm{mmag}. The systematic uncertainties of magnitudes in the standard system due to the spectra of sources are less than 5mmag5\,\mathrm{mmag} for main sequence stars with 0.5<gi<3.00.5<g-i<3.0.Comment: 25 pages, submitted to A

    Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels

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    Simultaneous analysis of economic and environmental performance of horticultural crop production requires qualified assumptions on the effect of management options, and particularly of nitrogen (N) fertilisation, on the net returns of the farm. Dynamic soil-plant-environment simulation models for agro-ecosystems are frequently applied to predict crop yield, generally as dry matter per area, and the environmental impact of production. Economic analysis requires conversion of yields to fresh marketable weight, which is not easy to calculate for vegetables, since different species have different properties and special market requirements. Furthermore, the marketable part of many vegetables is dependent on N availability during growth, which may lead to complete crop failure under sub-optimal N supply in tightly calculated N fertiliser regimes or low-input systems. In this paper we present two methods for converting simulated total dry matter to marketable fresh matter yield for various vegetables and European growth conditions, taking into consideration the effect of N supply: (i) a regression based function for vegetables sold as bulk or bunching ware and (ii) a population approach for piecewise sold row crops. For both methods, to be used in the context of a dynamic simulation model, parameter values were compiled from a literature survey. Implemented in such a model, both algorithms were tested against experimental field data, yielding an Index of Agreement of 0.80 for the regression strategy and 0.90 for the population strategy. Furthermore, the population strategy was capable of reflecting rather well the effect of crop spacing on yield and the effect of N supply on product grading

    Astrometric calibration and performance of the Dark Energy Camera

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    We characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500~Mpix, 3 deg^2 science field of view, and across 4 years of operation. This is done using internal comparisons of ~4x10^7 measurements of high-S/N stellar images obtained in repeat visits to fields of moderate stellar density, with the telescope dithered to move the sources around the array. An empirical astrometric model includes terms for: optical distortions; stray electric fields in the CCD detectors; chromatic terms in the instrumental and atmospheric optics; shifts in CCD relative positions of up to ~10 um when the DECam temperature cycles; and low-order distortions to each exposure from changes in atmospheric refraction and telescope alignment. Errors in this astrometric model are dominated by stochastic variations with typical amplitudes of 10-30 mas (in a 30 s exposure) and 5-10 arcmin coherence length, plausibly attributed to Kolmogorov-spectrum atmospheric turbulence. The size of these atmospheric distortions is not closely related to the seeing. Given an astrometric reference catalog at density ~0.7 arcmin^{-2}, e.g. from Gaia, the typical atmospheric distortions can be interpolated to 7 mas RMS accuracy (for 30 s exposures) with 1 arcmin coherence length for residual errors. Remaining detectable error contributors are 2-4 mas RMS from unmodelled stray electric fields in the devices, and another 2-4 mas RMS from focal plane shifts between camera thermal cycles. Thus the astrometric solution for a single DECam exposure is accurate to 3-6 mas (0.02 pixels, or 300 nm) on the focal plane, plus the stochastic atmospheric distortion.Comment: Submitted to PAS

    Photometric redshifts and clustering of emission line galaxies selected jointly by DES and eBOSS

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    We present the results of the first test plates of the extended Baryon Oscillation Spectroscopic Survey. This paper focuses on the emission line galaxies (ELG) population targetted from the Dark Energy Survey (DES) photometry. We analyse the success rate, efficiency, redshift distribution, and clustering properties of the targets. From the 9000 spectroscopic redshifts targetted, 4600 have been selected from the DES photometry. The total success rate for redshifts between 0.6 and 1.2 is 71\% and 68\% respectively for a bright and faint, on average more distant, samples including redshifts measured from a single strong emission line. We find a mean redshift of 0.8 and 0.87, with 15 and 13\% of unknown redshifts respectively for the bright and faint samples. In the redshift range 0.6<z<1.2, for the most secure spectroscopic redshifts, the mean redshift for the bright and faint sample is 0.85 and 0.9 respectively. Star contamination is lower than 2\%. We measure a galaxy bias averaged on scales of 1 and 10~Mpc/h of 1.72 \pm 0.1 for the bright sample and of 1.78 \pm 0.12 for the faint sample. The error on the galaxy bias have been obtained propagating the errors in the correlation function to the fitted parameters. This redshift evolution for the galaxy bias is in agreement with theoretical expectations for a galaxy population with MB-5\log h < -21.0. We note that biasing is derived from the galaxy clustering relative to a model for the mass fluctuations. We investigate the quality of the DES photometric redshifts and find that the outlier fraction can be reduced using a comparison between template fitting and neural network, or using a random forest algorithm
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