5,966 research outputs found

    On-line mixed hemodiafiltration with a feedback for ultrafiltration control: Effect on middle-molecule removal

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    On-line mixed hemodiafiltration with a feedback for ultrafiltration control: Effect on middle-molecule removal.BackgroundIncreased middle-molecular uremic toxin removal seems to favorably influence survival in dialysis patients. The aim of this study was to verify if, in on-line mixed hemodiafiltration, solute removal by convection may be enhanced by forcing the ultrafiltration rate (QUF) and optimizing the infusion technique in order to achieve the highest possible filtration fraction (FF).MethodsRemoval of β2-microglobulin (β2-m), urea, creatinine, and phosphate were compared in 20 patients randomly submitted to one dialysis session (A), one postdilution hemodiafiltration session (B), and three sessions of mixed hemodiafiltration (C, D, and E) at different infusion rates (QS). In mixed hemodiafiltration, a newly developed feedback system automatically maintained the transmembrane pressure (TMP) within its highest range of safety (250 to 300mm Hg) at constant QUF, while ensuring the maximum FF by splitting infusion between pre- and postdilution.ResultsA mean QS of 134 ± 20mL/min (mean FF = 0.65) was attained in post-HDF, and up to 307 ± 41mL/min (mean FF = 0.69) in mixed hemodiafiltration. The mean dialysate clearances (KDQ) for all tested solutes and urea eKt/V were significantly higher in all hemodiafiltration sessions than in dialysis. Only in the case of urea did the infusion mode have no significant effect. KDQ for β2-m was maximal in session D and significantly higher than in session B (90.2 ± 11mL/min vs. 77.5 ± 11mL/min; P = 0.02). KDQ for β2-m significantly correlated with QS and the plasma water flow rate (QPW). The highest KDQ for β2-m was found at values of QS∼ QPW. Beyond this value KDQ decreased.ConclusionThe mixed infusion mode in hemodiafiltration, controlled by the TMP-ultrafiltration feedback, seems to improve the efficiency of hemodiafiltration by fully exploiting the convective mechanism of solute removal. The feedback automatically adjusted the infusion rate and site to the maximum FF taking into account flow conditions, internal pressures, and hydraulic permeability of the dialyzer and their complex interactions

    Caracterização matemática da morte de células de inseto (IPLB-Sf21) em infecção suspensa com o baculovírus Anticarsia gemmatalis MNPV.

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    Asian soybean rust: modeling the impact on soybean grain yield in the Triângulo Mineiro / Alto Paranaíba Region, Minas Gerais, Brazil.

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    Understanding the impact of Asian soybean rust on soybean yield is of great importance in the crop simulation model for this crop become it is possible to predict yield using different sowing dates and growth conditions. The goal of this study were to evaluate the performance of two soybean cultivars in Triângulo Mineiro/Alto Paranaíba, MG, Brazil and the effects of soybean rust on the yield of these cultivars using the CSM-CROPGRO Soybean model. Two soybean cultivars NK 7074 (early) and UFUS-Impacta (medium late), which differ in their development cycles, were growing in Uberaba city during the 2009/2010 growing season. The validation for cultivar UFUS-Impacta was conducted comparing the measured and simulated yield data considering three different sowing dates in the Uberlândia city during the 2002/2003 growing season. Daily meteorological data obtained from six meteorological stations of the National Institute of Meteorology (INMET ). To determine the performance of the soybean cultivars and the effect of soybean rust on yield, three different scenarios were used: no occurrence of rust (NOR) and occurrence of rust with inoculum concentrations of U5.000 and U10.000 urediniospores/mL. For all environments studied, the early cultivar had the best performance than the medium late cultivar. Soybean rust had the most effect on yield for the U10.000 scenario than for the U5.000 scenario. The best soybean performance occurred for Araxá and Uberaba cities. The South-Southeast area of the Triângulo Mineiro/Alto Paranaíba region was the most sensitive to the effect of rust on yield compared to the North region

    A High Statistics Measurement of the Lambdac+ Lifetime

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    A high statistics measurement of the Lambdac+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat.) +/- 2.5 (syst.) fs from 8034 +/- 122 Lambdac -> pKpi decays represents a significant improvement over the present world average.Comment: Submitted to Physical Review Letter

    A Measurement of the Ds+ Lifetime

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    A high statistics measurement of the Ds+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis of the two decay modes, Ds+ -> phi(1020)pi+ and Ds+ -> \bar{K}*(892)0K+, used for the measurement. The measured lifetime is 507.4 +/- 5.5 (stat.) +/- 5.1 (syst.) fs using 8961 +/- 105 Ds+ -> phi(1020)pi+ and 4680 +/- 90 Ds+ -> \bar{K}*(892)0K+ decays. This is a significant improvement over the present world average.Comment: 5 pages, 3 figures, 2 tables, submitted to PR

    Spatio-temporal variation in the wintering associations of an alpine bird

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    Many animals make behavioural changes to cope with winter conditions, being gregariousness a common strategy. Several factors have been invoked to explain why gregariousness may evolve during winter, with individuals coming together and separating as they trade off the different costs and benefits of living in groups. These trade-offs may, however, change over space and time as a response to varying environmental conditions. Despite its importance, little is known about the factors triggering gregarious behaviour during winter and its change in response to variation in weather conditions is poorly documented. Here, we aimed at quantifying large-scale patterns in wintering associations over 23 years of the white-winged snowfinch Montifringilla nivalis nivalis. We found that individuals gather in larger groups at sites with harsh wintering conditions. Individuals at colder sites reunite later and separate earlier in the season than at warmer sites. However, the magnitude and phenology of wintering associations are ruled by changes in weather conditions. When the temperature increased or the levels of precipitation decreased, group size substantially decreased, and individuals stayed united in groups for a shorter time. These results shed light on factors driving gregariousness and points to shifting winter climate as an important factor influencing this behaviour

    Search for CP Violation in the decays D+ -> K_S pi+ and D+ -> K_S K+

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    A high statistics sample of photo-produced charm from the FOCUS(E831) experiment at Fermilab has been used to search for direct CP violation in the decays D+->K_S pi+ and D+ -> K_S K+. We have measured the following asymmetry parameters relative to D+->K-pi+pi+: A_CP(K_S pi+) = (-1.6 +/- 1.5 +/- 0.9)%, A_CP(K_S K+) = (+6.9 +/- 6.0 +/- 1.5)% and A_CP(K_S K+) = (+7.1 +/- 6.1 +/- 1.2)% relative to D+->K_S pi+. The first errors quoted are statistical and the second are systematic. We also measure the relative branching ratios: \Gamma(D+->\bar{K0}pi+)/\Gamma(D+->K-pi+pi+) = (30.60 +/- 0.46 +/- 0.32)%, \Gamma(D+->\bar{K0}K+)/\Gamma(D+->K-pi+pi+) = (6.04 +/- 0.35 +/- 0.30)% and \Gamma(D+->\bar{K0}K+)/\Gamma(D+->\bar{K0}pi+) = (19.96 +/- 1.19 +/- 0.96)%.Comment: 4 pages, 3 figure
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