87 research outputs found

    Fast soil solution nutrient and water dynamics in top- and subsoil.

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    Study for find out the short-term dynamics of applied fertilizer. In a soil pit a data logger system connected to tensiometers and TDR was installed up to a depth of 3.5m under pueraria in an agroforestry system (cupuacu, peach palm, Brazil nut, urucum). After a rainfall event, the soil water suction at 0.1m depth increased immediately, and fast responses were seen even up to a depth of 0.9m. This result may indicate that nutrients may be leached very fast even in these soil with high clay contents. The N concentrations in the soil solution relevantly increased at 0.1m depth during the same time period, as shown for peach palm. First, the ammonium concentrations increased, but nitrate contents followed rapidly indicanting a fast nitrification in the studied soils.bitstream/item/210595/1/Water-and-nutrient-p54.pd

    Influence of the Microstructural Texture of Cast Superalloys on their High-Temperature Oxidation Behaviour

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    International audienceThe high-temperature oxidation behaviours of Ni base and Co base cast superalloys were studied to determine the effect of different grain sizes and different surface dendritic orientations. These microstructural characteristics were obtained by varying solidification rate and cutting orientation with regard to the external surface. Thermogravimetry tests were run at 1000 and 1100°C and parabolic oxidation constants were considered. It appears that oxidation is faster for fine microstructures than for coarser ones for Ni or Co alloys including tungsten in their chemical composition, while it is the contrary when W is not present. When the sample surface is mainly parallel to the dendritic network, the oxidation rate is greater than for a surface perpendicular to dendrites, for the studied Ni alloy. The same phenomenon is observed for the studied Co base alloy at 1100°C but the order is inverted at 1000°C. These different behaviours can be explained by the grain boundary densities and orientations obtained on surface, since they can influence the diffusion of species involved in the oxidation phenomena. It is also possible that the characteristics of the chromia scale, such as grain size and general quality, depend on the microstructural texture of the alloy

    The Effect of Financial Incentives on Patient Decisions to Undergo Low‐value Head Computed Tomography Scans

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    BackgroundExcessive diagnostic testing and defensive medicine contribute to billions of dollars in avoidable costs in the United States annually. Our objective was to determine the influence of financial incentives, accompanied with information regarding test risk and benefit, on patient preference for diagnostic testing.MethodsWe conducted a cross‐sectional survey of patients at the University of Michigan emergency department (ED). Each participant was presented with a hypothetical scenario involving an ED visit following minor traumatic brain injury. Participants were given information regarding potential benefit (detecting brain hemorrhage) and risk (developing cancer) of head computed tomography scan, as well as an incentive of 0or0 or 100 to forego testing. We used 0.1 and 1% for test benefit and risk, and values for risk, benefit, and financial incentive varied across participants. Our primary outcome was patient preference to undergo testing. We also collected demographic and numeracy information. We then used logistic regression to estimate odds ratios (ORs), which were adjusted for multiple potential confounders. Our sample size was designed to find at least 300 events (preference for testing) to allow for inclusion of up to 30 covariates in fully adjusted models. We had 85% to 90% power to detect a 10% absolute difference in testing rate across groups, assuming a 95% significance level.ResultsWe surveyed 913 patients. Increasing test benefit from 0.1% to 1% significantly increased test acceptance (adjusted OR [AOR] = 1.6, 95% confidence interval [CI] = 1.2 to 2.1) and increasing test risk from 0.1% to 1% significantly decreased test acceptance (AOR = 0.70, 95% CI = 0.52 to 0.93). Finally, a $100 incentive to forego low‐value testing significantly reduced test acceptance (AOR = 0.6; 95% CI = 0.4 to 0.8).ConclusionsProviding financial incentives to forego testing significantly decreased patient preference for testing, even when accounting for test benefit and risk. This work is preliminary and hypothetical and requires confirmation in larger patient cohorts facing these actual decisions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151851/1/acem13823_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151851/2/acem13823-sup-0001-DataSupplementS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151851/3/acem13823.pd

    Fate of applied N fertilizer in mixed cropping systems in the central Amazon.

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    Aim of the study was to investigate the nitrogen dynamics and the fate of applied nitrogen fertilizer in the soil-plant system of a mixed cropping system consisting of peach palm, cupuacu, urucu, and Brazil nut, in the Manaus-AM (Brasil). According the results, annato, cupuacu and peach palm seemed to take up more than 90% of th incorporated nitrogen fertilizer under their own canopy. However, Brazil nut took up more than 70% of the fertilized nitrogen from the fertilized areas under the canopies of the neighboring trees (peach palm: 40%, annato: 25%, cupuacu: 8%) two weeks of the fertilizer application. At the end of the rainy season, Brazil nut even took up more than 80% from underneath neighboring trees crops (peach palm: 42%, annato: 36%, cupuacu: 6%). Furthemrmore, peach palm and Brazil nut were better able than the other two trees in reducing nutrient leaching due to their deep root system

    Pan-Pathway Based Interaction Profiling of FDA-Approved Nucleoside and Nucleobase Analogs with Enzymes of the Human Nucleotide Metabolism

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    To identify interactions a nucleoside analog library (NAL) consisting of 45 FDA-approved nucleoside analogs was screened against 23 enzymes of the human nucleotide metabolism using a thermal shift assay. The method was validated with deoxycytidine kinase; eight interactions known from the literature were detected and five additional interactions were revealed after the addition of ATP, the second substrate. The NAL screening gave relatively few significant hits, supporting a low rate of “off target effects.” However, unexpected ligands were identified for two catabolic enzymes guanine deaminase (GDA) and uridine phosphorylase 1 (UPP1). An acyclic guanosine prodrug analog, valaciclovir, was shown to stabilize GDA to the same degree as the natural substrate, guanine, with a ΔTagg around 7°C. Aciclovir, penciclovir, ganciclovir, thioguanine and mercaptopurine were also identified as ligands for GDA. The crystal structure of GDA with valaciclovir bound in the active site was determined, revealing the binding of the long unbranched chain of valaciclovir in the active site of the enzyme. Several ligands were identified for UPP1: vidarabine, an antiviral nucleoside analog, as well as trifluridine, idoxuridine, floxuridine, zidovudine, telbivudine, fluorouracil and thioguanine caused concentration-dependent stabilization of UPP1. A kinetic study of UPP1 with vidarabine revealed that vidarabine was a mixed-type competitive inhibitor with the natural substrate uridine. The unexpected ligands identified for UPP1 and GDA imply further metabolic consequences for these nucleoside analogs, which could also serve as a starting point for future drug design

    Nutrient leaching in mixed tree cropping systems.

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    Study on the leaching losses of applied 15N tagged fertilizer during one rainy season, in Manaus-AM (Brasil).bitstream/item/209951/1/Water-and-nutrient-fluxes-p41.pd

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    Soil nutrient leaching in mixed tree cropping systems in the central Amazon.

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    Studies on the leaching losses of applied 15N tagged fertilizer during one rainy season, in the central Amazonia (Manaus-AM, Brasil). TDR, tensiometers and suction cups were installed under cupuacu, pupunha (peach palm), castanha-do-Para (Brazil nut) and urucu (annatto) in a mult-strata agroforestry system. The trees affected leaching losses of applied N to a different extend, and pupunha and urucu were better able to do so than the other investigated species. However, losses of applied fertilizer N can not entirely be prevented considering the extremely rapid soil water percolation under the studied humid tropical conditions and the highly permeable soil
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