947 resultados para 13200-036
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Algae bloom is one of the major consequences of the eutrophication of aquatic systems, including algae capable of producing toxic substances. Among these are several species of cyanobacteria, also known as blue-green algae, that have the capacity to adapt themselves to changes in the water column. Thus, the horizontal distribution of cyanobacteria harmful algae blooms (CHABs) is essential, not only to the environment, but also for public health. The use of remote sensing techniques for mapping CHABs has been explored by means of bio-optical modeling of phycocyanin (PC), a unique inland waters cyanobacteria pigment. However, due to the small number of sensors with a spectral band of the PC absorption feature, it is difficult to develop semi-analytical models. This study evaluated the use of an empirical model to identify CHABs using TM and ETM+ sensors aboard Landsat 5 and 7 satellites. Five images were acquired for applying the model. Besides the images, data was also collected in the Guarapiranga Reservoir, in São Paulo Metropolitan Region, regarding the cyanobacteria cell count (cells/mL), which was used as an indicator of CHABs biomass. When model values were analyzed excluding calibration factors for temperate lakes, they showed a medium correlation (R²=0.81, p=0.036), while when the factors were included the model showed a high correlation (R²=0.96, p=0.003) to the cyanobacteria cell count. The empirical model analyzed proved useful as an important tool for policy makers, since it provided information regarding the horizontal distribution of CHABs which could not be acquired from traditional monitoring techniques.
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Sodium titanate was synthesized by the sol-gel method and characterized using X-ray diffraction, thermogravimetry-mass spectrometry, atomic absorption spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis and nitrogen physisorption. The non-calcined material was active as a catalyst in transesterification reactions and showed high stability. An appreciable loss of activity on the fourth reuse was accompanied by the appearance of a new species of oxygen and segregated sodium, identified by X-ray photoelectron spectroscopy (XPS). The XPS spectrum showed that the basic nature of the framework oxygen was inferior to the original basicity, which explained the decline in catalytic activity. (C) 2013 Elsevier Ltd. All rights reserved.
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This paper presents numerical modeling of a turbulent natural gas flow through a non-premixed industrial burner of a slab reheating furnace. The furnace is equipped with diffusion side swirl burners capable of utilizing natural gas or coke oven gas alternatively through the same nozzles. The study is focused on one of the burners of the preheating zone. Computational Fluid Dynamics simulation has been used to predict the burner orifice turbulent flow. Flow rate and pressure at burner upstream were validated by experimental measurements. The outcomes of the numerical modeling are analyzed for the different turbulence models in terms of pressure drop, velocity profiles, and orifice discharge coefficient. The standard, RNG, and Realizable k-epsilon models and Reynolds Stress Model (RSM) have been used. The main purpose of the numerical investigation is to determine the turbulence model that more consistently reproduces the experimental results of the flow through an industrial non-premixed burner orifice. The comparisons between simulations indicate that all the models tested satisfactorily and represent the experimental conditions. However, the Realizable k-epsilon model seems to be the most appropriate turbulence model, since it provides results that are quite similar to the RSM and RNG k-epsilon models, requiring only slightly more computational power than the standard k-epsilon model. (C) 2014 Elsevier Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A new selective sensor based on molecularly imprinted polymers (MIPs) was developed for the determination of hexazinone (HXZ) in environmental samples. MIPs were synthesized using a non-covalent approach, and selection of the monomers employed in the polymerization reaction was carried out by molecular modeling. Three functional monomers with high (2-vinylpyridine (MP17)) and intermediate (methacrylic acid (MP12) and acrylamide (MP5)) energies of binding to the template (HXZ) were selected for preparation of the MIPs, in order to conduct comparative studies and validate the theoretical data. For sensor construction, carbon pastes were modified with each MIP or NIP (non-imprinted polymer), and HXZ determination was performed using differential pulse adsorptive cathodic stripping voltammetry (DPAdCSV). All parameters affecting the sensor response were optimized. In HCl at pH 2.5, the sensor prepared with MP17 (5% w/w in the paste) showed a dynamic linear range between 1.9 × 10−11 and 1.1 × 10−10 mol L−1, and a detection limit of 2.6 × 10−12 mol L−1, under the following conditions: accumulation time of 200 s at a potential of −0.5V, scan rate of 50 mVs−1, pulse amplitude of 60 mV, and pulse width of 50 ms. The sensor was selective in the presence of other similar compounds, and was successfully applied to the analysis of HXZ in river water samples.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Different environmental disasters registered around the world and their consequences to nature and to the biodiversity, including the human beings, lead us to deal with nature’s mysteries and with our limits In controlling technological apparatus that make us proud enough to think that we can control nature’s processes. These kinds of experiences, considered as a real “being-event”, make us experiment processes of disillusion related to the possibilities of science and technology. Considering this frame and the historical human experiences, one fundamental question is related to our position, our professional and ethical commitments and our responsibilities facing this reality. How can we deal with these facts that are continuously announcing the limits of nature, of science, technologies and our self-limits? As researchers involved with environmental education, it seems plausible for us to ask about the ethical commitments related to our “acts” of investigation. So, considering different and stimulating possibilities opened by intellectual and philosophers who are adding significant contributions to these debates, my proposal for this essay is to invite environmental education researchers to carry on a dialog involving these questions with some perspectives proposed specially by Bakhtin (1895 – 1975) and some other authors affiliated or not to his approach. This seems to be an opportunity which allows us to realize that our commitments as environmental education researchers would be identified with our commitments with life
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Abstract Introduction: Indications for induction therapy is not consensual in living donors. Objective: The objective of this study was compare no induction with thymoglobulin and basiliximab induction in the incidence of acute rejection in kidney transplantation with living donor. Methods: We select all cases of renal transplantation with living donor performed in Hospital das Clínicas de Botucatu da UNESP during the period of January 2010 to December 2013. The group was divided by the type of medication used for induction. Results: A total of 90 patients were evaluated. There were no differences in baseline characteristics of age and underlying disease. The rate of biopsy-proven acute rejection was higher in the group without induction (42.9%) compared to basiliximab group (20%) and Thymoglobulin (16.7%), p = 0.04. The rejection by compatibility shows that the identical had the lower rejection rate (10%). The haploidentical group without induction had the highest rejection rates (53.3%). In all distinct group the rejection rates were similar with basiliximab or Thymoglobulin, p = NS. The use of induction therapy was associated independently with a lower risk of rejection (OR = 0.32 CI: 0.11 to 0.93, p = 0.036). There were no differences in renal function at 6 months and patient survival and graft in the three groups. Discussion: The haploidentical patients without induction were those with higher rates of acute rejection. The group of patients induced with Thymoglobulin had a higher immunological risk, however showed low rates of rejection. Conclusion: The use of induction therapy resulted in lower rates of rejection in transplantation with living donor.
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Objective Despite rising global obesity rates, the impact of obesity on gestational trophoblastic neoplasia (GTN) remains uninvestigated. This study aimed at investigating whether overweight/obesity relates to response to chemotherapy in low-risk GTN patients.Methods This nonconcurrent cohort study included 300 patients with International Federation of Gynecology and Obstetrics-defined postmolar low-risk GTN treated with a single-agent chemotherapymethotrexate or actinomycin-D (actD)between 1973 and 2012 at the New England Trophoblastic Disease Center. Chemotherapy dosing was based on actual body weight regardless of obesity status, except for 5-day courses or pulse regimens of actD. Patients were classified as overweight/obese (body mass index [BMI] 25 kg/m(2)) or non-overweight/obese (BMI <25 kg/m(2)). Information on patient characteristics and response to chemotherapy (need for second-line chemotherapy, reason for changing to an alternative chemotherapy, number of cycles, need for combination chemotherapy, and time to human chorionic gonadotropin remission) was obtained.Results Of 300 low-risk GTN patients, 81 (27%) were overweight/obese. Overweight/obese patients were older than the non-overweight/obese patients (median age: 30 vs 28 years, P = 0.004). First-line therapy using actD was more frequent in overweight/obese patients (6.2% vs 1.4%, P = 0.036). Resistance and toxicity were similar between groups. No significant difference in the number of chemotherapy cycles needed for remission or time required to achieve remission was found between groups.Conclusions No association between overweight/obesity and low-risk GTN outcomes was found. Current chemotherapy dosing using BMI seems to be appropriate for overweight/obese patients with low-risk GTN.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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A series of four different powders ceria doped Ce1-xErxO2-delta (0.05 <= x <= 0.20) were synthesized by applying self-propagating reaction at room temperature (SPRT method). SPRT procedure is based on the self-propagating room temperature reaction between metal nitrates and sodium hydroxide, wherein the reaction is spontaneous and terminates extremely fast. The method is known to assure very precise stoichiometry of the final product in comparison with a tailored composition. XRPD, Raman spectroscopy, TEM and BET measurements were used to characterize the nanopowders at room temperature. It was shown that all obtained powders were single phase solid solutions with a fluorite-type crystal structure and all powder particles have nanometric size (about 3-4 nm). Densification was performed at 1550 degrees C, in an air atmosphere for 2 h. XRPD, SEM and complex impedance method measurements were carried out on sintered samples. Single phase form was evidenced for each sintered materials. The best value of conductivity at 700 degrees C amounted to 1.10 x 10(-2) Omega(-1) cm(-1) for Ce0.85Er0.O-3(2-delta) sample. Corresponding activation energies of conductivity amounted to 0.28 eV in the temperature range 500-700 degrees C. (C) 2015 Elsevier B.V. All rights reserved.