A profile analysis of the top Brazilian Computer Science graduate programs

Analyzing the research productivity of a country, an academic institution or even a single research group contributes to understand how science evolves and discovers new research perspectives, since such efforts usually reveal key aspects that can be improved, avoided or even applied to other contexts. In this article, we present a detailed analysis of the top Brazilian Computer Science graduate programs. The analysis involves profile data on faculty members (e.g., career length and number of mentored students) and on the quality of their research efforts, assessed using the quality of their publications and collaboration patterns. The objective is to uncover factors that explain the strengths and weaknesses of graduate programs. Results show that the highest ranked programs include more experienced faculty members, who have mentored more Ph.D. students. We also show that programs target distinct publication venues, with the best ranked ones focusing on higher quality conferences and journals. By analyzing collaboration patterns, we show that intra-program relationships occur quite naturally whereas inter-program ones are still very incipient.     

Comparative study of H2 production by ethanol steam reforming on Ce2Zr1.5Co0.5O8−δ and Ce2Zr1.5Co0.47Rh0.07O8−δ: Evidence of the Rh role on the deactivation process

The catalytic performance of Ce₂Zr_1.5Co_0.5O_8−δ and Ce₂Zr_1.5Co_0.47Rh_0.07O_8−δ mixed oxides was evaluated comparing the influence of Rh insertion for hydrogen production in ethanol steam reforming. Rh doped and not doped catalysts were prepared by the pseudo sol–gel like method and were characterized using DRX, TPR, SEM, and TPO. For the Rh-doped catalyst, it was found an easier structure reducibility allowing to avoid a reducing activation treatment. The reactivity results show that lifetime of Ce₂Zr_1.5Co_0.47Rh_0.07O_8−δ mixed oxide is more than 30 times higher, compared to the Ce₂Zr_1.5Co_0.5O_8−δ mixed oxide. Catalytic tests under various water/ethanol ratios and ethylene and acetaldehyde steam reforming evidence that the deactivation process for the catalytic systems is not only related to carbon deposits but also to carbonate species, which can be form from an acetaldehyde reaction sequence. The benefic effect of rhodium would ascribe to its ability to avoid carbonates formation under reaction, preventing the blocking of the active oxygen vacancies of the mixed oxide support.     

Morphology,structure and photowettability of TiO2 coatings doped with copper and fluorine

The work reports synthesis, structure and properties of doubly doped titanium dioxide coatings activated by ultraviolet and visible light. Copper within a concentration range of 0.4–3.4 at% and fluorine within a concentration range of 1.7–9.4 at% were introduced as dopants. The coatings were prepared with the help of radiofrequency plasma enhanced chemical vapor deposition technique with a single precursor compound providing both dopants and titanium (IV) chloride being a source of titanium. Elemental composition and chemical bonding analyses of the coatings were carried out with the help of X-ray photoelectron spectroscopy. The results indicate that both admixtures are chemically bound to the TiO₂ matrix – a notion confirmed by Fourier transform infrared spectroscopy. Phase composition studies, performed with a low angle X-ray diffraction method, revealed a presence of a threshold concentration of the dopants affecting the coatings crystallinity. Surface morphology and its topography were studied with the help of scanning electron microscopy and atomic force microscopy. Several coatings exhibited a superhydrophilic effect upon relatively short time of illumination.     

Effect of increasing anode surface area on the performance of a single chamber microbial fuel cell

The anode material and its configuration represent an important parameter in a microbial fuel cell (MFC), as it influences the development of the microbial community involved in the electrochemical bio-reactions.The aim of this work was to evaluate single chamber microbial fuel cells (SCMFCs) with high anode surface area, achieved by using packed beds of irregular graphite granules. The performance of the SCMFC with the packed bed anode configuration was studied using a mixed microorganism culture from real wastewaters in batch and continuous mode operation.The current output was found to increase with the increase in thickness of the anode bed and with the approximate anode area. The best performance was obtained with the 3 cm anode bed depth SCMFC. When the latter was operated in batch mode, Coulombic efficiencies varied from 30% to 74%, depending upon feed COD. In continuous mode operation, the COD removal was 89% and Coulombic efficiency 68% with a feed COD of 50 ppm, and at a flow rate of 0.0028 cm³ min^?1. Power performance was also reasonable with a volumetric power density of 1.3 W m^?3, with respect to the net anodic volume (12.5 cm³). Comparable performance was achieved with real wastewater. Over the duration of tests current output was stable. The investigation performed in this study represent a step forward for implementing real applications of MFC technology. A model of the current distribution in the packed bed electrode was applied, which correlates the effective utilization of the electrode to its specific area, solution conductivity and slope of the polarization curve. This model could function as a starting point in designing appropriate electrode geometries.     

Applicability of quantitative polymerase chain reaction (qPCR) assays for common bean authentication in processed food

Food authentication by quantitative polymerase chain reaction (qPCR) methods assures food quality. The aim was to evaluate three qPCR assays for DNA quantification after heat processing of common bean grains, genus-specific FAS assay for Phaseolus, species-specific LEC assay for common bean (Phaseolus vulgaris) and genetically modified (GM) event-specific FGM assay for Embrapa 5.1 event GM common bean. FAS assay showed high stability among Phaseolus genus samples. Common bean grains were heat-treated in autoclave (at 120 °C for 15–60 min) and target DNA copy number decreased as processing time increased. Even with DNA degradation, qPCR assays were capable to detect low DNA quantity, and the limit of detection was 100 copy number. Mean efficiency value of FGM assay was 92% in the presence of background DNA. Background DNA did not cause any interference, and 0.39% of GM material can be detected. These qPCR assays are able to quantify common bean in processed food.     

Influence of low-level laser associated with osteogenic proteins recombinant human BMP-2 and Hevea brasiliensis on bone repair in Wistar rats

This study analyzed the newly formed bone tissue after application of recombinant human BMP-2 (rhBMP-2) and P-1 (extracted from Hevea brasiliensis) proteins, 2 weeks after the creation of a critical bone defect in male Wistar rats treated or not with a low-intensity laser (GaAlAs 780 nm, 60 mW of power, and energy density dose of 30 J/cm(2)). The animals were divided into two major groups: (1) bone defect plus low-intensity laser treatment and (2) bone defect without laser irradiation. The following subgroups were also analyzed: (a) 5 μg of pure rhBMP-2; (b) 5 μg of pure P-1 fraction; (c) 5 μg of rhBMP-2/monoolein gel; (d) 5 μg of P-1 fraction/monoolein gel; (e) pure monoolein gel. Comparisons of the groups receiving laser treatment with those that did not receive laser irradiation show differences in the areas of new bone tissue. The group treated with 5 μg of rhBMP-2 and laser irradiation was not significantly different (P >0.05) than the nonirradiated group that received the same treatment. The irradiated, rhBMP-2/monoolein gel treatment group showed a lower area of bone formation than the nonirradiated, rhBMP-2/gel monoolein treatment group (P < 0.001). The area of new bone tissue in the other nonirradiated and irradiated groups was not significantly different (P > 0.05). Furthermore, the group that received the 5 μg of rhBMP-2 application showed the greatest bone formation. We conclude that the laser treatment did not interfere with the area of new bone tissue growth and that the greatest stimulus for bone formation involved application of the rhBMP-2 protein.     

Effect of carrier agents on the physical and thermal stability of freeze-dried passion fruit (Passiflora edulis f. flavicarpa) pulp

In this study, the physical and thermal stability of freeze-dried passion fruit (Passiflora edulis f. flavicarpa) pulp produced with different carrier agents was evaluated. Powders were produced using sucrose, fructose, ethanol, and maltodextrin as carrier agents and characterized by differential scanning calorimetry, morphology, moisture sorption curves, and sorption kinetics. The GAB (Guggenheim-Anderson-de Boer) model was suitable to mathematically describe the adsorption isotherms. The treatments that had maltodextrin as the additive exhibited reduced adsorption both in low- and in high-water activities, promoting the reduction of the moisture content in the monolayer (X_m) and enhancing the stability of the powder product. The combination of sucrose and ethanol increased the glass transition temperature of the system compared to the in natura pulp. Treatments with fructose did not improve the sorption characteristics of the powders, featuring an amorphous structure. The kinetic curves, ratio of the increase of the water content against the storage time, of the passion fruit pulp treated with 10 g of maltodextrin/100 g of pulp and with 5 g of sucrose and 10 g of maltodextrin/100 g of pulp showed reduced adsorption and similar behaviors for water activity values of 0.113, 0.529, 0.753, and 0.903.