583 research outputs found

    DIVERSIDAD DE LOS NEMATODOS DE TETRA COLA ROJA ASTYANAX AFF. PARANAE (TELEOSTEI: CHARACIDAE) DE SITIOS CONTAMINADOS DE UN SISTEMA DE RÍO TROPICAL

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    Aquatic systems are affected by a great variety of anthropogenic activities that alter the water quality through the introduction of organic and inorganic pollutants, consequently impacting all trophic levels of a biological community. The relationship between parasite species diversity and organic pollution in the high Paraná River basin, Paraná, Brazil was investigated during two seasons (Winter and Summer) of 2011. A total of 114 red-tail-lambari (Astyanax aff. paranae Eigenmann, 1914) were sampled from a non-impacted location (Perobas Reserve) and from impacted regions (agricultural and urban regions, upstream and downstream the city of Campo Mourão, respectively). The nematode Spinitectus yorkei Travassos, Artigas & Pereira, 1928 was found on the preserved area, while the nematode Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas & Pereira, 1928 was found only on the severely polluted areas. The variability of the prevalence index suggests that the structure of the parasite community is affected at different ways by the same levels of pollutants on the water. The observed results assume that the alteration in parasite diversity can be related to increased organic pollution, and that the differences in the parasite community from different environments can be related to biotic stress.Los sistemas acuáticos se ven afectados por una gran variedad de actividades antropogénicas que alteran la calidad del agua a través de la introducción de contaminantes orgánicos e inorgánicos, por consiguiente, afectan a todos los niveles de la comunidad biológica. De esta forma, la relación entre la diversidad de especies de parásitos y la contaminación orgánica en la cuenca del alto Paraná, Paraná, Brasil, se investigó en dos temporadas (invierno y verano) de 2011. Un total de 114 tetra cola roja (Astyanax aff. paranae Eigenmann, 1914) se muestrearon en un sitio no impactado (Reserva Perobas) y en regiones impactadas (zonas agrícolas y urbanas, aguas arriba y aguas abajo de la ciudad de Campo Mourão, respectivamente). El nematodo Spinitectus yorkei Travassos, Artigas y Pereira, 1928 se encuentran en la zona protegida, mientras que el nematodo Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas y Pereira, 1928 se encuentran sólo en las zonas gravemente contaminadas. La variabilidad del índice de prevalencia sugiere que la estructura de la comunidad de parásitos se ve afectada en diferentes formas por el mismo nivel de contaminantes en el agua. Los resultados observados asumen que la alteración en la diversidad parasitaria puede estar relacionada con el aumento de la contaminación orgánica, y que la respuesta de la comunidad de parásitos a las tensiones ambientales puede ser utilizada como bioindicadora

    Performance of geosynthetics as reinforcement in unpaved roads

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    O trabalho teve como objetivo avaliar o comportamento de estradas não pavimentadas construídas sobre solos moles reforçadas com diferentes geossintéticos. Foram selecionadas três estradas não pavimentadas que apresentassem um trecho com baixa capacidade de suporte de carga. A flecha foi medida pelo método fotográfico para cada número de passadas, nas condições com e sem reforço, e submetido à análise de variância, pelo teste de F, a 5% de probabilidade, e quando houve diferença significativa entre os tratamentos, suas médias foram comparadas pelo teste de Tukey. Posteriormente, realizou-se o cálculo da razão de benefício de tráfego fornecida pela inclusão do reforço. O geossintético não tecido, quando inserido no interior do solo, contribui de modo significativo para a redução das flechas, principalmente nos solos do trecho das estradas I e III. O geossintético tecido contribui para a redução das flechas, principalmente nos solos do trecho da estrada III. A geogrelha não contribui para a redução das flechas. A razão de benefício de tráfego para os reforços utilizados foram superiores a um, com valores médios de 1,28 para o trecho da estrada I, reforçado com geossintético não tecido, 1,54 para o trecho da estrada II, reforçado com geossintético tecido e de 2,7 para o trecho da estrada III, reforçado com geossintético tecido.The objective of this study was to evaluate the performance of unpaved roads built on soft soils reinforced with different geosynthetic materials. We selected three sections of unpaved roads with low load-bearing capacity. Vertical displacement (rut depth) was visually measured (photographs) for each number of passes on soils with and without reinforcement. The data underwent variance analysis by the F-test at 5% probability; when significant, means were compared by the Tukey’s test. Subsequently, we calculated traffic benefit ratio (TBR) or improvement factor due to the use of each reinforcement material. Non-woven geosynthetic materials reduced significantly the rut depths, mainly within the road sections I and III; by contrast, geosynthetic woven materials contributed in road section III. Moreover, geogrid use had no contribution to rut depth reductions. The TBR by using the reinforcements studied here showed values higher than one, with averages of 1.28 for road section I reinforced with geosynthetic nonwoven material, 1.54 for road section II reinforced with geosynthetic woven material, and 2.7 for road section III reinforced with geosynthetic woven

    Antiproliferative activity of neem leaf extracts obtained by a sequential pressurized liquid extraction

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    Azadirachta indica A. Juss (neem) extracts have been used in pharmaceutical applications as antitumor agents, due to their terpenes and phenolic compounds. To obtain extracts from neem leaves with potential antiproliferative effect, a sequential process of pressurized liquid extraction was carried out in a fixed bed extractor at 25◦C and 100 bar, using hexane (SH), ethyl acetate (SEA), and ethanol (SE)assolvents. Extractions using only ethanol(EE) was also conducted to compare the characteristics of the fractionated extracts. The results obtained by liquid chromatography-electrospray ionization mass spectrometry suggested a higher concentration of terpenes in the SEA extract in comparison to SH, SE, and EE extracts. Therefore, antiproliferative activity showed that SEA extracts were the most efficient inhibitor to human tumor cells MCF-7, NCI-H460, HeLa, and HepG2. Hepatocellular cells were more resistant to SH, SEA, SE, and EE compared to breast, lung, hepatocellular, and cervical malignant cells. Neem fractioned extracts obtained in the present study seem to be more selective for malignant cells compared to the non-tumor cells.Klebson Silva Santos thanks CAPES (Process: PDSE 99999.003409/15-5) for the financial support during his Ph.D. studies in Portugal. Authors are grateful to CAPES, and FAPITEC (EDITAL CAPES/FAPITEC Nº 11/2016–PROEF/Processo de AUXPE 88881.157437/2017-01) for the financial support. The study was also carried out with financial support from FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

    OTIMIZAÇÃO DE PORTFÓLIOS: ANÁLISE DE EFICIÊNCIA

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    This article aims to analyze the behavior of a portfolio of assets selected by Data Envelopment Analysis (DEA), optimized by the Sharpe approach, and compare it to portfolios of assets obtained only by DEA or the Sharpe approach. To do that, we used the DEA model to assess the efficiency of shares of the São Paulo Stock Exchange (Bovespa), employing return, variance and other indicators such as input and output variables. Also, we used the Sharpe approach to optimize the portfolio composition. In the comparison of portfolios, we noted that the resulting combination of both models performed better than the portfolios optimized by only one of the models

    nutrition and performance in football

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    Nutrition is an undeniable part of promoting health and performance among football (soccer) players. Nevertheless, nutritional strategies adopted in elite football can vary significantly depending on culture, habit and practical constraints and might not always be supported by scientific evidence. Therefore, a group of 28 Portuguese experts on sports nutrition, sports science and sports medicine sought to discuss current practices in the elite football landscape and review the existing evidence on nutritional strategies to be applied when supporting football players. Starting from understanding football?s physical and physiological demands, five different moments were identified: preparing to play, match-day, recovery after matches, between matches and during injury or rehabilitation periods. When applicable, specificities of nutritional support to young athletes and female players were also addressed. The result is a set of practical recommendations that gathered consensus among involved experts, highlighting carbohydrates periodisation, hydration and conscious use of dietary supplements.D915-7373-ED16 | Cesar LeaoN/

    Dielectric Screening in Atomically Thin Boron Nitride Nanosheets

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    Two-dimensional (2D) hexagonal boron nitride (BN) nanosheets are excellent dielectric substrate for graphene, molybdenum disulfide and many other 2D nanomaterials based electronic and photonic devices. To optimize the performance of these 2D devices, it is essential to understand the dielectric screening properties of BN nanosheets as a function of the thickness. Here, electric force microscopy along with theoretical calculations based on both state-of-the-art first-principles calculations with van der Waals interactions under consideration and non-linear Thomas-Fermi theory models are used to investigate the dielectric screening in high-quality BN nanosheets of different thicknesses. It is found that atomically thin BN nanosheets are less effective in electric field screening, but the screening capability of BN shows a relatively weak dependence on the layer thickness

    Biochemical characterization and low-resolution SAXS shape of a novel GH11 exo-1,4-β-xylanase identified in a microbial consortium

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    Biotechnologies that aim to produce renewable fuels, chemicals, and bioproducts from residual ligno(hemi)cellulosic biomass mostly rely on enzymatic depolymerization of plant cell walls (PCW). This process requires an arsenal of diverse enzymes, including xylanases, which synergistically act on the hemicellulose, reducing the long and complex xylan chains to oligomers and simple sugars. Thus, xylanases play a crucial role in PCW depolymerization. Until recently, the largest xylanase family, glycoside hydrolase family 11 (GH11) has been exclusively represented by endo-catalytic β-1,4- and β-1,3-xylanases. Analysis of a metatranscriptome library from a microbial lignocellulose community resulted in the identification of an unusual exo-acting GH11 β-1,4-xylanase (MetXyn11). Detailed characterization has been performed on recombinant MetXyn11 including determination of its low-resolution small angle Xray scattering (SAXS) molecular envelope in solution. Our results reveal that MetXyn11 is a monomeric globular enzyme that liberates xylobiose from heteroxylans as the only product. MetXyn11 has an optimal activity in a pH range from 6 to 9 and an optimal temperature of 50 oC. The enzyme maintained above 65% of its original activity in the pH range 5 to 6 after being incubated for 72 h at 50 oC. Addition of the enzyme to a commercial enzymatic cocktail (CelicCtec3) promoted a significant increase of enzymatic hydrolysis yields of hydrothermally pretreated sugarcane bagasse (16% after 24 h of hydrolysis)

    Evidence of niche partitioning under ontogenetic influences among three morphologically similar siluriformes in small subtropical streams

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    Ontogenetic influences in patterns of niche breadth and feeding overlap were investigated in three species of Siluriformes (Heptapterus sp., Rhamdia quelen and Trichomycterus poikilos) aiming at understanding the species coexistence. Samplings were conducted bimonthly by electrofishing technique from June/2012 to June/2013 in ten streams of the northwestern state of Rio Grande do Sul, Brazil. The stomach contents of 1,948 individuals were analyzed by volumetric method, with 59 food items identified. In general Heptapterus sp. consumed a high proportion of Aegla sp., terrestrial plant remains and Megaloptera; R. quelen consumed fish, and Oligochaeta, followed by Aegla sp.; while the diet of T. poikilos was based on Simuliidae, Ephemeroptera and Trichoptera. Specie segregation was observed in the NMDS. Through PERMANOVA analysis feeding differences among species, and between a combination of species plus size classes were observed. IndVal showed which items were indicators of these differences. Niche breadth values were high for all species. The niche breadth values were low only for the larger size of R. quelen and Heptapterus sp. while T. poikilos values were more similar. Overall the species were a low feeding overlap values. The higher frequency of high feeding overlap was observed for interaction between Heptapterus sp. and T. poikilos. The null model confirmed the niche partitioning between the species. The higher frequency of high and intermediate feeding overlap values were reported to smaller size classes. The null model showed resource sharing between the species/size class. Therefore, overall species showed a resource partitioning because of the use of occasional items. However, these species share resources mainly in the early ontogenetic stages until the emphasized change of morphological characteristics leading to trophic niche expansion and the apparent segregation observed

    A list of land plants of Parque Nacional do Caparaó, Brazil, highlights the presence of sampling gaps within this protected area

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    Brazilian protected areas are essential for plant conservation in the Atlantic Forest domain, one of the 36 global biodiversity hotspots. A major challenge for improving conservation actions is to know the plant richness, protected by these areas. Online databases offer an accessible way to build plant species lists and to provide relevant information about biodiversity. A list of land plants of “Parque Nacional do Caparaó” (PNC) was previously built using online databases and published on the website "Catálogo de Plantas das Unidades de Conservação do Brasil." Here, we provide and discuss additional information about plant species richness, endemism and conservation in the PNC that could not be included in the List. We documented 1,791 species of land plants as occurring in PNC, of which 63 are cited as threatened (CR, EN or VU) by the Brazilian National Red List, seven as data deficient (DD) and five as priorities for conservation. Fifity-one species were possible new ocurrences for ES and MG states
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