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Search Results: 1 - 10 of 6052 matches for " Artur Paiva Coutinho "
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Tracing Water Flow and Colloidal Particles Transfer in an Unsaturated Soil  [PDF]
Dieuseul Prédélus, Laurent Lassabatere, Artur Paiva Coutinho, Cédric Louis, Thomas Brichart, Erij Ben Slimène, Thierry Winiarski, Rafael Angulo-Jaramillo
Journal of Water Resource and Protection (JWARP) , 2014, DOI: 10.4236/jwarp.2014.67067
Abstract:

In recent years, many studies have been carried out on colloidal particle transfer in the unsaturated zone because they can be a risk to the environment either directly or as a vector of pollutants. A study was conducted on the influence of porous media structure in unsaturated conditions on colloidal particle transport. Three granular materials were set up in columns to replicate a fluvio-glacial soil from the unsaturated zone in the Lyon area (France). It is a sand, a bimodal mixture in equal proportion by weight of sand and gravel, and a fraction of bimodal mixture. Nanoparticles of silica (SiO2-Au-FluoNPs), having a hydrodynamic diameter between 50 and 60 nm, labeled by organic fluorescent molecules were used to simulate the transport of colloidal particles. A nonreactive tracer, bromide ion (Br-) at a concentration of C0,s = 10-2 M was used to determine the hydrodispersive properties of porous media. The tests were carried out first, with a solution of nanoparticles (C0,p = 0.2 g/L) and secondly, with a solution of nanoparticles and bromine. The transfer model based on fractionation of water into two phases, mobile and immobile, MIM, correctly fits the elution curves. The retention of colloidal particles is greater in the two media of bimodal particle size than that in the sand, which clearly demonstrates the role of textural heterogeneity in the retention mechanism. The increase in ionic strength produced by alimenting the columns with colloidal particle suspension in the presence of bromide, increases retention up to 25% in the sand. The total concentration profile of nanoparticles collected at the end of the experiment shows that the colloidal particles are retained primarily at the entrance of the columns. Hydrodispersive calculated parameters indicate

Vadose Zone Heterogeneity Effect on Unsaturated Water Flow Modeling at Meso-Scale  [PDF]
Artur Paiva Coutinho, Laurent Lassabatere, Thierry Winiarski, Jaime Joaquim da Silva Pereira Cabral, Antonio Celso Dantas Antonino, Rafael Angulo-Jaramillo
Journal of Water Resource and Protection (JWARP) , 2015, DOI: 10.4236/jwarp.2015.74028
Abstract: The understanding of unsaturated flow in heterogeneous formations is a prerequisite to the understanding of pollutant transfer in the vadose zone and the proper management of infiltration basins settled over such heterogeneous formations. This study addresses the effect of lithological heterogeneity of a glaciofluvial deposit on flow in the vadose zone underneath an infiltration basin settled in the Lyon suburbs. The basin had already been the subject of several previous studies, some of which demonstrated the impact of soil heterogeneity. But all of them were only based on the sedimentological study of a trench and no study addressed the potential spatial variability of results due to the spatial variability of soil heterogeneity. In this study, we model flow in the vadose zone for several case studies, including drainage, water infiltration during a rainfall event, and a complete meteorological chronic. These calculations were conducted for several sections, previously characterized in the basin using GPR and sedimentological study and compared with a blank (homogeneous section). The results clearly show that heterogeneity impacts unsaturated flow and that these impacts depend upon the section considered. Some geometrical architectural and textural parameters were proposed to explain the spatial variability and effect of the soil heterogeneity on unsaturated flow, thus establishing the first step towards modeling unsaturated flow in the basin at the meso-scale.
Dendritic Cells in Cord Blood Transplantation: A Review
Marta Isabel Pereira,Artur Paiva
Stem Cells International , 2011, DOI: 10.4061/2011/539896
Abstract: Dendritic cells (DCs) are a heterogeneous population of antigen-presenting cells derived from hematopoietic progenitors that bridge the transition between the innate and adaptive immune responses, while maintaining self-tolerance and Th1/Th2 homeostasis, by priming other cells in either an immunogenic or tolerogenic direction. Through their role in both innate and adaptive immunity, DCs play a major part in transplant engraftment and rejection and in graft-versus-host disease (GvHD). Preferentially tolerogenic or immunogenic DC subtypes offer targets for immunotherapy, to optimize transplant success rates and prolong disease-free and overall survival. Cord blood DCs are immature and preferentially tolerogenic, due to maternal-fetal tolerance, leading to better graft acceptance and immune reconstitution and explaining the lower incidence and severity of GvHD in CB transplantation, despite donor-host mismatching. Manipulation of DC maturation and cell loading with tumor-antigens can direct antitumor immunity and target minimal residual disease, as demonstrated for acute myeloid leukemia, optimizing the graft-versus-leukemia effect. 1. Dendritic Cells Dendritic cells (DCS) are a heterogeneous population of potent lineage-negative HLA-DR+ antigen-presenting cells (APCs), derived from CD34+ hematopoietic progenitors that are present in small numbers in solid tissues and peripheral blood, and that bridge the transition between the innate immune response and adaptive responses, through their activation of CD4+ T-cells, CD8+ T-cells, and B-cells, while maintaining self-tolerance. Recent data suggest that DCS arise from multilymphoid progenitors, along with lymphoid cells, monocytes, and macrophages [1], contradicting the classic and widely accepted model of early lymphoid-myeloid lineage segregation between the two main DC subsets, which can be differentiated through the expression of the inactivated-C3b receptor 4 (complement transmembrane protein) integrin alpha X chain (ITGAX or CD11c). This model postulates that CD11c? CD123high CD33? CD16? plasmacytoid dendritic cells (pDC) derive from a lymphoid progenitor cell, whereas CD11c+ CD123dim CD33+ CD16? myeloid dendritic cells (mDC) originate in a myeloid precursor cell [2–4]; the mDC subset can be further divided into distinct subpopulations, according to the expression of blood dendritic cell antigens—BDCA1+ (CD1c+) DC and BDCA3+ (CD141+) DC. The remaining BDCAs, BDCA2, and BDCA4 are expressed by pDC [4]. A third subtype of DC with a distinct immunophenotype has been described, comprising monocytoid-related
PRODU O CIENTíFICA BRASILEIRA EM GEST O DE OPERA ES NO PERíODO 2000-2010
Ely Laureano Paiva,Luiz Artur Ledur Brito
Revista de Administra??o de Empresas , 2013,
Abstract: The aim of this study is to analyze issues in Operations Management and the methodology employed by Brazilian researchers in this field. The analysis of the literature traced two complementary axes: relevance and rigor. We covered the last ten years by examining the main Brazilian journals in Business Administration and analyzing articles published in the main international journals in OM as well. The study found a certain level of convergence between the issues in the articles published by Brazilian authors in both groups of journals and the importance of supply chain management and operations strategies. The main challenge facing Brazilian researchers concerns the methodological changes in OM studies that are currently in progress on an international level.
Estoque de carbono em cerrado sensu stricto do Distrito Federal
Paiva, Artur Orelli;Rezende, Alba Valéria;Pereira, Reginaldo Sergio;
Revista árvore , 2011, DOI: 10.1590/S0100-67622011000300015
Abstract: the objective of this study was to estimate the carbon stock of the aerial section (stems, branches and litter) and belowground (roots and soil) of woody vegetation in a cerrado sensu stricto located on água limpa farm, at university of brasilia, federal district, brazil. the studied area was sampled from 20 x 50m plots, allocated systematically. in each plot, it was uplifted all the woody shrubby-arboreous individuals, being live and stand dead, with at least 5 cm of diameter taken at 30 cm from the ground level. it was also performed collections of litter biomass, roots biomass (fine, medium and thick) and density and soil carbon concentration. the maximum depth adopted for collection of belowground section was 2 meters. most of the carbon corresponded to soil compartment (88.7%), which was much more than the roots (7.3%), where the concentrations were 271.23 and 22.38 tons per hectare, respectively. stems and branches totalized 8.60 tons of carbon per hectare and litter, 3.62 tons of carbon per hectare.
Isolation of filamentous fungi from public telephones of the Metropolitan region of the city of Recife, PE, Brazil
Coutinho, Flavia Paiva;Cavalcanti, Marilene da Silva;Cordeiro Neto, Francisco;
Brazilian Journal of Microbiology , 2007, DOI: 10.1590/S1517-83822007000200027
Abstract: fungi can inhabit our organism without causing any harm, but they show themselves when the immunological system is compromised. in this study, a survey of the occurrence of filamentous fungi was carried out in public telephones of the metropolitan region of the city of recife, pe, brazil. this showed the public phones as a possible mean of transmission of fungal diseases among humans. samples from the environment, audios, speakers and keyboards were taken at the airport, mall, subway and bus station in the months of october/2003 (dry season) and june/2004 (rainy season), totaling 120 samples. the procedure of identification of species was carried out through conventional taxonomy. thirty-four genera were isolated, totaling 73 species, the majority belonging to the anamorphic fungi (91.78%), followed by the ascomycota (6.85%) and the zygomycota (1.37%). there was no significant difference in the proportion of species between the dry and rainy seasons, with 46 and 53 species identified, respectively. due to the lack of maintenance, or inadequate cleaning of public telephones, the fungi present in these appliances may cause mycosis in the users as these telephones are used by people from different social classes and variable habits, both healthy and immunocompromised.
Genetic Correlation between Agronomically Important Traits in Yellow Passion Fruit  [PDF]
Leonarda Grillo Neves, Claudio Horst Bruckner, Marcelo Coutinho Pican?o, Severino de Paiva Sobrinho, Kelly Lana Araújo, Petterson Baptista da Luz, Marco Antonio Aparecido Barelli, Willian Krause
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.411262
Abstract:

Breeding programs have sought to determine the minimum period of genotype evaluation, which is a long term-process. The objective of this work was to determine the association between qualitative traits of yellow passion fruit (Passiflora edulis Sims) and relate maturity to other characteristics. To carry out this work, 113 families of full-sibs and half-sibs were planted in Viçosa (MG), Brazil, in a randomized block experimental design arranged in sets (treatment groups). The association between the analyzed characteristics was studied using path analysis and canonical correlation techniques. It was found that lower-yielding but larger-fruit bearing genotypes of passion fruit plant also require more days until reaching anthesis. Round-shaped fruits are linked to higher contents of total soluble solids. More intense pulp color also indicates higher contents of total soluble solids. The riper the fruit, the more intensely orange is the color of the pulp. The ratio between the levels of total soluble solids and total titrimetric acidity was the main determinant of pulp color

Filamentous fungi isolated from the rhizosphere of melon plants (Cucumis melo L. cv. Gold Mine) cultivated in soil with organic amendments
Coutinho, Flavia Paiva;Cavalcanti, Maria Auxiliadora de Queiroz;Yano-Melo, Adriana Mayumi;
Acta Botanica Brasilica , 2010, DOI: 10.1590/S0102-33062010000100032
Abstract: rhizosphere soil samples were collected in a semiarid area, in the region of the s?o francisco river valley, petrolina, pernambuco state, brazil, to study the diversity of filamentous fungi in a soil cultivated with melon (cucumis melo l. cv. gold mine) and receiving different organic amendments: treatment 1 (control, without organic compost); t2 (77% coconut fiber, 20% goat manure and 3% k2so4); t3 (10% ricinus communis leaves and stems, 50% pennisetum purpureum leaves and 40% goat manure); t4 (77% coconut fiber, 20% goat manure and 3% termophosphate); t5 (47% pennisetum purpureum leaves, 50% goat manure and 3% k2so4); and t6 (57% pennisetum purpureum leaves, 40% goat manure and 3% termophosphate). fungal isolation was carried out by the serial dilution technique to 1:1000. the sorensen index of similarity, frequency and distribution of the fungi were evaluated. seventy-eight species of filamentous fungi were isolated and identified, plus several basidiomycota (04) and mycelia sterilia (02). the predominant genera were aspergillus and penicillium, with 15 and 13 species, respectively. a greater number of species was found in the sowing period (49), and in relation to the organic fertilization, treatment 6 provided the greatest species diversity (43 species). most of the species are saprobes and only a few are considered to be potential pathogens on melon plants, such as fusarium oxysporum, f. solani and myrothecium roridum.
Phosphate-solubilizing fungi isolated from a semiarid area cultivated with melon (Cucumis melo L. cv. gold mine)
Coutinho, Flavia Paiva;Cavalcanti, Maria Auxiliadora de Queiroz;Yano-Melo, Adriana Mayumi;
Acta Botanica Brasilica , 2011, DOI: 10.1590/S0102-33062011000400020
Abstract: considering that little is known about the occurrence of phosphate-solubilizing fungi from areas cultivated with melon, the phosphate solubilization ability of filamentous fungi isolated in these areas was evaluated. three hundred and eighteen filamentous fungal isolates belonging to 23 genera were evaluated, besides aphyllophorales and mycelia sterilia. from those, 52 were able to solubilize p: aphyllophorales (2), aspergillus (34), penicillium (10) and rhizopus (6). these results will contribute to subsidizing further research regarding the capacity of these fungi to solubilize other sources of phosphate applied to the melon crop, as well as indicate the need for a screening program to select those with higher capacity and potential for solubilization.
Strain specific variation of outer membrane proteins of wild Yersinia pestis strains subjected to different growth temperatures
Abath, Frederico Guilherme Coutinho;Almeida, Alzira Maria Paiva de;Ferreira, Luís Carlos de Souza;
Memórias do Instituto Oswaldo Cruz , 1990, DOI: 10.1590/S0074-02761990000100018
Abstract: three yersinia pestis strains isolated from humans and one laboratory strain (ev76) were grown in rich media at 28§c and 37§c and their outer membrane protein composition compared by sodium dodecyl sulphate polyacrylamide gel electrophoresis (sds-page). several proteins with molecular weights ranging from 34 kda to 7 kda were observed to change in relative abundance in samples grown at different temperatures. at least seven y. pestis outer membrane proteins showed a temperature-dependent and strain-specific behaviour. some differences between the outer membrane proteins of full-pathogenic wild isolates and the ev76 strain could aldso be detected and the relevance of this finding on the use of laboratory strains as a reference to the study of y. pestis biological properties is discuted.
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