33 resultados para meio semi-seletivo

em Universidade Federal do Rio Grande do Norte(UFRN)


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SILVA, J. L. M. da; SAMPAIO, L. M. . Eficiência, Gestão e Meio Ambiente na Carcinicultura do Rio Grande do Norte. In: Congresso da Sociendade Brasileira de Economia, Administração e Sociologia Rural - SOBER, 40., 2007, Londrina. Conhecimentos para a Agricultura do Futuro, 2007.

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The response of zooplankton assemblages to variations in the water quality of four man-made lakes, caused by eutrophication and siltation, was investigated by means of canonical correspondence analysis. Monte Carlo simulations using the CCA eingenvalues as test statistics revealed that changes in zooplankton species composition along the environmental gradients of trophic state and abiogenic turbidity were highly significant. The species Brachionus calyciflorus, Thermocyclops sp. and Argyrodiaptomus sp. were good indicators of eutrophic conditions while the species Brachionus dolabratus, Keratella tropica and Hexarthra sp. were good indicators of high turbidity due to suspended sediments. The rotifer genus Brachionus was the most species-rich taxon, comprising five species which were associated with different environmental conditions. Therefore, we tested whether this genus alone could potentially be a better biological indicator of these environmental gradients than the entire zooplankton assemblages or any other random set of five species. The ordination results show that the five Brachionus species alone did not explain better the observed pattern of environmental variation than most random sets of five species. Therefore, this genus could not be selected as a target taxon for more intensive environmental monitoring as has been previously suggested by Attayde and Bozelli (1998). Overall, our results show that changes in the water quality of man-made lakes in a tropical semi-arid region have significant effects on the structure of zooplankton assemblages that can potentially affect the functioning of these ecosystems

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Nickel alloys are frequently used in applications that require resistance at high temperatures associated with resistance to corrosion. Alloys of Ni-Si-C can be obtained by means of powder metallurgy in which powder mixtures are made of metallic nickel powders with additions of various alloying carriers for such were used in this study SiC, Si3N4 or Si metal with graphite. Carbonyl Ni powder with mean particle size of 11 mM were mixed with 3 wt% of SiC powders with an average particle size of 15, 30 and 50 μm and further samples were obtained containing 4 to 5% by mass of SiC with average particle size of 15 μm. Samples were also obtained by varying the carrier alloy, these being Si3N4 powder with graphite, with average particle size of 1.5 and 5 μm, respectively. As a metallic Si graphite with average particle size of 12.5 and 5 μm, respectively. The reference material used was nickel carbonyl sintered without adding carriers. Microstructural characterization of the alloys was made by optical microscopy and scanning electron microscopy with semi-quantitative chemical analysis. We determined the densities of the samples and measurement of microhardness. We studied the dissociation of carriers alloy after sintering at 1200 ° C for 60 minutes. Was evaluated also in the same sintering conditions, the influence of the variation of average particle size of the SiC carrier to the proportion of 3% by mass. Finally, we studied the influence of variation of the temperatures of sintering at 950, 1080 and 1200 ° C without landing and also with heights of 30, 60, 120 and 240 minutes for sintering where the temperature was 950 °C. Dilatometry curves showed that the SiC sintered Ni favors more effectively than other carriers alloy analyzed. SiC with average particle size of 15 μm active sintering the alloy more effectively than other SiC used. However, with the chemical and morphological analyzes for all leagues, it was observed that there was dissociation of SiC and Si3N4, as well as diffusion of Si in Ni matrix and carbon cluster and dispersed in the matrix, which also occurred for the alloys with Si carriers and metallic graphite. So the league that was presented better results containing Si Ni with graphite metallic alloy as carriers, since this had dispersed graphite best in the league, reaching the microstructural model proposed, which is necessary for material characteristic of solid lubricant, so how we got the best results when the density and hardness of the alloy

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This research work intends to carry out a study focused on the dynamic between development, poverty reduction and conservation of natural resources. To consider this relationship to the region chosen was the micro-region of Eastern and Western Seridó in the state of Rio Grande do Norte. In recent years, several studies (Araújo, 2011; BASTOS, 2009) have pointed out that after a period of economic crisis in its tripodproductive, formed by the activities of farming, cotton farming, mining and faced in the eighties, this region of the State of Rio Grande do Norte, has not only shown signs of economic recovery but also improve their social indicators. On the other hand, studies of desertification as the view of the state of RN (produced in cooperation between the Government of RN and research institutions) and the Sustainable Development Plan of Seridó (ADES, 2000), indicate that there is an ongoing French process of degradation of natural resources that is capable of compromising the ability of sustaining such a system. To verify this reality and likely finding this relationship, this work is adopted for this study, the analysis of evolution of secondary data from official bodies such as the IBGE on HDI, per capita income and other social indicators between 2000 and 2009. Here is another time of the survey analysis of qualitative data collected from interviews with institutions of academic intervention in nature, researchers at the Federal University of Rio Grande do Norte (UFRN) State agencies that address the issue of the Middle Environment in Seridó: Institute for Sustainable Development of the NB (IDEMA) and the Brazilian Institute of Environment and the Amazon (IBAMA) and institutions of direct intervention in the region, as the Agency's Sustainable Development Seridó (adhesive) and the Joint Semi-Arid (ASA). After crossing data from quantitative and qualitative, it was found that the dynamics of the region's economic Seridó Potiguar partially answers the improvement of social indicators of poverty. Contribution by the State in this shared stock transfer income. Regarding the influence of productive restructuring in the region on issues of environment, it is noted that the ceramic tile industry, responsible for the absorption percentage of the population with limited ingress into the urban economy, given the low education, accounts for the increase of susceptibility to the ongoing process of desertification in North Seridó Rio Grande. We conclude finally that the guarantee of increased income, freedom and conservation of natural resources ensures primarily by changing the beliefs and values, especially on the part of the business sector, which use natural resources so predatory, aimed at maintaining their rates of return on investment. And concomitantly, the synchronization between technological change, through the use of new energy sources, and institutional change.

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Las experiencias colectivas como canales de acceso a mejores condiciones de vida, engendradas por los sectores populares y, especialmente, por las populaciones rurales, nos motivaron a la realización de esta investigación. Teniendo como unidad de análisis una cooperativa constituida por agricultores y agricultoras familiares, investigada por medio de un estudio de caso y como base teórica las concepciones de economía solidaria y popular, nuestra cuestión central fue comprender ¿cuales las prácticas adoptadas que han posibilitado su éxito? Para ello, partimos de la hipótesis de que el éxito de esas organizaciones depende de la aplicación de los principios cooperativistas, cuales sean: adhesión libre y voluntaria, democracia, participación, intercooperación, educación e información, preocupación con el entorno, autonomía e independencia; y de sus relaciones externas con el Estado y otras instituciones de apoyo. Para cumplir nuestro propósito, fueron seleccionados también algunos indicadores, una amuestra aleatoria de la población elegida y los representantes de las instituciones involucradas con la cooperativa. Siendo una investigación de carácter más cualitativa, pero usando dados cuantitativos, fueron utilizados para la coleta de los datos encuestas semi-estructuradas, cuestionarios con preguntas abiertas y cerradas, observaciones directas, registros fotográficos y análisis documentales. Los principales resultados encontrados indican que la hipótesis fue confirmada, o sea, el éxito de la cooperativa estudiada tuvo vinculación directa con la aplicación de los principios cooperativistas, con el acceso a los recursos públicos disponibles y con los apoyos de otras instituciones, generando beneficios socioeconómicos para los cooperados y externalidades positivas para el desenvolvimiento del entorno

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O tema proposto nesta tese vai ao encontro do atual debate em curso no Brasil e no mundo acerca de duas dimensões da cadeia agroalimentar: produção e consumo. Desse modo, as questões de como se dá essa relação frente às estratégias locais por diferentes atores, terá ênfase. Para isso, como campo empírico foram escolhidos três municípios localizados no território Centro-Sul do estado do Paraná: Irati, Inácio Martins e Fernandes Pinheiro que desde 2004 estão inseridos no Programa de Aquisição de Alimentos (PAA), mais especificamente na modalidade Compra com Doação Simultânea (CDS). A hipótese que embasa este estudo é de que o PAA poderá ser capaz de assumir um caráter estruturante - a partir do seu viés pedagógico, capacidade organizativa de produção, manutenção da diversidade ou resgate da policultura (e aqui se privilegia a agroecologia), bem como uma alternativa viável de acesso a um tipo de mercado (mercado institucional) -, não por altruísmo dos atores, mas por ser mais vantajoso ser parte integrante, do que estar à parte do processo, aliando a isso melhorias nas condições alimentares tanto das suas famílias, quanto das entidades receptoras. O objetivo principal foi analisar as relações sociais e as práticas alimentares de um grupo de agricultores(as) agroecológicos entre as responsáveis pelo recebimento dos alimentos doados buscando compreender se o PAA possibilita a Soberania e Segurança Alimentar e Nutricional (SSAN) de grupos sociais (como das famílias rurais) e das pessoas atendidas por estas entidades. A metodologia utilizada foi a de estudo de caso. Como procedimentos foram empregados entrevistas semi-estruturadas e aplicação de questionários como: Escala Brasileira de Insegurança Alimentar(EBIA) e Questionário de Frequência de Consumo Alimentar(QFCA). A amostra foi composta por agricultores(as)/ fornecedores(as) do PAA, nutricionistas e, coordenadora de uma das entidade dos seus produtos é, de fato, o que os mobiliza a continuar produzindo em maior diversidade e quantidade. Após a vivência dos(as) agricultores(as) /fornecedores de estarem inseridos no Programa foi possível para estes atores se sentirem parte do processo e, assim, repensar suas práticas de produção de alimentos, seja ela destinada ao autoconsumo, seja voltada à comercialização. Para além da discussão acerca da produção destinada ao autoconsumo, ficou claro o processo de recampesinização entre as famílias de agricultores(as). O processo de (re)conexão se apresenta de forma frágil, considerando, sobretudo, as considerações feitas pelas mediadoras. Trazer à tona o debate acerca da produção-consumo de alimentos, tanto na perspectiva de quem produz, como na de quem consome, e tomando por referência a operacionalização de políticas públicas, viabiliza a ampliação de debates e a concretização de ações mais contundentes numa perspectiva de minorar a situação de vulnerabilidade (social e alimentar) e de pobreza rural

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The purpose of this work is to analyze the knowledge relationships that articulate in projects of maintainable rural development construction for the paraiban semi-arid, analyzing the farmers daily practices and their relationship with the technological practices spread by ONGs. We took as empirical object the rural community of Lajedo de Timbaúba, municipal district of Soledade-PB, located in the very small region of paraiban Curimataú. It is a community where registers one of the first cases of maintainable rural development planning in the state of Paraíba. The analysis was centered on the farmers experiences of life in sustainability experience, trying to understand how they acquire new knowledge and how they interact with them. In methodological terms, it was considered feasible to place the knowledge interaction between the farmers and technicians from ONGs by placing the analysis according to Paulo Freire s questioning (2006): extension or communication? To understand the farmers daily practices, it was resorted to the theoretical contribution by Michel de Certeau (2008) in order to discern a microresistance movement of inversion/rejection/changing by the farmers in relation to their external knowledge. Just from the theoretical point of view and resorting to the imaginary social by Cornelius Castoriadis (1982), it was considered the way of living of the farmers researched, having as reference the experience in the material and symbolic production of their lives. It became indispensable, therefore, not to dissociate the knowledge relationships between farmers and technicians from ONGs from the sustainability concepts, maintainable rural development, and rural extension. The results of the study revealed that the farmers from Lajedo de Timbaúba while dealing with the technological practices proposed by ONGs that work in the community, express those practices from their daily logic, and they constitute them in survival strategies that are inserted in their own idiosyncrasy. It was verified, therefore, that the external knowledge presented by the proposals of sociability alternatives with the droughts in the perspective of maintainable development while placed in the farmers daily relationship, they are judged as advantageous or disadvantageous when they are confronted with their peculiar way of doing their daily work. The technological practices are incorporated, denied, or recreated starting from evaluative criteria related to the preservation of the soil and to the economical and social reproduction of the unit of production of family agriculture

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The number of disabled students, who have entered the university, in Brazil, since the beginning of this century, is undergoing a speed growth. It is a change that follows a global trend that spreads an inclusive education policy and that has had a profound impact on Brazil, with import results in field researches. This subject has been highlighted due to the significant amount of disabled students enrolled in college institutions (IES), although it is still modest the number of studies about it, especially in what matters the assistance given to the candidates to a university entrance examination. The aim of this paper is to investigate how effectively Natal s IES apply the rules established in Brazilian law concerning disabled students, especially MEC/GM Circular Warning n. 277/96, in what respects the conditions given to disabled students preparing to enter a college. The investigation followed a qualitative methodological approach with support on an exploratory study. The data recollection employed questionnaire, semi-structured interview and documental analyses, and the data have been organized and assessed following Minayo s (1996) stages. What concerns the results, it was observed that none of the ten colleges inquired confirmed to possess places exclusively to disabled candidates; six of them, however, offer Special Examining Board in the selection process of disabled candidates. Among eighteen college bills, only two of them offered specific information related to services and resources offered by IES to the candidates who ask for especial assistance concerning examination. During the interviews, four managers avowed the preoccupation in offering an equal selection process, but two of them proved not dominate the subject. In conclusion, the investigated institutions managers do not still seem to respect the rule that guarantees to disabled candidates equal conditions during all the process of the university entrance examination. With this work, we hope do help changing this focus and contribute to new studies on disabled persons studying for a degree

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Solid substrate cultivation (SSC) has become an efficient alternative towards rational use of agro industrial wastes and production of value-added products, mainly in developing countries. This work presents the production and functional application results of phenolic extracts obtained by solid substrate cultivation of pineapple (Ananas comosus L.) and guava (Psidium guajava L.) residues associated to soy flour and bioprocessed by Rhizopus oligosporus fungus. Two experimental groups were tested: (1) 9g of fruit residue and 1g of soy flour (A9 or G9); (2) 5g of fruit residue and 5g of soy flour (A5 or G5). After SSC, 100ml of distilled water was added to each Erlenmeyer flask containing 10g of bioprocessed material in order to obtain the phenolic extracts. Samples were taken every two days for total phenolic concentration (TPC) and antioxidant capacity evaluation by DPPH test during 12-day cultivation. The 2-day and 10-d ay extracts were selected and concentrated by ebullition until 1/10 of original volume was reached. After that, both non-concentrated and concentrated extracts were evaluated for their antimicrobial activity against Staphylococcus aureus and Salmonella enterica and a-amylase inhibitory capacity. It was observed an inverse relationship between total phenolic concentration (TPC) and antioxidant capacity during the cultivation. Besides that, the concentrated pineapple samples after two days were able to inhibit both pathogens tested, especially S. aureus. Guava concentrated extracts after 2 days showed expressive inhibition against S. enterica, but negative results against S. aureus growth. When it comes to a-amylase inhibition, A9 extracts after 2 days, both concentrated or not, completely inhibited enzyme activity. Similar behavior was observed for G9 samples, but only for concentrated samples. It was shown that concentration by ebullition positively affected the enzymatic inhibition of G9 and A9 samples, but on the other side, decreased antiamylase activity of A5 and G5 samples

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The aim of this work is to use a new technology in the treatment of produced wastewaters from oil industry. An unit for treat produced waters called UTMDIF, was designed, installed and operated in an industrial plant for treatment of effluents from oil industry. This unit operates by means of the method of separation of phase inversion and can become a promising alternative to solve the problem of oil/water separation. This method constitutes the basis of the working of a new design of mixersettler of vertical configuration which occupies small surface area. The last characteristic becomes specially important when there is limitation on the lay-out of the plant, for example, over maritime platforms to explore oil. This equipment in a semi-industrial scale treats produced wastewaters contaminated with oil at low concentrations (ranging from 30 to 150 mg/L) and throughputs of 320 m3/d (47,4 m3 m-2 h-1). Good results were obtained in oil/water separation which leads to the necessary specification to discharge those wastewaters. Besides, the non dependence of the efficiency of separation in spite of the salinity of the medium becomes the equipment an attractive new technology to treat wastewaters containing oil at low concentrations

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In northeastern semiarid, seasonality on precipitation temporal distribution, high intensity storm events and inadequate management of native vegetation can promote soil erosion. Vegetation removal causes soil surface exposure, reduces soil water storage capacity and can be the source degradation processes. In this context, this approach aims to analyze water and soil erosion processes on a 250 m2 undisturbed experimental plot with native vegetation, slope 2.5% by using 2006 and 2007 monitoring data. The site was instrumented to monitor rainfall, overland flow runoff and erosion by using a 5 m³ tank downstream the plot. Soil erosion monitoring was made by transported sediment and organic matter collection after each event. Field infiltration experiments were made at 16 points randomly distributed within the plot area by using a constant head infiltrometer during drought and rainy seasons, respectively. Infiltration data revealed high spatial and temporal variability. It was observed that during the beginning of the rainy period, 77% of the events showed runoff coefficient less than 0.05. As the rainy season began, soil water increase produced annual species germination. High intensity storms resulted in runoff coefficients varying between 0.33 and 0.42. Once the annual species was established, it was observed that approximately 39% of the events produced no runoff, which reflects an increase on soil water retention capacity caused by the vegetation. A gradual runoff reduction during the rainy season emphasizes the effect of vegetative density increase. Soil erosion observed data allowed to fit an empirical relationship involving soil loss and precipitation height, which was used to analyze the plot installation impact on soil erosion. Observed soil loss in 2006 and 2007 was 230 Kg/ha and 54 Kg/ha, respectively

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Environmental impacts are defined as the processes of social and ecological changes caused by nuisance ambient. In agriculture are diverse, and the intensive use of land and inappropriate agricultural practices causes negative effect on the environment besides affecting crop productivity and quality of life of man. So this study was objective to analyze parameters indicators of environmental impacts in the Cruzeta the Discrict Irrigation. During the period July 2007 to March 2008 samples were collected in lot 01 and 02 of the irrigation district. The monitoring was conducted in four sampling points, three (3) located in the irrigation channels and 1 (one) located in a cacimbão. Were monitored pH, CE, STD, SS, NO3-, OD, DT, PST, RAS, CT, Ca+2, Mg+2, Na+ and K+ and heavy metals. Analysis was performed, soil fertility, determining the infiltration rate, moisture content of soil and flow measurement. The results showed that the parameters considered most effective in evaluating the indicators of environmental impacts were: Suspended solid, turbidity, dissolved oxygen and Coliform termotelerantes. The concentrations of nitrate were below the limit established by CONAMA (2005). High levels of STD were found in the point P4. The risk of salinity in cacimbão Lot 02, the water was classified as Class II, or medium risk of salinity in the remaining points was classified as Class I. The iron and aluminum were found high concentrations in four sampling points independent of the dry or rainy. On the ground, found high levels of phosphorus in both samples collected in the batch 01, as the lot 02. The pH levels found in samples of soil, the soil can be classified as neutral and moderate alkalinity. The high infiltration rate obtained in the tests performed in lots 01 and 02 indicated the high permeability of soil at these points

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The Serido is a region of northeastern Brazil highlighted by its problems related to water scarcity because of its semi-arid region, large rates of evaporation and rainfall irregular and scarce. Thus, the underground dams, become a strategically important resource with a simple and inexpensive technique for storage of water. They act in a positive way in the development of inland cities that suffer from drought, because in addition to exercise a great improvement in the social role of these families, can enjoy the type of soil (silt) and provides water for both irrigation and for human consumption throughout the year. Is therefore essential to its monitoring and studies to assess its effectiveness in accordance with its purposes, along with their wells Amazons, as can occur in conditions of physical degradation, chemical and microbiological appropriate, according to the Ordinance No 518/04 Ministry of Health, however, the proposed work aims to analyze the underground dams in the municipality of Sierra Negra North-RN (semi-arid region) as to their uses and their influences on the quality and quantity of water in periods of drought and rain. Analyzing monthly these parameters: determination of pH, conductivity, calcium, magnesium, sodium, potassium, chloride, sulfate, RAS (sodium adsorption ratio), turbidity, total iron, nitrite, nitrate, total dissolved solids (STD), bicarbonate (HCO3), fecal coliform and pesticides compared to the standards allowed by the Ordinance in force for quality for human consumption. While at the risk of salinity and sodicity on the model proposed by the United Salinity Laboratory (USSL). Although efficient, it was found that results varied annually on water quality which may influence their specific uses, whether or irrigation water supply in the city

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The semiarid rainfall regime is northeastern Brazil is highly variable. Climate processes associated with rainfall are complex and their effects may represent extreme situations of drought or floods, which can have adverse effects on society and the environment. The regional economy has a significant agricultural component, which is strongly influenced by weather conditions. Maximum precipitation analysis is traditionally performed using the intensity-duration-frequency (IDF) probabilistic approach. Results from such analysis are typically used in engineering projects involving hydraulic structures such as drainage network systems and road structures. On the other hand, precipitation data analysis may require the adoption of some kind of event identification criteria. The minimum inter-event duration (IMEE) is one of the most used criteria. This study aims to analyze the effect of the IMEE on the obtained rain event properties. For this purpose, a nine-year precipitation time series (2002- 2011) was used. This data was obtained from an automatic raingauge station, installed in an environmentally protected area, Ecological Seridó Station. The results showed that adopted IMEE values has an important effect on the number of events, duration, event height, mean rainfall rate and mean inter-event duration. Furthermore, a higher occurrence of extreme events was observed for small IMEE values. Most events showed average rainfall intensity higher than 2 mm.h-1 regardless of IMEE. The storm coefficient of advance was, in most cases, within the first quartile of the event, regardless of the IMEE value. Time series analysis using partial time series made it possible to adjust the IDF equations to local characteristics

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The present study investigates how the inter-relationship of the content of polynomial equations works with structured activities and with the history of mathematics through a sequence of activities presented in an e-book, so that the result of this research will proceed will result in a didactic and pedagogic proposal for the teaching of polynomial equations in a historical approach via the reported e-book. Therefore, we have considered in theoretical and methodological assumptions of the History of Mathematics, in structured activities and new technologies with an emphasis on e-book tool. We used as a methodological approach the qualitative research, as our research object adjusts to the objectives of this research mode. As methodological instruments, we used the e-book as a synthesis tool of the sequence of activities to be evaluated, while the questionnaires, semi-structured interviews and participant observation were designed to register and analyze the evaluation made by the research, participants in the structured activities. The processing and analysis of data collected though the questionnaires were organized, classified and quantified in summary tables to facilitate visualization, interpretation, understanding, and analysis of these data. As for participant observation was used to contribute to the qualitative analysis of the quantified data. The interviews were synthetically transcribed and qualitatively analyzed. The analysis ratified our research objectives and contributed to improve, approve and indicate the use of e-book for the teaching of polynomial equations. Thus, we consider that this educational product will bring significant contributions to the teaching of mathematical content, in Basic Education