938 resultados para Interações eletro-fracas


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Os nascimentos ocorridos em uma população consistem em informação de grande valia para diversos estudos e planejamento de políticas públicas. O Sistema de informações sobre Nascidos Vivos (SINASC) representa uma promissora fonte de informação sobre o tema, uma vez que coleta continuamente e no âmbito municipal, dados sobre nascimentos. Tendo em vista a necessidade de avaliação contínua do SINASC e o panorama do declínio da fecundidade no Nordeste, objetivou-se avaliar a qualidade das informações provenientes do SINASC para o Nordeste, estados e microrregiões, nos anos 2000 e 2010, utilizando o Censo Demográfico como informação de referência, avaliando a cobertura do SINASC e identificando níveis e padrões de fecundidade. Pretendeu-se ainda verificar a relação entre os níveis de fecundidade, o grau de cobertura do SINASC e as condições socioeconômicas das microrregiões sintetizadas pelo Índice Social de Desenvolvimento Municipal (ISDM), utilizando-se a análise de cluster, associada à análise de variância (ANOVA) e o teste de Tukey. Por último, analisou-se a incompletude no preenchimento dos campos da Declaração de Nascido Vivo (DNV). De acordo com os resultados, observou-se que houve ampliação da qualidade das informações do SINASC no período estudado, resultando em uma maior aproximação das TFTs oriundas das duas fontes de dados consideradas no estudo. Maranhão e Paraíba foram os estados com maiores ganhos em cobertura das TFTs no período, e os estados do Rio Grande do Norte e Sergipe revelaram um grau de cobertura ligeiramente inferior em 2010 frente aos resultados de 2000, bem como ainda persistem várias microrregiões com TFTs oriundas do SINASC bem abaixo daquelas estimadas pelo Censo. Na verificação da associação entre o ISDM, TFTs e cobertura, a análise de cluster resultou em três agrupamentos, GrISDM A com melhores coberturas, ISDM e mais baixas TFT; GrISDM B , intermediário e GrISDM C com piores coberturas, ISDM e TFT mais altas. Notou-se a evolução das condições socioeconômicas no Nordeste, tendo o GrISDM A passado de 8% do total de microrregiões em 2000 para 37% em 2010. Reiterou-se ainda que quanto melhores as condições socioeconômicas de uma população, menores são as TFTs e melhores as coberturas do SINASC. A análise de variância apontou interações significativas entre o ano estudado versus ISDM (p-valor < 0,016) e o ano versus fonte de informação (p-valor < 0,020), e o teste Tukey apontou que não houve similaridade entre as médias das TFT das fontes Censo versus SINASC no período, fato que aponta para a captação ainda deficiente do SINASC nas microrregiões. O resultado da análise de variância da cobertura do SINASC em relação ao Censo apresentou uma interação significativa entre as variáveis UF versus Ano (p-valor < 0,0001), causada pelos estados que apresentaram queda de cobertura entre 2000 e 2010. Quanto à incompletude dos itens da DNV, evidenciou-se uma melhor coleta no período, embora alguns itens ainda careçam de atenção, como o apgar no 1º e 5º minuto e ocupação da mãe, sendo esta a que apresenta maiores percentuais de informações ignoradas. Destaca-se a possibilidade de preenchimento inconsistente nas variáveis referentes ao histórico de gestações anteriores, com o uso da informação zero inserida no lugar da informação ignorado . Concluiu-se que o SINASC é uma importante base de dados sobre nascimentos e que dispõe de dados confiáveis para o acompanhamento dos nascimentos e de seu panorama epidemiológico no Nordeste brasileiro, embora para alguns estados, assim como para algumas microrregiões, ainda faz-se necessária a ampliação da cobertura do Sistema. As informações constantes na DNV podem servir como embasamento para diversos estudos sobre as condições epidemiológicas dos nascituros e das suas mães, e dos indicadores baseados as informações dos nascimentos

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Um experimento foi realizado com o objetivo de avaliar os parâmetros ruminais, a produção de ácidos graxos voláteis e a degradabilidade in situ em tourinhos Santa Gertrudes canulados no rúmen alimentados com dietas compostas de feno de capim-marandu e concentrado. Empregou-se o delineamento em quadrado latino 4 ´ 4, no qual os tratamentos foram compostos dos concentrados, ajustados para ganho de peso corporal (GPC) diário de 0,5 e 1 kg/animal e potencial de fermentação microbiana (y) de 9,5 e 11 g de proteína bruta microbiana/MJ energia metabolizável fermentável. Não foram encontradas interações significativas nem diferenças entre as dietas para pH, concentração molar dos ácidos acético e butírico e proporção molar dos ácidos acético, propiônico e butírico e relação acético:propiônico. Os teores de amônia diferiram entre os potenciais de fermentação microbiana, 14,67 e 20,83 mg/100 mL para baixo e alto, respectivamente, e a concentração molar de ácido propiônico foi diferente entre os potenciais de ganho de peso, 7,62 e 8,94 mM, respectivamente, para baixo e alto ganho de peso. Não foram detectadas diferenças entre dietas para as degradabilidades das frações do feno de capim-marandu e da soja em grão. Houve diferença no parâmetro b e na degradabilidade efetiva a 5%/hora da proteína bruta para os potencias de GPC do milho em grão moído. Para o farelo de soja, ocorreu interação significativa entre os potencias de GPC e de fermentação microbiana para alguns dos parâmetros da MS e PB, o mesmo observado para o farelo de algodão. As diferenças encontradas não justificaram o balanceamento dos concentrados para os diferentes potenciais de produção avaliados.

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The food chain theory predict that presence of omnivory prevent the trophic cascade and could be a strong stabilizing factor over resource and consumer community dynamics, and that the nutrient enrichment destabilize populations dynamics. Most of the freshwater tropical reservoirs are eutrophic, and strategies that seek improve the water quality through the control of phytoplankton biomass and nutrient input, become essential for the improvement and preservation of water quality. The aim of this study was test the zooplanktivory (when larvae) and omnivory (when young and adult) effects of Nile Tilapia over the structure and dynamics of plankton communities, in addition or absence of nutrients enrichment. For this, one field experiment was performed with a factorial design 2x3 resulting in six treatments: control, without fish and nutrient (C); with omnivorous fish (O); with zooplanktivorous fish (Z); without fish and with enrichment of nutrients (NP); with omnivorous fish and nutrients (ONP); and, with zooplanktivorous fish and nutrients (ZNP). The two planktivory types reduced the zooplankton biomass and increased the phytoplankton biomass, but the omnivory of filter-feeding fish attenuated the trophic cascade magnitude. The fertilization by nutrients increases the nutrient concentrations in water and the phytoplankton biomass, but the effect on zooplankton is dependent of the trophic structure. In a general way, the effects of the fish and nutrient addition were addictive, but significant interactions among those factors were observed in the answer of some zooplankton groups. The effects of omnivorous fish over the temporal variability of phytoplankton and zooplankton biomass were very variable, the increase or reduce in variability of the plankton depending of the level of nutrients and of the analyzed variable. With base in this study, we conclude that the planktivory type exercised by the fish and the concentrations of nutrients in the water affects the force of pelagic trophic cascades and probably the success of biomanipulation programs for the handling of water quality in lakes and tropical reservoirs

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The omnivorous filter-feeding fish, Nile tilapia (Oreochromis niloticus), can have negative effects on water quality enhancing the eutrophication process. These effects depend on the nutrient enrichment level in the water. We carried out a mesocosm experiment for five weeks in a tropical man-made lake in Brazil to test ifthe effects of tilapias depend on of the level of nutrient enrichment. The experiment lasted for 5 weeks and a factorial 2x5 experimental design was used where the presence and absence of tilapias were manipulated in combination to 5 different levels of nutrient load in a total of 10 treatments. A two way repeated measure ANOVA was performed to evaluate the effects of time (t), tilapia (F), nutrients (NP) and the interactions among these factors on: chlorophyll a, water transparency, total phosphorous, total nitrogen, N:P ratio, zooplankton biomass and phytoplankton biovolume. The tilapia effect was evident, but nutrient enrichment didn t have any effect on the variables analyzed. Tilapia decreased the water transparency, total zooplankton biomass, calanoid copepod biomass, nauplii copepod biomass and cladocerans biomass. On the other hand, tilapia had no effect on phytoplankton biovolume. This lack of effect on phytoplankton is probably due to tilapia grazing that may counteract the positive effect of tilapia on phytoplankton via trophic cascades and nutrient recycling. Hence, a reduction in tilapia stock would not be an effective way to reduce phytoplankton biomass and improve water quality

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The Nile tilapia, Oreochromis niloticus, is an important omnivorous fish in the reservoirs of the semi-arid region of Brazil. Throughout its growth tilapia s feeding behavior changes from a visual predator of zooplankton to a filter-feeder, collecting suspended particulate matter, including planktonic organisms, through pumping. This feature results in different impacts of tilapia on plankton community as the fish grows. Aiming to quantify the functional response of different sizes of Nile tilapia on zooplankton experiments in microcosms scale in the laboratory and in mesocosm scale in the field were carried out. The data were fitted to four different models of functional response. The best fits were obtained for nonlinear models in laboratory experiments. While the experiments in mesocosms were the best settings for responses of type I (juvenile and adult tilapia) and type III (fry). The Manly's alpha index was used to evaluate the feeding selectivity of tilapia on the three main groups of the zooplankton in the experiments in mesocosms. The results show that: (i) rotifers were the preferred prey of fingerlings,(ii) copepods were rejected by fry and juvenile tilapia and (iii) adult fish fed non-selectively on copepods, cladocerans and rotifers. The functional response models obtained in this research can be applied to population models and help in modeling the dynamics of interactions between Nile tilapia and the planktonic communities in the reservoirs of the semi-arid

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Muitos países subdesenvolvidos são caracterizados por uma significativa diversidade sociocultural e por uma acentuada pobreza em grande parte da população, que fazem uso da caça de animais como uma fonte alternativa de alimento e para outros fins. O estudo objetivou investigar se a distância das populações humanas da zona rural em relação à zona urbana e fatores socioeconômicos podem ser preditores de um maior conhecimento sobre as espécies da fauna utilizadas. Além disso, o estudo objetivou também testar uma ferramenta capaz de gerar uma lista da fauna prioritária para a conservação local a partir do conhecimento local. Os dados foram coletados por meio de 30 entrevistas utilizando formulários semi-estruturados em quatro comunidades rurais no município de Pedro Avelino, RN. Foram calculados o fator de consenso dos informantes (ICF), a importância relativa (IR) e o nível de fidelidade (FL). Adicionalmente, foi calculado o índice de Shannon-Wiener para as categorias de uso: estimação, alimentar, medicinal e para a multiplicidade de uso por informante. Os entrevistados reconhecem 83 espécies pertencentes a 45 famílias de animais. As espécies citadas pertencem a seis grandes grupos taxonômicos: aves, mamíferos, répteis, anfíbios, peixes e insetos. O conhecimento sobre a utilização de animais para as categorias de uso definidas neste trabalho não mostrou relação significativa com os fatores socioeconômicos e nem com a distância das comunidades da zona rural para a zona urbana de Pedro Avelino. Os resultados sugerem, portanto, que a pobreza nivela o conhecimento sobre o uso da fauna independente da distância que as comunidades encontram-se da zona urbana. As listas geradas permitirão direcionar estudos ecológicos mais aprofundados visando à conservação das espécies do bioma Caatinga. Desta forma, é importante considerar as interações existentes entre as pessoas e os animais para melhor entender a dinâmica de utilização e fornecer, assim, subsídios para a conservação das espécies.

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The use of animals is a common activity but it can be really variable between human populations. This work analyzed the knowledge about useful animal species between human communities in Caatinga and Atlantic Forest considering the influence of socioeconomics and environmental factors on the species selection. Forty people were interviewed in Caraúbas community (Atlantic Forest) and thirty were interviewed in Barrocas community (Caatinga). A total of 193 animals were cited. The communities showed a low degree of similarity (20%) and the general diversity of mentioned species was significantly bigger in Caraúbas. Men cited a diversity of species greater than women for food category in Caraúbas and pet category in Caraúbas and Barrocas. Women cited greater species diversity for medicinal use in Caraúbas. In general, in both communities, the age group >60 years showed a greater knowledge than the others. The multiple regression analysis showed the age as the only socioeconomic factor which influenced significantly the knowledge about animals for the food category in both communities. Considering the richness of known species, there were differences only between gender for sum of uses and food category in Caraúbas and for the pet category in Barrocas with men showing a greater knowledge than women. The results showed that local environmental differences are fundamental at the species selection but they also showed that within communities there are other factors like gender and age that tend to influence the knowledge about species. It is important to consider cultural, economic, social and environmental factors to understand better the interactions between people and animals so that this information can be used to facilitate the implementation of conservation measures

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Protozoa may be an important alternative food source for Calanoida copepods in these environments. Aiming to quantify the feeding preferences of N. cearensis by ciliates in the presence of cyanobacteria, in vitro experiments were conducted, using mixed cultures in different concentrations of total food for copepod. Two ciliates species (Paramecium sp. and Cyclidium sp.) and a cyanobacteria toxic strain (Microcystis aeruginosa) were offered as food. Previous experiments were done to identify the copepod s maximum ingestion rate through the use of a type II functional response model when each prey is offered separately. High maximum ingestion rate were found when those protists were offered as prey. N. cearensis showed significant preference for protozoal prey over the cyanobacterium tested both in low (corresponding 95.15% of the diet) and in high food concentration treatments (about 91.56% of the diet), preferring the bigger ciliate in lower concentrations (67.52% of the diet). The meaningful involvement of heterotrophic organisms in the zooplankton diet emphasis the microbial loop participation in the energy transition from copepods to higher trophic levels. This data contributes to understand the stability of existing trophic interactions in reservoirs subjected to eutrophication and assists trophic cascade studies in these environments

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The soil macrofauna is influenced to several biotic and abiotic environmental factors, from changes in the physical environment to a variety of interactions among the species involved, affecting the patterns of biodiversity of soil fauna. The power and specificity of the mechanisms that act on soil organisms vary greatly depending on environmental conditions at different scales of space and time. The Caatinga has great spatial heterogeneity of vegetation, climate and soil, so the soil macrofauna would follow this local spatial variation in the environment? This study aimed to investigate the effects of local environmental variables on biological parameters (taxa richness, total abundance and biomass) of soil macrofauna in a fragment of caatinga in João Câmara, Rio Grande Norte, Northeast Brazil. The study was conducted in the Cauaçu farm, where a grid of 2000m x 500m was drawn, and later, 30 sampling points were randomly selected. The methodology used to collect the macrofauna was the TSBF method. We tested the effects of 10 environmental variables on macrofauna across the plots and across the layers of soil. The hypothesis that macrofauna soil responds to changes in the environment was not supported throughout the plots, but was confirmed to soil layers. The soil macrofauna shows a pattern of concentration in the surface layer and decreases considerably in the deeper layers. This pattern had significant and positive relationship with the aerial plant biomass and fine root stock. The aerial plant biomass releases plant necromass that accumulates in the surface layer, providing an important source of resource and shelter for soil macrofauna, explaining their greater abundance in this layer. The roots are used as a means for the arrival of nutrients to the soil from the primary production, thus a greater amount of root conditions higher food intake for macrofauna, especially the herbivores

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Ethnobiology studies Local Ecological Knowledge (LEK) as well as the use and management of natural resources by local communities in order to understand how the environment is perceived, known and classified by human groups. In fishing communities, LEK adds empirical information about the biology of aquatic species and complements scientific findings, especially when it is difficult to obtain factual information during studies on cetaceans, whose behavior is essentially underwater. Cetaceans (whales and dolphins) are constantly threatened by human activities, especially by accidental capture of small coastal species, as in the case of the estuarine dolphin (Sotalia guianensis), object of this study. Ethnobiological researches in fishing communities are of great importance and can clarify aspects of the biology and conservation of this species. Although extensively studied throughout its distribution range, there are still gaps in the knowledge about S. guianensis. Therefore, fishers local ecological knowledge becomes an additional tool to get and confirm information about S. guianensis. This study evaluated the LEK of artisanal fishers who are daily exposed to local population of S. guianensis, through the use of semistructured interviews (N=116). The interviewed fishers were asked about the biology and popular classification of S. guianensis and about possible interactions between this dolphin and them. The studied communities were located in Tibau do Sul (n=39), Pipa (n=36) and Baía Formosa (n=41), all on the south coast of Rio Grande do Norte, Brazil. The study was based on the assumption that differences in fishers LEK among those communities would be caused by both the variety of fishing environments (lagoon/estuary and ocean) and the intensity of tourism activities. Fishers knowledge is expressive and differed among the studied communities depending on the topic investigated. Fishers correctly reported the habitat, distribution, seasonality and behavioral particularities of S. guianensis. Tourism mainly affected the naming of the species. The study results also suggest that marine fishers have greater knowledge about the species than the estuarine/lagoon ones. Local populations accumulate empirical knowledge according to their environment. Hence, it is important to take into account both empirical knowledge and popular participation in management systems, in order to maintain information sharing among communities

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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This study aimed to compare the development of crab and tree communities of two restored mangrove areas, one planted with Rhizophora mangle and the other naturally recovered, and also to compare the predation of Grapsid crab Goniopsis cruentata and the Ocypodid Ucides cordatus over the propagules of three mangrove trees: Rhizophora mangle, Avicennia schaueriana e Laguncularia racemosa. Specifically, we tested the hypothesis that Goniopsis predation is more important that Ucides predation, and that these consumers have antagonist effects over propagule consumption. In each area, 10 quadrates were selected at random to analyze tree richness, diameter, height, tree biomass and crab richness and density five years after restoration experiment start. Results show that tree height, biomass and crab density were significantly higher in artificially restored area. No significant differences were observed in crab species richness between areas, but higher tree richness was observed in self-recovered area. Results suggest that planting propagules of Rhizophora can significantly increase tree recovering if the aim was increase tree biomass and crab density, which can accelerate return of ecological functionality. Goniopsis is a more important propagule predator than Ucides both in natural and restored areas. The effects of Goniopis were higher in absence of Ucides, due to negative interactions among these two predator species. The preference of Goniopsis by Avicennia and Laguncularia can favor the dominance of Rhizophora observed in Neotropical mangroves. This study suggests that propagule predation by Goniopsis should be controlled in restoration programs, if dominance of Rhizophora is undesirable respect to more rich tree communities

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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Understand the origin, maintenance and the mechanisms that operate in the current biodiversity is the major goal of ecology. Species ecology can be influenced by different factors at different scales. There are three approaches about the ecological differences between species: the first brings that differences result from current processes on niche characteristics (e.g. diet, time, space); the second that species differences are explained by random patterns of speciation, extinction and dispersion, the third that historical events explain the formation and composition of species in communities. This study aims to evaluate the influence of phylogenetic relationships in determining ecological characteristics in amphibians (globally) and test with that, if ecological differences between species of frogs are the result of ancient pre-existing differences or as result of current interactions. Another objective of this study is to verify if ecological, historical or current characteristics determine the size of species geographical distribution. The diet data for analysis of trophic ecology were collected from published literature. We performed a non-parametric MANOVA to test the existence of phylogenetic effects in diet shifts on frogs history. Thus, it is expected to know the main factors that allow the coexistence of anuran species. We performed a phylogenetic regression to analyze if niche breadth, body size and evolutionary age variables determine the size of the geographical distribution of amphibians in the Amazon. In the present study, new contributions to knowledge of major ecological patterns of anurans are discussed under a phylogenetic perspective

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Broadly anchored on Institutionalist literature this dissertation seeks to answer: Why rural credit granted to farming families in Rio Grande do Norte, Pronaf group B, has shown positive results in some territories while in others the same results are insatisfactory? Considering formal rules are the same, then why such results are so distinguished? This research supports the fact that these results are a direct consequence of the quality of institutions defined as longstanding social rules established and built in social interactions. For institutions one understands; organizational structures, formal and non-formal rules, social trust, thinking behaviors and its evolution as well as routines. Using Pronaf Rural Credit as a background this study measures and compares results obtained in the rural areas of Seridó, Sertão do Apodi, Mato Grande, Assú-Mossoró, Trairi, Potengi and Alto Oeste. The dimensions of measurement considered were: economics, social and guarantee of transparency. The study considers a sample of 402 Group B farming families. It also elaborates a socio-economic profile of these families in the considered areas and underlines the main causes for defaulted loans, difficulties to improve family income and results of access to Pronaf B credit line, as well as it proposes solutions to surpass obstacles to improve the efficiency of this credit line