132 research outputs found

    Estudo de um algoritmo de mineração de dados aplicado à avaliação de curvas de consumo de energia elétrica

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    Nowadays, the quantity of inherent information to our environment is huge. For treat these information appeared an area called Data Mining. Inside of this area, there are some algorithms to carry out the knowledge discovery in Data Bases. Some examples of algorithms can be mentioned, such as: Neural Networks, Fuzzy Logic, Genetic Algorithm, Bayesian Algorithm, and Induction Tree. In this work topics related with Data Mining were studied, with the purpose of apply in problems related with Electrical Engineering. The Naive Bayes algorithm was chosen with objective of recognize electrical energy consumption patterns, as an alternative to Artificial Neural Networks that are remembered in pattern recognition problems. Initially, some concepts of statistics were analyzed, and subsequently the concepts of the algorithm Naive Bayes are presented. The original algorithm was modified with the purpose of recognize load curves of industrial, commercial, residential consumers in Electrical Power Systems. A computational package, called Weka, has been used. This package implemented was implemented in Java and has several data mining algorithms.No dias atuais, a quantidade de informações inerentes ao nosso meio é enorme. Para tratar estas informações surgiu uma área conhecida como mineração de dados – “Data Mining”. Dentro desta área, existem diversos algoritmos para realizar o processo de descoberta do conhecimento em banco de dados. Pode-se citar como exemplos de algoritmos: Redes Neurais Artificiais, Lógica Fuzzy, Algoritmos Genéticos, Algoritmos Bayesianos, Árvores de Indução entre outros. Neste trabalho foram estudados tópicos relacionados com Mineração de Dados, com a finalidade de aplicá-los na solução de problemas relacionados com a Engenharia Elétrica. Escolheu-se o algoritmo “Naive Bayes”, com objetivo de reconhecer padrões de consumo de energia elétrica, assim buscando uma alternativa às Redes Neurais Artificiais – RNA que são lembradas quando se trata de reconhecimento de padrões. Para facilitar o entendimento do algoritmo escolhido, alguns conceitos de estatística foram analisados, e posteriormente são apresentados os conceitos do algoritmo “Naive Bayes”. Com a finalidade de elucidar uma aplicação do “Naive Bayes” foi realizado um estudo de caso, onde o algoritmo foi modificado com a finalidade de reconhecer curvas de carga ou curvas de consumo de consumidores residenciais, comerciais e industriais presentes no Setor Elétrico de Potência. Para viabilizar a implementação desse estudo de caso, foi utilizado o pacote computacional, chamado Weka, o qual possui vários algoritmos de Mineração de Dados implementados em Java

    A pesca e o conhecimento ecológico local dos pescadores de acará-disco (Symphysodon aequifasciatus, Pellegrin 1904: Cichlidae) na Reserva de Desenvolvimento Sustentável Piagaçu-Purus, baixo rio Purus, Brasil

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    The discus fish (Symphysodon aequifasciatus, Pellegrin 1904), an endemic cichlid from the Amazon basin, is one of the most popular ornamental fish species in the world. However, there is little information available in the scientific literature on the exploitation of this species in its natural habitat. In this article we describe the small-scale discus fisheries activity in the Reserva de Desenvolvimento Sustentável Piagaçu-Purus (RDS-PP), lower Purus River, Brazil, based on field observations, structured and open-ended interviews with fishermen and local inhabitants. Discus fishery is seasonal, occurring mainly in the dry season. Local fishermen use fish attractors to catch the species and underwater hearing methods to estimate its presence and abundance. Discus fishes are locally kept in wooden storage tanks and carried in plastic containers for distribution in regional markets by means of fishing boats, commercial boat lines or rafts. Discuses are sold in Manaus, State of Amazonas, to export companies specialized in ornamental fish trade. We describe the local ecological knowledge on the discus among fishermen living within the RDS-PP and discuss its importance for ornamental fishery management in that protected area

    Two new species of Apistogramma Regan (Teleostei: Cichlidae) from the rio trombetas, Pará State, Brazil.

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    Apistogramma angayuara is described from the rio Trombetas close to the cachoeira Vira Mundo where it is found in association with rapids. It is assigned to the A. pertensis species group, distinguished by the following characters in combination: three prominent stripes composed of dark spots along the sides of the abdomen, 2 vs. 3 postlachrymal infraorbital pores, 5 vs. 4 dentary pores, low dorsal fin in adult males, and presence of a caudal spot. It is the smallest species of Apistogramma reported so far, with the largest male 24.7 mm SL and the largest female 22.7 mm SL, and the first cichlid species found with a significant proportion of rhizopods in the stomach content. Apistogramma salpinction is described from lentic habitats at the margin of road BR-163, circa 70 km from Cachoeira Porteira village, in a swamp most probably connected to the igarapé Caxipacoré. It is compared to members of the Apistogramma cacatuoides group with which it shares prolonged anterior dorsal fin lappets and marginal caudal fin streamers in adult males. It is distinguished from all other species of Apistogramma by the color pattern which includes a lateral band and abdominal stripes that become darker and have much lighter interspaces on the caudal peduncle, and a caudal spot that is divided into elongated blotches continuing the lateral band and upper two abdominal stripes, respectively

    Two new species of Apistogramma Regan (Teleostei: Cichlidae) from the rio Trombetas, Pará State, Brazil

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    Apistogramma angayuara is described from the rio Trombetas close to the cachoeira Vira Mundo where it is found in association with rapids. It is assigned to the A. pertensis species group, distinguished by the following characters in combination: three prominent stripes composed of dark spots along the sides of the abdomen, 2 vs. 3 postlachrymal infraorbital pores, 5 vs. 4 dentary pores, low dorsal fin in adult males, and presence of a caudal spot. It is the smallest species of Apistogramma reported so far, with the largest male 24.7 mm SL and the largest female 22.7 mm SL, and the first cichlid species found with a significant proportion of rhizopods in the stomach content. Apistogramma salpinction is described from lentic habitats at the margin of road BR-163, circa 70 km from Cachoeira Porteira village, in a swamp most probably connected to the igarapé Caxipacoré. It is compared to members of the Apistogramma cacatuoides group with which it shares prolonged anterior dorsal fin lappets and marginal caudal fin streamers in adult males. It is distinguished from all other species of Apistogramma by the color pattern which includes a lateral band and abdominal stripes that become darker and have much lighter interspaces on the caudal peduncle, and a caudal spot that is divided into elongated blotches continuing the lateral band and upper two abdominal stripes, respectively. Apistogramma angayuara é descrita para o rio Trombetas próximo à cachoeira Vira Mundo, onde é encontrada associada com corredeiras. É a menor espécie de Apistogramma até agora registrada, com o maior macho atingindo 24,7 mm CP, e a maior fêmea 22,7 mm CP. Trata-se do primeiro registro de uma espécie de ciclideo com grande quantidade de rizopodos em seu conteúdo estomacal. Apistogramma angayuara pertence ao grupo A. pertensis e difere das demais espécies deste grupo pela seguinte combinação de caracteres: três conspícuas séries de pontos escuros ao longo da região abdominal, 2 vs. 3 poros infra-orbitais pós-lacrimais, e 5 vs. 4 poros dentários, nadadeira dorsal baixa em machos adultos, e presença de uma mancha caudal grande. Apistogramma salpinction é descrita de habitats lênticos localizados na margem da BR-163, cerca de 70 km da vila de Cachoeira Porteira, em um alagadiço que provavelmente está conectado ao igarapé Caxipacoré, e é semelhante a membros do grupo Apistogramma cacatuoides com o qual compartilha as membranas anteriores da nadadeira dorsal prolongadas e faixas marginais na nadadeira caudal em machos adultos. Entretanto, difere pelo padrão de colorido que inclui uma faixa lateral e listras abdominais mais escuras e com interespaços mais claros no pedúnculo caudal, que se prolongam sobre a base da nadadeira caudal em uma pinta caudal dividida em manchas alongadas continuando a faixa lateral e duas listras abdominais, respectivamente

    Occurrence of eggs and larvae of migratory Chaciformes Fish in the Negro River, Amazonas, Brazil

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    The occurrence of larvae and eggs of seven species of migratory Characiformes in larvae with yolk, preflexion, and flexion stages is described for the first time in the Negro River. The possibility of these species spawning in this system is discussed.A ocorrência de ovos e larvas de sete espécies de Characiformes migradores em estágio de larval vitelino, pré-flexão e flexão, é descrita pela primeira vez para o rio Negro. É discutida a possibilidade de desova dessas espécies neste sistema pela fase de desenvolvimento ontogênico em que foram capturadas

    Patterns of energy allocation to reproduction in three Amazonian fish species

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    The study considered the influence of the hydrological cycle and gonadal development on the accumulation and use of energy in three fish species from an Amazonian flooded area. Fishes were sampled over a 24 hour period at monthly intervals between July 2004 and June 2005 using gillnets of different mesh sizes. Body cavity fat and gonadosomatic indices were determined, as well as energy content of gonads and muscles. Amongst the studied species, different means of energy allocation for reproduction were found: Acestrorhynchus falcirostris allocate energy from body cavity fat to its gonads; Pygocentrus nattereri uses mainly energy accumulated in the muscles for the process of gonadal maturation; and Hoplosternum littorale uses energy accumulated in their muscles and body cavity fat for reproductive processes. It is quite clear that the flood pulse regulates the gain and use of the energy reserves in fishes from the Amazonian floodplain. © 2010 Sociedade Brasileira de Ictiologia

    Phylogenetic community structure: Temporal variation in fish assemblage

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    Hypotheses about phylogenetic relationships among species allow inferences about the mechanisms that affect species coexistence. Nevertheless, most studies assume that phylogenetic patterns identified are stable over time. We used data on monthly samples of fish from a single lake over 10 years to show that the structure in phylogenetic assemblages varies over time and conclusions depend heavily on the time scale investigated. The data set was organized in guild structures and temporal scales (grouped at three temporal scales). Phylogenetic distance was measured as the mean pairwise distances (MPD) and as mean nearest-neighbor distance (MNTD). Both distances were based on counts of nodes. We compared the observed values of MPD and MNTD with values that were generated randomly using null model independent swap. A serial runs test was used to assess the temporal independence of indices over time. The phylogenetic pattern in the whole assemblage and the functional groups varied widely over time. Conclusions about phylogenetic clustering or dispersion depended on the temporal scales. Conclusions about the frequency with which biotic processes and environmental filters affect the local assembly do not depend only on taxonomic grouping and spatial scales. While these analyzes allow the assertion that all proposed patterns apply to the fish assemblages in the floodplain, the assessment of the relative importance of these processes, and how they vary depending on the temporal scale and functional group studied, cannot be determined with the effort commonly used. It appears that, at least in the system that we studied, the assemblages are forming and breaking continuously, resulting in various phylogeny-related structures that makes summarizing difficult. © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd

    Simultaneous abrupt shifts in hydrology and fish assemblage structure in a floodplain lake in the central Amazon

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    Combined effects of climate change and deforestation have altered precipitation patterns in the Amazon. This has led to changes in the frequency of extreme events of flood and drought in recent decades and in the magnitude of the annual flood pulse, a phenomenon that influences virtually all aspects of river-floodplain ecosystem dynamics. Analysis of long-term data revealed abrupt and synchronous changes in hydrology and fish assemblage structure of a floodplain lake near the confluence of Amazon and Negro rivers. After an intense drought in 2005, the assemblage assumed a different and fairly persistent taxonomic composition and functional structure. Declines in abundance after 2005 were more pronounced for species of all sizes having equilibrium life history strategy, large species with periodic life history strategy, and for all trophic levels except primary consumers. Our results suggest that the extreme drought triggered changes in the fish assemblage and subsequent anomalous hydrological conditions have hampered assemblage recovery. These findings stress the need to account for climatic-driven hydrological changes in conservation efforts addressing aquatic biodiversity and fishery resources in the central Amazon

    A new species of Dadayius Fukui, 1929 (Digenea: Cladorchiidae), parasite of Symphysodon aequifasciatus Pellegrin, 1904 (Perciformes: Cichlidae) from the Purus River, Amazon, Brazil

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    Summary: The present paper describes a new species of Dadayius Fukui, 1929 (Trematoda, Digenea), parasite of Symphysodon aequifasciatus Pellegrin, 1904, a freshwater fish. The fish were collected from the Purus River, Amazonas State, Brazil. This new species has a long body and, different from other species of the genus, an arch-shaped ovary and a sinuous oesophagus with an ovoid bulb. This is the first record of Dadayius in cichlid fish; to date Dadayius has only been found parasitizing characid fish. © 2011 © Versita Warsaw and Springer-Verlag Wien
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