997 resultados para Interchange nets


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The Tatui river hydrographic basin locates in low Sorocaba river basin in São Paulo state, Brazil. A relatively high diversity of fish species was noticed at that place, whose habitats are also presumed to be diversified. The Tatui river is an important tributary of Sorocaba river, with great number of smaller streams and marginal lagoons. Fishes were collected using gill-nets, purse seines, sieves and traps, line and hook, every month during one year (from May 2009 to April 2010). Fish species were 51, including seven orders and 18 families. Characiformes and Siluriformes were the most represented with respectively 26 and 14 species.

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A study of ticks associated with wild animals was carried out from September 1996 to April 1998 at the Fazenda Alegria (21,000 ha), in the Nhecolândia Pantanal, State of Mato Grosso do Sul, Brazil, a sunken plain bordering the upper Paraguay river, located 19 × 08′S; 56 × 46′W. A total of 81 wild animals (13 species, 6 orders) were captured with the aid of nets, and ticks were found on 63 (78%). Tick species identified included Boophilus microplus (Canestrini), Amblyomma cajennense (F.), A. parvum (Aragão), A. pseudo-concolor (Aragão), A. scalpturatum (Neumann), A. nodosum (Neumann), A. ovale (Koch), and A. tigrinum (Koch). Dragging from grasslands (campos) yielded negative results compared to the high concentration of ticks, mainly nymphs, that were collected from leaves in the forests (capão). Predominance of immature instars (Amblyomma genera) was observed in the end of winter (August-September). Ticks were associated mainly with coatis, deer (Mazama gouazoubira) and anteater, and these animals may play a role in the epidemiology of tick-transmitted pathogens in the Pantanal if one considers their coexistence with local domestic animals.

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A survey was carried out on the fish species in the Sorocaba River basin, the main tributary of the left margin of the Tietê River, located in the State of São Paulo, Brazil. The species were collected with gill nets. After identification of the specimens, their relative abundance, weight and standard length were determined. Up to the present moment there are not any studies that focus this subject in this hydrographic basin. Fifty-three species, distributed in eighteen families and six orders were collected. Characiformes were represented by twenty-eight species, Siluriformes by seventeen species, the Gymnotiformes by three species, Perciformes and Cyprinodontiformes by two species, and the Synbranchiformes by one species. Among the collected species there were two exotic. The most abundant species were Astyanax fasciatus and Hypostomus ancistroides. In relation to total weight the most representative species were Hoplias malabaricus and Hypostomus ancistroides. Cyprinus carpio, Prochilodus lineatus, Schizodon nasutus and Hoplias malabaricus were the most representative species in relation to average weight. Largest standard length were recorded for Sternopygus macrurus, Steindachnerina insculpta, Eigenmannia off. virescens and Cyprinus carpio.

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The ichthyofauna of ribeirão Grande microbasin that runs through one of the few remaining fragments of Atlantic Forest (in Mantiqueira mountain range, Valley of Paraíba) was studied. Fish samples were obtained with an electric fishing powered by a maximum capacity generator of 155 V and 60-Hz alterning current, gill-nets and traps. In three collecting days, during July/2001, October/2001, January/2002 and April/2002, 2865 fishes were sampled. These fishes belonged to 12 families, 23 genera and 37 species. The species were more abundant between the piedmont and the plain of the Valley of Paraíba. The Characidium, Trichomycterus genera and the Imparfinis minutus species presented only one ovary or testis and no swim bladder. The ecological significance of morphological features in stream mountain fishes was used to predict the niche adaptation for those conditions, towards K-strategy.

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We present the results of the first bat inventory at the 'Serra das Araras' Ecological Station, MT, in the northwestern portion of the Cerrado domain. We captured bats using the traditional ground-level mist netting and, occasionally, high nets placed 3 m above the ground, and hand nets for hoosting bats. We recorded 23 species distributed in six families (Emballonuridae, Noctilionidae, Mormoopidae, Phyllostomidae, Molossidae, and Vespertilionidae), including Artibeus gnomus and A. anderseni, which had never been recorded in the Cerrado domain. © 2004 Instituto de Ciências Biológicas - UFMG.

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We have recently proposed an extension to Petri nets in order to be able to directly deal with all aspects of embedded digital systems. This extension is meant to be used as an internal model of our co-design environment. After analyzing relevant related work, and presenting a short introduction to our extension as a background material, we describe the details of the timing model we use in our approach, which is mainly based in Merlin's time model. We conclude the paper by discussing an example of its usage. © 2004 IEEE.

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Aiming to describe the patterns of the fish assemblages organization in streams of the Iguatemi River basin we sampled streams with seine nets and sieves from November/1999 to August/2000. We collected 567 individuals distributed in 24 species. We detected statistically significant influence of the streams characteristics upon species diversity. The species composition was hardly explained by the physical and chemical characteristics of the streams. Then we detected significant influence of the fish ecomorphology in the species occurrence (Mantel r = -0.34; P = 0.04), but not in the distribution of its abundance (Mantel r = -0.21; P = 0.07). We verified through the species co-occurrence index (C-score) that its composition in the studied streams is stochastic.

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The main objective involved with this paper consists of presenting the results obtained from the application of artificial neural networks and statistical tools in the automatic identification and classification process of faults in electric power distribution systems. The developed techniques to treat the proposed problem have used, in an integrated way, several approaches that can contribute to the successful detection process of faults, aiming that it is carried out in a reliable and safe way. The compilations of the results obtained from practical experiments accomplished in a pilot radial distribution feeder have demonstrated that the developed techniques provide accurate results, identifying and classifying efficiently the several occurrences of faults observed in the feeder.

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Nowadays there is great interest in damage identification using non destructive tests. Predictive maintenance is one of the most important techniques that are based on analysis of vibrations and it consists basically of monitoring the condition of structures or machines. A complete procedure should be able to detect the damage, to foresee the probable time of occurrence and to diagnosis the type of fault in order to plan the maintenance operation in a convenient form and occasion. In practical problems, it is frequent the necessity of getting the solution of non linear equations. These processes have been studied for a long time due to its great utility. Among the methods, there are different approaches, as for instance numerical methods (classic), intelligent methods (artificial neural networks), evolutions methods (genetic algorithms), and others. The characterization of damages, for better agreement, can be classified by levels. A new one uses seven levels of classification: detect the existence of the damage; detect and locate the damage; detect, locate and quantify the damages; predict the equipment's working life; auto-diagnoses; control for auto structural repair; and system of simultaneous control and monitoring. The neural networks are computational models or systems for information processing that, in a general way, can be thought as a device black box that accepts an input and produces an output. Artificial neural nets (ANN) are based on the biological neural nets and possess habilities for identification of functions and classification of standards. In this paper a methodology for structural damages location is presented. This procedure can be divided on two phases. The first one uses norms of systems to localize the damage positions. The second one uses ANN to quantify the severity of the damage. The paper concludes with a numerical application in a beam like structure with five cases of structural damages with different levels of severities. The results show the applicability of the presented methodology. A great advantage is the possibility of to apply this approach for identification of simultaneous damages.

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The objective of this study was to investigate the spatial and temporal distribution of Libinia spinosa H. MILNE EDWARDS 1834 on unconsolidated sublittoral bottoms in two regions off the northern coast of the state of São Paulo, and to analyze the influence of environmental factors on the occurrence of this species and observe the recruitment pattern of its young. Crabs were collected monthly (July 2001 through June 2003) at depths of 5, 10, 15, 20, 25, 30 and 35 In, from a fishing boat equipped with two double-rig nets. Samples of water and sediment were collected for analysis of environmental factors. A total of 2112 spider crabs was obtained (701 juveniles and 1411 adults). The highest abundance was observed at depths of 20 and 25 m, in both regions. These localities were characterized by substrate composed of very fine sand and silt-clay. In regard to the temporal distribution, juveniles and adults predominated in the summer and winter months respectively. From these results, one can infer that the distribution of L. spinosa is related to environmental factors favorable for its life cycle; sediment type is the factor which most strongly determines its presence. © E. Schweizerbart'sche Verlagsbuchhandlung (Nägele u. Obermiller), 2007.

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In this work are presented data for mean abundance, prevalence and mean intensity of infection in 34 specimens of Pseudoplatystoma fasciatum, commonly called cacharas. Fish were captured using nets in the Aquidauana river during March, September and November 2003, October 2004 and October 2005. All analyzed fish were infected. Nineteen species of parasites were collected - seven of them were proteocephalid cestodes, three monogeneans, one species of digeneans, three nematodes, one acanthocephalan, one crustacean, one pentastomid and two species of myxosporeans. The first records of Harriscolex kaparari and Megathylacus travassosi in P. fasciatum in the Aquidauana river were observed. Monogeneans featured the highest prevalence (100%), followed by cestodes (91.18%) and nematodes (58.82%).

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The short-distance part of the low energy interaction of D-mesons and nucleons is investigated in the context of a quark model. The quark model is based on Coulomb gauge QCD. The model contains a confining Coulomb potential and a transverse hyperfine interaction consistent with a finite gluon propagator in the infrared. The basic mechanism for the short-distance interaction between the D-mesons and nucleons is quark interchange. Using Resonating GroupMethod techniques an effective potential for the interaction between nucleons and D mesons can be obtained and used in a Lippmann-Schwinger equation to obtain differential cross-sections and phase shifts.

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Includes bibliography