A Study On The Flow Characteristics Influenced By Hydraulic Structure At A Channel Junction

Natural riversare consisting of various networks as junction andstreams. And sediment and erosion are occurred by specific stream condition. When flood season,large discharge flew in the river and river bed changed by high flow velocity. Especially junction area’s flow characteristics are very complex. The purpose of this study is to analyze the flow characteristics in channel junction, which are most influenced by large discharge like flooding and input water from tributary. We investigate the flow characteristics by using hydrodynamics and transport module in MIKE 3 FM. MIKE 3 FM model was helpful tool to analysis 3D hydrodynamics, erosion and sediment effect from channel bed. We analyze flow characteristics at channel junction. Also we consider hydraulic structures like a bridge pier which is influencing flow characteristics like a flow velocity, water level, erosion and scour depth in channel bed. In the model, we controlled discharge condition according to Froude Number and reflect various grain diameter size and flow ratio change in main stream and tributary. In the result, flow velocity, water level, erosion and sediment depth are analyzed. Additionally, we suggest a these result relationship with equations. This study will help the understand flow characteristics and influence of hydraulic structure in channel junction. Acknowledgments This research was supported by a grant (12-TI-C01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

Análise da proposta de reforma tributária (EC nº 42) do governo Lula

As mudanças tributárias realizadas na última década priorizaram o ajuste fiscal com uma elevação da carga de impostos que saltou de 27% do PIB, em 1994, para cerca de 36% do PIB, em 2003. Esse aumento da carga tributária esteve associado principalmente ao aumento das contribuições sociais cumulativas. Além dessa crescente cumulatividade, outras características que têm marcado o sistema tributário brasileiro são a complexidade e os conflitos federativos que alimentam uma profunda guerra fiscal entre Estados e municípios. Em abril de 2003, o Governo Lula encaminhou ao Congresso Nacional uma ampla proposta de reforma tributária, tendo como objetivos principais (i) simplificar o sistema tributário brasileiro, (ii) reduzir a cumulatividade dos tributos e (iii) acabar com a guerra fiscal. Apesar do reconhecimento generalizado de que a carga tributária brasileira é excessivamente elevada, o governo federal limitou-se a assumir o compromisso de não promover aumentos adicionais de impostos. Inserido nesse contexto, este estudo analisa (i) o quadro fiscal brasileiro, procurando identificar as reais restrições que impedem a redução da carga tributária brasileira e (ii) as medidas tributárias propostas pelo Governo Lula, destacando suas implicações sobre o desenvolvimento econômico brasileiro.

Uma análise das propostas de reforma tributária recentes

Em 1988 o Congresso Brasileiro promulgou uma nova Constituição que propiciava uma descentralização da arrecadação tributária entre os entes federativos. Apesar das profundas mudanças promovidas, a nova Constituição não foi capaz de assegurar a estabilidade macroeconômica assim como a redução das desigualdades regionais. Ao contrário, as mudanças promovidas estimularam um contínuo processo de 'remendos' legais que elevaram o 'custo Brasil' e estimularam a 'Guerra Fiscal' entre estados. O resultado foi a emergência de um sistema tributário arcaico, complexo, estruturalmente injusto e excessivamente oneroso para o contribuinte. Inserido nesse contexto, os principais objetivos deste estudo serão (i) avaliar o atual sistema tributário brasileiro que resultou da Constituição de 1988, e (ii) as principais propostas de reforma tributária que vêm sendo discutidas nos últimos anos.

O Papel das cooperativas de trabalho no contexto das transformações da sociedade brasileira: um estudo do caso no Município do Rio de Janeiro

The changes that have occurred in the Brazilian work market, mainly due to the opening of the economy in the 90th decade, have caused, as a consequence, the unemployment in the formal sector, with the reduction of posts of work in the industry and the precarization of the laborwork. In order to face these questions, it¿s necessary an analysis of the alternative measures, among them, the creation of the cooperative societies, which have increased about 90,8% in the last years. The purpose of this study is to identify and to analyze the functions of the work cooperatives, just in face of the changes of the Brazilian society. The analysis was directed towards a group of eight work cooperatives that work in lots of areas of professionals in the Municipality of Rio de Janeiro. The study reveals the existence of false work cooperatives, whose sole purpose is to intermediate the handiwork with the intention of benefiting enterprises that intend to decrease their own costs of production, just contributing for the precarization of the relations of work. The structure of the Judicial Power offers solutions that protect the workers who are exploited through fraudulent actions, by the false cooperatives, handiworkers. It can be noticed that this structure is enough to answer the challenges presented. It means that it is too bad to apprehend the revival of the work cooperativism and that it must be combated. Of course, it is maniqueist conception that distorts reality and disdains positive aspects of cooperative system. The results of the search have permitted to point out the main characteristics of the work cooperatives analyzed, the profile of the cooperative workers, and also the main obstacles to the development of the cooperative system in Brazil today . A long the analysis of tributary and labor questions and about the participation of the cooperative workers in the management of the cooperative - the most questionable points - it could be observed the development of real cooperative practices, trying to establish the differences between these and the fraudulent ones, also studied in this work. This study represents a contribution to all those who intend to study new relations of work in a critical away and from experiences in development.

Por uma reforma dos sistemas horizontal e vertical de divisão de funções do Estado

Enquanto muito se discute nos meios acadêmicos no próprio Congresso Nacional teor das reformas política, tributária previdenciária, todas elas, aliás, fundamentais ao país, esta monografia aborda outras dimensões de reforma, relacionadas organização funcional do Estado Brasileiro. Assim porque exigência de um Estado eficiente responde não somente questão de sua legitimidade, mas é, hoje, no ambiente globalizado de intensa competição de constante instabilidade, imperativo do próprio desenvolvimento de uma nação, especialmente Brasil, que deve, paralelamente, enfrentar um enorme déficit social acumulado. Procura-se, então, discutir, numa visão prospectiva, uma nova divisão de funções entre os Poderes Executivo Legislativo, especialmente no que concerne produção normativa, cujo modelo atual, ainda fundado no dogma da reserva de lei, apresenta-se incapaz de responder com grau de agilidade e competência que se exige do Estado atual. Remanesce, obviamente, preocupação com preservação dos valores democráticos com contenção do poder do Executivo, que instruíram formação dos Estados constitucionais, mas monopolização, pelo Legislativo, da produção de normas gerais abstratas não fator imprescindível ao alcance de tais objetivos sequer corresponde ao modelo empiricamente em vigor no Brasil. No outro aspecto, da divisão vertical de funções determinada pelo modelo federativo brasileiro, aborda-se "crise de relacionamento" entre os Entes Federativos, que se nota na dificuldade de adoção de políticas públicas conjuntas, problema que mais se agrava ante justa demanda da sociedade em encontrar, para seus organismos, espaço de participação nessa mesma seara. Deixando parte algumas sugestões de reconfiguração federativa, com inclusão ou exclusão de Entes, presente estudo procura defender adoção de soluções institucionais para a concretização da cooperação entre os Entes e para participação da sociedade na busca do interesse público.

Transparência e democracia: os avanços e limites na área tributária no Brasil no período pós 1995

Este trabalho tem por objetivo a análise do sistema de arrecadação tributária no Brasil do ponto de vista de sua transparência. Este tema é discutido no contexto das reformas do Estado e à luz da problemática democrática. Nessa perspectiva, é analisada a administração tributária quanto ao aspecto da transparência como requisito da democracia, na relação entre fisco (Estado) e contribuinte (cidadãos). Tomam-se como ponto de referência as medidas adotadas a partir de 1995, que tinham por finalidade dotar a administração pública de melhores instrumentos de gestão, visando ao aumento da arrecadação dos tributos, buscando, ao mesmo tempo, colocar à disposição da sociedade melhores formas de acesso ao aparato tributário. O ICMS no estado de São Paulo é utilizado como a referência principal. Justifica-se o estudo pelo fato de que, no processo de redefinição do papel do Estado, a área tributária é uma das menos estudadas sob o aspecto democrático e é, ao mesmo tempo, uma das que mais atingem a sociedade brasileira.

Planejamento governamental : aspectos teoricos e uma analise das experiencias mundial, brasileira e cearense

O planejamento provoca um fascínio e deslumbramento no homem desde os primórdios do seu aparecimento, quando procura antever o futuro, que se lhe apresenta desconhecido e misterioso. Uma das características do ser humano é fazer planos, sendo essa atividade uma atitude inerente ao homem e também às sociedades. A literatura brasileira, disponível sobre o tema, apresenta-se de uma certa forma dicotômica, quase sempre sem uma unidade orgânica, ora produzindo parcos estudos teóricos, ora fornecendo análises de experiências específicas de países, regiões e estados em períodos de tempo determinados. A dissertação de mestrado para a Escola Brasileira de Administração Pública - EBAP Fundaçâo Getúlio Vargas - FGV,Planejamento Governamental. Aspectos teóricos e uma análise das experiências mundial, brasileira e cearence, consolida num só estudo os aspectos teóricos e práticos dentro de um encadeamento lógico,didático com o objetivo de revisitar/esclarecer o tema e servir de mate rial de consulta/referência para cursos de graduação e pós-graduação da disciplina Planejamento Governamental. Para uma melhor compreensão das experiências de planejamento, apresenta inicialmente os aspectos teóricos, conceituando o tema e relacionando suas funções ~ características. O trabalho mostra o inter-relacionamento do, planejamento com o poder e a política, incluindo a discussão do mito da neutralidade e racionalidade, assim como' sua utilização como instrumento nas mãos dos que detêm o poder, Demonstra também o caráter do plnejamento como processo com definições e a descrição de três modelos teóricos - Bromley, Tristão e Hilhorst. Apresenta o dilema liberdade do setor privado versus intervenção governamental, desde as primeiras manifestações de planejamento na Rússia, após a revolução de outubro de 1917 passando pelas experiências da Europa e Estados Unidos da América, até a dos países subdesenvolvidos, cada qual com suas condições históricas e institucionais peculiares. Faz uma análise da experiências mundial e brasileira (dividida em fases: ocasional - até 1930, empírica 1930-1964 e científica 1964-1986), sendo que para esta última adota uma abordagem síntese baseada nos pontos de vista de diversos autores examinados, principalmente Benedicto Silva, Werner Baer, Issac Kerstenetzky, Anniba1 V. Villela, Jorge Vianna Monteiro e Luiz Roberto Aze vedo Cunha. No caso da experiência cearense ( 1963-1986 ), a descrição factual e linear dos planos tem uma seqUência temporal (a exemplo dos planos brasileiros), forma meramente didática escolhi da e visa uma melhor compreensão do assunto. Paralelamente, analisa os planos em seus aspectos econômico, social, político e cultural de forma integrada, numa tentativa de dimensionar a história total do planejamento estadual. O enfoque tradicional de comparação objetivos propostos/objetivos alcançados, muito comum nas análises das experiências de planejamento, é deixado de lado stricto-senso. Em contrapartida, dá ênfase a um aspecto que julga mais relevante: a identificação da evolução dos arranjos organizacionais, visto ser o planejamento algo que neles se traduz e cuja exequibilidade depende, em alto grau, do contexto institucional. Isentando o conceito do planejamento de culpa pelo seu fracasso no atingimento da maioria de seus objetivos, o trabalho aponta uma série de fatores particularmente desfavoráveis que configura uma situação de crise: Objetivos apologéticos e triunfalistas; retórica inócua; uso do planejamento no sentido de fortalecedor e viabilizador dos interesses da classe dominante; exarcebação da técnica e tese da neutralidade do planejamento para efeito de obtenção de poder; manipulação do planejamento como instrumento de mistificação, assim como seu uso como fetiche e servidor de "trampolim" para a política (principalmente no Ceará); a eliminação do caráter federativo da União Republicana, provocando a perda de autonomia dos estados com o sistema tributário, conduzindo a uma centralização das decisões ( e do poder )'; ausência de continuidade nas políticas econômicas de longo prazo tendo como corolário a descontinuidade administrativa e, por último, a própria natureza do planejamento posto em prática no Brasil e no Ceará que, sendo indicativo, não detém o controle de todas as variáveis do processo. O aparecimento de um novo paradigma para o planejamento governamental passaria, necessariamente, pela antítese dos entraves apontados no estudo.

Avaliação de impacto do Programa de Modernização Tributária e da Gestão dos Setores Sociais Básicos (PMAT) na arrecadação de ISSQN e IPTU dos municípios, no período de 1999 a 2011

O objetivo deste trabalho é avaliar o impacto do Programa de Modernização da Administração Tributária e da Gestão dos Setores Sociais Básicos (PMAT), gerido pelo Banco Nacional de Desenvolvimento Econômico e Social (BNDES), na arrecadação tributária dos Municípios, no período de 1999 a 2011. Para tanto, utilizamos um modelo econométrico de dados em painel com estimador de efeitos fixos. As variáveis dependentes são os logs da arrecadação de ISSQN e IPTU, as variáveis explicativas são os desembolsos do BNDES e o PIB municipal desagregado. Realizamos regressões com dummies de tratamento e com o log dos desembolsos. Além realizar regressões com toda a amostra disponível, delimitamos a amostra do grupo de controle em dois subgrupos para tentar eliminar efeitos de tendências entre entidades. A primeira delimitação foi utilizar a amostra que realizou consultas ao banco de fomento e não obteve sucesso. A segunda delimitação foi a de municípios que possuem proximidade geográfica daqueles comtemplados pelo financiamento. Os resultados encontrados demonstram não haver significância estatística entre desembolsos realizados pelo BNDES e a trajetória da arrecadação dos tributos em análise na maior parte dos modelos utilizados. Apenas nas regressões com dados da amostra que realizou consulta ao BNDES, obteve-se significância estatística, ao nível de 5% para o tributo IPTU, no efeito acumulado ao longo do tempo.

Do talão de nota fiscal ao cupom fiscal: a implantação do ECF no estado do Rio Grande do Norte e sua repercussão na arrecadação do ICMS

The present paper has aimed the analysis of a real instrument which offers great impact in the ICMS revenue: The Fiscal Voucher Emitting Equipment (ECF). In this sense, the effects of the commercial automation process in Rio Grande do Norte s ICMS revenue between 2000 and 2006 were investigated. Based on this goal, the methodology adopted was characterized as a study of quantitative, exploratory-qualitative nature, through the collecting of secondary data, provided by the State Taxation Bureau (SET). In the absence of a statistic model in the existing literature about the approached theme, we decided for the elaboration of a suitable model, with tables and graphics. As a way to observe the effects of these programs on the revenue, the comparison between the ECF users and non users, in the same period, has proved to be of great importance. We reached the conclusion that even though the growth rates amongst the activities that use the ECF had ascended in tributary revenue in the related years, from 2004 on, with the introduction of TEF, this participation presented a higher growth, which leads us to suppose that the use of this recent instrument provides a significant impact in the State effective revenue. We stand out that the collected amounts could have been even higher, if the level of adhesion to the instrument had not been so low, mainly amongst the minor entrepreneurs, which may mean a rooted defraudation in the system. In short, through the set of data obtained, it is possible to conclude that the ECF and the recent TEF have significantly influenced the ICMS revenue in the entire State all over the period that was analyzed

Caracterização limnológica e determinação da capacidade suporte do reservatório mendubim, (Rio Grande do Norte) para o cultivo de peixes em tanques-rede

The aims of this study were: i) assessing the trophic state of the Mendubim reservoir (semi-arid, Rio Grande do Norte, Brazil; 05° 38 99,0 S 36°55 98,0 W) based on chlorophyll-a, total phosphorus and nitrogen concentrations and water transparency; ii) relating the patterns of temporal variation of zooplankton and phytoplankton to the trophic state of the reservoir and iii) investigating the carrying capacity of the reservoir for cage fish farming. The samplingwas done monthly from July 2006 to July 2007 in three stations at the reservoir: next to the dam (barrage), in the central region and in the mouth of the main tributary. The abiotic and biotic variables analyzed were: Secchi depth, volatiles and fixed suspended solids, chlorophyll-a, total phosphorus and nitrogen, TN:TP ratio and mesozooplankton and phytoplankton composition and biomass. The results showed that the reservoir can be considered as mesotrophic with mean concentrations of total nitrogen, phosphorus and chlorophyll-a equal to 1711, 1 μg.L-1, 30,8 μg.L-1 and 5,62 μg.L-1 respectively. The Cyanophyceae class was the most representative in terms of density, with the presence of potentially toxic species such as Microcystis aeruginosa, Planktothrix planctonica, Cylindrospermopsis raciborskii, Aphanizomenon sp. ,Aphanocapsa delicatissima and Pseudanabaena acicularis. Among the zooplankton, the genus Notodiaptomus presented the largest biomass values. Overall, our results show that the light limitation should explain the weak relationship between chlorophyll-a and total phosphorus and nitrogen concentrations. We concluded that the water of Mendubim reservoir is suitable for intensive fish cage aquaculture. Based on the carrying capacity calculations for this reservoir, we found that the maximum sustainable yield of tilapias in cages in the reservoir is 126 ton per year assuming a factor of food conversion of 1.5: 1.0 and a phosphorus content in the fish food of 1%

A influência da poluição difusa e do regime hidrológico peculiar do semiárido na qualidade da água de um reservatório tropical

In semiarid region of northeast Brazil, the majority of reservoirs used for public supply has suffered degradation of water quality affected by diffuse pollution from agricultural and livestock areas of the watershed and by hydrologic regime peculiar to the region, characterized by a rainy season with higher volumes stored in reservoirs and a dry season with a reduction in water level due to high evaporation and increase of eutrophication. The Dourado reservoir, located in Currais Novos city, semiarid region of Rio Grande do Norte state, is one example of a water supply reservoir that can have degradation of water quality and impracticability of their use, due to the high external input of nutrients from non-point sources of watershed during the rainy season and increasing of eutrophication due to decrease the stored volume during the dry period. This study aimed to investigate and quantify diffuse pollution and the hydrologic regime of semiarid region in order to establish standards regarding the water quality of Dourado reservoir. The study period was between the months of May 2011 to March 2012. The diffuse pollution was quantified in terms of watershed from the mass balance of phosphorus in the reservoir, as in relation to areas under different types of land use within the riparian zone of the reservoir from the assessment of soil chemical properties and losses of phosphorus in each area. The influence of hydrological regime on water quality of the reservoir was evaluated from the monthly monitoring of the morphometric, meteorological and limnological features throughout the study period. The results showed that the reservoir has received a high load of phosphorus coming from the drainage basin and presents itself as a system able to retain some of that load tributary, giving an upward trend of the eutrophication process. Diffuse pollution by nutrients from areas under different types of land use within the riparian zone of the reservoir was higher in areas under the influence of livestock, being this area considered a potential diffuse source of nutrients to the reservoir. Regarding the water regime during the rainy season the reservoir was characterized by high concentrations of nutrients and small algal biomass, while in the dry season the reduction of volume and increase of the water retention time of the reservoir, contributing to the excessive growth algal biomass, favoring an increase in eutrophication and deterioration of water quality. In synthesis the water quality of Dourado reservoir is directed by diffuse pollution coming from the drainage basin and the hydrological regime of the peculiar semiarid region, where the rainy season is characterized by high input of allochthonous compounds from the tributaries and erosion of the soil in the reservoir riparian zone, and the dry season characterized by reducing the storage volume due to high evaporation, high residence time of water and consequent degradation of water quality due to the increase of eutrophication process

O efeito do regime hidrológico do semiárido na composição de espécies durante dominância de cianobactérias em um reservatório tropical

The potentially toxic cyanobacterial blooms in water bodies are spread across the globe, resulting in the loss of water quality and adverse effects on human health. In arid and semiarid regions, the hydrologic regime characterized by an annual cycle of drought and rain, change the volume and the retention time of the reservoir. Such changes affect the limnological characteristics and causing changes in composition and biomass community of cyanobacteria. The reservoir Cruzeta (Zmax = 8.7 m) is a eutrophic water supply source located in the semiarid tropical (Northeast Brazil). Raised the hypothesis that the hydrological regime of semi-arid tropical is a determining factor in the availability of resources in eutrophic water sources, which influences the composition of dominant species of cyanobacteria. The aim of this study was to analyze the changes in biomass and species composition of cyanobacteria for two annual hydrological cycles and evaluate factors drivers. The study was divided into five distinct periods (dry 2010, rain 2011, dry 2011, rain 2012, dry 2012). The dominant group found in all periods was Cyanobacteria (99% of total biomass), which contributed to the low diversity. The filamentous species Cylindrospermopsis raciborskii was present at both points in almost every study. The colonial species Microcystis panniformis and Sphaerocavum brasiliensis dominated only in periods with lower volumes of water. The diatoms contribute more to the biomass during the period of severe drought. The point near the dam (P1) had phytoplankton biomass larger than the point near the tributary (P2). The dominant species of colonial cyanobacteria lasted until the overflow in P1, and P2 this dominance was until the first rains. The redundancy analysis indicated that physical factors such as light availability and water level were the main factors driving the seasonal succession of phytoplankton. The composition of phytoplankton in spring was alternated by species of filamentous cyanobacteria in conditions of poor stability of the water column, such as Cylindrospermopsis raciborskii, and colonial species under conditions of high stability of the water column, such as Microcystis panniformis and Sphaerocavum brasiliensis. The extremes of torrential rains and severe droughts, governed by the hydrological regime of the semi-arid region led to the availability of resources in the watershed, directing the spatial and temporal dynamics of phytoplankton in the reservoir Cruzeta

Diagnóstico operacional de lagoas de estabilização

This work intends to develop an approach based through scientific criteria in the operational diagnosis of ponds of stabilization, starting from analyses accomplished in loco and in laboratory of 78 systems of sewer treatment through ponds of stabilization in the State of Rio Grande do Norte. The objectives of the research are: to map, to evaluate and to diagnose the operational acting of the ponds of stabilization of the state of Rio Grande do Norte, through visits in loco and analyses laboratory; to build a SIG, through the map rain, locate the points of releases of sewages of the systems of existent ponds in Rio Grande do Norte, as well as operational data and his/her respective efficiency diagnosis in the removal of BOD and Coliforms Termotolerantes; to evaluate, in real scale, three systems of ponds of stabilization of RN in the operational efficiency for the parameters BOD5, COD, pH, Temperature, OD and Coliforms Termotolerantes. Of 78 ETEs of appraised RN just, 9% or 7 had maximum concepts in what concerns the removal of BOD and Coliforms Termotolerantes and 41% or 32, they had the worst concepts in term of operational efficiency. The flowing concentrations ETEs of RN of BOD and Coliforms were of 410mg/L and 2,50x107UFC/100ml, the predominant configuration is of the type F1+M1+M2, the relationship BOD/COD revealed for the sewer tributary characteristic biodegradable high. For the study of case of 3 ETEs, the best operational efficiencies in decreasing order were: Cidade (Municipal district), it Roça (State) and São Miguel (SAAE). The removals of final BOD were 51,6mg/L; 108,27mg/L and 62,6mg/L, tends efficiency of 82%; 74% and 81%. In term of coliforms removal in the final effluentes were 1,90x103UFC/100ml; 1,50x104UFC/100ml and 3,10x104UFC/100ml, tends efficiencies of 99,99%; 99,95% and 99,90%. In what it concerns the practice of agricultural reúso of cultures consumed raw, none of 3 ETEs assisted the parameters of the Resolution CONAMA 357/05, for other reúso practices, all assisted the categories B and C of OMS. For release in body receiving ETE Cidade just, they assist the demands of the resolution of CONAMA 357/05, by study of purification solemnity of the receiving body. The maintenance lack and operation; exclusive operator in ETEs and operation knowledge was the contributory factors for the operational fall in appraised ETEs of RN

Composição ictiofaunística e estratégias reprodutivas de quatro espécies de peixes nativos da Bacia Hidrográfica Piranhas - Assu, Rio Grande do Norte

This study focuses on the fish fauna composition and reproductive strategies of four native fish species in relation to environmental variables of the Piranhas-Assu hydrographic basin of the Caatinga biome, Rio Grande do Norte, Brazil. Fish and environmental data were collected monthly during the period September 2008 to February 2010, in the Marechal Dutra reservoir and River Acauã a tributary of Piranhas- Assu. The fish were measured, weighed and dissected, and the gonads were removed, weighed and examined macroscopically for identification and determination of gonad maturation stages. The results of this work generated seven articles. The first article is about the fish fauna composition of the Piranhas-Assu hydrographic basin, Rio Grande do Norte. The 602 fish samples captured were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families and 22 species, of which 17 are endemic to the Caatinga ecoregion. The order Characiformes was more representative followed by Perciformes, Siluriformes and Synbranchiformes. The second article is about the length-weight relationship and growth of seven native fish species Crenicichla menezesi, Cichlasoma orientale, Triportheus angulatus, Psectrogaster rhomboides, Pimelodella gracilis, Prochilodus brevis and Leporinus piau from a semiarid Brazilian reservoir. The third article is about the reproductive aspects of Crenicichla menezesi. Males were larger, heavier and with a slight predominance as compared to females. Four stages of gonadal development were characterized, being immature, maturing, mature and spent. The females reached sexual maturity earlier than males, with an average fecundity of 398 oocytes per batch. The spawning was partial with a long reproductive period. The fourth article deals with the reproductive strategy of Leporinus piau a neotropical freshwater fish in semi-arid region of Brazil. The population of L. piau (n = 211) showed a slight predominance of males (55%), with larger and heavier females. The males matured earlier than the females. This species presented total spawning, with an average fecundity of 55,000 mature oocytes. Rainfall and concentration of dissolved oxygen acted as influential factors during the spawning season. L. piau shows a seasonal reproductive strategy. The fifth article is related to the morphometric-meristic characteristics and reproductive aspects of freshwater sardine, Triportheus angulatus from River Acauã of the Caatinga biome. There was a predominance of larger females, reaching first maturation before males. There was total spawning during the rainy period of the region. The sixth article reports on the reproductive strategy of Psectrogaster rhomboides. The sex ratio was 1M: 1F, with negative allometric growth. Males reached sexual maturity earlier than females Females and males showed four stages of gonadal development and spawned during the rainy season. The fecundity was low and this species presented total spawning. The seventh article reports on the dynamics of territorial behavior of Crenicichla menezesi. Ten agonistic behaviors displayed by the males were observed: frontal and lateral threat, chasing, circular chasing, perpendicular, lateral and mouth attacks, escape, parallel positioning and stationary. The formation of four social groups was observed among males: without interaction; interaction with submission and escape; with frontal and lateral agonistic interactions. In social interactions between males and females, it was observed that the larger males interacted more among themselves and with the larger females. The large male established its territory and the two small males along with the small female were excluded from the other groups. These studies clarified the fish fauna composition and reproductive strategies of four native species Crenicichla menezesi, Leporinus piau, Triportheus angulatus and Psectrogaster rhomboides of the Piranhas- Assu hydrographic basin of the Caatinga biome, Rio Grande do Norte, Brazil.

Approach combining on-line metal exchange and tangential-flow ultrafiltration for in-situ characterization of metal species in humic hydrocolloids

This paper deals with the development and optimization of an analytical procedure using ultrafiltration and a flow-injection system, and its application in in-situ experiments to characterize the lability and availability of metal species in humic-rich hydrocolloids. The on-line system consists of a tangential flow ultrafiltration device equipped with a 3-kDa filtration membrane. The concentration of free ions in the filtrate was determined by atomic-absorption spectrometry, assuming that metals not complexed by aquatic humic substances (AHS) were separated from the complexed species (M-AHS) retained by the membrane. For optimization, exchange experiments using Cu(II) solutions and AHS solutions doped with the metal ions Ni(II), Mn(II), Fe(III), Cd (II), and Zn(II) were carried out to characterize the stability of the metal-AHS complexes. The new procedure was then applied in-situ at a tributary of the Ribeira do Iguape river (Iguape, São Paulo State, Brazil) and evaluated using the ions Fe(III) and Mn(II), which are considered to be essential constituents of aquatic systems. From the exchange between metal-natural organic matter (M-NOM) and the Cu(II) ions it was concluded that Cu(II) concentrations > 485 mu g L(-1) were necessary to obtain maximum exchange of the complexes Mn-NOM and Fe-NOM, corresponding to 100% Mn and 8% Fe. Moreover, the new analytical procedure is simple and opens up new perspectives for understanding the complexation, transport, stability, and lability of metal species in humic-rich aquatic environments.