959 resultados para Madeira River basin


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Fluvial morphometry is method of great value regarding neotectonic analysis of extensive areas because streams, besides representing one of the main agents in the relief modeling, quickly adjust their thalwegs to even the most gentle crustal deformations. The purpose of this paper is to present the application of some morphometric techniques in the Santo Anastácio River hydrographic basin in order to identify recent tectonic deformations. Additionally, we show liquefaction structures identified in the basin and interpreted here as seismites linked to ancient earthquakes (magnitudes greater than 5). The morphometric survey includes longitudinal stream profile analysis, RDE (declivity versus stream length) index application, and the sinuosity study of the Santo Anastácio River channel. Geologic substrate comprises Cretaceous siliciclastic rocks of the Caiuá and Bauru groups, locally covered by Cenozoic sediments (alluvial plains, terrace deposits, colluvial aprons, as well as in situ regoliths). Considering that liquefaction structures affect dark clay layers of 32.340±320 year BP age (14C dating), a lower age limit for the ancient earthquake is triggered in that region. The authors believe that neotectonic understanding of the Western São Paulo State Plateau is important to the geologic and geomorphologic evolution of that landscape and to the consequent territorial planning and occupation.

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The Permian-Carboniferous Itararé Group is one complexe lithostratigraphic unit of the Paraná Basin, southeastern Brazil, typically marked by discontinuity of its lithofacies. Under the exploratory point of view, the unit represents one of the most significant intervals of the basin, since several occurrences of mineral and energetic resources are associated to it, as groundwater, petroleum and coal. The prospection and exploitation of these resources depend on a good understanding of the stratigraphic architecture and the paleogeography. There are many contributions on the specialized literature which deal with this subject, although the regions of Limeira and Piracicaba (superior portion of the unit) still lack new investigations, which may contribute to the understanding of its lithofacies and related sedimentary processes. It was analyzed the sedimentary sets pilling up, followed by stratigraphic correlations between the two regions. Moreover, from sedimentary structures, it was made paleocurrent measurement with the purpose of obtaining indicative patterns of the sedimentary polarity, contributing for the comprehension of the paleogeography. Recent studies in the Domo de Pitanga region (between Rio Claro and Piracicaba cities) and in the Corumbataí river drainage basin, were taken also as basis for possible correlations. It was obtained a frame of the lithofacies arrangement, their vertical and lateral relations, as well as their depositional polarities.

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This paper presents the results of the longitudinal profile analysis and the application of gradient index (RDE) in the Patos River, a tributary of the Ivaí River basin, PR. The goal is identify and quantify the anomalous zones along river course concerning their genesis - activity neotectonic or/and lithological imposition. The Patos River has a length of 127 km and a relief amplitude of 660 m, The occurrence of an important knickpoint in the middle course the Patos River can be divided into two stretches. Of the 22 sections measured, 10 were considered anomalous, distributed in both upper and lower course. In the upper course, over a basaltic bedrock of the Serra Geral Formation the RDE values are lower than those in the lower course, where river flows over sedimentary rocks of the Terezina Formation. The 2 nd order anomalies are related to lithological changes, relief alignments and channel confluences - as in the case of São João River. The 1st order anomalies are linked to differences in rock resistance associated with structural control, which provides the formation of waterfalls.

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As imagens aerofotogramétricas de uma região registram os vários aspectos da paisagem, destacando a cobertura vegetal, a rede de drenagem e principalmente o relevo do terreno conjunto que caracterizam unidades morfométricas denominadas bacias hidrográficas. Neste trabalho aplicaram-se técnicas fotointerpretativas e estatística multivariada a variáveis do relevo, medidas em bacias hidrográficas de terceira ordem de ramificação pertencentes à bacia do rio Tiête no município de Botucatu-SP, com o objetivo de agrupar bacias segundo graus de similaridade, bem como inferir sobre a representatividade da distribuição espacial dos agrupamentos em relação ao Mapa Pedológico do Estado de São Paulo, da Embrapa de 1999. Foram utilizadas fotografias aéreas verticais, escala nominal aproximada 1:30000, (2005), cartas planialtimétricas escala 1:50000 e Mapa Pedológico do Estado de São Paulo. Foram estudadas 06 bacias hidrográficas de 3aordem de ramificação, situada na região fisiográfica denominada frente da cuesta abrangendo as unidades de solo Neossolos Litólicos (RL) e Latossolos Vermelhos distrófico (LVdf), sendo esta última predominante na área de estudo. O conjunto de variáveis de relevo mostrou-se eficiente no agrupamento das bacias conforme as unidades de solos ocorrentes, concordando com as unidades identificadas no Mapa Pedológico.

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Cytogenetic analyses were performed in four species of the Hypostominae subfamily, three from Hypostomus (Hypostomini) genus and Rhinelepis aspera (Rhinelepini). Three populations of Hypostomus ancistroides were analyzed, which had 2n=68 chromosomes, but presented different karyotype formulas. Hypostomus regani and H. strigaticeps, both from Ivaí river, showed 2n=72 chromosomes with two distinct cytotypes. In turn, R. aspera of the upper Paraná river basin presented 2n=54 chromosome. Multiple Nucleolar Organizer Regions (NORs) have been evidenced by silver nitrate staining in species of Hypostomus and single NOR in R. aspera. The observed variation in the chromosome number and the marked variability in karyotype formulas and NORs reveal a certain amount of karyotype variation in the genus Hypostomus suggesting the probable existence of cryptic species with independent chromosome traits. Therefore, our data can be of great value in discriminating species and understanding their chromosomal evolution.

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Distribution patterns of most of the 20 Neotropical freshwater turtles belonging to the family Chelidae are usually based on few locality records. We here report on vouchered records of three species of the chelid genus Mesoclemmys in the Brazilian state of Mato Grosso. Presence of M. vanderhaegei is confirmed for the Amazon River Basin, and M. gibba and M. raniceps are recorded in Mato Grosso for the first time. © 2012 Check List and Authors.

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The Nile Tilapia, Oreochromis niloticus, and the Congo Tilapia, Tilapia rendalli, are important members of the African cichlids, and have been introduced to many Brazilian lakes and reservoirs. These species exhibit a large feeding flexibility and may modify their habits during their growth. In the Barra Bonita reservoir, these species are well adapted, representing more than 80% of fish. This study aimed to analyze ontogenetic variation with regard to the diet of these species in this important reservoir. Samples were taken monthly, from March 2007 to February 2008, in Anhembi, São Paulo State. Both species were analyzed by grouping individuals according to size classes. The coexistence of these species was observed in this environment, to which fish were introduced, as well as discreet differences in diet, being that Oreochromis niloticus was considered as an detritivorous, since the detritus was constant in the diet of almost all size classes, and presents some changes in its diet according to the different size classes. While T. rendalli may was defined as herbivorous, and the contribution of food resources to the diet of T. rendalli seems to be different from that of O. niloticus along the size classes.

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The fishes of the present study were collected in the headwater streams of the Sorocaba, Paranapanema and Ribeira de Iguape river basins during the dry period in 2010. A total of 2892 fishes, grouped in 53 species, were captured. The composition of the ichthyofauna captured in the streams of Sorocaba and Paranapanema river basin was greatly similar. On the other hand, the fish fauna of the streams of Ribeira de Iguape river basin were quite different from the ones captured in the others basins, with the occurrence of endangered species (Isbrueckerichthys epakmos and I. duseni) and exotic species (Misgurnus anguillicaudatus). The previous list of fish for the Sorocaba river basin increased with the addition of seven species of Characiformes, one Gymnotiformes and four Siluriformes. © 2012 Check List and Authors.

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The sediment production in river basins is an important aspect for planning the land use. Mathematical models are useful tools for analyzing the problem by providing speed, convenience and flexibility to the simulations of current conditions and future. In this article we evaluate a methodology to simulate the sediment production combining the MUSLE, a hydrologic model (ABC) and a GIS in different scenarios of land use. The models used showed good performance for purposes of planning land use, as well as for agricultural and environmental planning.

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The Ribeira de Iguape River basin received intense mining activities for lead exploiting and, as a result, the river received the discharges of estimated amounts of 5.5 tons/month of material rich in As, Ba, Cd, Pb, Cu, Cr and Zn. In this article, the toxicity of waters and sediments collected in Ribeira de Iguape River was assessed aiming to estimate environmental quality. Three sampling campaigns were conducted, from 2009 to 2010. Toxicity tests with the cladoceran Daphnia similis were done for water samples and for sediments, in this case using sediment-water interface exposure. Results showed in general absence of toxicity for sediments and waters, and only eventually were acute effects registered (marginal toxicity). Results are consistent with the conditions indicated by the literature, of low concentrations of metals in waters and sediments; however they differ from the monitoring made by the state environmental agency, which registered chronic toxicity. The occurrence of eventual acute toxicity indicates that although Ribeira de Iguape River quality is being restored, conditions still are not totally under control.

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A dynamic systems water resources simulation model was developed as a tool to help to analyze water resources management alternatives for the Piracicaba, Capivari and Jundiaí River Water Basins (BH-PCJ). Different politics policy were simulated for 40-year. The model estimates water supply and demand, as well as contamination load from several consumers. Six runs were performed using average precipitation value, changing water supply and demand, and different volumes diverted from BH-PCJ to BH-Alto Tietê For the Business as Usual, the Sustainability Index went from 0.41 in 2010 to 0.22 by 2050; the Water Use Index changed from 80.7% in 2010, to 125.5% by 2050; and the Falkenmark Index changed from 1,302 m 3 person -1 year -1 in 2010 to 774 m 3 P -1 year -1 by 2050. It was noticed that sanitation is one of the biggest concerns in the near future at PCJ River Basin.

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Environmental factors are important in agriculture and need to be considered for getting good degree of development and reasonable efficiency, by reducing their operating costs. To this end, land use shall be appropriated to the conditions offered by the physical elements of the landscape. By facing such questions, this paper aims is to present of mapping the ability of land use of the hydrographic basins Cavalheiro Stream basin (in the city of Analândia - São Paulo State - Brazil) which presents serious erosion problems. Besides it aims to assess if the current land use in this area is consistent with the identified land use ability. For this we have made a cartographic document that spatializes the various classes of usability and its main restrictions. The correlative analysis between that document and land use data showed that Cavalheiro Stream's current use is predominantly inappropriate with the usability of land, which was identified from the physical attributes of the studied area, except for a few sites that are used for forestry and pasture placed in Western, Eastern and Central-South.

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The occurence of carbonatic rocks defines a typical type of relief, called karst, that, by its geomorphology and hydrology, usually differs from the surrounding landscape. In the upper São Francisco river basin, some striking remnants of vegetation associated to karst can be found, which are locally knwon as Mata de Pains. In this region, a mosaic of different physiognomies, including forests and open areas, which present noteworthy plant diversity, composes the vegetation. The aim of this study is to provide an inventory of angiosperm species in areas of carbonatic rocks outcrops in the upper São Francisco river basin karst region, as well as analyze the floristic relationship of the study area with different Brazilian phytogeographic domains. Fieldwork was performed during the period of 2002 a 2006, when collections of fertile speciemns were done in areas associated to carbonatic rock outcrops. During the study, 1512 exsicates were incorporated to BHCB herbarium collection. A total of 456 angiosperm species were inventoried, distributed in 299 genera and 77 families. Herbaceous habit was better represented, with 161 species, followed by shrubs and trees (111 species each) and lianas (73 species). The flora of the study area presents more influence of the Mata Atlântica domain (Atlantic Rain Forest), followed by, in order of importance, Cerrado, Amazonia, Caatinga, Pantanal and Pampa. Floristic surveys in different karst regions inserted in different phytogeographic domains may, together, provide useful information in understanding the phytogeografic history of Neotropical vegetation.

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Fish belonging to the genus Hypostomus are known for exhibiting a striking diversity in its karyotype structure, however the knowledge concerning the distribution patterns of heterochromatin and location of repetitive DNA sequences in the karyotypes is still limited. Aiming a better understanding of the chromosomal organization in this group, we analyzed three sympatric species of Hypostomus collected in the Hortelã stream, a component of the Paranapanema River basin, Botucatu/SP/Brazil. The analyses involved the cytogenetic characterization and chromosomal mapping of repetitive sequences and intra/interspecific comparisons using sequences of the cytochrome C oxidase subunit I. The results revealed that H. ancistroides presents a karyotype with 2n = 68 chromosomes, H. strigaticeps 2n = 72 chromosomes, and H. nigromaculatus 2n = 76 chromosomes. In addition to differences found in the diploid number, it was also observed variations in karyotypic formulae, amount of constitutive heterochromatin, and location of nucleolus organizer regions. The cytogenetic mapping of 5S and 18S rDNA, as well as of the H3 histone gene, disclosed a differential dispersion process among the three species. In some cases the Rex1 transposable element showed to be co-located with 5S rDNA sites. The molecular analyses support the cytogenetic data and represent an additional tool for the characterization of the analyzed species. The results evidenced that chromosomal variations are not restricted to differences in diploid number or karyotypic macrostructure in the genus Hypostomus, indicating that events such as transposition of heterochromatin and rDNA segments may participate in the differentiation process occurred in these species. © 2013 Springer Science+Business Media Dordrecht.