Bacterial cellulose/triethanolamine based ion-conducting membranes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sistema com aeração, decantação e filtragem para a melhoria da qualidade de água em irrigação localizada

A qualidade da água é muito importante para irrigação por gotejamento, pois ela escoa por pequenos bocais dos emissores, podendo ocorrer obstrução devido à deposição dos sólidos em suspensão. Portanto, antes da instalação do projeto, devem-se avaliar parâmetros de qualidade da água, para adotar medidas preventivas, evitando o risco de entupimento do sistema. Este trabalho teve como objetivo avaliar um sistema composto por aeradores com aspersores, sobre leito de pedra, para a precipitação dos íons Fe+2e Mn+2 em tanque de decantação, e um conjunto de filtragem composto por três filtros de areia e um de disco, em sistema de irrigação localizada. O trabalho foi realizado na Fazenda Alvorada, no município de Nova Granada - SP, no período de março a outubro de 2008. Foram realizadas determinações de variáveis físicas e químicas da água, ao longo do sistema de aeração, decantação e filtragem, o qual foi eficiente para a melhoria da qualidade de água, reduzindo os níveis de risco de entupimento de severo para médio e de médio para baixo. Oxigênio dissolvido, condutividade elétrica, pH, Fe+2e Fe+3 não diferenciaram a qualidade de água entre os pontos do sistema de tratamento, porém a turbidez, sólidos dissolvidos, sólidos em suspensão, ferro total e manganês total reduziram-se significativamente pelo uso do sistema proposto, melhorando a qualidade da água.

Variação sazonal da abundância de Ecballocystis pulvinata Bohlin em um riacho da região centro-sul do estado do Paraná

Seasonal variation of abundance of Ecballocystis pulvinata Bohlin in a stream of central-southern region of Parana State. The temporal dynamics of E. pulvinata and its relation to abiotic variables were evaluated monthly during January to December 2007 in a stream located in the central-southern part of Parana State (25 degrees 11'16 '' S - 51 degrees 021'25 '' W). The abundance of the population in terms of percentage cover was obtained by means of the quadrat technique and the following stream water variables were measured: current velocity, irradiance, depth, substrate type, temperature, oxygen saturation, conductivity, pH and turbidity. The abundance of E. pulvinata was considered high (X = 26.7%), with more development (22-46%) during autumn/winter. The low values (0-0.08) of niche width and the few associations with environmental variables shows that the population evaluated is a generalist with regards to the environment in which it occurs. Factors most strictly related were the water flow and the particle size of the substrate, which positively correlated to the seasonal pattern of the population investigated.

Impacto da manutenção de reprodutores de macrobrachium rosenbergii na qualidade da água

Our objective was to evaluate the impacts caused on pond water quality by maintenance of Macrobrachium rosenbergii broodstock. During eight weeks we determined pH, dissolved oxygen (DO), conductivity, turbidity, particulate suspended material (PSM), nitrogen (N) and phosphorus (P), all in inlet and effluent water. All variables presented higher values in the effluent, except OD. N-ammoniacal concentration (0.013 mg L(-1)) was 2.7 times higher in the effluent pond; NO(2)-N (0.019 mg L(-1)), 2.3; NO(3)-N (0.139 mu g L(-1)), 1.8; PO(4)-P (0.065 mg L(-1)), 7.2; and DP (0,104 mg L(-1)), 4.9 times higher. For TKN (0.67 mg L(-1)) and TP (0.235 mg L(-1)) the values in the pond effluent represent an increase of 0.27 mg L(-1) and 0.175 mg L(-1), respectively. The maintenance of M. rosenbergii broodstock increase the nutrient concentrations, mainly TP, prevent effluent pond released into receiving water bodies on 1, 2 and 3 classes of the CONAMA N degrees 357 Resolution.

Diet and capture of Hypostomus strigaticeps (Siluriformes, Loricariidae) in a small brazilian stream: relationship with limnological aspects

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of daily changes in environmental factors on the abundance and richness of Odonata

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anthropogenic influences on annual flux of cations and anions at meio stream basin, São Paulo State, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Abundance of zooplankton from different zones (pelagic and littoral) and time periods (morning and night) in two Amazonian meandering lakes

The abundance of zooplankton in two lakes of Southwest Amazonia was studied for 10 months in different regions and at different periods of the day. The lakes were Lago Amapá, located at 10°02′36″S, 67°50′24″W, and Lago Pirapora, at 9°27′21″S, 67°31′39″. Both lakes are characterized as oxbow lakes. The aim of this study was to compare the pelagic and littoral regions, as well as to determine differences in the distribution of zooplankton in the water column in the morning and at night. Collections were made by filtering water through a 55μm zooplankton net into a 5L Van Dorn bottle, collecting 4L from the top and 5L from the middle and bottom layers, totaling 14L of water for each sampling location. In addition, physical and chemical parameters were measured, including transparency, temperature, pH, dissolved oxygen, electrical conductivity and turbidity. Anova (analysis of variance) and Tukey's test were used. There was no statistically significant difference between the regions studied, nor between the two time periods examined. The results of the Pearson correlation (p<0.05) demonstrated that the physical and chemical characteristics of the water correlated with the cladocerans Moina spp. (represented by M. minuta and M. reticulata) and Ceriodaphnia cornuta, and that Daphnia gessneri was associated with Chaoboridae.

Condições hidrológicas de uma bacia hidrográfica com diferentes usos do solo na região de taquaritinga, SP

In areas where human activities, as agriculture, are developed land use contributes to physical, chemical and biological characteristics of water. This study aimed to identify physical and chemical variations of the water monitoring network in 4 first magnitude watersheds with different land use/occupation in the hydrographic basin of the Glori Farm Creek in the city of Taquaritinga, State of Sao Paulo, from February to July, 2005. The methodology consisted of weekly sample water collections to naalyze turbidity, temperature, dissolved oxygen, pH and electric conductivity. The characterization of the hydrological conditions of the watersheds showed that agricultural activities, including the productive system of the sugarcane cultivation, have affected the quality of water resources.

Microscopic and dielectric analyses of vanadium and tungsten modified barium zirconium titanate ceramics

Dielectric spectroscopy was used in this study to examine polycrystalline vanadium and tungstendoped BaZr 0.1Ti 0.90O 3 (BZT10:2V and BZT10:2W) ceramics obtained by the mixed oxide method. According to X-ray diffraction analyses, addition of vanadium and tungsten lead to ceramics free of secondary phases. SEM analyses reveal that both dopants result in slower oxygen ion motion and consequently lower grain growth rate. Temperature dependence dielectric study showed normal ferroelectric to paraelectric transition well above the room temperature for the BZT10 and BZT10:2V ceramics. However, BZT10:2W ceramic showed a relaxor-like behavior near phase transition characterized by the empirical parameter γ. Piezoelectric force microscopy images reveals that the piezoelectric coefficient is strongly influenced by type of donor dopant suggesting promising applications for dynamic random access memories and data-storage media. Copyright © 2010 American Scientific Publishers All rights reserved.

Reproduction, food dynamics and exploitation level of Oreochromis niloticus (Perciformes: Cichlidae) from artisanal fisheries in Barra Bonita Reservoir, Brazil

Nile tilapia (Oreochromis niloticus), which is exotic to South America, is the most common species caught in artisanal fisheries at the Barra Bonita Reservoir, Southeastern Brazil. This species is of great socioeconomic importance for the region and keeps active a population of about 500 fishers. In the present study we assess reproduction, food dynamics and level of exploitation of O. niloticus, caught by artisanal fisheries in the Barra Bonita Reservoir. Specimens were collected monthly, from July 2004-June 2005, and a total of 1 715 specimens were analyzed. Each specimen was examined to obtain biological and biometric data: standard length (cm), total weight (g), reproductive data (sex and stage of maturation), and stomach contents (empty, partly full, and full). We also estimated the sex ratio (by macroscopic observation of gonads), reproductive period (by ovarian development and seasonal average of gonadosomatic index in females), and feeding habits (by stomach contents). The possible relationship between abiotic factors and the reproductive period was statistically verified using Spearman's Rank Correlation. The FiSAT (ELEFAN I) package was used to assess growth parameters, mortality rates and to infer exploitation rate from standard length frequencies. The O. niloticus population had a sex ratio of 1.3:1 (M:F). Results indicated that ripe females were captured throughout the year, with a higher frequency during the winter-2004 (with a frequency of 59%, at a mean temperature of 20.5°C), and in spring-2004 (with a frequency of 60.5% at a mean temperature of 21.18°C). The GSI mean values obtained by season were: winter-2004: 1.71; spring-2004: 1.72; summer-2005: 0.80, and autumn-2005: 1.19. The Spearman correlation indicated positive values with respect to pH, dissolved oxygen, electric conductivity, transparency and chlorophyll a, and negative values with respect to temperature, accumulated rainfall and altimetric benchmark. The main food items were phytoplankton and periphytic algae, observed in 99.6% of the analyzed stomachs. The estimated growth and mortality parameters were: L∞=33.60cm, k=0.63/year, longevity= 4.76years, Z=2.81/ year, M=1.20/year and F=1.61/year. The weight-length relationship was Ln Wt=-2.8532+2.8835 Ln Lp. The estimated yield per recruit values were as follows: E=0.570, Emax=0.776, E0.1=0.604 and E0.5=0.349. These results indicate that a well established population of O. niloticus is present at Barra Bonita Reservoir; with an active reproduction throughout the year, more intense during winter and spring, and that O. niloticus is a phytoplanktophagus species. There were no indications that this species is being overfished, we therefore recommend that, due to its exotic condition, no restrictions need to be taken on its fishing activities.

Caracterização de efluentes de viveiros de engorda de rã-touro (lithobates catesbeianus, Shaw, 1802)

Aim: Current analysis characterizes the effluent from bullfrog-rearing ponds during the grow-out phase; Methods: Temperature, pH, dissolved oxygen, electric conductivity, turbidity, total phosphorus, N-NH3, N-NO3, BOD5 and COD and the number of thermotolerant coliforms (Escherichia coli) of the inlet and outlet water of the ponds were analyzed twice a week. Assay consisted of a completely randomized experimental design with two treatments (inlet and outlet water) and six repetitions in a split-plot, coupled to collection over time as subplot; Results: All variables were significantly different (p < 0.05) between treatments and over time (p < 0.05). Average rates of temperature, pH and dissolved oxygen levels of the supply water were higher when compared to those of the effluent. The other variables such as conductivity, turbidity, total phosphorus, ammonia, nitrate, biological oxygen demand, chemical oxygen demand and E. coli were higher in the effluent when compared to rates in the supply water; Conclusions: The management during grow-out phase caused the deterioration of the water quality, with increasing levels of dissolved nutrients and the number of thermotolerant coliform. Ammonia and phosphorus levels in the effluent, caused by waste food, skin and feces, accelerate the eutrophication process of the receiving water body. Further studies on effluent treatment are required.

Avaliação da qualidade de efluentes na criação de rã-touro (Lithobates catesbeianus)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de macrófitas aquáticas flutuantes no tratamento de efluentes de carcinicultura

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise do potencial de impacto no meio ambiente como ferramenta para educação e proteção ambiental em pesqueiros

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)