Distribuição e abundância de larvas de Simulium spp.em córregos do estado de São Paulo nos diferentes níveis de qualidade da água

The aim of this work was to determine the distribution and abundance the species of Simulium: in 5 streams of the north coastal region of the state of São Paulo. Simulium larval and water samples were collected every 2 weeks in summer and winter, 2001. The larval were collected on artificial substrates (triplicate) preserved in alcohol (70%) and after analyzed quantitative and qualitative. From the streams the values of temperature, dissolved oxygen, conductivity, pH and stream discharge were measured. The contents of total nitrogen and dissolved nitrogen, ammoniacal nitrogen, nitrate, nitrite, orthophosphate, dissolved phosphorus and total phosphorus were determined in the laboratory. Water quality has great influence in the distribution and abundance of the species. S. pertinax was more abundant in streams without or with low levels of pollution, S. inaequale in streams more polluted and S. incrustatum in intermediary levels of pollution. S. pertinax was the species more abundant with 57.5% of presence in the samples, the second more abundant was S. inaequale with 42.1% of presence and S. incrustatum was rare with 0.4% of presence. The larval abundance was lower in the polluted environment. © 2012 by Unisinos.

A study of the precursors and photoactivity of nanostructures of Ti oxides synthesized by the alkaline hydrothermal method

The present study describes the synthesis, characterization and photocatalytic potential of Ti oxide nanostructures of various morphologies and crystalline phases that were synthesized from 4 different precursors by the alkaline hydrothermal method. The materials were characterized by mainly X-ray diffraction (XRD), Raman spectroscopy, scanning and transmission electron microscopy (SEM and TEM), thermogravimetric analysis (TGA) and X-ray absorption spectroscopy (XAS). Also, photocatalytic potential was assessed by rhodamine B photodegradation. The materials obtained from peroxytitanium complexes (PTCs) exhibited a strong dependence on the concentration of KOH ([KOH]) used for synthesis. The pre-formed sheets of the PTCs were critical to the formation of nanostructures such as nanoribbons, and they were also compatible with the rolling up process, which can be utilized to form structures such as nanorods, nanowires or nanotubes. In the rhodamine photodegradation tests, TiO2 anatase nanostructures with six-coor inated Ti were more effective than the titanate ones (five-coordinated), despite having a smaller surface area and fewer OH groups. The lower photoactivity of the titanates was attributed to the presence of five-coordinated titanium species (TiO5), which may act as electron-hole recombination centers. Furthermore, the material with a mixture of TiO2/titanate was shown to be promising for photocatalytic applications. © 2013 by American Scientific Publishers.

The role of Bi2O3 on the thermal, structural, and optical properties of tungsten-phosphate glasses

Glasses in the ternary system (70 - x)NaPO3-30WO 3-xBi2O3, with x = 0-30 mol %, were prepared by the conventional melt-quenching technique. X-ray diffraction (XRD) measurements were performed to confirm the noncrystalline nature of the samples. The influence of the Bi2O3 on the thermal, structural, and optical properties was investigated. Differential scanning calorimetry analysis showed that the glass transition temperature, Tg, increases from 405 to 440 C for 0 ≤ x ≤ 15 mol % and decreases to 417 C for x = 30 mol %. The thermal stability against devitrification decreases from 156 to 67 C with the increase of the Bi2O3 content. The structural modifications were studied by Raman scattering, showing a bismuth insertion into the phosphate chains by Bi-O-P linkage. Furthermore, up to 15 mol % of Bi 2O3 formation of BiO6 clusters is observed, associated with Bi-O-Bi linkage, resulting in a progressive break of the linear phosphate chains that leads to orthophosphate Q0 units. The linear refractive index, n0, was measured using the prism-coupler technique at 532, 633, and 1550 nm, whereas the nonlinear (NL) refractive index, n 2 was measured at 1064 nm using the Z-scan technique. Values of 1.58 ≤ n0 ≤ 1.88, n2 ≥ 10-15 cm 2/W and NL absorption coefficient, α2 ≤ 0.01 cm/GW, were determined. The linear and NL refractive indices increase with the increase of the Bi2O3 concentration. The large values of n0 and n2, as well as the very small α2, indicate that these materials have large potential for all-optical switching applications in the near-infrared. © 2012 American Chemical Society.

Effects of intensification of the amazon river prawn, macrobrachium amazonicum, grow-out on effluent quality

Studies to determine suitable levels of intensification are essential for developing sustainable aquaculture. The objective of this study was to evaluate the quality of effluents discharged from ponds stocked with 10 (D10), 20 (D20), 40 (D40), and 80 (D80) postlarvae of Macrobrachium amazonicum/m2. Intake and effluent water samples were taken throughout a 5.5-mo grow-out cycle. In that study, twelve 0.01-ha earthen ponds were stocked postlarvae with 0.01g. Average water exchange rate was 15%/d; water was discharged from the bottom of the ponds. Prawns were fed a commercial feed with 38% crude protein according to their biomass (3-10%) and the concentration of dissolved oxygen (DO). In our research, temperature, turbidity, total suspended solids, conductivity, DO, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), N-ammonia, N-nitrite, N-nitrate, N-Kjeldahl nitrogen, total phosphorus, and soluble orthophosphate were measured every 15d throughout the experiment in the early morning (0630 to 0730h). Turbidity was lower in D10 than in D20 and D40 and total phosphorus was higher in D80 than in D10 and D20. An analysis of principal components comparing treatments and intake water showed three groups: intake, D10 and a cluster of D20, D40, and D80. On the basis of the water characteristics found in our study it appears that the farming of M. amazonicum is likely to have a low environmental impact, at least up to a stocking density of 80prawns/m2. © by the World Aquaculture Society 2013.

Comparison of the nanoparticles performance in the photocatalytic degradation of a styrene-butadiene rubber nanocomposite

Much has been talking about the advantages of polymeric nanocomposites, but little is known about the influence of nanoparticles on the stability of these materials. In this sense, we studied the influence of both oxides of zirconium and titanium, known to have photocatalytic properties, as well as the influence of synthetic clay Laponite on the photodegradation of styrene-butadiene rubber (SBR). SBR nanocomposites were prepared by the colloidal route by mixing commercial polymer lattices and nanometric anatase TiO2, monoclinic ZrO2 or exfoliated Laponite clays colloidal suspensions. To better understand the degradation mechanisms that occur in these nanocomposites, the efficiency of different photocatalysts under ultraviolet radiation was monitored by FT-IR and UV-vis spectroscopies and by differential scanning calorimetric. It was observed that TiO2 and ZrO2 nanoparticles undoubtedly acted as catalysts during the photodegradation process with different efficiencies and rates. However, when compared to pure SBR samples, the polymer degradation mechanism was unaffected. Unlike studies with nanocomposites montmorillonite, exfoliated laponite clay effectively acts as a photostabilizer of polymer UV photodegradation. Copyright © 2012 Wiley Periodicals, Inc.

Effects of artificial substrate and night-time aeration on the water quality in Macrobrachium amazonicum (Heller 1862) pond culture

The effects of artificial substrate and night-time aeration on the culture of Macrobrachium amazonicum were evaluated in 12 ponds stocked with 45 prawns m-2. A completely randomized design in 2 × 2 factorial scheme with three replicates was used. The combination of factors resulted in four treatments: with substrate and aeration (SA), with substrate and without aeration (SWA), without substrate and with aeration (WSA) and without substrate and aeration (WSWA). The presence of substrate in SA and SWA treatments reduced suspended particles (seston) by ~17.3% and P-orthophosphate by ~50%. The use of aerator (WSA and SA treatments) significantly (P < 0.05) increased the concentration of dissolved oxygen, suspended particles and nutrients in the pond water. These results indicate that the effect of substrate on turbidity and total suspended solids (TSS) values is opposite to the effect of the aerator. The aerators in semi-intensive grow-out M. amazonicum farming lower water quality because they increased the amount of detritus and nutrients in the pond water. On the other hand, the use of artificial substrate reduces turbidity values, chlorophyll a, TSS and P-orthophosphate concentrations. Therefore, the combination of substrate addition and night-time aeration is not interesting because they have opposite effects. © 2013 John Wiley & Sons Ltd.

Characterization of natural rubber/gold nanoparticles SERS-active substrate

Natural rubber/gold nanoparticles membranes (NR/Au) were studied by ultrasensitive detection and chemical analysis through surface-enhanced Raman scattering and surface-enhanced resonance Raman scattering in our previous work (Cabrera et al., J. Raman Spectrosc. 2012, 43, 474). This article describes the studies of thermal stability and mechanical properties of SERS-active substrate sensors. The composites were prepared using NR membranes obtained by casting the latex solution as an active support (reducing/establishing agents) for the incorporation of colloidal gold nanoparticles (AuNPs). The nanoparticles were synthesized by in situ reduction at different times. The characterization of these sensors was carried out by thermogravimetry, differential scanning calorimetry, scanning electron microscopy (SEM) microscopy, and tensile tests. It is suggested an influence of nanoparticles reduction time on the thermal degradation of NR. There is an increase in thermal stability without changing the chemical properties of the polymer. For the mechanical properties, the tensile rupture was enhanced with the increase in the amount of nanoparticles incorporated in the material. © 2013 Wiley Periodicals, Inc.

Utilização de macrófitas aquáticas flutuantes no tratamento de efluentes de carcinicultura

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Intensificação do cultivo de Macrobrachium amazonicum: efeito das estratégias de estocagem e despesca na água dos viveiros, efluentes e sedimentação em viveiros de crescimento final

Pós-graduação em Aquicultura - FCAV

Tratamento de efluentes de piscicultura utilizando sistema tipo wetland povoado com espécies de macrófitas aquáticas de três tipos ecológicos diferentes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uso de meio a base de esterco suíno no cultivo de Ankistrodesmus gracilis (Chlorophyta) em laboratório

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Qualidade da água e identificação da comunidade fitoplanctônica de um viveiro de piscicultura utilizado para irrigação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização da biointerface nanofios/enzimas para o desenvolvimento de biossensores nanoestruturados

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

Determinação do grau de trofia no Baixo São José dos Dourados por meio da comparação entre dois diferentes índices de estado trófico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Crescimento das macrófitas aquáticas flutuantes Eichhornia crassipes (Mart.) Solms, Pistia stratiotes L. e Salvinia molesta (Mitchell) em diferentes concentrações de nutrientes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)