Sorption aspects for unconsolidated materials of the Sao Carlos region (SP), Brazil

The transport of liquid and gaseous pollutants through porous geological media depends on the physical and chemical characteristics of the unconsolidated material, rocks and water associated with the characteristics of the pollutants. Of these characteristics, the sorption aspect is of fundamental importance and is a function of the mineral proportions, pH, Eh and void aspects encountered in the porous media. In the Sao Carlos region, located in the eastern-central part of the 9 ate of Sao Paulo, Brazil, there are basically two types of unconsolidated materials: the first is a residual from sandstones cemented with fines and the secondarily composed of claystones, siltstones and conglomerates from the Cretaceous Period that constitute the Itaqueri Formation; the second is a sandy sediment of the Tertiary Period. These geological conditions are found in areas where chemical products are disposed of characterized as either diffuse or point pollutions sources. Because of this situation, a study was developed to evaluate the sorption aspects of some inorganic cations that are frequently found in these sources, in varied concentrations. Taken into consideration were their physical/chemical properties, such as: specific weight, grain size, mineralogy, cationic exchange capacity, pH, hydraulic conductivity. Batch tests were run using solutions of KCl, ZnCl(2) and CuCl center dot H(2)O at three different pH values, and then with a combined solution (KCl + ZnCl(2) + CuCl center dot H(2)O), also at three different pH values.

Morphological and molecular characterization of cyanobacteria from a Brazilian facultative wastewater stabilization pond and evaluation of microcystin production

The cyanobacterial population in the Cajati waste stabilization pond system (WSP) from Sao Paulo State, Brazil was assessed by cell isolation and direct microscope counting techniques. Ten strains, belonging to five genera (Synechococcus, Merismopedia, Leptolyngbya, Limnothrix, and Nostoc), were isolated and identified by morphological and molecular analyses. Morphological identification of the isolated strains was congruent with their phylogenetic analyses based on 16S rDNA gene sequences. Six cyanobacterial genera (Synechocystis, Aphanocapsa, Merismopedia, Lyngbya, Phormidium, and Pseudanabaena) were identified by direct microscope inspection. Both techniques were complementary, since, of the six genera identified by direct microscopic inspection, only Merismopedia was isolated, and the four other isolated genera were not detected by direct inspection. Direct microscope counting of preserved cells showed that cyanobacteria were the dominant members (> 90%) of the phytoplankton community during both periods evaluated (summer and autumn). ELISA tests specific for hepatotoxicmicrocystins gave positive results for six strains (Synechococcus CENA108, Merismopedia CENA106, Leptolyngbya CENA103, Leptolyngbya CENA112, Limnothrix CENA109, and Limnothrix CENA110), and for wastewater samples collected from raw influent (3.70 mu g microcystins/l) and treated effluent (3.74 mu g microcystins/l) in summer. Our findings indicate that toxic cyanobacteria in WSP systems are of concern, since the treated effluent containing cyanotoxins will be discharged into rivers, irrigation channels, estuaries, or reservoirs, and can affect human and animal health.

Porous alumina-spinel ceramics for high temperature applications

In order to reduce energy costs, high-temperature insulation porous refractory ceramics have been subjected to increasing demands. Among the techniques used to produce these materials (such as the addition of foaming agents and organic compounds), the pore generation via phase transformation presents key aspects, such as easy processing and the absence of toxic volatiles. In this study, this technique was applied to produce porous ceramics by decomposing an aluminum magnesium hydro-carbonate known as hydrotalcite (Mg(6)Al(2)(CO(3))(OH)(16)center dot 4H(2)O). It was found out that by using this complex compound, a large fraction of pores can be generated and kept at high temperatures (above 1300 degrees C) due to the in situ formation of spinel-like phases (MgAl(2)O(4)). (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Thermally activated peroxydisulfate in the presence of additives: A clean method for the degradation of pollutants

The kinetics and mechanism of the thermal activation of peroxydisulfate, in the temperature range from 60 to 80 degrees C, was investigated in the presence and absence of sodium formate as an additive to turn the oxidizing capacity of the reaction mixture into a reductive one. Trichloroacetic acid, TCA, whose degradation by a reductive mechanism is well reported in the literature, was used as a probe. The chemistry of thermally activated peroxydisulfate is described by a reaction scheme involving free radical generation. The proposed mechanism is evaluated by a computer simulation of the concentration profiles obtained under different experimental conditions. In the presence of formate, SO(4)(center dot-) radicals yield CO(2)(center dot-), which are the main species available for degrading TCA. Under the latter conditions, TCA is more efficiently depleted than in the absence of formate, but otherwise identical conditions of temperature and [S(2)O(8)(2-)]. We therefore conclude that activated peroxydisulfate in the presence of formate as an additive is a convenient method for the mineralization of substrates that are refractory to oxidation. such as perchlorinated hydrocarbons and TCA. This method has the advantage that leaves no toxic residues. (C) 2009 Elsevier Ltd. All rights reserved.

Probing Individual Quantum Dots: Noise in Self-Assembled Systems

In this work we explore the noise characteristics in lithographically-defined two terminal devices containing self-assembled InAs/InP quantum dots. The experimental ensemble of InAs dots show random telegraph noise (RTN) with tuneable relative amplitude-up to 150%-in well defined temperature and source-drain applied voltage ranges. Our numerical simulation indicates that the RTN signature correlates with a very low number of quantum dots acting as effective charge storage centres in the structure for a given applied voltage. The modulation in relative amplitude variation can thus be associated to the altered electrostatic potential profile around such centres and enhanced carrier scattering provided by a charged dot.

On state representations of nonlinear implicit systems

This work considers a semi-implicit system A, that is, a pair (S, y), where S is an explicit system described by a state representation (x)over dot(t) = f(t, x(t), u(t)), where x(t) is an element of R(n) and u(t) is an element of R(m), which is subject to a set of algebraic constraints y(t) = h(t, x(t), u(t)) = 0, where y(t) is an element of R(l). An input candidate is a set of functions v = (v(1),.... v(s)), which may depend on time t, on x, and on u and its derivatives up to a Finite order. The problem of finding a (local) proper state representation (z)over dot = g(t, z, v) with input v for the implicit system Delta is studied in this article. The main result shows necessary and sufficient conditions for the solution of this problem, under mild assumptions on the class of admissible state representations of Delta. These solvability conditions rely on an integrability test that is computed from the explicit system S. The approach of this article is the infinite-dimensional differential geometric setting of Fliess, Levine, Martin, and Rouchon (1999) (`A Lie-Backlund Approach to Equivalence and Flatness of Nonlinear Systems`, IEEE Transactions on Automatic Control, 44(5), (922-937)).

Modeling technique for honeycomb FRP deck bridges via finite elements

Honeycomb structures have been used in different engineering fields. In civil engineering, honeycomb fiber-reinforced polymer (FRP) structures have been used as bridge decks to rehabilitate highway bridges in the United States. In this work, a simplified finite-element modeling technique for honeycomb FRP bridge decks is presented. The motivation is the combination of the complex geometry of honeycomb FRP decks and computational limits, which may prevent modeling of these decks in detail. The results from static and modal analyses indicate that the proposed modeling technique provides a viable tool for modeling the complex geometry of honeycomb FRP bridge decks. The modeling of other bridge components (e.g., steel girders, steel guardrails, deck-to-girder connections, and pier supports) is also presented in this work.

Meat quality of broilers from different rearing systems

Color, pH, shear force, water-holding capacity, chemical composition, cholesterol content, and fatty acid profile from conventional, free-range and alternative broiler breast meat were determined in order to evaluate differences in the quality of broiler meat produced under different systems. Broilers reared in a conventional system had the highest lipid content (1.3%) but lower proportions of polyunsaturated (17.3%) and omega-3 fatty acids (0.3%) (p<0.05) compared to free-range and alternative broilers. On the other hand, free-range broilers had a lower cholesterol content (48.6 mg center dot 100 g(-1)) and lower pH (5.7 1) while broilers raised in an alternative system had a higher shear force (2.33 kgf) and lower yellowness value (b* value = 3.15) when compared to the other rearing systems (p<0.05).

Use of Sugar Cane Vinasse to Mitigate Aluminum Toxicity to Saccharomyces cerevisiae

Owing to its toxicity, aluminum (Al), which is one of the most abundant metals, inhibits the productivity of many cultures and affects the microbial metabolism. The aim of this work was to investigate the capacity of sugar cane vinasse to mitigate the adverse effects of Al on cell growth, viability, and budding, as the likely result of possible chelating action. For this purpose, Fleischmann`s yeast (Saccharomyces cerevisiae) was used in growth tests performed in 125-mL Erlenmeyer flasks containing 30 mL of YED medium (5.0 g/L yeast extract plus 20 g/L glucose) supplemented with the selected amounts of either vinasse or Al in the form of AlCl(3) center dot A H(2)O. Without vinasse, the addition of increasing levels of Al up to 54 mg/L reduced the specific growth rate by 18%, whereas no significant reduction was observed in its presence. The toxic effect of Al on S. cerevisiae growth and the mitigating effect of sugar cane vinasse were quantified by the exponential model of Ciftci et al. (Biotechnol Bioeng 25:2007-2023, 1983). The cell viability decreased from 97.7% at the start to 84.0% at the end of runs without vinasse and to 92.3% with vinasse. On the other hand, the cell budding increased from 7.62% at the start to 8.84% at the end of runs without vinasse and to 17.8% with vinasse. These results demonstrate the ability of this raw material to stimulate cell growth and mitigate the toxic effect of Al.

Tree-ring characterization of Araucaria columnaris Hook and its applicability as a lead indicator in environmental monitoring

Tree-rings have frequently been used for dating of trees and to determine annual growth increments and forest dynamics, but little is known in tropical conditions about their utilization for environmental monitoring. This paper presents the results of Araucaria columnaris tree-ring characterization by wood anatomy and X-ray densitometric analysis and the determination of Pb concentration. Core samples from twelve araucaria trees were extracted from two sites exposed to air pollution due to intense traffic of vehicles and industrial activities. The tree-rings distinctly presented radial variation in early-latewood thickness and density, and characteristics of juvenile and mature wood. Anatomical and X-ray densitometric analysis were useful to delimit the tree-ring boundaries and to date the tree-rings, as well as to prove the annual formation. The lead concentration in annual araucaria tree-rings, analyzed with graphite furnace atomic absorption spectrometry, indicated the seasonal presence of the heavy metal in the environment during the 30 years studied, although the Pb did not affect tree growth. (c) 2008 Elsevier GmbH. All rights reserved.

Banana fiber craftwork in the perspective of multifunctionality in quilombola communities

This study pursued an analysis of a modality of craftwork activity developed as an alternative for occupation and income using banana crop wastes. It is the banana fiber craftwork. The experience was developed in quilombola communities in the region of Vale do Ribeira, S (a) over tildeo Paulo State, Brazil. The correlation between the craftwork and other activities used as a source of income, like organic banana and other land crops, and rural tourism, was established. Using multifunctionality as a reference, it was intended to focus on the craftwork. activity within the dynamics of rural families in their territories, considering the economic, social, cultural and environmental issues involved in the quilombola`s activities. This permitted the evaluation of their contributions to the maintainance of the life conditions of these communities.

Annual and polyetic progression of citrus canker on trees protected with copper sprays

The effects of copper sprays on annual and polyetic progress of citrus canker, caused by Xanthomonas citri subsp. citri, in the presence of the Asian citrus leafminer (Phyllocnistis citrella), were evaluated in a study conducted in a commercial orchard in northwest Parana state, Brazil, where citrus canker is endemic. Nonlinear monomolecular, logistic and Gompertz models were fitted to monthly disease incidence data (proportion of leaves with symptoms) for each treatment for three seasons. The logistic model provided the best estimate of disease progress for all years and treatments evaluated and logistic parameter estimates were used to describe polyetic disease dynamics. Although citrus canker incidence increased during each of the seasons studied, it decreased over the whole study period, more so in copper-treated trees than in water-sprayed controls. Copper treatment reduced disease incidence compared with controls in every year, especially 2004-2005, when incidence was ca. 10-fold higher in controls than in treated plots (estimated asymptote values 0 center dot 82 and 0 center dot 07, respectively). Copper treatment also reduced estimated initial disease incidence and epidemic growth rates every year.

Liberibacters associated with orange jasmine in Brazil: incidence in urban areas and relatedness to citrus liberibacters

Two surveys (2005/2006 and 2009) were conducted in the state of Sao Paulo, Brazil, to investigate the incidence of `Candidatus Liberibacter asiaticus` and `Ca. L. americanus`, two liberibacters associated with citrus huanglongbing (HLB) disease and both transmitted by Diaphorina citri, in orange jasmine (Murraya exotica), a widespread ornamental tree in cities and villages. The graft-transmissibility of the two species, and their DNA relatedness to citrus-associated liberibacters, were also investigated. Quantitative PCR was applied to PCR-positive orange jasmine and HLB-positive citrus growing in backyards and orchards to assess their inoculum source potentials. Liberibacters were detected in 91 of 786 sampled orange jasmine plants in 10 of 76 sampled locations. PCR-positive trees exhibited yellow shoots and/or dieback symptoms indistinguishable from those on PCR-negative trees. `Candidatus Liberibacter americanus` was more common in 2005/2006 (96 center dot 6%) and `Ca. L. asiaticus` in 2009 (84 center dot 8%). rplJ nucleotide sequences were identical within all populations of either species. Graft transmission succeeded only in homologous host combinations, including `Ca. L. americanus` (2/10) from/to orange jasmine and `Ca. L. americanus` (5/18) and `Ca. L. asiaticus` (5/9) from/to citrus. Symptoms were mild and developed less rapidly in orange jasmine than in citrus, probably as a result of lower liberibacter multiplication rates. Respective titres of `Ca. L. americanus` and `Ca. L. asiaticus` in orange jasmine averaged 4 center dot 3 and 3 center dot 0 log cells g-1 tissue, compared with 5 center dot 5 and 7 center dot 3 in citrus. The results indicate that orange jasmine does not favour liberibacter multiplication as much as citrus. However, its importance in HLB epidemics should not be underestimated as it is a preferred host of D. citri and is not under any strict tree-eradication programme or measures for insect control.

TESA-blot for the diagnosis of Chagas disease in dogs from co-endemic regions for Trypanosoma cruzi, Trypanosoma evansi and Leishmania chagasi

We standardized serodiagnosis of dogs infected with Trypanosoma cruzi using TESA (trypomastigote excreted-secreted antigen)-blot developed for human Chagas disease. TESA-blot showed 100% sensitivity and specificity. In contrast, ELISA using TESA (TESA-ELISA) or epimastigotes (epi-ELISA) as antigen yielded 100% sensitivity but specificity of 94.1% and 49.4%, respectively. When used in field studies in an endemic region for Chagas disease, visceral leishmaniasis and Trypanosoma evansi (Mato Grosso do Sul state, Central Brazil), positivities were 9.3% for TESA-blot, 10.7% for TESA-ELISA and 32% for epi-ELISA. Dogs from a non-endemic region for these infections (Rondonia state, western Amazonia) where T cruzi is enzootic showed positivity of 4.5% for TESA-blot and epi-ELISA and 6.8% for TESA-ELISA. Sera from urban dogs from Santos, Sao Paulo, where these diseases are absent, yielded negative results. TESA-blot was the only method that distinguished dogs infected with T cruzi from those infected with Leishmania chagasi and/or Trypanosoma evansi. (C) 2009 Published by Elsevier B.V.

Nitrogen and Sulfur Fertilization and Dynamics in a Brazilian Entisol under Pasture

Nutrient dynamics in tropical soils sustaining forage grasses are still poorly understood. We conducted a study to evaluate the effect of combined N and S fertilizer rates on the growth of `Marandu` palisade grass [Brachiaria brizantha (Hochst. ex A. Rich.) Stapf], uptake of these elements from the soil by plants, soil organic matter concentration, soil pH, and the mineral and organic fractions of N and S in an Entisol. Combinations of five N rates (0, 100, 200, 300, and 400 g N m(-3)) with five S rates (0, 10, 20, 30, and 40 g S m(-3)) were evaluated in a partial 5 x 5 factorial in a pot experiment, with and without plants. Nitrogen and S were supplied as NH(4)NO(3) and CaSO(4)center dot 2H(2)O, respectively. The N addition in excess did not enhance the palisade grass production due to low plant-available Sin the soil. The supply of low rates of S with N greatly improved the overall N uptake efficiency by the forage plant. The contents of total N, NO(3)(-)-N, and NH(4)(+)-N in the soil varied with N rate and with N uptake by the plants. The association of palisade grass with S fertilization increased the ester-bonded S fraction in the soil. The results suggest that soil residual S could be a potential source of S for plants. Proper N and S fertilizer rates promoted increased grass production due to increased uptake of these nutrients and the dynamics of the organic N and S fractions and mineral fractions in this tropical soil.