Ambiental volatile organic compounds in the megacity of São Paulo

In order to characterize the composition of the main urban air organic compounds in the megacity of Sao Paulo, analysis of samples collected during the winter of 2003 downtown was carried out. The samplings were performed on the roof of a building in the commercial center of São Paulo. Hydrocarbons and carbonyls compounds were collected on August 4, 5 and 6. Comparing to previous data, the concentration of hydrocarbons presented no decrease in the concentration, except for the aldehydes, which decreased when compared to previous data. Among the HCs species analyzed, the highest concentrations observed were those of toluene (7.5 ± 3.4 ppbv), n-decane (3.2 ± 2.0 ppbv), benzene (2.7 ± 1.4 ppbv) and 1,3,5-trimethylbenzene (2.2 ± 1.5 ppbv).

Screening process for activity determination of conductive oxide electrodes for organic oxidation

A modified method for the calculation of the normalized faradaic charge (q fN) is proposed. The method involves the simulation of an oxidation process, by cyclic voltammetry, by employing potentials in the oxygen evolution reaction region. The method is applicable to organic species whose oxidation is not manifested by a defined oxidation peak at conductive oxide electrodes. The variation of q fN for electrodes of nominal composition Ti/RuX Sn1-X O2 (x = 0.3, 0.2 and 0.1), Ti/Ir0.3Ti0.7O2 and Ti/Ru0.3Ti0.7O2 in the presence of various concentrations of formaldehyde was analyzed. It was observed that electrodes containing SnO2 are the most active for formaldehyde oxidation. Subsequently, in order to test the validity of the proposed model, galvanostatic electrolyses (40 mA cm-2) of two different formaldehyde concentrations (0.10 and 0.01 mol dm-3) were performed. The results are in agreement with the proposed model and indicate that this new method can be used to determine the relative activity of conductive oxide electrodes. In agreement with previous studies, it can be concluded that not only the nature of the electrode material, but also the organic species in solution and its concentration are important factors to be considered in the oxidation of organic compounds.

Development of a flow through photo-reactor to study degradation of organic compounds by Sequential Injection Analysis (SIA)

This work describes a photo-reactor to perform in line degradation of organic compounds by photo-Fenton reaction using Sequential Injection Analysis (SIA) system. A copper phthalocyanine-3,4',4²,4²¢-tetrasulfonic acid tetrasodium salt dye solution was used as a model compound for the phthalocyanine family, whose pigments have a large use in automotive coatings industry. Based on preliminary tests, 97% of color removal was obtained from a solution containing 20 µmol L-1 of this dye.

Aeromonas presence in drinking water from collective reservoirs and wells in peri-urban area in Brazil

Aeromonas genus is considered an emerging pathogen and its presence in drinking water supplies is a reason to public health concern. This study investigated the occurrence of Aeromonas in samples from collective reservoirs and wells used as drinking water sources in a peri-urban area. A total of 35 water samples were collected from collective reservoirs and 32 from wells bimonthly, from September 2007 to September 2008. Aeromonas spp determination was carried out using a Multiple-Tube Technique. Samples were inoculated into alkaline peptone water and the superficial film formed was transferred to blood agar plates amended with ampicillin. Typical Aeromonas colonies were submitted to a biochemical screening and then to biochemical tests for species differentiation. Aeromonas was detected in 13 (19%) of the 69 samples examined (6 from collective reservoirs and 7 from wells). Concentrations of Aeromonas in collective reservoirs ranged from <0.3 to 1.2 x10²MPN/100mL and, in wells, from <0.3 to 2.4 x10²MPN/100mL. The most frequent specie in the collective reservoir samples was Aeromonas spp (68%), followed by A. encheleia (14%) and A. allosaccharophila (8%) and A. hydrophila (8%). Aeromonas spp (87%) was the most frequent specie isolated from well samples, followed by A. allosacchariphila (8%), A. encheleia (2%) and A. jandaei (5%). These data show the presence and diversity of Aeromonas genus in the samples analyzed and highlight that its presence in drinking water poses a significant public health concern.

Digestible lysine and organic zinc for male broiler from 1 to 11 days of age: performance and body composition

This study evaluated levels of digestible lysine and organic zinc for male Ross strain broilers from 1 to 11 days of age. It was used 1,050 chicks distributed in randomized block design, in 5 × 2 factorial scheme, with seven repetitions of 15 birds per experimental unit. The dietary concentrations of digestible lysine were 0.90; 1.00; 1.10; 1.20; and 1.40% combined with 43 and 253 ppm zinc chelate. The diets contained 2,965 ± 18 kcal/kg of apparent metabolizable energy (AME) and 21.48 ± 0.18% of CP. It was determined chemical composition, protein, lipid, mineral and water depositions on carcass and empty body. There was no interaction among the factors digestible lysine and organic zinc. Effect of zinc concentration increase was observed on greatest deposition of body fat, indicating that there is interference in lipid metabolism of the birds in the studied phase. The most pronounced effects resulted from the dietary inclusion of lysine. There was a linear effect on reconstituted body weight as a response to the increase of dietary lysine, which suggests equal or superior requirement to the greatest studied level. However, the deposition of water and protein on the carcass had a quadratic increase, characterizing higher muscle mass accumulation up to the levels 1.25 and 1.27 of this amino acid in the diet. Considering the studied strain, broiler chickens from the first to the 11th days of age require 1.28 ± 0.01% of digestible lysine, according to the deposition of muscle mass.

Carbon Stocks and Isotopic Composition of the Organic Matter in Soils Covered by Native Vegetation and Pasture in Sorocaba, SP, Brazil

Land cover change constitutes one of main way of alteration of soil organic matter in both quantitative and qualitative terms. The goal of this study was to compare the carbon stock and the isotopic signature of the organic matter in the soil of areas with different land use,covered with forest and grass (pasture). The study area is located at Sorocaba, SP, Brazil. Using un-deformed soil samples, we measured the carbon content and bulk density. The isotopic signature of soil carbon was determined through the analysis of isotopic ratio (12)C/(13)C. The pasture soil stocks 48% less carbon than the soil covered by natural forest. The isotopic signature indicated that 42.2% of organic matter of the soil covered by pasture is originated from grasses. This characterizes a highly degradation of organic matter in the environment, both quantitatively and qualitatively. Hence, some guidelines of recuperation are described in order to restore the soil organic matter, structure and porosity.

Students' collective knowledge construction in the virtual learning environment ""ToLigado - your school interactive newspaper""

Introduction. The ToLigado Project - Your School Interactive Newspaper is an interactive virtual learning environment conceived, developed, implemented and supported by researchers at the School of the Future Research Laboratory of the University of Sao Paulo, Brazil. Method. This virtual learning environment aims to motivate trans-disciplinary research among public school students and teachers in 2,931 schools equipped with Internet-access computer rooms. Within this virtual community, students produce collective multimedia research documents that are immediately published in the portal. The project also aims to increase students' autonomy for research, collaborative work and Web authorship. Main sections of the portal are presented and described. Results. Partial results of the first two years' implementation are presented and indicate a strong motivation among students to produce knowledge despite the fragile hardware and software infrastructure at the time. Discussion. In this new environment, students should be seen as 'knowledge architects' and teachers as facilitators, or 'curiosity managers'. The ToLigado portal may constitute a repository for future studies regarding student attitudes in virtual learning environments, students' behaviour as 'authors', Web authorship involving collective knowledge production, teachers' behaviour as facilitators, and virtual learning environments as digital repositories of students' knowledge construction and social capital in virtual learning communities.

Haptic Stabilization of Posture in Adults With Intellectual Disabilities Using a Nonrigid Tool

This study assessed the effects of haptic information on the postural control systems of individuals with intellectual disabilities (ID), through the use of a nonrigid tool that we call the ""anchor system"" (e.g., ropes attached to graduated weights that rest on the floor). Eleven participants with ID were asked to stand, blindfolded, on a balance beam placed at two heights (10 and 20 cm), for 30 s, while using the anchor system at two weights. The lighter anchor weight appeared to improve the individuals' balance in contrast to a control task condition; therefore, we concluded that haptic sensitivity was more significant in helping to orient the body than was the anchor's mechanical support alone.

Biochemical characterization of pulp of banana fruit: measurement of soluble sugars, organic acids, free ACC and in vitro ACC oxidase

Introduction. We present some protocols aiming at partially characterizing banana fruit quality through measurement of some key biochemical parameters. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials and the steps necessary for achieving four protocols making it possible to measure sugar, organic acids and free ACC contents, and in vitro ACC oxidase activity. Results. Standard results obtained by using the protocols described are presented in the figures.

Increased CLA content in organic milk fermented by bifidobacteria or yoghurt cultures

This study investigates the kinetics of acidification, fatty acid (FA) profile and conjugated linoleic acid (CLA, C18:2 c9, t11) content in fermented milks prepared from organic and conventional milk. Fermented milks were manufactured with five mixed cultures: four different strains of Bifidobacterium animalis subsp. lactis (BL04, B94, BB12 and HN019) and Lactobacillus delbrueckii subsp. bulgaricus LB340, in co-culture with Streptococcus thermophilus TA040. The composition of milk was evaluated, and the kinetics of acidification was followed by continuous pH measurement using the Cinac system. The profile of FA, including CLA, was analyzed by gas chromatography. The chemical composition of conventional and organic milk was similar, with the exception of protein and Fe, the concentrations of which were higher in the organic milk. The rate of acidification was significantly influenced by the type of milk and the bacterial strain used. Co-cultures St-HN019 and St-BB12 showed higher maximal acidification rates in both milks. Final counts of S. thermophilus (9.0-10.1 log(10) colony forming units (CFU) . mL(-1), L)actobacillus bulgaricus (8.2-8.5 log(10) CFU . mL(-1)) and B. animalis subsp. lactis strains (8.3-9.3 log(10) CFU . mL(-1)) did not differ significantly in either milk. Unexpectedly, all fermented organic milks contained significantly higher amounts of CLA than the same milk before fermentation, whereas CLA amounts did not change during fermentation of conventional milk. Regardless of the type of milk, CLA was found to be significantly positively correlated with trans-vaccenic acid and negatively correlated with linoleic acid. Moreover, the CLA contents were significantly higher in fermented milks showing shorter fermentation times.

Simplified Mathematical Model for an Anaerobic Sequencing Batch Biofilm Reactor Treating Lipid-Rich Wastewater Subject to Rising Organic Loading Rates

This study proposes a simplified mathematical model to describe the processes occurring in an anaerobic sequencing batch biofilm reactor (ASBBR) treating lipid-rich wastewater. The reactor, subjected to rising organic loading rates, contained biomass immobilized cubic polyurethane foam matrices, and was operated at 32 degrees C +/- 2 degrees C, using 24-h batch cycles. In the adaptation period, the reactor was fed with synthetic substrate for 46 days and was operated without agitation. Whereas agitation was raised to 500 rpm, the organic loading rate (OLR) rose from 0.3 g chemical oxygen demand (COD) . L(-1) . day(-1) to 1.2 g COD . L(-1) . day(-1). The ASBBR was fed fat-rich wastewater (dairy wastewater), in an operation period lasting for 116 days, during which four operational conditions (OCs) were tested: 1.1 +/- 0.2 g COD . L(-1) . day(-1) (OC1), 4.5 +/- 0.4 g COD . L(-1) . day(-1) (OC2), 8.0 +/- 0.8 g COD . L(-1) . day(-1) (OC3), and 12.1 +/- 2.4 g COD . L(-1) . day(-1) (OC4). The bicarbonate alkalinity (BA)/COD supplementation ratio was 1:1 at OC1, 1:2 at OC2, and 1:3 at OC3 and OC4. Total COD removal efficiencies were higher than 90%, with a constant production of bicarbonate alkalinity, in all OCs tested. After the process reached stability, temporal profiles of substrate consumption were obtained. Based on these experimental data a simplified first-order model was fit, making possible the inference of kinetic parameters. A simplified mathematical model correlating soluble COD with volatile fatty acids (VFA) was also proposed, and through it the consumption rates of intermediate products as propionic and acetic acid were inferred. Results showed that the microbial consortium worked properly and high efficiencies were obtained, even with high initial substrate concentrations, which led to the accumulation of intermediate metabolites and caused low specific consumption rates.

Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC 2002 biomass burning experiment in Rondonia, Brazil: sources and source processes, time series, diel variations and size distributions

Measurements of polar organic marker compounds were performed on aerosols that were collected at a pasture site in the Amazon basin (Rondonia, Brazil) using a high-volume dichotomous sampler (HVDS) and a Micro-Orifice Uniform Deposit Impactor (MOUDI) within the framework of the 2002 LBA-SMOCC (Large-Scale Biosphere Atmosphere Experiment in Amazonia - Smoke Aerosols, Clouds, Rainfall, and Climate: Aerosols From Biomass Burning Perturb Global and Regional Climate) campaign. The campaign spanned the late dry season (biomass burning), a transition period, and the onset of the wet season (clean conditions). In the present study a more detailed discussion is presented compared to previous reports on the behavior of selected polar marker compounds, including levoglucosan, malic acid, isoprene secondary organic aerosol (SOA) tracers and tracers for fungal spores. The tracer data are discussed taking into account new insights that recently became available into their stability and/or aerosol formation processes. During all three periods, levoglucosan was the most dominant identified organic species in the PM(2.5) size fraction of the HVDS samples. In the dry period levoglucosan reached concentrations of up to 7.5 mu g m(-3) and exhibited diel variations with a nighttime prevalence. It was closely associated with the PM mass in the size-segregated samples and was mainly present in the fine mode, except during the wet period where it peaked in the coarse mode. Isoprene SOA tracers showed an average concentration of 250 ng m(-3) during the dry period versus 157 ng m(-3) during the transition period and 52 ng m(-3) during the wet period. Malic acid and the 2-methyltetrols exhibited a different size distribution pattern, which is consistent with different aerosol formation processes (i.e., gas-to-particle partitioning in the case of malic acid and heterogeneous formation from gas-phase precursors in the case of the 2-methyltetrols). The 2-methyltetrols were mainly associated with the fine mode during all periods, while malic acid was prevalent in the fine mode only during the dry and transition periods, and dominant in the coarse mode during the wet period. The sum of the fungal spore tracers arabitol, mannitol, and erythritol in the PM(2.5) fraction of the HVDS samples during the dry, transition, and wet periods was, on average, 54 ng m(-3), 34 ng m(-3), and 27 ng m(-3), respectively, and revealed minor day/night variation. The mass size distributions of arabitol and mannitol during all periods showed similar patterns and an association with the coarse mode, consistent with their primary origin. The results show that even under the heavy smoke conditions of the dry period a natural background with contributions from bioaerosols and isoprene SOA can be revealed. The enhancement in isoprene SOA in the dry season is mainly attributed to an increased acidity of the aerosols, increased NO(x) concentrations and a decreased wet deposition.

Finite-size particles, advection, and chaos: A collective phenomenon of intermittent bursting

We consider finite-size particles colliding elastically, advected by a chaotic flow. The collisionless dynamics has a quasiperiodic attractor and particles are advected towards this attractor. We show in this work that the collisions have dramatic effects in the system's dynamics, giving rise to collective phenomena not found in the one-particle dynamics. In particular, the collisions induce a kind of instability, in which particles abruptly spread out from the vicinity of the attractor, reaching the neighborhood of a coexisting chaotic saddle, in an autoexcitable regime. This saddle, not present in the dynamics of a single particle, emerges due to the collective particle interaction. We argue that this phenomenon is general for advected, interacting particles in chaotic flows.

On molecular chirality within naturally occurring secondary organic aerosol particles from the central Amazon Basin

In this perspectives article, we reflect upon the existence of chirality in atmospheric aerosol particles. We then show that organic particles collected at a field site in the central Amazon Basin under pristine background conditions during the wet and dry seasons consist of chiral secondary organic material. We show how the chiral response from the aerosol particles can be imaged directly without the need for sample dissolution, solvent extraction, or sample preconcentration. By comparing the chiral-response images with optical images, we show that chiral responses always originate from particles on the filter, but not all aerosol particles produce chiral signals. The intensity of the chiral signal produced by the size resolved particles strongly indicates the presence of chiral secondary organic material in the particle. Finally, we discuss the implications of our findings on chiral atmospheric aerosol particles in terms of climate-related properties and source apportionment.

Organic molecule assembled between carbon nanotubes: A highly efficient switch device

We report a highly efficient switch built from an organic molecule assembled between single-wall carbon nanotube electrodes. We theoretically show that changes in the distance between the electrodes alter the molecular conformation within the gap, affecting in a dramatic way the electronic and charge transport properties, with an on/off ratio larger than 300. This opens up the perspective of combining molecular electronics with carbon nanotubes, bringing great possibilities for the design of nanodevices.