Characterization of Cuban and Brazilian natural zeolites by photoacoustic spectroscopy and electron paramagnetic resonance.

This report describes the photoacoustic and electron paramagnetic resonance investigations of Brazilian and Cuban zeolites. Photoacoustic optical absorption measurements indicate the presence of iron (Fe3+) ions with their respective transition bands for both zeolites. Two species of manganese (Mn2+ and Mn3+) were identified in the Cuban sample and the electronic transitions assigned. Iron and manganese ions were confirmed through nonradiative relaxation (τ) and characteristic diffusion (τß) times evaluation, whose values were found to be τBRA = 5.40 ms, τCUB = 4.60 ms, τßBRA = 387 µs and τßCUB = 305 µs. Crystal field (Dq-BRA/Dq-CUB = 1048 cm-1/945 cm-1) plus Racah (B-BRA/B-CUB = 457 cm-1/813 cm-1 and C-BRA/C-CUB = 3655 cm-1/2496 cm-1) parameters were assessed as well. Paramagnetic resonance corroborated Fe3+ ions present in the Brazilian zeolite occupying sites showing axial and/or rhombic symmetry distortions. For the Cuban sample, results reveal the characteristic hyperfine sextet lines of Mn2+ overlapping the Fe3+ line. Values of Landé factor and isotropic hyperfine splitting constant were found to be 2.0 and 9.7 mT, respectively. This tells us that the Mn2+ lies in octahedral symmetry probably replacing calcium ions and point towards an ionic bonding character of the Mn2+ and its surroundings.

Pollutant gas and particulate material emissions in ethanol production in Brazil: social and environmental impacts.

The replacement of fossil-based fuels by renewable fuels (biofuels) was proposed in the IPCC report, as an alternative to reduce greenhouse gas emission and reach out to a low-carbon economy. On this perspective, the Brazilian government had implemented a renewable energy program based on the use of ethanol in the transport sector. This work evaluates the scenario of pollutant gas emissions and particulate material that comes from the biomass burning process involved in ethanol production cycle, in the city of Campos dos Goytacazes, Brazil. The gases and particulate material emitted by sugarcane and bagasse burning processes-the last one in energy co-generation mills-were analyzed. A laboratory-controlled burning of both samples was realized in an oven with temperature ramp from 250 to 400 °C, at a regular rate of 50 °C. The gas samples were collected directly from the oven's exhaust pipe. The particulates obtained were the residual material taken out of the burned samples: a powder with the aspect of soot. A photoacoustic spectroscopy system coupled with quantum cascade laser and electrochemical analyzers was used to measure the emission of polluting gases such as N2O, CO2, CO, NOx (NO, NO2), and SO2 in ppmv range. Fluorescent X-ray spectrometry was applied to evaluate the chemical composition of particulate material, enabling the identification of elements such as Si, Al, Ca, K, Fe, S, P, Ti, Mn, Cu, Zn, Sc, V, Cu, and Sr.

Prevalence of rhinitis among 6 and 7-year old students in Fortaleza.

OBJECTIVE: to evaluate the prevalence of rhinitis symptoms among 6 and 7-year old schoolchildren in Fortaleza, Brazil. METHODS: a cross-sectional study using the rhinitis module of the ISAAC (International Study of Asthma and Allergies in Childhood) questionnaire. The sample included 2,020 students from public and private schools, in 2010. RESULTS: the prevalence of cumulative rhinitis, active rhinitis, allergic rhinoconjunctivitis and physician-diagnosed rhinitis was 49.9%, 42%, 15.4% and 28.1%, respectively, being significantly more prevalent among private school students (OR = 0.55, 95CI: 0.46 - 0.66, p < 0.001; OR = 0.50, 95CI: 0.41 - 0.60, p < 0.001; OR = 0.67, 95CI: 0.52 - 0.85, p < 0.001; OR = 0.15, 95CI: 0.12 - 0.19, p < 0.001, respectively), without differences between genders. Interference with daily activities was reported by 25.3%, while 5.7% reported to be moderately or severely affected, without a difference between genders. CONCLUSION: the prevalence of rhinitis symptoms and associated morbidity among 6-7-year old schoolchildren in Fortaleza was above the Brazilian average, with predominance among private school students, without difference between genders. It was observed that rhinitis was underdiagnosed in this population.

Prevalence of rhinitis among 6 and 7-year old students in Fortaleza / Prevalência de rinite em escolares de 6 e 7 anos de Fortaleza

Objective: to evaluate the prevalence of rhinitis symptoms among 6 and 7-year old schoolchildren in Fortaleza, Brazil. Methods: a cross-sectional study using the rhinitis module of the ISAAC (International Study of Asthma and Allergies in Childhood) questionnaire. The sample included 2,020 students from public and private schools, in 2010. Results: the prevalence of cumulative rhinitis, active rhinitis, allergic rhinoconjunctivitis and physician-diagnosed rhinitis was 49.9%, 42%, 15.4% and 28.1%, respectively, being significantly more prevalent among private school students (OR = 0.55, 95CI: 0.46 - 0.66, p < 0.001; OR = 0.50, 95CI: 0.41 - 0.60, p < 0.001; OR = 0.67, 95CI: 0.52 - 0.85, p < 0.001; OR = 0.15, 95CI: 0.12 - 0.19, p < 0.001, respectively), without differences between genders. Interference with daily activities was reported by 25.3%, while 5.7% reported to be moderately or severely affected, without a difference between genders. Conclusion: the prevalence of rhinitis symptoms and associated morbidity among 6-7-year old schoolchildren in Fortaleza was above the Brazilian average, with predominance among private school students, without difference between genders. It was observed that rhinitis was underdiagnosed in this population. .

Objetivo: avaliar a prevalência de sintomas de rinite em crianças de 6 e 7 anos de idade, em Fortaleza. Métodos: foi aplicado o questionário ISAAC (International Study of Asthma and Allergies in Childhood), módulo rinite, em estudo de desenho transversal de base populacional, com amostragem probabilística de 2.020 escolares de escolas públicas e privadas, em 2010. Resultados: a prevalência de rinite cumulativa, rinite ativa, rinoconjuntivite alérgica e rinite diagnosticada foi, respectivamente, 49,9, 42, 15,4 e 28,1%, com predomínio de forma significativa entre as crianças das escolas particulares (RC = 0,55, IC95%: 0,46 a 0,66, p < 0,001; RC = 0,50, IC95%: 0,41 a 0,60, p < 0,001; RC = 0,67, IC95%: 0,52 a 0,85, p < 0,001; RC = 0,15, IC95%: 0,12 a 0,19, p < 0,001, respectivamente), e sem diferença entre os gêneros. Interferência dos sintomas com as atividades diárias foi relatada por 25,3% dos pesquisados, e 5,7% relataram ser moderada ou intensamente afetados, sem diferença entre os gêneros. Conclusão: a prevalência de sintomas de rinite e da morbidade associada, entre crianças de 6 e 7 anos de idade, em Fortaleza, mostrou-se acima da média nacional, com predomínio no grupo das escolas privadas, e sem diferença entre os gêneros. Observou-se também que rinite é subdiagnosticada entre as crianças de 6 e 7 anos de idade, em Fortaleza. .

Nutrient release by a Brazilian sedimentary zeolite

This report describes the characterization of a sedimentary occurrence from the Parnaíba Basin, Brazil, containing the zeolite stilbite intertwined with smectitic clay mineral. The head samples from different sites present a wide content range of the zeolitic phase - 15 percent to 50 percent. The use of simple separation techniques - conventional gravitic treatments - yields concentrates containing about 67 percent of the zeolitic component. Assays with the amendments of these concentrates with plant nutrients yield release rates matching those reported for similar commercial products.

São apresentadas as propriedades físico-químicas de uma ocorrência sedimentar da Bacia do Parnaíba, Brasil, da zeólita estilbita, agregada a uma argila esmectítica. As amostras de diferentes sítios apresentam uma ampla variação do mineral zeolítico: entre 15 por cento a 50 por cento. A utilização de espirais concentradoras foi suficiente para obtenção de concentrados contendo até 67 por cento do mineral. Ensaios laboratoriais do concentrado dopado com fertilizantes revelam taxas de liberação de nutrientes comparáveis aos obtidos com produtos comerciais similares.

Prevalência de sintomas de rinite em adolescentes de 13 e 14 anos avaliada pelo método ISAAC, na cidade de Fortaleza / Prevalence of rhinitis symptoms in 13 to 14-year old adolescents assessed by the method ISAAC, in the city of Fortaleza

Objetivo: Avaliar a prevalência de sintomas de rinite em escolares de 13 e 14 anos de Fortaleza. Métodos: Aplicou-se o questionário ISAAC (International Study of Asthma and Allergies in Childhood), módulo rinite, em estudo de desenho transversal de base populacional, com amostragem probabilística de 3.015 escolares, de escolas públicas e privadas, no período de 2006 a 2007. Resultados: A prevalência cumulativa de rinite, rinite ativa, rinoconjuntivite alérgica e rinite diagnosticada foi 56,7%, 43,2%, 18,7% e 20,2%, respectivamente. Sintomas de rinite e rinite diagnosticada predominaram de forma significativa no gênero feminino (RP = 1,29, IC95%: 1,20-1,38, p<0,001; RP = 1,27, IC95%: 1,19 - 1,35, P<0,001; RP=1,26, IC95%: 1,18 -1,36, p<0,001 e RP=1,14, IC95%: 1,05 - 1,22, p=0,001, respectivamente) e entre os adolescentes das escolas privadas (RP = 1,62, IC95%:1,43-1,87, p<0,001; RP = 1,71, IC95%: 1,52-1,92 , p<0,001; RP=1,59, IC95%: 1,41-1,80, p<0,001 e RP=1,97, IC95%: 1,76-2,20, p<0,001, respectivamente). Interferência dos sintomas com as atividades diárias foi relatada por 24% dos pesquisados, e 4,7% relataram ser moderada ou intensamente afetados, com predomínio no gênero feminino (RP:1,22, IC95%: 1,08 - 1,38, p=0,005). Conclusões: a prevalência de sintomas de rinite e da morbidade associada, entre adolescentes de 13 e 14 anos de Fortaleza, mostrou-se acima da média nacional, com predomínio no gênero feminino e no grupo das escolas privadas. A prevalência de sintomas de rinoconjuntivite alérgica foi semelhante à média nacional. Observou-se também que rinite é subdiagnosticada entre os adolescentes de Fortaleza.

Aim: To evaluate the prevalence of rhinitis symptoms among 13 to 14-year old schoolchidren from Fortaleza, Brazil. Methods: The cross-sectional study used the self-applied International Study of Asthma and Allergies in Childhood questionnaire. The sample included 3.015 students from public and private schools, from 2006 to 2007. Results: The prevalence of cumulative rhinitis, current rhinitis, rhinoconjunctivitis and diagnosed rhinitis was 56.7%, 43.2%, 18.7% and 20.2%, respectively. Rhinitis symptoms and diagnosed rhinitis were significantly more prevalent among females (PR = 1.29, CI95%: 1.20-1.38, p<0.001; PR = 1.27, CI95%: 1.19 - 1.35, p<0.001; PR=1.26, CI95%: 1.18--1.36, P<0.001 and PR=1.14, CI95%: 1.05 - 1.22, p=0.001, respectively), and private school students (PR = 1.62, CI95%: 1.43-1.87, p<0.001; PR = 1.71, CI95%: 1.52-1.92 , p<0.001; PR=1.59, CI95%: 1.41-1.80, p<0.001 e PR=1.97, CI95%: 1. 76-2.20, P<0.001, respectively). Interference with daily activities was reported by 24%, and 4.7% claimed to be moderately or severely affected, with females predominating over males (PR=1.22, CI95%: 1.08-1.38, p=0.005). Conclusions: The prevalence of rhinitis symptoms and associated morbidity among 13 to 14-year old schoolchidren from Fortaleza was above the Brazilian average, with predominance among females and private school students. The prevalence of allergic rhinoconjunctivitis symptoms was similar to the national average. It was observed that rhinitis was under diagnosed this population.

Effect of prolonged exposition to pulp mill effluents on the invasive aquatic plant Egeria densa and other primary producers: a mesocosm approach.

The recent disappearance of the aquatic plant Egeria densa, a Brazilian native invasive species, from a wetland in southern Chile prompted several efforts to unveil the origin of this phenomenon. Because these changes occurred by the time a newly built pulp mill started its operations in the area, a reasonable doubt for a cause-effect relationship is plausible. We implemented a mesocosm approach to directly evaluate the effect of treated pulp mill effluents (PMEs) on several growth-related parameters of E. densa as well as other primary producers. We hypothesize that effluent, at a dilution similar to that detected in the zone of the wetland where the negative environmental impacts were evident, has a significant negative effect on this aquatic plant as well as on other primary producers inside a mesocosm system. After a prolonged (months) exposure to both 0% PME with pure river water and a 4 to 5% (v/v) dilution of treated PME, no effect on E. densa was measured. Furthermore, plants exposed to effluent exhibited a significantly greater general growth rate. Coincidently, chlorophyll a concentration in the water column and periphyton biomass also changed over time, but without any pattern attributable to the effluent. Values of the autotrophic index obtained from the periphyton growth pattern did not suggest enrichment of the system with organic matter. Our results only refer to the direct effect of mill effluents on several biotic responses, but they represent an important advance toward generation of the scientific knowledge necessary to understand how the ecosystem functions while receiving this and other unquantified sources of water.

Photothermal gas analyzer for simultaneous measurements of thermal diffusivity and thermal effusivity.

In this paper, we describe a new, simple, and fast photothermal method for simultaneous measurements of two important gas thermal properties: thermal diffusivity and thermal effusivity. The method consists essentially in combining a photoacoustic cell and a thermal wave pyroelectric cell enclosed in a single compact gas analyzer. The photoacoustic cell is kept filled with synthetic air and sealed. The pyroelectric cell is also filled with synthetic air, and after some warm up time, the synthetic air is exchanged to the gas of interest. It is shown that the analysis of the transient and saturation signals of both photoacoustic and pyroelectric cells is capable of measuring the thermal properties with an accuracy of 3%. This particular capability of performing simultaneously the measurements of thermal diffusivity and thermal effusivity allows us to carry on the complete characterization of the thermal properties of gases.

Ammonia detection by using quantum-cascade laser photoacoustic spectroscopy.

A pulsed quantum-cascade distributed-feedback laser, temperature tunable from -41 degrees C to +31.6 degrees C, and a resonant differential photoacoustic detector are used to measure trace-gas concentrations to as low as 66 parts per 10(9) by volume (ppbv) ammonia at a low laser power of 2 mW. Good agreement between the experimental spectrum and the simulated HITRAN spectrum of NH3 is found in the spectral range between 1046 and 1052 cm(-1). A detection limit of 30 ppbv ammonia at a signal-to-noise ratio of 1 was obtained with the quantum-cascade laser (QCL) photoacoustic (PA) setup. Concentration changes of approximately 50 ppbv were detectable with this compact and versatile QCL-based PA detection system. The performance of the PA detector, characterized by the product of the incident laser power and the minimum detectable absorption coefficient, was 4.7 x 10-9 W cm(-1).