RESUMO O presente artigo avaliou a interferência da quantidade de defasagens utilizadas no resultado do valor-p associado à estatística utilizada no teste de Dickey-Fuller aumentado (ADF), bem como identificou algumas propriedades das séries estudadas que interferem em seu resultado. Foram realizados três experimentos com séries de diferentes amplitudes, considerando estrutura do modelo em relação à presença ou não de constante e/ou tendência, e quantidade de defasagens como fatores. Modelos autorregressivos do tipo AR(1) foram considerados para a geração de dados pelo método de Monte Carlo, que poderiam apresentar diferentes intensidades para o coeficiente associado à primeira defasagem. Depois da aplicação do teste ADF, foram determinadas as proporções de rejeição da hipótese nula em cada condição experimental, sendo utilizada uma análise de variância com a estatística qui-quadrado para verificar a influência da quantidade de defasagens no valor-p. Os resultados mostram que se houver raiz unitária, o teste apresenta bons resultados, independentemente da quantidade de defasagens considerada. Entretanto, o mesmo não foi observado nos casos em que a série temporal não apresenta raiz unitária.

ABSTRACT In this paper we evaluate how much influence the number of selected lags has in the p-value obtained from the statistic considered in an augmented Dickey-Fuller test (ADF). Three experiments with different series sizes were carried out considering the presence (or not) of a constant and/or trend, and also different number of lags. Autoregressive models (AR1) are used in the data generating process through the Monte Carlo method, considering different values for the coefficient associated with the first lag. After the application of the ADF test, we calculate the proportion of times when the null hypothesis was rejected in each scenario, and perform an analysis of variance (considering chi-square statistic) to verify the influence of the number of selected lags in the p-value. Results show that if a unit root is verified, then the test presents a good performance, regardless of the number of lags. However, the same was not observed in cases where the time series does not present a unit root.

Abstract Gold mining and ore processing are activities of great economic importance. However, they are related to generation of extremely polluted effluents containing high concentrations of heavy metals and low pH. This study aims to evaluate the optimal conditions for gold mining effluent treatment by crossflow membrane filtration regarding the following variables: nanofiltration (NF) and reverse osmosis (RO) membrane types, feed pH and permeate recovery rate. It was observed that retention efficiencies of NF90 were similar to those of RO membranes though permeate fluxes obtained were 7-fold higher. The optimum pH value was found to be 5.0, which resulted in higher permeate flux and lower fouling formation. At a recovery rate above 40% there was a significant decrease in permeate quality, so this was chosen as the maximum recovery rate for the proposed system. We conclude that NF is a suitable treatment for gold mining effluent at an estimated cost of US$ 0.83/m3.

Resumo O aproveitamento de resíduos sólidos poluentes produzidos em distintas atividades industriais (resíduo de casca de ovo galináceo e resíduo de escória de soldagem) como fonte de matérias-primas alternativas para produção de tijolos solo-cimento para construção civil foi investigado. Tijolos solo-cimento contendo até 30% em massa de resíduo sólido industrial foram preparados por prensagem uniaxial e curados durante 28 dias. Ênfase especial é dada à influência da adição dos resíduos sólidos sobre as propriedades técnicas (retração volumétrica, absorção de água, densidade aparente, durabilidade e resistência à compressão simples) e microestrutura dos tijolos solo-cimento. A evolução microestrutural foi avaliada via microscopia confocal. Os resultados experimentais mostraram que os resíduos sólidos industriais se comportam como um material de carga, bem como influenciam ambas as propriedades técnicas e microestrutura dos tijolos solo-cimento. Foi estabelecido que até 15% em massa de resíduo de escória de fluxo de soldagem e até 30% em massa de resíduo de casca de ovo galináceo poderiam ser adicionados em tijolos solo-cimento para uso como material de construção.

Abstract The reuse of pollutant solid wastes produced in distinct industrial activities (avian eggshell waste and welding flux slag waste) as a source of alternative raw material for producing soil-cement bricks for civil construction was investigated. Soil-cement bricks containing up to 30 wt% of industrial solid waste were uniaxially pressed and cured for 28 days. Special emphasis is given on the influence of solid waste addition on the technical properties (as such volumetric shrinkage, water absorption, bulk density, durability, and compressive strength), microstructure and mineral phases of soil-cement bricks. Microstructural evolution was evaluated via confocal microscopy. The experimental results showed that the solid wastes behave as charge material and influenced both technical properties and microstructure of the soil-cement bricks. It was found that up to 15 wt% of welding flux slag waste and up to 30 wt% of avian eggshell waste could be added into the soil-cement bricks for use as building material.

Resumo O estudo objetivou verificar a resistência flexural biaxial (RFB) de uma vitrocerâmica reforçada por leucita totalmente sinterizada, após desgaste com brocas diamantadas de diferentes granulações, e analisar a correlação desses valores com a rugosidade gerada na superfície desgastada. Para isso, 104 pastilhas obtidas a partir de blocos cerâmicos para CAD/CAM foram divididas em 4 grupos (n=26) de acordo com as diferentes granulações dos instrumentos de desgaste: extrafina, fina, média e grossa. Os parâmetros de rugosidade Ra e RyMax foram medidos e as amostras foram mantidas a seco por 7 dias. Ensaio de flexão foi realizado conforme a ISO 6872 e a RFB foi calculada. Dados de RFB, Ra e RyMax foram submetidos à análise de variância Kruskal-Wallis e teste LSD para comparação das médias. Análise de Weibull foi realizada para comparação da resistência característica e módulo de Weibull (confiabilidade). Análise de regressão foi feita para RFB vs. Ra e RyMax. A granulação das brocas apresentou efeito negativo sobre a RFB da cerâmica (117 MPa para extrafina e 83 MPa para grossa). A correlação (r) entre rugosidade superficial e RFB foi de 0,78 para RyMax e de 0,73 para Ra. A granulação das brocas tem um efeito significativo na resistência flexural de cerâmicas vítreas totalmente sinterizadas. Logo o corte deve ser realizado com instrumentos de menor granulação possível, a fim de minimizar irregularidades superficiais e otimizar a resistência estrutural.

Abstract The purpose of the present study was to determine the biaxial flexural strength (BFS) of a CAD/CAM leucite reinforced glass-ceramic ground by diamond burs of different grit sizes and the influence of surface roughness on the BFS. For this, 104 plates were obtained from CAD/CAM ceramic blocks and divided into 4 groups (n = 26), according to bur grit size: extra-fine, fine, medium and coarse. Roughness parameters (Ra, RyMax) were measured, and plates were kept dry for 7 days. The flexural test was carried out and BFS was calculated. Ra, RyMax and BFS data were subjected to analysis of variance and post-hoc test. Weibull analysis was used to compare characteristic strength and Weibull modulus. Regression analysis was performed for BFS vs. Ra and RyMax. When burs with coarse grit were used, higher surface roughness values were found, causing a negative effect on the ceramic BFS (117 MPa for extra-fine, and 83 MPa for coarse). Correlation (r) between surface roughness and BFS was 0.78 for RyMax and 0.73 for Ra. Increases in diamond grit size have a significant negative effect on the BFS of leucite-reinforced glass-ceramics, suggesting that grinding of sintered glass-ceramic should be performed using burs with the finest grit possible in order to minimize internal surface flaws and maximize flexural strength.

Abstract This study evaluated the technical and economic feasibility of membrane bioreactors (MBR) followed by nanofiltration (NF) for dairy wastewater treatment in order to reuse the treated effluent. It was observed that the MBR efficiently removed the organic matter and color of the feed effluent; however, due to the high concentration of dissolved solids in the permeate, it was necessary to use nanofiltration as a polishing step. The final treated effluent could be reused in the industry for cooling, steam generation and cleaning of external areas. A preliminary economic analysis showed the feasibility of the proposed system. The internal rate of return was greater than or equal to 32% when membrane lifespan was at least 2 years and the depreciation time was 15 years. The total cost of the proposed treatment system ranged from R$ 9.99/m3 to R$ 6.82/m3, depending on membrane lifespan.

Among the food industries, the dairy industry is considered to be the most polluting one because of the large volume of wastewater generated and its high organic load. In this study, an aerobic membrane bioreactor (MBR) was used for the treatment of wastewater from a large dairy industry and two hydraulic retention times (HRT), 6 and 8 hours, were evaluated. For both HRTs removal efficiencies of organic matter of 99% were obtained. Despite high permeate flux (27.5 L/h.m²), the system operated fairly stablely. The molecular weight distribution of feed, permeate and mixed liquor showed that only the low molecular weight fraction is efficiently degraded by biomass and that the membrane has an essential role in producing a permeate of excellent quality.

OBJETIVO:Determinar a incidência dos eventos adversos atribuíveis à exsanguíneotransfusão ocorridos em uma Unidade de Terapia Intensiva Neonatal (UTIN) e sua associação com a gravidade clínica do paciente. MÉTODOS: Foram incluídos no estudo todos os recém-nascidos internados com diagnóstico de doença hemolítica perinatal por aloimunização Rh em uma unidade neonatal no período de dez anos. Os pacientes foram separados em dois grupos de acordo com o quadro clínico anterior à exsanguíneotransfusão e calculou-se o risco relativo para cada evento adverso entre os grupos. RESULTADOS: 300 recém-nascidos foram internados com diagnóstico de anemia hemolítica por aloimunização Rh durante o período do estudo. Desses, 143 foram submetidos a 207 exsanguíneotransfusões, sendo que 93 (65%) realizaram apenas um procedimento. A principal indicação da exsanguíneotransfusão foi a velocidade de hemólise (57%). A incidência de eventos adversos foi 22,7% e a mortalidade associada ao procedimento ocorreu em 0,7% dos pacientes. Os eventos adversos, em sua maioria, foram assintomáticos e o mais comum foi a plaquetopenia. Os pacientes do Grupo 2, que apresentarem icterícia associada a outros agravos clínicos antes do procedimento, tiveram um risco 2,1 vezes maior de apresentar eventos adversos graves (RR: 2,1; IC 95%: 1,3-3,4). Houve apenas um óbito relacionado ao procedimento no período. CONCLUSÕES: Apesar de a exsanguíneotransfusão ser um procedimento frequentemente utilizado em casos de hiperbilirrubinemia grave, é alta a incidência de eventos adversos a ela relacionada, principalmente se a condição clínica do paciente for instável antes do procedimento.

OBJECTIVE:To determine the incidence of adverse events associated with exchange-transfusions performed during the past ten years and to evaluate if there is association between the severity of patient's clinical condition before the procedure and the incidence of adverse events. METHODS: All infants admitted to treat hemolytic disease secondary to Rhesus Alloimunoization in the Neonatal Intensive Care Unit were enrolled in the study. Patients were divided into two groups: Group 1, neonates admitted solely for asymptomatic hyperbilirubinemia before the exchange transfusion; Group 2, neonates with other medical conditions besides the hemolytic jaundice. Incidence of adverse events was determined, as well as the relative risk of each adverse event. RESULTS: 300 newborn infants with Rh hemolytic jaundice were studied. A total of 143 patients underwent 207 exchange transfusions. The rate of increase in the serum bilirubin levels (>0,5mg/dL/hour) was the main indication for exchange transfusion. Adverse events occurred in 22.7% of the cases and the mortality rate was 0.7%. The majority of adverse events were asymptomatic, and low platelet count was the most frequent one. The incidence of serious adverse events (bradycardia or heart arrhythmias and thrombocytopenia) was 2.1 times higher in Group 2 than in Group 1 (RR: 2.1; CI: 95% 1.3-3.4). There was one death during the study period associated to the procedure. CONCLUSIONS: Although exchange transfusion is a frequent procedure for treating severe neonatal hyperbilirubinemia, the incidence of adverse events is high, especially if patients' clinical condition is unstable before the procedure.

O índice de condição (IC) de ostras é um índice ecofisiológico utilizado para avaliar a qualidade e a produtividade em cultivos de bivalves. No presente estudo, o IC de ostras de uma baía contaminada por metais pesados foi analisado em relação ao conteúdo de Zn e Cd nos tecidos moles, à liberação de gametas após o período reprodutivo e à infestação por poliquetas. O IC foi calculado com uma nova técnica que utiliza moldes da cavidade interna da concha para medir seu volume. Os maiores valores de IC (acima de 9 na estação seca) podem estar relacionados à disponibilidade de material particulado em suspensão rico em matéria orgânica na baía, enquanto a rápida redução do IC observada de uma temporada a outra em algumas estações é um provável efeito da liberação de gametas. A infestação por poliquetas foi considerada baixa (18,7%) e não apresenta efeitos claros no IC. Apenas Cd nos tecidos de ostras coletadas durante a estação das chuvas apresentou correlação baixa, porém significativa (r = -0,36; p < 0,05), com o IC. Todas as outras correlações entre metais e IC foram estatisticamente não significativas. As variações do IC observadas em escala espacial e temporal parecem ser causadas mais pela disponibilidade de material particulado rico em material orgânico e pela liberação de gametas do que pela infestação por poliquetas e acúmulo de metais nos tecidos.

The condition index (CI) of oysters represents an ecophysiological approach to estimate meat quality and yield in cultured bivalve mollusks. In the present study, the CI of oysters from a heavy-metal polluted bay was analyzed with respect to Zn and Cd contamination in soft tissues, spawning, and polychaete infestation. The CI was calculated through a new technique based on molds made to measure the volume of oyster-shell internal cavities. The higher CI values (over 9 in the dry season) were probably related availability of suspended particles rich in organic matter in the bay, while the rapid reduction in the CI from one season to the next at some stations suggests the effect of spawning. Polychaete infestation was considered low (18.7%) and produced no clear CI effects. The Cd in the oyster tissue collected during the rainy season was weak, although still significantly correlated with the CI (r = -0.36; p < 0.05). All other comparisons of CI and metal concentrations demonstrated a non-significant correlation. The CI variations observed on the temporal and spatial scale were likely to have been caused by availability of organic matter and spawning, rather than spionid infestation or metal body burdens.

The von Willebrand factor cleaving protease (VWFCP) modulates the von Willebrand factor (VWF) multimeric size in normal plasma. VWFCP activity levels are decreased in different physiological and pathologic situations. Different techniques have been developed to unfold the purified VWF (perfusion at high shear rate, dialysis against urea in nitrocellulose filters), to detect the VWFCP activity on it (multimeric analysis of VWF, collagen binding to VWF assay) and to use the patient plasma both as the source of the enzyme and substrate. In this paper we compared the above mentioned methods with new ones: normal plasma dialyzed on membranes instead of purified VWF, dialysis of the samples against urea in tubing instead of nitrocellulose filters, and sonicated plasma to remove the endogenous VWF. The perfusion assay and detection by multimeric analysis showed a limit of detection (25%) of VWFCP activity. Dialysis against urea in both supports and detection by multimeric analysis, showed a better limit of detection (3%), but the recovery of the samples was not as efficient in nitrocellulose filters as it was in tubing. The detection by collagen binding to VWF has more advantages because it allows to analyze more samples than the multimeric analysis does in the same assay. The dialysis of plasma by membranes to obtain the source of exogenous VWF requires no complex equipment. The method, which uses patient plasma as the source of the enzyme and substrate, was inapplicable in our experience because the values could not be interpolated in the reference curve.

La proteasa que cliva al factor von Willebrand (VWFCP) controla el tamaño multimérico del factor von Willebrand (VWF) en plasma normal. Sus niveles se encuentran disminuidos en diferentes situaciones fisiológicas y patológicas. Diferentes técnicas se desarrollaron para desplegar al VWF purificado (perfusión a alta fuerza de cizallamiento, diálisis contra urea en filtros de nitrocelulosa), para detectar la actividad de la VWFCP (análisis multimérico del VWF, enlace del VWF al colágeno) y para usar el plasma del paciente como fuente de enzima (VWFCP) y de sustrato (VWF). Este trabajo compara los métodos descritos con métodos nuevos: plasma dializado en membranas en lugar de VWF purificado, diálisis de la muestra contra urea en tubos, en lugar de filtros de nitrocelulosa y plasma sonicado para remover el VWF endógeno. El ensayo de perfusión y la detección por análisis mutimérico mostró un límite de detección de la actividad de la VWFCP del 25%. La diálisis contra urea en ambos soportes y la detección por análisis multimérico arrojó un límite mejor (3%), pero la recuperación de las muestras no fue tan eficiente en filtros de nitrocelulosa como en tubos. La detección por enlace del VWF al colágeno posee mayores ventajas al analizar más muestras en el mismo ensayo. La diálisis de plasma en membranas, para obtener VWF exógeno, no requiere equipos complejos. El método que usa el plasma del paciente como fuente de enzima y sustrato fue inaplicable en nuestras manos ya que los valores no pudieron ser interpolados en la curva de referencia.

In this study, the micronuclei test (MNT) was applied in exfoliated cells of buccal mucosa, in order to evaluate the genotoxic risk associated with occupational exposure of mechanics, storage battery renovation workers, and car painters. For each individual, 3000 exfoliated buccal cells were analyzed. There was a significantly higher frequency of micronucleated cells (MNC) in the exposed workers than in controls. Smoking and drinking habits, age, and working time did not represent significant factors in terms of increasing the production of micronuclei (MN), when the control and the exposed groups were compared. These results allowed to conclude that the studied individuals belong to a risk group and should periodically undergo biological monitoring and proper care.

Some biological effects of feeding larvae of the armyworm Spodoptera latifascia with leaves of three plant species (cotton, soybean and lettuce) have been studied. Some indicative measurements were utilized to determine the host suitability of these three plant species. Cotton leaves (Gossypium hirsutum) were found to be better than soybean (Glycine max) for the development and growth of this insect. Lettuce leaves (Lactuca sativa) were incapable of sustaining this insect. Moreover, the stress of the latter diet was associated with a latent microbial disease, a mixed infection caused by Vairimorpha sp. and a nuclear polyhedrosis virus (NPV). Cotton leaves can be recommended as a suitable diet for mass rearing of this insect species. Due to recent outbreks of S. latifascia observed in the States of São Paulo, Santa Catarina and Paraná and because of the frequent applications of wide spectrum chemical insecticides, it can be expected that this insect will soon become one of the important pests threatening cotton and other economic plantations in Brazil.