Abstract In this work, we report the synthesis of YbxZn1-xO nanoparticles (0.000 ≤x≤ 0.100) by polymer precursor method and the study of their vibrational and structural properties. Thermal analysis of the polymeric precursor showed that the thermal decomposition occurs in few stages, with the crystallization of the wurtzite structure taking place at a temperature below 500 C. Fourier transform infrared spectroscopy indicated the presence of Zn-O and Yb-O bonds. X-ray diffraction data showed the formation of the ZnO wurtzite phase for all samples. The application of the Rietveld method revealed a decrease in the average particle size and an increasing trend in unit cell volume as the Yb3+ content increased. Additionally, the nearest-neighbor bond lengths along and off the c-direction, as well as the bond angles, were calculated. The results obtained provided additional evidence on the efficiency of Yb3+ doping by the polymer precursor method.

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.

Carbon quantum dots (C-dots) with average size of 9 nm were synthesized from an aqueous solution of raw cashew gum (RCG) using a novel and fast microwave-assisted technique which involves two steps. In the first step (partial depolymerization in solution) some monomer units are formed through the autohydrolysis of CG and a small amount of 5-hydroxymethyl furfural can be obtained. The second step involves polycondensation/polymerization to give rise to a polyfuranic structure followed by aromatization/carbonization and nuclear burst. At the end of the process a composite of partially depolymerized CG and C-dot was formed. A mechanism involved in microwave-assisted two-steps synthesis was suggested. Although no passivation reagent was used, an intensely blue photoluminescent material in UV light was obtained. C-dot was characterized by spectroscopy in the medium infrared, thermal analysis, gel permeation chromatography, transmission electron microscopy, zeta potential, and photoluminescence.

Introdução: A recorrência da exposição ao abuso sexual na infância (ASI) parece ser maior entre vítimas de abuso sexual. Nesse sentido, experiências relacionadas à violência sexual podem perpetuar-se dentro do próprio contexto familiar por diversas maneiras. Aqui, investigamos a associação entre ser exposto a ASI e ter um filho vítima de abuso sexual.Método: Usamos uma amostra com 123 mães, que foram divididas em 2 grupos: um composto por 41 mães de filhos abusados sexualmente e outro composto por 82 mães de filhos não abusados. O histórico da exposição à ASI foi avaliado por meio do Childhood Trauma Questionnaire - Short Form (CTQ) e usamos um modelo de regressão logística para estimar os valores preditivos em relação a ter ou não um filho exposto a violência sexual.Resultados:Mães de crianças vítimas de abuso sexual obtiveram maiores escores no CTQ, especialmente na subescala de abuso sexual (SA). Segundo nosso modelo de regressão logística, escores maiores no CTQ foram capazes de predizer significativamente a categoria de ser ou não mãe de uma criança vítima de violência sexual em nossa amostra (Wald = 7,074; p = 0,008; Exp(B) = 1,681). O número de anos de escolaridade reduziu a chance de ter um filho vítima de violência sexual (Wald = 18,994; p = 0,001; Exp(B) = 0,497).Conclusão: Nossos achados ressaltam a importância de um possível efeito intergeracional do abuso sexual. Intervenções familiares e preventivas contra maus-tratos na infância deveriam levar em consideração essa problemática.

Introduction: Recurrent exposure to childhood sexual abuse (CSA) seems to be higher among victims of sexual abuse. In this sense, experiences related to sexual violence can perpetuate within the family context itself in various ways. Here, we investigate the association between being exposed to CSA and having a child victim of sexual abuse.Method: We used a sample with 123 mothers, who were divided into 2 groups: one consisting of 41 mothers of sexually abused children and another consisting of 82 mothers of non-sexually abused children. History of exposure to CSA was evaluated by means of the Childhood Trauma Questionnaire - Short Form (CTQ) and we used a logistic regression model to estimate the prediction values regarding having or not a child exposed to sexual violence.Results: Mothers of sexually abused children had significantly higher scores on CTQ, especially on the sexual abuse subscale (SA). According to our logistic regression model, higher scores on the CTQ significantly predicted the status of being a mother of children exposed to sexual violence in our sample (Wald = 7.074; p = 0.008; Exp(B) = 1.681). Years of formal education reduced the likelihood of having a child victim of sexual violence (Wald = 18.994; p = 0.001; Exp(B) = 0.497).Conclusion: Our findings highlight the importance of a possible intergenerational effect of sexual abuse. Family intervention and prevention against childhood maltreatment should take this issue in account.

Vinte e dois genótipos de pimentão (Capsicum annuum L.) foram cultivados em vasos com 2,45 dm3 de solo em seis doses de fósforo (P) (25, 50, 100, 200, 300 e 600 mg.dm-3 P). Avaliou-se o desempenho dos genótipos em cada dose de P aplicada pelas características que expressam o crescimento e a eficiência nutricional. Houve acentuada diferença entre os genótipos nas várias doses de P, tanto na acumulação de matéria seca total quanto nas demais características relacionadas com o crescimento, enquanto, para as características nutricionais, houve menores diferenças. Entre as diferentes doses, a de 200 mg.dm-3 P, pela maior precisão experimental e maior variabilidade genotípica, foi escolhida como a mais indicada para a identificação de genótipos tolerantes à baixa disponibilidade de P e para estudos genéticos. Pela comparação das médias de matéria seca total e com base em funções discriminantes (técnica de análise multivariada proposta por T.W. Anderson), identificaram-se seis genótipos tolerantes, dez moderadamente tolerantes e seis intolerantes ao baixo teor de P. Aparentemente, um único fator foi o responsável pela diferença no crescimento entre os genótipos tolerantes e intolerantes. Os tolerantes, que foram 2,34 vezes mais eficientes na produção de matéria seca total, acumularam 2,38 vezes mais P, em média, do que os intolerantes, provavelmente em razão da sua maior biomassa de raiz. Diferenças no uso interno do P não contribuíram para a diferenciação dos genótipos tolerantes e intolerantes.

Twenty two genotypes of sweet pepper (Capsicum annuum L.) were grown in pots containing 2.45 dm3 soil, in which six phosphorus (P) levels were applied (25, 50, 100, 200, 300 and 600 mg.dm-3 P). For each P level, the genotype performance was evaluated according to the characteristics expressing growth and nutritional efficiency. For several P levels, there was an occurrence of great differences among genotypes either in total dry matter accumulation and other characteristics related to growth, whereas low differences were observed in the nutritional characteristics. Among all P levels applied, 200 mg.dm-3 P was the most adequate for both identification of genotypes which are tolerant to low P availability and genetic studies, for its experimental accuracy and greater genotypic variability provided. By comparing the averages of total dry matter and based on discriminatory functions (multivariate analysis technique proposed by T. W. Anderson), six genotypes were identified as tolerant, ten as moderately tolerant and six as intolerant to low P contents. Apparently, only one factor was responsible for the difference in growing, which was observed between tolerant and intolerant genotypes. The tolerant genotypes which showed to be 2.34 times more efficient in producing total dry matter, also accumulated 2.38 times more P in the average, than those intolerant, probably due to greater biomass of tolerant-genotype roots. Differences in internal P use did not contribute for the differences between tolerant and intolerant genotypes.