In the present work, the sol-gel synthesis method was employed as strategy to obtain a magnetic and mesoporous silica-niobia material. The planned synthesis was based on the hetero-condensation of niobium and silicon alkoxide precursors, in the presence of spherical magnetite particles. The resulting material presented interesting characteristics such as magnetism, large mesopores, in the range from 20 to 50 nm, and 68 m2 g-1 of surface area. These features allowed its use as modifier of carbon paste electrode for p-nitrophenol determination, since niobia has never been used in electrochemical sensors for the determination of nitrophenol compounds. By using differential pulse voltammetry technique, the electrode can be applied in a wide range of p-nitrophenol concentration, from 10 to 490 μmol L-1, with a limit of detection of 1.2 µmol L-1 and sensitivity up to 0.60 µA L µmol-1. The proposed electrode presented good sensitivity and selectivity and it was applied in real water samples.

Ultrasound as a metrology tool has many applications in health care, industrial, and chemical analyses. Ultrasonic techniques are rapid, low-cost, non-invasive, and highly repeatable. Although ultrasound can be used to measure emulsions, no effort had been made thus far to optimize its sensitivity for metrological analysis. In this work, a technique for analyzing oil in water was validated. The wave velocity and attenuation were chosen as the ultrasonic parameters. The technique was implemented in the boundary region established by law for effluents from industrial plants involved with biofuel manufacturing. A technical effort of this study was to establish stable emulsions in concentrations close to the desired limit of study. The phase behaviours of pseudo-ternary oil, sodium chloride, and sodium lauryl sulphate were studied. The composition in the widest region of the diagram allowed for the formation of a stable emulsion, from which the ultrasound measurement was carried out. An analytical curve was obtained using ultrasonic attenuation to determine the content of oils and greases in wastewater ranging 15–240 ppm. The speed of sound did not appear to be an applicable parameter for this application. The technique was demonstrated to be an important alternative solution for the continuous monitoring of wastewater with regard to oil concentrations.

A escassez de pesquisas específicas sobre a sequência de eventos que determinam o crescimento das plantas, desde o meristema até a formação de madeira, representa uma lacuna no conhecimento sobre a dinâmica de crescimento de espécies lenhosas. Neste trabalho, foi realizado o levantamento dos estudos publicados sobre a atividade cambial de espécies nativas brasileiras com a finalidade de comparar a metodologia aplicada e os resultados obtidos. A sazonalidade anual do câmbio foi observada em todas as espécies investigadas. Todavia, foi observada uma alta heterogeneidade nas metodologias utilizadas. Como resultado desta análise, a nossa opinião aponta para a necessidade de padronizar os protocolos de amostragem e de discutir a adequação do delineamento experimental. Isso permitiria definir, com maior precisão, os fatores que determinam o crescimento radial em diferentes tipos de ecossistemas tropicais.

The lack of specific research on the sequence of events that determine plant growth from meristem until wood formation represents a gap in the knowledge of growth dynamics in woody species. In this work, we surveyed published studies concerning cambial activity of Brazilian native species aiming at allowing the comparison of applied methods and obtained results. The annual cambial seasonality was observed in all the investigated species. Nevertheless, we found high heterogeneity in the used methodologies. As a result from this analysis, our opinion points to the need for standardizing sampling protocols and for discussing the suitability of experimental designs. This will help to define with greater precision the factors that determine the radial growth in the different tropical ecosystems.

O presente estudo teve como objetivo determinar a presença de hemogregarina em boídeos mantidos em cativeiro no Estado do Pará, bem como, relacionar a hemoparasitose com pre-disposição sexual, alterações clínicas e hematológicas e a presença de ectoparasitos. Esta pesquisa teve autorização do Sistema de Autorização e Informação em Biodiversidade do Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis para ser realizado. Utilizaram-se 19 serpentes da família Boidae mantidas em cativeiro, pertencentes ao "Museu Paraense Emilio Goeldi" (Belém/PA) e "Sítio Xerimbabo" (Santo Antônio do Tauá/PA). A pesquisa de hemogregarina foi realizada em esfregaços sanguíneos examinados no aumento de 400x, enquanto que a parasitemia foi determinada contando- se 550 hemácias em aumento de 1000x. Do total de animais estudados (n=19), nove encontraram-se parasitados (47,36%), não havendo correlação entre presença de hemogregarina, pré-disposição sexual, alterações clínicas e hematológicas nas serpentes hospedeiras. A correlação da hemoparasitose foi detectada apenas quanto à presença de ectoparasitas nas serpentes, no entanto, estudos adicionais são necessários para verificar a prevalência de hemogregarinas em animais mantidos em cativeiro no Estado do Pará, visto que, existe grande lacuna de dados na literatura veterinária especializada no que diz respeito à fauna da região amazônica.

We aimed to determine hemogregarines presence in snakes of the Boidae family kept in captivity in Pará (PA), Brazil, and to relate it with sex, clinical and hematological and ectoparasitism. This study had authorization from Sisbio/IBAMA to be done. Nineteen Boa constrictor snakes were used, belonging to the "Museu Paraense Emílio Goeldi" (Belém/ PA) and "Xerimbabo Farm" (Santo Antônio do Tauá/PA). Blood smears were examined with 400x magnification, while the parasitemia percentage was determined by counting 550 red blood cells with 1000x magnification. From the snakes studied (n=19), nine were parasitized (47.36%) and there was no correlation between hemogregarines presence, sex, clinical and hematological changes. Hemoparasitosis correlation was detected only with the ectoparasites presence; however further studies are needed to determine the real hemogregarines prevalence in snakes kept in captivity in Pará, since there is a huge gap of data in the veterinary specialized literature about the fauna of the Amazon region.