663 research outputs found

    Accumulation of heavy metals in sediments of the Parnaíba river delta

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    This study was carried out to assess the impacts of heavy metals coming into the Parnaíba River Delta in the Brazilian Northeastern region. The sediment concentrations of different heavy metals, such as Pb, Ni, Cr, Cd, Zn, Cu, Fe, Al and Mn, were measured by flame spectrometry. The sediments were collected from 19 sites distributed along 5 estuarine channels. The average concentrations found for Cu and Zn are compatible with the TEL (Threshold Effect Level). However, Cd concentrations were above the PEL (Probable Effect Level) values, while Ni and Cr showed intermediate mean concentrations. There are no established concentration limits for Mn, Al and Fe. These are the first metal biogeochemistry findings in the area and will contribute to the decision-making of environmental authorities, aiming to control the emissions of metallic pollutants in this important area of the Brazilian coast.Centro de Investigaciones Geológica

    Accumulation of heavy metals in sediments of the Parnaíba river delta

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    This study was carried out to assess the impacts of heavy metals coming into the Parnaíba River Delta in the Brazilian Northeastern region. The sediment concentrations of different heavy metals, such as Pb, Ni, Cr, Cd, Zn, Cu, Fe, Al and Mn, were measured by flame spectrometry. The sediments were collected from 19 sites distributed along 5 estuarine channels. The average concentrations found for Cu and Zn are compatible with the TEL (Threshold Effect Level). However, Cd concentrations were above the PEL (Probable Effect Level) values, while Ni and Cr showed intermediate mean concentrations. There are no established concentration limits for Mn, Al and Fe. These are the first metal biogeochemistry findings in the area and will contribute to the decision-making of environmental authorities, aiming to control the emissions of metallic pollutants in this important area of the Brazilian coast.Centro de Investigaciones Geológica

    Accumulation of heavy metals in sediments of the Parnaíba river delta

    Get PDF
    This study was carried out to assess the impacts of heavy metals coming into the Parnaíba River Delta in the Brazilian Northeastern region. The sediment concentrations of different heavy metals, such as Pb, Ni, Cr, Cd, Zn, Cu, Fe, Al and Mn, were measured by flame spectrometry. The sediments were collected from 19 sites distributed along 5 estuarine channels. The average concentrations found for Cu and Zn are compatible with the TEL (Threshold Effect Level). However, Cd concentrations were above the PEL (Probable Effect Level) values, while Ni and Cr showed intermediate mean concentrations. There are no established concentration limits for Mn, Al and Fe. These are the first metal biogeochemistry findings in the area and will contribute to the decision-making of environmental authorities, aiming to control the emissions of metallic pollutants in this important area of the Brazilian coast.Centro de Investigaciones Geológica

    Perfil de FSH e LH na divergência folicular em novilhas Nelore (Bos indicus)

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    Present study aimed to evaluate gonadotropins profiles in 12 Nelore heifers, in order to test the hypothesis that FSH concentrations decrease and LH presents a transient increase during follicle selection. Blood samples from jugular vein were harvested twice daily starting at the time of ovulation (D0) until D5. Plasma samples were assayed for FSH and LH by double antibody radioimmunoassay method. LH and FSH assay sensitivity was 0,02ng/ml and 0,005ng/ml, respectively. The intraassay coefficient of variation was 13,6% and 18,8%, respectively. Data (mean±SEM) were normalized to follicle deviation and analyzed by ANOVA and by linear, cubic, and quadratic regressions. Comparisons between higher and lower FSH values were also performed by T-test. There was no effect of time in plasmatic FSH and LH circulating levels when variance analysis or regression analysis were performed. However, by T-test, FSH concentrations reached the lowest plasmatic levels 36 (0,40±0,05ng/ml) and 60 hours (0,42±0,04ng/ml) after follicular deviation, comparatively to 36 hours before deviation, when the concentrations were maximal (0,63±0,08ng/ml). In conclusion, there is a FSH decrease, although a transient LH elevation has not been confirmed encompassing follicle deviation in Nelore females.O presente estudo teve como objetivo traçar o perfil de gonadotrofinas em 12 novilhas Nelore, a fim de testar a hipótese de que há declínio nas concentrações de FSH e elevação transitória nos níveis de LH durante a seleção folicular. A partir da ovulação (D0) foram colhidas amostras de sangue da veia jugular a cada 12 horas até o D5, para a dosagem de FSH e LH plasmáticos. Empregou-se o método de radioimunoensaio de duplo anticorpo. A sensibilidade do ensaio de LH foi de 0,02ng/ml e a de FSH de 0,005ng/ml. Os coeficientes de variação intra-ensaio foram 13,6% e 18,8%, respectivamente. Os dados (média±EPM) foram normalizados para o momento da divergência folicular e, posteriormente, analisados por ANOVA e por regressão linear, cúbica e quadrática. Também foi empregado o Teste t para comparação entre o ponto mais alto e o mais baixo da curva. Não se verificou efeito de tempo sobre as concentrações plasmáticas de FSH e de LH quando se utilizou análise de variância e de regressão. Entretanto, através do Teste t pontual, o FSH atingiu as menores concentrações plasmáticas 36 (0,40±0,05ng/ml) e 60 horas (0,42±0,04ng/ml) após a divergência, comparativamente às 36 horas anteriores ao desvio, quando as concentrações foram máximas (0,63±0,08ng/ml). Conclui-se, portanto, que há declínio nas concentrações plasmáticas de FSH, contudo, não foi comprovada elevação transitória nas concentrações de LH próximo ao momento do desvio folicular em fêmeas Nelore

    In vitro evaluation of the antimicrobial activity of five root canal sealers

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    The aim of the present study was to analyze the antimicrobial properties of five endodontic sealers: Endo Fill, Endomethasone, Endomethasone N, Sealer 26 and AH-Plus, against the following microorganisms: Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus sanguis and Actinomyces naeslundii. The sealers were tested immediately, 24 h, 48 h and 7 days after manipulation.The direct contact method through the observation of the microbial growth in liquid medium and the agar diffusion test were used to evaluate the antimicrobial properties of the sealers. The results, in both methodologies used, showed that immediately after manipulation, Endo-Fill and Endomethasone demonstrated the highest antimicrobial activity, with no statistically significant difference between them. Sealer 26 demonstrated the lowest antimicrobial activity. At all other times after manipulation, there were no statistically significant differences among all the sealers tested. In conclusion, none of the sealers totally inhibited the growth of the microorganisms. Furthermore, the antimicrobial activity of each sealer decreased with time and was dependent upon the microbial susceptibility to them.O objetivo do presente estudo foi analisar as propriedades antimicrobianas de cinco cimentos endodônticos: Endo Fill, Endomethasone, Endomethasone N, Sealer 26 e AH-Plus, em diferentes períodos pós-manipulação, i.e., imediatamente e após 24 horas, 48 horas e 7 dias, contra os seguintes microrganismos: Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus sanguis e Actinomyces naeslundii. Os métodos usados foram o contato direto através da observação do crescimento microbiano em meio líquido e o teste de difusão em agar. Os resultados, nas duas metodologias usadas, mostraram que: 1) imediatamente após a manipulação, Endo-Fill e Endomethasone apresentaram a maior atividade antimicrobiana, sem diferenças estatisticamente significantes entre eles. Sealer 26 teve a menor atividade antimicrobiana; 2) nos outros tempos pós-manipulação, não houveram diferenças estatisticamente significantes entre os cimentos testados. Foi concluído que nenhum dos cimentos inibiu completamente o crescimento dos microrganismos testados. A atividade antimicrobiana de cada cimento diminuiu com o tempo e dependeu da suscetibilidade microbiana a eles.3035Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Motivação e atitudes de professores da rede pública de municípios cearenses diante do ensino de surdos

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    The person learning disabled constitutes a challenge for teachers, considering the training, qualification, directed institutional policies and human and material resources available. However, these variables alone will not justify certain difficulties presented by these professionals when faced with this demand. Considering the influence of these factors and the importance of motivation and positive attitudes of teachers in front of the deaf students education, proceeded to study of 200 public school teachers of six Ceara’s municipalities to identify the motivation and attitude before teaching of deaf students. It conducted content analysis from the issues raised in open questions, and the data evaluated in IRAMUTEQ software through lexical analysis with cloud forming words. From these six categories were constructed and discussed in light of literature. It was identified little motivation, however, permeated by positive attitudes, that although focus the issue of capacity building as a key factor for performance, reflecting the attitude of a teacher who supports the inclusion and seeks new strategies to create opportunities to insert this student.A educação de alunos com necessidades especiais se constitui grande desafio para os professores, considerando a formação, qualificação, políticas institucionais direcionadas e recursos humanos e materiais disponíveis. Porém, essas variáveis por si, não justificam certas dificuldades apresentadas por estes profissionais ao se depararem com esta demanda. Considerando a influência destes fatores e a importância da motivação e de atitudes positivas de professores diante da educação de alunos surdos, procedeu-se estudo com 200 professores da rede pública de seis municípios cearenses a fim de identificar a motivação e atitude dos mesmos diante do ensino de alunos surdos. Realizou-se análise de conteúdo a partir dos temas levantados em questões abertas, sendo os dados avaliados no software IRAMUTEQ por meio de análise lexicográfica com formação de nuvem de palavras. A partir destas, seis categorias foram construídas e discutidas à luz da literatura pertinente. Identificou-se pouca motivação, porém, permeadas por atitudes positivas, que, embora enfoquem a questão da capacitação como fator primordial para atuação, refletem a postura de um professor que apoia a inclusão e busca novas estratégias para oportunizar a inserção deste aluno

    Spectroscopic analysis of sediments from a tropical estuary in the Brazilian Northeast

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    The purpose of this work is to characterize the geochemical composition of sediments of the Parnaíba River delta, in terms of trace metal concentrations, using spectroscopic techniques. A profile sampling campaign was carried out in April 2017. The granulometric analysis of the surface sediments showed that the silt + clay fraction added up to 14.31% of the total. The mean concentrations of heavy metals in the profiles were 1.78 mg.kg-1 for Cd; 10.57 mg.kg-1 for Cr; 11.85 mg.kg-1 for Cu; 24.42 mg.kg-1 for Ni; 47.90 mg.kg-1 for Zn; 152.45 mg.kg-1 for Pb; 1887.28 mg.kg-1 for Mn; 1.12% for Al and 3.49% for Fe. Scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) applied to the sediments from the coast of Ceará showed the morphological diversity of sediment grains. The infrared spectra presented similar functional groups at all tested points, demonstrating that the clay minerals in the different samples probably have the same origin.Centro de Investigaciones Geológica

    Spectroscopic analysis of sediments from a tropical estuary in the Brazilian Northeast

    Get PDF
    The purpose of this work is to characterize the geochemical composition of sediments of the Parnaíba River delta, in terms of trace metal concentrations, using spectroscopic techniques. A profile sampling campaign was carried out in April 2017. The granulometric analysis of the surface sediments showed that the silt + clay fraction added up to 14.31% of the total. The mean concentrations of heavy metals in the profiles were 1.78 mg.kg-1 for Cd; 10.57 mg.kg-1 for Cr; 11.85 mg.kg-1 for Cu; 24.42 mg.kg-1 for Ni; 47.90 mg.kg-1 for Zn; 152.45 mg.kg-1 for Pb; 1887.28 mg.kg-1 for Mn; 1.12% for Al and 3.49% for Fe. Scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) applied to the sediments from the coast of Ceará showed the morphological diversity of sediment grains. The infrared spectra presented similar functional groups at all tested points, demonstrating that the clay minerals in the different samples probably have the same origin.Centro de Investigaciones Geológica
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