260 research outputs found

    Cyanobacteria, microcystins and cylindrospermopsin in public drinking supply reservoirs of Brazil

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    Brazil has a history of blooms and contamination of freshwater systems by cyanobacterial toxins. The monitoring relevance of toxins from cyanobacteria in reservoirs for public supply is notorious given its high toxicity to mammals, included humans beings. The most recurrent toxins in Brazilian water bodies are microcystins (MC). However, the recent record of cylindrospermopsin (CYN) in northeastern Brazil, Pernambuco state, alerts us to the possibility that this could be escalating. This study reports occurrence of MC and CYN, quantified with ELISA, in 10 reservoirs, devoted to public drinking supply in northeastern Brazil. The composition and quantification of the cyanobacteria community associated with these water bodies is also presented. From 23 samples investigated for the presence of MC, and CYN, 22 and 8 out were positive, respectively. Considering the similarity of the cyanobacteria communities found in reservoirs from Pernambuco, including toxin-producing species associated to MC and CYN, we suggest that geographic spreading can be favored by these factors. These issues emphasize the need for increased monitoring of MC and CYN in drinking supply reservoirs in Brazil861297309O Brasil tem um histórico de florações e contaminações por toxinas de cianobactérias nos seus ecossistemas de água doce. A relevância do monitoramento de toxinas de cianobactérias em reservatórios de abastecimento público é notória, devido à sua alta toxicidade para mamíferos, inclusive seres humanos. As cianotoxinas mais recorrentes em corpos de água brasileiros são microcistinas (MC). No entanto, o registro recente de cilindrospermopsina (CYN) no nordeste, estado de Pernambuco, nos alerta para a possibilidade do aumento de novas ocorrências. Este estudo relata a ocorrência de MC e CYN, quantificadas por ELISA, em 10 reservatórios destinados ao abastecimento público do nordeste do Brasil. Também são apresentadas a composição e a quantificação da comunidade de cianobactérias associadas a estes corpos de água. Das 23 amostras investigadas, 22 e 8 foram positivas em relação, respectivamente, a MC e CYN. Considerando a similaridade das comunidades de cianobactérias encontradas nos reservatórios de Pernambuco e a presença de espécies potencialmente produtoras de MC e CYN, nós sugerimos que uma expansão geográfica possa ser favorecida por esses fatores. Estas questões enfatizam a necessidade de aumentar o monitoramento de MC e CYN em reservatórios de abastecimento público no Brasi

    Height-based equations as screening tools for elevated blood pressure in the SAYCARE study

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    This study evaluated the accuracy of four height-based equations: blood pressure to height ratio (BPHR), modified BPHR (MBPHR), new modified BPHR (NMBPHR), and height-based equations (HBE) for screening elevated BP in children and adolescents in the SAYCARE study. We measured height and BP of 829 children and adolescents from seven South American cities. Receiving operating curves were used to assess formula performance to diagnose elevated BP in comparison to the 2017 clinical guideline. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated for the four screening formulas. The diagnostic agreement was evaluated with the kappa coefficient. The HBE equation showed the maximum sensitivity (100%) in children, both for boys and girls, and showed the best performance results, with a very high NPV (>99%) and high PPV (>60%) except for female children (53.8%). In adolescents, the highest sensitivity (100%) was achieved with the NMBPHR for both sexes. Kappa coefficients indicated that HBE had the highest agreement with the gold standard diagnostic method (between 0.70 and 0.75), except for female children (0.57). Simplified methods are friendlier than the percentile gold standard tables. The HBE equation showed better performance than the other formulas in this Latin American pediatric population

    Microtiming patterns and interactions with musical properties in Samba music

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    In this study, we focus on the interaction between microtiming patterns and several musical properties: intensity, meter and spectral characteristics. The data-set of 106 musical audio excerpts is processed by means of an auditory model and then divided into several spectral regions and metric levels. The resulting segments are described in terms of their musical properties, over which patterns of peak positions and their intensities are sought. A clustering algorithm is used to systematize the process of pattern detection. The results confirm previously reported anticipations of the third and fourth semiquavers in a beat. We also argue that these patterns of microtiming deviations interact with different profiles of intensities that change according to the metrical structure and spectral characteristics. In particular, we suggest two new findings: (i) a small delay of microtiming positions at the lower end of the spectrum on the first semiquaver of each beat and (ii) systematic forms of accelerando and ritardando at a microtiming level covering two-beat and four-beat phrases. The results demonstrate the importance of multidimensional interactions with timing aspects of music. However, more research is needed in order to find proper representations for rhythm and microtiming aspects in such contexts
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