672 research outputs found

    Aquatic contamination of the Turvo Limpo river basin at the Minas Gerais state, Brazil

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    The aquatic contamination from the discharge of untreated or inadequately treated municipal sewage, as well as from husbandry, agriculture, and the disposal of municipal garbage, metallic scraps and civil architecture residues in the neighborhood of the Turvo Limpo River basin was evaluated. The water-courses examined were the São Bartolomeu Stream, Turvo Sujo River, and Turvo Limpo River, located in the Minas Gerais State, Brazil. Water samples were collected at the river-side in the dry season (July, August, and September 2005) and analyzed for evaluation of pollutant inputs. The pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), total phosphate, total ammonia nitrogen (NH3 + NH4+), nitrate and metal concentrations (Al, Ca, Cr, Cu, Fe, Mg, Ni, Pb, and Zn) in water samples were determined. The concentrations of these metals in the suspended solids were also determined. The suspended solids showed high concentrations of Zn (15,350 mg kg-1) and Pb (3,590 mg kg-1), while the stream water was enhanced with Al (1,480 µg L-1). The pH and the concentrations of BOD, total phosphate and total ammonia nitrogen in the water-courses were far from those established by the Brazilian Environmental Standards for Class 2 water. In all examined sites there was an increase in the nitrate concentration compared with that of a spring (site 1). The nitrate concentrations were below those of the total ammonia nitrogen, indicating that the nitrogen in the water-courses was mainly originated from recent sewage discharges, since did not occurred larger mineralization with the formation of nitrate ions

    Reação do mercado à alavancagem operacional: um estudo empírico no Brasil

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    Studies evaluating the impact of financial reporting information on capital market variables have gained great importance in the accounting literature and became a tool for assessing the usefulness of accounting information. The present study follows the l path of earnings-return research, measuring operating leverage as a substitute for net income shown in the financial statements. It is based on data between the second quarter of 2001 and the third quarter of 2004 referring to firms listed on Bovespa (São Paulo Stock Exchange) and relating to the following sectors: petroleum and gas, basic materials, industrial goods, construction and transportation, non-cyclical consumption, and cyclical consumption. The hypothesis of the study is that since operating leverage, besides being related to earnings (operating earnings), is one of the factors determining the systematic risk of stocks, and since there is a relationship between risk and stock returns, it is possible to infer a positive relationship between the degree of operating leverage and stock returns. Empirical tests carried out using panel data methods suggest that the operating leverage is statistically relevant in explaining the behavior of stock returns and that this relationship is positive, as predicted by theory. The results also demonstrate that statistical relevance increases when stricter parameters are employed for analyzing the data and that the conclusions are not determined by outlier behavior. Unit root tests on the data series as well as autocorrelation and heteroskedasticity tests on the residuals ensure the robustness of the results obtained.Estudos que avaliam o impacto de informações contábeis nas variáveis do mercado de ações têm adquirido grande relevância na literatura contábil e se constituído em instrumento de avaliação da utilidade da informação contábil. O presente estudo segue a mesma lógica das pesquisas lucro-retorno, substituindo a medida de resultados contábeis pela de alavancagem operacional e tendo por base os dados das companhias listadas na Bovespa, dos setores de petróleo e gás, materiais básicos, bens industriais, construção e transporte, consumo não cíclico e consumo cíclico, referentes ao período entre o segundo trimestre de 2001 e o terceiro trimestre de 2004. A premissa considerada é a de que, como a alavancagem operacional, além de incorporar uma dimensão de resultado (o lucro operacional), é uma das determinantes do risco sistemático das ações, e de que há relação entre risco e retorno das ações, é possível inferir uma associação positiva entre o grau de alavancagem operacional e o retorno das ações. Os testes empíricos realizados com a utilização do método de dados em painel apresentam evidências de que a variável alavancagem operacional é estatisticamente relevante para explicar o comportamento do retorno das ações e que essa relação é positiva, conforme previsto teoricamente. Os resultados, também, demonstram que a relevância estatística aumenta quando são adotados parâmetros mais rigorosos para a consideração dos dados e as conclusões não são determinadas pelo comportamento dos valores extremos (outliers). Os testes de raízes unitárias nas séries e de autocorrelação e heteroscedasticidade nos resíduos reforçam a robustez dos resultados apurados

    The Effect of Sward Surface Height on Sheep Grazing Activities

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    The objective of this study was to assess the effect of Italian ryegrass (Lolium multiflorum Lam.) sward height on grazing activities. The experiment was carried out at the Research Station of Universidade Federal do Rio Grande do Sul, Brazil. Yearling no-castrated male lambs behavior was assessed in terms of diurnal grazing, ruminating and idling time in three periods: 27 September 11 and 25 October. Sward surface height was monitored using a sward stick and samples of 0.25 m2 were cut to ground level to estimate herbage and leaf lamina mass. The experiment was carried out in a randomised block design with three replications of four treatments: sward surface heights (5, 10, 15 and 20 cm). Grazing time and ruminating time were somewhat interchangeable, decreasing grazing time and increasing ruminating time with increasing sward surface heights. Idling time remained relatively constant. Sward height showed a small effect on biting rate

    Impact Assessment of Urethral Meatus Morphology and Penile Biometry in Transurethral Prostate and Bladder Surgery

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    Objective. To analyze the penile and urethral meatus biometry and its correlation with meatoplasty during endoscopic resections. We also propose a new classification for urethral meatus morphology. Materials and Methods. We prospectively studied 105 patients who underwent prostate and bladder transurethral resections. We performed standardized measurement of penile and urethral meatus biometry followed by penile photo in the front position. The need to perform meatoplasty or dilatation during resectoscope introduction was registered. Data were analyzed comparing the correlation between two groups: without intervention (Group A) and with intervention (Group B). Results. We observed in Group A and Group B, respectively, the average length of urethral meatus of 1.07 cm versus 0.75 cm (p<0.001) and average width of urethral meatus of 0.59 cm versus 0.38 cm (p<0.001). Considering the morphology of the urethral meatus, we propose a new classification, in the following groups: (a) typical; (b) slit; (c) point-like; (d) horseshoe; and (e) megameatus. The point-like meatus was the one that most needed intervention, followed by the slit and the typical meatus (p<0.001). Conclusions. Point-like and slit-shaped urethral meatus, as well as reduced length and width of the urethral meatus, are the determining factors

    Molecular characterization of Mycobacterium bovis infection in cattle and buffalo in Amazon Region, Brazil

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    The aim of this study was to characterize Mycobacterium bovis from cattle and buffalo tissue samples, from two Brazilian states, and to analyse their genetic diversity by spoligotyping. Tissue samples from tuberculosis suspect animals, 57 in Amazonas State (12 cattle and 45 buffaloes) and six from Pará State (5 cattle and one buffalo) from slaughterhouses under State Veterinary Inspection, were isolated in culture medium Stonebrink. The positive cultures were confirmed by PCR and analysed by the spoligotyping technique and the patterns (spoligotypes) were identified and compared at the Mycobacterium bovis Spoligotype Database (http://www.mbovis.org/). There was bacterial growth in 44 (69.8%) of the tissues of the 63 animals, of which PCR for region of differentiation 4 identified 35/44 (79.5%) as Mycobacterium bovis. Six different spoligotypes were identified among the 35 Mycobacterium bovis isolates, of which SB0295, SB1869, SB0121 and SB1800 had already been described in Brazil, and SB0822 and SB1608 had not been described. The most frequent spoligotype in this study (SB0822) had already been described in buffaloes in Colombia, a neighbouring country of Amazonas state. The other identified spoligotypes were also described in other South American countries, such as Argentina and Venezuela, and described in the Brazilian states of Rio Grande do Sul, Santa Catarina, São Paulo, Minas Gerais, Mato Grosso do Sul, Mato Grosso and Goiás, indicating an active movement of Mycobacterium bovis strains within Brazil.Instituto de BiotecnologíaFil: Carneiro, Paulo A. M. Michigan State University. Center for Comparative Epidemiology; Estados UnidosFil: Pasquatti, Taynara N. Dom Bosco Catholic University; BrasilFil: Takatani, Haruo. Agencia de Defesa Agropecuaria do Amazonas; BrasilFil: Zumarraga, Martin Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Marfil, Maria Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Barnard, Christian. Agencia de Defesa Agropecuaria do Amazonas; BrasilFil: Fitzgerald, Scott D. Michigan State University. Veterinary Diagnostic Laboratory; Estados UnidosFil: Abramovitch, Robert B. Michigan State University. Department of Microbiology and Molecular Genetics; Estados UnidosFil: Araujo, Flabio Ribeiro de. Centro Nacional de Pesquisa de Gado de Corte; BrasilFil: Kaneene, John B. Michigan State University. Center for Comparative Epidemiology; Estados Unido

    Chromosome differentiation patterns during cichlid fish evolution

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    <p>Abstract</p> <p>Background</p> <p>Cichlid fishes have been the subject of increasing scientific interest because of their rapid adaptive radiation which has led to an extensive ecological diversity and their enormous importance to tropical and subtropical aquaculture. To increase our understanding of chromosome evolution among cichlid species, karyotypes of one Asian, 22 African, and 30 South American cichlid species were investigated, and chromosomal data of the family was reviewed.</p> <p>Results</p> <p>Although there is extensive variation in the karyotypes of cichlid fishes (from 2n = 32 to 2n = 60 chromosomes), the modal chromosome number for South American species was 2n = 48 and the modal number for the African ones was 2n = 44. The only Asian species analyzed, <it>Etroplus maculatus</it>, was observed to have 46 chromosomes. The presence of one or two macro B chromosomes was detected in two African species. The cytogenetic mapping of 18S ribosomal RNA (18S rRNA) gene revealed a variable number of clusters among species varying from two to six.</p> <p>Conclusions</p> <p>The karyotype diversification of cichlids seems to have occurred through several chromosomal rearrangements involving fissions, fusions and inversions. It was possible to identify karyotype markers for the subfamilies Pseudocrenilabrinae (African) and Cichlinae (American). The karyotype analyses did not clarify the phylogenetic relationship among the Cichlinae tribes. On the other hand, the two major groups of Pseudocrenilabrinae (tilapiine and haplochromine) were clearly discriminated based on the characteristics of their karyotypes. The cytogenetic mapping of 18S ribosomal RNA (18S rRNA) gene did not follow the chromosome diversification in the family. The dynamic evolution of the repeated units of rRNA genes generates patterns of chromosomal distribution that do not help follows the phylogenetic relationships among taxa. The presence of B chromosomes in cichlids is of particular interest because they may not be represented in the reference genome sequences currently being obtained.</p

    Deep neural network-estimated electrocardiographic age as a mortality predictor

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    The electrocardiogram (ECG) is the most commonly used exam for the evaluation of cardiovascular diseases. Here we propose that the age predicted by artificial intelligence (AI) from the raw ECG (ECG-age) can be a measure of cardiovascular health. A deep neural network is trained to predict a patient’s age from the 12-lead ECG in the CODE study cohort (n = 1,558,415 patients). On a 15% hold-out split, patients with ECG-age more than 8 years greater than the chronological age have a higher mortality rate (hazard ratio (HR) 1.79, p < 0.001), whereas those with ECG-age more than 8 years smaller, have a lower mortality rate (HR 0.78, p < 0.001). Similar results are obtained in the external cohorts ELSA-Brasil (n = 14,236) and SaMi-Trop (n = 1,631). Moreover, even for apparent normal ECGs, the predicted ECG-age gap from the chronological age remains a statistically significant risk predictor. These results show that the AI-enabled analysis of the ECG can add prognostic information

    Controlo mecânico de infestantes

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    As infestantes são plantas indesejáveis que crescem juntamente com as plantas cultivadas e que interferem no seu desenvolvimento normal. As infestantes podem ser uma das principais causas da diminuição do rendimento das culturas, porque competem com elas para o espaço, para a água, luz solar, nutrientes e dióxido de carbono, podem segregar substâncias alelopáticas, ser o meio no qual temporariamente se instalam alguns organismos responsáveis por inúmeras pragas e doenças que atacam as culturas dificultando assim o combate às mesmas, dificultam a colheita quer esta seja manual ou mecanizada, podem contaminar o produto final, depreciando-o e, asseguram a reinfestação para as culturas seguintes. O controlo de infestantes ter-se-á iniciado quando o homem deixou a de ser nómada e de assegurar as suas necessidades através da colheita de frutos e da caça e passou após a “domesticação“ das espécies animais e vegetais a fazer agricultura, tornando-se sedentário. Portanto, desde o início da agricultura, que o homem tem feito grandes esforços para controlar as plantas infestantes, primeiro à mão, depois com o uso de alguns artefactos, ferramentas e equipamentos para melhorar a eficiência no seu controlo. Hoje existem equipamentos mecânicos sofisticados tal como, substâncias químicas ou biológicas que permitem o seu controlo prevenindo ou retardando a sua germinação ou crescimento. Interferência das plantas infestantes com a cultura pode gerar perdas significativas, na qualidade e quantidade de alimentos produzidos, desperdiçando enormes quantidades de energia, especialmente não renováveis. Os custos no controlo e os efeitos sobre os rendimentos são muito variáveis, dependendo do agricultor, das espécies de plantas infestantes e da estratégia ou estratégias adoptadas para garantir a eficácia no controlo. Nas últimas cinco décadas têm vindo a fazer-se significativos avanços científicos e tecnológicos na criação de estratégias para o aumento da eficácia no controlo de infestantes seja mecanicamente, seja através da utilização de substâncias químicas ou biológicas menos tóxicas para o homem, menos agressivas ao meio ambiente, com menores custos de produção e ao mesmo tempo, mais selectivas para as culturas onde são aplicadas. A alternativa ao controlo químico de infestantes através da aplicação de herbicidas é o controlo mecânico pela utilização de diversas alfaias agrícolas, tais como a charrua de aivecas, a charrua de discos, o escarificador de braços rígidos, o escarificador de braços flexíveis (vibrocultor) e a fresa. O controlo mecânico de infestantes poderá ser levado a cabo também por máquinas de corte, como por exemplo, as gadanheiras. Cortar as infestantes numa fase de desenvolvimento antes da produção de semente evita a sua propagação. Se o agricultor optar pela sementeira directa como técnica de instalação das culturas, a única alternativa que tem para o controlo de infestantes é a química, mas se optar pelo sistema de mobilização tradicional ou pela mobilização reduzida poderá controlar as infestantes, química e/ou mecanicamente. A eficácia das diferentes alfaias no controlo de infestantes depende da própria alfaia, da época do ano em que se realiza esse controlo, do estado do solo, das espécies de infestantes presentes e seu estádio de desenvolvimento. Iremos no presente trabalho, referir os aspectos mais importantes do controlo mecânico de infestantes

    Major electrocardiographic abnormalities according to the Minnesota coding system among Brazilian adults (from the ELSA-Brasil cohort study)

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    The electrocardiogram is a simple and useful clinical tool; nevertheless, few studies have evaluated the prevalence of electrocardiographic abnormalities in the Latin American population. This study aims to evaluate the major electrocardiographic abnormalities according to the Minnesota coding system in Brazilian adults, stratified by gender, age, race, and cardiovascular risk factors. Data from 14,424 adults (45.8% men, age 35 to 74 years) were obtained at baseline of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), according to standardized protocol. The electrocardiogram were obtained with the Burdick Atria 6100 machine, stored on Pyramis System, automatically coded according to the Minnesota coding system by the Glasgow University software and then manually revised. Major abnormalities were more prevalent in men than women (11.3% and 7.9%, p &lt;0.001). These differences were consistent through the different age groups, race, and number of cardiovascular risk factors. Electrocardiographic major abnormalities were more prevalent in black participants for both men (black: 15.1%, mixed: 10.4%, white: 11.1%, p = 0.001) and women (black: 10%, mixed: 7.6%, white: 7.2%, p = 0.004). In conclusion, in this large sample of Brazilian adults, the prevalence of major electrocardiographic abnormalities was higher among men, the elderly, black, and among people with more cardiovascular risk factors
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