591 research outputs found

    On the way for a better methodology in teaching/learning instrumentation for measurements at mechanical engineering Compulsory Syllabus

    Get PDF
    Instrumentation for Measurements is a course of 3rd year, 2nd semester, in the 5-year Mechanical Engineering degree, run at Faculty of Engineering of University of Porto (FEUP) under the responsibility of the first author, in which around 60% of the time is devoted to 'hands on' laboratory activity, involving a large number of students.The teachers team of this course has a broad rangecurricular training, not only in their different degrees butalso in several post graduate fields of specialisation. Thisbrings a transversal perspective, which is very importantwhen dealing with the teaching/learning of multidisciplinary matters.Continuous (theoretical and experimental) assessment hasbeen used during the last 4 years. It has been carefullyplaned and programmed at the very beginning of thesemester, exploring different student capabilities, eitherindividually or in group.This paper presents the methodologies that were used andcomments their advantages and disadvantages.Index Terms - Teaching/learning methodologies, hands onlaboratory, continuous assessment, experimental training

    Coeval perpendicular shortenings in the Brasilia belt : collision of irregular plate margins leading to oroclinal bending in the Neoproterozoic of central Brazil

    Get PDF
    The three belts which form the Tocantins province (central Brazil) records Neoproterozoic-EoPaleozoic collisions involving the Amazon and São Francisco paleocontinents and the Paraná continental block. The Brasília belt is a typical orocline bended around the WNW—ESE striking Pirineus Zone of High Strain (PZHS) and is comprised of the NE-trending (northern) and SE-trending (southern) segments. The Brasília dome is an N—S elliptical structural window situated in the center of the belt, at the eastern end of the PZHS. It evidences Di— D₂ and D₃ɴ shortenings (~ 750—590 Ma) due to ocean closure and Amazon- São Francisco collision following a WNW—ESE path, and demonstrates similar evolution for both segments of the belt. However, in the southern segment, D₁—D₂ structures are deformed by shortening in the SW-NE direction (D₃S). New data demonstrating D₁—D₂ and D₃ɴ tectonites deformed by D₃S struc- tures in the area close to the dome's SW margin and SE of the PZHS support understanding the Brasília belt and oroclinal bending as a consequence of the collision of two (Amazon and São Francisco) irregular continental margins leading to separation-rotation of the Paraná block from the Amazon paleocontinent and the Paraná-São Francisco collision

    Natural variation of arsenic fractions in soils of the Brazilian Amazon

    Get PDF
    Arsenic (As) in native soils of the Amazon rainforest is a concern due to its likely origin from the Andean rivers, which transport loads of sediments containing substantial amounts of trace elements coming from the cordilleras. Yet, unveiling soil As baseline concentrations in the Amazon basin is still a need because most studies in Brazil have been performed in areas with predominantly high concentrations and cannot express a real baseline value for the region. In this study, 414 soil samples (0–20, 20–40 and 40–60 cm layers) were collected from different sites throughout the Amazon basin - including native Amazon rainforest and minimally disturbed areas - and used to determine total and extractable (soluble + available) As concentrations along with relevant soil physicochemical properties. Descriptive statistics of the data was performed and Pearson correlation supported by a Principal Component Analysis (PCA) provided an improved understanding of where and how As concentrations are influenced by soil attributes. Total As concentration ranged from 0.98 to 41.71 mg kg−1 with values usually increasing from the topsoil (0–20 cm) to the deepest layer (40–60 cm) in all sites studied. Considering the proportional contribution given by each fraction (soluble and available) on extractable As concentration, it is noticeable that KH2PO4-extractable As represents the most important fraction, with >70% of the As extracted on average in all the sites studied. Still, the extractable fractions (soluble + available) correspond to ~0.24% of the total As, on average. Total, available, and soluble As fractions were strongly and positively correlated with soil Al3+. The PCA indicated that soil pH in combination with CEC might be the key factors controlling soil As concentrations and the occurrence of each arsenic fraction in the soil layers

    VITAMINA D E SUA CORRELAÇÃO COM FATORES DE RISCO CARDIOVASCULAR

    Get PDF
    A vitamina D é conhecida por regular a concentração óssea e sérica de cálcio. No entanto, emergiu nos últimos anos uma crise de hipovitaminose D, devido à diminuição da exposição solar e, conjuntamente um aumento de doenças cardiovasculares (DCV). Esse resumo expandido visa abordar os estudos já realizados sobre o assunto, bem como aproximar uma conclusão baseada na análise crítica de alguns artigos e metas-análises

    DIABETES MELLITUS GESTACIONAL: REVISÃO DE LITERATURA

    Get PDF
    O Diabetes Mellitus Gestacional (DMG) é definido como qualquer intolerância à glicose, com magnitude variável, de início ou diagnóstico durante a gestação, segundo a Sociedade Brasileira de Diabetes (SBD). O objetivo do presente estudo é analisar a epidemiologia, o diagnóstico e tratamento atuais. Tratou-se de uma revisão de literatura com consulta nas bases de dados PubMed e rima.org/core, utilizando-se os seguintes descritores: diabetes gestacional, epidemiologia, diagnóstico e tratamento, no período de 2000 a 2016. Concluiu-se que o DMG é um problema de saúde pública com prevalência elevada em gestantes com fatores de risco e sem consenso mundial quanto aos parâmetros de diagnóstico. A respeito do tratamento, o uso da metformina mostrou eficácia e segurança equivalentes à insulina em relação às intercorrências no binômio materno-fetal. Por conseguinte, nota-se a necessidade de atualização das diretrizes, com base em estudos de longo prazo para avaliação do uso da metformina como tratamento alternativo no controle glicêmico. Essa revisão de literatura visa sintetizar os estudos mais atuais sobre o assunto, bem como aproximar uma conclusão baseada na análise crítica de artigos e meta-análises

    Esterase activity in homogenates of Helicoverpa armigera (Hubner) (Lepidoptera: noctuidae) exposed to different insecticides and the behavioral effect

    Get PDF
    The toxicity of some insecticides to Helicoverpa armigera was studied through sublethal effects, evaluating the enzymatic activity of esterase and the behavioral response. The commercial formulation of insecticides selected were chlorpyrifos, spinosad, indoxacarb, chlorantraniliprole, lambda-cyhalothrin and Bacillus thuringiensis, corresponding the most used by farmers to control of H. armigera. To determine the esterase activity, the larvae were fed with soybean leaf discs dipped in insecticide solution using the lethal concentration (LC50). For the behavioral response, filter paper were immersed in three concentrations of insecticides (LC50, LC95 and recommend dose.), then the behavior of the larvae observed in Videomex-One. The results for the enzymatic activity showed an increase in the activity of the esterase, with variation along the treatments and the time of exposure of the insects to the insecticides. With exception of spinosad, other insecticides showed an increase in EST-α activity, 6 and 24 hours after contact of caterpillars with insecticide.Different behavioral patterns of walking (walking distance, walking speed and resting time) were observed for H. armigera exposed to different insecticides. H. armigera exposed to chlorpyrifos, lambda-cyhalothrin and B. thuringiensis insecticides show greater esterase activity. Regarding walking behavior, the results confirms enzymatic activity, where H. armigera have behavioral alteration after exposure to insecticide

    Zebrafish (Danio rerio) meets bioethics: the 10Rs ethical principles in research

    Get PDF
    Zebrafish (Danio rerio) is a tropical fish species widely used in research, worldwide. The development of genetically modified animals and the increasing number of zebrafish breeding facilities due to their emerging use in several research fields, opened room for new ethical challenges for research carried out with this species. It is necessary to raise the scientific community’s awareness of the ethical standards and laws in force, on animal research. Thus, the aim of the current study is to describe 10 Rs ethical principles by using zebrafish as model system in research. The classical 3 Rs concerning animal welfare, namely replacement, reduction and refinement; and the added 7 Rs related to scientific (registration, reporting, robustness, reproducibility and relevance) and conduct principles (responsibility, and respect) in zebrafish research are herein presented and critically discussed. The use of these 10 Rs by researchers, institutions and the Animal Ethics Committee is recommended to support regulations, decision-making about and the promotion of zebrafish health and welfare in research. Keywords: animal health; animal welfare; animal ethics committees; fish; laboratory animals

    Natural variation of arsenic fractions in soils of the Brazilian Amazon

    Get PDF
    Arsenic (As) in native soils of the Amazon rainforest is a concern due to its likely origin from the Andean rivers, which transport loads of sediments containing substantial amounts of trace elements coming from the cordilleras. Yet, unveiling soil As baseline concentrations in the Amazon basin is still a need because most studies in Brazil have been performed in areas with predominantly high concentrations and cannot express a real baseline value for the region. In this study, 414 soil samples (0–20, 20–40 and 40–60 cm layers) were collected from different sites throughout the Amazon basin - including native Amazon rainforest and minimally disturbed areas - and used to determine total and extractable (soluble + available) As concentrations along with relevant soil physicochemical properties. Descriptive statistics of the data was performed and Pearson correlation supported by a Principal Component Analysis (PCA) provided an improved understanding of where and how As concentrations are influenced by soil attributes. Total As concentration ranged from 0.98 to 41.71 mg kg−1 with values usually increasing from the topsoil (0–20 cm) to the deepest layer (40–60 cm) in all sites studied. Considering the proportional contribution given by each fraction (soluble and available) on extractable As concentration, it is noticeable that KH2PO4-extractable As represents the most important fraction, with >70% of the As extracted on average in all the sites studied. Still, the extractable fractions (soluble + available) correspond to ~0.24% of the total As, on average. Total, available, and soluble As fractions were strongly and positively correlated with soil Al3+. The PCA indicated that soil pH in combination with CEC might be the key factors controlling soil As concentrations and the occurrence of each arsenic fraction in the soil layers

    Acesso a Tratamento Endovascular para Acidente Vascular Cerebral Isquémico em Portugal

    Get PDF
    Introduction: Since the publication of endovascular treatment trials and European Stroke Guidelines, Portugal has re-organized stroke healthcare. The nine centers performing endovascular treatment are not equally distributed within the country, which may lead to differential access to endovascular treatment. Our main aim was to perform a descriptive analysis of the main treatment metrics regarding endovascular treatment in mainland Portugal and its administrative districts. Material and methods: A retrospective national multicentric cohort study was conducted, including all ischemic stroke patients treated with endovascular treatment in mainland Portugal over two years (July 2015 to June 2017). All endovascular treatment centers contributed to an anonymized database. Demographic, stroke-related and procedure-related variables were collected. Crude endovascular treatment rates were calculated per 100 000 inhabitants for mainland Portugal, and each district and endovascular treatment standardized ratios (indirect age-sex standardization) were also calculated. Patient time metrics were computed as the median time between stroke onset, first-door, and puncture. Results: A total of 1625 endovascular treatment procedures were registered. The endovascular treatment rate was 8.27/100 000 inhabitants/year. We found regional heterogeneity in endovascular treatment rates (1.58 to 16.53/100 000/year), with higher rates in districts closer to endovascular treatment centers. When analyzed by district, the median time from stroke onset to puncture ranged from 212 to 432 minutes, reflecting regional heterogeneity. Discussion: Overall endovascular treatment rates and procedural times in Portugal are comparable to other international registries. We found geographic heterogeneity, with lower endovascular treatment rates and longer onset-to-puncture time in southern and inner regions. Conclusion: The overall national rate of EVT in the first two years after the organization of EVT-capable centers is one of the highest among European countries, however, significant regional disparities were documented. Moreover, stroke-onset-to-first-door times and in-hospital procedural times in the EVT centers were comparable to those reported in the randomized controlled trials performed in high-volume tertiary hospitals.info:eu-repo/semantics/publishedVersio
    corecore