Assessing aerodynamic flutter instability in prismatic structures with rectangular cross sections

Neste artigo estuda-se a ocorrência de instabilidade aerodinâmica por 'flutter' em estruturas prismáticas esbeltas de secção retangular. Considera-se um modelo com 2 graus de liberdade e obtém-se a sua formulação adimensional identificando-se um número mínimo de parâmetros adimensionais que regem a ocorrência de instabilidade por 'flutter' . Obtém-se uma muito boa concordância entre os resultados do modelo de 2 graus de liberdade e os resultados existentes na literatura. Este artigo tem 2 objetivos: (i) definir as condições para as quais estruturas esbeltas com secções retangulares podem instabilizar por 'flutter' sob a ação do vento e (ii) fornecer uma coleção alargada de resultados sob a forma de tabelas ou gráficos prontos a usar, cobrindo um largo número de casos, que proporciona aos projetistas de estruturas uma ferramenta que estes podem utilizar, a nível de pré-dimensionamento, para prever as velocidades críticas do vento que provocam a instabilidade por 'flutter' .This paper is dedicated to the study of the occurrence of 'flutter' instability in slender prismatic structures of rectangular cross section. A two degree of freedom model is considered and its non dimensional formulation is derived so that a minimum number of non dimensional parameters governing the occurrence of 'flutter' instability are put in evidence. A very good agreement has been obtained by comparing the results of the two degree of freedom model with the results available in the literature. The goal of this document is twofold: (i) to summarize the conditions for which slender structures with rectangular cross sections may get unstable by 'flutter' under the action of steady wind conditions and (ii) to supply a broad collection of data in the form of ready-to-use tables or graphics covering a wide range of cases, that provide a basis for designers to predict the critical wind velocities at the onset of 'flutter' instability.Peer Reviewe

Alterações na actividade enzimática da amílase salivar em indivíduos obesos

Nos últimos anos o estudo da composição proteica da saliva ganhou interesse pelo seu potencial no diagnóstico não invasivo e compreensão de diversas doenças, quer orais, quer sistémicas. Para além disso, a interacção deste fluido com os constituintes dos alimentos tornam a sua análise importante para a compreensão das variações a nível da percepção dos alimentos e escolhas alimentares. Há, contudo, poucos estudos que comparem a composição proteica da saliva de indivíduos obesos com indivíduos normoponderais. Uma das proteínas mais abundante na saliva é a α-amilase. Esta proteína é responsável pelo início da digestão de hidratos de carbono na boca influenciando a percepção dos alimentos. Para além disso, os seus níveis são indicadores do funcionamento das glândulas salivares, tendo ainda sido sugerida como potencial marcador de condições de stress e de actividade do sistema nervoso simpático. O presente trabalho teve como objectivo comparar os níveis de α-amilase salivar entre indivíduos obesos (IMC>30; N=10) e normoponderais (IMC<25; N=10) do sexo feminino. Foram feitas recolhas de saliva mista, na ausência de estimulação e sempre à mesma hora do dia. Para determinar a actividade enzimática da α-amilase utilizou-se um kit colorimétrico (Sentinel Diagnostics). Foi observada uma maior actividade enzimática de α-amilase nos indivíduos obesos comparativamente aos normoponderais (243,2 X 103 ± 37,7 X 103 e 106,1 X 103 ± 44,2 X 103 U/L, respectivamente) A maior actividade enzimática da α-amilase poderá contribuir para alterações na percepção dos alimentos, nomeadamente no que diz respeito ao gosto doce dos hidratos de carbono. Uma diferente sensibilidade gustativa poderá ter influências nas escolhas alimentares. Estes resultados reforçam a importância de estudos mais aprofundados acerca da função salivar e percepção gustativa na obesidade

A case study for a multitemporal segmentation approach in optical remote sensing images.

Continuous observations from remote sensors provide high temporal and spatial resolution imagery, and better remote sensing image segmentation techniques are mandatory for efficient analysis. Among them, one of the most applied segmentation techniques is the region growing algorithm. Within this context, this paper describes a study case for a multitemporal segmentation that adapts the traditional region growing technique. Our method aims to detect homogeneous regions in space and time observing a sequence of optical remote sensing images. Tests were conducted by considering the Dynamic Time Warping distance as the homogeneity criterion to grow regions. A case study on high temporal resolution for sequences of Landsat-8 vegetation indices products provided satisfactory outputs.GEOProcessing 2018

Cartas de isoietas mensais para as bacias hidrográficas dos rios Tejo e Sado

Presentation of the monthly isohyet map for the Tagus and Sado river basins. Isohyet lines data were plotted from 93 000 records, collected during a 42 year's observation period in 185 climatological stations, with the purpose of estimating the recharge of natural groundwater

Árvore decisória para o controle da mastite bovina em fazenda leiteira no Pantanal.

A mastite é um processo inflamatório da glândula mamária acompanhado da redução de secreção de leite. Bactérias são, como o Staphylococcus aureus, consideradas patógeno primário e tem sido o agente isolado mais freqüentemente tanto de infecções clínicas como subclínicas. O sistema APPCC é uma abordagem sistemática para controlar potenciais perigos na produção de alimentos. É um instrumento útil para avaliar perigos e estabelecer mecanismos de controle, sempre privilegiando a prevenção. O presente estudo teve como objetivo elaborar uma arvore decisória para auxiliar na tomada de decisão no controle de mastite usando princípios da análise de perigos em pontos críticos de controle em uma fazenda leiteira, do Pantanal.bitstream/item/37490/1/CT46.pd

Selection criteria for weighting factor in linear regression

Poster apresentado no 54th Annual meeting of the International Association of Forensic Toxicologists (TIAFT) 28 de agosto - 1 setembro 2016, Brisbane, AustraliaN/

Serum serotonin levels and bone in rheumatoid arthritis patients

In rheumatoid arthritis (RA), a disease characterized by bone loss, increased levels of serotonin have been reported. Recent studies have demonstrated a role for circulating serotonin as a regulator of osteoblastogenesis, inhibiting bone formation. Thus, we measured serum serotonin levels (SSL) in a Portuguese sample of 205 RA patients and related these to anthropometric variables, disease parameters, serum bone biomarkers, and bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry at several sites (total proximal femur, lumbar spine, left hand, and left second proximal phalange). SSL were inversely associated with body mass index (BMI) in RA women (r = − 0.218; p = 0.005), independent of exposure to biologics and/or bisphosphonates. Among biologic naïves, there was an inverse association between SSL and osteoprotegerin in RA women (r = − 0.260; p = 0.022). Serum β-CTX and dickkopf-1 were strongly associated with SSL in RA men not treated with bisphosphonates (r = 0.590; p < 0.001/r = 0.387; p = 0.031, respectively). There was also an inverse association between SSL and sclerostin in RA men (r = − 0.374; p < 0.05), stronger among biologic naïve or bisphosphonates-unexposed RA men. In crude models, SSL presented as a significant negative predictor of total proximal femur BMD in RA women as well as in postmenopausal RA women. After adjustment for BMI, disease duration, and years of menopause, SSL remained a significant negative predictor of total proximal femur BMD only in postmenopausal RA women. Our data reinforce a role, despite weak, for circulating serotonin in regulating bone mass in RA patients, with some differences in terms of gender and anatomical sites.Associação Nacional de Reumatologia, the study sponsor, had no role in the study design; in the collection, analysis, and interpretation of the data; in the writing of the report; and in the decision to submit the paper for publication

Paraquat Intoxication – experience of an Internal Medicine ward for 18 years

Introduction: Paraquat is a contact herbicide commercially available since 1962. Paraquat intoxication (PI) is usually voluntary and highly lethal, since there is no effective antidote. Toxicity occurs through cyclic redox reactions, damaging mainly the kidneys and lungs. Aim, material and methods: featuring the clinical presentation, management and outcome of patients with PI over an 18 years period (from the 01st January 1993 to the 31st December 2010) through the retrospective analysis of clinical files and comparing the survivors and the deceased. Results: Thirty-one cases of Paraquat intoxication were included, with a male: female ratio 1:1. Age range from 13 to 80 years, mean age 42.4years (±18.7).All intoxications were voluntary and by oral route. There was statistical difference in the amount ingested (22.1 mL vs. 72.7 mL, p<0.0005). A non-significant trend to a longer delay until getting medical attention in the deceased group (1.6 h vs. 3.2 h, p=0.091). Statistical significance was found between mortality and leukocytosis, hypocapnea, hypoxemia, LDH, alkaline phosphatase and AST. There was no difference between groups according to treatment options, although hemocarboperfusion was used more often in the deceased group (53.9% vs. 66.7%, p=0.471) and corticosteroids in the survivor group (61.5% vs. 44.4%, p=0.350). Mortality rate was 58.1% (66.7% in the first 72 hours), due to respiratory insufficiency and multiple organ failure. Variable levels of pulmonary fibrosis occurred in 38.5% of the survivors. Discussion & Conclusion: Paraquat intoxication has a poor prognosis with limited efficiency of treatment approaches. The relation between Paraquat in the urine and the time elapsed after ingestion is the main determinant factor in the prognosis. In this study the presence of dyspnea, hypocapnea and hypoxemia was linked to a bad prognosis. There was no statistical difference between the available treatment options

Towards a high-resolution offshore wind Atlas : the Portuguese case

ABSTRACT: An accurate offshore wind resource assessment is a key tool for planning marine wind renewable exploitation. To achieve this goal, without resort to an extensive and costly network of anemometric stations or buoys, it becomes necessary to use the so-called atmospheric mesoscale models. This work presents a high spatial resolution (1x1 km) offshore wind resource Atlas for Portugal and the model calibration steps. During the calibration steps, the most adequate: i) atmospheric parameterizations - physics options, ii) initial and boundary conditions (IBC) meteorological datasets, and iii) data assimilation scheme were achieved through sensitivity tests using the common statistical metrics and hourly simulated/observational data. Results show that the most significant improvements are associated with the IBC dataset and the data assimilation scheme used. Thus, the results show that the assimilation procedures coupled with the new ERA-5 reanalysis dataset reduce significantly the errors of the wind speed and direction, especially the normalized mean square error. This reduction, depending on the different calibration setup, can be above 50%. The new Atlas confirms the previous indicators, Portugal presents a high wind power potential, especially for deep offshore regions.info:eu-repo/semantics/publishedVersio