1,737 research outputs found

    Limitations posed by free DEMs in watershed studies: The case of river Tanaro in Italy

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    Topography is a critical element in the hydrological response of a drainage basin and its availability in the form of digital elevation models (DEMs) has advanced the modeling of hydrological and hydraulic processes. However, progress experienced in these fields may stall, as intrinsic characteristics of free DEMs may limit new findings, while at the same time new releases of free, high-accuracy, global digital terrain models are still uncertain. In this paper, the limiting nature of free DEMs is dissected in the context of hydrogeomorphology. Ten sets of terrain data are analyzed: the SRTM GL1 and GL3, HydroSHEDS, TINITALY, ASTER GDEM, EU DEM, VFP, ALOS AW3D30, MERIT and the TDX. In specific, the influence of three parameters are investigated, i.e., spatial resolution, hydrological reconditioning and vertical accuracy, on four relevant geomorphic terrain descriptors, namely the upslope contributing area, the local slope, the elevation difference and the flow path distance to the nearest stream, H and D, respectively. The Tanaro river basin in Italy is chosen as the study region and the newly released LiDAR for the Italian territory is used as benchmark to reassess vertical accuracies. In addition, the EU-Hydro photo-interpreted river network is used to compare DEM-based river networks. Most DEMs approximate well the frequency curve of elevations of the LiDAR, but this is not necessarily reflected in the representation of geomorphic features. For example, DEMs with finer spatial resolution present larger contributing areas; differences in the slope can reach 10%; between 5 m and 12 m H, none of the considered DEMs can faithfully represent the LiDAR; D presents significant variability between DEMs; and river network extraction can be problematic in flatter terrain. It is also found that the lowest mean absolute error (MAE) is given by the MERIT, 2.85 m, while the lowest root mean square error (RMSE) is given by the SRTM GL3, 4.83 m. Practical implications of choosing a DEM over another may be expected, as the limitations of any particular DEM in faithfully reproducing critical geomorphic terrain features may hinder our ability to find satisfactory answers to some pressing problems

    A comparison of the Normal and Laplace distributions in the models of fuzzy probability distribution for portfolio selection

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    The propose of this work is applied the fuzzy Laplace distribution on a possibilistic mean-variance model presented by Li et al which appliehe fuzzy normal distribution. The theorem necessary to introduce the Laplace distribution in the model was demonstrated. It was made an analysis of the behavior of the fuzzy normal and fuzzy Laplace distributions on the portfolio selection with VaR constraint and risk-free investment considering real data. The results showns that were not difference in assets selection and in return rate, however, There was a change in the risk rate, which was higher in the Laplace distribution than in the normal distribution

    Predictive Modeling of Envelope Flood Extents Using Geomorphic and Climatic-Hydrologic Catchment Characteristics

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    A topographic index (flood descriptor) that combines the scaling of bankfull depth with morphology was shown to describe the tendency of an area to be flooded. However, this approach depends on the quality and availability of flood maps and assumes that outcomes can be directly extrapolated and downscaled. This work attempts to relax these problems and answer two questions: (1) Can functional relationships be established between a flood descriptor and geomorphic and climatic-hydrologic catchment characteristics? (2) If so, can they be used for low-complexity predictive modeling of envelope flood extents? Linear stepwise and random forest regressions are developed based on classification outcomes of a flood descriptor, using high-resolution flood modeling results as training benchmarks, and on catchment characteristics. Elementary catchments of four river basins in Europe (Thames, Weser, Rhine, and Danube) serve as training data set, while those of the Rh\uf4ne river basin in Europe serve as testing data set. Two return periods are considered, the 10- and 10,000-year. Prediction of envelope flood extents and flood-prone areas show that both models achieve high hit rates with respect to testing benchmarks. Average values were found to be above 60% and 80% for the 10- and the 10,000-year return periods, respectively. In spite of a moderate to high false discovery rate, the critical success index value was also found to be moderate to high. It is shown that by relating classification outcomes to catchment characteristics, the prediction of envelope flood extents may be achieved for a given region, including ungauged basins

    Intrahepatic Colangiocarcinoma

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    Introdução: o colangiocarcinoma intra-hepático (CCIhp) é um tumor maligno raro, normalmente diagnosticado num estadio avançado. São objectivos deste estudo avaliar os resultados da terapêutica do CCIhp e os factores prognósticos com significado estatístico na sobrevida de doentes com esta entidade nosológica tratados no nosso Serviço. Material e métodos: Vinte e um doentes submetidos a tratamento por CCIhp nos últimos anos, dos quais onze foram operados com intuitos curativos: quatro hepatectomias esquerdas, duas hepatectomias esquerdas alargadas aos segmentos V e VIII, duas hepatectomias direitas, duas bissegmentectomias e uma trissegmentectomia. Resultados: a mortalidade per-operatória foi de 0% e a pós-operatória (três meses) de 6%. As sobrevidas cumulativas aos 5 anos foram de 14% no total da população, 26% nos doentes submetidos a cirurgia com intuitos curativos e 26% para a sobrevida cumulativa livre de doença. Observou-se recidiva tumoral hepática em cinco doentes, a qual ocorreu aos 1,09 ± 0,82 anos (limites: 0,24-2,08). Os factores que influenciaram a sobrevida da globalidade dos doentes foram o tratamento cirúrgico com intuitos curativos (p=0,028), a presença de invasão vascular (p=0,002) e o valor da fosfatase alcalina no momento do diagnóstico (p=0,044). Entre os doentes operados com intuitos curativos, a presença de invasão vascular influenciou a sobrevida global (p=0,025) e a sobrevida livre de doença (p=0,002). Conclusões: A ressecção cirúrgica com intuitos curativos aumentou, de forma estatisticamente significativa, a sobrevida dos doentes com CCIhp. No entanto, sendo o diagnóstico geralmente tardio, apenas uma pequena percentagem destes doentes pode beneficiar deste tratamento.info:eu-repo/semantics/publishedVersio

    New system based on image processing and analysis techniques for Vickers and Brinell hardness semi-automatic measurement

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    Mechanical tests for measurement of hardness are fundamental to evaluate some metallicmaterials properties, like wear resistance, ductility and flow tension. The manual processfor hardness measurement is very interpretive and subjective, as the reading of neededvalues (diameters or diagonals) of the indenter on the material in test depends directly onoperators viewpoint (parallax effect), appropriate calibration of test machine andoperators experience. Additionally, one must notice that operators fatigue or tiredness,due to a high number of tests done, is highly prone to measurement errors.In this context, the main goals of this work were the development and analyze of a semiautomaticsystem, based on image analysis and processing techniques, able to determine theVickers and Brinell hardness values from indentation images. The results obtained usingthe system developed were compared with those obtained by the conventional manualprocess. From this comparison, one could conclude that the system developed obtainedmore accurate and faster result

    Vinculação da Mulher como Preditor da Dor Durante o Parto e Após o Nascimento: um Estudo Observacional Prospectivo

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    INTRODUCTION: Labour is considered to be one of the most painful and significant experiences in a woman's life. The aim of this study was to examine whether women's attachment style is a predictor of the pain experienced throughout labour and post-delivery. MATERIAL AND METHODS:Thirty-two pregnant women were assessed during the third trimester of pregnancy and during labour. Adult attachment was assessed with the Adult Attachment Scale ' Revised. The perceived intensity of labour pain was measured using a visual analogue scale for pain in the early stage of labour, throughout labour and post-delivery. RESULTS:Women with an insecure attachment style reported more pain at 3 cm of cervical dilatation (p < 0.05), before the administration of analgesia (p < 0.01) and post-delivery (p < 0.05) than those securely attached. In multivariate models, attachment style was a significant predictor of labour pain at 3 cm of cervical dilatation and before the first administration of analgesia but not of the perceived pain post-delivery. DISCUSSION: These findings confirm that labour pain is influenced by relevant psychological factors and suggest that a woman's attachment style may be a risk factor for greater pain during labour. CONCLUSION:Future studies in the context of obstetric pain may consider the attachment style as an indicator of individual differences in the pain response during labour. This may have important implications in anaesthesiology and to promote a relevant shift in institutional practices and therapeutic procedures

    Using a distance map and an active contour model to segment the carotid artery boundary from the lumen contour in proton density weighted magnetic resonance images

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    Segmentation methods have assumed an important role in image-based diagnosis of several cardiovascular diseases. Particularly, the segmentation of the boundary of the carotid artery is demanded in the detection and characterization of atherosclerosis and assessment of the disease progression. In this article, a fully automatic approach for the segmentation of the carotid artery boundary in Proton Density Weighted Magnetic Resonance Images is presented. The approach relies on the expansion of the lumen contour based on a distance map built using the gray-weighted distance relative to the center of the identified lumen region in the image under analysis. Then, a Snake model with a modified weighted external energy based on the combination of a balloon force along with a Gradient Vector Flow-based external energy is applied to the expanded contour towards the correct boundary of the carotid artery. The average values of the Dice coefficient, Polyline distance, mean contour distance and centroid distance found in the segmentation of 139 carotid arteries were 0.83 ± 0.11, 2.70 ± 1.69 pixels, 2.79 ± 1.89 pixels and 3.44 ± 2.82 pixels, respectively. The segmentation results of the proposed approach were also compared against the ones obtained by related approaches found in the literature, which confirmed the outstanding performance of the new approach. Additionally, the proposed weighted external energy for the Snake model was shown to be also robust to carotid arteries with large thickness and weak boundary image edges. (c) 202

    Diagnóstico da pecuária em Rondônia.

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    Aspectos gerais sobre Rondônia: tipos de exploração; estrutura fundiária; infra-estrutura de apoio a produção; pesquisa e assistência técnica; rebanho bovino; Pecuária de leite: produção estadual, industrialização, oferta e demanda de leite do estado, regições produtoras, prognóstico; Pecuária de corte: constituição do rebanho de corte, abates e produção de carne, comercialização do gado, matadouros, frigoríficos, regões de pecuária de corte; Bufalos: rebanho, estrutura das propriedades, comercialização e prognóstico.bitstream/item/60569/1/DOC-19470001.pd
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