334 resultados para Lightning Bolt
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Serum hepatitis B virus (HBV) DNA [eve[ is a predictor of the development of cirrhosis and hepatocellullar carcinoma in chronic hepatitis B patients. Nevertheless, the distribution of viral load levels in chronic HBV patients in Brazil has yet to be described. This cross-sectional study included 564 participants selected in nine Brazilian cities located in four of the five regions of the country using the database of a medical diagnostics company. Admission criteria included hepatitis B surface antigen seropositivity, availability of HBV viral toad samples and age >= 18 years. Mates comprised 64.5% of the study population. Mean age was 43.7 years. Most individuals (62.1%) were seronegative for the hepatitis B e antigen (HBeAg). Median serum ALT level was 34 U/L. In 58.5% of the patients HBV-DNA levels ranged from 300 to 99,999 copies/mL; however, in 21.6% levels were undetectable. Median HBV-DNA level was 2,351 copies/mL. Over 60% of the patients who tested negative for HBeAg and in whom ALT level was less than 1.5 times the upper limit of the normal range had HBV-DNA levels > 2,000 IU/mL, which has been considered a cut-off point for indicating a liver biopsy and/or treatment. In conclusion, HBV-DNA level identified a significant proportion of Brazilian individuals with chronic hepatitis B at risk of disease progression. Furthermore, this tool. enables those individuals with high HBV-DNA levels who are susceptible to disease progression to be identified among patients with normal or stightly elevated ALT.
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No Abstract
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A numerical modelling strategy has been developed in order to quantify the magnitude of induced stresses at the boundaries of production level and undercut level drifts for various in situ stress environments and undercut scenarios. The results of the stress modelling were in line with qualitative experiential guidelines and a limited number of induced stress measurements documented from caving sites. A number of stress charts were developed which quantify the maximum boundary stresses in drift roofs for varying in situ stress regimes, depths and undercut scenarios. This enabled many of the experiential guidelines to be quantified and bounded. A limited number of case histories of support and support performance in cave mine drifts were compared to support recommendations using the NGI classification system, The stress charts were used to estimate the Stress Reduction Factor for this system. The back-analyses suggested that the NGI classification system might be able to give preliminary estimates of support requirements in caving mines with modifications relating to rock bolt length and the support of production level intersections. (C) 2002 Elsevier Science Ltd. All rights reserved.
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Background: Regulating mechanisms of branching morphogenesis of fetal lung rat explants have been an essential tool for molecular research. This work presents a new methodology to accurately quantify the epithelial, outer contour and peripheral airway buds of lung explants during cellular development from microscopic images. Methods: The outer contour was defined using an adaptive and multi-scale threshold algorithm whose level was automatically calculated based on an entropy maximization criterion. The inner lung epithelial was defined by a clustering procedure that groups small image regions according to the minimum description length principle and local statistical properties. Finally, the number of peripheral buds were counted as the skeleton branched ends from a skeletonized image of the lung inner epithelial. Results: The time for lung branching morphometric analysis was reduced in 98% in contrast to the manual method. Best results were obtained in the first two days of cellular development, with lesser standard deviations. Non-significant differences were found between the automatic and manual results in all culture days. Conclusions: The proposed method introduces a series of advantages related to its intuitive use and accuracy, making the technique suitable to images with different lightning characteristics and allowing a reliable comparison between different researchers.
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A concepção de instalações eléctricas deve garantir condições de segurança para as pessoas e equipamentos. Para tal é exigida, quer por força de regulamentação ou de normalização, a instalação de dispositivos que garantam a detecção e a protecção contra os defeitos mais comuns nas instalações eléctricas como, por exemplo, as sobreintensidades e as sobretensões. Susceptíveis de criar sobretensões perigosas nas instalações eléctricas, as descargas atmosféricas podem ainda causar danos estruturais elevados, o que, em algumas actividades económicas, torna fundamental a implementação de medidas de protecção contra este fenómeno natural. A protecção contra descargas atmosféricas directas consiste em identificar as vulnerabilidades das estruturas e, nesses locais, implementar dispositivos de captura, direccionamento e escoamento da descarga atmosférica à terra, em condições de segurança. O presente trabalho, desenvolvido no âmbito da dissertação de Mestrado em Engenharia Electrotécnica, visa desenvolver e implementar uma ferramenta computacional, baseada em programas de desenho assistido por computador (CAD) de utilização corrente na área de projecto de arquitectura e de engenharia, que permita, no âmbito de normas internacionais, a análise e implementação de sistemas de protecção em edifícios contra descargas atmosféricas de uma forma rápida e expedita. Baseado num programa CAD 3D, que permite a modelização tridimensional das estruturas a proteger, a ferramenta desenvolvida tentará identificar as suas vulnerabilidades das estruturas às descargas atmosféricas directas, com o intuito de implementar as medidas de protecção mais adequadas do ponto de vista técnico económico. Prevê-se que a ferramenta resultante deste estudo, o Simulador do Modelo Electrogeométrico (SIMODEL), possibilite aos projectistas e particularmente aos alunos das unidades curriculares na área do projecto de instalações eléctricas da Área Departamental de Engenharia de Sistemas e Potencia e Automação (ADESPA) do ISEL, estudar e implementar sistemas de protecção contra descargas atmosféricas (SPDA) baseados na normalização internacional do CENELEC e da IEC, nomeadamente as normas da série 62305.
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Storm- and tsunami-deposits are generated by similar depositional mechanisms making their discrimination hard to establish using classic sedimentologic methods. Here we propose an original approach to identify tsunami-induced deposits by combining numerical simulation and rock magnetism. To test our method, we investigate the tsunami deposit of the Boca do Rio estuary generated by the 1755 earthquake in Lisbon which is well described in the literature. We first test the 1755 tsunami scenario using a numerical inundation model to provide physical parameters for the tsunami wave. Then we use concentration (MS. SIRM) and grain size (chi(ARM), ARM, B1/2, ARM/SIRM) sensitive magnetic proxies coupled with SEM microscopy to unravel the magnetic mineralogy of the tsunami-induced deposit and its associated depositional mechanisms. In order to study the connection between the tsunami deposit and the different sedimentologic units present in the estuary, magnetic data were processed by multivariate statistical analyses. Our numerical simulation show a large inundation of the estuary with flow depths varying from 0.5 to 6 m and run up of similar to 7 m. Magnetic data show a dominance of paramagnetic minerals (quartz) mixed with lesser amount of ferromagnetic minerals, namely titanomagnetite and titanohematite both of a detrital origin and reworked from the underlying units. Multivariate statistical analyses indicate a better connection between the tsunami-induced deposit and a mixture of Units C and D. All these results point to a scenario where the energy released by the tsunami wave was strong enough to overtop and erode important amount of sand from the littoral dune and mixed it with reworked materials from underlying layers at least 1 m in depth. The method tested here represents an original and promising tool to identify tsunami-induced deposits in similar embayed beach environments.
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Dissertação de Natureza Científica para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Estruturas
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The aim of this study is to evaluate lighting conditions and speleologists’ visual performance using optical filters when exposed to the lighting conditions of cave environments. A crosssectional study was conducted. Twenty-three speleologists were submitted to an evaluation of visual function in a clinical lab. An examination of visual acuity, contrast sensitivity, stereoacuity and flashlight illuminance levels was also performed in 16 of the 23 speleologists at two caves deprived of natural lightning. Two organic filters (450 nm and 550 nm) were used to compare visual function with and without filters. The mean age of the speleologists was 40.65 (± 10.93) years. We detected 26.1% participants with visual impairment of which refractive error (17.4%) was the major cause. In the cave environment the majority of the speleologists used a head flashlight with a mean illuminance of 451.0 ± 305.7 lux. Binocular visual acuity (BVA) was -0.05 ± 0.15 LogMAR (20/18). BVA for distance without filter was not statistically different from BVA with 550 nm or 450 nm filters (p = 0.093). Significant improved contrast sensitivity was observed with 450 nm filters for 6 cpd (p = 0.034) and 18 cpd (p = 0.026) spatial frequencies. There were no signs and symptoms of visual pathologies related to cave exposure. Illuminance levels were adequate to the majority of the activities performed. The enhancement in contrast sensitivity with filters could potentially improve tasks related with the activities performed in the cave.
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.
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Dissertação para obtenção do Grau de Doutor em Engenharia Mecânica
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É apresentado um estudo de Ascomycetes (XYLARIACEAE) nos Estados do Amazonas e de Mato Grosso (norte), onde foram registrados 9 gêneros, totalizando 31 espécies: Batistia annulipes Cif., Camillea bacillum(Mont., C. bilabiata Speg., C. cyclops (Mont.) Berk. & Curt., C. labellum Mont., C. leprieurii Mont., Daldinia concentrica (Bolt.) Ces. & de Not., D. eschscholzii (Ehr.) Rehm., D. gollani Henn., Hypoxylon nummularium Bull. ex Fr, Hypoxylon sp., Kretzschmaria cetrarioides(Welw. & Curr.) Sacc., K. clavus (Fr.) Sacc., K. heliscus (Mont.) Massee, K. microspora Henn., Phylacia globosa Lév., P. poculiformis(Mont., P. surinamensis (Berk. & Curt.) Dennis, P. turbinata (Berk.) Dennis, Rhopalostroma sphaerocephalum (Petch.) D. Hwksw., Thammomyces dendroidea Cooke & Massee, T. rastratus Mont., Xylaria dealbata Berk. & Curt., X feejeensis (Berk.) Fr., X. furcata Fr., X . ianthino-velutina (Mont.) Fr., X. juruensis P. Henn., X. begeliana (Lév.) FA., X. microceras(Mont.) Fr., X. polymorpha (Pers. ex Fr. ) Grev., X. scruposa (Fr) Fr., X. telfairii (Berk.) Fr. Xylaria sp.Foi elaborada uma chave para identificação dos gêneros e respectivas espécies, sendo que para cada taxon são dadas as sinonímias e algumas ilustrações dos espécimes examinados.
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სოფელ რუისპირში (თელავის რაიონი) ჩატარებული მიწისპირა ოზონის კონცენტრაციის (მოკ) გაზომვების დიდი სტატისტიკური მასალის საფუძველზე გამოკვლეულ იქნა მოკ-ის ცვალებადობის ხასიათი კახეთში მიმდინარე ელჭექიან და სეტყვა-ელჭექიან დღეებში.
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Electromagnetic compatibility, lightning, crosstalk surge voltages, Monte Carlo simulation, accident initiator