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Now showing items 1 - 16 of 91

  • Os Proprietários Florestaisby Fernando Oliveira Baptista; Ricardo Terra Santos

    Review by: Amélia Branco Dias  

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  • Os Proprietários Florestaisby Fernando Oliveira Baptista; Ricardo Terra Santos

    Review by: Amélia Branco Dias  

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  • Vehicle Driver Monitoring through the Statistical Process Control

    Assuncao, Arthur   Aquino, Andre   Câmara de M. Santos, Ricardo   Guimaraes, Rodolfo   Oliveira, Ricardo  

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  • Seroprevalence of Hepatitis E Virus Antibodies in Portuguese Children

    Oliveira, Ricardo   Mesquita, Joao Rodrigo   Pereira, Sara   Abreu-Silva, Joana   Teixeira, Joana   Jose Nascimento, Maria Sao  

    Background: Hepatitis E virus (HEV) has become a growing public health concern in industrialized countries. Most of the HEV seroprevalence studies have focused on adult populations, and reports regarding HEV seroepidemiology among children are scarce in these countries. The aims of this work were to perform a nationwide seroprevalence study on HEV infection in Portuguese children and to compare the HEV seropositivity in this 2015 children cohort with results in sera performed 20 years earlier. Methods: Sera (N =3D 352) from children collected in 2015 from all regions of Portugal were screened for anti-HEV IgG and IgM using the commercial enzyme-linked immunosorbent assay recomWell HEV IgG/IgM (2015 version; Mikrogen, Neuried, Germany), and positive samples were retested by immunodot assay recomLine HEV IgG/IgM (2015 version; Mikrogen, Neuried, Germany). For the comparative assessment of HEV seropositivity of the 2 children cohorts, children's sera (N =3D 71) archived since 1995 were screened for anti-HEV IgG and results were compared with that of the 2015 cohort, matched by sex, age and region. Results: Anti-HEV antibodies were detected in 4 children giving an overall HEV seroprevalence in the 2015 cohort of 1.1%. A healthy 10-15-year-old female was found positive for anti-HEV IgM indicating a current or recent HEV infection. No statistically significant difference was observed in HEV seroprevalence regarding gender, age group and region of residence. Comparison of the HEV seropositivity of the 2 children cohorts showed a statistical significant decrease with time (P =3D 0.024). Conclusions: This is the first national study of HEV seroprevalence in Portuguese children and the first to demonstrate a decrease of anti-HEV antibodies in this age group over time.
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  • Morphological transition of Helicobacter pylori adapted to water

    Fernandes, Ricardo M.   Silva, Helder   Oliveira, Ricardo   Almeida, Carina   Azevedo, Nuno F.   Vieira, Maria J.  

    Aim: This study aims to investigate the morphological transition of Helicobacter pylori during adaptation to water. Materials & methods: Different strains were adapted to water. Changes regarding cultivability and cellular morphology were recorded. Expression of 11 genes involved in H. pylori morphological changes was evaluated by real-time PCR. Results: H. pylori presented increased cultivability in water after adaptation. The permanent loss of the spiral shape was observed, but no transition into coccoid form has occurred. Expression levels of genes involved in peptidoglycan assembly of H. pylori 26695 have shown significant changes between adapted and nonadapted strains. Conclusion: Adaption to water favors the culturable phenotype and the morphological transition to the rod shape, into a process that implicates the peptidoglycan turnover.
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  • Surgical approaches for bronchopleural fistula

    Dal Agnol, Guilherme   Vieira, Arthur   Oliveira, Ricardo   Ugalde Figueroa, Paula Antonia  

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  • Seroprevalence of Hepatitis E Virus Antibodies in Portuguese Children

    Oliveira, Ricardo   Mesquita, Jo?o Rodrigo   Pereira, Sara   Abreu-Silva, Joana   Teixeira, Joana   Nascimento, Maria S?o José  

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  • Bragg Gratings Inscription in Highly Birefringent Microstructured POFs

    Oliveira, Ricardo   Bilro, Lucia   Marques, Thiago H. R.   Napierala, Marek   Tenderenda, Tadeusz   Mergo, Pawel   Nasilowski, Tomasz   Cordeiro, Cristiano M. B.   Nogueira, Rogerio  

    We report for the first time, the fast inscription of high-quality Bragg gratings in highly birefringent microstructured polymer optical fibers by the phase mask method using 248-nm UV radiation. The fibers birefringence is created through a special design of the structure of holes through the fiber. A Bragg grating in these type of fibers allows the creation of two reflection peaks, where the peak separation is related to the phase birefringence.
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  • [INVITED] New advances in polymer fiber Bragg gratings

    Nogueira, Rogerio   Oliveira, Ricardo   Bilro, Lucia   Heidarialamdarloo, Jamshid  

    During the last years, fiber Bragg gratings (FBGs) written in polymer optical fibers (POFs) have been pointed as an interesting alternative to silica FBGs for applications in sensors and in optical access networks. In order to use such components in real applications, the manipulation of POFs, as well as the increase of quality in the production of FBGs has to be achieved. In this article some of the recent advances regarding these two aspects are reported and include recent developments to produce smooth POFs end face with high quality, benefiting the current splicing process and the inscription of high quality FBGs in a few seconds. Furthermore, additional characterizations to strain, temperature, pressure, and humidity are also shown. (C) 2015 Elsevier Ltd. All rights reserved.
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  • Bragg Gratings Inscription in Highly Birefringent Microstructured POFs

    Oliveira, Ricardo   Bilro, Lucia   Marques, Thiago H. R.   Napierala, Marek   Tenderenda, Tadeusz   Mergo, Pawel   Nasilowski, Tomasz   Cordeiro, Cristiano M. B.   Nogueira, Rogerio  

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  • Multiparameter POF Sensing Based on Multimode Interference and Fiber Bragg Grating

    Oliveira, Ricardo   Marques, Thiago H. R.   Bilro, Lucia   Nogueira, Rogerio   Cordeiro, Cristiano M. B.  

    We report the fabrication of a multimode interferometer (MMI), based on a multimode polymer optical fiber (POF), sandwiched between two single-mode silica fibers. The POF used in this work is a step-index fiber with core and cladding composed of a cycloolefin polymer (COP) and PMMA, respectively. The low moisture absorption of the COP material and the benefit of having an exposed core for refractive indexmeasurements in MMI devices lead us to perform an etching of the PMMAlayer. Additionally, we report the inscription of a Bragg grating in the COP core material of an etched single-mode-multimode-single-mode (SMS) structure. The two fiber structures were simultaneously characterized to strain, temperature, humidity, and refractive index. The ability to detect refractive index by using a POF-based SMS structure is reported for the first time in this paper. Additionally, the capability for dual parameter measurement was discussed using both FBG and SMS structures.
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  • Acquired Traumatic Arteriovenous Fistula of the Long Finger

    Oliveira, Ricardo   Costa, Joana   Monteiro, Diana   Silva, Alvaro  

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  • Multiparameter POF Sensing based on Multimode Interference and Fiber Bragg Grating

    Oliveira, Ricardo   Marques, Thiago H. R.   Bilro, Lucia   Nogueira, Rogerio   Cordeiro, Cristiano M. B.  

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  • Efficiency performance of the Algarve hotels using a revenue function

    Oliveira, Ricardo   Pedro, Maria Isabel   Marques, Rui Cunha  

    The tourism industry, particularly the hotel sector, is becoming increasingly competitive and dynamic as a result of the pressures of globalized supply and demand in a context of uncertainty. The aim of this study is to discuss the efficiency of hotel companies in the Algarve (Portugal), a tourist destination of excellence in southwest Europe. In particular, we intend to assess the efficiency of the hotels in terms of star rating (four and five-star hotels), their location (Windward and Leeward), owning or not golf courses and owning just a single hotel or more than one. This analysis will be based on the parametric method of stochastic frontier approach using a revenue function. We found relevant levels of inefficiency. The results also point out the important role of the operational environment, particularly the hotel location and the existence of golf facilities. Star rating and owning multiples hotels do not seem to be so relevant. (C) 2013 Elsevier Ltd. All rights reserved.
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  • Efficiency and its determinants in Portuguese hotels in the Algarve

    Oliveira, Ricardo   Pedro, Maria Isabel   Marques, Rui Cunha  

    This paper uses non-parametric techniques to investigate and compare the efficiency of Portuguese hotels in the Algarve, the comparison being made between those hotels possessing golf courses and those that do not. The Algarve is one of the more important tourism locations in Portugal and a popular destination for tourists from many countries and specifically attracts tourists seeking to play golf. By using data envelopment analysis (DEA) this study investigates the influence of star ratings, golf courses and location on hotel efficiency. Additionally the study uses the test devised by Carvalho and Marques that takes into account the equality of the entire efficiency distribution. We conclude that star rating is not a significant determinant of efficiency but location and the existence of golf courses may have some relevance. A major finding is that it is those hotels that do not possess golf courses that are the more efficient.
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  • Validation of a Cardiopulmonary Exercise Test Score in Heart Failure

    Myers, Jonathan   Oliveira, Ricardo   Dewey, Frederick   Arena, Ross   Guazzi, Marco   Chase, Paul   Bensimhon, Daniel   Peberdy, Mary Ann   Ashley, Euan   West, Erin   Cahalin, Lawrence P.   Forman, Daniel E.  

    Background-Cardiopulmonary exercise test (CPX) responses are strong predictors of outcomes in patients with heart failure. We recently developed a CPX score that integrated the additive prognostic information from CPX. The purpose of this study was to validate the score in a larger, independent sample of patients. Methods and Results-A total of 2625 patients with heart failure underwent CPX and were followed for cardiovascular (CV) mortality and major CV events (death, transplantation, left ventricular assist device implantation). Net reclassification improvement (NRI) for the score and each of its components were determined at 3 years. The VE/VCO2 slope was the strongest predictor of risk and was attributed a relative weight of 7, with weighted scores for abnormal heart rate recovery, oxygen uptake efficiency slope, end-tidal CO2 pressure, and peak VO2 having scores of 5, 3, 3, and 2, respectively. A summed score of >15 was associated with an annual mortality rate of 12.2% and a relative risk >9 for total events, whereas a score of <5 was associated with an annual mortality rate of 1.2%. The composite score was the most accurate predictor of CV events among all CPX responses considered (C indexes, 0.70 for CV mortality and 0.72 for the composite outcome). Each component of the score provided significant NRI compared with peak VO2 (category-free NRI, 0.61-0.77), and the score provided significant NRI above clinical risk factors for both CV events and mortality (NRI, 0.63 and 0.65 for CPX score compared with clinical variables alone). Conclusions-These results validate the application of a simple, integrated multivariable score based on readily available
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