1,112 research outputs found

    Monitorização da qualidade da energia elétrica

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    A monitorização da Qualidade da Energia Elétrica é uma mais-valia para os responsáveis pelas instalações elétricas, permitindo a otimização dos perfis de consumo e a identificação e prevenção de problemas.Fundação para a Ciência e a Tecnologia (FCT

    Aortic valve endocarditis by a rare infectious agent in a patient with a rare congenital mitral valve abnormality

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    © The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact [email protected] description: A 66-year-old woman with a past medical history of high blood pressure, Type 2 diabetes mellitus and no clinical evidence of immunocompromise, presented to the emergency room with fever and acute pulmonary oedema. The patient had presented low-grade fever and anorexia in the previous 3 weeks.info:eu-repo/semantics/publishedVersio

    A Novel Robotic Manipulator Concept for Managing the Winding and Extraction of Yarn Coils

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    Wire rope manufacturing is an old industry that maintains its place in the market due to the need for products with specific characteristics in different sectors. The necessity for modernization and performance improvement in this industry, where there is still a high amount of labor dedicated to internal logistics operations, led to the development of a new technology method, to overcome uncertainties related to human behaviour and fatigue. The removal of successive yarn coils from a twisting and winding machine, as well as cutting the yarn and connecting the other end to the shaft in order to proceed with the process, constitutes the main problem. As such, a mobile automatic system was created for this process, due to its automation potential, with a project considering the design of a 3D model. This novel robotic manipulator increased the useful production time and decreased the winding coil removal cycle time, resulting in a more competitive, fully automated product with the same quality. This system has led to better productivity and reliability of the manufacturing process, eliminating manual labor and its cost, as in previously developed works in other industriesThe authors want to thank Jorge Seabra and Carlos Fernandes from CETRIB/INEGI/LAETA due their continuous support.info:eu-repo/semantics/publishedVersio

    Mathematical modeling of styrene/divinylbenzene copolymerization comprising diffusional effects and cyclization kinetics

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    Mathematical Modeling of Styrene/Divinylbenzene Copolymerization Comprising Diffusional Effects and Cyclization KineticsEuropean Commission - Marie Curie Initial Training Networ

    Stress acts cumulatively to precipitate Alzheimer’s disease-like tau pathology and cognitive deficits

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    Stressful life experiences are likely tiological factors in sporadic forms of Alzheimer’s disease (AD). Many AD patients hypersecrete glucocorticoids (GCs), and their GC levels correlate with the rate of cognitive impairment and extent of neuronal atrophy. Severity of cognitive deficits in AD correlates strongly with levels of perphosphorylated forms of the cytoskeletal protein TAU, an essential mediator of the actions of amyloid Beta (ABeta ), another molecule with a key pathogenic role in AD. Our objective was to investigate the sequential interrelationships between these various pathogenic elements, in particular with respect to the mechanisms through which stress might precipitate cognitive decline. We thus examined whether stress, through the mediation of GCs, influences TAU hyperphosphorylation, a critical and early event in the cascade of processes leading to AD pathology. Results from healthy, wild-type, middle-aged rats show that chronic stress and GC induce abnormal hyperphosphorylation of TAU in the hippocampus and prefrontal cortex (PFC), with contemporaneous impairments of hippocampus- and PFC-dependent behaviors. Exogenous GC potentiated the ability of centrally infused ABeta to induce hyperphosphorylation of TAU epitopes associated with AD and cytoplasmic accumulation of TAU, while previous exposure to stress aggravated the biochemical and behavioral effects of GC in ABeta-infused animals. Thus, lifetime stress/GC exposure may have a cumulative impact on the onset and progress of AD pathology, with TAU hyperphosphorylation serving to transduce the negative effects of stress and GC on cognition.Marie Curie Training FellowshipsEU CRESCENDO Consortium contract FP6-018652University College, London.Max Planck Society and European Union (EU) German-Portuguese Luso-Alemas Program and the EU CRESCENDO Consortium (Contract FP6-018652).German-Portuguese Luso-Alemas Progra

    Efeitos implícitos da pertença e identificação grupais na discriminação social

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    Utilizando uma metodologia não-obstrusiva, testámos a hipótese de que a associação entre estímulos visuaisnão salientes e a pertença grupal dos indivíduos pode interferir na escolha de uma equipa de trabalho sem que estes se apercebam dessa influência. As participantes (66 estudantes dos cursos de Psicologia e de Serviço Social) foram acolhidas por uma Psicóloga vs. Trabalhadora Social após o que deveriam escolher entre duas equipas, fisicamente semelhante vs. Diferente da pessoa que as recebeu, para a continuação do mesmo estudo. Os resultados mostraram que as participantes que foram acolhidas pelo membro do exogrupo escolheram mais a equipa diferente do que as participantes acolhidas pelo membro do endogrupo sendo este efeito mediado pela identificação ao endogrupo. Os resultados são discutidos à luz de investigação anterior utilizando medidas implícitas de discriminação social

    Predictive control of a current-source inverter for solar photovoltaic grid interface

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    Solar photovoltaic systems are an increasing option for electricity production, since they produce electrical energy from a clean renewable energy resource, and over the years, as a result of the research, their efficiency has been increasing. For the interface between the dc photovoltaic solar array and the ac electrical grid is necessary the use of an inverter (dc-ac converter), which should be optimized to extract the maximum power from the photovoltaic solar array. In this paper is presented a solution based on a current-source inverter (CSI) using continuous control set model predictive control (CCS-MPC). All the power circuits and respective control systems are described in detail along the paper and were tested and validated performing computer simulations. The paper shows the simulation results and are drawn several conclusions.FCT - Fundação para a Ciência e Tecnologia within scope of the project: PEst- UID/CEC/00319/201

    Direct oral anticoagulants versus vitamin K antagonists in patients with antiphospholipid syndrome: systematic review and meta-analysis

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    © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. http://creativecommons.org/licenses/by-nc/4.0/This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.Background: Despite vitamin K antagonists (VKA) being the gold standard in the prevention of thromboembolic events in antiphospholipid syndrome (APS), non-vitamin K antagonists oral anticoagulants/direct oral anticoagulants (DOACs) have been used off-label. Objective: We aimed to perform a systematic review comparing DOACs to VKA regarding prevention of thromboembolic events, occurrence of bleeding events and mortality in patients with APS. Methods: An electronic database search was performed through MEDLINE, CENTRAL and Web of Science. After data extraction, we pooled the results using risk ratio (RR) and 95% CI. Heterogeneity was assessed using the I². The outcomes considered were all thromboembolic events as primary, and major bleeding, all bleeding events and mortality as secondary. Evidence confidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation methodology. Results: We included 7 studies and a total of 835 patients for analyses. Thromboembolic events were significantly increased in DOACs arm, compared with VKA-RR 1.69, 95% CI 1.09 to 2.62, I²-24%, n=719, 6 studies. In studies using exclusively rivaroxaban, which was the most representative drug in all included studies, the thromboembolic risk was increased threefold (RR 3.36, 95% CI 1.53 to 7.37). The risks of major bleeding, all bleeding events and mortality were not significantly different from control arm. The grade of certainty of our results is very low. Conclusions: Current evidence suggests DOACs use, particularly rivaroxaban, among patients with APS, is less effective than VKA since it is associated with 69% increased risk of thromboembolic events.info:eu-repo/semantics/publishedVersio

    A comprehensive comparison of voltage and current control techniques for three-phase VSI converters

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    Converting electrical energy from direct current to alternate current, or vice versa, is one of the most frequently performed tasks in today’s electrical systems. The Voltage Source Inverter (VSI) is the most widely used topology to accomplish this task. This paper compares the performance of three control algorithms for voltage source inverter (VSI) with PI, PR and MP control algorithms were applied for voltage control and current control. For voltage control the VSI synthesizes the sinusoidal voltage system for an islanded application. In current control the VSI injects energy into the power grid by synthesizing sinusoidal currents. A general comparison is made of the performance of the three control algorithms under the presented conditions, helping to choose the control algorithm to use in a given application.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project QUALITY4POWER PTDC/EEI-EEE/28813/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Mr. Luis A. M. Barros is supported by the doctoral scholarship PD/BD/143006/2018 granted by the Portuguese FCT foundation

    Comparison of 5 acute pulmonary embolism mortality risk scores in patients with COVID-19

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    © The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Objective: Pulmonary embolism (PE) is a common complication of SARS-CoV-2 infection. We aimed to explore the short-term outcomes among patients with acute PE and COVID-19 and to further determine and compare the performance of the different prognostic scores (PESI, sPESI, BOVA, FAST and ESC scores) for risk-stratification in this scenario. Methods: Retrospective single-centre study of 85 patients with SARS-CoV-2 infection and PE admitted to the Emergency Department (ED). The diagnostic accuracy of each above-mentioned prognostic score was calculated post hoc, and their discriminative power was evaluated through an AUC curve. Results: Among the 85 patients, all-cause death occurred within 7 days for 6 patients (7.1%) and within 30 days for 14 patients (16.5%). Despite being older and having a higher percentage of altered mental status on presentation, non-survivors patients did not differ from survivors regarding comorbidities, traditional risk factors for venous thromboembolism and signs and symptoms at the ED presentation.Each risk stratification tool had modest discriminative power for 7-day mortality (AUC range, 0.601-0.730) with slightly lower discrimination for 30-day mortality (AUC range, 0.543-0.638). The pair-wise comparison of ROC curves showed that PESI had better predictive value for short-term mortality than ESC score (z test = 3.92, p = 0.001) and sPESI (z test = 2.43, p = 0.015); there is no significant difference between PESI and BOVA score (z test = 1.05, p = 0.295) and FAST score (z test = 0.986, p = 0.324). Conclusion: The most common risk-stratification tools for PE had modest discriminative power to predict short-term mortality in patients with acute PE and COVID-19.info:eu-repo/semantics/publishedVersio
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