Browsing by Author "Santos, Miguel"
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- Assessment of perioperative mortality risk in patients with infective endocarditis undergoing cardiac surgery: performance of the EuroSCORE I and II logistic modelsPublication . Madeira, Sérgio; Rodrigues, Ricardo; Tralhão, António; Santos, Miguel; Almeida, Carla; Marques, Marta; Ferreira, Jorge; Raposo, Luís; Neves, José; Mendes, MiguelOBJECTIVES: The European System for Cardiac Operative Risk Evaluation (EuroSCORE) has been established as a tool for assisting decision- making in surgical patients and as a benchmark for quality assessment. Infective endocarditis often equires surgical treatment and is associated with high mortality. This study was undertaken to (i) validate both versions of the EuroSCORE, the older logistic EuroSCORE I and the recently developed EuroSCORE II and to compare their performances; (ii) identify predictors other than those included in the EuroSCORE models that might further improve their performance. METHODS: We retrospectively studied 128 patients from a single-centre registry who underwent heart surgery for active infective endocarditis between January 2007 and November 2014. Binary logistic regression was used to find independent predictors of mortality and to create a new prediction model. Discrimination and calibration of models were assessed by receiver-operating characteristic curve analysis, calibration curves and the Hosmer–Lemeshow test. RESULTS: The observed perioperative mortality was 16.4% (n = 21). The median EuroSCORE I and EuroSCORE II were 13.9% interquartile range (IQ) (7.0–35.0) and 6.6% IQ (3.5–18.2), respectively. Discriminative power was numerically higher for EuroSCORE II {area under the curve (AUC) of 0.83 [95% confidence interval (CI), 0.75–0.91]} than for EuroSCORE I [0.75 (95% CI, 0.66–0.85), P = 0.09]. The Hosmer– Lemeshow test showed good calibration for EuroSCORE II (P = 0.08) but not for EuroSCORE I (P = 0.04). EuroSCORE I tended to overpredict and EuroSCORE II to under-predict mortality. Among the variables known to be associated with greater infective endocarditis severity, only prosthetic valve infective endocarditis remained an independent predictor of mortality [odds ratio (OR) 6.6; 95% CI, 1.1–39.5; P = 0.04]. The new model including the EuroSCORE II variables and variables known to be associated with greater infective endocarditis severity showed an AUC of 0.87 (95% CI, 0.79–0.94) and differed significantly from EuroSCORE I (P = 0.03) but not from EuroSCORE II (P = 0.4). CONCLUSIONS: Both EuroSCORE I and II satisfactorily stratify risk in active infective endocarditis; however, EuroSCORE II performed better in the overall comparison. Specific endocarditis features will increase model complexity without an unequivocal improvement in predictive ability.
- Climatização Geosolar em MouraPublication . Santos, Miguel; Duarte, RogérioNeste artigo faz-se a descrição de conceitos subjacentes ao sistema de climatização geosolar aplicado no novo edifício da Lógica, E.M. em Moura, incluindo-se fundamentação teórica, aspetos preditivos de funcionamento, descrição técnica, considerações quanto aos custos e sustentabilidade, e, enquadramento ao abrigo do SCE. Trata-se de um sistema de AVAC Carbono Zero, ideal para aplicação em várias latitudes, nomedamente as de Portugal Continental. Como principais conclusões deve referir-se que é possível obter uma solução deste tipo com um custo global da ordem de grandeza do de sistemas de AVAC de elevada qualidade o que significará que as poupanças dos custos com energia começam a ser sentidas desde o primeiro dia de utilização. Tornou-se ainda possível que um edifício de serviços que estaria naturalmente abrangido pelo RSECE, seja tratado ao nível do RCCTE.
- Fault location in an electrical energy distribution infrastructure with a wireless sensor networkPublication . Fortunato, Carlos; Casaca, Augusto; Grilo, António; Santos, MiguelThis article presents a detailed analysis of the applicability of wireless systems in the localization of faults in the energy distribution network. The hwardware and software architectures of the envised sensor solution will also be described and finally, the integration of this system into Smart Grids will be discussed in terms of automatic fault analysis. A pilot system has been tested in a subset of the Portuguese energy distribution infrastructure operated by EDP Energias de Portugal. It presents a new approach to a fault locator system for the power network. The purpose is to obtain faster and more reliable information about the disruptions in the power distribution network and their location. Furthermore, the wireless sensors allow remote detection of medium and low voltage (MV/LV) power transformer hotspots in order to identify emerging malfunction as well as detection of intrusion in the MV/LV power transformers.
- Fault location in an electrical energy distribution infrastructure with a wireless sensor networkPublication . Fortunato, Carlos; Casaca, Augusto; Grilo, António; Santos, MiguelThis paper presents a detailed analysis of the applicability of wireless systems in the localization of faults in the energy distribution network. The hardware and software architectures of the envisaged sensor solution will also be described and finally, the integration of this system into Smart Grids will be discussed in terms of automatic fault analysis. A pilot system has been tested in a subset of the Portuguese energy distribution infrastructure operated by EDP Energias de Portugal. It presents a new approach to a fault locator system for the power network. The purpose is to obtain faster and more reliable information about the disruptions in the power distribution network and their location. Furthermore, the wireless sensors allow remote detection of medium and low voltage (MV/LV) power transformer hotspots in order to identify emerging malfunction as well as detection of intrusion in the MV/LV power transformers.
- Impact of Natural Ventilation on the Thermal and Energy Performance of Buildings in a Mediterranean ClimatePublication . Rodrigues, A. Moret; Santos, Miguel; Gomes, M. Glória; Duarte, RogérioNatural ventilation plays an important role on the thermal and energy performance of a building. The present study aims to analyze the natural ventilation conditions of a dwelling in a Mediterranean climate and their impacts on the thermal and energy performance using an advanced building energy simulation tool. Several multi-zone simulations were carried out. In the summer, the simulations were performed under free-floating conditions, whereas in the winter they were carried out under controlled temperature conditions. In the summer, ventilation scenarios with windows opened during certain periods of time and with or without permanent openings in the facades were analyzed. The existence of permanent openings proved to be an important factor of temperature control by lowering the average indoor zone temperatures during the day. Cross-ventilation also showed to be e ective. In the winter, we simulated the existence or absence of permanent openings for room ventilation and their surface area. The results showed that the stack e ect plays an important role in the ventilation and that in general it outperforms the wind e ect. Sizing permanent openings according to the standard guidelines proved to be adequate in providing the expected ventilation rates on an average basis.
- Outsourcing nos serviços públicosPublication . Santos, MiguelNo dia-a-dia das organizações tomam-se decisões e realizam-se tarefas de modo a cumprirem os seus objectivos. Estas gerem recursos cada vez mais escassos, deste modo é necessário que haja uma boa empregabilidade dos mesmos. É fundamental que as organizações evoluam e adoptem mecanismos que lhes permitam facilitar processos e gerir recursos de forma económica, obtendo o máximo de eficácia e eficiência. Esta investigação foca-se no outsourcing de serviços, especial no catering. Efectua-se uma análise comparativa dos valores referentes ao serviço de alimentação na Sede da Academia Militar, entre a Manutenção Militar e duas empresas de catering. Este trabalho estrutura-se em três partes fundamentais. Primeiramente efectua-se o enquadramento teórico em que se aborda o conceito do outsourcing e a sua aplicabilidade na Academia Militar. Posteriormente, expõe-se o trabalho de campo, com uma análise e apresentação dos resultados obtidos durante as entrevistas, questionários e estudo de caso. Constat a-se que as pessoas se encontram satisfeitas com o serviço de catering na unidade analisada, tendo em conta as áreas relevantes apontadas pelos entrevistados. Por fim, tece-se as considerações finais e linhas futuras de investigação, onde se verifica que o catering é uma ferramenta vantajosa para a Academia Militar. Este pode ser a resposta para alguns dos actuais problemas, pois permite uma redução de custos e um elevado grau de satisfação.