Diagnostic performance of visual screening tests in the elderly

This study aimed to determine and evaluate the diagnostic accuracy of visual screening tests for detecting vision loss in elderly. This study is defined as study of diagnostic performance. The diagnostic accuracy of 5 visual tests -near convergence point, near accommodation point, stereopsis, contrast sensibility and amsler grid—was evaluated by means of the ROC method (receiver operating characteristics curves), sensitivity, specificity, positive and negative likelihood ratios (LR+/LR−). Visual acuity was used as the reference standard. A sample of 44 elderly aged 76.7 years (±9.32), who were institutionalized, was collected. The curves of contrast sensitivity and stereopsis are the most accurate (area under the curves were 0.814−p = 0.001, C.I.95%[0.653;0.975]— and 0.713−p = 0.027, C.I.95%[0,540;0,887], respectively). The scores with the best diagnostic validity for the stereopsis test were 0.605 (sensitivity 0.87, specificity 0.54; LR+ 1.89, LR−0.24) and 0.610 (sensitivity 0.81, specificity 0.54; LR+1.75, LR−0.36). The scores with higher diagnostic validity for the contrast sensibility test were 0.530 (sensitivity 0.94, specificity 0.69; LR+ 3.04, LR−0.09). The contrast sensitivity and stereopsis test's proved to be clinically useful in detecting vision loss in the elderly.

Diagnostic performance of visual screening tests in the elderly

The aging of Portuguese population is characterized by an increase of individuals aged older than 65 years. Preventable visual loss in older persons is an important public health problem. Tests used for vision screening should have a high degree of diagnostic validity confirmed by means of clinical trials. The primary aim of a screening program is the early detection of visual diseases. Between 20% and 50% of older people in the UK have undetected reduced vision and in most cases is correctable. Elderly patients do not receive a systematic eye examination unless a problem arises with their glasses or suspicion vision loss. This study aimed to determine and evaluate the diagnostic accuracy of visual screening tests for detecting vision loss in elderly. Furthermore, it pretends to define the ability to find the subjects affected with vision loss as positive and the subjects not affected with the same disease as negative. The ideal vision screening method should have high sensitivity and specificity for early detection of risk factors. It should be also low cost and easy to implement in all geographic and socioeconomic regions. Sensitivity is the ability of an examination to identify the presence of a given disease and specificity is the ability of the examination to identify the absence of a given disease. It was not an aim of this study to detect abnormalities that affect visual acuity. The aim of this study was to find out what´s the best test for the identification of any vision loss.

Environmental life cycle assessment of concrete made with fine recycled concrete aggregates

The majority of worldwide structures use concrete as its main material. This happens because concrete is economically feasible, due to its undemanding production technology and case Of use. However, it is widely recognized that concrete production has a strong environmental impact in the planet. Natural aggregates use is one of the most important problems of concrete production nowadays, since they are obtained from limited, and in some countries scarce, resources. In Portugal, although there are enough stone quarries to cover coarse aggregates needs for several more years, Supplies of fine aggregates are becoming scarcer, especially in the northern part of the country. On the other hand, as concrete structures' life cycle comes to an end, an urgent need emerges to establish technically and economically viable solutions for demolition debris, other than for use as road base and quarry fill. This paper presents a partial life cycle assessment (LCA) of concrete made with fine recycled concrete aggregates performed with EcoConcrete tool. EcoConcrete is a tailor-made, interactive, learning and communications tool promoted by the Joint Project Group (JPG) on the LCA of concrete, to qualify and quantify the overall environment impact of concrete products. It consists of an interactive Excel-spreadsheet in which several environmental inputs (material quantities, distances from origin to production Site, production processes) and outputs (material, energy, emissions to air, water, soil or waste) are collected in a life cycle inventory, and are then processed to determine the environmental impact (assessment) of the analysed concrete, in terms of ozone layer depletion, smog or "greenhouse" effect.

Sistema de apoio à decisão para a classificação de risco em projectos de tecnologias de informação

O trabalho que a seguir se apresenta tem como objectivo descrever a criação de um modelo que sirva de suporte a um sistema de apoio à decisão sobre o risco inerente à execução de projectos na área das Tecnologias de Informação (TI) recorrendo a técnicas de mineração de dados. Durante o ciclo de vida de um projecto, existem inúmeros factores que contribuem para o seu sucesso ou insucesso. A responsabilidade de monitorizar, antever e mitigar esses factores recai sobre o Gestor de Projecto. A gestão de projectos é uma tarefa difícil e dispendiosa, consome muitos recursos, depende de numerosas variáveis e, muitas vezes, até da própria experiência do Gestor de Projecto. Ao ser confrontado com as previsões de duração e de esforço para a execução de uma determinada tarefa, o Gestor de Projecto, exceptuando a sua percepção e intuição pessoal, não tem um modo objectivo de medir a plausibilidade dos valores que lhe são apresentados pelo eventual executor da tarefa. As referidas previsões são fundamentais para a organização, pois sobre elas são tomadas as decisões de planeamento global estratégico corporativo, de execução, de adiamento, de cancelamento, de adjudicação, de renegociação de âmbito, de adjudicação externa, entre outros. Esta propensão para o desvio, quando detectada numa fase inicial, pode ajudar a gerir melhor o risco associado à Gestão de Projectos. O sucesso de cada projecto terminado foi qualificado tendo em conta a ponderação de três factores: o desvio ao orçamentado, o desvio ao planeado e o desvio ao especificado. Analisando os projectos decorridos, e correlacionando alguns dos seus atributos com o seu grau de sucesso o modelo classifica, qualitativamente, um novo projecto quanto ao seu risco. Neste contexto o risco representa o grau de afastamento do projecto ao sucesso. Recorrendo a algoritmos de mineração de dados, tais como, árvores de classificação e redes neuronais, descreve-se o desenvolvimento de um modelo que suporta um sistema de apoio à decisão baseado na classificação de novos projectos. Os modelos são o resultado de um extensivo conjunto de testes de validação onde se procuram e refinam os indicadores que melhor caracterizam os atributos de um projecto e que mais influenciam o risco. Como suporte tecnológico para o desenvolvimento e teste foi utilizada a ferramenta Weka 3. Uma boa utilização do modelo proposto possibilitará a criação de planos de contingência mais detalhados e uma gestão mais próxima para projectos que apresentem uma maior propensão para o risco. Assim, o resultado final pretende constituir mais uma ferramenta à disposição do Gestor de Projecto.

Desenvolvimento do sistema de tracção de um veículo eléctrico ecológico com travagem regenerativa

Nesta dissertação descreve-se uma metodologia de dimensionamento do sistema de tracção para equipar um veículo eléctrico ecológico (VEECO) com inclusão de um sistema de travagem regenerativa. Apresenta-se uma perspectiva geral de diversas topologias de sistemas de tracção utilizadas nos veículos eléctricos e realiza-se a sua comparação através do estudo e análise dos acionamentos electromecânicos que podem ser utilizados nesses sistemas de tracção eléctrica. Utilizando ferramentas de simulação numérica, estuda-se o modelo matemático de um veículo eléctrico com travagem regenerativa. A partir deste modelo matemático é adoptado uma possível configuração para o seu sistema de tracção eléctrica e são obtidas características teóricas de desempenho do veículo eléctrico, através da análise de testes padrão ao veículo. Em banco de ensaios, constrói-se um sistema de tracção eléctrica que permite a validação experimental do modelo matemático do veículo eléctrico. Para a construção deste banco de ensaios foram concebidos os sistemas de tracção eléctrica, de carga mecânica e de controlo e monitorização do banco de ensaios. A validação experimental realiza-se através dos mesmos testes padrão ao veículo eléctrico, como o teste NEDC (New European Driving Cycle), o teste de aceleração entre 0 e 100km/h e o teste de gradeabilidade. Desenvolve-se o dimensionamento do sistema de tracção eléctrica a equipar o VEECO, através da componente de modelação paramétrica do modelo matemático do veículo eléctrico. Com esta metodologia é adoptado um conjunto de variáveis paramétricas relacionadas com os elementos que constituem o sistema de tracção eléctrica do VEECO. Estuda-se a influência destas variáveis paramétricas nas características de desempenho pretendidas para o VEECO. Como resultado da análise de modelação paramétrica é apresentada uma solução para o sistema de tracção eléctrica do VEECO que cumpre a execução do NEDC, apresenta um tempo de aceleração entre 0 e 100km/h inferior a 10 segundos, supera uma gradeabilidade de 10% e uma autonomia de 200 km. O sistema de tracção do VEECO também permite realizar a travagem regenerativa com rendimento até 33%. Possui controlo de tracção e anti bloqueio da roda motora, através de uma unidade de controlo que permite reduzir a potência transmitida ao veio, quando a velocidade da roda de tracção difere do valor de referência da velocidade do veículo. Os conhecimentos adquiridos através do processo de investigação e desenvolvimento, para a realização da presente dissertação permitem apresentar perspectivas de desenvolvimento futuro com aplicação nos sistemas de tracção de veículos eléctricos rodoviários.

New Steel Alloys for the Design of Heat Recovery Steam Generator Components of Combined Cycle Gas Plants

Demand for power is growing every day, mainly due to emerging economies in countries such as China, Russia, India, and Brazil. During the last 50 years steam pressure and temperature in power plants have been continuously raised to improve thermal efficiency. Recent efforts to improve efficiency leads to the development of a new generation of heat recovery steam generator, where the Benson once-through technology is applied to improve the thermal efficiency. The main purpose of this paper is to analyze the mechanical behavior of a high pressure superheater manifold by applying finite element modeling and a finite element analysis with the objective of analyzing stress propagation, leading to the study of damage mechanism, e.g., uniaxial fatigue, uniaxial creep for life prediction. The objective of this paper is also to analyze the mechanical properties of the new high temperature resistant materials in the market such as 2Cr Bainitic steels (T/P23 and T/P24) and also the 9-12Cr Martensitic steels (T/P91, T/P92, E911, and P/T122). For this study the design rules for construction of power boilers to define the geometry of the HPSH manifold were applied.

Tubulin cofactor A gene silencing in mammalian cells induces changes in microtubule cytoskeleton, cell cycle arrest and cell death

Microtubules are polymers of alpha/beta-tubulin participating in essential cell functions. A multistep process involving distinct molecular chaperones and cofactors produces new tubulin heterodimers competent to polymerise. In vitro cofactor A (TBCA) interacts with beta-tubulin in a quasi-native state behaving as a molecular chaperone. We have used siRNA to silence TBCA expression in HeLa and MCF-7 mammalian cell lines. TBCA is essential for cell viability and its knockdown produces a decrease in the amount of soluble tubulin, modifications in microtubules and G1 cell cycle arrest. In MCF-7 cells, cell death was preceded by a change in cell shape resembling differentiation.

Prática de ensino supervisionado no 1.º e 2.º ciclo do ensino básico: a influência da planificação no desenvolvimento da escrita de textos

Relatório Final de Estágio apresentado à Escola Superior de Educação de Lisboa para obtenção do grau de mestre em Ensino do 1.º e do 2.º Ciclo do Ensino Básico

Layered smart grid architecture approach and field tests by ZigBee technology

This paper presents a layered Smart Grid architecture enhancing security and reliability, having the ability to act in order to maintain and correct infrastructure components without affecting the client service. The architecture presented is based in the core of well design software engineering, standing upon standards developed over the years. The layered Smart Grid offers a base tool to ease new standards and energy policies implementation. The ZigBee technology implementation test methodology for the Smart Grid is presented, and provides field tests using ZigBee technology to control the new Smart Grid architecture approach. (C) 2014 Elsevier Ltd. All rights reserved.

Is it possible to remove polymeric nanoparticles from aqueous paints during the activated sludge treatment?

The market for emulsion polymers (latexes) is large and growing at the expense of other manufacturing processes that emit higher amounts of volatile organic solvents. The paint industry is not an exception and solvent-borne paints have been gradually substituted by aqueous paints. In their life-cycle, much of the aqueous paint used for architectural or decorative purposes will eventually be discharged into wastewater treatment facilities, where its polymeric nanoparticles (mainly acrylic and styrene-acrylic) can work as xenobiotics to the microbial communities present in activated sludge. It is well established that these materials are biocompatible at macroscopic scale. But is their behaviour the same at nanoscale? What happens to the polymeric nanoparticles during the activated sludge process? Do nanoparticles agregate and are discharged together with the sludge or remain in emulsion? How do microorganisms interact with these nanoparticles? Are nanoparticles degradated by them? Are they adsorbed? Are these nanoparticles toxic to the microbial community? To study the influence of these xenobiotics in the activated sludge process, an emulsion of cross-linked poly(butyl methacrylate) nanoparticles of ca. 50 nm diameter was produced and used as model compound. Activated sludge from a wastewater treatment plant was tested by the OCDE’s respiration inhibition test using several concentrations of PBMA nanoparticles. Particle aggregation was followed by Dynamic Light Scattering and microorganism surfaces were observed by Atomic Force Microscopy. Using sequential batch reactors (SBRs) and continuous reactors, both inoculated with activated sludge, the consumption of carbon, ammonia, nitrite and nitrate was monitored and compared, in the presence and absence of nanoparticles. No particles were detected in all treated waters by Dynamic Light Scattering. This can either mean that microorganisms can efficiently remove all polymer nanoparticles or that nanoparticles tend to aggregate and be naturally removed by precipitation. Nevertheless respiration inhibition tests demonstrated that microorganisms consume more oxygen in the presence of nanoparticles, which suggests a stress situation. It was also observed a slight decrease in the efficiency of nitrification in the presence of nanoparticles. AFM images showed that while the morphology of some organisms remained the same both in the presence and absence of nanoparticles, others assumed a rough surface with hilly like shapes of ca. 50 nm when exposed to nanoparticles. Nanoparticles are thus likely to be either incorporated or adsorbed at the surface of some organisms, increasing the overall respiration rate and decreasing nitrification efficiency. Thus, despite its biocompatibility at macroscopic scale, PBMA is likely to be no longer innocuous at nanoscale.

Semi-destructive in situ tests as support to the assessment of a conservation process

This paper refers to the assessment on site by semi-destructive testing (SDT) methods of the consolidation efficiency of a conservation process developed by Henriques (2011) for structural and non-structural pine wood elements in service. This study was applied on scots pine wood (Pinus sylvestris L.) degraded by fungi after treatment with a biocidal product followed by consolidation with a polymeric product. This solution avoids substitutions of wood moderately degraded by fungi, improving its physical and mechanical characteristics. The consolidation efficiency was assessed on site by methods of drill resistance and penetration resistance. The SDT methods used showed good sensitivity to the conservation process and could evaluate their effectiveness. (C) 2015 Elsevier Ltd. All rights reserved.

On a self-start Darrieus wind turbine: blade design and field tests

This paper is about a design of an urban area Darrieus VAWT, having self-start ability due to an innovative profile design named EN0005, avoiding the need of extra components or external electricity feed-in. An approach is presented to study the ability of a blade profile to offer self-start ability. Methodologies applied for the blade body and for profile development are reported. Field tests and main conclusions are presented to persuade for the arrangement of this design. (C) 2015 Elsevier Ltd. All rights reserved.

Syngas production by water electrolysis: preliminary tests on methane production

Master Thesis to obtain the Master degree in Chemical Engineering - Branch Chemical Processes