A reliability-based measure of robustness for concrete structures subjected to corrosion

This work is a contribution to the definition and assessment of structural robustness. Special emphasis is given to reliability of reinforced concrete structures under corrosion of longitudinal reinforcement. On this communication several authors’ proposals in order to define and measure structural robustness are analyzed and discussed. The probabilistic based robustness index is defined, considering the reliability index decreasing for all possible damage levels. Damage is considered as the corrosion level of the longitudinal reinforcement in terms of rebar weight loss. Damage produces changes in both cross sectional area of rebar and bond strength. The proposed methodology is illustrated by means of an application example. In order to consider the impact of reinforcement corrosion on failure probability growth, an advanced methodology based on the strong discontinuities approach and an isotropic continuum damage model for concrete is adopted. The methodology consist on a two-step analysis: on the first step an analysis of the cross section is performed in order to capture phenomena such as expansion of the reinforcement due to the corrosion products accumulation and damage and cracking in the reinforcement surrounding concrete; on the second step a 2D deteriorated structural model is built with the results obtained on the first step of the analysis. The referred methodology combined with a Monte Carlo simulation is then used to compute the failure probability and the reliability index of the structure for different corrosion levels. Finally, structural robustness is assessed using the proposed probabilistic index.

Development and validation of a risk model for prediction of hazardous alcohol consumption in general practice attendees : the PredictAL study

Background: Little is known about the risk of progression to hazardous alcohol use in people currently drinking at safe limits. We aimed to develop a prediction model (predictAL) for the development of hazardous drinking in safe drinkers. Methods: A prospective cohort study of adult general practice attendees in six European countries and Chile followed up over 6 months. We recruited 10,045 attendees between April 2003 to February 2005. 6193 European and 2462 Chilean attendees recorded AUDIT scores below 8 in men and 5 in women at recruitment and were used in modelling risk. 38 risk factors were measured to construct a risk model for the development of hazardous drinking using stepwise logistic regression. The model was corrected for over fitting and tested in an external population. The main outcome was hazardous drinking defined by an AUDIT score >= 8 in men and >= 5 in women. Results: 69.0% of attendees were recruited, of whom 89.5% participated again after six months. The risk factors in the final predictAL model were sex, age, country, baseline AUDIT score, panic syndrome and lifetime alcohol problem. The predictAL model's average c-index across all six European countries was 0.839 (95% CI 0.805, 0.873). The Hedge's g effect size for the difference in log odds of predicted probability between safe drinkers in Europe who subsequently developed hazardous alcohol use and those who did not was 1.38 (95% CI 1.25, 1.51). External validation of the algorithm in Chilean safe drinkers resulted in a c-index of 0.781 (95% CI 0.717, 0.846) and Hedge's g of 0.68 (95% CI 0.57, 0.78). Conclusions: The predictAL risk model for development of hazardous consumption in safe drinkers compares favourably with risk algorithms for disorders in other medical settings and can be a useful first step in prevention of alcohol misuse.

Stochastic simulation of the morphology of fluvial sand channels reservoirs

Dissertação para obtenção do Grau de Mestre em Engenharia Geológica (Georrecursos)

Integrating wind generation in the distribution network

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Energias Renováveis – Conversão Eléctrica e Utilização Sustentáveis

Hydrologic modeling and uncertainty analysis of an ungauged watershed using mapwindow-swat

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies

Algorithm for the Parkinson’s disease behavioural models characterization using a biosensor

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

A família cuidadora perante a dependência do seu familiar idoso

RESUMO: O envelhecimento demográfico tem vindo a acentuar-se nas últimas décadas. É expectável um aumento mais acentuado no número de pessoas com mais de 80 anos, o que importará maiores custos médicos, mais suporte familiar e comunitário, maior probabilidade de cuidados de longa duração devido à prevalência de doenças crónicas. Conduzindo a uma maior procura de apoios formais e informais. A preocupação com aqueles que atingem idades avançadas tem vindo a suscitar inquietação face à urgência de necessidades de suporte, sentidas por familiares, amigos e vizinhos. A questão central que orientou este estudo diz respeito aos familiares cuidadores ou gestores de cuidados do seu familiar idoso dependente e ao idoso dependente. Procurei identificar quais as dificuldades sentidas e as estratégias desenvolvidas pela família cuidadora ou gestora dos cuidados prestados ao idoso dependente, descrever e caracterizar a dependência destes idosos. É um estudo transversal, exploratório, descritivo, de abordagem quantitativa e qualitativa. Apliquei um questionário a 25 familiares cuidadores ou gestores dos cuidados a idosos dependentes, internados nos serviços de medicina e cirurgia de um hospital privado, Hospital CUF Descobertas, possuindo previamente alguma dependência. Dos dados obtidos ressalta que as principais dificuldades sentidas pelos familiares cuidadores ou gestores dos cuidados são essencialmente na gestão do tempo e a saúde do cuidador. Estratégias mais desenvolvidas foram o recurso a empregada doméstica e a outros familiares. Posso Concluir que há uma tendência preferencial por parte da família, na complementaridade de apoios informais e formais para prestar os cuidados ao idoso dependente no seio da família.------------ ABSTRACT: Demographic aging has risen progressively over the past decades. The number of people over the age of 80 years old is expected to increase considerably and surely result in the rise of medical costs, the growing need for additional community and family support, higher probability of long-term medical care due to the increased risk of chronic disease and the seeking of help regarding formal and informal support. The concern with persons that attain advanced age has brought about a certain degree of uneasiness regarding the urgency of the need of support systems felt by family members, friends, neighbours. The main topic that has steered this study pertains to the family caregivers or the care managers of dependant elderly relatives and dependant elderly persons. I endeavoured to identify encountered difficulties and the strategies undertaken by family caregivers or care managers in regard to the elderly dependant, to describe and characterize the nature of the dependency of these elderly persons. Furthermore, this study could be defined as being wide-reaching, exploratory and descriptive, by means of a qualitative and quantitative approach. I utilized a questionnaire that involved 25 family caregivers and care managers of dependant elderly (hospitalized in medical or surgery wards of private hospital, CUF Descobertas Hospital and suffering from some type of dependency). Conclusions: The main difficulties felt by family caregivers or care managers are primarily related to time management and the health of the caregiver. Let it be mentioned that more developed strategies were adopted such as the employment/recruitment of a housemaid and the help of other relatives. In sum, it can be concluded that there is a preferential tendency by families in seeking the complementarity of informal and formal support in order to provide the necessary care to the dependent elderly in the family environment.

Spatio-temporal analyses of the relationship between armed conflict and climate change in the eastern Africa

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Numerical methods and tangible interfaces for pollutant dispersion simulation

Dissertação apresentada para obtenção do Grau de Doutor em Engenharia do Ambiente, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Diabetes : percepção da doença e auto-cuidado

RESUMO - O aumento da prevalência da diabetes e a baixa adesão ao seu tratamento estão associados a um mau controlo metabólico, desenvolvimento de complicações, aumento dos custos económicos e ineficiência do sistema de saúde. De acordo com o modelo de auto-regulação, o estudo das representações da doença permite predizer os comportamentos dos doentes face a esta patologia. O objectivo do estudo é verificar a existência de relação entre a forma como os diabéticos tipo 2 percepcionam a sua doença, de acordo com o modelo de auto-regulação de Leventhal e colaboradores, e a adesão às actividades de auto-cuidado da diabetes. Consiste num estudo observacional, descritivo, analítico, do tipo transversal, a desenvolver em Cuidados de Saúde Primários. A amostra é constituída por 339 indivíduos diabéticos, de ambos os sexos, com idade igual ou superior a 20 anos e com diagnóstico de diabetes tipo 2 há mais de 6 meses. Trata-se de uma amostra probabilística, aleatória simples, seleccionada numa Unidade de Saúde Familiar (USF). A recolha de dados é realizada através do preenchimento de uma ficha de caracterização socio-demográfica e clínica, a partir do processo clínico electrónico, e através da aplicação de dois questionários de auto-preenchimento. Os resultados são analisados através do Statistical Program for Social Sciences (SPSS) – versão 17.0.

How do wages react to the business cycle? A microeconometric approach

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

The use of technology in Portuguese hospitals: The case of MRI

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Do hospitals react to random demand pressure by early discharges?

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Economic analysis in health care regulation : three essays

ABSTRACT - It is the purpose of the present thesis to emphasize, through a series of examples, the need and value of appropriate pre-analysis of the impact of health care regulation. Specifically, the thesis presents three papers on the theme of regulation in different aspects of health care provision and financing. The first two consist of economic analyses of the impact of health care regulation and the third comprises the creation of an instrument for supporting economic analysis of health care regulation, namely in the field of evaluation of health care programs. The first paper develops a model of health plan competition and pricing in order to understand the dynamics of health plan entry and exit in the presence of switching costs and alternative health premium payment systems. We build an explicit model of death spirals, in which profitmaximizing competing health plans find it optimal to adopt a pattern of increasing relative prices culminating in health plan exit. We find the steady-state numerical solution for the price sequence and the plan’s optimal length of life through simulation and do some comparative statics. This allows us to show that using risk adjusted premiums and imposing price floors are effective at reducing death spirals and switching costs, while having employees pay a fixed share of the premium enhances death spirals and increases switching costs. Price regulation of pharmaceuticals is one of the cost control measures adopted by the Portuguese government, as in many European countries. When such regulation decreases the products’ real price over time, it may create an incentive for product turnover. Using panel data for the period of 1997 through 2003 on drug packages sold in Portuguese pharmacies, the second paper addresses the question of whether price control policies create an incentive for product withdrawal. Our work builds the product survival literature by accounting for unobservable product characteristics and heterogeneity among consumers when constructing quality, price control and competition indexes. These indexes are then used as covariates in a Cox proportional hazard model. We find that, indeed, price control measures increase the probability of exit, and that such effect is not verified in OTC market where no such price regulation measures exist. We also find quality to have a significant positive impact on product survival. In the third paper, we develop a microsimulation discrete events model (MSDEM) for costeffectiveness analysis of Human Immunodeficiency Virus treatment, simulating individual paths from antiretroviral therapy (ART) initiation to death. Four driving forces determine the course of events: CD4+ cell count, viral load resistance and adherence. A novel feature of the model with respect to the previous MSDEMs is that distributions of time to event depend on individuals’ characteristics and past history. Time to event was modeled using parametric survival analysis. Events modeled include: viral suppression, regimen switch due virological failure, regimen switch due to other reasons, resistance development, hospitalization, AIDS events, and death. Disease progression is structured according to therapy lines and the model is parameterized with cohort Portuguese observational data. An application of the model is presented comparing the cost-effectiveness ART initiation with two nucleoside analogue reverse transcriptase inhibitors (NRTI) plus one non-nucleoside reverse transcriptase inhibitor(NNRTI) to two NRTI plus boosted protease inhibitor (PI/r) in HIV- 1 infected individuals. We find 2NRTI+NNRTI to be a dominant strategy. Results predicted by the model reproduce those of the data used for parameterization and are in line with those published in the literature.

Impact of health conditions on absenteeism from work

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics