Argumentation as Distributed Belief Revision: Conflict Resolution in Decentralised Multi-agent Systems

Decentralised co-operative multi-agent systems are computational systems where conflicts are frequent due to the nature of the represented knowledge. Negotiation methodologies, in this case argumentation based negotiation methodologies, were developed and applied to solve unforeseeable and, therefore, unavoidable conflicts. The supporting computational model is a distributed belief revision system where argumentation plays the decisive role of revision. The distributed belief revision system detects, isolates and solves, whenever possible, the identified conflicts. The detection and isolation of the conflicts is automatically performed by the distributed consistency mechanism and the resolution of the conflict, or belief revision, is achieved via argumentation. We propose and describe two argumentation protocols intended to solve different types of identified information conflicts: context dependent and context independent conflicts. While the protocol for context dependent conflicts generates new consensual alternatives, the latter chooses to adopt the soundest, strongest argument presented. The paper shows the suitability of using argumentation as a distributed decentralised belief revision protocol to solve unavoidable conflicts.

The debate on health in Portugal: governance of health care and the welfare modernization agenda

Comunicação apresentada na "Second Biennial Conference of the Standing Group on Regulation and Governance do ECPR Regulation & Governance, com o tema: (Re)Regulation in the Wake of Neoliberalism’ Consequences of Three Decades of Privatization and Market Liberalization, realizada na Universidade de Utrecht, the Netherlands, de 5 a 7 de Junho de 2008.

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.

Environment and Health in Children Day Care Centres (ENVIRH) - Study Rationale and Protocol

Background: Indoor air quality (IAQ) is considered an important determinant of human health. The association between exposure to volatile organic compounds, particulate matter, house dust mite, molds and bacteria in day care centers (DCC) is not completely clear. The aim of this project was to study these effects. Methods --- study design: This study comprised two phases. Phase I included an evaluation of 45 DCCs (25 from Lisbon and 20 from Oporto, targeting 5161 children). In this phase, building characteristics, indoor CO2 and air temperature/relative humidity, were assessed. A children’s respiratory health questionnaire derived from the ISAAC (International Study on Asthma and Allergies in Children) was also distributed. Phase II encompassed two evaluations and included 20 DCCs selected from phase I after a cluster analysis (11 from Lisbon and 9 from Oporto, targeting 2287 children). In this phase, data on ventilation, IAQ, thermal comfort parameters, respiratory and allergic health, airway inflammation biomarkers, respiratory virus infection patterns and parental and child stress were collected. Results: In Phase I, building characteristics, occupant behavior and ventilation surrogates were collected from all DCCs. The response rate of the questionnaire was 61.7% (3186 children). Phase II included 1221 children. Association results between DCC characteristics, IAQ and health outcomes will be provided in order to support recommendations on IAQ and children’s health. A building ventilation model will also be developed. Discussion: This paper outlines methods that might be implemented by other investigators conducting studies on the association between respiratory health and indoor air quality at DCC.

Supplementary private health insurance: The characteristics of subscribers

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

Primary and hospitalar health care: Building a happy marriage

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

Couch & Brunch: The breakfast chain business model

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

Inventory management for the health sector: ABC analysis approach

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

Technological adoption in health care

This paper addresses the impact of payment systems on the rate of technology adoption. We present a model where technological shift is driven by demand uncertainty, increased patients’ benefit, financial variables, and the reimbursement system to providers. Two payment systems are studied: cost reimbursement and (two variants of) DRG. According to the system considered, adoption occurs either when patients’ benefits are large enough or when the differential reimbursement across technologies offsets the cost of adoption. Cost reimbursement leads to higher adoption of the new technology if the rate of reimbursement is high relative to the margin of new vs. old technology reimbursement under DRG. Having larger patient benefits favors more adoption under the cost reimbursement payment system, provided that adoption occurs initially under both payment systems.

Mental health care assessed based on structure, process and outcome : a retrospective cohort study

RESUMO: As doenças mentais são comuns, universais e associadas a uma significativa sobrecarga pessoal, familiar, social e económica. Os Serviços de Saúde Mental devem abordar de forma adequada as necessidades dos pacientes e familiares tanto ao nível clínico como também ao nível social. O presente estudo foi realizado num período de grande transformação nos sistemas de saúde primário e de saúde mental em Portugal, num Departamento de Psiquiatria desenvolvido com base nos princípios da OMS. Os objectivos incluem a caracterização: 1) das Unidades Funcionais do Departamento; 2) dos pacientes internados pela primeira vez no internamento de agudos; 3) da utilização dos serviços nas equipas comunitárias após a alta; e 4) da avaliação de alguns dos indicadores de qualidade do departamento, com recurso ao modelo de Donabedian sobre a articulação entre a Estrutura-Processo-Resultados. Metodologia: Foi escolhido um estudo de coorte retrospectivo. Todos os pacientes internados pela primeira vez entre 2008 e 2010 foram incluídos no estudo. Os seus processos clínicos e a base de dados do hospital onde são registados todos os contactos que estes tiveram com os profissionais de saúde mental foram revistos de forma a obter dados sociodemográficos e clínicos, durante o período do estudo e após a alta. Os instrumentos utilizados foram o WHO-ICMHC (Classificação Internacional de Cuidados de Saúde Mental), para caracterizar o Departamento, o AIESMP (Avaliação Inicial de Enfermagem em Saúde Mental e Psiquiatria) para recolha dos dados sociodemográficos, e o VSSS (Escala de Satisfação com os Serviços de Verona) de forma a avaliar a satisfação dos pacientes em relação aos cuidados recebidos. A análise estatística incluiu a análise descritiva, quantitativa e qualitativa dos dados. Resultados: As Unidades Funcionais do Departamento revelaram níveis elevados de articulação e consistência com as necessidades de cuidados psiquiátricos e reabilitação psicossocial dos pacientes. Os 543 pacientes admitidos pela primeira vez eram maioritariamente (56.9%) mulheres, caucasianas (81.2%), com diagnóstico de perturbações do humor (66.3%), internadas voluntariamente (59.7%), e uma idade média de 45.1 anos. Estas eram significativamente mais velhas, mais frequentemente empregadas, casadas/coabitar e tinham uma prevalência mais elevada de perturbações do humor, comparativamente aos homens. O internamento compulsivo era mais significativo nos homens (54.7%). A taxa de abandono no pós-alta (4.2%) e a taxa de reinternamentos (2.9%) na quinzena após a alta revelaram-se inferiores aos padrões na literatura internacional. De forma global, a satisfação dos pacientes com os cuidados de saúde mental foi positiva. Conclusões: Os cuidados prestados mostraram-se eficazes, adaptados e baseados nas necessidades e problemas específicos dos pacientes. A continuidade e a abrangência de cuidados foram difundidos e mantidos ao longo do processo de cuidados. Este Departamento pode ser considerado um exemplo de como proporcionar tratamento digno e eficiente, e uma referência para futuros serviços de psiquiatria.-------------- ABSTRACT: Mental health disorders are common, universal, and associated with heavy personal, family, social and economic burden. Mental health services should be aimed at adequately addressing patients’ and families’ needs at clinical and social level. The current study was carried out at a time of great transformation in the health and mental health systems in Portugal, in a Psychiatric Department developed taking in consideration the WHO principles. The objectives included characterizing: 1) the Psychiatric Department’s different units; 2) the patients admitted for the first time to the inpatient unit; 3) their use of community mental health services after discharge; and 4) assessing some of the department’s quality indicators, with resource to Donabedian’s Structure-Process-Outcome model. Methodology: A retrospective cohort design was chosen. All the firstly admitted patients in the period between 2008 and 2010 were included in the study. Their clinical records and the hospital’s database which registers all of the contacts the patients had with the mental health professionals during the study period, were reviewed to retrieve sociodemographic and clinical data and information on follow-up. The instruments used were the WHO International Classification of Mental Health Care (ICMHC) to characterize the department, the Initial Nurses’ Assessment in Mental Health and Psychiatry (AIESMP) for patients’ sociodemographic data, and the Verona Service Satisfaction Scale (VSSS) to assess patients’ satisfaction with care received. Statistical analysis included descriptive, quantitative and qualitative analysis of the data. Results: The Department’s Functional units revealed high levels of articulation, and were consistent with patients’ needs for psychiatric care and psychosocial rehabilitation. The 543 patients firstly admitted were mainly (56.9%) female, Caucasian (81.2%), diagnosed with mood disorders (66.3%), voluntarily admitted (59.7%), and with a mean age of 45.1 years. Female patients were significantly older, more frequently employed, married/cohabiting and had a higher prevalence of mood disorders when compared to males. Involuntary admission was more significant in males (54.7%). Dropout rates during follow-up (4.2%) and readmission rates (2.9%) in the fortnight following discharge were lower than standards in international literature. Overall patients’ satisfaction with mental health care was positive. Conclusions: The care delivered was effective, adapted and based on the patients’ specific needs and problems. Continuity and comprehensiveness of care was endorsed and maintained throughout the care process. This department may be considered an example of both humane and effective treatment, and a reference for future psychiatric care.

Catastrophic health care expenditures in Portugal between 2000-2010: Assessing impoverishment, determinants and policy implications

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

Environmental sanitation conditions and health impact: a case-control study

This epidemiological investigation examines the impact of several environmental sanitation conditions and hygiene practices on diarrhea occurrence among children under five years of age living in an urban area. The case-control design was employed; 997 cases and 999 controls were included in the investigation. Cases were defined as children with diarrhea and controls were randomly selected among children under five years of age. After logistic regression adjustment, the following variables were found to be significantly associated with diarrhea: washing and purifying fruit and vegetables; presence of wastewater in the street; refuse storage, collection and disposal; domestic water reservoir conditions; feces disposal from swaddles; presence of vectors in the house and flooding in the lot. The estimates of the relative risks reached values up to 2.87. The present study revealed the feasibility of developing and implementing an adequate model to establish intervention priorities in the field of environmental sanitation.

How to optimize Lipton’s business model in order to stimulate tea consumption in Portugal and increase Lipton Leaf tea market share?: The importance of distribution and sales channels management in a B2B2C market

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