A proof system for lock-free concurrency

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Validation of NASA rotor 67 with openFOAM's transonic density-based solver

Dissertação para obtenção do Grau de Mestre em Engenharia Mecânica

Referenda outcomes and the influence of polls: A social network feedback process

This paper proposes a model to explain the differences between outcomes of referenda and the voting trends suggested by polls. Two main effects are at stake. First, the evolution of the voters' attitudes is conditional on the public information made available to them. Second, the predisposition toward abstention among individuals within each voting group may be different. Our model describes how these two aspects of decision making may interact, showing how publicly available information may amplify the distinct tendency toward abstention between both groups and thus affect the outcome of the referendum.

Study of the electromyographic signal dynamic behavior in Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by motor neurons degeneration, which reduces muscular force, being very difficult to diagnose. Mathematical methods are used in order to analyze the surface electromiographic signal’s dynamic behavior (Fractal Dimension (FD) and Multiscale Entropy (MSE)), evaluate different muscle group’s synchronization (Coherence and Phase Locking Factor (PLF)) and to evaluate the signal’s complexity (Lempel-Ziv (LZ) techniques and Detrended Fluctuation Analysis (DFA)). Surface electromiographic signal acquisitions were performed in upper limb muscles, being the analysis executed for instants of contraction for ipsilateral acquisitions for patients and control groups. Results from LZ, DFA and MSE analysis present capability to distinguish between the patient group and the control group, whereas coherence, PLF and FD algorithms present results very similar for both groups. LZ, DFA and MSE algorithms appear then to be a good measure of corticospinal pathways integrity. A classification algorithm was applied to the results in combination with extracted features from the surface electromiographic signal, with an accuracy percentage higher than 70% for 118 combinations for at least one classifier. The classification results demonstrate capability to distinguish members between patients and control groups. These results can demonstrate a major importance in the disease diagnose, once surface electromyography (sEMG) may be used as an auxiliary diagnose method.

Caraterização da tomada de decisão em organizações hospitalares : impacto do estatuto jurídico

RESUMO - O decisor hospitalar tem como função decidir os recursos de uma organização de saúde, sejam estes financeiros, materiais ou humanos, sendo decisivo o conhecimento e informação que o apoiem na aplicabilidade nas tomadas de decisão e na solução dos problemas. As tomadas de decisão suportam-se em modelos reproduzidos pelos decisores, em processos, modelos, e em princípios, que podem ou não assumir intuição, objetividade, racionalidade e ética, bem como de técnicas várias que podem ser limitativas ou condicionadas, por força de fatores vários, como: a falta de informação inerente de uma multidisciplinaridade do processo; de condicionalismos organizacionais, internos ou externos, associados à envolvente e cultura organizacional e influências políticas e macroeconómicas; ao fator tempo; a tecnologia; a estrutura e desenho organizacional; a autoridade/poder e a autonomia para decidir; a liderança, e do estatuto jurídico que o hospital possui. Este último ponto será esmiuçado, mais profundamente, neste estudo. Iremos, através do estudo, compreender se os elementos componentes das decisões tomadas nos hospitais, são ou não adaptadas em consonância com diferentes políticas de governação hospitalar, em contextos e dinâmicas organizacionais diferenciadas, por diferentes Estatutos Jurídicos Hospitalares - EPE, SPA, PPP e Privados. Foi realizado um estudo de caráter exploratório, descritivo-correlacional e transversal, baseou-se num questionário aplicado a decisores hospitalares, incidindo nos dois vetores centrais do estudo, na tomada de decisão e no estatuto jurídico hospitalar. A decisão é então, um valiosíssimo veículo na persecução das estratégias e planos formulados pelo hospital, esperando-se destes produzir consequentes resultados eficientes, eficazes e efetivos na sua aplicação.

Cellular reprogramming strategies for degenerative disorders involving the retinal pigment epithelium

RESUMO: A reprogramação celular permite que uma célula somática seja reprogramada para outra célula diferente através da expressão forçada de factores de transcrição (FTs) específicos de determinada linhagem celular, e constitui uma área de investigação emergente nos últimos anos. As células somáticas podem ser experimentalmente manipuladas de modo a obter células estaminais pluripotentes induzidas (CEPi), ou convertidas directamente noutro tipo de célula somática. Estas descobertas inovadoras oferecem oportunidades promissoras para o desenvolvimento de novas terapias de substituição celular e modelos de doença, funcionando também como ferramentas valiosas para o estudo dos mecanismos moleculares que estabelecem a identidade celular e regulam os processos de desenvolvimento. Existem várias doenças degenerativas hereditárias e adquiridas da retina que causam deficiência visual devido a uma disfunção no tecido de suporte da retina, o epitélio pigmentar da retina (EPR). Uma destas doenças é a Coroideremia (CHM), uma doença hereditária monogénica ligada ao cromossoma X causada por mutações que implicam a perda de função duma proteína com funções importantes na regulação do tráfico intracelular. A CHM é caracterizada pela degenerescência progressiva do EPR, assim como dos foto-receptores e da coróide. Resultados experimentais sugerem que o EPR desempenha um papel importante na patogénese da CHM, o que parece indicar uma possível vantagem terapêutica na substituição do EPR nos doentes com CHM. Por outro lado, existe uma lacuna em termos de modelos in vitro de EPR para estudar a CHM, o que pode explicar o ainda desconhecimento dos mecanismos moleculares que explicam a patogénese desta doença. Assim, este trabalho focou-se principalmente na exploração das potencialidades das técnicas de reprogramação celular no contexto das doenças de degenerescência da retina, em particular no caso da CHM. Células de murganho de estirpe selvagem, bem como células derivadas de um ratinho modelo de knockout condicional de Chm, foram convertidos com sucesso em CEPi recorrendo a um sistema lentiviral induzido que permite a expressão forçada dos 4 factores clássicos de reprogramação, a saber Oct4, Sox2, Klf4 e c-Myc. Estas células mostraram ter equivalência morfológica, molecular e funcional a células estaminais embrionárias (CES). As CEPi obtidas foram seguidamente submetidas a protocolos de diferenciação com o objectivo final de obter células do EPR. Os resultados promissores obtidos revelam a possibilidade de gerar um valioso modelo de EPR-CHM para estudos in vitro. Em alternativa, a conversão directa de linhagens partindo de fibroblastos para obter células do EPR foi também abordada. Uma vasta gama de ferramentas moleculares foi gerada de modo a implementar uma estratégia mediada por FTs-chave, seleccionados devido ao seu papel fundamental no desenvolvimento embrionário e especificação do EPR. Conjuntos de 10 ou menos FTs foram usados para transduzir fibroblastos, que adquiriram morfologia pigmentada e expressão de alguns marcadores específicos do EPR. Adicionalmente, observou-se a activação de regiões promotoras de genes específicos de EPR, indicando que a identidade transcricional das células foi alterada no sentido pretendido. Em conclusão, avanços significativos foram atingidos no sentido da implementação de tecnologias de reprogramação celular já estabelecidas, bem como na concepção de novas estratégias inovadoras. Metodologias de reprogramação, quer para pluripotência, quer via conversão directa, foram aplicadas com o objectivo final de gerar células do EPR. O trabalho aqui descrito abre novos caminhos para o estabelecimento de terapias de substituição celular e, de uma maneira mais directa, levanta a possibilidade de modelar doenças degenerativas da retina com disfunção do EPR numa placa de petri, em particular no caso da CHM.---------------ABSTRACT: Cellular reprogramming is an emerging research field in which a somatic cell is reprogrammed into a different cell type by forcing the expression of lineage-specific transcription factors (TFs). Cellular identities can be manipulated using experimental techniques with the attainment of pluripotency properties and the generation of induced Pluripotent Stem (iPS) cells, or the direct conversion of one somatic cell into another somatic cell type. These pioneering discoveries offer new unprecedented opportunities for the establishment of novel cell-based therapies and disease models, as well as serving as valuable tools for the study of molecular mechanisms governing cell fate establishment and developmental processes. Several retinal degenerative disorders, inherited and acquired, lead to visual impairment due to an underlying dysfunction of the support cells of the retina, the retinal pigment epithelium (RPE). Choroideremia (CHM), an X-linked monogenic disease caused by a loss of function mutation in a key regulator of intracellular trafficking, is characterized by a progressive degeneration of the RPE and other components of the retina, such as the photoreceptors and the choroid. Evidence suggest that RPE plays an important role in CHM pathogenesis, thus implying that regenerative approaches aiming at rescuing RPE function may be of great benefit for CHM patients. Additionally, lack of appropriate in vitro models has contributed to the still poorly-characterized molecular events in the base of CHM degenerative process. Therefore, the main focus of this work was to explore the potential applications of cellular reprogramming technology in the context of RPE-related retinal degenerations. The generation of mouse iPS cells was established and optimized using an inducible lentiviral system to force the expression of the classic set of TFs, namely Oct4, Sox2, Klf4 and c-Myc. Wild-type cells, as well as cells derived from a conditional knockout (KO) mouse model of Chm, were successfully converted into a pluripotent state, that displayed morphology, molecular and functional equivalence to Embryonic Stem (ES) cells. Generated iPS cells were then subjected to differentiation protocols towards the attainment of a RPE cell fate, with promising results highlighting the possibility of generating a valuable Chm-RPE in vitro model. In alternative, direct lineage conversion of fibroblasts into RPE-like cells was also tackled. A TF-mediated approach was implemented after the generation of a panoply of molecular tools needed for such studies. After transduction with pools of 10 or less TFs, selected for their key role on RPE developmental process and specification, fibroblasts acquired a pigmented morphology and expression of some RPE-specific markers. Additionally, promoter regions of RPE-specific genes were activated indicating that the transcriptional identity of the cells was being altered into the pursued cell fate. In conclusion, highly significant progress was made towards the implementation of already established cellular reprogramming technologies, as well as the designing of new innovative ones. Reprogramming into pluripotency and lineage conversion methodologies were applied to ultimately generate RPE cells. These studies open new avenues for the establishment of cell replacement therapies and, more straightforwardly,raise the possibility of modelling retinal degenerations with underlying RPE defects in apetri dish, particularly CHM.

Flexible multivariate GARCH modeling with an application to international stock markets

This paper offers a new approach to estimating time-varying covariance matrices in the framework of the diagonal-vech version of the multivariate GARCH(1,1) model. Our method is numerically feasible for large-scale problems, produces positive semidefinite conditional covariance matrices, and does not impose unrealistic a priori restrictions. We provide an empirical application in the context of international stock markets, comparing the nev^ estimator with a number of existing ones.

Compensating variation and the young Portuguese emigrants: A study on how to keep our own

Emigration has been a very present word in Portugal. Due to the effects of the Economic Crisis and the Memorandum of Understanding policies, we have witnessed a significant yearly migration outflow of people searching for better conditions. This study aims to measure the factors affecting this flow as well as how much the probability of emigrating has evolved during the years bridging 2006 to 2012. I shall consider the decision of emigrating as Discrete Choice Random Utility maximization use a conditional Logit framework to model the probability choice for 31 OECD countries of destination. Moreover I will ascertain the compensating variation required such that the probability of choice in 2012 is adjusted back to 2007 values, keeping all other variables constant. I replicate this exercise using the unemployment rate instead of income. The most likely country of destination is Luxembourg throughout the years analyzed and the values obtained for the CV is of circa 1.700€ in terms of Income per capita and -11% in terms of the unemployment rate adjustment.

What hides behind the fixed-term contracts wage gap?

In Portugal, about 20% of full-time workers are employed under a fixed-term contract. Using a rich longitudinal matched employer-employee dataset for Portugal, with more than 20 million observations and covering the 2002-2012 period, we confirm the common idea that fixed-term contracts are not desirable when compared to permanent ones, by estimating a conditional wage gap of -1.7 log points. Then, we evaluate the sources of that wage penalty by combining a three way high-dimensional fixed effects model with the decomposition of Gelbach (2014), in which the three dimensions considered are the worker’s unobserved ability, the firm’s compensation wage policy and the job title effect. It is shown that the average worker with a fixed-term contract is less productive than his/her permanent counterparts, explaining -3.92 log points of the FTC wage penalty. Additionally, the sorting of workers into lower-paid job titles is also responsible for -0.59 log points of the wage gap. Surprisingly, we found that the allocation of workers among firms mitigates the existing wage penalty (in 4.23 log points), as fixed-term workers are concentrated into firms with a more generous compensation policy. Finally, following Figueiredo et al. (2014), we further control for the worker-firm match characteristics and reach the conclusion that fixed-term employment relationships have an overrepresentation of low quality worker-firm matches, explaining 0.65 log points of the FTC wage penalty.

Fatores de prognóstico para os resultados de sucesso da fisioterapia multimodal em utentes com dor cervical crónica

RESUMO: Introdução: O conhecimento acerca da influência das características dos indivíduos com dor cervical crónica (DCC) no prognóstico dos resultados alcançados com a Fisioterapia é ainda inconsistente, sendo escassos os estudos desenvolvidos neste âmbito. Objetivo: Este relatório pretende determinar se um modelo baseado em fatores de prognóstico é capaz de prever os resultados de sucesso da Fisioterapia, a curto prazo, em utentes com DCC, ao nível da incapacidade funcional, intensidade da dor e perceção global de melhoria. Metodologia: Trata-se de estudo de coorte prospetivo com 112 participantes. Os utentes foram avaliados na primeira semana de tratamento e sete semanas após o início da intervenção. Os instrumentos utilizados foram o Neck Disability Index–Versão Portuguesa (NDI-PT) e a Escala Numérica da Dor (END) nos dois momentos de avaliação, um Questionário de Caracterização Sociodemográfica e Clínica da Amostra na baseline e a Patient Global Impression Change Scale–Versão Portuguesa (PGIC-PT) no follow-up. As características sociodemográficas e clínicas foram incluídas como potenciais fatores de prognóstico e estes foram definidos com base nas diferenças mínimas clinicamente importantes (DMCI) dos instrumentos NDIPT (DMCI≥6) e END (DMCI≥2) e no critério de pontuação ≥5 na PGIC-PT. A análise dos dados foi realizada através do método de regressão logística (backward conditional procedure) para identificar as associações entre os indicadores e as variáveis de resultado (p<0.05). Resultados: Dos 112 participantes incluídos no estudo, 108 completaram o follow-up (média de idade: 51.76±10.19). No modelo multivariado relativo à incapacidade funcional, os resultados de sucesso encontram-se associados a elevados níveis de incapacidade na baseline (OR=1.123; 95% IC 1.056–1.194) e a duração da dor inferior a 12 meses (OR=2.704; 95% IC 1.138–6.424). Este modelo explica 30.0% da variância da melhoria da funcionalidade e classifica corretamente 74.1% dos utentes (sensibilidade: 75.9%; especificidade: 72.0%). O modelo relativo à intensidade da dor identificou apenas a associação do outcome com níveis elevados de intensidade da dor na baseline (OR=1.321; 95% IC 1.047–1.668), explicando 7.5% da variância da redução da mesma e classificando corretamente 68.2% dos utentes (sensibilidade: 94.4%; especificidade: 16.7%). O modelo final referente à perceção global de melhoria apresentou uma associação com a intensidade da dor na baseline (OR=0.621; 95% IC 0.465–0.829), com a presença de cefaleias e/ou tonturas (OR=2.538; 95% IC 0.987–6.526) e com a duração da dor superior a 12 meses (OR=0.279; 95% IC 0.109–0.719). Este modelo explica 27.5% da variância dos resultados de sucesso para este outcome e classifica corretamente 73.1% dos utentes (sensibilidade: 81.8%; especificidade: 59.5%). Conclusões: Utentes com DCC com elevada incapacidade na baseline e queixas de dor há menos de 12 meses apresentam maior probabilidade de obter melhorias ao nível da incapacidade funcional. Elevados níveis de intensidade da dor na baseline predizem resultados de sucesso na redução da dor após sete semanas de tratamento. Utentes com DCC com baixos níveis de dor na baseline, com cefaleias e/ou tonturas e com queixas de dor há mais de 12 meses apresentam maior probabilidade de obter uma melhor perceção de melhoria.--------------- ABSTRACT:Introduction: The influence of the characteristics of individuals with chronic neck pain (CNP) on the prognosis of physiotherapy outcomes is still inconsistent, there being few studies developed in this context. Aim: This study seeks to determine whether a model based on prognostic factors can predict the short-term physiotherapy successful outcomes in CNP patients, regarding functional disability, pain intensity and perceived recovery. Methodology: This is a prospective cohort study with 112 participants. Patients were assessed during the first week of treatment and seven weeks after the start of the intervention. The instruments used were the Neck Disability Index–Portuguese Version (NDI-PT) and the Numerical Rating Scale (NRS) at both moments of assessment, a Sample Sociodemographic and Clinical Characterization Questionnaire at baseline and Patient Global Impression Change Scale–Portuguese Version (PGIC-PT) at the follow-up. The sociodemographic and clinical characteristics were included as potential predictors of successful outcomes, and these were defined on the basis of minimal clinically important differences (MCID) of NDI-PT (MCID≥6) and END (MCID≥2) and the criteria score ≥5 on the PGIC-PT. Data analysis was performed using logistic regression (backward conditional procedure) to identify associations between predictors and outcomes (p<0.05). Results: Of the 112 participants included in the study, 108 completed the follow-up (mean age: 51.76±10.19). In the multivariate model of functional disability, the successful outcomes are associated with high levels of disability at baseline (OR = 1.123; 95% CI 1.056-1.194), and pain duration shorter than 12 months (OR=2.704; 95% CI 1.138–6.424). This model explains 30.0% of the variance of improved functional capacity and correctly classifies 74.1% of the patients (sensitivity: 75.9%, specificity: 72.0%). The model for pain intensity solely identified an outcome association with high pain intensity at baseline (OR=1.321; 95% CI 1.047-1.668), explaining 7.5% of the variance of pain reduction and correctly classifying 68.2% of the patients (sensitivity: 94.4%, specificity: 16.7%). The final model of perceived recovery showed an association with pain intensity at baseline (OR=0.621; 95% CI 0465-0829), with the presence of headache and/or dizziness (OR=2.538; 95% CI 0.987-6.526) and the duration of pain over 12 months (OR=0.279; 95% CI 0.109-0.719). This model explains 27.5% of the variance of successful outcomes and correctly classifies 73.1% of the patients (sensitivity: 81.8%, specificity: 59.5%). Conclusions: Patients with CNP with high disability at baseline and complaints of pain for less than 12 months are more likely to obtain improvements in functional disability. High levels of pain intensity at baseline predict successful outcomes in pain reduction after seven weeks of treatment. Patients with CNP with low levels of pain at baseline, with headache and/or dizziness and with pain complaints for more than 12 months are more likely to get a better perceived recovery.

Curso clínico da dor lombar crónica após alta da fisioterapia : trajetórias de dor no follow-up aos quatro e seis meses

RESUMO:Introdução: O conhecimento acerca da influência das características dos indivíduos com dor cervical crónica (DCC) no prognóstico dos resultados alcançados com a Fisioterapia é ainda inconsistente, sendo escassos os estudos desenvolvidos neste âmbito. Objetivo: Este relatório pretende determinar se um modelo baseado em fatores de prognóstico é capaz de prever os resultados de sucesso da Fisioterapia, a curto prazo, em utentes com DCC, ao nível da incapacidade funcional, intensidade da dor e perceção global de melhoria. Metodologia: Trata-se de estudo de coorte prospetivo com 112 participantes. Os utentes foram avaliados na primeira semana de tratamento e sete semanas após o início da intervenção. Os instrumentos utilizados foram o Neck Disability Index–Versão Portuguesa (NDI-PT) e a Escala Numérica da Dor (END) nos dois momentos de avaliação, um Questionário de Caracterização Sociodemográfica e Clínica da Amostra na baseline e a Patient Global Impression Change Scale–Versão Portuguesa (PGIC-PT) no follow-up. As características sociodemográficas e clínicas foram incluídas como potenciais fatores de prognóstico e estes foram definidos com base nas diferenças mínimas clinicamente importantes (DMCI) dos instrumentos NDIPT (DMCI≥6) e END (DMCI≥2) e no critério de pontuação ≥5 na PGIC-PT. A análise dos dados foi realizada através do método de regressão logística (backward conditional procedure) para identificar as associações entre os indicadores e as variáveis de resultado (p<0.05). Resultados: Dos 112 participantes incluídos no estudo, 108 completaram o follow-up (média de idade: 51.76±10.19). No modelo multivariado relativo à incapacidade funcional, os resultados de sucesso encontram-se associados a elevados níveis de incapacidade na baseline (OR=1.123; 95% IC 1.056–1.194) e a duração da dor inferior a 12 meses (OR=2.704; 95% IC 1.138–6.424). Este modelo explica 30.0% da variância da melhoria da funcionalidade e classifica corretamente 74.1% dos utentes (sensibilidade: 75.9%; especificidade: 72.0%). O modelo relativo à intensidade da dor identificou apenas a associação do outcome com níveis elevados de intensidade da dor na baseline (OR=1.321; 95% IC 1.047–1.668), explicando 7.5% da variância da redução da mesma e classificando corretamente 68.2% dos utentes (sensibilidade: 94.4%; especificidade: 16.7%). O modelo final referente à perceção global de melhoria apresentou uma associação com a intensidade da dor na baseline (OR=0.621; 95% IC 0.465–0.829), com a presença de cefaleias e/ou tonturas (OR=2.538; 95% IC 0.987–6.526) e com a duração da dor superior a 12 meses (OR=0.279; 95% IC 0.109–0.719). Este modelo explica 27.5% da variância dos resultados de sucesso para este outcome e classifica corretamente 73.1% dos utentes (sensibilidade: 81.8%; especificidade: 59.5%). Conclusões: Utentes com DCC com elevada incapacidade na baseline e queixas de dor há menos de 12 meses apresentam maior probabilidade de obter melhorias ao nível da incapacidade funcional. Elevados níveis de intensidade da dor na baseline predizem resultados de sucesso na redução da dor após sete semanas de tratamento. Utentes com DCC com baixos níveis de dor na baseline, com cefaleias e/ou tonturas e com queixas de dor há mais de 12 meses apresentam maior probabilidade de obter uma melhor perceção de melhoria.-----------ABSTRACT: Introduction: The influence of the characteristics of individuals with chronic neck pain (CNP) on the prognosis of physiotherapy outcomes is still inconsistent, there being few studies developed in this context. Aim: This study seeks to determine whether a model based on prognostic factors can predict the short-term physiotherapy successful outcomes in CNP patients, regarding functional disability, pain intensity and perceived recovery. Methodology: This is a prospective cohort study with 112 participants. Patients were assessed during the first week of treatment and seven weeks after the start of the intervention. The instruments used were the Neck Disability Index–Portuguese Version (NDI-PT) and the Numerical Rating Scale (NRS) at both moments of assessment, a Sample Sociodemographic and Clinical Characterization Questionnaire at baseline and Patient Global Impression Change Scale–Portuguese Version (PGIC-PT) at the follow-up. The sociodemographic and clinical characteristics were included as potential predictors of successful outcomes, and these were defined on the basis of minimal clinically important differences (MCID) of NDI-PT (MCID≥6) and END (MCID≥2) and the criteria score ≥5 on the PGIC-PT. Data analysis was performed using logistic regression (backward conditional procedure) to identify associations between predictors and outcomes (p<0.05). Results: Of the 112 participants included in the study, 108 completed the follow-up (mean age: 51.76±10.19). In the multivariate model of functional disability, the successful outcomes are associated with high levels of disability at baseline (OR = 1.123; 95% CI 1.056-1.194), and pain duration shorter than 12 months (OR=2.704; 95% CI 1.138–6.424). This model explains 30.0% of the variance of improved functional capacity and correctly classifies 74.1% of the patients (sensitivity: 75.9%, specificity: 72.0%). The model for pain intensity solely identified an outcome association with high pain intensity at baseline (OR=1.321; 95% CI 1.047- 1.668), explaining 7.5% of the variance of pain reduction and correctly classifying 68.2% of the patients (sensitivity: 94.4%, specificity: 16.7%). The final model of perceived recovery showed an association with pain intensity at baseline (OR=0.621; 95% CI 0465-0829), with the presence of headache and/or dizziness (OR=2.538; 95% CI 0.987-6.526) and the duration of pain over 12 months (OR=0.279; 95% CI 0.109- 0.719). This model explains 27.5% of the variance of successful outcomes and correctly classifies 73.1% of the patients (sensitivity: 81.8%, specificity: 59.5%). Conclusions: Patients with CNP with high disability at baseline and complaints of pain for less than 12 months are more likely to obtain improvements in functional disability. High levels of pain intensity at baseline predict successful outcomes in pain reduction after seven weeks of treatment. Patients with CNP with low levels of pain at baseline, with headache and/or dizziness and with pain complaints for more than 12 months are more likely to get a better perceived recovery.

Modeling and forecasting value-at-risk for the Portuguese stock market

The aim of this work project is to find a model that is able to accurately forecast the daily Value-at-Risk for PSI-20 Index, independently of the market conditions, in order to expand empirical literature for the Portuguese stock market. Hence, two subsamples, representing more and less volatile periods, were modeled through unconditional and conditional volatility models (because it is what drives returns). All models were evaluated through Kupiec’s and Christoffersen’s tests, by comparing forecasts with actual results. Using an out-of-sample of 204 observations, it was found that a GARCH(1,1) is an accurate model for our purposes.

Banking crises: The impact of financial liberalization

This paper intends to study whether financial liberalization tends to increase the likelihood of systemic banking crises. I used a sample of 79 countries with data spanning from 1973 to 2005 to run a panel probit model. I found that, if anything, financial liberalization as measured across seven different dimensions tends to decrease the probability of occurrence of a systemic banking crisis. I went further and did several robustness tests – used a conditional probit model, tested for different durations of liberalization impact and reduced the sample by considering only the first crisis event for each country. Main results still verified, proving the results’ robustness.

Stops and bonanzas in the EU: Does being part of the Euro Area make a difference?

In this paper, we investigate whether being part of the euro area influences the conditional probability of going through a sudden stop or a bonanza of capital flows. Our sample period is from 1995 until 2014. We identify these two phenomena and we evaluate which push and pull factors help predict the conditional probability of experiencing one of them. We find that most countries had significant capital inflows until 2008 and that there were more sudden stops during the recent financial crisis than in any other moment in our sample. The factors that better help forecast the conditional probability of a sudden stop are global uncertainty (represented by the push factor “Volatility Index”), and the domestic economic activity (pull factors “GDP growth” and “consumer confidence”). An indicator of country risk (pull factor “change in credit rating”) is the most significant one for predicting bonanzas. Ultimately, we find no evidence that being part of the euro area influences the conditional probability of going through a sudden stop or a bonanza.

Fractional state space analysis of economic systems

This paper examines modern economic growth according to the multidimensional scaling (MDS) method and state space portrait (SSP) analysis. Electing GDP per capita as the main indicator for economic growth and prosperity, the long-run perspective from 1870 to 2010 identifies the main similarities among 34 world partners’ modern economic growth and exemplifies the historical waving mechanics of the largest world economy, the USA. MDS reveals two main clusters among the European countries and their old offshore territories, and SSP identifies the Great Depression as a mild challenge to the American global performance, when compared to the Second World War and the 2008 crisis.