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  • The role of miniaturized systems in analytical toxicology: new psychoactive substances
    Publication . Moreno, Ivo Emanuel Dias; Gallardo Alba, Maria Eugénia; Barroso, Mário Jorge Dinis; Cruz Landeira, Angelines
    In recent years new psychoactive substances (NPS) have emerged, sold via the Internet as licit drugs of abuse. These compounds, also called "legal highs", are designed as substitutes for illegal drugs, causing similar effects. In Portugal, as in the rest of the world, their abuse as well as their effects and consequences in the life of individuals and society, has become increasingly alarming and with great social impact, claiming more attention from health professionals. As such, due to lack of scientific information in this context, there is a clear need to provide laboratories with tools for combating this situation, by means of methods development to identify and quantify these emerging psychoactive substances. The objectives of this thesis were the development, optimization and validation of extractive and chromatographic techniques for the identification and quantification of new psychoactive drugs available in Portugal, namely salvinorin A, ketamine (K) and its major metabolite norketamine (NK) and methoxetamine (MXE) in samples of toxicological interest (plasma and urine). Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) was the chosen chromatographic technique. Sample preparation was carried out through microextraction in packed sorbent (MEPS), and for a better efficiency of the extraction process, all parameters susceptible of influencing the procedure were optimized using a powerful statistical tool, the Design of Experiments (DOE). To verify that the analytical method was suitable for its intended purpose, it has been validated according to internationally accepted criteria. The methodologies proved to be selective, linear within the studied concentration ranges, with determination coefficients greater than 0.99 for all analytes and presenting limits of detection of 5 ng/mL for salvinorin A, K, and NK and 1 ng/mL for MXE. Under optimized conditions, recovery values ranged from 71 to 80% for salvinorin A, 73-101% for K and NK in urine and 63-89% in plasma, 80-110% and 81-88% for MXE in urine and plasma, respectively. To evaluate the applicability of the present methods, they were applied to real samples; however, none of the psychoactive substances was detected, with exception of mCPP. MEPS proved to be a fast and easy-to-use procedure for the determination of selected drugs in urine and plasma samples, reducing costs and time of analysis. Furthermore, the use of reduced volumes of biological sample makes the method a valuable tool for the determination of the studied compounds, for example in situations of clinical and forensic context.
    2016-06Doctoral thesis Open access Show more
  • Realistic simulation and animation of clouds using SkewT-LogP diagrams
    Publication . Duarte, Rui Pedro Monteiro Amaro; Gomes, Abel João Padrão
    Nuvens e clima são tópicos importantes em computação gráfica, nomeadamente na simulação e animação de fenómenos naturais. Tal deve-se ao facto de a simulação de fenómenos naturais−onde as nuvens estão incluídas−encontrar aplicações em filmes, jogos e simuladores de voo. Contudo, as técnicas existentes em computação gráfica apenas permitem representações de nuvens simplificadas, tornadas possíveis através de dinâmicas fictícias que imitam a realidade. O problema que este trabalho pretende abordar prende-se com a simulação de nuvens adequadas para utilização em ambientes virtuais, isto é, nuvens com dinâmica baseada em física que variam ao longo do tempo. Em meteorologia é comum usar técnicas de simulação de nuvens baseadas em leis da física, contudoossistemasatmosféricosdeprediçãonuméricasãocomputacionalmente pesados e normalmente possuem maior precisão numérica do que o necessário em computação gráfica. Neste campo, torna-se necessário direcionar e ajustar as características físicas ou contornar a realidade de modo a atingir os objetivos artísticos, sendo um fator fundamental que faz com que a computação gráfica se distinga das ciências físicas. Contudo, simulações puramente baseadas em física geram soluções de acordo com regras predefinidas e tornam-se notoriamente difíceis de controlar. De modo a enfrentar esses desafios desenvolvemos um novo método de simulação de nuvens baseado em física que possui a característica de ser computacionalmente leve e simula as propriedades dinâmicas relacionadas com a formação de nuvens. Este novo modelo evita resolver as equações físicas, ao apresentar uma solução explícita para essas equações através de diagramas termodinâmicos SkewT/LogP. O sistema incorpora dados reais de forma a simular os parâmetros necessários para a formação de nuvens. É especialmente adequado para a simulação de nuvens cumulus que se formam devido ao um processo convectivo. Esta abordagem permite não só reduzir os custos computacionais de métodos baseados em física, mas também fornece a possibilidade de controlar a forma e dinâmica de nuvens através do controlo dos níveis atmosféricos existentes no diagrama SkewT/LogP. Nestatese,abordámostambémumoutrodesafio,queestárelacionadocomasimulação de nuvens orográficas. Do nosso conhecimento, esta é a primeira tentativa de simular a formação deste tipo de nuvens. A novidade deste método reside no fato de este tipo de nuvens serem não convectivas, oque se traduz nocálculodeoutrosníveis atmosféricos. Além disso, atendendo a que este tipo de nuvens se forma sobre montanhas, é também apresentadoumalgoritmoparadeterminarainfluênciadamontanhasobreomovimento da nuvem. Em resumo, esta dissertação apresenta um conjunto de algoritmos para a modelação e simulação de nuvens cumulus e orográficas, recorrendo a diagramas termodinâmicos SkewT/LogP pela primeira vez no campo da computação gráfica.
    2016-06Doctoral thesis Open access Show more
  • Parlamento jovem: a experiência do protagonismo juvenil no projeto deputado universitário tocantinense
    Publication . Albernaz, V. B.; Benini, Edi Augusto; Salve, Guilherme
    Os programas Parlamentos Jovens (PJs) são espaços que promovem maior aproximação do Poder Legislativo com os jovens e que buscam envolvê-los na participação político-cidadã, por meio do conhecimento prático do funcionamento do parlamento. O presente estudo propõe uma avaliação da experiência de jovens universitários no projeto Deputado Universitário Tocantinense (DUT) e busca ainda entender a contribuição da iniciativa em sua formação política, cidadã e profissional. O percurso metodológico utilizado para a realização da pesquisa foi o método quantitativo e qualitativo. A pesquisa é do tipo participante, exploratório e descritivo, e foi orientada sob a forma de estudo de caso, com informações anteriores e posteriores à participação dos universitários. A amostra contou com 30 participantes. Foi utilizada a metodologia de análise de conteúdo das respostas. Constatou-se que, por meio da experiência na Assembleia Legislativa, o projeto proporcionou aos estudantes a oportunidade de conhecer a atividade parlamentar, o que possibilitou a compreensão de seu funcionamento
    2016-06Journal article Open access Show more
  • Essays on banking credit acquisition: evidences from SMEs operating in adverse context: collateralization, mutual guarantees and borrowing discouragement
    Publication . Duarte, Fábio Dias; Gama, Ana Paula Bernardino Matias; Esperança, José Paulo Afonso
    This thesis consists in four papers addressing the difficulties of Small and Medium-sized Enterprises (SMEs) when accessing banking finance in a context of high informational asymmetries , during a period of financial crisis and adjustments of the banking capital ratios. A central characteristic of SMEs is their dependence on bank credit for external financing (Degryse and Van Cayseele, 2000). Asymmetric information and agency costs, however, underlie the inadequate financing of these firms. Previous studies show that, due to the lack of information on individual borrowers, banks issue restrictive loan term contracts to reduce their default exposure. Banks can cause the interest rate to become inefficiently high such that worthy firms are driven out of the credit market (Stiglitz and Weiss, 1981). Alternatively, firms with negative net present value projects could obtain financial support in the credit market by taking advantage of cross-subsidization of borrowers with worthy projects (Mankiw, 1986; De Meza and Webb, 1987). In both cases, the reason for market failure is that banks are unable to assess the actual riskiness of SMEs and are forced to offer the same contract to them with a different probability of success. Hence, to overcome screening errors, lenders may reject part of a firm´s loan request (i.e., type I rationing) or simply turn down the credit (i.e., type II rationing) (Steijvers and Voordeckers, 2009a). Recent studies show that when borrowers’ wealth is large enough, banks may bypass informational asymmetries by offering a menu of contracts with collateral requirements which, acting as a sorting device, mitigates the screening errors and the credit rationing for good firms. In this case, risky borrowers will be self-selected by choosing contracts with high repayment (i.e., high interest rates) and low collateral, while safe borrowers will choose contracts with high collateral and low repayment (Han et al., 2009a). Thus, in the design of loan term contracts, collateral assumes a key role as a risk management instrument (Bonfim, 2005). Its role, however, has been little studied in the field of entrepreneurial finance and has been validated, particularly, in the context of a market-based system that gives to SMEs a wider range of funding sources (La Porta et al., 1998). Furthermore, it seems entirely plausible that the role of collateral differs within developed and less developed countries (Menkhoff et al., 2012), surrounded by different levels of informational asymmetries (Hainz, 2003; Beck et al., 2006; Menkhoff et al., 2006), and that their efficiency depends on its nature (i.e., business versus personal collateral – Mann, 1997b). The features of collateral also depend on the characteristics of the individual loan and the firm (Berger and Udell, 1998; Columba et al., 2010) as well as the legal procedures for loan recovery (Zecchini and Ventura, 2009). If SMEs are unable to post collateral while they have a short credit history, meet less rigorous reporting requirements and the availability of public information is scarce (Columba et al., 2010) or if the legal system is inadequate to protect creditor rights (Zecchini and Ventura, 2009), their access to bank credit would remain restricted especially during economic downturns, with negative effects on industry Dynamics competitiveness and growth (Beck and Demirgüc- Kunt, 2006). In this context, in almost half of countries around the world several types of loan guarantee funds have been created to help SMEs to gain easier access to the credit market (Green, 2003; Gonzàles et al., 2006; Beck et al., 2010; Cowling, 2010; Honohan, 2010). The importance of mutual guarantee schemes (MGS) is destined to further increase in the light of the Basel II and III Capital Accords which state that the guarantees of such institutions can, if granted in compliance with some requirements, allow banks to mitigate credit risk with small business lending, and thus, save regulatory capital (SPGM, 2007; Cardone-Riportella et al. 2008). In the recent years, the allocation of mutual guarantees gained a momentum, especially in Organization for Economic Co-operation and Development (OECD) countries. Since the onset of the crisis in the international financial sector, MGS have been the privileged instrument to extend credit for SMEs without compromising the capital requirements of banks (Uesugi et al, 2010). However, the question whether third-party guarantee is an effective instrument to promote lending to SMEs is a controversial issue in both academic and policy literature (Cowling, 2010; Honohan, 2010; Boschi et al., 2014). Traditionally, practitioners and policy makers have been concentrating much of their attention in those firms that apply for bank credit and specifically on the credit rationing problem, marginalizing those firms which do not apply for loans, even when they need external financing. These firms are the so-called “discouraged borrowers” (Cavalluzzo et al., 2002). Although the theoretical model of Kon and Storey (2003) for “discouragement” is, in principle, applicable to both developed and less developed economies, it is expected that discouragement is higher in less developed countries due to lower business traceability (e.g., Chakravarty and Xiang, 2013; Brown et al., 2011; Cole and Dietrich, 2012). Empirical literature on the discouragement problem in less developed countries is, however, limited providing a fertile ground for the study of the causes for the existence of discouraged borrowers. Based on this theoretical and empirical framework, this thesis critically approaches underexplored dimensions of banking lending activity targeted to SMEs financing, such as: the collateralization policy; the role of mutual guarantees; and the discouraged demand for credit. In the first chapter we examine the simultaneous impact of observed characteristics and private information on SMEs´ loan contracts, using data from a major commercial bank operating in Portugal, gathered between January 2007 and December 2010. Using a multiperiod setting, this paper provides the first analysis of the sorting by signalling and self-selection (SBSS) model in a bank-based system. Furthermore, this chapter provides empirical evidence of the effect of macroeconomic conditions on loan contracts during credit crunch and recession periods. Using 12,666 credit approvals, the main results show that borrowers with good credit scores and a high probability of success as they are unlikely to default, are more willing to pledge collateral in return for lower interest rate premium (IRP). In an interactive and sequential event, we confirm that lenders tailor the specific terms of the contract, based on the observable characteristics, increasing both collateral requirements and IRP, for observed risky borrowers, in line with Han et al (2009a)´s SBSS model. However, we reject the positive effect of loan size, predicted by the SBSS model, in terms of loan price negotiation. We argue that loan size decreases the probability of collateralization and the loan interest rates, suggesting that larger loans increase the potential payoff for banks and are assigned to borrowers with good observable characteristics. As loan maturity increases, in contrast, the lender is more likely to demand collateralization and IRP, especially if the borrower is bad or unobservably good, in line with moral hazard arguments (Jensen and Meckling, 1976; Boot et al., 1991). This paper shows that our findings are robust when we predict the degree of collateralization offered by the borrower, adding strength to the SBSS model and contributing to overcome its empirical gaps underlined by Lambrecht (2009). The second chapter scrutinizes the role of mutual guarantees in Portuguese bank lending activity. Using data provided by the same bank, covering 11,181 loans granted to SMEs between January 2008 and December 2010, this paper provides the first appraisal of Portuguese MGS in response to the financial crisis. We examine the characteristics of firms benefiting from mutual guaranteed loans and analyzes the impact of mutual guarantees in loan pricing as well as on the ex-post performance of borrowers. The findings provide a comprehensive insight confirming the value of mutual guarantees to improve Portuguese banking loan activity, especially for good SMEs operating in a stressful context, reducing the costs of borrowing and improving the ex post default of borrowers. Thus, we suggest that mutual guarantees could be used to raise the loan´s recovery rate allowing banks to meet their commitments with banking regulation and supervision in the context of financial crisis. We also argue that these effects are especially noticeable by combining third-party guarantees and collateral. The third chapter extends the empirical evidences on the determinants of the collateral in loan contract terms in countries characterized by low informational traceability and low creditor protection. It uses the fourth-round database of the Business Environment and Enterprise Performance Survey (BEEPS) carried out between 2007 and 2009, covering 3,403 ultimately banking credit approvals for SMEs, operating in Eastern European and Central Asia less developed countries. This paper examines the incidence of business and personal collateral and its level reporting first-hand evidence regarding the impact of the recently reformed credit environment on collateral requirements. The findings endorse the importance in producing and sharing private information between lenders to reduce informational asymmetries and consequently the need to provide collateral to receive a loan. Moreover, we find that market concentration increases banks´ lazy-behavior by asking for collateral not to mitigate observable risk but to reduce screening efforts. We also prove that reforms around the depth of information-sharing instruments by public credit registries only have practical effects mitigating credit constraints and reducing the collateral requirements when coupled with public reforms on its coverage. In addition, this chapter shows that business and personal collateral have distinctive values addressing moral hazard and adverse selection problems, especially relevant in the context under study, advising caution on the practitioners’ extrapolations when modeling the determinants of bank loans collateralization. The fourth chapter examines the conditions that favor the existence of discouraged borrowers, using data provided by the fourth-round of the BEEPS. This paper selects 6,307 loan seekers, among which 2,207 SMEs are typed as discouraged borrowers and 4,280 are classified as loan applicants. We prove that whereas the firm´s opaqueness, demographic issues and distance between borrower and lender better explains the discouragement by tough loan price and/or loan application procedures, the firm´s risk and the banking concentration explains the incidence of discouraged borrowers by fear of rationing. Nonetheless, we argue that in a higher concentrated banking system, those firms with a closer and more intensive relationship with the bank are more likely discouraged to apply for a loan than distant borrowers. This is reasonable if we assume that these firms are more likely to rely on banks as their primordial source of finance, getting locked by the superior bargaining power of the credit provider in a context of low competition (Sharpe, 1991; Detragiache et al. 2000). In turn, this bargaining power may discourage the business to apply for new loans. The innovator status, the legal protection of borrowers and lenders in a default event and the coverage of information sharing instruments help to explain the discouragement in a transversal way.
    2016-06Doctoral thesis Open access Show more
  • Fatores determinantes do desempenho inovador nas empresas portuguesas: cooperação, capacidade de absorção e políticas públicas
    Publication . Coito, Dulcineia Catarina Moura de Sousa; Madeira, Maria José Aguilar
    A inovação tem assumido um papel cada vez mais relevante no panorama económico de atuação das empresas, com notórios resultados no desenvolvimento das regiões e dos países, por força da adaptação às constantes mudanças ditadas pelo cenário da globalização dos mercados. Perante esse panorama de desafios onde, por um lado, se encontram as empresas, cuja atividade exige uma constante aprendizagem a fim de se afirmarem na escala das vantagens competitivas e, por outro lado, os consumidores/utilizadores sempre ávidos de soluções inovadoras, que correspondam ou até mesmo superem as necessidades que emergem, a inovação assume um papel de suma importância para a dinamização da atividade empresarial. Desde Schumpeter até aos mais recentes contributos académicos, o conceito tem vindo a ganhar relevo e constantes atualizações, que têm também permitido alargar o papel da inovação ao ambiente externo das empresas, destacando a importância da atuação em rede e da partilha de conhecimento. Assim sendo, considera-se pertinente a análise dos determinantes do desempenho inovador das empresas, que, no âmbito da presente investigação são: a Cooperação, as Políticas Públicas de estímulo à inovação e a Capacidade de Absorção. Assume-se de importância concetual o conjunto de abordagens que têm vindo a afigurar-se como referencial da temática da inovação, o que conduz a uma base empírica que permite analisar esses determinantes, com recurso aos dados disponíveis do CIS 2010 e à aplicação dos modelos de regressão logística. Os resultados mostram que os determinantes considerados diferem consoante o tipo de inovação – de produto, de processo, organizacional e de marketing. Sendo o tipo de inovação de processo o mais representativo das empresas que compõem a amostra, os resultados indicam que, ao nível das Políticas Públicas, apenas o apoio financeiro proveniente da Administração Central contribui positivamente para o desempenho inovador. O mesmo se verifica no caso de inovações de produto. Já a Cooperação, ao nível da inovação do produto, está positivamente relacionada com o desempenho inovador das empresas, quaisquer que sejam os parceiros de cooperação e as fontes de informação. A Capacidade de Absorção apresenta uma relação positiva com o desempenho inovador, tanto nas inovações organizacionais como nas inovações de marketing. No caso das inovações de processo e de produto, a Capacidade de Absorção está associada apenas ao investimento em atividades de I&D. Quando se trata de inovações organizacionais o tipo de apoio financeiro que apresenta uma relação positiva com o desempenho inovador é o que provém dos fundos comunitários. E o apoio financeiro público de base local/regional está positivamente relacionado com o desempenho inovador no caso de inovações de marketing. Também, os resultados permitem perceber que as inovações de produto do tipo ‘novo para o mercado’ são as mais proeminentes, comparativamente com as inovações ‘novo para a empresa’. A análise empírica possibilitou ainda verificar a relação positiva da Cooperação e da Capacidade de Absorção como determinantes da participação das empresas em iniciativas resultantes da implementação de Políticas Públicas de estímulo à inovação.
    2016-06Doctoral thesis Open access Show more
  • Comportamento humano em caso de incêndio
    Publication . Cordeiro, Elisabete da Cunha; Coelho, António Leça; Nepomuceno, Miguel; Craveiro, João Lutas
    Neste artigo apresenta-se uma breve síntese dos dados obtidos através de 4 inquéritos realizados no âmbito de uma tese de doutoramento com o objetivo de modelar o comportamento da população portuguesa em caso de incêndio, nomeadamente no que se refere a aspetos como, por exemplo, as reações dos ocupantes aos sinais de incêndio e aos sistemas de deteção e alarme automático, as ações que os ocupantes realizam antes de decidirem deixarem o edifício e o pânico.
    2016-06Conference object Open access Show more
  • Hair analysis for alcohol biomarkers: assessing excessive consumption in a student population
    Publication . Oppolzer, David Jerónimo; Gallardo Alba, Maria Eugénia; Barroso, Mário Jorge Dinis; Passarinha, Luís António Paulino
    Alcohol consumption within the student population has become an increasing health concern in several countries. The use of alcohol has deleterious consequences on intellectual performance of students, and can be associated with a variety of risky situations, as injuries, unplanned and unsafe sex, sexual and non-sexual violence, property damage and reckless driving. Monitoring alcohol consumption in the student population is therefore important to identify the degree of the problem and to assess consumption trends, allowing also for the implementation of adequate policies, as well as verifying their effectiveness. Alcohol consumption can be monitored using statistics, such as survey studies performed on the population by means of questionnaires. These approaches have relative efficiency and are widely used; however, considerable limitations are associated to their use, making them unreliable for clinical and/or forensic purposes. Alcohol biomarkers are measurable substances in a biological sample, whose presence indicates some form of exposure to alcohol, and their use to assess alcohol exposure in clinical and forensic scenarios has been applied in a variety of biological specimens in the past years. One of the most notable of these specimens is hair, which presents several advantages, including non-invasive collection, ease of availability, long windows of detection and low chance of adulteration. Hair testing for alcohol exposure relies mainly on the analysis of two biomarkers, ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). These markers have been widely applied in several studies, and were shown to present good sensitivity and specificity. Therefore, the objective of the present work was to evaluate the alcohol consumption on a university student population using two main approaches, one based on questionnaire analysis, and the second on the analytical determination of alcohol biomarkers in hair. A total of 1192 hair samples, and respective self-completion questionnaire were collected, 975 samples were analysed thereof. Through analysis of the questionnaires it was found that alcohol consumption started mostly at the age of 15, and that most of the students considered their consumption as moderate, while almost one-third consumed alcohol excessively at least once in the last month. Beer was reported to be the most consumed beverage, and drinking was widely preferred accompanied. Places for alcohol consumption are mostly public places, such as coffee bars. Higher ingested quantities of alcohol per drinking occasion were associated with the male genre, but both genres presented mean alcohol volumes indicating risky and excessive drinking. The use of other substances was also assessed, including tobacco, which was a habit in one-third of the students. The incidence of the use of illicit substances was similar, and cannabis was the most consumed substance, but mainly on rare occasions. The use of illicit substances was however associated with drinking events in more than 50% of the students. For alcohol biomarker analysis in hair, a method was developed for the analysis of EtG. The compound was extracted from the hair matrix by ultra-sonication with water, clean-up using mixed anion-exchange solid-phase extraction (SPE) and analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). A second method was developed for the analysis of four FAEEs (ethyl myristate, palmitate, oleate and stearate). The compounds were extracted from the hair matrix by incubation with heptane, extracts were cleaned-up with aminopropyl SPE and analysed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Both methods were validated according to guidelines from the Food and Drug Administration (FDA) and International Conference on Harmonization (ICH). Assessed parameters included sensitivity, limits, linearity, precision and accuracy, recovery, stability and matrix effect. The methods were found to be selective, with a limit of quantification of 3 pg/mg for EtG and 30 pg/mg for each of the four FAEEs. Linearity was obtained in the ranges of 3 – 500 pg/mg for EtG and 30 – 5000 pg/mg for FAEEs, and precision and accuracy were found acceptable according to the guidelines. Overall recovery ranged from 74.79% and 97.90%, and processed EtG samples were stable for at least 96h, and FAEEs samples for at least 24h. Matrix effects were evaluated for EtG analysis and were not significant. Higher concentrations of both biomarkers were obtained for the male genre, and at the universities of Beira Interior and Coimbra. Based on hair sample results, individuals were categorized as abstinent, moderate or excessive drinkers, according to cut-off concentrations proposed by the Society of Hair Testing (SoHT) for both biomarkers. These values are 7 pg/mg of EtG, and 0.2 ng/mg (for 0-3 cm segments) or 0.4 ng/mg (for 0-6 cm segments) of FAEEs, to distinguish abstinence from moderate drinking. To distinguish moderate from excessive drinking, a value of 30 pg/mg of EtG, and 0.5 ng/mg (for 0-3 cm segments) or 1.0 ng/mg (for 0-6 cm segments) of FAEEs was used. At the proposed cut-off values, EtG presented good sensitivity (60-81.6%) and specificity (56.3–90.3%), while for FAEEs good specificity was obtained (87.5–100%), but sensitivity varied between 30.5% and 100%. In order to verify if the currently proposed cut-off values are adequate for the studied population, receiver operating characteristic (ROC) analysis was performed, to determine the optimal cut-offs based on the results. Optimal EtG cut-off concentrations were determined to be 7.30 and 29.85 pg/mg, respectively for abstinence and excessive drinking, which are similar to those proposed by the SoHT. For FAEEs, optimal concentrations were 0.185 and 0.378 ng/mg for abstinence, at 0–3 cm and 0–6 cm hair segments, respectively, both similar to the proposed values. At the cut-off for excessive drinking, similar cut-off values were obtained for both lengths (0.817 and 0.889 ng/mg), but these are not similar to the proposed values. However, they confirm that harmonization of the excessive drinking cut-off value for FAEEs can be possible, at a concentration close to 0.8 ng/mg, regardless the length of the hair segment. The use of hair washing products, such as hair conditioner and mask, was found to be associated with lower concentrations of EtG in hair. Cosmetic treatments as bleaching and/or dyeing were associated with the same effect. No effect was associated with the use of hairspray, gel or wax, and for the FAEEs there was no observable effect associated with any of the mentioned products. This demonstrates the importance of documenting the use of hair washing products and cosmetic treatments during sample collection, and the high care that must be taken during result interpretation, considering this information when positivity or negativity for a hair sample is to be given. Both biomarkers correlated with the self-reported consumption habit, while only EtG correlated with the ingested quantities of alcohol per occasion. Inconclusive cases were obtained during combined interpretation of EtG and FAEEs. These cases could mostly be explained by the use of hair products and cosmetic treatments; however, in a number of cases where no simple explanation could be presented, the results of EtG analysis were in agreement with the questionnaire data. This indicates that EtG should be regarded as the first choice in alcohol consumption assessment, while FAEEs should be used to confirm the results from EtG analysis. Only 56.3% of the self-reported abstinent cases could be confirmed by combined analysis of EtG and FAEEs; for moderate drinkers this percentage was 71.6% and for excessive drinkers 60%. Alcohol consumption underestimation or overestimation are assumed as major reasons for this percentages. Combined alcohol biomarker analysis showed that the student population is majorly composed of moderate drinkers (69.39%), followed by abstinent (18.82%) and excessive drinkers (11.69%). Overall, hair analysis for alcohol biomarkers proved to be a powerful tool for the assessment of alcohol consumption in a student population, with considerable advantages. Hair is a sample easy to collect through non-evasive manners, easily stored and the chances of adulteration are low. Therefore, it has good potential to be applied in population studies, especially because it can complete and confirm a great part of the information obtained by questionnaire analysis with added reliability, promoting as such sound and defensible results.
    2016-06Doctoral thesis Open access Show more
  • A estratégia Oceano Azul como proposta de valor: o caso dos ginásios/health clubs portugueses
    Publication . Vieira, Elsa Regina Monteiro; Ferreira, João José de Matos
    Metaforicamente, Kim e Mauborgne (2005) referem que o mercado é constituído por dois oceanos, o vermelho e o azul. O oceano vermelho representa todas as indústrias que existem hoje. O oceano azul considera todas as indústrias que ainda não existem, representa assim, o mercado não explorado, onde se pode criar a procura e onde existem oportunidades de elevado crescimento e rentabilidade. A esta abordagem Kim e Mauborgne (2005) chamam Estratégia Oceano Azul. Esta tese tem como objetivo geral definir uma metodologia de aplicação da estratégia oceano azul. A pertinência deste estudo deve-se à lacuna de estudos empíricos relativamente à aplicação de metodologias da estratégia oceano azul e também à escassez de investigação no domínio da estratégia no setor dos ginásios/health clubs. Desta forma, os objetivos específicos desta tese são: i) identificar as estratégias implementadas pelos ginásios/health club; ii) analisar a relação entre estratégias implementadas e desempenho dos ginásios/health clubs; iii) identificar a proposta de valor atual oferecida pelos ginásios/health clubs a partir das dimensões da qualidade de serviço; iv) averiguar os atributos, a reduzir, a eliminar, a elevar e a criar para atingir uma ideia de negócio estratégia oceano azul; e v) identificar ideias de negócio para ginásios/health clubs a partir das seis opções estratégicas. Para dar resposta a estes objetivos, esta tese apresenta, em primeiro lugar, uma sistematização da literatura no âmbito da estratégia oceano azul, tendo por base uma pesquisa na web of science core collection. De seguida, relaciona-se as estratégias genéricas com o desempenho aplicando um questionário aos gestores dos ginásios. Para obter as estratégias implementadas, utiliza-se a análise fatorial exploratória e a relação entre estratégias e desempenho é obtida através da aplicação da ANOVA. A proposta de valor atual que os ginásios/health clubs, objeto deste estudo, oferecem é obtida a partir das dimensões da qualidade de serviço. Por último, identificam-se os campos de ação da estratégia oceano azul a partir da análise importância-desempenho através da aplicação de um questionário a ex-clientes de um health club. As conclusões evidenciam que os ginásios/health clubs seguem as seguintes estratégias: combinada, de meio termo, liderança pelo custo, foco, diferenciação e qualidade no serviço. Da relação entre estratégias e desempenho evidencia-se a existência de diferenças estatisticamente significativas de desempenho nas diferentes estratégias. A proposta de valor atual dos ginásios/health clubs baseia-se nas seguintes dimensões: competências dos colaboradores, instalações, serviços principais e serviços complementares. Os atributos a elevar, reduzir, manter e eliminar foram obtidos da análise importância-desempenho e por último, são analisadas as seis opções estratégias mencionadas por Kim e Mauborgne (2005) para reconstruir as fronteiras do setor dos ginásios/health clubs. As contribuições deste estudo são: conhecer as estratégias implementadas pelos ginásios/health clubs objeto deste estudo e a sua relação com o desempenho, uma vez que a investigação nesta área é muito residual. Para além disso, a partir das dimensões da qualidade de serviço é possível aferir a proposta de valor oferecida pelos ginásios/health clubs e averiguar os campos de ação a partir da análise importância-desempenho, são estas as metodologias que apoiam os gestores a validar a situação atual e o que poderá ser uma ideia de negócio oceano azul. Quanto a futuras linhas de investigação menciona-se a possibilidade de aferir as estratégias genéricas por outras metodologias e a mensuração do desempenho utilizar indicadores financeiros e não financeiros. A aferição dos fatores chave a partir de outras metodologias e a outros stakeholders pode ser outra linha de investigação a explorar. A aferição dos campos de ação neste estudo foi efetuada a partir dos ex-clientes, no entanto, Kim e Mauborgne (2005) menciona outras categorias de não clientes, desta forma, será útil aplicar às outras categorias. E por último, será útil efetuar um estudo qualitativo através de entrevistas para aferir de forma mais profunda os dados recolhidos de forma quantitativa neste estudo.
    2016-06Doctoral thesis Open access Show more
  • Determinantes do desempenho inovador em Portugal e na Europa
    Publication . Carvalho, João António Marrucho; Madeira, Maria José Aguilar; Carvalho, Luísa Cagica
    No contexto da globalização, onde as crises de natureza financeira, económica, política e/ou social têm originado diversos fenómenos que afetam os indivíduos e as organizações, a inovação assume uma importância relevante, com impacto em todos os setores de atividade e ao nível da sociedade em geral. A inovação é, neste contexto, considerada como um dos fatores chave da competitividade das empresas e das nações. É geralmente aceite que as vantagens competitivas sustentáveis dependem cada vez mais da capacidade de inovação das empresas e, consequentemente, esta terá reflexos no seu desempenho inovador. Desta forma, é necessário um conhecimento mais aprofundado do processo de inovação, incidindo o mesmo, principalmente, no estudo dos fatores que possam influenciar positiva e/ou negativamente o desempenho inovador das empresas. A investigação foi desenvolvida com base em cinco artigos correspondentes a cinco capítulos, sendo que o capítulo 2 apresenta a revisão da literatura e os restantes quatro capítulos a investigação empírica. O objetivo principal consiste na identificação e análise dos principais fatores determinantes que influenciam o desempenho inovador das empresas no produto e no processo. Na revisão da literatura, toma-se como base, as abordagens atuais de referência sobre a temática da inovação, nomeadamente, a sistémica da inovação, a das redes e a de recursos e capacidades, bem como a abordagem da inovação aberta. Para além disso, propõem-se, em cada capítulo, um ou mais modelos concetuais que servem de suporte à análise empírica. Para testar empiricamente as hipóteses formuladas, utilizaram-se dados secundários disponibilizados pelo Gabinete de Planeamento, Estratégia, Avaliação e Relações Internacionais do Ministério da Ciência, Tecnologia e Ensino Superior (GPEARI/MCTES), com a autorização delegada pelo Instituto Nacional de Estatística (INE) e com a supervisão do EUROSTAT, pertencentes ao Inquérito Comunitário à Inovação (Community Innovation Survey) 2010 - CIS 2010, para os capítulos 3, 4 e 5 e ao Community Innovation Survey (microdata CIS) – CIS 2008, no capítulo 6, disponibilizado pelo EUROSTAT. Perante a complexidade do tema em estudo, explicado por múltiplos fatores, tornou-se necessário explorar as relações que os fatores determinantes da inovação selecionados exercem entre si e sobre o desempenho inovador das empresas, no produto e no processo, pelo que se recorreu à análise estatística multivariada. Assim, aos dados obtidos aplicaram-se modelos de regressão logística que permitiram fazer o contraste empírico das hipóteses de investigação relativas aos diversos fatores em estudo em cada um dos capítulos. Os resultados obtidos nos capítulos 3, 4 e 5 mostram, maioritariamente, que os fatores: cooperação, capacidade de absorção, apoio financeiro público, investigados no capitulo 3, barreiras à inovação investigadas no capítulo 4 e, cooperação, capacidade de absorção, apoio financeiro público e barreiras à inovação, investigados no capitulo 5, influenciam positivamente a propensão para a empresa inovar e, consequentemente, o seu desempenho inovador. No capítulo 6 estudou-se a cooperação para a inovação na União Europeia nos 15 países incluídos na microdata CIS 2008, na indústria e serviços, de forma a compreender-se se é possível identificar um padrão de comportamento que pudesse influenciar o desempenho inovador das empresas na Europa. Os resultados obtidos sugerem que a cooperação para a inovação é baixa, em geral, e que existem diferenças entre a indústria e os serviços, o que pode influenciar o desempenho inovador das empresas.
    2016-06Doctoral thesis Open access Show more
  • Particle swarm and Box׳s complex optimization methods to design linear tubular switched reluctance generators for wave energy conversion
    Publication . Mendes, R.P.G.; Calado, M. do Rosário; Mariano, S.
    This paper addresses the optimization of the linear switched reluctance generator with tubular topology to be applied in a sea wave energy conversion system. Two new algorithms to optimize the geometry of the generators are proposed. The algorithms are based on both particle swarm and Box´s complex optimization methods. The optimization procedures consist of a multidimensional optimal value search. First the initial variable vectors are specified throughout the feasible search space. Then, an iterative procedure is applied with the goal of finding the variable values that minimize the objective function. The proposed algorithms are suitable for the optimization problem considered since the objective function is highly nonlinear and not analytically defined, as evaluated using a finite element analysis based software, and show very good performance. A factor that characterizes the generation capabilities is also defined and the obtained optimized generators are compared.
    2016-06Journal article Restricted access Show more