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O preparo da amostra é uma das etapas mais importantes em toda a análise química. O isolamento e a concentração dos componentes da amostra são cruciais e busca-se sempre que essas etapas sejam as mais simples e consumam o mínimo possível de tempo e reagentes. Nos últimos anos, um tipo de material tem se mostrado bastante útil para análises químicas a partir de fluidos biológicos, os polímeros molecularmente impressos (MIPs). Os MIPs são sintetizados por reações de polimerização, na presença de uma molécula molde (template). A molécula molde se liga aos monômeros funcionais do polímero durante a reação de polimerização e permanece ligada à superfície das cadeias poliméricas quando a reação se completa. Terminada a polimerização, realiza-se a completa lavagem das moléculas molde, assim, restam na superfície polimérica cavidades tridimensionais complementares à molécula empregada como molde. Essas cavidades permitem a ligação reversível e preferencial da molécula molde ou outras com estrutura química semelhante. A Cannabis sativa é a droga ilícita mais consumida em todo o mundo e nos últimos anos muita atenção tem se voltado a seus efeitos toxicológicos no corpo humano e a aplicações medicinais. Nesta dissertação, foi sintetizado um MIP com a molécula molde catequina para a extração e posterior análise por LC-MS/MS dos canabinóides Δ9-tetrahidrocanabinol (THC), 11-hidroxi-Δ9-tetrahidrocannabinol (THC-OH) e 11-nor-Δ9-tetrahidrocannabinol-9-ácido carboxílico (THC-COOH) em amostras de urina. O MIP produzido foi empacotado em microdispositivo e empregado no preparo das amostras de urina por microextração por sorvente empacotado (MEPS). O método desenvolvido apresentou boa linearidade (valores de r de 0,977 para o THC e 0,994 para THC-OH e THC-COOH). Os limites de detecção e de quantificação foram respectivamente de 5 ng mL-1 e 20 ng mL-1, para os compostos THC e THC-OH, na faixa linear de 25 a 250 ng mL-1. Para o composto THC-COOH os limites de detecção e quantificação alcançados foram de 1 ng mL-1 e 5 ng mL-1, respectivamente, na faixa linear de 5 a 170 ng mL-1. O método apresentou valores razoáveis de precisão entre 3,2% (THC-COOH) e 25,1% (THC) e de exatidão, que variou entre -18,4 e 17,4 (ambos para o THC). O MIP empregado no preparo da amostra mostrou-se mais seletivo e específico do que materiais normalmente empregados para a extração dos canabinoides das amostras de urina, além de a técnica de extração por MEPS apresentar baixo consumo de solventes e amostra para a extração dos analitos e posterior análise por LC-MS/MS. / The sample preparation is one of the most important steps in every chemical analysis. The isolation and concentration of the sample components are crucial and it is always sought that these steps are simple and consume the lowest amount of time and reagents. In the recent years, a type of material has proved to be very useful for chemical analyzes of biological fluids, the molecularly imprinted polymers (MIPs). MIPs are synthesized by polymerization reactions in the presence of a template molecule. The template molecule binds to the functional monomers of the polymer during the polymerization reaction and remains bonded to the surface of the polymeric chains after the reaction is complete. After the polymerization is finished, the complete washing of the template molecules is carried out, thus, three-dimensional cavities, complementary to the molecule used as a template, remain on the polymer surface. These cavities allow the reversible and preferential bonding of the template molecule or others with similar chemical structure. Cannabis sativa is the most commonly consumed illicit drug in the world and in recent years much attention has focused on its toxicological effects on human body and for medical applications. In this master dissertation, a MIP was synthesized with the catechin molecule as template, for extraction and subsequent analysis by LC-MS/MS of the cannabinoids Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH), and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. The MIP produced was packed in a microdevice and used in the preparation of the urine samples by microextraction by packed sorbent (MEPS). The developed method showed good linearity (r values of 0.977 for THC and 0.994 for THC-OH and THC-COOH). The detection and quantification limits were respectively 5 ng mL-1 and 20 ng mL-1 for THC and THC-OH in the linear range from 25 to 250 ng mL-1. For the compound THC-COOH the limits of detection and quantification achieved were 1 ng mL-1 and 5 ng mL-1, respectively, in the linear range from 5 to 170 ng mL-1. The method presented reasonable values of precision, between 3.2% (for THC-COOH) and 25.1% (for THC) and displayed accuracy ranging from -18.4 to 17.4 (both for THC). The MIP used in the sample preparation was more selective and specific than other materials usually employed for the extraction of the cannabinoids from the urine samples. The MEPS technique also showed low consumption of solvents and sample for sample preparation, extraction of analytes and subsequent analysis by LC-MS/MS.

O uso de técnicas miniaturizadas de preparo de amostra vem se tornando uma tendência cada vez mais crescente em química analítica. Dentre elas o MEPS (Microextraction by a Packed Sorbent) apresenta grande potencial por poder ser acoplado on-line, sem grandes modificações, à cromatografia gasosa e líquida, não necessitando de grande quantidade de tempo para análise e seu cartucho sorvente ser reutilizável. O uso de MEPS, foi mais explorado até o presente momento na análise de fármacos em fluídos biológicos; dessa forma existe um pequeno número de publicações que exploram o uso dessa técnica na determinação de agrotóxicos em matrizes de alimentos. Por esse motivo, o presente trabalho teve como objetivo a avaliação do uso dessa técnica na determinação de seis agrotóxicos utilizados no cultivo da cana-de-açúcar (tebutiurom, carbofurano, atrazina, metribuzim, ametrina e bifentrina) em amostras de garapa. Para o desenvolvimento desse estudo foram verificadas dentre as variáveis pH, força iônica, solvente de eluição e volume do solvente de eluição, quais poderiam afetar o desempenho da técnica em diferentes fases extratoras, empregando nessa etapa de otimização planejamento fatorial fracionário 24-1. As fases avaliadas foram C18 Chromabond e HLB Oasis, assim como sistemas comercialmente disponíveis com as fases C18, C8, SAX, SCX e SIL. Durante essa etapa foi realizado um estudo inicial do uso do grafeno como material sorvente em MEPS, considerando as propriedades que esse material apresenta para atuar como adsorvente em técnicas de preparo de amostra. Contudo, o uso do grafeno apresentou entupimento no cartucho de sorção, problema ainda em avaliação. A fase C18 Chromabond foi a que apresentou os melhores resultados, sendo a escolhida para otimização dos parâmetros envolvidos na etapa de extração por MEPS. Os parâmetros otimizados por planejamento fatorial 23 foram os ciclos de: aspiração da amostra, lavagem e eluição. O método desenvolvido foi validado baseado nos critérios exigidos pelo MAPA e apresentou seletividade, linearidade e os limites de quantificação variaram de 2-10 μg/L. A recuperação foi adequada para todos os analitos (71,7-106,9%), assim como a precisão intra e inter-dia que apresentou coeficientes de variação (CV) menores que 16%. O método desenvolvido foi aplicado em quatro amostras reais de garapa de diferentes regiões. / The use of miniaturized techniques in sample preparation has becoming a growing trend in analytical chemistry. Among these techniques MEPS (Microextraction by a Packed Sorbent) presents a great potential affording on-line coupling, without much modification to gas and liquid chromatography systems, in addition it does not require large analyses time and the sorbent cartridge is reusable. MEPS utilization has been explored mainly for drugs analyses in biological fluids, existing limited number of publications that apply this technique for pesticides analyses in food sample matrix. For this reason the goal of present work was the evaluation of MEPS in the analyses of six pesticides used in sugarcane cultivation (tebuthiuron, carbofuran, atrazine, metribuzine, ametryn and bifenthrin) in sugarcane juice samples. During the method development several variables were evaluated including pH, ionic strength, elution solvent and solvent volume, to determine which ones could affect the technique perform in different sorbent phases. For this optimization step, fractional factorial design 24-1 was utilized. Phases evaluated included C18 Chromabond and HLB Oasis, and also commercially available system containg C18, C8, SAX, SCX e SIL. During this step, it was also carried out an initial study employing graphene in a MEPS system; Tanking into account the properties that this material presents to act as adsorbent in sample preparation techniques. However the graphene showed obstruction problems in the sorption cartridge, whose solution is under way. The phase C18 Chromabond showed better results, and was chosen to MEPS parameters optimization. MEPs parameters optimized by full factorial desing 23 were the following cycles: sample aspiration, washing and elution. The method, was validated based upon the MAPA requirements and showed good selectivity, linearity an quantifications limits ranging from 2-10 μg/L. Recovery was satisfactory for all pesticides (71,7-106,9%), intra- and inter-day precision were satisfactory and showed coefficients of variation (CV) less than 16%. Hence, the developed method was applied to the analysis of four real samples of sugarcane juice obtained from different regions.

O uso de técnicas miniaturizadas de preparo de amostra vem se tornando uma tendência cada vez mais crescente em química analítica. Dentre elas o MEPS (Microextraction by a Packed Sorbent) apresenta grande potencial por poder ser acoplado on-line, sem grandes modificações, à cromatografia gasosa e líquida, não necessitando de grande quantidade de tempo para análise e seu cartucho sorvente ser reutilizável. O uso de MEPS, foi mais explorado até o presente momento na análise de fármacos em fluídos biológicos; dessa forma existe um pequeno número de publicações que exploram o uso dessa técnica na determinação de agrotóxicos em matrizes de alimentos. Por esse motivo, o presente trabalho teve como objetivo a avaliação do uso dessa técnica na determinação de seis agrotóxicos utilizados no cultivo da cana-de-açúcar (tebutiurom, carbofurano, atrazina, metribuzim, ametrina e bifentrina) em amostras de garapa. Para o desenvolvimento desse estudo foram verificadas dentre as variáveis pH, força iônica, solvente de eluição e volume do solvente de eluição, quais poderiam afetar o desempenho da técnica em diferentes fases extratoras, empregando nessa etapa de otimização planejamento fatorial fracionário 24-1. As fases avaliadas foram C18 Chromabond e HLB Oasis, assim como sistemas comercialmente disponíveis com as fases C18, C8, SAX, SCX e SIL. Durante essa etapa foi realizado um estudo inicial do uso do grafeno como material sorvente em MEPS, considerando as propriedades que esse material apresenta para atuar como adsorvente em técnicas de preparo de amostra. Contudo, o uso do grafeno apresentou entupimento no cartucho de sorção, problema ainda em avaliação. A fase C18 Chromabond foi a que apresentou os melhores resultados, sendo a escolhida para otimização dos parâmetros envolvidos na etapa de extração por MEPS. Os parâmetros otimizados por planejamento fatorial 23 foram os ciclos de: aspiração da amostra, lavagem e eluição. O método desenvolvido foi validado baseado nos critérios exigidos pelo MAPA e apresentou seletividade, linearidade e os limites de quantificação variaram de 2-10 μg/L. A recuperação foi adequada para todos os analitos (71,7-106,9%), assim como a precisão intra e inter-dia que apresentou coeficientes de variação (CV) menores que 16%. O método desenvolvido foi aplicado em quatro amostras reais de garapa de diferentes regiões. / The use of miniaturized techniques in sample preparation has becoming a growing trend in analytical chemistry. Among these techniques MEPS (Microextraction by a Packed Sorbent) presents a great potential affording on-line coupling, without much modification to gas and liquid chromatography systems, in addition it does not require large analyses time and the sorbent cartridge is reusable. MEPS utilization has been explored mainly for drugs analyses in biological fluids, existing limited number of publications that apply this technique for pesticides analyses in food sample matrix. For this reason the goal of present work was the evaluation of MEPS in the analyses of six pesticides used in sugarcane cultivation (tebuthiuron, carbofuran, atrazine, metribuzine, ametryn and bifenthrin) in sugarcane juice samples. During the method development several variables were evaluated including pH, ionic strength, elution solvent and solvent volume, to determine which ones could affect the technique perform in different sorbent phases. For this optimization step, fractional factorial design 24-1 was utilized. Phases evaluated included C18 Chromabond and HLB Oasis, and also commercially available system containg C18, C8, SAX, SCX e SIL. During this step, it was also carried out an initial study employing graphene in a MEPS system; Tanking into account the properties that this material presents to act as adsorbent in sample preparation techniques. However the graphene showed obstruction problems in the sorption cartridge, whose solution is under way. The phase C18 Chromabond showed better results, and was chosen to MEPS parameters optimization. MEPs parameters optimized by full factorial desing 23 were the following cycles: sample aspiration, washing and elution. The method, was validated based upon the MAPA requirements and showed good selectivity, linearity an quantifications limits ranging from 2-10 μg/L. Recovery was satisfactory for all pesticides (71,7-106,9%), intra- and inter-day precision were satisfactory and showed coefficients of variation (CV) less than 16%. Hence, the developed method was applied to the analysis of four real samples of sugarcane juice obtained from different regions.

O preparo da amostra é uma das etapas mais importantes em toda a análise química. O isolamento e a concentração dos componentes da amostra são cruciais e busca-se sempre que essas etapas sejam as mais simples e consumam o mínimo possível de tempo e reagentes. Nos últimos anos, um tipo de material tem se mostrado bastante útil para análises químicas a partir de fluidos biológicos, os polímeros molecularmente impressos (MIPs). Os MIPs são sintetizados por reações de polimerização, na presença de uma molécula molde (template). A molécula molde se liga aos monômeros funcionais do polímero durante a reação de polimerização e permanece ligada à superfície das cadeias poliméricas quando a reação se completa. Terminada a polimerização, realiza-se a completa lavagem das moléculas molde, assim, restam na superfície polimérica cavidades tridimensionais complementares à molécula empregada como molde. Essas cavidades permitem a ligação reversível e preferencial da molécula molde ou outras com estrutura química semelhante. A Cannabis sativa é a droga ilícita mais consumida em todo o mundo e nos últimos anos muita atenção tem se voltado a seus efeitos toxicológicos no corpo humano e a aplicações medicinais. Nesta dissertação, foi sintetizado um MIP com a molécula molde catequina para a extração e posterior análise por LC-MS/MS dos canabinóides Δ9-tetrahidrocanabinol (THC), 11-hidroxi-Δ9-tetrahidrocannabinol (THC-OH) e 11-nor-Δ9-tetrahidrocannabinol-9-ácido carboxílico (THC-COOH) em amostras de urina. O MIP produzido foi empacotado em microdispositivo e empregado no preparo das amostras de urina por microextração por sorvente empacotado (MEPS). O método desenvolvido apresentou boa linearidade (valores de r de 0,977 para o THC e 0,994 para THC-OH e THC-COOH). Os limites de detecção e de quantificação foram respectivamente de 5 ng mL-1 e 20 ng mL-1, para os compostos THC e THC-OH, na faixa linear de 25 a 250 ng mL-1. Para o composto THC-COOH os limites de detecção e quantificação alcançados foram de 1 ng mL-1 e 5 ng mL-1, respectivamente, na faixa linear de 5 a 170 ng mL-1. O método apresentou valores razoáveis de precisão entre 3,2% (THC-COOH) e 25,1% (THC) e de exatidão, que variou entre -18,4 e 17,4 (ambos para o THC). O MIP empregado no preparo da amostra mostrou-se mais seletivo e específico do que materiais normalmente empregados para a extração dos canabinoides das amostras de urina, além de a técnica de extração por MEPS apresentar baixo consumo de solventes e amostra para a extração dos analitos e posterior análise por LC-MS/MS. / The sample preparation is one of the most important steps in every chemical analysis. The isolation and concentration of the sample components are crucial and it is always sought that these steps are simple and consume the lowest amount of time and reagents. In the recent years, a type of material has proved to be very useful for chemical analyzes of biological fluids, the molecularly imprinted polymers (MIPs). MIPs are synthesized by polymerization reactions in the presence of a template molecule. The template molecule binds to the functional monomers of the polymer during the polymerization reaction and remains bonded to the surface of the polymeric chains after the reaction is complete. After the polymerization is finished, the complete washing of the template molecules is carried out, thus, three-dimensional cavities, complementary to the molecule used as a template, remain on the polymer surface. These cavities allow the reversible and preferential bonding of the template molecule or others with similar chemical structure. Cannabis sativa is the most commonly consumed illicit drug in the world and in recent years much attention has focused on its toxicological effects on human body and for medical applications. In this master dissertation, a MIP was synthesized with the catechin molecule as template, for extraction and subsequent analysis by LC-MS/MS of the cannabinoids Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH), and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. The MIP produced was packed in a microdevice and used in the preparation of the urine samples by microextraction by packed sorbent (MEPS). The developed method showed good linearity (r values of 0.977 for THC and 0.994 for THC-OH and THC-COOH). The detection and quantification limits were respectively 5 ng mL-1 and 20 ng mL-1 for THC and THC-OH in the linear range from 25 to 250 ng mL-1. For the compound THC-COOH the limits of detection and quantification achieved were 1 ng mL-1 and 5 ng mL-1, respectively, in the linear range from 5 to 170 ng mL-1. The method presented reasonable values of precision, between 3.2% (for THC-COOH) and 25.1% (for THC) and displayed accuracy ranging from -18.4 to 17.4 (both for THC). The MIP used in the sample preparation was more selective and specific than other materials usually employed for the extraction of the cannabinoids from the urine samples. The MEPS technique also showed low consumption of solvents and sample for sample preparation, extraction of analytes and subsequent analysis by LC-MS/MS.

<div> <div> <div> <p>Medication non-adherence and non-compliance left unaddressed can compound into severe medical problems for patients. Identifying patients that are likely to become non-adherent can help reduce these problems. Despite these benefits, monitoring adherence at scale is cost-prohibitive. Social forums offer an easily accessible, affordable, and timely alternative to the traditional methods based on claims data. This study investigates the potential of medication adherence prediction based on social forum data for diabetes and fibromyalgia therapies by using transfer learning from the Medical Expenditure Panel Survey (MEPS). </p><p><br></p> <p>Predictive adherence models are developed by using both survey and social forums data and different random forest (RF) techniques. The first of these implementations uses binned inputs from k-means clustering. The second technique is based on ternary trees instead of the widely used binary decision trees. These techniques are able to handle missing data, a prevalent characteristic of social forums data. </p><p><br></p> <p>The results of this study show that transfer learning between survey models and social forum models is possible. Using MEPS survey data and the techniques listed above to derive RF models, less than 5% difference in accuracy was observed between the MEPS test dataset and the social forum test dataset. Along with these RF techniques, another RF implementation with imputed means for the missing values was developed and shown to predict adherence for social forum patients with an accuracy >70%. </p> </div> </div> <div> <div> <p><br></p> </div> </div> </div> <div> <div> <div> <p>This thesis shows that a model trained with verified survey data can be used to complement traditional medical adherence models by predicting adherence from unverified, self-reported data in a dynamic and timely manner. Furthermore, this model provides a method for discovering objective insights from subjective social reports. Additional investigation is needed to improve the prediction accuracy of the proposed model and to assess biases that may be inherent to self-reported adherence measures in social health networks. </p> </div> </div> </div>

China is the world’s largest producer and consumer of household appliances, lighting and commercial equipment. China first adopted Minimum Energy Performance Standards (MEPS) in 1989. By 2013, China has developed and implemented 52 Energy Efficiency Standards (EES) and 28 mandatory energy labels for a wide range of domestic, commercial, and selected industrial equipment. However, despite of the large number of standards issued, big challenges remain with how to ensure the standards keep up with the dynamic evolvement of technologies and appliance market after they enter effect. The current policy analysis methods adopted by the policy makers primarily focuses on standards making process and very limited attentions were paid on impact assessment and ex-post evaluation of standards and labeling systems, hence the effectiveness of active Energy Efficiency Standards has not been assessed timely and comprehensively. One major barrier of this is the lacking of assessment methods and market data. This thesis intends to tackle the above issues by developing a new policy analysis approach that can be used to assess the impact of energy efficiency standards and labeling with market data. This approach adopts a comprehensive analysis method that comprises three components: (1) Analysis of market data; (2) Quantification of energy savings potential; and (3) Benchmarking China’s EE standards to those of peer economies around the world. This integrated approach leads to three independent but complementary studies that provide evidence-based findings and policy recommendations for the improvement of China’s appliance standards.

The transformation of the world economy that brought the collapse of borders and trade barriers brought a setting conducive to the prosperity of large corporations, while small and medium enterprises have gained additional difficulties to remain in operation. However, with the emergence of collaborative networks of small and medium enterprises through its membership in collaborative networks had the opportunity to reposition itself to face this new scenario. Particularly, the neighborhood grocery, which falls within that context might get to compete against the big hypermarket chains that have proliferated in this environment. With this thesis developed, it was through a case study to identify the factors of competitiveness achieved by a network of supermarkets in operation for over 10 years in local market. Were observed and pointed out the factors that pushed the network over the years of operation and points that deserve more attention and treatment to eliminate potential points of disruption in the operation and that can be improved and provide assistance to each of the network and associated companies hence the network itself. / A transformação da economia mundial, que trouxe a queda das barreiras e fronteiras comerciais, apresenta um cenário propício para a prosperidade das grandes corporações, enquanto, as pequenas e médias empresas ganharam dificuldades adicionais para se manter em operação. Entretanto, com o surgimento das redes de cooperação, as pequenas e médias empresas, através da sua associação em redes de cooperação, tiveram a oportunidade de se reposicionar frente a esse novo cenário. Particularmente, os supermercados de bairros, que se inserem nesse contexto, puderam adquirir condições de competividade frente às grandes cadeias de hipermercados que proliferaram neste ambiente. Com essa dissertação desenvolvida, procurou-se, através de um estudo de caso, identificar quais os fatores de competitividade alcançados por uma rede de supermercados em operação há mais 10 anos no mercado local. Foram observados e apontados os fatores que impulsionaram a rede ao longo desses anos de operação e os temas que merecem maior atenção e tratamento para eliminar possíveis pontos de ruptura na operação. Também assuntos que podem ser melhorados e trazer contribuição a cada uma das empresas associadas à rede e consequentemente à própria rede.

Cette étude comporte deux parties, la première concerne l'analyse des arômes et des flavonoïdes sur deux fruits insulaires et la deuxième est consacrée à l'étude du risque encouru par le personnel intervenant lors d'un feu de forêt. Ces deux thèmes correspondent à une attente au niveau des différents protagonistes et s'inscrivent dans le cadre de différents projets auquel le laboratoire est associé. La première partie concerne l'analyse des composés volatils et des flavonoïdes d'un hybride du genre Citrus ainsi que des baies du myrte commun. En Corse, la production annuelle des clémentines est importante, elle constitue le premier produit d'exportation ; les baies du myrte sont utilisées dans l'élaboration des liqueurs et des vins. Ces deux fruits constituent une dynamique économique importante dans l'île. Les arômes sont des substances responsables des propriétés organoleptiques d'une denrée alimentaire. Nous avons identifiés 44 composés volatils dans les jus de clémentine, de mandarine et des hybrides. Les molécules les plus abondantes sont les monoterpènes hydrocarbonés dont principalement le limonène et le -terpinène. Les flavonoïdes sont des substances à fort potentiel antioxydant, nous avons déterminé deux flavones polyméthoxylées et trois flavanones glycosides. Les baies du myrte sont caractérisées par 36 composés volatils avec majoritairement de l'-pinène, de l'eucalyptol, du cis hex-3-èn-1-ol et par 14 composés phénoliques parmi lesquels, la myricétine et ses dérivés glycosides sont les plus abondants. La deuxième partie présente une autre préoccupation de l'île durant la saison estivale, il s'agit des feux de forêt. Chaque année, des milliers d'hectares de forêt brûlent en Europe et plus précisément dans le bassin méditerranéen. L'observation des phénomènes d'embrasement généralisé a été reportée mais le mécanisme reste mal défini. Le but de ce travail est de connaître les molécules terpéniques émises par cinq végétaux représentatifs du couvert végétal Corse à savoir le pin laricio et le pin maritime, le ciste de Montpellier, la bruyère arborescente et l'arbousier. Il s'agit dans un premier de temps de valider la possibilité d'une inflammation subite d'une poche de gaz de composés organiques volatils biogéniques (COVb). Les analyses réalisées montrent que l'-pinène est le composé majoritaire dans les pins, ce sont les diterpènes qui sont les plus émis par le ciste de Montpellier. Ensuite, nous nous sommes intéressés aux émissions de polluants dues aux feux de végétation et à leur pouvoir toxique sur le personnel intervenant. Pour cela, nous analysons les molécules présentes dans les fumées et nous dosons les BTEX (benzène, toluène, éthylbenzène et xylènes) puis nous les comparons aux valeurs limites d'exposition (VLE). Nous avons démontré que la concentration en benzène est supérieure à la VLE, les pompiers seraient donc exposés à un environnement toxique.

This dissertation explores political representation and its manifestation within the European Union (EU). The main purpose is to examine the representative roles of Members of the European Parliament (MEP) in the context of cross–pressure between the national level and the EU level. This involves an analysis of how the MEPs under-stand their roles, how they organize their work, and how they have voted in the European Parliament (EP) in 1999-2002. It also includes a study of how national party organizations adapt to the EU environment and how this influences the MEPs link to the national arena. The study is based on various sources, such as interviews, formal documents and voting data. The most under-researched part of the cross-pressure has been the national link and the empirical focus of the thesis is on that link. It is a comparative study of parties in Ireland, the Netherlands and Sweden. In each country, three parties were selected (social democratic, right-wing and green parties). By using a focused comparative method, and by controlling for certain independent variables, the ambition is to go beyond description and identify explanations for why MEPs adopt certain roles. The overall picture that emerges is of a relatively weak link between MEPs and the national level. To a certain extent, MEPs express frustration over their limited role in the national arena and over the lack of input from the national arena in their work at the European level. Most of the parties struggle to include MEPs in their organizational set-up, and the MEPs experience a growing hostility within the parties toward them. In general, the lack of interest and knowledge in the national arena, concerning the EU in general and specifically the work of the MEPs, obscures the role of the MEPs. They become EU ambassadors at the national level, rather than elected representatives at the EU level. The dissertation also tests variables that are thought to influence MEPs’ roles: the type of electoral system, popular opinion on EU issues, whether their party is in government, the party’s ideological heritage, and if the party organizes more advanced coordination mechanisms. The main result is that the working assumption that MEPs are influenced by characteristics in the national arena is shown to be largely correct. That is, some of the identified aspects of the national political context do influence how the MEPs understand their roles. For example, the character of the electoral system influences attitudes among the MEPs. However, that relationship is not as simple and straightforward as much of the literature suggests. Rather, the results in this study suggest that the most important aspect of the relationship between the national level and the MEPs is whether parties or others (such as national parliamentarians) actively engage in the work of the MEPs. It matters how parties design the relationship between the levels, especially for how and where MEPs direct their main attention, but also in terms of how MEPs vote in the EP. The conclusion emphasizes the importance of further research into how parties facilitate the link between the national and the EU level.