Depuis ces dernières années, il y a eu augmentation de l'effort pour le développement des systèmes microfluidiques dédiésà la dispersion d'une phase fluide dans une autre phase fluide immiscible. Les gouttelettes ou les bulles résultantes ont de nombreuses applications dans des diverses domaines (photonique, chimique, biologique...). Pour la plupart de ces applications, il est primordial de contrôler la taille et la forme de ces gouttelettes/bulles, paramètres qui influencent directement le comportement ou la réponse du système. Notre but consiste ainsi à générer des gouttelettes de taille unique (mono-dispersées) et contrôlable pour produire des structures accordables. Nous analysons aussi leurs mécanismes de formation et étudions les paramètres qui influent sur leur taille et leur forme. Dans le présent travail, la génération de gouttelettes est réalisée en utilisant une intersection entre deux microcanaux (jonction en T) où leur taille est directement liée à la géométrie. Dans cette configuration, il existe trois régimes connus de génération de gouttelettes qui sont les régimes de dripping, squeezing et jetting. Nous nous sommes particulièrement intéressés à l'étude du régime dripping car il assure la génération de gouttelettes ayant une taille plus petite que celle obtenue avec les autres régimes. Les expériences et les études théoriques ont montré que le diamètre des gouttelettes diminue quand la largeur des canaux diminue, quand la vitesse de la phase continue augmente et quand la vitesse de la phase dispersée diminue. De plus, nous avons pu mettre en évidence un nouveau régime de génération de gouttelettes pour lequel les gouttelettes générées ont un diamètre constant, indépendamment des vitesses des phases continue et dispersée, et qui ne dépend que de la géométrie des canaux. Nous avons appelé ce nouveau régime le régime "balloon". Nous avons enfin montré l'intérêt de l'accordabilité des systèmes microfluidiques en optique et en acoustique. Ainsi, nous avons montré que la période du réseau de diffraction optique est facilement modifiable en contrôlant les paramètres de génération de bulles. De même, nous avons pu voir que la réponse acoustique est liée 'a la résonance des bulles dans le milieu liquide. Cette réponse est une fonction du diamètre des bulles générées. Enfin, nous proposons l'utilisation du système microfluidique en électronique pour produire des capacités variables, ouvrant la voie à des nouvelles fonctionnalités pour la microfluidique diphasique.

L'objectif de cette étude est de concevoir et caractériser une plate-forme micro-fluidique permettant la concentration et la séparation d'un produit de dégradation du trinitrotoluène :l'ortho-nitrotoluène (ONT) considéré comme un traceur de composés explosifs. Les capteurs àbase de dioxyde d'étain (SnO2) utilisés ici comme détecteurs présentent un réel manque desélectivité et leur sensibilité peut s'avérer insuffisante pour la détection de traces de polluantsdans l'atmosphère. L'approche originale envisagée dans cette étude consiste à travailler en amontdu capteur chimique (SnO2), en particulier, en développant d'une part un micro-préconcentrateurde gaz afin d'améliorer l'aspect sensibilité et d'autre part une micro-colonne chromatographiquepour s'affranchir du manque de sélectivité.Dans un premier temps, une série d'adsorbants ont été étudiés et caractérisés pour laconcentration de l'ONT. Les résultats obtenus ont permis de sélectionner trois types de charbonsactifs (N, KL2 et KL3) et une zéolithe hydrophobe DAY.Ensuite, les micro-systèmes fluidiques ont été réalisés sur un substrat de silicium et élaborés enutilisant la technologie silicium/verre.La dernière partie de ce travail est consacrée à l'évaluation des performances d'analyse de cetteplate-forme en termes de concentration et de séparation de l'ONT. En particulier, après avoirévalué les conditions optimales de concentration et d'élution de l'ortho-nitrotoluène, le couplageentre la plate-forme micro-fluidique et le capteur à base de dioxyde d'étain a permis d'une part demontrer que la limite de détection de l'ortho-nitrotoluène est inférieure à 365 ppb. Dans ce cas,une désorption totale de la molécule cible et un facteur de concentration constant ont été obtenusavec la zéolithe DAY. D'autre part, l'utilisation de ce type de plate-forme a permis d'obtenir unebonne performance de détection et de séparation de l'ONT en présence d'un interférent (toluène)et d'un taux d'hygrométrie élevé.

Esta pesquisa visa analisar a política de apoio e de fomento as Micro e Pequenas Empresas no estado de Mato Grosso do Sul, tendo como referência a atuação do SEBRAE/MS no período de 1990 a 2008, através da percepção dos empresários analisados. A pesquisa parte da informação de que o índice de mortalidade das pequenas e micro empresas é de 56% antes de completarem cinco anos de atividades (SEBRAE, 2007). Trata-se de uma informação preocupante, pois, segundo o SEBRAE (2007), as Micro e Pequenas Empresas constituem 99% do número de empresas formalmente estabelecidas no país, responsável por 60% dos empregos gerados, contribuindo com mais de 50% dos salários, e por 20% de participação no Produto Interno Bruto do país. A questão principal a ser investigada é se estas políticas acontecem de forma eficiente e quais as ações tomadas por estas empresas para se manterem no mercado. Para identificar a percepção dos micro e pequenos empresários sobre a contribuição das políticas de apoio e de fomento do SEBRAE/MS, assim como, suas ações tomadas diante das dificuldades enfrentadas, foram realizadas entrevistas e questionários dirigidos a várias empresas. Foi detectado que apenas uma das 24 empresas que aceitaram em participar da pesquisa, demonstrou estar satisfeita com os serviços prestados pelo SEBRAE/MS. Das 24 empresas analisadas, 14 utilizam ou já utilizaram os serviços do SEBRAE/MS e outras 10, não utilizaram. A metodologia utilizada foi de caráter exploratório, com abordagem qualitativa, utilizando a técnica de análise de discurso. Com base nas teorias utilizadas e nas informações obtidas das entrevistas e questionários, a pesquisa evidenciou que esta insatisfação não é proveniente da existência de alguma ineficiência do SEBRAE/MS, relacionado à falta de conhecimento técnico, e sim, da dificuldade do SEBRAE/MS em atender a ansiedade dos empresários pesquisados em obter respostas prontas e imediatas diante das dificuldades que enfrentam. Isto acontece devido à variedade e o volume de atividades existentes dentro destas empresas, mesmo de micro e pequeno porte, que induzem o micro e pequeno empresário ter uma organização e controle não muito eficiente de sua empresa. Quanto mais organizada e controlada, maior a possibilidade de uma empresa deste porte conseguir definir e melhor aproveitar os serviços de apoio e de fomento do SEBRAE/MS em comparação com aquelas cuja organização e controle são deficientes. / This research aims to analyze the political support and encouragement Micro and Small Enterprises in the state of Mato Grosso do Sul, with reference to the performance of SEBRAE / MS in the period 1990 to 2008, through the perception of entrepreneurs analyzed. The research is part of the important information that the mortality rate of small and micro enterprises is 56% before reaching five years of activities (SEBRAE, 2007). It is a troubling information because, according SEBRAE (2007), the Micro and Small Enterprises constitute 99% of the number of companies formally established in the country, accounting for 60% of jobs, contributing over 50% of salaries , and 20% share of the GDP of the country. The main question to be investigated is whether these policies occur efficiently and that the actions taken by these companies to stay in the market. To identify the perceptions of micro and small entrepreneurs on the contribution of political support and encouragement of SEBRAE / MS, as well as their actions taken in the face of difficulties, we conducted interviews and questionnaires to various companies. It was found that only one of 24 companies that agreed to participate in the study, proved to be satisfied with the services provided by SEBRAE / MS. Of the 24 companies surveyed, 14 use or have used the services of SEBRAE / MS and 10 others, did not. The methodology was exploratory in nature, with a qualitative approach, using the technique of discourse analysis. Based on the theories used and the information obtained from interviews and questionnaires, the survey showed that this dissatisfaction is not from the existence of some inefficiency SEBRAE / MS, related to lack of technical knowledge, but rather the difficulty of SEBRAE / MS address the anxiety of businessmen surveyed in getting immediate answers and the difficulties you face. This is due to the variety and volume of existing activities within these businesses, even micro and small, which leads to micro and small business to have an organization and not very efficient control of your company. The more organized and controlled, the greater the possibility of a company this size get set and enjoy the best support services and promotion of SEBRAE / MS compared with those whose organization and control are disabled.

L’aéroacoustique est une filière de l'acoustique qui étudie la génération de bruit par un mouvement fluidique turbulent ou par les forces aérodynamiques qui interagissent avec les surfaces. Ce secteur en pleine croissance a attiré des intérêts récents en raison de l’évolution de la transportation aérienne, terrestre et spatiale. Les microphones avec une bande passante de plusieurs centaines de kHz et une plage dynamique couvrant de 40Pa à 4 kPa sont nécessaires pour les mesures aéroacoustiques. Dans cette thèse, deux microphones MEMS de type piézorésistif à base de silicium polycristallin (poly-Si) latéralement cristallisé par l’induction métallique (MILC) sont conçus et fabriqués en utilisant respectivement les techniques de microfabrication de surface et de volume. Ces microphones sont calibrés à l'aide d'une source d’onde de choc (N-wave) générée par une étincelle électrique. Pour l'échantillon fabriqué par le micro-usinage de surface, la sensibilité statique mesurée est 0.4μV/V/Pa, la sensibilité dynamique est 0.033μV/V/Pa et la plage fréquentielle couvre à partir de 100 kHz avec une fréquence du premier mode de résonance à 400kHz. Pour l'échantillon fabriqué par le micro-usinage de volume, la sensibilité statique mesurée est 0.28μV/V/Pa, la sensibilité dynamique est 0.33μV/V/Pa et la plage fréquentielle couvre à partir de 6 kHz avec une fréquence du premier mode de résonance à 715kHz. / Aero-acoustics, a branch of acoustics which studies noise generation via either turbulent fluid motion or aerodynamic forces interacting with surfaces, is a growing area and has received fresh emphasis due to advances in air, ground and space transportation. Microphones with a bandwidth of several hundreds of kHz and a dynamic range covering 40Pa to 4kPa are needed for aero-acoustic measurements. In this thesis, two metal-induced-lateral-crystallized (MILC) polycrystalline silicon (poly-Si) based piezoresistive type MEMS microphones are designed and fabricated using surface micromachining and bulk micromachining techniques, respectively. These microphones are calibrated using an electrical spark generated shockwave (N-wave) source. For the surface micromachined sample, the measured static sensitivity is 0.4μV/V/Pa, dynamic sensitivity is 0.033μV/V/Pa and the frequency range starts from 100kHz with a first mode resonant frequency of 400kHz. For the bulk micromachined sample, the measured static sensitivity is 0.28μV/V/Pa, dynamic sensitivity is 0.33μV/V/Pa and the frequency range starts from 6kHz with a first mode resonant frequency of 715kHz.

Depuis quelques années, investir dans le secteur agricole est devenu un des objectifs prioritaires des politiques économiques de lutte contre la pauvreté en Afrique Subsaharienne. Or, dans la perspective des Objectifs du Millénaire pour le Développement, les pays doivent également faire face à la nécessité croissante d’orienter leurs ressources budgétaires limitées vers le financement de leurs dépenses sociales. Dans ce contexte, en prenant appui sur le cas spécifique de l’Ouganda, l’objectif de cette thèse est de savoir dans quelle mesure il est possible de concilier simultanément ces impératifs sociaux et économiques en exploitant les effets de croissance de certaines dépenses sociales dans la sphère agricole. La santé des ménages agricoles joue alors le rôle de variable stratégique de l’analyse parce qu’elle est à la fois une dimension du bien être dont sont privés les plus pauvres et parce qu’elle détermine également leur niveau de productivité. Dans un premier temps, les facteurs socioéconomiques qui influencent la dépense en santé des Ougandais ont été identifiés. Ils révèlent la complexité de ce processus de dépense, ses relations avec la morbidité et le choix du type de fournisseurs de soins ou les interdépendances entre les différentes catégories de dépenses en soins. Dans un deuxième temps, l’analyse porte une seconde composante essentielle de la santé : la diversité alimentaire. Elle révèle une hétérogénéité inobservée a priori entre les ménages ougandais ainsi que les principaux déterminants socio-économiques de leur demande de diversité alimentaire. Dans un troisième temps, l’accent est mis sur la nature et l’intensité du lien entre les différentes catégories de dépense en santé et la productivité des agriculteurs ougandais. Enfin, une partie de ces résultats micro-économétriques est replacée dans un cadre d’Equilibre Général pour simuler les impacts macroéconomiques et microéconomiques d’une subvention publique du prix des produits de santé non marchands en Ouganda. Les résultats obtenus montrent alors qu’il semble possible de mener dans ce pays des politiques répondant simultanément aux besoins sociaux de court terme de la population et aux impératifs économiques de plus long terme de croissance pro-pauvres, et d’en maximiser les effets à moindre coût en ciblant certains types de ménages et/ou certains types de services de santé. / In recent years, investment in agriculture has become one of the priority objectives of economic policies to fight against poverty in Sub-Saharan Africa. However, from the perspective of Millennium Development Goals, African countries must also deal with the increasing need to focus their scarce budgetary resources towards social spending. In this context, taking the specific case of Uganda, the objective of this thesis is to understand how it is possible to simultaneously achieve these social and economic goals by exploiting the growth effects of some social spending in the agricultural sector. Farmers ‘health plays a critical role of the analysis because it is both a dimension of well-being which are denied to the poor and a determinant of their productivity. At first, socio-economic factors that influence health spending of Ugandans have been identified. They reveal the complexity of this expenditure process, its relationship with morbidity and the choice of healthcare providers, or the interdependencies between the different types of healthcare expenditures. Next, the analysis focuses on a second essential component of health: food diversity. It reveals an a priori unobserved heterogeneity between Ugandan households and the main socio-economic determinants of their demand for food diversity. In a third step, emphasis is placed on the nature and intensity of the link between the different categories of health expenditure and the productivity of Ugandan farmers. Lastly, some of these previous micro-econometric results are replaced in a general equilibrium framework to simulate the macroeconomic and microeconomic impacts of government subsidies on health in Uganda. Results show that it seems possible to design policy in this country which meets simultaneously the short-term social needs of population and the longer-term economic imperatives of pro-poor growth. They also show that it is possible to maximize the effects of these policies at lower cost by targeting certain types of households and / or certain types of health services.

Esta pesquisa visa analisar a política de apoio e de fomento as Micro e Pequenas Empresas no estado de Mato Grosso do Sul, tendo como referência a atuação do SEBRAE/MS no período de 1990 a 2008, através da percepção dos empresários analisados. A pesquisa parte da informação de que o índice de mortalidade das pequenas e micro empresas é de 56% antes de completarem cinco anos de atividades (SEBRAE, 2007). Trata-se de uma informação preocupante, pois, segundo o SEBRAE (2007), as Micro e Pequenas Empresas constituem 99% do número de empresas formalmente estabelecidas no país, responsável por 60% dos empregos gerados, contribuindo com mais de 50% dos salários, e por 20% de participação no Produto Interno Bruto do país. A questão principal a ser investigada é se estas políticas acontecem de forma eficiente e quais as ações tomadas por estas empresas para se manterem no mercado. Para identificar a percepção dos micro e pequenos empresários sobre a contribuição das políticas de apoio e de fomento do SEBRAE/MS, assim como, suas ações tomadas diante das dificuldades enfrentadas, foram realizadas entrevistas e questionários dirigidos a várias empresas. Foi detectado que apenas uma das 24 empresas que aceitaram em participar da pesquisa, demonstrou estar satisfeita com os serviços prestados pelo SEBRAE/MS. Das 24 empresas analisadas, 14 utilizam ou já utilizaram os serviços do SEBRAE/MS e outras 10, não utilizaram. A metodologia utilizada foi de caráter exploratório, com abordagem qualitativa, utilizando a técnica de análise de discurso. Com base nas teorias utilizadas e nas informações obtidas das entrevistas e questionários, a pesquisa evidenciou que esta insatisfação não é proveniente da existência de alguma ineficiência do SEBRAE/MS, relacionado à falta de conhecimento técnico, e sim, da dificuldade do SEBRAE/MS em atender a ansiedade dos empresários pesquisados em obter respostas prontas e imediatas diante das dificuldades que enfrentam. Isto acontece devido à variedade e o volume de atividades existentes dentro destas empresas, mesmo de micro e pequeno porte, que induzem o micro e pequeno empresário ter uma organização e controle não muito eficiente de sua empresa. Quanto mais organizada e controlada, maior a possibilidade de uma empresa deste porte conseguir definir e melhor aproveitar os serviços de apoio e de fomento do SEBRAE/MS em comparação com aquelas cuja organização e controle são deficientes. / This research aims to analyze the political support and encouragement Micro and Small Enterprises in the state of Mato Grosso do Sul, with reference to the performance of SEBRAE / MS in the period 1990 to 2008, through the perception of entrepreneurs analyzed. The research is part of the important information that the mortality rate of small and micro enterprises is 56% before reaching five years of activities (SEBRAE, 2007). It is a troubling information because, according SEBRAE (2007), the Micro and Small Enterprises constitute 99% of the number of companies formally established in the country, accounting for 60% of jobs, contributing over 50% of salaries , and 20% share of the GDP of the country. The main question to be investigated is whether these policies occur efficiently and that the actions taken by these companies to stay in the market. To identify the perceptions of micro and small entrepreneurs on the contribution of political support and encouragement of SEBRAE / MS, as well as their actions taken in the face of difficulties, we conducted interviews and questionnaires to various companies. It was found that only one of 24 companies that agreed to participate in the study, proved to be satisfied with the services provided by SEBRAE / MS. Of the 24 companies surveyed, 14 use or have used the services of SEBRAE / MS and 10 others, did not. The methodology was exploratory in nature, with a qualitative approach, using the technique of discourse analysis. Based on the theories used and the information obtained from interviews and questionnaires, the survey showed that this dissatisfaction is not from the existence of some inefficiency SEBRAE / MS, related to lack of technical knowledge, but rather the difficulty of SEBRAE / MS address the anxiety of businessmen surveyed in getting immediate answers and the difficulties you face. This is due to the variety and volume of existing activities within these businesses, even micro and small, which leads to micro and small business to have an organization and not very efficient control of your company. The more organized and controlled, the greater the possibility of a company this size get set and enjoy the best support services and promotion of SEBRAE / MS compared with those whose organization and control are disabled.

Esta pesquisa visa analisar a política de apoio e de fomento as Micro e Pequenas Empresas no estado de Mato Grosso do Sul, tendo como referência a atuação do SEBRAE/MS no período de 1990 a 2008, através da percepção dos empresários analisados. A pesquisa parte da informação de que o índice de mortalidade das pequenas e micro empresas é de 56% antes de completarem cinco anos de atividades (SEBRAE, 2007). Trata-se de uma informação preocupante, pois, segundo o SEBRAE (2007), as Micro e Pequenas Empresas constituem 99% do número de empresas formalmente estabelecidas no país, responsável por 60% dos empregos gerados, contribuindo com mais de 50% dos salários, e por 20% de participação no Produto Interno Bruto do país. A questão principal a ser investigada é se estas políticas acontecem de forma eficiente e quais as ações tomadas por estas empresas para se manterem no mercado. Para identificar a percepção dos micro e pequenos empresários sobre a contribuição das políticas de apoio e de fomento do SEBRAE/MS, assim como, suas ações tomadas diante das dificuldades enfrentadas, foram realizadas entrevistas e questionários dirigidos a várias empresas. Foi detectado que apenas uma das 24 empresas que aceitaram em participar da pesquisa, demonstrou estar satisfeita com os serviços prestados pelo SEBRAE/MS. Das 24 empresas analisadas, 14 utilizam ou já utilizaram os serviços do SEBRAE/MS e outras 10, não utilizaram. A metodologia utilizada foi de caráter exploratório, com abordagem qualitativa, utilizando a técnica de análise de discurso. Com base nas teorias utilizadas e nas informações obtidas das entrevistas e questionários, a pesquisa evidenciou que esta insatisfação não é proveniente da existência de alguma ineficiência do SEBRAE/MS, relacionado à falta de conhecimento técnico, e sim, da dificuldade do SEBRAE/MS em atender a ansiedade dos empresários pesquisados em obter respostas prontas e imediatas diante das dificuldades que enfrentam. Isto acontece devido à variedade e o volume de atividades existentes dentro destas empresas, mesmo de micro e pequeno porte, que induzem o micro e pequeno empresário ter uma organização e controle não muito eficiente de sua empresa. Quanto mais organizada e controlada, maior a possibilidade de uma empresa deste porte conseguir definir e melhor aproveitar os serviços de apoio e de fomento do SEBRAE/MS em comparação com aquelas cuja organização e controle são deficientes. / This research aims to analyze the political support and encouragement Micro and Small Enterprises in the state of Mato Grosso do Sul, with reference to the performance of SEBRAE / MS in the period 1990 to 2008, through the perception of entrepreneurs analyzed. The research is part of the important information that the mortality rate of small and micro enterprises is 56% before reaching five years of activities (SEBRAE, 2007). It is a troubling information because, according SEBRAE (2007), the Micro and Small Enterprises constitute 99% of the number of companies formally established in the country, accounting for 60% of jobs, contributing over 50% of salaries , and 20% share of the GDP of the country. The main question to be investigated is whether these policies occur efficiently and that the actions taken by these companies to stay in the market. To identify the perceptions of micro and small entrepreneurs on the contribution of political support and encouragement of SEBRAE / MS, as well as their actions taken in the face of difficulties, we conducted interviews and questionnaires to various companies. It was found that only one of 24 companies that agreed to participate in the study, proved to be satisfied with the services provided by SEBRAE / MS. Of the 24 companies surveyed, 14 use or have used the services of SEBRAE / MS and 10 others, did not. The methodology was exploratory in nature, with a qualitative approach, using the technique of discourse analysis. Based on the theories used and the information obtained from interviews and questionnaires, the survey showed that this dissatisfaction is not from the existence of some inefficiency SEBRAE / MS, related to lack of technical knowledge, but rather the difficulty of SEBRAE / MS address the anxiety of businessmen surveyed in getting immediate answers and the difficulties you face. This is due to the variety and volume of existing activities within these businesses, even micro and small, which leads to micro and small business to have an organization and not very efficient control of your company. The more organized and controlled, the greater the possibility of a company this size get set and enjoy the best support services and promotion of SEBRAE / MS compared with those whose organization and control are disabled.

The mechanical properties of crystalline metals are strongly affected when the sample size is limited to the micron or sub-micron scale. At these scales, the mechanical properties are enhanced far beyond classical predictions. Besides, the surface to volume ratio significantly increases. Therefore surfaces and interfaces play a big role in the mechanical properties of these micro-samples. The effect of different interfaces on the mechanical properties of micro-samples is not yet well understood. The aim of this project is to characterize, understand, and predict the effect of confinement on deformation mechanisms at micro-scale. In this study, micro-pillars were fabricated by Focused Ion Beam (FIB). Micro-pillars were homogeneously coated with thin films by magnetron sputtering and cathodic arc deposition. The mechanical properties of carbon-coated-, chromium coated-, naked-, annealed- and non-annealed micro-pillars were measured. Afterwards, the results of micro-compression tests and Automated Crystal Orientation Mapping on Transmission electron microscopy (ACOM TEM) were compared and led to some surprising new findings.Dislocations are blocked by amorphous- and even crystalline coating in the deformed samples. Parallel slip systems were detected in the chromium layer and the copper micro-pillar. Even though the chromium layer has parallel slip systems, dislocation pile-up at the interface was found after deformation. The most significant finding in this study concerns the back stress of the dislocation pile-up, which affects the dislocation sources and causes an increase of the flow stress to generate new dislocations from these sources. Thermal annealing increases the strength and flow stress of FIB fabricated micro samples. The annealing treatment restores the lattice that was damaged by the FIB fabrication process. A higher stress is required to initiate the dislocation nucleation in a pristine lattice. Techniques of fabrication and investigation were developed to study the role of confinement and interfaces on the mechanical properties of materials at micro scale. Mechanisms of deformation were unraveled and a better understanding of the key parameters was reached. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

L’écotoxicité de nanoparticules de dioxyde de cérium (CeO2 NP) en milieu dulçaquicole a été évaluée à l’aide (i) d’essais monospécifiques standardisés et (ii) de chaînes trophiques expérimentales exposées en microcosme. Aucune toxicité n’a été observée chez Nitzschia palea et Chironomus riparius en conditions monopsécifiques. Une inhibition de croissance a été observée chez les amphibiens Xenopus laevis et Pleurodeles waltl., ainsi qu’une toxicité aiguë chez le xénope et une génotoxicité dose-dépendante chez le pleurodèle. Les expositions en microcosme ont mis en évidence une toxicité aiguë chez le pleurodèle, des modifications des communautés bactériennes, une diminution de la décomposition de la litière, ainsi que des effets tératogènes chez le chironome. Les effets observés varient suivant la nature des CeO2 NP étudiées. L’utilisation d’un système biologique complexe permet l’étude des mécanismes de toxicité dans des conditions plus représentatives des conditions environnementales. / The ecotoxicity of cerium dioxide nanoparticles (CeO2 NPs) was studied on freshwater organisms (i) in standardized monospecific conditions and (ii) on experimental trophic chains exposed in microcosms. No toxicity was observed on Nitzschia palea and Chironomus riparius in monospecific conditions. Growth inhibition was observed on the amphibian species Xenopus laevis and Pleurodeles waltl., as well as acute toxicity and dose-dependent genotoxicity observed on Xenopus and Pleurodeles, respectively. Microcosm experiments revealed acute effects on Pleurodeles, changes in bacterial communities, a decrease in leaf litter decomposition and teratogenicity on chironomids. The observed effects vary depending on the type of CeO2 NPs. The use of complex biological system enables the study of toxicity mechanisms in environmentally relevant conditions.

Micro Frontends är en ny mjukvarusystemarkitektur som påstås lösa många av problemen som drabbar monolitiska frontends med stora kodbaser. Den begränsade andelen forskning som undersökt konceptet har nått motsägelsefulla slutsatser kring arkitekturens effekt i praktiken. Detta är problematiskt då många företag överväger att migrera till arkitekturen men är tveksamma, vilket motiveras av den bristande kunskapen om konceptet. Denna kvantitativa studie ämnar undersöka om utvecklare som jobbar med Micro Frontends upplever dess fördelar och nackdelar genom att jämföra deras upplevelse med utvecklare som jobbar med en monolitisk frontend. Datan samlades in genom en surveyundersökning och analyserades med statistiska metoder. Resultaten av den kvantitativa analysen visade att kodduplicering samt att hålla ett UX konsekvent är problematiska aspekter vid användandet av Micro Frontends. Studiens låga svarsfrekvens gör att dessa resultat inte anses som generaliserbara. / Micro Frontends is a new software system architecture that is said to solve many of the problems that exist in monolithic frontends with large codebases. The limited amount of research that has examined the concept have reached contradictory conclusions about the effect of the architecture in practice. This is problematic as many companies are considering migrating to the Micro Frontend architecture but are hesitant, which is motivated by the lack of knowledge about the concept. This quantitative study aims to investigate whether developers working with Micro Frontends experience its theorized advantages and disadvantages by comparing their experience with developers working with a monolithic frontend. The data were collected through a survey and analyzed using statistical methods. The results of the quantitative analysis showed that code duplication and keeping a consistent UX is problematic when using Micro Frontends. The study's low response rate however means that these results are not considered generalizable.