L'étude des différentes populations d'étoiles de la Voie Lactée permet de décrire l'histoire de sa formation et de son évolution. Ainsi, le présent travail de thèse constitue une étape supplémentaire dans notre volonté de mieux comprendre l'origine du disque galactique. La compilation de données chimiques et cinématiques et l'identification des groupes cinématiques nous a permis d'établir un état des lieux de nos connaissances sur les relations entre les abondances chimiques et la cinématique du disque mince et du disque épais. A partir d'échantillons significatifs, nous avons pu confirmer certaines de leurs propriétés déjà observées, de mieux contraindre des points plus controversés et enfin de rapporter de nouveaux faits observationnels. Cependant notre étude n'est basée que sur plusieurs centaines d'étoiles situées dans notre voisinage solaire. C'est pourquoi il a été mis au point TGMETalpha, une méthode automatique, dite de ''distance minimum'', basée sur la comparaison de spectres observés avec une grille de spectres synthétiques, permettant de déterminer les paramètres atmosphériques tels que Teff, logg, [Fe/H] et surtout [alpha/Fe] pour de grands volumes de données spectroscopiques à basse et haute résolutions. TGMETalpha offre ainsi la possibilité de sonder beaucoup plus loin de part et d'autre du plan galactique. Cela a été en partie réalisé grâce au catalogue d'étoiles du SDSS, DR3, qui contient plusieurs milliers d'objets situés loin du plan galactique. Notamment entre 1 et 3 kpc, là où le disque épais est la population dominante. Cela a permis d'étudier les propriétés du disque épais en relation avec une population représentative du halo. Certaines propriétés du disque épais et du halo ont pu être vérifiées et de nouveaux faits observationnels ont été mis en évidence, notamment, l'existence d'un gradient radial négatif, significatif, dans le disque épais, ce qui n'avait jamais été montré auparavant. Cette nouvelle contrainte forte indique que la production des éléments alpha par rapport au fer a été plus efficace dans les régions centrales de la galaxie que dans les régions externes. Ce nouveau fait doit être absolument pris en compte dans les prochains scénarios de formation du disque. De plus la présence de débris de galaxies satellites semble être mise en évidence, à partir de leur vitesse de rotation, de leur métallicité [Fe/H] et de leur rapport [alpha/Fe], dans la population du halo, à |z|> 8 kpc. Pour aller plus loin, TGMETalpha pourrait être utilisé pour analyser un plus grand nombre d'étoiles (par exemple à partir du DR5 mais aussi du survey SEGUE qui est l'extension du SDSS, ou encore du survey RAVE ou Gaia) et ainsi analyser les propriétés du disque épais, du halo mais aussi de nombreux ''moving groups'' comme des reliquats de galaxies satellites.

La réponse des traits à l'environnement a été étudiée essentiellement à travers la moyenne des attributs de trait des espèces et des lignées et a récemment été étendue à la variabilité intraspécifique. Cependant, les traits peuvent également répondre aux contraintes de l‟environnement par (i) une forte détermination mutuelle des traits au sein des individus ou des populations, i.e. une forte intégration phénotypique, et (ii) une faible variation des traits au sein de lignées phylogénétiques entières. Nous avons testé : (i) les effets de l'environnement abiotique et biotique sur l'intégration phénotypique chez des espèces végétales subantarctiques et les conséquences écologiques et biogéographiques d'une forte intégration phénotypique, et (ii) les effets de l‟environnement abiotique et biotique sur la variabilité phénotypique réalisée au sein des genres d'Angiospermes de l'Europe Centrale. Pour le premier aspect, nous avons constaté que l'intégration phénotypique est plus forte en conditions abiotiques stressantes. Le renforcement de l'intégration phénotypique se produit sur de petites échelles spatiales et peut limiter la flexibilité à grande échelle des stratégies de croissance et de reproduction. Nous avons également montré que la forte intégration phénotypique et environnementale peut contribuer à l'endémisme de certaines espèces subantarctiques, probablement par une spécialisation sur le long terme de ces espèces à leur habitat. Pour le second aspect, nous avons observé que la variabilité phénotypique réalisée au sein des genres de l'Europe Centrale est plus élevée dans des conditions abiotiques intermédiaires, ce qui reflète une plus grande indépendance des traits vis-à-vis de l'environnement abiotique. Nous avons également montré que le nombre d'espèces en coexistence est très conservé au sein des genres. Un niveau intermédiaire de coexistence semble coïncider avec à la fois une position intermédiaire des genres le long de gradients abiotiques et une plus grande variabilité de certains traits. Ceci suggère un rôle des interactions biotiques nombreuses, mais toujours prévisibles, pour le maintien (ou l'évolution) de niveaux élevés de variabilité des traits au sein des clades. Finalement, l'ensemble de nos résultats suggèrent que la capacité des espèces à répondre aux variations de l'environnement pourrait être fortement limitée aussi bien au niveau des phénotypes individuels qu'à l'échelle des clades entiers, notamment dans des environnements abiotiques et biotiques extrêmes.

<p>In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits, and population differentiation in the insect-pollinated, outcrossing, perennial herb <i>Arabidopsis lyrata</i>. More specifically, I (1) determined whether selection on flowering phenology and floral display can be attributed to interactions with pollinators and herbivores, (2) examined whether population differentiation in flowering phenology and floral display is correlated with current selection on these traits, and (3) tested for local adaptation from contrasting environments in Europe.</p><p>A field experiment conducted in a Swedish population demonstrated, that interactions with pollinators may markedly affect selection on both floral display and phenology of flowering. In an alpine population in Norway, grazing damage to inflorescences strongly influenced selection on floral display. The results suggest that variation in the abundance of pollinators and herbivores should contribute to spatio-temporal variation in selection on flowering phenology and floral display in <i>A. lyrata</i>. </p><p>A common-garden experiment showed that flowering phenology and floral display vary among Scandinavian populations of <i>A. lyrata</i>. For some traits patterns of population differentiation were consistent with differences in the direction and strength of phenotypic selection determined in comparisons (a) between an alpine population in Norway and a coastal population in Sweden, and (b) among coastal populations in Sweden. This suggests that current selection contributes to the maintenance of genetic differentiation in these traits.</p><p>Adaptive differentiation among populations was examined in a reciprocal transplant experiment that included populations from three contrasting environments, alpine Norway, coastal Sweden and lowland, continental Germany. The experiment provided evidence for local adaptation, and indicated that populations have diverged in traits affecting plant establishment and early growth.</p>

In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits, and population differentiation in the insect-pollinated, outcrossing, perennial herb Arabidopsis lyrata. More specifically, I (1) determined whether selection on flowering phenology and floral display can be attributed to interactions with pollinators and herbivores, (2) examined whether population differentiation in flowering phenology and floral display is correlated with current selection on these traits, and (3) tested for local adaptation from contrasting environments in Europe. A field experiment conducted in a Swedish population demonstrated, that interactions with pollinators may markedly affect selection on both floral display and phenology of flowering. In an alpine population in Norway, grazing damage to inflorescences strongly influenced selection on floral display. The results suggest that variation in the abundance of pollinators and herbivores should contribute to spatio-temporal variation in selection on flowering phenology and floral display in A. lyrata. A common-garden experiment showed that flowering phenology and floral display vary among Scandinavian populations of A. lyrata. For some traits patterns of population differentiation were consistent with differences in the direction and strength of phenotypic selection determined in comparisons (a) between an alpine population in Norway and a coastal population in Sweden, and (b) among coastal populations in Sweden. This suggests that current selection contributes to the maintenance of genetic differentiation in these traits. Adaptive differentiation among populations was examined in a reciprocal transplant experiment that included populations from three contrasting environments, alpine Norway, coastal Sweden and lowland, continental Germany. The experiment provided evidence for local adaptation, and indicated that populations have diverged in traits affecting plant establishment and early growth.

About 6% of all angiosperms are dioecious. This separation of sexual function to male and female individuals, and the fundamentally different patterns of reproductive resource allocation that follows that separation, are thought to have important ecological and evolutionary consequences for plant enemy interactions.  I have studied whether intersexual differences in susceptibility to natural enemies can be explained by intersexual differences in resource allocation. In cases when sexual dimorphic traits form the target resource of a particular enemy I expected the enemy to select the best resource. The study system is the perennial dioecious herb, Silene dioica (Caryophyllaceae) and three of its specialist natural enemies, two insect herbivores the fly Delia criniventris (Anthomyiidae) and the twirler moth Caryocolum viscariella (Gelechiidae) and one systemic anther smut fungus Microbotryum violaceum. All three share the same food recourse, the floral stems, of their host plant. I studied the interaction on nine islands in a rising Bothinan archipelago over seven consecutive years. Both herbivores attacked female plants more than male plants (D. criniventris, 32.8% females, 30.7% males; C. viscariella, 4% females, 2% males). This attack pattern was consistent over years and islands and also correlated with a number of sexually dimorphic traits suggesting that females offer the better resource. Herbivore attack had no effect on plant survival but a significant effect on re-flowering the following year. Non-attacked females had an estimated mean re-flowering rate of 30.2%, and non-attacked males of 31%. Herbivore-attacked females had an estimated re-flowering rate of 46% compared with 38.4% for males. Females showed a stronger compensatory response to attack and tended to re-flower more often than males. Attack rates differed markedly in the different stages of primary succession. They were consistently higher in the youngest zone and decreased in parallel to progressing succession. This zonal pattern of decreasing attack rates correlated with several plant attributes, a decrease in plant size and nitrogen content, and an increased content of secondary compounds, but not to host plant density. We failed to come up with a simple explanation for the spatial structure with chronic high attack rates in the younger zones. However, the consistent patterns in attack rate suggest that a suite of abiotic and biotic factors interact and reinforce the strength and direction of selection. In general females were more frequently diseased by the anther smut Microbotryum violaceum than males with two exceptions. Disease frequencies were male biased on islands with low disease levels and in one of the seven study years. The change in disease frequencies from male to female bias confirm earlier studies suggesting that the relative contribution of the two components of infection risk, disease encounter and per contact infection probability can vary with population disease level. The change in the proportions of diseased males and females that was observed in one of the study years, followed a year of extreme weather conditions (prolonged drought). Both sexes showed a similar decline in flowering but diseased females decreased more than diseased males. This difference in response can be explained if considering that disease is more resource demanding in females than in males. Except for resources needed for mycelial growth and spore production, in females resources are also needed to restructure their sex expression and produce anthers. My study shows (i) that in dioecious species traits that are sexually dimorphic are of great importance for understanding the outcome of interactions with natural enemies, (ii) that the strengths and directions of enemy-host plant interactions are strongly shaped by both biotic and abiotic conditions.

Solid oxide fuel cells (SOFCs) are high temperature (600C-1000C) composite metallic/ceramic-cermet electrochemical devices. There is a need to effectively manage the heat transfer through the cell to mitigate material failure induced by thermal stresses while yet preserving performance. The present dissertation offers a novel thermodynamic optimization approach that utilizes dimensionless geometric parameters to design a SOFC. Through entropy generation minimization, the architecture of a planar SOFC has been redesigned to optimally balance thermal gradients and cell performance. Cell performance has been defined using the 2nd law metric of exergetic efficiency. One constrained optimization problem was solved. The optimization sought to maximize exergetic efficiency through minimizing total entropy production while constraining thermal gradients. Optimal designs were produced that had exergetic efficiency exceeding 92% while maximum thermal gradients were between 219 C/m and 1249 C/m. As the architecture was modified, the magnitude of sources of entropy generation changed. Ultimately, it was shown that the architecture of a SOFC can be modified through thermodynamic optimization to maximize performance while limiting thermal gradients. The present dissertation highlights a new design methodology and provides insights on the connection between thermal gradients, performance, sources of entropy generation, and cell architecture.

A deeper understanding of Cu(In,Ga)Se2 (CIGS) solar cells is important for the further improvement of these devices. This thesis is focused on the use of electrical modelling as a tool for pursuing this aim. Finished devices and individual layers are characterized and the acquired data are used as input in the simulations. Band gap gradients are accounted for when modelling the devices. The thesis is divided into two main parts. One part that treats the influence of cadmium free buffer layers, mainly atomic layer deposited (Zn,Mg)O, on devices and another part in which the result of CIGS absorber layer modifications is studied. Recombination analysis indicates that interface recombination is limitting the open circuit voltage (Voc) in cells with ZnO buffer layers. This recombination path becomes less important when magnesium is introduced into the ZnO giving a positive conduction band offset (CBO) towards the CIGS absorber layer. Light induced persistent photoconductivity (PPC) is demonstrated in (Zn,Mg)O thin films. Device modelling shows that the measured PPC, coupled with a high density of acceptors in the buffer-absorber interface region, can explain light induced metastable efficiency improvement in CIGS solar cells with (Zn,Mg)O buffer layers. It is shown that a thin indium rich layer closest to the buffer does not give any significant impact on the performance of devices dominated by recombination in the CIGS layer. In our cells with CdS buffer the diffusion length in the CIGS layer is the main limitting factor. A thinner CIGS layer improves Voc by reducing recombination. However, for thin enough absorber layers Voc deteriorates due to recombination at the back contact. Interface recombination is a problem in thin devices with Zn(O,S) buffer layers. This recombination path is overshadowed in cells of standard thickness by recombination in the CIGS bulk. Thin cells with Zn(O,S) buffer layers have a higher efficiency than CdS cells with the same absorber thickness.

La disponibilitat de metalls per part dels organismes no depèn únicament de la concentració total sinó també de l'especiació d'aquestes subtancias. En general, la disponibilitat de les espècies metàl•liques en medis naturals per a organismes està determinada per un conjunt d'esdeveniments encadenats on el equilibri representa només un cas particular de la situació dinàmica general. Espècies poc definides químicament, com ara àcids húmics i fúlvics, actuen com a lligands de metalls i juguen un paper clau en la circulació i la determinació de les propietats ecotoxicològiques de les espècies metàl•liques en medis naturals. La polifuncionalitat dels àcids húmics i fúlvics és descrita en aquest estudi utilitzant mètodes termodinàmics i mecano-estadístics. La tècnica Diffusive Gradients in Thin films (DGT) s'ha utilitzat per mesurar el flux disponible de metall en un sistema sintètic que conté complexos metàl•lics. La principal conclusió d'aquest estudi és que el disc de resina quelant dels sensors juga un paper clau en la determinació del grau de labilitat d'un complex mesurat amb aquesta tècnica. D'altra banda, a un pH baix, o concentració alta de lligand, es pot aconseguir l'equilibri entre la resina del sensor i el metall en el si de la dissolució, pertorbant l'acumulació lineal a temps de contacte relativament curts. Es presenta una anàlisi d'aquests fenòmens, així com la seva justificació mitjançant models teòrics. / La disponibilidad de metales por parte de los organismos no depende únicamente de la concentración total sino también de la especiación de estas subtancias. En general, la disponibilidad de las especies metálicas en medios naturales hacia organismos está determinada por un conjunto de eventos encadenados cuyo equilibrio representa sólo un caso particular de la situación dinámica general. Especies poco definidas químicamente, tales como ácidos húmicos y fúlvicos, actúan como ligandos de metales y juegan un papel clave en la circulación y la determinación de las propiedades ecotoxicológicas de las especies metálicas en los medios naturales. La polifuncionalidad de los ácidos húmicos y fúlvicos es descrita en este estudio usando métodos termodinámicos y mecano-estadísticos. La técnica Diffusive Gradients in Thin films (DGT) se ha utilizado para medir el flujo disponible de metal en un sistema sintético que contiene complejos metálicos. La principal conclusión de este estudio es que el disco de resina quelatante de los sensores juega un papel clave en la determinación del grado de labilidad de un complejo medido esta técnica. Por otra parte, a un pH bajo, o a concentración alta de ligando, puede ser alcanzado el equilibrio entre la resina del sensor y el metal en el seno de la disolución, perturbando la acumulación lineal a tiempos de contacto relativamente cortos. Se presenta un análisis de estos fenómenos, así como su justificación mediante modelos teóricos. / Availability of metals for organisms does not depend only on the total metal concentration but also on speciation of these species. In general, the availability towards organisms is determined by a set of chained events whose equilibrium approach only represents a simplified limiting case of the general dynamic situation. Poorly defined species such as humic and fulvic acids, act as metal ligands and play a key role in the circulation and determination of the ecotoxicological properties of metal species in the natural media. Thermodynamic and statistical mechanics methods are here applied to describe the polyfunctionality of humic and fulvic acids. The Diffusive Gradients in Thin Films (DGT) has been used to measure the available metal flux in a synthetic system that contains metal complexes. A main conclusion of this study is that the chelating resin disc of the sensor plays a key role in determining the lability degree of a complex measured with DGT. Moreover, at relatively low pH, or in presence of high affinity ligands, the equilibrium with the bulk metal concentration can be approached in the sensor, disturbing linear accumulations at relatively short deployment times. Analysis of these phenomena and theoretical explanations are reported.

In this thesis, simple methods to determine sulfide at low levels (µg L-1) in aqueous samples and sediments by water free hydrogen sulfide vapor generation using a commercially available vapor generation accessory have been developed. The hydrogen sulfide is then introduced in the ICP-QMS, equipped with an octopole collision/reaction cell which is vented with hydrogen and helium gases, or in the ICP-AES where the optical path between the plasma and the monochromator is purged with nitrogen. Moreover some studies have been conducted for the determination of arsenic by ICP-MS in natural waters with high sodium and chloride content. Spectral and non spectral interferences on arsenic measurement have been investigated and different experiments have been developed to solve such interferences (optimizations of the cell collision conditions, arithmetic corrections, introduction of small amounts of alcohol). Finally, the use of the DGT technique (diffusive gradients in thin films) has been evaluated in acidic samples and mining wastes for the firs time. / En aquesta tesi, s’han desenvolupat mètodes senzills per a la determinació de sulfur a baixes concentracions (µg L-1) en mostres aquoses i sediments mitjançant la generació de sulfur d’hidrogen, utilitzant un accessori de generació d’hidrurs comercial. Un cop format el sulfur d’hidrogen, aquest es pot introduir a l’ICP-QMS, equipat amb una cel•la de col•lisió/reacció o a l’ICP-AES amb el pas entre el plasma i el monocromador purgat amb nitrogen. També s’han fet alguns estudis per determinar arsènic amb ICP-MS en aigües naturals amb alt contingut de sodi i clor. S’han estudiat les interferències espectrals i no espectrals sobre aquest element i s’han dut a terme diferents experiments per a resoldre-les (optimització de la cel•la de col•lisió, aplicació de correccions matemàtiques, introducció de petites quantitats d’alcohol). Finalment, s’ha avaluat l’ús de la tècnica de DGT (diffusive gradients in thin films) en mostres àcides (pHs de 5 a 10) i residus de mineria per primera vegada.

Clostridium chauvoei is a gram-positive, spore-forming anaerobic bacterium. It is the pathogenic agent of blackleg, a disease causing serious toxemia and high mortality in cattle, sheep and many other domestic and wild animals. It is considered the most important Clostridium producing economic losses in livestock. Typically, animals infected with blackleg die rapidly without any signs of illness. Animals quickly die within 12 to 48 hours after contracting the disease. Therefore, the control of this disease is done by commercial vaccines consisting of whole formolized cultures. Immunity against C. chauvoei is associated with whole cell, including its somatic and flagellar antigens while in other clostridial diseases, protective immunity is obtained by the use of vaccines containing toxoids. Moreover, it is essential to obtain new information about the somatic antigens of C. chauvoei. Proteomics is the study of the proteome, the protein complement of the genome. The proteome has been defined as the entire complement of proteins expressed by a cell, organism, or tissue type, and accordingly, proteomics is the study of this complement expressed at a given time or under certain environmental conditions. 2-DE with Immobilized pH Gradients (IPGs) combined with protein identification by Mass Spectrometry (MS) is currently the workhorse for proteomics. Much of information about immunogenic component can be derived from proteomics coupled to Western blotting, namely immunoproteomics. Our study constitutes the first immunoproteomic analysis of C. chauvoei to identify candidate immunogenic antigens for development of new vaccines. Analyses were performed by Western blot and dot blot techniques against the whole cell extract proteins of C. chauvoei separated by 2-DE. Firstly, the growth conditions of two different strains, C. chauvoei ATCC 11957 and C. chauvoei 20 were optimized. After mice immunization studies with experimental vaccines prepared, sera were obtained for evaluation of the immunoglobulin G antibody level by ELISA. After high level of antibody response determination, 1-DE, 2-DE and immunoblot studies were performed for the characterization of immunogenic proteins. In the study, a total of 460 protein spots could be detected on the 2-DE gels by the help of Delta2D image analysis software and 30 of them were reacted with polyclonal antibodies against inactivated whole cells of C. chauvoei. Among these 30 spots, and 8 of them could be characterized by MALDI-TOF MS analyses. Of these 8 spots revealed four different gene products (distinct ORFs). Ornithine decarboxylase, methionine adenosyltransferase, glucose-6-phosphate isomerase, and flagellin protein FliB (C) are the characterized proteins. Glucose-6-phosphate isomerase has been identified as an immunogenic protein for a pathogenic microbe and in C. chauvoei for the first time. Methionine adenosyltransferase and ornithine decarboxylation were identified as immunogenic for C. chauvoei for the first time. The last defined protein is the flagellin protein FliB(C) which is known to be major immunogenic protein of C. chauvoei.