Crop yields are expected to face more threatening circumstances due to ongoing climatic and environmental change. The continued sustainability of crop production will depend on genetic capacity of crops to adapt to increased biotic and abiotic barriers induced by climate change. Historically, shoot-based traits were breeding targets for overcoming yield gaps between developed and undeveloped nations. However, the rate of genetic gain has stabilized with conventional breeding targets for indirect yield improvement. As the availability of mineral fertilizers is steadily declining and the occurrence of low-fertility soils has increased, reoccurring yield disparities worldwide are propelling us to evaluate new breeding targets. There is potential for plant breeders to shift their focus to the root system architecture (RSA) as a new target for indirect selection, enabled by the phenotypic plasticity of winter wheat (Triticum sp.), one of the main staple agronomic crops. Our current limited understanding of the dynamic nature of the root system architecture is due to the difficulties associated with in situ phenotyping and characterization of anatomical traits. The objectives of this thesis were to 1) review advancements in root phenotyping methodologies and past, present, and future predictions; 2) evaluate differences in root biomass accumulation and remobilization among 22 Virginia Tech-developed elite germplasm; 3) evaluate potential genetic variability for root biomass accumulation across breeding lines. Minimal genetic variation was observed for root biomass accumulation through time. Soil coring proved not to be a very effective method for capturing genetic variability of root biomass accumulation from a soil depth of 10 cm. However, a low genetic signal was also observed for shoot biomass, even though the entire field plot for each genotype was sampled. Yet, a considerably higher genetic signal was observed for plant height. These results suggest that both root and shoot biomass are complex, polygenic traits that require significantly more attention to evaluate genetic differences. / Master of Science / Climate change induces numerous abiotic and biotic barriers to our global cropping systems. Mineral fertilizer reserves are expected to deplete within the next 80 years while our agricultural lands continue losing fertility. This translates into increased yield discrepancies among the most prominent staple agronomic crops. Historically, crop improvement has been performed through indirect selection upon shoot-based traits for yield improvement. However, the capacity of genetic gain from these conventional selection criteria is projected to stabilize. Therefore, it would be beneficial for future global crop production if the initiative was taken to identify a new breeding target that can ensure climate resiliency in staple crops, such as winter wheat (Triticum). Root system architecture (RSA) is defined as the spatial distribution of embryonic and post-embryonic roots throughout a growth medium. This has the potential to become a new breeding target. However, there are numerous difficulties to overcome when evaluating roots in situ. In addition, there is no standardized root phenotyping method that can be implemented nationwide due to the variability in phenotypic response in various growing environments. The objectives of this thesis are to 1) reveal the advancements in root phenotyping and its legitimacy for standardization, 2) explore the genetic architecture of root system architecture, and 3) evaluate the genetic variability of root biomass accumulation for climate resiliency. Minimal genetic variation was observed for root biomass accumulation through time. Soil coring proved not to be a very effective method for capturing genetic variability of root biomass accumulation from a soil depth of 10 cm. However, a low genetic signal was also observed for shoot biomass, even though the entire field plot for each genotype was sampled. Yet, a considerably higher genetic signal was observed for plant height. These results suggest that both root and shoot biomass are complex, polygenic traits that require significantly more attention to evaluate genetic differences.

This thesis presents the results of testing and modeling conducted to characterize the performance of 3M™ VHB™ structural glazing tape in both shear and tension. Creep rupture testing results provided the failure time at a given static load and temperature, and ramp-to-fail testing results provided the ultimate load resistance at a given rate of strain and temperature. Parallel testing was conducted on three structural silicone sealants to compare performance. Using the time temperature superposition principle, master curves of VHB tape storage and loss moduli in shear and tension were developed with data from a dynamic mechanical analyzer (DMA). The thermal shift factors obtained from these constitutive tests were successfully applied to the creep rupture and ramp-to-fail data collected at 23°C, 40°C, and 60°C (73°F, 104°F, and 140°F), resulting in master curves of ramp-to-fail strength and creep rupture durability in shear and tension. A simple linear damage accumulation model was then proposed to examine the accumulation of wind damage if VHB tape is used to attach curtain wall glazing panels to building facades. The purpose of the model was to investigate the magnitude of damage resulting from the accumulation of sustained wind speeds that are less than the peak design wind speed. The model used the equation derived from tensile creep rupture testing, extrapolated into the range of stresses that would typically be generated by wind loading. This equation was applied to each individual entry in the data files of several real wind speed histories, and the fractions of life used at each entry were combined into a total percentage of life used. Although the model did not provide evidence that the established design procedure is unsafe, it suggested that the accumulation of damage from wind speeds below the peak wind speed could cause a VHB tape mode of failure that merits examination along with the more traditional peak wind speed design procedure currently recommended by the vendor. / Master of Science

Model checking is a well-established method for automatic system verification. Besides the extensively studied qualitative case, there is also an increasing interest in the quantitative analysis of system properties. Many important quantities can be formalised as the accumulated values of weight functions. These measures include resource usage such as energy consumption, or performance metrics such as the cost-utility ratio or reliability guarantees. Different kinds of accumulation like summation, averaging and ratios are necessary to cover the diverse spectrum of quantities. This work provides a general framework for the formalisation and verification of system models and property specifications with accumulative values. On the modelling side, we rely on weighted extensions of well-known modelling formalisms. Besides weighted transition systems, we investigate weighted probabilistic models such as Markov chains and Markov decision processes (MDPs). The weights in this sense are functions, mapping each state or transition in the model to a value, e.g., a rational vector. For the specification side, we provide a language in the form of an extension of temporal logic with new modalities that impose restrictions on the accumulated weight along path fragments. These fragments are regular and can be characterised by finite automata, so called monitors. Specifically, we extend linear temporal logic (LTL) and (probabilistic) computation tree logic (CTL) with such constraints. The framework allows variation to weaker formalisms, like non-negative or integral weight functions and bounded accumulation. We study the border of decidability of the model-checking problem for different combinations of these restrictions and give complexity results and algorithms for the decidable fragment. An implementation of the model-checking algorithms on top of the popular probabilistic model checker PRISM is provided. We also investigate several optimization techniques that can be applied to a broad range of formula patterns. The practical behaviour of the implementation and its optimization methods is put to the test by a set of scaling experiments for each model type.:1. Introduction 1.1. Goal of the Thesis 1.2. Main Contributions 1.3. Related Work 1.4. Outline 1.5. Resources 2. Preliminaries 2.1. Modeling Formalisms 2.2. Finite Automata 2.3. Propositional Logic 2.4. Temporal Logics 2.4.1. Linear Temporal Logic 2.4.2. Computation Tree Logic 2.5. Model-Checking Problems 2.5.1. Markov Decision Processes 2.5.2. Markov Chains 2.5.3. Transition Systems 2.5.4. Calculate Probabilities 3. Specifications with Weight Accumulation 3.1. Weight Constraints 3.1.1. Syntax of Weight Constraints 3.1.2. Weighted Models 3.1.3. Interpretation of Weight Constraints 3.1.4. Properties of Weight Constraints 3.2. Monitor Automata 3.2.1. Automata Classes 3.2.2. Observing WMDP Paths 3.3. Variants 3.3.1. Weight Ratios 3.3.2. Other Linear Accumulation Operators 3.3.3. Other Weight Combinations 3.3.4. Filtered Semantics 4. Linear Temporal Logic with Accumulation 4.1. Syntax and Semantics of AccLTL 4.1.1. Syntax of AccLTL 4.1.2. Semantics of AccLTL 4.1.3. Past Variant 4.1.4. Transformation of Weight Functions 4.1.5. Examples for AccLTL Formulae 4.2. Decidability Results for Accumulation LTL 4.2.1. Encoding the Post Correspondence Problem 4.2.2. Reduction of the AccLTL Model-Checking Problem 4.3. Complexity Results for Bounded Accumulation LTL 4.3.1. Transformation to Unweighted MDP and LTL 4.3.2. Reduction to LTL Model-Checking Problems 4.3.3. Algorithm 4.4. Decidability Results for Conic Accumulation LTL and RMDPs 4.4.1. Transformation to Unweighted MDP and LTL 4.4.2. Simple Weight Constraints 4.4.3. 1-dimensional Weight Constraints 4.5. NP-hard and coNP-hard Formulae for WTS and WMCs 4.5.1. Formulae for WTS 4.5.2. Formulae for WMC 4.6. Efficiently Decidable Patterns 4.7. Summary 5. Computation Tree Logic with Accumulation 5.1. Syntax and Semantics 5.1.1. Syntax and Semantics of AccCTL 5.1.2. Syntax and Semantics of AccPCTL 5.2. Decidability Results for Accumulation (P)CTL 5.3. Complexity Results for Bounded Accumulation (P)CTL 5.3.1. Weighted Markov Decision Processes 5.3.2. Weighted Markov Chains 5.3.3. Weighted Transition Systems 5.4. Decidability Results for Conic Accumulation (P)CTL and RMDPs 5.5. Summary 6. Implementation and Experiments 6.1. Implementation Details 6.1.1. Formula Expression 6.1.2. Model Construction 6.2. Optimizations 6.2.1. Single Track Method 6.2.2. Rewriting Without Until 6.2.3. Monitor Filtering 6.2.4. Detection of Optimization Methods 6.3. Scaling Experiments 6.3.1. Scaling Dimensions 6.3.2. Setting 6.3.3. Model Description 6.3.4. Input Size 6.3.5. Optimization Effects 6.3.6. Filtering 7. Conclusions 7.1. Summary 7.2. Outlook and Future Work A. Bibliography B. Material for the experiments B.1. Environment for the Experiments B.1.1. Container Image B.1.2. Model Definitions

My research examines the three interrelated concepts of crisis; new imperialisms, spatial-temporal fix and accumulation by dispossession (ABD) stemming from the work of David Harvey as a way to understand the contested history of the Pakistan Railways. For the first thirty odd years after Pakistan's inception in 1947, the railways, a state-owned institution, was the primary mode of transport for the public, cargo, and workers. Alongside basic infrastructure, the railways had a vast network of hospitals, schools, workers' colonies and an array of physical infrastructure connected to production, operations and other aspects of the economy. The systematic ransack and decline of the Pakistan Railways reached its peak in 2010. Despite several attempts throughout the 1990s by successive democratic and military-led governments backed by the IMF/World Bank in 2015, it was announced that Pakistan railways would be revived under the banner of the 46 billion dollar China Pakistan Economic Corridor (CPEC) as part of the changing geopolitical context of growing regional connectivity and new Chinese imperialism. By examining the processes that underlie ABD, such as spatial-temporal fix, the following research shows that these processes not only reflect a shift of resources away from the public domain, but in Pakistan also entailed the transformation of the railways from a utilitarian welfare organization to an entity that facilitates looting, unbundling, and dispossession of shared resources and infrastructure.

The research explored strategies to improve cover crop (CC) establishment and nitrogen (N) uptake in response to the time constraints commonly faced by Mid-Atlantic farmers. The first study examined whether broadcasting CCs at corn harvest—using various incorporation techniques—can reduce nitrate leaching and enhance biomass production, compared to broadcasting or drilling CCs 4-weeks post-harvest. Four seeding methods were tested across a range of CC species, including cereal rye (Secale cereale L.), hairy vetch (Vicia villosa Roth), rapeseed (Brassica napus L.), and their mixture. Over two years, data revealed that CCs planted at corn harvest achieved significantly higher fall biomass (721 to 846 kg ha-1) than those seeded four weeks later (134 to 200 kg ha-1). Year 2 data showed a reduction in fall soil nitrate levels with at-harvest planting (5.2 mg kg-1), compared to post-harvest CC planting (11.4 to 11.8 mg kg-1). Additionally, certain at-harvest treatments, particularly those with hairy vetch and the mix, increased aboveground N accumulation (181 to 208 kg ha-1) and, in Year 1, improved corn yield (10,113 to 11,586 kg ha-1). The second study focused on a combine-mounted seeder's capacity to address similar N management goals in corn-soybean systems, allowing for seeding CCs directly at harvest and bypassing the need for additional field passes. Results from one year demonstrated that the combine-mounted seeder produced equal or greater biomass and N accumulation compared to delayed drilling. Following corn, the combine seeded treatments increased fall biomass tenfold (205 kg ha-1 vs. 1116 to 1314 kg ha-1) and nearly doubled spring biomass (2345 kg ha-1 vs. 5867 to 6323 kg ha-1). The effectiveness of at-harvest broadcasting was also evident even in late-season drought conditions following soybean, showing comparable results to drilling two weeks post-harvest (4528 kg ha-1 vs. 4434 kg ha-1). Both studies highlight that earlier CC establishment, whether by broadcast seeding with or without incorporation or utilizing combine-mounted seeders, offers a promising approach for enhancing biomass production and reducing fall nitrate leaching in Mid-Atlantic farming systems. / Master of Science / This research examined ways to aid Mid-Atlantic farmers in establishing earlier cover crops (CCs) and improving CC nitrogen (N) uptake. The first part of the study compared broadcasting CCs at corn harvest with waiting four weeks to either broadcast or drill them after harvest. Four species of CCs were tested, including cereal rye, hairy vetch, rapeseed, and a mixture of these. Results over two years showed that broadcasting CCs at corn harvest resulted in significantly more biomass growth in the fall, with levels ranging from 721 to 846 kg per hectare (643 to 755 lb per acre), compared to just 134 to 200 kg per hectare (120 to 178 lb per acre) with later planting. Additionally, soil nitrate levels were lower when CCs were planted at harvest—5.2 mg/kg, compared to 11.4 to 11.8 mg/kg when planted later. Certain combinations, especially those including hairy vetch, led to higher N accumulation and improved corn yields. The second part of the study evaluated a new combine-mounted seeder that allows farmers to plant CCs during cash crop harvest, reducing the number of times they need to work the fields. Results after one year showed that the combine-seeded method produced similar or greater biomass and N accumulation than conventional post-harvest drilling. Following corn, fall biomass increased tenfold and spring biomass nearly doubled compared to delayed drilling. Even with drought conditions in soybeans, the combine-seeded method yielded results comparable to drilling CCs two weeks later. The second year of the study is still in progress. Overall, both studies suggest that starting cover crops earlier, whether by broadcasting or using the combine seeder, can significantly boost biomass growth while reducing nitrate leaching in farming systems throughout the Mid-Atlantic region. Future research is needed to test the effectiveness of the combine-mounted cover crop seeder in different soil types and climates.

CGI-58 is the defective gene in the human neutral lipid storage disease called Chanarin-Dorfman syndrome. This disorder causes intracellular lipid droplets to accumulate in nonadipose tissues, such as skin and blood cells. Here, disruption of the homologous CGI-58 gene in Arabidopsis thaliana resulted in the accumulation of neutral lipid droplets in mature leaves. Mass spectroscopy of isolated lipid droplets from cgi-58 loss-of-function mutants showed they contain triacylglycerols with common leaf specific fatty acids. Leaves of mature cgi-58 plants exhibited a marked increase in absolute triacylglycerol levels, more than 10-fold higher than in wild-type plants. Lipid levels in the oil-storing seeds of cgi-58 loss-of-function plants were unchanged, and unlike mutations in beta-oxidation, the cgi-58 seeds germinated and grew normally, requiring no rescue with sucrose. We conclude that the participation of CGI-58 in neutral lipid homeostasis of nonfat-storing tissues is similar, although not identical, between plant and animal species. This unique insight may have implications for designing a new generation of technologies that enhance the neutral lipid content and composition of corp plants.

Dans l’éventualité où l’important réservoir de carbone que représentent les tourbières venait à être déstabilisé, les impacts sur le climat planétaire pourraient être majeurs. Pourtant, les facteurs influençant les taux d’accumulation de carbone à l’échelle décennale et centennale dans les tourbières n’ont pas clairement été déterminés et les dynamiques passées et contemporaines en matière d’accumulation de carbone ont rarement été comparées pour le même site d’étude. Ce projet visait à (1) reconstruire à l’échelle fine (cm) les taux d’accumulation de carbone pour la tourbière Degerö Stormyr (Suède), (2) identifier les principaux facteurs influençant ces taux d’accumulation et (3) comparer les taux reconstruits aux flux de carbone contemporains mesurés sur le site. Deux approches méthodologiques complémentaires ont été employées : les reconstructions paléoécologiques et la modélisation. Les principales conclusions de ce mémoire sont les suivantes : (1) les taux apparents d’accumulation de carbone sont principalement liés aux conditions hydroclimatiques dans l’acrotelme, mais sont influencés par la composition végétale de la tourbe dans le catotelme. (2) Les taux réels d’accumulation de carbone pour la période récente (≈ 130 dernières années) sont semblables au bilan écosystémique net de carbone mesuré sur le site. (3) La comparaison entre les dynamiques récentes et à plus long terme suggère que Degerö Stormyr a séquestré davantage de carbone au cours des dernières décennies. Les résultats de ce mémoire soulignent l’importance d’étudier les facteurs influençant les taux d’accumulation de carbone pour différentes échelles temporelles et suggèrent que l’accent doit être mis sur l’accumulation de carbone à l’échelle décennale et centennale. / In the event that the important carbon reservoir sequestered in peatlands were to be destabilized, the impacts on global climate could be major. However, the factors influencing carbon accumulation rates at decadal and centennial scale in peatlands have not yet been clearly identified and past and contemporary carbon accumulation dynamics of the same study site have rarely been compared. This project aimed to (1) reconstruct fine scale (cm) carbon accumulation rates for the Degerö Stormyr peatland (Sweden), (2) identify the key factors influencing accumulation rates and (3) compare the reconstructed rates to modern carbon fluxes measured at the site. Two complementary methodological approaches were used: paleoecological reconstructions and modelling. The main conclusions of this thesis are that: (1) Apparent rates of carbon accumulation are mainly related to hydroclimatic conditions in the acrotelm, but are influenced by the vegetation composition of the peat in the catotelm. (2) True rates of carbon accumulation for the recent period (≈ last 130 years) are similar to the net ecosystem carbon balance measured on site. (3) The comparison between recent and long-term carbon accumulation dynamics suggests that Degerö Stormyr has sequestered more carbon over the past decades. The results of this thesis highlight the importance of studying factors influencing carbon accumulation rates at different time scales and suggest that emphasis should be placed on decadal and centennial scales.

Thèse réalisée en cotutelle avec l'Université Européenne de Bretagne - Rennes 2 / Alors que plusieurs auteurs ont souligné l’existence d’un contexte social relativement permissif pour expliquer l’ampleur de la coercition sexuelle dont sont victimes les femmes, cette thèse a privilégié un niveau d’analyse individuel. De concert avec une perspective interactionniste somme toute classique, il a alors été proposé que des facteurs situationnels puissent contribuer à actualiser des facteurs de risque individuels et, par ce biais, précipiter le passage à l’acte. L'objectif général de cette thèse était ainsi d'étudier expérimentalement les effets de l'alcool et de l'excitation sexuelle sur la perception du consentement et les intentions comportementales d'utiliser des stratégies coercitives pour avoir une relation sexuelle. Plus exactement, et afin d’étudier les effets de l’alcool sur la perception des intentions comportementales exprimées par une femme, un plan expérimental inter-participants a permis de répartir aléatoirement 150 participants, issus de la population générale, dans une condition Avec alcool ou dans une condition Sans alcool. La concentration d’alcool dans le sang visée était de 0,8 g/L (2,22 ml de vodka à 40 % par kg). Par la suite, les participants étaient à nouveau répartis aléatoirement dans l'une des deux modalités du facteur Excitation sexuelle, soit Avec excitation sexuelle et Sans excitation sexuelle. Un plan factoriel inter-participants 2x2 a alors permis d'étudier les effets de l'alcool et de l'excitation sexuelle sur le temps de latence pour indiquer qu'une femme n'est plus intéressée par avoir une relation sexuelle, ainsi que sur les intentions comportementales d’utiliser des stratégies coercitives non-violentes et de commettre un viol. Pour ce qui est de la perception des intentions comportementales, les résultats, obtenus à l’aide d’analyses de variance mixte, indiquent qu’il existe une difficulté à percevoir correctement une absence de consentement lorsqu’elle n’est pas exprimée avec suffisamment d’intensité. Toutefois, cette difficulté est indépendante des effets de l’alcool, dans la mesure où elle se manifeste aussi bien chez les hommes qui ont consommé de l’alcool que chez ceux qui n’ont pas consommé d’alcool. Pour ce qui est de l’identification d’une absence de consentement sexuel, les résultats, obtenus à l’aide de modèles de régression linaire multiple et de régression de Cox, indiquent qu’il existe un effet de l’alcool, mais que cet effet est modéré par les distorsions cognitives. Toutefois, si la consommation d’alcool contribue, chez les individus présentant des distorsions cognitives au-delà d’un certain niveau, à différer l’identification d’une absence de consentement sexuel, elle ne l’empêche pas. Enfin, les résultats, issus de modèles de régression linéaire multiple et logistique multiple, indiquent que l’effet de l’alcool sur les intentions comportementales d’utiliser des stratégies coercitives est également modéré (et conditionné) par le niveau de distorsions cognitives. Plus exactement, malgré la perception d’une absence de consentement sexuel, notamment lorsqu’elle est exprimée avec suffisamment d’intensité, les individus qui présentent un niveau particulièrement élevé de distorsions cognitives sont plus à risque d’utiliser des stratégies coercitives non-violentes en l’absence d’alcool, mais sont également plus à risque de commettre un viol lorsqu’ils ont consommé de l’alcool. Par ailleurs, les résultats indiquent que notre manipulation de l’excitation sexuelle pourrait avoir, au moins partiellement, échoué. De nouvelles études apparaissent ainsi nécessaires afin de comprendre le rôle éventuel de l’excitation sexuelle dans la perception du consentement et les intentions comportementales d’utiliser des stratégies coercitives pour avoir une relation sexuelle. Alors que ces résultats ouvrent la voie à de nouvelles recherches afin de mieux comprendre les processus et mécanismes par lesquels l’alcool peut, chez certains individus, contribuer à expliquer la coercition sexuelle, des implications pratiques peuvent également être proposées. Ainsi, si les résultats relatifs à la perception du consentement soutiennent l’importance de programmes de prévention primaire, voire situationnelle, les résultats relatifs aux intentions comportementales d’utiliser des stratégies coercitives soulignent que des programmes de prévention secondaire apparaissent également comme un élément indispensable d’une politique efficace de prévention de la coercition sexuelle. / While a relatively permissive social context has been argued to explain the extent of sexual coercion against women, this dissertation has favored an individual level of analysis. In accordance with a classic interactionist perspective, situational factors have been proposed to contribute to trigger individual risk factors and, therefore, precipitate sexual coercion. The overall objective of this dissertation was to experimentally study the effects of acute alcohol intoxication and sexual arousal on the perception of consent and on behavioral intentions to use coercive strategies to have sex. More precisely, a between-subjects design was used to study the effects of acute alcohol intoxication in men on their perception of a woman’s behavioral intents. The 150 participants, recruited from the general population, were thus randomized either in a condition With alcohol or in a condition Without alcohol. The targeted blood alcohol content was 0,08 % (2,22 ml of 40% alcohol-by-volume Absolut vodka per kg of body weight). Then, participants were once again randomized in one of the two levels of “Sexual arousal” factor: a condition With sexual arousal and a condition Without sexual arousal. A 2x2 between-subjects factorial design was thereby used to study the effects of acute alcohol intoxication and sexual arousal on the latency to indicate that a woman is no longer interested in having sex as well as on the behavioral intentions to use non-violent coercive strategies and to commit rape. First, in regards to the perception of a woman’s behavioral intents, the results of mixed ANOVAs indicate that there exists a difficulty in correctly perceiving an absence of consent if it is not expressed with sufficient intensity. However, this difficulty is independent of the effects of alcohol consumption, as participants in both conditions express this difficulty. Secondly, for the identification of an absence of sexual consent, results of multiple linear regressions and Cox regression indicate that alcohol consumption does have an effect, but this effect is moderated by cognitive distortions. Moreover, if alcohol consumption contributes to postpone the identification of an absence of sexual consent in participants with a higher level of cognitive distortions, it does not ultimately hinder it. Finally, results of multiple linear and multiple logistic regressions indicate that the effect of alcohol consumption on behavioral intentions to use coercive strategies to have sex is also moderated (and conditioned) by the level of cognitive distortions. Despite the fact that participants ultimately correctly perceive an absence of sexual consent, those with a higher level of cognitive distortions are more likely to use non-violent coercive strategies to have sex if no alcohol is consumed and, are also more likely to commit rape when they consume alcohol. Moreover, results indicate that our experimental manipulation of sexual arousal may have partially failed. New studies appear necessary in order to better understand the potential role of sexual arousal on the perception of consent and on behavioral intentions to use coercive strategies. While these results pave the way for new research in order to better understand the processes and mechanisms by which acute alcohol intoxication may help to explain sexual coercion in some individuals, practical implications must also be considered. While results related to the perception of consent support the relevance of primary and situational prevention, results related to behavioral intentions to use coercive strategies to have sex highlight the need for secondary prevention in order to develop an effective policy for sexual coercion prevention.

Ce travail s'inscrit dans le cadre du projet SIMED fédérant les activités de modélisation à l'échelle méditerranéenne, et plus globalement dans le programme MERMEX qui vise à étudier les cycles biogéochimiques en mer Méditerranée et leurs évolutions futures. L'étape préliminaire a été de coupler la plateforme de modélisation hydrodynamique (NEMO) à celle de modélisation biogéochimique mécaniste (Eco3M), afin de réaliser une simulation (2000-2012) utilisant les sorties hydrodynamiques de la configuration NEMO-MED12 pour forcer le modèle biogéochimique Eco3M-MED. Les nombreuses comparaisons menées dans cette thèse (chlorophylle, sels nutritifs, production primaire, etc.) ont aidé à s'assurer de la capacité du modèle à reproduire les principales caractéristiques biogéochimiques de la Méditerranée. Ce travail a permis de généraliser le rôle majeur joué par le carbone organique dissous dans la pompe biologique à l'échelle de la mer Méditerranée. Les résultats montrent que la production de carbone organique particulaire est restreinte aux régions de forte dynamique physique, tandis que l'accumulation de carbone organique dissous dans les eaux de surface est commune à la plupart des régions du bassin. Ce dernier processus s'est avéré dépendant des contenus cellulaires du phytoplancton et des bactéries hétérotrophes. Finalement d'après le modèle, la fraction dissoute du carbone organique contribuerait à hauteur d'environ 64 % à l'exportation dans le bassin Ouest, et de 90 % dans le bassin Est. Le bassin Est -en dépit de sa plus forte oligotrophie- s'avère participer à près de 60 % à l'exportation de carbone organique en mer Méditerranée. / This work is part of the SIMED project which is dedicated to basin-scale modeling of the Mediterranean Sea. It also belongs to the MERMEX program which aims at studying biogeochemical cycles in the Mediterranean Sea and their evolution. The first step of this work was to couple the hydrodynamic modeling platform (NEMO) to the mechanistic biogeochemical modeling platform (Eco3M). We ran a simulation (2000-2012) using the hydrodynamic outputs from NEMO-MED12 configuration to force the biogeochamical model Eco3M-MED. The model evaluation was conducted using numerous field measurements (chlorophyll, nutrients, primary production, etc.). The simulation strengthens and extends to the whole basin the prominent role of dissolved organic carbon in the biological carbon pump in the whole Mediterranean Sea. A comprehensive analysis of organic carbon (particulate and dissolved) production processes production was performed. Results reveal that particulate organic carbon production is restricted to the highly dynamic areas, whereas dissolved organic carbon accumulation in the surface layers is a common process in much areas of the basin. This latter process appeared to dependant on the cellular contents of phytoplancton and heterotrophic bacteria, themselved being controled by low phosphate availability. Finally, the dissolved organic carbon contribution to carbon export is around 64 % in the Western basin, and up to 90 % in the Eastern basin. When taking into account the dissolved fraction, total organic carbon export in the Eastern basin -despite its higher oligotrophy- exceeds the one in the Western basin (60% against 40 %).

Cette thèse a été effectuée dans le cadre d'un projet qui vise à explorer les facteurs limitants des performances d'une horloge à ions dans le domaine des fréquences micro-onde. Ce travail repose sur l'observation et la manipulation d'un grand nuage d'ions dans des potentiels de géométries différentes. Le but est l'analyse et le transport d'un grand nuage pouvant dépasser 10^6 ions dans un piège radio-fréquence linéaire à plusieurs zones. Notre groupe à construit un piège à trois zones destiné au piégeage d'ions calcium: deux parties quadrupolaires et une partie octupolaire montées en ligne. Les ions sont créés dans la première partie quadrupolaire et refroidis par laser le long de l'axe du piège. Nous avons d'abord étudié la création d'un grand nuage. La limite actuelle des paramètres du système permet de confiner et détecter des nuages de taille maximale 1,2.10^5 ions. Ensuite, grâce à un protocole de transport rapide et optimisé, ces ions sont transportés dans le deuxième et troisième piège avec une efficacité pouvant atteindre 100%. Les résultats en fonction de la durée de transport montrent une asymétrie entre les deux sens de transport que nous exploitons pour ajouter des ions dans le deuxième piège sans perte du nuage initialement présent. Cette technique d'accumulation a permis de piégér 2,5.10^5 ions dans le deuxième et troisième piège. Ce nombre semble limité par les refroidissement. Enfin, dans l'octupole, les observations montrent que, contrairement aux structures creuses attendues par les modèles, les ions froids s'organisent dans trois minima locaux de potentiels. La cause de cette différence est un petit défaut dans la symétrie octupolaire des barreaux. / This thesis is part of a project aiming to explore the performance limiting factors of a microwave ion clock. This work is based on the observation and manipulation of a large ion cloud in potentials with different geometries. The purpose is to analyze and transport a large cloud of more than 10^6 ions in a linear radio-frequency trap with several zones. Our group has build a three-zone trap for calcium ion trapping: two quadrupole parts and an octupole part mounted inline. Ions are created in the first quadrupole part and cooled by lasers along the trap symmetry axis. We study the creation of a large ion cloud. The current trapping and cooling parameters limit the maximum size of the cloud to 1,2.10^5 ions. with a rapid and optimized transport protocol, these ions are transfered in the second part of the trap and then in the octupole trap with an efficiency of up to 100%. The result as function of the transport duration shows an asymmetry between the two transport directions. We exploit this feature to add ions in the second or third trap without loss of the already trapped ions. This accumulation technique has allowed to trap 2,5.10^5 ions in the second and third trap. The cooling laser power seems to be the major limiting factor of this number. Finally the observation of the ions in the octupole shows that the cold ions are localised in three different potential wells. This is in contradiction with the hollow structure predicted by the analytical fluid model and molecular dynamics simulations. The cause of this difference is a tiny defect in the octupole symmetry of the RF-electrodes which leads to local minima in the multipole potential.