<p>The objective of the thesis was to explore the potential of diatoms (<i>Bacillariophyceae</i>) as indicators of Holocene climate and environmental change in northern Sweden (Abisko region, 68°21'N, 18°49'E). A modern surface-sediment calibration set including 100 lakes was developed and lake-water pH, sedimentary organic content (assessed by loss-on-ignition) and temperature were identified as most powerful environmental variables explaining the variance within the diatom assemblages. Transfer functions based on unimodal species response models (WA-PLS) were developed for lake-water pH and mean July air temperature (July T), yielding coefficients of determination of 0.77 and 0.70, and prediction errors based on leave-one-out cross-validation of 0.19 pH units and 0.96 °C for lake-water pH and July T, respectively. The transfer functions were validated with monitoring data covering two open-water seasons (lake-water pH) and meteorological records covering the 20th century (July T). The good agreement between diatom-based inferences and measured monitoring data confirmed the prediction ability of the developed transfer functions. </p><p>Analysing a Holocene sediment core from a lake nearby Abisko (Vuoskkujávri), diatoms infer a linearly decreasing July T trend (1.5 °C) since 6,000 cal. BP, which compares well with inferences based on chironomids and pollen from the same sediment core. The lake-water pH inference shows a pattern of moderate natural acidification (c. 0.5 pH units) since the early Holocene, reaching present-day pH values at c. 5,000 cal. BP. By fitting fossil diatom samples to the modern calibration set by means of residual distance assessment within canonical correspondence analysis (CCA), the early Holocene (between 10,600 and 6,000 cal. BP) was identified as a problematic time-period for diatom-based inferences and, consequently, reconstructions during this period are tentative. Pollen-based inferences also show 'poor' fit between 10,600 and 7,500 cal. BP and chironomids probably provide the most reliable July T reconstruction at Vuoskkujávri, with 'poor' fit only during the initial part of the Holocene (between 10,600 and 10,250 cal. BP). </p><p>Possible factors confounding diatom-based July T inferences were investigated. Using detrended CCA (DCCA), Holocene sediment sequences from five lakes indicate that during the early Holocene, mainly physical factors such as high minerogenic erosion rates, high temperature and low light availability may have regulated diatom assemblages, favouring <i>Fragilaria</i> species. In all five lakes, diatom assemblages developed in a directional manner, but timing and scale of development differed substantially between lakes. The differences are attributed primarily to the geological properties of the lake catchments (with strong effects on lake-water pH), but other factors such as climatic change, vegetation, hydrologic setting and in-lake processes appear to regulate diatom communities in each lake differently. The influence of long-term natural acidification on diatom assemblages progressively declined during the Holocene with corresponding increase of the influence of climatic factors.</p>

The objective of the thesis was to explore the potential of diatoms (Bacillariophyceae) as indicators of Holocene climate and environmental change in northern Sweden (Abisko region, 68°21'N, 18°49'E). A modern surface-sediment calibration set including 100 lakes was developed and lake-water pH, sedimentary organic content (assessed by loss-on-ignition) and temperature were identified as most powerful environmental variables explaining the variance within the diatom assemblages. Transfer functions based on unimodal species response models (WA-PLS) were developed for lake-water pH and mean July air temperature (July T), yielding coefficients of determination of 0.77 and 0.70, and prediction errors based on leave-one-out cross-validation of 0.19 pH units and 0.96 °C for lake-water pH and July T, respectively. The transfer functions were validated with monitoring data covering two open-water seasons (lake-water pH) and meteorological records covering the 20th century (July T). The good agreement between diatom-based inferences and measured monitoring data confirmed the prediction ability of the developed transfer functions. Analysing a Holocene sediment core from a lake nearby Abisko (Vuoskkujávri), diatoms infer a linearly decreasing July T trend (1.5 °C) since 6,000 cal. BP, which compares well with inferences based on chironomids and pollen from the same sediment core. The lake-water pH inference shows a pattern of moderate natural acidification (c. 0.5 pH units) since the early Holocene, reaching present-day pH values at c. 5,000 cal. BP. By fitting fossil diatom samples to the modern calibration set by means of residual distance assessment within canonical correspondence analysis (CCA), the early Holocene (between 10,600 and 6,000 cal. BP) was identified as a problematic time-period for diatom-based inferences and, consequently, reconstructions during this period are tentative. Pollen-based inferences also show 'poor' fit between 10,600 and 7,500 cal. BP and chironomids probably provide the most reliable July T reconstruction at Vuoskkujávri, with 'poor' fit only during the initial part of the Holocene (between 10,600 and 10,250 cal. BP). Possible factors confounding diatom-based July T inferences were investigated. Using detrended CCA (DCCA), Holocene sediment sequences from five lakes indicate that during the early Holocene, mainly physical factors such as high minerogenic erosion rates, high temperature and low light availability may have regulated diatom assemblages, favouring Fragilaria species. In all five lakes, diatom assemblages developed in a directional manner, but timing and scale of development differed substantially between lakes. The differences are attributed primarily to the geological properties of the lake catchments (with strong effects on lake-water pH), but other factors such as climatic change, vegetation, hydrologic setting and in-lake processes appear to regulate diatom communities in each lake differently. The influence of long-term natural acidification on diatom assemblages progressively declined during the Holocene with corresponding increase of the influence of climatic factors.

The plant genus Tolpis (Asteraceae) is a predominantly insular plant lineage. It inhabits four of the five archipelagoes that comprise the Atlantic region of Macaronesia and also occurs in Mediterranean Europe and North Africa. Twelve species are currently recognized in Tolpis, of which ten are insular and two continental. The majority of the insular species inhabit the five western Canarian islands, where they constitute endemics to specific ecological habitats. A comprehensive molecular phylogeny of Tolpis is generated via DNA sequences of one nuclear ribosomal and two low-copy nuclear DNA markers. Considerable phylogenetic uncertainty among inferred tree topologies is detected, and incongruence between these topologies is resolved via statistical hypotheses testing. The extant diversity of the genus is identified to be the result of two independent colonization pathways and adaptive radiations on several islands. Moreover, potential hybridization is detected between species that inhabit different islands and archipelagoes, indicating a more widespread historical distribution of the genus. Details of the biogeographic history of Tolpis are inferred via ancestral area reconstructions under parsimony and likelihood optimality criteria. The hypothesis that Tolpis may have undergone a back-dispersal from an island to a continental habitat is also tested. Uncertainty in taxon cladograms owing to the presence of hybrid or allopolyploid taxa is characterized and a potential adjustment strategy evaluated. Averaging reconstruction results over all optimal phylogenetic trees and the manual pruning of cloned DNA sequences are found potential adjustment strategies against the impact of topological uncertainty owning to hybrid or allopolyploid taxa. Adjusted ancestral area reconstructions in Tolpis do not support the scenario that the genus has undergone a reverse colonization of the continent. In addition to the phylogenetic and biogeographic history of the genus, the diversity of symbiotic mycorrhizal fungi associated with Tolpis is characterized. A molecular survey using two nuclear ribosomal DNA markers and 454 pyrosequencing is performed. Particular emphasis is placed on the quality filtering of resulting fungal DNA sequences, the generation of operational taxonomic units, and their taxonomic assignment via similarity searches against DNA sequence databases. Numerous potentially novel fungal genotypes are identified. / text

Computed tomography is one of the most evolving fields of modern radiology. The current CT applications permit among other things angiography, 3D image reconstructions, material decomposition and tissue characterization. CT is an important tool in the assessment of specific patient populations prior to an invasive or surgical procedure. The aim of this dissertation was to demonstrate the decisive role of CT with 3D-image reconstructions in haemodialysis patients scheduled to undergo fistulography, in patients undergoing surgical breast reconstructions with a perforator flap and in patients with complicated renal calculi scheduled to undergo percutaneous nephrolithotomy. CT Angiography with 3D image reconstructions was performed in 31 patients with failing arteriovenous fistulas and grafts, illustrating the vascular anatomy in a comprehensive manner in 93.5% of the evaluated segments and demonstrating a sensitivity of 95% compared to fistulography. In 59 mastectomy patients scheduled to undergo reconstructive breast surgery with a deep inferior epigastric perforator flap, the preoperative planning with CT Angiography with 3D image reconstructions of the anterior abdominal wall providing details of its vascular supply, reduced surgery time significantly (p&lt; 0.001) and resulted in fewer complications. Dual Energy CT Urography with advanced image reconstructions in 31 patients with complicated renal calculi scheduled to undergo PNL, resulted in a new method of material characterisation (depicting renal calculi within excreted contrast) and in the possibility of reducing radiation dose by 28% by omitting the nonenhanced scanning phase. Detailed analysis of the changes renal calculi undergo when virtually reconstructed was performed and a comparison of renal calculi number, volume, height and attenuation between virtual nonenhanced and true nonenhanced images was undertaken. All parameters were significantly underestimated in the virtual nonenhanced images. CT with 3D-reconstructions is more than just “flashy images”. It is crucial in preoperative planning, optimizes various procedures and can reduce radiation dose.

Dans le domaine de la radiobiologie, les dommages causés à l'ADN nucléaire sont largement étudiés puisque l’ADN est considéré la cible la plus sensible dans la cellule. En plus de l’ADN, les mitochondries commencent à attirer l'attention comme des cibles sensibles, car elles contrôlent de nombreuses fonctions importantes pour la survie de la cellule. Ce sont des organites à double membranes principalement chargées de la production d'énergie ainsi que la régulation réactive des espèces d'oxygène, la signalisation cellulaire et le contrôle de l'apoptose. Certaines expériences ont montré qu'après exposition aux rayonnements ionisants, les teneurs mitochondriales sont modifiées et leurs fonctions sont affectées. C'est pourquoi nous sommes intéressés par l'étude des effets des rayonnements ionisants sur les mitochondries. À l'échelle microscopique, les simulations Monte-Carlo sont utiles pour reproduire les traces de particules ionisantes pour une étude approfondie. Par conséquent, nous avons produit des fantômes 3D de mitochondries à partir d'images microscopiques de cellules fibroblastiques. Ces fantômes ont été transformés de façon à être téléchargés dans Geant4 sous forme de mailles tessélisées et tétraédriques remplies d'eau représentant la géométrie réaliste de ces organites. Les simulations numériques ont été effectuées afin de calculer les dépôts d’énergie induits par des photons de 250 keV à l'intérieur de ces fantômes. Les processus électromagnétiques Geant4-DNA sont utilisés pour simuler les traces des électrons secondaires produits. Étant donné que les dommages groupés sont plus difficiles à réparer par les cellules, un algorithme spécifique est utilisé pour étudier le regroupement spatial des dégâts potentiels des rayonnements. En radiothérapie, il est difficile de donner une dose efficace aux sites de la tumeur sans affecter les tissus environnants sains. L'utilisation de nanoparticules d'or comme radio-sensibilisateurs semble être prometteuse. Leur coefficient d'absorption élevé augmente la probabilité d’interaction des photons et induit une dose tumorale plus importante lorsque ces particules sont absorbés de manière préférentielle dans les tumeurs. Puisque l'or a un nombre atomique élevé, les électrons Auger sont produits en abondance. Ces électrons ont une portée plus faible que les photoélectrons, ce qui leur permet de déposer la majeure partie de leur énergie près de la nanoparticule, ce qui augmente la dose locale. Nous avons étudié l'effet radio-sensibilisant des nanoparticules d'or sur le fantôme des mitochondries. L'efficacité de cette méthode dépend du nombre, de la taille et de la répartition spatiale des nanoparticules d'or. Après exposition aux rayonnements ionisants, des espèces réactives d'oxygène sont produites dans le milieu biologique qui contient une quantité d'eau abondante. Dans cette étude, nous simulons les espèces chimiques produites à l'intérieur du fantôme des mitochondries et leur regroupement est estimé. La distribution spatiale des produits chimiques et leur évolution avec le temps et par la suite analysée au moyen d’algorithme spécifique de traitement de données. / In the field of radiobiology, damage to nuclear DNA is extensively studied since it is considered as a sensitive target inside cells. Mitochondria are starting to get some attention as sensitive targets as well since they control many functions important to the cell’s survival. They are double membraned organelles mainly in charge of energy production as well as reactive oxygen species regulation, cell signaling and apoptosis control. Some experiments have shown that after exposure to ionizing radiation the mitochondrial contents are altered and their functions are affected. That is why we are interested in studying the effects of ionizing radiation on mitochondria. At the microscopic scale, Monte Carlo simulations are helpful in reproducing the tracks of ionizing particles for a close study. Therefore, we produced 3D phantoms of mitochondria starting from microscopic images of fibroblast cells. These phantoms are easily uploaded into Geant4 as tessellated and tetrahedral meshes filled with water representing the realistic geometry of these organelles. Microdosimetric analysis is performed to deposited energy by 250keV photons inside these phantoms. The Geant4-DNA electromagnetic processes are used to simulate the tracking of the produced secondary electrons. Since clustered damages are harder to repair by cells, a clustering algorithm is used to study the spatial clustering of potential radiation damages. In radiotherapy, it is a challenge to deliver an efficient dose to the tumor sites without affecting healthy surrounding tissues. The use of gold nanoparticles as radio-sensitizers seems to be promising. Their high photon absorption coefficient compared to tissues deposit a larger dose when they are preferentially absorbed in tumors. Since gold has a high atomic number, Auger electrons are produced abundantly. These electrons have lower range than photoelectrons enabling them to deposit most of their energy near the nanoparticle and thus increasing the local dose. We studied the radio-sensitizing effect of gold nanoparticles on the mitochondria phantom. The effectiveness of this method is dependent on the number, size and spatial distribution of gold nanoparticles. After exposure to ionizing radiation, reactive oxygen species are produced in the biological material that contains abundant amount of water. In this study, we simulate the chemical species produced inside the mitochondria phantom and their clustering is estimated. We take advantage of the Geant4-DNA chemistry processes libraries that is recently included in the Geant4.10.1 release to simulate the spatial distribution of the chemicals and their evolution with time.

No description available.

In recent years, archaeogenetic studies have been widely discussed in popular media and they have raised many questions, especially regarding cultural identity and ethnicity. This thesis discusses reconstructions based on ancient human remains and how they are related to the current academic hegemony and political circumstances in Europe. People of Britain have reacted particularly strongly to the reconstruction of the Cheddar Man, exhibited in the Natural History Museum in London. Based on this and few other reconstructions of ancient individuals, the ethical issues behind human reconstructions are analyzed and how museums and popular media as the public spaces displaying these pieces of art should deal with such issues as cultural heritage, human origins, and identity. / Under de senaste åren har arkeogenetiska studier diskuterats allmänt i populära media och de har väckta väckts många frågor speciellt kring kulturell identitet och etnicitet. Denna studie diskuterar rekonstruktioner baserat på forntida mänskliga kvarlevor och hur de är relaterade till den nuvarande akademiska hegemonin och den politiska omständigheter i Europa. Människor i Storbritannien har reagerat särskilt starkt på rekonstruktionen av Cheddar-mannen, utställd i ”Natural History Museum” i London. Med utgångspunkt i denna och ytterligare några rekonstruktioner av forntida individer analyseras etiska frågor bakom mänskliga rekonstruktioner och hur museer och populära medier ska hanterar frågor om kulturarv, mänskligt ursprung och identitet.

L’objectif de cette thèse est d’utiliser la géochimie des spéléothèmes à travers une étude multi-proxy afin de reconstituer des changements environnementaux et climatiques dans le Sud-Ouest de l’Europe au cours de l’Holocène. Ce travail basé sur trois sites répartis entre l’Espagne et la France couvre les 14 000 dernières années. Cette région du sud-ouest de l’Europe, située à la confluence des hautes et des basses latitudes en fait une région particulièrement sensible à la fois à l’influence climatique de la région Nord-Atlantique mais également des régions Méditerranéenne et subtropicales Africaines et Asiatiques. Ce contexte particulier permet d’étudier idéalement l’impact des différents mécanismes climatiques agissant sur les modifications de son environnement. La répartition des sites d’étude a pour but de comparer les sites sous influence majeure Atlantique (Candamo, Nord Espagne), Méditerranéenne (Salamandre, SE France) ou sous influence mixte (Nerjà, sud Espagne). La compréhension des comportements géochimiques d’éléments clés, a constitué la première partie de cette étude. Après avoir établi un cadre temporel bien contraint (14C, U/Th), la géochimie élémentaire (éléments traces et terres rares) a été couplée à l’étude isotopique (87Sr/86Sr, d18O, d13C). Le rapport 87Sr/86Sr traditionnellement utilisé comme traceur de sources du Sr a été couplé à l’étude des variations élémentaires des éléments alcalins (Li, Rb, Cs) afin de déterminer des changements de sources des éléments (roche-mère ou de sol) dans les spéléothèmes. Le comportement de ces alcalins s’est également révélé lié à des modes de transports différents (particulaire, dissous ou liés à des complexes organiques) et l’utilisation du d13C et des terres rares (fractionnement terres rares légères et terres rares lourdes et anomalie en cerium) a permis de confirmer ou non ces hypothèses. La deuxième partie de ce travail a été d’appliquer ces mécanismes géochimiques à la détermination des processus hydrologiques et environnementaux et de les replacer dans le cadre climatique propre à chaque site d’étude. Ainsi, les éléments alcalins (Li, Rb, Cs) se sont révélés de bons indicateurs de phénomènes d'altération pouvant être liés à des changements climatiques (comme la transition entre le Bölling-Alleröd et le Younger-Dryas dans le site de la Salamandre), et/ou environnementaux (période de déforestation ou de mise en place de végétation à l’Holocène moyen dans le cas du site de Nerjà ou de Candamo). Ces événements pouvant donc se dérouler en contexte très différents (climat sec, déforestation, apports détritiques en climat humide par lessivage), le couplage à d’autres proxis est alors nécessaire pour préciser les conditions d'enrichissement de ces éléments alcalins. / The purpose of this thesis is to use speleothem geochemistry through a multi-proxy study to reconstruct environmental and climatic variations in southwestern Europe during the Holocene. This work, based on three sites distributed between Spain and France, covers the last 14,000 years. Due to its location at the confluence of the high and low latitudes, this region of south-western Europe is especially sensitive to both the influence of the North Atlantic climate but also the Mediterranean and subtropical African and Asian climate. This particular context allows to study ideally the impact of the different climatic mechanisms driving the modifications of its environment. The choice of the study sites’ distribution aims to compare sites with main Atlantic influence (Candamo, N Spain), Mediterranean (Salamandre cave, SE France) and mixt one (Nerjà, S Spain). The understanding of geochemical behavior was the first part of this study. After the establishment of a chronological frame (14C, U/Th), elemental geochemistry (trace elements and rare earth elements) and isotopic (87Sr/86Sr, d18O, d13C) was coupled. The 87Sr/86Sr isotope ratio, traditionally used as a source tracer for Sr, has been coupled to the study of elementary variations of alkali elements (Li, Rb, Cs) in order to determine changes in the contribution of bedrock and soil in speleothems. The behavior of these alkalis has also been shown to be related to different modes of transport (particulate dissolved or bound to organic complexes) and the use of d13C and rare earths (light rare earth and heavy rare earth fractionation and cerium anomaly) made it possible to confirm or not these hypotheses. The second part of this work was to apply these geochemical mechanisms to the determination of the hydrological and environmental processes and to place them in the specific climatic context of each study site. Thus, the alkali elements (Li, Rb, Cs) have proved to be good indicators of weathering phenomena that may be related to climate change (such as the transition between Bölling-Alleröd and Younger-Dryas in the Salamandre site), and/or environmental changes (period of deforestation or establishment of vegetation in the Middle Holocene in the case of the sites of Nerjà or Candamo). These events can thus take place in very different contexts (dry climate, deforestation, detrital inputs during wet climate by leaching) the coupling to other proxis is then necessary to specify the conditions of enrichment of these alkali elements.

Keywords: Historical reconstitution ̶ Entertainment ̶ Attraction ̶ World Exhibitions ̶ Prague ̶ Budapest ̶ Paris Abstract: The circulation of a historical entertainment - the reconstructions of the 'Old cities' - during the world Exhibitions at the end of the 19th century constitutes the heart of this project. Combining imperial, national and local scales, these 'Old cities' exploit several dynamics. First, these historic entertainments resulted from the restructuring of the Western and Central European empires. Indeed, the permanent injunction of national questions - here Czech and Hungarian - into the Austro-Hungarian empire and the expansion with a universalist aim of the French empire interfered within the construction of the 'Old cities' and their educational vocations. However, these imperial and global dimensions came into reaction with national and local scales due to the promotion of local products - architectural, commercial - serving the cause of the host nation. Thus, the various adaptations of 'Old city' recorded the materialization of collective memories fabricated to correspond to the challenges of the re-composition of empires and national agendas. These time capsules, fixing the past of the host city for one or several centuries, were like commercial attractions with educational purposes....

<p>3D character modeling is a crucial process of asset creation in the entertainment industry, particularly for animation and games. A fully automated pipeline via sketch-based 3D modeling (SBM) is an emerging possibility, but development is stalled by unrefined outputs and a lack of character-centered tools. This thesis proposes an improved method for constructing 3D character models with minimal user input, using only two sketch inputs  i.e., a front and side unshaded sketch. The system implements a deep convolutional neural network (CNN), a type of deep learning algorithm extending from artificial intelligence (AI), to process the input sketch and generate multi-view depth, normal and confidence maps that offer more information about the 3D surface. These are then fused into a 3D point cloud, which is a type of object representation for 3D space. This point cloud is converted into a 3D mesh via an occupancy network, involving another CNN, for a more precise 3D representation. This reconstruction step contends with non-deep learning approaches such as  Poisson reconstruction. The proposed system is evaluated for character generation on standardized quantitative metrics (i.e., Chamfer Distance [CD], Earth Mover’s Distance [EMD], F-score and Intersection of Union [IoU]), and compared to the base framework trained on the same character sketch and model database. This implementation offers a  significant improvement in the accuracy of vertex positions for the reconstructed character models. </p>