Les propriétés microvasculaires de la moëlle osseuse (MO) sont mal connues chez l’être humain. L’IRM de perfusion en permet une évaluation quantitative non invasive. La hanche a été choisie, car elle est la cible de pathologies fréquentes et handicapantes, qu’il est nécessaire de diagnostiquer plus précocement telle la coxarthrose. Nous avons d’abord implémenté une séquence IRM volumique à voxels isotropiques, avec une couverture large et une résolution spatiale élevée. Celle-ci a ensuite permis l’étude d’une série de 60 patients âgés de 18 à 60 ans, sans antécédent de pathologie osseuse et présentant une MO d’aspect normal en IRM. Les paramètres de perfusion semi-quantitatifs et pharmacocinétiques ont été mesurés dans 15 régions d’intérêt chez chaque patient. Tous les paramètres de perfusion diffèrent entre les zones de MO rouge et de MO jaune. La perfusion est différente entre les MO acétabulaire (squelette axial) et fémorale intertrochantérienne (squelette appendiculaire). Plusieurs paramètres sont corrélés de manière négative à l’âge. Plusieurs paramètres sont différents entre les hommes et les femmes. La perfusion de la tête fémorale est hétérogène, probablement en raison de l’exposition aux contraintes mécaniques. Les paramètres Ktrans, Kep et TTP sont corrélés à l’indice de masse corporelle, ce qui suggère que l’obésité influence le métabolisme de la MO. Enfin, le tabagisme et l’hypercholestérolémie ont une incidence sur ces mêmes paramètres dans certaines zones. Ils pourraient donc être le reflet d’altérations de la microvascularisation osseuse. Ces travaux ouvrent de nouvelles perspectives de recherche sur la physiologie et la pathologie de la MO. / Bone Marrow (BM) microvascular properties are insufficently known in humans. Dynamic-Contrast Enhanced (DCE) MRI allows its non-invasive quantitative assessment. We concentrated on the hip because this joint is frequently affected by debilitating pathologies such as osteoarthritis. Their early diagnosis is a current medical challenge. We implemented a 3D DCE-MRI sequence with isotropic voxels, high spatial resolution and a large coverage. It was used in a study of 60 patients aged 18 to 60, with no previous history of bone disease and with normal-appearing BM on MR images. Semi-quantitative and pharmacokinetic parameters were measured in 15 regions of interest in each patient. All the parameters were different between red and yellow BM. Perfusion was different between acetabular (axial skeleton) and femoral intertrochanteric (appendicular skeleton) BMs. Several parameters were negatively correlated with age. Perfusion was different in men and women. The femoral head perfusion was heterogeneous, likely because of mechanical load exposure. Ktrans, Kep and TTP were correlated with body mass index. This suggests that obesity influences BM metabolism. Smoking and hypercholesterolemia influenced these same parameters in several zones. We hypothesized that these parameters might reflect BM microvascular aletrations. Our results open new research perspectives both in the physiology and pathology of BM.

Práce zkoumá původ a obsah ekonomického a účetního jevu zvaného goodwill. V textu pak kombinuje teoretické úvahy s praktickými aspekty účtování podle konkrétních účetních úprav. Stručně jsou v ní popsány současné úpravy podle IAS/IFRS, US GAAP a úprava v ČR. Dále se práce zabývá věcným obsahem goodwillu, popisem jednotlivých konsolidačních konceptů, odpisováním a testováním na pokles hodnoty, vztahem prvotního a nakoupeného goodwillu a vykazováním nehmotných aktiv obecně. Zvláštní kapitola je věnována daňovým souvislostem. Představeno je konsorcium Enhanced Business Reporting, zabývající se unifikovaným vykazováním tzv. nefinančních informací. V závěru se práce zabývá aktuálně připravovanou novelizací IFRS 3 a s ní souvisejícím konceptem totálního goodwillu.

Foi estudada a absorção da luz por partículas metálicas esferoidais, filmes metálicos finos e filmes metálicos finos cobertos com uma camada de material orgânico nas regiões espectrais do visível e do infravermelho. A dependência das características dos picos de absorção de luz por partículas metálicas para com a forma e o tipo de material foi analisada. Modelos para o estudo de filmes metálicos finos foram deduzidos, a aproximação por rede de dipolos foi escolhida e resultados obtidos com o uso desta teoria foram comparados com resultados experimentais e com resultados teóricos encontrados na literatura. Um modelo para o estudo de filmes metálicos cobertos com uma camada de material orgânico foi proposto e sua consistência e utilidade foram testadas. Computações foram efetuadas usando o programa Maple. / The absorption of light in the visible and infrared spectral regions by spheroidal metal particles, thin metallic films and thin metallic films covered with organic layers was studied. The dependence of the intensity and frequency of the peaks of absorption of light by metal particles with the shape and the kind of metal was studied. Models for the study of thin metallic films were deduced, the net dipole approximation is chosen and results obtained with it are compared with experimental results and with results obtained with a Maxwell-Garnett type theory. A model for the study of metallic films covered with organic layers was proposed and tested for consistency and utility. Computations were carried out using Maple.

Carbon dioxide enhanced oil recovery (CO2EOR) is a proven and available technology used to produce incremental oil from depleted fields. Although this technology has been used successfully onshore in North America and Europe, projects have maximised oil recovery and not CO2 storage. While the majority of onshore CO2EOR projects to date have used CO2 from natural sources, CO2EOR is now more and more being considered as a storage option for captured anthropogenic CO2. In the North Sea the lack of low cost CO2, in large volumes, has meant that no EOR projects have utilised CO2 as an injection fluid. However CO2EOR has the highest potential of all EOR techniques to maximise recovery from depleted UK oil fields. With the prospect of Carbon Capture and Storage (CCS) capturing large tonnages of CO2 from point source emission sites, the feasibility of CO2EOR deployment in the North Sea is high. This thesis primarily aims to address a number of discrete issues which assess the effectiveness of CO2EOR to both produce oil and store CO2. Given the fundamental shift in approach proposed in North Sea CO2EOR projects, the carbon balance of such projects is examined. Using a life cycle accounting approach on a theoretical North Sea field, we examine whether offshore CO2EOR can store more CO2 than onshore projects traditionally have, and whether CO2 storage can offset additional emissions produced through offshore operations and incremental oil production. Using two design scenarios which optimise oil production and CO2 storage, we find that that net GHG emissions were negative in both ‘oil optimised’ and ‘CO2 storage optimised’. However when emissions from transporting, refining and combusting the produced crude oil are incorporated into the life cycle calculations the ‘oil optimised scenario’ became a net emitter of GHG and highlights the importance of continuing CO2 import and injection after oil production has been maximised at a field. This is something that has not traditionally occurred. After assessing rates of flaring and venting of produced associated gas at UK oil fields it is found that the flaring or venting of reproduced CH4 and CO2 has a large control on emissions. Much like currently operating UK oil fields the rates of flaring and venting has a control on the carbon intensity of oil produced. Here values for the carbon intensity of oil produced through CO2EOR are presented. Carbon intensity values are found to be similar to levels of current UK oil production and significantly lower than other unconventional sources. As well as assessing the climate benefits of CO2EOR, a new assessment of CO2EOR potential in Residual Oil Zones (ROZ) is also made. ROZ resource, which is thought to add significant potential to both the oil reserves and CO2 storage potential in some US basins, is here identified in the North Sea for the first time. Based on the foundation of North Sea hydrodynamics study, this thesis identifies the Pierce field as a candidate ROZ field where hydrodynamic tilting of the oil water contact has naturally occurred leaving a zone of residual oil. To test the feasibility of CO2EOR in such a zone a methodology is presented and applied. Notably the study highlights that in this case study recoverable reserves from the ROZ may approach 20% of total field recoverable reserves and have the capability to store up to 11Mt of CO2. While highlighting the CO2EOR potential in the ROZ the thesis discusses the importance in expanding the analysis to quantify its importance on a basin scale. Discussion is also made on whether new resource identification is necessary in a mature basin like the North Sea. With CO2EOR being considered as a feasible option for storing captured anthropogenic CO2, it is important to assess the security of storage in CO2EOR. Using real geochemical and production data from a pilot CO2EOR development in Western Canada two approaches are used to assess the partitioning of CO2 between reservoir fluids through time. Using a number of correlations it is found that CO2 dissolution in oil is up to 7 times greater than in reservoir brine when saturations between the two fluids are equal. It is found that after two years of CO2 injection solubility trapping accounts for 26% of injected CO2. The finding that significantly more dissolution occurs in oil rather than brine indicates that CO2 storage in EOR is safer than in brine storage. However a number of factors such as the increase in oil/CO2 mobility due to CO2 injection is also discussed. The overall conclusion from the work is that CO2EOR in the North Sea has the potential to be an effective way of producing oil and storing CO2 in the North Sea. A number of design, operational and accounting factors are however essential to operate an exemplar CO2EOR project where low carbon intensity oil can be produced from a mature basin while storing large tonnages of captured anthropogenic CO2.

Changes in the productivity of temperate forests have important implications for atmospheric carbon dioxide (CO2) concentrations, and many efforts have focused on methods to monitor both gross and net primary productivity in temperate forests. Remotely sensed vegetation indices provide spatially extensive measures of vegetation activity, and the Enhanced Vegetation Index (EVI) has been widely linked to photosynthetic activity of vegetation. Networks of tree ring width (TRW) chronologies provide ground-based estimates of annual net carbon (C) uptake in forests, and time series of EVI and TRW may capture common productivity signals. Robust correlations between mean TRW and EVI may enhance spatial extrapolations of TRW-based productivity estimates, ultimately improving understanding of spatio-temporal variability in forest productivity. The research presented in this thesis investigates potential empirical relationships between networks of TRW chronologies and time series of Landsat EVI and Landsat-based phenological metrics in the Northeast United States. We hypothesized that mean TRW is positively correlated with mean monthly EVI during the growing season, EVI integrated over the growing season, and growing season length. Results indicate that correlations between TRW and EVI are largely not significant in this region. The complex response of tree growth to a variety of limiting climatic factors in temperate forests may decouple measures of TRW growth and canopy reflectance. However, results also indicate that there may be important lag effects in which EVI affects mean TRW during the following year. These findings may improve understanding of links between C uptake and growth of tree stems over large spatial scales.

Atualmente existem muitas evidências da presença de matéria escura no Universo. Estas motivaram a existência de vários experimentos para sua detecção. Entre os experimentos de detecção indireta de matéria escura, o PAMELA, o ATIC e o Fermi-LAT observaram recentemente excessos de elétrons e pósitrons no fluxo galáctico em relação ao esperado para estas partículas. Estes resultados podem ser explicados pela aniquilação de matéria escura com massas entorno a 1 TeV em nossa galáxia, com produção de léptons. No entanto, para tal, estas observações requerem um aumento na taxa de aniquilação relativa à esperada da produção térmica de matéria escura. Este aumento pode ser devido a existência de subestruturas de matéria escura no halo galáctico ou a mecanismos de interação, como o efeito Sommerfeld, que aumentam a seção de choque de aniquilação das partículas de matéria escura. Neste _ultimo caso, deve ocorrer também um aumento na taxa de neutrinos provenientes da aniquilação de matéria escura no núcleo da Terra. Neste trabalho, estimamos as taxas destes neutrinos e usamos os resultados finais do AMANDA-II e resultados recentes de IceCube para testar cenários genéricos que contemplam um aumento na seção de choque de aniquilação. Apresentamos os nossos resultados em função da seção de choque de interação da matéria escura com os núcleos multiplicada pela fração da aniquilação das partículas de matéria escura em neutrinos e, também em função de um fator genérico de boost que parametriza o aumento na seção de choque de aniquilação. Encontramos que modelos de matéria escura requerem fatores de boost da ordem O(100) ou mais e que se aniquilam significativamente em neutrinos são excluídos como explicação dos excessos leptônicos medidos. / Currently there are many evidences of the existence of dark matter in the Universe. These led to experimental dark matter searches and, among them, some indirect detection experiments, PAMELA, ATIC and Fermi-LAT, have recently observed excesses in the galactic flux of electrons and positrons relative to the expected flux of these particles. These results could be explained by dark matter, with masses of the order of 1 TeV, annihilating into leptons in our galaxy. However, in order for this to explain the mentioned excesses, it is required that the dark matter annihilation rate is greater than the implied rate assuming the expected dark matter thermal annihilation cross section. This greater rate could be due to the presence of dark matter substructures in the galactic halo or due to interaction mechanisms, such as the Sommerfeld effect, that enhance the dark matter annihilation cross section. In the latter case, an enhancement in the neutrino flux from annihilation of dark matter particles in the Earth nucleus should also occur. In this work, we use the final results of AMANDA-II and recent results of IceCube to probe generic enhancement scenarios. We present results as a function of the dark matternucleon interaction cross section weighted by the branching fraction into neutrinos, and as a function of a generic boost factor, which parametrizes the expected enhancement of the annihilation rate. We find that dark matter models that require boosts factors of O(100) or more and that annihilate mainly into neutrinos are excluded as a explanation for the observed leptonic excesses.

No description available.

Biophysical simulation can be an excellent complement to experimental techniques, but there are unresolved practical constraints to simulation. While computers have continued to improve, the scale of systems we wish to study has continued to increase. This has driven the use of approximate energy functions (force fields), compensating for relatively short simulations via careful structure preparation and accelerated sampling techniques. To address structure preparation, we developed the many-body dead end elimination (MB-DEE) optimizer. We first proved the MB-DEE algorithm on a set of PCNA crystal structures, and accelerated it on GPUs to optimize 472 homology models of proteins implicated in inherited deafness. Advanced physics has been clearly demonstrated to help optimize structures, and with GPU acceleration, this becomes a possibility for large numbers of structures. We also show the novel “simultaneous bookending” algorithm, which is a new approach to indirect free energy (IFE) methods. These first perform simulations under a cheaper “reference” potential, then correct the thermodynamics to a more sophisticated “target” potential, combining the speed of the reference potential with the accuracy of the target potential. Simultaneous bookending is shown as a valid IFE approach, and methods to realize speedups vs. the direct path are discussed. Finally, we are developing the Monte Carlo Orthogonal Space Random Walk (MC-OSRW) algorithm for high-performance alchemical free energy simulations, bypassing some of the difficulty in OSRW methods. This work helps prevent inaccuracies caused by simpler electrostatic models by making advanced polarizable force fields more accessible for routine simulation.

This study examined the fidelity of implementation by four Head Start teachers using the teaching strategies of constant time delay, enhanced milieu teaching, and system of least prompts with children with and without disabilities in an inclusive early childhood setting. The teachers worked with the researcher to determine appropriate skills to target for each teaching strategy. A multiple probe across behaviors design replicated across four teachers was used to determine the effects of teachers’ fidelity of implementation of evidence-based teaching strategies. The results showed that Head Start teachers could implement systematic teaching strategies with fidelity. The study also examined if children with and without disabilities can make progress towards their target skills. The results showed that children were able to make progress towards their target skills.

Although a mandate was given in an urban southern university for instructors in the Adult Professional Studies Program (APS) to begin transitioning their face-to-face courses to online curricula, few courses have been converted. The purpose of this case study was to determine APS instructors' perceptions of developing and transitioning face-to-face courses to an online format. Lewin's change theory and force field analysis provided the conceptual framework for this study. The research questions concerned the faculty's perceptions of developing and transitioning courses to an online format. A purposeful sample of fulltime and adjunct faculty, with different levels of expertise in online courses within the APS department was invited to participate. Semistructured interview data from these faculty (n = 9) - were analyzed manually using color coding to determine the needs and barriers for instructors transitioning their face-to-face courses to online curricula. According to the study findings, the APS faculty saw value in online education, but perceived many obstacles that keep them from fully investing into this type of instruction. 10 themes were identified through data analysis in this study. These themes were used to create a 3-day professional development (PD) project for faculty members in the APS to assist educators in creating appropriate innovations for teaching and learning in an online setting. Creating a comprehensive, 3-day PD training for APS staff and faculty that address barriers noted in the findings of the study and diverse learning opportunities created learning opportunities for nontraditional students in the APS.