L'imaginaire de la fin évolue et s'actualise sans cesse, au gré du temps. Chez Douglas Coupland et Chuck Palahniuk, il se conjugue au singulier. La fin est intime, personnelle, elle ne concerne que le sujet, et lui seul. Néanmoins, elle interpelle les mêmes traits intrinsèques à tout imaginaire de la fin. La fin est transitive, elle est achèvement d'une chose et commencement d'une autre. Le temps de la fin, quant à lui, est toujours aussi harassant à négocier: passé, présent, futur cohabitent difficilement. Enfin, devant tant de désordres, la langue et l'imaginaire sont à leur tour happés par la confusion. À ces trois constantes s'en ajoute une quatrième, à l'œuvre autant dans Generation X que dans Choke: une sursollicitation de l'imaginaire qui provoque un brouillage important dans la perception du réel. Récits de la fin, Generation X et Choke sont aussi des romans du renouveau. S'ils disent que le monde menace l'individualité du sujet et qu'il est responsable des graves dysfonctionnements qu'il connaît, les romans de Coupland et Palahniuk nous disent aussi que l'homme peut être sauvé, s'il le désire. Il n'en tient qu'à lui. Résultat d'une clairvoyance du monde, d'une amère déception, puis façon de fabriquer du sens, la fin chez eux ne renvoie non pas à une fin du monde, à sa clôture, mais bien à son renouvellement, subjectif. Réaction, elle permet la survie, objet de pensée, elle incite à la perdition. Car si l'homme peut renaître, son monde et son imaginaire, eux, sont voués au désordre. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Coupland, Palahniuk, Fin, Imaginaire, Temps.

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<p>The teleost zebrafish (danio rerio) has a highly elevated regenerative capacity compared to mammals, with the ability to quickly and correctly regenerate complex organs such as the fin and the heart following amputation. Studies in other highly regenerative systems suggest that regenerative capacity is directly related to the homeostatic demands of a given tissue, such as high basal levels of cell turnover or the ability to modify tissue size in response to homeostatic changes. However, it is not known if this relationship is present in vertebrate tissues with blastema-based regeneration. To test this idea, we investigated whether markers associated with regeneration are expressed in uninjured zebrafish tissues, and if treatments that block regeneration also lead to homeostatic defects over long periods.</p><p>We found that regenerative capacity is generally required for homeostasis in the fin, as multiple genetic treatments that block regeneration also led to a degenerative loss of distal fin tissue in uninjured animals. In addition, we found that there is extensive cell turnover in the distal fin tissues, accompanied by expression of critical effectors of blastemal regeneration. Both cell proliferation and gene expression were sensitive to changes in Fgf signaling, a factor that is critical for fin regeneration.</p><p>In the heart, we found that although there is little cell turnover in uninjured adult animals, the zebrafish heart can undergo rapid, dramatic cardiogenesis in response to animal growth. These growth conditions induce cardiomyocyte hyperplasia similar to regeneration, and induce gene expression changes in the epicardium, a tissue that is critical for cardiac regeneration. We find that the epicardium continually contributes cells to the uninjured heart, even in the absence of cardiac growth. If this contribution is prevented via a long-term block of Fgf signals, scarring can result, indicating that continual activity of epicardium derived cells (EPDCs) is critical for cardiac homeostasis. We have generated reagents that allow us to visualize EPDCs, and find that they contribute cardiac fibroblasts and perivascular cells during rapid cardiac growth. Uncovering the fate of EPDCs during cardiac homeostasis and regeneration will allow us to better understand their function, and may lead to the development of regenerative therapies for human cardiovascular diseases.</p> / Dissertation

<p>Vertebrates like urodele and teleost have an enhanced capacity for regeneration, when compared to mammals. Recently, the teleost zebrafish (Danio rerio) has become a popular model for studying regenerative events, due to the ability to regenerate multiple organs such as the fin and the heart, and the diverse genetic approaches available for functional studies. In my thesis studies, I have used the zebrafish caudal fin as a model system to understand molecular and cellular mechanism of appendage regeneration. </p><p>Pharmacological and genetic studies have revealed that Fgf signaling is important for appendage regeneration. To dissect the mechanism of Fgfs during zebrafish fin regeneration, lab colleagues and I have generated and utilized transgenic animals in which Fgf signaling can be experimentally increased or decreased. Through these transgenic studies, I found that position-dependent Fgf signaling directs regenerative growth and blastemal proliferation. Proximally-amputated fin regenerates grow at higher rates than the distally-amputated, owing to position-dependent amounts of Fgf activity. Further studies using new transgenics have provided an understanding of mechanisms by which Fgfs influence epidermal regulation of the blastema. Loss- and gain-of-function studies of Fgfs reveal that Fgf signaling both positively and negatively regulated shh expression in the epidermis to maintain blastemal function.</p><p>During the fin regeneration process, pigmentation pattern is re-established as along with bone structures and connective tissues. While the lineage of the blastema is not precisely clear, pigment cells in the fin regenerates are thought to be derived from melanocyte stem cells. Therefore, melanocyte regeneration is an informative system to understand the mechanism underlying regulation of adult stem cells during regeneration. As part of my thesis studies, we generated transgenic animals in which ectopic Ras expression can be experimentally induced. Transgenic studies, combined with pharmacological approaches, have revealed that Ras controls self-renewal of melanocyte stem cells during fin pigment regeneration.</p> / Dissertation

This dissertation provides a detailed description of the research work completed on fin staged heat exchangers. The effects of staging fin on the frosting performance of heat pump evaporators and the whole heat pump system have been studied experimentally and theoretically. Frost degrades the performance of fin-and-tube outdoor coils as well as the whole heat pump system. The objective of the experimental part of this study was to investigate the effects of the staging fin on the frost/defrost performance of heat pump outdoor coils under different operating conditions. To accomplish this objective, a series of frosting tests was conducted on an off-the-shelf heat pump system with five (three two-row and two three-row) evaporators over a range of outdoor temperatures and humidities and a range of airflow rates typical of those found in residential sized heat pumps. Performances of the heat pump unit with baseline or fin staged outdoor coils at either frosting or steady-state test conditions are compared and analyzed. Experimental data showed that for a given tworow heat pump outdoor coil operating at the standard ANSI/ASHRAE 35 °F (1.7 °C) frosting conditions, fin staging increased cycle time and COP. There was a small decrease in peak capacity at lower initial airflow rates. At a lower temperature of 28 °F (2.2 °C), cycle time continued to be enhanced with fin staging, and cyclic COP was within 5% of the base case when fin staging was used. In the second step of this work, an analytical model to simulate the performance of both the baseline and fin staged heat pump coils under frosting conditions was developed based on fundamental heat and mass transfer principles. The transient performance of the frosted evaporator was analyzed with the quasi-steady state approach. The section-by-section evaluation scheme was combined with the tubeby- tube approach to model the mass transfer process in the frost formation module. The two-dimensional fin surface was divided into a number of parallel non-overlapping sections. Each of the sections was the calculation unit for the mass transfer. Methods for calculating the airside heat transfer coefficient and friction factor were developed and applied to the simulation model of the fin staged coil. To verify the validity of the frosted evaporator model, the frosting performance of three two-row coils at the same test conditions was simulated and compared with experimental data. The frosted evaporator model appeared to provide satisfactory simulation of the fin-and-tube heat exchanger during the frost buildup process. Comparisons with the test data indicated that the model could capture the trends of the coil capacity, pressure drop, airflow and frost growth. The model also provided a variety of other simulation results including frost mass accumulation, air velocity inside coil, air and refrigerant outlet state, and so on. Overall, the numerical results were in reasonable agreement with the test data under different frosting operation conditions.

Magnetic confinement fusion has the potential to provide a nearly inexhaustible source of energy. Current fusion energy research projects involve conceptual "Tokamak" reactors, inside of which contaminants are "diverted" along magnetic field lines onto collection surfaces called divertor plates. Approximately 15% of the reactor's thermal power is focused on the divertor plates, creating a need for an effective cooling mechanism. Current extrapolations suggest that divertor plates will need to withstand heat fluxes of more than 10 MW/m2. The cooling mechanism will need to use a coolant compatible with the blanket system; currently helium, and use a minimal fraction of the reactor's available pumping power; ie: will need to experience minimal pressure drops. A leading cooling concept is the Helium Cooled Flat Plate Divertor (HCFP). This thesis experimentally examines four variations of the HCFP. The objectives are to: 1. Experimentally determine the thermal performance of the HCFP with a hexagonal pin-fin array in the gap between the impinging jet and the cooled surface over a range of flow rates and incident heat fluxes; 2. Experimentally measure the pressure drop associated with the hexagonal pin-fin array over a range of flow conditions; 3. Determine and compare the thermal performance of and pressure drop associated with the HCFP for two different slot widths, 0.5 mm and 2 mm over a range of flow rates and incident heat fluxes; 4. Compare the performance of the HCFP with a hexagonal pin-fin array with that of the HCFP with a metal-foam insert and the original HCFP; 5. Provide an experimental data set which can be used to validate numerical models of the HCFP design and its variants. 6. Analytically determine the maximum heat flux which the HCFP can be expected to withstand at theoretical operating conditions in the original and pin-fin array configurations.

Grid fins (lattice fins) are used as a lifting and control surface for highly manoeuvrable missiles. Grid fins also find their applications for air-launched submunitions. The main advantages are its low hinge moment requirement and good high angle of attack performance characteristics. Two dimensional analysis has been carried out using linear and shock-expansion theo- ries. The results indicate that above certain depth-to-height ratio, (called critical depth-to-height ratio,) the local normal force becomes negative due to shock reflection from the opposite side. Hence, depth (chord) for grid fin cell should not exceed a critical value. A prediction method has been developed for the estimation of aerodynamic character- istics of grid fin-body combinations at supersonic Mach numbers based on shock-expansion theory. Body upwash theory has been used for the effect of body; method of images has been used for carry-over forces onto the body. Empirical relation has been used for the modelling of separated body vortices and their effect on the leeward side fins. The method has been validated with experimental results for three configurations. The comparison is good for individual fin characteristics as well as overall characteristics for all the cases at higher supersonic Mach numbers. For lower supersonic Mach numbers at higher angles of attack, the prediction deviates from experiment. The reason for the deviation is due to shock detachment and shock reflection from opposite side, which is not modelled in the present method. Vortex lattice method has been used for prediction of linear aerodynamic character- istics of grid-fins at subsonic Mach numbers. Empirical relation based on trends from available experimental data has been used for the non-linear effect. The method has been validated with experimental results for several configurations without and with control surface deflections. The predicted aerodynamic characteristics compare well with experimental results for all the cases and the difference is within 15%. Based on the subsonic and supersonic analytical methods, a prediction code for the aerodynamic analysis of configuration with grid fins has been developed. Flow field computations inside isolated cells have been carried out using CFD code, PARAS-3D. Effects of depth-to-height ratio, web thickness, web leading edge angle and cell width-to-height ratio have been studied. Increase in thickness reduces the critical depth and increases the normal force. This increment in normal force is due to shock wave formation at the expansion side and its interaction with the opposite side. Effect of cell cross sectional shape has been studied using inviscid computation over isolated cells. Square, right triangular, equilateral triangular and hexagonal cross sections have been considered for this study. The normal force for square cell at zero roll is higher compared to 45 deg roll (diamond shape). Triangular cells show large variation in normal force with roll orientation due to large variation in projected area with roll angle. To compare the characteristics of different cross sectional cells, the normal force is normalised with respect to total internal web area. The comparison shows that the hexagonal cell gives maximum normal force and right triangular cell gives the minimum. Packaging efficiency of different cross sections is analysed by normalising the normal force with frontal area. The results show that triangular cells are preferred for packaging efficiency. Viscous flow computations over complete configuration have been carried out using FLUENT. GAMBIT has been used for geometry definition and grid generation. Hexahedral finite volumes are used to generate the grids including the nose region. Flow computations have been carried out at supersonic Mach numbers. To reduce the compu- tational time, Flow computations upto 0.5 calibre ahead of grid fin have been carried out with body-alone configuration. Flow over the fin-body section has been computed sep- arately taking the inlet pressure condition from the body-alone computed results. This procedure has reduced the grid size to around 1/5th and the computations converged faster due to imposition of converged solution at the pressure inlet. The computed results on the body show that the Flow separation occurs on the lee- ward side of the body and formation of separated vortices. The comparison of pressure distribution on the body with experiment is good. Flow computations over the fin-body section have been carried out at different Mach numbers and angles of attack. The computed normal force coefficient on the horizontal fin compares well with experimental data. Computations with fin deflection of -15 deg have also been carried out and the computed results are within 10% of the experimental data. Flow computations over another grid fin configuration have been carried out at dif- ferent roll angles. The comparison of individual fin force and overall normal force and pitching moment coefficients with experiment is good. The comparison demonstrates the capability of prediction methods as well as CFD in analysing aerodynamic performance of grid fin configurations.

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My dissertation departs from the idea that horizontal kinship, in particular the sibling bond, has largely been overlooked by criticism of 19th century Argentine literature. Works on the foundational mid-century narratives concentrate on allegorical heterosexual unions, while those of the late century primarily deal with the failed marriages of naturalist fiction. I argue that in viewing the fictional family as a vertical, genealogical structure, these texts often fail to consider what Pierre Bourdieu calls "practical kinship". Also, in primarily focusing on the novel, they overlook the minor genres to which women were traditionally limited, such as pedagogical texts, as well as private or semi-private writing like the diary and the memoir, in which sibling relations are more prominent. This project, in contrast, takes a politically engaged, socially influential family of writers, rather than a fictional representation, as the framework for analyzing the social, cultural, and political shifts of the turn of the century in Argentina (1890-1910). Focusing on the work of two proto-feminist sisters, Delfina and Julia Bunge, and a closeted homosexual brother, Carlos Octavio Bunge, I study the dynamic relationship between these siblings, reading a wide range of their public and private texts. In dialogue with naturalist novelists and positivist essay writers, la familia Bunge challenges the conventional view that the upper class saw the traditional criollo family unit as the last bastion of stability in the face of sexual and class "inversion" by themselves questioning normative gender roles, complicating compulsory heterosexuality, and performing the gaps in the hegemonic division of public and private space. I analyze siblinghood as a dynamic actor in shaping the literature, culture, and politics of the turn of the century, underscoring the role of relational subjectivities in forming notions of gender, sexuality, citizenship, and mutual intelligibility. / text

In this study, I examine how firms change their tax avoidance and financial reporting following large tax settlements. I find that firms decrease tax avoidance following large settlements and this effect is concentrated among firms under-reserved for the settlement for financial accounting purposes. Additionally, my results suggest firms learn from tax examination resolutions in a way that affects their financial reporting over the tax account. Finally, I find that the effect of large settlements also spills over to firms within the same auditor network. This study provides context to the tax authority's efficacy in deterring tax avoidance and highlights its role in the financial reporting process.