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Thesis (Ph.D.)--McMaster University, 2005. / Supervisors: M.A. Elbestawi, G.M. Bone. Includes bibliographical references (leaves 117-122).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 131-154).

<p>The aim of this study was to understand injury mechanisms behind fractures of the upper extremities in car accidents. Volvo Car Corporation initiated this project based on the fact that no safety system today focuses on preventing injuries to the upper extremity. A literature study was undertaken focusing on the basic anatomy of the upper extremity, different fracture types and fracture mechanisms. Three subsets, from 1998 – January 2009, were selected from Volvo’s statistical accident database: 1) all occupants involved in an accident 2) all occupants with a MAIS2+ injury 3) all occupants with an upper extremity fracture. These subsets were used in a comparison, using frequency analyses. The comparison analysis showed that frontal impact is the dominating accident type for all three subsets. The comparison analysis also indicated that the risk for upper extremity fractures follows the pattern of MAIS2+ injury risk. An in-depth study using 92 selected cases, including 80 occupants, was also performed. All available information, such as medical records, questionnaires completed by the occupants and photographs from the accident scene was collected and analysed. The analysis of the in-depth study, together with knowledge retrieved from the literature study, resulted in six different mechanism groups that were used to categorise fractures. The groups were then analysed individually in regard to accident type and fractured segment of the upper extremity. Analysis of the mechanism groups showed that frontal impact is the dominating accident type in these subsets as well. It could also be seen that the fractures occurring in the in-depth study are quite evenly distributed along the upper extremities. Upper extremity injuries are relatively infrequent in car accidents but may result in long-term disability, including chronic deformity, pain, weakness and loss of motion. More attention is therefore necessary in order to develop a safer environment for car occupants.</p>

Graduation date: 1997

Fiscal federalism is meant to benefit from both the advantages of centralization and decentralization in public revenues and expenditures, the optimal allocation of competencies between levels of governement depending on the nature of revenues, public goods or services. For historical, political or practical reasons, this optimal allocation is not always attainable. Therefore, fiscal federalism may raise new issues in efficiency or equity, in the form of spill-over effects, harmful fiscal competition or fiscal imbalance. To tend to the optimum, it is necessary to evaluate the extent of inefficiencies or inequities and to design corrective mechanisms in order to minimize them. This thesis adopts such an approach in four different situations. First, we measure empirically and dynamically the presence of fiscal competition between Belgian municipalities. The analysis reveals the existence of fiscal competition, but with a rather slow pace of adjustment of taxe rates over time. This pace depends on the mobility of tax bases and on the similarity of neighboring municipalities with respect to some socio-economic characteristics. Second, we evaluate the effects of the Belgian fiscal equalization mechanism on equity. This analysis shows the existence of a poverty trap at the level of regions and proposes a range of solutions, inspired by equalization mechanisms applied in other federal States. Third, we analyse the case of multiple States emitting multiple pollutants where a trade-off exists between producing goods and minimizing pollution. We propose a form of inter-State transfers such that all States adopt a behaviour leading to the collective optimum. To be sustainable, the collective optimum must be individually rational. We show that this condition is respected with the proposed transfer formula. Fourth, we examine the case of harmful fiscal competition between two countries differing in size, the small country being seen as a fiscal heaven. In order to reach the collective optimum, fiscal cooperation is needed. To convince the tax heaven to cooperate, a specific formula of transfers between the large and the small country is proposed, such that both countries are better off. / Le fédéralisme fiscal a pour objectif de bénéficier à la fois des avantages de la centralisation et des avantages de la décentralisation des revenus et dépenses publiques. La répartition optimale des compétences entre différents niveaux de pouvoir est déterminée par la nature des revenus, dépenses et biens et services publics. Pour des raisons historiques, politiques ou pratiques, cette répartition optimale n'est pas toujours accessible. En conséquence, les avantages du fédéralisme fiscal peuvent s'accompagner de problèmes d'efficacité ou d'équité sous la forme d'effets de débordement, de concurrence fiscale dommageable ou de déséquilibre fiscal. Pour tendre vers l'optimum, il convient dès lors d'évaluer l'ampleur des inefficacités et inéquités et de concevoir des mécanismes correctifs pour les atténuer. Cette thèse applique cette démarche à quatre situations particulières. Premièrement, nous mesurons la présence de concurrence fiscale entre les communes belges, de façon empirique et dynamique. L'analyse met en lumière l'existence d'une concurrence fiscale certaine, mais avec une vitesse d'ajustement des taux de taxation relativement faible dans le temps. Cette vitesse d'ajustement dépend de la mobilité des bases imposables et de la similitude des communes voisines en termes de caractéristiques socio-économiques. Deuxièmement, nous évaluons les effets redistributifs et incitatifs du mécanisme belge de péréquation financière. Cette analyse démontre la présence d'un effet de « piège à pauvreté » au niveau des Régions et propose une série de solutions pour y remédier, en s'inspirant de mécanismes étrangers. Troisièmement, nous analysons le cas de multiples Etats émettant de multiples polluants, dans un contexte où un arbitrage doit être effectué entre la production de biens et la minimisation de la pollution. Nous proposons une forme de transferts à appliquer entre Etats de sorte que tous les Etats sont amenés à adopter un comportement menant à l'optimum collectif. Pour être soutenable, l'optimum collectif doit être individuellement rationnel. Nous démontrons que la formule proposée respecte cette condition. Quatrièmement, nous examinons le cas d'une concurrence fiscale dommageable entre deux pays différents en taille, où le petit pays peut être considéré comme un paradis fiscal. Afin d'atteindre l'optimum collectif, une coopération fiscale est nécessaire. Afin de convaincre le paradis fiscal de coopérer, une forme spécifique de transferts entre le grand et le petit pays est proposée, de sorte que tous deux préfèrent coopérer.

Brightness judgments are a key part of the primate brain's visual analysis of the environment. There is general consensus that the perceived brightness of an image region is based not only on its actual luminance, but also on the photometric structure of its neighborhood. However, it is unclear precisely how a region's context influences its perceived brightness. Recent research has suggested that brightness estimation may be based on a sophisticated analysis of scene layout in terms of transparency, illumination and shadows. This work has called into question the role of low-level mechanisms, such as lateral inhibition, as explanations for brightness phenomena. Here we describe experiments with displays for which low-level and high-level analyses make qualitatively different predictions, and with which we can quantitatively assess the trade-offs between low-level and high-level factors. We find that brightness percepts in these displays are governed by low-level stimulus properties, even when these percepts are inconsistent with higher-level interpretations of scene layout. These results point to the important role of low-level mechanisms in determining brightness percepts.

Primary cultures of stromal-vascular (S-V) cells from adipose tissue were used to investigate the regulation of preadipocyte development. Differentiation of S-V cells was found to be under hormonal control. Insulin and glucocorticoids are essential for S-V cell differentiation in culture. S-V cells from both newborn and mature pig adipose tissue and sera from both ages were used to examine the effect of age on preadipocyte development. S-V cells from newborn pigs replicated faster and appeared more responsive to serum borne factors influencing S-V cell growth and development in culture. Serum source (newborn vs mature) did not affect differentiation of S-V cells from newborn or mature pig adipose tissue. When sera from fed or fasted pigs were used to culture newborn pig S-V cells, fasted pig sera stimulated greater differentiation and decreased cell replication as indicated by DNA content of rat S-V cell culture. Lean pig serum compared to obese pig serum, increased differentiation activity in culture of S-V cells an effect which may be influenced by sex. When sera from rat and pig were subjected to gel filtration fractionation on Sephacryl S-200 column, the elution profiles of both sera were similar. Rat serum contained six additional peaks (280 nm) not present in pig serum. Rat serum fraction two (apparent molecular size 67-150 kD) promoted greater differentiation of S-V cells than other rat serum fractions or pig serum fraction two. Fraction three (apparent molecular size 17-43 kD) of both sera inhibited differentiation and lipid filling in cultures of S-V cells but only rat fraction three promoted cell proliferation. Rat and pig S-V cells have different morphology when differentiated. Differentiated rat S-V cells appeared as individual cells when cultured in serum free or serum supplemented medium while differentiated pig S-V cells appeared as individual cells in serum free medium and as a tight cluster of cells in serum supplemented medium. Both cells responded differently to sera obtained from pigs of differing ages and development of rat S-V cells was influenced by anatomic site. / Graduation date: 1992