Methods were developed for the determination of methylmercury in natural waters and sediments based on steam distillation and aqueous phase ethylation followed by gas chromatography-atomic fluorescence spectrometry. The methods were shown to be free from measurable artefactual methylation of inorganic mercury and offered improved sample throughput over existing methods. Improvements were made to existing methods for the determination of total mercury in biota, sediments and natural waters and dissolved mercury species in natural waters. These methods were applied to the study of mercury cycling in two remote field sites. The cycling of mercury species was studied in Lake Murray in Western Province, Papua New Guinea, which has been historically noted as a region of high mercury concentrations in fish. Concentrations of methylmercury and total mercury in the water column were found to be variable and consistent with non-contaminated lake systems. Concentrations of methylmercury and total mercury in the sediments were also found to be low, except for in the south of the lake, which was influenced by an intermittent supply of water and sediments with elevated mercury concentrations from the Strickland River. Methylmercury concentrations in the sediments were generally higher in the backwater areas due to littoral processes. The low concentrations of methylmercury in the sediments and waters were inconsistent with other systems previously studied in the northern hemisphere, showing a link between high mercury concentrations in fish and high concentrations of methylmercury in waters or sediments. Therefore, the biota of Lake Murray were studied in order to account for the differences between this and other systems. A study was conducted of the stable isotope ratios of carbon and nitrogen in biota from Lake Murray to elucidate key food-web interactions. This study revealed that the dominant carbon source for fish in the lake is plankton, although algae and macrophytes may also be involved in the food-web. The methylmercury bioaccumulation factors between trophic levels were similar to those measured in temperate systems of the northern hemisphere. The high concentrations of methylmercury, observed in piscivorous fish, were shown to be a consequence of the complex food-web and the number of trophic levels in the food-chains. The cycling of mercury species was studied in Lake Gordon and Lake Pedder in southwest Tasmania, which has recently been identified as being in a region of high mercury concentrations in trout and eels. The concentrations of total mercury were found to be reasonably uniform in the waters of both lakes, spatially and temporally. The concentrations of methylmercury in the waters were seasonally variable, and were consistently lower in Lake Pedder than in Lake Gordon. Dilution of methylmercury concentrations by precipitation direct to the lake surface, probably accounts for the most of the difference in methylmercury concentrations between the lakes. Owing to the long residence time of water in Lake Gordon, this reservoir mixes inputs of water with varying methylmercury concentrations. Concentrations of total mercury and methylmercury in submerged soils were low and depth profiles of mercury species in the water column did not show evidence of a gradient of mercury concentrations due to releases from the sediments. The concentrations of methylmercury observed in the water column are consistent with the concentrations observed in the fish. A budget of the mercury inputs and outputs to Lake Gordon showed that in-lake processes and sources in the catchment areas both contributed significantly to the concentrations of methylmercury in the lake. The methylation of mercury in Lake Gordon appeared to mainly occur in the surface waters (< 10 m) and was not consistent with processes leading to the methylation of mercury at the oxic/anoxic boundary observed in seepage lakes in Wisconsin. The concentrations of total mercury and methylmercury in bogs in the catchment areas of Lakes Gordon and Pedder, were high and governed by the concentration of organic matter in the sediments. The processes involved in the supply of mercury species from the Lake Gordon and Lake Pedder catchments appear to be similar to those in drainage lakes in the temperate and boreal regions of the northern hemisphere. The formation of the Lake Gordon and Lake Pedder reservoirs appears to have had little impact on the mean annual concentrations of methylmercury released to the downstream environment.

During the independence era in West Africa (1958–1980) many nations embarked on ambitious programmes aimed at rejuvenating their traditional art forms. These programmes were realised through new cultural policies, with music the prime target of the governments’ campaigns. I contend that in the search for an appropriate voice West African governments focussed on one group of musicians, the Mande griots. It was through their musical compositions that the State communicated ideology and doctrine to the public. I assert that to focus on a specific ethnic group and promote them as cultural ambassadors was a policy that conflicted with the core principles of West Africa’s governments, who upheld a doctrine that promoted nationalism over ethnocentrism. It was a neo-colonialist strategy designed to consolidate the rule of the governing party, a contention which I support through an analysis of the role of griots in West African society and an appraisal of the careers of musicians, musical recordings, and musical styles. This thesis represents a historical account of Mande griots in West Africa with respect to their influence on local and national politics. Part of the aim of this thesis is to create a comprehensive and accurate catalogue of West African musical recordings and groups, the results of which are located in the appendices.

<p>Neuropeptide Y (NPY) is known to influence a vast number of physiological and behavioral processes such as vasoconstriction, circadian rhythms, feeding, anxiety and memory. Peptides of the NPY family bind to five different cloned G-protein coupled receptor subtypes (Y1, 2, 4-6). The studies compiled in this thesis present inter-species comparisons of sequence similarities, binding properties and expression patterns among receptors of the NPY family.</p><p>Cloning of Y1 and Y2 receptor subtypes from guinea pigs revealed strong binding profile similarity to the corresponding human receptors. Previously demonstrated atypical binding profiles in the caval vein of guinea pigs were concluded to result from other receptors than the cloned Y1 and Y2 receptors, or possibly combinations of distinct receptor subtypes.</p><p>The guinea pig Y5 receptor was found to be expressed in regions of the brain that have been indicated as important for regulation of food intake. Expression in the hypothalamus, amygdala and brain stem was noticed, similar to studies in rats and humans. In other brain regions, such as the striatum and hippocampus, some species differences were observed.</p><p>Mutagenesis studies of the human Y1 receptor indicated sites important for binding both of endogenous agonists and synthetic antagonists. Putative new sites of interaction with the Y1 antagonists BIBP3226 and/or SR120819A were recognized. The data were used to construct a three-dimensional structure model, based on a high-resolution bovine rhodopsin model.</p><p>Cloning of the chicken (<i>Gallus gallus</i>) Y1, Y2 and Y5 receptors revealed high sequence similarities with mammalian receptors. Most endogenous ligands bound with similar affinities as to mammalian receptors. The strongest exception was the discovery of high-affinity binding to chicken Y2 of [Leu³¹, Pro³⁴]NPY, which was previously considered to bind non-Y2 receptors only. </p><p>The new human Y1 receptor model provides a basis for further investigations of ligand-receptor interactions which will be aided by information on NPY receptors from other taxa. Guinea pigs are concluded to be a good complement to rats and mice for studying NPY signaling. These results demonstrate the benefits of species comparisons for pharmacological studies.</p>

Au cours de ces années de Doctorat, nous avons étudié les effets ototoxiques de certains médicaments et les moyens de prévenir les surdités neuro-sensorielles quils peuvent induire. Parmi ces molécules, nous nous sommes concentrés sur les plus couramment utilisées en pratique clinique : les antibiotiques de la famille des aminoglycosides et le cisplatine, un agent anti-cancéreux. Lintroduction de notre travail replace la surdité dans son contexte de santé publique. En particulier, nous décrivons pourquoi les médicaments ototoxiques sont utilisés et dans quelles circonstances. Nous présentons la structure de loreille interne et nous tentons dexpliquer sa vulnérabilité aux molécules ototoxiques. Nous abordons ensuite les moyens de prévention et/ou de traitement de ces atteintes neuro-sensorielles pharmaco-induites. Outre les moyens classiques de prévention, que sont les facteurs trophiques et les antioxydants, nous décrivons de nouvelles voies dapproche que sont les voies de signalisation impliquant la protéine kinase C ou la cascade dactivation RhoA/ROCK. La présentation de notre travail original sarticule autour de deux parties. Dans la première partie, nous rapportons les résultats obtenus au cours de notre étude de la toxicité des aminoglycosides et du cisplatine chez la souris et le cobaye in vivo. Nous avons mis en évidence une différence de vulnérabilité significative entre ces deux espèces face à lagression ototoxique. Cette différence existe au niveau fonctionnel, mis en évidence par létude des potentiels évoqués auditifs, et au niveau anatomique, étudié en histologie et en immunohistochimie. Nous en discutons les implications en recherche et en pratique clinique. Dans la seconde partie, nous étudions les moyens de prévenir cette surdité in vivo et in vitro. Nous avons utilisé un modèle de surdité par aminoglycoside chez le cobaye. Nous avons testé et validé une technique de perfusion intra-cochléaire in vivo. Nous avons observé les effets de deux molécules expérimentales : la Bryostatine 1, un activateur de la protéine kinase C, et un inhibiteur de la voir RhoA-ROCK. Leffet protecteur de ces molécules est actuellement limité au ganglion spiral, dont la survie est essentielle à tout traitement dimplantation prothétique et de réadaptation. Nous discutons des perspectives en médecine humaine dans notre conclusion. In this work, we focused our attention on the effects of main ototoxic drugs i.e. aminoglycosides and cisplatin in mammals. We identified new avenues for the prevention of this toxicity. In the introduction, we described how and why ototoxic drugs are used. We then described potential otoprotective strategies in neurosensory deafness. Among them, trophic factors and antioxidant molecules have been widely used. New otoprotective approaches do exist, implying the protein kinase C or RhoA/ROCK signalling. Our original work was presented in two parts. In the first part, we reported the in vivo effects of aminoglycosides and cisplatin in two mammalian species: mice and guinea pigs. Contrarily to guinea pigs, evidence of mice resistance to ototoxicity was found at a functional level, assessed by auditory brainstem responses, and at an anatomical level, studied by immunohistochemistry. We discussed the implication of such differences in research and in clinical practice. In the second part, we studied the effect of two potential otoprotective molecules: Bryostatine 1, an activator of the protein kinase C, and Y-27632, a Rho kinase inhibitor. We showed that these molecules are protecting spiral ganglion neurons both in vitro and in vivo. Survival of spiral ganglion neurons is crucial in the management and rehabilitation of deafness. The potential perspectives of these results in human medicine were discussed.

Neuropeptide Y (NPY) is known to influence a vast number of physiological and behavioral processes such as vasoconstriction, circadian rhythms, feeding, anxiety and memory. Peptides of the NPY family bind to five different cloned G-protein coupled receptor subtypes (Y1, 2, 4-6). The studies compiled in this thesis present inter-species comparisons of sequence similarities, binding properties and expression patterns among receptors of the NPY family. Cloning of Y1 and Y2 receptor subtypes from guinea pigs revealed strong binding profile similarity to the corresponding human receptors. Previously demonstrated atypical binding profiles in the caval vein of guinea pigs were concluded to result from other receptors than the cloned Y1 and Y2 receptors, or possibly combinations of distinct receptor subtypes. The guinea pig Y5 receptor was found to be expressed in regions of the brain that have been indicated as important for regulation of food intake. Expression in the hypothalamus, amygdala and brain stem was noticed, similar to studies in rats and humans. In other brain regions, such as the striatum and hippocampus, some species differences were observed. Mutagenesis studies of the human Y1 receptor indicated sites important for binding both of endogenous agonists and synthetic antagonists. Putative new sites of interaction with the Y1 antagonists BIBP3226 and/or SR120819A were recognized. The data were used to construct a three-dimensional structure model, based on a high-resolution bovine rhodopsin model. Cloning of the chicken (Gallus gallus) Y1, Y2 and Y5 receptors revealed high sequence similarities with mammalian receptors. Most endogenous ligands bound with similar affinities as to mammalian receptors. The strongest exception was the discovery of high-affinity binding to chicken Y2 of [Leu31, Pro34]NPY, which was previously considered to bind non-Y2 receptors only. The new human Y1 receptor model provides a basis for further investigations of ligand-receptor interactions which will be aided by information on NPY receptors from other taxa. Guinea pigs are concluded to be a good complement to rats and mice for studying NPY signaling. These results demonstrate the benefits of species comparisons for pharmacological studies.

Myringotomy plays an important role in otological therapy. The procedure requires an efficient anesthesia, which can be obtained without general anesthesia. However, the use of local anesthetics on the tympanic membrane (TM) has been abandoned in many places, as general anesthesia has been readily available. In the present study the effects of some commonly used topical anesthetics on the TM structure and inner ear were tested in an animal model (rat and guinea pig).Four different anesthetic compounds—Xylocaine®, Bonain's liquid, phenol and Emla®—were applied to the TMs of the animals, which were sacrificed 10 minutes to 5 months after application. Morphological effects regarding time after treatment and number of applications were elucidated. At sacrifice the tissue was fixed and the TMs analysed by light microscopy (LM) and transmission electron microscopy (TEM). In nine animals phenol, Xylocaine® Spray or Emla® was applied to the round window niche and ABR recordings were made at 24 h to 6 months after exposure. After the final ABR evaluation the animals were sacrificed and the cochleae prepared for LM and scanning electron microscopy (SEM).On the TM phenol and Bonain's liquid caused instant destruction of the keratinizing stratified squamous epithelium followed by long-lasting hyperplasia of this epithelium and the underlying connective tissue. A pronounced hyperplasia of these two layers was also noted for the Xylocaine® Spray group, but without immediate destruction of the keratinizing epithelium. The extent of structural changes differed in relation to the extent of spreading of the agent. Emla® showed little, if any, sign of epithelial reaction and had no effect on the connective tissue. Regarding the inner ear Emla®, Xylocaine® Spray and phenol induced significantly impaired ABR thresholds mainly affecting the higher frequencies. However, the impaired ABR thresholds were reversible and at the end of the experiment there was no significant impairment compared to the control data. All agents, except Xylocaine®, damaged the hair cells in the basal part of the cochlea as shown by cytocochleogram and SEM analysis.Instant destruction of the epidermis seems to be necessary for an instant anesthetic effect. All agents caused profound connective tissue reactions. The manner of application, depending on the physical properties of the agent, determined the extent of the structural changes. The changes of the connective tissue were concentrated to the submucosal layer, which seems to be the area for reconstruction of the damaged TM. All agents caused functional inner ear changes. With the exception of Xylocaine® they also caused morphological alterations of the cochlea. The functional changes were partly reversible. Topical anesthetics applied to the TM should be used with caution and when used in an appropriate manner they can be considered safe, especially in an inflamed middle ear, with a thickened round window membrane, which should prevent the agents from reaching the inner ear structures. / digitalisering@umu

University of Macau / Faculty of Law

The objective of this thesis is to study two Basins of the Gulf of Guinea (GoG), namely the Dahomey and the Liberian Basins. These Basins are located in the northern part of the GoG, where oil and gas exploration has significantly increased in the last 10 years or so. We proposed geological descriptions of these two Basins. The key characteristics of the two models are the presence of channels and pinch-outs for depths of between 1 km and 2 km (these values are rescaled for our numerical purposes to 600- m and 700-m depths) and normal faults below 3 km (for our numerical purposes we use 1 km instead of 3 km). We showed that these models are consistent with the plate tectonics of the region, and the types of rocks and ages of rocks in these areas. Furthermore, we numerically generated seismic data for these two models and depth-migrated them. We then interpreted the migrated images under the assumption that the geologies are unknown. The conclusions of our interpretations are that we can see clearly the fault systems in both models. However, our results suggest that seismic interpretations of the channels and pinch-outs associated with the geology of the Dahomey and Liberian Basins will generally be difficult to identify. In these particular cases, we missed a number of channels and pinch-outs in our interpretations. The limited resolution of seismic images is the key reason for this misinterpretation.

La présente thèse étudie la relation entre le niveau de vie, la fécondité des femmes en union et leurs besoins non satisfaits en matière de planification familiale. Les données qui ont servi aux analyses proviennent des fichiers individuels de deux enquêtes démographiques et de santé (DHS) réalisées en Guinée en 1999 et 2005. Le niveau de vie est mesuré par un indicateur composite créé à partir des caractéristiques du logement et certains biens possédés par le ménage. Nous avons adopté deux stratégies d’analyse : analyses descriptives et multi-variées. Nous avons examiné à cet effet les niveaux et les tendances de ces deux comportements de fécondité dans les grandes villes, petites villes et villes secondaires, en milieu rural et à l’échelle nationale. Des méthodes statistiques appropriées ont été utilisées : (modèle de régression de Poisson et des modèles de régression logistique binaire et multinomiale). Les résultats des analyses descriptives montrent une faible fécondité chez les femmes issues des classes riches par rapport aux femmes pauvres et une diminution de leurs besoins non satisfaits en matière de planification familiale. Ces relations qui se sont révélées très statistiquement significatives en 1995-1999 quelque soient les milieux de résidence, ont disparu presque dans les analyses multi-variées, après avoir contrôlé certaines caractéristiques socio-économiques, démographiques et culturelles. Dans ces analyses multi-variées, l’éducation de la femme et la pratique contraceptive se sont révélées particulièrement déterminantes pour la fécondité. Par ailleurs, l’éducation de la femme, a été également un facteur important pour les besoins non satisfaits en matière de planification familiale. Il en est de même pour son âge, sa parité, sa religion, la discussion du couple sur la planification familiale, l’attitude du conjoint vis-à-vis de la planification familiale et de l’exposition aux messages sur la planification familiale qui restent aussi d’importants facteurs des besoins non satisfaits en matière de planification familiale. Le terme d’interaction groupe d’âge et le nombre d’enfants en vie, s’est avéré, lui aussi fortement significatif indiquant que l’effet de la parité sur les besoins non satisfaits en matière de planification familiale ne prend pas le même sens selon le groupe d’âge auquel appartient la femme. En définitive, nos analyses, nos analyses ont mis en évidence que la relation négative entre le niveau de vie, la fécondité et les besoins non satisfaits se vérifie mais avec des degrés variés selon les milieux de résidence et les périodes d’enquête. Les écarts entre les groupes contigus sont également très faibles. / The goal of this thesis is to study the relationship between the married women standard of living, their fertility and their unmet need for family planning. The data used for the analysis have been taken from two individual demographic survey files (DHS) carried out in Guinea in 1999 and 2005. The standard of living is measured using a composite indicator established from the housing characteristics and some capital goods of the family. We have adopted two strategies of analysis: Descriptive and Multivariate Analysis. Thus, we have studied the levels and tendencies of these two behaviors of fertility in the large cities, small or secondary cities, rural places, and at the national scale. Statistics appropriate methods of regression (Poisson regression method, logistic binary method and multinomial method). The results of descriptive analysis have confirmed a weak fertility in women from rich classes in comparison with poor women and a reduction of their unmet need for family planning. The relationship which proved very statistically significant in 1995-1999 whichever the place of residence was not observed with the multivariate analysis method, after controlling some socioeconomic, demographic and cultural characteristics. In the multivariate analysis, the woman education and her behavior in terms of contraception were particularly important in her fecundity. Moreover, the woman’s education, her age, parity (married status), her religion, the discussion of the couple about the family planning, the husband attitude concerning the family planning constitute some important factors of unmet need for family planning. The term of Interaction age group and number of living children turns out strongly significant, indicating that the parity (man-woman) effect can change according to the age group of the woman.   In fact, our analysis have shown with clearly that the negative relationship between the standard of living, the fertility and the unmet need is confirmed with various degrees according to the place of residence and the survey period. The differences between the closely related groups are too weak. / Tous mes travaux ont été réalisés à l'aide du logiciel stata 11.

This thesis seeks to describe the indigenous realities, meanings, and perspectives that are central to the music and dance practices of the Lak (Siar) people in Southern New Ireland, Papua Now Guinea. The insights recorded here are those gained through the experience of twenty-three months living in Rei and Siar villages as a participant in many aspects of Lak social life. The music and dance practices of the region are examined in the context of the wider social and cultural setting. Lak performance realities, are indivisible from kinship structures, ritual proceedings and spirituality. By contextualising Lak music and dance within the frame of the extensive and socially defining mortuary, rites my intention is to show how music and dance not only reflect but also create Lak realities. By examining the ethnographic materials relating to music, dance and performance in the context of mortuary sequence broader elements of Lak society are brought into focus. In these pages I argue that Lak society is reproduced literally and symbolically in these performances.