Le but général de ce travail fut de quantifier la silice biogène (BSiO2) dans les sédiments du continuum de l'Escaut (estuaire – zone côtière), ainsi que son taux de recyclage - rétention. Le coefficient de diffusion moléculaire de la DSi a été déterminé pour différentes valeurs de température et deux salinités et une relation empirique reliant le coefficient de diffusion à la température et à la viscosité de la solution a été établie. La distribution longitudinale de la BSiO2 dans les sédiments de surface, ainsi que les profils verticaux de BSiO2 et de silice dissoute ont été déterminés durant différentes saisons en 2004 et 2005. Les flux de DSi ont été également estimés via des expériences d’incubations et par modélisation des profiles verticaux de DSi. Des expériences de dissolution des sédiments ont permis de déterminer (via modélisation) les constantes cinétiques de vitesse de la BSiO2 et une première évaluation du taux de recyclage de la BSiO2 (5 – 70%). Sur base des calculs à partir des profiles de DSi dans l’eau interstitielle, le taux de recyclage de la BSiO2 varie entre 8 et 92% dans l’estuaire, ce qui correspond à une rétention moyenne de la BSiO2 supérieure à 60%, et souligne ainsi l'efficacité du filtre estuarien par rapport à la silice. En revanche, le recyclage de BSiO2 dans la zone côtière apparaît comme très intensif, avec des valeurs souvent supérieures à 40%. Ces résultats montrent l'importance d'inclure les estuaires dans le calcul des budgets globaux de Si. / The general objective of this study was to quantify the BSiO2 in the sediments of the Scheldt continuum, together with its recycling and retention in this area. First an empirical relation linking the diffusion coefficient of DSi to temperature and salinity was determined, via diffusion experiments. The longitudinal BSiO2 distribution in surface sediments and the vertical BSiO2 and DSi profiles in sediment cores where then measured during 2 years and different seasons, together with other parameters characterizing pore waters, such as alkalinity, pH, sulphate… DSi fluxes were also estimated either directly through whole core incubations measurements or via modelling of interstitial water profiles. BSiO2 dissolution experiments allowed the evaluation of the kinetic rate constants also through modelling of the results, and gave preliminary information over the BSiO2 recycling rates (5 – 70%). The recycling rate as obtained from pore water profiles vary between 8 and 92%, with an average value of about 32%, which highlights the importance of the estuarine filter for silica. Recycling is much more intense in the coastal area, with values up to 40%, which we explain by higher salinity and higher sediment permeability. The different experiments and results also indicated that secondary mineral precipitation might be and important process affecting BSiO2 in the Scheldt sediments.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Ghana is considered an oasis of peace despite having the same mix of ethno-political competitions for state power and resources; north-south horizontal inequalities; ethno-regional concentrations of Christians and Muslims; highly ethnicised elections; a natural resource dependent economy; and a politically polarized public sphere, among others, that have plunged other countries in Africa into violent and often protracted national conflicts. Use of the conflict paradigm to explain Africa's conflicts glosses over positive deviance cases such as Ghana. This study used the peace paradigm in a mixed method, grounded theory research to examine Ghana's apparent exceptionalism in staving off violent national conflicts. From the survey of 1429 respondents and 31 Key Informants, findings indicate Ghanaians are divided on whether their country is peaceful or not. They are equally divided on classifying the state of peace in Ghana as negative or positive. Instead, they have identified sets of centrifugal and centripetal forces that somehow self-neutralize to keep Ghana in a steady state of unstable peace. Among the lift forces are strongly shared cultural and Indigenous African Religious values; symbiotic interethnic economic relationships; identity dissolution and cultural miscegenation due to open interethnic systems of accommodation and incorporation; and the persistence of historical multi-lateral political, sociocultural, and economic relationships. On the drag side are the youth bulge; emergent religious intolerance; elite exit from the state in using private solutions for public problems; and highly politicized and partisan national discourses that leave the country with no national agenda. In sum, Ghana is no exception to the rule. The four interconnected meso theories that this study identifies provide pointers to what factors Ghana needs to strengthen to avert descent into violence.

Indiana University-Purdue University Indianapolis (IUPUI) / In 2008, grassroots NGOs formed 13 alliances in response to the need for emergency relief and post-disaster recovery after the Sichuan Earthquake that occurred in West China and killed approximately 87,000 people. These alliances served to raise and deliver relief materials, train and supervise volunteers, promote information sharing, and assist victims with mental health and livelihood recovery. However, all alliances were terminated within less than four years. Although plenty of scholarship discusses how corporate alliances evolve or fail, few studies focus on interorganizational collaboration among nonprofits. To explore how NGOs developed collective actions in China’s adverse sociopolitical environment, the author performed three years of observation in four coalitions and interviewed 60 alliance leaders, employees, and volunteers. This paper identifies four types of termination these NGO alliances experienced: three of them failed at their very births, five self-disbanded shortly after the end of emergency aid, three dissolved due to failed institutionalization, and the remaining two evolved into independent organizations. Tracking their life cycles, this study finds four main factors accountable for their terminations: political pressure, funding shortage, short-term orientation, and leadership failure. In particular, the repressive NGO regulation regime and limited funding sources fundamentally restricted all alliances’ capacity and sustainability. Further, the transient nature of disaster relief efforts and the conflict between disaster management and planned work areas contributed to the short-term orientation among alliance members and, thus, led to the closure of some alliances shortly after they provided emergency relief. In addition, though generally exempt from internal rivalry that often undermines inter-firm partnerships, NGO alliances of all types were confronted with leadership challenges—partner misfits concerning resources, strategy, and mission; flawed governing structures, and undesired individual leadership. The four factors interplayed and led to alliance dissolution through different combinations. The paper points out that, in addition to environmental uncertainty, leadership failure has become a major challenge for nonprofit collaborations.

Substantive gender equality has yet to be achieved in South Africa. As such, when a decision is made for one of the spouses to a civil marriage to stay at home and care for the children born of the marriage, or make career sacrifices to care for children, that spouse is usually the wife. As a result, while the husband continues to amass wealth and grow his earning potential, the wife is unable to do so. In circumstances where such spouses are married out of community of property or subject to the accrual system with onerous exclusion clauses in the antenuptial contract, the wife may be left with little more than a claim for rehabilitative maintenance in the event of a divorce. The courts only have the discretion to make an equitable distribution of marital property in civil marriages with complete separation of property concluded prior to 1 November 1984 (or 2 December 1988) and customary marriages. It is arguable that this limitation of the judicial discretion violates the equality clause contained in the Constitution of the Republic of South Africa, 1996. A broad judicial discretion to equitably redistribute the spouses’ assets upon divorce is therefore proposed in this dissertation. / Private Law / LL.M.

Substantive gender equality has yet to be achieved in South Africa. As such, when a decision is made for one of the spouses to a civil marriage to stay at home and care for the children born of the marriage, or make career sacrifices to care for children, that spouse is usually the wife. As a result, while the husband continues to amass wealth and grow his earning potential, the wife is unable to do so. In circumstances where such spouses are married out of community of property or subject to the accrual system with onerous exclusion clauses in the antenuptial contract, the wife may be left with little more than a claim for rehabilitative maintenance in the event of a divorce. The courts only have the discretion to make an equitable distribution of marital property in civil marriages with complete separation of property concluded prior to 1 November 1984 (or 2 December 1988) and customary marriages. It is arguable that this limitation of the judicial discretion violates the equality clause contained in the Constitution of the Republic of South Africa, 1996. A broad judicial discretion to equitably redistribute the spouses’ assets upon divorce is therefore proposed in this dissertation. / Private Law / LL. M.

Research on entrepreneurship focuses on success which ignores the high failure rate of new ventures. Many new ventures fail so how entrepreneurs deal with it when their venture fails? Successful entrepreneurs praising the advantages of failure as a valuable teacher. The result of failure is regularly filled with economic, social, psychological, and physical health disorder. The aim of this research is to assessment venture failure experiences for entrepreneurs, from the instant result through to recovery for coping with entrepreneurial failure and exit for impact of the closed venture. In this research, aspects of life affected by entrepreneurial failure examine economically, socially and psychologically in highlighting factors that may influence the amount of costs of failure. Next, the research describes how entrepreneurs learn from failure. It presents on the outcomes of venture failure, including coping with failure and recovery together with cognitive and behavioral outcomes. The main objective of the research study is to understand the failure from entrepreneurs who have experienced it and also to make a theoretical framework of failure based on entrepreneurial venture failure experiences. Every entrepreneur starts up a venture with high expectations of achieving success. Failure can be emotionally disturbing, devastating, painful, distressing and costly for the entrepreneur who may have to aspect the stigma of failure and the loss of reputation. The entrepreneur can get involved in grief, heartache, anxiety, depression, shame, rejection and discouragement (Politis &amp; Gabrielsson, 2009). The purpose of the research is to investigate how entrepreneurs realize and react to venture failure. Moreover, entrepreneurs are looking for positive aspects of failure as enhancing experiences that help their coping with entrepreneurial failure, learning from failure, the willingness to begin a new venture and also trigger changes in upcoming decision-making. The purpose of the research is to take a view of the existed experience of failure, taking into consideration impact from the entrepreneurship. / Forskning om entreprenörskap fokuserar på framgång som ignorerar den höga felfrekvensen av nya företag. Många nya företag misslyckas så hur entreprenörer hantera det när deras företag misslyckas? Framgångsrika entreprenörer prisar fördelarna med misslyckande som en värdefull lärare. Resultatet av misslyckande regelbundet fylld med ekonomiska, sociala, psykologiska och fysiska hälsoproblem. Syftet med denna forskning är att bedöma företagets misslyckande upplevelser för företagare, från det ögonblick resultatet genom att återhämtningen för att hantera företagande fel och avsluta för påverkan av den slutna företag. I denna forskning aspekter av livet som påverkas av entreprenörs fel undersöka ekonomiskt, socialt och psykologiskt att belysa faktorer som kan påverka mängden av kostnaderna för ett misslyckande. Därefter beskriver forskningen hur entreprenörer lära av misslyckanden. Den presenterar på resultaten av företagets misslyckande, inklusive hantera fel och återhämtning tillsammans med kognitiva och beteendemässiga utfall.

El análisis de estructuras paleokársticas ha atraído, en los últimos años, el interés de numerosos investigadores a la información que aportan a la geología aplicada y la paleogeomorfología. Estudios recientes se han centrado en la aplicación de técnicas de exploración del subsuelo debido a la escasez de afloramientos. En la presente Memoria se analizan íntegramente las formas de hundimiento pretéritas que afloran discontinuamente con gran detalle, en los acantilados de las costas meridional (plataforma de Llucmajor) y oriental (plataforma de Santanyí) de Mallorca, a lo largo de más de 75 km de línea de costa, afectando a las rocas carbonáticas del Mioceno superior. El estudio se ha centrado en la distribución geográfica, evolución geológica y las características geomorfológicas de estos paleocolapsos, con especial énfasis en su génesis, su relación con la arquitectura y distribución de las facies, así como en las formas y productos asociados.Los paleocolapsos han sido descritos en su contexto litoestratigráfico y estructural dentro de las mencionadas plataformas carbonáticas, siendo este trabajo una contribución al conocimiento del karst en estas unidades geológicas y su relación con las fluctuaciones marinas. La karstogénesis queda reflejada en estas formas pretéritas donde se han observado depósitos y formas de disolución ligadas a la dinámica kárstica controlada, en el caso que nos ocupa, por las fluctuaciones del nivel del mar: brechas, sedimentos detríticos, cementos, así como distintos tipos y volúmenes de porosidad. La mayor parte de estas formas (sobre un total de 177), cuyas dimensiones en sección varían desde pocos metros hasta afloramientos con 28 m de altura y más de 100 m en la horizontal, se ubican en la plataforma de Santanyí a excepción de dos estructuras ubicadas en la plataforma de Llucmajor.El análisis geológico y su relación con los paleocolapsos muestra como en la plataforma de Llucmajor éstos afectan a las facies de la Unidad Complejo Arrecifal (facies de back reef y frente arrecifal). Sin embargo, en la plataforma de Santanyí, los paleocolapsos afectan tanto a parte del Complejo Arrecifal (facies de back reef), como a la totalidad de la Unidad Calizas de Santanyí. A partir del estudio de la arquitectura de facies del Complejo Arrecifal en la plataforma de Llucmajor se ha establecido el modelo deposicional en la plataforma de Santanyí. Sin embargo, ésta última se encuentra compartimentada como consecuencia del control de dos fallas en dirección de orientación E-O en S'Algar y Na Magrana, donde se localiza el contacto entre facies de lagoon externo y talud arrecifal. No obstante, la cartografía y análisis de los lineamientos en dicha plataforma ha permitido identificar dos familias principales con dos direcciones dominantes; NE-SO y NO-SE, siendo la dirección E-O menos representativa. Se han observado fracturas distensivas y pequeñas fallas inversas miocenas asociadas al proceso de colapso, así como fracturas y fallas postmiocenas, y fracturas cuaternarias.El estudio de la geometría en sección de los paleocolapsos pone de relieve que la formas en "V", "U" y conoidales son las más comunes. Han sido identificadas dos partes diferentes en un paleocolapso tipo: una inferior donde se observa la paleocavidad ubicada en la base del paleocolapso (lagoon externo y/o frente arrecifal), con una geometría irregular de dimensiones entre 1 m y 9 m rellena por sedimentos adyacentes y suprayacentes a ésta; y una parte superior, coincidente con los bordes de la estructura (lagoon interno/Calizas de Santanyí) buzando con inflexión conoidal hacia la paleocavidad.Se han identificado cuatro tipos de brechas (crackle, crackle-laminae-split, de mosaico y caótica) en las estructuras de paleocolapso asociadas cada una de ellas a distintos niveles estratigráficos y, en algunos paleocolapsos, con una gradación vertical y lateral. Son característicos de estos depósitos los sedimentos detríticos (matriz) y los cementos asociados (vadosos y freáticos). En general, el cemento domina sobre la matriz en la zona inferior del paleocolapso, mientras que por encima, es la matriz la que domina sobre el cemento. El análisis por difracción de Rayos X de la matriz indica para la muestra total que la calcita es el mineral principal y el cuarzo el mineral secundario. En la fracción arcilla, la moscovita, la illita y la caolinita son los minerales más comunes. De ello, junto con el estudio de láminas delgadas en estos depósitos, donde se han observado tamaños de grano en el cuarzo superior a 2 mm, se deduce un ambiente de sedimentación subsuperfical y otro subaéreo de lo que se extrae un origen, proceso de transporte y sedimentación diversos, así como la evolución cristaloquímica en determinados minerales. Los cementos son de naturaleza calcítica, con contenidos relativamente altos en magnesio para los freáticos y bajos para los vadosos. Para el estudio de la porosidad en los paleocolapsos se ha procedido a su clasificación en dos tipos principales, interclasto e intraclasto, a partir de las cuales se ha estudiado la macro y microporosidad. La brecha caótica de colapso es la que presenta volúmenes de porosidad más elevados y tipologías diversas. El análisis de isótopos estables muestra una gran homogeneidad entre la composición isotópica de los cementos, con valores en &#948;18O y &#948;13C ligeros, lo que indica condiciones análogas de precipitación, con dominio de aguas dulces sobre las saladas. Tanto la marca del oxígeno como del carbono parecen indicar que los cementos se depositaron en un período interglaciar coincidente con algún estadio isotópico impar.El estudio de la arquitectura de facies de la plataforma de Llucmajor ha permitido elaborar un modelo genético de ocurrencia para los paleocolapsos y su ubicación espacio-temporal. Dicho modelo, ha sido corroborado por la relación entre la distribución de facies y paleocolapsos en la plataforma de Santanyí, por la observación en algunos paleocolapsos de sedimentos a techo de la Unidad Calizas de Santanyí que sellan la estructura, así como por el tipo de brechas características de colapsos sinsedimentarios (brecha crackle-laminae-split), que muestran una deformación dúctil de los materiales cuando éstos no estaban completamente consolidados, dando lugar a formas laxas de bajo ángulo. Los procesos genéticos que dieron lugar a los paleocolapsos kársticos están directamente relacionados con la alta frecuencia de fluctuación del nivel del mar durante el Mioceno superior, la misma que controló la arquitectura de facies y la posición del nivel freático. Las oscilaciones del nivel freático causaron la alternancia de dominios freáticos y vadosos así como, de agua dulce y agua salada en la interfase, provocando la disolución de los parches coralinos y el posterior hundimiento del techo de las cavidades. El estudio integral de todos estos aspectos junto con el análisis de una red de paleocauces y una playa fósil, ha permitido realizar una reconstrucción paleogeográfica desde el Messiniense en la plataforma de Santanyí e identificar estructuras de paleocolapso postmiocenas y cuaternarias. Con estos datos se ha procedido a la comparación de los paleocolapsos kársticos con otras estructuras similares en el País Vasco y Las Islas de Malta, de lo que se extraen analogías y diferencias, determinadas fundamentalmente por el orden de fluctuación del nivel del mar. Por último, se discute el papel de los paleocolapsos kársticos como elementos que contribuyen en cierta medida a la ocurrencia de hidrocarburos en plataformas carbonáticas, pudiendo ser excelentes reservorios debido al gran número de afloramientos, el volumen de roca afectada y a su elevada porosidad y permeabilidad. / Paleokarst tend to differ from studies of recent and modern karst landforms though is important the genetic understanding of the karst processes for analysis a paleokarst structure. Paleokarst systems form an important class of carbonate record and they have a pronounced lateral and vertical spatial complexity that results from a complex history of formation. Most of the known karst systems are epigenetic and they are the result of near-surface karst processes during periods of subaerial exposure and latter burial compaction and diagénesis. Scale, porosity types and spatial complexities of these paleokarst systems depends on the carbonate rock solubility, paleoclimatic conditions, lowering of base level either by tectonic uplift or sea-level fall and time of subaerial exposure. Uplift, in addition, commonly induces fracturing and faulting that further control karst development. Ascertaining and predicting paleokarstic heterogeneities within carbonate rocks are strategic to fluids field development and optimum production. With current subsurface methods, however, most of the smaller-scale stratigraphic architecture and diagenetic facies are difficult to define. Predictive models for exploration and development are best made from outcrop studies of well-exposed examples. Accuracy for prediction of these models depends on the detailed understanding of the genetic factors controlling their geometries, scale, pore networks and spatial complexities of these potential karstic store. Miocene carbonates (Upper Tortonian-Lower Messinian) in Mallorca Island are composed of reefal (Reef Complex) and shallow water carbonates (Santanyí Limestone) that prograded across platforms surrounding paleoislands. The contact between the Reef Complex and the Santanyí Limestone is a subaerial erosion surface with paleokarst features. The shallow-water carbonates beds both the lagoonal beds of the Reef Complex and basal beds of the Santanyí Limestone, are affected by paleocollapse structures produced by roof collapse of caverns developed in the underlying Reefal Complex. These paleocollapse structures affecting to the carbonate platform allows to propose a genetic model to explain the origin of these paleosink, that are related to early diagenetic processes induced by high-frequency sea-level fluctuations, the same sea-level fluctuations that controlled the facies architecture of the carbonate platforms.Cartography and study of lineaments and fractures on Santanyí Platform have permitted identified two principals groups with two main directions: NE-SO and NO-SE. Have been observed distensiva fractures and Miocene small inverse faults related with de breackdwon phenomena. Moreover, postmiocenes and quaternary faults and fractures have been recognized.The geometry of paleocollapse structures is commonly (in section) as "V", "U" or funnel. The size is variable from few meters of long to thousands meters, and few meters of weigh to thirteen meters. Breccias has been classified as crackle, crackle-laminae-split, mosaic and chaotic types. Chaotic breccias grade from matrix-free, clasts-supported breccias to matrix-supported breccias. The matrix mineralogy is compose in the total sample for calcite in the major part and quartz in less quantity. However, same structures present quartz as principal mineral. To the clay fraction, caolinite, illite and moscovite are the most general mineral present.The geochimical sediment (carbonate) are filling a part of interclaste breccias porosity. This is commonly phreatic speleothems. Isotopic studies of this sediments show &#948;18O and &#948;13C contents negatives. This fact could indicate a fresh water environment deposition