[No abstract submitted] / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

In order to explore the dynamic between history and place, I consider four methodological issues within the historical space of Sumas Lake, B.C., a large lake that was drained in the 1920’s. The first “Opening” reflects on the connection between historical and technological frontiers, while critiquing my creation of the attached HyperCard stack “Disappearing A Lake: A Meditation on Method and Mosquitos.” The stack documents the creative process of history-making, allowing the “reader” to review and record comments, to see examples of cartography and photography, to hear oral interviews and to read selections of narrative tradition either inside or outside the logic and context of an essay format. The written document flows from the stack. “Listening For Pleasure” discusses the process of oral history as it relates to the negotiated and contested space of the Sumas Lake commons. Diving into archives from Victoria to Ottawa, “Margins and Mosquitos” recycles written records to explore federal, provincial and local involvements with a flood lake. “Memory Device” moves into the archive of land and waterscapes, looking for connections between place and history, mindful of both Native oral tradition and written historical accounts of the lake. Interactive history is located not only in the interface between people and computers, but also in the process of making oral history and in the creative transformation of archival documents. Most importantly, interactive history is alive in the links people forge between stories and the actual places around them.

In order to explore the dynamic between history and place, I consider four methodological issues within the historical space of Sumas Lake, B.C., a large lake that was drained in the 1920’s. The first “Opening” reflects on the connection between historical and technological frontiers, while critiquing my creation of the attached HyperCard stack “Disappearing A Lake: A Meditation on Method and Mosquitos.” The stack documents the creative process of history-making, allowing the “reader” to review and record comments, to see examples of cartography and photography, to hear oral interviews and to read selections of narrative tradition either inside or outside the logic and context of an essay format. The written document flows from the stack. “Listening For Pleasure” discusses the process of oral history as it relates to the negotiated and contested space of the Sumas Lake commons. Diving into archives from Victoria to Ottawa, “Margins and Mosquitos” recycles written records to explore federal, provincial and local involvements with a flood lake. “Memory Device” moves into the archive of land and waterscapes, looking for connections between place and history, mindful of both Native oral tradition and written historical accounts of the lake. Interactive history is located not only in the interface between people and computers, but also in the process of making oral history and in the creative transformation of archival documents. Most importantly, interactive history is alive in the links people forge between stories and the actual places around them. / Arts, Faculty of / History, Department of / Graduate

This thesis concerns groundwater quality with a detailed study of the Abbotsford-Sumas Aquifer and the high nitrate-nitrogen values that have been occurring for the past 20 or so years. Groundwater is becoming an increasingly scarce resource, both in terms of quantity and quality, worldwide. Aquifers are generally poorly understood, dynamic and are an integral part of the hydrological cycle. Aquifer contamination by land use activities threatens their utility as potable sources of water. The literature suggests that one useful measure of the effects of land use on water contamination is nitrate-nitrogen. This substance may be traced to such activities as agricultural practices and septic systems, two major concerns in the area above the Abbotsford-Sumas Aquifer in southwestern British Columbia. The Abbotsford-Sumas Aquifer was examined in detail with a review of the history, geology, hydrogeology, stakeholders, groundwater use and the current identified contamination. Based on the hydrogeology and land use of the aquifer, a representative study area was selected as a case study. With a focus on nitrate-nitrogen the principle objectives were: to determine land use effects on groundwater contamination, assess the contributions of various nitrogen sources and assess the overall impact of intensive land use on the groundwater contamination. This was investigated by a temporal land use evaluation, a nitrogen / nitrate balance and a review of water quality changes. The major land use change in the study area over the period 1969 to 1992 has been the increase in land used for raspberry production which now accounts for over half of the study area. The nitrogen balance revealed a large quantity of nitrogen unaccounted for which is potentially available for leaching. The predominate source of this excess nitrogen is attributed to the high levels of poultry manure fertilizer applied to the soils supporting raspberry crops. Calculations of the nitrogen sources suggest over 90 percent of the excess nitrogen comes from this source. This was well above the other nitrogen sources such as mineralisation, aerial deposition, septic systems, corn crops and pasture land. Although a minor overall nitrogen source, septic tanks appeared to have the potential for high local loadings of nitrate-nitrogen. The water quality data showed increases in nitrate-nitrogen concentrations in the groundwater over the last 40 years. Seventy percent of the water samples showed nitrate-nitrogen values above the Canadian Drinking Water Guideline maximum value allowed in drinking water. The data however displayed significant variability.

This thesis concerns groundwater quality with a detailed study of the Abbotsford-Sumas Aquifer and the high nitrate-nitrogen values that have been occurring for the past 20 or so years. Groundwater is becoming an increasingly scarce resource, both in terms of quantity and quality, worldwide. Aquifers are generally poorly understood, dynamic and are an integral part of the hydrological cycle. Aquifer contamination by land use activities threatens their utility as potable sources of water. The literature suggests that one useful measure of the effects of land use on water contamination is nitrate-nitrogen. This substance may be traced to such activities as agricultural practices and septic systems, two major concerns in the area above the Abbotsford-Sumas Aquifer in southwestern British Columbia. The Abbotsford-Sumas Aquifer was examined in detail with a review of the history, geology, hydrogeology, stakeholders, groundwater use and the current identified contamination. Based on the hydrogeology and land use of the aquifer, a representative study area was selected as a case study. With a focus on nitrate-nitrogen the principle objectives were: to determine land use effects on groundwater contamination, assess the contributions of various nitrogen sources and assess the overall impact of intensive land use on the groundwater contamination. This was investigated by a temporal land use evaluation, a nitrogen / nitrate balance and a review of water quality changes. The major land use change in the study area over the period 1969 to 1992 has been the increase in land used for raspberry production which now accounts for over half of the study area. The nitrogen balance revealed a large quantity of nitrogen unaccounted for which is potentially available for leaching. The predominate source of this excess nitrogen is attributed to the high levels of poultry manure fertilizer applied to the soils supporting raspberry crops. Calculations of the nitrogen sources suggest over 90 percent of the excess nitrogen comes from this source. This was well above the other nitrogen sources such as mineralisation, aerial deposition, septic systems, corn crops and pasture land. Although a minor overall nitrogen source, septic tanks appeared to have the potential for high local loadings of nitrate-nitrogen. The water quality data showed increases in nitrate-nitrogen concentrations in the groundwater over the last 40 years. Seventy percent of the water samples showed nitrate-nitrogen values above the Canadian Drinking Water Guideline maximum value allowed in drinking water. The data however displayed significant variability. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

Esta tesis doctoral, realizada bajo la dirección de Juan Matías Sepulcre Martínez, supone para este doctorando culminar un periodo extenso de investigación iniciada hace ya bastantes años en el seno del antiguo Departamento de Análisis Matemático y continuada en el tiempo en el Departamento de Matemáticas de la Universidad de Alicante. Fruto de este trabajo de investigación conjunta, son varios los artículos ya publicados (en los que el doctorando figura como coautor) que están contextualizados en el tópico de la tesis. Sin embargo, esta memoria incluye también material original reciente, surgido en el periodo de matrícula en el doctorado, que ha dado lugar a varios preprints que se han enviado o se enviarán próximamente para su posible publicación en revistas de reconocido prestigio. La memoria de la tesis se divide en seis capítulos y comienza con una introducción en la que se exponen las principales herramientas de trabajo y la notación básica utilizada a lo largo de todo el texto. Los conceptos de propiedad de Q−estructura, matrices de Q−estructura, sistema y límite inverso o compactificación de Bohr serán los protagonistas principales de esta parte introductoria. Los capítulos 2, 3 y 4 tienen una estructura similar. A partir de la propiedad de Q−estructura (en términos de relación de equivalencia) y la noción de matrices de Q−estructura de vectores o redes compuestas de una respectiva cantidad finita, infinita numerable y continua de números reales, construiremos espacios vectoriales relacionados con las clases de equivalencia generadas por tal relación de equivalencia. A partir de ello se formarán los subgrupos abelianos compactos en el toro que nos conducirán a compactificaciones de Bohr para los distintos casos expuestos en esta memoria (que son únicas en las clases de equivalencia conteniendo los vectores prefijados). Aunque la mayoría de los resultados tratados se extienden desde el caso finito al caso infinito numerable y continuo, las herramientas utilizadas en las demostraciones de cada uno de estos capítulos serán distintas por el hecho de trabajar con cardinales y contextos distintos. En concreto, el objetivo principal del capítulo 2 es la construcción de subconjuntos concretos del toro N-dimensional, con N∈N (dado por el producto cartesiano de N copias del toro 1−dimensional), que están conectados de una forma específica con las clases de equivalencia originadas a partir de la propiedad de Q−estructura para vectores de números reales. De hecho, demostraremos que estos subconjuntos constituyen grupos abelianos compactos que desembocan en compactificaciones de Bohr de ciertas líneas y espacios vectoriales asociados con los vectores prefijados de números reales, e incluso en compactificaciones de Bohr de los espacios euclídeos R^k para un cierto k∈N. Con la ayuda de la noción de sistema y límite inverso, en el capítulo 3 acabaremos construyendo subconjuntos concretos del toro infinito-numerable-dimensional (dado por el producto cartesiano infinito numerable de copias del toro 1−dimensional) que están conectados con las clases de equivalencia originadas a partir de la propiedad de Q−estructura para vectores (con una cantidad infinita numerable de componentes) de números reales. Demostraremos que estos subconjuntos nos ayudan a establecer conexiones y caracterizar la propiedad de Q−estructura. Finalmente, analizaremos la compacidad de tales conjuntos, lo que nos conducirá a establecer compactificaciones de Bohr de ciertas líneas y espacios vectoriales asociados con los vectores prefijados de números reales e incluso son compactificaciones de Bohr de los espacios euclídeos R^k para un cierto k∈N∪{∞}. En el capítulo 4 construiremos subconjuntos concretos del toro infinito-continuo-dimensional (dado por el producto cartesiano de un continuo de copias del toro 1−dimensional) que están conectados con las clases de equivalencia originadas a partir de la propiedad de Q−estructura para redes compuestas de un continuo de números reales. Mostraremos la relación concreta entre tales subconjuntos y caracterizaremos la propiedad de Q−estructura en términos de ellos. Posteriormente extenderemos al caso continuo los resultados sobre las compactificaciones de Bohr de los dos capítulos anteriores, y proporcionaremos una demostración del potente resultado consistente en afirmar que estos subconjuntos constituyen compactificaciones universales de Bohr del conjunto de los números reales, lo que constituye una propiedad más exigente que la de la compactificación de Bohr. En el capítulo 5 expondremos otras relaciones de equivalencias definidas sobre los espacios R^N, T^N y C^N, con N∈N∪{∞}, que nos conducirán a otras compactificaciones de Bohr. Además, mostraremos que estas nuevas compactificaciones de Bohr dan lugar a ciertas teselaciones del toro infinito y de sus conjuntos isomorfos. Probaremos algunas caracterizaciones de estas equivalencias en términos de las llamadas órbitas de puntos en tales espacios. Otras caracterizaciones de estas nuevas equivalencias nos darán pie en el capítulo 6 a establecer vínculos con la teoría de las funciones casi periódicas y las sumas exponenciales. En particular, veremos la diferencia existente entre Bohr-equivalencia (basadas en la definición que manejó Harald Bohr en el contexto de las series generales de Dirichlet) y nuestra propuesta de SV-equivalencia para las funciones incluidas en los espacios de funciones casi periódicas definidas en los números reales o en bandas verticales del plano complejo. Este estudio conlleva un desarrollo importante para la comprensión de los pilares principales de la teoría de las funciones casi periódicas. La inclusión de ejemplos y de etiquetas en la mayoría de las definiciones y resultados es otra característica en la redacción de esta memoria que pretende hacer más amena la lectura.