The public concern which has materialized in recent years regarding the quality of the nation's surface waters has created a need to upgrade wastewater treatment processes. New treatment objectives, in general, relate to the removal of phosphorus, achieving nitrification, and essentially eliminating the carbonaceous oxygen demand of wastewaters prior to discharge. The objective of this study was to operate a pilot plant scale activated sludge type treatment plant, using domestic sewage and employing alum as a coagulant in the primary process. Alum addition and flocculation were provided prior to a conventional primary clarification process. The secondary treatment consisted of a combination of the complete-mixed and plug-flow process operated in series. It was found that this treatment scheme was capable of removing 95 percent of the total phosphate content of the municipal wastewater in contrast to the 20 to 30 percent removal normally provided by conventional activated sludge plants. The more efficient primary process gave an average reduction in phosphorus of 67 percent. The reduced carbonaceous and nutrient load to the secondary biological process provided more complete phosphate removal and resulted in a reduction in hard-to-handle secondary sludge. In addition to consistently high removals of phosphorus, the pilot plant achieved 93 percent nitrification and reduced influent BOD by 87 percent, on the average. Chemical precipitation was found to be a stable and predictable means of upgrading the effluent of conventional secondary wastewater treatment plants. With a minimum of equipment and capital outlay, the chemical precipitation scheme could be adapted to existing plants or incorporated into the design of new plants. / Master of Science

Cassava (Manihot esculenta Crantz) is an important tropical crop which provides a large portion of daily calories intake to hundreds of millions of people in Africa, Latin America, and tropical Asia. Cassava is grown for its starchy storage roots as staple food, as animal feed, and as industrial raw material. The utilisation of cassava is hindered by its characteristic physiological response, the post-harvest physiological deterioration (PPD). The inevitable wounding caused during harvesting and handling will trigger a series of physiological responses within 24 to 48 hours, which causes a blue-black discoloration in the storage roots, rendering these roots unmarketable and unpalatable in a few days. During the PPD response large amount of phenylpropanoid compounds, especially scopoletin and its glycoside, accumulate in the roots. Scopoletin may play an important role in PPD development but little work has been done on the possible relationship. Here we aim to examine the effects of altering scopoletin synthesis in cassava roots on the PPD response. In Arabidopsis thaliana, gene F6’H1 (feruloul CoA 6’-hydroxylase 1) is indispensable in the biosynthesis of scopoletin. Cassava F6’H1 candidate gene family involved in scopoletin synthesis were identified by their ability to functionally complement F6’H1 T-DNA insertion mutation in Arabidopsis thaliana that prevented synthesis of scopoletin. RNAi constructs targeting the identified cassava F6’H1 candidate gene family were designed, under the control of either constitutive CaMV 35S or root-specific StPAT promoters. These were used to transform wild-type cassava to down-regulate the expression of these scopoletin synthetic genes in F6’H1 gene family. The inhibition of cassava F6’H1 candidate gene expression and thus the scopoletin synthesis in transgenic cassava roots were confirmed by qRT-PCR and LC-MS, respectively. The RNAi transgenic cassava lines show less scopoletin accumulation and inhibited F6’H1 candidate genes expression during the PPD response. A reduced PPD discoloration development compared to that of the wild-type was also observed in the RNAi transgenic cassava lines.

Solar magnetic fields, as well as temperature changes, introduce pressure deviations that play a significant role in modulating the resonant frequencies of p-mode oscillations. Those pressure deviations occurring in the atmosphere or sub-surface of the Sun can explain the frequency shifts observed on the timescale of the solar activity cycle. A separate study of the contribution of internal magnetic layers can clarify the relative importance of surface effects. Results from helioseismology provide realistic constraints for choosing parameters suitable to represent the magnetic layers buried in the solar interior and available for modelling, i.e. at the base of the convection zone and in the sunspots' anchoring zone. Diagnostics of the internal magnetic layers are obtained through a schematic model in which the Sun is plane-stratified. The influence of a buried magnetic field on p-modes is explored, and the nature of various waves and instabilities that can arise on such a buried magnetic field is assessed. By treating the effects of internal magnetic layers, this thesis contributes to the building of a bridge between theories and observations. On the one hand, the theoretical analysis is explored carefully in the course of its formulation, which generates new hypotheses that were not obvious so far. On the other hand, observations help to understand which explanations of the solar cycle frequency shifts may apply.

Includes index / Bibliography: p. 77-79 / i, 145 p. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

No description available.

Aunque tradicionalmente las dificultades asociadas a su estudio han subestimado la importancia de los virus en los ecosistemas, hoy en día el desarrollo de nuevas metodologías nos ha hecho comprender que estos juegan un papel relevante a nivel global, sobre todo en los océanos. La secuenciación del genoma vírico de una muestra ambiental (la virómica) y su posterior reconstrucción (ensamblaje de genomas), ha permitido ampliar el número de virus marinos conocidos, sin embargo, también han puesto de manifiesto la enorme diversidad de genomas víricos que continúan sin ser reconstruidos. En esta tesis, la novedosa metodología de Single-virus genomics (SVGs), una técnica en la que se separan virus mediante sorting y se amplifica y secuencia su genoma de forma individual, fue aplicada con éxito sobre muestras marinas, desvelándose el genoma de virus marinos, previamente desconocidos, a pesar de ser altamente abundantes a lo largo de todos los océanos del planeta. El motivo por el que la virómica no ha podido reconstruir estos genomas fue analizado también en la tesis y se le atribuyó a la (micro-)diversidad de estas abundantes poblaciones víricas. Uno de estos virus obtenidos por SVG, el vSAG 37-F6, resultó ser el más abundante en los océanos. Diferentes métodos in silico, basados en análisis de k-mer, espaciadores CRISPR y búsqueda de ARNt, fueron empleados para tratar de identificar su huésped, sin embargo, no dieron resultado, por lo que se diseñó una aproximación experimental. Se diseñaron unos primers de PCR, específicos para el vSAG 37-F6 y se probaron en una colección de células sorteadas individualmente cuyo genoma había sido amplificado (SAGs). Tras comprobar la correcta amplificación (no inespecificidades) en uno de estos SAGs, se secuenció su genoma, mostrando que estaba relacionado con los Pelagibacteriales, por lo que el vSAG 37-F6 se identificó como un pelagifago. Corroborando este resultado 3 contigs diferentes, similares al vSAG 37-F6 fueron encontrados en otros 3 SAGs identificados también como Pelagibacter sp, obtenidos cada uno de ellos en diferentes localizaciones (Océanos Atlántico y Pacífico), y en tres experimentos y trabajos diferentes. Estos Pelagifagos similares al 37-F6 estaban poco relacionados con los obtenidos por técnicas dependientes de cultivo. La abundancia de los virus en muestras ambientales es tradicionalmente estimada de forma relativa mediante el reclutamiento de fragmentos virómicos. Sin embargo, la ausencia de marcadores específicos dificulta el empleo de métodos para calcular su abundancia de forma absoluta, como se hace con los procariotas. En el tercer capítulo de esta tesis, se muestra la aplicación de la técnica de droplet digital PCR (ddPCR) para calcular la abundancia absoluta de 2 pelagifagos, el vSAG 37-F6, y el HTVC010P. Además, son evaluados los pasos críticos de esta metodología, como es el diseño de primers específicos, o la correlación matemática para su cálculo. Las abundancias absolutas de ambos virus fueron calculadas en tres muestras ambientales diferentes, dos del Mar Mediterráneo, y una del Atlántico Norte, procedente del Golfo de Maine (Estados Unidos). La pareja de primers empleada con el vSAG 37-F6 fue diseñada siguiendo el procedimiento propuesto en este trabajo, mientras que para el HTVC010P se empleó una pareja de primers obtenida de la bibliografía. Los valores de abundancia obtenidos estuvieron comprendidos entre los valores de 1,270-14,400 virus mL-1 y de 360 a 8,510 virus mL-1 para el HTVC010P y el vSAG 37-F6 respectivamente. Sin embargo, la secuenciación de los amplicones obtenidos por PCR, mostró una sobreestimación del 6% para los primers del HTVC010P, pero no para los del vSAG 37-F6. Los dos últimos apartados de esta tesis se corresponden con dos trabajos que están actualmente siendo desarrollados por el doctorando. En el primero de ellos se analiza la (micro-)diversidad de las poblaciones del vSAG 37-F6 desde varios puntos de vista. Y para finalizar la técnica de SVGs es aplicada en muestras marinas de profundidad, de las que poco se conoce actualmente. / La presente tesis ha sido financiada por el Ministerio de Economía y competitividad español (refs. CGL2013-40564-R and SAF2013-49267-EXP), por la Generalitat Valenciana (ref. ACOM/2015/133 and ACIF/2015/332), y por la Gordon and Betty Moore Foundation (ref. 5334).

I sought to find out whether this was a tension between artistic and commercial in the career of visual artists, and if so, how this tension was managed. In attempting to uncover information which could address the research question I undertook in-depth career history interviews with artists which covered their time at art school through to their current practice. The career history method was deliberately chosen in order to address the research question at a tangent as both the literature, and my own personal experience of the field of contemporary visual art, had suggested that the topic of artistic and commercial was a sensitive one. By framing the interviews around the experiences the artists had through the time period of their training and career, I was able to approach the research questions indirectly from the perspective of the artists. Through analysis of the interview transcripts the framework of Bourdieu's capitals arose as one that would capably explain the activities which the artists were undertaken and I used this as a framing device for the empirical chapters in the thesis. In exploring ideas of cultural, social and economic capitals in relation to how artists describe the activities they undertake during their career it became apparent that the broad structures of cultural capital needed further refinement in their application to the careers of visual artists. In the thesis I chose to elaborate further on the concept of artistic capital which has, until now, been unexplored by scholars. I have developed an understanding of artistic capital as a subcategory of cultural capital with particular application to the field of contemporary visual art – with the potential for wider application beyond the thesis. The three capitals of artistic, social and economic proved a capable structure for understanding whether there was a tension between artistic and commercial and how artists managed this. Through this research I have found that artists come to believe, during their early career and training through art school, that there is a tension between artistic and commercial as this is perpetuated by institutions and art world participants through their exclusion or dismissal of commercial aspects of the visual art field. Through their careers they come to realise that this tension is less prevalent than they thought and that they are able to manage these two aspects of artistic and commercial more effectively. However, artists continue to be faced with instances where this tension is imposed upon them by other art world players who perpetuate the belief that there is an inherent, unresolvable tension between artistic and commercial. These individuals attempt to shield artists from this perceived tension later in their careers when artists are already adept at managing the competing priorities of artistic and commercial without the two creating tension.