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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Transportation infrastructure and regional development in northern Manitoba: realities and prospects

Pratte, Stephen 03 April 2012 (has links)
The relationship between transportation and economic development is well documented. Two requirements indispensable to this relationship are access (ability to reach a place) and connectivity (relationship of the place to others). The interaction of people and markets via transportation infrastructure facilitates trade and increased social interaction; all vital for development. This thesis examines the nature of access and connectivity of the multi-modal transport network (i.e. road, rail, water and air modes) of Northern Manitoba, a study area characterized by many small communities distributed in a vast area, with some having no year-round overland access, forcing them to rely on the seasonally constructed winter road system. Models of the four modal networks (graph theory) are used to analyze the transportation network’s structure, accessibility and connectivity for specific points in time with a view to understand network change. Recommendations are offered that would facilitate the integration of transportation planning.
62

Baseline hydrogeochemistry and connectivity among landscape units of two wetland-rich Boreal sites in the Athabasca Oil Sands Region, Alberta

Kusel, Caren 21 May 2014 (has links)
Developing critical loads for nitrogen (N) in the Athabasca Oil Sands Region (AOSR) requires an understanding of the hydrological connectivity and potential for N transport among uplands, fens and bogs typical in the wetland-rich Boreal region of northern Alberta. The Cumulative Environmental Management Association’s (CEMA) overarching mandate is to determine a nitrogen critical load specific to the Boreal region of northern Alberta. To this end, nitrogen amendment experiments were initiated at two Boreal wetland sites: an upland – rich fen gradient at Jack Pine High (JPH) and an upland – fen – bog mosaic at Mariana Lakes (ML), 45 km north and 100 km south of Fort McMurray respectively. The objectives of this study are to use geochemical and isotopic tracers to describe baseline hydrogeochemical variability and connectivity between bog, fens and upland areas in the AOSR. Sites were instrumented with piezometer nests and water table wells along transects that cover the targeted landscape units (n = 108 sampling locations). Fieldwork related to this thesis was conducted during the open-water season: in June and August 2011, and in May, July, and September 2012. Field campaigns also included a snow survey (March 2012), and spring melt/freshet sampling (April 2012). The analysis of spatiotemporal variability of water isotopes and geochemistry in the years 2011-2012 yielded: i) a characterization of baseline conditions from which perturbations can be assessed, and ii) evidence of connectivity among landscape units. No evidence for elevated concentrations of nitrogen related to the amendment experiments was found in 2011 or 2012. The baseline characterization and annual monitoring did show increasing concentrations of inorganic ammonium with increasing depth associated with increasing solute concentrations: average concentrations of inorganic ammonium were 23 mg/L at deepest sampling locations (7 m) at ML bog and ML fen landscape units. These ammonium concentrations in porewaters, given a porosity of 0.90 for peatlands, constitute a store of ammonium that may be a significant source of nitrogen if the hydrology is altered due to co-occurring changes in vegetation (due to, for example, elevated nitrogen inputs), climate and/or landuse. Hydrologic connectivity at JPH is likely driven by topography. Hydraulic head in 2011 and 2012 field seasons showed that flow persisted from the upland to the fen. The consistent and distinct geochemical signatures and isotopic labelling of mid-depth and deep groundwater samples of fen and upland landscape units is consistent with such a stable groundwater continuum. Near-surface water samples at JPH fen however varied hydrogeochemically in response to seasonal changes in precipitation inputs, water levels, and biogeochemical productivity. At ML, hydrological connectivity is a function of antecedent moisture conditions (which determines run-off) and low and variable (10-6 to 10-9 m/s) hydrological conductivity of the peatland substrate (which may result in lateral flow where hydraulic head shows potential for vertical re- or discharge). Near-surface samples showed greater temporal than spatial variability as snowmelt inputs, variations in antecedent moisture conditions and seasonal changes in biogeochemical process rates affected nutrient and solute concentrations. In contrast, shallow, mid-depth and deep samples showed greater spatial than temporal variability. The spatial distributions of parameters could be associated to some degree with vegetation, distance along a surficial flowpath, or depth to mineral substrate or distance from the upland/edge transition. / Graduate / 0996 / 0388 / 0425 / cbkusel@yahoo.ca
63

Experimental models for network mesh topologies with designs that enhance survivability / John Mugambwa Serumaga-Zake

Serumaga-Zake, John Mugambwa January 2006 (has links)
Network design problems involving survivability usually include trade-off of the potential for lost revenues and customer goodwill against the extra costs required to increase the network survivability. It also involves selection of nodes and edges from lists of potential sets to accomplish certain desirable properties. In many applications it is imperative to have built-in reliability or survivability of the network. Delays of traffic are undesirable since it affects quality of service (QoS) to clients of the network. In this dissertation we consider the construction of an optimization system for network design with survivability properties that may help in the planning of mesh topologies while maintaining a certain degree of survivability of the network. This is done by providing for at least two diverse paths between certain "special" nodes to provide protection against any single edge or node failure. This part is modelled by using mixed integer programming techniques. A software product called CPLEX then solves these models and various facilities are built into the decision support system to allow the decision maker to experiment with some topological and flow requirement changes. / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2007
64

Transportation infrastructure and regional development in northern Manitoba: realities and prospects

Pratte, Stephen 03 April 2012 (has links)
The relationship between transportation and economic development is well documented. Two requirements indispensable to this relationship are access (ability to reach a place) and connectivity (relationship of the place to others). The interaction of people and markets via transportation infrastructure facilitates trade and increased social interaction; all vital for development. This thesis examines the nature of access and connectivity of the multi-modal transport network (i.e. road, rail, water and air modes) of Northern Manitoba, a study area characterized by many small communities distributed in a vast area, with some having no year-round overland access, forcing them to rely on the seasonally constructed winter road system. Models of the four modal networks (graph theory) are used to analyze the transportation network’s structure, accessibility and connectivity for specific points in time with a view to understand network change. Recommendations are offered that would facilitate the integration of transportation planning.
65

Baseline hydrogeochemistry and connectivity among landscape units of two wetland-rich Boreal sites in the Athabasca Oil Sands Region, Alberta

Kusel, Caren 21 May 2014 (has links)
Developing critical loads for nitrogen (N) in the Athabasca Oil Sands Region (AOSR) requires an understanding of the hydrological connectivity and potential for N transport among uplands, fens and bogs typical in the wetland-rich Boreal region of northern Alberta. The Cumulative Environmental Management Association’s (CEMA) overarching mandate is to determine a nitrogen critical load specific to the Boreal region of northern Alberta. To this end, nitrogen amendment experiments were initiated at two Boreal wetland sites: an upland – rich fen gradient at Jack Pine High (JPH) and an upland – fen – bog mosaic at Mariana Lakes (ML), 45 km north and 100 km south of Fort McMurray respectively. The objectives of this study are to use geochemical and isotopic tracers to describe baseline hydrogeochemical variability and connectivity between bog, fens and upland areas in the AOSR. Sites were instrumented with piezometer nests and water table wells along transects that cover the targeted landscape units (n = 108 sampling locations). Fieldwork related to this thesis was conducted during the open-water season: in June and August 2011, and in May, July, and September 2012. Field campaigns also included a snow survey (March 2012), and spring melt/freshet sampling (April 2012). The analysis of spatiotemporal variability of water isotopes and geochemistry in the years 2011-2012 yielded: i) a characterization of baseline conditions from which perturbations can be assessed, and ii) evidence of connectivity among landscape units. No evidence for elevated concentrations of nitrogen related to the amendment experiments was found in 2011 or 2012. The baseline characterization and annual monitoring did show increasing concentrations of inorganic ammonium with increasing depth associated with increasing solute concentrations: average concentrations of inorganic ammonium were 23 mg/L at deepest sampling locations (7 m) at ML bog and ML fen landscape units. These ammonium concentrations in porewaters, given a porosity of 0.90 for peatlands, constitute a store of ammonium that may be a significant source of nitrogen if the hydrology is altered due to co-occurring changes in vegetation (due to, for example, elevated nitrogen inputs), climate and/or landuse. Hydrologic connectivity at JPH is likely driven by topography. Hydraulic head in 2011 and 2012 field seasons showed that flow persisted from the upland to the fen. The consistent and distinct geochemical signatures and isotopic labelling of mid-depth and deep groundwater samples of fen and upland landscape units is consistent with such a stable groundwater continuum. Near-surface water samples at JPH fen however varied hydrogeochemically in response to seasonal changes in precipitation inputs, water levels, and biogeochemical productivity. At ML, hydrological connectivity is a function of antecedent moisture conditions (which determines run-off) and low and variable (10-6 to 10-9 m/s) hydrological conductivity of the peatland substrate (which may result in lateral flow where hydraulic head shows potential for vertical re- or discharge). Near-surface samples showed greater temporal than spatial variability as snowmelt inputs, variations in antecedent moisture conditions and seasonal changes in biogeochemical process rates affected nutrient and solute concentrations. In contrast, shallow, mid-depth and deep samples showed greater spatial than temporal variability. The spatial distributions of parameters could be associated to some degree with vegetation, distance along a surficial flowpath, or depth to mineral substrate or distance from the upland/edge transition. / Graduate / 0996 / 0388 / 0425 / cbkusel@yahoo.ca
66

Connectivity

Angelopulo, George 21 May 2014 (has links)
No description available.
67

Audience connectivity in orchestral performances

Lindblom, Shari January 2009 (has links)
With the general global decline in the popularity and profitability of traditional orchestras, ways to build new audiences, develop new repertoires and create new networks and business partnerships are being explored. The aim of this thesis is to analyse the various elements of a proposed Orchestral Sustainability Framework and determine if and how these elements contribute to an increased audience connection with the music performance experience. Three main elements are explored in this Orchestral Sustainability Framework: 1. Social aspects of audience connection such as performer/audience interaction and ways of emotional engagement 2. Artistic aspects of audience connection such as the impact of poly-stylistic genres, blend of instruments and sounds and the importance of inter-sensory perception using visuals, theatre and music 3. Economic aspects of audience connection such as networking with business partnerships, impact of branding and marketing and the importance of distribution channels Audience reactions are central to this approach. Audiences from a variety of existing orchestral models have been researched through case studies, interviews, surveys, focus groups and participant observation. An orchestra, formed specifically for this project, performed to selected audiences and at the Brisbane Festival of Arts in 2006 and is now achieving commercialisation. The style of this orchestra is characterised by audience and performer interactivity, theatrical staging, visuals, spontaneity and less formality. Research has been conducted on this orchestral model, with contributions from the musicians, directors, producers, promoters and audiences. The research hypothesis proposes that a greater connectivity with the audience results in a more sustainable product, where sustainability is indicated by the orchestras’ ability to generate a sufficient amount of box office revenue and sponsorship. A variety of different models are considered which demonstrate orchestras that can achieve their mission of satisfying their audience, while being financial viable. The findings from the literature and the case studies clearly demonstrate the importance of many elements in the sustainability framework to achieve a greater level of audience connection with the orchestra.
68

Informing an integrated and sustainable urbanism through rapid, defragmented analysis and design

White, Marcus, marcuspg@gmail.com January 2010 (has links)
Urban design has splintered into increasingly narrow specialist disciplines since the mid Twentieth Century. Traffic engineers, statutory planners, civil engineers, landscape architects and architects each make specific but isolated contributions to urban design frameworks. Each consultant documents their position predominantly through text and two dimensional representations, occasionally with specious perspective images produced by a hand rendering specialist. This fragmented and sequential design approach inadequately addresses contemporary urban agendas, practice constraints or the potential of digital design techniques, particularly in light of increasing fears of an imminent environmental crisis and peak oil, and concerns for health, amenity and accommodating an increasingly urbanised population. The aim of my thesis is to identify and address disparities between contemporary urban design practice and society's prevailing urban agendas for integrated and sustainable cities. The hypothesis tested by my thesis is that the gulf between prevailing urban agendas of society and urban design can be reduced by developing a 'defragmented' design approach that uses rapid, parametric, four-dimensional, digital analysis and design techniques, which build upon software commonly available within the industry. This hypothesis has been tested in four ways: firstly through the analysis of urban agendas, design techniques and urban design paradigms, in both historic and contemporary contexts; secondly by identifying currently available technologies with the potential for adaptation and customisation; thirdly by development of new digital techniques; and finally by testing this defragmented approach on both simplified models and various case studies within an urban design practice as part of the embedded research program. Techniques I have developed and tested as part of the approach fit into four categories: firstly pedestrian connectivity - walkability and accessibility; secondly daylight amenity assessment; thirdly visual impact analysis assessing urban form visualisation, generation and composition; and finally feasibility modelling, including linked data yield analysis. I have evaluated the success of the approach in these studies with regard to practice constraints (time and budget) and contemporary society's pr evailing urban agendas. My rapid, defragmented design approach has resulted in new techniques shown to be used quickly and concurrently 'in-house' contributing to the urban design process, whilst meeting fee budgets and project deadlines. I have demonstrated that issues that are currently difficult to solve using the constraints of conventional planning techniques can be addressed more effectively than they are currently, whilst avoiding the considerable expense of specialised hardware/software or the appointment of additional consultants. My thesis concludes that the rapid, defragmented approach can demonstrably yield more synergistic urban design responses. The inherently flexible approach can be tailored for a myriad of different urban design scenarios, as well as potentially other disciplines. The defragmented approach can expand the realm of urban designers and increase their contribution in the generation and advocacy of sustainable planning policy and reduce the disparities between contemporary urban design practice and society's need for integrated and sustainable cities.
69

Synaptic connectivity of visual pathways in the primate retina

Jusuf, Patricia Regina January 2005 (has links) (PDF)
The retina contributes to visual submodalities by anatomically and functionally distinct parallel pathways. In this thesis, the synaptic connectivity of cell types in parallel visual pathways in marmoset (New World primate) and macaque (Old World primate) retinas are studied. / In Chapter 1 the main anatomical and physiological properties of parallel pathways in the primate retina are described. / Diffuse bipolar (DB) cells receive synaptic input from multiple cones and provide output to ganglion cells, but their synaptic connectivity in the inner plexiform layer is not well understood. In Chapter 2, the stratification and synaptic connectivity of DB6 axon terminals are described. It is shown that the axons of DB6 cells stratify in the same region as rod bipolar cells and blue-OFF/yellow-ON ganglion cells. The majority (86%) of their synaptic output is onto amacrine cells; only 14% goes to ganglion cells. The DB6 cells may synapse with amacrine cells in the rod pathway and the blue-OFF/yellow-ON ganglion cells. / The inhibitory neurotransmitter glycine is used by about half of all amacrine cells. Using immunohistochemical methods, the experiments in Chapter 3 investigated whether different bipolar and amacrine cell types differ with respect to the expression of glycine receptor (GlyR) subtypes. Postembedding electron microscopy showed the postsynaptic location of the a1, a2 and a3 subunits of the GlyR. Double immunofluorescence demonstrated that firstly, the three a subunits are clustered at different postsynaptic sites, and secondly that OFF bipolar types are predominantly associated with the a1 subunit, whereas ON bipolar types are predominantly associated with the a2 subunit. This shows that different amacrine cell types at synapses express different types of glycine receptors. / The midget pathway is involved in processing red-green colour vision and high spatial acuity. In Chapter 4, the synaptic connectivity of OFF midget bipolar cells was investigated in the central retina of marmosets and macaque. The OFF midget bipolar cells and their synapses were identified immunohistochemically. Midget ganglion cells in marmosets were retrogradely labelled from the parvocellular layers of the dorsal lateral geniculate nucleus. Consistent with previous studies of Old World primates, it is shown that in marmoset the midget bipolar cells contact midget ganglion cells at a ratio of 1:1. The number of output synapses was quantified for 330 OFF midget bipolar cells (n = 104, dichromatic marmoset; n = 108, trichromatic marmoset; n = 118, macaque). The average number of output synapses per axon terminal was comparable for all animal phenotypes. In all animals the number of output synapses per axon terminal showed a unimodal distribution. Our results suggest that the midget circuitry in central retina is comparable in dichromatic and trichromatic animals. / The midget pathway in mid-peripheral retina has been suggested to involve colour selective wiring of midget bipolar to midget ganglion cells. The question whether there is anatomical evidence for colour selective wiring was addressed in Chapter 5, in double labelled preparations of marmoset retina where OFF midget bipolar and OFF midget ganglion cells were identified. The relationship of the bipolar axon terminal mosaic and the dendritic fields of midget ganglion cells was analysed. No anatomical evidence for colour-selective connectivity in the inner retina of marmosets was found.
70

Neuroplasticity hypothesis of the mechanism of electroconvulsive therapy: a proton magnetic resonance and functional connectivity investigation

Song, Tian Yue 20 June 2016 (has links)
INTRODUCTION: Major depressive disorder (MDD) is characterized by ongoing feelings of guilt, sadness, and memory and cognition impairment. It is a multidimensional illness that affects many functionally integrated pathways of the brain. Understanding the underlying brain dysfunction that gives rise to this complex illness has been challenging, and by extension the search for appropriate treatments. MDD patients who are considered treatment resistant make up the primary population that receives electroconvulsive therapy (ECT). Remarkably, ECT shows a 75% remission rate in this patient population and is considered the “gold standard” treatment for major depression. Although the exact mechanism of its function is unknown, it is well accepted that the induced grand-mal seizure confers its therapeutic effect. The seizure likely has broad effect that somehow corrects the underlying dysfunction in brain circuitry. Here, we specifically examined studies of functional connectivity and metabolite changes. METHODS: Through literature search, we examined six studies in functional connectivity and four studies in magnetic resonance spectroscopy (MRS). RESULTS: Functional Connectivity: Studies have found that after bilateral ECT treatments, patients with major depression showed reduction of functional connectivity (FC) from the left dorsolateral prefrontal cortex (DLPFC) to other cortical and limbic structures. Correlated activity between the superior frontal gyri, middle frontal gyri and angular gyri were significantly increased after ECT. Hyperdeactivation of the orbitofrontal cortex to negative emotional stimuli in patients was decreased, and it was associated with improvement in depressive symptoms. Regional activity in the subgenual anterior cingulate cortex (sgACC) and functional connectivity between the sgACC and left hippocampus in treatment naïve patients after ECT were increased and correlated to reduction of depressive symptoms. Reduced connectivity between the amygdale and sgACC and increased connectivity between the amygdale and DLPFC was found by sequential assessments over a course of ECT treatments. Lastly, ECT increased the functional connectivity between DLPFC and the default mode network. MRS: Studies found decreased levels of glutamate or glx (glutamate/glutamine/ GABA) in patients in the anterior cingulate cortex and dorsolateral prefrontal cortex (DLPFC) compared to healthy controls. Additionally, it was found that glx levels increased after ECT treatments and that this increase was only in those who responded to treatment. Lastly, GABA level increased after ECT treatment in the occipital cortex. Discussion: Results from functional connectivity and brain metabolite studies in patients with major depression point to induced neuroplasticity as part of ECT’s therapeutic mechanism. Remodeling connectivity and mediating metabolite changes both will require modifications at the synaptic level. The wide spread changes seen in several different brain regions that have been implicated in depression further suggests that ECT’s effects are both highly specific and broad. CONCLUSION: Electroconvulsive therapy has consistently demonstrated impressive efficacy among the most severely depressed patients and is known to produce widely distributed effects in the brain. However, this also makes assessing its therapeutic mechanism challenging. Magnetic resonance imaging studies assessing functional connectivity and brain metabolite levels have demonstrated that ECT likely produces neuroplastic changes to remodel aberrant connectivity and dysfunctional excitatory and inhibitory neurotransmission in cortical and limbic areas. Although these findings should be interpreted with caution, this field of research has provided an unprecedented opportunity to examine the living brain in great detail. Further studies with larger sample sizes and improved technical specifications will likely yield greater results.

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