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Stormwater Retention Ponds: Hydrogen Sulfide Production, Water Quality and Sulfate-Reducing Bacterial KineticsD'Aoust, Patrick Marcel January 2016 (has links)
Stormwater retention basins are an integral component of municipal stormwater management strategies in North America. The province of Ontario’s Ministry of the Environment and Climate Change obligates land developers to implement stormwater management in their land use and development plans to mitigate the effects of urbanization (Bradford and Gharabaghi, 2004). When stormwater retention ponds are improperly designed or maintained, these basins can fail at improving effluent water quality and may exasperate water quality issues.
Intense H2S production events in stormwater infrastructure is a serious problem which is seldom encountered and documented in stormwater retention ponds. This study monitored two stormwater retention ponds situated in the Riverside South community, Ottawa, Ontario, Canada for a period of 15 consecutive months to thoroughly characterize intense hydrogen sulfide (H2S) production in a stormwater retention pond under ice covered conditions during winter operation and during periods of drought under non-ice covered conditions during the summer.
Field experiments showed a strong relationship (p < 0.006, R > 0.58, n = 20+) between hypoxic conditions (dissolved oxygen (DO) concentration < 2 mg/L) and the intense production of H2S gas. Ice-capping of the stormwater ponds during winter severely hindered reaeration of the pond and led to significant production of total sulfides in the Riverside South Pond #2 (RSP2), which subsequently resulted in the accumulation of total sulfides in the water column (20.7 mg/L) during winter in this pond. There was a perceived lag phase between the drop in DO and the increase in total sulfides near the surface, which was potentially indicative of slow movement of total sulfides from the benthic sediment into the water column. These high-sulfide conditions persisted in RSP2 from early January 2015 until the spring thaw, in mid-April, 2015. Riverside South Pond #1 (RSP1), the reference pond studied in this work, showed significantly less production of total sulfides across a significantly shorter period of time. Analysis of the microbial communities showed that there was little change in the dominant bacterial populations present in the benthic sediment of the pond demonstrating significant total sulfide production (RSP2) and the pond that did not demonstrate significant total sulfide production (RSP1). Additionally, it was found that locations with the most accumulated sediment had the highest propensity for the production of H2S gas. Furthermore, there was no perceivable community shift in the two ponds throughout the seasons, indicating that the sulfate-reducing bacteria (SRB) in stormwater benthic sediment are ubiquitous, exist in an acclimatized microbial population and are robust. Study of the microbial abundances revealed that SRB represented approximately 5.01 ± 0.79 % of the microbes present in the benthic sediment of RSP2. Likewise, in the stormwater pond which did not experience intense H2S gas production, RSP1, 6.22 ± 2.11 % of microbes were of the SRB type, demonstrating that H2S gas production does not correspond to higher concentrations of SRB or the proliferation of dominant species, but rather is a symptom of increased bacterial activity due to favourable environmental conditions.
In addition, this work also covers the kinetics of sediment oxygen demand (SOD), ammonification and sulfate-reduction, and attempts to understand the processes leading to H2S gas production events.
In doing so, it was observed that kinetics obtained full-scale field studies were greater than in laboratory kinetic experiments. Laboratory experiments at 4°C identified total SOD, ammonification and sulfate-reduction kinetics to be 0.023 g/m2/day, 0.027 g N/m2/day and 0.004 g S/m2/day, respectively. Meanwhile, kinetics calculated from the field study of stormwater retention ponds for total SOD, ammonification and sulfate-reduction were of 0.491 g/m2/day, 0.120 g N/m2/day and 0.147 g S/m2/day, respectively. It is expected that this difference is due to the depth of active sediment influencing the total rates of production/consumption, making area-normalized daily rates of production/consumption (g/m2/day) unsuitable for the comparison of field and laboratory studies, without some scaling factor. This study also measured supplementary kinetic parameters such as the Arrhenius coefficients and the half-saturation coefficient, to add to existing knowledge of sulfate-reduction.
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Geochemical Surface Expression of the Phoenix and Millennium Uranium Deposits, Athabasca Basin, SaskatchewanPower, Michael James January 2014 (has links)
The geochemistry of surface media above two known U deposits were examined to observe any possible dispersion products could be detected from them, and based on these findings, improved geochemical exploration techniques are proposed to reduce cost of finding undiscovered U resources. This study examined the materials overlying the Phoenix deposits, which have indicated resources of approximately 58.2 million lbs U3O8 grading 15 wt% that lie at 400 m depth below surface at the unconformity between the overlying Athabasca sandstones and Paleoproterozoic basement rocks. Aqua regia digestion, ammonium acetate at pH 5 and hydroxylamine leaches revealed U, Pb, Co, Ni, Mo, and W anomalies in humus and U, W and As anomalies in B-horizon soils above the ore zones and the basement location of a deposit-hosting, northeast-trending “WS Hanging Wall” shear zone over a three year period. These metal signatures suggest likely upward transport of metals from the deposits to overlying sandstones, and subsequently into the overlying till and soils.
This study also looked at materials above the Millennium U deposit, which has indicated resources of 68.2 million lbs U3O8 grading 4 wt% at ~750 m depth that occurs along a major fault in granites & metamorphosed pelites of Paleoproterozoic age below the Athabasca sandstones. Soil samples taken over the surface projections of an ore-hosting fault and the ore zone yielded anomalous values in U, Ni, Cu and Pb in aqua regia digestion of humus and U, Cu and Pb values in ammonium acetate leach of pH 5 of B-horizon soils. Hydroxylamine leach did not yield as many anomalies as ammonium acetate leach. Measured 4He/36Ar ratios of gas dissolved in water-filled drill holes were observed to be up to about 700 times the atmosphere value for air-saturated water, revealing the presence of radiogenic 4He that was likely produced from decaying U and released in the groundwater above the deposit. Our results suggest upward migration of metals to surface through porous sandstone and fault systems at Phoenix, and upward migration of metals along faults and He gas at Millennium. Both studies indicate the importance of the traverse method of sampling over targets perpendicular to the last major ice-flow event to discern U deposits that are defined by other means.
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20th Anniversary Update of the Ottawa Decision Support Framework: Evidence Syntheses of Needs Assessments and Trials of Patient Decision AidsHoefel, Lauren 25 October 2019 (has links)
Purpose:
To synthesize evidence on decisional needs assessments and patient decision aid (PtDA) trials based on the Ottawa Decision Support Framework (ODSF) in order to validate the concepts and test the main assertion in the ODSF.
Decisional Needs:
The systematic review studies (n=45) validated all of the decisional needs identified in the ODSF. Nine new manifestations of ODSF decisional needs emerged (e.g. information overload, unreceptive to information/deliberation, relationship barriers with practitioner).
PtDAs:
The sub-analysis identified 24 ODSF PtDA trials. Compared to usual care, ODSF PtDAs improved decision quality, addressed decisional needs and reduced decision delay. Further evaluation is needed on downstream impacts of these improvements on decision-making.
Conclusions:
Using Walker and Avant’s theory testing steps, the integrated findings from the systematic review and sub-analysis validated the ODSF decisional needs concepts and tested the main assertion in the ODSF (that PtDAs address decisional needs and improve decision quality).
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Inside the Black Box of Jail: Barriers to Change at the Ottawa-Carleton Detention CentreMaadarani, Mariah 07 December 2020 (has links)
The Ottawa-Carleton Detention Centre (OCDC) is notorious for its austere conditions of confinement and human rights violations. In response to widespread criticism, the Ontario provincial government created a dedicated task force in 2016 to address longstanding issues at the jail. To date, little research has examined how OCDC has maintained these deplorable conditions of confinement despite concerted effort to improve them. Drawing on Mathiesen’s (1990) neutralization techniques, this thesis reveals the tactics used by government officials and jail functionaries to maintain the status quo at OCDC and stifle transformative change by comparing task force recommendations with their ensuing implementation. Through a qualitative content analysis of the OCDC task force progress reports, trend analyses, Ombudsman, Community Advisory Board, Independent Review of Corrections, and Jail Accountability & Information Line reports documenting issues at OCDC, I demonstrate how the Ontario provincial government and OCDC administration (a) refer to competing demands, higher authority, policy and procedure, or safety and security as excuses for not instituting changes, (b) define policy alternatives as irrelevant or impossible to implement, (c) postpone implementation of measures for not being developed enough or possible now, as well as (d) puncture and (e) absorb policy alternatives to uphold the status quo and impede transformative change. In doing so, I expose the provincial penal system’s proclivity to ‘finish’ (Mathiesen, 1974) alternatives that threaten the current system, thereby gutting new ideas of their ability to generate meaningful social change. The insights provided by this thesis help lay the groundwork for future critical criminological research to examine the barriers to social change in the penal field on a sub-national, national, and international scale.
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Relationship Between the Sources of Sexual Reproductive Health Messages and the Sexual Agency of Second-Generation Migrant Ottawa Women: A Retrospective Cross-Sectional StudyAli, Amina 13 January 2022 (has links)
The development of sexual agency in young women is essential. Adolescence can be a confusing time for many youths as they are forging their way into adulthood. This confusion can be especially difficult for second generation migrants (SGM), a group that are often faced with different cultural spheres when discussing sexual and reproductive health (SRH) topics. This exploratory retrospective study examined the relationship between their cultural affiliations, the sources of SRH provided to SGM girls during adolescence (10-17 years old) and their subsequent level of sexual agency (18-24 years old) as young adults. The sources examined were parents, siblings, friends/peers, teachers and the media. Sexual agency was measured using the Sexual Assertiveness Questionnaire (SAQ) and the Sexual Affect Scale. A small sample of 105 respondents participated in the online survey. The participants reported the media to be their highest-ranking source of actual SRH messages and friends/peers as their preferred source. SRH messages provided by parents and friends/peers were significantly negatively correlated with the overall sexual agency of the participants. The results also present the individual associations between the 14 statements for each of the sources and the sexual agency of the participants. Not being ready for sex was the most cited reason for abstinence and was significantly positively associated with sexual agency.
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Impacts of nutrient loads on the invasion potential of Butomus umbellatus L. on Ottawa National Wildlife Refuge diked wetlandsForstater, Erica L. 10 August 2020 (has links)
No description available.
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Streambank stability in open channel drainage in the Ottawa-St. Lawrence lowlandsMackie, Rob January 1988 (has links)
No description available.
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The Local-National Hybrid Showcase Scorecard: A Methodology for Evaluating the Hybrid (Local and National) Showcase Identities of Ottawa-based Professional English-Language Theatre OrganizationsPaterson, Thalia 19 July 2022 (has links)
The city of Ottawa, Ontario is neither an independent municipality nor solely Canada’s national capital. Ottawa instead sustains a hybrid state of being where the characteristics and cultural assets specific to the city’s two roles intertwine to generate its unique identity as a “national and local,” or “hybrid,” artistic showcase. As the identity of a place evolves from the practices and individual identities of all those involved with the environment, Ottawa’s self-stated “hybrid showcase” identity can be investigated through a study of the professional English-language theatre organizations operating within city limits. Ergo, this thesis introduces a methodology for conducting data-driven assessments of theatre organizations’ local, national, or hybrid artistic showcase identities, known as the Local-National Hybrid Showcase (LNHS) Scorecard. Using fifteen indicators, the LNHS Scorecard assesses the 2018 artistic programming and programming-adjacent operations of seven Ottawa-based theatre organizations. The results of said assessments illustrate the qualitative value of each organization’s showcase hybridity and identify any perceived preferences towards local or national stakeholders therein. Findings generated by applying the LNHS Scorecard methodology to the selected case studies suggest that as of December 31st, 2018, seven of Ottawa’s professional English-language theatre organizations embraced hybrid (local and national) showcase identities. Moreover, the final scores indicate that six of the seven organizations exhibit a weak to moderate preference for activities impacting Ottawa-based stakeholders. Defining Ottawa’s artistic showcase identity according to the combined practices and resulting showcase identities of the individual Ottawa-based theatre organizations upon which the greater artistic showcase depends, the LNHS Scorecard encourages new conversations about the cultural identity of Canada’s capital.
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Mental Health Awareness: University of Ottawa Students’ Knowledge of Mental Health Resources Provided on CampusTabet, Dana 17 August 2023 (has links)
The University of Ottawa (UO) has been dealing with a mental health crisis. The purpose of this study was to evaluate UO students’ knowledge, awareness, and use of mental health services (MHS) and to address limited research on knowledge of on-campus MHS. A cross-sectional online, bilingual, survey was administered to 235 UO students over 18 years old and registered at the university since Fall 2019. Data analysis included descriptive data, categorical analysis, and inductive thematic analysis. Awareness and use of services varied depending on the services in question. 48.9% of students only heard about the services but could not explain them. 57.4% would use a service if in distress and those who would not mainly point to Use of other methods and Lack of information as their reasons. This study contributes to the ongoing efforts of improving UO community’s mental wellbeing.
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An Evaluation of the Secondary School Curriculum of the Harbor Springs SchoolLuce, C. Lester January 1949 (has links)
No description available.
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