Hybrid renewable energy systems (HRESs) have become increasingly popular, especially for isolated regions. This thesis describes the design of a HRES for the isolated Ha'apai Island group in Tonga following a devastating cyclone which happened in 2014. Several renewable power generation and storage possibilities were investigated; solar, wind and battery were found to be feasible for Ha'apai. The conceptual design of a new energy storage system, the Subterranean Ocean Energy Storage System (SOESS), is also discussed as a possible alternative to batteries and a more viable substitute for an ocean renewable energy storage (ORES) system. For the proposed Ha'apai system, the optimum system configuration (solar 450 kW, wind 550 kW, battery 1,216 kAh/4,864 kW) with 90% renewable penetration was obtained using the HOMER software. Based on the optimum system configuration, load flow simulations of both the previous system and the proposed HRES were performed in DIgSILENT PowerFactory. The results of the load flow analysis show that all the transformers and transmission lines in both systems operate safely in both peak and nominal load conditions, and that the voltage levels of all LV buses are within the acceptable range of ±5%. The detailed system topology of the proposed HRES is discussed from the system implementation point of view. A unique set point control algorithm for the start-up/shut-down of the diesel generators was developed. The system dynamic performance was simulated according to the control logic during the three main switching events in DIgSILENT PowerFactory. The dynamic simulation results indicate that the proposed system would operate safely with acceptable voltage and frequency oscillations. This thesis could be used as a template for the design of other isolated HRESs with high renewable penetrations.

No description available.

This thesis is an exploratory work into the migration and settlement experiences of highly skilled Turkish migrants who have settled in Canada. It is a qualitative study conducted with sixteen immigrant respondents living in Halifax and Toronto. The focus of this work is on the role of networks, specifically in shaping these migrants’ migration routes, developing belongings and reworking identities. While it is the feminist theory that informs this study, I use the intersectional theory as the theoretical framework. It has been found that the social class not only arose as a central factor that influenced these migrants’ experiences but it also affected the interplay between ethnicity and gender. The findings are analyzed with the help of current literature on globalization and international migration theories. The similarities and differences between the Halifax and Toronto respondents are also highlighted in order to inform provincial and national policies.

The manifestation of HIV-1 infection is different in children and adults. Most of the children who acquire HIV perinatally progress to disease within the first two years of life, while adults can remain asymptomatic for up to ten years. However, a small minority group of children can control the virus for years in the absence of antiretroviral therapy. We characterized CD8+ T cell responses critical for the containment of HIV infection in a cohort of infants HIV infected from birth using IFN- γ ELISPOT, multicolour flow cytometry and viral sequencing of the Gag protein. We investigated whether the age at the time of infection, specificity and functionality of the generated responses, genetic make up and the maternal immune responses to HIV, influenced disease progression in the child. We found that the majority of in-utero infected infants mounted CD8+ T cell responses from the first days of life. In contrast to chronically infected children or adults, the specificity of the initial response in acutely infected infants was directed towards Env and Rev proteins and CD4+ T cell responses were minimal during the first 6 months of life. Slow progression to disease was associated with possession of one of the protective HLA-B alleles by either the mother or the child (P=0.007) and targeting of Gag epitopes presented by the protective HLA-B alleles. Mothers who expressed protective alleles but whose children did not possess these alleles, transmitted less fit viruses that benefited their children. Furthermore, slow progressor children had more polyfunctional CD8+ T cell responses in early infection when compared to rapid progressors (P=0.05). The ability of infants to induce CD8+ T cell responses early in life is encouraging for vaccine interventions. The differences in the specificity of the initial responses between adults and children, insufficient priming of these responses as a result of minimal CD4+ T cell help during infancy and possession of non-protective HLA alleles shared between mother and child, may explain the rapid disease progression generally noted in most infants. However, slow progression to disease in the minority group of children may be attributed to functional capacity of the CD8+ T cells generated by the child, mediation by protective HLA alleles, acquisition of low fitness viruses from the mother or de novo attenuation of the virus by the child’s own immune responses. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.

Reverse transcription of human immunodeficiency virus type-1 (HIV-1) is primed by cellular tRNALys3, which is selectively packaged into viral particles where it is bound at its 3' terminus to a complementary sequence of viral RNA termed the primer binding site (PBS). In addition to the PBS, other regions within the viral genome also interact with tRNALys3. Initiation of HIV-1 reverse transcription requires specific recognition of the viral genome, tRNA primer, and reverse transcriptase (RT). In this work, we study the important role played by the initiation complex in the initiation of HIV-1 reverse transcription. An "A-rich loop" located upstream of the PBS has been shown to interact with the anticodon loop of tRNALys3 and deletion of this A-rich loop caused diminished viral replication fitness. We have now studied the mechanisms involved in the altered replication capacities of the deletion-containing viruses in the context of both wild type HIV-1 and viruses also containing the M184V substitution in RT. We found that the M184V mutation in RT compromises the ability of deletion-containing viruses to restore wild-type replication. Further biochemical study indicates that both the M184V mutation in RT and deletion of sequences upstream of PBS caused diminished viral replication fitness by compromising the efficiency of reverse transcription initiation. / Since the initiation of DNA synthesis was shown to be a highly specific process, it represents a potential target for the development of novel antiviral agents. We developed strategies for inhibition of the HIV-1 replication via interference with the tRNALys3/viral RNA complex. To target primer tRNALys3, we employed oligodeoxyribonucleotides (ODNs) that are complementary to different parts of the tRNA primer. To target viral RNA, we devised a tRNALys3-like molecule, termed tRNA Lys*, that contained sequence alterations that direct initiation from a region distant from the natural PBS, designated PBS*. PBS* is involved in the formation of the natural tRNA/PBS complex and binding of tRNALys* was shown to interfere specifically with the initiation of reverse transcription. Inhibition of the synthesis of (-) strand strong-stop DNA was achieved successfully with both strategies by interfering with the formation of the initiation complex.

Thesis (Ph.D.)--Kent State University, 2007. / Title from PDF t.p. (viewed Mar. 11, 2009). Advisor: Miguel Quiñones-Mateu. Keywords: HIV/AIDS, drug discovery, small molecule library screening, characterization of new antiretroviral drugs, highly active antiretroviral therapy. Includes bibliographical references (p. 180-200).

Thesis (M.A.)--Kent State University, 2009. / Title from PDF t.p. (viewed April 16, 2010). Advisor: John Gunstad. Keywords: HIV; executive function; adherence. Includes bibliographical references (p. 41-54).

“Cartas al editor” / Revisión por pares

Master of Science / Department of Diagnostic Medicine/Pathobiology / Alison Paige Adams / Avian influenza (AI) is a zoonotic disease that has garnered much attention in recent years due to its detrimental effects on poultry, producers and potentially human health. This disease can be extremely fatal to domestic poultry, killing as high as 90-100% of the flock. This virus has the potential to cause devastation to and loss of entire flocks. AI is typically spread between wild fowl and domestic poultry with a zoonotic potential to also affect human health as well as other animals. Its spread also has a massive economic impact due to the decreased amounts of available poultry products to consumers around the world. This report will examine the worldwide history and epidemiology of highly pathogenic avian influenza (HPAI). In the last ninety-two years, there have been five recorded outbreaks of HPAI in the United States (US). Globally, notable outbreaks have occurred in Italy (1997-2001), the Dutch region of Europe (2003), Canada (2004), and more recently, in Asia. Preventative measures will be examined in this report. In particular, biosecurity, quarantine, surveillance, and eradication are some of the most widely recognized and accepted ways to help prevent and control HPAI outbreaks. However, none of these methods are failsafe strategies to completely prevent or control the spread of HPAI. This report will focus on an additional preventative measure - currently available and potential future vaccination programs. There is a global shift toward procuring poultry that are AI-free as well as unvaccinated for AI. This is, in part, due to the limitations of currently available vaccines in completely ridding poultry of this disease. Vaccinations may reduce the amount of virus in infected birds, but this does not prevent birds from becoming infected. When addressing the control and eradication of HPAI, some future challenges include viral mutations, intermingling of domesticated and wild birds, and vaccine development. Because of the current limitations of vaccines and future challenges in controlling the spread of infection, there is no one single solution to this problem. It will require a multi-faceted approach.

Magister Public Health - MPH / The government of Namibia established a comprehensive HIV/AIDS treatment and care programme in 2002. This programme provides anti-retroviral treatment to all eligible HIV patients in the public health sector. The antiretroviral treatment programme in Keetmanshoop started in October 2003. Adherence to treatment regimes in HIV care is a key factor in determining clinical outcomes and is associated with improved survival among HIV and AIDS patients. Sustained high levels of adherence (95% or more) are essential for the success of highly active antiretroviral therapy (HAART). Maintaining high adherence levels is therefore a major concern in HIV/AIDS treatment programmes. This study investigated adherence to HAART among patients in the Keetmanshoop antiretroviral therapy (ART)clinic and the factors that affect adherence.Aim of the research The aim of the research was to describe adherence to HAART and factors influencing adherence among patients in Keetmanshoop ART clinic, Namibia.Objectives: 1. To describe levels of adherence to HAART amongst clients at Keetmanshoop ART clinic. 2. To assess the changes in CD4 count and body weight of clients on HAART over a 12 month period.3. To assess factors associated with adherence to HAART.4. To analyse associations between CD4 count and adherence. 5. To analyse associations between changes in body weight and adherence. Methodology: A quantitative descriptive cross-sectional survey was used. The study population included all clients 18 years and above, who were on HAART for one year or more at the Keetmanshoop clinic. One hundred and six clients participated in the study. Data was collected through an interview with the participants and a review of clinical records. Results: Most respondents had good adherence levels; with 86.1% reporting optimal adherence levels.The respondents also showed an increase of median CD4 counts from 126 cells/μl at baseline to 304 cells/μl at 12 months and an increase in body weight from an average of 50kg at baseline to an average of 57kg at 12 months. Adherence levels were found to have an impact on CD4 cell counts and on body weight, with respondents who had sub-optimal adherence experiencing a drop in median CD4 cell counts and median body weight by 12 months.Living far from the clinic (>10km) was found to be the only factor significantly associated with sub-optimal adherence.Conclusion: The study showed a positive correlation between adherence levels and CD4 cell counts and body weight gain. In the absence of viral load, CD4 cell count testing can be used as a measure of adherence. Though most respondents appear to be adhering well to HAART, a sub-optimal adherence rate of >10% is a concern for the Keetmanshoop ART programme and will need to be addressed. There is a need for further research to determine the level of default or attrition from HAART in the programme