Spatial analysis and efficiency of systematic designs in intercropping experiments.

Thesis (M.Sc.) - University of Natal, Pietermaritzburg, 2002In studies involving intercropping plant populations, the main interest is to locate the position of the maximum response or to study the response pattern. Such studies normally require many plant population levels. Thus, designs such as spacing systematic designs that minimise experimental land area are desired. Randomised block designs may not perform well as they allow few population levels which may not span the maximum or enable exploration of other features of the response surface. However, lack of complete randomisation in systematic designs may imply spatial variability (largescale and small-scale variations i.e. trend and spatial dependence) in observations. There is no correct statistical method laid out for data analysis from such designs. Given that spacing systematic designs are not well explored in literature, the main thrusts of this study are two fold; namely, to explore the use of spatial modelling techniques in analysing and modelling data from systematic designs, and to evaluate the efficiency of systematic designs used in intercropping experiments. Three classes of models for trend and error modelling are explored/introduced. These include spatial linear mixed models, semi-parametric mixed models and beta-hat models incorporating spatial variability. The reliability and precision of these methods are demonstrated. Relative efficiency of systematic designs to completely randomised design are evaluated. The analysis of data from systematic designs is shown be easily implemented. Measures of efficiency that include <pp directed measures (A and E criteria), D1 and DB efficiencies for regression parameters, and power are used. Systematic designs are shown to be efficient; on average 72% for A and E- efficiencies and 93% for D1 and DB efficiencies. Overall, these results suggest that systematic designs are suitable and reliable for intercropping plant population studies

Assessing risk of HIV and hepatitis C among people who inject drugs in East Africa: findings from a rapid assessment

Rapid assessment cross-sectional surveys and qualitative interviews were conducted among people who inject drugs (PWID) in Burundi and Uganda, as well as key informants working with drug users, to assess risk associated with HIV and hepatitis C (HCV). A total of 127 PWID were recruited in Burundi and 125 in Uganda of which the majority were male and aged between 24 and 26 years. Blood samples were collected in Burundi to test for antibodies to HIV, HCV and B Surface Antigen (HBsAg). Heroin was mainly injected in Uganda and Burundi with a small minority injecting crack/cocaine. Half of participants in Burundi, and 86% in Uganda had been HIV tested. The minority had been tested for HCV in any site (5-7%). HIV prevalence from the serological testing in Burundi indicated that 10% tested positive for antibodies to HIV, 6% to HCV and 9% to HBsAg. Qualitative data suggested that structural factors including costs of needle/syringes as well policies prohibiting pharmacies selling injecting equipment to PWID were related to reuse and sharing of needles/syringes among PWID, despite awareness HIV transmission risk. Police arrest was common in Burundi and Uganda and the use of bribes by police compounded existing high levels of poverty. Findings accentuate the need for policy shifts to enable easier access to clean injecting equipment, increased availability of HIV and HCV testing and increased access to affordable drug treatment and introduction of opioid substitution therapy. Specific attention is needed to the potential for sexual transmission of HIV among this population

Utilization of sexual and reproductive health services among young people in refugee settings in Uganda

There is a considerable high level of unmet need for reproductive health services among refugees. Yet, there is limited research about the provision and utilization of sexual and reproductive health (SRH) services among young people in refugee settings. Drawing on a sample of 575 young refugees (15–24 years) from a cross-sectional survey, this study aims to fill this gap by identifying the factors associated with SRH utilization among young people living in refugee settings in Northern Uganda. The utilization of SRH services at the health facilities was significantly different between female and male young people after adjusting for all other variables (aOR = 2.46, 95% CI, 1.58, 3.84). Young people who were not living in a marital union (aOR = 0.38, 95% CI, 0.20, 0.71), or held inequitable gender norms about services (aOR = 0.28, 95% CI, 0.12, 0.66) had about a third of the odds of utilizing SRH services. Young women with comprehensive knowledge about contraception, modern contraceptives, and HIV and STI prevention, had more than twice the odds of utilizing SRH services (aOR = 2.23, 95% CI, 2.67, 6.90). There is need to integrate social norm measurements and social norm change strategies in strategies for promoting utilization of SRH services among refugees in low-income countries especially in Ugand

The sexual behavior of young people living with a disability: Findings from the KAP study in Northern Uganda

IntroductionYoung people living with disability form one of the most vulnerable population groups globally. There is limited information on the use of SRH services among young people living with a disability.MethodsThis analysis is based on household survey data among young people. Drawing on a sample of 861 young people living with a disability (15 -24 years), we investigate the sexual behaviour, and identify the risk factors associated with sexual behavior of young people living with a disability. Multilevel logistic regression was used.ResultsResults indicate that risky sexual behaviour was associated with alcohol consumption (aOR = 1.68; 95%CI: 0.97, 3.01), having limited knowledge of HIV and STI prevention methods (aOR = 6.03; 95%CI: 0.99, 30.00), and low life skills (aOR = 4.23; 95%CI: 1.59, 12.87). The odds of not using a condom at last sex were significantly higher among in-school young people than out of school young people (aOR = 0.34; 95%CI: 0.12, 0.99).DiscussionTargeted interventions aimed at reaching out to young people living with a disability should consider their sexual and reproductive health needs, barriers, and facilitators. Interventions can also promote self-efficacy and agency of young people living with a disability in making informed sexual and reproductive health choices

How Self-Efficacy and Agency Influence Risky Sexual Behavior among Adolescents in Northern Uganda

Background: Risky sexual behaviors remain common among adolescents regardless of those with comprehensive knowledge of safer sex practices. Self-efficacy has been shown to have a positive relationship with safer sex practices. Thus, investigating self-efficacy, and enhancing it to agency is important. The current study explores the predictors of self-efficacy for avoiding risky sexual behaviors and what limits agency among sexually active adolescents (15–19 years) in Northern Uganda. Methods: The study consisted of a sub-sample of 396 sexually active adolescents (145 in school, 251 out of school) interviewed as part of a household survey for the program on Advancing Sexual Reproductive Health and Rights in Northern Uganda. Poisson and Poisson regression models with survey weights were implemented in Stata. Results: A total of 94% of male and 64% of female adolescents reported self-efficacy to avoid unsafe sex, including using condoms and avoiding multiple sexual partnerships or transactional sex. At multivariable analysis, a higher proportion of adolescents who listened to a radio or television program about sexual and reproductive health within the past 12 months had self-efficacy as compared to others (PR = 1.13, p-value = 0.002). Similarly, higher proportions of adolescents who knew all the sexual and reproductive health (SRH) rights (PR = 1.33, p-value = 0.007) and who had comprehensive knowledge about pregnancy, prevention of sexual transmission infections, and sources of SRH services (PR = 1.24, p-value = 0.013) had self-efficacy as compared to others. However, among those who reported self-efficacy, 42% of the girls and 53% of the boys could not uphold their self-efficacy in actual sexual encounters in the past 12 months. Partner’s refusal or girls’ fear to ask their sexual partner to use a condom were commonly cited reasons. Alcohol consumption was associated with failure to act on one’s self-efficacy (RR = 0.74, p-value = 0.048). Conclusions: Programs should target self-efficacy beliefs and attempt to enhance them into agency by increasing positive and decreasing negative expectations associated with risky sexual behavior