• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 329
  • 29
  • 18
  • 12
  • 12
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 442
  • 442
  • 265
  • 233
  • 118
  • 114
  • 113
  • 81
  • 75
  • 71
  • 65
  • 65
  • 58
  • 52
  • 47
  • 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.
181

Ontology-based Semantic Harmonization of HIV-associated Common Data Elements for Integration of Diverse HIV Research Datasets

Brown III, William January 2016 (has links)
Analysis of integrated, diverse, Human Immunodeficiency Virus (HIV)-associated datasets can increase knowledge and guide the development of novel and effective interventions for disease prevention and treatment by increasing breadth of variables and statistical power, particularly for sub-group analyses. This topic has been identified as a National Institutes of Health research priority, but few efforts have been made to integrate data across HIV studies. Our aims were to: 1) Characterize the semantic heterogeneity (SH) in the HIV research domain; 2) Identify HIV-associated common data elements (CDEs) in empirically generated and knowledge-based resources; 3) Create a formal representation of HIV-associated CDEs in the form of an HIV-associated Entities in Research Ontology (HERO); 4) Assess the feasibility of using HERO to semantically harmonize HIV research data. Our approach was guided by information/knowledge theory and the DIKW (Data Information Knowledge Wisdom) hierarchical model. Our systematized review of the literature revealed that synergistic use of both ontologies and CDEs included integration, interoperability, data exchange, and data standardization. Moreover, methods and tools included use of experts for CDE identification, the Unified Medical Language System, natural language processing, Extensible Markup Language, Health Level 7, and ontology development tools (e.g., Protégé). Additionally, evaluation methods included expert assessment, quantification of mapping tasks between raters, assessment of interrater reliability, and comparison to established standards. We used these findings to inform our process for achieving the study aims. For Aim 1, we analyzed eight disparate HIV-associated data dictionaries and developed a String Metric-assisted Assessment of Semantic Heterogeneity (SMASH) method, which aided identification of 127 (13%) homogeneous data element (DE) pairs and 1,048 (87%) semantically heterogeneous DE pairs. Most heterogeneous pairs (97%) were semantically-equivalent/syntactically-different, allowing us to determine that SH in the HIV research domain was high. To achieve Aim 2, we used Clinicaltrials.gov, Google Search, and text mining in R to identify HIV-associated CDEs in HIV journal articles, HIV-associated datasets, AIDSinfo HIV/AIDS Glossary, AIDSinfo Drug Database, Logical Observation Identifiers Names and Codes (LOINC), Systematized Nomenclature of Medicine (SNOMED), and RxNORM (understood as prescription normalization). Two HIV experts then manually reviewed DEs from the journal articles and data dictionaries to confirm DE commonality and resolved semantic discrepancies through discussion. Ultimately, we identified 2,179 unique CDEs. Of all CDEs, data-driven approaches identified 2,055 (94%) (999 from the HIV/AIDS Glossary, 398 from the Drug Database, 91 from journal articles, and a total of 567 from LOINC, SNOMED, and RxNorm cumulatively). Expert-based approaches identified 124 (6%) unique CDEs from data dictionaries and confirmed the 91 CDEs from journal articles. In Aim 3, we used the Protégé suite of ontology development tools and the 2,179 CDEs to develop the HERO. We modeled the ontology using the semantic structure of the Medical Entities Dictionary, available hierarchical information from the CDE knowledge resources, and expert knowledge. The ontology fulfilled most relevant criteria from Cimino’s desiderata and OntoClean ontology engineering principles, and it successfully answered eight competency questions. Finally, for Aim 4, we assessed the feasibility of using HERO to semantically harmonize and integrate the data dictionaries from two diverse HIV-associated datasets. Two HIV experts involved in the development of HERO independently assessed each data dictionary. Of the 367 DEs in data dictionary 1 (D1), 181 (49.32%) were identified as CDEs and 186 (50.68%) were not CDEs, and of the 72 DEs in data dictionary 2 (D2), 37 (51.39%) were CDEs and 35 (48.61%) were not CDEs. The HIV experts then traversed HERO’s hierarchy to map CDEs from D1 and D2 to CDEs in HERO. Of the 181 CDEs in D1, 156 (86.19%) were found in HERO, and 25 (13.81%) were not. Similarly, of the 37 CDEs in D2 32 (86.48%) were found in HERO, and 5 (13.51%) were not. Interrater reliability for CDE identification as measured by Cohen’s Kappa was 0.900 for D1 and 0.892 for D2. Cohen’s Kappas for CDEs in D1 and D2 that were also identified in HERO were 0.885 and 0.688, respectively. Subsequently, to demonstrate the integration of the two HIV-associated datasets, a sample of semantically harmonized CDEs in both datasets was categorically selected (e.g. administrative, demographic, and behavioral), and D2 sample size increases were calculated for race (e.g., White, African American/Black, Asian/Pacific Islander, Native American/Indian, and Hispanic/Latino) and for “intravenous drug use” from the integrated datasets. The average increase of D2 CDEs for six selected CDEs was 1,928%. Despite the limitation of HERO developers also serving as evaluators, the contributions of the study to the fields of informatics and HIV research were substantial. Confirmatory contributions include: identification of effective CDE/ontology tools, and use of data-driven and expert-based methods. Novel contributions include: development of SMASH and HERO; and new contributions include documenting that SH is high in HIV-associated datasets, identifying 2,179 HIV-associated CDEs, creating two additional classifications of SH, and showing that using HERO for semantic harmonization of HIV-associated data dictionaries is feasible. Our future work will build upon this research by expanding the numbers and types of datasets, refining our methods and tools, and conducting an external evaluation.
182

The Association between Social Network Characteristics and HIV Testing Behavior among Users of Illicit Drugs

Gordon, Kirsha S. January 2017 (has links)
INTRODUCTION: Human Immunodeficiency Virus (HIV) infection remains prevalent among the minority and drug using population in the United States. Testing for HIV is an important and cost effective way to reduce HIV prevalence. OBJECTIVE: To assess the HIV testing behavior of people who use non-injected drugs (PWND) and compare it to that of people who use injected drugs (PWID), in order to determine which factors, in terms of social context as well as individual risks, predict HIV testing among the PWND. METHOD: A cross-sectional study of HIV testing behavior of PWND compared to PWID was conducted and the data was analyzed by applying negative binomial regression models. Then, a negative binomial regression using generalized estimating equation (GEE) was employed in order to identify the predictive factors for HIV testing among PWND over a 2-year period. RESULTS: Individuals who reported using injected drugs tended to undergo HIV tests more often compared to those who used non-injected drugs, PR (95% CI) = 1.24 (1.02, 1.51), p = 0.03. The interaction term between injection status and emotional support in relation to HIV testing was significant, 0.75 (0.59, 0.97), p = 0.03. PWID that had access to greater emotional support on average tended to test for HIV less frequently than did PWID with less emotional support. In stratified analyses, emotional support was negatively associated with testing among PWID and positively associated among PWND, though both relationships were borderline significant. HIV testing among users of illicit drugs was dependent on emotional support. According to the GEE models examining the factors predicting HIV testing among PWND, sexually transmitted infections, non-injected heroin use, being in drug treatment, engagement in sexual transactions, and instability in drug networks were the main factors contributing to being HIV tested, as well as frequency of testing. The positive influence of emotional support on these variables was borderline significant. CONCLUSION: People who use non-injected drugs are less likely to test for HIV compared to those who use injected drugs, though they may share similar risk factors for HIV transmission and acquisition. To exert a greater impact on the HIV epidemic, interventions and policies encouraging HIV testing in this subpopulation, which remains under-recognized by both researchers and health practitioners in terms of the potential risks for contracting the HIV, are warranted.
183

Patient non-retention, loss to follow-up and death after ART initiation at HIV care and treatment facilities in sub-Saharan Africa: the influence of adherence support and outreach services

Lamb, Matthew Raymond January 2011 (has links)
This dissertation uses three types of routinely collected data from HIV care and treatment facilities in sub-Saharan Africa to investigate the association between the availability of adherence support and active outreach services on patient non-retention, loss to follow-up, and measured death after ART initiation. Following a literature review summarizing the state of knowledge concerning the influence of programmatic services on patient retention in care and survival, these relationships are first examined in an aggregate analysis of over 232,000 patients at 349 HIV care and treatment facilities initiating ART between January 2004 and December 2008. Key findings are that several adherence support and outreach services are associated with reduced rates of non-retention, loss to follow-up, and death. Specifically, facilities offering three or more adherence support services, written educational materials promoting ART adherence, one-on-one or group adherence counseling sessions, reminder tools, and food rations to promote ART adherence were associated with reduced non-retention and loss to follow-up, while facilities offering on-site support groups for HIV+ patients, peer educators, provision of reminder tools, and food rations to promote ART adherence were associated with reduced death rates. In sub-analyses investigating six- and 12-month retention after ART initiation, facilities offering three or more separate adherence support services, routine review of medication pickup and/or dedicated ART pharmacists, and active patient outreach to trace patients missing visits had lower non-retention. Taken together, this analysis provides evidence that program-level services found efficacious in experimental settings are also effective in operational settings. Next, a sub-analysis is conducted among facilities also providing electronic patient-level data to investigate similarities and differences in the association between adherence support and outreach services and patient non-retention, loss to follow-up, and measured death using aggregate vs. patient-level estimates of these outcomes, and to assess whether adjustment for patient-level differences between facilities change these measures of association. In multivariate analyses, clinics offering active patient outreach had lower rates of non-retention in both the ART cohort analysis and the patient-level analysis, and clinics offering food rations to promote ART adherence were associated with a lower risk of ascertained death in both the facility-level and patient-level analyses, but this association was diminished after adjustment for patient-level covariates. In contrast, various adherence counseling or support services were associated with lower non-retention in the ART cohort analyses but not in the patient-level data analyses. When compared with the results in the first paper, fewer associations were observed, suggesting either that the countries with patient-level databases are not representative of the entire range of HIV care and treatment facilities assessed in the first paper, and/or the specific facilities with electronic databases are more similar to each other than they are to facilities without electronic databases. Finally, the dissertation concludes with an investigation into the relationship between loss to follow-up and measured death. For this analysis, estimates of the death probability among patients lost to follow-up are created under varying assumptions (either assuming that the death probability among those lost to follow-up is equivalent to the death probability within various strata of covariates, or assuming that the probability of death is greater among patients lost to follow-up). Key findings from this analysis are that ratio comparisons of death rates between facilities offering different services are robust to changes in the death probability if patients lost to follow-up are assumed to have a similar probability of death, conditioned on covariates, as those not lost to follow-up, but that associations between facility services and death rates are masked under the scenario where the facility service is associated with loss to follow-up and the death probability is assumed to be higher, conditioned on covariates, then the death probability among patients not lost to follow-up.
184

The Effects of Antiretroviral Therapy Scale-Up on Tuberculosis and Non-Communicable Diseases Health Service Utilization and Mortality Risk among the General Population in Rural South Africa, 2009-2014

Saito, Suzue January 2018 (has links)
The overall purpose of this dissertation was to examine evidence of spillover effects of HIV care and treatment service scale up in sub-Saharan Africa in the past decade. Particularly the focus was to quantify any effect HIV treatment initiation by a person living with HIV (PLHIV) may confer health benefits to the HIV negative population by increasing utilization of non-HIV services or reduce mortality risk. This dissertation had three primary aims. The first aim was to conduct a systematic review of the effect of increasing ART uptake in high HIV prevalence communities on use of non-HIV health services, including maternal, child, in/out-patient, non-HIV laboratory, and TB diagnosis and treatment services. Overall positive effects were found on the majority of health service indicators examined for non-HIV laboratory service utilization and Tuberculosis diagnosis and treatment services. We found negative associations on the majority of indicators examined for child health services. The existing evidence did not point to clear tendencies for maternal health services and outpatient and inpatient services. Restricting the sample to studies with stronger study designs for causal inference, the positive effect on non-HIV laboratory services and the negative impact on child health services held but evidence was mixed for TB diagnosis and treatment services, maternal health services and outpatient and inpatient services. The second aim of this dissertation was to conduct regression discontinuity quasi-experiments to determine whether exposure to health benefits from ART utilization by a person living with HIV (PLHIV) in a household affects uptake of TB, hypertension (HTN) and diabetes mellitus (DM) treatment by other household members with these conditions. The study was conducted in the comprehensive population cohort followed by the Africa Health Research Institute (AHRI) in Kwazulu-Natal (KZN), South Africa. We linked PLHIV engaged in HIV care to their cohabitating household members aged ≥15 years using a unique identifier for homesteads. Household ART utilization significantly increased treatment for diabetes (RR 1.90: 95% CI 1.07-3.40) but not for TB (RR 1.12: 95% CI 0.71-2.03) or hypertension (RR 1.31: 95% CI 0.97-1.77). The third aim of this dissertation was to use the same regression discontinuity design and KZN cohort data as in aim 2 to determine whether exposure to health benefits from ART utilization by PLHIV in a household reduces all-cause mortality of other household members. Overall, household ART utilization did not decrease all-cause mortality (Hazard Ratio (HR) 0.95: 95% CI 0.65-1.4), however, restricting the analysis to a narrow CD4+ cell count range around the regression discontinuity threshold showed reduced all-cause mortality by 67% (HR 0.43: 95% CI 0.22-0.85) among household members of PLHIV on ART; the reduced risk was driven largely by the significant reduction noted among female household members (HR 0.21: 95% 0.08, 0.56).
185

HIV related risk behaviours in South African rural community

Nemuramba, Rathani January 2010 (has links)
Thesis (M.A. (Research Psychology)) --University of Limpopo, 2010 / This study measures the relationship between the AIDS risk reduction model (ARRM) variables associated with HIV related risk behaviours on learners from a South African rural community. A cross-sectional study was conducted using 308 learners in a Limpopo rural high school to identify HIV risk behaviours. Data were analyzed using binary logistic regression to test the usefulness of ARRM variables in predicting sexual risk. Sexual risk was measured as; (a) vaginal sex without a condom, (b) anal sex without a condom (c) number of sexual partners in the last twelve months and (d) time taken before having sex with a new partner. Two of the ARRM variables, that is perceived susceptibility and sexual response efficacy, were found to be the most important predictors of HIV related risk behaviours. There is an argent need for effective preventive activities in rural areas, especially through school-based interventions. Key words: ARRM HIV HIV prevention Risk behaviors
186

Refugees' perception of HIV and AIDS in Ba-Phalaborwa municipality, Limpopo Province

Nkwinika, Hlekani Elizabeth January 2006 (has links)
Thesis (M.Dev.) --University of Limpopo, 2006 / The research aimed at exploring and describing the perceptions of the refugees at Humulani village in the Ba-Phalaborwa municipality about HIV and AIDS. The objectives including determining the gender perceptions about HIV and AIDS and also providing recommendations for ways to increase the refugees’ understanding of HIV and AIDS. The approach used for the research was a quantitative approach. The target population of the study was all the refugees at Humulani village. The sample was comprised of both males (78) and females (122) who participated by completing questionnaires. The sample of the refugees consisted of different ethnic groups from Mozambique, Nigeria, Ghana and Zimbabwe. The questionnaires consisted of three sections, section A, B and C. The findings of the study revealed that the participants had low levels of knowledge regarding HIV and AIDS which could be attributed to their possession of false myths about HIV and AIDS. The outline of the dissertation was as follows: Chapter 1 introduced the study and discussed the research problems, aim of the study, objectives of the study, research question, significance of the study, motivation of the study and definition of concepts. Chapter 2 discussed the literature review conducted on the refugees’ perceptions of HIV and AIDS. Chapters 3 discussed the research methodology of the study and describe the research design population, sample, data -collection instrument, limitation of the study and ethical considerations adhered to during and after collecting data. Chapter 4 discussed the data analysis and interpretation with reference to literature review.In chapter 5 the evaluation of the study, objectives, conclusions, recommendations and suggestions for further research were presented. Based on the findings it was recommended that the health Profession’s awareness campaigns should be strengthened and designed to reach refugees by taking into account the cultural contexts of the refugees
187

How do education and information affect health decisions? : the cases of HIV/AIDS and smoking /

De Walque, Damien. January 2003 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Economics, August 2003. / Includes bibliographical references. Also available on the Internet.
188

Gender relations, sexuality and HIV/AIDS education : a study of Ghanaian youth cultures

Oduro, Georgina Yaa January 2010 (has links)
No description available.
189

Partnership in whose interests? : the impact of partnership-working in a Cambodian HIV prevention program

Aveling, Emma-Louise January 2010 (has links)
No description available.
190

The prevalence of human immundeficiency seroposivity in patients presenting with first episode psychosis.

Mashaphu, Sibongile. January 2007 (has links)
Background Patients infected with the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome (AIDS), have high rates of psychiatric morbidity. The effects of HIV on the Central Nervous System may lead to psychiatric morbidity even before the appearance of the full-blown AIDS syndrome. Sero-prevalence studies of patients with psychoses have found an estimated 5-20% to be HIV positive. However, sero-prevalence estimates vary from study to study due to the differences in sampling by geographic location, socio-economic class, race and ethnicity, and psychiatric-diagnostic composition. The Republic of South Africa has some of the highest prevalence rates in the world and research in this field is escalating rapidly. However research on HIV in patients with mental illness, particularly psychosis is very sparse. Aim of the study To determine the prevalence of HIV sero-positivity amongst patients admitted to Town Hill hospital presenting with first episode psychosis. Method All patients presenting to Town Hill hospital with first episode of psychotic symptoms were recruited to participate in the study. The treating doctor in collaboration with the multi-disciplinary team made the diagnosis of Psychosis. A total number of 63 patients participated in the study. Results. 23.8% of the patients tested positive for the human immunodeficiency virus. Conclusions. The prevalence of HIV sero-positivity is high amongst patients presenting with first episode psychosis. The HIV epidemic could have an important effect on the aetiology and clinical presentation of psychosis. Recommendations State mental health authorities should pursue the promotion of voluntary HIV testing programs, in patients presenting with first episode psychosis as soon as they are capable of giving informed consent. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2007.

Page generated in 0.0267 seconds