1,721,078 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Prevalence of asymptomatic sexually transmitted infections: a retrospective review of screening data from Desmond Tutu HIV Centre clinical trial cohorts from 2012 to 2017, Cape Town
Full text linkBackground: The burden of Sexually transmitted infections (STIs) is high globally. The World Health Organisation (WHO) recommends syndromic management of these STIs, based on presentation with signs and symptoms, in resource-limited countries. Due to this syndromic approach, there is little current data on STI prevalence, including asymptomatic STIs, in high risk populations. Methods: We reviewed secondary data collected as part of the screening procedures of 6 clinical trials between 2012 and 2017 in Cape Town, South Africa. These trials recruited populations of different sexual orientation and gender, mostly key populations at risk of HIV and STI acquisition. Routine screening for STI symptoms and testing for Chlamydia, Gonorrhoea, Trichomonas, Syphilis and HIV was performed for all of the studies at screening/enrollment. Results: A total of 639 participants were screened; 411 (64.3%) self-identifying as female, 198 (31%) males, 29 (4.5%) transgender women and 01 (0.2%) transvestite. Median age was 20 years (IQR: 18-24), with the 15-24-year age category contributing 77% to the cohort. Laboratory testing diagnosed 239 (37.4%) people with STI infections in this cohort; only 28 (11.7%) people were symptomatic. 119 (88.8%) of Chlamydial, 64 (82.1%) of Gonorrhoeal, 23 (92%) of Trichomonal and 31(79.5%) of Syphilis infections elicited no signs and/or symptoms. Conclusion: A vast majority of STIs in this high-risk population were asymptomatic. Laboratory testing of causal organism was more reliable in diagnosing STIs than the use of signs and/or symptoms as recommended by WHO
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The impact of stressful life events on antiretroviral treatment adherence and viral load amongst adults in Gugulethu, Cape Town
Full text linkOptimal antiretroviral treatment (ART) adherence is critical in achieving virologic suppression. Most people living with HIV (PLWH) experience HIV-related challenges which may be compounded by the experience of stressful life events (SLE) with adverse effects on their ART adherence and therefore affecting viral suppression. The highest concentration of people living with HIV (PLWH) is in low-and-middle income countries (LMIC) which are challenged with high rates of poverty and unemployment. Limited published data is available on the impact of the stressful life events experienced by PLWH in LMIC on ART adherence and viral load. A secondary analysis was conducted using data collected in a randomised control trial (RCT) which investigated the impact of a real-time electronic adherence monitoring device (EAMD) on ART adherence in ART-naïve individuals to assess the impact of SLE on ART adherence and viral load. Part A of this dissertation includes the study proposal/ protocol as approved by the Departmental Research Committee and the Human Research Committee at the University of Cape Town. Part B details the literature review which examined all published studies which report on stressful life events in PLWH, with ART adherence or a viral load as an outcome. The review included published literature from 2008 to 2019. Part C includes the publish-ready manuscript which details the statistical analysis, results and interpretation of the secondary analysis of impact of SLEs on ART adherence and viral load among 200 individuals living with HIV. Part D, appendices were included as supporting documentation necessary for the conduct of this research and as required for the completion of this dissertation. The American Psychological Association (APA) 6th Edition referencing style was used for Part A and B. The Vancouver referencing style was used for Part C as per the instructions for authors by the Aids and Behaviour journal guidelines
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Understanding women's engagement in HIV care after initiating antiretroviral therapy during pregnancy in South Africa
Full text linkBackground: Sustained engagement in HIV care, including adherence to antiretroviral therapy (ART) and retention in HIV services, is essential to optimize maternal health and prevent perinatal, postnatal and sexual HIV transmission. However, engagement in care remains a substantial challenge for pregnant and postpartum women. Women’s experience of and response to barriers to engagement in care, including ART side effects, transfer of care and mobility, may be altered by the transitions experienced in pregnancy and motherhood, and there have been few quantitative analyses of these risk factors in maternal ART cohorts. The way engagement in HIV care is measured also varies widely and no gold standard measures of ART adherence or retention exist. Composite assessments of adherence and retention, including drug concentrations, longitudinal self-reported adherence, and interlinked routine electronic health data, have not been thoroughly evaluated among African women living with HIV. To address these gaps in knowledge, this thesis investigates novel measures of ART adherence, and evaluates interlinked routine electronic health data to measure retention in a South African maternal ART cohort. It describes maternal engagement in HIV care, and examines barriers to engagement that require consideration specific to maternal ART. Methods: This research included women who initiated ART during pregnancy in a large integrated antenatal care and ART clinic in Gugulethu, South Africa (2013-2014). Until July 2013, only women who met certain clinical criteria (CD4 cell count 0.850) compared to self-reported adherence using a cross-sectional three-item scale (0.756). Longitudinal measurement of the same self-reported adherence scale showed that reporting worse adherence on any of three items over consecutive visits could predict viremia (>50 and >1000 copies/mL), particularly among women who were suppressed at the initial visit. Measuring retention using routine interlinked electronic data facilitated tracing of women beyond transfer from the integrated clinic to any clinic where they accessed HIV care postpartum. Estimates of retention varied widely using different retention definitions and data sources. Overall, electronic primary health care data, linked across clinics, performed better than laboratory data alone and was a robust measure for monitoring retention in HIV care. Conclusions: Taken together, these findings underscore a concerning level of disengagement from HIV care during and after pregnancy. Potential ART side effects, required transfer of care, the potential challenges of mobility and the importance of sustained engagement in care beyond pregnancy and breastfeeding, should be emphasised in ART counselling. Drug concentrations in DBS and plasma strongly predict viral suppression, but these data on longitudinal self-reported adherence provide a proof of concept for a low resource interim adherence measure that warrants further investigation in routine care settings with limited resources for viral load or drug concentration testing. Transfer of care and postpartum mobility mean that interlinked data sources are essential to obtain accurate estimates of retention postpartum. Further evaluation of the optimal approaches to transferring maternal ART care and the development of interventions to support engagement both in and beyond the clinic of ART initiation will be critical to sustain maternal engagement in HIV care in the long term
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Longitudinal latent class and joint modelling of antiretroviral adherence
Full text linkThis dissertation investigates the relationship between antiretroviral therapy (ART) adherence and viral outcomes in people living with HIV in South Africa using advanced statistical modeling techniques. Utilizing data from the ADD-ART study, a prospective cohort of 238 adults on ART in Cape Town, the research employs survival analysis, joint modeling, and longitudinal latent class analysis to compare di↵erent adherence monitoring tools and examine heterogeneity in adherence behaviors. Key findings include: Electronic Adherence Monitoring (EAM) and tenofovir diphosphate levels in dried blood spots were more strongly associated with viral non-suppression than self-reported adherence; joint modeling revealed a stronger association between EAM adherence and viral outcomes compared to traditional survival models, with each additional missed dose in the preceding 30 days associated with an 81% increase in the hazard of viral non-suppression; longitudinal latent class analysis identified five distinct adherence trajectory groups, with poorer or declining adherence groups experiencing significantly higher rates of viral non-suppression; baseline viral load and prior tuberculosis exposure were significant predictors of subsequent viral non-suppression, even after accounting for adherence. The results highlight the importance of using objective adherence measures, the value of advanced statistical techniques in HIV research, and the need for personalized adherence support strategies. Limitations include potential violations of model assumptions and generalizability constraints
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