1,720,954 research outputs found
Mathematical and statistical modelling of Sexually Transmitted Infections and their impacts on fertility
Get PDFUniversity of Technology Sydney. Faculty of Science.Adverse reproductive health outcomes, such as pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility, have been associated with Chlamydia trachomatis and Neisseria gonorrhoea infections. These reproductive health outcomes could be complemented by measuring subsequent pregnancies assessing impact on fertility.
In this thesis, a number of statistical and mathematical modelling approaches were developed and utilised. Throughout the results, the value of using multiple modelling techniques in a single scientific domain is demonstrated by elucidating the reproductive burden of Chlamydia Trachomatis and the host and pathogen factors that moderate this.
Using a retrospective data linkage cohort study of 132,962 women based in QLD, we found that women with a history of testing for Chlamydia and/or Gonorrhoea had reduced odds of pregnancy, depending on the age of the women at testing and any prior occurrences of pregnancy (aOR 0.91, 95% CI 0.87 - 0.95 for women aged 20 with no prior pregnancy compared to no history of testing, aOR 0.71, 95% CI 0.68 - 0.75 for women aged 25, aOR 0.87, 95% CI 0.79 - 0.95 for women aged 30). After adjusting for Indigenous status, using a multiple imputation process to account for cases where women identified differently in different data sources, we found that non-Indigenous women with multiple positive tests were significantly less likely to be pregnant than women with all negative tests, whilst there was a small reduction in pregnancy odds following a single positive test (aOR 0.66, 95% CI 0.44 - 0.99; aOR 0.93, 95% CI 0.83 - 1.04 respectively). The same results were not replicated for Indigenous women (aOR 0.92, 95% CI 0.53 - 1.60, aOR 1.34, 95% CI 1.08 - 1.65 for multiple positive and single positive tests respectively), suggesting a set of demographic and biological factors moderated these results.
The progression to pathology is thought to be governed by ascension of Chlamydia Trachomatis to the upper genital tract. We developed a mathematical model based on a set of stochastic dynamics to investigate the moderating impacts of ascension. We found that ascension was dependent on the neutrophil response, and that the interplay between the neutrophil response, menstrual cycle timing and initial infectious load were critical factors in moderating ascension. The distribution of the number of bacteria ascending had a long right-tail (of all simulations, 36% showed bacteria ascending, but only 9% showed 1000 or more bacteria ascending, and 0.1% showed more than 10,000 bacteria ascending)
Stochastic modelling of chlamydial infections
Get PDFChlamydia trachomatis is a bacterial pathogen that can cause serious reproductive harm. We describe a class of stochastic branching processes and their application in modelling the growth of an infection by Chlamydia. Using simulations we show that the model can reproduce biological phenomena of interest, and we show the variability in outcomes of infections under the same parameter conditions. We further speculate how this model might be used to explain long-term adverse reproductive sequelae.
References
Y. M. AbdelRahman and R. J. Belland. The chlamydial developmental cycle. FEMS Microbio. Rev., 29(5):949–959, 2005. doi:10.1016/j.femsre.2005.03.002.
T. E. Harris. Branching processes. Ann. Math. Stat., 19(4):474–494, 12 1948. doi:10.1214/aoms/1177730146.
C. Jacob. Branching processes: Their role in epidemiology. Int. J. Env. Res. Public Health, 7(3):1186–1204, 2019. doi:10.3390/ijerph7031204.
N. Low, M. Egger, J. A. C. Sterne, R. M. Harbord, F. Ibrahim, B. Lindblom, and B. Herrmann. Incidence of severe reproductive tract complications associated with diagnosed genital chlamydial infection: The Uppsala women's cohort study. Sexually Trans. Infect., 82(3):212–218, 2006. doi:10.1136/sti.2005.017186.
D. Mallet, M. Bagher-Oskouei, A. Farr, D. Simpson, and K. Sutton. A mathematical model of chlamydial infection incorporating movement of chlamydial particles. Bull. Math. Bio., 75:2257–2270, 10 2013. doi:10.1007/s11538-013-9891-9.
H. K. Maxion, W. Liu, M.-H. Chang, and K. A. Kelly. The infecting dose of chlamydia muridarum modulates the innate immune response and ascending infection. Infect. Immun., 72(11):6330–6340, 2004. doi:10.1128/IAI.72.11.6330-6340.2004.
S. Menon, P. Timms, J. A. Allan, K. Alexander, L. Rombauts, P. Horner, M. Keltz, J. Hocking, and W. M. Huston. Human and pathogen factors associated with chlamydia trachomatis-related infertility in women. Clinic. Microbio. Rev., 28(4):969–985, 2015. doi:10.1128/CMR.00035-15.
D. P. Wilson. Mathematical modelling of chlamydia. In J. Crawford and A. J. Roberts, editors, Proc. of 11th Computational Techniques and Applications Conference CTAC-2003, ANZIAM J., volume 45, pages C201–C214, 2004. doi:10.21914/anziamj.v45i0.883.
D. P. Wilson and D. L. S. McElwain. A model of neutralization of chlamydia trachomatis based on antibody and host cell aggregation on the elementary body surface. J. Theor. Bio., 226(3):321–330, 2004. doi:10.1016/j.jtbi.2003.09.010.
D. P. Wilson, P. Timms, and D. L. S. McElwain. A mathematical model for the investigation of the Th1 immune response to chlamydia trachomatis. Math. Biosci., 182(1):27–44, 2003. doi:10.1016/S0025-5564(02)00180-3
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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