1,721,036 research outputs found
Nikolas Pontikos PhD Thesis 2015
No full text<p>PhD thesis (submitted July 2015).</p>
<p>Genetic association studies have discovered many variants which influence type 1 diabetes (T1D) risk and further correlate with quantitative cell-type specific phenotypes. However, disease associated differences can be small, and large numbers of samples are required to overcome the heterogeneity that exists between humans.<br>Novel high-throughput biotechnologies measure large number of samples but technical or within-batch variation, may undermine reproducibility of measurements.</p>
<p>In my thesis, I analyse two types of these datasets, central to the study of T1D. The first is generated by flow cytometry, a biotechnology utilising light scatter and fluorescently stained markers to discriminate different cell types. Unfortunately, flow cytometry can be prone to batch effects since blood samples are often collected, prepared and analysed at different times and by different operators. I consider several normalisation techniques to address these issues, using external or within sample controls. The main objective of flow cytometry data analysis is that of identifying different cell types. While this is essentially a clustering problem, currently the most widely applied method is a manual approach which can be inefficient and biased. I investigate ways this process can be automated by fitting mixture models to emulate the manual process. I show that, in the absence of manual gates, data-driven approaches can be applied to detect new cell subsets, not targeted by manual gating, that respond to IL-2 in an in-vitro stimulation experiment.</p>
<p>The second type of dataset is generated by qPCR and genotyping arrays, which are applied to DNA from T1D cases and controls to determine whether copy number variation in two Killer Immunoglobulin-like Receptors (KIRs) genes associates with T1D.<br>I apply normalisation to correct for batch effects between qPCR plates and clustering using mixture models to identify copy number groups.<br>Supervised clustering is then used to correlate qPCR copy number with SNP data, allowing for association testing in a twenty-fold larger sample size than ever previously considered for KIR genes.</p>
<p>Finally, I conclude with what I have learned from applying these methods and how these may be further developed, with special attention to flow cytometry where these remain under utilised. In particular, I discuss how normalisation and clustering relate, and how prior knowledge, when available, can be incorporated into the clustering process.</p>
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Integrating exome and whole genome analysis with the Human Phenotype Ontology for discovery of new genes in rare eye diseases
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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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