1,720,956 research outputs found
Factors and mechanisms contributing to the regulation of the developmental cycle in Chlamydia trachomatis
No full textChlamydia is an obligate intracellular bacterium causing one of the most commonly reported bacterial sexually transmitted infections in humans. It is asymptomatic in nature and exposure to infants can lead to neonatal blindness. Despite such serious consequences and high stakes, there are restricted treatment options and no available vaccines. Developing therapeutics has been challenging with chlamydia because it has been difficult to manipulate the organism and hence there is a paucity of available information about the basic biology of the organism. This is further complicated by 30% of the chlamydial genome being unannotated and defined as hypothetical protein coding genes.This dissertation attempts to bridge the gap of knowledge about chlamydial biology by using two different methods- 1) Through genetic studies by transposon mutagenesis and inter-species recombination in Chlamydia and 2) Through structure-function studies to characterize the role of 2 hypothetical proteins in Chlamydia trachomatis.The first aspect of the document emphasizes on how different kinds of unbiased genetic approaches can help us delve into the roles of gene products in chlamydial growth and infection capabilities. The genetic studies from transposon mutagenesis in Chlamydia trachomatis demonstrated the role of several chlamydial proteins in the developmental cycle of Chlamydia trachomatis by characterizing select mutants. Mutants obtained in this study can be individually characterized and insights to the regulation and role of different genes during the progression of the developmental cycle can be gathered. The second part of the genetic study concentrated on understanding the species-specific role of genes to understand the pathogenesis. In the context of this dissertation, once the chimeras were obtained around the region of differences between Chlamydia trachomatis and Chlamydia muridarum- called the Plasticity Zone (PZ), the growth phenotypes were assessed. These chimeras had the Chlamydia muridarum plasticity zone in a Chlamydia trachomatis background. Results support that the genes in the PZ region contribute to the growth and inclusion size expansion irrespective of the species but the genes that are directly contributing to these factors are part of the full PZ and the right partial PZ. The chimeras majorly had Chlamydia trachomatis-like growth and further validation of the genes crossed over in these recombinants is warranted.The second and major aspect of this dissertation focuses on understanding gene regulation and the role of hypothetical proteins in gene regulation during the developmental cycle of Chlamydia trachomatis. Here we attempted to characterize two hypothetical proteins- CT398 (CdsZ) and CT457 (YebC). These proteins had little sequence similarity with other bacteria but had no identified role in Chlamydia trachomatis. The protein structures of these proteins were crystalized, and the function was assessed using structural homology and in vivo over-expression of the protein approaches. Our data support that CdsZ over-expression had a profound impact on chlamydial RB to EB reorganization. RNA seq results showed down-regulation of a subset of late genes. Moreover, this regulation of conversion was mediated in a temporal fashion and most likely through the CdsZ interacting with RNA polymerase machinery during transcription. The data also suggests its regulatory role based on interaction with the Type III secretion system and its effect on pathogenesis. Further validation is needed to understand this mechanism. The last chapter focuses on the regulatory role of CT457 (YebC) during the developmental cycle. Although, we have transcriptional and translational data to show that it is constitutively present through the developmental cycle, over-expression had no effect on chlamydial growth or gene expression. Further optimization of assays is needed to decipher the exact role of CT457 given that it is a conserved protein and it could have the same role in different species of Chlamydia
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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