1,720,957 research outputs found
Genomic variation and gene expression of clinical isolates of Mycobacterium tuberculosis.
Full text linkMembers of the Mycobacterium tuberculosis complex, M. tuberculosis, M. bovis, M. microti, M. canettii and M. africanum, share over 99.9% identity at the DNA level. However, several recent studies have shown that there is considerably more genomic variation within the species when the organisation of the entire genome is considered, rather than primary sequences of individual genes. Therefore, to uncover the genomic variation within the species, one of the aims of this project was to compare the genome of several strains of M. tuberculosis, M. africanum, M. bovis (human and cattle isolates) and M. bovis BCG (Pasteur) using the M. tuberculosis H37Rv DNA microarray. The Beijing family of strains within the M. tuberculosis complex has been frequently associated with outbreaks of tuberculosis. Furthermore, several recent studies have shown that there are considerable selective advantages of the Beijing strains such as multidrug-resistance, higher adaptability to exposure to antituberculosis drugs and more infectivity in patients in countries such as China and Russia. The aim of this project was to understand the molecular basis for differences in virulence and infectivity amongst M. tuberculosis Beijing strains. The specific aims of the project were: (i) To investigate gene expression in response to stress conditions in the Beijing 94-1576 and Beijing 94-1707 strains. (ii) To investigate in vivo phenotypes of the Beijing 94-1576 and Beijing 94- 1707 strains. Comparative genomics was used to identify deletions of the RD1-RD14 regions as defined in M. bovis BCG. Regions of difference (RD) were used to reveal an evolutionary pathway for members of the M. tuberculosis complex and from this study, the presence of RD9 in one of the M. bovis isolated from cattle revealed a divergence from the published evolutionary pathway. It was anticipated that the selection of the M. tuberculosis strains from different sources might help uncover associations between genotype and host specificity in addition to exploring the scope of genotypic diversity. The M. tuberculosis isolates from India and different geographical areas such as Tanzania, Vietnam and Argentina did show a wide variation in the number, size and distribution of deletions. The Beijing strains showed a specific pattern of genomic variability with each having four large deletions compared to H37Rv. The genotypic characteristics of the Beijing family are (i) absence of the TbDl region, (ii) polymorphisms in the Rv3135 gene, the a/G463CTG (Leu) and gyrA95ACC (Thr) alleles and (iii) transposase insertion in the dnaA-dnaN and NTF-1 regions. In this study, the Beijing genotyping was performed and did confirm that the 94-1576 and 94-1707 strains were Beijing strains. The DNA microarray technique is only informative in detecting deletions that are present in the test strains compared with the reference strain H37Rv. To overcome this limitation, the subtractive hybridisation technique was applied and was able to identify a diverse polyketide synthase gene in the Beijing 94-1576 and Beijing 94-1707 strains. A study on gene expression in response to environmental stress conditions was performed to understand the influence of genome differences on gene regulation in H37Rv, Beijing 94-1576 and Beijing 94-1707. Using this, it proved possible to identify a number of significant differentially expressed genes involved (i) in oxidative and low pH stress for H37Rv, (ii) in oxidative and low pH stress for Beijing 94-1576, (iii) low pH and nitrosative stress for Beijing 94-1707. Finally, a number of experiments were done to investigate phenotypic differences between H37Rv, Beijing 94-1576 and Beijing 94-1707. This was done with a view to understand why the Beijing strains have become so successful in spreading across the world. In the initial stage of growth in the Balb/C mice, H37Rv, Beijing 94-1576 and Beijing 94-1707 grew progressively until day 28 before differences were seen between the strains. Infection in the human monocytic cell line THP-1 showed that the mycobacterial load of both Beijing 94-1576 and Beijing 94-1707 was higher than H37Rv. However, in C57BL/6 mice and murine bone marrow derived macrophages, the mycobacterial load of Beijing 94-1707 was significantly lower than H37Rv and Beijing 94-1576
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
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
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
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
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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