1,720,992 research outputs found
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
Molekularphylogenetische Analysen der Ecdysozoa und Haemosporida
No full textThe advent of molecular phylogenetics has revolutionized our understanding of the tree of life. In my PhD thesis, I have aimed to elucidate various aspects of the deep phylogeny of Ecdysozoa and Haemosporida employing classical PCR-based approaches, next-generation sequencing, and bioinformatic data mining techniques.
The superphylum Ecdysozoa was first proposed based on phylogenetic analyses of 18S rRNA sequences. Among others, it comprises the two most species-rich animal phyla, Arthropoda and Nematoda. The Ecdysozoa concept was initially received with considerable skepticism and controversy as it contradicted traditional animal systematics; and while it is now widely accepted in the scientific community, the relationships within Ecdysozoa have remained poorly understood. To improve our understanding of the deep phylogeny of Ecdysozoa, new transcriptome data from a number of ecdysozoan species belonging to previously undersampled taxa were generated. All phylogenetic analyses found strong support for the monophyly of Ecdysozoa. The scalidophoran taxa Priapulida and Kinorhyncha were recovered in a sister group relationship at the base of Ecdysozoa. Within Euarthropoda, I found strong support for a common origin of Myriapoda, Crustacea, and Hexapoda (Mandibulata hypothesis) thus rejecting the notion of a sister group relationship between Myriapoda and Chelicerata (Myriochelata hypothesis), which was recovered in a number of earlier molecular analyses. Molecular clock analyses resulted in divergence time estimates that are notably younger than the estimates of most previous studies based on sequence data. However, the molecular dates still significantly predate the earliest fossil evidence and point to an Ediacaran origin of Arthropoda followed by diversification of the extant arthropod subphyla in the Cambrian.
Haemosporida are intracellular blood parasites with a complex life cycle that infect a great variety of vertebrate hosts. Haemosporidians are member of the phylum Apicomplexa and include the agents of human malaria (genus Plasmodium). Despite being the focus of numerous studies, there is still no consensus on the deep phylogeny of Haemosporida. As genome sequencing projects have focused on mammalian parasites of the genus Plasmodium, sequence data from the other haemosporidian genera was only available for a small set of standard genes, which are not ideal for reconstructing the earliest events in haemosporidian evolution. This limited gene sampling is due to numerous challenges involved in developing nuclear markers for this diverse group. By employing a newly developed bioinformatic pipeline for primer design and by carefully optimizing design parameters and PCR protocols, I was able to obtain sequence data from a number of nuclear genes in haemosporidian species belonging to the genera Haemoproteus, Leucocytozoon, Polychromophilus, and Plasmodium. Phylogenetic analyses resulted in highly congruent topologies consistently placing Leucocytozoon at the base of Haemosporida. Surprisingly, the phylogenetic analyses recovered Polychromophilus, a genus of bat-infecting parasites, as the sister group to a monophyletic clade comprising all Plasmodium parasites. This relationship has not been proposed before but is well supported and appears plausible when considering various aspects of parasite life history. Within Plasmodium, a sister group relationship between the avian and the mammalian species was found.
Contamination by DNA from external sources (e.g. cloning vectors or human DNA) is a common problem in NGS projects. If the contaminating sequences are not identified and remain in the datasets after sequence assembly and deposition into public databases, subsequent analyses may yield confusing results that can lead to false conclusions. Moreover, the identification of parasite-derived contaminations may also enable the discovery of novel parasite lineages and shed light on previously unknown host-parasite associations. In order to quantify the extent of contamination by apicomplexan parasites in the public genome and transcriptome databases and to extract as many parasite-derived contigs from the contaminated animal assemblies, I developed a software pipeline that uses a series of sequence similarity searches to identify contigs of parasite origin. In total, 953 assemblies of terrestrial animals were analysed and, in 51 assemblies, a combined 20,907 contigs from apicomplexan parasites were found. For most of the contaminating parasite species, no molecular data had been available previously and, for some of them, large amounts of the parasite's gene repertoire could be extracted from the sequence assemblies. Phylogenetic inference yielded a well-resolved tree and the contaminating parasite species could be identified as members of the apicomplexan taxa Gregarinasina, Coccidia, Piroplasmida, and Haemosporida
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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