1,720,954 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
Untangling spatial, environmental, and genetic drivers of foliar endophyte community assembly
No full textUniversity of Minnesota Ph.D. dissertation. October 2025. Major: Ecology, Evolution and Behavior. Advisor: David Moeller. 1 computer file (PDF); xi, 118 pages.Plants and their microbiomes form integrated systems where the boundaries between host and microbe are often blurred. Foliar fungal endophytes—fungi living asymptomatically inside healthy leaves—colonize virtually all terrestrial plants and can profoundly influence host performance through effects on stress tolerance, pathogen resistance, and resource acquisition. Despite their ubiquity and ecological importance, we lack fundamental understanding of what determines which fungi colonize which plants. The central challenge is that multiple processes simultaneously shape communities—dispersal moves microbes across landscapes, environmental conditions filter which taxa can persist, and host plants selectively permit or exclude colonizers based on their traits—but these processes operate at different spatial scales and interact in complex ways that are rarely studied together, particularly in natural field environments.
Understanding microbial community assembly requires disentangling processes that operate hierarchically across biological scales. Regional dispersal patterns determine which taxa are present in a landscape, local environmental conditions filter this regional species pool, and host plants impose a final filter through their genetic makeup and expressed traits. However, testing this framework is challenging because spatial and environmental variation are often confounded, environmental conditions can alter host trait expression, and the specific plant traits mediating host genetic effects remain largely mysterious. While agricultural systems have provided valuable mechanistic insights, wild plant populations remain critically understudied, particularly through experimental approaches that can establish causation rather than correlation. I address these challenges through a novel ecological genetics approach that combines observational surveys with experimental manipulations of host origin and genotype in wild populations. Working with Clarkia xantiana, a wild annual wildflower native to California's Sierra Nevada foothills, I progressively narrow spatial scale while increasing experimental control.
In Chapter I, I surveyed endophyte communities across 50 sites spanning 100 kilometers to quantify how community structure is associated with geographic distance, environmental factors, and host identity. I separated out these often-confounded factors by repeatedly co-sampling three herbaceous plant species across a topographically complex landscape where space and environment are largely decoupled. Our study reveals that community composition shows strong associations with spatial distance, while alpha diversity varies in relation to environmental gradients differently across host species. Within sites, host species harbor largely distinct communities, yet the specific taxa associated with each host vary inconsistently across locations. This chapter establishes that different assembly processes may affect different axes of community variation and that the strength of host associations is scale-dependent.
In Chapter II, I implement a fully reciprocal transplant experiment across four sites, growing plants from four genetically differentiated source populations at all four sites in a factorial design. Despite clear fitness variation among populations, I find that site effects overwhelm source population influences on endophyte communities. Local environmental filtering and the available microbial species pool appear far more important than host population genetics, even though populations differ in traits potentially relevant to microbe interactions. This reveals that while host species identity matters, naturally occurring intraspecific genetic variation has minimal detectable effects under realistic field conditions.
In Chapter III, I take an experimental ecological genetic approach, manipulating host genotype within a single site using recombinant inbred lines that segregate for leaf anthocyanin content. By creating genetic variation in this target trait that exceeds what is found in natural populations, I test mechanistic hypotheses about trait-mediated assembly. Growing 48 genetic lines under factorial water and fungicide treatments, I find that anthocyanin content strongly predicts both community diversity and composition, with high-anthocyanin plants supporting greater diversity while excluding potentially pathogenic taxa that dominate low-anthocyanin plants. This work demonstrates that host chemical traits can mechanistically filter fungal colonization, revealing that while naturally occurring population-level variation may be insufficient to structure communities (Chapter II), experimental manipulation of genetic variation exposes underlying trait-based mechanisms. This establishes that secondary metabolite variation represents a fundamental organizing principle in foliar microbiome assembly, with implications for understanding how plant chemical diversity shapes microbial communities and how these interactions might evolve or be manipulated.
Taken together, this work establishes a hierarchical framework where regional dispersal patterns, local environmental filtering, and host chemical traits interact across scales to shape microbial community assembly in natural ecosystems. By revealing which processes operate at which scales and identifying specific mechanisms of host filtering through experimental manipulation in wild plant populations—an approach rarely applied to research on foliar endophytes—this dissertation provides a conceptual foundation for understanding the community assembly frameworks that shape plant microbiomes.Mueller, Taz. (2025). Untangling spatial, environmental, and genetic drivers of foliar endophyte community assembly. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278794
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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