1,720,953 research outputs found
Demographics of alien willows in the Grassland Biome of South Africa
No full textDissertation (M.Sc.(Botany))--University of the Free State, 2024Invasive alien species present a critical threat to biodiversity, ecosystem services, and agricultural productivity worldwide. This study examines the distribution, demographic dynamics, and ecological impacts of L. (weeping willow) and L. (crack willow) within the Grassland biome of the Eastern Free State, South Africa. These invasive species, introduced for ornamental and functional purposes, have shown extensive colonization, particularly in riparian zones, where they outcompete native vegetation and alter hydrological processes.
The research combines historical and contemporary data sources to evaluate changes in the population structure and spatial distribution of these species over time. Using aerial photographs from 1984 and 2023, supplemented with roadside surveys and Google Street View (GSV) analysis, the study provides an assessment of the species’ demographics. Additionally, field-based verification of GSV-derived data validates its utility as a cost-effective tool for mapping and monitoring invasive alien plants.
The study confirms that . and . remain prevalent along watercourses, roadsides, and disturbed areas, with . exhibiting a broader distribution along roadsides with approximately 50% of the sites having a population size of 1-5 trees. Although . is not as widely distributed as . it dominates the areas in which it is found, forming pure stands; 56% of the sites surveyed consisted of 6 or more trees. Gender analyses of . populations reveal a predominance of female trees which suggests that its propagation is mainly asexual.
The demographic study done through road surveys and GSV reveals limited recruitment of . in recent decades, suggesting a potential decline in its invasive potential with almost 80% of the population consisting of adult or dying trees. In contrast, . populations display a continuous expansion with healthy recruitment, with 44% of the trees recorded as seedlings, young trees, or mature trees. This expansion indicates that . is now more invasive than . , which increases the need for a tailored management strategy to address this invasive species.
The research also investigates interactions between invasive willows and invertebrate communities. Surveys at selected sites document the presence of 348 individual insects and one arachnid, representing 21 families, with 14 species associated with both willow species. Another finding was the presence of crown galls on 27.5% on the . population surveyed. Invasive willows provide habitat and resources for certain insect populations. Some of these insects, specifically , , along with gall-inducing bacteria (potentially ), recorded within the . populations could be resulting in the decline of this invasive species.
This study explored the use of ArcGIS and GSV, to assess invasive tree distributions and potential of these tools to monitor the spread of invasive trees over time. The comparison of historical and current data reveals significant efficiency of GSV as a monitoring tool, offering a cheap and quick approach to invasive species management in resource-limited settings.
Policy implications of the findings are discussed with reference to South African legislation, including the Conservation of Agricultural Resources Act (CARA) of 1983 and the National Environmental Management: Biodiversity Act (NEMBA). and . have been classified as Category 2 invaders under CARA but are not found under the NEMBA Act. This may result in challenges in effectively controlling . and . .
This dissertation contributes to the field of biological invasions by providing an updated assessment of invasive willows in the Grassland biome, thereby offering insights for land managers, conservationists, and policymakers. The study concludes by emphasizing the importance of integrating historical data and modern geospatial tools, as an informative approach to develop effective management solutions for invasive alien plants. The methodological framework and findings presented herein offer valuable lessons for addressing invasive species challenges in similar ecological contexts globally
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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