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Parasite diversity and health of chiloglanis pretoriae and amphilius uranoscopus from the Limpopo River System
Get PDFThesis (M.Sc. (Zoology)) -- University of Limpopo, 2023The African continent has rich freshwater fish fauna, but the parasite composition of only a few species is known. Chiloglanis pretoriae Van der Horst, 1931 and Amphilius uranoscopus (Pfeffer, 1889) are among African freshwater fish endemic to South Africa with limited information about their parasite composition and health status. A total of 171 fishes, C. pretoriae (n = 127) and A. uranoscopus (n = 44) from Nwanedi, Mutshundudi, Lutanandwa and Politsi rivers within the Limpopo River System, were collected to determine their parasite diversity and health. Both ecto- and endoparasites were recovered and preserved for identification. Scanning electron microscopy and morphological, morphometric and molecular analysis were used for parasite identification. Parasite infestation indices for all parasites were calculated and compared among the four rivers. The water quality of the rivers was investigated by measuring the selected physico-chemical parameters. Subsurface water samples were collected for analysis of selected metals and nutrients. The Health Assessment Index (HAI) in conjunction with the Inverted Parasite Index (IPI), condition factor (K) and regression analysis were calculated to determine the health of fish. Species richness and parasite diversity of C. pretoriae and A. uranoscopus from the four rivers were calculated using Margalef’s richness index and Shannon-Weiner diversity index, respectively. Parasite diversity and species richness of C pretoriae and A. uranoscopus were compared to the water quality of the four localities. Three parasitic groups (Monogenea, Digenea and Hirudinea) were found from C. pretoriae which comprised of two ectoparasite species [Dactylogyridae gen. sp. (n = 56) and a leech (n = 4)] and three endoparasite species [Clinostomum sp. (n = 4), Diplostomidae gen. sp. larva (n = 143) and Cephalogonimidae gen. sp. (n = 19)]. Ectoparasites were more abundant in the Lutanandwa River with a total of 54, while endoparasites were more abundant in the Mutshundudi River with a total of 106. Diplostomidae gen. sp. from C. pretoriae in the Mutshundudi River had the highest prevalence of 57.14%, and the leech from the Nwanedi River had the lowest prevalence of 0.25%. Chiloglanis pretoriae from Nwanedi River had the highest Shannon-Weiner and Margalef’s index values of 0.53 and 0.54, respectively, indicating a healthy ecosystem. Two endoparasite groups, digeneans (Clinostomum sp., Uvulifer sp. and Cephalogonimidae gen. sp.) and nematodes (Labeonema sp., Contracaecum sp., Rhabdochona sp., Gendria sp. and Gendria cf. paski) were found in A. uranoscopus.
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Uvulifer sp. was the most prevalent parasite with a 100% prevalence. Amphilius uranoscopus from Lutanandwa River had the highest Shannon-Weiner Index and Margalef’s index values of 0.26 and 0.30, respectively, and a low evenness value of 0.37 due to uneven distribution of parasite species. The highest HAI value for C. pretoriae (36.19) was recorded from the Mutshundudi River and the lowest of 28.38 was recorded from the Lutanandwa River. The highest K score for C. pretoriae of 1.08 was recorded from Nwanedi River and the lowest of 1.01 from Lutanandwa River. The HAI of A. uranoscopus from the four selected localities indicated that the fish collected from the Lutanandwa River were in poorer health state than those from the other rivers due to the higher score. The highest HAI of 99.13 was recorded from the Lutanandwa River and the lowest HAI of 36.36 was recorded from the Nwanedi River. However, the highest mean K score of 0.84 was recorded from Nwanedi River while the lowest of 0.53 was recorded from Mutshundudi River. The results of both C. pretoriae and A. uranoscopus also indicated that the parasite burden did not affect the K of the fish. Generally, water quality results indicated that the rivers were in fair condition with most parameters being within the acceptable target water quality range (TWQR) of aquatic ecosystems. These rivers therefore have good water quality and indicate an oligotrophic state, however, Nwanedi and Politsi rivers are slightly impacted by anthropogenic factors which increased their nitrate concentration compared to the other rivers (Mutshundudi and Lutanandwa rivers). During this study, fish health, parasite diversity and species richness indices were used in combination to determine the water quality of the four localities. The results represent new geographical and host records for parasites from C. pretoriae and A. uranoscopus in the Nwanedi, Mutshundudi, Lutanandwa and Politsi rivers. Since it is the first record of Cephalogonimidae gen. sp. and Dactylogyridae gen. sp., more studies should be done to investigate other possible localities within the Limpopo River System and determine the life cycle of the digenean. Since both parasites represent new genera, papers on their description and identification are in preparation. Future studies on the parasites of the two fish species should employ the use of molecular analysis for larval forms as well as the leeches. It is proposed that the HAI using A. uranoscopus and C. pretoriae should not be employed for future studies because not all variables can be used due to the small size of these fish species. It is proposed that the study should be done seasonally at all localities to detect differences in the occurrence of parasites in relation to the seasonal water quality.Department of Science and
Innovation and the National Research Foundation (NRF) of South Afric
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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