1,720,953 research outputs found
Assessing the cyto-genotoxic impacts of un-neutralised and pH-neutralised acid mine drainage on the human breast cancer cell line, MCF-7
Get PDFThesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: The use of toxicity tests to evaluate the quality of streams affected by mixtures such as acid mine drainage (AMD), adds value to assessments whereby site-specific toxicological data may identify toxicants that pose a threat to humans. To successfully evaluate the risk of combined mixtures, an improved understanding of the individual components, their uptake, metabolism, excretion and mode of action is required. This study aimed to identify the extent of AMD toxicity in a dose dependant manner on the MCF-7 cell line. The first study site associated with gold mining was chosen as the Tweelopies Stream situated in the Gauteng province of South Africa. The AMD effluent (un-neutralised) contaminating the Tweelopies Stream had undergone pH-neutralisation using a reactor-bed limestone technology incorporating the use of both calcium carbonate (CaCO3) powder and limestone beds. The second study site, the Kromdraai River, is situated in the eMalahleni region of South Africa where a predominance of coal mining exists. The pH -neutralisation of the AMD (un-neutralised) contaminated Kromdraai River was performed using a caustic soda (NaOH) precipitation technique. This study demonstrated the rapid and effective application of the comet assay as a screening tool for AMD-associated DNA breakages in the human cell line, MCF-7. Moreover, the study analysed parameters of cellular survival, DNA fragmentation and variations in morphologies indicative of cellular death. Collectively, the cyto-genetic aberrations observed in the MCF-7 cells as a result of exposure to gold and coal mining associated AMD, confirms the urgency of incorporating high-throughput screening in ecological toxicity assessment to evaluate cellular damage at genetic levels in low dose exposures where detection might be missed.AFRIKAANSE OPSOMMING: Die gebruik van toksisiteitstoetse om die gehalte van strome te evalueer wat geraak word deur mengsels soos suur mynwater (SM), gee waarde aan spesifieke toksikologiese data van gifstowwe wat 'n bedreiging vir die mens kan identifiseer. Om die risiko van gekombineerde mengsels en hul individuele komponente beter te begrip en suksesvol evalueer, is hul opname, metabolisme, uitskeiding en modus van aksie nodig. Hierdie studie het gepoog om die omvang van SM-toksisiteit in 'n dosis afhanklike wyse op die MCF-7-sellyn te identifiseer. Die eerste studie-area wat gekies is, hou verband met goudmyn-ontginning, en is die Tweelopiesspruit, geleë in die Gauteng-provinsie van Suid-Afrika. Die SM-uitvloeisel (on-geneutraliseerde) wat die Tweelopiesspruit besoedel, het pH-neutralisasie ondergaan met behulp van die integrasie van 'n reaktor-bed kalksorpsietegnologie wat gebruik maak van beide kalsiumkarbonaat (CaCO3) poeier en kalksteenbeddens. Die tweede studie-area, is die Kromdraairivier geleë in die eMalahleni-streek van Suid-Afrika, waar steenkoolontginning die oorheersende aktiwiteit is. Die pH-neutralisasie van die SM (on-geneutraliseerde) in die geval van die Kromdraairivier word met behulp van 'n bytsoda (NaOH) neerslag tegniek, uitgevoer. Hierdie studie het die komeet-toets getoon as 'n vinnige en doeltreffende toepassing vir SM-geassosieerde DNA-breekskade in die menslike sel lyn, MCF-7. Verder het die studie parameters van sellulêre oorlewing, DNA-fragmentasie en variasies in sel morfologieë wat ‘n aanduiding van sellulêre dood is, ontleed. Gesamentlik dui die resultate daarop dat die sitogenetiese afwykings wat in die MCF-7-selle waargeneem is, as 'n gevolg van blootstelling aan goud- en steenkool-geassosieerde SM is. Die studie het verder die dringendheid van die integrasie van hoë-deurset tegnologieë in ekologiese toksisiteitstoetse in selle wat genetiese skade mag ondergaan, na 'n lae dosis blootstelling waar opsporing dalk gemis word, ondersteun.Master
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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