1,721,012 research outputs found
Prospects and limits of indicator viruses for the monitoring of virus-contaminated surface waters
No full textHumanpathogene Viren, die durch unzureichend oder ungeklärtes Abwasser in die Umwelt gelangen,können ein Gesundheitsrisiko für die Bevölkerung darstellen. Da die derzeitig verwendeten Fäkalindikatoren keine Viren einschließen und ein anderes Verhalten als diese im Wasser zeigen, wird derzeit nach potentiellen Kandidaten unter den Viren gesucht, die eine Indikatorfunktion übernehmen könnten. Darüber hinaus werden verlässliche Nachweissysteme benötigt, um eine sinnvolle Risikobewertung gewährleisten zu können. In der vorliegenden Arbeit wurden verschiedene Konzentrierungsmethoden in Bezug auf die Wiederfindung von Viren aus künstlich kontaminierten und nativen Labor- und Umweltproben miteinander verglichen. Als Viren wurden hierbei humanpathogene Adenoviren und Noroviren sowie intestinale Bakteriophagen eingesetzt, die allesamt als mögliche Indikatorviren gelten. Die Ergebnisse der Analysen zeigen, dass die hierbei angewandte Monolithische Affinitätsfiltration eine vielversprechende Methode darstellt, mit der auch in großen Volumina gute Wiederfindungsraten erzielt werden könnten. Im Gegensatz zu traditionellen Methoden, wie der Glaswollefiltration und der Ultrazentrifugation, variierten die Ergebnisse mit dieser Methode jedoch noch stark, weswegen weitere Entwicklungsarbeit benötigt wird. Während Adeno- und Noroviren über eine quantitative Polymerasekettenreaktion (qPCR) nachgewiesen wurden, erfolgte die Quantifizierung der Phagen über den Nachweis von Plaques. Der Nachweis von Viren in Umweltproben kann jedoch durch inhibierende Stoffe verhindert werden und insbesondere qPCR-Systeme zeigen eine hohe Anfälligkeit gegenüber solchen Substanzen. Aus diesem Grund wurden Methoden untersucht, mit denen sich Inhibitoren aus Umweltproben entfernen lassen. Die Kombination einer Nukleinsäureextraktion mittels NucliSens Extraktionskit und MobiSpin Säulen ermöglichte einen Nachweis auch noch in Laborproben, die Huminsäurekonzentrationen von bis zu 400 ng/μl enthielten, während die Grenze der Bestimmbarkeit ohne Aufreinigungsschritte bei 4 ng/μl lag. Die Anwendung der MobiSpin Säulen erlaubte auch eine bessere Quantifizierbarkeit in inhibierenden Umweltproben. Die Qualität der qPCR-Ergebnisse wurde weiterhin mit verschiedenen Kontrollsystemen untersucht, die in der Arbeit vorgestellt und diskutiert werden. Daneben wurden Möglichkeiten zur Identifizierung von Virusserotypen in Umweltproben und ihrer Diversität mittels Restriktionsfragmentanalyse, Denaturierender Gradientengelelektrophorese und Schmelzkurvenanalytik untersucht. Soweit dies ermittelt werden konnte, wurden die Methoden der Denaturierenden Gradientengelelektrophorese und der Schmelzkurvenanalytik nicht zuvor für die Analyse von Adenoviren in Umweltproben beschrieben. Alle drei Methoden ließen eine Unterscheidung verschiedener Serotypen zu, die Schmelzkurvenanalytik war im Gegensatz zu den übrigen Methoden jedoch mit weit geringerem Aufwand durchführbar. Die Untersuchung von abwasserkontaminierten Proben deutete darauf hin, dass sich Serotyp hAdV41 von den bekannten humanpathogenen Adenovirus-Serotypen am besten als Indikator eignen würde, da er in allen Proben nachgewiesen wurde.Human pathogenic viruses, released into the environment by insufficient or untreated sewage, may be a threat to public health. Current indicators for fecal pollution do not include viruses and their ability to survive outside their hosts and their properties differ from those of the viruses. Therefore, potential candidates, which could be used as viral indicators for sewage pollution are investigated around the world. Furthermore, reliable detection systems are needed, to ensure meaningful risk assessments. For this purpose, different concentration methods were tested and compared with regard to recovery rates of viruses in native and spiked laboratory and environmental samples. Human pathogenic adenoviruses and noroviruses as well as enteric bacteriophages were used for spike experiments. All of these were previously regarded as potential indicator viruses. Results show, that high recoveries can be received even from samples with large volumes, using the tested monolithic affinity filtration system. However, in contrast to traditional methods, like glass wool filtration and ultracentrifugation, results varied and further evaluation is required. While adenoviruses and noroviruses were quantified by quantitative real-time polymerase chain reaction (qPCR), quantification of phages was performed by plaque assays. Detection methods may be subject to inhibitory substances within environmental samples. In particular, quantitative real-time polymerase chain reactions are at risk to fail, when inhibitors are present. Methods were investigated in order to eliminate relevant substances from environmental samples. By combining a nucleic acid extraction using the NucliSens extraction kit with MobiSpin column purification, quantification was possible in laboratory samples containing up to 400 ng/μl of humic acids. Without further treatment reliable quantification was not possible above 4 ng/μl. Moreover, application of MobiSpin columns improved quantification limits in inhibited environmental samples. The quality of qPCR results was controlled by different systems, that are discussed in the course of this thesis. Investigation of virus serotypes in environmental samples was performed, using restriction fragment analysis, denaturing gradient gel electrophoresis and melting point analysis as tools. To the best of my knowledge, denaturing gradient gel electrophoresis and melting point analysis were never before used to analyze adenovirus diversities in environmental samples. Discrimination of different adenovirus serotypes was possible using all three systems, but in contrast to restriction fragment analysis and denaturing gradient gel electrophoresis, melting point analysis was less complex and time-consuming. Examination of sewage contaminated samples indicated, that serotype hAdV41 is probably the most suitable candidate of the known human pathogenic adenovirus serotypes. Its stability was comparable to other serotypes, but it was the only serotype detected in all samples
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
- …
