1,720,961 research outputs found
Application of Machine Learning algorithms to essential oils to develop classification models of quantitative composition-activity relationship (QCAR)
No full textIn this study, the relationship between the chemical composition of essential oils and antibacterial activity against carbapenemase-resistant Acinetobacter baumannii (CRAB) was investigated, exploiting the capabilities of machine learning (ML) algorithms to identify the chemical components most responsible for the experimentally observed biological profile. Four ML models were generated and used to predict the antibacterial activity of 11 experimentally extracted essential oils whose antibacterial activities were evaluated. Two different training sets were compiled, and two separate calculations were performed for each dataset, one for Minimum Inhibitory Concentration (MIC) and the other for Minimum Bactericidal Concentration (MBC) values. The data were extracted from the PyEO database (eo.3d-qsar.com) and then processed on the Jupyter Notebook platform. The datasets were subjected to optimization using a Monte Carlo approach. The final models were analyzed through the Skater library, first determining the Features Importance (FI) for each component and then the Partial Dependence (PD). The PD emphasizes the positive or negative influence of each component within the essential oil against the associated biological activity. The four generated models were experimentally validated using an external test set of 11 essential oils.
For both datasets, models with higher accuracy were obtained by separating essential oils into active and inactive with a cutoff value of 0.03% v/v (MIC or MBC). The FI analysis defined that carvacrol, eugenol, thymol, limonene, and eucalyptol were found to be the most influential on antibacterial activity, while for PD analysis carvacrol, eugenol, and thymol revealed positive influence according to their concentration within the essential oils. Limonene and eucalyptol, on the other hand, were assessed to negatively influence antibacterial activity. A mixed result was observed in the case of α-pinene, probably related to a synergistic or anti-synergistic effect depending on the percentage present. External validation of these four optimized models on the 11 essential oils with unknown activity toward CRAB predicted that only the essential oil extracted from Thymus vulgaris would have an activity less than 0.03% v/v. Microbiological tests determined MIC values in a range from 1.25% v/v to >5% v/v. By PD analysis a series of chemical components were selected, and their antibacterial activity was experimentally verified. In agreement with the PD data, the data confirmed an excellent MIC and MBC value for thymol (0.3% v/v) and carvacrol (0.3% v/v) and higher values for compounds such as eucalyptol and α-pinene, 2.5% v/v and 5% v/v, respectively.
Of the eleven essential oils experimentally tested, the models correctly predicted that ten samples (91%) had no MIC values below 0.03% v/v. In addition, the PD analysis was confirmed by experimentally obtained data on some chemical components. In light of these results further studies are underway to develop increasingly robust and predictive models that can be used in the future to design "ad hoc" essential oil blends containing mainly the major components indicated by the ML models. The application of machine learning to essential oils thus represents an innovative perspective to address the threat of A. baumannii, paving the way for new natural and sustainable therapies in the fight against multidrug-resistant bacteria
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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