1,720,978 research outputs found
Genomic and bioinformatic approach to avian influenza virus evolution
Get PDFViral zoonotic agents have a significant impact both on human and veterinary public health. Ecosystems changes, increasing urbanization and easy connection have influenced the balance between pathogen and related host species. In recent years most threatening viruses, originated from animal hosts causing emerging diseases; most of them are RNA viruses that thanks to a large population sizes, high mutation rate and short generation time allow rapid evolution, genetic variability and the selection of new variants. A constant and adequate surveillance program and the sharing of different professional expertise are necessaries to follow viral evolution and to formulate efficient public health policy (Howard and Fletcher, 2012).
Influenza A virus is considered one of the most challenging RNA viruses for its zoonotic potential role in the animal-human interface, for global health and economic impact; almost every year influenza epidemics cause morbidity and mortality in the human and is also associated with influenza virus pandemics.
Both wild and domestic birds are considered the primary natural reservoir of influenza A virus and in particular wild birds are thought to be the source of influenza A viruses in all other animals (http://www.cdc.gov/flu/about/viruses/transmission.htm). Different techniques are available to genetically characterize and study viruses in order to understand their behavior, the evolutionary dynamics, the host-virus interactions and their origin; the aim is to develop a valid support with appropriate treatments during the phases of surveillance and diagnosis of possible epidemics.
During my PhD it was used an integrated approach, both genomic and structural, to study the evolution of avian influenza A virus in particular focusing on the hemagglutinin, the major surface glycoprotein, belonging to the H5, H7 and H9 (the major "avian" subtypes responsible for human infection).
Next-generation sequencing (NGS) was used to investigate and characterize the complexity of the viral population to detect low-frequency mutations and to follow the evolution of the genetically related variants present in a viral population. To compare and inspect genetic data, phylogenetic approach has shown to be a useful tools in the analysis of viral evolution. It has been used to explain the molecular epidemiology, transmission and viral evolution. In order to obtain a more complete view of the ‘functional evolution’, phylogenetic analyses based on sequence comparison and resulting in trees, was integrated taking into account information from structural comparison. Three-dimensional structural approach have shown to be a useful tool to display similarities and to inspect motifs that cannot be discovered analyzing primary sequences alone. Indeed, in the primary sequences the introduction of a mutation does not take into account the effect on the protein folding or on the surface properties, while in the three-dimensional structures, since each mutation is able to influence the structural characteristics and interactions, is directly detectable. This approach has also brought a further contribution to the phylogenetic analysis. In particular the study has focused on the evolutionary dynamics and the adaptive strategies of avian influenza H7N1 and H7N3 subtypes that circulated in Northern Italy for similar periods of time under similar epidemiological conditions. Within and between host population dynamics of Avian HPAI H7N7 viruses, that affected Italy during 2013, were investigated using next generation technology. NGS analysis was used to characterize viral population complexity into two groups of animals challenged with the same virus H5N1 HPAIvirus but vaccinated with vaccine conferring different protection levels. An extensive comparison of structural domains and sub-regions was performed on the hemagglutinin of different subtypes of influenza A virus, with particular interest to different clades of HPAI H5N1 circulating in Egypt (where bird flu is endemic in poultry ), to investigate any domain-specific changes.
Influenza A viruses belonging to H9 subtype were inspected from a phylogenetic and a structural point of view to infer type-specific characteristic and confirm if surface properties could be associated to 'functional evolution' of viral surface determinants as seen in H5N1 subtype. This work suggests that integrating genomic, phylogenetic, and structural comparison can help in understanding the 'functional evolution' of avian influenza A virus
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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