1,720,966 research outputs found
Attenuation of bunyavirus replication by modification of genomic untranslated regions
No full textBunyamwera orthobunyavirus (BUNV) is the prototype for the family Bunyaviridae.
BUNV has a tripartite RNA genome of negative polarity composed of the large(L),medium (M)and small(S)segments. Each segment contains an open reading frame (ORF) flanked by untranslated regions (UTRs). The eleven terminal nucleotides are conserved between the three segments while the internal regions are unique. The UTRs play an important role in the virus life cycle by promoting transcription, replication and encapsidation of the viral genome.The work presented in this thesis explores UTRs plasticity and examines ways to engineere attenuated viruses by modifying only their UTRs. Using reverse genetics, mainly two ways of attenuation were explored: rescue of viruses either carrying deletions within their 3’ and/or 5’ UTRs in all three segments, or of viruses carrying one segment bearing heterologous UTRs. Both approaches resulted in virus attenuation in tissue culture, with viruses producing smaller plaques or even no plaques, and growing to lower titres than wild-type BUNV. Through serial passage, viruses were shown to
regain some level of fitness while the mutations introduced in the UTRs proved to be stable. Thus, to investigate the mechanism behind fitness recovery, the nucleotide sequence of the entire genome of viruses with deletions in their UTRs was determined. Amino acid changes were observed in the viral polymerase (L protein) of most mutant viruses and the vast majority of the amino acid changes occured in the C-terminal region. The function of this domain is unclear to date, however data obtained using a mini-replicon assay suggest that the
C-terminal domain of the L protein might be involved in UTR recognition. Full genome
sequencing also allowed the identification of an amino acid mutation within the polymerase that resulted in a temperature sensitive phenotype when introduced in an otherwise wild-type BUNV. Thus, it was shown that mutations introduced within the UTR regions of the genome were stable through serial passage and resulted in attenuation. Such a strategy could be used in
combination with mutations of the ORF to design live-attenuated vaccines against serious pathogens within the family Bunyaviridae
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
Ménage à trois: virus, host, and microbiota in experimental infection models
No full textInfections of mammals with pathogenic viruses occur mostly in the polymicrobial environment of mucosal surfaces or the skin. In recent years our understanding of immune modulation by the commensal microbiota has increased dramatically. The microbiota is today accepted as the prime educator and maintainer of innate and adaptive immune functions. It became further apparent that some viral pathogens profit from the presence of commensal bacteria and their metabolites, especially in the intestinal tract. We further learned that the composition and abundance of the microbiota can change as a consequence of acute and chronic viral infections. Here we discuss recent developments in our understanding of the triangular relationship of virus, host, and microbiota under experimental infection settings
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
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