1,720,960 research outputs found
Shewanella algae and Vibrio spp. strains isolated in Italian aquaculture farms are reservoirs of antibiotic resistant genes that might constitute a risk for human health
No full textThe aquatic environment can represent a reservoir of antimicrobial resistance genes. In the present study, phenotypical, biochemical and molecular techniques were used to screen a collection of marine strains isolated in Italian aquaculture farms to investigate their beta-lactam resistance profiles. The genome of 12 carbapenemase and/or beta-lactamase producing strains was sequenced and a phylogenetic analysis of the beta-lactamases found in their chromosomes was performed. Gene annotation and prediction revealed the presence of blaAmpC and blaOXA-55-like in all the Shewanella algae isolates whereas in Vibrio anguillarum and Vibrio parahaemolyticus strains, blaAmpC and blaCARB-19 were found, respectively. Multiple alignments of OXA-55-like and AmpC protein sequences showed different point mutations. Finally, comparisons between enzyme phylogeny and strain clusterization based on sampling sites and dates indicate the diffusion of specific Multi Drug Resistant (MDR) Shewanella algae clones along the Italian Adriatic coast
P139 Hypermutation as an evolutionary mechanism for Achromobacter spp. in cystic fibrosis lung infection
No full textObjectives: Achromobacter spp. can cause chronic infections in the lungs of CF patients. One of the main mechanisms favouring the persistence of CF pathogens is hypermutation, in which defects in DNA repair processes promote an increased DNA mutation rate. In this study, longitudinal isolates were screened to verify the occurrence of hypermutators. Methods: 34 Achromobacter spp. clinical isolates were longitudinally collected over 3 years from 10 patients (CF Center of Verona, Italy) and underwent whole genome sequencing. Phylogenetic and variant analyses were performed. Presence of high impact mutations in mismatch repair (MMR) system genes, transition/transversion (ts/tv) ratio >3 and variant rate >3 were arbitrarily defined as criteria for hypermutation. Results: According to sequencing and phylogenetic analyses, 3 species of Achromobacter spp. were identified: A. xylosoxidans (25 isolates, 7 patients), A. rhulandii (4 isolates, 1 patient) and A. insuavis (5 isolates, 2 patients). MMR genes analysis showed that all A. rhulandii and A. insuavis genomes presented 2 copies of mutS gene while a single copy was detected in A. xylosoxidans genomes. Regardless of the species and number of mutS gene copies, 21 isolates (7 patients) overall were identified as hypermutators: they presented high impact mutations in either mutS, mutL, or mutT, high ts/tv ratio and increased mean yearly variant rate. Conclusions: Most of the enrolled patients (70%) with chronic infection presented hypermutators strains. Such a high prevalence confirms the occurrence and importance of hypermutation as an adaptive mechanism in Achromobacter spp. infection. Hypermutation could potentially influence the clinical outcomes and the efficacy of treatments, highlighting the need to clarify its impact in order to develop appropriate therapeutic regimens. Acknowledgments: This study was supported by the Italian CF Research Foundation (project FFC#18/2019)
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
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