1,720,956 research outputs found
SXT-related integrating conjugative element and IncC plasmids in Vibrio cholerae O1 strains in Eastern Africa
No full textObjectives: The objective of this study was to investigate the extent of resistance patterns and associated
mobile genetic elements in epidemic V. cholerae O1 El Tor strains isolated from Eastern Africa in
the late 1990s.
Methods: Self-transmissible genetic elements and associated clusters of genes encoding resistance
were detected by conjugation experiments. Detection of SXT-related integrating conjugative elements
(ICEs) and associated antibiotic resistance genes was performed by PCR to amplify the SXT elementintegrase
gene (int), right SXT element-chromosome junction (attP-prfC) and genes conferring resistance
to chloramphenicol (floR), sulfamethoxazole (sulII), streptomycin (strA) and trimethoprim (dfrA1).
Genomic relatedness was established by random amplified polymorphic DNA patterns.
Results: Of 224 strains analysed, 200 isolates exhibited resistance to four or more antimicrobials. An
IncC plasmid, encoding resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and
trimethoprim, conferred multidrug resistance to 113 strains isolated from Somalia and Ethiopia, whereas
an SXT-related ICE, encoding resistance to chloramphenicol, streptomycin, sulfamethoxazole and
trimethoprim, conferred multidrug resistance to 74 strains isolated from Sudan, Kenya and Tanzania.
Conclusions: This study has shown the spread of SXT-related ICEs among V. cholerae O1 African isolates.
It has also highlighted the role of two distinct genetic elements in conferring multiple resistance to
the two distinct groups of V. cholerae O1 strains that, in the late 1990s, spread through Eastern Africa, a
critical geographic region for the persistence and transmission of cholera to the entire continent
Clonal relationship among Vibrio cholerae O1 El Tor strains isolated in Somalia
No full textOne hundred and three Vibrio cholerae O1 strains, selected to represent the cholera outbreaks which occurred in
Somalia in 1998–1999, were characterized by random amplified polymorphic DNA patterns, ribotyping, and
antimicrobial susceptibility. All strains showed a unique amplified DNA pattern and 2 closely related ribotypes (B5a
and B8a), among which B5a was the more frequently identified. Ninety-one strains were resistant to ampicillin,
chloramphenicol, spectinomycin, streptomycin, sulfamethoxazole, and trimethoprim, conferred, except for spectinomycin,
by a conjugative plasmid IncC. These findings indicated that the group of strains active in Somalia in the late
1990s had a clonal origin
Clonal relationship among Vibrio cholerae O1 El Tor strains causing the largest cholera epidemic in Kenya in the late 1990s.
No full textEighty Vibrio cholerae O1 strains selected to represent the 1998-to-1999 history of the largest cholera epidemic in Kenya were characterized by ribotyping, antimicrobial susceptibility, and random amplified polymorphic DNA patterns. Except for 19 strains from 4 local outbreaks in North Eastern Province along the Somalia border, the other 61 strains from 25 outbreaks occurring in districts scattered around the country were all ribotype B27 and resistant to chloramphenicol, spectinomycin, streptomycin, sulfamethoxazole, and trimethoprim. The 61 strains showed similar and specific amplified DNA patterns. These findings indicate that the predominant strains that caused the Kenyan epidemic had a clonal origin and suggest that ribotype B27 strains, which first appeared in West Africa in 1994, have had a rapid spread to eastern Africa
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
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