1,720,956 research outputs found
Activity of ceftibuten, cefaclor, azithromycin, clarithromycin, erythromycin and telithromycin against Streptococcus pyogenes clinical isolates with different genotypes and phenotypes
No full textBackground: The growing number of macrolide-resistant strains of Streptococcus pyogenes represents an increasing worldwide problem. Macrolide resistance in S. pyogenes is mediated by several different genes, which determine different levels of resistance to macrolides, lincosamides and streptogramin B (MLS). Methods:This study compared the in vitro antimicrobial activity of azithromycin, clarithromycin, erythromycin, ceftibuten, cefaclor, and telithromycin against 287 strains of S. pyogenes by the broth microdilution method. All strains were characterized both phenotypically and genotypically for erythromycin resistance and most of them have been M-typed by means of PCR. Results: Ceftibuten and cefaclor showed the best antimicrobial activity, while MIC values for telithromycin were higher against constitutively MLS (cMLS)-resistant strains rather than against the other phenotypes. Conclusion: Oral cephalosporins retain the best activity against S. pyogenes; showing good activity except for cMLS-resistant strains, telithromycin is a valid alternative to these antimicrobials
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
Characterisation of biofilm-forming Staphylococcus epidermidis clinical isolates
No full textObjective: Staphylococcus epidermidis is one of the bacterial species mainly implicated in foreign body associated infections. We have characterized several S.epidermidis clinical isolates for their ability to form biofilms and their resistance to antibiotics.
Methods: 76 S.epidermidis strains isolated from implantable medical devices have been collected from hospitals of Central Italy. Susceptibility to penicillin, methicillin, erythromycin and tetracycline has been determined in vitro by E-test according to NCCLS guidelines. The specific antibiotic resistance determinants have been checked by PCR (blaZ, mecA, ermA, ermB, ermC, msrA, tetK and tetM). The ability to form biofilms has been determined: (i) by PCR, detecting genes specific for attachment and biofilm development (icaADBC operon, aap, and atlE); (ii) by Congo Red Agar (CRA) plate test to assay the production of polisaccaridic intercellular adhesin (PIA); (iii) by crystal violet (CV) stain to determine the biofilm biomass development on polystyrene microtiter plates; (iv) and by CSLM microscopy observations to investigate biofilm structure.
Results: 94% of the strains under study was resistant to penicillin, 87% to methicillin, 72% to erythromycin and 25% to tetracycline. On the side of biofilm-specific genes detection, 66% of strains was positive to ica operon genes, 82% possessed atlE gene, and 42% aap determinant. In 89% of the population, the CRA test confirmed the correlation between the presence of ica genes and slime expression. The CV assay classified the quasitotality of our strains (97%) as biofilm producers on plastic surface. In addition, the distribution of optical density values (OD540) obtained after CV stain, showed a significant statistical difference in biofilm biomass development between the ica- ADBC-positive strains and the icaADBC-negative ones. Finally, a correlation, although not always present, has been observed between ability of the strains to develop in a high-structureted biofilm and specific biofilm-formation determinants.
Conclusions: The investigated bacterial population shows a very high and alarming level of resistance to all tested drugs. Although the specific determinants for biofilms formation are not always present, nevertheless all the strains are able to develop in sessile form showing that different and not still identified factors could work together in the formation and organization of staphylococcal complex microbial communities
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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