1,721,117 research outputs found
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
The role of lipid a head group modification in Escherichia coli virulence and polymyxin resistance
Full text linkThe use of natural antimicrobials as antibiotics has divested considerable clinical benefit, with the consequence being that pathogenic species are well-prepared to counteract their effects in new, clinical settings.
When considering antimicrobial resistance, the ecological origins of an antibiotic class can direct the conditions under which resistance is promoted, or constrained. By inducing protective transcriptional regulation, bacteria quickly reconcile with otherwise bactericidal compounds in their local environment. The polymyxin antibiotics, Polymyxin B and Colistin, are highly efficacious against pathogenic Gram-negative bacteria, but are nevertheless overcome by such resistance mechanisms. This has been ascribed to the similarities between polymyxins and endogenous cationic antimicrobial peptides, which must be deflected by commensal bacteria and pathogens alike to survive within a variety of hosts.
To repel cationic antimicrobials, bacteria activate transcriptional pathways that reduce the intrinsic anionic charges of the cell envelope. Polymyxin resistant Klebsiella pneumoniae, and Escherichia coli possess both the arnBCADTEF-ugd and eptA operons, expression of which modifies lipid A with the cationic L-Ara4N and pEtN moieties respectively. Electrostatic repulsion of polymyxins by either moiety alone is sufficient for Pseudomonas aeruginosa and Acinetobacter baumannii to attain therapeutically dangerous levels of polymyxin resistance, raising questions as to why certain Enterobacteriaceae maintain both.
The aim of this study was to investigate non-pathogenic E. coli strain BW25113 and the isogenic single deletion strains BW25113ΔarnT, and BW25113ΔeptA. Each mutant strain lacks the final transferase necessary for modification with either L-Ara4N (ArnT), or pEtN (EptA). By constraining E. coli to a singular modification type, the relative influence each moiety exerts on both polymyxin resistance, and pathogenically relevant phenotypes can be uncovered.
Due to their role in eroding polymyxin efficacy, and enhancing pathogenesis, both ArnT and EptA are potential candidates for antivirulence drug design. Therefore, bioinformatics analyses of both enzymes were conducted between E. coli BW25113 and select Gram-negative pathogens.
Homologous enzymes demonstrated preservation of key sites implicated in catalysis, indicating that inhibitors designed to disrupt activity in E. coli may have a broad-spectrum action. Parallel phenotypic assessment of E. coli ArnT and EptA mutant strains under polymyxin exposure, acidification, and within the J774.A1 macrophage survival model suggests that E. coli can readily compensate for individual deficiencies in lipid A modification. This raises implications for the sole pursuit of either enzyme to conquer burgeoning polymyxin resistance, as the Enterobacteriaceae appear to be “ambidextrous” with regard to their preference for ArnT or EptA
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
The genetic factors responsible for daptomycin non-susceptible Staphylococcus aureus isolates in Australia
Full text linkDaptomycin (DAP) is used as a last-line antibiotic to treat S. aureus infections. However, there has been an increase in the number of publications reporting DAP non-susceptibility (DNS). Extensive research on DNS has identified an association with an elevated DAP minimum inhibitory concentration (MIC) and the acquisition of single nucleotide polymorphisms (SNPs) in specific genes.
In this study, the reported SNPs in nine different genes (asp23, asp23a, cls, dsp1, mprF, pgsA, rpoB, rpoC, and walK) were investigated in 171 DAP non-susceptible (DAP-NS) S. aureus genomes to establish whether these SNPs were correlated to a particular DAP MIC value. The genetic diversity of S. aureus isolates was also investigated to determine whether DNS was linked to one specific sequence type. Screening for other antimicrobial resistance genes was also conducted. Lastly, the genomes of ST22 DAP susceptible (DAP-S) and DAP-NS isolates were compared to identify any significant differences in the genes associated with DNS. The results in this study demonstrated DNS was not associated with one particular sequence type. DNS, however, was observed in a genetically diverse population (47 sequence types), which had no impact on the MIC value. The majority of isolates (61.8%, n = 102/165) had one of the previously reported SNPs (S295L, P314L, S337L, L341S, T345A/I, V351E, I420N, and L826F) in the mprF locus. These SNPs, however, were not associated with one particular DAP MIC value. A cross-resistant relationship was not identified in this study. Distinct differences between DAP-S and DAP-NS ST22 isolates was observed. DAP-NS isolates had a more genetically diverse mprF gene compared to DAP-S isolates. All DAP-S isolates did not contain any of the previously
reported SNPs in any of the genes, including mprF, supporting the role of these SNPs in DNS.
This study has indicated DNS is highly variable regarding the acquisition of SNPs in genes previously associated with DNS. Evidence provided by this study also suggests DNS is not a result of clonal expansion in Australia, as seen by the genetically diverse population in the study
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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