1,720,971 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
Description of a new group of variants of the Staphylococcus aureus elastin-binding protein that lacks an entire DNA segment of 180 bp
No full textThe elastin-binding protein (EbpS) is a microbial surface component recognizing adhesive matrix molecule (MSCRAM) found in Staphylococcus aureus that mediates bacterial cell binding to soluble elastin and tropoelastin. In scientific literature it is well established that the gene encoding for the elastin-binding protein (ebpS) is present in the vast majority of Staphylococcus aureus
clinical isolates. The present study aimed at investigating a group of new variant forms of ebpS gene identified in S. aureus clinical strains isolated from implant-related orthopedic infections. A PCR
screening for the ebpS gene, conducted on over two hundred S. aureus clinical isolates from implant-related infections revealed the detection of six strains exhibiting an altered amplicon size, shorter than expected. In order to elucidate the sequence changes present in these gene variants, the trait comprised between the primers was analyzed in all six isolates bearing the modification and in four isolates exhibiting the regular amplicon size. A similar form of the ebpS gene, lacking a DNA trait of 180 bp, was confirmed in all six isolates independently of their clonal origin. Interestingly, only three of these isolates, all with type IV polymorphism of the accessory genes regulator (agr) locus, showed exactly the same sequence and, thus, the same pattern of point mutations with respect to reference strains. From nucleotide translation, the corresponding encoded protein was found to lack an entire peptide
segment of 60 amino acids. From nucleotide sequence translation, this modification was found to implicate the disappearance of an entire hydrophobic domain, whose functional significance needs to
be further investigated
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
The presence of both bone sialoprotein-binding protein gene and collagen adhesin gene as a typical virulence trait of the major epidemic cluster in isolates from orthopedic implant infections
No full textStaphylococcus aureus is a major, highly clonal, pathogen causing implant infections. This study aimed at investigating the diverse distribution of bacterial adhesins in most prevalent S. aureus strain types causing orthopaedic implant infections. 200 S. aureus isolates, categorized into ribogroups by automated ribotyping, i.e. rDNA restriction fragment length polymorphism analysis, were screened for the presence of a panel of adhesins genes. Within the collection of isolates, automated ribotyping detected 98 distinct ribogroups. For many ribogroups, characteristic tandem genes arrangements could be identified. In the predominant S. aureus cluster, enlisting 27 isolates, the bbp gene encoding bone sialoprotein-binding protein appeared a typical virulence trait, found in 93% of the isolates. Conversely, the bbp gene was identified in just 10% of the remaining isolates of the collection. In this cluster, co-presence of bbp with the cna gene encoding collagen adhesin was a pattern consistently observed. These findings indicate a crucial role of both these adhesins, able to bind the most abundant bone proteins, in the pathogenesis of orthopaedic implant infections, there where biomaterials interface bone tissues. This study suggests that specific adhesins may synergistically act in the onset of implant infections and that anti-adhesin strategies should be targeted to adhesins conjointly present
Scenery of Staphylococcus implant infections in orthopedics
No full textInfection is still the major complication of orthopedic implants and projections based on the actual trend indicate that total hip and knee arthroplasties and their consequent infection burden are destined to greatly increase. Staphylococcus aureus and Staphylococcus epidermidis are the leading etiologic agents of orthopedic implant infection. Here we report on epidemiology of implant-related Staphylococcus infections in orthopedics, also referring to our experience, and focus on the crucial role of bacterial adhesins and on their ability to direct the pathogenesis process. Bacteria initiate implant infection by adhering to biomaterials. In the early steps of infection, adhesins mediate the specific interaction between microbial cells and the extracellular matrix proteins filming biomaterial surface. Then adhesin-mediated anchorage allows bacteria to cling to the biomaterial surface and to produce a biofilm that favors their ability to resist antibiotics. With the aim to prevent implant-related infections, anti-infective and infection-resistant biomaterials are being developed. The research for novel therapeutic strategies is incited by the emergence of antibiotic-resistant bacteria. Vaccines against the adhesins or antisense molecules against virulence genes can open a future in combating implant infections
- …
