1,721,050 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Primary Stability Of Cementless Anchored Primary And Revision Cup Designs In Various Acetabular Bone Defect Situations
No full textBackground
The primary stability of cementless anchored acetabular cups is essential for the osseointegration of the implant. Factors influencing primary stability include diametral press fit, design and surface topography of the implant [1-3], bone density [4], and acetabular defect situation [5].
Objectives
Our present experimental study aims to evaluate the primary stability of primary vs. revision cup designs in various acetabular bone defects. To evaluate primary implant stability, both lever-out and torsional moments are determined in artificial bone models.
Study Design & Methods
A primary cup (Plasmafit Plus) and a revision cup design (Plasmafit Revision, both Aesculap, Tuttlingen, Germany) were tested. These were pressed into bone models (Sawbones 20 pcf, Malmö, Sweden) in a position-controlled manner using a universal testing machine (Z050, ZwickRoell GmbH & Co. KG, Ulm, Germany). The bone models represented an intact acetabular bone situation, a "medium defect" and a "large defect" situation according to Schulze et al. [5]. The specimens were evenly divided for further lever-out or torsional testing (n = 5 per group).
The lever-out test was performed using a universal testing machine by applying a force to a rod that was centrally connected to the cups. Accordingly, the bone-implant interface was loaded with a tilting moment in inferior direction. Furthermore, torsional testing was carried out with a servo-hydraulic biaxial testing machine with a constant axial load of 500 N. The torsional moment was applied to a rod, which was also centrally fixed to the cups. The lever-out and torsion tests were performed until failure of the bone-implant interface, i.e. until complete loosening of the implants occurred.
Results
The lever-out moments of the primary cup were 13.8 ± 0.8 Nm, 7.3 ± 0.6 Nm, and 5.0 ± 0.3 Nm and for the revision cup 13.7 ± 0.9 Nm, 8.6 ± 0.8 Nm, and 7.0 ± 0.7 Nm in case of the intact bone model, medium defect, and large defect situation, respectively. Hence, the revision cup achieved 17 % (medium defect) and 40 % (large defect) higher maximum lever-out moments than the primary cup.
The maximum torsional moments of the primary cup were 67.3 ± 4.3 Nm, and 51.0 ± 3.8 Nm while the revision cup showed 68.9 ± 2.3 Nm, and 56.9 ± 1.3 Nm in the case of the medium defect, and large defect situation, respectively. Within the intact bone model, the torsional moments were so high that the connection between the cup and the rod fractured. Therefore, no values were detected. Hence, the revision cup achieved 2 % (medium defect) and 12 % (large defect) higher torsional moments than the primary cup.
Conclusions
In both the lever-out and torsion tests, both cup designs showed differences in primary stability depending on the acetabular defect situation. The revision cup design led to higher lever-out and torsional moments than the primary cup in all load scenarios.
References
1 Amirouche et al. 2014, ClinBiomech, 29(10), S. 1177-1185
2 Weißmann et al. 2018, Metals, 8(10), S. 839
3 Saleh et al. 2008, AmJOrthop, 37 (10), S. 519–522
4 Schulze et al. 2019, ComputMethodsBiomechBiomedEngImaging, 22(1), S. 25–37
5 Schulze et al. 2020, J.Arthroplasty, 35(6), S. 1720-172
Kinematics and kinetics comparison of ultra-congruent versus medial-pivot designs for total knee arthroplasty by multibody analysis
Get PDFVariations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
