1,720,957 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
Fracture resistance of bonded fibre posts with different shape and taper: conventional versus conservative approach
No full textAim: To investigate in vitro the fracture resistance of two different post systems, a conventional one with post space preparation using a drill and an alternative one adapted to the canal shape. Methodology: After sample size calculation, the crowns of 26 single-rooted freshly-extracted teeth were removed with a disc 1 mm coronal to the cemento-enamel junction. The canals were shaped with Mtwo rotary files up to size 40, 0.06 tpaer and filled with the continuous wave of condensation technique leaving the coronal 9 mm of the canal unfilled. After the post space preparation by a dedicated drill, double-tapered fibre posts (DT Light-Post) were cemented in half of the roots (G1, n = 13). 0.06 tapered fibre posts (Tech S Endoshape) were trimmed to fit the canal of the remaining roots (G2, n = 13) and then cemented without post space preparation. A self- adhesive cement (RelyX Unicem) was used in both groups. The posts were cut 5 mm from the root coronal surface. The specimens were embedded in acrylic resin and the top of the post was loaded under continuous compressive force (45°, 0.75 mm/min) to measure the maximum breaking load (N). Data were statistically analyzed by using a Student’s t-test (α = 0.05). Results: The mean maximum breaking loads ±SD were G1 = 164.07 ±21.54 and G2 = 151.22 ±14.69. The difference was not statistically significant (P = 0.093). Only post fractures were detected, with all the roots remaining intact. Conclusions: Within the limitation of the study, conservative posts without post space preparation performed similarly to conventional ones. In order to avoid procedural errors during the post space preparation and to spare tooth structure a conservative approach seems advisable
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
A rugosimetric study of four polishing protocols of a microhybrid composite resin
No full textBackground: Finishing and polishing a composite restoration are fundamental phases for clinical success. Choosing the right polishing protocol for the composite type is essential. The present rugosimetric study tests on a microhybrid composite resin the efficacy of 4 polishing protocols with rubber points or abrasive pastes with or without a superficial light-curing resin.
Methods and Materials: Forty Filtek Z250 composite resin discs were prepared and divided into 4 groups of different decreasing grain polishing protocols: G1 rubber points; G2 abrasive pastes; G3 rubber points + Seal Coat Fast resin; G4 pastes + Seal Coat Fast resin. The specimens were analyzed using a rugosimeter considering linear (Ra: parallel, perpendicular, and oblique to the polishing direction) and surface (Sa) parameters. A 0,2 μm roughness value was assumed as clinically acceptable threshold. The collected data were statistically analyzed with Kruskal-Wallis and Mann-Whitney tests (C.I. 95%).
Results: The 4 groups offered roughness mean values lower than 0,2 μm; generally G4 offered the lowest mean values; a not always statistically significant trend of roughness decrease was demonstrated with pastes. A difference was found for Sa: G1 vs G4 e G2 vs G4 (p<0,005), G3 vs G4 (p<0,05); Ra parallel: G1 vs G2 e G2 vs G4 (p<0,05); Ra perpendicular: G1 vs G2 e G3 vs G4 (p<0,05), G1 vs G4 e G2 vs G4 (p<0,001); Ra oblique: G1 vs G4 e G2 vs G4 (p<0,001), G3 vs G4 (p<0,005).
Conclusions: The mean roughness values remained under the limit indicated by the literature in all groups. A decreased surface roughness of the Filtek Z250 was demonstrated by using abrasive pastes + Seal Coat Fast resin polishing protocol
Surface roughness of a microhybrid composite polished with abrasive pastes
No full textObjective: Occlusal surfaces of dental restorations should reestablish the anatomy of cusps, pits and fissures that has been lost. Since this complex area of the restoration is difficult to polish properly with rigid and semi-rigid rotary instruments, the benefits of polishing pastes have been highlighted and their use advocated. The present study aims to individuate a polishing protocol for a microhybrid composite using abrasive pastes with decreasing grit. Methods: Sixty composite discs (Filtek Z250, 3M ESPE, USA) were assigned to six experimental groups (n=10), each one established to be the sequential step of a polishing protocol based on abrasive pastes (Diamond ACI, ACII and Excel, FGM, Brazil): G1, simulated finishing with 40 μm diamond bur; G2, as G1 + 75-80 μm paste; G3, as G2 + 30-35 μm; G4, as G3 + 2-4 μm; G5a, as G4 + felt wheel; G5b, as G4 + resin coating (Seal Coat Fast, DEI Italia, Italy) and felt wheel. The profilometric superficial parameter Sa was taken into account as measure of the roughness on the treated surfaces. Non-parametric statistical analysis was used to assess differences among groups (α=0.05). Results: The registered mean Sa values ±SD expressed in μm were: G1, 0.31±0.06; G2, 0.11±0.01; G3, 0.11±0.02; G4, 0.12±0.02; G5a, 0.17±0.07; G5b, 0.09±0.03. The decrease in surface roughness among groups representing subsequent steps was statistically significant between G1 and G2 (p<0.001) and between G4 and G5b (p<0.01). Similar surface roughness was observed in groups 2 to 5a. Conclusion: Polishing pastes were effective in improving the surface smoothness of the composite after the finishing procedure. The 30-35 μm and the 2-4 μm pastes and the felt wheel alone did not influence the surface roughness obtained after the use of the 75-80 μm paste, which was already low. The resin coating yielded the smoothest surface
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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