1,720,955 research outputs found
Cyclic fatigue of instruments for endodontic glide path.
No full textEndodontic glide path is the creation of a smooth patency from canal orifice to apex, which can be performed manually or with small tapered NiTi rotary instruments. The use of stainless steel (SS) hand K-files inserted in a reciprocating handpiece can be a possible alternative to create a mechanical glide path. The aim of this study was to compare the cyclic fatigue resistance between SS K-files used in a reciprocating motion and NiTi rotary instruments in artificial curved canals. Ten SS size 15 K-files used with the M4 handpiece (SybronEndo, Glendora, CA, USA) and ten PathFiles (Maillefer-Dentsply, Ballaigues, CH, Switzerland) NiTi rotary instruments size 16, 0.02 taper were tested for resistance to cyclic fatigue. The time to fracture inside an artificial curved canal was recorded for each instrument. Data were analyzed by one-way ANOVA and Tukey HSD test. Mean time (and SD) to failure was 464 s (±40.4) for the Group PF (NiTi rotary PathFile), and 1049 s (±24.8) for the Group M4 (SS K-files reciprocating) with a statistically significant difference between the two groups (p = 0.033). The SS 15 K-files used with the M4 handpiece showed a significant greater resistance to cyclic fatigue when compared to the NiTi rotary PathFiles. Therefore, the use of small size SS files in a reciprocating motion might be a rational choice for the creation of a mechanical endodontic glide path in curved root canals. © 2013 The Society of The Nippon Dental University
Mechanical resistance of carbon and stainless steel hand instruments used in a reciprocating handpiece
Full text linkThe manual files are still widely used for initial canal negotiation prior the use of nickel-titani-um shaping instruments, to determine working length and to verify patency. A mechanical glide path can be performed using manual files with handpieces, such as M4 Handpiece (SybronEndo, USA) that allows a 30°/30° reciprocating motion. The Pathfinders (SybronEndo, USA) are hand files
designed to negotiate complex canals, made from stainless steel (SS) or carbon steel (CS) alloys. The aim of this in vitro study was to compare cyclic fatigue resistance of these two different types of manual Pathfinder instruments used in a M4 reciprocating handpiece in double curved
artificial canals. Manual instruments designed for glide path (size #9 ISO .02 taper) made from different alloys were selected: Group SS - stainless steel Pathfinders (Sybron Endo) and Group CS - carbon steel Pathfinders size K2 (Sybron Endo). Ten instruments of each group were tested for resistance to cyclic fatigue with a reciprocating M4 handpiece inside an artificial S-shaped canal; the time to fracture was recorded for each file and data were statistically analyzed (ANOVA). Mean values (and SD) were 527 (± 89) seconds for the CS instruments and 548 (± 104) seconds for the SS files. No significant differences were observed between groups (p=0,062). According to the results, both carbon and stainless steel instruments presented similar fatigue resistance when used with M4 reciprocating handpiece in double curved canals
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
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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