1,721,308 research outputs found
Analysis of a flat, dielectric-loaded, ion cyclotron, test antenna by using three electromagnetic codes
No full textThe present work compares the results coming out from the following three Ion Cyclotron antenna tools: HFSS, COMSOL Multiphysics and the TOPICA code. A simplified flat antenna geometry, working at 30 MHz, is used as benchmark. The comparison is carried out with respect to the scattering matrix and the RF potentials, i.e., the line integrals of the electric field along the flux tubes of the equilibrium magnetic field. Various operational configurations characterized by different antenna load clearance are considered. Very good agreement can be observed among the codes for all the simulated configurations in terms of scattering parameters. RF potentials also match as
regards to patterns, trends as well as absolute values
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
INFLUENZA DI DIVERSE SUPERFICI IMPLANTARI SULL'ACCUMULO DI PLACCA E IL COMPORTAMENTO DEI TESSUTI PERIIMPLANTARI. Studio clinico a 12 mesi
No full textOBIETTIVI: Valutare l’accumulo di placca e la risposta dei tessuti periimplantari a contatto con impianti con superficie sottoposta a doppia mordenzatura acida (DAE) (test) e con impianti con superficie DAE e una porzione coronale macchinata (controllo), simulando la loro esposizione nel cavo orale
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
Long-term survival of endodontically treated, maxillary anterior teeth restored with either tapered or parallel-sided glass-fiber posts and full-ceramic crown coverage
No full textObjectives: This retrospective study investigated the clinical effectiveness over up to 8 years of parallel-sided and of tapered glass-fiber posts, in combination with either hybrid composite or dual-cure composite resin core material, in endodontically treated, maxillary anterior teeth covered with full-ceramic crowns. Methods: The study population comprised 192 patients and 526 endodontically treated teeth, with various degrees of hard-tissue loss, restored by the post-and-core technique. Four groups were defined based on post shape and core build-up materials, and within each group post-and-core restorations were assigned randomly with respect to root morphology. Inclusion criteria were symptom-free endodontic therapy, root-canal treatment with a minimum apical seal of 4 mm, application of rubber dam, need for post-and-core complex because of coronal tooth loss, and tooth with at least one residual coronal wall. Survival rate of the post-and-core restorations was determined using Kaplan-Meier statistical analysis. Results: The restorations were examined clinically and radiologically; mean observation period was 5.3 years. The overall survival rate of glass-fiber post-and-core restorations was 98.5%. The survival rate for parallel-sided posts was 98.6% and for tapered posts was 96.8%. Survival rates for core build-up materials were 100% for dual-cure composite and 96.8% for hybrid light-cure composite. Conclusions: For both glass-fiber post designs and for both core build-up materials, clinical performance was satisfactory. Survival was higher for teeth retaining four and three coronal walls. (C) 2008 Elsevier Ltd. All rights reserved
Coupling and near-field simulations of ion-cyclotron antennas: Numerical validation of the perfectly matched layer technique for several density profiles
Full text linkA simplified, flat, plasma-loaded, ion-cyclotron antenna has been simulated using three different modeling approaches and a comparison of simulation outputs is presented in this paper. Several plasma profiles with different density gradients and distances between the antenna and the cutoff density have been used as benchmark for the numerical simulations, which have been run at 30 MHz by means of two tools. The one is the TOrino Polythecnic Ion-Cyclotron Antenna (TOPICA) code that has been repeatedly used and validated for this type of problems. The other tool is the finite-element method (FEM) of a commercial software, where inhomogeneous anisotropic materials can be defined and the perfectly matched layer technique can be adopted. In this tool, two models of antenna load have been implemented: an equivalent dielectric, locally matching the perpendicular propagation constant of the fast wave in the plasma, and a cold plasma model. The simulation results by such models are compared with the results by TOPICA, which relies on a 1-D inhomogeneous, hot plasma
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