1,721,849 research outputs found
Existence and regularity for solutions of quasilinear degenerate elliptic systems
No full textThe existence of a solution to a quasilinear system of degenerate equations is proved, assuming that the datum has an intermediate degree of summability and that the off -diagonal coefficients have a support contained in a crossed staircase set. The support required in this paper is larger than the one assumed in a previous work
Beni pubblici e produzione di esternalità positive: le tendenze innovative nelle politiche agricole europee
No full textEvaluation of Maxillary Dentoalveolar Expansion with Clear Aligners: A Retrospective CBCT Study
Full text linkBackground/Objectives: Currently, clear aligners are preferred to conventional appliances,
especially among adult patients. However, the use of aligners for treating maxillary
constriction is still debated in the literature. Therefore, the purpose of this study was
to assess maxillary dentoalveolar expansion following clear aligner therapy in adults
using CBCT scans. Methods: The study sample encompassed 50 non-growing patients
(27 females and 23 males) aged 20 to 42 undergoing clear aligner orthodontics without
dental extractions or auxiliaries. Transverse linear distances were measured on initial
and final CBCTs and, subsequently, analysed through paired t-test and ANOVA. We
considered alveolar bone measurements and interdental widths measured at the buccal
apices and cusps from canines to second molars. Results: The buccal alveolar ridge width
showed the greatest expansion (1.01 ± 0.38 mm), followed by the palatal alveolar ridge
and maxillary alveolar bone. Statistically significant improvements were observed for all
interdental measurements. The most considerable changes occurred in the interpremolar
cusp distances, while the least changes were seen in the intermolar apex distances. At
the cusp level, the average interpremolar widths increased by 3.44 ± 0.22 mm for the first
premolars and 3.14 ± 0.27 mm for the second ones. Conclusions: Clear aligner treatment
can effectively manage a constricted maxillary arch. We found significant changes in the
maxillary alveolar bone. Both inter-apex and inter-cusp widths increased in all teeth, with the highest values in the premolars. Moreover, the increases in interdental distances at both apex and cusp levels were related to tooth position
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
Differences in volume and surface of mandibular condyles in Caucasian adult subjects with low, normal or high mandibular plane angle
No full textObject: The aim of this study was to evaluate the condylar volumes in a group of patients aged between 15 and 50 years old. They were pre-orthodontic asymptomatic patients with different facial structure (low mandibular plane angle, normal angle, high angle). The evaluation of the volume of facial structures became recently important because the volumetric value of a solid can describe, in only one number, the data on the form and surface of the object, bearing in mind also the hollow structures (nasal cavity, sinus, oral cavity). The evaluation of the volume of facial structures is today possible through the segmentation of structures within the 3D reconstructions.
Materials and methods : We examined Cone Beam data of 60 young adult caucasian subjects with different facial structures (low angle, high angle, normal angle) before they were scheduled to undergo orthodontic treatment for dental problems of overcrowding. The criteria for inclusion of patients were the absence of TMD symptoms, of tooth agenesis, of previous Ortognathic surgery, of posterior occlusal stop, and extreme brachycephalic and dolichocephalic. The cephalometric analysis on Cone Beam data was performed with Dolphin 3D on DICOM files. The calculation of volume and condylar surface was done with the software Mimics, through the technique of segmentation.
Results: By dividing the sample into three groups (high angle, normal angle, low angle) we highlighted statistically significant differences in volumes and areas of right and left mandibular condyles within the types of facial divergence. The low angle subjects showed a significantly greater volume and condylar surface than the other two groups. In the three groups, the values of the areas showed a standard deviation and a range higher than the other 2 groups.
Discussion: The observed differences could be related to different muscle tone of the masticatory muscles. in another study F. Festa et al (2006) observed how the sEMG activity of the masseter, the anterior temporal, and of the upper trapezius and posterior cervical at mandibular rest position was higher in low angle subjects as compared to high angle and normal angle subjects. This higher sEMG activity may be responable for the volume of the condyle.
Conclusions: There is evidence of an association between volume and mandibular divergence. For all groups, values that indicate the condylar surface showed inter-individual variation higher than the values indicating the condylar volume and this result could be associated with the presence - on the condylar surface - of microscopic anfractuosity (small pits, furrows, various irregularities) that are able to influence the measurements of the condylar surface, but are not able to significantly influence the measurements of the condylar volum
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
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