1,720,969 research outputs found
Study on the effects of the acoustic scattering on the impulse response in a semi-anechoic room
No full textThe complex sound field in performance spaces, characterized by multiple sound reflections from various surfaces with different absorptive and diffusive characteristics, makes it difficult to deduce the effect of the single interior surface on the room impulse response. In order to obtain more knowledge on this topic, laboratory experiments were performed in a semi-anechoic room. Three different conditions were studied by monaural and binaural room impulse response measurements. Three types of surfaces with different absorptive and diffusive characteristics (flat surface and two differently absorbing concrete blocks with the same geometrical pattern) were placed on the floor during the experiments. The measurements were performed at the same distance from the surface sample at three different distances from the source position. Moreover, for each microphone position eight different orientations of the artificial head were considered. The monaural and binaural impulse responses have been analyzed by comparing the different surface configurations and different orientations of the artificial head. Five objective parameters have been used in this analysis: the ratio between the direct and the reflected sound (DRR), the Time Delay Gap (TDG), the Inter-aural Cross Correlation (IACC), the Inter-aural Time Difference (ITD) and the Inter-aural Level Difference (ILD
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
Orthodontic treatment and third molars development: longitudinal study on radiographs
No full textOBJECTIVES The purpose of this study was to evaluate the effects of first premolar extraction on third molar angulation during fixed orthodontic treatment. MATERIALS AND METHODS The sample of this study included pre-treatment and post-treatment orthopantomographs (OPG) of 40 patients, 17 males and 23 women (106 third molars), treated by fixed orthodontic appliances at the Department of Orthodontics, Sapienza University, Rome. All individuals had both first and second mandibular molars present at all stages and initial malocclusion. Records - including dental study models, lateral cephalograms, panoramic radiographs, and facial photographs - were collected before, during and after orthodontic treatment. The sample of patients was divided into two sub-groups: - - a group of 20 patients who have received orthodontic treatment without premolar extractions; - a second group of 20 patients treated with premolar extractions. Pre-treatment mean age of the extraction group was 13.17 years (±1.54), and 12.23 years (±1.45) for the non extraction group. The mean duration of treatment was 5.17 years (±1.12) in the extraction group and 4.53 years (±1.00) in the non extraction group. The inclusion criteria in the study group were the following: - existence of longitudinal series of orthopantomograms (OPG) pre-treatment (T1), during treatment (T2) and post-treatment (T3); - the crowns of the third molar formed at the beginning of the orthodontic treatment; - second premolars and second molars fully erupted into the mouth; - patients treated with fixed orthodontic appliances (maxillary and mandibular). Both pre- and post-treatment radiographs were evaluated by using the following techniques: - tracing the images of the teeth on the acetate paper; - angular measurements of reference lines (the anterior angle formed between the long axis of the third molar and the long axis of the second molar [M3-M2] and the anterior angle between the long axis of the third molar and the occlusal plane [M3-OP]). The post-treatment values were subtracted from pre-treatment values to calculate the degree of changes in the angulation of third molar relative to the occlusal plane and second molars. The data were analysed by Student’s t-test. A p value ≤0.05 was considered as significant. RESULTS AND CONCLUSIONS The data show that the uprighting of the wisdom tooth long axis is more important in patients treated with premolar extractions. The angle between the maxillary third and the second molar has decreased, the third molar axis has uprighted, but only in patients treated with premolar extractions. In the group of patients treated without extractions, the results showed increased values of this angle, pointing an unfavourable change in the wisdom tooth angulation. In both groups of patients, the changes in maxillary third molars angulation resulting from orthodontic treatment showed statistically significant values. CLINICAL SIGNIFICANCE The ability to early predict the future evolution of the developing third molars can be of great help in planning orthodontic, surgical and prosthetic treatment. The extraction of first premolars during orthodontic treatment significantly improved the angulation of third molars toward uprighting. However, an improvement in angulation does not necessarily mean that third molars will erupt in good position. Therefore it may be prudent for orthodontists to inform their patients that premolar extractions may not prevent the need for third molar extractions in future
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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