1,721,076 research outputs found
Semi-automated Segmentation and Quantification of Mitral Annulus and Leaflets from Transesophageal 3-D Echocardiographic Images
Full text linkQuantitative characterization of mitral annulus and leaflets from transesophageal 3D echocardiography
No full textWe propose and validate a novel algorithm for the segmentation and quantification of the mitral annulus (MA) and mitral leaflets (ML) from transesophageal real-time 3D echocardiography volumes in a closed mitral valve (MV) configuration. Following initialization of 8 MA points and of the coaptation line, the MA and the anterior and posterior ML are automatically obtained in 3D. Once segmented, several morphological parameters, including local ML thickness and tenting, are obtained. Validation versus manual tracings was performed in 33 patients: 9 controls, with normal MA dimensions, 12 patients with dilative cardiomyopathy and 12 after MV repair with insertion of annuloplasty ring on the posterior MA region. MA and ML segmentations showed a high level of accuracy when compared with manual tracings, with errors of the order of the voxel size. Computed parameters were comparable with those found in literature for healthy MV. The potential clinical applicability to different MV pathologies, as well as repaired valves with implanted annular rings, was favorably tested. © 2013 CCAL
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
Two new calibration techniques of lumped-parameter mathematical models for the cardiovascular system
Full text linkCardiocirculatory mathematical models serve as valuable tools for
investigating physiological and pathological conditions of the circulatory
system. To investigate the clinical condition of an individual,
cardiocirculatory models need to be personalized by means of calibration
methods. In this study we propose a new calibration method for a
lumped-parameter cardiocirculatory model. This calibration method utilizes the
correlation matrix between parameters and model outputs to calibrate the latter
according to data. We test this calibration method and its combination with
L-BFGS-B (Limited memory Broyden - Fletcher - Goldfarb - Shanno with Bound
constraints) comparing them with the performances of L-BFGS-B alone. We show
that the correlation matrix calibration method and the combined one effectively
reduce the loss function of the associated optimization problem. In the case of
in silico generated data, we show that the two new calibration methods are
robust with respect to the initial guess of parameters and to the presence of
noise in the data. Notably, the correlation matrix calibration method achieves
the best results in estimating the parameters in the case of noisy data and it
is faster than the combined calibration method and L-BFGS-B. Finally, we
present real test case where the two new calibration methods yield results
comparable to those obtained using L-BFGS-B in terms of minimizing the loss
function and estimating the clinical data. This highlights the effectiveness of
the new calibration methods for clinical applications.Comment: 33 pages, 7 figures, submitted to International Journal for Numerical
Methods for Engineerin
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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