1,720,981 research outputs found
Evaluation of confocal microfluorimetric methods for the study of lateral diffusion in model systems and oligodendroglial cell membranes
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Evaluation of confocal microfluorimetric methods for the study of lateral diffusion in model systems and oligodendroglial cell membranes
No full textnot availabl
Magnetic resonance imaging: value of diffusion-weighted imaging in differentiating benign from malignant breast lesions
No full textObjectives: Although magnetic resonance imaging (MRI) has a high sensitivity in the detection of tumours, there is still much discussion about its role in breast cancer detection. MRI is not yet routinely used to further characterize lesions in patients diagnosed with breast cancer. This study investigated the impact of preoperative MRI on the surgical treatment of women with biopsy proven breast cancer. The diagnostic value of preoperative MRI was compared with that of conventional imaging (mammography and ultrasonography), and the diffusion-weighted imaging technique was also evaluated. Study design: 40 women underwent conventional imaging and biopsy as part of the clinical workup. In addition, preoperative MRI was performed in each patient. The kinetics of contrast captation were monitored and apparent diffusion coefficients were calculated. All imaging findings were compared with the histopathologic results, which were used as the gold standard. Differences in tumour extent, as determined by ultrasonography, MRI and histopathology, were evaluated. Results: Contrast captation kinetics curves are mostly aspecific, while apparent diffusion coefficient values seem to correlate much better with tumour malignancy. MRI correlated more accurately with histopathological findings than ultrasonography and even revealed unsuspected multifocal and multicentric breast carcinoma in 20 patients (50%). The surgical plan of seven patients (18%) was changed as a result of the additional information provided by MRI. Conclusion: Diffusion-weighted imaging as a complementary tool to contrast captation kinetics and morphologic measurements may increase the specificity of MRI and help in differentiating between benign and malignant breast lesions. In addition, MRI yields more precise information than mammography and ultrasonography about the exact location, the extent, the multifocality or multicentricity of the tumour and can also detect possible additional tumours. Although MRI will never replace mammography (screening) or ultrasonography as a test for breast cancer in women with no high risk (e.g. BRCA 1 or 2 carriers), its use in a preoperative setting may allow more accurate staging of the disease, which in turn could result in a change in the treatment planning. (C) 2012 Elsevier Ireland Ltd. All rights reserved
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
Relief of Myocardial Edema in Advanced Decompensated Heart Failure is Associated with Improved Left Ventricular Systolic and Diastolic Function
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