1,721,140 research outputs found
Cell Therapy for Cardiac Regeneration after Myocardial Infarct: Which Cell is the Best?
No full textIn the last decade several attempts have been made to achieve the goal of cardiac regeneration after myocardial infarction. To date, two cell types have completed phase-III clinical trials: Skeletal Myoblasts and Bone-Marrow Mononuclear Cells (BM-MNCs). In the first case, all benefits have been limited by an increased risk of arrhythmia. In the case of BM-cells, most studies showed a significant, although limited, advantage in the cell-treated group. This may be due to the choice of the wrong BM cell type: other candidates would be e.g. CD34(+) HSCs, or non-hematopoietic Mesenchymal Stem Cells. After positive results from the experimental studies, phase I/II clinical trials are currently on-going for both. Ideally, the best cell to use to regenerate the heart would be a precursor of all cardiac lineages; until the isolation and expansion of Cardiac Stem Cells (CSCs), such a cell was thought to exist only during embryogenesis. Using CSCs researchers managed to generate electrically-coupled contractile tissue within the infarct of animal models. Still, some doubts persist over the possibility to translate such results in real-life patients. Another approach, therefore, involves the use of induced Pluripotent Stem Cells (iPS) obtained from fibroblasts after genetic reprogramming. This new type of cell would combine the pluripotency of embryonal stem cells with the advantages of an autologous use. Nevertheless, iPS cells form teratomas, and their effective differentiation in vivo is largely unknown. This review will critically compare the data from the Literature concerning cell therapy after myocardial infarction. Can we name the best cell
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
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