1,720,967 research outputs found
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
CARDIAC STEM CELLS: A NEW POTENTIAL TOOL FOR CARDIAC REPAIR?
No full textBackground: The current therapy for myocardial infarction (MI) is not adequate enough, since mortality after MI remains very high. Cardac repair by injection of stem cells is a promising therapy. Previously, several clinical studies using bone marrow stem cells were undertaken to explore the possibilities of stem cell therapy. Meanwhile, more evidence emerges that cardiac stem cells (CSCs) are present in the adult human heart. These CSCs are claimed to be actual stem cells residing in the heart and not just bone marrow stem cells mobilized to the heart. Therefore, CSCs are probably better suited for cardiac repair, since they are most likely already "pre-programmed" to become cardiomyocytes. Aim. To support this hypothesis, the aim of our study was to isolate human CSCs and compare them phenotypically and functionally with human mesenchymal stem cells (MSCs). Design and methods. For the isolation of CSCs the two main methods described by Messina et al. and by
Anversa et al. were followed. Messina et al. defines CSCs as cardiosphere
derived cells (CDCs), which can be obtained by culturing phasebright
cells that appear after two weeks in a culture of cardiac explants.
On the contrary, Anversa et al. consider c-kit+ cells isolated from cell outgrowth
from a cardiac explant as CSCs. Upon isolation, CDCs, c-kit+
cells and MSCs appeared to be morphologically very similar in culture.
Therefore, different panels of antibodies were used to phenotypically
characterize these three cell types. Results. CDCs, c-kit+ cells and MSCs
were found to be positive for CD13, CD29, CD44, CD55, CD90,
CD49c, CD73, CD105 but negative for CD34, CD45 and CD133. The
main difference between cells isolated from heart tissue and MSCs was that only MSCs stained positive for CD140b. For the functional analysis, cells were subjected to a stem cell differentiation assay. While MSCs could easily differentiate to adipocytes, osteocytes, and chondrocytes, CDSs could not. In addition, the possibility of differentiation into cardiomyocytes was examined. Therefore, cells of all three populations
were cultured in differentiation medium containing 2% FCS and 5-aza,
DMSO or TGF-b respectively. To investigate differentiation, cells were
harvested and analyzed for expression of cardiomyocyte specific genes
by RT-PCR. Preliminary results from these monocultures indicated that cells isolated from heart tissue had more potential to differentiate into cardiomyocytes than MSCs, because the former cell populations expressed cardiac troponin T and b-actinin in these conditions while the MSCs did not. Conclusions. These results indeed suggest that there is a phenotypical and functional difference between CSCs and MSCs, but further investigations have to be performed to show that these CSCs are able to differentiate into cardiomyocytes in vitro and in vivo
CARDIAC STEM CELLS: A NEW POTENTIAL TOOL FOR CARDIAC REPAIR?
No full textBackground: The current therapy for myocardial infarction (MI) is not adequate enough, since mortality after MI remains very high. Cardac repair by injection of stem cells is a promising therapy. Previously, several clinical studies using bone marrow stem cells were undertaken to explore the possibilities of stem cell therapy. Meanwhile, more evidence emerges that cardiac stem cells (CSCs) are present in the adult human heart. These CSCs are claimed to be actual stem cells residing in the heart and not just bone marrow stem cells mobilized to the heart. Therefore, CSCs are probably better suited for cardiac repair, since they are most likely already "pre-programmed" to become cardiomyocytes. Aim. To support this hypothesis, the aim of our study was to isolate human CSCs and compare them phenotypically and functionally with human mesenchymal stem cells (MSCs). Design and methods. For the isolation of CSCs the two main methods described by Messina et al. and by
Anversa et al. were followed. Messina et al. defines CSCs as cardiosphere
derived cells (CDCs), which can be obtained by culturing phasebright
cells that appear after two weeks in a culture of cardiac explants.
On the contrary, Anversa et al. consider c-kit+ cells isolated from cell outgrowth
from a cardiac explant as CSCs. Upon isolation, CDCs, c-kit+
cells and MSCs appeared to be morphologically very similar in culture.
Therefore, different panels of antibodies were used to phenotypically
characterize these three cell types. Results. CDCs, c-kit+ cells and MSCs
were found to be positive for CD13, CD29, CD44, CD55, CD90,
CD49c, CD73, CD105 but negative for CD34, CD45 and CD133. The
main difference between cells isolated from heart tissue and MSCs was that only MSCs stained positive for CD140b. For the functional analysis, cells were subjected to a stem cell differentiation assay. While MSCs could easily differentiate to adipocytes, osteocytes, and chondrocytes, CDSs could not. In addition, the possibility of differentiation into cardiomyocytes was examined. Therefore, cells of all three populations
were cultured in differentiation medium containing 2% FCS and 5-aza,
DMSO or TGF-b respectively. To investigate differentiation, cells were
harvested and analyzed for expression of cardiomyocyte specific genes
by RT-PCR. Preliminary results from these monocultures indicated that cells isolated from heart tissue had more potential to differentiate into cardiomyocytes than MSCs, because the former cell populations expressed cardiac troponin T and b-actinin in these conditions while the MSCs did not. Conclusions. These results indeed suggest that there is a phenotypical and functional difference between CSCs and MSCs, but further investigations have to be performed to show that these CSCs are able to differentiate into cardiomyocytes in vitro and in vivo
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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