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Aging, cardiac hypertrophy and ischemic cardiomyopathy do not affect the proportion of mononucleated and multinucleated myocytes in the human heart
No full textGender differences and aging: effects on the human heart
No full textOBJECTIVES: This study investigated the changes in myocyte size and number in the
left and right ventricles that occur with aging in the female and male heart.
BACKGROUND: Differences in life span between women and men may be related to a
better preservation of myocardial structure in the female heart with aging. On
this basis, the hypothesis was advanced that the aging process has a different
impact on the integrity of the myocardium in the two genders.
METHODS: Morphometric methodologies were applied to analyze the changes in number
and size of ventricular myocytes in the hearts of 53 women and 53 men. The
changes in mononucleated and binucleated myocytes with age were determined in
enzymatically dissociated cells. The age interval examined varied from 17 to 95
years.
RESULTS: Aging was associated with a preservation of ventricular myocardial mass,
aggregate number of mononucleated and binucleated myocytes, average cell diameter
and volume in the female heart. In contrast, nearly 1 g/year of myocardium was
lost in the male heart, and this phenomenon accounted for the loss of
approximately 64 million cells. This detrimental effect involved the left and
right sides of the heart. In the remaining cells, myocyte cell volume increased
at a rate of 158 microns3/year in the left and 167 microns3/year in the right
ventricle.
CONCLUSIONS: Aging does not lead to myocyte cell loss and myocyte cellular
reactive hypertrophy in women, indicating that gender differences may play a
significant role in the detrimental effects of the aging process on the hear
Proliferating cell nuclear antigen (PCNA), DNA synthesis and mitosis in myocytes following cardiac transplantation in man
No full textAcute myocardial infarction in humans is associated with activation of programmed myocyte cell death in the surviving portion of the heart.
No full textGoing 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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