1,733,836 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
Electron spectroscopic imaging of secretory granules in human eccrine sweat glands
No full textA study of human eccrine sweat glands by electron spectroscopic imaging has been performed. A high nitrogen content in secretory granules of the dark mucous cells has been found while mucous cells in the digestive or respiratory systems did not contain nitrogen detectable in our experimental conditions. High concentrations of nitrogen were found in zymogenic granules and in the core of the granules in the eosinophilic leucocytes. Our findings seem to suggest that the granules of the dark secretory cells are composed not only of mucoid substances but contain also high concentrations of proteins. The descriptive term "granulated cells" seems to be more correct than "mucous cells" to indicate these elements
Ultrastructure of pituitary folliculo-stellate cells of lactating rat during treatment with 2-bromo-alpha-ergocriptine
No full textFolliculo-stellate cells of adenohypophysis were studied by transmission electron microscopy in lactating rats during treatment with the dopaminergic agonist 2-bromo-alpha-ergocriptine. Folliculo-stellate cells showed marked activation in control lactating rats, were unaffected by a single injection of the drug (3 mg/kg), regressed to the morphology of those found in non-lactating animals upon 6 days of drug treatment (1 mg/kg/die) both in presence and in absence of the suckling stimulus. However, morphometric analysis showed a proportion of folliculo-stellate cells in the gland which was similar in the four experimental groups (range: 11.3-13.5%), despite the increasing reduction of prolactin cells (55, 44, 32, 30%). In chronically treated animals to which suckling had been denied, extruding and degenerating prolactin cells were found, as well as extracellular material in non follicular spaces; the latter were lined by both folliculo-stellate and endocrine cells. These data suggest a dual reactivity of folliculo-stellate cells in the adenohypophysis according to the functional status of the gland
Brown adipose tissue: a scanning electron microscopic study of tissue and cultured adipocytes
No full textThe ultrastructure of rat brown adipose tissue (BAT) and of adipocytes cultured from BAT were studied by scanning electron microscopy (SEM). Brown adipocytes in the intact tissue were arranged in lobules with bundles of collagen among them; within each lobule 20- to 40-microns-large adipocytes were packed together. Fibers of reticular collagen enveloped each adipocyte and also connected each cell to vessels and nerves. At the adipocyte surface rounded protrusions were present, which corresponded to the BAT-typical multivacuolar lipid depot. Gradual digestion of the stroma with collagenase disclosed a more delicate, felt-like cover surrounding each adipocyte, probably representing the external lamina of the cell. Complete digestion of the stroma showed a smooth plasmalemma with occasional roundish blebs which varied in size. Cultured (24 h) brown adipocytes from the stromal-vascular fraction of BAT were elongated or polygonal in shape, with a flattened, central nucleus and a number of spherical cytoplasmatic inclusions which have the same dimension and location as lipid droplets. These inclusions were arranged either at cellular poles or around the nucleus; this suggests that brown adipocytes with mature features were present in the culture. Pictures suggesting the detachment of lipid droplets from the cell body were also visible. Lipid droplet extrusion could be a complementary mechanism which might explain the rapid delipidation of brown adipocytes in culture
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
Localization of leptin receptor splice variants in mouse peripheral tissues by immunohistochemistry.
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