1,721,316 research outputs found
Contribution of invertebrate models to aging and longevity studies
Full text linkThis paper summarizes pros and cons of the invertebrate models involved in aging and longevity. The worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster are the two models that have given the major contributions on this topic. Furthermore, we also discuss the possible contribution of recent theories on aging and inflammation to understand the complex phenotype of aged soma, from invertebrates to humans
A new theory on the common evolutionary origin of natural immunity, inflammation and stress response: The invertebrate phagocytic immunocyte as an eye-witness
No full textData in favor of the hypothesis of the common evolutionary origin of natural immunity inflammation and stress response are presented. These phenomena seem to be mediated by a common pool of molecules (POMC-derived peptides, cytokines, biogenic amines, glucocorticoids, and nitric oxide). Macrophages are able to release all the above mentioned molecules. They play a primary role in defence mechanisms. Thus, we argue that this cell can be considered the eye-witness of the common evolutionary origin of the immune and neuroendocrine systems
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
Presence of immunoreactive corticotropin-releasing hormone and cortisol molecules in invertebrate haemocytes and lower and higher vertebrate thymus
No full textCorticotropin-releasing hormone-and cortisol-like molecules are present in the haemocytes of different molluscan species and in the epithelial cells, interdigitating cells and macrophages - but not in the lymphocytes - of fish, frog, chicken and rat thymus. Taking into account the fact that other pro-opiomelanocortin-derived peptides, such as adrenocorticotropin hormone, are present in the haemocytes and thymus of the same species, these results complete the list of stress mediators present in molluscan haemocytes and further support the hypothesis that, although the prototype stress response we have demonstrated in invertebrates is concentrated in a single cell, i.e. the haemocyte, it is similar to the response seen in vertebrates. Moreover, the data presented here are compatible with the hypothesis that an evolutionary, conserved stress response can occur locally with a single organ, e.g. the thymus, in which all the main mediators of this biological response, such as corticotropin-releasing hormone, adrenocorticotropin hormone and glucocorticoids, are present. The implications of these findings for the physiology of thymus and stress response may be far reaching
The invertebrate phagocytic immunocyte: Clues to a common evolution of immune and neuroendocrine systems
No full textIn invertebrates, lower vertebrates and higher vertebrates, a common pool of highly conserved molecules appears to mediate phagocytosis, the stress response and inflammation. Here, Enzo Ottaviani and Claudio Franceschi propose an evolutionary hypothesis based on an integrated network of adaptive mechanisms that are critical for survival. The macrophage plays a pivotal role in this process
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