1,721,014 research outputs found
Relevance of hepatic estrogen receptor alpha in liver metabolic adaptation during pregnancy
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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
Imaging of estrogen receptor transcriptional activity
No full textMolecular imaging, i.e. the non-invasive imaging of target macromolecules and biological processes in living organisms, is providing a novel and powerful technology for the progress of biomedical research by facilitating the study of physio-pathological events in living organisms and by implementing the path towards novel drugs discovery. The ERE-Luc transgenic mouse line generated in 2001 in our laboratory is the first prototype of reporter animals, in which the firefly luciferase reporter gene is expressed in all tissues and regulated by the estrogen receptors (ERs) through an estrogen-responsive promoter. The luciferase activity is quantitatively detectable by evaluating photon emission through a charge-coupled device (CCD) camera and converting optical into digital imaging. The use of in vivo imaging of the ERE-Luc mice provided us with the opportunity to study the physiological fluctuations of ERs action in mice during the estrous cycle and to demonstrate that the state of ER transcriptional activity is regulated by circulating estradiol only in reproductive organs and liver, while in organs that are not linked with reproductive functions ERs are activated by signals other than estradiol through a mechanism known as “unliganded activation”. It is known that aging is associated with changes in physiological parameters, such as oxidative stress or immune senescence, that might influence ER transcriptional activity. Similarly, menopausal transition is linked with physiopathological alterations that are thought to be mediated by loss of estrogen signalling. Therefore, the principle objective of the present work is to study ER transcriptional activity at the menopause transition and during aging. We assayed bioluminescence imaging in non reproductive organs of ERE-Luc mice at different ages (3, 6, 12, 18 and 22 months-old) and after ovary removal, the most reliable model of menopause. Briefly, after systemic injection of the luciferase substrate, luciferine, we quantified luciferase activity in vivo by bioluminescence imaging and in vitro by an enzymatic assay on tissue extracts. Data are validated by measuring the expression of estrogen target genes, such as progesterone receptor. The results of these experiments will be discussed. Altogether, our study shows the extent to which ER transcriptional activity changes from 6 up to 22 months of age and after ovariectomy, providing insight in the relevance of unliganded activation of ERs activity in the onset of disorders associated with aging and menopause
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
17beta-estradiol inhibits inflammatory gene expression by controlling NF-kB intracellular localization
No full textEstrogen is an immunoregulatory agent, in that hormone deprivation increases while 17ß-estradiol (E2) administration blocks the inflammatory response; however, the underlying mechanism is still unknown. The transcription factor p65/relA, a member of the nuclear factor kB (NF-kB) family, plays a major role in inflammation and drives the expression of proinflammatory mediators. Here we report a novel mechanism of action of E2 in inflammation. We observe that in macrophages E2 blocks lipopolysaccharide-induced DNA binding and transcriptional activity of p65 by preventing its nuclear translocation. This effect is selectively activated in macrophages to prevent p65 activation by inflammatory agents and extends to other members of the NF-kB family, including c-Rel and p50. We observe that E2 activates a rapid and persistent response that involves the activation of phosphatidylinositol 3-kinase, without requiring de novo protein synthesis or modifying Ik-Ba degradation and mitogen-activated protein kinase activation. Using a time course experiment and the microtubule-disrupting agent nocodazole, we observe that the hormone inhibits p65 intracellular transport to the nucleus. This activity is selectively mediated by estrogen receptor alpha (ERa) and not ERb and is not shared by conventional anti-inflammatory drugs. These results unravel a novel and unique mechanism for E2 anti-inflammatory activity, which may be useful for identifying more selective ligands for the prevention of the inflammatory response
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