1,721,057 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
Disruption of Prolyl hydroxylase domain protein-2 (PHD2) activity impairs TGFβ-dependent sphingolipid metabolism in murine placenta
No full textObjectives: Impairment of O2-dependent TGFβ3 signaling characterizes placental pathologies such as preeclampsia and IUGR and causes altered sphingolipid metabolism leading to increased trophoblast cell death. Under normoxic condition, degradation of the alpha subunit of hypoxia-inducible factor (HIF1A), a regulator of oxygen homeostasis, is tightly controlled by prolyl hydroxylase enzymes (PHD1-3). Ample evidence indicates that PHD2 is the key hydroxylase involved in regulating HIF1A stability in the human placenta. Our objective was to characterize the biological relevance of the O2/TGFβ3 axis in controlling sphingolipid metabolism in the murine placenta.
Methods: We generated a pharmacological hypoxic mouse model by inhibiting PHD2 activity using FG-4592, a small-molecule PHD inhibitor. Pregnant mice injected daily between E7.5 and E13.5 with FG-4592 (0.5 mg/kg) were sacrificed at E13.5. Control mice were injected with an equivalent volume of DMSO. Placentae were collected and processed for protein and sphingolipidomic analyses using immunohistochemistry, Western Blotting and liquid chromatography linked to tandem mass spectrometry (LC-MS/MS), respectively.
Results: PHD2 inhibition increased placental HIF1A, decreased its hydroxylation at the proline P564 residue, and stimulated TGFβ signaling. Administration of FG-4592 resulted in reduced placental and pup weights. Striking placental morphological defects including compaction of labyrinth zone and reduced vascularization were found. In addition, PHD2 inhibition resulted in decreased levels of sphingolipid regulatory enzymes, acid ceramidase (ASAH1) and sphingosine kinase (SPHK1), and this associated with elevated ceramide content as well as increased autophagy markers.
Conclusion: These results highlight the importance of the O2/TGFβ axis on murine placental development and function. A simulated condition of hypoxia with FG-4592 triggers TGFβ signaling, thereby impacting on sphingolipid metabolism and affecting placental cell homeostasis
Disruption of BMP9 signalling contributes to altered acid ceramidase expression and processing in preeclampsia
No full textSphingolipids are critical bioactive mediators of cellular events. Ceramide (CER) is central to sphingolipid metabolism and its levels are kept in balance via the action of key regulatory enzymes that function by modulating its synthesis and breakdown in a variety of patho-physiological conditions. In particular, lysosomal acid ceramidase (ASAH1) is responsible for hydrolyzing CER into sphingosine (SPH). We have recently reported that altered sphingolipid metabolism in preeclampsia and IUGR, is in part due to impaired TGFß signaling. Bone morphogenetic protein 9 is a member of the TGFß superfamily that functions as a high affinity ligand for the Activin Receptor-like Kinase 1(ALK1) thereby activating R-SMAD1 signalling. Herein, we investigated the role of BMP9 in regulating ASAH1 expression in physiological and pathological conditions. Human choriocarcinoma JEG3 cells were treated with BMP9 (5–10 ng/ml) or control vehicle and examined ASAH1 protein expression by Western Blotting. Exposure of JEG3 cells to BMP9 resulted in increased ASAH1 protein expression. Inhibition of ALK1 signalling using the ALK1 inhibitor Dorsomorphin reversed the BMP9 stimulatory effect and led to an accumulation of inactive ASAH1 precursors. Immunoprecipitation of ASAH1 followed by immunoblotting with concanavalin A (identifies N-glycans) revealed decreased ASAH1 glycosylation following dorsomorphin treatment indicating an ALK1 signalling dependent regulation of ASAH1 maturation. Immunofluorescence analysis showed that dorsomorphin treatment resulted in co-localization of ASAH1with the endoplasmic reticulum marker (ER) calreticulin, in line with reduced glycosylation and trafficking of ASAH1 from the ER to the lysosomes. Of clinical relevance, BMP9, ALK1 and pophorylated SMAD1 protein expression levels were markedly decreased in preeclamptic placentae relative to age-matched controls. Our data implicates a novel role for BMP9 signaling via ALK1 in regulating ASAH1 expression, processing and trafficking in the human placenta. Disruption of this signalling pathway may in part contribute to altered sphingolipid metabolism found in preeclampsia. (Supported by CIHR
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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