1,720,962 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
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
Weight is an independent predictor of vascular injury in healthy volunteers with aspartate allele.
No full textBACKGROUND: Endothelial dysfunction and carotid intima-media thickeness (IMT) are currently considered key early events in atherogenesis and markers of arterial damage. We investigated whether endothelial nitric oxide synthase (eNOS) glutamate (Glu)298-aspartate (Asp) polymorphism may influence the vascular response to weight, as measured by BMI, in young, healthy individuals. METHODS: One hundred young (30.6 ± 5.9 years) healthy individuals, without concomitant traditional cardiovascular risk factors took part in the study. Brachial artery endothelial function was assessed by vascular response to reactive hyperemia [flow-mediated dilation (FMD) and sublingual nitroglycerin (GTN)-mediated dilation] using high-resolution ultrasound. Carotid IMT was also measured. RESULTS: Participants were grouped as Glu-homozygotes (n = 38) and Asp-carriers (n = 62). On univariate analysis, a higher response to GTN was associated with lower brachial baseline diameter (P < 0.001) and increasing value of high-density lipoprotein cholesterol (P = 0.04) in Asp-carriers, but not in Glu-homozygotes. Higher FMD correlated with lower brachial baseline diameter (P < 0.001), BMI (P = 0.03) and SBP (P = 0.03) in the Asp-carriers, but not in Glu-homozygotes. Higher IMT showed a similar Asp-genotype-dependent association with higher BMI (P = 0.001), SBP (P = 0.006) and DBP (P = 0.001). In individuals with Asp-alleles, the multivariate analysis showed that BMI was the only independent predictor of IMT. CONCLUSION: Weight is independently associated with impaired arterial structure in healthy and genetically predisposed young individuals. The allelic variation (Asp298) of the eNOS gene polymorphism makes individuals vulnerable to the impact of weight on the development of atherosclerosi
Prosurvival communication between endothelial cells and mesenchymal stem cells through exosomes containing HIF1-alpha
No full textThe transcription factor hypoxia-inducible factor 1 alpha (HIF1-a) is a downstream regulator of hypoxia response and neovascularization in adult myocardium. As exosomes mediate cell-cell communication in many stress responses, we investigated the release of exosomes containing HIF1-a (HIF1a-exo) by arterial endothelial cells (pAOECs) and mesenchymal stem cells (pMSCs), which characterize the myocardial angiogenesis. We also evaluated the transport of HIF1a-exo between the two cell lines under normoxia and hypoxia. Up to 72h of normoxic monocolture, the release of HIF1a-exo by pAOECs did not change compared to baseline, yet HIF1-a expression increased by 80±5% (p<0.001); although, HIF1-a espression and HIF1a-exo secretion by pMSCs were lower than pAOECs, but higher at 72h than baseline (p<0.05). At 72h of normoxic co-culture, the level of HIF1α-exo wa s similar to single-pAOECs culture and increased by 175±11% compared to baseline (P<0.001), even if HIF1-α level in pAOECs was reduced by 40±7% than pMSCs (p<0.05). The number of both cell lines was significantly higher in co-culture compared to each monocolture. At 72h of hypoxic co-colture, the number of pAOECs and pMSCs was respectively reduced by 44±5% (p<0.001) and 32±2% (p<0.001). Even if HIF1-a expression was higher in co-cultered pMSCs, the release of HIF1a-exo was lower than hypoxic monoculture and similar to normoxia. In conclusion, the cross talk between pAOECs and pMSCs through HIF1a-exo is attenuated under hypoxia
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