1,720,954 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
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
Supplementation of creatine and ribose prevents apoptosis and right ventricle hypertrophy in hypoxic hearts
No full textBackground/Aims. The simultaneous supplementation of creatine and D-ribose has been shown to reduce apoptosis in vitro in non-irreversibly injured cultured ischemic cardiomyocytes through down-regulation of the signaling mechanisms governing adenosine monophosphate-activated protein kinase (AMPK) and protein kinase B (Akt). Here, we test the hypothesis that an analogous mechanism exists in vivo when the challenge is chronic exposure to hypoxia.
Methods. Five week-old mice were exposed to an atmosphere containing 10% O2 for 10 days. Mice were gavaged daily with vehicle, creatine, D-ribose or creatine + D-ribose. After sacrifice, myocardial and pulmonary tissue were harvested for structural and biochemical analyses.
Results. Hypoxia induced right ventricle hypertrophy and left ventricle apoptosis. Both phenotypes were slightly reduced by either creatine or D-ribose, whereas the simultaneous administration of creatine + D-ribose almost completely reversed the effects of hypoxia. Furthermore, creatine + D-ribose diminished the hypoxia-induced increases in the activity of AMPK, Akt and JNK, but not of ERK. Finally, the hypoxia-induced pulmonary overexpression of endothelin-1 mRNA was markedly reduced by creatine + D-ribose.
Conclusions. The simultaneous administration of creatine + D-ribose confers additional cardiovascular protection with respect to that observed with either creatine or D-ribose. The mechanism stems from the AMPK and Akt signaling pathways. These findings may form the basis of a paradigm to re-energize non-irreversibly damaged cardiomyocytes, counteracting injury by triggering specific signaling pathways
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
IN VIVO SUPPLEMENTATION OF CREATINE AND RIBOSE PRESERVES HYPOXIC HEARTS FROM APOPTOSIS AND RIGHT VENTRICLE HYPERTROPHY.
No full textIt was previously found that H9c2 cardiomyocytes exposed to 24-h ischemia (1% O2 with glucose deprivation), were rescued by administration of 2.5 mM creatine + 5 mM D-ribose, while creatine or D-ribose alone were ineffective (1). These findings correlated with up-regulation of protein kinase B (Akt) phosphorylation. Creatine+D-ribose also blunted adenosine monophosphate-activated protein kinase (AMPK) and down-regulated apoptosis by reducing caspase-3 activation and poly (ADP-ribose) polymerase cleavage. In order to test the existence of an analogous mechanism in an in vivo context, five week-old mice were exposed to an atmosphere containing 10% O2 for 10 days, sacrificed and myocardial and pulmonary tissue harvested for structural and biochemical analyses. Mice were gavaged daily with vehicle, creatine, D-ribose or both.
Results showed that hypoxia induced marked right ventricle hypertrophy and left ventricle apoptosis. Both phenotypes were slightly reduced by the administration of either creatine or D-ribose, whereas the simultaneous administration almost completely reverted the effects of hypoxia. Furthermore, creatine+D-ribose contributed to blunt the increases in the activity of AMPK, Akt and JNK, but not of ERK, caused by hypoxia.
The increase in AMPK during hypoxia is an expected finding secondary to inadequate O2 supply with respect to needs. AMPK is probably upstream of Akt activation; in turn, Akt exerts pro-survival activities, however, by modulating the PI3-kinase pathway, Akt regulates cardiomyocyte size, thus inducing physiological cardiac hypertrophy (2). In addition, the development of right ventricle hypertrophy was found to be associated to left ventricle apoptosis (3), as reported here.
During hypoxia, pulmonary hypertension, causing pressure overload, contributes to right ventricle hypertrophy. We show here that the mRNA expression of endothelin-1, a short-lived peptide responsible for the pulmonary and heart disease (4), is increased by hypoxia. The administration of creatine+D-ribose led to reduction of the hypoxia-induced pulmonary overexpression of endothelin-1 mRNA.
Whereas creatine improves bioenergetics by recycling ADP into ATP via its shuttle property (5), ribose protects ischemic hearts by replenishing building blocks for ATP synthesis (6). By re-energization of not irreversibly-damaged myocardial cells. creatine+ribose appear to counteract myocardial injury by blunting the pathways originated from AMPK and Akt activation. This may constitute a useful therapeutic approach in several human diseases that involve systemic hypoxia, as for example chronic pulmonary obstructive diseases, heart failure as well as various forms of anemia.
References:
1- Caretti A et al, Cell Physiol Biochem.(2010), 26:831-838.
2- Rigor DL et al, Am J Physiol Heart Circ Physiol. (2009);296:H566-72.
3- Kitahori K et al, Circ Heart Fail. (2009);2:599-607.
4- Karmouty-Quintana H et al, FASEB J. (2012); 26:2546-2557.
5- Kammermeier H. J Mol Cell Cardiol. (1987);19:115-118.
6- Smolenski RT et al,. J Mol Cell Cardiol. (1998);30:673-683
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