1,721,236 research outputs found

    Management of aortic stenosis in pregnancy

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    CITATION: Pecoraro, A. J. K. 2014. Management of aortic stenosis in pregnancy. SA Heart, 11(2):76-79, doi:10.24170/11-2-1759.The original publication is available at http://www.journals.ac.za/index.php/SAHJAortic stenosis in pregnancy is most commonly related to congenital or bicuspid aortic stenosis, which is associated with an aortopathy and ascending aortic dilatation. The management of AS in pregnancy is based on a few key principles. First and foremost the accurate assessment of the patient’s symptoms and confirmation, via echocardiography, of the degree of AS is of the utmost importance. Exercise testing is a very handy adjunct to quantify symptoms. Based on these findings, an informed process of discussion between the patient and a multidisciplinary team will lead to the correct management. As a general rule, patients who are truly asymptomatic with normal left ventricular systolic function and normal aortic root are able to tolerate pregnancy with a low maternal and fetal risk.http://www.journals.ac.za/index.php/SAHJ/article/view/1759Publisher's versio

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    First-Principles Study of Na Intercalation and Diffusion Mechanisms at 2D MoS2/Graphene Interfaces

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    Na-ion batteries (NIBs) are emerging as promising energy storage devices for large-scale applications. Great research efforts are devoted to design new effective NIB electrode materials, especially for the anode side. A hybrid 2D heterojunction with graphene and MoS2 has been recently proposed for this purpose: while MoS2 has shown good reversible capacity as a NIB anode, graphene is expected to improve conductivity and resistance to mechanical stress upon cycling. The most relevant processes for the anode are the intercalation and diffusion of the large Na ion, whose complex mechanisms are determined by the structural and electronic features of the MoS2/graphene interface. Understanding these processes and mechanisms is crucial for developing new nanoscale anodes for NIBs with high performances. To this end, here we report a state-of-the-art DFT study to address (a) the structural and electronic properties of heterointerfaces between the MoS2 monolayers and graphene, (b) the most convenient insertion sites for Na, and (c) the possible diffusion paths along the interface and the corresponding energy barrier heights. We considered two MoS2 polymorphs: 1T and 3R. Our results show that 1T-MoS2 interacts more strongly with graphene than 3R-MoS2. In both cases, the best Na host site is found at the MoS2 side of the interface, and the band structure reveals a proper n-type character of the graphene moiety, which is responsible for electronic conduction. Minimum-energy paths for Na diffusion show very low barrier heights for the 3R-MoS2/graphene interface (<0.25 eV) and much higher values for its 1T counterpart (∼0.7 eV). Analysis of structural features along the diffusion transition states allows us to identify the strong coordination of Na with the exposed S atoms as the main feature hindering an effective diffusion in the 1T case. These results provide new hints on the physicochemical details of Na intercalation and diffusion mechanisms at complex 2D heterointerfaces and will help further development of advanced electrode materials for efficient NIBs

    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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
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