1,720,976 research outputs found
Clinical impact of myocardial fibrosis in severe aortic stenosis
Full text linkThe pressure overload due to the progressive narrowing of the valve area determines the development of the left ventricular hypertrophy which characterizes aortic stenosis (AS). The onset of myocardial fibrosis marks the inexorable decline of an initially compensatory response towards heart failure. However, myocardial fibrosis does not yet represent a key element in the prognostic and therapeutic framework of AS. In this context, cardiac magnetic resonance imaging plays a major role by highlighting both the focal irreversible fibrotic replacement, using the late gadolinium enhancement (LGE) technique, and the earlier diffuse reversible interstitial fibrosis, using the T1 mapping techniques. For this reason, the presence of myocardial fibrosis would be useful to identify a subgroup of patients at greater risk of events among the subjects with severe AS. Actually, more and more evidences seem to identify the presence of LGE as a powerful prognostic factor to be used to optimize the timing of prosthetic valve replacement. Randomized clinical trials, such as the EVoLVeD trial currently underway, will be needed to better define the importance of myocardial fibrosis assessment in the management of patients with AS
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
The right ventricular involvement in dilated cardiomyopathy: prevalence and prognostic implications of the often-neglected child
Full text linkDilated cardiomyopathy (DCM) is a primary heart muscle disease characterized by left or biventricular systolic impairment. Historically, most of the clinical attention has been devoted to the evaluation of left ventricular function and morphology, while right ventricle (RV) has been for many years the forgotten chamber. Recently, progresses in cardiac imaging gave clinicians precious tools for the evaluation of RV, raising the awareness of the importance of biventricular assessment in DCM. Indeed, RV involvement is far from being uncommon in DCM, and the presence of right ventricular dysfunction (RVD) is one of the major negative prognostic determinants in DCM patients. However, some aspects such as the possible role of specific genetic mutations in determining the biventricular phenotype in DCM, or the lack of specific treatments able to primarily counteract RVD, still need research. In this review, we summarized the current knowledge on RV involvement in DCM, giving an overview on the epidemiology and pathogenetic mechanisms implicated in determining RVD. Furthermore, we discussed the imaging techniques to evaluate RV function and the role of RV failure in advanced heart failure
Autonomic function in Takotsubo syndrome long after the acute phase
No full textObjectives Although it is well documented that an exaggerated sympathetic stimulation plays a role in the development of Takotsubo Syndrome (TS) during the acute phase, only few studies have focused on autonomic adaptations in stress-induced cardiomyopathy long after the acute phase. Aim of the study was to investigate whether an impairment of the autonomic function is still present long after a TS event. This was done by comparing the response to a maximal exercise test in TS patients after apparent recovery (> 1-year after the acute event) with that obtained in healthy subjects and in post-myocardial infarction (post-MI) patients. Methods To assess heart rate recovery (HRR) and chronotropic response (CR), 24 TS patients, 25 healthy subjects and 22 post-MI patients underwent maximal exercise test, after at least 3 days of β-blockers wash-out. Results HRR in TS patients (19.2 ± 9.7 bpm) was lower than in healthy subjects (27.7 ± 8.3, p = 0.003), and similar to post-MI patients (19.3 ± 8.4; p = 0.99). A decreasing CR trend (p=0.06), higher in healthy subjects (72±13%) than in TS (65±22%) and post-MI (57±21%) patients, was also found. Conclusion Compared to healthy subjects, TS patients showed a blunted parasympathetic reactivation after exercise, similar to that observed in post-MI patients, thereby suggesting that vagal control of heart rate after exercise is abnormal long after the acute presentation of TS
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