1,720,959 research outputs found
Association between asymptomatic carotid atherosclerosis and degenerative aortic stenosis.
Get PDFOBJECTIVE:
Degenerative aortic stenosis shows similarities with atherosclerosis. To confirm the hypothesis that aortic stenosis is an "atherosclerosis-like" disease, we investigated the association between degenerative aortic stenosis and atherosclerosis of carotid arteries.
METHODS:
We studied 270 consecutive patients, 135 with degenerative aortic stenosis (trans-aortic peak velocity ≥ 2 m/sec) and other 135 subjects without aortic valve disease. All patients underwent echocardiography and ultrasound scan of the supra-aortic trunks to assess the presence of plaque and/or intima-media thickening (IMT).
RESULTS:
Atherosclerosis of carotid arteries (IMT and plaque) was significantly more frequent in patients with aortic stenosis than in controls (95.5% vs. 66.6%, p < 0.0001). The same result was confirmed as concerns carotid plaques (69.6% vs. 42.2%, p < 0.0001). In addition, there was a significant association between aortic stenosis and degenerative carotid plaque (OR = 3.13; 95% C.I. = 1.90-5.17). Thus the presence of a linear correlation between the trans-aortic peak velocity of the cases and the thickness of the plaques and IMT was evaluated by calculating the coefficient of correlation (R = 0.15 for plaque and R = 0.53 for IMT).
CONCLUSIONS:
The presence of carotid atherosclerosis is associated with degenerative aortic stenosis and the severity of aortic stenosis corresponds to an increase of the thickness of plaque and IMT. This relationship is quite new. Our result strengthens the pathogenetic hypothesis "atherosclerosis-like" of degenerative aortic stenosis and suggest the ultrasound scan as a non invasive method for risk stratification in patient with aortic stenosis, with therapeutic implications especially for higher risk subgroups
Metabolic syndrome (MetS) predicts cardio and cerebrovascular events in a twenty years follow-up. A prospective study.
No full textBACKGROUND AND PURPOSE:
Metabolic syndrome (MetS) is a cluster of cardiovascular risk factors, considered as emerging and promoting atherosclerosis. This study aimed at the evaluation of the influence of MetS on the prediction of cerebro and cardiovascular events during a 20 years follow-up period in an asymptomatic population of middle-aged subjects.
METHODS:
We evaluated 529 asymptomatic persons through a prospective study. Study population was divided into two subgroups: patients with and without MetS. Echo-color-Doppler was used in order to assess the presence of subclinical atherosclerosis. A 20 years follow-up study was carried out in order to estimate the incidence of cerebro and cardiovascular, fatal and non fatal, events (AMI, stroke, abdominal aortic aneurysm, TIA, angina pectoris).
RESULTS:
242 cerebro and cardiovascular events were registered, 43 fatal (24 in MetS and 19 in controls) and 199 non fatal (120 with MetS and 79 without it, p < 0.0001). Free-events survival was lower in patients suffering from MetS (p < 0.0012; HR 0.6847; C.I.95%: 0.5274-0.8889). Ultrasound showed a higher prevalence of subclinical atherosclerosis in patients with MetS than in the unaffected ones (68.12% vs. 57.5% p < 0.01; OR = 1.58 with C.I.95% = 1.10-2.28, p < 0.01).
CONCLUSIONS:
Patients with MetS have a higher cardiovascular risk that can be explained by atherosclerotic changes: the components of MetS interact to affect vascular thickness synergistically and promote the development of subclinical atherosclerosis. So we recommend to prevent the development of MetS abnormalities and to investigate the presence of subclinical atherosclerosis by echo-color-Doppler in order to stratify more accurately the global CV risk
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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