1,721,258 research outputs found

    Risk stratification and prevention of sudden death in hypertrophic cardiomyopathy.

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    Sudden cardiac death is the most devastating manifestation of hypertrophic cardiomyopathy (HCM) and often occurs in young and previously asymptomatic patients. Therefore, risk stratification for sudden death has a major role in the management of HCM and has acquired even greater relevance since the implantable cardioverter-defibrillator (ICD) has proved to be highly effective in preventing sudden death in this disease. The ICD is definitely indicated for secondary prevention of sudden death in patients with HCM who have survived a cardiac arrest with documented ventricular fibrillation, or experienced one or more episodes of sustained ventricular tachycardia. However, uncertainties persist regarding the precise selection of patients for primary prophylactic ICD implantation. A number of risk markers are used to assess the magnitude of risk, including family history of premature sudden death; extreme left ventricular (LV) hypertrophy (> 30 mm) in young patients; nonsustained ventricular tachycardia on Holter electrocardiographic recording; unexplained (not neurally mediated) syncope, particularly in young patients; and blood pressure decrease or inadequate increase during upright exercise. Multiple risk factors convey a definite increase in risk. However, a single risk factor such as family history of multiple sudden deaths, massive LV hypertrophy in a young patient, or frequent and/or prolonged runs of nonsustained ventricular tachycardia on Holter, may also justify consideration of a prophylactic ICD

    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

    The potential of radiocarbon analysis for the detection of art forgeries

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    Art objects form an essential part of cultural heritage and are appreciated for their artistic values. However, the observed investment in art and capacity for high monetary returns encourages counterfeiting of art objects. The art market's lack of transparency and traditional confidential protocols amplifies the problem. Radiocarbon analysis provides a tool to detect anachronistic materials. Measurement of bomb peak radiocarbon, which was observed in the atmosphere during the last 70 years, can provide clear evidence of post-1950 material. Here we briefly introduce the method and discuss its application in detecting forgeries. Three accelerator mass spectrometry AMS laboratories performed a 14C dating inter-comparison study on the material used in art. Results obtained on modern cotton paper, two antique sheets of paper, one parchment, and one textile demonstrate the radiocarbon dating capacity to date the material accurately. The excellent agreement between laboratories is crucial for the broader application of this scientific tool in forensic studies and court cases

    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

    Plasma enhanced-chemical vapour deposi-tion of scuff-resistant hydrogenated amorphous carbon coatings on C100 steel

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    Hydrogenated amorphous carbon coatings, deposited by low pressure plasma to minimize the wear of C100 steel components, were optimized and characterized. In order to ensure good adhesion of the films to the steel surface, a thin Ti interlayer was deposited, by magnetron sputtering, before the plasma deposition. The chemical characterization of the deposits was performed by means of RAMAN, XPS, RBS and ERDA analysis, while nanoindentation, nanoscratch and nanowear tests allowed to estimate the tribomechanical properties of the deposits, with the aim of evaluating their scuff-resistance. It was found that the optimized plasma deposited hydrogenated amorphous carbon coatings were well adherent to C100 steel and increased more than 70 % its surface hardness
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