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    Possible influence of hemodynamic and neurohormonal factors on the heart's response to arterial hypertension

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    Hypertrophy represents a frequent but inconstant response of the heart to hypertension and probably other nonhemodynamic factors are involved. We have performed 2D and Doppler echocardiography and assessed of neurohumoral pattern in 85 untreated patients with hypertension (diastolic blood pressure: 101 +/- 12.8 mmHg). Left ventricular hypertrophy was defined as a mass index greater than 134 g/m2 in males and 110 g/m2 in females. Doppler evaluation of left ventricular filling pattern was performed to detect the possible association of hypertrophy and diastolic dysfunction. In all patients the following neurohumoral substances were sampled and tested: plasmatic renin activity (PRA), aldosterone and norepinephrine. At Doppler echocardiography, 27 patients had hypertrophy and diastolic dysfunction, 15 only hypertrophy and 43 only diastolic dysfunction. The presence or absence of morpho-functional anomalies were independent of age, duration of hypertension and blood pressure levels. The mean value of neurohumoral substances were: norepinephrine 323.3 +/- 245 pg/ml, PRA 2.5 +/- 4 ng/ml/h, aldosterone 153.58 +/- 102 pg/ml. A significant correlation was found between PRA and blood pressure, and between aldosterone and all the Doppler-derived parameters of diastolic dysfunction. In conclusion, left ventricular hypertrophy seems to be related to alteration in ventricular geometry rather than to hemodynamic factors. Among nonhemodynamic factors, aldosterone may be the most responsible for abnormal filling, presumably through the activation of collagen matrix growt

    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
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