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    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

    Impact of obstructive sleep apnoea on diastolic function

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    We investigated whether obstructive sleep apnoea (OSA) independently affects diastolic function in a primary care cohort of patients with cardiovascular risk factors. 378 study participants with risk factors for diastolic dysfunction were prospectively included and a polygraphy was performed in all patients. Diastolic dysfunction was assessed by comprehensive echocardiography including tissue Doppler. Sleep apnoea was classified according to apnoea/hypopnoea index (AHI) as none (AHI = 15 events.h(-1)). Patients with central sleep apnoea (n=14) and patients with previously diagnosed sleep apnoea (n=12) were excluded. In the remaining 352 subjects, 21.6% had an AHI >= 15 events.h(-1). The prevalence of diastolic dysfunction increased with the severity of sleep apnoea from 44.8% (none) to 56.8% (mild) to 69.7% (moderate-to-severe sleep apnoea) (p=0.002). The degree of diastolic dysfunction also increased with sleep apnoea severity (p=0.004). In univariate regression analysis, age, desaturation index, AHI, cardiac frequency, angiotensin receptor 1 antagonist therapy, body mass index (HMI) and left ventricular mass were associated with diastolic dysfunction. In multivariate regression analysis, only age, BMI, AHI and cardiac frequency were independently associated with diastolic dysfunction. Moderate-to-severe OSA is independently associated with diastolic dysfunction in patients with classical risk factors for diastolic dysfunction

    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

    Blunted frequency-dependent upregulation of cardiac output is related to impaired relaxation in diastolic heart failure

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    We tested the hypothesis that, in heart failure with normal ejection fraction (HFNEF), diastolic dysfunction is accentuated at increasing heart rates, and this contributes to impaired frequency-dependent augmentation of cardiac output. In 17 patients with HFNEF (median age 69 years, 13 female) and seven age-matched control patients, systolic and diastolic function was analysed by pressure-volume loops at baseline heart rate and during atrial pacing to 100 and 120 min(-1). At baseline, relaxation was prolonged and end-diastolic left ventricular stiffness was higher in HFNEF, whereas all parameters of systolic function were not different from control patients. This resulted in smaller end-diastolic volumes, higher end-diastolic pressure, and a lower stroke volume and cardiac index in HFNEF vs. control patients. During pacing, frequency-dependent upregulation of contractility indices (+dP/dt(max) and Ees) occurred similarly in HFNEF and control patients, but frequency-dependent acceleration of relaxation (dP/dt(min)) was blunted in HFNEF. In HFNEF, end-diastolic volume and stroke volume decreased with higher heart rates while both remained unchanged in control patients. In HFNEF, frequency-dependent upregulation of cardiac output is blunted. This results from progressive volume unloading of the left ventricle due to limited relaxation reserve in combination with increased LV passive stiffness, despite preserved force-frequency relation

    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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