1,720,975 research outputs found
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
Heart rate as a sympathetic marker during acute adrenergic challenge
No full textObjective: Previous studies have shown that heart rate has a limited value in reflecting the chronic state of adrenergic overdrive characterizing several cardiovascular diseases. Whether this also applies to the ability of heart rate to reflect acute and generalized changes in sympathetic activity is unknown.
Methods: In 20 healthy young subjects (age: 25.2 ± 1.2 years, mean ± SEM) we measured beat-to-beat blood pressure (Finapres), heart rate (HR, ECG), venous plasma norepinephrine (NE, high-performance liquid chromatography) and efferent postganglionic muscle sympathetic nerve traffic (MSNA, microneurography) at rest and during a cold pressor test and two intravenous infusions of nitroprusside at increasing doses.
Results: Both cold pressor test and nitroprusside infusions triggered marked and significant increases in HR, plasma NE and MSNA; blood pressure showing an increase with cold pressor test and a reduction with nitroprusside. The magnitude of the responses was greater with the higher than with the lower dose of nitroprusside. The HR changes induced by cold pressor test were not significantly related to the concomitant NE and MSNA changes (r = -0.08 and r = -0.18, P = NS). This was also the case for the lower and the higher dose of nitroprusside (NE: r = -0.11 and r = 0.08; MSNA: r = 0.01 and r = -0.11, P = NS for all). In contrast NE and MSNA changes induced by cold pressor test and by the lower and the higher dose of nitroprusside were significantly related to each other (r = 0.70, r = 0.89 and r = 0.79 respectively, P < 0.01 for all).
Conclusions: In a given individual, HR responses to sympathetic challenge do not quantitatively reflect the degree of acute and generalized adrenergic activation. Qualitative information on the acute adrenergic effects of given stimuli should thus be based on the assessment of NE and MSNA rather than on HR changes
Prevalence of cardiovascular risk factors in an unselected italian population : results of the CardioLab project 2004-2008
No full textObjective - Screening and educational campaigns on cardiovascular (CV) risk factors are important for primary and secondary prevention of CV disease. The CardioLab project is an observational cross-sectional study aimed at determining the prevalence of CV risk factors in a large unselected sample of the Italian population leaving in northern, central and southern Italy. Methods and results - Data collection included family and clinical history, anthropometric data, blood pressure, blood glucose and total cholesterol values. Individual CV risk profile was assessed throughout by the risk charts of both the Progetto Cuore and the Score Project. In 36,161 participants (56.3% men) with a mean age of 60 years a complete assessment of the above mentioned variables was obtained. 44.4% of the screened subjects was overweight, while approximately 20% of the population displayed an obese state with a body mass index > 30 kg/m 2. Alterations in blood glucose levels indicating the presence of glucose intolerance were identified in 11.5% of the population while 9.3% displayed overt diabetes. 36.1% and 42.3% had elevated total cholesterol levels (> 200 mg/dl) and blood pressure values (> 140/90 mmHg), respectively. New diagnosis of diabetes, hypercholesterolaemia and hypertension was obtained in 5.3%, 23.6% and 19.6%, respectively. Global assessment of the CV risk showed that approximately 12.6% of the population is at a high risk of CV events over a 10-year period. Conclusions - This large-scale observational study provides important information on the CV risk profile of an unselected Italian population and underlines the need for a more aggressive identification and appropriate correction of CV risk factors
Sympathetic activation in congestive heart failure : Reproducibility of neuroadrenergic markers
No full textObjective: To assess the reproducibility of the two markers of adrenergic drive, venous plasma norepinephrine (NE) and efferent postganglionic muscle sympathetic nerve activity (MSNA), in reflecting the sympathetic activation characterizing congestive heart failure (CHF).
Methods and measurements: In 19 CHF male normotensive patients (mean age: 53.0 +/- 2.1 years, NYHA classes II and III, left ventricular ejection fraction 35.9 +/- 2.9%), blood pressure (BP, Finapres), heart rate (EKG), plasma NE (HPLC assay) and MSNA (microneurography, peroneal nerve) were measured in two experimental sessions separated by a week interval. At each session, three NE samples were obtained and NE reproducibility between sessions was assessed by considering single NE samples or averaging 2-3 samples.
Results: While MSNA values showed a highly significant correlation between sessions (r = 0.85, P < 0.001), NE values based on a single blood sample evaluation did not correlate with each other (r = 0.41, P = NS). NE correlation coefficients improved and achieved statistical significance when average data from 2 and 3 blood samples were examined (r = 0.54 and r = 0.57, P < 0.02 for both).
Conclusions: In CHF, MSNA displays a better reproducibility pattern than plasma NE. The reproducibility of the NE approach, however, can be improved by performing the assay on multiple blood samples. (C) 2008 European Society of Cardiology
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
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