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Age-related heart rate response to exercise in heart transplant recipients. Functional significance
No full textThe heart rate (HR) and O(2) uptake (VO(2)) responses to cycle ergometer exercise and the role of O(2) transport in limiting submaximal and maximal aerobic performance were assessed in 33 heart transplant recipients (HTR) [14 children (P-HTR), 11 young adults (YA-HTR) and 8 middle-age adults (A-HTR)] and in 28 age-matched control subjects (CTL). In 7 P-HTR ("responders") the HR response to the onset of exercise (on-response) was as fast as that of CTL, whereas in all other patients ("non-responders") the HR on-response was typical of the denervated heart. Compared with non-responder P-HTR, responder P-HTR were also characterized by a normal peak HR (177+/- 16 vs. 151+/- 25 beats/min), an equally slow time constant for the VO(2) on-response (tau: 54 +/- 11 vs. 62+/- 13 s) and a similar low (approximately 60% of that of CTL) peak VO(2) (28 +/- 7 vs. 26 +/- 10 ml/kg per min). On the other hand non-responder YA-HTR and A-HTR were characterized by a relatively low peak HR (151 +/- 21 and 144 +/- 29 beats/min, respectively), a slow tau for the on-response (63 +/- 12 and 70 +/- 11 s) and a low peak (28 +/- 7 and 19 +/- 6 ml/kg per min). In conclusion, a sizeable number of paediatric patients (responder P-HTR) may reacquire the normal HR response to exercise, both in terms of kinetics and maximal level. Despite the almost complete recovery of cardiovascular function, and, probably, oxygen delivery, both the kinetics of the VO(2) on-response and the maximal aerobic power of the responder P-HTR were similar to those of non-responder P-HTR. The latter finding is probably attributable to peripheral limitations, due to inborn and/or pharmacological muscle deterioration
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
The heart rate response to exercise and circulating catecholamines in heart transplant recipients
No full textThe plasma concentration of noradrenaline ([NA]) is higher than that of adrenaline ([A]) both in normal subjects and in heart transplant recipients (HTR). Since in both groups the myocardial density of beta1-adrenergenic receptors is much greater than that of beta2-adrenergenic receptors, the chronotropic response of a denervated heart to changes in plasma [NA] and [A] in the absence of reinnervation should be similar to that of agonist stimulation of beta1-receptors. To test this hypothesis, 17 HTR and 9 healthy subjects (CTL) performed incremental exercise on a cycle ergometer to voluntary exhaustion. Heart rate (HR) was recorded by electrocardiography. [NA] and [A] were measured by high-pressure liquid chromatography at rest and at increasing workloads (w). In both groups, HR and [NA+A] increased with w, and HR with [NA+A]. Normalized HR values, plotted against the logarithm of [NA+A], fitted significantly logistic curves. The affinity constants were different, i.e. 2599+/-350 and 487+/-37 ng.l(-1), for HTR and CTL, respectively. The chronotropic effect of changes in [NA+A] in HTR was similar to that of combined beta1- and beta2-adrenergic activation evoked by applying isoprenaline to isolated heart myocytes (Brodde OE, Pharmacol Ther 60:405-430, 1993). These findings suggest that over time sympathetic reinnervation and the modulation of beta-receptors may take place in HTR, ruling out the hypothesis of persistent heart denervation
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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