1,721,161 research outputs found
Coronary vasodilator reserve in primary and secondary left ventricular hypertrophy - A study with positron emission tomography
No full textObjectives Coronary vasodilator reserve is reduced in hypertrophic cardiomyopathy and secondary left ventricular hypertrophy despite angiographically normal coronaries. The aim of the present study was to assess whether quantitative differences exist between these conditions. Methods Using positron emission tomography with (H2O)-O-15, myocardial blood flow was measured at baseline and following intravenous dipyridamole (0 . 56 mg.kg(-1)) in 12 hypertrophic cardiomyopathy patients (age 34 (11) years, mean (SD), all male), 16 secondary left ventricular hypertrophy patients (age 58 (20) years: P<0 . 01 vs hypertrophic cardiomyopathy; 10 female) and 40 normal controls (age 54 (20), 13 female). In view of the known decline of post-dipyridamole myocardial blood flow with age, myocardial blood flow was compared between the patient groups and appropriately matched subsets of the total control group. Results Baseline myocardial blood Bow in the hypertrophic cardiomyopathy patients was 0 . 82 (0 . 23) ml.min(-1).g(-1) vs 0 . 94 (0 . 14) ml.min(-1).g(-1) in its matched control group, P=ns. For the secondary left ventricular hypertrophy patient group, baseline myocardial blood flow was 1 . 17 (0 . 40) ml.min(-1).g(-1) vs 1 . 06 (0 . 28) ml.min(-1).g(-1) for the secondary left ventricular hypertrophy matched control group, P=ns. Following dipyridamole, myocardial blood flow was 1 . 64 (0 . 44) ml.min(-1).g(-1) in hypertrophic cardiomyopathy patients vs 3 . 50 (0 . 95) ml.min(-1).g(-1) for the hypertrophic cardiomyopathy matched control group, P=0 . 0001. For the left ventricular hypertrophy patients, post-dipyridamole myo-cardial blood flow was 2 . 27 (0 . 60) ml.min(-1).g(-1) vs 2 . 94 (1 . 29) ml.min(-1).g(-1) for the left ventricular hypertrophy controls, P=0 . 06. Coronary vasodilator reserve (dipyridamole-myocardial blood flow/baseline-myocardial blood flow) was 2 . 05 (0 . 61) for hypertrophic cardiomyopathy patients vs 3 . 81 (0 . 98) for the hypertrophic cardiomyopathy controls (P=0 . 0001, patients vs controls) and 2 . 06 (0 . 62) for left ventricular hypertrophy patients vs 2 . 90 (1 . 38) for the left ventricular hypertrophy controls, P<0 . 03 patients vs controls. After correction of baseline myocardial blood flow for baseline heart rate x systolic pressure product, coronary vasodilator reserve for the hypertrophic cardiomyopathy patients was 2 . 06 (1 . 06) vs 4 . 34 (1 . 54) for the hypertrophic cardiomyopathy controls, P=0 . 0002 and in the secondary left ventricular hypertrophy patients, the values were 2 . 13 (0 . 64) vs 2 . 89 (1 . 42) in the secondary left ventricular hypertrophy controls, P<0 . 05. Conclusion In both hypertrophic cardiomyopathy and secondary left ventricular hypertrophy, the computed coronary vasodilator reserve is impaired, even after correction for baseline cardiac work. However, the extent of the reduction is greater in the hypertrophic cardiomyopathy patients. In the blunting of vasodilator reserve of secondary left ventricular hypertrophy, the patients' greater hyperaemic response is partly offset by the higher baseline myocardial blood flow
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
Different ECG methods ro assess canges in QRS duration with dobutamine stress echocardiography
No full textVariations 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
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
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