1,720,965 research outputs found
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
Symptoms as a predictor of the placebo-controlled efficacy of PCI in stable coronary artery disease
No full textBackground: placebo-controlled evidence from ORBITA-2 (Objective Randomised Blinded Investigation with Optimal Medical Therapy of Angioplasty in Stable Angina-2) found that percutaneous coronary intervention (PCI) in stable coronary artery disease with little or no antianginal medication relieved angina, but residual symptoms persisted in many patients. The reason for this was unclear.Objectives: this ORBITA-2 secondary analysis investigates the relationship between presenting symptoms and disease severity (anatomic, noninvasive, and invasive ischemia) and the ability of symptoms to predict the placebo-controlled efficacy of PCI.Methods: prerandomization symptom severity and nature were assessed using the ORBITA smartphone application and symptom and quality of life questionnaires including the World Health Organization Rose angina questionnaire (Rose). Disease severity was assessed using quantitative coronary angiography, stress echocardiography, fractional flow reserve, and instantaneous wave-free ratio. Bayesian ordinal regression was used.Results: at prerandomization, the median number of daily angina episodes was 0.8 (Q1-Q3: 0.4-1.6), 64% had Rose angina, quantitative coronary angiography diameter stenosis was 61% (Q1-Q3: 49%-74%), stress echocardiography score was 1.0 (Q1-Q3: 0.0-2.7), fractional flow reserve was 0.63 (Q1-Q3: 0.49–0.75), and instantaneous wave-free ratio was 0.78 (Q1-Q3: 0.55-0.87). There was little relationship between symptom severity and nature and disease severity: angina symptom score with quantitative coronary angiography ordinal correlation coefficient: 0.06 (95% credible interval [CrI]: 0.00-0.08); stress echocardiography: 0.09 (95% CrI: 0.02-0.10); fractional flow reserve: 0.04 (95% CrI: −0.03 to 0.07); and instantaneous wave-free ratio: 0.04 (95% CrI: −0.01 to 0.07). However, Rose angina and guideline-based typical angina were strong predictors of placebo-controlled PCI efficacy (angina symptom score: OR: 1.9; 95% CrI: 1.6-2.1; probability of interaction [PrInteraction] = 99.9%; and OR: 1.8; 95% CrI: 1.6-2.1; PrInteraction = 99.9%, respectively).Conclusions: although symptom severity and nature were poorly associated with disease severity, the nature of symptoms powerfully predicted the placebo-controlled efficacy of PCI.<br/
Ischemia on dobutamine stress echocardiography predicts efficacy of PCI: results from the ORBITA-2 trial
No full textBackground: ORBITA-2 (The Placebo-Controlled Trial of Percutaneous Coronary Intervention for the Relief of Stable Angina) found that percutaneous coronary intervention (PCI) relieved angina in patients with single-vessel and multivessel stable coronary artery disease (CAD) on little or no antianginal medication. Whereas symptom characteristics and invasive physiological assessments can predict PCI efficacy, the role of noninvasive imaging with dobutamine stress echocardiography (DSE) remains unclear.Objectives: this DSE-stratified secondary analysis of ORBITA-2 investigates the relationship between ischemia, assessed by DSE, and the placebo-controlled efficacy of PCI.Methods: participants with angina, single-vessel or multivessel CAD, and ischemia were enrolled. Following discontinuation of antianginal medications, patients were evaluated prerandomization using the ORBITA-app, questionnaires, DSE, and exercise treadmill testing. Stress echocardiography scores were calculated for each left ventricular segment at peak stress, with normal, hypokinetic, akinetic, dyskinetic, and aneurysmal segments scoring 0 to 4, respectively. Bayesian proportional odds modeling was used.Results: prerandomization DSE data were available for 262 patients. The median age was 65.5 years (Q1-Q3: 59-71 years), and 208 (79.4%) were male. At baseline, the median stress echocardiography score was 1.42 in the PCI group (n = 133) and 1.00 in the placebo group (n = 129), with an overall median score of 1.25 (Q1-Q3: 0.33-2.92). Higher stress echocardiography scores were strongly associated with greater placebo-controlled improvements in angina symptom score following PCI (OR: 1.23; 95% credible interval [CrI]: 1.13-1.35; Pr(interaction) > 99.9%). Higher scores also predicted significant reduction in daily angina episodes (OR: 1.36; 95% CrI: 1.24-1.49; Pr(interaction) > 99.9%), as well as improvement in the Seattle Angina Questionnaire angina frequency score (8.22; 95% CrI: 0.96-15.50; Pr(interaction) = 98.7%), and Seattle Angina Questionnaire quality of life score (8.95; 95% CrI: 2.05-16.00; Pr(interaction) = 99.3%). The relationship between stress echocardiography score and reduction in daily angina episodes remained consistent, irrespective of symptom characteristics.Conclusions: in patients with single- and multivessel stable CAD on little or no antianginal medication, the placebo-controlled efficacy of PCI was predicted by the degree of ischemia detected on DSE. The greater the burden of baseline ischemia, the greater the improvement in symptoms and quality of life with PCI
Fractional flow reserve and instantaneous wave-free ratio as predictors of the placebo-controlled response to percutaneous coronary intervention in stable coronary artery disease
No full textBackground: ORBITA-2 (the Placebo-controlled Trial of Percutaneous Coronary Intervention for the Relief of Stable Angina) provided evidence for the role of percutaneous coronary intervention (PCI) for angina relief in stable coronary artery disease (CAD). Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are often used to guide PCI; however, their ability to predict placebo-controlled angina improvement is unknown.Methods: participants with angina, ischemia, and stable CAD were enrolled and antianginal medications were stopped. Participants reported angina episodes daily for 2 weeks using the ORBITA-app. At the research angiogram, FFR and iFR were measured. After sedation and auditory isolation, participants were randomized to PCI or placebo, before entering a 12-week blinded follow-up phase with daily angina reporting. The ability of FFR and iFR, analyzed as continuous variables, to predict the placebo-controlled effect of PCI, was tested using Bayesian proportional odds modelling.Results: invasive physiology data were available in 279 patients (140 PCI and 139 placebo). The median (IQR) age was 65 years (59.0 to 70.5) and 223 (79.9%) were male. Median FFR was 0.60 (0.46 to 0.73) and median iFR was 0.76 (0.50 to 0.86). The lower the FFR or iFR, the greater the placebo-controlled improvement with PCI across all endpoints. There was strong evidence that a patient with an FFR at the lower quartile would have a greater placebo-controlled improvement in angina symptom score with PCI than a patient at the upper quartile (FFR 0.46 vs. 0.73: OR 2.01, 95% CrI 1.79 to 2.26, Pr(Interaction)>99.9%). Similarly, there was strong evidence that a patient with an iFR at the lower quartile would have a greater placebo controlled improvement in angina symptom score with PCI than a patient with an iFR at the upper quartile (iFR 0.50 vs. 0.86: OR 2.13, 95% CrI 1.87 to 2.45, Pr(Interaction) >99.9%). The relationship between benefit and physiology was seen in both Rose angina and Rose nonangina.Conclusions: physiological stenosis severity, as measured by FFR and iFR, predicts placebo-controlled angina relief from PCI. Invasive coronary physiology can be used to target PCI to those patients who are most likely to experience benefit.<br/
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
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