1,721,075 research outputs found
Comparative Superiority of ACE Inhibitors over Angiotensin Receptor Blockers for People with CKD: Does It Matter?
No full text
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
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
A fully Bayesian application of the Copas selection model for publication bias extended to network meta-analysis.
No full textThe Copas parametric model is aimed at exploring the potential impact of publication bias via sensitivity analysis, by making assumptions regarding the probability of publication of individual studies related to the standard error of their effect sizes. Reviewers often have prior assumptions about the extent of selection in the set of studies included in a meta-analysis. However, a Bayesian implementation of the Copas model has not been studied yet. We aim to present a Bayesian selection model for publication bias and to extend it to the case of network meta-analysis where each treatment is compared either with placebo or with a reference treatment creating a star-shaped network. We take advantage of the greater flexibility offered in the Bayesian context to incorporate in the model prior information on the extent and strength of selection. To derive prior distributions, we use both external data and an elicitation process of expert opinion
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
Comparative Effectiveness of Calcimimetic Agents for Secondary Hyperparathyroidism in Adults: A Systematic Review and Network Meta-analysis
No full textRationale & Objective: Comparative benefits and harms of calcimimetic agents used for the treatment of secondary hyperparathyroidism have not been well characterized. We sought to compare the effectiveness of 3 calcimimetic agents using published data. Study Design: Systematic review of randomized controlled trials and network meta-analysis. Setting & Study Population: Adults with chronic kidney disease enrolled in a clinical trial of a calcimetic agent. Search Strategy & Sources: MEDLINE, EMBASE, CENTRAL (from February 7, 2013, to November 21, 2019), and a published meta-analysis. Data Extraction: Two reviewers independently extracted the study data, assessed risk of bias, and rated evidence certainty using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Analytical Approach: Frequentist network meta-analysis was conducted. The primary review outcomes were achievement of a target reduction in serum parathyroid hormone (PTH) levels and hypocalcemia. Additional outcomes were nausea, vomiting, serious adverse events, all-cause mortality, cardiovascular mortality, heart failure, and fracture. Results: 36 trials (11,247 participants) were included. All except 4 trials involved dialysis patients. Median follow-up was 26 weeks (range, 1 week to 21.2 months). Compared with placebo, calcimimetic agents had higher odds of achieving target PTH levels with high or moderate certainty. Etelcalcetide had the highest odds of achieving a PTH target compared with evocalcet (OR, 4.93; 95% CI, 1.33-18.2) and cinacalcet (OR, 2.78; 95% CI, 1.19-6.67). Etelcalcetide appeared to cause more hypocalcemia than cinacalcet and evocalcet. Cinacalcet and to a lesser extent etelcalcetide appeared to cause more nausea than placebo. Differences in risk for mortality, cardiovascular end points, or fractures across calcimimetic agents could not be discerned with sufficient certainty. Limitations: Lack of longer-term data; heterogeneous end point definitions. Conclusions: Evidence of the benefits of calcimimetic therapy is limited to short-term assessment of a putative surrogate outcome (serum PTH). Although etelcalcetide was associated with the largest reduction in PTH levels, side-effect profiles differed across the 3 calcimimetic agents, making it not possible to identify 1 preferred agent
Placebo response in psoriatic arthritis clinical trials: a systematic review and meta-analysis
No full textObjective: To determine the placebo response rate in PsA randomized clinical trials (RCTs), its contributing factors and impact on the effect size of active treatments. Methods: We searched multiple databases, from inception to 20 December 2020, for placebo-controlled RCTs in PsA. We used a random-effects meta-analysis to pool the response rates for the ACR20 criteria in the placebo arm, determined the risk difference for treatment vs placebo, and used meta-regression to determine the factors associated with placebo response rates. The risk of bias was assessed in duplicate. The study protocol was registered with PROSPERO: CRD42021226000. Results: We included 42 RCTs (5050 patients receiving placebo) published between 2000 and 2020. The risk of bias was low in 28 trials, high in four, and with some concerns in 10. The pooled placebo response rate was 20.3% (95% CI: 18.6%, 22.1%; predicted intervals, 11.7-29.0%), with significant between-trial heterogeneity (I2 = 56.8%, P < 0.005). The pooled risk difference for treatment vs placebo was 27% (95% CI: 24%, 31%). In the multivariable meta-regression, there was a 15% (95% CI: 2.9%, 29.8%) increase in the odds of achieving the placebo response for each 5-year increment in publication year (P = 0.016). In addition, the active treatment risk difference decreased for every 5-year increment in publication year (β = -0.053, 95% CI: -0.099, -0.007; P = 0.024) but was not associated with the placebo response. Conclusion: Despite increasing over time, the placebo response for ACR20 in PsA RCTs was not associated with the active treatment effect size
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