1,721,001 research outputs found
The comparison of effects of biologic agents on rheumatoid arthritis damage progression is biased by period of enrolment: data from a systematic review and meta-analysis
No full textObjectives: To indirectly compare the 12-month effects of available biologic agents in slowing RA radiographic progression. Methods: A systematic review of literature of randomised, double-blind, controlled trials (RCTs) evaluating RA radiographic progression as end point was conducted using a PubMed searching of MEDLINE from January 1995 to May 2012. For each trial, the mean change from baseline of the standardised annual radiographic progression score (weighted for estimated annual progression rate) was estimated, and the effect size was calculated as the difference between biologic and non-biologic-treated groups. In order to optimise data homogeneity and improve RCTs comparison, a mixed-effect model was applied including previous responsiveness to methotrexate (MTX-experienced or MTX-naïve populations) and period of study enrolment as moderators. Results: The PubMed search resulted in 183 references, and 14 were eligible for the meta-analysis. The analysis of study distribution in forest plots showed a high correlation between the study period of enrolment and the impact of biological therapy in both MTX-naïve and MTX-experienced subgroups. In particular, effect size was the highest for older trials and progressively decreased in the most recent ones, suggesting a highest propensity to radiographic progression in populations enroled in older trials. Some statistically significant differences among RCTs were found in both subgroups but were significantly biased by the different propensity to radiographic progression due to period of enrolment. Conclusions: Our meta-analysis demonstrated that period of enrolment deeply influence study population propensity to radiographic progression in each trial. This finding does not allow the indirect comparison of various biologic agents, despite our mixed-model significantly reducing heterogeneity among RCTs
Evaluation of the influence of open and closed-ampoule technologies on particulate matter in small-volume parenterals
No full textSVP in glass ampoules are manufactured using two main different technological production processes: the open-ampoule process (O) and the closed-ampoule process (C). In principle, the open-ampoule production technology should lead to better controlled production process. To test this hypothesis and quantify the possible qualitative differences in the manufactured ampoules, a suitable experimental design was set up. The two ampoule production processes have been compared on the basis of the visible particulate burden. Two batches of ampoules filled with water for injections were produced for each type of process, following conventional industrial procedures. Two samples of 20,000 units were taken from each batch and inspected with different automatic inspection systems: two Brevetti CEA machines (S1, S2-light scattering) and two EISAI machines (S3, S4-light absorbtion). The comparison between the processes was based on the rejection percentage. On both inspection machines the open-ampoule production samples present rejection percentages (ranging from 0.154% to 1.248% rejection percentages) which, on average, are lower than those detected in closed- ampoule production (ranging from 1.434% to 3.86% rejection percentages). The difference between the two processes is even more marked if we also consider the data obtained using inspection machines S3 and S4. The substantial differences in performance of the four inspection machines stress the need to provide for adequate validation procedures
The role of biologic agents in damage progression in rheumatoid arthritis: indirect comparison of data coming from randomized clinical trials
No full textAll biologic agents approved for the treatment of rheumatoid arthritis (RA) have been tested versus methotrexate (MTX) for efficacy on damage progression in several randomized clinical trials (RCTs), but direct head-to-head comparisons have never been conducted. The purpose of this investigation is to analyse data coming from main RA RCTs and to perform an indirect comparison. Methods: A systematic review of literature from 1988 to 2011 was conducted. Only randomized, double-blind, controlled, comparative trials, with evaluation of radiographic progression were included. The radiographic score was standardized and mean difference in the percentage of the annual radiographic progression rate was used as the effect measure. Heterogeneity between studies was estimated by I2 test. For each trial, the effect was plotted according to its standard error in a funnel plot. Results: Of 44 potentially relevant trials, 12 RCTs were included in the study. In order to optimize RCTs comparison, studies were stratified in early and late RA group. Main population characteristics were similar in both early and late RA groups, whereas the standardized baseline radiographic score value significantly differs among trials in both early (range 2.7–21.9) and late (range 23.46–75) RA groups. The standardized annual estimated progression is similar across the late RA group. Strong evidence of heterogeneity (I2 = 97%, p = 0.00001) but no asymmetry of the funnel plot was observed in the early RA group. Total mean difference was −16.28 (95% confidence interval [CI] −24.42 to −8.14). For the late RA group a random model was used (I2 = 99%, p = 0.00001) and a total mean difference of −39.25 (95% CI −53.77 to −24.73) was found. All biologic agents provide a favourable effect on disease progression both in early and late RA. The significant heterogeneity among various RCTs did not allow an effective comparison of the performance of biologic agents in each study
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
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
- …
