1,720,955 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
Behavioral and hormonal measures of hunger, satiety, and energy intake to predict weight-loss response to Liraglutide
No full textWeight loss for treating obesity requires a sustained negative energy balance. Various pharmacological agents facilitate weight loss by helping reduce energy intake. Pharmacotherapy for obesity has limitations, and efficacy and safety profiles of obesity drugs vary. Therefore, predicting responders to drug treatment early on can avoid undue exposure of potential non-responders to drug side effects. This study was conducted to predict weight-loss response to anti-obesity drug liraglutide, an FDA-approved glucagon-like peptide-1 (GLP-1) receptor agonist that helps reduce food intake and promote weight loss. It is expected that subjective (visual analog scale [VAS] ratings) and objective (ad libitum intake and hunger and satiety hormones) measures of energy intake, hunger, and satiety work in consort with food cue reactivity in the brain to influence food intake, which in turn impacts weight and objective measures of energy intake, hunger, and satiety in response to liraglutide would predict weight loss and that responders to liraglutide (defined by at least 4% weight loss at 16 weeks) have stronger interplay between measures of hunger and satiety. This would strongly reduce food intake and, in turn, may induce greater weight loss. To test this, analysis of the interaction between measures of hunger and satiety with FCR in the brain and weight loss are needed. This study focused on the relationship between gut hormones, subjective measures of hunger and satiety, and food intake and weight loss. We tested this in a 16-week randomized, double-blind, placebo-controlled trial. Subjects with obesity (age 18-60 years; body mass index 30-50 kg/m2) were recruited via advertisement. Sixty-three individuals initiated the study. An initial 4-week dose escalation phase for liraglutide (or placebo) was followed by 12 weeks of maintenance of the therapeutic dose (3.0 mg). At baseline, week 4, and week 16, subjects attended testing sessions for functional magnetic resonance imaging-food cue reactivity (fMRI-FCR) scans. During the visit, they were offered a standardized breakfast and responded to VAS, provided blood samples for measuring hormone levels and other parameters at several timepoints and after an ad libitum lunch. Changes in body weight, hormonal (ghrelin, PYY, and GLP-1) response to food intake, and behavioral (ad libitum food intake and self-reported hunger/satiety assessed with VAS) responses from baseline to week 4 and baseline to week 16 were analyzed (while blinded to group allocation) using R statistical software and intention-to-treat with multiple imputation to handle missingness. Comparisons were performed using linear models (continuous outcomes) or logistic regression (binary outcomes), with analyses within imputations pooled into a single, final analysis using Rubin’s Rules.
Sixty-three subjects were included in the intention-to-treat analysis. After 16 weeks, mean weight loss in the placebo group (n=30) was 3.1±5.9% (mean ± SEM) and -10.2±3.8% in the liraglutide group (n=33; p=0.326). Placebo or liraglutide group did not differ significantly in changes in area-under-the-curve (AUC) and area-under-the-curve correcting for the baseline value (cAUC) in VAS in baseline to week 4 and baseline to week 16 changes. Baseline to week 4 change in VAS, ad libitum lunch intake, and PYY, GLP-1, and ghrelin did not predict percent weight loss or responder status (at least 4% weight loss) at 16 weeks in the liraglutide group (all p>0.05). Sex (p=0.399), age (p=0.205), and initial BMI (from baseline scan visit; p=0.421) did not predict liraglutide responder status at 16 weeks. Liraglutide responders did not have significantly different baseline PYY, GLP-1, and ghrelin AUCs or cAUCs than non-responders (all p>0.05). There were no significant differences between responders and non-responders for baseline to week 4 and baseline to week 16 changes in PYY, GLP-1, and ghrelin (all p>0.05). We did not observe a statistically significant difference between placebo and liraglutide groups for measures of hunger and satiety, energy intake, and weight loss in this trial of 63 participants. This is expected because sample size calculations were based on observing FCR for those exposed to liraglutide and placebo and not for detecting differences in weight loss or weight-loss related subjective and objective measures of hunger and satiety between groups. The next phase of analyses will determine if FCR is linked to measures of hunger and satiety, energy intake, and weight-loss response. This collective interaction would be crucial for testing study hypotheses and for early prediction of responders to liraglutide treatment.Embargo status: Restricted until 09/2172. To request the author grant access, click on the PDF link to the left
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
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