1,721,185 research outputs found
Graphical sensitivity analysis with different methods of imputation for a trial with probable non-ignorable missing data
No full textGraphical sensitivity analyses have recently been recommended for clinical trials with non-ignorable missing outcome. We demonstrate an adaptation of this methodology for a continuous outcome of a trial of three cognitive-behavioural therapies for mild depression in primary care, in which one arm had unexpectedly high levels of missing data. Fixed-value and multiple imputations from a normal distribution (assuming either varying mean and fixed standard deviation, or fixed mean and varying standard deviation) were used to obtain contour plots of the contrast estimates with their?P-values superimposed, their confidence intervals, and the root mean square errors. Imputation was based either on the outcome value alone, or on change from baseline. The plots showed fixed-value imputation to be more sensitive than imputing from a normal distribution, but the normally distributed imputations were subject to sampling noise. The contours of the sensitivity plots were close to linear in appearance, with the slope approximately equal to the ratio of the proportions of subjects with missing data in each trial arm
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
An evaluation of a shared primary and secondary care nephrology service for managing patients with moderate to advanced CKD
No full textBackground: Chronic kidney disease (CKD) is common, and nephrology services may not cope with the comprehensive referral of patients with CKD. We evaluated a shared primary and secondary care nephrology scheme, hypothesizing that some patients with less progressive moderate to advanced CKD can be identified and safely managed without attending the renal unit.Methods: A retrospective review of 949 new referrals with stages 3 to 5 CKD managed in either the hospital nephrology clinic (HC) or the shared care scheme (SCS), in which nephrologists review patients remotely by using regular biochemical tests and clinical data recorded in primary care.Results: Two hundred sixty-six patients (28%) were enrolled in the SCS and 683 patients (72%) were managed solely in the HC. Median time to entering the SCS was 111 days (interquartile range, 0 to 328 days). Baseline factors independently predictive of enrollment in the SCS were increasing age, greater glomerular filtration rate (GFR) and serum albumin levels, and no diabetic nephropathy. Few SCS patients did not attend reviews. Forty-one patients (15%) required recall to the HC, mostly because of a decline in GFR. Beneficial changes were seen in blood pressure levels and prescribing of angiotensin-system inhibitors from first referral to 3 years in all patients. Those enrolled in the SCS had good prognosis, with a lower risk for death or renal replacement therapy than the HC group after adjustment for age, sex, GFR, diabetic nephropathy, and vascular disease (hazard ratio, 0.64; 95% confidence interval, 0.38 to 0.89; P = 0.003).Conclusion: In this setting, it was possible to select nearly 30% of patients with stages 3 to 5 CKD for management in the SCS. More than half enrolled within 4 months of nephrology referral. Systematic surveillance was effective, and most patients remained stable, with few progressing to renal replacement therapy or death
Feasibility of detection and intervention for alcohol-related liver disease in the community: the Alcohol and Liver Disease Detection study (ALDDeS)
No full textBackgroundIn the past 15 years mortality rates from liver disease have doubled in the UK. Brief alcohol advice is cost effective, but clinically meaningful reductions in alcohol consumption only occur in around 1 in 10 individuals.AimTo provide evidence that detecting early liver disease in the community is feasible, practical, and that feedback of liver risk can increase the proportion of subjects reducing alcohol consumption.Design and settingA community feasibility study in nine general practice sites in Hampshire.MethodHazardous and harmful drinkers were identified by WHO AUDIT questionnaire and offered screening for liver fibrosis.ResultsIn total, 4630 individuals responded, of whom 1128 (24%) hazardous or harmful drinkers were offered a liver fibrosis check using the Southampton Traffic Light (STL) test; 393 (38%) attended and test results were returned by post. The STL has a low threshold for liver fibrosis with 45 (11%) red, 157 (40%) amber, and 191 (49%) green results. Follow-up AUDIT data was obtained for 303/393 (77%) and 76/153 (50%) subjects with evidence of liver damage reduced drinking by at least one AUDIT category (harmful to hazardous, or hazardous to low risk) compared with 52/150 (35%, P<0.011) subjects without this evidence; in the subset of harmful drinkers patterns (AUDIT >15), 22/34 (65%) of STL positives, reduced drinking compared with 10/29 (35%, P<0.017) STL negatives.ConclusionDetection of liver disease in the community is feasible, and feedback of liver risk may reduce harmful drinking
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
p53 pathway gene single nucleotide polymorphisms and chronic lymphocytic leukemia
No full textThe p53 pathway plays a critical role in chronic lymphocytic leukemia (CLL). The association between the single-nucleotide polymorphism (SNPs) within the p53 gene (R72P) and its downstream target/regulators, BAX (G125A) and MDM2 (SNP309), and clinical parameters/prognostic markers was investigated in 83 CLL patients. Although the p53 R72P SNPs and MDM2 SNP309 did not associate with any of the parameters studied, the BAX G125A SNPs was associated with a more advanced Binet stage at diagnosis, supporting a potential role for this variant in CLL disease progression. In reporter assays, however, the BAX 5' untranslated region G125A SNPs surprisingly caused a 1.8-fold increase in basal promoter activity and did not alter the ability of p53 to transactivate the promoter. Further studies are required to understand the role of SNPs in the p53 pathway in CLL
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