1,720,959 research outputs found
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
Controlled attenuation parameter for evaluating liver steatosis in chronic viral hepatitis.
No full textTo assess the performance of controlled attenuation parameter (CAP) in patients with chronic viral hepatitis.CAP is a new technique that measures the attenuation in the liver of an ultrasound beam, which is directly related to lipid accumulation. Consecutive patients undergoing liver biopsy for chronic viral hepatitis were studied using the M probe of FibroScan device (Echosens, Paris, France). The device estimates liver steatosis in decibel per meter (dB/m). An expert operator performed all measurements. Steatosis was graded according to Kleiner's classification. Pearson or Spearman rank coefficient was used to test correlation between two study variables. Linear regression was used for multivariate model to assess the association between CAP and other variables. Receiver operating characteristic curve analysis was performed to calculate area under the curve (AUROC) for S0 vs S1-S3 and S0-S1 vs S2-S3.115 subjects (85 males and 30 females) were prospectively studied. The mean values of CAP were 227.1 ± 43.1 for S0; 254.6 ± 38.9 for S1; 297.8 ± 49.4 dB/m for S2-S3. In univariate analysis CAP showed a significant correlation with age, body mass index (BMI), degree of steatosis, and cholesterol. Multivariate regression analysis confirmed the correlation with the degree of steatosis [coefficient, 1.2 (0.60-1.83); P < 10(-5)] and BMI [coefficient, 4.1 (0.5-7.8); P = 0.03] but not with all other variables. Optimal cutoff values for S ≥ 1 and S ≥ 2 were 219 dB/m [AUROC, 0.76 (0.67-0.84); sensitivity, 91.1\% (78.8-97.5); specificity, 51.6\% (38.7-64.2); positive predictive value, 56.9\% (44.7-68.6); negative predictive value, 89.2\% (74.3-97.0); positive likelihood ratio, 1.88 (1.4-2.5); negative likelihood ratio, 0.17 (0.07-0.5)] and 296 dB/m [AUROC, 0.82 (0.74-0.89); sensitivity, 60.0\% (32.3-83.7); specificity, 91.5\% (83.9-96.3); positive predictive value, 52.9\% (27.8-77.0); negative predictive value, 93.5\% (86.3-97.6); positive likelihood ratio, 7.05 (3.2-15.4); negative likelihood ratio, 0.44 (0.2-0.8)], respectively.Controlled attenuation parameter could be a useful tool in the clinical management of patients with chronic viral hepatitis for detecting liver steatosis
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
Placental histopathological correlates of umbilical artery Doppler velocimetry in pregnancies complicated by fetal growth restriction.
No full textThe objective of the study was to evaluate the association between placental histological patterns and umbilical artery (UA) Doppler velocimetry in pregnancies complicated by fetal growth restriction (FGR).A cohort of 126 FGR pregnancies was followed according to a standard protocol. Placental lesions were diagnosed according to consensus nomenclature and standardized criteria.Pulsatility index was normal in 45 (35.7\%) and increased in 44 (34.9\%) women. End-diastolic UA Doppler flow was absent in 27 (21.4\%) and reversed in 10 (7.9\%). Fifty-four women (42.9\%) had preeclampsia. In preeclampsia, increasing Doppler abnormalities, from normal to reversed UA end-diastolic flow, were directly associated only with an increased number of placental syncytial knots. In normotensive pregnancies, Doppler abnormalities were associated with increased intervillous fibrin deposits, villous hypoplasia, syncytial knots, placental site giant cells, immature intermediate trophoblast, and with pattern of lesions indicating superficial implantation and maternal vascular underperfusion. In the whole cohort, increase of syncytial knots [odds ratio (OR) = 28.7; 95\% confidence interval (CI) = 2.75-298.5], intervillous fibrin deposits (OR = 2.1; 95\% CI = 1.04-4.28), placental site giant cells (OR = 3.0; 95\% CI = 1.05-8.84), and patterns suggesting maternal underperfusion (OR = 2.9; 95\% CI = 1.0-7.1) were independently associated with increased rates of absent/reversed UA end-diastolic flow.In pregnancies complicated by FGR, abnormalities of UA Doppler velocimetry were associated with placental lesions indicating superficial implantation and maternal vascular underperfusion
Point shear wave elastography method for assessing liver stiffness.
No full textTo estimate the validity of the point shear-wave elastography method by evaluating its reproducibility and accuracy for assessing liver stiffness.This was a single-center, cross-sectional study. Consecutive patients with chronic viral hepatitis scheduled for liver biopsy (LB) (Group 1) and healthy volunteers (Group 2) were studied. In each subject 10 consecutive point shear-wave elastography (PSWE) measurements were performed using the iU22 ultrasound system (Philips Medical Systems, Bothell, WA, United States). Patients in Group 1 underwent PSWE, transient elastography (TE) using FibroScan (Echosens, Paris, France) and ultrasound-assisted LB. For the assessment of PSWE reproducibility two expert raters (rater 1 and rater 2) independently performed the examinations. The performance of PSWE was compared to that of TE using LB as a reference standard. Fibrosis was staged according to the METAVIR scoring system. Receiver operating characteristic curve analyses were performed to calculate the area under the receiver operating characteristic curve (AUC) for F ≥ 2, F ≥ 3 and F = 4. The intraobserver and interobserver reproducibility of PSWE were assessed by calculating Lin's concordance correlation coefficient.To assess the performance of PSWE, 134 consecutive patients in Group 1 were studied. The median values of PSWE and TE (in kilopascals) were 4.7 (IQR = 3.8-5.4) and 5.5 (IQR = 4.7-6.5), respectively, in patients at the F0-F1 stage and 3.5 (IQR = 3.2-4.0) and 4.4 (IQR = 3.5-4.9), respectively, in the healthy volunteers in Group 2 (P < 10(-5)). In the univariate analysis, the PSWE and TE values showed a high correlation with the fibrosis stage; low correlations with the degree of necroinflammation, aspartate aminotransferase and gamma-glutamyl transferase (GGT); and a moderate negative correlation with the platelet count. A multiple regression analysis confirmed the correlations of both PSWE and TE with fibrosis stage and GGT but not with any other variables. The following AUC values were found: 0.80 (0.71-0.87) for PSWE and 0.82 (0.73-0.89) for TE (P = 0.42); 0.88 (0.80-0.94) for PSWE and 0.95 (0.88-0.98) for TE (P = 0.06); and 0.95 (0.89-0.99) for PSWE and 0.92 (0.85-0.97) for TE (P = 0.30) for F ≥ 2, F ≥ 3 and F = 4, respectively. To assess PSWE reproducibility, 116 subjects were studied, including 47 consecutive patients scheduled for LB (Group 1) and 69 consecutive healthy volunteers (Group 2). The intraobserver agreement ranged from 0.83 (95\%CI: 0.79-0.88) to 0.96 (95\%CI: 0.95-0.97) for rater 1 and from 0.84 (95\%CI: 0.79-0.88) to 0.96 (95\%CI: 0.95-0.97) for rater 2. The interobserver agreement yielded values from 0.83 (95\%CI: 0.78-0.88) to 0.93 (95\%CI: 0.91-0.95).PSWE is a reproducible method for assessing liver stiffness, and it compares with TE. Compared with patients with nonsignificant fibrosis, healthy volunteers showed significantly lower values
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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