1,720,993 research outputs found
Evaluation of analytical variability of dipstick in identification of proteinuria
No full textEvaluation of proteinuria is essential in dogs with chronic kidney disease and dipstick may give a first rapid and inexpensive estimate. In veterinary medicine no information is available about analytical variability of dipstick test for proteinuria. The aim of this study was to evaluate precision, inter-observer variability and variability between two commercially available dipsticks.
Samples (74 urine supernatants stored at -20°C during a 12-month period) were collected from dogs irrespective of underlying disease. All samples were gently thawed overnight and were assayed for proteinuria with two dipsticks applying urine to the pad by the mean of a dispensable pipette. Two observers evaluated each result. The dipstick evaluation was blinded to the other observer and to the results of the other dipstick. Intra and inter-assay variability of each dipstick were performed by testing 5 samples corresponding to the 5 different semi-quantitative results of the two dipstick for 10 consecutive times and 5 consecutive days, respectively. Variability between observer and between dipsticks was evaluated with Cohen's k test. Analysis was performed for the whole set of results and grouping results as ≤ 1+ and > 2+.
Precision tests showed errors for both operators and both dipsticks. Intra-assay repeatability was good (maximum 3 errors per repeatability), whereas inter-assay variability was higher, ranging from 20% (1/5) to 80% (4/5) of erroneous results, in two cases. When present, errors were found for samples with results between 1+ and 3+. Concordance between operators was good (k = 0.68 and 0.79 for dipstick 1 and dipstick 2, respectively) and improved grouping results in the two classes (k = 0.87 and k = 0.94). Discordance was more frequent at lower results (negative, 1+ and 2+) and one observer overestimated results with both dipstick. Concordance between dipsticks was also good (k = 0.66 and 0.74 for the two operators), rising to 0.83 and 0.90 when results were grouped. Again, errors were more frequent at lower results. Moreover, one dipstick overestimated results for both operator. Errors and discordant results were never higher than one unit in the semi-quantitative scale for both precision and concordance tests.
As any other methods, analytical variability in dipstick evaluation of proteinuria exists. Subjective interpretation of the pad and, to a lesser extent, different responses of different pads could affect sample. Further studies are warranted in order to evaluate the effect of this variability on clinical decision, especially when dipstick is interpreted in association with result of the urinary protein to creatinine ratio or of urine-specific gravity
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
Evaluation of proteinuria in cats: comparison between Coomassie Brilliant Blue and Pyrogallol Red Molybdate
Full text linkPyrogallol Red Molybdate (PRM) is the commonest assay used for evaluation of the concentration of feline urinary protein (UP). The use of Coomassie Brillant Blu (CBB) assay is also reported but data about method-dependent differences and analytical variability are lacking. Therefore, the aims of this study were to compare UPs and urinary protein:creatinine (UPC) ratios recorded with PRM and CBB and to evaluate intra-assay imprecision of creatinine, proteinuria and UPC ratio of both methods in cats.
Urine samples were collected from 58 client-owned cats by ultrasonographically-guided cystocentesis and centrifuged within 30 minutes. Due to the analytical nature of this study, samples were included irrespective of results of sediment or of underlining diseases.
Creatininuria was measured with the modified Jaffè method and UPs with PRM and CBB in triplicate. The mean values were used to calculate UPC ratios. The Wilcoxon signed rank test was performed to investigate the differences between UP obtained with PRR and CBB and between calculated UPC ratios. Correlation between methods was assessed with the Spearman test and agreement with Passing-Bablok and Bland-Altman tests.
Intra-assay coefficients of variations (CV) were calculated in 15 samples by 20 repeated measurements of creatinine and of UPs (with both methods). The Spearman test was used to investigate the correlation between mean UPs and intra-assay CVs for PRM and CBB.
Concordance between UPC ratios of both methods in classifying patients as proteinuric (P, UPC ratio 0,4) was assessed using Cohen’s k coefficient test.
UPs assayed with PRM and CBB ranged from 6,2 to 193,6 mg/dL (median 28,8 mg/dL) and from 8,9 to 325,4 mg/dL (median 61,6 mg/dL), respectively, and creatinine concentration from 28,2 to 934,2 mg/dL (median 199,3 mg/dL).
Proteinuria and UPC ratio showed statistically significant differences between methods (p<0,0001 for both) with higher values recorded using the CBB method. Agreement between methods showed constant and proportional error for protein quantification. The two methods were correlated for both UP and UPC (p<0,0001).
All intra-assay CV were <10%. No correlations were found between the mean UP and the intra-assay CV for both PRM and CBB.
Concordance in classifying samples according to IRIS sub-staging was moderate (k=0,476).
Coomassie Blu method was accurate and precise at any level of proteinuria but the higher UPC obtained with CBB compared to PRM may affect interpretation and clinical decisions according to the IRIS guidelines
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
Big endothelin-1 in cats with CKD : preliminary evaluation
Full text linkIn human medicine the concentration of serum endothelin-1 (ET-1)increases in hypertension and CKD. Also urinary ET-1 correlates withthe severity of renal disease and the magnitude of proteinuria. In dogs,increased concentration of ET-1, evaluated indirectly by the precursorBig Endothelin-1 (big-ET1), seems to be associated with the severityof CKD and hypertension.The aim of this study was to gain information about serum and urinarylevels of big-ET1 in cats with CKD, with and without hypertensionand proteinuria
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