1,720,964 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
Prognostic value of computerized DNA analysis in noninvasive papillary carcinomas of the urinary bladder.
No full textDNA parameters and a DNA status index were calculated in cases of noninvasive urothelial papillary carcinomas and apparently normal urothelium. DNA feature analysis included the measurement of basic parameters as well as those related to DNA deviation. Normal urothelium had a diploid content with a few values between 2c and 4c. The papillary lesions in the three grades showed a progressive decrease in diploid nuclei and steadily increasing percentages of tetraploid ones. One case of grade 1 papillary carcinoma and some of grade 2 showed a small proportion of aneuploid cells; the proportion quintupled in grade 3. The values of parameters related to DNA deviation increased progressively in the three grades, numerically expressing the shift from diploidy. The DNA status index is a multiparameter classification in which a single number, ranging from 0.5 to 3.7, expresses the degree of DNA deviation from a non-proliferating diploid population. The cases of normal urothelium and of grade 1 had the lowest values, from 0.5 to 1.9, whereas grade 3 cases had the highest, from 2.2 to 3.7. The index values of grade 2 cases were partly intermediate and partly in the range of the neighboring grades. The DNA status index has a prognostic significance. In fact, associated lesions and recurrences were only observed in cases with index values over 2.0
Comparison of computerized analysis of nuclear DNA changes in uterine cervix dysplasia and in urothelial non-invasive papillary carcinoma.
No full textThe nuclear DNA content was measured in preneoplastic lesions of the uterine cervix and in papillary carcinomas of the bladder. Three groups of features were calculated from the raw data: basic DNA, DNA deviation and DNA distribution. The basic DNA features, concerning both the cervix and the bladder, showed a progressive increase in the mean DNA content, a decrease in the percentage of diploid nuclei and steadily increasing values of polyploid and aneuploid nuclei. Among the DNA deviation features, the malignancy grade value was zero in the normal cervical epithelium and in the normal urothelium. An increase in this value was evident in moderate dysplasia and in urothelial papillary carcinoma of grade 2, the highest value being in CIS and in grade 3. Concerning the DNA distribution features, the values of the 15th and 95th percentiles and their difference were progressively higher both in the cervix and in the bladder, expressing a continuous shift and spread of the DNA content measurements in the different diagnostic categories, with respect to normal epithelium and urothelium. The statistical analysis showed that the strongest correlation is between 2c D.I. and % of polyploid nuclei in the cervix and between M.I. and % of aneuploid nuclei greater than 4c in the bladder. In the cervix the most discriminating feature is the Malignancy Grade, whereas in the bladder it is the percentage of diploid nuclei. The comparison between the results of the three groups of features showed that: 1) Mild dysplasia of the cervix and urothelial papillary carcinoma of grade 1 showed similar changes in DNA features. Both were basically characterized by increased proliferative activity
Multivariate classifications of transitional cell tumors of the bladder: nuclear abnormality index and pattern recognition analysis.
No full textThe authors report their experiences in applying two types of computer-aided multivariate classification systems in transitional cell tumors of the bladder. The systems are based on nuclear changes in urothelial papillary lesions. 19 out of 54 parameters, selected on the basis of the overlapping area between contiguous grades and the monotonic function, were combined mathematically to obtain the nuclear abnormality index. This index expresses the progressive nuclear abnormalities as a single number on a continuous scale from 0.5 to 2.6. The standard deviation (SD) of the 10 largest nuclear area values in the lower half of epithelial thickness (L), the mean perimeter (L), the SD of the roundness factor in the upper half of epithelial thickness (U), the SD of the logarithm of area (L) and the percentage of round nuclei (U) represent the smallest, the most discriminant and the least correlated set of features for the pattern recognition analysis. The latter shows an agreement of 92% between computer and histologic classifications-estimated by applying Bayes theorem. A good correlation exists between nuclear abnormality index and computer grading by pattern recognition analysis
Cerebrovascular pathology. Comparison of high resolution echography and digital angiography
No full textHistomorphometry and pattern recognition analysis of urothelial papillary lesions.
No full textThe authors report the results of the grading of urothelial papillary carcinoma using histomorphometry and pattern recognition analysis. Features concerning nuclear area, the nuclear roundness factor and inclination angle were measured in 38 cases of urothelial papillary carcinomas. The relative frequency distribution showed overlapping among the grades with a reduction in the practical significance of histomorphometry. To overcome this problem, the pattern recognition analysis was applied. It was found that mean nuclear area, mean roundness factor and percentages of round and horizontal nuclei represent the optimal discriminating set of the subsequent steps in the malignant urothelial transformation
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