1,721,005 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
Influence of radiotherapy on long-term follow-up of clinically non-secreting pituitary adenomas
No full textOBJECTIVE:
We wished to evaluate the influence of postoperative radiotherapy on the incidence of tumour regrowth in non-secreting pituitary adenomas.
METHODS:
The cases of 57 patients with clinically non-secreting pituitary adenomas were retained for a retrospective study of long-term disease-free survival out of a series of 66 patients treated between 1970 and 1988. Thirty-three patients were treated by surgery only (Group A), and twenty-four by surgery followed by external radiotherapy (Group B). Disease-free survival curves were calculated according to the Kaplan-Meyer method and compared by the Logrank test. The impact of some supposed prognostic parameters--such as tumoural volume, macroscopic features of invasiveness and quality of surgical resection--on the disease-free survival was analyzed according to the Logrank adjusted test.
RESULTS:
The mean follow-up duration was 7.1 +/- 6.2 years, and eleven patients relapsed: nine in group A (27.0%) and two in group B (8.3%), with respective free intervals of 6.1 +/- 5.0 years and 9.6 +/- 2.4 years. Statistical analysis of the disease-free survival curves confirmed that this difference was significant (p < 0.01). Further analysis of putative risk factors (the importance of extrasellar extension and the estimated quality of surgical resection) was attempted, but it did not reach statistical significance.
CONCLUSIONS:
Radiotherapy is effective in preventing post-operative regrowth of non-secreting pituitary adenomas. Whether it should be systematically proposed or reserved to selected cases remains to be evaluated
THORACOSCOPIC REMOVAL OF MEDIASTINAL PARATHYROID GLANDS. A CRITICAL APPRAISAL OF AN EMERGING TECHNIQUE.
No full textObjective: To retrospectively evaluate the feasibility of thoracoscopic removal of mediastinal parathyroids. SUMMARY BACKGROUND DATA Mediastinal exploration to resect ectopic parathyroid(s) is needed in approximately 2% of cases in hyperparathyroidism. Recent advances in thoracoscopic surgery allow for a minimally invasive treatment. Methods: From 1999 through 2007, 13 patients affected by primary hyperparathyroidism (11 females, mean age 60 years, range: 22-88) underwent thoracoscopic removal of mediastinal parathyroids. Scintigraphy produced positive Results: in 11 of 13 cases, computed tomography scan in 9 of 10, parathyroid hormone venous sampling in 10 of 10 patients, and magnetic resonance imaging in 5 of 7. Right thoracoscopic access was used in 9 patients, left in 4. Postoperative outcome was analyzed. Results: Thoracoscopy enabled retrieval of mediastinal parathyroids in 10 of 13 (78%) cases. Mean operating time was 92 minutes (range: 50-240). One procedure (8%) was converted. No perioperative deaths/major complications occurred. Mild complications occurred in 2 of 13 (15%) patients (pneumothorax/pneumonia, transient recurrent nerve palsy). Mean hospital stay was 4.7 days (range: 2-15). At a mean follow-up of 73 months (range: 16-105), parathyroid hormone and calcium venous concentrations were high in 3 patients. Unsuccessful procedures were related to doubtful or non-concordant preoperative localization. Conclusion:S The thoracoscopic approach for mediastinal parathyroidectomy is feasible and safe. An accurate preoperative work-up should be standardized to avoid useless procedures. In case of negative preoperative localization of the abnormal gland, thoracoscopy should not be adopted as a diagnostic too
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
- …
