1,720,967 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
Post-implantation syndrome after endovascular aortic repair using The AnacondaTM endograft
No full textBACKGROUND:
We report our retrospective experience on postimplantation syndrome (PIS) after the use of AnacondaTM endograft in patients undergoing elective endovascular repair of abdominal aortic aneurysms (EVAR).
METHODS:
Data of all patients undergoing elective EVAR between May 2000 and June 2013 using the Anaconda endograft were retrospectively reviewed and the outcomes were analyzed. Preoperative and intraoperative data, any early postoperative complications, length of in-hospital stay, incidence of PIS, and long-term complications were recorded in a database. Patients' quality of life (QOL) was also assessed at 1 month after the procedure. Statistical analysis was performed and P values ≤0.05 were considered statistically significant. Chi-squared tests, log-rank tests, Wilcoxon tests, and Kaplan-Meier survival analysis were performed as appropriate.
RESULTS:
Between May 2000 and June 2013, 118 patients (8 female, 6.7%) underwent elective EVAR using the Anaconda endograft. Primary success was obtained in 117 cases (99.1%). Patients were divided into 2 groups based on either the occurrence of PIS (group A: 24 patients, 20.3%) or not (group B). The length of the procedure and the in-hospital stay were longer for group A. One patient from group B died on second postoperative day from myocardial infarction (0.8%). Mean follow-up was 48.4 months (range 5-162 months). Seven endoleaks occurred in the long term regardless of the development of PIS. We did not find any correlation between the presence of PIS and the occurrence of long-term complications, but PIS was correlated to the preoperative burden of thrombus of the aneurysmal sac. On the other side, analysis of QOL surveys showed that patients who had PIS after surgery felt significantly more limited in carrying out their daily physical activities and were more emotionally discouraged and depressed/anxious about their state of health than the group that did not have PIS.
CONCLUSIONS:
In our experience, the occurrence of PIS was related to the duration of the procedure and the preoperative burden of thrombus of the aneurysmal sac. Overall, PIS was a benign complication after EVAR using the Anaconda endograft. However, it affected significantly the length of the in-hospital stay. Moreover, patients who had PIS after surgery felt significantly more limited in carrying out their daily physical activities and were more emotionally discouraged and depressed/anxious about their state of health than the group that did not have PIS
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
Straight aortic endograft in abdominal aortic disease
Full text linkBackground: We describe our 8-year experience with the use of endovascular techniques (ET) for the treatment of abdominal aortic aneurysms (AAA) through a straight endograft.
Methods: We retrospectively reviewed data of all patients who were treated for AAA using ET in two centres from 1998 to 2012 and who received a single straight endograft (group A) or a double straight tube (group B). Outcomes were analyzed to assess survival, absence of endoleak and absence of reintervention for both groups. Log-rank and Chi-Square were used as appropriate to make comparison between the two groups. P values <.05 were considered statistically significant.
Results: Fifty-three patients from 1998 to May 2012 were treated for AAA using a straight endograft. In 28 cases (52.8%) a single aortic straight tube was used (Group A), while in the remaining cases a "double trombone technique" was used (Group B). Primary success was obtained in 52 cases (98.1%). In one patient of group A immediately after the operation we observed a type Ia endoleak, which was correct with a proximal aortic cuff. Fluoroscopy time, operation time, amount of intraprocedural contrast medium and blood loss were slightly higher for group B, even if not significantly. Mortality at 30 days was nil for both groups. Mean follow-up was 49 months (range 2-153 months). Five patients died in group A, four of them for a neoplastic disease and the remaining for aortic rupture. No patients died in group B. Endoleaks occurred more frequently in patients of group A (5 type I endoleaks and 1 type II endoleak from a lumbar artery). Reintervention were more frequent for patients of group A, being type I endoleak the main cause. A stent fracture was observed in a patient who received EVAR by "trombone technique" 3 months later. Reintervention was then necessary and a third stent was successfully placed to cover the lesion.
Conclusions: In our experience the endovascular repair of AAA using straight aortic endografts was a safe and effective technique. Reintervention and endoleaks were slightly more frequent in patients who had received a single endograft compared to patients who were treated using the "trombone technique"
Early experience with ovation endograft system in abdominal aortic disease
Full text linkObjective: We describe our initial experience with the use of the TriVascular Ovation endograft system for the treatment of abdominal aortic aneurysms (AAA) .Methods: We retrospectively reviewed data from patients treated for AAA using the Ovation endograft at two institutions from January 2011 to September 2012. Main outcomes included primary success, survival, complications, and device-related events. The mean follow-up period was 10 months (range 1-22 months). Results: Thirty-seven patients (male: 95%, mean age: 76 yr) were treated for AAA (mean diameter: 54 mm) with the Ovation endograft. Local or regional anesthesia was used in 86.5% of cases. Percutaneous access was utilized in 73% of cases. Primary success was 89.2% (33/37). Four adjunctive procedures were required including two distal extensions (type 1b endoleak and iliac limb disconnection resulting in type III endoleak) and two bypass surgeries (limb graft occlusion and gate cannulation failure). No deaths or major complications were reported during the procedure or in follow-up. No type I, III, or IV endoleak, AAA enlargement, AAA rupture, stent fracture, migration, or endovascular or surgical reintervention were reported during the follow-up period. Type II endoleak was observed in two patients. Asymptomatic narrowing of both iliac limbs was observed in one patient at 6 months. Conclusions: Our initial experience with the Ovation endograft demonstrated encouraging results in patients with AAA
- …
