1,721,063 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
Forced Complete Femoral Approach for Urgent Thoracoabdominal Aneurysm Repair Using an Inner Branched Endograft
No full textBackground: A successful case of urgent type II thoracoabdominal aneurysm repair with an inner branched endograft conducted entirely through femoral accesses without the bailout possibility to achieve an upper extremity approach for bridging stents delivery is described. Case report: A 70-year-old male patient underwent hybrid treatment for a thoracic aortic aneurysm on complicated type B dissection in 2 steps. First, arch debranching with carotid-carotid-subclavian bypass and then ascending aortic replacement with reimplantation of the anonymous trunk plus TEVAR were performed. The scheduled 1-month control computed tomography angiography (CTA) showed a rapid increase of the false lumen thoracoabdominal aneurysm, with axial diameter measuring more than 10 cm. The repair procedure was based on the use, as off-the-shelf graft, of a prosthesis customized for another patient with inner branches for visceral vessels that well suited the characteristics of the case. A steerable guiding sheath was essential to stabilize the system in the selective and sequential cannulation of 2 of the 4 inner branches (for celiac trunk and superior mesenteric artery) and to complete the bridging stents deployment. Procedure was carried out without complications. Conclusions: In an urgent setting, total endovascular correction of a thoracoabdominal aortic aneurysm exclusively through femoral accesses appears to be feasible when the appropriate tools are available
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
Rotational Mechanical Thrombectomy to Treat Iliac Limb Occlusion after Endovascular Aortic Aneurysm Repair: The Rotational Mechanical Thrombectomy Italian Study
No full textPurpose: To assess the safety and effectiveness of a rotational mechanical atherothrombectomy device in patients with symptomatic iliac limb occlusion after abdominal endovascular aneurysm repair (EVAR). Materials and methods: A retrospective analysis was conducted on patients who underwent rotational mechanical thrombectomy using the Rotarex S device for symptomatic acute, subacute, or chronic graft limb thrombosis at 5 vascular centers between 2017 and 2021. This study comprised 23 male patients with a mean age of 74.5 years (SD ± 7.2) at the time of the procedure. The clinical presentation of the patients varied, with 1 patient experiencing acute limb ischemia and 11 patients (47.8%) experiencing disabling intermittent claudication. The remaining patients developed chronic limb-threatening ischemia after iliac limb occlusion. Early outcomes included technical success, postprocedural complications, and periprocedural mortality. Follow-up evaluations encompassed primary patency, patient survival, freedom from reintervention, and the need for surgical conversion. Results: Technical success was achieved in all cases, with no occurrences of distal embolization during or after the procedure, and no periprocedural deaths were reported. Endograft relining was performed in 82.6% of patients to establish a new, nonthrombogenic surface within the graft. Over a median follow-up period of 8 months (interquartile range, 3-16 months), 2 patients experienced iliac limb reocclusion. No deaths or other reinterventions occurred during the observational follow-up period. Conclusions: Rotational mechanical thrombectomy for iliac limb occlusion after EVAR appears to be both safe and effective. This technique may uncover intraluminal defects contributing to graft occlusion and enable their resolution within the same procedure
Comparison of bridging stent grafts in branched endovascular aortic repair
No full textBackground: Endovascular treatment of thoracoabdominal aortic aneurysms has become common, with satisfactory results. Nevertheless, long-term durability remains an issue mainly because of target visceral vessel (TVV) instability. Currently, no covered stent has been approved as a bridging stent graft (BSG), demanding continuous research on this topic. Methods: This was a multicenter observational retrospective cohort study comparing the midterm results of the Bard Covera Plus and Gore VBX as BSGs during branched endovascular aneurysm repair. The primary outcome was the comparison of the target vessel instability between the two groups. Primary patency, freedom from branch-related type I and III endoleaks and reintervention, and technical and clinical success were considered secondary outcomes. Logistic regression analysis was used to assess the association between selected baseline factors and TVV instability. TVV instability during follow-up was then evaluated using the Kaplan-Meier cumulative function. Results: Three hundred forty-five TVVs in 106 patients were considered suitable for the analysis. Two hundred twenty vessels were stented with the Covera stent graft (64%) and 125 with VBX (36%). Two hundred ninety-nine TVVs received a single BSG, 45 two BSGs, and only 1 three BSGs. Bare metal stent relining was required in 36% of TVVs, mostly in the Covera group (89 [41%] vs 36 [29%]) (P =.030). The primary technical success rate was 96% (331/345), and the assisted primary technical success rate was 99% (342/345). The TVV instability rate within 30 days was 2% (one Covera and five VBX; P =.015). Three BSG occlusions (one Covera and two VBX) and three type Ic endoleaks (three VBX) were detected. The median follow-up was 13.9 months (range, 5.8-25.5 months). Sixteen TVV instabilities were detected during the follow-up. Twelve BSG occlusions (six Covera and six VBX), three type Ic endoleaks (one Covera and two VBX), and one type IIIc endoleak (VBX). The overall target vessel instability rate was 5% (16/342). TVV instability was associated with the use of Gore VBX in the univariable logistic regression (odds ratio, 3.0; 95% confidence interval, 1.1-8.0; P =.027). Aneurysm rupture and aneurysm diameter were also associated with TVV instability in the univariable analysis (P =.002 and P =.008, respectively). The only factor predisposing to TVV instability in the multivariable logistic regression analysis was the use of Gore VBX as a BSG (odds ratio, 2.9; 95% confidence interval, 1.0-8.0; P =.043). Kaplan-Meier analysis showed a significantly higher risk of TVV instability in the VBX group (P <.001). Conclusions: Overall midterm outcomes in this cohort were satisfactory. Patency rates were similar between the two stents. Nevertheless, VBX seems to be associated with worse TVV instability. These results may be correlated with a higher incidence of type Ic endoleaks, which require an extensive learning curve for correct stent selection and deployment
Comparison of battery string parallelization systems to improve Na-NiCl2 battery reliability
No full textThe Sodium-Metal Halide Battery reliability should be increased to enhance the competitiveness of this technology in the stationary battery market alongside lithium-ion and lead-acid batteries. Currently, the elementary Sodium-Metal Halide cells show a rather low reliability. Commercial battery power management systems are not able to completely use the energy stored if a battery composed of multiple parallel-connected strings presents faulty cells. In fact, the string parallelization is generally achieved by ideal diode circuits that do not allow the optimal management of the strings in faulty conditions. As an example, the reliability of the 48TL200 FZSoNick battery composed of 5 strings of 20 cells each is estimated to be lower than 30% after 10 working years. Two novel string parallelization approaches are compared to the commercial diode-based solution in this work. The first approach employs DC/DC converters and shows the best performances increasing the battery reliability near to 100% at the cost of higher battery cost and complexity. The second approach replaces the diodes with controllable switches. The switches increase the battery reliability beyond 95% with little increase of the battery complexity and cost
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