1,721,003 research outputs found
Aortoiliac stent graft infection: Current problems and management
No full textAortic stent graft infection is uncommon. Most cases have been described anecdotaly in single-case reports. After observing one case in our experience, we decided to review the literature and contact centers performing endovascular aortic repair to determine the frequency, risk factors, and current treatment of stent graft infection. The literature was reviewed and the authors of identified articles were contacted for further information. In addition, 40 centers specializing in endovascular treatment were contacted by means a dedicated questionnaire. A total of 65 aortic stent graft infections were identified, including 43 reported cases and 22 previously unpublished cases that were observed at specialized centers. Stent grafts were implanted in the aorta in 50 cases and in the iliac artery in 15 cases. The frequency of infection was 0.43%. The gender ratio was 4:1 (M:F). Twenty-three percent of patients had immunodeficiency factors. Placement was performed in an interventional radiology suite in 62.5% of cases and in a sterile operating theater in 37.5%. Also, 35.5% of patients underwent other vascular procedures during the course of study and 29.2% stent grafts benefited from adjuvant endovascular procedures. Infection was classified as low grade in 35.4% of patients and high grade in 64.6%. Thirty-one percent of infections were associated with aortoenteric fistula. The offending microorganism was Staphylococcus aureus in 54.5% of cases. Treatment was conservative in 18% of cases and surgical in 82%. Surgical treatment consisted of stent graft removal followed by either extraanatomical bypass (59.5%) or in situ prosthetic reconstruction (40.5%). Mortality was 18% overall, 36.4% after conservative treatment and 14% after surgical treatment (p=0.083). Mortality was 16% after surgical treatment with extraanatomical bypass vs. 5.8% surgical treatment with in situ reconstruction. From these results we conclude that stent graft infection is an uncommon occurrence associated with poorly defined risk factors. Surgical treatment with complete excision of the infected stent graft followed by in situ reconstruction provides the best outcome. Establishment of a multicenter register to record such complications is needed to confirm the findings of this study
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
Pulvérisation ultrasonique dans un turboréacteur
No full textCe projet s’ancre dans le cadre du programme INCA (Initiative en Combustion Avancée)
issu d’une collaboration entre la Snecma, l’Onera et le CNRS. L’objectif final est de développer un
démonstrateur de technologie pour réaliser l’injection du carburant dans un turboréacteur à l’aide
d’ultrasons. Le projet s’appui sur les travaux réalisés depuis 2006. L’étude présentée est centrée sur
l’amélioration du modèle numérique par la modélisation de l’actionneur piézoélectrique et à la
détermination des coefficients viscoélastiques du titane. Dans le cadre de la collaboration avec
l’Onera, Sonotron a mis en place un banc d’essais qui permet d’appliquer une vibration sur un sabot
en plexiglas en excitant l’écoulement qui se déplace au dessus. Finalement, la transmission
d’ultrasons de puissance à travers une sonotrode courbée est étudiée dans la dernière partie de ce
projet.Outgoin
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
Pulvérisation ultrasonique dans un turboréacteur
No full textCe projet s’ancre dans le cadre du programme INCA (Initiative en Combustion Avancée)
issu d’une collaboration entre la Snecma, l’Onera et le CNRS. L’objectif final est de développer un
démonstrateur de technologie pour réaliser l’injection du carburant dans un turboréacteur à l’aide
d’ultrasons. Le projet s’appui sur les travaux réalisés depuis 2006. L’étude présentée est centrée sur
l’amélioration du modèle numérique par la modélisation de l’actionneur piézoélectrique et à la
détermination des coefficients viscoélastiques du titane. Dans le cadre de la collaboration avec
l’Onera, Sonotron a mis en place un banc d’essais qui permet d’appliquer une vibration sur un sabot
en plexiglas en excitant l’écoulement qui se déplace au dessus. Finalement, la transmission
d’ultrasons de puissance à travers une sonotrode courbée est étudiée dans la dernière partie de ce
projet.Outgoin
Pulvérisation ultrasonique dans un turboréacteur
No full textCe projet s’ancre dans le cadre du programme INCA (Initiative en Combustion Avancée)
issu d’une collaboration entre la Snecma, l’Onera et le CNRS. L’objectif final est de développer un
démonstrateur de technologie pour réaliser l’injection du carburant dans un turboréacteur à l’aide
d’ultrasons. Le projet s’appui sur les travaux réalisés depuis 2006. L’étude présentée est centrée sur
l’amélioration du modèle numérique par la modélisation de l’actionneur piézoélectrique et à la
détermination des coefficients viscoélastiques du titane. Dans le cadre de la collaboration avec
l’Onera, Sonotron a mis en place un banc d’essais qui permet d’appliquer une vibration sur un sabot
en plexiglas en excitant l’écoulement qui se déplace au dessus. Finalement, la transmission
d’ultrasons de puissance à travers une sonotrode courbée est étudiée dans la dernière partie de ce
projet.Outgoin
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