1,721,017 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
Loss of prosthetic aortic valve during TAVI procedure: endovascular treatment in emergent setting
No full textINTRODUCTION: Transcatheter aortic valve implantation (TAVI) has proven over the years to be a viable alternative to open surgery. A rare but severe complication is represented by the valve migration. We report a case of TAVI complication due to the loss of the prosthetic valve in the abdominal aorta treated by endovascular approach.METHODS: An 88-year-old patient with severe aortic valve stenosis, symptomatic for dyspnoea was proposed for a TAVI because considered at high risk for surgery. During the TAVI procedure, the undeplyed device (Edwards SAPIEN 3 - Edwards Lifesciences, Irvine, CA, USA) detached from its delivery system. Several attempts to withdraw the valve fluctuating in the aorta into its supporting system were performed without success. An emergency endovascular treatment was promptly planned to obtain the exclusion from the flow of the embolized valve. Under local anaesthesia, through the percutaneous femoral access already present, a tube aortic endograft (EndurantTM II, Medtronic, Santa Rosa, CA; ETTF2828C70EE) was successfully introduced and deployed in the infrarenal aorta without any related complications. The embolized valve was completely covered by the endgraft and thus fixed to the aortic wall. The 1 st post-operative computer tomography angiography (CTA) confirmed the correct placement of the endograft, the exclusion of the valve from the flow and the patency of the great vessels. No perioperative or postoperative complications were recorded. The patient was discharged on the 9th post-operative day with the indication to a new attempt of TAVI, through transapical access.CONCLUSION: In case of intraprocedural loss of an undeplyed valve during TAVI, the valve fixing through endograft deployment in infrarenal aorta is a possible solution
Endovascular Treatment of Abdominal Aorto-Caval Fistula With Occluder Devices: Case Report and Systematic Literature Review
No full text: Aortocaval fistula (ACF) is a life-threatening condition secondary to abdominal aortic aneurysms (AAA) rupture or previous trauma/intervention. The treatment of ACF by an occluder device deployment is a rare but increasingly common approach. We report a case of ACF secondary to ruptured AAA treated with an occluder device after endograft deployment. A 66-year-old male was treated in an emergent setting for a ruptured AAA with ACF deploying aorto-bi-iliac endograft. At 3-month computed tomography angiography (CTA), the persistence of aorto-caval communication and the increased sac reperfusion (type II endoleak) from the lumbar and inferior mesenteric artery were detected. Under local anesthesia and through percutaneous left brachial arterial access and percutaneous right femoral venous access, a 7-mm Amplatzer Septal Occluder was deployed with the "left" atrial end in the aneurysmal sac and the "right" atrial end in the inferior vena cava. The adjunctive embolization of the aneurysmal sac was performed. The post-procedural CTA and 6-month contrast-enhanced ultrasound confirmed the disappearance of endoleak and the exclusion of ACF. A systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was conducted regarding the use of occluder devices to treat ACF (PROSPERO; CRD42024512167). Including the current case, 10 patients (male 100%; age range 24-74 years) in 10 publications were found. ACF after trauma and after AAA rupture was described in 6 and 4 patients, respectively. Occluder device deployment was a primary procedure in 6/10 cases and a secondary intervention in 4/10 cases. Different types of occluder devices (vascular 4/10, atrial septal 3/10, duct 2/10, ventricular septal 1/10) were used. Technical success was 100%, with no intraoperative complications. Postoperative complications occurred in 2/10 patients (vascular plug migration and iliac deep vein thrombosis). Three out 10 patients required reintervention within 30 days for persistent patency of ACF (1 endovascular abdominal aneurysm repair, 1 re-embolization of fistula with coils, 1 patient underwent adjunctive septal occluder device and iliolumbar embolization). In 8/10 patients (length of follow-up: 1-80 months), no residual arterio-venous communication. In 3 patients with AAA, aneurysm shrinkage occurred in 3/3 patients, with type II endoleak in 1 case. Although a scarce number of patients are available in the literature, occluder device deployment into abdominal arterio-venous fistula is feasible. For a traumatic ACF, the occluder device deployment could be proposed as the primary treatment, while, after a ruptured AAA, endograft deployment is mandatory.Clinical ImpactThe use of occluder device for the occlusion of an aorto-caval fistula (ACF) is an off-label technique reported in literature. The technical success mainly depends from the type of deployed occluder device. This treatment should be proposed as first approach in post-traumatic ACF without aneurysms; in case of aneurysmal rupture treated with endograft, the occluder device placement should be considered for persistent endoleak from inferior vena cava
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
Timing and modality of complete revascularization in patients presenting with ST-segment elevation myocardial infarction and multivessel coronary artery disease
No full textApproximately half of the patients presenting with ST-segment elevation myocardial infarction have also significant atherosclerotic disease affecting coronary segments other than the infarct-related artery. Optimal management of residual lesions in this clinical setting has been a topic of intense research in the last decade. On the one hand, a large body of evidence has consistently shown the benefit of complete revascularization for the reduction of adverse cardiovascular outcomes. On the other hand, some crucial aspects such as the optimal timing or the best strategy of the complete treatment approach remain a matter of controversy. In this review, we aim to provide a thorough critical appraisal of the available literature regarding this topic, by discussing areas of relative certainty, gaps in the knowledge, approach to specific clinical subsets and future research directions
Takotsubo cardiomyopathy in an ultra-centenarian woman
No full textA 101 years-old woman was admitted to our Emergency Department (ED) for acute dyspnea which onset nearly two hours before presentation. She had been on hydrochlorothyazyde-amiloride therapy due to mild hypertension. No other relevant features were present in the clinical history. The old lady had never been admitted to the hospital, and she was still living alone. A few days before hospital admission, one of the daughters became ill, so that a caregiver was paid for assisting her 12/24. This new circumstance was reluctantly accepted by the old lady. At ED presentation the patient was dyspnoic but alert. The electrocardiogram showed a marked elevation of the ST segment in V2-V6 leads. The echocardiogram showed the typical apical ballooning, characteristic of takotsubo cardiomyopathy. Blood test only showed a significant increase of cardiac troponin I. Considering the very good conditions of the patient, a coronary angiography was performed, that demonstrated a coronary tree totally free of lesions, thus confirming the clinical suspicion of takotsubo syndrome. The patient was admitted to the Coronary Care Unit, where she had a very good clinical course, and was discharged on day 6th after presentation. After one month of follow-up the clinical course was uneventful and the lady remained in good clinical and lifestyle conditions as before presenting to the ED. This unique case attests that takotsubo cardiomyopathy can be also observed at extreme ages, and should hence be considered in the differential diagnosis of acute dyspnea and chest pain in extremely elderly patients
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