1,720,958 research outputs found
Acute posttraumatic rupture of the thoracic aorta : the role of angiography in a 7-year review
No full textBetween 1983 and 1989, 15 patients with acute rupture of the thoracic aorta by blunt trauma were seen. Superior mediastinal widening and obscuration of the aortic arch were the most important findings on chest radiograph. Computed tomography examinations in 7 patients showed mediastinal hematomas but did not reveal aortic lesions. Definitive diagnosis of traumatic aortic rupture was established by aortography in all 15 patients. Intraarterial digital subtraction angiography proved to be as accurate as conventional film aortography and saved time
Rotture traumatiche dell'aorta toracica: revisione dell'esperienza di 10 anni.
No full textWe retrospectively reviewed the diagnostic imaging examinations of 22 patients affected with traumatic rupture of the thoracic aorta acquired in a 10-year period. Our study was aimed at investigating if the diagnostic approach to these patients has changed in the last 10 years, especially relative to the extensive use of Computed Tomography (CT). All the patients in our series were submitted to chest radiography and aortography; only 15 of them were submitted also to CT. Plain radiography showed enlarged mediastinum and altered aortic profiles in 22/22 patients, right-ward deviation of the trachea and nasogastric tube with downward displacement of the left mainstem bronchus and apical cap in 7/22 patients and associated pleuropulmonary injuries in 11 patients. CT image quality was poor because of artifacts in 5 patients, while it demonstrated mediastinal hematoma in 10 patients and associated aortic outline alterations in 5 patients. Aortography always showed the site and number of aortic ruptures. In our experience, aortography should be performed next if chest radiography suggests mediastinal hematoma. CT should be performed before aortography if chest radiography demonstrates no mediastinal hematoma but is not convincingly normal and the patient needs CT studies for associated head and/or abdomen injuries. In this case, if CT is technically correct and its results are normal, aortography needs not be performed, whereas if CT findings are abnormal or not convincingly normal, aortography is mandatory. In the future, the approach to aortic trauma could be modified by transesophageal echocardiography, Magnetic Resonance Imaging and spiral CT, but the results of these imaging methods must still be validated with further extensive studies
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
Tc-99m sulphur colloid scintigraphy in the assessment of residual splenic tissue after splenectomy
No full textDispelling 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
Aneurysm of an aberrant right subclavian artery. Report of a surgically treated case
No full textA 53-year-old man was admitted for treatment of an aberrant right subclavian artery aneurysm that had been diagnosed 5 years earlier and had recently begun to enlarge. The aneurysm, which involved the right subclavian artery from its origin, measured 47 mm in diameter and about 10 cm in length. Because of the lesion's size and friability, a 2-stage operation was performed. In the 1st stage, the right subclavian and right vertebral arteries were revascularized with double bypass grafts via a right cervical approach. In the 2nd stage, the patient was repositioned and a left thoracotomy incision was made. With the aid of left-heart bypass, the aorta was cross-clamped proximal and distal to the lesion, and the aneurysmal orifice was closed with a Dacron patch. The patient was discharged from the hospital on the 17th postoperative day and remains asymptomatic 24 months later. We recommend the 2-stage technique for similar cases because it prevents limb ischemia and reduces the risk of hemorrhagic and embolic complication
- …
