117,423 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Carotid artery dissection
No full textCarotid dissection may be spontaneous, traumatic or iatrogenic. The incidence of this disease is very low. Carotid dissection is a rare cause of ischemic stroke and the instrumental diagnosis includes conventional angiography, magnetic resonance imaging, ultrasound techniques and helical computed tomography angiography. Anticoagulant therapies are recommended for all the patients regardless by dissection's aetiology in order to prevent thromboembolic complications. Options for open surgical repair include resection of the involved segment with interposition of vein graft, thromboendarterectomy and patch closure, extracranial to intracranial carotid artery bypass, gradual dilation of the carotid artery and ligation of the cervical carotid artery. More recently endovascular techniques have been used to treat high-grade stenosis and aneurysmal dilatation as a consequence of a carotid dissection. No evidence exists about the benefits of one technique than the others. In any case, surgical or endovascular treatment should be reserved for patients who have persistent symptoms of ischemia despite adequate anticoagulation. In this report we review recent new knowledges in epidemiology and pathogenesis of carotid artery dissection, paying particular attention to clinical manifestations, methods of diagnosis and kinds of treatment
Surgical management of popliteal artery aneurysms: Which factors affect outcomes?
No full textObjective: Popliteal artery aneurysm (PAA) is uncommon. The clinical presentation of PAA includes rupture, embolism, and thrombosis. In this article, we evaluate the results of our 20-year experience with surgical management of PAAs, analyzing the role of anatomic, clinical, and surgical factors that potentially affect early and long-term results. Methods: From January 1984 to December 2004, 159 PAAs in 137 patients were operated on at our department. Data from all the patients were retrospectively collected in a database. PAAs were asymptomatic in 67 cases (42%); 5 (3%) PAAs were ruptured. In 51 cases (32%), PAA caused intermittent claudication. The remaining 36 limbs (23%) had threatening ischemia due in 30 cases to acute PAA thrombosis, in 4 cases to chronic PAA thrombosis, and in 2 cases to distal embolization. In selected patients with acute ischemia, preoperative intra-arterial thrombolysis with urokinase was performed. Early results in terms of mortality, graft thrombosis, and limb salvage were assessed. Follow-up consisted of clinical and ultrasonographic examinations at 1, 6, and 12 months and yearly thereafter. Long-term survival, patency, and limb salvage rates were analyzed. Results: Forty cases were treated with aneurysmectomy and prosthetic graft interposition; in 39 cases, the aneurysm was opened, and a graft was placed inside the aneurysm. Four patients had aneurysmectomy with end-to-end anastomosis. In 73 cases, ligation of the aneurysm with bypass grafting (39 with a prosthetic graft and 34 with an autologous vein) was performed. The remaining three patients underwent endovascular exclusion of their PAAs. A medial approach was used in 97 patients (61%), and a posterior approach was used in 59 patients (37.1%). The outflow vessel was in most cases (93.7%) the below-knee popliteal artery. Thirty-day amputation and death rates were 4.4% (7/159 limbs) and 2.1% (3/137 patients), respectively. The amputation rate was significantly higher in symptomatic limbs than in asymptomatic ones (6.5% and 1.4%, respectively; P = .05). Eight limbs (5%) had an early graft thrombosis that required a reintervention. Follow-up was available in 116 patients (84.7%) and 138 limbs (86%) with a mean follow-up time of 40 months (range, 1-205 months). The cumulative estimated 60-month survival, limb salvage, and primary and secondary patency rates were 84.2%, 86.7%, 66.3%, and 83.6%, respectively. Asymptomatic limbs had significantly better results than symptomatic ones in terms of limb salvage (93.4% and 80.4%, respectively; P = .03; log-rank, 4.2) and primary patency (86.5% and 51.6%, respectively; P = .001; log-rank, 10.3). Among symptomatic patients, results were better in claudicant limbs than in acutely ischemic ones in terms of limb salvage (90.5% and 58.7%, respectively; P = .001; log-rank, 17.5). Univariate analysis showed the absence of symptoms, the presence of two or three tibial vessels, the use of a posterior approach, the kind of intervention, and the site of distal anastomosis to significantly affect long-term patency. Cox regression for factors affecting 60-month primary patency showed that clinical presentation, runoff status, and the site of distal anastomosis significantly influenced long-term results. Conclusions: Results of surgery on asymptomatic PAAs are good - significantly better than those for symptomatic ones. Elective surgical intervention should be performed in patients with a low surgical risk and a long life expectancy when the correct indication exists. In thrombosed aneurysms, intra-arterial thrombolysis may represent an alternative to emergent surgical management. Our data demonstrated that results are similarly good in claudicants, and this fact confirms that only acute ischemia due to PAA thrombosis represents a real surgical challenge. In selected patients with focal lesions, a posterior approach seems to offer better long-term results. The runoff status and the site of distal anastomosis affect long-term patency as well. Copyright © 2006 by The Society for Vascular Surgery
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
The Treatment of Isolated Iliac Artery Aneurysm in Patients with Non-aneurysmal Aorta
No full textObjectives: The aim of the study was to evaluate early and mid-term results of surgical repair of isolated iliac artery aneurysm (IAA) in patients with non aneurysmal abdominal aorta. Methods: From January 1996 to December 2006, 34 patients with IAA had elective surgery. In 32 cases open repair was performed. Two patients had endovascular repair using a tube endoprosthesis and internal iliac artery coil embolization. The diameters of the abdominal aorta and iliac arteries were measured preoperatively and during follow-up. Early and late results in terms of mortality, major morbidity, reinterventions and graft-related complications were recorded. Mean pre and postoperative diameters of abdominal aorta were compared. Results: The site of the IAA was the common iliac artery in 29 cases (10 bilateral), internal iliac artery in 4 cases and external iliac artery in 1 case. Preoperative mean abdominal aortic diameter was 22.2 mm (SD 7.6). There were no perioperative deaths and two major complications (retroperitoneal bleeding and limb ischemia) occurred. At the median follow-up time of 24 months survival was estimated as 91%. No reinterventions, graft thrombosis and graft related complications occurred. There were no cases of abdominal aorta aneurysm development. Mean aortic diameter at the most recent imaging was 23.1 mm, which was not significantly different from preoperative values (p = 0.2). Conclusions: Surgical treatment of IAAs provides good early and mid-term results. During mid-term follow-up the diameter of abdominal aorta remains stable, suggesting IAA may be a localized aneurysmal disease. © 2007 European Society for Vascular Surgery
Early and mid-term results of kissing stent technique in the management of aorto-iliac obstructive disease
No full textTo retrospectively analyze early and mid-term results of endovascular management of aorto-iliac obstructive disease with the kissing stent technique
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
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