1,721,009 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
Circumferential fusion of the lumbar and lumbosacral spine using a carbon fiber ALIF cage implant versus autogenous bone graft: A comparative study
No full textThis study reports on 92 patients treated with circumferential lumbar fusions for degenerative conditions. The elected procedure was a circumferential fusion using transpedicular stabilization. Two groups were examined depending on whether they were stabilized anteriorly with autogenous bicortical iliac crest graft (n = 38) or with an ALIF carbon fiber cage implant (n = 54). The patients were evaluated for clinical and radiographic outcome. The minimum follow-up interval was at least 12 months. Fusion rates, postoperative loss of correction, and clinical results, including pain at the bone donor site, neurologic function, satisfaction, depression, and consumption of analgesics, were not significantly different between patients with autogenous bone graft and patients with carbon cage. This study failed to prove major advantages of the carbon cages in the clinical and radiologic outcome
Pericardial tamponade during installation of a central venous catheter
No full textA case report demonstrates the complication of pericardial tamponade during the installation of a central venous catheter via the subclavian vein. To reduce the high mortality of this rare complication, quickly applicable diagnostic measures and adequate therapy of pericardiocentesis are indicated. Prompt recognition and treatment of pericardial tamponade are imperative if a disastrous outcome is to be prevented
Expandable vertebral body replacement in patients with thoracolumbar spine tumors
No full textIntroduction: The objectives of surgical interventions for tumoral lesions of the spine include the establishment and improvement of tumor-related symptoms. Anterior tumor resection followed by reconstruction indicated if surgical treatment allowed a marginal removal of the tumor or could extend the individual survival rate in combination with adjuvant therapy options. Sufficient re-stabilization depends on adequate anterior column reconstruction. The purpose of this retrospective study was to present our experiences and results after anterior tumor resection followed by reconstruction with the expandable vertebral body replacement device (VBR, Ulrich, Germany) based on clinical application over 4 degrees years. Patients and methods: We carried out an anterior tumor resection followed by reconstruction using an anterior extendable device in 32 patients with different spine tumors between 1996 and 2000. A retrospective evaluation was executed considering the patients medical records and radiological findings. Additionally, a clinical and radiological investigation of still living postoperative patients was carried out. Results: The mean surgical time of all evaluated patients was 317.2 min. The average blood loss was 1,272.5 ml. According to the Tokuhashi score, patients with a postoperative survival time of at least 12 months demonstrated a score value >= 9 points. According to our evaluated patients group metastatic lesions of the spine represented the largest group (78.1%). The average survival rate of this group amounted to 18.4 months postoperatively. Considering primary tumors the average survival rate at the time of last re-examination amounted to 34.8 months postoperatively. Preoperative neurological pathologies were present in 12 patients (Frankel stage C-D). During the postoperative monitoring period 58.3% of the patients demonstrated an improvement in initial neurological findings. There were no intraoperative complications or perioperative deaths. Implant dislocations were not observed. Conclusion: On account of the underlying, the anterior tumor resection with supplementary instrumentation represented a sufficient procedure in spinal tumor surgery. Adjuvant therapy can influence the postoperative survival period positively in addition to the surgical procedure. Following anterior tumor resection, extendable vertebral body replacements like the VBR device provide immediate spine stability by excellent defect adaptation. With regard to their intraoperative flexibility, expandable cages are more advantageous in contrast to non-expandable implants or bone grafts
Autologous osteochondral grafts in the treatment of cartilage defects of the knee joint
No full textAutologous osteochondral grafting (mosaicplasty) was performed on 18 patients with grade IV cartilage defects of the knee joint. The average age of these 12 men and 6 women was 36 years, follow-up time was 27.2 months and defect size was 252 mm(2) (18x14mm). After plain anteroposterior and lateral radiographs and MRI (STIR sequence) examination, diagnostic arthroscopy was performed, followed by autologous osteochondral grafting, avoidance of weight bearing for 6-8 weeks, physiotherapy and continuous passive motion. All patients showed, radiologically (MRI), a full coverage of the defect with articular surface congruity postoperatively. The postoperative ICRS score was normal for 12 and nearly normal for 6 patients. Seven patients showed early persistent joint effusion for an average of 5.3 months. Hyaline-like cartilage coverage was found in four patients on second-look arthroscopy. The transplantation of autologous osteochondral grafts is being applied in an effort to reconstruct the affected articular surface with properties similar to those of hyaline cartilage. This method retains the integrity and function of a damaged joint, providing promising results in terms of preventing the development of early arthritis in young patients
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
Circumferential fusion of the lumbar and lumbosacral spine using a carbon fiber ALIF cage implant versus autogenous bone graft: A comparative study
No full textThis study reports on 92 patients treated with circumferential lumbar fusions for degenerative conditions. The elected procedure was a circumferential fusion using transpedicular stabilization. Two groups were examined depending on whether they were stabilized anteriorly with autogenous bicortical iliac crest graft (n = 38) or with an ALIF carbon fiber cage implant (n = 54). The patients were evaluated for clinical and radiographic outcome. The minimum follow-up interval was at least 12 months. Fusion rates, postoperative loss of correction, and clinical results, including pain at the bone donor site, neurologic function, satisfaction, depression, and consumption of analgesics, were not significantly different between patients with autogenous bone graft and patients with carbon cage. This study failed to prove major advantages of the carbon cages in the clinical and radiologic outcome
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
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
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