1,721,059 research outputs found
Neurosurgery in the storm of COVID-19: Suggestions from the Lombardy region, Italy (ex malo bonum)
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Indocyanine Green and Contrast-Enhanced Ultrasound Videoangiography: A Synergistic Approach for Real-Time Verification of Distal Revascularization and Aneurysm Occlusion in a Complex Distal Middle Cerebral Artery Aneurysm
No full textBackground: Distal outflow occlusion and extracranial-intracranial bypass represent a possible option for the surgical management of complex middle cerebral artery (MCA) aneurysm. A limitation of the distal clipping strategy combined to bypass is related to the difficulties in predicting intraoperatively the good blood flow supply to the brain territory distal to the aneurysm and the extent and speed of aneurysmal thrombosis. Methods: We present an innovative approach in which contrast-enhanced ultrasound (CEUS) and indocyanine green videoangiography (ICG-VA) have been synergistically used to study the effect of distal clipping on the aneurysm flow and the parenchymal blood flow after the bypass. We used this approach in a patient harboring a fusiform, partially thrombosed distal left MCA aneurysm. Results: The patient was treated by a superficial temporal artery–MCA bypass, followed by MCA clipping immediately distally to the aneurysm. ICG-VA was used to evaluate bypass patency and brain perfusion in the area supplied by the bypass. CEUS was used to confirm the characteristics of the aneurysm and to explore the proximal MCA compartment immediately after dural opening, and to verify in real time the effect on aneurysm flow determined by distal outflow occlusion. Postoperative imaging confirmed aneurysm occlusion and patency of the bypass. The patient did not experience any neurologic sequelae. Conclusions: We present the first report of a synergistic intraoperative utilization of ICG-VA and CEUS in studying parenchymal perfusion and aneurysm flow in complex neurovascular procedures
Motor evoked potentials and bispectral index-guided anaesthesia in image-guided mini-invasive neurosurgery of supratentorial tumors nearby the cortico-spinal tract
No full textAIM: To describe and evaluate the anaesthesiological regimen used in neurophysiologically monitored image-guided mini-invasive neurosurgery. MATERIAL and METHODS: Twenty-four patients underwent elective surgery under general anaesthesia that was administered through Target Controlled Infusion (TCI) for effect-site concentration (Ce) of Propofol and Remifentanil, targeting the Bispectral Index (BIS) in the 40-60 intervals. The stimulating intensity of transcranial motor evoked potentials (tMEP), BIS, Propofol and Remifentanil Ce were collected at MEPs threshold (T) definition (respectively BIS@T, CeProp@T and CeRemi@T). Intraoperative seizure, explicit recall for intraoperative awareness and clinical motor status were assessed. RESULTS: CeProp@T and CeRemi@T ranged respectively between 1.5-2.2 μg/ml (Median 1.6 μg/ml) and 3.5-18 ng/ml (Median 8 ng/ml) that were effective in keeping the BIS@T between 40 and 60 in all surgeries. tMEP thresholds ranged between 45 and 120 mA. There was no correlation between CeProp@T, CeRemi@T and tMEP, as well as between BIS@T and respectively tMEP, CeProp@T, CeRemi@T. None of patients had induced electrical seizure or explicit recalls. Motor scores were equal to preoperative values in 22/24 patients. CONCLUSION: BIS-guided general anaesthesia within a 40-60 interval, with low Ce of Propofol (<2 μ/ml) and high analgesic regime allow reliable tMEP measurements, avoiding postoperative neurological impairment and major adverse outcomes, such as seizure and awareness
Prospective identification of a CD133-negative, putative cancer stem cell population in adult human glioblastomas
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