1,721,157 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
Technische Fehler bei der Platzierung von Pedikelschrauben in der minimalinvasiven computerunterstützten Wirbelsäulenchirurgie
No full textBackground: The placement of pedicle screws (PS) has become a cornerstone in spinalsurgery and computer assisted navigation (CAN) reduces PS misplacements. Most previousattempts on evaluating the technical accuracy by measuring deviations from the virtual and thereal PS screws have been based on a preoperative computer tomography (CT) scan, both influoroscopy guided and in robotic navigation guided. As such, these studies did not address thefundamental question of the technical accuracy of the navigation device itself afterintraoperative placement of the virtual PS or of intraoperative risk factors. Other studies thatassessed the technical accuracy from intraoperative placed virtual screws were instead limitedin size, generalizability, and without an analysis of possible risk factors. Therefore, we aim toinvestigate the technical errors of intraoperative CAN in the placement of PS in MISS andexplore the associated risk factors for PS mispositioning. Methods: In this retrospective study,175 patients ≥18 years old (operated 2015-2021) with PS fixation were included. Intraoperative3D scans were fused with the first postoperative CT scan. Primary endpoint was measured asangular deviation (PAD) in degrees and lateral deviation (APD) in mm between the plannedand actual PS position and was defined as the technical errors. Established deviation criteria(according to Gertzbein) were correlated. Age, gender, body mass index (BMI), back tissuedepth (BTD), PS loosening, surgical time (ST), estimated blood loss (EBL), PS size and typeof navigation device were considered as possible outcome affecting variables. Statisticalanalyses were performed using Mann-Whitney and Kruskal-Wallis tests. A multivariategeneralized linear model (GLM) analyzed the impact on the primary endpoint. Results: 952PS were measured. The mean PAD was 5.32±3.70° and the mean APD was 2.97±1.83 mm. Alarger PAD was associated with the use of the Spine Tracker compared to SpineMask®. MoreEBL and higher BMI were associated with greater APD. A larger PAD and APD wereassociated with longer ST. Higher PAD and APD were associated with PS loosening. PS lengthand male patients predicted better PAD, Spine Tracker predicted worse PAD, and longer STpredicted worse PAD and APD. Conclusion: The technical error was 5.32° (PAD) and 2.97mm (APD). PS dimensions, ST, EBL, BMI, navigation type, and gender category wereassociated with more PS deviations. Nevertheless, both clamp and adhesive fixed referenceframes can be considered clinically accurate, but surgeons should be mindful of possible riskfactors for technical inaccuracies. We encourage further studies to assess possible outcomeaffecting variables on PS placements
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
Retrospektive Evaluation von radiologischen und klinischen Parametern nach Wirbelkörperersatz mit distrahierbaren Titan Cages
No full textBei hochgradigen Wirbelsäulenveränderungen, die mit ausgeprägter Fehlstellung und Einengung des Myelons oder gar mit neurologischen Ausfällen einhergehen, ist eine Wirbelkörperersatz-Operation heutzutage Standard. In der Neurochirurgie der Uniklinik Freiburg werden hierzu seit 2005 expandierbare Titancages verwendet. Die vorliegende Arbeit untersucht, ob bei den 2005-2018 in der Neurochirurgie der Uniklinik Freiburg durchgeführten Wirbelkörperersatz-OPs die Ergebnisse über den 1-Jahres-Zeitraum der Nachuntersuchungen hinsichtlich Fusionsstatus, Sinterung und klinischem Outcome mit den für andere Wirbelkörperersatzverfahren in der Literatur publizierten Ergebnissen vergleichbar sind. Für die Arbeit wurden alle Patienten mit expandierbaren Titancages „ADDplus“ der Firma Ulrich medical aus den Jahren 2005-2018, bei denen eine 1-Jahres-Kontrolluntersuchung vorlag, ausgewertet. Hierzu wurden die prä- und postoperativen radiologischen Unter-suchungen sowie die dazugehörigen Arztbriefe über die stationären Behandlungen und ambulanten Kontrollen zur Beurteilung des klinischen Verlaufs herangezogen. Es wurden die Segmenthöhen und die Lordosewinkel im Verlauf sowie der Fusionsstatus nach einem Jahr von zwei unterschiedlichen Ratern erfasst. Die klinischen Angaben aus den Arztbriefen wurden gemäß der Odom-Skala eingeteilt. Zum Vergleich wurde Literatur seit den Anfängen des Wirbelkörperersatzes ausgewertet. Die alternativen Methoden umfassten autologe Transplantate, allogene Knochentransplantate, Acrylpolymere und nicht-distrahierbare Cages aus Titan oder PEEK. Als neueste Entwicklung sind individualisierte Implantate aus dem 3D-Drucker in der Erprobung, wobei als Materialien sowohl metallische als auch nichtmetallische Substrate zum Einsatz kommen können. Das Vorgehen ist (noch) kein Standardverfahren. Zusammenfassend lässt sich feststellen, dass in der vorliegenden Studie die Fusionsrate bei für die distrahierbaren Titancages mit 66% vergleichbar bis überdurchschnittlich hoch ausfiel und in der Beurteilung der klinischen Ergebnisse der 1-Jahres-Kontrolle 85% als „gut“ oder „exzellent“ eingestuft wurden
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
Querschnitt und neurologische Symptomatik bei Wirbelmetastasen - Genese und Ableitung von Handlungsempfehlungen
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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