1,720,992 research outputs found
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
Graph-matching and FEM-based registration of computed tomographies for outcome validation of liver interventions
No full textLiver cancer is one of the leading causes of death worldwide. One of the reasons for that is the high tumor recurrence rate. The only way to reduce the recurrence rate is to ensure that all carcinogenic cells are destroyed after intervention. Unfortunately, the information available to assess the outcome of an intervention is limited. In the clinical routine, a pair of pre- and post-operatively gathered computed tomographies (CT) of the abdomen are typically compared to decide whether the patient needs further treatment. However, the post-operative liver will be deformed due to breathing and intervention which will complicate the comparison task by simple inspection of both images. The results presented in this thesis will support the physician during the outcome validation process after minimally invasive interventions and open liver surgeries. Therefore, the physician is provided with qualitative measures and visualizations that support him in the decision making task. The basis of a reliable outcome validation is an accurate non-rigid registration method. This thesis proposes to combine internal correspondences at vessel ramifications and landmarks at the surface of the organ to increase the accuracy of the registration results. The internal correspondences are the result of a novel efficient and fully automatic graph matching method. Landmarks at the surface of the liver are given by a method that detects the organs that are adjacent to it at each surface point. Both types of landmarks are incorporated in a FEM-based registration. The registration method has been tested in 25 pairs of pre- and post-operative clinical CT images achieving an average accuracy of 1.22 mm and a positive predictive value of 0.95. In consequence of the accuracy obtained with the proposed methods the physician is able to determine with certainty if the outcome of the intervention was satisfactory. Hence, he can without delay decide to re-treat the patient if needed to remove the remnant tumor. This fast response could at the end reduce the tumor recurrence rate.Leberkrebs ist eine der größten Todesursachen weltweit. Einer der Gründe dafür ist die hohe Rekurrenz. Um diese zu reduzieren, muss sichergestellt werden, dass alle karzinogenen Zellen nach dem Eingriff zerstört werden. Leider sind die verfügbaren Informationen, um das Resultat eines Eingriffes zu bewerten, begrenzt. Die Entscheidung, ob ein Patient weiter behandelt werden muss, basiert auf dem Vergleich von präoperativen und postoperativen Computertomographien (CT) des Abdomens. Allerdings wird die postoperative Leber aufgrund des Eingriffes und der Atmung stark deformiert, wodurch der visuelle Vergleich erschwert wird. Die Ergebnisse dieser Arbeit unterstützen den Arzt bei der Bewertung minimalinvasiver und offener Lebereingriffe. Dafür werden dem Arzt quantitative Maße und Visualisierungen zur Verfügung gestellt. Eine genaue deformierbare Registrierung bildet die Grundlage für eine zuverlässige Bewertung. Die in dieser Dissertation vorgeschlagene Methode verwendet anatomische Landmarken basierend auf den Gefäßen der Oberfläche der Leber, um eine hohe Genauigkeit zu erreichen. Landmarken innerhalb der Leber werden anhand einer neuartigen, effizienten und voll automatischen Graph-Matching Methode gefunden. Oberflächliche Landmarken werden anhand einer neuen Methode detektiert, die die Leberoberfläche anhand von benachbarten Organen einteilt. Beide Arten von Landmarken wurden in einer FEM basierten Registrierungsmethode integriert. Für die Evaluierung wurden 25 CT Bildpaare bestehend aus jeweils einem prä- und einem postoperativen Datensatz verwendet. Die vorgestellte Methode erreicht eine mittlere Genauigkeit von 1.22 mm und einen positiven Vorhersagewert (PPV) von 0.95. Aufgrund der hohen Genauigkeit der vorgestellten Methode kann der Arzt über den Erfolg des Eingriffes mit einem hohen Maß an Sicherheit entscheiden und den Patienten unverzüglich weiterbehandeln, falls der Tumor nicht vollständig beseitigt wurde. Dadurch kann letztendlich ein Wiederauftreten des Tumors vermieden oder reduziert werden
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Cone-beam computed tomography-guided stereotactic liver punctures: a phantom study
Get PDFPURPOSE
Images from computed tomography (CT), combined with navigation systems, improve the outcomes of local thermal therapies that are dependent on accurate probe placement. Although the usage of CT is desired, its availability for time-consuming radiological interventions is limited. Alternatively, three-dimensional images from C-arm cone-beam CT (CBCT) can be used. The goal of this study was to evaluate the accuracy of navigated CBCT-guided needle punctures, controlled with CT scans.
METHODS
Five series of five navigated punctures were performed on a nonrigid phantom using a liver specific navigation system and CBCT volumetric dataset for planning and navigation. To mimic targets, five titanium screws were fixed to the phantom. Target positioning accuracy (TPECBCT) was computed from control CT scans and divided into lateral and longitudinal components. Additionally, CBCT-CT guidance accuracy was deducted by performing CBCT-to-CT image coregistration and measuring TPECBCT-CT from fused datasets. Image coregistration was evaluated using fiducial registration error (FRECBCT-CT) and target registration error (TRECBCT-CT).
RESULTS
Positioning accuracies in lateral directions pertaining to CBCT (TPECBCT = 2.1 ± 1.0 mm) were found to be better to those achieved from previous study using CT (TPECT = 2.3 ± 1.3 mm). Image coregistration error was 0.3 ± 0.1 mm, resulting in an average TRE of 2.1 ± 0.7 mm (N = 5 targets) and average Euclidean TPECBCT-CT of 3.1 ± 1.3 mm.
CONCLUSIONS
Stereotactic needle punctures might be planned and performed on volumetric CBCT images and controlled with multidetector CT with positioning accuracy higher or similar to those performed using CT scanners
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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