1,720,974 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
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
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
Magnetic Particle Imaging Angiography in human sized organs by employing a multimodal ex vivo pig kidney perfusion system
No full textEinleitung: Das MPI ist eine strahlenfreie Bildgebungsmethode, die aufgrund hoher zeitlicher Auflösung und dreidimensionaler Abbildung des Untersuchungsvolumens als vielversprechend für Angiographien und endovaskuläre Interventionen gilt. Bisher wurden jedoch noch keine Gefäße innerhalb eines Organs mittels MPI dargestellt. Dies liegt daran, dass die Ortsauflösung der vorhandenen, für Angiographien geeigneten, präklinischen MPIScanner für Kleintierorgangefäße zu gering ist und die Scanner zu klein für Tiere größeren Maßstabes oder Menschen sind.
Zielsetzung: Ziel der vorliegenden Arbeit war es, ein multimodales, für die DSA, für die MRT und für das MPI kompatibles Perfusionssystem zur ex vivo Perfusion von Schweinenieren zu entwickeln, um mit den vorhandenen MPI-Scannern Angiographien innerhalb eines Organs menschlicher Größe durchzuführen. Die MPI-Angiographien sollte mit der MRA als etablierter ebenfalls dreidimensionaler angiographischer Bildgebungstechnik verglichen werden.
Material und Methoden: Es wurde ein für alle Techniken kompatibles ex vivo Perfusionssystem für Schweinenieren entwickelt und anhand von zehn Nieren evaluiert.
Neun weitere Nieren wurden mittels der beiden dreidimensionalen Bildgebungsmodalitäten MRA und MPI abgebildet. Zwei dieser Nieren wurden zusätzlich auch in der DSA dargestellt, um exemplarisch den Erhalt des Gefäßsystems unter der ex vivo Perfusion zu prüfen. Im MPI wurden zwei unterschiedliche Tracer evaluiert. Die Anzahl an sichtbaren Organgefäßen in der MR- im Vergleich zur MPI-Angiographie wurde von zwei Beobachtern bestimmt. Die zum MPI-Signal potenziell quantitative Eisenkonzentration der MPI-Tracer innerhalb des Verlaufs eines Organgefäßes wurde kalkuliert.
Ergebnisse: Das entwickelte Modell erlaubte die stabile ex vivo Perfusion von Schweinenieren für bis zu drei Stunden. Mittels DSA konnte demonstriert werden, dass sich das Gefäßsystem unter der ex vivo Perfusion weitestgehend erhalten zeigte. Neben der DSA und der MRA gelang erstmals auch im MPI die Abbildung einzelner Organgefäße. Dabei bildete das MPI in etwa ein Drittel der in der MRA sichtbaren Gefäße ab. Es zeigte sich keine relevante Differenz in der Gefäßdarstellung zwischen beiden evaluierten MPI-Tracern. Die Quantifizierung der Eisendistribution im Organ sowie die Darstellung eines akzidentellen Gefäßverschlusses im MPI war prinzipiell möglich.
Schlussfolgerung: Das vorgestellte ex vivo Organperfusionssystem erlaubt die Untersuchung von Schweinenieren als Beispiel für Organe humaner Größe im MPI trotz bestehender Restriktionen der für Angiographien geeigneten, verfügbaren MPI-Scanner.
Dadurch kann das Potential des MPI für humane Angiographien evaluiert werden.
Konkret sind unter anderem die Evaluation von MPI-Tracern, die prinzipielle Eisenquantifizierung der injizierten Tracer und die Darstellung von Gefäßverschlüssen innerhalb eines Organs im MPI möglich.Introduction: MPI is a promising radiation-free imaging technique for angiography and endovascular interventions due to its ability to produce three-dimensional, high temporal resolution images. At this time, however, MPI is not being used to image the vasculature of specific organs. This is due to the fact that the only MPI scanners currently available are employed in the pre-clinical setting, in conjunction with small-animal models; the spatial resolution of such scanners is not yet sufficient for larger animal or human models.
Purpose: To develop an ex vivo perfusion system compatible to the available MPI scanners, DSA, and MRA on a porcine kidney model, as an organ system similar in size to its human counterpart, and to compare the results of the MPI to MRA, as established three-dimensional angiographic imaging technique.
Material and Method: A DSA, MRA and MPI compatible ex vivo perfusion system was developed for porcine kidneys and evaluated in ten kidneys. Following preliminary evaluation of the perfusion system, nine further kidneys were imaged with both MRA and MPI as threedimensional imaging methods. Two of these were also imaged with DSA, as high spatial resolution imaging method, to verify the presence of intact renal capillary systems during ex vivo perfusion. For MPI, two different tracers were evaluated. The number of visible organ vessels in MRA and MPI were determined by two observers and the two techniques were compared. As the MPI signal is potentially able to quantify the iron concentration of the injected MPI tracers, the iron concentration within an organ vessel was calculated. Results: The developed perfusion system allowed for the stable ex vivo perfusion of porcine kidneys for up to three hours. The overall intact capillary structure of the ex vivo-perfused kidneys was demonstrated by DSA. Imaging of organ vessels was not only feasible with DSA and MRA, but also with MPI. The comparison of both three-dimensional imaging techniques found that MPI was able to capture approximately one third of the organ vessels visualized by MRA. There was no relevant difference between the MPI tracers with regards to the number of displayed vessels. Quantification of iron distribution was also feasible. Furthermore, vascular occlusion, accidentally occurring in one organ, could depicted by MPI.
Conclusion: An ex vivo organ perfusion system is presented that allows for the examination of porcine kidney vessel perfusion with the use of the currently available small-animal MPI scanners. Due to their similarity in size to human kidneys, the potential for MPI-based angiography in patients can thus be evaluated. This includes in particular the evaluation of MPI tracers, the quantification of organ iron concentration, as well as the imaging of vascularocclusions
Work expectations, their fulfillment, and exhaustion among radiologists of all career levels: what can be learned from the example of Germany
No full textAbstract Objectives To evaluate work expectations of radiologists at different career levels, their fulfillment, prevalence of exhaustion, and exhaustion-associated factors. Methods A standardized digital questionnaire was distributed internationally to radiologists of all career levels in the hospital and in ambulatory care via radiological societies and sent manually to 4500 radiologists of the largest German hospitals between December 2020 and April 2021. Statistics were based on age- and gender-adjusted regression analyses of respondents working in Germany (510 out of 594 total respondents). Results The most frequent expectations were “joy at work” (97%) and a “good working atmosphere” (97%), which were considered fulfilled by at least 78%. The expectation of a “structured residency within the regular time interval” (79%) was more frequently judged fulfilled by senior physicians (83%, odds ratio (OR) 4.31 [95% confidence interval (95% CI) 1.95–9.52]), chief physicians (85%, 6.81 [95% CI 1.91–24.29]), and radiologists outside the hospital (88%, 7.59 [95% CI 2.40–24.03]) than by residents (68%). Exhaustion was most common among residents (physical exhaustion: 38%; emotional exhaustion: 36%), in-hospital specialists (29%; 38%), and senior physicians (30%; 29%). In contrast to paid extra hours, unpaid extra hours were associated with physical exhaustion (5–10 extra hours: OR 2.54 [95% CI 1.54–4.19]). Fewer opportunities to shape the work environment were related to a higher probability of physical (2.03 [95% CI 1.32–3.13]) and emotional (2.15 [95% CI 1.39–3.33]) exhaustion. Conclusions While most radiologists enjoy their work, residents wish for more training structure. Ensuring payment of extra hours and employee empowerment may help preventing burnout in high-risk groups. Key Points • Most important work expectations of radiologists who work in Germany are “joy at work,” a “good working atmosphere,” “support for further qualification,” and a “structured residency within the regular time interval,” with the latter containing potential for improvement according to residents. • Physical and emotional exhaustion are common at all career levels except for chief physicians and for radiologists who work outside the hospital in ambulatory care. • Exhaustion as a major burnout criterion is associated with unpaid extra hours and reduced opportunities to shape the work environment
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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