1,720,955 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
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
Dynamic 18F-FET PET/CT to differentiate recurrent primary brain tumor and brain metastases from radiation necrosis after single-session robotic radiosurgery
Get PDFCyberknife robotic radiosurgery (RRS) provides single-session high-dose radiotherapy of brain tumors with a steep dose gradient and precise real-time image-guided motion correction. Although RRS appears to cause more radiation necrosis (RN), the radiometabolic changes after RRS have not been fully clarified. 18F-FET-PET/CT is used to differentiate recurrent tumor (RT) from RN after radiosurgery when MRI findings are indecisive. We explored the usefulness of dynamic parameters derived from 18F-FET PET in differentiating RT from RN after Cyberknife treatment in a single-center study population
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
Differenzierung zwischen Tumorrezidiv und Radionekrose mittels 18F-FET-PET/CT nach radiochirurgischer Behandlung von Hirntumoren mit dem CyberKnife
Get PDFBACKGROUND: 18F-FET-positron emission tomography/computed tomography (FET-PET) has reliable diagnostic accuracy in differentiating recurrent brain tumor from radionecrosis after radiosurgery. This explorative study analyzed this role of FET-PET in brain tumors treated by image-guided robotic stereotactic radiosurgery using CyberKnife® (CK-RS).
METHOD: The study population were patients who underwent FET-PET to resolve inconclusive magnetic resonance imaging (MRI) findings in the clinical follow-up of primary and secondary brain lesions after CK-RS in 2011-2017. Histology reports or best supporting clinicoradiological evidence served as reference standard. Static (tumor-to-background ratio [TBR]) and dynamic (time to peak [TTP] and time-activity curve [TAC] pattern) parameters were determined. Three TAC patterns were distinguished: continuously ascending curve (I), ascending curve followed by plateau (II), and steep ascent followed by slow descent (III). Receiver operating characteristic curve analysis and diagnostic accuracy tests were performed. Analyses were performed for all lesions (TOTAL) and brain metastases only (METS). MRI lesions not detected by FET-PET were qualitatively analyzed.
RESULTS: Fourteen patients (median 52 years, range 16-79 years) with a total of 28 lesions (5 primary brain tumor lesions in 2 patients and 23 metastases in 12 patients) were included. The median time interval between CK-RS and FET-PET was 10 months (range 4-35). Histology was available for 7/28 lesions (25%), all correctly diagnosed by FET-PET. TBRs were higher in recurrent tumor than radionecrosis (median TBRmax of 5.5 vs. 3.8 in TOTAL and 5.0 vs. 3.5 in METS; median TBRmean of 2.6 vs. 2.1 in TOTAL and 2.4 vs. 2.0 in METS). Mean TTP was shorter in tumors (9.6 vs. 16.7 min in TOTAL and 8.3 vs. 13.7 min in METS) while median TTP did not differ. No significant cut-offs for TBR and TTP were found, thus published cut-offs of 1.95 for TBRmean and 20 min for TTP were used. The best diagnostic accuracy was achieved for combined TBRmean and TAC: TOTAL (METS): 75% (75%) sensitivity, 63% (71%) specificity, and 71% (74%) accuracy. When only TAC patterns were used, accuracy was 82% in TOTAL and 87% in METS. Post-test diagnostic probability was 12% (TOTAL) and 16% (METS) higher than that of follow-up MRI. Three lesions without PET tracer uptake were stable over time.
CONCLUSION: This explorative study shows that the best diagnostic accuracy of FET-PET in differentiating brain tumor recurrence from radionecrosis after CK-RS is achieved when combined static and dynamic parameters are used, resulting in up to 16% higher diagnostic probability than standard follow-up MRI.HINTERGRUND: Die 18F-FET-Positron-Emissions-Tomographie/Computertomographie (FET-PET) weist eine verlässliche diagnostische Genauigkeit in der Differenzierung von Hirntumorrezidiven und Radionekrosen nach radiochirurgischer Behandlung auf. In dieser explorativen Studie wurde diese Rolle der FET-PET bei Hirntumoren nach bildgesteuerter robotergestützter stereotaktischer Radiochirurgiebehandlung mittels CyberKnife® (CK-RS) analysiert.
METHODIK: Eingeschlossen wurden Patienten, die sich von 2011 bis 2017 einer FET-PET-Untersuchung zur Abklärung unklarer magnetresonanztomographischer (MRT) Befunde im Rahmen der klinischen Nachsorge von primären und sekundären Hirnläsionen nach CK-RS unterzogen. Als Referenzstandard dienten Histologiebefunde oder klinisch-radiologische Befunde als Best Supporting Evidence. Statische (Tumor-to-Background Ratio [TBR]) und dynamische (Time to Peak [TTP] und Time-Activity Curve [TAC]) Parameter wurden ermittelt. Es wurden drei TAC-Muster unterschieden: kontinuierlich ansteigende Kurve (I), ansteigende Kurve mit nachfolgendem Plateau (II), und steil ansteigende Kurve mit flachem Abfall (III). Grenzwertoptimierungskurven wurden berechnet und diagnostische Genauigkeitstests durchgeführt. Analysen erfolgten für sämtliche Läsionen (TOTAL) sowie Hirnmetastasen (METS). Im MRT detektierte Läsionen, die nicht in der FET-PET abgrenzbar waren, wurden qualitativ analysiert.
ERGEBNISSE: Vierzehn Patienten (Medianalter 52 Jahre, Spannweite 16-79 Jahre) mit insgesamt 28 Hirnläsionen (5 primären Hirntumorläsionen in 2 Patienten und 23 Hirnmetastasen in 12 Patienten) wurden eingeschlossen. Die Medianzeit zwischen CK-RS und der FET-PET betrug 10 Monate (Spannweite 4–35 Monate). Ein histopathologischer Befund lag bei 7 von 28 Läsionen (25%) vor, die sämtlich mit der FET-PET korrekt diagnostiziert wurden. Die TBR war bei Hirntumorrezidiven höher als bei Radionekrosen (Median TBRmax TOTAL 5,5 vs. 3,8; METS 5,0 vs. 3,5; Median TBRmean TOTAL 2,6 vs. 2,1; METS 2,4 vs. 2,0). TTP war im Mittel bei Hirntumoren kürzer (TOTAL 9,6 vs. 16,7 min; METS 8,3 vs. 13,7); die mediane TTP unterschied sich jedoch nicht. Signifikante TBR- und TTP-Grenzwerte ließen sich nicht berechnen, daher kamen eine in früheren Studien etablierte TBRmean von 1,95 sowie eine TTP von 20 min zur Anwendung. Die besten diagnostichen Genauigkeitswerte fanden sich für die Kombination von TBRmean und TAC: TOTAL (METS): 75% (75%) Sensitivität, 63% (71%) Spezifizität und 71% (74%) Genauigkeit. Bei der alleinigen Betrachtung der TAC-Muster war die Genauigkeit 82% (TOTAL) bzw. 87% (METS). Die Nachtestdiagnosewahrscheinlichkeit war 12% (TOTAL) bzw. 16% (METS) höher als die der vorangehenden MRT-Untersuchung. Drei in der FET-PET nicht nuklidavide Läsionen waren im Verlauf stabil.
SCHLUSSFOLGERUNG: Die beste diagnostische Genauigkeit der FET-PET in der Unterscheidung von Hirntumorrezidiven und Radionekrosen nach CK-RS ergibt sich in der vorgestellten explorativen Studie für die Kombination von statischen und dynamischen Parametern. Hierdurch wird eine bis zu 16% höhere Diagnosewahrscheinlichkeit im Vergleich zur herkömmlichen Nachsorge-MRT erzielt
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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