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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
MRI- based versus CT- based thrombolysis in acute ischemic stroke
No full textDie intravenöse Lysetherapie mit rt-PA ist die einzige zugelassene kausale
Therapie beim akuten ischämischen Schlaganfall. Vor Indikationsstellung ist
eine zerebrale Bildgebung zwingend erforderlich: meistens erfolgt der
Ausschluss einer intrazerebralen Blutung als Ursache der Symptomatik mittels
Computertomographie (CT). Die MRT hingegen erlaubt nicht nur den
Blutungsausschluss, sondern auch die Darstellung der Lokalisation und Größe
des ischämischen Hirnareals innerhalb des therapeutischen Zeitfensters von 4,5
Stunden. Ob diese zusätzlichen Informationen, die die MRT liefert, einen
Einfluss auf die Sicherheit und Effektivität der Lysetherapie haben, ist
derzeit Gegenstand der wissenschaftlichen Diskussion. Für diese Arbeit wurden
die Daten aus einem prospektiv geführten, monozentrischen Kohortenregister
verwendet, in welches alle Patienten mit einem akuten ischämischen
Schlaganfall aufgenommen wurden, die am Campus Benjamin Franklin innerhalb von
4,5 Stunden eine Lysetherapie erhalten hatten. Alle Patienten erhielten
entweder eine CT- oder eine MRT-Untersuchung vor Beginn der Lysetherapie. Als
Parameter für die Sicherheit der Therapie wurde die Rate an symptomatischen
intrakraniellen Blutungen (SICH) , die Rate an Hirnödemen und die Mortalität
an Tag 7 analysiert. Endpunkte nach 3 Monaten waren die Mortalität und die
Unabhängigkeit der Patienten, definiert als modified Rankin Score (mRS) von 0
bis 2 Punkten. Insgesamt wurden 345 Patienten in die Analysen eingeschlossen.
Von diesen erhielten 141 eine MRT- und 204 eine CT- Untersuchung vor
Lysetherapie. Hinsichtlich der erhobenen Basisdaten (Alter, Schweregrad des
Schlaganfalls, Glukosespiegel, Blutdruck etc.) zeigten sich keine statistisch
signifikanten Unterschiede zwischen den beiden Bildgebungsgruppen. In der CT-
Gruppe zeigte sich jedoch eine signifikant höhere Rate an kardialen
Vorerkrankungen (KHK, Herzinsuffizienz). In der MRT-Gruppe beobachteten wir
eine signifikant geringere Mortalität an Tag 7 (1% versus 10%, p=0.001), eine
signifikant geringere Rate an SICH (1% versus 6%, p=0.010) und einen nicht
signifikanten Unterschied bezüglich der Entwicklung eines Hirnödems (2% versus
6%, n.s.). In den multivariaten Analysen war die Mortalität an Tag 7
unabhängig mit der MRT-basierten Lysetherapie assoziiert. Diese Assoziation
blieb auch dann erhalten, wenn die kardialen Vorerkrankungen in die Analysen
mit einbezogen wurden. Für die Mortalität nach 3 Monaten zeigte sich ein nicht
signifikanter Unterschied zu Gunsten der MRT-Gruppe (16% versus 23%, n.s.). In
den multivariaten Analysen war die Mortalität nach 3 Monaten unabhängig mit
Alter, Schlaganfallschweregrad, Hirnödem, SICH, Pneumonie und KHK assoziiert.
Weder für Mortalität noch für Unabhängigkeit nach 3 Monaten war die initiale
Bildgebungsmethode ein unabhängiger Prädiktor. Schlussfolgernd lässt sich
sagen, dass die Anwendung der MRT zur Indikationsstellung für eine
Lysetherapie mit einer signifikant niedrigeren Frühmortalität assoziiert ist.
Diese Reduktion der Frühmortalität ist zum einen in einer Reduktion der Rate
an SICH begründet und zum anderen durch eine Reduktion von Lysetherapien bei
Patienten, die aufgrund ihres großen Schlaganfalles ein Hirnödem entwickeln.
Insgesamt jedoch erscheint der Einfluss der Bildgebungsmethode auf die frühe
Phase nach der Lysetherapie beschränkt zu sein: im Outcome nach 3 Monaten
zeigte sich in den hier vorliegenden Daten kein statistisch signifikanter
Unterschied zwischen der MRT- und der CT-Kohorte. Desweiteren lässt sich aus
den hier vorliegenden Ergebnissen schlussfolgern, dass Patienten mit kardialen
Vorerkrankungen mit höherer Wahrscheinlichkeit eine CT-Untersuchung erhalten
und somit in Kohortenstudien die MRT-Gruppe kardial gesünder ist.In acute ischemic stroke brain imaging is mandatory in the decision whether to
perform intravenous thrombolysis with rt-PA. The most widespread used imaging
modality to exclude intracranial hemorrhage is plain computed tomography (CT).
However there is an ongoing debate whether the information provided by
magnetic resonance imaging (MRI) could improve the selection of patients for
thrombolysis. We investigated whether the choice of imaging modality (MRI vs.
CT) affects therapy safety and the patients’ outcome. Analyses are based on
data from a prospective, single-center observational study that included all
patients with acute ischemic stroke who received intravenous thrombolysis
within 4.5 hours. Stroke severity was assessed by National Institutes of
Health Stroke Scale. Safety was assessed by rates of symptomatic intracranial
hemorrhage (SICH), brain edema with mass effect and 7-day-mortality. Outcome
was assessed at 3 months as mortality and proportion of independent patients
(modified Rankin Score (mRS) between 0 and 2). We analyzed 345 patients of
whom 141 received multimodal MRI and 204 received plain CT prior to treatment.
Groups did not differ significantly in terms of age, neurological deficit,
rate of elevated glucose level or rate of very high blood pressure. However
patients with CT-based thrombolysis had significantly higher rates of cardiac
comorbidities (coronary artery disease, heart failure). In the MRI-group, we
observed a lower rate of 7-day-mortality (1% versus 10%; p=0.001), a lower
rate of SICH (1%versus 6%; p=0.010) and a non-significant lower rate of brain
edema with mass effect (2% versus 6%; n.s.). In multivariable analysis, 7-day-
mortality was independently associated with MRI-based thrombolysis, even if
cardiac comorbidities were taken into account. For mortality at 3 months there
was a non-significant difference in favor of the MRI group (16% versus 23%;
n.s.). In multivariable analyses, mortality at 3 months was independently
associated with older age, higher stroke severity, brain edema with mass
effect, SICH and pneumonia and coronary artery disease. Neither mortality nor
independent outcome was influenced by initial imaging modality. Thrombolysis
based on multimodal MRI is associated with reduced rates of SICH and early
death. Our results suggest that these complications affect survival
principally in the acute phase after thrombolysis. However non-neurological
and especially cardiac comorbidities also influence survival after stroke and
are underrepresented in stroke patients undergoing MRI. Selection bias has to
be considered
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
C5 complement inhibition versus FcRn modulation in generalised myasthenia gravis
No full textBackground Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular junctions, leading to fluctuating muscle weakness. While many patients respond well to standard immunosuppression, a substantial subgroup faces ongoing disease activity. Emerging treatments such as complement factor C5 inhibition (C5IT) and neonatal Fc receptor (FcRn) antagonism hold promise for these patients. However, the current landscape is hindered by a paucity of comparative data that is crucial for treatment decisions. Objective This study aims to compare the effectiveness and safety of C5IT and FcRn antagonists in a real-world setting. Methods A retrospective analysis of 153 MG patients from 8 German specialised MG centres receiving either C5IT (26 eculizumab, 80 ravulizumab) or efgartigimod (47 patients) was conducted. Propensity score matching (PSM) was employed to compare changes in MG-specific outcome parameters within the first 6 months after treatment initiation, along with safety profiles and concomitant MG therapy. Results Both treatment strategies led to rapid clinical improvements and substantial reductions in prednisolone doses. However, insufficient response was noted in 20%–49.1% of patients based on Quantitative MG and MG Activities of Daily Living (MG-ADL) scores. We did not identify any new safety concerns. After PSM, 40 patients remained in each group. In both cohorts, reductions in MG-ADL as prespecified primary study endpoint were comparable. Moreover, analyses of secondary outcome parameters demonstrated similar results for C5IT versus FcRn. Conclusion In contrast to current meta-analyses and indirect comparisons of clinical trial data, our real-world study demonstrates comparable efficacy and safety of C5IT and FcRn antagonism in MG
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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