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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
Morbidity and mortality in patients in cardiogenic shock treated with the left ventricular microaxial pump Impella®
No full textDer kardiogene Schock ist trotz Fortschritten in der Therapie weiterhin mit einer
hohen Mortalität verbunden. Zur linksventrikulären Entlastung wurden daher
temporäre mechanische Kreislaufunterstützungssysteme wie die Impella®-
Mikroaxialpumpe entwickelt. Auch weil die bis dahin häufig verwendete IABP
keine Verbesserung von Hämodynamik und Mortalität nachweisen konnte.
Ziel dieser Studie war es, die Effektivität, Handhabung und Sicherheit der
Impella® bei Patient:innen im kardiogenen Schock zu evaluieren. Es sollten
verschiedene Gruppen bezüglich Morbidität und Mortalität analysiert werden, die
von der Mikroaxialpumpe profitieren können.
Es wurden retrospektiv Daten von 112 Patient:innen im kardiogenen Schock mit
Impella® in dem Zeitraum von Januar 2013 bis Juli 2015 in 2 Zentren
ausgewertet. Die Effektivität der Mikroaxialpumpe wurde anhand der
notwendigen Katecholamintherapie, Lactatwerte und anderer Laborparameter zur
Beurteilung der Organfunktion, sowie intensivmedizinischer Scores untersucht.
Außerdem wurden Impella®-assoziierte Komplikationen analysiert und die
intrahospitale, sowie 30-Tages-Mortalität in verschiedenen Gruppen ermittelt.
Die untersuchte Patient:innengruppe hatte ein medianes Alter von 73,0 Jahren
(61,0-79,0 Jahre). Die Basischarakteristika zeigten sich in der Gruppe reanimierter
und nicht-reanimierter Patient:innen (CPR+Schock vs. Schock) und in den
Subgruppen (Impella® 2.5 vs. CP, männlich (m) vs. weiblich (w), < vs. ≥ 75
Jahre) vergleichbar. Die häufigste Ursache des kardiogenen Schocks war mit
85,7% der akute Myokardinfarkt (43,8 % STEMI, 42,0 % N-STEMI). 86,6 % der
Patient:innen hatten eine relevante KHK, bei der Mehrzahl (53,6 %) bestand eine
3-Gefäß-KHK.
Für die Gesamtgruppe ließ sich tendenziell ein Abfall der notwendigen
Dobutamintherapie innerhalb der ersten 72 Stunden nach Impella®-Implantation
nachweisen (Implantation 333,3 μg/min (0-416,7 μg/min), 72h 250,0 μg/min (0-
416,7 μg/min) [p=0,07]), für Frauen war dies signifikant [p=0,02]. Außerdem
zeigte sich ein signifikanter Abfall der Lactatwerte unter Impella® (Implantation
2,5 mmol/l (1,0-6,25 mmol/l), 72h 1,0 mmol/l (1,0-2,0 mmol/l) [p=0,0002]).
Für reanimierte ließ sich im Vergleich zu nicht-reanimierten Patient:innen
(CPR+Schock vs. Schock) bei Impella®-Implantation ein erhöhter Noradrenalinund
Adrenalinbedarf [p=0,05/p=0,001], CardShock risk Score [p=0,02], sowie
tendenziell erhöhte Lactatwerte [p=0,08] und Leberversagen [p=0,15] beobachten.
Signifikant häufiger bestand eine maschinelle Beatmung [p<0,0001] und der
Verdacht eines hypoxischen Hirnschadens [p=0,0014]. Patient:innen mit Impella®
CP zeigten bei Implantation tendenziell eine erhöhte Noradrenalindosis (2.5 vs.
CP p=0,13) und CardShock risk Score (2.5 vs. CP p=0,08). Auch weibliche
Patient:innen hatten initial einen hohen Noradrenalinbedarf (m vs. w p=0,01).
Die Handhabung der Impella® war unkompliziert im Hinblick auf Implantation,
Reposition und technischen Umgang. Impella®-assoziierte Blutungen im Bereich
der Punktionsstelle traten selten auf (8,0 %), waren jedoch häufiger unter
Impella® CP (2.5 vs. CP p=0,03). Blutungen multifaktorieller Genese machten die
Transfusion von EK vor allem notwendig bei weiblichen Patientinnen (m vs. w
p=0,03) und unter Impella® CP (2.5 vs. CP p=0,006).
Die intrahospitale Mortalität der untersuchten Patient:innengruppe mit
kardiogenem Schock und Impella®-Unterstützung lag bei 58,9 %. Signifikant
erhöht war diese für Reanimierte (CPR+Schock vs. Schock 70,4 % vs. 48,3 %
[p=0,02]). Auch nach 30 Tagen war das Überleben für Patient:innen ohne
stattgehabte Reanimation besser (51,7 % vs. 31,5 % [p=0,009]). Zwischen den
Impella®-Modellen und in den anderen Subgruppen ließ sich kein Unterschied der
intrahospitalen und 30-Tages-Mortalität beobachten.
Insgesamt konnte die vorliegende Arbeit zeigen, dass die Impella®-
Mikroaxialpumpe ein sicheres und einfach handhabbares
Kreislaufunterstützungssystem für Patient:innen im kardiogenen Schock ist.
Bezüglich der Effektivität ergaben die Daten Hinweise für eine klinisch relevante
Verbesserung der Hämodynamik unter Impella®. Signifikante Unterschiede
zwischen den beiden Impella®-Modellen ließen sich trotz unterschiedlicher
Auswurfleistung nicht nachweisen. Die Bewertung des klinischen Effektes ist
allerdings durch die ohnehin hohe Mortalität des kardiogenen Schocks,
insbesondere der Gruppe reanimierter Patient:innen, erschwert. Demnach müssen
randomisierte kontrollierte Studien klären, welche Patient:innengruppe zu
welchem Zeitpunkt von einer Impella® profitiert und inwiefern das Outcome des
kardiogenen Schocks positiv beeinflusst werden kann.Despite advancements in therapy cardiogenic shock remains associated with a
high mortality. In order to achieve left ventricular unloading, temporary
mechanical circulatory support systems such as the Impella® microaxial pump
have been developed, especially considering the previously widely used IABP
failed to demonstrate improvements in hemodynamics and mortality in
cardiogenic shock. The objective of this study was to evaluate the effectiveness,
handling and safety of Impella® in patients in cardiogenic shock. Different groups
that could benefit from the microaxial pump were to be analyzed in terms of
morbidity and mortality.
Retrospective data from 112 patients in cardiogenic shock with Impella® from
January 2013 to July 2015 in two centers were analyzed. The effectiveness of the
microaxial pump was assessed based on the required catecholamine therapy,
lactate levels and other laboratory parameters for organ function evaluation as
well as intensive care scores. Additionally, Impella®-associated complications
were analyzed and intrahospital and 30-day mortality were determined in different
groups.
The investigated cohort had a median age of 73.0 years (61.0-79.0 years). Basic
characteristics were comparable between resuscitated and non-resuscitated
patients (CPR+Schock vs. Schock) and in subgroups (Impella® 2.5 vs. CP, male
(m) vs. female (f), < vs. ≥ 75 years). The most common cause of cardiogenic
shock was acute myocardial infarction at 85.7% (43.8% STEMI, 42.0%
NSTEMI). 86.6% had relevant coronary artery disease, with the majority (53.6%)
having three-vessel CAD.
Overall, a trend towards reduction in dobutamine therapy within the first 72 hours
after Impella® implantation was observed (Implantation 333.3 μg/min (0-416.7
μg/min), 72h 250.0 μg/min (0-416.7 μg/min) [p=0.07]), significantly for women
[p=0.02]. Additionally, a significant decrease in lactate levels with Impella® was
observed (Implantation 2.5 mmol/l (1.0-6.25 mmol/l), 72h 1.0 mmol/l (1.0-2.0
mmol/l) [p=0.0002]).
Compared to non-resuscitated patients (CPR+Schock vs. Schock), resuscitated
patients showed at Impella® implantation an increased need for noradrenaline and
adrenaline [p=0.05/p=0.001], CardShock risk Score [p=0.02] and a tendency
towards increased lactate levels [p=0.08] and liver failure [p=0.15]. Mechanical
ventilation [p<0.0001] and suspected hypoxic brain injury [p=0.0014] were
significantly more frequent. Patients with Impella® CP tended to have higher
noradrenaline doses (2.5 vs. CP p=0.13) and CardShock risk scores (2.5 vs. CP
p=0.08) at implantation. Female patients also initially had a high noradrenaline
requirement (m vs. f p=0.01).
The handling of Impella® was uncomplicated regarding implantation,
repositioning, and technical management. Impella®-associated bleeding at
puncture site was rare (8.0%), but more frequent with Impella® CP (2.5 vs. CP
p=0.03). Multifactorial bleeding required red blood cell transfusion especially in
female patients (m vs. f p=0.03) and during Impella® CP treatment (2.5 vs. CP
p=0.006).
The overall intrahospital mortality with Impella® support was 58.9%. This was
significantly higher for resuscitated patients (CPR+Schock vs. Schock 70.4% vs.
48.3% [p=0.02]). Even after 30 days, survival was better for patients without
resuscitation (51.7% vs. 31.5% [p=0.009]). No difference in intrahospital and 30-
day mortality was observed between Impella® models and within other
subgroups.
In conclusion, this study demonstrated the Impella® microaxial pump as a safe
and easily manageable circulatory support system for patients in cardiogenic
shock. Regarding effectiveness, the data suggested clinically relevant
improvement in hemodynamics during Impella® treatment. Despite different
ejection capabilities, no significant differences were observed between the two
Impella® models. However, evaluating the clinical effect is complicated by the
inherently high mortality of cardiogenic shock, especially in resuscitated patients.
Therefore, randomized, controlled trials are needed to determine which patient
group benefits from Impella® at which point in time and to what extent it
positively influences the outcome of cardiogenic shock
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
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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