1,720,958 research outputs found
Real time visualization of femoroacetabular impingement and subluxation using 320-slice computed tomography
No full textWe visualized extreme ranges of motion of the hip and located femoroacetabular impingement (FAI) and subluxations using 4dimensional (D) volume computed tomography (CT). In dynamic 4D CT, 30 patients with hip pain (>3 months) and positive clinical and radiological signs of impingement were prospectively analyzed. The investigations were performed in flexion, abduction, and external rotation. The accuracy of the CT visualization of FAI was compared with the intraoperative findings during surgical dislocation, which served as the gold standard. Compared to the intraoperative visualization of FAI, the dynamic CT images showed a high degree of accuracy. 4D CT is a suitable method to dynamically visualize the functional consequences of anatomical FAI pathologies. The location of impingement can be accurately determined, and when combined with information about possible labral tears and chondral damage supplied by magnetic resonance arthrography, allows the surgeon to select the optimal surgical access and plan the required operation for minimal invasiveness
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
Reconstruction of the native hip center performing primary and revision total hip arthroplasty
No full textEs werden sowohl alters- als auch geschlechterspezifische Parameter des
Beckens dargestellt, die zum Teil signifikant differieren. Die azetabuläre als
auch koxale femorale Orientierung und Lokalisation wird von diesen
Einflussgrößen als auch vom funktionellen Sagittalprofil bestimmt. In der
Primärendoprothetik werden diese Unterschiede weitestgehend vernachlässigt
aufgrund des hohen Freiheitsgrades der möglichen ROM der Prothese. Die
Rekonstruktion der Pfannenneigung in der Frontalebene ist in der überwiegenden
Mehrheit nicht zu gewährleisten, da Stabilitätskriterien, Abriebverhalten und
potentielle Impingementsyndrome berücksichtigt werden müssen.
Navigationsassistierte Operationsverfahren können bei definierter Zielgröße
die Streubreite der Hüftpfannenpositionierung reduzieren, einem funktionellen
Ansatz wird diese Methodik bei unterschiedlichen Sagittalorientierungen des
Beckens nicht gerecht. Die Implantation des femoralen Ersatzes sollte
adjustiert zum azetabulären Ersatz erfolgen. Diese Forderung kann nicht für
alle anatomischen Varianten und alle Prothesenmpodelle erfüllt werden. Femoral
ist die achsgerechte Positionierung und Antetorsionsstellung mit Auswirkung
auf das femorale Drehzentrum des Implantates durch manuelle
Markraumreferenzierung erheblich fehlerbehaftet, so dass auch hier ein
funktionelles Malalignement intraoperativ nicht detektiert werden kann.
Zusätzlich zur rotatorisch justierten Antetorsionsstellung kann sich eine
Anteriorverlagerung des femoralen Drehzentrums durch sagittale
Schaftmalpositionierungen ergeben und eine funktionelle Antetorsion
resultieren, die die Funktion und Hüftkontaktkraft ungünstig beeinflussen.
Fehlerquellen können in der Primär- und Revisionsendoprothetik auch
resultieren, wenn eine unzureichende knöcherne Deckung des Implantates,
vornehmlich der Pfannenkomponente vorliegt. Dieses Risiko besteht bei einer
Veränderung des azetabulären Rotationszentrums, bei der Nutzung
überdimensionierter Implantatgrößen und bei größeren azetabulären
Pfeilerdefekten resp. pathologischen Orientierungen des Azetabulums. Unter
Ausschluss anderer Ursachen ist eine resultierende Impingementsymptomatik für
einen Teil der funktionell schlechten Ergebnisse und der schmerzhaften
Zustände nach hüftendoprothetischer Versorgung verantwortlich. Die
Orientierung des Implantates und somit die Adjustierung des Drehzentrums ist
aufgrund modularer Lösungen in der Revision femoral gut umsetzbar.
Azetabulumseitig werden bei Destruktion des originären Hüftzentrums heute auch
zunehmend modulare Systeme genutzt, um die Rekonstruktion defektabhängig bei
gleichzeitig sicherer Implantatverankerung zu gewährleisten.Both age and sex-specific parameters of the pelvis are represented, which
differ partially significant. The acetabular and femoral neck orientation and
localization are determined by these measured variables and by the functional
pelvic tilt. In primary hip arthroplasty these differences are mostly
neglected due to the high degree of freedom of the artificial range of motion.
The anatomical reconstruction of the cup inclination and anteversion is not
always possible and limited by conditions of stability, wear debris and
expected impingement syndromes. Navigation-assisted operation procedures can
reduce the spread of the malpositioning of the cup but a functional impact
including the pelvic rotation is currently not available. The implantation of
the femoral stem should follow with respect to the orientation of the
acetabular component. This demand cannot be performed for all anatomical
variants and all prosthetic devices. The accurate femoral stem insertion using
the endofemoral canal as a reference and the antetorsion of the implant with
effect on the femoral hip center are difficult to control in a bi-plane view,
so that a functional malalignement cannot be precisely detected
intraoperatively. Additionally to the adjusted rotation of the stem a sagittal
tilt may occur with influence on the femoral hip center and resulting
functional antetorsion, which affects the function and hip contact force
unfavourably. A dissatisfying outcome in primary and revision arthroplasty can
also result, if an insufficient osseous coverage of the implant is present,
especially on the acetabular side. This risk exists in pathological
orientations of the native acetabular cavity with a change of the rotational
center, with the use of oversized implants and with larger acetabular column
defects. Excluding other causes a resulting impingement syndrome is
responsible for a part of the functional disability and the painful outcome
after endoprosthetic treatment. The orientation of the implant and the
adjustment of the hip center are accurately reproducable due to modular
solutions in the femoral revision. On the acetabular side modular systems are
also increasingly used in enlarged deficiencies, to enable the reconstruction
of bony defects combined with a safe implant anchorage
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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