1,720,961 research outputs found
Morphometry of the proximal femoral canal analyzed by a new mathematical model
No full textMany studies have analised the morphometry of the proximal meddulary canal of the femur. The knowledge of the shape and size of the femoral canal is needed to obtain maximum fitting of the custom stem with the internal geometry of the femur when it is implanted. We studied the morphometry of the proximal medullary canal in 70 cadaveric femurs. The femora were CT scanned in both the axial and coronal plane allowing 3D reconstructions. a mathematical model was applied to this data, and the results were then compared with those obtained by measurement from standard radiographs. We found that the median portion of the proximal extremity of the femur showed the highest degree of procurvation. On the frontal plane, the uppermost portion of the medullary canal made an inward curve cranially and an outward curve caudally. The results of our studies indicate that no definite information on the morphometry of the proximal femoral medullary canal can be obtained from radiograph
Studio artrografico dell’inserzione capsulare sul collo glenoideo. Correlazioni clinico-radiografiche
No full textMorphometry of proximal humerus end
No full textLittle is known about the spatial geometry of the medullary canal of the humerus. This may explain why the humeral prostheses are presently made by means of the graphical techniques used for femural prostheses.
Furthermore, no mathematical models have been used to study the shape of the humeral medullary canal.
Material and methods. We have calculated, on standard radiographs the values of the flare index and the curvature radius of 70 dried humeri. The curvature radius of the proximal medullary canal of the same humeri
was determined applying a mathematical model to the data obtained by means of measures carried out on axial CT scans (by calculating the barycentres of the scans) and on three-dimensional reconstructions. The
values obtained were compared with those calculated on radiographs. The results obtained with our technique were then compared with those obtained from data.
Results. Our results show that no precise information on the spatial geometry of the humeral medullar canal can be obtained form radiographic studies. We also found that the proximal half of the humeral canal either
sharply procurves, though to a mild extent, and then gradually becomes
rectilinear, or gradually reaches the largest amount of curvature. On the
frontal plane, the upper half of the medullar canal is cranially inward
curved and distally outward curved, or vice versa.
Conclusions. The results of this study give new information on the spatial geometry of the humeral medullary canal. Hence, while it seems impossible to improve beyond a certain limit the "fill" of the femural
canal achieved by custom made prostheses, the typical morphometry of the humeral canal may lead to further improvements of the "fit" between the implant and the canal, compared with the currently available prostheses
Makeup Pencils in Plastic Surgery
No full textDescription of a useful trick in plastic surgery plannin
Morfometria dell'estremità prossimale dell'omero
No full textLa morfometria del canale midollare dell'omero, a differenza di quella
del canale femorale, è stata scarsamente studiata.
Gli studi morfometrici hanno analizzato soprattutto il grado di retro
versione della testa omerale rispetto al piano transepicondiloideo (Boileau
et al., 1991) o l'articolazione omero-ulnare (Amis et al., 1977; Shiba et
al., 1988) poichè, nel corso dell'impianto di una protesi di spalla, la retro-
versione della superficie articolare viene calcolata riferendosi all'asse
dell'avambraccio a gomito flesso.
Neer (1990) ha riscontrato un'ampia variabilità individuale del canale
midollare omerale, sottolineando che il riempimento cavitario, ottenuto con
press-fit o cemento acrilico, e alia base della longevità della protesi. Roberts
et al. (1991) e Ballmer et al. (1993) hanno studiato con metodi radiografici, rispettivamente, I'asse omerale del terzo prossimale in 39 omeri e la
morfometria del canale midollare prossimale in 10 omeri all’interno dei
quali era stato inserito un cilindro a press-fit. Horsman et al. (1977) hanno studiato radiograficamente il canale midollare omerale rilevando una
netta variabilità delle dimensioni in funzione del grado di rotazione
dell'omero.
Scarse sono le informazioni riguardo all'andamento spaziale dei canale
omerale, sebbene le protesi di spalla costruite su misura vengano impiantate da oltre dieci anni (Figgie et al., 1992). Tali protesi vengono attualmente costruite utilizzando le stesse tecniche di calcolo grafico del fit usale per Ie protesi femorali. Ne, infine, vi sono studi sul canale omerale che
si sono avvalsi di modelli matematici
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
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