1,720,960 research outputs found
Piezoelectric surgery: twenty years of use
No full textThe use of ultrasonic vibrations for the cutting of bone was first introduced two decades ago. Piezoelectric surgery is a minimally invasive technique that lessens the risk of damage to surrounding soft tissues and important structures such as nerves, vessels, and mucosa. It also reduces damage to osteocytes and permits good survival of bony cells during harvesting of bone. Piezoelectric surgery was first used by oral and maxillofacial surgeons for osteotomies, but recently some specific applications in neurosurgery and orthopaedics have been proposed. We review the different applications of piezoelectric surgery
Piezoelectric surgery: Twenty years of use
No full textThe use of ultrasonic vibrations for the cutting of bone was first introduced two decades ago. Piezoelectric surgery is a minimally invasive technique that lessens the risk of damage to surrounding soft tissues and important structures such as nerves, vessels, and mucosa. It also reduces damage to osteocytes and permits good survival of bony cells during harvesting of bone. Piezoelectric surgery was first used by oral and maxillofacial surgeons for osteotomies, but recently some specific applications in neurosurgery and orthopaedics have been proposed. We review the different applications of piezoelectric surgery
Elaborazione di un supporto informatico per la valutazione del carico assistenziale in RSA e la ridistribuzione delle risorse
No full text
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
Design, morphometry and development of the secondary osteonal system in the femoral shaft of the rabbit.
No full textThe architecture of the diaphyseal bone is closely correlated with the cortical vessel network, whose pattern
develops in the course of growth. Various methods have been applied to clarify the three-dimensional anatomy
of the cortical canal system, but there is still disagreement about the geometry, blood supply, flux dynamics and
factors controlling canal geometry during bone growth and remodeling. A modification of the currently employed
dye-injection method was applied to study the vessel network of the whole hemi-shaft of the rabbit femur in
mature bones (8-month-old rabbits) and growing bones (1.5-month-old rabbits). The cortical vascular tree of the
hemi-shaft of the femur was injected with black China ink and observed in full-thickness specimens of the cortex.
The same specimens were then processed for histology. A comparative study of the middle diaphysis (mid-shaft)
with the distal extremity (distal shaft) was performed in both young and old rabbit femurs. The longitudinally
oriented pattern of the vessel network was seen to develop in the diaphysis of mature femurs, while at the
extremity of the shaft of the same specimen the network showed a reticular organization without a dominant
polarization. The vessels were significantly higher in the mid-shaft than in the distal shaft of the old femurs
(
P
< 0.0001), as was their diameter (
P
< 0.05). In the group of young rabbits at mid-shaft level the longitudinally
oriented pattern of the vessel network was not yet completely developed, without their being significant differences
in length and diameter between the mid-shaft and distal shaft. The differentiation of the mid-shaft from
the distal shaft was confirmed histologically by the presence, in the latter, of longitudinal calcified cartilage septa
between osteons. This pattern of structural organization and development of the intracortical vascular network
has not been previously reported. The cells primarily involved in polarization of the remodeling process were the
osteoclasts at the top of the cutting cones advancing from the proximal and distal metaphyses toward the midshaft.
This suggests, first, a relationship with the longitudinally oriented structures already present in the
cortex near the metaphysis (the calcified cartilage septa) and then with the columns of interosteonic breccia, which
were formed as a secondary effect of the longitudinal polarization of the remodeling process. Our observations
did not enable us to substantiate the model of two different systems, one of longitudinal vessels (Havers) and the
other of connecting transversal vessels (Volkmann), but suggested instead that there is a network whose loops
lengthen in the direction of the major bone axis in the course of growth and secondary modeling. The associated
morphology supported the view that the type of structural organization of the tubular bone cortex is primarily
determined by an inherited constitutional factor rather than by mechanical strains.
Key words
bone architecture; cortical bone; cortical vessel network; Havers’ and Volkmann’s canals
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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