1,720,959 research outputs found
Analisi di post processing delle risonanze magnetiche cerebrali di bambini con esiti di Shaken Baby Syndrome: studi di DTI del corpo calloso
Full text linkBackground. The Shaken Baby Syndrome (SBS) is a leading cause of morbidity and mortality among abused children. Its pathogenesis is characterized by the presence of a mechanical damage responsible of focal lesions, which adds a metabolic damage resulting in widespread damage of the white matter (WM).
Aim. This study used diffusion tensor imaging (DTI) to examine white matter (WM) abnormalities of corpus callosum (CC) in infants with SBS in order to asses how WM microstructure may reflect axonal damage and correlate with clinical outcomes.
Methods. We collect DTI scans from 5 infants (age range: 23 months – 6 years 5 months) after months from the diagnosis of SBS (18 months up to 6 years); the WM of the CC has been analyzed using a probabilistic model.
Clinical variables and conventional imaging findings were analyzed in relation to outcome. Cognitive outcomes were assessed by the administration of the scales of development Griffiths (Griffiths Mental Development Scales-GMDS) or the Wechsler scales for children older than 4 years. Fractional anisotropy ( FA ) , axial diffusivity (AD ) , and radial diffusivity ( RD ) were calculated for each of the seven regions in which it was divided the corpus callosum, according to the Wiltelson model.
Results . The five children studied (3 males and 2 females , mean age = 48 months, average time since diagnosis = 42 months) had normal cognitive development in 3 cases and below normal in 2 cases . The 3T MRI performed during follow-up in the medium-long term showed damage to the white matter only in one case. Reduced FA values were measured in diffuse regions of WM in all children with SBS, with major impairment in children who had a deviation below the norm of cognitive development, but with altered values also in children that at present showed normal development .
Conclusions. Findings support the unique role of new DTI techniques, beyond conventional imaging, in the evaluation of microstructural WM injury of SBS. This preliminary study confirms the important role of DTI tractography for its both therapeutic and prognostic implication, confirming the usefulness of more extensive and sophisticated research in this are
Applicazione della DTI nella valutazione degli esiti neurobiologici nella sindrome del bambino scosso
No full textSpontaneous involution of diffuse fibrous dysplasia of paranasal sinuses
No full textWe report the case of a 25-year-old patient, diagnosed at age 10, with diffuse fibrous dysplasia of the paranasal sinuses, an extremely rare idiopathic condition. This diagnosis is possible only by cerebral computed tomography (CT), cerebral and anterior skull base magnetic resonance imaging (MRI), and histopathology. Surgical treatment is common. This boy had mild symptoms: moderate headache in the morning that did not affect his daily activity, and rhinitis, partially responsive to medication. The neurologic examination was abnormal. Radiographs, CT, and MRI showed a diffuse mass in the paranasal sinuses which had a histopathological diagnosis of fibrous dysplasias. The family refused to refer the patient to surgery. The boy has been monitored annually for 15 years. He has remained asymptomatic without headache since age 11, with normal, general and neurologic examinations. Serial MRIs showed a spontaneous partial involution of the mass
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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