1,721,014 research outputs found
MRI of cortical lesions and its use in studying their role in MS pathogenesis and disease course
No full textCortical grey matter (GM) demyelination is present from the earliest stages of multiple sclerosis (MS) and is associated with physical deficits and cognitive impairment. In particular, the rate of disability progression in MS, both in the relapsing and progressive phases, appears to be strictly associated with degenerative GM demyelination and diffuse cortical atrophy. In the last decade, several histopathological studies and advanced radiological methodologies have contributed to better identify the exact involvement/load of cortical pathology in MS, even if the specific inflammatory features and the precise cell and molecular mechanisms of GM demyelination and neurodegeneration in MS remain still not fully understood. It has been proposed that a combined neuropathology, imaging and molecular approach may help to define a more detailed characterization and precise assessment of the heterogeneous features of GM injury and inflammation in MS. This, in turn, will possibly identify specific imaging and biohumoral (cerebrospinal fluid/serum) correlates of cortical pathology that may have an important role in predicting and monitor the disease evolution. This article is protected by copyright. All rights reserved
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
Surface-in pathology in multiple sclerosis: a new view on pathogenesis?
No full textWhile multiple sclerosis can affect any part of the CNS, it does not do so evenly. In white matter it has long been recognized that lesions tend to occur around the ventricles, and grey matter lesions mainly accrue in the outermost (subpial) cortex. In cortical grey matter, neuronal loss is greater in the outermost layers. This cortical gradient has been replicated in vivo with magnetization transfer ratio and similar gradients in grey and white matter magnetization transfer ratio are seen around the ventricles, with the most severe abnormalities abutting the ventricular surface. The cause of these gradients remains uncertain, though soluble factors released from meningeal inflammation into the CSF has the most supporting evidence. In this Update, we review this 'surface-in' spatial distribution of multiple sclerosis abnormalities and consider the implications for understanding pathogenic mechanisms and treatments designed to slow or stop them
Dendritic cells in multiple sclerosis lesions: maturation stage, myelin uptake, and interaction with proliferating T cells.
No full textIntracerebral regulation of immune responses
No full textMajor progress has been made over the last years in our understanding of the mechanisms underlying immune privilege and immune surveillance of the central nervous system (CNS). Once considered a passive process relying only on physical barriers, immune privilege is now viewed as a more complex phenomenon, which involves active regulation of immune reactivity by the CNS microenvironment. Evidence has also emerged that the immune system continuously and effectively patrols the CNS and that dysregulated immune responses against CNS-associated (exogenous or self) antigens are involved in the pathogenesis of various neurological diseases. In this article we shall briefly review current knowledge of how the immune response is regulated locally in the CNS and which cell types and molecular mechanisms are involved in shaping intracerebral immune responses
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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