1,721,008 research outputs found
Cardiac myxoma with glandular elements metastatic to the brain 12 years after the removal of the original tumor
Going Beyond Counting First Authors in Author Co-citation Analysis
The 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
“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
We 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
Motor cortex excitability in Alzheimer's disease: A transcranial magnetic stimulation study
Motor deficits affect patients with Alzheimer's disease only at later stages. Recent studies demonstrate that the primary motor cortex is affected by neuronal degeneration accompanied by the formation of amyloid plaques and neurofibrillary tangles. It is conceivable that neuronal loss is compensated by reorganization of the neural circuitries occurring along the natural course of the disease, thereby maintaining motor performances in daily living. Cortical motor output to upper limbs was tested via motor-evoked potentials from forearm and hand muscles elicited by transcranial magnetic stimulation of motor cortex in 16 patients with mild Alzheimer's disease without motor deficits. Motor cortex excitability was increased, and the center of gravity of motor cortical output, as represented by excitable scalp sites, showed a frontal and medial shift, without correlated changes in the site of maximal excitability (hot-spot). This may indicate functional reorganization, possibly after the neuronal loss in motor areas. Hyperexcitability might be caused by a dysregulation of the intracortical GABAergic inhibitory circuitries and selective alteration of glutamatergic neurotransmission. Such findings suggest that motor cortex hyperexcitability and reorganization allows prolonged preservation of motor function during the clinical course of Alzheimer's disease
Effects of lamotrigine on nocturnal sleep, daytime somnolence and cognitive functions in focal epilepsy
OBJECTIVES:
The aim of our study was to evaluate possible changes in nocturnal sleep, daytime somnolence and cognitive functions induced by add-on therapy with lamotrigine (LTG).
MATERIAL AND METHODS:
Thirteen patients affected by seizures resistant to common antiepileptic drugs (AEDs) underwent nocturnal polysomnographic monitorings, daytime somnolence evaluations and a neuropsychological battery before and after 3 months of treatment with LTG.
RESULTS:
With LTG therapy we observed a significant increase in REM sleep and a significant reduction in the number of entries into REM and stage shifts. No significant correlation was observed between the decrease in nocturnal epileptiform activity and the increase in REM sleep. Other sleep parameters were unmodified. No significant changes were observed in daytime somnolence and in cognitive performances.
CONCLUSION:
LTG may produce positive effects on epileptic seizures and interictal abnormalities without interfering negatively on REM sleep, with improvement of sleep stability and without changes in daytime somnolence and neuropsychological performances. For these reasons it could be an important drug for improving epileptic patients' quality of life
Immunità nuturale "tegente" anche nel flusso lagrimale
Abstract
Experimentall research on the rolc or
thc « tcgent» immune sytem of thc eye, par-
ticularly as rcgards sccretory IgA, has bcen carricd out, obtaining significant results and evi-
dencing positive, hitherto unknown corrclations.
Between implications and derivable applications
that conccrning thc possibility of prevention,
especiall as a function of early screening of
«predisposed» patients, and hence fairly easily
identifiable thanks to a straightforward examination which has been applied here
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