1,720,974 research outputs found
Cerebral transverse sinus morphology as detected by MR venography in patients with chronic migraine.
No full textTo clarify the frequency and characteristics of altered transverse sinus morphology in a series of consecutive patients with chronic migraine. As terminology, neuroradiological techniques and patient selection differ widely across various studies, reliable, reproducible information is lacking on the frequency of cerebral transverse sinus asymmetry as measured by cerebral magnetic resonance venography in patients with chronic migraine. We assessed the frequency and characteristics of transverse sinus asymmetries and their correlation with the chronic migraine phenotype in a blind, cross-sectional magnetic resonance venographic study in a series of 83 consecutive patients with chronic migraine. After excluding mild (≤ 10%) physiological differences in transverse sinus diameter, we found magnetic resonance venographic evidence of altered transverse sinus morphology in 50.6% of the patients: 16.9% had moderate transverse sinus asymmetry (≤ 50%), 24.1% severe asymmetry (>50%), and 9.6% aplasia. Among the tested risk factors for migraine chronification, analgesic consumption, anxiety, and high systolic blood pressure were more frequent in patients with transverse sinus aplasia than in those without. Advanced magnetic resonance venographic techniques used in strictly selected subjects disclose transverse sinus asymmetries in as many as 50.6% of patients with chronic migraine, even when mild differences in physiological caliber are excluded. The unexpected correlation between transverse sinus aplasia and some risk factors for migraine chronification requires confirmation in larger studies. © 2012 American Headache Society
Depressed intracortical inhibition after long trains of subthreshold repetitive magnetic stimuli at low frequency
No full textObjective: Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability. These effects outlast the rTMS train, and range from inhibition to facilitation according to the variables used for rTMS. Several studies have demonstrated short and long-term effects on motor evoked potential (MEP) size, whereas the effects on intracortical inhibition (ICI) and facilitation (ICF) are still unclear. We investigated short- (1–15 min), intermediate- (16–30 min), and long-term (6 h) effects on intracortical excitability. Methods: Fourteen healthy subjects were stimulated with rTMS trains of 900 pulses (1 Hz, 90% resting motor threshold (rMTh)), delivered over the primary motor cortex and the occipital area. MTh, MEP size, silent period, intracortical inhibition at short (ICI) and long inter-stimulus intervals, and ICF were tested before and after rTMS. Results: ICI was reduced 16–30 min after 1 Hz rTMS trains over the primary motor area, whereas the other response variables remained unchanged. The ICI reduction at 16–30 min was reproducible on different days in the same subjects; it was absent at 6 h and after stimulation of the occipital area. Conclusions: Subthreshold 1 Hz rTMS decreases ICI by reducing the excitability of intracortical inhibitory interneurones or by altering the electrical properties of the facilitatory chain of neurons responsible for the I waves
An observational study on electrolyte disorders in the acute phase of ischemic stroke and their prognostic value
No full textData on electrolyte disorders in neurological conditions and in acute stroke are somewhat scanty and not easily compared. In our Stroke Unit we studied patients hospitalized within six hours of the onset of an acute ischemic stroke and recorded their demographic and clinical data. Blood test results were recorded before any pharmacological therapy. A total of 475 individuals (256 males, 219 females; age range: 14-96 years) treated over a period of 18 consecutive months, were selected. According to a multiple logistic regression analysis, the baseline National Institutes of Health Stroke Scale (NIHSS) score (odds ratio [OR] = 1.33; 95% confidence interval [CI]: 1.22-1.44) and alterations in serum sodium (OR = 6.89; 95% CI = 1.94-24.40) were associated with higher odds of death. Based on an ordinal logistic regression analysis, the baseline NIHSS score (OR = 1.07; 95% CI = 1.03-1.10) and baseline hypernatremia (OR = 9.69; 95% CI = 1.55-60.69) were related to early neurological worsening. Our work suggests an association between serum sodium alterations and mortality, and between high sodium levels and neurological clinical impairment, in the acute phase of an ischemic stroke. (C) 2011 Elsevier Ltd. 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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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