1,720,965 research outputs found
Recurrent episodes of syncope in a patient with cerebral arteriovenous malformation
No full textAs there are a number of possible causes of syncope, differentiation between cardiovascular disease, neurogenic disease and other disorders is mandatory. Cerebral arteriovenous malformations (AVMs) are tangled anastomoses of blood vessels of varying calibre in which arteriovenous shunting occurs in a central nidus, which is the area towards which multiple feeding arteries converge and from which enlarged veins drain. We describe a clinical case of syncope caused by a large AVM discovered in a 66-year-old woman. The symptoms were probably related to an epileptogenic mechanism since the syncope disappeared following the administration of antiepileptic therapy. The anatomical, pathological and clinical aspects of AVMs are discussed
When a pregnancy required a neurological consultation: a case report
No full textPosterior reversible encephalopathy syndrome (PRES) is a transient clinical and neuroradiological syndrome characterized by clinical signs and symptoms including hypertension, seizures, altered mental status, headache, and vision changes and characteristic features on head computed tomography (CT) or magnetic resonance imaging (MRI) scan. PRES is most commonly reported in the literature in association with obstetric patients suffering from pre-eclampsia or eclampsia. In the acute setting, it is important to recognize the characteristics of PRES and immediately treat patients' emerging conditions that are hypertension and seizures. The following case report describes a pregnant patient who presented clinical characteristics of eclampsia with recurrent episodes of seizure and hypertension complicated by PRES. This case highlights the importance of early recognition and treatment of this condition that is usually transient and completely reversible, but can lead to ischemic injury and irreversible brain damage. Clin Ter 2012; 163(6):487-49
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
Role of multidetector CT in the recognition of hyperdense middle cerebral artery sign (HMCAS) in patients with acute cerebral ischaemia: correlation with DWI-MRI sequences and clinical data
No full textPurpose The aim of this study was to verify the sensitivity and specificity of the hyperdense middle cerebral artery sign (HMCAS) obtained by multidetector computed tomography (CT) in predicting acute stroke, using diffusion-weighted (DW) magnetic resonance imaging (MRI) as a reference. The location of the HMCAS, the extension of the ischaemic lesion and its prognostic value were also assessed. Materials and methods The CT examinations of 654 patients with symptoms related to acute cerebral stroke were retrospectively reviewed. DW-MRI confirmed recent stroke in 175 patients. Two expert neuroradiologists analysed the CT examinations of these patients in four phases. Sensitivity, specificity and interobserver reliability was evaluated. Patients were divided into three groups according to the HMCAS site (M1-M2-M3) and the Alberta Stroke Program Early CT Score (ASPECTS) on DW-MRI was calculated. The ASPECTS average score was correlated with the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) at 3 months. Results In 41 patients, the presence of HMCAS was confirmed (71 % sensitivity; 100 % specificity; Interobserver reliability k, 84 %). An inverse correlation was found by comparing the ASPECTS and NIHSS scores (Rsq = -0.206). After logistic regression analysis, HMCAS was found to be independently associated with a poor outcome (mRS >2) at 3 months after adjusting for age, NIHSS on admission, risk factors and aetiology of stroke. Conclusions Our study demonstrated that HMCAS obtained with multidetector CT can be detected in more than 70 % of patients with large acute ischaemic lesion and it is an unfavourable prognostic sign. © 2014 Italian Society of Medical Radiology
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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