1,720,958 research outputs found
Heterogeneous pathologies associated with dementia in Parkinsonism share a prion-like spreading mechanism
No full textCognitive alterations accompany or follow motor disorders in subjects with Parkinsonism. The canonical phenotype of the Parkinson's disease Dementia (PD-D) or Lewy Body Dementia (LBD) includes deficit of attention, executive and visuospatial functions, and presents often with apathy, hallucinations, delusions, excessive daytime sleepiness, or sleep disorders. However, the clinical expression may overlap with other neurodegenerative diseases associated with cognitive disorders. Thus, while clinicians rely on phenomenological patterns to infer the disease causing the cognitive impairment, the inference is weakened by the heterogeneous clinical expression of the disease. In addition, recent post-mortem studies seem to undermine the supposed pathology-phenotype coherence, making it more and more unreliable the diagnosis based on symptoms. The lack of coherence between phenotype and pathology may support the speculation about a common mechanism underlying the progression of the disease. While it is very likely that a distinct, specific causal event determines the disease itself, the progression might well follow common patterns. A number of observations suggest that progressive diseases, which cause cognitive impairment, share a prion-like mechanism. A seeding process is supposed to account for the spreading of the lesion
Therapeutic hypothermia for acute stroke
No full textOn a theoretical background, hypothermia surmounts pharmacological neuroprotection by providing simultaneous effects on several mechanisms potentially relevant in the postischemic maturation of the damage. Measurements of the infarct size in animal models reveal that mild hypothermia is probably one of the most effective and documented neuroprotective intervention, both in focal and global ischemia models. As expected, hypothermia is more effective, and the results more consistent, when the time window for initiation of treatment is shorter than 6 h, with an apparent correlation between effect size and time window in the range of 0–6 h. There seems to be also an inverse relationship between temperature depth and reduction in infarct size. Mild hypothermia, such as cooling by 1°C or 2°C, is still associated with a noteworthy 20%–30% infarct size reduction. A few controlled studies in patients with ischemic stroke show feasibility and safety of cooling to a target temperature of 33°C–34°C, for 12 or 24 h, associated with antishivering pharmacological treatment. Hypothermia can be safely induced in acute stroke patients by infusion of iced saline, and the target temperature can be obtained and maintained by either surface or endovascular cooling, followed by controlled rewarming. Multicenter, randomized, phase III trials are ongoing to test the efficacy of the procedure
A new case of brainstem variant of posterior reversible encephalopathy syndrome: clinical and radiological features.
No full text
Treatment of Perimenstrual Migraine with Triptans. an Update
No full textPure menstrual migraine (PMM) and menstrually related migraine (MRM) are difficult challenges in migraine management. Triptans are a class of highly selective serotonin receptor agonists, which interfere with the pathogenesis of migraine and are effective in relieving the associated neurovegetative symptoms. In recent years triptans have been extensively proposed for the treatment of severe, disabling, and recurrent perimenstrual migraine attacks. This review summarizes the different levels of recommendations for the use of triptans in the treatment of perimenstrual migraine. This review is also intended to offer an updated reasonable guide to physicians treating perimenstrual migraine in daily practice
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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