1,721,033 research outputs found
Pathophysiological mechanisms and experimental pharmacotherapy for L-Dopa-induced dyskinesia
Full text linkL-dopa-induced dyskinesia (LID) is the most frequent motor complication associated with chronic L-dopa treatment in Parkinson’s disease (PD). Recent advances in the understanding of the pathophysiological mechanisms underlying LID suggest that abnormalities in multiple neurotransmitter systems, in addition to dopaminergic nigrostriatal denervation and altered dopamine release and reuptake dynamics at the synaptic level, are involved in LID development. Increased knowledge of neurobiological LID substrates has led to the development of several drug candidates to alleviate this motor complication. However, with the exception of amantadine, none of the pharmacological therapies tested in humans have demonstrated clinically relevant beneficial effects. Therefore, LID management is still one of the most challenging problems in the treatment of PD patients. In this review, we first describe the known pathophysiological mechanisms of LID. We then provide an updated report of experimental pharmacotherapies tested in clinical trials of PD patients and drugs currently under study to alleviate LID. Finally, we discuss available pharmacological LID treatment approaches and offer our opinion of possible issues to be clarified and future therapeutic strategies
Paleoecological insights on latest oligocene-early miocene planktonic foraminifera from the J-anomaly ridge (IODP hole U1406A)
Full text linkThis paper focuses on a paleoecological study conducted on planktonic foraminifera from upper Oligocene-lower Miocene deposits of the J-Anomaly Ridge (North Atlantic Ocean). Paleoclimatic studies are crucial to better comprehend how climatic changes occurred in the past and how they might influence global climate in the next few decades. Oceanic currents are the predominant vehicle for heat transport across the globe and therefore organisms living within the water mass can supply much information on paleoceanographic settings. In total, 53 samples from IODP Hole U1406A were selected in the core interval 96-24 CCSF-M to perform statistical analyses (R-mode cluster analysis, principal component analysis) to describe ecogroup distribution and a paleoclimatic curve based on shallow dwelling taxa. The species have been subdivided into three ecogroups referring to recent studies on planktonic foraminiferal paleoecology. The statistical analyses allowed a preliminary screening of the distribution of the foraminiferal assemblages in the biozonal interval of O7–M3. The ecogroup distribution curves revealed the behavior of each group along the section, highlighting the interconnection among the various habitats. Finally, the abundance of the surface taxa was used to trace a paleoclimatic curve (SDPC) describing the superficial water variations. Those results were compared with the Alkenone Sea Surface Temperature (SST) record from IODP Site U1404 and the δ18O North Atlantic stack from the literature. This comparison showed a good match among the foraminiferal and geochemical data, allowing the correlation of SDPC and SST minima with well-known glacial events of the North Atlantic Ocean. This study supports the potential of census data of planktonic foraminifera in paleoclimatic studies when geochemical data are not available
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
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