1,720,984 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Contrôle des crises d'épilepsie par les ganglions de la bases: approches cliniques et expérimentales
No full textAs about one third of epileptic patients are resistant to antiepileptic drugs, and only 30% of them are candidates for resective surgery, it exists a great demand for the development of alternative surgical therapies. It has been shown in animal studies, that the basal ganglia and especially the substantia nigra (SN) are involved in the control of epilepsy. Clinical evidence, using either electrophysiological or imaging approaches, also supports the involvement of the basal ganglia in some epileptic syndromes. The influence of seizure spread into the basal ganglia in patients with focal epilepsies was investigated on the rate of secondary generalization. We showed that activation of the basal ganglia was associated with an inhibitory effect on seizure propagation, when seizures spread into the frontal lobe. The elucidation of inhibitory mechanisms in epilepsy may open a new approach for therapeutic strategies such as electrical deep brain stimulation. First open case series, investigating deep brain stimulation of the basal ganglia to suppress epileptic seizures, showed encouraging results in some patients. However, more preclinical studies are mandatory to investigate the optimal stimulation parameters. The aim of our experimental approach was to determine the optimal stimulation parameters to control spontaneous seizures in a genetic model of absence epilepsy in the rat. In this model, the optimal parameters of single substantia nigra pars reticulata (SNr) stimulation were determined as bilateral, bipolar, monophasic, 60 Hz frequency and 60 µs pulse width. When these parameters were used for repeated stimulations, no long-term suppression and even increase of the number of seizures was observed. A delay of at least 60 sec was necessary between stimulations to be fully effective. Although single high-frequency stimulation of the SNr can be used to suppress ongoing seizures, repeated stimulation are ineffective and could even aggravate seizures, thus supporting the need of closed-loop stimulation procedures to chronically suppress seizures in therapeutical applications. Such an adaptative device would be effective only when detectable changes heralds the seizure onset. In a genetic model of absence epilepsy such changes in the EEG-coherence between the left and right SNr could be identified. Such changes might be used as an hallmark for adaptative procedures like triggered single stimulation to avoid the occurrence of the presumed seizures. To date it remains unknown, if such changes in coherence between left and right SNr, are specific to the model of GAERS and if such changes occur also in other animal models or humans with different epileptic syndromes. Accumulating evidences support that epilepsy is not a pathology restricted to the cortex as a seizure generator, but that subcortical structures are also involved, which might open new therapeutic options for patients who are pharmacoresistant and no candidates for a resective surgical treatment.Près de 30% des patients qui souffrent d´une épilepsie sont résistants aux traitements pharmacologiques et seuls 30% de ces patients peuvent bénéficier d'une alternative thérapeutique par résection chirurgicale. La recherche de cibles et stratégies thérapeutiques innovantes constitue un enjeu majeur pour la prise en charge de ces patients. De nombreuses études expérimentales chez l'animal indiquent que les ganglions de la base, et en particulier la substance noire, exercent un contrôle sur la survenue des crises d'épilepsie. Des arguments cliniques, obtenus par électrophysiologie ou imagerie médicale, sont également en faveur de la mise en jeu des ganglions de la base dans certains syndromes épileptiques. Chez des patients souffrant d'épilepsie focale, l'influence de la propagation des crises au travers des ganglions de la base a été examinée en rapport avec le taux de généralisation secondaire. Chez ces patients l'activation des ganglions de la base semble associée à une influence inhibitrice sur la propagation des crises lorsque celles-ci envahissent le lobe frontal. L'exploration de ces mécanismes inhibiteurs des crises est susceptible d'ouvrir de nouvelles perspectives thérapeutiques comme celle portant sur la stimulation intracérébrale profonde. Les premières études de cas explorant les effets de la stimulation intracérébrale des ganglions de la base chez quelques patients ont permis d'obtenir des résultats encourageants chez certains d'entre eux. Cependant de nombreuses études précliniques devraient permettre de préciser les paramètres de stimulation à appliquer. Une approche expérimentale chez l'animal nous a permis de déterminer les paramètres optimaux à appliquer pour controler la survenue de crises spontanées dans un modèle d'épilepsie-absence chez le rat. Dans ce modèle les paramètres optimaux à appliquer à la substance noire réticulée consistent en des stimulations bilatérales, bipolaires, monophasiques, de 60 Hz en fréquence et de 60 µs en largeur d'impulsion. Appliqués de façon répétée, ces paramètres ne permettent cependant pas de supprimer durablement la survenue des crises et ont même tendance à augmenter le nombre de crises enregistrées. Un délais d'au moins 60 seconde entre l'application de deux stimulations consécutives est à respecter pour interrompre les crises. Dans nos conditions, bien qu'une stimulation haute-fréquence de la substance noire réticulée appliquée de façon aigue puisse interrompre une crise en cours, des stimulations répétées semblent inefficaces. Ceci est en faveur du développement en cours, dans de nombreux laboratoire à travers le monde, de procédures de stimulation des crises asservie à leur détection afin de les supprimer de façon chronique dans le cadre d'applications thérapeutiques. De tels systèmes, dits « adaptatifs », seront particulièrement pertinents s'ils sont couplés à des modifications détectables, signalant l'arrivée d'une crise. Dans le modèle d'épilepsie-absence chez le rat, de telles modifications ont été identifiées au niveau de la cohérence entre signaux électroencéphalographiques issus des deux substances substances noires réticulées. Ces modifications pourraient etre utilisées comme signature spécifique de l'imminence d'une crise dans le couplage de la stimulation à la détection des crises. Toutefois, rien ne permet de dire si ces modifications sont spécifiques du modèle etudié ou encore si de telles modifications existent dans certains syndromes épileptiques en clinique. De nombreux arguments existent pour dire que l'épilepsie n'est pas une pathologie restreinte au seul cortex en tant que circuit générateur de crises, mais implique également des structures sous-corticales susceptibles d'exercer un contrôle à distance sur les circuits générateurs de crises. Cette conception de l'épilepsie permet d'envisager le développement de nouvelles stratégies thérapeutiques pour les patients pharmaco-résistants et qui ne peuvent pas bénéficier d'une intervention chirurgicale
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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