1,720,966 research outputs found
Neural correlates of motor learning and performance in a virtual ball putting task
No full textLearning to move skillfully requires that the motor system adjusts motor commands based on ongoing performance, until the task is executed satisfactorily. Robots can be used to emulate motor tasks that involve haptic interaction with objects. These studies may provide useful insights on how humans acquire a novel motor skill. Here we address motor skill learning in a 2D ball putting task, by looking at both kinematic and EEG correlates of learning and performance. Participants grasped the handle of a manipulandum and had to hit a virtual ball in order to put it into a target region (hole). The robot was used to render the contact force with the ball during impact. At every trial, with respect to the initial ball position, the hole appeared in one of three different directions and two distances, selected randomly. The experimental protocol included a total of 300 movements. In movement kinematics we looked at the effects of learning and target distance. In EEG signals, we looked at the effect of learning and the effect of success/failure on the ongoing brain activity. Subjects managed to improve their performance through practice, in all directions and at both target distances. Direction did not affect the performance much, but greater target distance induced greater errors. With regards to the EEG activity, we found that (i) practice led to an increased theta synchronization in the frontal areas; (ii) successful trials were preceded by higher theta synchronization, and alpha and beta desynchronization. These results suggest that EEG signals can be used to monitor the learning process and to predict the outcome (success/failure) of individual trials. These findings open possibilities to develop new schemes to promote and facilitate learning, which integrate EEG and robots
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
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
Barley-derived (1.3) beta-D-glucans promotes angiogenesis involving histone H4 acetylation in human endothelial cells and zebrafish under oxidative microenvironment
No full textBackground: Angiogenic response of adult endothelial cells can significantly improve the repair potential of ischemic myocardium; however, it is challenging topromote it in the presence of oxidative stress. We recently demonstrated that increased global histone H4 acetylation promotes angiogenesis under oxidative microenvironment; thus, the identification of novel natural angiomodulators is a desirable achievement. Barley-derived (1.3)beta-D-glucan (β-D-glucan) is a watersoluble
chain of D-glucose polysaccharide with antioxidant properties, but its angiogenic effect is still unknown. We investigated whether the conditioning of adult endothelial cells with β-D-glucan enhances the angiogenic response to oxidative stress involving histone H4 acetylation.
Methods: In vitro, human umbilical vein endothelial cells (HUVECs) chronically exposed to H2O2 (50uM for 24h) were cultured with or without 3% w/v β-D-glucan, then tested for cell viability and tube formation. p-eNOS/eNOS ratio, pAkt/Akt ratio, HIF1-alpha and MnSOD expression, and the level of histone H4 acetylation
were evaluated. In vivo, Tg(kdrl:EGFP)s843Tg transgenic zebrafish embryos were treated for 24h with 3% w/v β-D-glucan under oxidative microenvironment prior angiogenesis assay.
Results: HUVECs treatment with β-D-glucan prevented cell death by 87.41±14% (P≤0.004) and significantly increased tube formation activity by 11±4% under oxidative microenvironment. At the cellular level such effects seem to be mediated by an epigenetic induction of MnSOD expression through significant increase of histone H4 acetylation (+410±34.3%). Finally, similar dose of β-D-glucan was
confirmed to prevent vascular depletion in zebrafish embryos chronically exposed to oxidative microenvironment.
Conclusions: Our study revealed, for the first time, that barley-derived β-Dglucan promotes adult angiogenesis under oxidative microenvironment through increased histone H4 acetylation. These findings uncover a novel and unexpected role for dietary β-D-glucan as a critical epigenetic activator of antioxidant activity
governing adult angiogenic response
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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