1,720,956 research outputs found
Dopaminergic effects on the implicit processing ofdistracter objects in Parkinson’s disease
Full text linkThe aim of the present study was to assess the effects of dopaminergic medication on the
selection-for-action mechanisms in Parkinson’s disease (PD). PD subjects were tested after not having
taken medication for at least 12 h ("Off" state) and then retested 1-2 h after medication ("On" state). A
three-dimensional kinematic system (ELITE, BTS, Italy) was used to record reach-to-grasp
movements to a target object placed at a reaching distance of 30 cm. The target was presented alone or
in the presence of distracter objects, which could be of either the same size (compatible distracter) or a
different size (incompatible distracter). PD subjects in the Off state were significantly more affected
by the presence of the incompatible distracter than in the On state. These results indicate that
dopaminergic medication is of benefit in reducing interference effects when distracter objects evoke
motor programs that differ from the motor program elicited by the target. Results are discussed in light
of the role played by the striatal and mesocortical dopaminergic systems for response selection in basal
ganglia disorders
The effect of unilateral posteroventral pallidotomy on the kinematics of the reach to grasp movement
No full textObjective-to assess postoperative effects of unilateral posteroventral pallidotomy on the organisation of upper limb movement
The reach-to-grasp movement in Parkinson’s disease:response to a simultaneous perturbation of object positionand object size
Full text linkThis study assessed the adaptive response of
the reach-to-grasp movement of 12 Parkinson’s disease
(PD) and 12 control subjects to a simultaneous perturbation
of target object location and size. The main aim was
to test further the reported dysfunction of PD subjects in
the simultaneous activation of movement components.
Participants were required to reach 30 cm to grasp a central
illuminated cylinder of either small (0.7 cm) or large
(8 cm) diameter. For a small percentage of trials
(20/100) a visual perturbation was introduced unexpectedly
at the onset of the reaching action. This consisted of
a shift of illumination from the central cylinder to a cylinder
of differing diameter, which was positioned 20° to
the left (n=10) or to the right (n=10). The subject was required
to grasp the newly illuminated cylinder. For the
Parkinson’s disease subject group, the earliest response
to this ‘double’ perturbation was in the parameter of
peak reaching acceleration, which was on average 50 ms
earlier for ‘double’ perturbed than for non-perturbed trials.
The grasp component response followed more than
500 ms after the earliest transport response. For the control
subjects initial signs of a response to the ‘double’
perturbation were seen almost simultaneously in the
transport parameter of peak arm deceleration, and in the
manipulation parameter of maximum grip aperture, but
these changes were not evident until more than 400 ms
after movement onset. These results indicate that the
basal ganglia can be identified as part of a circuit which
is involved in the integration of parallel neutral pathways,
and which exercise flexibility in the degree to
which these components are ‘coupled’ functionally. With
basal ganglia dysfunction the activation of integration
centres that at first gate the flow of information to the
parallel channels of reach and grasp seems inefficient
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
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
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