1,720,974 research outputs found
Distractor objects affect fingers' angular distances but not fingers' shaping during grasping
No full textThe aim of the present study was to determine whether and how hand shaping was
affected by the presence of a distractor object adjacent to the to-be-grasped
object. Twenty subjects were requested to reach towards and grasp a 'convex' or a
'concave' object in the presence or absence of a distractor object either of the
same or different shape than the target object. Flexion/extension at the
metacarpal-phalangeal (MCP) and proximal interphalangeal joints of all digits,
and abduction angle between digits were measured by resistive sensors embedded in
a glove. The results indicate robust interference effects at the level of reach
duration and the extent of fingers' abduction angles together with changes at the
level of a single joint for the thumb. No distractor effects on individual
fingers' joints except for the MCP of the middle and little fingers were found.
These findings suggest that the presence of distractor object affects hand
shaping in terms of fingers' abduction angles, but not at the level of 'shape
dependent' fingers' angular excursions. Furthermore, they support the importance
of the thumb for the guidance of selective reach-to-grasp movements. We discuss
these results in the context of current theories proposed to explain the object
selection processes underlying the control of hand action
An object for an action, the same object for other actions: Effects on hand shaping
No full textObjects can be grasped in several ways due to their physical properties, the
context surrounding the object, and the goal of the grasping agent. The aim of
the present study was to investigate whether the prior-to-contact grasping
kinematics of the same object vary as a result of different goals of the person
grasping it. Subjects were requested to reach toward and grasp a bottle filled
with water, and then complete one of the following tasks: (1) Grasp it without
performing any subsequent action; (2) Lift and throw it; (3) Pour the water into
a container; (4) Place it accurately on a target area; (5) Pass it to another
person. We measured the angular excursions at both metacarpal-phalangeal (mcp)
and proximal interphalangeal (pip) joints of all digits, and abduction angles of
adjacent digit pairs by means of resistive sensors embedded in a glove. The
results showed that the presence and the nature of the task to be performed
following grasping affect the positioning of the fingers during the reaching
phase. We contend that a one-to-one association between a sensory stimulus and a
motor response does not capture all the aspects involved in grasping. The
theoretical approach within which we frame our discussion considers internal
models of anticipatory control which may provide a suitable explanation of our
results
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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