1,720,967 research outputs found
Mirror neurons in humans: consisting or confounding evidence?
No full textThe widely known discovery of mirror neurons in macaques shows that premotor and
parietal cortical areas are not only involved in executing one's own movement,
but are also active when observing the action of others. The goal of this essay
is to critically evaluate the substance of functional magnetic resonance imaging
(fMRI) and positron emission tomography (PET) studies whose aim has been to
reveal the presence of a parallel system in humans. An inspection of this
literature suggests that there is relatively weak evidence for the existence of a
circuit with 'mirror' properties in humans, such as that described in monkeys
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
Motor ontology in representing gaze-object relations
No full textEvent-related functional magnetic resonance imaging (fMRI) was used to explore
how the human brain models gaze-object relations. During scanning participants
observed a human model gazing towards or away a target object presented either in
isolation or flanked by a distractor object. In two further conditions the
model's gaze was shifted and subsequently maintained away from the stimulus/i.
These four conditions were implemented within a factorial design in which the
main factors were "type of observed behavior" (gaze vs. gaze-away) and "context"
(target alone vs. target flanked by a distractor). Results revealed that
premotor, parietal and temporal areas, known to sub-serve the understanding of
other people actions, were significantly more activated by the observation of the
model gazing towards rather than away from the stimulus/i. In addition, a
significant interaction indicated that, when the target was presented in
isolation, neural activity within the inferior frontal gyrus, another key area
for action understanding, was influenced by gaze-object relations. Our findings
suggest that this area is important for the establishment of intentional
gaze-object relations and indicate that the presence of a distractor interferes
with the representation of such relations
Neurofunctional modulation of brain regions by the observation of pointing and grasping actions
No full textPrevious neuroimaging research on healthy humans has provided evidence for a
neural system underlying the observation of another person's hand actions.
However, whether the neural processes involved in this capacity are activated by
the observation of other transitive hand actions such as pointing remains
unknown. Therefore, using functional magnetic resonance imaging we investigated
the neural mechanisms underlying the observation of static images representing
the hand of a human model pointing to an object (pointing condition), grasping an
object (grasping condition), or resting in proximity of an object (control
condition). The results indicated that activity within portions of the lateral
occipitotemporal and the somatosensory cortices modulates according to the type
of observed transitive actions. Specifically, these regions were more activated
for the grasping than for the pointing condition. In contrast, the premotor
cortex, a neural marker of action observation, did not show any differential
activity when contrasting the considered experimental conditions. Our findings
may provide novel insights regarding a possible role of extrastriate and
somatosensory brain areas for the perception of distinct types of human
hand-object interactions
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
- …
