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The effect of surround contact force on vibrotactile perception thresholds at the big toe
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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
Effect of frequency and contact location on vibrotactile perception thresholds at the foot
No full textSpatial summation of vibrotactile sensations at the foot
Full text linkThresholds for the perception of vibration on the hand reduce with increasing area of excitation when the thresholds are mediated by the Pacinian channel (a phenomenon known as spatial summation) but thresholds are generally independent of the area of excitation when they are mediated by non-Pacinian channels. The effect of the area of excitation on vibrotactile thresholds at the sole of the foot has not been thoroughly investigated. In the study reported in this paper, thresholds for the perception of 20Hz vibration and 160Hz vibration were determined on the foot (at the big toe (hallux), the medial (inside) ball, the lateral (outside) ball, and the heel) and on the hand (at the thenar eminence and at the fingertip) in 12 male subjects using four probe diameters: 1mm (0.19cm(2) excitation area), 3mm (0.38cm(2)), 6mm (0.78mm(2)) and 10mm (1.53cm(2)) with a 2mm gap between the vibrating probe and a fixed surround. On both the hand and the foot, thresholds for the perception of 160Hz vibration decreased as the probe diameter increased. There was no overall consistent change in thresholds for the perception of 20Hz vibration. Thresholds for the perception of 160Hz vibration were lowest at the fingertip and highest at the big toe. Thresholds for 20Hz vibration were also lowest at the fingertip. It is concluded that on the sole of the foot there is evidence of spatial summation in the perception of 160Hz vibration, mediated by the Pacinian channel, but not in the perception of 20Hz vibration, mediated by a non-Pacinian channel. The findings show that vibrotactile thresholds at the foot obtained with different areas of excitation, or an unknown area of excitation, should not be compared. It is concluded that there is a need to standardise methods of measuring the vibrotactile thresholds at the foot that are obtained for clinical applications
Effect of contact area on thresholds for the perception of 160 Hz vibration at the big toe
No full textVariations 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
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