1,720,955 research outputs found
Vascular responses to acute vibration in the fingers of normal subjects
No full textThe aim of this experimental study was to investigate the pathophysiological mechanisms involved in the acute effects of unilateral vibration on the digital circulation of healthy men. In the fingers of both hands of eight male subjects (age 23-47 years) who had never worked with vibrating tools, finger blood flow (FBF) and finger skin temperature (FST) in thermoneutral conditions, and the percentage change of finger systolic pressure (FSP %) after local cooling from 30 to 10 °C were measured. The right hand was exposed for 30 min to sinusoidal vibration with a frequency of 125 Hz and an acceleration of 87.5 m.s.-2 r.m.s. A control condition consisted of exposure to the same static load (10 N) but without vibration. The measures of digital circulation were taken before exposure to vibration and static load and at 0, 30, 60, and 90 min after the end of each exposure. Exposure to static load caused no significant changes in FBF, FST, or FSP% in either the test right or the control left finger. Immediately after vibration, there was a temporary increase in FBF in the vibrated right finger, while the non-vibrated left finger exhibited no vasodilation. In both the vibrated and non-vibrated fingers, FBF and FST significantly reduced during the recovery time. A large intersubject variability was observed for FBF and, to a lesser extent, for FST. In the vibrated right finger the decrease in blood flow was significantly related to cold-induced vasoconstriction in the digital vessels. Such a relation was not observed in the non-vibrated left finger. The results of this investigation suggest that acute vibration can disturb the function of digital vessels through two different and opposite mechanisms. Vibration appears to produce local vasodilation and to trigger a central sympathetic reflex vasoconstriction which can be recorded in the ipsilateral and the contralateral finger to vibration. Both local and central vasoconstrictor mechanisms are likely to be involved in the response to cold observed in the digital vessels of a vibrated finger.</p
Effect of starting temperature on the repeatability of thermotactile thresholds
No full textHand-transmitted vibration has been observed to cause a wide variety of different signs and symptoms of neurological dysfunction. Different test of tactile sensitivity, encompassing sensations of pressure, vibration, pain and temperature have been employed in the quantification of the sensorineural effects of vibration. However, since the results of such tests are dependent on different variables, and different versions of each test are used in different laboratories, the results are rarely reported in a manner allowing a direct comparison of results between studies. This paper reports on an investigation of the repeatability of thermotactile thresholds, as used in the detection of some neurological effects of hand-transmitted vibration. In the test, the temperature of a surface increased or decreased from a fixed reference (i.e. starting) temperature at a rate of 1 °C per second. In a group of 10 healthy male subjects, five measures of both warm and cool thermal thresholds were obtained with each of 5 different starting temperatures on each of 3 different days. The 'neural zone' between the warm and cool thresholds was also calculated. The starting temperature was found to have a significant effect on warm and cool thresholds,and less effect on the width of the neutral zone. It is concluded that the starting temperature should be controlled when determining thermotactile thresholds.</p
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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