1,721,032 research outputs found
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
Muscle Cooling and Performance: A Review
Full text linkObjectives: Skeletal muscle performance is determined by muscle temperature. This paperpresents a review of the research literature to contribute to a better understanding of thephysiological mechanisms of muscle fatigue and performance in cold exposure and in repetitiveor sustained physical exertion in terms of isometric maximal force production,electromyographic activities, and gait ground reaction forces.Materials and Methods: The PubMed and MEDLINE databases were searched for relevantarticles in English. The titles and abstracts of all identified studies were initially screened bythe first author to determine whether they could be included. Relevant articles were consideredfor full text analysis. The reference lists of the relevant studies were also checked.Results: The review showed that different cooling methods have been used in the researchsettings. Current applications are reported of cold exposure to assess muscle strength throughmaximum voluntary contraction and functional activities, manual work of the upper limbs,gait and balance, fall risks, and mobility of the lower limbs. The review also showed thatneuromuscular functions are impaired at 0° to 25°C of cold water immersion for 10 to 40 minwhere loss of strength and fatigue occurred in the limb muscles. Although some of the findingsin previous studies about isometric force production in cooled muscles and joints arecontroversial, this review found that impeded strength is relatively well-established.Conclusions: Cooling in cold water at certain temperatures can influence our maximum muscleperformance but may not impact daily activities
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
The Fight on the Flights : Emergency evacuations – human physiological performance, leg muscle activity and gait biomechanics during exhaustive stair and slope ascent
Full text linkPhysical exhaustion can constrain stair ascending capacity during emergency evacuation. The overall aim of this research was to explore and compare stair ascending capacities and physiological limitations when using two different modes: 1) self-preferred pace on three different public stairways, and 2) four machine-controlled paces on a stair machine corresponding to different percentages of maximal aerobic capacity (V̇O2max). After the exhaustive stair ascent, gait biomechanics were also studied when walking on an inclined metal walkway in the laboratory. Participants of different ages, genders and body sizes were recruited from social media. The specific objective was to determine, through the combined analysis of oxygen uptake (V̇O2) and electromyography (EMG), how cardiorespiratory capacity and local muscle fatigue (LMF) in the leg constrain the ascending capacity and affect walking gait kinetics and kinematics.The results showed that the average relative maximum oxygen uptake during stair ascent (V̇O2highest) reached 39-41 mL·min-1·kg-1 at the self-preferred pace in the field, and 44-45 mL·min-1·kg-1 at the controlled step rate (SR) corresponding to 90-100% V̇O2max in the laboratory. During ascent at the self-preferred pace, both V̇O2highest and heart rate (HRhighest) reached about 83-95% level of average human capacity reported in literature. During ascent at 90-100% V̇O2max SRs, the V̇O2highest reached about 92-94% of V̇O2max, while HRhighest peaked between 91 and 97% of HRmax. The SR was sustained at 92-95 steps·min-1 at the self-preferred pace on the stairs to complete the ascents in a 13-floor and 31-floor building. The average ascending durations of 4.3 and 3.5 minutes were recorded at an average SR of 109 and 122 steps·min-1 corresponding to 90 and 100% V̇O2max, on the stair machine. A physiological evacuation model was developed based on individual V̇O2max. The model proved to be useful in estimating step rate and vertical displacement, thus it is recommended for calculating the performance as such speed, height during stair ascent evacuation. The EMG amplitudes (AMPs) were different between the self-paced and controlled ascending speeds. During self-preferred ascent, the leg muscle AMPs showed a decreasing trend and the median frequencies (MDFs) were unchanged or slightly decreased indicating reductions of muscle power production and possible fatigue compensation by speed reduction. This allowed recovery to complete the ascents. In contrast, a significant increase of AMPs and decrease of MDFs were observed in the controlled paces evidencing the leg LMF. A muscle activity interpretation squares (MAIS) model was developed by plotting the muscle activity rate change (MARC) percentile points to interpret dynamic muscle activity changes and fatigue over time. At the self-preferred paces, the MARC points in the MAIS reflected recovery from muscle fatigue through power decrease and pace reduction. At the controlled paces, in contrast, the MARC points reflected muscle fatigue. Thus, MARC and MAIS are useful for observing muscle activity changes during repetitive tasks. Constant ascents at maximal intensity (90-100% V̇O2max) resulted in high lactate production and leg LMF due to high demand and insufficient recovery. This forced the subjects to stop within 5-min. The results infer that the combined effect of cardiorespiratory capacity exaggerated by leg LMF constrained stair ascending capacities, durations and vertical distances, thus restricting the V̇O2 uptake from reaching the V̇O2max, while any recovery can extend the tolerance. Finally, when walking up a 10° inclined surface after exhaustive stair ascent, the peak gait ground reaction forces, peak and minimum foot absolute angles, peak foot angular velocity and acceleration all significantly decreased with an increased required coefficient of friction. The altered gait biomechanics on inclines can affect the human locomotion and impede the evacuation process during emergencies
Effects of Cooling on Ankle Muscle Maximum Performances, Gait Ground Reaction Forces and Electromyography (EMG)
Full text linkBackground: Temperature is considered as a significant determinant of skeletal muscle function and also a predisposing factor for muscular mechanical performance. Yet, the effects of local cooling on neuromuscular function and performance during gait remain unexamined.Objectives: To investigate the effects of local cooling on lower leg muscles’ isometric maximal force production, electromyography (EMG) and gait ground reaction force. Methods: Experimental study, within subject design. Sixteen healthy university students, age (mean ± SD) 27.0±2.9 years participated in the study. The local cooling was induced by immersing both lower legs up to knee for 20 min in cold water (10°C) in a climate chamber. Electromyographic (EMG) activities and the ankle dorsi and plantar flexors maximum isometric forces were measured in tibialis anterior and gastrocnemius medialis muscle by using surface electrodes and dynamometer. Ground reaction forces during gait were measured on a walkway with force plate.Results: There was a significantly reduced isometric maximum force in tibialis anterior (TA) muscle (P<.001) after cooling. The mean EMG amplitude of gastrocnemius medialis (GM) muscle was significantly increased after cooling (P<.003). There were no significant changes in ground reaction forces and RCOF in gait trials after 20 min cooling.Conclusion: Neuromuscular performances were partly altered after cooling. Maximum strength loss occurred in dorsi-flexion. Fatigued, over-exerted power loss was observed in EMG during plantar flexion. These muscular changes did not contribute significantly to normal gait ground reaction forces on dry and level surface. These may indicate that 20 min cooling in the cold water at 10°C can influence our maximum muscle performance, but the cooling may not be strong enough to impact our daily general and sub maximal activities.KeywordsPeripheral cooling, Ground reaction force, Required coefficient of friction, Gait, Muscle maximum performance, EMG
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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