1,721,026 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
Electromyographic analysis of core training exercises using Bosu® and Flyboard® tools
No full textPurpose:
Core stability and strength exercises are commonly included in different training programs in order to improve performance, prevent injuries and enhance functional rehabilitation. Previous researches highlighted the importance of these components to increase neuromuscular control and trunk strength in sport, fitness and medical fields, and several tools have been suggested. In particular, unstable surfaces (like Bosu® and Flyboard®) have been investigated in order to analyse core musculature during specific exercises. Even if previous studies suggested how to train those muscles in different conditions, the role of unstable surfaces is still debate. The aim of this study is to investigate the activation of abdominal and lumbar muscles during trunk movements executed with specific tools and body positions.
Methods:
Ten healthy and trained people volunteered for the study (8 male and 2 female, mean age 27,8 years). They performed 4 exercises using Bosu® and Flyboard® : trunk flexion (supine position on the tools - FLEX), trunk extension (prone position on the tools - EXT), sagittal body sway (vertical position on the tools – SAG) and frontal body sway (vertical position on the tools - FRONT). Each movement was executed by holding static muscles contraction at specific body position in order to highlight muscles activation. Muscle activity was recorded using electromyography (EMG) for rectus abdominis (RA), obliquus externus (OE) and lumbar erector spinae (ES) in right (R) and left (L) side of the body. Data were analysed in order to compare different surfaces (Bosu® and Flyboard®) and to quantify the role of each muscle.
Results:
Muscle activity changed in relation to specific tool and body position. In particular, FLEX evidenced higher values for RA using Flyboard® and for OE using Bosu® in both sides, even if the differences between two surfaces were not significant (p>0.05). EXT highlighted similar EMG activity for ES R and ES L in both tools (p>0.05).
FRONT global muscle activity is significantly superior using Flyboard® compared to Bosu ® (p<0.05). In particular, OE and ES for R and L side showed higher values in relation to sway direction (p<0.05).
SAG evidenced increased muscles activity for RA and OE during posterior sway and for ES during anterior sway, (p<0.01) even if no differences were found between two tools (p>0.05).
Conclusions:
Bosu® and Flyboard® increase muscle activity in a similar way during trunk flexion and extension movements. Although the differences were not significant, Bosu® and Flyboard® seem to mainly improve OE and RA activation, respectively. The level of instability and tool’s shape could determine these results. Body sway movements in frontal plane elicit higher muscle activity using Flyboard®, while no differences between surfaces emerge in sagittal plane. The stabilizing role of core musculature is highlighted during anterior and posterior sway, where front and back muscles are differently involved in lumbo-pelvic control. Consequently, isometric exercises using Bosu® and Flyboard® can effectively challenge the core region.
Reference:
Imai A., Kaneoka K., Okubo Y., Shiina I., Tatsumura M., Izumi S., Shiraki H., “Trunk Muscle Activity During Lumbar Stabilization Exercises on Both a Stable and Unstable Surface”, J Orthop Sports Phys Ther 2010 Jun ; 40(6):369-75
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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