1,720,985 research outputs found
Knee adduction moment and medial contact force - facts about their correlation during gait
No full textThe external knee adduction moment is considered a surrogate measure for the medial tibiofemoral contact force and is commonly used to quantify the load reducing effect of orthopedic interventions. However, only limited and controversial data exist about the correlation between adduction moment and medial force. The objective of this study was to examine whether the adduction moment is indeed a strong predictor for the medial force by determining their correlation during gait. Instrumented knee implants with telemetric data transmission were used to measure tibiofemoral contact forces in nine subjects. Gait analyses were performed simultaneously to the joint load measurements. Skeletal kinematics, as well as the ground reaction forces and inertial parameters, were used as inputs in an inverse dynamics approach to calculate the external knee adduction moment. Linear regression analysis was used to analyze the correlation between adduction moment and medial force for the whole stance phase and separately for the early and late stance phase. Whereas only moderate correlations between adduction moment and medial force were observed throughout the whole stance phase (R(2)?=?0.56) and during the late stance phase (R(2)?=?0.51), a high correlation was observed at the early stance phase (R(2)?=?0.76). Furthermore, the adduction moment was highly correlated to the medial force ratio throughout the whole stance phase (R(2)?=?0.75). These results suggest that the adduction moment is a surrogate measure, well-suited to predicting the medial force ratio throughout the whole stance phase or medial force during the early stance phase. However, particularly during the late stance phase, moderate correlations and high inter-individual variations revealed that the predictive value of the adduction moment is limited. Further analyses are necessary to examine whether a combination of other kinematic, kinetic or neuromuscular factors may lead to a more reliable prediction of the force magnitud
Modulation of the relationship between external knee adduction moments and medial joint contact forces across subjects and activities
No full textObjective: The external knee adduction moment (EAM) is often considered a surrogate measure for the distribution of loads across the tibio-femoral joint during walking. The purpose of this study was to quantify the relationship between the EAM and directly measured medial tibiofemoral contact forces (Fmed) in a sample of subjects across a spectrum of activities.Methods: The EAM for 9 total knee replacement patients was calculated using inverse dynamic analysis while their telemetric implants provided Fmed for multiple repetitions of 10 activities including walking, stair negotiation, sit-to-stand and squatting. The effects of the factors “subject” and “activity” on the relationships between Fmed and EAM were quantified using mixed-effect regression analyses in terms of the root mean squared error (RMSE) and the slope of the regression.Results: Across subjects and activities a good correlation between peak EAM and Fmed was observed with an overall R² value of 0.88. However, the slope of the linear regressions varied between subjects by up to a factor of 2. At peak EAM and Fmed, the RMSE of the regression across all subjects was 35% body weight (BW), while the maximum error was 127%BW.Conclusion: The relationship between EAM and Fmed is generally good, but varies considerably across subjects and activities. These findings emphasize the limitation in relying solely on the EAM to infer medial joint loading when excessive directed co-contraction of muscles exists, and call for further investigations into the soft tissue related mechanisms that modulate the internal forces at the knee
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
Predicting clinical outcome of fracture fixation - A biomechanical study based on retrospective clinical data
Full text linkBone fracture healing is a complex and multifaceted process. Several factors affect the development of new callus such as fixation type, configuration, fracture characteristics and patient’s related factors. This study aims to deeper understand the influence of fracture fixation on bone healing processes. The thesis was subdivided into three main parts, assessing the objective from different perspectives. Firstly, validation of the mRUST scoring system was conducted, revealing its utility in evaluating fracture healing stages via Intraclass Correlation Coefficients between ratings from multiple clinicians, but also highlighting limitations such as visual impairment and bias due to absolute fracture stability conditions. The second research focused on evaluating callus density and size development and healing progress, correlating findings with finite element model simulations. Results indicate how callus development is influenced by bone type and fixation system, with femur cases producing larger and denser callus than tibia. Furthermore, plate fixations produced more irregular callus than nail or nail+plate treatments. FE simulations supported theories of strain-dependency of fracture healing. However, limitations related to model idealization and lack of data were noted. Finally, joint loading analysis in instrumented total knee replacements revealed linear correlations between resultant joint force, body weight, and knee varus angle. While body weight stood out as primary factor in load transmission, varus angle enhanced correlations if combined with other variables. This proves how a large amount of physiological and mechanical factors influence the load transmission at joint level and consequently at the fracture and fixation level, affecting the new bone callus’ development
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
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