Reliability of EMG normalisation methods for upper-limb muscles

Abstract

The study investigated different electromyographic (EMG) normalisation methods for upper-limb muscles. This assessment aimed at comparing the EMG amplitude and the reliability of EMG values obtained with each method. Eighteen male tennis players completed isometric maximal voluntary contractions and dynamic strength exercises (push-ups and chin-ups) on three separate test sessions over at least 7 days. Surface EMG activity of nine upper body muscles was recorded. For each muscle, an analysis of variance for repeated measures was used to compare maximal EMG amplitudes between test conditions. The intra-class correlation coefficient, the coefficient of variation and the standard error of measurement were calculated to determine the EMG reliability of each condition. On the basis of a compromise between maximal EMG amplitude and high reliability, the chin-ups appeared to be the optimal normalisation method for M. latissimus dorsi, M. posterior deltoid, M. biceps brachii, M. flexor carpi radialis and M. extensor carpi radialis. The push-ups seemed relevant to normalise M. anterior deltoid and M. triceps brachii activity, while isometric maximal voluntary contraction remained the most appropriate method for M. pectoralis major and M. middle deltoid. Thus, original methods are proposed to normalise EMG signal of upper-limb muscles.     

Student gender stereotypes: contrasting the perceived maleness and femaleness of mathematics and language

The purpose of this study was to evaluate the gender stereotypes endorsed by elementary and high school students regarding mathematics and language. We developed a questionnaire allowing students to rate mathematics and language as either male or female domains and administered it to a sample of 984 elementary and high school French‐speaking Canadian students (Grades 6, 8, and 10). Results showed that, with the exception of Grade 6 boys, students did not believe that mathematics was a male domain, or even conceived of mathematics as a predominantly female domain, suggesting that the traditional stereotype favouring boys in mathematics might have changed over the past few years. Moreover, language was clearly viewed as a female domain. Overall, our findings suggest that boys seem to be in need of encouragement in school, especially regarding language, where the advantage given to girls is particularly salient.     

Glenohumeral contact force during flat and topspin tennis forehand drives

The primary role of the shoulder joint in tennis forehand drive is at the expense of the loadings undergone by this joint. Nevertheless, few studies investigated glenohumeral (GH) contact forces during forehand drives. The aim of this study was to investigate GH compressive and shearing forces during the flat and topspin forehand drives in advanced tennis players. 3D kinematics of flat and topspin forehand drives of 11 advanced tennis players were recorded. The Delft Shoulder and Elbow musculoskeletal model was implemented to assess the magnitude and orientation of GH contact forces during the forehand drives. The results showed no differences in magnitude and orientation of GH contact forces between the flat and topspin forehand drives. The estimated maximal GH contact force during the forward swing phase was 3573 ± 1383 N, which was on average 1.25 times greater than during the follow-through phase, and 5.8 times greater than during the backswing phase. Regardless the phase of the forehand drive, GH contact forces pointed towards the anterior-superior part of the glenoid therefore standing for shearing forces. Knowledge of GH contact forces during real sport tasks performed at high velocity may improve the understanding of various sport-specific adaptations and causative factors for shoulder problems.     

Discourse-aware rumour stance classification in social media using sequential classifiers

Rumour stance classification, defined as classifying the stance of specific social media posts into one of supporting, denying, querying or commenting on an earlier post, is becoming of increasing interest to researchers. While most previous work has focused on using individual tweets as classifier inputs, here we report on the performance of sequential classifiers that exploit the discourse features inherent in social media interactions or ‘conversational threads’. Testing the effectiveness of four sequential classifiers – Hawkes Processes, Linear-Chain Conditional Random Fields (Linear CRF), Tree-Structured Conditional Random Fields (Tree CRF) and Long Short Term Memory networks (LSTM) – on eight datasets associated with breaking news stories, and looking at different types of local and contextual features, our work sheds new light on the development of accurate stance classifiers. We show that sequential classifiers that exploit the use of discourse properties in social media conversations while using only local features, outperform non-sequential classifiers. Furthermore, we show that LSTM using a reduced set of features can outperform the other sequential classifiers; this performance is consistent across datasets and across types of stances. To conclude, our work also analyses the different features under study, identifying those that best help characterise and distinguish between stances, such as supporting tweets being more likely to be accompanied by evidence than denying tweets. We also set forth a number of directions for future research.     

大龄未婚男性的男男性行为及其对公共安全的意义:基于中国农村性别失衡背景的研究发现

基于2008年安徽省CH市JC区的调查数据,通过与同年龄段已婚男性的对比,对性别失衡背景下中国农村大龄未婚男性的男男性行为发生率及其影响因素进行了分析。结果发现,中国的性别失衡确实会使得农村地区的男男性行为发生率增加;而发生男男性行为的人群中,其无保护性行为也达到了一个较高的比例;同时与已婚男性相比,未婚男性在艾滋病和性病知识方面的掌握情况较差,从而为公共卫生安全带来潜在威胁。论文结尾指出了研究结论的政策启示、研究的局限性和未来改进方向。     

Students’ perceptions of parental and teacher academic involvement: Consequences on achievement goals

The present study examined whether students’ perceptions of two major facets of parental and teacher academic involvement (i.e., academic support and academic monitoring), contribute to the process of students’ achievement goals adoption. French junior high-school students completed two questionnaires assessing first their perceptions of parental and teacher academic involvement, and then their achievement goals three months later. Factorial analyses showed that students differentiated parental academic monitoring from parental academic support, while predominantly perceiving their teacher academic involvement as reflecting monitoring. Multilevel modeling analyses indicated that, as expected, students’ perceptions of parental academic support were positively related to mastery goals while unrelated to performance goals. Also as expected, perceived academic monitoring was associated with performance goals, although the findings revealed an equal contribution of perceived parental and teacher involvement. This new insight about the antecedents of students’ achievement goals emphasizes how important is the role of parental and teacher academic socialization.     

Toddlers Default to Canonical Surface‐to‐Meaning Mapping When Learning Verbs

Previous work has shown that toddlers readily encode each noun in the sentence as a distinct argument of the verb. However, languages allow multiple mappings between form and meaning that do not fit this canonical format. Two experiments examined French 28‐month‐olds' interpretation of right‐dislocated sentences (noun_i‐verb, noun_i) where the presence of clear, language‐specific cues should block such a canonical mapping. Toddlers (N = 96) interpreted novel verbs embedded in these sentences as transitive, disregarding prosodic cues to dislocation (Experiment 1) but correctly interpreted right‐dislocated sentences containing well‐known verbs (Experiment 2). These results suggest that toddlers can integrate multiple cues in ideal conditions, but default to canonical surface‐to‐meaning mapping when extracting structural information about novel verbs in semantically impoverished conditions.     

German Book Publishers’ Barriers to Disruptive Innovations: The Case of E-Book Adoption

To succeed in a period of change, German book publishers need to adopt innovations, e.g., implement e-books into their product portfolio. Yet, in the book industry, the adoption of new technologies is not commonplace: Despite being the second biggest book market worldwide, only 1.2 % of all published books in Germany are available as e-books. This problem leads us to investigate the factors that determine whether publishing companies decide in favor or against entering the e-book market. Based on a standardized survey of more than 240 German publishing houses, barriers to innovation adoption are examined from a micro, meso and macro perspective. Our main findings show that individual characteristics of management and the company’s corporate culture strongly predict adoption. Also, organizational communication seems to be critical. Taking this into account, the key resource to enable innovation seems to be information underlining the necessity of communities of practice.     

On the epistemological features promoted by ‘Philosophy for Children’ and their psychological advantages when incorporated into RE

This article presents the epistemological paradigm in which Philosophy for Children (P4C) is embedded and the personal epistemological positions that are promoted by P4C, in order to address the concern that P4C might induce relativism in pupils. On the basis of theoretical considerations and empirical results, it is shown that P4C does not promote absolutism or relativism, either in its premises or in pupils’ personal epistemology. Rather, this method is related to a socio-constructivist and pragmatic paradigm and it promotes an evaluativist position. The relevance of promoting evaluativism (rather that absolutism or relativism) during RE lessons in pupils is then examined through a psychological perspective. The conclusion is that it is worth integrating P4C in RE because it stimulates an evaluativist perspective that is beneficial in terms of both personal need for meaning and social cohesion.