Physical fitness normative values for 6–18-year-old Greek boys and girls,using the empirical distribution and the lambda,mu, and sigma statistical method

The aim of the this study was to establish age- and gender-specific physical fitness normative values and to compare percentiles and Z scores values in a large, nationwide sample of Greek children aged 6–18 years. From March 2014 to May 2014, a total of 424,328 boys and girls aged 6–18 years who attended school in Greece were enrolled. The studied sample was representative, in terms of age–sex distribution and geographical region. Physical fitness tests (i.e. 20?m shuttle run test (SRT), standing long jump, sit and reach, sit-ups, and 10?×?5?m SRT) were performed and used to calculate normative values, using the percentiles of the empirical distributions and the lambda, mu, and sigma statistical method. Normative values were presented as tabulated percentiles for five health-related fitness tests based on a large data set comprising 424,328 test performances. Boys typically scored higher than girls on cardiovascular endurance, muscular strength, muscular endurance, and speed/agility, but lower on flexibility (all p values <0.001). Older boys and girls had better performances than younger ones (p?相似文献   

Contradictions,dialectical oppositions and shifts in teaching mathematics

The study reported in this paper concerns the tensions and conflicts that teachers experience while they enact a new set of reform-oriented curricular materials into their classrooms. Our focus is οn the interactions developed in two groups of teachers in two schools for a period of a school year. We use Activity Theory to study emerging contradictions and we elaborate on the construct of dialectical opposition to understand the nature of these contradictions and their potential for teacher learning. We provide evidence that discussions about contradictions and their dialectical character in the two groups support teachers to engage differently in mathematics teaching and learning and carry potentials for shifts in the practices that evolve in their classrooms. Our study addresses empirically in the context of mathematics teaching the philosophical claim about the role of contradictions as a driving force for any dynamic system.     

Students’ achievement goals,emotion perception ability and affect and performance in the classroom: a multilevel examination

Performance at school is affected not only by students’ achievement goals but also by emotional exchanges among classmates and their teacher. In this study, we investigated relationships between students’ achievement goals and emotion perception ability and class affect and performance. Participants were 949 Greek adolescent students in 49 classes and their Greek language and mathematics teachers. Results from multilevel analyses indicated that students’ mastery-approach and performance-approach goals were positively related to positive affect whereas performance-avoidance goals were negatively related to positive affect. At class-level, relationships between achievement goals and affect were moderated by students’ emotion perception ability. These findings highlight the importance of emotion abilities and their role in motivational processes for class-level outcomes.     

Subspace design of low-rank estimators for higher-order statistics

Higher-order statistics (HOS) are well known for their robustness to additive Gaussian noise and ability to preserve phase. HOS estimates, on the other hand, have been criticized for high complexity and the need for long data in order to maintain small variance. Since rank reduction offers a general principle for reduction of estimator variance and complexity, we consider the problem of designing low-rank estimators for HOS. We propose three methods for choosing the transformation matrix that reduces the mean-square error (MSE) associated with the low-rank HOS estimates. We also demonstrate the advantages of using low-rank third-order moment estimates for blind system estimation. Results indicate that the full rank MSE corresponding to some data length N can be attained by a low-rank estimator corresponding to a length significantly smaller than N.     

Changes in school mathematics knowledge in Greece: a Bernsteinian analysis

The purpose of this paper is to critically examine the changes that took place in school mathematics knowledge for pupils aged six and seven (first grade of Greek elementary school) and its pedagogical approach, which took shape following the reforms of the mathematics curricula in 1982 and 2003. Our analysis is based on Bernstein’s theoretical framework on pedagogic discourse and Dowling’s theoretical framework on textual domains. The results showed that there are differences between the 1982 and 2003 reforms, in terms both of the content of mathematics knowledge, as well as of the forms of pedagogic interaction between the teacher and the pupil.     

Contemporary school knowledge democracy: possible meanings,promising perspectives and necessary prerequisites

ABSTRACT

The basic aim of this paper is to discuss the concept ‘Knowledge Democracy’ (KD) and what it can mean in the school context, its implications on knowledge production and dissemination and on the educational practices. We try to enrich this discussion by presenting action research projects to provide case studies of how thinking about KD can reshape educational practice. We consider that the discussion on KD has to be enriched as the concept seems very promising with good prospects towards school’s democratization. On the other hand, as it is quite new, it can encompass internal contradictions that can cause problems at the level of practice. So, we consider very important any contribution to this discussion not as another theoretical sample of the debate on the ‘politics of knowledge’, but because any improvement at the thinking of the issue can be reflected on school practices. Any challenge to traditional politics of knowledge can lead to a deeper understanding of the world of schooling and to transformations through new discourses and new approaches to teaching and learning in school.     

The transition to secondary school geometry: can there be a “chain of school mathematics”?

Students mainly perceive the transition to secondary school as an opportunity to start their school career anew. Reality often proves them wrong, especially in the case of mathematics. In our paper, we briefly discuss children’s transition to secondary school as both an opportunity and a problem, with reference to the Greek context. In discussions about the transition to secondary school and its effect on the teaching and learning of mathematics, primary and secondary school teachers in Greece often depict school mathematics as a “chain” of concepts and procedures. With this metaphor as our reference point, we discuss how ideologies about the teaching of mathematics are enacted in both school levels. We will base our discussion on the analysis of extracts taken from dialogues in primary and secondary school mathematics classrooms in Greece. In our analysis, we employ a Peircean view of semiotics in an attempt to conceptualize students’ rushed introduction to rigor in justifying mathematical statements in secondary school. These extracts are part of a longitudinal study that aimed, on the one hand, to pinpoint discontinuities and continuities in the teaching of geometry between primary and secondary schools and, on the other, to investigate whether a set of curriculum material that we designed could serve as a link in the teaching of geometry between the two school levels.     

The role of autonomy supportive activities on students’ motivation and beliefs toward out-of-school activities

Physical education in elementary education usually provides children’s first contact with sports. According to the trans-contextual model of motivation, physical education teachers can positively influence children’s beliefs toward and actual leisure time physical activity behavior. The aim of this study was to examine the effect of a dance-based physical education program on motivation regarding physical education lesson participation, as well as leisure time physical activity participation. The sample consisted of 252 pupils attending Grades 5 and 6 of elementary school (M_age?=?10.48 years, SD?=?0.50 years). Participants were randomly assigned into three groups. The first group attended a physical education lesson based on various forms of dance, the second one attended lessons with Greek traditional dances only, and the third group served as active control group that attended the typical curriculum. The intervention lasted six weeks. Before and after the intervention, students completed survey-based measures of motivational climate, motivational regulations in physical education and leisure time, enjoyment, attitudes, perceived behavioral control, subjective norms, and intentions toward leisure time physical activity. In support of the trans-contextual model, results showed that students in the dance intervention programs scored significantly higher in perceptions of motivational climate and beliefs toward leisure time physical activity. The findings of the study suggest that dancing lessons at school can bolster more positive attitudes and beliefs toward physical education and leisure time physical activity.     

Using Laboratory Experiments and Circuit Simulation IT Tools in an Undergraduate Course in Analog Electronics

Laboratory-based courses play a significant role in engineering education. Given the role of electronics in engineering and technology, laboratory experiments and circuit simulation IT tools are used in their teaching in several academic institutions. This paper discusses the characteristics and benefits of both methods. The content and structure of an introductory laboratory course in analog electronics is described. The aim of the course is the better understanding of the basic principles of analog electronic circuits without the need of specific technical and computer skills. The impact of the proposed method on the learning process is investigated. The evaluation of our proposal was based on both quantitative and qualitative data. Interesting conclusions about the teaching of electronics in undergraduate education are finally drawn.     

Teaching Image Formation by Extended Light Sources: The Use of a Model Derived from the History of Science

This research, carried out in Greece on pupils aged 12–16, focuses on the transformation of their representations concerning light emission and image formation by extended light sources. The instructive process was carried out in two stages, each one having a different, distinct target set. During the first stage, the appropriate conflict conditions were created by contrasting the subjects’ predictions with the results of experimental situations inspired by the History of Science, with a view to destabilizing the pupils’ alternative representations. During the second stage, the experimental teaching intervention was carried out; it was based on the geometrical optics model and its parameters were derived from Kepler’s relevant historic experiment. For the duration of this process and within the framework of didactical interactions, an effort was made to reorganize initial limited representations and restructure them at the level of the accepted scientific model. The effectiveness of the intervention was evaluated two weeks later, using experimental tasks which had the same cognitive yet different empirical content with respect to the tasks conducted during the intervention. The results of the study showed that the majority of the subjects accepted the model of geometrical optics, that is, the pupils were able to correctly predict and adequately justify the experimental results based on the principle of punctiform light emission. Educational and research implications are discussed.