Juan Fernández

Objective: The aim of this research was to study the mediation of body dissatisfaction, physical self-concept, and body mass index (BMI) on the relationship between physical activity and self-concept in adolescents. Materials and Methods: A sample of 652 Spanish students between 12 and 17 years participated in a cross-sectional study. Physical self-concept and general self-concept were assessed with the Physical Self-Concept Questionnaire (CAF), body dissatisfaction with the Body Shape Questionnaire (BSQ), and physical activity was estimated with the International Physical Activity Questionnaire (IPAQ-SF). BMI was utilized as a measurement of body composition. Structural equation modeling was used to assess the results. Results: The resulting models showed good fit indexes. Physical activity had a positive and indirect effect on self-concept (β = 0.29, p < 0.01) and direct effects on dissatisfaction (β = -0.26, p < 0.01) and physical self-concept (β = 0.20, p < 0.01). BMI had a direct effect on dissatisfaction (β = 0.31, p < 0.01) and on physical self-concept (β = -0.10, p < 0.01) and an indirect effect on general self-concept (β = -0.24, p < 0.01). However, it was only associated with physical activity in males, playing a mediating role between physical activity and body dissatisfaction. Conclusion: Physical activity can help individuals to achieve a positive self-concept and promote psychological well-being in adolescents through the improvement of physical perceptions and body satisfaction. The importance of BMI, body dissatisfaction, and physical self-concept on the configuration of the self-concept are also emphasized. Educational policymakers and Physical Education teachers should implement strategies to promote physical activity in the schools and provide a Quality Physical Education programs to increase physical activity during adolescence.

We propose a characterization of mathematical experiments in terms of a setup, a process with an outcome, and an interpretation. Using a broad notion of process, this allows us to consider arithmetic calculations and geometric constructions as components of mathematical experiments. Moreover, we argue that mathematical experiments should be considered within a broader context of an experimental research project. Finally, we present a particular case study of the genesis of a geometric construction to illustrate the experimental use of hand drawings and computers in mathematical practice.

The multilinear extension of a cooperative game was introduced by Owen in 1972. In this contribution we study the Lovász extension for cooperative games by using the marginal worth vectors and the dividends. First, we prove a formula for the marginal worth vectors with respect to compatible orderings. Next, we consider the direct market generated by a game. This model of utility function, proposed by Shapley and Shubik in 1969, is the concave biconjugate extension of the game. Then we obtain the following characterization: The utility function of a market game is the Lovász extension of the game if and only if the market game is supermodular. Finally, we present some preliminary problems about the relationship between cooperative games and combinatorial optimization

The question addressed in this paper is whether particular emotional experiences or episodes of an emotion (such as two experiences of happiness) belong to a natural kind. The final answer to this question is that although some, even many, single episodes of an emotion may group into a natural kind, belonging to a natural kind is a highly contextual matter. The proposal relies on two premises. First, a conception of natural kind-hood that follows Boyd’s Homeostatic Property Cluster Theory. Second, a view of emotional episodes that fits with the External Theory of Perception: typical emotional episodes are perceptual experiences of emotional affordances. After pointing out what candidates for emotional homeostatic properties could be like and suggesting some examples of emotional homeostatic mechanisms, the authors conclude that there are property clusters of emotional perceptions stabilized by homeostatic mechanisms. In spite of this, what counts as an emotional natural kind depends on many factors, not all of them natural: world properties, bodily and mental states of the agent, learning mechanisms that help us to satisfactorily navigate in the world, cultural differences that determine our perceptual style, as well as different interests which guide the explanation and prediction of emotional episodes.

The English translation of Jörn Rüsen’s Historik is a major event in the global community of the theory of history. Few contemporary thinkers in this field have been so systematic and comprehensive as Rüsen. This book, rendered as Evidence and Meaning, is the outcome of a whole life devoted to the renewal of German historicism. Rüsen’s contribution mirrors the great debates held in West Germany since the 1960s about the theory of history, discussions that prompted a conjoint reassessment of the old dispute between historicist academia and Marxist or Weberian sociologism, including the consequences of the linguistic turn. Rüsen has opened the German historicist tradition toward spaces of compromise with the Western “scientific” or more generalizing history. Furthermore, Rüsen’s synthetic historicism, with its insistence on praxis, might be taken as a case of convergent evolution between German and American syntheses of historical life and historical knowledge.

This paper presents a method to compute a posteriori probability intervals when the initial conditional information is also given with probability intervals. The right way to make an exact computation is with the associated convex set of probabilities. Probability trees are used to represent these initial conditional convex sets because they greatly save the space required. This paper proposes a simulated annealing algorithm, which uses probability trees to represent the convex sets in order to compute the a posteriori intervals.

The aim of the present study was to assess the impact of past traumatic war experiences on preadolescents in the Gaza Strip, which could be useful for psychological intervention with current and future child victims. Participants were 521 preadolescents from United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) schools, aged 11 and 13 years old. Sections I to IV from Iraqi Version-Arabic of Harvard Trauma Questionnaire was used to assess trauma experiences and Post-Traumatic Stress Disorder (PTSD). The results show that the preadolescents in the Gaza Strip witnessed the destruction of their homes and the murder of family members and friends. A quarter of the individuals assessed either suffered torture or witnessed others undergoing it, including sexual assaults. Almost half of them experienced a lack of food and clean water. The traumatic and torture experiences seriously affected preadolescents’ mental health as 26.29% met criteria for the diagnosis of PTSD. The data analysis revealed two PTSD modalities, with the severity of impact depending on whether social implications were involved. Further research is required to check whether these two modalities fit to PTSD and complex PTSD. Understanding the effects of past wars on preadolescents in Gaza and distinguishing between different PTSD types could enhance comprehension of the impacts of current attacks on child victims. It can also aid in determining the type of intervention needed to minimize the impact on the mental health of Palestinian youth, enhancing their resilience through psychological and social support.