La aproximación neuropsicológica a la dislexia evolutiva. I: Maduración cerebral

Resumen

En los últimos años se constata un auge singular de la neuropsicología de las dificultades de aprendizaje, en especial de la neuropsicología de la dislexia evolutiva. En este trabajo se estudia, como posible explicación etiológica de la dislexia evolutiva, el fallo en el desarrollo madurativo cerebral; se revisan y analizan, a efectos de poder ofrecer pronósticos y modos de intervención apropiados, la diferencia entre la hipótesis del retraso y la del déficit en la maduración, así como la alternativa de restitución o sustitución en la recuperación funcional. Se examinan también otros problemas relacionados entre sí con la dislexia y con la neuropsicología del desarrollo, a saber, la base neurofistológica para formación de subgrupos disléxicos, la disfunción de secuenciación oculomotora como etiología de dislexia y, por fin, la luz que la dislexia adquirida aporta a la dislexia evolutiva al relacionar lesiones del lóbulo parietal inferior con el subdesarrollo madurativo de estas mismas zonas cerebrales.     

Grade level, study time, and grade retention and their effects on motivation, self-regulated learning strategies, and mathematics achievement: a structural equation model

The present study complements previous research findings with new data to improve our understanding of the relationship between motivational variables and academic performance in math mediated by self-regulated learning (SRL). A structural equation model with predictor (i.e., grade retention, grade level, and study time), process (i.e., perceived usefulness of SRL strategies, self-efficacy for the use of SRL strategies, and reported use of SRL), and product variables (i.e., academic achievement in mathematics) is proposed. The model was analyzed in two samples of data (calibration and validation samples). The first sample served to fit and respecify the model, and the second one was used to analyze the consistency of the findings of the first sample. A sample of 756 middle school Portuguese students participated in the current study. The results indicate that SRL is positively and significantly related to academic achievement and that the latter is, in turn, powerfully determined by perceived usefulness and self-efficacy, although students’ reported use of SRL strategies decreases from 7th to 9th grades. Self-efficacy and perceived usefulness of SRL strategies were also found to decrease as grade retention increased. These results are discussed with regard to the relevance of self-efficacy and perceived usefulness of SRL strategies in increasing academic achievement.     

The Engagement of Older People in Civil Society Organizations

This article reviews recent international literature on the opportunities and restrictions experienced by older people to act as volunteers in civil society organizations. Our aim was to develop a conceptual framework applicable to the European ageing society. This aim was pursued through a computerized database search focused on studies analyzing the individual, organizational, and/or societal levels. Findings show that senior volunteers are characterized by “younger” age, good health, and a high level of both educational and socioeconomical status. Volunteers are involved mainly in religious organizations as well as in social and personal care, while main barriers are represented especially by ageist practices. The review shows that the debate on this topic has been barely developed in Europe, both from an individual and societal point of view. Therefore, European countries might take advantage from experiences made in other contexts, but the identification of how this can occur requires further and more specific cross-national research.     

Using genetic algorithms to evolve a population of topical queries

Systems for searching the Web based on thematic contexts can be built on top of a conventional search engine and benefit from the huge amount of content as well as from the functionality available through the search engine interface. The quality of the material collected by such systems is highly dependant on the vocabulary used to generate the search queries. In this scenario, selecting good query terms can be seen as an optimization problem where the objective function to be optimized is based on the effectiveness of a query to retrieve relevant material. Some characteristics of this optimization problem are: (1) the high-dimensionality of the search space, where candidate solutions are queries and each term corresponds to a different dimension, (2) the existence of acceptable suboptimal solutions, (3) the possibility of finding multiple solutions, and in many cases (4) the quest for novelty. This article describes optimization techniques based on Genetic Algorithms to evolve “good query terms” in the context of a given topic. The proposed techniques place emphasis on searching for novel material that is related to the search context. We discuss the use of a mutation pool to allow the generation of queries with new terms, study the effect of different mutation rates on the exploration of query-space, and discuss the use of a especially developed fitness function that favors the construction of queries containing novel but related terms.     

Ranking dynamics and volatility

Scientific journals are ordered by their impact factor while countries, institutions or researchers can be ranked by their scientific production, impact or by other simple or composite indicators as in the case of university rankings. In this paper, the theoretical framework proposed in Criado, R., Garcia, E., Pedroche, F. & Romance, M. (2013). A new method for comparing rankings through complex networks: Model and analysis of competitiveness of major European soccer leagues. Chaos, 23, 043114 for football competitions is used as a starting point to define a general index describing the dynamics or its opposite, stability, of rankings. Some characteristics to study rankings, ranking dynamics measures and axioms for such indices are presented. Furthermore, the notion of volatility of elements in rankings is introduced. Our study includes rankings with ties, entrants and leavers. Finally, some worked out examples are shown.     

Differences in strength and speed demands between 4v4 and 8v8 small-sided football games

ABSTRACT

The aims of this study were (i) to characterise the acceleration demands of two different formats of small-sided game (SSG), i.e., 4v4 + goalkeepers (4v4 + GK) and 8v8 + goalkeepers (8v8 + GK); (ii) to analyse the correlation between performance in power-based tests and acceleration-based physical loading during the two different SSG formats and (iii) to analyse the neuromuscular-induced fatigue. Eighteen adult male footballers participated in the study (20.7 ± 1.0 years, 178 ± 5 cm and 71.4 ± 2.1 kg). Baseline measurements were obtained from countermovement jumps, 15 s repeated jumps and 5 and 15 m sprints. A total of 36 min was analysed for each SSG (4v4 + GK: two sets of 3 × 6 min, and 8v8 + GK: 2 × 18 min). Heart rate, blood lactate, perceived exertion and movement pattern (GPS) were analysed. Distances covered by very-high-intensity activities and very-high-speed running were lower in 4v4 + GK than in 8v8 + GK (effect sizes (ES) = ?0.69 ± 0.67 and ?1.04 ± 0.67, respectively; very likely), while accelerations and decelerations were higher in 4v4 + GK than in 8v8 + GK (ES = 1.13–1.52; almost certainly). Blood lactate concentrations were higher (ES = 1.40 ± 0.58; almost certainly) and players perceived themselves to be more tired (ES = 0.80–2.31; almost certainly) after 4v4 + GK than after 8v8 + GK. Sprint ability in 5 and 15 m tests decreased (ES = 0.87 ± 0.58 and 0.89 ± 0.58, respectively; almost certainly) only after 4v4 + GK. This SSG format appeared more demanding in relation to repetitions and fatigue development of muscle power-based actions than 8v8 + GK. It may therefore be logical to use the former type of SSG to target development of power-related football actions.