Letter knowledge in parent–child conversations

Learning about letters is an important component of emergent literacy. We explored the possibility that parent speech provides information about letters, and also that children’s speech reflects their own letter knowledge. By studying conversations transcribed in CHILDES (MacWhinney, 2000) between parents and children aged one to five, we found that alphabetic order influenced use of individual letters and letter sequences. The frequency of letters in children’s books influenced parent utterances throughout the age range studied, but children’s utterances only after age two. Conversations emphasized some literacy-relevant features of letters, such as their shapes and association with words, but not letters’ sounds. Describing these patterns and how they change over the preschool years offers important insight into the home literacy environment.     

Robust regulation for a 3-DOF helicopter via sliding-mode observation and identification

This paper tackles the problem of robust output regulation for a 3-DOF helicopter. The considered system is subjected to model uncertainties and external perturbations. A sliding mode observer is used to estimate the state vector in finite time and identify the uncertainties and perturbations using the information of the equivalent output injection. Based on these estimations a robust regulation controller is designed. Experimental results show the feasibility of this approach.     

Studying mathematics problem-solving classrooms. A comparison between the discourse of in-service teachers and student teachers

In the article we compare the approaches of 3 in-service teachers and 3 student teachers when they tried to solve a verbal arithmetic problem in the classroom. Each interaction was studied using a System of Analysis that takes into account the cognitive processes involved in the solution of a mathematic problem and describes the interaction at different levels showing what is done and to what degree teachers and/or pupils are responsible for what is done. The results of the study suggest that both groups of teachers are different in how they direct the student’s attention toward the essential aspects implied in the resolution of word problem. On the one hand, the in-service teachers guaranteed students’ understanding of the problem before dealing with the solution, while students teachers only did so when pupils committed errors. On the other hand, the in-service teachers allowed a high level of student participation, while student teachers took a more prominent role so children’s participation was lower.     

Cómo mejorar la comprensión de textos en el aula

¿Qué ocurre cuando un niño comprende o no comprende? ¿Cómo se explica psicológicamente el proceso de comprensión de un texto? Después de aportar una base a ese nivel, el autor construye sobre ella en este artículo un programa de instrucción para mejorar las habilidades de comprensión y un método de evaluación de esas habilidades.     

Reading together in the classroom. A study of the difference between teacher and student interactions and the requirements of the Ministry of Education in Chile / Lectura conjunta en el aula. Un estudio sobre la distancia entre la interacción profesores alumnos y las prescripciones del Ministerio de Educación Chileno

Abstract

In this article we describe the reading comprehension teaching practices of three Chilean teachers, to contrast them with the proposed guidelines from the Chilean Ministry of Education. To do this, we have analysed what contexts of interaction were created in the classroom and which reading processes were promoted by the questions the students were asked. The results show how the teachers’ practices were closer to the ministerial guidelines when they were asked to create specific contexts of interaction, but deviated from these guidelines when the objective was to promote a reflective and critical understanding of the texts.     

In/formal sex education: learning gay identity in cultural and educational contexts in Mexico

This paper addresses how educational and cultural contexts incorporate lessons around sexuality, particularly sexual and gender identity, and how these contexts impact on identity construction of gay men in Mexico City. We analyse the experiences of 15 gay men reported through semi-structured in-depth interviews and how they incorporate sexuality through socialisation with primary social institutions in Mexico's contemporary educational political context. The sample was divided into three generations, and was selected through maximum variability. Results show that men incorporate negative meanings around same-sex sexuality, and themselves from institutions such as school and family. Men are able to deconstruct these meanings through interactions with educational tools such as the Internet and interactions with gay friends. These results are discussed using post-structuralist perspectives to understand how identity is fluid and changing constantly, as well as the need to incorporate stigma-free curricular content in educational contexts.     

Adaptive SMC based on the dynamic containment of the sliding variable

Conventional Sliding Mode Controllers (SMCs) exhibit a robust performance against matched bounded uncertainties and disturbances by containing them under a fixed controller’s effort. Consequently, the controller is commonly found excessive, leading to chattering and straining the actuator. As a solution, the variable-gain SMCs adapt to the instantaneous system requirements, thus attenuating the aforesaid effects and keeping the SMC’s benefits. However, the reported adaptive laws underlying such behavior commonly require arbitrary design considerations and do not consider practical implementation. Unlikely, in this work, a hysteresis-based adaptability law to drive the sliding variable to a boundary layer around zero is proposed. The sliding boundary—hysteresis’ width—will consistently “bounce” over the sliding variable, trying to shrink against it while preserving the sliding mode. This behavior finds its steady-state once the sliding variable and the sliding boundary’s dynamics are synchronized, with no need of subjective or arbitrary adjustments. The close-loop tuning can be derived from the system’s parameters alone, and its steady-state performance can be quantitatively predicted. Furthermore, a method to adjust the sliding surface parameters according to the system’s desired behavior is provided, all in a closed, analytical way. Finally, the physical actuator limits are taken into account and never exceeded, and the discrete nature of the devices normally used for SMC implementation is incorporated throughout. Two examples are studied to portray the proposal’s advantages.