Análisis de las conceptualizaciones erróneas en conceptos de geometría y sistemas de ecuaciones: un estudio con estudiantes universitarios de primer ingreso

En el presente artículo se reportan los resultados de una investigación que clasifica las conceptualizaciones que tienen estudiantes de primer ingreso universitarios de Costa Rica en temas de geometría y sistemas de ecuaciones mediante el modelo SOLO Taxonómico (propuesto por Biggs & Collis, 1982). Inicialmente los estudiantes se ubican en los primeros niveles de razonamiento en los temas de geometría y en niveles intermedios en sistemas de ecuaciones, al final los estudiantes mostraron mejoría después de un curso introductorio de matemáticas.

Randomised controlled trial of home-based walking programmes at and below current recommended levels of exercise in sedentary adults

Objectives: To determine, using unsupervised walking programmes, the effects of exercise at a level lower than currently recommended to improve cardiovascular risk factors and functional capacity.

Let your feet do the walking: constraints on the stability of bipedal coordination

In this paper we consider whether the behaviour of the neural circuitry that controls lower limb movements in humans is shaped primarily by the spatiotemporal characteristics of bipedal gait patterns, or by selective pressures that are sensitive to considerations of balance and energetics. During the course of normal locomotion, the full dynamics of the neural circuitry are masked by the inertial properties of the limbs. In the present study, participants executed bipedal movements in conditions in which their feet were either unloaded or subject to additional inertial loads. Two patterns of rhythmic coordination were examined. In the in-phase mode, participants were required to flex their ankles and extend their ankles in synchrony. In the out-of-phase mode, the participants flexed one ankle while extending the other and vice versa. The frequency of movement was increased systematically throughout each experimental trial. All participants were able to maintain both the in-phase and the out-of-phase mode of coordination, to the point at which they could no longer increase their frequency of movement. Transitions between the two modes were not observed, and the stability of the out-of-phase and in-phase modes of coordination was equivalent at all movement frequencies. These findings indicate that, in humans, the behaviour of the neural circuitry underlying coordinated movements of the lower limbs is not constrained strongly by the spatiotemporal symmetries of bipedal gait patterns.