Prácticas de profesores de secundaria en la planificación de clase

El proceso de planificar, llevar a la práctica y evaluar diseños curriculares ha sido objeto de análisis en la literatura (Mutton, Hagger y Burn, 2011). Sin embargo, se sabe muy poco de las prácticas que tienen los profesores para su planificación de clase (Akyuz, Dixon y Stephan, 2013) y se han utilizado múltiples instrumentos y procedimientos para estudiarla que usualmente requieren gran cantidad de recursos y se centran en el análisis de un número reducido de casos. Dentro del contexto anterior, en este trabajo, presentamos el diseño de un cuestionario, con base en el modelo análisis didáctico (Gómez, 2007), que nos permitió caracterizar las prácticas de planificación de 28 profesores que cursaban un programa de maestría en una universidad colombiana

Mathematics Teachers’ Feedback Responses to Students’ Errors and Unexpected Strategies

A part of students learning in the classroom depends on how the teacher responds to their thinking. The literature has separately addressed teachers’ feedback responses to errors and unexpected strategies that students put into play when solving tasks. We propose a framework to analyze these responses together based on three criteria: the focus of the answers (teacher or student), the type of knowledge (conceptual or procedural) that the teacher puts into play in the teacher-centered answers, and the types of actions (asking and proposing) involved in student-centered responses. We codified and analyzed the feedback responses of a group of mathematics teachers to a questionnaire that inquired about their curricular practices. We found similarities in their reports of responses to students’ errors and unexpected strategies: two-thirds of teachers have a teacher-centered response. For the student-centered answers, the number of responses of the teacher in which he/she proposes activities is three times the number of responses in which he/she asks students questions. Furthermore, responses to unexpected strategies differ from responses to errors because teachers evaluate, correct, and accept those strategies

Mathematics Teachers’ Feedback Responses to Students’ Errors and Unexpected Strategies

A part of students learning in the classroom depends on how the teacher responds to their thinking. The literature has separately addressed teachers’ feedback responses to errors and unexpected strategies that students put into play when solving tasks. We propose a framework to analyze these responses together based on three criteria: the focus of the answers (teacher or student), the type of knowledge (conceptual or procedural) that the teacher puts into play in the teacher-centered answers, and the types of actions (asking and proposing) involved in student-centered responses. We codified and analyzed the feedback responses of a group of mathematics teachers to a questionnaire that inquired about their curricular practices. We found similarities in their reports of responses to students’ errors and unexpected strategies: two-thirds of teachers have a teacher-centered response. For the student-centered answers, the number of responses of the teacher in which he/she proposes activities is three times the number of responses in which he/she asks students questions. Furthermore, responses to unexpected strategies differ from responses to errors because teachers evaluate, correct, and accept those strategies

Airkids una inhalocámara saludable y divertida para los problemas respiratorios de tu pequeño

20 Páginas.​​Estudios resientes han demostrado que los agentes etiológicos así como los agentes ambientales han presentado tasas elevadas en la población infantil con respecto a las enfermedades respiratorias agudas en Bogotá, a partir de esto se han incrementado las tasas de morbilidad y mortalidad para las enfermedades respiratorias en niños menores de 5 años así como la falta de adherencia al tratamiento para la rehabilitación respiratoria, donde varios estudios han demostrado la importancia de la colocación correcta de las inhalo cámaras así como las posturas adecuadas para los niños en el momento del suministro del medicamento. Por tal razón se busca con el proyecto la innovación de un producto existente para que el niño tenga un mejor uso y adherencia al tratamiento y de la misma forma disminuir las tasas de morbilidad presentes en la población infantil para la ciudad de Bogotá

Optimization of polarization rotators spectral response for broadband optical switching applications

La ponencia se presentó en: VIII Reunión Española de Optoelectrónica OPTOEL’13 , celebrado los días 10-12 de Julio de 2013, lugar de celebración Alcalá de Henares (España).In this work, optimized designs of broadband polarization rotators based on cascaded nematic liquid crystal cells are presented. Visible spectral range (400 nm – 700 nm) is considered in the designs. A simple computational optimization approach, with performance comparable with more complex existing procedures, is used. Application of designed achromatic polarization rotators in the implementation of optical switches for wavelength division multiplexing in polymer optical fibers networks is also analyzed.This work has been sponsored by the Spanish CICYT (grant nº.TEC2012-37983-C03-02) and CAM (grant.nº. S2009/ESP-1781).Publicad

Synthesis of Asymmetric Flat-Top Birefringent Interleaver Based on Digital Filter Design and Genetic Algorithm

A flexible and fast synthesis method for designing asymmetric interleavers with flat-top, low dispersion, adjustable isolation, and bandwidths at both outputs is proposed. Interleavers are designed on birefringent technology allowing linear-phase designs. Z-transform properties and digital filter design techniques are used for designing interleavers under a set of specifications. At a second level, a genetic algorithm optimization approach allows improving the interleaver design adjusting the minimum isolation, at both outputs, below -43 dB and the stop bandwidths to specific normalized values of ±0.15 and ±0.3, with zero dispersion at one output. Improvement of the interleaver order and dispersion below ±50 ps/nm at both outputs are also reported.This work was partially supported in part by the Spanish CICYT under Grants TEC2009-14718-C03-03 and TEC2012-37983-C03-02 and in part by CAM under Grant S2009/ESP-1781.Publicad

Broadband 1×2 liquid crystal router with low thermal dependence for polymer optical fiber networks

A 1×2 optical router based on an achromatic liquid crystal polarization rotator has been designed and experimentally tested. The router can work in the spectral range used in step-index polymer optical fiber networks (400-700 nm) with low wavelength and temperature dependences. The theoretical design is fast and simple and has good agreement with experimental results. Experimental crosstalk is lower than -18.68 dB for both outputs, even with thermal variations of 10 °C. Performance improvement with respect to previously reported devices with similar structure has also been analyzed.This paper was supported by the Spanish Economy and Education Ministries through grants (Refs.TEC2012-37983-C03-02 and PRX12/00007).Publicad

Spectral method for fast measurement of twisted nematic liquid crystal cell parameters

We present an experimental approach for the fast measurement of twisted nematic (TN) liquid crystal (LC) cells' parameters. It is based on the spectral measurements of the light transmitted by the system polarizer-reference wave plate-LC cell-analyzer. The cell parameters are obtained by fitting the theoretical model to the experimental data. This method allows determining the rubbing angle, the twist angle and its sense, and the spectral dispersion of the LC cell retardation, simultaneously, with few measurements and without the need of applying voltage or any specific analytical conditions. The method is validated by characterizing two different TN cells with retardations of about 0.91 and 1.85 mum. The birefringence relative error is less than 1.3%.This work was supported in part by the Ministerio de Economía y Competitividad of Spain under Grant TEC2012–37983–C03–02Publicad

Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor

The main aim of this work was to study the influence of the mixed liquor total solids (MLTS) concentration on membrane permeability (K 20) in a submerged anaerobic membrane bioreactor (SAnMBR) pilot plant, which is equipped with industrial hollow-fibre membranes and treats urban wastewater. This pilot plant was operated at 33°C and 70 days of SRT. Two different transmembrane fluxes (13.3 and 10 LMH) were tested with a gas sparging intensity of 0.23 Nm 3 m -2 h -1 (measured as Specific Gas Demand referred to membrane area). A linear dependence of K 20 on MLTS concentration was observed within a range of MLTS concentration from 13 to 32 g L -1 and J 20 of 10 LMH. K 20 was maintained at sustainable values (about 100 LMH bar -1) even at high MLTS concentrations (up to 20 g L -1). In addition, several short-tests were carried out when the membranes were operated at high MLTS concentrations in order to assess the effect of the physical cleaning strategies (relaxation and back-flush) on membrane performance. It was observed that, with the applied gas sparging intensity, the duration of the relaxation stage did not critically affect the membrane performance. On the other hand, the required back-flush frequency was considerably affected by the MLTS concentration. © IWA Publishing 2012.This research work has been supported by the Spanish Research Foundation (CICYT Projects CTM2008-06809-C02-01 and CTM2008-06809-C02-02, and MICINN FPI grant BES-2009-023712) and Generalitat Valenciana (Projects GVA-ACOMP2010/130 and GVA-ACOMP2011/182), which are gratefully acknowledged.Robles Martínez, Á.; Durán Pinzón, F.; Ruano García, MV.; Ribes Bertomeu, J.; Ferrer Polo, J. (2012). Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor. Water Science and Technology. 66(2):377-384. doi:10.2166/wst.2012.196S37738466

Reconfigurable 1 x 2 wavelength selective switch using high birefringence nematic liquid crystals

This paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/AO.51.005960 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.A reconfigurable 1 x 2 wavelength selective switch, based on a Lyot filter and high birefringence nematic liquid crystals, is proposed. Simulations and experimental results of a reconfigurable switch are reported. Insertion losses from 3.4 dB and rejection ratios up to 15 dB are obtained in a two input channel system at 560 and 621 nm. Control voltages of 0 to 3 VRMS are used.This work was partially supported by the Spanish CICYT (grant No. TEC2009-14718-C03-03) and CAM (grant No. S2009/ESP-1781).Publicad