Introducción seminario II sobre educación matemática y diversidad

En este Seminario se intenta dar un paso adelante, abordando varios aspectos que consideramos deben ser tenidos en cuenta por la comunidad de investigadores en Educación Matemática. Al titularlo “Matemáticas y Diversidad” hemos querido recoger investigaciones desde la educación matemática sobre lo social y sobre otros aspectos no limitados al contenido matemático en sí

Wave-group propagation and hydrodynamics in the inner surf and swash zones

This thesis concerns a fundamental study of grouping waves propagating over a dissipative beach slope (1:100) and the dynamics of the associated long waves. This thesis represents an important contribution to the understanding of the group modulation influence on high and low frequency motions during shoreward propagation. Two new experimental sets of bichromatic wave-groups are presented, where an effective wave generation up to second order is successfully achieved. The IBIMS-ICL data set explores the propagation of identical wave groups. The modulation is controlled by the group frequency, fg, which affects the energy transfer to high and low frequency components. The growth of the high frequency (hf) wave skewness increases when fg decreases. This is explained by nonlinear coupling between the primary frequencies, which results in a larger growth of hf components as fg decreases, causing the hf waves to break earlier. The breaking locations are very well described by the wave-height to effective-depth ratio (gamma). Due to the grouping structure, gamma increases with fg. Therefore, a modified Iribarren number is proposed leading to an improvement in reproducing the measured gamma-values. Within the surf zone, the behaviour of the incident long wave also depends on the group modulation. For low fg conditions, the lf wave decays only slightly by transferring energy back to the hf wave components. However, for high fg wave conditions, strong dissipation of low frequency (lf) components occurs, which is explained in terms of lf wave breaking. The DIFFREP-ICL data set investigates the generation and dynamics of longer waves than the wave-group structure induced by differences in the number of wave groups (Rp) within a repetition period. Consequently, an important energy content is measured at the repetition frequency fr. The cross-shore amplitude evolution at fr is partly explained by nonlinear energy transfers from the primary frequencies, and partly by a breakpoint forcing. When Rp increases, the energy transfer to fr reduces. When Rp >= 3, the amplitude of fr suddenly grows at the breakpoint displaying a node-antinode pattern within the surf zone. The observed dominance of the breakpoint forcing over the energy transfers is justified by the combination of steep-slope regime and steep-wave conditions. A new methodology is proposed to identify the amplitude and phase cross-shore evolution of the radiated and reflected components. When energy dissipation of the higher lf components occurs, the swash is dominated by wave motions occurring at fr.Open Acces

La herramienta arrastre en funciones usando Geogebra

Este documento presenta algunos resultados del trabajo realizado con estudiantes de primer año universitario a los que se les pidió que resolvieran problemas abiertos de cálculo usando GeoGebra. Encontramos en el uso de GeoGebra que el arrastre en el trabajo con funciones, es una herramienta útil para los estudiantes a la hora de resolver problemas. Usando el enfoque instrumental hemos identificado algunas herramientas de arrastre, usadas en funciones que son fundamentales para la solución de problemas de cálculo. Presentamos dos casos que ilustran una clasificación de la herramienta arrastre al trabajar con funciones

Evaluación de las actitudes hacia las matemáticas y el rendimiento académico

En este artículo presentamos los resultados de un estudio realizado con 1.220 alumnos peruanos de educación secundaria obligatoria para evaluar sus actitudes hacia las matemáticas y el rendimiento académico. Los alumnos pertenecen a colegios públicos, privados y concertados. Los resultados indican que las actitudes y el rendimiento académico están correlacionados

ESR Spectrum and Magnetic Behavior of Copper(II) Sebacate

The magnetic susceptibility of copper(II) sebacate, measured between 5 and 400 K, confirms the presence of strongly coupled Cu-Cu pairs. The ESR spectrum, obtained with a polycrystalline sample, shows an important rhombic anisotropy and supports a dₓ²-y² ground-state.Publicado on line en 2014.Facultad de Ciencias Exacta

The influence of bandwidth on the energetics of intermediate to deep water laboratory breaking waves

An experimental investigation of two-dimensional dispersively focused laboratory breaking waves is presented. We describe the bandwidth effect on breaking wave energetics, including spectral energy evolution, characteristic group velocity, energy dissipation and its rate, and breaking strength parameter, b. To evaluate the role of bandwidth, three definitions of wave group steepness are adopted where Ss and Sn are bandwidth-dependent and Sp remains constant when bandwidth is changed. Our data show two regimes of spectral energy evolution in breaking wave groups, with both regimes bandwidth-dependent: energy dissipation and gain occur at f > 0.95fp ( fp is the peak frequency) and f < 0.95fp, respectively. The characteristic group velocity, which is used in energy dissipation calculations, increases by up to 7% after wave breaking, being larger for higher bandwidth breaking waves. An unambiguous bandwidth dependence is found between Sp and both the fractional and absolute wave energy dissipation. Wave groups of larger bandwidth break at a lower value of Sp and consequently lose relatively more energy. The energy dissipation rate depends on the breaking duration which itself is bandwidth dependent. Consequently, no clear bandwidth effect is observed in energy dissipation rate when compared with either Sp or Ss. However, there is a systematic bandwidth dependence in the variation of b when parameterised in terms of Sp, with their relationship becoming increasingly nonlinear as bandwidth increases. When parameterised with Ss, b shows a markedly reduced bandwidth dependence. Finally, the numerical breaking onset and relationship between b and Ss in the numerical study of Derakhti & Kirby (J. Fluid Mech., vol. 790, 2016, pp. 553–581) is validated experimentallyNational Science Foundation (grant number OCE-1434866)Royal Society Shooter International Fellowship and a NERC Standard Grant (grant number NE/T000309/1)NERC (grant number NE/T000309/1

Synthesis and characterization of EDTA complexes useful for trace elements supplementation

The synthesis of two heterobimetallic EDTA complexes, MgCu(EDTA).6H2O and ZnCu(EDTA).6H2O, is described. They were characterized by means of vibrational (infrared and Raman) and electronic (reflectance) spectroscopy. Several dissolution tests in 0.1 N HCl and simulated gastric juice were also performed. The results support the potential usefulness of these complexes for copper supplementation in human and veterinary medicine and to the simultaneous reinforcement of Mg(II) and Zn(II) levels.Facultad de Ciencias Exacta