Análisis de la satisfacción del alumno con la docencia recibida: un estudio con modelos jerárquicos lineales

Este artículo muestra que cuando se quiere conocer el grado de satisfacción del alumno con la docencia recibida, es aconsejable introducir en su análisis y estudio componentes contextuales. Los resultados obtenidos sugieren la necesidad de considerar los modelos jerárquicos lineales como alternativa metodológica al análisis de varianza tradicional, por su mejor adaptación a las estructuras de datos estudiados, agrupados o anidados en niveles o jerarquías

Monitoring water-soil dynamics and tree survival using soil sensors under a big data approach

ArticleThe high importance of green urban planning to ensure access to green areas requires modern and multi-source decision-support tools. The integration of remote sensing data and sensor developments can contribute to the improvement of decision-making in urban forestry. This study proposes a novel big data-based methodology that combines real-time information from soil sensors and climate data to monitor the establishment of a new urban forest in semi-arid conditions. Water-soil dynamics and their implication in tree survival were analyzed considering the application of di erent treatment restoration techniques oriented to facilitate the recovery of tree and shrub vegetation in the degraded area. The synchronized data-capturing scheme made it possible to evaluate hourly, daily, and seasonal changes in soil-water dynamics. The spatial variation of soil-water dynamics was captured by the sensors and it highly contributed to the explanation of the observed ground measurements on tree survival. The methodology showed how the e ciency of treatments varied depending on species selection and across the experimental design. The use of retainers for improving soil moisture content and adjusting tree-watering needs was, on average, the most successful restoration technique. The results and the applied calibration of the sensor technology highlighted the random behavior of water-soil dynamics despite the small-scale scope of the experiment. The results showed the potential of this methodology to assess watering needs and adjust watering resources to the vegetation status using real-time atmospheric and soil datainfo:eu-repo/semantics/publishedVersio

Numerical evaluation of the Green's functions for arbitrarily shaped cylindrical enclosures and their optimization by a new spatial images method

IIn this paper, a spatial image technique is used to efficiently calculate the mixed potential Green’s functions associated with electric sources, when they are placed inside arbitrarily shaped cylindrical cavities. The technique is based on placing electric dipole images and charges outside the cavity region. Their strength and orientation are thencalculated by imposing the appropriate boundary conditions for the fields at discrete points on the metallic wall. A method for the assessment of the potentials accuracy is proposed, and several optimization techniques are presented. Three cavities are analyzed to demonstrate the usefulness of the techniques. The cutoff frequencies and potentials patterns are compared to those obtained by a standard finite elements technique, showing excellent agreement. Finally, a band-pass filter based on coupled lines is analyzed, demonstrating the practical value of the technique.This work has been developed with support from the Spanish National Project (CICYT) with reference TEC2004-04313-C02-02/TCM, and the Regional Seneca Project with reference 02972/PI/0

Very large stochastic resonance gains in finite sets of interacting identical subsystems driven by subthreshold rectangular pulses

We study the phenomenon of nonlinear stochastic resonance (SR) in a complex noisy system formed by a finite number of interacting subunits driven by rectangular pulsed time periodic forces. We find that very large SR gains are obtained for subthreshold driving forces with frequencies much larger than the values observed in simpler one-dimensional systems. These effects are explained using simple considerations.Comment: 4 pages, 5 figures. to appear in Phys. Rev.

Fraude fiscal e IVA en España: incidencia en un modelo de equilibrio general.

El objetivo del trabajo es cuantificar y analizar los efectos que podrían derivarse de la reducción del fraude fiscal en España. Como herramienta de análisis se emplea un modelo de equilibrio general aplicado que incorpora diferentes escenarios de mejora en el cumplimiento fiscal y permite obtener las repercusiones, tanto para los diferentes sectores de actividad económica, como para los hogares. Para calcular las magnitudes de todos estos cambios, se utilizan diferentes escenarios. Implementando una regla de neutralidad recaudatoria, la simulación de estas mejoras en el cumplimiento fiscal y en la recaudación se logra aproximando los tipos efectivos reales a los tipos nominales del Impuesto sobre el Valor Anadido (IVA) y un descenso equivalente en los tipos efectivos de las cotizaciones sociales. También se considera un escenario Lumpsum y otro sin neutralidad recaudatoria. Los resultados del análisis de la reducción de la evasión e incidencia impositiva diferencial muestran que podría provocar efectos positivos en variables macroeconómicas relevantes. Así, con neutralidad recaudatoria, cuando se reduce la evasión en los sectores fraudulentos, por cada 1,4 puntos porcentuales que aumenten los tipos efectivos del IVA, el PIB crece 1,33%, el empleo aumenta 1,57%, los salarios reales y la rentas de capital suben en 0,76% y 0,06%, respectivamente, la recaudación aumentaría en torno a un 20%, y también se produce una mejora del bienestar del país del 0,48%. Además se infiere la conveniencia de plantear una estrategia de inspección fiscal intersectorialmente diferenciada, focalizándola en determinados sectores.Fraude fiscal, Impuesto sobre el Valor Anadido, Modelos de equilibrio General aplicado.

Synthesis and reactivity of new mixed dicyclopentadienyl Group 4 metal complexes with the doubly bridged bis(dimethylsilanediyl)-cyclopentadiene-(η5-cyclopentadienyl) ligand

The monocyclopentadienyl titanium complex [Ti{(C5H4)(SiMe2)2(η5-C5H3)} Cl3] 3 and the dichloro mixed dicyclopentadienyl Group 4 metal complexes [M(η5-C5R5){(C5H4)(SiMe2)2(η5-C5H3)} Cl2] (R=H; M=Ti 4, Zr 5, Hf 6; R=Me; M=Ti 7) containing the doubly bridged bis(dimethylsilanediyl)-cyclopentadiene-(η5-cyclopentadienyl) ligand were prepared in high yields by reaction of the monolithium salt Li[(C5H4)(SiMe2)2(C5H3)] 2 with equimolar amounts of TiCl4 or the monocyclopentadienyl complexes [Cp′MCl3], respectively. Reactions of the chloro complexes with various alkylating agents afforded the chloroalkyl [M(η5-C5H5){(C5H4)(SiMe2)2(η5-C5H3)}ClR] (M=Ti; R=Me 8, Et 9; M=Zr, R=Me 10, Et 11, CH2Ph 12; M=Hf, R=CH2Ph 13) and dialkyl [M(η5-C5R5){(C5H4)(SiMe2)2(η5-C5H3)}Me2] (M=Ti; R=H 14, Me 15; M=Zr; R=H 16, compounds. Formation of the heterodinuclear complex [Zr(η5-C5H5)Cl2(η5-C5H3)(SiMe2)2(η5-C5H3)Ti(NMe2)3] 17 with amine elimination was observed by 1H-NMR spectroscopy when complex 5 was reacted with Ti(NMe2)4. The catalytic activity of compounds 3–5 for ethylene polymerization has been studied using MAO as cocatalyst

Theory of frequency and phase synchronization in a rocked bistable stochastic system

We investigate the role of noise in the phenomenon of stochastic synchronization of switching events in a rocked, overdamped bistable potential driven by white Gaussian noise, the archetype description of Stochastic Resonance. We present a new approach to the stochastic counting process of noise-induced switching events: starting from the Markovian dynamics of the nonstationary, continuous particle dynamics one finds upon contraction onto two states a non-Markovian renewal dynamics. The output frequency is determined as the velocity of the underlying discrete phase dynamics. The phenomenon of noise-assisted phase synchronization is investigated in terms of an effective, instantaneous phase diffusion. The theory is applied to rectangular-shaped rocking signals versus increasing input-noise strengths. Precise numerical simulations corroborate very favorably our analytical results. The novel theoretical findings are also compared with prior findings.Comment: 14 pages, 4 figure

Minecraft and machinima in action: development of creativity in the classroom

Numerous studies show the positive effects of introducing video games into learning contexts. These instruments help develop 21st century skills, such as creativity, from a dual perspective: i) the students? perspective, since they develop skills and competencies that allow them to find innovative solutions to the challenges posed by games, and to become digital culture producers; and ii) education professionals? perspective, to use these instruments at schools and thereby change the way students learn. Using a sample of 85 first-year secondary school students, this study aims to provide empirical evidence about the development of creativity through the introduction of video games in the classroom. To do this, an eight-week pedagogical workshop was developed, in which the Minecraft video game was introduced in the subject of Technology. To assess the results of the workshop, the participants' creativity was analysed using a pre-test/post-test design through the CREA Test, as well as the evaluation of the students? machinima productions by their teachers. Results show a significant increase in creativity and high scores for machinima productions, highlighting the opportunity to introduce these tools in classrooms in order to develop innovative educational contexts where creative processes and products are the protagonists

Nonlinear Stochastic Resonance with subthreshold rectangular pulses

We analyze the phenomenon of nonlinear stochastic resonance (SR) in noisy bistable systems driven by pulsed time periodic forces. The driving force contains, within each period, two pulses of equal constant amplitude and duration but opposite signs. Each pulse starts every half-period and its duration is varied. For subthreshold amplitudes, we study the dependence of the output signal-to-noise ratio (SNR) and the SR gain on the noise strength and the relative duration of the pulses. We find that the SR gains can reach values larger than unity, with maximum values showing a nonmonotonic dependence on the duration of the pulses.Comment: 7 pages, 2 figure