Search results for "formal"
showing 10 items of 1654 documents
A systematic concept analysis of mental health promotion
2016
Gestión de dinámicas de grupos en la enseñanza del español como lengua extranjera: una propuesta didáctica
2018
La cantidad de factores que influyen en el desarrollo óptimo del proceso de enseñanza-aprendizaje de una lengua extranjera es numerosa y todos ellos se condicionan y retroalimentan entre sí. En concreto, en este artículo se pone el foco sobre la gestión de dinámicas de grupo y, para ello, se ofrece primero una introducción teórica sobre su relevancia para presentar, a continuación, un ejemplo práctico de sesión que recoge los principios descritos. Esta se ha diseñado para maximizar una sinergia positiva y que se alcance el flujo que permita que el aprendizaje alcance las mayores cuotas posibles. There are a large number of factors that condition the optimal development of the teaching-learn…
Synthesis of phenol–formaldehyde resole resins in the presence of tetraalkylammonium hydroxides as catalysts
2000
Abstract We synthesised phenol–formaldehyde resole resins in the presence of tetraalkylammonium hydroxides as catalysts. The activity of these catalysts was compared with the activity of sodium hydroxide. Gas chromatography, thin layer chromatography, 13 C NMR spectrometry, potentiometric titration and a few simple physicochemical methods were used to estimate the composition of the obtained resins and their properties. It was concluded from these studies that tetraalkylammonium hydroxides are active catalysts and the resins obtained in their presence show some interesting properties.
Estimation of Granger causality through Artificial Neural Networks: applications to physiological systems and chaotic electronic oscillators
2021
One of the most challenging problems in the study of complex dynamical systems is to find the statistical interdependencies among the system components. Granger causality (GC) represents one of the most employed approaches, based on modeling the system dynamics with a linear vector autoregressive (VAR) model and on evaluating the information flow between two processes in terms of prediction error variances. In its most advanced setting, GC analysis is performed through a state-space (SS) representation of the VAR model that allows to compute both conditional and unconditional forms of GC by solving only one regression problem. While this problem is typically solved through Ordinary Least Sq…
Integrable models and degenerate horizons in two-dimensional gravity
1999
We analyse an integrable model of two-dimensional gravity which can be reduced to a pair of Liouville fields in conformal gauge. Its general solution represents a pair of ``mirror'' black holes with the same temperature. The ground state is a degenerate constant dilaton configuration similar to the Nariai solution of the Schwarzschild-de Sitter case. The existence of $\phi=const.$ solutions and their relation with the solution given by the 2D Birkhoff's theorem is then investigated in a more general context. We also point out some interesting features of the semiclassical theory of our model and the similarity with the behaviour of AdS$_2$ black holes.
The initial boundary value problem for free-evolution formulations of General Relativity
2017
We consider the initial boundary value problem for free-evolution formulations of general relativity coupled to a parametrized family of coordinate conditions that includes both the moving puncture and harmonic gauges. We concentrate primarily on boundaries that are geometrically determined by the outermost normal observer to spacelike slices of the foliation. We present high-order-derivative boundary conditions for the gauge, constraint violating and gravitational wave degrees of freedom of the formulation. Second order derivative boundary conditions are presented in terms of the conformal variables used in numerical relativity simulations. Using Kreiss-Agranovich-Metivier theory we demons…
The stereographic coordinate system
2003
Measurement report: Photochemical production and loss rates of formaldehyde and ozone across Europe
2021
Various atmospheric sources and sinks regulate the abundance of tropospheric formaldehyde (HCHO), which is an important trace gas impacting the HOx (≡ HO2 + OH) budget and the concentration of ozone (O3). In this study, we present the formation and destruction terms of ambient HCHO and O3 calculated from in situ observations of various atmospheric trace gases measured at three different sites across Europe during summertime. These include a coastal site in Cyprus, in the scope of the Cyprus Photochemistry Experiment (CYPHEX) in 2014, a mountain site in southern Germany, as part of the Hohenpeißenberg Photochemistry Experiment (HOPE) in 2012, and a forested site in Finland, where measurement…
Hands-On Math and Art Exhibition Promoting Science Attitudes and Educational Plans
2017
The current science, technology, engineering, art, math education (STEAM) approach emphasizes integration of abstract science and mathematical ideas for concrete solutions by art. The main aim was to find out how experience of learning mathematics differed between the contexts of school and an informal Math and Art Exhibition. The study participants (N=256) were 12-13 years old from Finland. Several valid questionnaires and tests were applied (e.g., SRQ-A, RAVEN) in pre- and postdesign showing a good reliability. The results based on General Linear Modeling and Structural Equation Path Modeling underline the motivational effects. The experience of the effectiveness of hands-on learning at s…
Do informal musical activities shape auditory skill development in preschool-age children?
2013
The influence of formal musical training on auditory cognition has been well established. For the majority of children, however, musical experience does not primarily consist of adult-guided training on a musical instrument. Instead, young children mostly engage in everyday musical activities such as singing and musical play. Here, we review recent electrophysiological and behavioral studies carried out in our laboratory and elsewhere which have begun to map how developing auditory skills are shaped by such informal musical activities both at home and in playschool-type settings. Although more research is still needed, the evidence emerging from these studies suggests that, in addition to f…