Search results for "REF"
showing 10 items of 8690 documents
Determination of mercury at picogram level in natural waters with inductively coupled plasma mass spectrometry by using 3D printed metal scavengers
2019
The determination of ultra-trace concentrations of Hg in natural water samples via preconcentration using 3D printed metal scavenger technique followed by inductively coupled plasma mass spectrometry (ICP-MS) was developed. The determination of Hg in certified reference material ERM-CA615 (groundwater) was performed with high accuracy and precision resulting in recovery of 100 ± 3% and RSD <2.5%, respectively. Selective laser sintering (SLS) 3D printing was used to fabricate the scavengers using a mixture of polyamide-12 powder with thiol-functionalized silica. The preconcentration procedure is based on the adsorption of Hg on the scavenger and followed by elution of the preconcentrated Hg …
Early numeracy in low‐performing young children
2009
The aim of this study was to explore the early numeracy of low‐performing young children. The mean age of the children was six years and four months. The 511 participants belonged to three groups: multi‐language children, children with special educational needs and children with average performance. The results showed that there were significant group differences in early numeracy: the children in the reference group had better relational and counting skills than those with a multi‐language background and those with special educational needs. Some differences were found in counting skills between the children with multi‐language background and those with special educational needs. Finally, …
Polyphony in the classroom: reporting narrative action research reflexively
2010
In this article we will present a reflexive way of producing a narrative analysis on teaching and learning that involves all participants of the pedagogical process. Our theoretical contribution rests on the concept ‘lived pedagogy’, adapted from Max van Manen's term ‘lived experience’. Like van Manen, we start by asking the key question of phenomenological–hermeneutical research: what is the nature of the phenomenon as meaningfully experienced? For us, the phenomenon is the pedagogical relationship; the interaction between the people involved in the pedagogical process. Thus, we will present how lived pedagogy is researched through the narratives told by the teacher‐researcher, the student…
Preparation of polycrystalline TiO2 photocatalysts impregnated with various transition metal ions : characterization and photocatalytic activity for …
2002
A set of polycrystalline TiO2 photocatalysts loaded with various ions of transition metals (Co, Cr, Cu, Fe, Mo, V, and W) were prepared by using the wet impregnation method. The samples were characterized by using some bulk and surface techniques, namely X-ray diffraction, BET specific surface area determination, scanning electron microscopy, point of zero charge determination, and femtosecond pump-probe diffuse reflectance spectroscopy (PP-DRS). The samples were employed as catalysts for 4-nitrophenol photodegradation in aqueous suspension, used as a probe reaction. The characterization results have confirmed the difficulty to find a straightforward correlation between photoactivity and si…
Finding books in the Psychology and Sport Library
2015
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A flexible and reconfigurable 5G networking architecture based on context and content information
2017
The need for massive content delivery is a consolidated trend in mobile communications, and will even increase for next years. Moreover, while 4G maturity and evolution is driven by video contents, next generation (5G) networks will be dominated by heterogeneous data and additional massive diffusion of Internet of Things (IoT). The current network architecture is not sufficient to cope with such traffic, which is heterogeneous in terms of latency and QoS requirements, and variable in space and time. This paper proposes architectural advances to endow the network with the necessary flexibility helping to adapt to these varying traffic needs by providing content and communication services whe…
La cultura organizacional y su impacto en el rendimiento de los equipos de trabajo: el papel mediador del clima y la reflexividad
2017
Desde principios del siglo XX se evidencia un interés creciente por parte de los investigadores en comprender cómo las personas observan, describen e interpretan lo que sucede en su ámbito laboral. La cultura y el clima organizacional, representan dos constructos fundamentales utilizados para describir y analizar el fenómeno organizacional (Schein, 2000). El clima explica lo qué sucede en la organización y la cultura explica el por qué sucede (Schein, 2000; Schneider, 2000). La cultura y el clima organizacional han tenido un desarrollo académico muy distinto proveniente tanto de las diferentes disciplinas que les dieron origen, su forma de conceptualización, así como, la forma en la que los…
From Feynman–Kac formulae to numerical stochastic homogenization in electrical impedance tomography
2016
In this paper, we use the theory of symmetric Dirichlet forms to derive Feynman–Kac formulae for the forward problem of electrical impedance tomography with possibly anisotropic, merely measurable conductivities corresponding to different electrode models on bounded Lipschitz domains. Subsequently, we employ these Feynman–Kac formulae to rigorously justify stochastic homogenization in the case of a stochastic boundary value problem arising from an inverse anomaly detection problem. Motivated by this theoretical result, we prove an estimate for the speed of convergence of the projected mean-square displacement of the underlying process which may serve as the theoretical foundation for the de…
L'Unione Europea in materia di immigrazione asilo e refugio. Una strategia di accoglienza per rispondere alla esigenze dettate dai conflitti del XXI …
2018
La razón por la cual decidí comenzar este proyecto de investigación titulado "La Unión Europea sobre inmigración e integración; la reacción de la Unión ante la crisis de los refugiados y sus implicaciones para la gestión de la inmigración; una estrategia de acogida para responder a las exigencias planteadas por los conflictos del siglo XXI” es que creo que las políticas adoptadas por los gobiernos europeos en materia de asilo y refugio, sean la causa de la mala gestión de los flujos migratorios y de la falta de protección de los refugiados y de los solicitantes de asilo que en los últimos años han llamado insistentemente a las puertas de la Unión Europea en busca de refugio. En los últimos …
1986. Las elecciones generales de 22 de junio de 1986. "El cuarto año triunfal para Felipe González"
2014
El 12 de marzo de 1986 se celebraba el Referéndum OTAN. Semanas después Felipe González adelantaba las elecciones generales al 22 de junio de 1986, cinco meses antes de los cuatro años del fin de la legislatura. Contaba con dos bazas importantes a nivel internacional. La primera era que España había firmado el Acta de Adhesión de España a las Comunidades Europeas -hoy Unión Europea- el 12 de junio de 1985, ingresando el 1 de enero de 1986. Dos meses después, el 12 de marzo de 1986 convocó el referéndum sobre la permanencia de España en la OTAN, en el que el Sí que defendía el Gobierno socialista ganó con un 52,5% de votos a favor y un 39,85% de votos en contra. Tras el éxito del referéndum,…