2,360 research outputs found

    Contributos da educação intercultural na construção de uma sociedade pluralista e democrática numa perspectiva comparada – Portugal e Espanha

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    No momento que hoje vivemos, a problemática das relações interculturais apresenta-se-nos de uma forma particularmente intensa. O projecto europeu desenvolve-se e aprofunda-se, o fenómeno dos nacionalismos propaga-se por toda a Europa, tornando por demais evidentes todas as idiossincrasias nacionais e multiplicidades culturais. Paralelamente verificamos fenómenos de deslocação de populações em larga escala e particularmente em Portugal e Espanha, tradicionais países de emigração, nestes últimos anos somos confrontados com vagas massivas de imigrantes quer de países africanos e sul-americanos, quer mais recentemente do leste europeu. A imigração na Península Ibérica é presentemente uma realidade inelutável especialmente se considerarmos a quantidade e a diversidade de origens dos imigrantes. A melhoria das condições de vida após os primeiros anos de imigração e os programas de reagrupamento familiar levam a que nos últimos anos o número de crianças imigrantes tenha aumentado quer no sistema educativo português quer no espanhol. Este facto por si só poderá explicar a necessidade crescente de criar espaços na escola para a educação intercultural, uma vez que esta surge como local privilegiado de socialização e aquisição da própria cultura e simultaneamente como forma de interacção comunicante com a cultura do «outro». Neste contexto procuraremos efectuar uma análise da situação em que se encontra a educação intercultural em Espanha e Portugal, enraizando-a na educação para a cidadania, tentando assim encontrar pontos comuns de actuação e simultaneamente aprender com as experiências realizadas em ambos os países, contribuindo para a construção de uma sociedade verdadeiramente multicultural

    Thorpe method applied to planetary boundary layer data

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    Turbulence affects the dynamics of atmospheric processes by enhancing the transport of mass, heat, humidity and pollutants. The global objective of our work is to analyze some direct turbulent descriptors which reflect the mixing processes in the atmospheric boundary layer (ABL). In this paper we present results related to the Thorpe displacements dT , the maximum Thorpe displacement (dT )max and the Thorpe scale LT , the Ozmidov scale and their time evolution in the ABL during a day cycle. A tethered balloon was used to obtain vertical profiles of the atmospheric physical magnitudes up to 1000m. We discuss the vertical and horizontal variability and how different descriptors are related to atmospheric mixing

    An experimental model of mixing processes generated by an array of top-heavy turbulent plumes

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    The mixing process of two fluids of unequal density generated by the evolution of an array of forced turbulent plumes is studied in the laboratory. The corresponding qualitative conclusions and the quantitative results based on measures of the density field and of the height of the fluid layers are described. The partial mixing process is characterized and analyzed, and the conclusions of this analysis are related to the mixing efficiency and the volume of the final mixed layer as functions of the Atwood number, which ranges from 0.010 to 0.134. An exponential fit is used to evaluate the mixing efficiency versus the Atwood showing the role of initial conditions on mixing efficiency variability

    Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale

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    We present a study of the HII regions in the galaxy NGC 6754 from a two pointing mosaic comprising 197,637 individual spectra, using Integral Field Spectrocopy (IFS) recently acquired with the MUSE instrument during its Science Verification program. The data cover the entire galaxy out to ~2 effective radii (re ), sampling its morphological structures with unprecedented spatial resolution for a wide-field IFU. A complete census of the H ii regions limited by the atmospheric seeing conditions was derived, comprising 396 individual ionized sources. This is one of the largest and most complete catalogue of H ii regions with spectroscopic information in a single galaxy. We use this catalogue to derive the radial abundance gradient in this SBb galaxy, finding a negative gradient with a slope consistent with the characteristic value for disk galaxies recently reported. The large number of H ii regions allow us to estimate the typical mixing scale-length (rmix ~0.4 re ), which sets strong constraints on the proposed mechanisms for metal mixing in disk galaxies, like radial movements associated with bars and spiral arms, when comparing with simulations. We found evidence for an azimuthal variation of the oxygen abundance, that may be related with the radial migration. These results illustrate the unique capabilities of MUSE for the study of the enrichment mechanisms in Local Universe galaxies.Comment: 13 pages, 7 Figurs, accepted for publishing in A&

    Detection of Anti-Counterfeiting Markers through Permittivity Maps Using a Micrometer Scale near Field Scanning Microwave Microscope

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    [EN] This paper describes the use of microwave technology to identify anti-counterfeiting markers on banknotes. The proposed method is based on a robust near-field scanning microwave microscope specially developed to measure permittivity maps of heterogeneous paper specimens at the micrometer scale. The equipment has a built-in vector network analyzer to measure the reflection response of a near-field coaxial probe, which makes it a standalone and portable device. A new approach employing the information of a displacement laser and the cavity perturbation technique was used to determine the relationship between the dielectric properties of the specimens and the resonance response of the probe, avoiding the use of distance-following techniques. The accuracy of the dielectric measurements was evaluated through a comparative study with other well-established cavity methods, revealing uncertainties lower than 5%, very similar to the accuracy reported by other more sophisticated setups. The device was employed to determine the dielectric map of a watermark on a 20 EUR banknote. In addition, the penetration capabilities of microwave energy allowed for the detection of the watermark when concealed behind dielectric or metallic layers. This work demonstrates the benefits of this microwave technique as a novel method for identifying anti-counterfeiting features, which opens new perspectives with which to develop optically opaque markers only traceable through this microwave technique.This paper has been financially supported through the grant reference BES-2016-077296 of the call Convocatoria de las ayudas para contratos predoctorales para la formacion de doctores de 2016 by Ministerio de Economia y Competitividad (MINECO) and by European Social Funds (ESF) of European Union, and the project SEDMICRON-TEC2015-70272-R (MINECO/FEDER) supported by Ministerio de Economia y Competitividad (MINECO) and by European Regional Development Funds (ERDF) of European Union.Gutiérrez Cano, JD.; Catalá Civera, JM.; Plaza González, PJ.; Penaranda-Foix, FL. (2021). Detection of Anti-Counterfeiting Markers through Permittivity Maps Using a Micrometer Scale near Field Scanning Microwave Microscope. Sensors. 21(16):1-14. https://doi.org/10.3390/s21165463S114211

    Dissipation-driven generation of two-qubit entanglement mediated by plasmonic waveguides

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    We study the generation of entanglement between two distant qubits mediated by the surface plasmons of a metallic waveguide. We show that a V-shaped channel milled in a flat metallic surface is much more efficient for this purpose than a metallic cylinder. The role of the misalignments of the dipole moments of the qubits, an aspect of great importance for experimental implementations, is also studied. A careful analysis of the quantum-dynamics of the system by means of a master equation shows that two-qubit entanglement generation is essentially due to the dissipative part of the effective qubit-qubit coupling provided by the surface plasmons. The influence of a coherent external pumping, needed to achieve a steady state entanglement, is discussed. Finally, we pay attention to the question of how to get information experimentally on the degree of entanglement achieved in the system.Comment: 13 pages, 12 figure

    Influence of Al2O3 Particle Size on Microstructure, Mechanical Properties and Abrasive Wear Behavior of Flame-Sprayed and Remelted NiCrBSi Coatings

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    The influence of micrometric alumina (low surface area-to-volume ratio) and nanometric alumina (high surface area-to-volume ratio) on microstructure, hardness and abrasive wear of a NiCrBSi hardfacing alloy coating applied to an AISI 304 substrate using flame spraying (FS) combined with surface flame melting (SFM) is studied. Remelting after spraying improved the mechanical and tribological properties of the coatings. Microstructural characterization using XRD, SEM and EDS indicated that alumina additions produced similar phases (NiSi, Ni3B, CrC and Ni31Si12) regardless of the alumina size, but the phases differed in morphology, size distribution and relative proportions from one coating to another. The addition of 12 wt.% nanometric Al2O3 increased the phases concentration more than five- to sixfold and reduced the hard phases size about four-to threefold compared with NiCrBSi + 12 wt.% micrometric Al2O3. Nanoalumina led to reduced mass loss during abrasive wear compared to micrometric alumina and greater improvement in hardness

    Thru reflect line calibration for empty substrate integrated waveguide with microstrip transitions

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    In past years, a great number of substrate integrated circuits have been developed. Among these new transmission lines, the substrate integrated waveguide (SIW) has received special attention. Although the quality factor and losses of these new integrated lines are better than the planar circuits, these characteristics are worst than in the case of waveguides, mainly due to the presence of dielectric substrate. To improve the performance of the integrated circuits, a new methodology for manufacturing the empty waveguides, without dielectric substrate, but at the same time completely integrated in a planar substrate, has been recently proposed, resulting in the novel empty SIW (ESIW). A low-cost and easy to manufacture thru reflect line calibration kit for de-embedding the effect of connectors and transitions when measuring ESIW devices is presented. Results prove the high quality of this calibration kit.Fernández Berlanga, M.; Ballesteros Garrido, J.; Martínez Cano, L.; Esteban González, H.; Belenguer Martínez, A. (2015). Thru reflect line calibration for empty substrate integrated waveguide with microstrip transitions. Electronics Letters. 51(16):1274-1276. doi:10.1049/el.2015.1393S127412765116Belenguer, A., Esteban, H., & Boria, V. E. (2014). Novel Empty Substrate Integrated Waveguide for High-Performance Microwave Integrated Circuits. IEEE Transactions on Microwave Theory and Techniques, 62(4), 832-839. doi:10.1109/tmtt.2014.2309637Deslandes, D., & Ke Wu. (2005). Analysis and design of current probe transition from grounded coplanar to substrate integrated rectangular waveguides. IEEE Transactions on Microwave Theory and Techniques, 53(8), 2487-2494. doi:10.1109/tmtt.2005.852778Engen, G. F., & Hoer, C. A. (1979). Thru-Reflect-Line: An Improved Technique for Calibrating the Dual Six-Port Automatic Network Analyzer. IEEE Transactions on Microwave Theory and Techniques, 27(12), 987-993. doi:10.1109/tmtt.1979.1129778Caballero, E. D., Boria, V. E., Belenguer, A., & Esteban, H. (2013). Thru-reflect-line calibration for substrate integrated waveguide devices with tapered microstrip transitions. Electronics Letters, 49(2), 132-133. doi:10.1049/el.2012.302
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