4,824 research outputs found

    Piezoelectric Thick Films: Preparation and Characterization

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    Paulo Freire y la revolución cubana: paralelos y confluencias. La contribución que precisamos

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    Nos hemos propuesto el estudio del contradictorio histórico que se aprecia, en las relaciones de Freire con la Revolución Cubana.  Interesa explorar la historia, en su perspectiva proyectiva, en tanto experiencia y resultado para aprendizajes que sumen lo mejor de la práctica y la teoría pedagógica caribeña y latinoamericana, al esfuerzo de perfeccionamiento del socialismo cubano, a la ciencia y experiencia compartida para las actuales resistencias y luchas contra el capital y su ideología deshumanizante, por la construcción de alternativas revolucionarias en Nuestra América. Defendemos una ciencia social de vocaccación crítica, comprometida, más propositiva. Y Paulo Freire en estos propósitos continúa como uno de los imprescindible

    Paulo Freire y la Revolución Cubana. 1959-1997: de la historia intelectual a la social

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    The aim of this article is to expose the research made on the historical-pedagogical ties of Paulo Freire with the Cuban Revolution. A qualitative methodology is used to precise in time, space and transcendence, the study object relationships. The contexts of the starting point, the interesting mosaic of international and national circumstances in which these relations have moved, the roots of the fight for freedom in the Caribbean, in Latin American and in the world, and the impact of the historical leading role of Freire and of the Cuban Revolution, the identities, parallels and confluences.El artículo tiene por objetivo exponer los vínculos histórico-pedagógicos de Paulo Freire con la Revolución cubana. Es resultado del Proyecto de Estudios Históricos del Centro de Estudios Educacionales Varona, de la Universidad de Ciencias Pedagógicas “Enrique José Varona” (La Habana). Se utiliza una metodología cualitativa para precisar en tiempo, espacio y trascendencia de las relaciones objeto de estudio. Se evalúan los contextos de partida, el interesante mosaico de circunstancias internacionales y nacionales en que se movieron estas relaciones, las raigales luchas emancipatorias caribeñas, latinoamericanas y mundiales de la época y el impacto del protagonismo histórico de Freire y de la Revolución cubana, sus identidades, paralelos y confluencias.&nbsp

    Effectiveness of a program of romana’s Pilates for non-specific low back pain: A pilot study

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    Objetivo: comprobar la efectividad del método Pilates Romana para conseguir una mayor flexibilidad de la columna, junto con una mejora en la movilidad de la misma, así como del dolor que presentan en su vida diaria los pacientes. Metodología: ensayo clínico con intención de tratar a treinta pacientes con dolor lumbar inespecífico. Asistieron a 15 sesiones, 2 veces a la semana, del Método Pilates Romana.. Se evaluaron parámetros tales como dolor, test de Schöber, SRS-22 y distancia dedos- suelo. Resultados. Se encontraron diferencias estadísticamente significativas con respecto al dolor (escala EVA), distancia dedos- suelo, test de Schöber (flexibilidad en plano sagital), flexión lateral (flexibilidad en plano frontal) y en varios ítems de la escala SRS-22, con valores de p<0,001. Por ello, este método puede ser usado para mejorar el dolor, la flexibilidad axial, la función y los aspectos relacionados con la calidad de vidaAim: to test the effectiveness of the Romana’s Pilates method to obtain increased flexibility, improvements in mobility, and reduced pain in daily life. Methodology: a clinical trial with intention-to-treat thirty patients with nonspecific low back pain. Participants attended 15 sessions, twice a week. The Romana’s Pilates method was taught by an external physiotherapist. Parameters such as pain, the Schober test, and the SRS-22 were evaluated. Results: Statistically significant differences in pain (VAS), the Schober test (flexibility in sagittal plane), lateral flexion (flexibility in frontal plane) and several items of the SRS-22 scale were found, with p <0.001. This method may be used to improve pain, axial flexibility, function and aspects related to the quality of life of patient

    p-Variations of vector measures with respect to vector measures and integral representation of operators

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    [EN] In this paper we provide two representation theorems for two relevant classes of operators from any p-convex order continuous Banach lattice with weak unit into a Banach space: the class of continuous operators and the class of cone absolutely summing operators. We prove that they can be characterized as spaces of vector measures with finite p-semivariation and p-variation, respectively, with respect to a fixed vector measure. We give in this way a technique for representing operators as integrals with respect to vector measures.J.M. Calabuig and O. Blasco were supported by Ministerio de Economia y Competitividad (Spain) (project MTM2011-23164). E.A. Sanchez-Perez was supported by Ministerio de Economia y Competitividad (Spain) (project MTM2012-36740-C02-02).Blasco De La Cruz, O.; Calabuig, JM.; Sánchez Pérez, EA. (2015). p-Variations of vector measures with respect to vector measures and integral representation of operators. Banach Journal of Mathematical Analysis. 9(1):273-285. https://doi.org/10.15352/bjma/09-1-20S2732859

    Real-Time and Low-Cost Sensing Technique Based on Photonic Bandgap Structures

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    This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.36.002707. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] A technique for the development of low-cost and high-sensitivity photonic biosensing devices is proposed and experimentally demonstrated. In this technique, a photonic bandgap structure is used as transducer, but its readout is performed by simply using a broadband source, an optical filter, and a power meter, without the need of obtaining the transmission spectrum of the structure; thus, a really low-cost system and real-time results are achieved. Experimental results show that it is possible to detect very low refractive index variations, achieving a detection limit below 2 x 10(-6) refractive index units using this low-cost measuring technique. (C) 2011 Optical Society of America[This work was funded by the Spanish Ministerio de Ciencia e Innovacion (MICINN) under contracts TEC2008-06333, JCI-009-5805, and TEC2008-05490. Support by the Universidad Politecnica de Valencia through program PAID-06-09 and the Conselleria d'Educacio through program GV-2010-031 is acknowledged.García Castelló, J.; Toccafondo, V.; Pérez Millán, P.; Sánchez Losilla, N.; Cruz, JL.; Andres, MV.; García-Rupérez, J. (2011). Real-Time and Low-Cost Sensing Technique Based on Photonic Bandgap Structures. Optics Letters. 36(14):2707-2709. https://doi.org/10.1364/OL.36.002707S270727093614Fan, X., White, I. M., Shopova, S. I., Zhu, H., Suter, J. D., & Sun, Y. (2008). Sensitive optical biosensors for unlabeled targets: A review. Analytica Chimica Acta, 620(1-2), 8-26. doi:10.1016/j.aca.2008.05.022Homola, J., Yee, S. S., & Gauglitz, G. (1999). Surface plasmon resonance sensors: review. Sensors and Actuators B: Chemical, 54(1-2), 3-15. doi:10.1016/s0925-4005(98)00321-9Kersey, A. D., Davis, M. A., Patrick, H. J., LeBlanc, M., Koo, K. P., Askins, C. G., … Friebele, E. J. (1997). Fiber grating sensors. Journal of Lightwave Technology, 15(8), 1442-1463. doi:10.1109/50.618377De Vos, K., Bartolozzi, I., Schacht, E., Bienstman, P., & Baets, R. (2007). Silicon-on-Insulator microring resonator for sensitive and label-free biosensing. Optics Express, 15(12), 7610. doi:10.1364/oe.15.007610Iqbal, M., Gleeson, M. A., Spaugh, B., Tybor, F., Gunn, W. G., Hochberg, M., … Gunn, L. C. (2010). Label-Free Biosensor Arrays Based on Silicon Ring Resonators and High-Speed Optical Scanning Instrumentation. IEEE Journal of Selected Topics in Quantum Electronics, 16(3), 654-661. doi:10.1109/jstqe.2009.2032510Xu, D.-X., Vachon, M., Densmore, A., Ma, R., Delâge, A., Janz, S., … Schmid, J. H. (2010). Label-free biosensor array based on silicon-on-insulator ring resonators addressed using a WDM approach. Optics Letters, 35(16), 2771. doi:10.1364/ol.35.002771Skivesen, N., Têtu, A., Kristensen, M., Kjems, J., Frandsen, L. H., & Borel, P. I. (2007). Photonic-crystal waveguide biosensor. Optics Express, 15(6), 3169. doi:10.1364/oe.15.003169Lee, M. R., & Fauchet, P. M. (2007). Nanoscale microcavity sensor for single particle detection. Optics Letters, 32(22), 3284. doi:10.1364/ol.32.003284García-Rupérez, J., Toccafondo, V., Bañuls, M. J., Castelló, J. G., Griol, A., Peransi-Llopis, S., & Maquieira, Á. (2010). Label-free antibody detection using band edge fringes in SOI planar photonic crystal waveguides in the slow-light regime. Optics Express, 18(23), 24276. doi:10.1364/oe.18.024276Toccafondo, V., García-Rupérez, J., Bañuls, M. J., Griol, A., Castelló, J. G., Peransi-Llopis, S., & Maquieira, A. (2010). Single-strand DNA detection using a planar photonic-crystal-waveguide-based sensor. Optics Letters, 35(21), 3673. doi:10.1364/ol.35.003673Luff, B. J., Wilson, R., Schiffrin, D. J., Harris, R. D., & Wilkinson, J. S. (1996). Integrated-optical directional coupler biosensor. Optics Letters, 21(8), 618. doi:10.1364/ol.21.000618Sepúlveda, B., Río, J. S. del, Moreno, M., Blanco, F. J., Mayora, K., Domínguez, C., & Lechuga, L. M. (2006). Optical biosensor microsystems based on the integration of highly sensitive Mach–Zehnder interferometer devices. Journal of Optics A: Pure and Applied Optics, 8(7), S561-S566. doi:10.1088/1464-4258/8/7/s41Densmore, A., Vachon, M., Xu, D.-X., Janz, S., Ma, R., Li, Y.-H., … Schmid, J. H. (2009). Silicon photonic wire biosensor array for multiplexed real-time and label-free molecular detection. Optics Letters, 34(23), 3598. doi:10.1364/ol.34.003598Povinelli, M. L., Johnson, S. G., & Joannopoulos, J. D. (2005). Slow-light, band-edge waveguides for tunable time delays. Optics Express, 13(18), 7145. doi:10.1364/opex.13.007145Garcia, J., Sanchis, P., Martinez, A., & Marti, J. (2008). 1D periodic structures for slow-wave induced non-linearity enhancement. Optics Express, 16(5), 3146. doi:10.1364/oe.16.003146Pérez-Millán, P., Torres-Peiró, S., Cruz, J. L., & Andrés, M. V. (2008). Fabrication of chirped fiber Bragg gratings by simple combination of stretching movements. Optical Fiber Technology, 14(1), 49-53. doi:10.1016/j.yofte.2007.07.00

    Handling magnetic and structural properties of EuMnO3 thin films by the combined effect of Lu doping and substrate strain

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    This work aims to understand the alterations induced by film/substrate lattice mismatch in structure, lattice dynamics and magnetic response of orthorhombic Eu1-xLuxMnO3 thin films within the range 0 ≤ x ≤ 0.4, when compared to results reported for ceramics with analogous composition. Thin films, which have been deposited onto Pt/Ti/SiO2/Si(100) oriented substrates via chemical method, exhibit noteworthy modifications in the magnetic ordering properties and, contrary to ceramics, do not show any sharp phase transition to the paramagnetic state. This reveals an induced ferromagnetic response in the films which is stable up to 100 K. X-ray diffraction and Raman spectroscopy measurements have been performed to identify the mechanically compressive state induced by the substrate and Lu doping. This facilitates insight into the magnetoelastic coupling effect in these films which is driven by alterations in electronic orbital overlapping and the associated antiferromagnetic superexchange interactions.publishe

    Testing Gaussianity on Archeops Data

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    A Gaussianity analysis using a goodness-of-fit test and the Minkowski functionals on the sphere has been performed to study the measured Archeops Cosmic Microwave Background (CMB) temperature anisotropy data for a 143 GHz Archeops bolometer. We consider large angular scales, greater than 1.8 degrees, and a large fraction of the North Galactic hemisphere, around 16%, with a galactic latitude b > 15 degrees. The considered goodness-of-fit test, first proposed by Rayner & Best (1989), has been applied to the data after a signal-to-noise decomposition. The three Minkowski functionals on the sphere have been used to construct a chi-square statistic using different thresholds. The first method has been calibrated using simulations of Archeops data containing the CMB signal and instrumental noise in order to check its asymptotic convergence. Two kind of maps produced with two different map-making techniques (coaddition and Mirage) have been analysed. Archeops maps for both Mirage and coaddition map-making, have been found to be compatible with Gaussianity. From these results we can exclude a dust and atmospheric contamination larger than 7.8% (90% CL). Also the non-linear coupling parameter f_{nl} can be constrained to be -800 < f_{nl} < 1100 at the 95% CL and on angular scales of 1.8 degrees. For comparison, the same method has been applied to data from the NASA WMAP satellite in the same region of sky. The 1-year and 3-year releases have been used. Results are compatible with those obtained with Archeops, implying in particular an upper limit for f_{nl} on degree angular scales.Comment: A&A accepted. The limits on the contamination and the fnl parameter have been improve

    Enhancement of resistivity and magnetization of Bi1-xLaxFe1-yMnyO3 ceramics by composition optimization

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    This work aims at studying the effect of La and Mn substituents on the structural, electrical and magnetic properties of Bi1-xLaxFe1-yMnyO3 (0≤x≤0.30; 0≤y≤0.20) at room temperature, in order to find out the optimal compositions that provide both high resistivity and remnant magnetization. The analysis of the XRD patterns and Raman spectra suggest a progressive transition from a rhombohedral for x0.20. Moreover, we observe satellite peaks associated with an incommensurate modulated (IM) orthorhombic structure for x≥0.15 with y = 0, and x = 0.20 with y = 0.10. We were able to achieve a decrease by several orders of magnitude of the leakage current density and the emergence of a weak ferromagnetic response in the range of compositions 0.10<x≤0.3 and 0<y<0.1. These improved physical properties are a consequence of the absence of secondary phases and the breaking of the spiral cycloid spin structure. In particular, the compositions within 0.18≤x≤0.30 and 0.01<y<0.05 with IM orthorhombic structure exhibit the lowest conductivity and highest remnant magnetization. The outcome of this work suggests an alternative route to enhance multiferroic properties of BiFeO3, with simultaneous La (0.10≤x≤0.30) and moderate Mn (0.01<y<0.1) substitution.publishe
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