Spin-filtering effect in the transport through a single-molecule magnet Mn12_{12} bridged between metallic electrodes

Electronic transport through a single-molecule magnet Mn$_{12}$ in a two-terminal set up is calculated using the non-equilibrium Green's function method in conjunction with density-functional theory. A single-molecule magnet Mn$_{12}$ is bridged between Au(111) electrodes via thiol group and alkane chains such that its magnetic easy axis is normal to the transport direction. A computed spin-polarized transmission coefficient in zero-bias reveals that resonant tunneling near the Fermi level occurs through some molecular orbitals of majority spin only. Thus, for low bias voltages, a spin-filtering effect such as only one spin component contributing to the conductance, is expected. This effect would persist even with inclusion of additional electron correlations.Comment: Accepted for publication at J. Appl. Phy

Spatial Adaptive Speckle Filtering Driven by Temporal Polarimetric Statistics and Its Application to PSI

Persistent scatterer (PS) interferometry (PSI) techniques are designed to measure ground deformations using satellite synthetic aperture radar (SAR) data. They rely on the identification of pixels not severely affected by spatial or temporal decorrelation, which, in general, correspond to pointlike PSs commonly found in urban areas. However, in urban areas, we can find not only PSs but also distributed scatterers (DSs) whose phase information may be exploited for PSI applications. Estimation of DS parameters requires speckle filtering to be applied to the complex SAR data, but conventional speckle filtering approaches tend to mask PS information due to spatial averaging. In the context of single-polarization PSI, adaptive speckle filtering strategies based on the exploitation of amplitude temporal statistics have been proposed, which seek to avoid spatial filtering on nonhomogeneous areas. Given the growing interest on polarimetric PSI techniques, i.e., those using polarimetric diversity to increase performance over conventional single-polarization PSI, in this paper, we propose an adaptive spatial filter driven by polarimetric temporal statistics, rather than single-polarization amplitudes. The proposed approach is able to filter DS while preserving PS information. In addition, a new methodology for the joint processing of PS and DS in the context of PSI is introduced. The technique has been tested for two different urban data sets: 41 dual-polarization TerraSAR-X images of Murcia (Spain) and 31 full-polarization Radarsat-2 images of Barcelona (Spain). Results show an important improvement in terms of number of pixels with valid deformation information, hence denser area coverage.This work was supported in part by the Spanish Ministerio de Economía y Competitividad and in part by the European Union FEDER funds under Project TEC2011-28201-C02-02

Measurement of National Non-Visible Wealth through Intellectual Capital

The economy of knowledge requires measures of national wealth that take into account aspects not contemplated by GDP, in order to portray the situation of a country more truthfully. In this paper, we use a new model to measure the intellectual capital of nations, adapted from microeconomics. It is based on the observation of hidden capital as implicit generator of long-term wealth, considering not only sustainability and social wellbeing, but also intangible assets such as human development, economic structure, international trade, foreign image and innovation. This empirical study reveals the importance of hidden capital in a nation’s wealth, making the difference where economic growth is concerned, as the most developed countries record the highest scores of efficiency in terms of intangible capital.knowledge economy indicators, hidden wealth, intangibles, GDP

Are all patches worth exploring? Foraging desert birds do not rely on environmental indicators of seed abundance at small scales

Background: Consumers should show strong spatial preferences when foraging in environments where food availability is highly heterogeneous and predictable. Postdispersal granivores face this scenario in most arid areas, where soil seed bank abundance and composition associates persistently with vegetation structure at small scales (decimetres to metres). Those environmental features should be exploited as useful pre-harvest information, at least to avoid patches predicted to be poor. However, we did not find the expected spatial association in the algarrobal of the central Monte desert by observing foraging seed-eating birds, a field technique influenced by how much they exploit visited patches. In this work we tested if the first stage of foraging by granivorous birds (patch visit, encounter or exploration) is positively associated with environmental indicators of patch quality by recording the removal of single seeds from 300 scattered experimental devices during seasonal trials. Spatial selectivity was analysed by comparing the structural characteristics of used vs. available microhabitats, and evaluated against bottom-up and top-down hypotheses based on our previous knowledge on local seed bank abundance, composition and dynamics. Their foraging activity was also explored for spatial autocorrelation and environmental correlates at bigger scales. Results: Postdispersal granivorous birds were less selective in their use of foraging space than expected if microhabitat appearance were providing them relevant information to guide their search for profitable foraging patches. No microhabitat type, as defined by their vegetation structure and soil cover, remained safe from bird exploration. Analyses at bigger temporal and spatial scales proved more important to describe heterogeneity in seed removal. Conclusions: Closeness to tall trees, probably related to bird territoriality and reproduction or to their perception of predation risk, seemed to determine a first level of habitat selection, constraining explorable space. Then, microhabitat openness (rather than seed abundance) exerted some positive influence on which patches were more frequently visited among those accessible. Selective patterns by birds at small scales were closer to our predictions of a top-down spatial effect, with seed consumption creating or strengthening (and not responding to) the spatial pattern and dynamics of the seed bank.Fil: Milesi, Fernando Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Grupo de Investigación en Ecología de Comunidades del Desierto; ArgentinaFil: Lopez de Casenave, Javier Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Grupo de Investigación en Ecología de Comunidades del Desierto; ArgentinaFil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Grupo de Investigación en Ecología de Comunidades del Desierto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia San Juan Bosco. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentin

Polarimetric Approaches for Persistent Scatterers Interferometry

In previous works, a general framework to exploit polarimetric diversity to optimize the results of persistent scatterers interferometry (PSI) was presented, but tested only with dual-pol data. In this paper, the performance of these algorithms is assessed using fully polarimetric data, acquired by the Radarsat-2 satellite over the urban area of Barcelona, Spain. In addition, two new highly efficient polarimetric optimization methods, mean intensity polarimetric optimization and joint diagonalization-based polarimetric optimization, are introduced and evaluated. Given the variety of dual-pol configurations provided by current polarimetric satellites, such as TerraSAR-X and Radarsat-2, and the upcoming launch of Sentinel-1, ALOS-2, and Radarsat Constellation Mission, a study has been also carried out to determine the best performing dual-pol configurations for polarimetric PSI. Subsidence maps of the area of study are computed for single-pol, dual-pol, and full-pol data, which show the increase in pixel density with valid deformation results as more polarimetric information is made available. In particular, for full-pol data we get an increase of up to 2.5 times more pixels for coherence-based PSI techniques (degraded resolution), and over four times more for amplitude-based approaches (full resolution), in comparison with single-pol data. Both higher density and quality of pixels yield better results in terms of coverage and accuracy.This work was supported in part by the Spanish Ministerio de Economía y Competitividad and European Union FEDER funds under Project TEC2011-28201-C02-02

Antejuicio político por delitos de función: propuesta de modificación del artículo 100° de la constitución política

El tema desarrollado en la presente tesis se encuentra relacionado con el mantenimiento del equilibrio de poderes de nuestro Estado, equilibrio que se ve afectado por la regulación actual de la prerrogativa del antejuicio político ap licado a los altos funcionarios públicos que cometan delitos en el ejercicio de su función. Es por ello, que para el desarrollo de la presente investigación se ha planteado la delimitación de un problema de investigación, el cual está centrado en verificar que actualmente nuestra normativa nacional no tiene congruencia constitucional, la cual ocasiona vulneraciones a principios de autonomía e independencia del Ministerio Público y Poder Judicial. Para ello, ha sido necesario trabajar con herramientas metodológicas como análisis de fuente documental, normativa y comparada. Finalmente se obtienen resultados, las cuales nos ayudan a brindar recomendaciones específicas respecto al tema en cuestió

Biogenic Silver Nanoparticles as Sensors of Cu2+ and Pb2+ in Aqueous Solutions

Biogenic Silver Nanoparticles as Sensors of Cu2+ and Pb2+ in Aqueous SolutionsSilver nanoparticles (Ag-NPs) were bio-synthesized using Camellia sinensis (green tea) aqueous extract. Nanoparticles prepared with 10-3 M AgNO3 solution, using 3mL of green tea extract and at 60˚C, have spherical shape with a mean diameter of 7nm. The formation of the nanoparticles was confirmed by UV-Vis spectrophotometry through studies of the surface plasmon resonance (SPR). The morphology, size and crystalline structure of the Ag-NPs were determined using high definition transmission electron microscopy (TEM). Moreover, these green synthesized Ag-NPs were found to exhibit good sensing properties towards Cu2+ and Pb2+ ions in aqueous solutions. This metal ions-sensing ability of the biogenic Ag-NPs was monitored by UV-Vis spectrophotometry (SPR analyses) and fluorescence spectroscopy

Combined heat and power using high-temperature proton exchange membrane fuel cells for housing facilities

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Recently, new alternatives to conventional energy sources such as fossil fuels are arising due to global problems related to climate change effect and energy shortage. In this context, fuel cells and combined heat and power technologies appear as a possible solution due to their ability to provide both electrical and thermal energy more efficiently compared to traditional methods. Related to this, high-temperature proton exchange membrane fuel cells offer the possibility of implementing combined heat and power systems, and they are also considered an efficient technology that emits less greenhouse gases. In this article a model predictive control based energy management system for a specific house is presented. Simulation and control models of the system are presented, together with dimensions and energy profiles used. Finally, control objectives and the proposed control algorithm are detailed, and the results when trying to match residential heat and power demands are discussed.Peer ReviewedObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantPostprint (author's final draft