Casimir repulsion between Topological Insulators in the diluted regime

The Pairwise Summation Approximation (PSA) of Casimir energy is applied to a system of two dielectrics with magnetoelectric coupling. In particular, the case of Topological Insulators (TI) is studied in detail. Depending on the the optical response of the TI, we obtain a stable equilibrium distance, atraction for all distances, or repulsion for all distances at zero temperature. This equilibrium distance disappears in the high temperature limit. These results are independent on the geometry of the TI, but are only valid in the diluted approximation.Comment: 6 pages, 4 figure

Impact of the Intensive Program of Emotional Intelligence (IPEI) on middle man-agers’ emotional intelligence

Background: This study aimed to evaluate the effect of the Intensive Program of Emo-tional Intelligence (IPEI; Fernández, 2015) on middle managers’ emotional intelligence, as this variable may have a significant impact on personal satisfaction, task performance, and work environment. Method: The intervention was applied on work team supervisors from a big call center, as it is an overlooked sector in this topic. Two-hundred and eighty-two supervisors from a Spanish multinational Madrid-based company (51.4% males and 48.6% females) participated in this study. Participants were assigned to the experimental group (n = 190) or the control group (n = 92) by availability, according to management decision. All supervisors filled in two questionnaires to evaluate the differ-ent components of intrapersonal emotional intelligence (i.e., attention, clarity, and repair; TMMS-24; Fernández-Berrocal, Extremera, & Ramos, 2004) and cognitive and affec-tive empathy (i.e., perspective taking, emotion understanding, empathic joy, and person-al distress; TECA; López-Pérez, Fernández, & Abad, 2008). Results: The findings showed an increase in the studied variables for the experimental group. Conclusions: The obtained results support middle managers’ training on emotional competences through short, efficient, and economic programs, and it was discussed potential limita-tions and implications of the obtained results

Robot-Aided Fabrication of Materially Efficient Complex Concrete Assemblies

This paper presents a novel approach for the materially efficient production of doubly-curved Expanded Polystyrene (EPS) form-work for insitu concrete construction and a novel application of a patented Glass Reinforced Concrete (GRC) technology. Research objectives focus on the development of complex form-work generation and concrete application via advanced computational and robotic methods. While it is viable to produce form-work with complex geometries with advanced digital and robotic fabrication tools, a key consideration area is the reduction of form-work waste material. The research agenda explores methods of associating architectural, spatial, and structural criteria with a material-informed holistic approach. The digital and physical investigations are founded on Robotic Hot-Wire Cutting (RHWC). The geometrical and physical principles of RHWC are transformed into design inputs, whereby digital and physical tests inform each other simultaneously. Correlations are set between form-work waste optimization with the geometrical freedom and constraints of hot-wire cutting via computational methods

A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass m c sin i c = 5.8 ± 1.9 M ⊕ and orbital period P c = 5.21 - 0.22 + 0.26 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.Peer reviewedFinal Published versio

Urea‑functionalized amorphous calcium phosphate nanofertilizers: optimizing the synthetic strategy towards environmental sustainability and manufacturing costs

This work has been performed thanks to the funding by Fondazione CARIPLO (Project No. 2016-0648: Romancing the stone: size-controlled HYdroxyaPATItes for sustainable Agriculture – HYPATIA). JMDL acknowledges Spanish Ministry of Science, Innovation and Universities of Spain (MCIU/AEI/FEDER, UE) for funding through the projects NanoVIT (RTI-2018-095794-A-C22) and NanoSmart (RYC-2016-21042). GBRR also acknowledges the Spanish MICIU for her postdoctoral contract within the Juan de la Cierva Program (JdC-2017). Financial support for this work was also provided by the Marie Skłodowska-Curie Standard Fellowships (888972-PSust- MOF, F.J.C.) within the European Union research and innovation framework programme (2014-2020). We thank Prof. Jan Skov Pedersen (Aarhus University, DK) for technical and scientific assistance on SAXS experiments.Nanosized fertilizers are the new frontier of nanotechnology towards a sustainable agriculture. Here, an efficient N-nanofertilizer is obtained by post-synthetic modification (PSM) of nitrate-doped amorphous calcium phosphate (ACP) nanoparticles (NPs) with urea. The unwasteful PSM protocol leads to N-payloads as large as 8.1 w/w%, is well replicated by using inexpensive technical-grade reagents for cost-effective up-scaling and moderately favours urea release slowdown. Using the PSM approach, the N amount is ca. 3 times larger than that obtained in an equivalent one-pot synthesis where urea and nitrate are jointly added during the NPs preparation. In vivo tests on cucumber plants in hydroponic conditions show that N-doped ACP NPs, with half absolute N-content than in conventional urea treatment, promote the formation of an equivalent amount of root and shoot biomass, without nitrogen depletion. The high nitrogen use efficiency (up to 69%) and a cost-effective preparation method support the sustainable real usage of N-doped ACP as a nanofertilizer.Fondazione Cariplo 2016-0648Spanish Ministry of Science, Innovation and Universities of Spain (MCIU/AEI/FEDER, UE) RTI-2018-095794-A-C22 RYC-2016-21042Marie Sklodowska-Curie Standard Fellowships within the European Union research and innovation framework programme (2014-2020) 888972-PSustMOFSpanish MICIU within the Juan de la Cierva Program (JdC-2017

Casimir interaction between inclined metallic cylinders

The Casimir interaction between one-dimensional metallic objects (cylinders, wires) displays unconventional features. Here we study the orientation dependence of this interaction by computing the Casimir energy between two inclined cylinders over a wide range of separations. We consider Dirichlet, Neumann and perfect metal boundary conditions, both at zero temperature and in the classical high temperature limit. For all types of boundary conditions, we find that at large distances the interaction decays slowly with distance, similarly to the case of parallel cylinders, and at small distances scales as the interaction of two spheres (but with different numerical coefficients). Our numerical results at intermediate distances agree with our analytic predictions at small and large separations. Experimental implications are discussed.Comment: 9 pages, 5 figure

Effect of finite temperature and uniaxial anisotropy on the Casimir effect with three-dimensional topological insulators

In this work we study the Casimir effect with three-dimensional topological insulators including the effects of temperature and uniaxial anisotropy. Although precise experimental values for the optical properties of these materials are yet to be established, qualitative analysis is still possible. We find qualitatively that the reported repulsive behavior and the equilibrium point are robust features of the system, and are favored by low temperatures and the enhancement of the optical response parallel to the optical axis. The dependence of the equilibrium point with temperature and with the topological magnetoelectric polarizability characteristic of three-dimensional topological insulators is also discussed.Comment: 17 pages, 7 figures. Published versio

Dynamical approach to the Casimir effect

Casimir forces can appear between intrusions placed in different media driven by several fluctuation mechanisms, either in equilibrium or out of it. Herein, we develop a general formalism to obtain such forces from the dynamical equations of the fluctuating medium, the statistical properties of the driving noise, and the boundary conditions of the intrusions (which simulate the interaction between the intrusions and the medium). As a result, an explicit formula for the Casimir force over the intrusions is derived. This formalism contains the thermal Casimir effect as a particular limit and generalizes the study of the Casimir effect to such systems through their dynamical equations, with no appeal to their Hamiltonian, if any exists. In particular, we study the Casimir force between two infinite parallel plates with Dirichlet or Neumann boundary conditions, immersed in several media with finite correlation lengths (reaction--diffusion system, liquid crystals, and two coupled fields with non-Hermitian evolution equations). The driving Gaussian noises have vanishing or finite spatial or temporal correlation lengths; in the first case, equilibrium is reobtained and finite correlations produce nonequilibrium dynamics. The results obtained show that, generally, nonequilibrium dynamics leads to Casimir forces, whereas Casimir forces are obtained in equilibrium dynamics if the stress tensor is anisotropic.Comment: 12 pages, 1 figur