Ground state and constrained domain walls in Gd/Fe multilayers

The magnetic ground state of antiferromagnetically coupled Gd/Fe multilayers and the evolution of in-plane domain walls is modelled with micromagnetics. The twisted state is characterised by a rapid decrease of the interface angle with increasing magnetic field. We found that for certain ratios M(Fe):M(Gd), the twisted state is already present at low fields. However, the magnetic ground state is not only determined by the ratio M(Fe):M(Gd) but also by the thicknesses of the layers, that is the total moments of the layer. The dependence of the magnetic ground state is explained by the amount of overlap of the domain walls at the interface. Thicker layers suppress the Fe aligned and the Gd aligned state in favour of the twisted state. Whereas ultrathin layers exclude the twisted state, since wider domain walls can not form in these ultrathin layers

Un currículo para el estudio de la historia de la ciencia en Secundaria : la experiencia del Seminario Orotava de Historia de la Ciencia

The curricula of two disciplines on History of Science at the High School level have been elaborated as part of the activities of a singular experience, Seminario Orotava de Historia de la Ciencia. The philosophy of the design considers science as an essential part of culture and interdisciplinarity as the most fitted method of teaching and learnign in a significative way

Airborne ultrasonic vortex generation using flexible ferroelectrets

Cellular ferroelectrets exhibit interesting electromechanical- acoustical characteristics. Their recent appearance and remarkable properties open up new possibilities for the design and development of ultrasonic transducers. In particular, the feasibility of fabricating ultrasonic vortex generators using ferroelectret films is demonstrated in this work. To this end, a transducer prototype was built by gluing the material onto a tangential-helical surface (outer diameter: 40 mm, pitch: 3.45 mm). Experimental results agree well with the theoretical estimation of the pressure and phase of the acoustic field in the near field and far field, which corroborates the potential of ferroelectrets to customize special acoustic fields. Furthermore, the proposed fabrication procedure is inexpensive and represents a new alternative for exploring and analyzing the special characteristics of acoustical helical wavefront

Modelling the spatial and sectoral benefits of productivity enhancing innovations using a transport oriented multiregional IO framework: the ‘megatruck’ in Spain

We render operational the model outlined by Carter (1990) via the introduction of the research methods necessary for studying the spatial and sectoral (upstream and downstream) benefits of productivity-enhancing innovations within a real interregional input–output framework. As case study we examine the reduction in production costs derived from the adoption of longer and heavier vehicles in freight road transportation. We exploit a new Spanish regional table including a detailed disaggregation of the transportation sector. The productivity gains at the national level, resulting from a 30% reduction in transport costs, amount to 2.95% of the GVA at market prices. Results show that firms operating in this niche market appropriate most of the gross operation surplus (which increases by 10%), consistent with the existence of market power. The remaining transportation sectors see profits slightly worsened, suggesting limited substitution effects. A high regional heterogeneity exists because of the different input–output structuresThis work was supported by Ministerio de Fomento, Spain: [Grant Number P42-08

A Distributed Solution to Synchronous Multiparty Interaction

Multiparty interactions are the key to describe problems where three or more processes need to collaborate simultaneously in order to solve a problem, and this paper aims to show the way we have implemented this mechanism in a network computer. The main feature of our solution is that it is not bound up with the underlying network, so it is highly portable. We also report some experimental results that showthat our prototype performs quite well on low cost computers

Zooming in on VY CMa ejecta

The Atacama Large Millimeter/Submillimeter Array (ALMA), Cagliari, Italy 14–18 October 2019ALMA has allowed us to study the ejecta around evolved stars with unprecedented resolution. This extremely high resolution at the millimeter domain provides a unique tool to study the processes taking place in the innermost regions of these evolved stars. In particular, the processes leading to the mass ejections of the Red Supergiant stars are unknown. The pulsation process responsible for mass ejection in the intermediate mass AGB phase does not work in the high mass evolved stars. Therefore, studying the characteristics of the mass ejections near the photosphere of the massive stars is essential to constrain the processes leading to the observed gas ejection. In this sense, we have obtained interferometric maps in the range 231.7 ¿ 235.3 GHz of the ejecta around the Red Supergiant star VY CMa with an spatial resolution of 0.02>. These maps revealed a level of complexity higher than previously anticipated from previous observations. The complexity seems to be due both to structural and chemical processes. The molecular lines covered within these maps range from upper energies 19 up to 3400 K, tracing different excitation conditions. We will present a global view of the different structures observedThe research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 610256 (NANOCOSMOS). We would also like to thank the Spanish MINECO for funding support from grants CSD2009-00038, AYA2012-32032, AYA2016-75066-C2-1-P & AYA2016-78994-P. M.A. also thanks for funding support from the Ramón y Cajal programme of Spanish MINECO (RyC-2014- 16277)

ASASSN-16ae: A Powerful White-Light Flare on an Early-L Dwarf

We report the discovery and classification of SDSS~J053341.43+001434.1 (SDSS0533), an early-L dwarf first discovered during a powerful $\Delta V < -11$ magnitude flare observed as part of the ASAS-SN survey. Optical and infrared spectroscopy indicate a spectral type of L0 with strong H$\alpha$ emission and a blue NIR spectral slope. Combining the photometric distance, proper motion, and radial velocity of SDSS0533 yields three-dimensional velocities of $(U,V,W)=(14\pm13,-35\pm14,-94\pm22)$~km~s$^{-1}$, indicating that it is most likely part of the thick disk population and probably old. The three detections of SDSS0533 obtained during the flare are consistent with a total $V$-band flare energy of at least $4.9\times10^{33}$~ergs (corresponding to a total thermal energy of at least $E_{\rm tot}>3.7\times10^{34}$~erg), placing it among the strongest detected M dwarf flares. The presence of this powerful flare on an old L0 dwarf may indicate that stellar-type magnetic activity persists down to the end of the main sequence and on older ML transition dwarfs.Comment: 7 pages, 3 tables, 2 figures; accepted to ApJ Letters; updated to reflect referee response and proof correction

Local models-based regression trees for very short-term wind speed prediction

This paper evaluates the performance of different types of Regression Trees (RTs) in a real problem of very short-term wind speed prediction from measuring data in wind farms. RT is a solidly established methodology that, contrary to other soft-computing approaches, has been under-explored in problems of wind speed prediction in wind farms. In this paper we comparatively evaluate eight different types of RTs algorithms, and we show that they are able obtain excellent results in real problems of very short-term wind speed prediction, improving existing classical and soft-computing approaches such as multi-linear regression approaches, different types of neural networks and support vector regression algorithms in this problem.We also show that RTs have a very small computation time, that allows the retraining of the algorithms whenever new wind speed data are collected from the measuring towers.Ministerio de Ciencia y Tecnología ECO2010-22065-C03-02Ministerio de Ciencia y Tecnología TIN2011-28956-C02Junta de Andalucía P12-TIC-1728Universidad Pablo de Olavide APPB81309

A counterfactual impact evaluation of a bilingual program on students’ grade point average at a spanish university

This observational study intends to estimate the causal effects of an English as a Medium of Instruction (EMI) program (as predictor) on students Grade Point Average (GPA) (as outcome) at a particular University in Spain by using a Counterfactual Impact Evaluation (CIE). The need to address the crucial question of causal inferences in EMI programs to produce credible evidences of successful interventions contrasts, however, with the absence of experimental or quasi-experimental research and evaluation designs in the field. CIE approach is emerging as a methodologically viable solution to bridge that gap. The program evaluated here consisted in delivering an EMI program in a Primary Education Teacher Training Degree group. After achieving balance on the observed covariates and recreating a situation that would have been expected in a randomized experiment, three matching approaches such as genetic matching, nearest neighbor matching and Coarsened Exact Matching were used to analyze observational data from a total of 1288 undergraduate students, including both treatment and control group. Results show unfavorable effects of the bilingual group treatment condition. Potential interpretations and recommendations are provided in order to strengthen future causal evidences of bilingual education programs’ effectiveness in Higher Education.This work was supported by the Junta de Andalucía-funded Proyecto de Excelencia: “Análisis y Garantía de Calidad de la Educación Superior Plurilingüe en la Educación Superior de Andalucía [Junta de Andalusia-funded Project of Excelence: Analysis and Warrantee of the Quality of Plurilingual Higher Education in Andalucia] (AGCEPESA; Grant Agreement No. P12-SEJ − 1588)

A Spitzer/IRS Spectrum of the 2008 Luminous Transient in NGC 300: Connection to Proto-Planetary Nebulae

We present a Spitzer/IRS low-resolution mid-infrared spectrum (5-14 micron) of the luminous transient discovered in the nearby galaxy NGC 300 in May 2008. The spectrum, obtained three months after discovery, shows that the transient is very luminous in the mid-IR. Furthermore, the spectrum shows strong, broad emission features at 8 and 12 micron that are observed in Galactic carbon-rich proto-planetary nebulae. Combining these data with published optical and near-IR photometry obtained at the same epoch, we find that the mid-IR excess traced by the Spitzer spectrum accounts for ~20% of the total energy output. This component can be well explained by emission from ~3x10^-4 Msun of pre-existing progenitor dust at temperature ~400 K. The spectral energy distribution of the transient also shows a near-IR excess that can be explained by emission from newly-formed dust in the ejecta. Alternatively, both the near-IR and mid-IR excesses can together be explained by a single pre-existing geometrically thick dust shell. In light of the new observations obtained with Spitzer, we revisit the analysis of the optical spectra and kinematics, which were compared to the massive yellow-hypergiant IRC+10420 in previous studies. We show that proto-planetary nebulae share many properties with the NGC 300 transient and SN 2008S. We conclude that even though the explosion of a massive star (> 10 Msun) cannot be ruled out, an explosive event on a massive (6-10 Msun) carbon-rich AGB/super-AGB or post-AGB star is consistent with all observations of the transients and their progenitors presented thus far.Comment: 9 pages, 5 figures, 3 tables; references update