Taming the resistive switching in Fe/MgO/V/Fe magnetic tunnel junctions: An ab initio study

A possible mechanism for the resistive switching observed experimentally in Fe/MgO/V/Fe junctions is presented. Ab initio total energy calculations within the local density approximation and pseudopotential theory shows that by moving the oxygen ions across the MgO/V interface one obtains a metastable state. It is argued that this state can be reached by applying an electric field across the interface. In addition, the ground state and the metastable state show different electric conductances. The latter results are discussed in terms of the changes of the density of states at the Fermi level and the charge transfer at the interface due to the oxygen ion motion

Cointegration in fractional systems with unknown integration orders.

Cointegrated bivariate nonstationary time series are considered in a fractional context, without allowance for deterministic trends. Both the observable series and the cointegrating error can be fractional processes. The familiar situation in which the respective integration orders are 1 and 0 is nested, but these values have typically been assumed known. We allow one or more of them to be unknown real values, in which case Robinson and Marinucci (1997,2001) have justified least squares estimates of the cointegrating vector, as well as narrow-band frequency-domain estimates, which may be less biased. While consistent, these estimates do not always have optimal convergence rates, and they have non-standard limit distributional behaviour. We consider estimates formulated in the frequency domain, that consequently allow for a wide variety of (parametric) autocorrelation in the short memory input series, as well as time-domain estimates based on autoregressive transformation. Both can be interpreted as approximating generalized least squares and Gaussian maximum likelihood estimates. The estimates share the same limiting distribution, having mixed normal asymptotics (yielding Wald test statistics with χ2 null limit distributions), irrespective of whether the integration orders are known or unknown, subject in the latter case to their estimation with adequate rates of convergence. The parameters describing the short memory stationary input series are √n-consistently estimable, but the assumptions imposed on these series are much more general than ones of autoregressive moving average type. A Monte Carlo study of finite-sample performance is included.

Majorana bound states in open quasi-1D and 2D systems with transverse Rashba coupling

We study the formation of Majorana states in quasi-1D and 2D square lattices with open boundary conditions, with general anisotropic Rashba coupling, in the presence of an applied Zeeman field and in the proximity of a superconductor. For systems in which the length of the system is very large (quasi-1D) we calculate analytically the exact topological invariant, and we find a rich phase diagram which is strongly dependent on the width of the system. We compare our results with previous results based on a few-band approximation. We also investigate numerically open 2D systems of finite length in both directions. We use the recently introduced generalized Majorana polarization, which can locally evaluate the Majorana character of a given state. We find that the formation of Majoranas depends strongly on the geometry of the system and if the length and the width are comparable no Majorana states can form, however, one can show the formation of "quasi-Majorana" states that have a local Majorana character, but no global Majorana symmetry.Comment: 12 pages, 13 figure

Kondo effect in transport through molecules adsorbed on metal surfaces: from Fano dips to Kondo peaks

The Kondo effect observed in recent STM experiments on transport through CoPc and TBrPP-Co molecules adsorbed on Au(111) and Cu(111) surfaces, respectively, is discussed within the framework of a simple model (Phys. Rev. Lett. {\bf 97}, 076806 (2006)). It is shown that, in the Kondo regime and by varying the adequate model parameters, it is possible to produce a crossover from a conductance Kondo peak (CoPc) to a conductance Fano dip (TBrPP-Co). In the case of TBrPP-Co/Cu(111) we show that the model reproduces the changes in the shape of the Fano dip, the raising of the Kondo temperature and shifting to higher energies of the dip minimum when the number of nearest neighbors molecules is lowered. These features are in line with experimental observations indicating that our simple model contains the essential physics underlying the transport properties of such complex molecules.Comment: 4 pages, 3 figures, submitted to PR

Flat Majorana bands in 2-d lattices with inhomogeneous magnetic fields: topology and stability

In this paper we show that for a range of configurations of inhomogeneous magnetic fields it is possible to create flat bands of Majorana states localized on the edges of 2-d lattices. Majorana bound states have been predicted to exist in both one dimensional and two dimensional systems with Rashba spin-orbit coupling, magnetic fields, and placed in proximity to a superconductor. For the proposed systems we present the bulk topological phase diagrams, and we study the conditions for weak topology which predicts the formation of bands of Majorana states. The Majorana bands are demonstrated to be relatively stable with respect to a variety of different perturbations on both square and hexagonal lattices.Comment: 13 pages, 17 figure

Who are you talking to? The role of addressee identity in utterance comprehension

Issue online: 30 March 2020Experimental evidence suggests that speaker and addressee quickly adapt to each other from the earliest moments of sentence processing, and that interlocutor-related information is rapidly integrated with other sources of nonpragmatic information (e.g., semantic, morphosyntactic, etc.). These findings have been taken as support for one-step models of sentence comprehension. The results from the present eventrelated potential study challenge this theoretical framework providing a case where discourse level information is integrated only at a late stage of processing, when morphosyntactic analysis has been already initiated. We considered the case of Basque allocutive agreement, where information about addressee gender is encoded in verbal inflection. Two different types of Basque grammatical violations were presented together with the corresponding control conditions: one could be detected based on a morphosyntactic mismatch (person agreement violation), while the other could be detected only if the addressee's gender was considered (allocutive violation). Morphosyntactic violations elicited greater N400 effects followed by P600 effects, while allocutive violations elicited only P600 effects. These results provide new constraints to one-step accounts as they represent a case where speakers do not immediately adjust to the addressee's perspective. We propose that the relevance of discourse-level information might be a crucial variable to reconcile the dichotomy between one- and two-step models.Horizon 2020 Framework Programme, Grant/Award Number: H2020-MSCAIF- 2018-837228; Fundación BBVA, Grant/ Award Number: IN[18]_HMS_LIN_0058; Ministerio de Economía y Competitividad, Grant/Award Number: IJCI-2016-27702, PSI2014-54500, RYC 2017-22015 and SEV-2015-490; Eusko Jaurlaritza, Grant/ Award Number: PI_2015_1_25; Gipuzkoa Fellowship Program, Grant/Award Number: FFI2016-76432-P. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 83722

Alinhamento interpessoal, representacional e morfossintático na Gramática Discursivo-Funcional

Este artigo se debruça sobre o mapeamento entre os Níveis Interpessoal, Representacional e Morfossintático da gramática, o chamado alinhamento, segundo o arcabouço da Gramática Discursivo-Funcional (GDF). Propõe uma tipologia das línguas baseada no que a sua organização morfossintática codifica: distinções pragmáticas (p.ex. em Tagalo), distinções semânticas (p.ex. em Achém), ou distinções inerentes à morfossintaxe (p.ex. em Inglês, Basco ou a língua Kham). A inclusão tanto do Sujeito como do Objeto e de línguas tanto acusativas como ergativas no tratamento do alinhamento morfossintático permitiu-nos abranger tipos tipologicamente mais variáveis e demonstrar o potencial da GDF para a análise contrastiva das línguas.<br>Within the framework of Functional Discourse Grammar (FDG), alignment concerns the relations between the Interpersonal, Representational and Morphosyntactic Levels of grammar. This article proposes a typology of languages based upon what we find to be encoded in their morphosyntactic organization: pragmatic distinctions (as in Tagalog), semantic distinctions (as in Acheh), or distinctions inherent to the morphosyntax (as in English, Basque and Kham). By including both subject and object, and both accusative and ergative languages in our treatment of morphosyntactic alignment, we provide a better coverage of typological variation and show the potential of FDG for cross-linguistic analysis

Role of age and comorbidities in mortality of patients with infective endocarditis

Purpose: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. Methods: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015. Patients were stratified into three age groups:<65 years, 65 to 80 years, and = 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. Results: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 = 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients =80 years who underwent surgery were significantly lower compared with other age groups (14.3%, 65 years; 20.5%, 65-79 years; 31.3%, =80 years). In-hospital mortality was lower in the <65-year group (20.3%, <65 years;30.1%, 65-79 years;34.7%, =80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%, =80 years; p = 0.003).Independent predictors of mortality were age = 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI = 3 (HR:1.62; 95% CI:1.39–1.88), and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared, the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. Conclusion: There were no differences in the clinical presentation of IE between the groups. Age = 80 years, high comorbidity (measured by CCI), and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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