Magnetism of two-dimensional defects in Pd: stacking faults, twin boundaries and surfaces

Careful first-principles density functional calculations reveal the importance of hexagonal versus cubic stacking of closed packed planes of Pd as far as local magnetic properties are concerned. We find that, contrary to the stable face centered cubic phase, which is paramagnetic, the hexagonal close-packed phase of Pd is ferromagnetic with a magnetic moment of 0.35 $\mu_{B}$/atom. Our results show that two-dimensional defects with local hcp stacking, like twin boundaries and stacking faults, in the otherwise fcc Pd structure, increase the magnetic susceptibility. The (111) surface also increases the magnetic susceptibility and it becomes ferromagnetic in combination with an individual stacking fault or twin boundary close to it. On the contrary, we find that the (100) surface decreases the tendency to ferromagnetism. The results are consistent with the magnetic moment recently observed in small Pd nanoparticles, with a large surface area and a high concentration of two-dimensional stacking defects.Comment: 8 pages, 10 figure

L’influence de la variable niveau socioculturel dans les formes d’adresse

En el presente artículo se muestran los resultados obtenidos en un estudio sobre la incidencia de la variable nivel sociocultural en la elección de las formas de tratamiento tú y usted en el español peninsular actual. Para llevarlo a cabo, en primer lugar se han estudiado las principales características de esta compleja variable sociolingüística y, a continuación, se ha realizado una encuesta a una muestra de un total de 190 estudiantes con edades comprendidas entre los 18 y los 25 años residentes en la ciudad de Salamanca. Para ello, se ha creado una encuesta ad hoc que contiene distintas situaciones comunicativas en las que se combinan variables sociales y contextuales, de acuerdo con la bibliografía especializada. Los resultados se han procesado estadísticamente y permiten observar el importante papel que desempeña en la elección pronominal el nivel sociocultural del interlocutor y también –aunque en menor medida– el del propio hablante.This article shows the results obtained in a study about the incidence of the social class variables when choosing between the address forms tú and usted in current peninsular Spanish. In order to carry this study out, the main characteristics of this variable have been primarily studied, and secondly, a survey was given to a sample of 190 students with ages between 18 and 25 years old who reside in the city of Salamanca (Spain). To do that, an ad hoc survey has been created, containing different communicative situations that combine social and contextual variables, according to the specialized bibliography. The results have been statistically processed and allow us to observe the important role that social class variables of the interlocutor, but also –to a lesser extent– of the speaker, take when choosing one of the pronouns.Cet article présente les résultats obtenus au cours d’une étude sur l’incidence de la variable du niveau socioculturel dans l’élection des formes d’adresse tú et usted en espagnol péninsulaire actuel. Pour réaliser l’étude, nous avons présenté les caractéristiques principales de cette complexe variable sociolinguistique et, ensuite, nous avons effectué une enquête sur un total de 190 étudiants d’entre 18 et 25 ans qui résident à Salamanque (Espagne). Pour ce faire, nous avons créé une enquête ad hoc qui contient différentes situations communicatives dans lesquelles sont combinées variables sociales et contextuelles, conformément à la bibliographie spécialisée. Les résultats ont été traités statistiquement et permettent d’observer l’importance du rôle du niveau socioculturel de l’interlocuteur et du locuteur –à une moindre échelle– dans l’élection pronominale

Lung tumorspheres as a drug screening platform against cancer stem cells

Treatment resistance and metastasis are linked to cancer stem cells (CSCs). This population represents a promising target, but remains unexplored in lung cancer. The main objective of this study was to characterize lung CSCs and discover new therapeutic strategies

Variación en la cortesía en la expresión de la petición en el español castellano y el portugués europeo

In this article we present the results of a contrastive analysis about the politeness strategies used in the expression of petitions in Castilian Spanish and European Portuguese. By using the DCT methodology, we have designed a questionnaire with petitions of different cost-benefit for the conversational partner and with variations relative to power and the social distance that exists between the participants. Once the data was gathered, we did a triple study about the differences in the expression of petitions: 1) between Spanish and Portuguese, 2) from the rank of imposition of the object and the petition, and 3) according to the social distance and the relative power of the participants. The results show that, although using different linguistic and politeness strategies, the expression of petitions is similar between Spanish and Portuguese speakers, although the latter take the social distance and the relative power of the hearer more into account than the Spanish speakers at the moment of choosing politeness forms.En este artículo se presentan los resultados de un análisis contrastivo de las estrategias de cortesía empleadas en la expresión de la petición en el español castellano y en el portugués europeo. A través de la metodología DCT, se ha diseñado un cuestionario con peticiones con distinto coste-beneficio para el interlocutor y con variaciones relativas al poder y a la distancia social existente entre los participantes. Una vez recopilados los datos, se ha realizado un triple estudio sobre las diferencias en la formulación de las peticiones: 1) entre el español y el portugués, 2) a partir del grado de imposición del objeto de la petición y 3) según la distancia social y el poder relativo de los interlocutores. Los resultados muestran que, a pesar de utilizar estrategias diferenciadas, la expresión de la petición es similar entre los hablantes de español y de portugués, si bien estos últimos tienen más en cuenta que los hispanohablantes la distancia social y el poder relativo del receptor en la elección de las formas de cortesía

MS-EMC vs. NEGF: A comparative study accounting for transport quantum corrections

As electronic devices approach the nanometer scale, quantum transport theories have been recognized as the best option to reproduce their performance. Other possible trend, mainly focused on reducing the computational effort, is the inclusion of quantum effects in semi-classical simulators. This work presents a comparison between a NEGF simulator and a MS-EMC tool including S/D tunneling both applied on a DGSOI transistor

Progressive myoclonus epilepsy KCNC1 variant causes a developmental dendritopathy

OBJECTIVE: Mutations in KCNC1 can cause severe neurological dysfunction, including intellectual disability, epilepsy, and ataxia. The Arg320His variant, which occurs in the voltage-sensing domain of the channel, causes a highly penetrant and specific form of progressive myoclonus epilepsy with severe ataxia, designated myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK). KCNC1 encodes the voltage-gated potassium channel KV 3.1, a channel that is important for enabling high-frequency firing in interneurons, raising the possibility that MEAK is associated with reduced interneuronal function. METHODS: To determine how this variant triggers MEAK, we expressed KV 3.1bR320H in cortical interneurons in vitro and investigated the effects on neuronal function and morphology. We also performed electrophysiological recordings of oocytes expressing KV 3.1b to determine whether the mutation introduces gating pore currents. RESULTS: Expression of the KV 3.1bR320H variant profoundly reduced excitability of mature cortical interneurons, and cells expressing these channels were unable to support high-frequency firing. The mutant channel also had an unexpected effect on morphology, severely impairing neurite development and interneuron viability, an effect that could not be rescued by blocking KV 3 channels. Oocyte recordings confirmed that in the adult KV 3.1b isoform, R320H confers a dominant negative loss-of-function effect by slowing channel activation, but does not introduce potentially toxic gating pore currents. SIGNIFICANCE: Overall, our data suggest that, in addition to the regulation of high-frequency firing, KV 3.1 channels play a hitherto unrecognized role in neuronal development. MEAK may be described as a developmental dendritopathy