Predicting Word Maturity from Frequency and Semantic Diversity: A Computational Study

Semantic word representation changes over different ages of childhood until it reaches its adult form. One method to formally model this change is the word maturity paradigm. This method uses a text sample for each age, including adult age, and transforms the samples into a semantic space by means of Latent Semantic Analysis. The representation of a word at every age is then compared with its adult representation via computational maturity indices. The present study used this paradigm to explore to the impact of word frequency and semantic diversity on maturation indices. To do this, word maturity indices were extracted from a Spanish incremental corpus and validated, using correlation scores with Age of Acquisition and Word Difficulty indices from previous studies. The results show that both frequency and semantic diversity predict word maturity but that the predictive capacity of frequency decreases as exposure to language increases. The latter result is discussed in terms of inductive processes suggested in previous studies

Ab initio study of low-dimensional metallic systems

In the present Doctoral Thesis we gather all the research performed by the graduate student Jorge Botana Alcalde. Broadly speaking, the work consisted in the study of the structural, electrical and magnetic properties of a spread of low-dimensional systems, made up with transition metals. We can divide said systems in two categories: ultrathin film of iron and chromium, where the two iron layers are sandwiched around a central chromium layer, and atomic clusters, either made of gold or of an alloy of bismuth and manganese. This work was done using ab initio techniques, i.e. from first principles. In our systems that means to solve the non-relativistic Schrödinger equation for a many-electron system. Our approach to such a complex problem was by means of the density functional theory (DFT), which transforms the many-body problem, considering each electron interacting with every one of the other electrons, to a single-body problem, where each electron interacts only with an effective potential created by the electron density. The implementation of this approach for the calculation of our systems was performed using the deMon (density of Montreal) DFT software

La ciencia y la tecnología en el desarrollo futuro de América Latina

"La superación del subdesarrollo de América resultará de la acción simultánea de diferentes políticas y estrategias. En todo caso, y cualesquiera sean los caminos elegidos, el acceso a una sociedad moderna - que es uno de los objetivos que se pretenden alcanzar por el desarrollo - supone necesariamente una acción decisiva en el campo de la investigación científico-tecnológica. Lentamente, América Latina comienza a adquirir conciencia de esta necesidad y de esta carencia lentamente y casi a regañadientes, quedan todavía muchos funcionarios que creen que la investigación es un lujo para los países desarrollados y muchos empresarios que circunscriben su función a adquirir patentes y pagar royalties. Todos aquellos que adoptan esta actitud pasiva, olvidan que la nación que descarte esta tarea corre el peligro de quedar marginada de la historia, ignorando el lenguaje de los países científica y técnicamente más avanzados y ostentando los viejos atributos de la soberanía como meros símbolos formales, vigentes, quizás, en un pasado que definitivamente terminó." - p.

Pressure-stabilized lithium caesides with caesium anions beyond the - 1 state

Main group elements usually assume a typical oxidation state while forming compounds with other species. Group I elements are usually in the +1 state in inorganic materials. Our recent work reveals that pressure may make the inner shell 5p electrons of Cs reactive, causing Cs to expand beyond the +1 oxidation state. Here we predict that pressure can cause large electron transfer from light alkali metals such as Li to Cs, causing Cs to become anionic with a formal charge much beyond -1. Although Li and Cs only form alloys at ambient conditions, we demonstrate that these metals form stable intermetallic LinCs ( n = 1-5) compounds under pressures higher than 100 GPa. Once formed, these compounds exhibit interesting structural features, including capped cuboids and dimerized icosahedra. Finally, we explore the possibility of superconductivity in metastable LiCs and discuss the effect of the unusual anionic state of Cs on the transition temperature.Botana, J. , & Miao, M. (2014). Pressure-stabilized lithium caesides with caesium anions beyond the-1 state. Nature Communications, 5, 4861-4868.2041-172

La técnica del Ánalisis de la Semántica Latente (LSA/LSI) como modelo informático de la comprensión del texto y el discurso: una aproximación distribuida al análisis semántico

Programa de doctorado de calidad: comprensión del texto y del discursoTesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Psicología. Departamento de Psicología Social y de Metodología. Fecha de lectura: 10 de diciembre de 2010El formato de esta tesis consiste en una colección de cuatro manuscritos individuales, que han sido recientemente aceptados o enviados para publicación a revistas internacionales de psicología experimental, lingüística o tecnología

Event-related brain potential evidence for animacy processing asymmetries during sentence comprehension

The animacy distinction is deeply rooted in the language faculty. A key example is differential object marking, the phenomenon where animate sentential objects receive specific marking. We used event-related potentials to examine the neural processing consequences of case-marking violations on animate and inanimate direct objects in Spanish. Inanimate objects with incorrect prepositional case marker ‘a’ (‘al suelo’) elicited a P600 effect compared to unmarked objects, consistent with previous literature. However, animate objects without the required prepositional case marker (‘el obispo’) only elicited an N400 effect compared to marked objects. This novel finding, an exclusive N400 modulation by a straightforward grammatical rule violation, does not follow from extant neurocognitive models of sentence processing, and mirrors unexpected “semantic P600” effects for thematically problematic sentences. These results may reflect animacy asymmetry in competition for argument prominence: following the article, thematic interpretation difficulties are elicited only by unexpectedly animate objects

Desarrollo de un cliente MQTT para comunicaciones seguras en sistemas embebidos

241 p. -- Bibliogr.: p. 240-241En el presente documento se expone el desarrollo de un cliente MQTT que permite realizar comunicaciones seguras mediante TLS, para ser usado en una aplicación que se ejecute sobre un sistema embebido. La aplicación creada también hace uso de otros protocolos TCP/IP, motivo por el cual se han desarrollado clientes adicionales que también son expuestos en este documento. El documento consta de dos partes. La primera parte es la memoria, y en ella se exponen aquellos aspectos teóricos y prácticos de los que es recomendable tener conocimiento para hacer uso del proyecto de programación creado, escrito en lenguaje C y que se encuentra en la segunda parte, de anexos

Thermal laser oxidation based texturing as finishing treatment for improving surface properties of UNS R56400

Thermal treatments are commonly applied for modifying surfaces in order to improve their functional behavior through obtaining specific microstructures introducing external elements into alloys or developing coatings, which provide improvements in the surface integrity of the treated samples. Thermal laser treatments allow controlling features and thickness, without affecting the rest of material. In this contribution, the effect of scan speed on changes in the surface integrity of UNS R56400 (Ti6Al4V) laser oxidized samples has been evaluated from the variations of material hardness supplied by the oxide layer. The possibility of microcracks development, mainly derived from the oxides compactness has been taken into account. Taking as reference the tribological behavior of the modified alloy, the objective is to determine the relationship between laser texturing conditions and the improvement of mechanical strength under friction and slip situations