Electron degeneracy and intrinsic magnetic properties of epitaxial Nb:SrTiO3_3 thin-films controlled by defects

We report thermoelectric power experiments in e-doped thin films of SrTiO$_3$ (STO) which demonstrate that the electronic band degeneracy can be lifted through defect management during growth. We show that even small amounts of cationic vacancies, combined with epitaxial stress, produce a homogeneous tetragonal distortion of the films, resulting in a Kondo-like resistance upturn at low temperature, large anisotropic magnetoresistance, and non-linear Hall effect. Ab-initio calculations confirm a different occupation of each band depending on the degree of tetragonal distortion. The phenomenology reported in this paper for tetragonally distorted e-doped STO thin films, is similarto that observed in LaAlO$_3$/STO interfaces and magnetic STO quantum wells.Comment: 5 pages, 5 figure

Theoretical X-Ray Absorption Debye-Waller Factors

An approach is presented for theoretical calculations of the Debye-Waller factors in x-ray absorption spectra. These factors are represented in terms of the cumulant expansion up to third order. They account respectively for the net thermal expansion $\sigma^{(1)}(T)$, the mean-square relative displacements $\sigma^2(T)$, and the asymmetry of the pair distribution function $\sigma^{(3)}(T)$. Similarly, we obtain Debye-Waller factors for x-ray and neutron scattering in terms of the mean-square vibrational amplitudes $u^2(T)$. Our method is based on density functional theory calculations of the dynamical matrix, together with an efficient Lanczos algorithm for projected phonon spectra within the quasi-harmonic approximation. Due to anharmonicity in the interatomic forces, the results are highly sensitive to variations in the equilibrium lattice constants, and hence to the choice of exchange-correlation potential. In order to treat this sensitivity, we introduce two prescriptions: one based on the local density approximation, and a second based on a modified generalized gradient approximation. Illustrative results for the leading cumulants are presented for several materials and compared with experiment and with correlated Einstein and Debye models. We also obtain Born-von Karman parameters and corrections due to perpendicular vibrations.Comment: 11 pages, 8 figure

Incidencias de las estrategias did?cticas frente a la adquisici?n y aprendizaje de la lengua de se?as colombiana en la comunidad sorda de la Instituci?n Educativa Ni?o Jes?s de Praga - Sede ITSOR

35 p. Recurso Electr?nicoEl objetivo principal de esta investigaci?n es determinar las incidencias de las estrategias did?cticas frente a la adquisici?n y aprendizaje de la Lengua de Se?as Colombiana ?LSC- en la comunidad sorda de la Instituci?n Educativa Ni?o Jes?s de Praga- Sede ITSOR. El enfoque que se utiliza es cualitativo y el m?todo estudio de caso. La muestra de la poblaci?n escogida es de un ni?o de seis (6) a?os del grado primero y un ni?o del grado segundo de once (11) a?os de estrato socio-econ?mico heterog?neo. Los instrumentos que se utilizaron: Entrevista semi estructurada, t?cnica de relatos de vida, y observaci?n participante y no participante. Despu?s de culminar el presente estudio se pretende determinar la incidencia en la adquisici?n y aprendizaje de la LSC en la primera infancia para la construcci?n del pensamiento concreto. La investigaci?n permitir? concluir que si el ni?o se encuentra expuesto a ambientes comunicativos permanente en LSC, mejorar? su avance en el aprendizaje, en el desarrollo lingu??stico y a su vez en el desarrollo integral.The main objective of the research is to determine the incidences of didactic strategies in the acquisition and learning of Colombian sign language in the deaf community of the Educational Institute Ni?o Jes?s de Praga - Sede ITSOR. The approach used is qualitative and the method utilized is the case studied. The sample population selected is a 6 year old child in grade primary and an 11 year old child in second grade of mixed socioeconomic strata. The following instruments are used: The semi-structured interview technique and observation of the participant and non-participant. After its completion, the present study aims to determine the impact of acquiring and learning Colombian sign language in early childhood on the construction of concrete thinking. The research leads to the conclusion that if the child is exposed to environments where there is constant communication in Colombian sign language, he will have improved progress in learning, language development and overall development. Keywords: Deaf people, Colombian sign language, learning

Modelos simplificados para a avaliação de estruturas existentes de B.A. e optimização do seu reforço

O estudo e desenvolvimento de metodologias simplificadas para a análise nãolinear dinâmica de estruturas irregulares, e, o desenvolvimento de ferramentas numéricas para a optimização de reforço têm um papel principal na avaliação e reforço de estruturas. Neste artigo é proposta uma metodologia simplificada para a análise dinâmica não-linear de edifícios baseada no cálculo espectral multi-modal da resposta sísmica. Esta metodologia simples fornece bons resultados, mesmo na análise de estruturas irregulares e constitui-se como uma ferramenta essencial para a optimização do reforço de edifícios existentes

Entrepreneurial Intentions: a bibliometric analysis

Purpose – The purpose of this research is to identify the main authors, the main influential universities doing research on EI, the main subject areas and the main productive academic journals on this topic. This paper also aims to shed light on the current knowledge and contributions to the field, in particular: co-authorships, co-words, research topics and cluster of themes. Methodology – The methodology is based on bibliometric techniques using mapping and clustering. The study has been conducted on 377 articles published in journals indexed in the Scopus database for a period of time of almost 24 years, from 01/01/1993 to 08/07/2016. VOSviewer software was used to conduct the analysis. Findings – Findings highlight the top authors, the ranking of the main journals and universities doing research in the field of EI. Another relevant contribution is the identification and classification of main research streams and gaps that have been highlighted. Originality/value – This paper is an attempt to clarify the state of the research and to analyse the progress of the studies on EI and to elaborate bibliometric studies that help to give some order to the variety of sources. This is helpful for new researchers approaching EI for the first time and also for those that are familiar with the field. Keywords Entrepreneurial intentions, bibliometric analysis, citation analysis, literature review Paper type Literature revie

Structural and functional stabilization of protein entities

XI Reunião Regional Nordeste da SBBq | 4th International Symposium in Biochemistry of Macromolecules and BiotechnologyStabilization of protein and protein-like molecules translates into preservation of both structure and functionality during storage and/or targeting, and such stabilization is mostly attained through establishment of a thermodynamic equilibrium with the (micro)environment. The basic thermodynamic principles that govern protein structural transitions and the interactions of the protein and/or peptide molecule with its (micro)environment will, therefore, be tackled. Protein stabilization is based upon dampening the molecular motions and, therefore, eliminating conformational transitions while the molecule is still in the native 3D (folded) state. The 3D structure of a protein molecule depends mostly on two types of interactions: intramolecular interactions between aminoacid moieties and intermolecular interactions with solute and/or solvent molecules present in its microenvironment. Stabilizing a biomolecule (aiming at preserving its function) involves dampening its molecular motions, and this can be achieved by reducing the chemical activity of the water present in its microenvironment, thus stabilizing both its structure and functionality. Recently, the simultaneous entrapment-stabilization of proteins and enzymes based on nanoencapsulation in a nanoemulsion (W/O/W) matrix with an hydrophilic core has started to gain momentum. Similarly to the stabilization mechanism of osmolytes, in nanoencapsulation the water activity is altered thus affecting the molecular motions of the proteins. Highlights will also be given to structural and functional stabilization of protein entities (viz. enzymes, (macro)peptides, (recombinant) proteins, and bacteriophages) by chemical methodologies. Modification of the biomolecules microenvironment via multipoint covalent attachment onto a solid surface followed by hydrophylic polymer coimmobilization, are some of the (latest) strategies that will be discussed.info:eu-repo/semantics/publishedVersio