Elastic properties of LaNiO3_{3} from first-principles calculations

By applying density functional theory (DFT) approximations, we present a first-principles investigation of elastic properties for the experimentally verified phases of a metallic perovskite LaNiO$_{3}$. In order to improve the accuracy of calculations, at first we select the most appropriate DFT approaches according to their performance in reproducing the low-temperature crystalline structure and the electronic density of states observed for the bulk LaNiO$_{3}$. Then, we continue with the single-crystal elastic constants and mechanical stability for the most common rhombohedral as well as high-temperature cubic and strain-induced monoclinic phases. Together with the calculated single-crystal elastic constants, the deduced polycrystalline properties, including bulk, shear, and Young's moduli, Poisson's ratio, Vickers hardness, sound velocities, Debye temperature, and anisotropy indexes, remedy the existing gap of knowledge about the elastic and mechanical behaviour of LaNiO$_{3}$, at least from a theoretical standpoint.Comment: 16 pages, 2 figures, 3 table

Contribution of high-nl shells to electron-impact ionization processes

The contribution to electron-impact ionization cross sections from excitations to high-nl shells and a consequent autoionization is investigated. We perform relativistic subconfiguration-average and detailed level-to-level calculations for this process. Ionization cross sections for the W27+ ion are presented to illustrate the large influence of the high shells (n >= 9) and orbitals (l >= 4) in the excitation-autoionization process. The obtained results show that the excitations to the high shells (n >= 9) increase cross sections of the indirect ionization process by a factor of 2 compared to the excitations to the lower shells (n <= 8). The excitations to the shells with orbital quantum number l = 4 give the largest contribution comparedwith the other orbital quantum numbers l. Radiative damping reduces the cross sections of the indirect process approximately twofold in the case of the level-to-level calculations. Determined data show that the excitation-autoionization process contributes approximately 40% to the total ionization cross sections.Comment: 18 pages including 6 figures and 2 table

Cascade emission in electron beam ion trap plasma of W25+^{25+} ion

Spectra of the W$^{25+}$ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the $10 - 3$ nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6 nm in the electron beam ion trap plasma. Emission band at 4.5 to 5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to $4d^{9} 4f^{4} \rightarrow 4f^{3}$ transitions, while $4f^{2} 5d \rightarrow 4f^{3}$ transitions arise after the cascade emission is taken into account.Comment: 16 pages including 4 figures and 3 table

Interpreting microarray experiments via co-expressed gene groups analysis

International audienceMicroarray technology produces vast amounts of data by measuring simultaneously the expression levels of thousands of genes under hundreds of biological conditions. Nowadays, one of the principal challenges in bioinformatics is the interpretation of huge data using different sources of information. We propose a novel data analysis method named CGGA (Co-expressed Gene Groups Analysis) that automatically finds groups of genes that are functionally enriched, i.e. have the same functional annotations, and are co- expressed. CGGA automatically integrates the information of microarrays, i.e. gene expression profiles, with the functional annotations of the genes obtained by the genome-wide information sources such as Gene Ontology (GO)1. By applying CGGA to well-known microarray experiments, we have identified the principal functionally enriched and co-expressed gene groups, and we have shown that this approach enhances and accelerates the interpretation of DNA microarray experiments

Arte e gestalt-terapia: aproximações

O presente trabalho relaciona o poder de expressão da Arte com a Gestaltterapia, uma vez que, por um lado, essa abordagem terapêuticaexplora processos criativos e promove ampliação da visão de mundo e, por outro, a Arte é manifestação das possibilidades presentes. Assim, pretende-se correlacionar as duas áreas e refletir sobre a Arte como um instrumento terapêutico. Ao desenvolver a pesquisa,analisei o percurso histórico da Arte no ocidente e suas interpretações até hoje, refletindo sobre os conceitos de Belo e Beleza, uma vez que são essenciais para se compreender e definir a Arte. O trabalho faz uma crítica à incapacidade de se presenciar as coisas como elas aparecem, e da perda da capacidade humana de sentir o “sensível”. Por fim, a pesquisa aproximou essa discussão das reflexões trazidas pelaGestalt-terapia, que propõe autoconhecimento através da awareness. Assim, ambas as discussões podem se articular e, em última instância, a Arte pode se revelar também como um instrumento terapêutico, proporcionando uma modalidade terapêutica denominada arteterapi