BaZrO3 Photoluminescence Property: An Ab Initio Analysis of Structural Deformation and Symmetry Changes

This article reports a theoretical study based on experimental results for barium zirconate, BaZrO3 (BZ) thin films, using periodic mechanic quantum calculations to analyze the symmetry change in a structural order-disorder simulation. Four periodic models were simulated using CRYSTAL98 code to represent the ordered and disordered BZ structures. The results were analyzed in terms of the energy level diagrams and atomic orbital distributions to explain and understand the BZ photoluminescence properties (PL) at room temperature for the disordered structure based on structural deformation and symmetry changes. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 111: 694-701, 2011

Electronic and structural properties of the (10(1)over-bar0) and (11(2)over-bar0) ZnO surfaces

The structural and electronic properties of ZnO (10 (1) over bar0) and (11 (2) over bar0) surfaces were investigated by means of density functional theory applied to periodic calculations at B3LYP level. The stability and relaxation effects for both surfaces were analyzed. The electronic and energy band properties were discussed on the basis of band structure as well as density of states. There is a significant relaxation in the (10 (1) over bar0) as compared to the (11 (2) over bar0) terminated surfaces. The calculated direct gap is 3.09, 2.85, and 3.09 eV for bulk, (10 (1) over bar0), and (11 (2) over bar0) surfaces, respectively. The band structures for both surfaces are very similar.

Intercalation processes and diffusion paths of lithium ions in spinel-type structured Li(1+x)Ti(2)O(4): Density functional theory study

Intercalation processes and corresponding diffusion paths of Li ions into spinel-type structured Li(1+x)Ti(2)O(4) (0 <= x <= 0.375) are systematically studied by means of periodic density functional theory calculations for different compositions and arrangements. An analysis of the site preference for intercalation processes is carried out, while energy barriers for the diffusion paths have been computed in detail. Our results indicate that the Li insertion is thermodynamically favorable at octahedral sites 16c in the studied composition range, and Li migration from tetrahedral sites 8a to octahedral sites 16c stabilizes the structure and becomes favorable for compositions x >= 0.25. Diffusion paths from less stable arrangements involving Li migrations between tetrahedral and octahedral sites exhibit the lowest energy barrier since the corresponding trajectories and energy profiles take place across a triangle made by three neighboring oxygen anions without structural modification. Theoretical and experimental diffusion coefficients are in reasonable agreement.

Structural analyzes of the use of residues of tires in reinforced concrete

The search for an adequate destination to the tires without use is a problem for many countries. The use of tire rubber in concrete through the partial substitution of the small aggregate has for objective the withdrawal of this material of the environment besides serving as alternative material in places that present sand scarcity. However, to use this type of concrete in civil construction it's necessary to verify its structural behavior. The behavior of the adherence enters the bar of armor and the concrete surrounding it has decisive importance with relation to the load capacity of the structures of reinforced concrete. In this context, this work presents, argues and evaluates the results of the experimental studies for determination of the adherence tension according to pulling up assays pull-out normalized for CEB RC6 and also related in the ASTM C-234 in concrete with and without rubber residues. Armors of nominal diameter of 10,0; 12,5 and 16 mm had been used and concrete contend 10% of rubber fibres in substitution to the sand in volume.

Temperature dependence of structural and electronic properties of the spin-liquid candidate κ-(BEDT-TTF) 2Cu 2(CN) 3

We investigate the effect that the temperature dependence of the crystal structure of a two-dimensional organic charge-transfer salt has on the low-energy Hamiltonian representation of the electronic structure. For that, we determine the crystal structure of κ-(BEDT-TTF) 2Cu 2(CN) 3 for a series of temperatures between T=5 and 300 K by single crystal X-ray diffraction and analyze the evolution of the electronic structure with temperature by using density functional theory and tight binding methods. We find a considerable temperature dependence of the corresponding triangular lattice Hubbard Hamiltonian parameters. We conclude that even in the absence of a change of symmetry, the temperature dependence of quantities like frustration and interaction strength can be significant and should be taken into account. © 2012 American Physical Society.

Structural reforms, macroeconomic fluctuations and income distribution in Brazil

Includes bibliography

Employment and structural mobility. Revisiting a Prebischian theme

Includes bibliography

Structural change and domestic technological capabilities

Includes bibliography

Relative prices in Latin America in periods of low inflation and structural change

Includes bibliography

Structural enrichment reduces aggression in Tilapia rendalli

Environmental enrichment seeks to improve the behavior of captive animals. Few studies have developed enrichment strategies for fish, particularly for use in aquaculture. Environmental enrichment for territorial and aggressive animals has the potential to increase both the amount of defensible resources and the value of a disputed territory which can increase the level of aggression. This study evaluated this hypothesis for the redbreast tilapia, Tilapia rendaIli. We used a short-term approach for evaluation of fish aggressive behavior by recording it for 30 min after introduction of a pair of fish into each experimental aquarium. Our main finding was that the latency to start a fight was lower in an enriched environment, but the frequency of attacks was higher in a non-enriched environment (control). Furthermore, we observed clear hierarchical behavior (submissive dark stripes on the body and dominant light-colored bodies without stripes) only in the non-enriched environment. Structural enrichment of the environment for redbreast tilapia leads to decreased aggression and cohabitation without hierarchical dominance. © 2013 Copyright Taylor and Francis Group, LLC.

A theoretical and experimental study to unequivocal structural assignment of tetrahydroquinoline derivatives

The tetrahydroquinoline derivatives can be easily synthesized through Povarov reaction and have several important biological activities. This work describes a comparative study for the unequivocal assignment of molecular structure of different tetrahydroquinoline derivatives, through a complete analysis of NMR 1D and 2D NMR spectra (1H, 13C, COSY, HSQC, and HMBC), and the correlation this data with theoretical calculations of energy-minimization and chemical shift (δ), employing the theory level of DFT/B3LYP with set of the cc-pVDZ basis. For these derivatives the experimental analyses and the theoretical model adopted were sufficient to obtain a good description of its structures, and these results can be used to assign the structure of various others tetrahydroquinoline derivatives. © 2013 Springer Science+Business Media New York.

The Caribbean and the post-2015 development agenda

This paper will contend that the post-2015 development agenda presents a major opportunity for Caribbean countries to reverse decades of lagging economic performance and make the transition to balanced, holistic, and people-centred growth and development. The MDGs, while valuable in promoting gains in poverty reduction, health, education, nutrition, and maternal well-being were not tailored to the growth and development needs of the region. This can now be changed by a post-2015 development agenda which goes beyond improving the welfare of citizens by meeting basic needs and enhancing access to primary services. The necessary scaling-up of the MDG framework will require that the sustainable development goals, which will anchor the post- 2015 development agenda, are capable of promoting structural change, competitiveness and output gains while advancing social development and meeting environmental concerns. They must also address the unfinished business of the millennium development goals, primarily in the area of human development.

Currículo e formação docente no curso de ciências sociais/UFPA: configurações, continuidades e rupturas (1963-2011)

A tese investiga os desenhos curriculares do curso de Ciências Sociais da Universidade Federal do Pará. campus de Belém no período de 1963-2011. com o objetivo principal de refletir sobre o lugar da formação docente no referido curso. tendo em vista a relação que se estabelece entre o bacharelado e a licenciatura. De forma mais especifica, o estudo intenciona investigar e analisar as principais orientações que foram estabelecidas pelas propostas curriculares para 3 formação docente, assim como identificar como foram estruturados os desenhos curriculares para o referido curso e a forma como são contempladas as disciplinas voltadas para a licenciatura. A pesquisa foi feita a partir de levantamento bibliográfico sobre a temática em bibliotecas físicas e banco de dados virtuais, pesquisa documental realizada sobre os desenhos curriculares. Resoluções, ementas entre outros. Utilizou-se também de entrevistas semiestruturadas realizadas com docentes do curso com o objetivo de aprofundar e esclarecer questões não contidas nos documentos. O estudo utilizou como referencial teórico principal as contribuições da teoria critica do currículo, principalmente das obras de Michael Young, Basil Bernstein, António Flávio Moreira entres outros. Os resultados da pesquisa revelaram que as configurações locais dos desenhos curriculares do curso de Ciências Sociais deve-se em grande parte à fatores estruturais do sistema educacional brasileiro e que a consolidação da pós-graduação, em meados da década de 1960 e inicio de 1970, contribuiu para a aumentar a hierarquização entre as atividades de ensino e pesquisa, entre a graduação e a pós-graduação, entre o campo acadêmico e o escolar nos cursos de Ciências Sociais. As reformulações curriculares ocorridas no curso de Ciências Sociais mantiveram os padrões curriculares para a maioria dos cursos de Ciências Sociais no país desde sua criação. Os desenhos curriculares do curso de Ciências Sociais analisados se orientam por unia concepção de formação docente pautada no modelo de racionalidade técnica que favorece a separação entre a formação conteudista e a formação pedagógica, entre teoria e prática. Apesar das inúmeras reformulações curriculares ocorridas no curso de Ciências Sociais estas alterações mantiveram uma estrutura de organização disciplinar sob a tipologia do currículo coleção. em que as disciplinas singulares são orientadas para seu próprio desenvolvimento e protegidas por limites e hierarquias fortes. O currículo coleção caracterizado pelo enquadramento e classificação forte promove o isolamento entre as áreas do conhecimento o que contribuiu para a demarcação de fronteiras rígidas entre o campo das Ciências Sociais e Educação, entre a formação voltada para pesquisador e a formação orientada para professor.

Immediate graft histological assay, post pig's liver transplantation

PURPOSE: To describe the vascular and tissue histopathological changes in seven sequential experimental liver transplantations in pigs. METHODS: Fourteen female pigs, Sus domesticus species, with body mass between 5 and 8 kg were utilized. After the end of all anastomoses of the graft implantation in the receptor, the animal was monitored for 30 minutes, and at its end one of the biopsies was collected for histological analysis. The histological criteria utilized were: lytic hepatocyte necrosis, density of septal and portal inflammatory infiltrated, sinusoidal congestion and hemorrhage. The analysis was performed separately for the portal region in zone 1, 2 and 3. RESULTS: Among the structural changes undergone by the graft, those with greater frequency and intensity were vascular congestion and steatosis, which stood out in transplantations 5, 6 and 7. CONCLUSIONS: The technique demonstrated vascular alterations represented by vasocongestion, edema and minimum inflammatory reaction. In relation to the parenchyma, was observed macrovacuolar pan-acinar steatosis, focal lytic and occasional hemorrhages, beyond the accumulation of hemosiderin in Kuppfer's cells.

Structural, electronic and optical properties of Fe(III) complex with pyridine-2,6-dicarboxylic acid: A combined experimental and theoretical study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)