Electronic structure of the double perovskite Ba2Er(Nb,Sb)O 6

In this work, we present a detailed study of the structural and the electronic structure of the double perovskite Ba2Er(Nb,Sb)O 6. All calculations were performed with the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) based on the Density Functional Theory (DFT). From the minimization of energy as a function of volume using the Murnaghan's state equation has been obtained the equilibrium lattice parameter and the bulk modulus of these compounds. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the density of charge, showing that these compounds have a total magnetic moment of 3.0 μB per formula unit due to Er atoms.Fil: Gil Rebaza, Arles Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Deluque Toro, Crispulo Enrique. Universidad Popular del Cesar; ColombiaFil: Téllez Landínez, D. A. Universidad Nacional de Colombia; ColombiaFil: Roa Rojas, J.. Universidad Nacional de Colombia; Colombi

Link prediction in online social networks using group information

Users of online social networks voluntarily participate in different user groups or communities. Researches suggest the presence of strong local community structure in these social networks, i.e., users tend to meet other people via mutual friendship. Recently, different approaches have considered communities structure information for increasing the link prediction accuracy. Nevertheless, these approaches consider that users belong to just one community. In this paper, we propose three measures for the link prediction task which take into account all different communities that users belong to. We perform experiments for both unsupervised and supervised link prediction strategies. The evaluation method considers the links imbalance problem. Results show that our proposals outperform state-of-the-art unsupervised link prediction measures and help to improve the link prediction task approached as a supervised strategy.São Paulo Research Foundation (FAPESP) (grants 2011/22749-8 and 2013/12191-5)National Council for Scientific and Technological Development (CNPq) (grant 151836/2013-2)14th International Conference on Computational Science and its Applications (ICCSA).\ud Guimarães, Portugal. 30 June - 3 July 2014

Electronic structure of the double perovskite Ba2Er(Nb,Sb)O 6

In this work, we present a detailed study of the structural and the electronic structure of the double perovskite Ba2Er(Nb,Sb)O6. All calculations were performed with the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) based on the Density Functional Theory (DFT). From the minimization of energy as a function of volume using the Murnaghan's state equation has been obtained the equilibrium lattice parameter and the bulk modulus of these compounds. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the density of charge, showing that these compounds have a total magnetic moment of 3.0 μB per formula unit due to Er atoms.Instituto de Física La Plat

Electronic structure of the double perovskite Ba2Er(Nb,Sb)O 6

In this work, we present a detailed study of the structural and the electronic structure of the double perovskite Ba2Er(Nb,Sb)O6. All calculations were performed with the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) based on the Density Functional Theory (DFT). From the minimization of energy as a function of volume using the Murnaghan's state equation has been obtained the equilibrium lattice parameter and the bulk modulus of these compounds. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the density of charge, showing that these compounds have a total magnetic moment of 3.0 μB per formula unit due to Er atoms.Instituto de Física La Plat

Challenges and Opportunities in Finfish Nutrition

Much of the criticism leveled at aquaculture (e.g., dependency on animal-derived feedstuffs, nutrient-laden effluent discharges, and increased organic contamination in edible products) can be traced to the feeds in use. Accordingly, finfish nutritionists are being challenged to formulate feeds that not only meet the nutritional requirements of livestock but also minimize production costs, limit environmental impacts, and enhance product quality. These challenges not only add considerable complexity to finfish nutrition but also afford opportunities to avoid some of the mistakes made by other industries in the past. From a review of the current status of finfish nutrition with respect to major nutrient classes, we comment on future opportunities and promising avenues of research. Alternative protein sources, specifically those derived from marine bycatch, plants, and microbes, are discussed, as well as methods to facilitate their implementation in finfish feeds. Dietary lipid, its role in fish bioenergetics and physiology, and quality of aquaculture products is reviewed with special emphasis on alternative lipid sources and finishing diets. Carbohydrates and fiber are discussed in terms of nutrient-sparing, least-cost diet formulation and digestive physiology. Micronutrients are reviewed in terms of current knowledge of requirements and, along with other dietary immunostimulants, are given further consideration in a review of nutriceuticals and application in finfish feeds. The status of nutritional research in new aquaculture species is also outlined. By integrating classical approaches with emerging technologies, dietary formulations, and species, finfish nutritionists may identify means to increase production efficiency and sustainability and provide for the continued success of aquaculture

Dynamics of predator-prey models with refuge, harvesting and dispersal

The dynamics of predator-prey models with different prey harvesting functions and prey refuge is studied. This study includes a three-dimensional model to account for the dispersal of prey to a habitat where it is unavailable to the predator. Besides local stability analysis, one central question is how harvesting, refuge and dispersal could directly affect the dynamics of the ecosystem, such as existence and dynamics of coexistence equilibria and periodic solutions. Theoretical and numerical methods are used to prove the existence and to study the role played by several bifurcations in the mathematical models

Global Stability Analysis of a General Model of Zika Virus

Mathematical models of Zika virus dynamics are relatively new, and they mostly focus on either vector and horizontal, or vector and vertical transmission only. In this work,we first revisit a recent model that considers vector and vertical transmission, and we provide an alternative proof on the global stability of the disease-free equilibrium point. Then, a new and general model is presented which includes vector, horizontal and vertical transmission. For this new model, existence of both a disease-free and an endemic equilibrium is studied. Using matrix and graph-theoretic methods, appropriate Lyapunov functions are constructed and results on the global stability properties of both equilibria are established

Factores de riesgo para malaria por Plasmodium vivax en una población rural de Trujillo, Perú

Objetivo: Identificar los factores de riesgo asociados a malaria por Plasmodium vivax en una población rural de la cost norte del Perú (Laredo, Trujillo), entre marzo y octubre del 2004. Material y Métodos: Se aplicó un cuestionario a los casos de malaria y a sus respectivos controles; los casos fueron identificados por la presencia de cuadro clínico y examen microscópico positivo al parásito, y los controles fueron personas que no tuvieron la enfermedad, pareados por edad, sexo y localidad con respecto al caso. Se calculó el OR y el intervalo de confianza al 95% (IC95) con la regresión logística. Resultados: Se incluyeron 101 pares de casos y controles. Se identificó como factores de riesgo al antecedente familiar de malaria en el último año (OR: 4,62; IC95: 1,90 - 11,26), la presencia de una acequia a 100 metros o menos de vivienda (OR 4,61; IC95: 2,15 - 9,89) o de un pozo artesanal (OR: 10,93; IC95: 3,45 - 34,58). Conclusión: Los antecedentes familiares y la cercanía de la vivienda a potenciales criaderos son factores de riesgo para el desarrollo de malaria por P.vivax en la zona rural de Laredo