Magnetic polarons in Ca_(1-x)Y_xMnO_3

Experimental evidence show that in the magnetoresistive manganite Ca_(1-x) Y_xMnO_3, ferromagnetic (FM) polarons arises in an antiferromagnetic (AF) background, as a result of the doping with Yttrium. This hypothesis is supported in this work by classical Monte Carlo (MC) calculations performed on a model where FM Double Exchange (DE) and AF Superexhange (SE) compite.Comment: 3 pages, 3 figs, submitted to LAW3M conferenc

“The discontinuity in the continuity”. Michel Foucault and the archaeological period

Undoubtedly, the topic of discontinuity has got to an extent where it has captured the attention of a good number of researchers. These researchers devote themselves to reflect on the philosophy of the French thinker. Focusing on discontinuity promises to open a new line of analysis that, perhaps, will allow the revaluation of its scope in relation to its philosophical contributions. For such a task, first, we will approach the notion of history in Foucauldian thought to study the development this notion has with the discontinuity; followed by a study of the archaeological method to unravel whether it is possible to analyze discontinuity through an archaeological view. Would it be possible to look at the topic of discontinuity as a characteristic feature of this French philosopher's thinking? This document aims to answer this question

Socio-Spatial Implications of Street Market Regulation Policy: The Case of Ferias Libres in Santiago de Chile

Unlike in most Latin American cities, street vendors organized in farmers’ markets popularly known as ferias libres in Santiago de Chile, gained legal recognition early in the twentieth century. Since then, comunas, or local municipalities, have provided vendors with individual licenses that stipulate the place and time of operations, and have defined a clear set of rules regarding customer service. However, this early legal recognition has not necessarily overcome the embedded conflict over the economic use of public space. As supermarkets become spatially positioned along the main streets within easy access of the city’s transportation system, feriantes, or licensed street vendors, are being relocated in less profitable areas. Moreover, coleros, or unlicensed vendors, are still flourishing despite efforts to restrict their numbers.informal sector, regulation, farmers’ markets, competition

Normal functionals on Lipschitz spaces are weak∗^\ast continuous

Let $\operatorname{Lip}_0(M)$ be the space of Lipschitz functions on a complete metric space $M$ that vanish at a base point. We show that every normal functional in $\operatorname{Lip}_0(M)^\ast$ is weak$^*$ continuous, answering a question by N. Weaver.Comment: v2: Revised versio

Modeling and analysis of market share dynamics in a duopoly subject to affine feedback advertising policies and delays

Presents extensions of the Vidale-Wolfe and Lanchester models for market share duopoly dynamics. The novelties in the proposed extensions are the explicit introduction of a set of undecided clients into existing models, which consider only the sets of clients of the two competing firms, as well as the use of decentralized affine feedback advertising policies. It is shown that, under the proposed class of advertising policies, the extended Vidale-Wolfe and Lanchester models, despite having different dynamics, have equilibria in identical locations, with the same stability properties. The introduction of a third set of undecided clients also motivates the introduction of a more elaborate model of market share dynamics based on the replicator-mutator model from evolutionary game theory. This is done by identifying strategies with the entries of a preference matrix consisting of the choice preferences of firms by clients and the mutation matrix representing transition probabilities from one set of clients to another. The proposed model is analysed with respect to equilibria and their stability properties, as well as parametric sensitivity, under the proposed advertising policies. All proposed models are analysed for stability, the presence of oscillations, existence of Hopf bifurcations when implementation or adoption delays are introduced. The extended models of Vidale-Wolfe and Lanchester are robust to implementation delays, while for adoption delays, bifurcations can occur. The proposed replicator-mutator model is robust for both types of delays.Apresenta extensões aos modelos de Vidale-Wolfe e Lanchester para a dinâmica de duopólios. As novidades nas extensões propostas são a introdução explícita de um conjunto de clientes indecisos nos modelos existentes, os quais consideram apenas os conjuntos de clientes das duas empresas concorrentes, e o uso de políticas de publicidade afins com realimentação. Demonstra-se que sob a classe proposta de políticas de publicidade, os modelos estendidos de Vidale-Wolfe e Lanchester, apesar de terem dinâmicas diferentes, apresentam pontos de equilíbrio idênticos com as mesmas propriedades de estabilidade. A introdução de um terceiro conjunto de clientes indecisos também motiva a introdução de um modelo mais elaborado da dinâmica de mercado baseado no modelo Replicador-Mutador da teoria dos jogos evolucionários. A proposta do modelo é realizada identificando estratégias com elementos de uma matriz de preferência consistindo nas preferências de escolha das empresas pelos clientes e a matriz de mutação representa probabilidades de transição de um conjunto de clientes para outro. O modelo proposto é analisado em relação aos pontos de equilíbrios e suas propriedades de estabilidade, bem como a sensibilidade paramétrica sob as políticas de publicidade propostas. Todos os modelos propostos são analisados quanto à estabilidade, a presença de oscilações, a existência de bifurcações de Hopf quando atrasos de implementação ou de adoção são introduzidos. Os modelos estendidos de Vidale-Wolfe e Lanchester são robustos para atrasos em implementação enquanto que para o atraso de adoção apresentam a existência de bifurcações. O modelo Replicador-Mutador proposto é robusto para ambos tipos de atrasos

Double exchange model for RuSr_2(Eu,Gd)Cu_2O_8

We propose a double exchange model to describe the RuO_2 planes of RuSr_2(Eu,Gd)Cu_2O_8. The Ru^+5 ions are described by localized spins, and additional electrons provided by the superconducting CuO_2 planes are coupled ferromagnetically to them by Hund rules coupling. We calculate the spin structure factor, magnetic susceptibility and magnetization as a function of magnetic field and temperature, using a Monte Carlo algorithm in which the Ru^+5 spins are treated as classical. Several experiments which seemed in contradiction with one another are explained by the theory.Comment: 3 pages, 3 figs., submitted to LAW3M conferenc

Potential gains for Bolivia of the subscription of an association Agreement with the European Union

The liberalization trading has become a really important factor to determine both, the economic growth and the level of poverty in a country. It can be observed that in developed countries, international trading is essential, while in most of the developing countries do not get the same benefits. Although commercial openness could not raise the economic welfare in the same proportion in all of the countries where it was applied, it is still a model used in order to achieve development. The following paper looks for determining, theorically and empirically, the impacts of an Association Agreement with the European Union over the economy in general and the poverty levels. Then, a specific case is used, when talking about the impacts on the exports of quinoa and the benefits that the raise in the exports of this product can bring to the rural communities that produce it. The paper concludes that the only way to get the benefits of the Association Agreement with the European Union is to diversify the products that Bolivia exports and use more modern technology that can give the products a higher aggregate value.Economic Growth; Poverty; Export; Bolivia; European Union; Quinua; Added Value; diversification; Technology