Quantum phase transitions in alternating spin-(1/2, 5/2) Heisenberg chains

The ground state spin-wave excitations and thermodynamic properties of two types of ferrimagnetic chains are investigated: the alternating spin-1/2 spin-5/2 chain and a similar chain with a spin-1/2 pendant attached to the spin-5/2 site. Results for magnetic susceptibility, magnetization and specific heat are obtained through the finite-temperature Lanczos method with the aim in describing available experimental data, as well as comparison with theoretical results from the semiclassical approximation and the low-temperature susceptibility expansion derived from Takahashi's modified spin-wave theory. In particular, we study in detail the temperature vs. magnetic field phase diagram of the spin-1/2 spin-5/2 chain, in which several low-temperature quantum phases are identified: the Luttinger Liquid phase, the ferrimagnetic plateau and the fully polarized one, and the respective quantum critical points and crossover lines

O pequeno grupo "Oficina de Capoeira" no contexto da reforma psiquiátrica The small "Capoeira Workshop" group in the context of psychiatric reform

A Oficina de Capoeira nasceu a partir da necessidade de inter-relação entre o Hospital Psiquiátrico São Pedro e a Vila São Pedro, haja vista a construção dos Serviços Residenciais Terapêuticos em parte da área territorial da vila. Composta de moradores da vila e usuários do hospital, esta oficina foi escolhida como objeto de estudo devido a sua singularidade, diversidade e contextualização na reforma psiquiátrica. Este estudo objetiva esclarecer como se produz e se organiza o sistema Pequeno Grupo Oficina de Capoeira, utilizando como principal referencial o Paradigma da Complexidade de Edgar Morin. As informações foram registradas a partir de observações e anotações em diário de campo. Participaram da pesquisa os sujeitos que constituíram a Oficina de Capoeira. Esta proposta nos sugere outras possibilidades de intervenção em pequenos grupos no contexto da reforma psiquiátrica. Todavia, precisamos viver a heterogeneidade e a incerteza do sistema como possibilidade de produção de sujeitos criativos.<br>The Capoeira workshop was formed from the need to strengthen the relationship between the Hospital Psiquiátrico São Pedro and the Vila São Pedro neighborhood, considering the construction of the Residential Therapeutic Services unit in the neighborhood. Composed of local residents and users of the hospital, the workshop was chosen as an object of study due to its uniqueness, its diversity and for the way it places psychiatric reform in context. The study aimed to understand how the small Capoeira Workshop group is produced and organized. The principal theoretical reference for the study was the Complexity Paradigm of Edgar Morin. The data was collected from observations and notations in a field notebook. Study participants included the subjects who composed the Capoeira Workshop. This created other possibilities for intervention in small groups in the context of psychiatric reform. Nevertheless, we need to experience the heterogeneity and the uncertainty of the system as a possibility for the production of creative subjects