Dynamical matrix for arbitrary quadratic fermionic bath Hamiltonians and non-Markovian dynamics of one and two qubits in an Ising model environment

We obtain the analytical expression for the Kraus decomposition of the quantum map of an environment modeled by an arbitrary quadratic fermionic Hamiltonian acting on one or two qubits, and derive simple functions to check the non-positivity of the intermediate map. These functions correspond to two different sufficient criteria for non-Markovianity. In the particular case of an environment represented by the Ising Hamiltonian, we discuss the two sources of non-Markovianity in the model, one due to the finite size of the lattice, and another due to the kind of interactions.Comment: 11 pages, 10 figure

Avaliação de Aspectos Psicogenéticos do Nível de Análise Heurística de Crianças por Meio do Jogo LIG-4

Esta pesquisa investigou, em uma abordagem psicogenética, aspectos do funcionamento cognitivo de crianças por meio de um jogo regras com base na teoria de Piaget. Participaram do estudo 21 crianças, de ambos os sexos, com idades de oito e doze anos, de uma escola pública de Ensino Fundamental de Vitória-ES. A coleta de dados ocorreu em três encontros por dupla, utilizando-se como instrumento o jogo Lig-4 e um protocolo contendo questões e situações-problema. O primeiro encontro foi realizado em duas etapas: uma de aprendizagem e outra de prática do jogo. O segundo em dois momentos, sendo um destinado à prática do jogo e outro à primeira avaliação do nível de análise heurística. No terceiro realizou-se a prática do jogo e a segunda avaliação do nível de análise heurística. Os dados foram analisados por meio de níveis de análise heurística formulados em relação aos Sistemas Cognitivos I e II propostos por Piaget. Entre os resultados, verificou-se que a situação destinada à primeira avaliação e a ampliação da prática do jogo, não possibilitaram uma melhora expressiva no nível de análise heurística dos participantes de ambas as idades na segunda avaliação. No entanto, comparando-se o desempenho das crianças das duas idades, constatou-se que o das de doze anos foi superior ao das de oito anos, sendo que no Sistema Cognitivo I elas alcançaram níveis mais complexos do que no Sistema Cognitivo II. Conclui-se que o jogo Lig-4 mostrou-se adequado para a análise de Sistemas Cognitivos, fornecendo subsídios para trabalhos de avaliação e intervenção

Nature of the constant factor in the relation between radial breathing mode frequency and tube diameter for single-wall carbon nanotubes

Resonance Raman scattering is used to determine the radial breathing mode (RBM) frequency (ωRBM) dependence on tube diameter (dt) for single-wall carbon nanotubes (SWNTs). We establish experimentally the ωRBM=227.0/dt as the fundamental relation for pristine SWNTs. All the other RBM values found in the literature can be explained by an upshift in frequency due mostly to van der Waals interaction between SWNTs and environment

Changes in hematological and biochemical parameters of tambaqui (Colossoma macropomum) parasitized by metazoan species.

The aim of this study was to evaluate the impacts of metazoan parasites on hematological and biochemical parameters and relative condition factor of tambaqui (Colossoma macropomum) farmed in northern Brazil. A total of 32 juvenile fish were captured from a commercial fish farm located in the municipality of Rio Preto da Eva, Amazonas state, Brazil. Parasite prevalence was 100% for Anacanthorus spathulatus, Mymarothecium boegeri and Notozothecium janauachensis, 100% for Neoechinorhynchus buttnerae and 53.13% for Dolops geayi. The greatest mean parasite intensity was found in acantocephalans followed by monogeneans and branchiuran crustaceans. A negative correlation was observed between abundance of N. buttnerae and hematocrit percentage, hemoglobin concentration, total thrombocyte count and glucose and between abundance of the monogenean and glucose concentration. Parasitic infections caused damage in tambaqui in terms of the observed hematological parameters that were characterized by hypochromic anemia and thrombocytopenia, which are important parameters to be used in parasitic diagnosis. This study is the first record of the occurrence of Dolops geayi in farmed tambaqui in the Amazon

Myxobolus sp. (Myxozoa) in the circulating blood of Colossoma macropomum (Osteichthyes, Characidae).

Myxosporea parasitize many organs in fresh and saltwater fish. Species of the genus Myxobolus parasitizing the gills and other organs of the tambaqui Colossoma macropomum have been described. In the present study, blood smears were made from juvenile tambaqui and were stained with May Grunwald-Giemsa-Wright in order to identify myxozoan parasites. Out of a total of 36 fish examined, one specimen (2.7%) that was reared in a cage presented spores that were identified as M. colossomatis, whereas fish kept in 250 L tanks showed prevalence of 5.5%. This is the first report of M. colossomatis in the blood of farmed tambaqui in the Amazon region. These results indicate that myxozoan parasites should also be investigated in fish blood smears. Some myxosporean species may cause diseases in fish, and these species need to be identified so that adequate preventive sanitary control can be instituted