Contact interaction in an unitary ultracold Fermi gas

An ultracold Fermi atomic gas at unitarity presents universal properties that in the diluted limit can be well described by a contact interaction. By employing a guide function with correct boundary conditions and making simple modifications to the sampling procedure we are able to handle for the first time a true contact interaction in a quantum Monte Carlo calculation. The results are obtained with small variances. Our calculations for the Bertsch and contact parameters are in excellent agreement with published experiments. The possibility of using a more faithfully description of ultracold atomic gases can help uncover features yet unknown of the ultracold atomic gases. In addition, this work paves the way to perform quantum Monte Carlo calculations for systems interacting with contact interactions, where in many cases the description using potentials with finite effective range might not be accurate

Simposio: investigações em formação de professores de ciências: olhares que se complementam

Apresentaremos investigações sobre formação de professores de Ciências realizadas na Argentina, México e Brasil. Tricárico et al.procuraram revelar a aprendizagem em Ciências e os modelos didáticos utilizados pelos docentes. Gallegos e Bonilla investigaram as correlações entre as concepções sobre a natureza e a aprendizagem de ciências de um grupo de professores e suas práticas docentes. Sasseron relata uma investigação em que procura analisar a argumentação entre alunos e professora focalizando o modo como esta é construída e os elementos que a constituem. Pessoa relata a parceria entre a universidade e escola onde pesquisa as estratégias de ensino e as habilidades das professoras no desenvolvimento de competências científicas

Differential H4K16ac levels ensure a balance between quiescence and activation in hematopoietic stem cells

Hematopoietic stem cells (HSCs) are able to reconstitute the bone marrow while retaining their self-renewal property. Individual HSCs demonstrate heterogeneity in their repopulating capacities. Here, we found that the levels of the histone acetyltransferase MOF (males absent on the first) and its target modification histone H4 lysine 16 acetylation are heterogeneous among HSCs and influence their proliferation capacities. The increased proliferative capacities of MOF-depleted cells are linked to their expression of CD93. The CD93+ HSC subpopulation simultaneously shows transcriptional features of quiescent HSCs and functional features of active HSCs. CD93+ HSCs were expanded and exhibited an enhanced proliferative advantage in Mof+/− animals reminiscent of a premalignant state. Accordingly, low MOF and high CD93 levels correlate with poor survival and increased proliferation capacity in leukemia. Collectively, our study indicates H4K16ac as an important determinant for HSC heterogeneity, which is linked to the onset of monocytic disorders