Contributions to the Experimental Pathology of the Stomach: I. Experimental Pyloric Stenosis

n/

Apontamentos sobre o ensino de Ciências nas séries escolares iniciais

Science education, and education in general, must be improved in Brazil. Management of school systems is deficient. Teacher training is inadequate and insufficient. Curricula and classroom methodology should be brought up to date. Science should be taught, based on inquiry, since the first school grades. Science popularization in museums and science centers and in the media can be an important teaching resource.O ensino de Ciências, assim com a educação em geral, precisa ser aperfeiçoa-do no Brasil. A gestão das redes escolares é deficiente. A formação de professores é inadequada e insuficiente. Os currículos e a metodologia em sala de aula precisam ser atualizados. As ciências podem e devem ser ensinadas, baseadas em investigação, desde as primeiras séries escolares. A divulgação científica em museus e centros de ciência e nos meios de comunicação pode ser um recurso importante para o ensino

The ErbB3 binding protein Ebp1 interacts with Sin3A to repress E2F1 and AR-mediated transcription

Ectopic expression of ebp1, a member of the PA2G4 family, inhibits the proliferation and induces the differentiation of human breast and prostate cancer cell lines. Ebp1 inhibits transcription of E2F1 and androgen receptor regulated genes such as prostate specific antigen (PSA) through its interactions with histone deacetylases (HDACs). To further understand Ebp1's interactions with other components of the transcriptional repression machinery, we examined the association of Ebp1 with the corepressor Sin3A. Ebp1 interacted with Sin3A both in vitro and in vivo as demonstrated by glutathione S-transferase (GST) pull-down and coimmunoprecipitation analysis. The C-terminal domain of Ebp1, responsible for its ability to repress transcription and arrest cell growth, was necessary and sufficient for binding Sin3A. The C-terminal domain of Sin3A, containing the paired amphipathic domain 4 and the HDAC interacting domain, bound Ebp1. Recombinant Sin3A bound Ebp1 directly, but recombinant HDAC2 failed to bind Ebp1. Chromatin immunoprecipitation (ChIP) and DNA affinity precipitation analysis demonstrated that Ebp1 and Sin3A associate at the PSA and E2F1 promoters. Functionally, Sin3A enhanced the ability of Ebp1 to repress transcription of androgen receptor (AR) and E2F1 regulated genes. These results demonstrate that Ebp1 participates in transcriptional regulation via its interaction with the Sin3–HDAC

Modulation of tumour colony growth by irradiated accessory cells.

The ability of human tumour cells to form colonies in soft agar is enhanced by the presence of autologous phagocytic/adherent cells. We investigated the effect of irradiation on the ability of the adherent cells to support human tumour colony formation. Relatively low doses of irradiation significantly increased the growth enhancing ability of adherent cells in 17/19 cases. The possibility that the enhancement was mediated by inactivation of radiosensitive contaminating lymphocytes was explored. Depletion of T lymphocytes from unirradiated adherent cells by a monoclonal antibody and complement resulted in little overall change in tumour colony growth. However, elimination of only the suppressor subset (OKT8+) of T lymphocytes resulted in increased colony growth relative to control values obtained with unirradiated adherent cells. In contrast, depletion of T lymphocytes from irradiated adherent cells by a pan T monoclonal antibody and complement decreased colony formation. Thus, the ability of irradiated macrophages to enhance tumour colony growth appeared to be mediated by a T lymphocyte. The effect of irradiation on isolated populations of macrophages and T lymphocytes was also examined. The enhanced ability of irradiated adherent cells to support tumor colony growth appeared to have been due to treatment of T lymphocytes alone. The results indicate that both adherent macrophages and lymphocytes may influence the growth of clonogenic human tumour cells

Reconstruction of thermally-symmetrized quantum autocorrelation functions from imaginary-time data

In this paper, I propose a technique for recovering quantum dynamical information from imaginary-time data via the resolution of a one-dimensional Hamburger moment problem. It is shown that the quantum autocorrelation functions are uniquely determined by and can be reconstructed from their sequence of derivatives at origin. A general class of reconstruction algorithms is then identified, according to Theorem 3. The technique is advocated as especially effective for a certain class of quantum problems in continuum space, for which only a few moments are necessary. For such problems, it is argued that the derivatives at origin can be evaluated by Monte Carlo simulations via estimators of finite variances in the limit of an infinite number of path variables. Finally, a maximum entropy inversion algorithm for the Hamburger moment problem is utilized to compute the quantum rate of reaction for a one-dimensional symmetric Eckart barrier.Comment: 15 pages, no figures, to appear in Phys. Rev.

Application of Global Positioning Measurements to Continental Collision in the Pamir-Tien Shan Region, Central Asia and GPS Survey of the Western Tien Shan

In this report, we summarize what we have accomplished with five years of funding from NASA under its DOSE program, and with a comparable level of funding from NSF. We describe the development of a GPS network in the Tien Shan of Kyrgyzstan and Kazakhstan of the former Soviet Union, the analysis of data, and the main results. This discussion presents the state of the current network, which has grown significantly since the termination of our DOSE grants, with continued support both from NSF through its continental dynamics program and from NASA's SENH program. Although grants from NASA's DOSE program did not support this growth not directly, it did so indirectly by building the infrastructure that has enabled further expansion in an area where otherwise there would be only a small GPS presence. We note how the network has grown over time, but the emphasis of this discussion is on the quantity and quality of measurements that we have made