Stellar archeology of the nearby LINER galaxies NGC 4579 and NGC 4736

Stellar archeology of nearby LINER galaxies may reveal if there is a stellar young population that may be responsible for the LINER phenomenon. We show results for the classical LINER galaxies NGC 4579 and NGC 4736 and find no evidence of such populations.Comment: 2 pages, 2 figures, to be published in the Proceedings of the IAU Symposium no. 26

The use of genes for performance enhancement: doping or therapy?

Recent biotechnological advances have permitted the manipulation of genetic sequences to treat several diseases in a process called gene therapy. However, the advance of gene therapy has opened the door to the possibility of using genetic manipulation (GM) to enhance athletic performance. In such ‘gene doping’, exogenous genetic sequences are inserted into a specific tissue, altering cellular gene activity or leading to the expression of a protein product. The exogenous genes most likely to be utilized for gene doping include erythropoietin (EPO), vascular endothelial growth factor (VEGF), insulin-like growth factor type 1 (IGF-1), myostatin antagonists, and endorphin. However, many other genes could also be used, such as those involved in glucose metabolic pathways. Because gene doping would be very difficult to detect, it is inherently very attractive for those involved in sports who are prepared to cheat. Moreover, the field of gene therapy is constantly and rapidly progressing, and this is likely to generate many new possibilities for gene doping. Thus, as part of the general fight against all forms of doping, it will be necessary to develop and continually improve means of detecting exogenous gene sequences (or their products) in athletes. Nevertheless, some bioethicists have argued for a liberal approach to gene doping

Mapping low and high density clouds in astrophysical nebulae by imaging forbidden line emission

Emission line ratios have been essential for determining physical parameters such as gas temperature and density in astrophysical gaseous nebulae. With the advent of panoramic spectroscopic devices, images of regions with emission lines related to these physical parameters can, in principle, also be produced. We show that, with observations from modern instruments, it is possible to transform images taken from density sensitive forbidden lines into images of emission from high and low-density clouds by applying a transformation matrix. In order to achieve this, images of the pairs of density sensitive lines as well as the adjacent continuum have to be observed and combined. We have computed the critical densities for a series of pairs of lines in the infrared, optical, ultraviolet and X-rays bands, and calculated the pair line intensity ratios in the high and low-density limit using a 4 and 5 level atom approximation. In order to illustrate the method we applied it to GMOS-IFU data of two galactic nuclei. We conclude that this method provides new information of astrophysical interest, especially for mapping low and high-density clouds; for this reason we call it "the ld/hd imaging method".Comment: 7 pages, 4 figures, accepted for publication on MNRA

PCA Tomography and its application to nearby galactic nuclei

With the development of modern technologies such as IFUs, it is possible to obtain data cubes in which one produces images with spectral resolution. To extract information from them can be quite complex, and hence the development of new methods of data analysis is desirable. We briefly describe a method of analysis of data cubes (data from single field observations, containing two spatial and one spectral dimension) that uses Principal Component Analysis (PCA) to express the data in the form of reduced dimensionality, facilitating efficient information extraction from very large data sets. We applied the method, for illustration purpose, to the central region of the low ionization nuclear emission region (LINER) galaxy NGC 4736, and demonstrate that it has a type 1 active nucleus, not known before. Furthermore, we show that it is displaced from the centre of its stellar bulge.Comment: 4 pages, 1 figure, 1 table, to be published in the Proceedings of the IAU Symposium no. 26

Acesso aberto à informação de solos brasileiros.

O objetivo deste trabalho foi demonstrar as formas de acesso aos dados e as etapas para a realização de consultas públicas, via Internet.CIIC 2014. Nº 14605

The contact process in disordered and periodic binary two-dimensional lattices

The critical behavior of the contact process in disordered and periodic binary 2d-lattices is investigated numerically by means of Monte Carlo simulations as well as via an analytical approximation and standard mean field theory. Phase-separation lines calculated numerically are found to agree well with analytical predictions around the homogeneous point. For the disordered case, values of static scaling exponents obtained via quasi-stationary simulations are found to change with disorder strength. In particular, the finite-size scaling exponent of the density of infected sites approaches a value consistent with the existence of an infinite-randomness fixed point as conjectured before for the 2d disordered CP. At the same time, both dynamical and static scaling exponents are found to coincide with the values established for the homogeneous case thus confirming that the contact process in a heterogeneous environment belongs to the directed percolation universality class.Comment: submitted to Physical Review