A Second Shell in the Fornax dSph Galaxy

In the search for tidal structure in Galactic satellite systems, we have conducted a photometric survey over a 10 square degree area centred on the Fornax dSph galaxy. The survey was made in two colours, and the resulting colour-magnitude data were used as a mask to select candidate Fornax RGB stars, thereby increasing the contrast of Fornax stars to background sources in the outer regions. Previously, we reported the presence of a shell (age 2 Gyr) located towards the centre of Fornax. In this contribution we reveal a second shell, significantly larger than the first, located 1.3 degrees NW from the centre of Fornax, outside the nominal tidal radius. Moreover, the distribution of Fornax RGB stars reveals two lobes extending to the spatial limit of our survey, and aligned with the minor axis and with the two shells. These results support the hypothesis of a merger between Fornax and a gas-rich companion approximately 2 Gyr ago.Comment: Four pages,accepted for the Publications of the Astronomical Society of Australia. Contribution the annual ASA meeting, Brisbane 200

Finding RR Lyrae Stars with SkyMapper: an Observational Test

One of the major science goals of the SkyMapper Survey of the Southern Hemisphere sky is the determination of the shape and extent of the halo of the Galaxy. In this paper we quantify the likely efficiency and completeness of the survey as regards the detection of RR Lyrae variable stars, which are excellent tracers of the halo stellar population. We have accomplished this via observations of the RR Lyrae-rich globular cluster NGC 3201. We find that for single epoch uvgri observations followed by two further epochs of g, r imaging, as per the intended three-epoch survey strategy, we recover known RR Lyraes with a completeness exceeding 90%. We also investigate boundaries in the gravity-sensitive single-epoch two-color diagram that yield high completeness and high efficiency (i.e., minimal contamination by non-RR Lyraes) and the general usefulness of this diagram in separating populations.Comment: 10 pages, 5 figures, to appear in the Publications of the Astronomical Society of Australia (PASA), published by Cambridge University Pres

A segurança de produtos hortifrutícolas frescos.

A importância da segurança e da qualidade dos produtos hortifrutícolas frescos no agronegócio; Os alimentos e a saúde do consumidor; Riscos à segurança de frutas e hortaliças frescas; Atributos de qualidade e deterioração; Controle de qualidade e rastreabilidade.bitstream/CPATSA/26936/1/SDC181.pd

Characterizing neuromorphologic alterations with additive shape functionals

The complexity of a neuronal cell shape is known to be related to its function. Specifically, among other indicators, a decreased complexity in the dendritic trees of cortical pyramidal neurons has been associated with mental retardation. In this paper we develop a procedure to address the characterization of morphological changes induced in cultured neurons by over-expressing a gene involved in mental retardation. Measures associated with the multiscale connectivity, an additive image functional, are found to give a reasonable separation criterion between two categories of cells. One category consists of a control group and two transfected groups of neurons, and the other, a class of cat ganglionary cells. The reported framework also identified a trend towards lower complexity in one of the transfected groups. Such results establish the suggested measures as an effective descriptors of cell shape

Reduction and construction of Poisson quasi-Nijenhuis manifolds with background

We extend the Falceto-Zambon version of Marsden-Ratiu Poisson reduction to Poisson quasi-Nijenhuis structures with background on manifolds. We define gauge transformations of Poisson quasi-Nijenhuis structures with background, study some of their properties and show that they are compatible with reduction procedure. We use gauge transformations to construct Poisson quasi-Nijenhuis structures with background.Comment: to appear in IJGMM

The Power Spectrum of Galaxies in the Nearby Universe

We compute the power spectrum of galaxy density fluctuations in a recently completed redshift survey of optically-selected galaxies in the southern hemisphere (SSRS2). The amplitude and shape of the SSRS2 power spectrum are consistent with results of the Center for Astrophysics redshift survey of the northern hemisphere (CfA2), including the abrupt change of slope on a scale of 30-50Mpc/h; these results are reproducible for independent volumes of space and variations are consistent with the errors estimated from mock surveys. Taken together, the SSRS2 and CfA2 form a complete sample of 14,383 galaxies which covers one-third of the sky. The power spectrum of this larger sample continues to rise on scales up to ~ 200Mpc/h, with weak evidence for flattening on the largest scales. The SSRS2+CfA2 power spectrum and the power spectrum constraints implied by COBE are well-matched by an Omega*h ~ 0.2, Omega+lambda_0=1 CDM model with minimal biasing of optically-selected galaxies.Comment: Accepted for publication in The Astrophysical Journal Letters, Sept. 23, 1994. 10 pages uuencoded compressed postscript, including two figures. JHU-9410200