4,006 research outputs found
GG Tau: the fifth element
We aim at unveiling the observational imprint of physical mechanisms that
govern planetary formation in young, multiple systems. In particular, we
investigate the impact of tidal truncation on the inner circumstellar disks. We
observed the emblematic system GG Tau at high-angular resolution: a
hierarchical quadruple system composed of low-mass T Tauri binary stars
surrounded by a well-studied, massive circumbinary disk in Keplerian rotation.
We used the near-IR 4-telescope combiner PIONIER on the VLTI and
sparse-aperture-masking techniques on VLT/NaCo to probe this proto-planetary
system at sub-AU scales. We report the discovery of a significant closure-phase
signal in H and Ks bands that can be reproduced with an additional low-mass
companion orbiting GG Tau Ab, at a (projected) separation rho = 31.7 +/- 0.2mas
(4.4 au) and PA = 219.6 +/- 0.3deg. This finding offers a simple explanation
for several key questions in this system, including the missing-stellar-mass
problem and the asymmetry of continuum emission from the inner dust disks
observed at millimeter wavelengths. Composed of now five co-eval stars with
0.02 <= Mstar <= 0.7 Msun, the quintuple system GG Tau has become an ideal test
case to constrain stellar evolution models at young ages (few 10^6yr).Comment: 5pages, 3 figures, 1 appendix (online material
An automated system for chromosome analysis. Volume 1: Goals, system design, and performance
The design, construction, and testing of a complete system to produce karyotypes and chromosome measurement data from human blood samples, and a basis for statistical analysis of quantitative chromosome measurement data is described. The prototype was assembled, tested, and evaluated on clinical material and thoroughly documented
An Automated System for Chromosome Analysis
The design, construction, and testing of a complete system to produce karyotypes and chromosome measurement data from human blood samples, and to provide a basis for statistical analysis of quantitative chromosome measurement data are described
Design of highly stabilized nanocomposite inks based on biodegradable polymer-matrix and gold nanoparticles for Inkjet Printing
Nowadays there is a worldwide growing interest in the Inkjet Printing technology owing to its potentially high levels of geometrical complexity, personalization and resolution. There is also social concern about usage, disposal and accumulation of plastic materials. In this work, it is shown that sugar-based biodegradable polyurethane polymers exhibit outstanding properties as polymer-matrix for gold nanoparticles composites. These materials could reach exceptional stabilization levels, and demonstrated potential as novel robust inks for Inkjet based Printing. Furthermore, a physical comparison among different polymers is discussed based on stability and printability experiments to search for the best ink candidate. The University of Seville logo was printed by employing those inks, and the presence of gold was confirmed by ToF-SIMS. This approach has the potential to open new routes and applications for fabrication of enhanced biomedical nanometallic-sensors using stabilized AuNP.Spanish Ministerio de Economía y Competitividad MINECO, (Grants Nos. CTQ2016- 78703-P and MAT2016-78703-P)Junta de Andalucía (Consolidation Grant for Research Group FQM135 and 2017/FQM-386, P-2018/809)University of Seville (V y VI Plan Propio PP2016-5937
Synthetic aperture radar/LANDSAT MSS image registration
Algorithms and procedures necessary to merge aircraft synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) imagery were determined. The design of a SAR/LANDSAT data merging system was developed. Aircraft SAR images were registered to the corresponding LANDSAT MSS scenes and were the subject of experimental investigations. Results indicate that the registration of SAR imagery with LANDSAT MSS imagery is feasible from a technical viewpoint, and useful from an information-content viewpoint
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