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A case in favor of the
Using an interaction extracted from the local hidden gauge Lagrangians, which
brings together vector and pseudoscalar mesons, and the coupled channels (s-wave), (d-wave), (s-wave) and (d-wave),
we look in the region of MeV and we find two resonances
dynamically generated by the interaction of these channels, which are naturally
associated to the and . The appears neatly as a pole in the complex plane. The free parameters of
the theory are chosen to fit the (d-wave) data. Both the real and
imaginary parts of the amplitude vanish in our approach in the vicinity
of this resonance, similarly to what happens in experimental determinations,
what makes this signal very weak in this channel. This feature could explain
why this resonance does not show up in some experimental analyses, but the
situation is analogous to that of the resonance, the second scalar
meson after the in the (d-wave) amplitude. The
unitary coupled channel approach followed here, in connection with the
experimental data, leads automatically to a pole in the 1700 MeV region and
makes this second resonance unavoidable
Phylogenetic Relationships and Character Evolution of the Neotropical Butterfly Genus Hamadryas (Nymphalidae: Biblidinae)
The butterflies in the genus Hamadryas are popular and noticeable representatives of the Neotropical Lepidoptera fauna. After a thorough taxonomic revision, 20 species were acknowledged within the genus, however no hypothesis of their phylogenetic relationship was proposed. The present dissertation provides a step further into the understanding of this fascinating group of butterflies not only by proposing the first phylogenetic hypothesis for the genus based on morphological and molecular data, but also by exploring for the first time in a group of butterflies the potential effect of venation associated with an specific behaviour on wing shape. Furthermore, this dissertation provides testable evolutionary hypotheses about the pattern of change for some of their most interesting natural history characters such as sound production and sexual dimorphism. The dissertation is organized in three chapters that can be visualized as manuscripts ready for publication; the first of these being already published (Garzón-Orduña, 2012)
Inversion of stellar statistics equation for the Galactic Bulge
A method based on Lucy (1974, AJ 79, 745) iterative algorithm is developed to
invert the equation of stellar statistics for the Galactic bulge and is then
applied to the K-band star counts from the Two-Micron Galactic Survey in a
number of off-plane regions (10 deg.>|b|>2 deg., |l|<15 deg.).
The top end of the K-band luminosity function is derived and the morphology
of the stellar density function is fitted to triaxial ellipsoids, assuming a
non-variable luminosity function within the bulge. The results, which have
already been outlined by Lopez-Corredoira et al.(1997, MNRAS 292, L15), are
shown in this paper with a full explanation of the steps of the inversion: the
luminosity function shows a sharp decrease brighter than M_K=-8.0 mag when
compared with the disc population; the bulge fits triaxial ellipsoids with the
major axis in the Galactic plane at an angle with the line of sight to the
Galactic centre of 12 deg. in the first quadrant; the axial ratios are
1:0.54:0.33, and the distance of the Sun from the centre of the triaxial
ellipsoid is 7860 pc. The major-minor axial ratio of the ellipsoids is found
not to be constant. However, the interpretation of this is controversial. An
eccentricity of the true density-ellipsoid gradient and a population gradient
are two possible explanations.
The best fit for the stellar density, for 1300 pc<t<3000 pc, are calculated
for both cases, assuming an ellipsoidal distribution with constant axial
ratios, and when K_z is allowed to vary. From these, the total number of bulge
stars is ~ 3 10^{10} or ~ 4 10^{10}, respectively.Comment: 19 pages, 23 figures, accepted in MNRA
Analysis of the microstructure of Cosmic Ray air showers using the HADES RPC ToF wall detectors
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