Why are massive O-rich AGB stars in our Galaxy not S-stars?

We present the main results derived from a chemical analysis carried out on a large sample of galactic O-rich AGB stars using high resolution optical spectroscopy (R~40,000-50,000) with the intention of studying their lithium abundances and/or possible s-process element enrichment. Our chemical analysis shows that some stars are lithium overabundant while others are not. The observed lithium overabundances are interpreted as a clear signature of the activation of the so-called ``Hot Bottom Burning'' (HBB) process in massive galactic O-rich AGB stars, as predicted by the models. However, these stars do not show the zirconium enhancement (taken as a representative for the s-process element enrichment) associated to the third dredge-up phase following thermal pulses. Our results suggest that the more massive O-rich AGB stars in our Galaxy behave differently from those in the Magellanic Clouds, which are both Li- and s-process-rich (S-type stars). Reasons for this unexpected result are discussed. We conclude that metallicity is probably the main responsible for the differences observed and suggest that it may play a more important role than generally assumed in the chemical evolution of AGB stars.Comment: 4 pages, 2 figures, to appear in the proceedings of the conference "Planetary Nebulae as astronomical tools" held in Gdansk, Poland, jun 28/jul 02, 200

Out-of-plane in situ cyclic testing of unreinforced stone masonry walls with distributed loads

The present paper reports an in situ experimental test campaign carried out on existing buildings, in order to investigate the seismic behaviour of traditional masonry walls subject to out-of-plane loads. For the testing proposes, an experimental test setup based on a selfequilibrated scheme was developed and optimized to be applied in situ in two specimens on original and strengthened conditions. The obtained results are presented and carefully discussed namely from the reinforcement solutions’ efficiency point-of-view, as well as compared to previous experimental data obtained for the same type of masonry walls. Additionally, a simplified linearized displacement-based procedure was adapted in order to characterize the nonlinear force-displacement relationship for unreinforced traditional masonry walls and to analytically predict the experimental test results. The confrontation between the experimental and the analytical results are presented and discussed

Overview of charmonium decays and production from Non-Relativistic QCD

I briefly review Non-Relativistic QCD and related effective theories, and discuss applications to heavy quarkonium decay, and production in electron-positron colliders.Comment: 8 pages, Invited talk at Charm 2010, Oct. 21-24, IHEP, Beijin

Quantifying the intrinsic amount of fabrication disorder in photonic-crystal waveguides from optical far-field intensity measurements

Residual disorder due to fabrication imperfections has important impact in nanophotonics where it may degrade device performance by increasing radiation loss or spontaneously trap light by Anderson localization. We propose and demonstrate experimentally a method of quantifying the intrinsic amount of disorder in state-of-the-art photonic-crystal waveguides from far-field measurements of the Anderson-localized modes. This is achieved by comparing the spectral range that Anderson localization is observed to numerical simulations and the method offers sensitivity down to ~ 1 nm

Approximate solutions for the skyrmion

We reconsider the Euler-Lagrange equation for the Skyrme model in the hedgehog ansatz and study the analytical properties of the solitonic solution. In view of the lack of a closed form solution to the problem, we work on approximate analytical solutions. We show that Pade approximants are well suited to continue analytically the asymptotic representation obtained in terms of a power series expansion near the origin, obtaining explicit approximate solutions for the Skyrme equations. We improve the approximations by applying the 2-point Pade approximant procedure whereby the exact behaviour at spatial infinity is incorporated. An even better convergence to the exact solution is obtained by introducing a modified form for the approximants. The new representations share the same analytical properties with the exact solution at both small and large values of the radial variable r.Comment: 15 pages, 5 figures. 1 Reference adde