Light radioactive nuclei capture reactions with phenomenological potential models

Light radioactive nuclei play an important role in many astrophysical environments. Due to very low cross sections of some neutron and proton capture reactions by these radioactive nuclei at energies of astrophysical interest, direct laboratory measurements are very difficult. For radioactive nuclei such as 8Li and 8B, the direct measurement of neutron capture reactions is impossible. Indirect methods have been applied to overcome these difficulties. In this work we will report on the results and discussion of phenomenological potential models used to determine some proton and neutron capture reactions. As a test we show the results for the 16O(p,g)17F_gs(5/2+) and 16O(p,g)17F_ex(1/2+) capture reactions.We also computed the nucleosynthesis cross sections for the 7Li(n,g)8Li, 8Li(n,g)9Li and 8B(p,g)9C capture reactions.Comment: Invited talk at Nuclear Physics Meeting in Brazil (2009). To be published at AIP conference proceeding

Research Notes on the Emerging Concepts of Digital Heritage in Brazil

This paper presents the first results in our investigation of the emerging Digital Heritage concepts in Brazil. It focuses on the analysis of a government experience with social media intended to prepare an official report on digital culture. We found that this report follows the Unesco guidelines in general, but falls short in the discussion of so-called born-digital heritage. Our hypothesis is that this omission is due to the lack of relevant web-archiving initiatives in Brazil.\ud \u

A Simple Feasible Alternative Procedure to Estimate Models with High-Dimensional Fixed Effects

In this paper we describe an alternative iterative approach for the estimation of linear regression models with high-dimensional fixed-effects such as large employer-employee data sets. This approach is computationally intensive but imposes minimum memory requirements. We also show that the approach can be extended to non-linear models and potentially to more than two high dimensional fixed effects.high dimensional fixed effects, linked employer-employee data

A few remarks on the zero modes of the Faddeev-Popov operator in the Landau and maximal Abelian gauges

The construction outlined by Henyey is employed to provide examples of normalizable zero modes of the Faddeev-Popov operator in the Landau and maximal Abelian gauges in SU(2) Euclidean Yang-Mills theories in d=3 dimensions. The corresponding gauge configurations have all finite norm ||A||^2 < \infty. In particular, in the case of the Landau gauge, the explicit construction of an infinite class of normalizable zero modes with finite norm ||A||^2 is provided.Comment: 9 pages. Extended discussion in the conclusions. Version accepted for publication in the J. Math. Phy

Risk and Wealth in a Model of Self-fulfilling Currency Crises

We analyze the effect of risk aversion, wealth and portfolios on the behavior of investors in a global game model of currency crises with continuous action choices. The model generates a rich set of striking theoretical predictions. For example, risk aversion makes currency crises significantly less likely; increased wealth makes crises more likely; and foreign direct investment (illiquid investments in the target currency) make crises more likely. Our results extend linearly to a heterogeneous agent population.Currency crisis, Sunspots, Global games, Risk aversion, Wealth, Portfolio