Portugueses Gaúchos: socio-political transnationalism, integration and identities in the River Plate Region

Através da análise de entrevistas com emigrantes portugueses e os seus descendentes na região platina, o artigo explora as relações entre integração e participação em associações de emigrantes, e como elas se inter-relacionam com a identidade colectiva na sociedade de recepção. Examinamos o papel das associações de emigrantes na construção e reforço dos símbolos, referências e identidades nacionais, e como simultaneamente facilitam a integração. Sugerimos que a activação de identidades do país de origem não tem efeitos etnicizantes; pelo contrário, funciona como recurso efectivo da integração, promovendo as redes sociais abertas

Strategies to increase austenite FCC relative phase stability in high-Mn steels

Several strategies to increase the FCC austenite stability compared to BCC and HCP martensites have been tested and are discussed. The relative stability of the different phases was analyzed by studying the effects of: a) grain size, b) antiferromagnetic ordering of the austenite, c) thermal cycling through the FCC-HCP transition, d) plastic deformation of the austenite and e) combined effects. As a first step, the effect of decreasing the grain size was analyzed in Fe-Mn alloys for Mn contents smaller than 18 wt.%, where BCC and HCP martensites compete in stability. Formation of the BCC phase is inhibited for 15 wt.% and 17 wt.% of Mn for grain sizes smaller than 2 μm. This enabled, for the first time at these compositions, the measurement of the Neel temperature of the austenite using specific heat and magnetic measurements. A comparison of the obtained transition temperatures with accepted models is discussed. The effect of modifying the grain size on the FCC-HCP transition temperatures was also analyzed for 15 wt.% and 17 wt.% Mn contents showing a complete HCP inhibition for grain sizes smaller than 200 nm. A nucleation model for the HCP martensite is considered which includes an additional resistance to the transformation term depending on the austenitic grain size. Additional combined effects on the FCC stabilization are discussed like the interaction between the antiferromagnetic ordering and the introduction of defects by thermal cycling through the martensitic transformation. The analysis can be easily applied to systems with a larger number of components. Results obtained in the Fe-Mn-Cr system are also presented.The authors acknowledge the financial support from ANPCyT (PICT-2017-2198), CONICET (PIP 2015-112-201501-00521), CONICET (PIP 2017e2019 GI 0634), ANPCyT (PICT-2017-4518), and Universidad Nacional de Cuyo (06/C516 and 06/C588)

Analyticity and uniform stability in the inverse spectral problem for Dirac operators

We prove that the inverse spectral mapping reconstructing the square integrable potentials on [0,1] of Dirac operators in the AKNS form from their spectral data (two spectra or one spectrum and the corresponding norming constants) is analytic and uniformly stable in a certain sense.Comment: 19 page