Systematic evolution of the magnetotransport properties of Bi_{2}Sr_{2-x}La_{x}CuO_{6} in a wide doping range

Recently we have succeeded in growing a series of high-quality Bi_{2}Sr_{2-x}La_{x}CuO_{6} crystals in a wide range of carrier concentrations. The data of \rho_{ab}(T) and R_H(T) of those crystals show behaviors that are considered to be "canonical" to the cuprates. The optimum zero-resistance T_c has been raised to as high as 38 K, which is almost equal to the optimum T_c of La_{2-x}Sr_{x}CuO_{4}.Comment: 2 pages, 2 figures, to be published in Physics C (Proceedings of the International Conference on Materials and Mechanisms of Superconductivity, High Temperature Superconductors VI (M2S-HTSC-VI), Houston, Feb 20-25, 2000

Stripes and Charge Transport Properties of High-T_c Cuprates

Unusual features in the in-plane charge transport in lightly hole-doped La_{2-x}Sr_{x}CuO_{4} single crystals are described. Notably, both the in-plane resistivity and the Hall coefficient show a metallic behavior at moderate temperatures even in the long-range-ordered antiferromagnetic phase, which obviously violates the Mott-Ioffe-Regel criterion for the metallic transport and can hardly be understood without employing the role of charge stripes. Moreover, the mobility of holes in this "metallic" antiferromagnetic state is found to be virtually the same as that in optimally-doped crystals, which strongly suggests that the stripes govern the charge transport in a surprisingly wide doping range up to optimum doping.Comment: Invited paper at ICTP Workshop on Intrinsic Multiscale Structure and Dynamics in Complex Electronic Oxides, Trieste, July 2002. (To be published in the Proceedings of the ICTP Workshop as a World Scientific book.) Some statements are revised and references are added in response to the comments from theorist friend

Mixed quantal-semiquantal dynamics with stochastic particles for backreaction

A mixed quantal-semiquantal theory is presented in which the semiquantal squeezed-state wave packet describes the heavy degrees of freedom. We first derive mean-field equations of motion from the time-dependent variational principle. Then, in order to take into account the interparticle correlation, in particular the 'quantum backreaction' beyond the mean-field approximation, we introduce the stochastic particle description for both the quantal and semiquantal parts. A numerical application on a model of O2 scattering from a Pt surface demonstrates that the proposed scheme gives correct asymptotic behavior of the scattering probability, with improvement over the mixed quantum-classical scheme with Bohmian particles, which is comprehended by comparing the Bohmian and the stochastic trajectories.Comment: 4 pages, 2 figure

Girls and the Media: Girlhood Studies Agenda and Prospects in Italy

Within the Italian context, girlhood studies can hardly be considered a specific field: adolescence and gender construction in Italy have historically been investigated by sociology and psychology, although, in recent years, media studies have also focused on youth media consumption as a cultural process in the broader sense, investigating the relevance of the media in the identity-building process. Actually, the lack of a definition of girlhood studies as such did not prevent Italian research from providing theoretical contributions and significant research on girlhood, mostly in the fields of reception studies, audience studies and textual analysis. On these premises, the article aims at discussing the relationships between girlhood and the media nowadays, keeping in mind firstly the recent transformations in media consumption within the networked society; secondly the coexistence of contradictory representations of girlhood in both the local and the global and the way it is assembled in the young audience discourse; and thirdly the phenomenon of identity co-creation in creative fandom practices.Within the Italian context, girlhood studies can hardly be considered a specific field: adolescence and gender construction in Italy have historically been investigated by sociology and psychology, although, in recent years, media studies have also focused on youth media consumption as a cultural process in the broader sense, investigating the relevance of the media in the identity-building process. Actually, the lack of a definition of girlhood studies as such did not prevent Italian research from providing theoretical contributions and significant research on girlhood, mostly in the fields of reception studies, audience studies and textual analysis. On these premises, the article aims at discussing the relationships between girlhood and the media nowadays, keeping in mind firstly the recent transformations in media consumption within the networked society; secondly the coexistence of contradictory representations of girlhood in both the local and the global and the way it is assembled in the young audience discourse; and thirdly the phenomenon of identity co-creation in creative fandom practices