8,642 research outputs found
The teaching of Spanish in Maltese secondary schools : an overview of the current state and needs
This contribution looks at the teaching of Spanish in Maltese secondary schools. However, before looking more closely at its establishment and development in Malta, it is probably desirable that we review the growth of Spanish in the world. In this manner we will be in a position to better understand the specific context of the teaching of Spanish in Forms IV and V in Maltese secondary schools.peer-reviewe
Magnetism and topological phases in an interacting decorated honeycomb lattice with spin-orbit coupling
We study the interplay between spin-orbit coupling (SOC) and Coulomb
repulsion in a Hubbard model on a decorated honeycomb lattice which leads to a
plethora of phases. While a quantum spin hall insulator is stable at weak
Coulomb repulsion and moderate SOC, a semimetallic phase emerges at large SOC
in a broad range of Coulomb repulsion. This semimetallic phase has topological
properties not observed in conventional metals such as a finite, non-quantized
spin Hall conductivity. At large Coulomb repulsion and negligible spin-orbit
coupling, electronic correlations stabilize a resonance valence bond (RVB) spin
liquid state in contrast to the classical antiferromagnetic state predicted by
mean-field theory. Under sufficiently strong SOC, such RVB state is transformed
into a magnetic insulator consisting on S~3/2 localized moments on a honeycomb
lattice with antiferromagnetic order and topological features.Comment: 13 pages, 10 figure
The mean-variance model from the inverse of the variance-covariance matrix
In this paper we obtain the main results of the Markowitz mean-variance model from the inverse of the covariance matrix, following a shorter and mathematically rigorous path. We also obtain the equilibrium expression of Sharpes capital asset pricing model (CAPM).capm, beta, portfolio composition
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