Mobilizing agro-biodiversity and social networks to cope with adverse effects of climate and social changes: experiences from Kitui, Kenya

Poster presented at 13th Congress of the International Society of Ethnobiology. Montpellier (France), 20-25 May 201

Cancellation exponent and multifractal structure in two-dimensional magnetohydrodynamics: direct numerical simulations and Lagrangian averaged modeling

We present direct numerical simulations and Lagrangian averaged (also known as alpha-model) simulations of forced and free decaying magnetohydrodynamic turbulence in two dimensions. The statistics of sign cancellations of the current at small scales is studied using both the cancellation exponent and the fractal dimension of the structures. The alpha-model is found to have the same scaling behavior between positive and negative contributions as the direct numerical simulations. The alpha-model is also able to reproduce the time evolution of these quantities in free decaying turbulence. At large Reynolds numbers, an independence of the cancellation exponent with the Reynolds numbers is observed.Comment: Finite size box effects have been taken into account in the definition of the partition function. This has resulted in a more clear scaling in all figures. Several points are clarified in the tex

Pseudo-diffusive magnetotransport in graphene

Transport properties through wide and short ballistic graphene junctions are studied in the presence of arbitrary dopings and magnetic fields. No dependence on the magnetic field is observed at the Dirac point for any current cumulant, just as in a classical diffusive system, both in normal-graphene-normal and normal-graphene-superconductor junctions. This pseudo-diffusive regime is however extremely fragile respect to doping at finite fields. We identify the crossovers to a field-suppressed and a normal ballistic transport regime in the magnetic field - doping parameter space, and provide a physical interpretation of the phase diagram. Remarkably, pseudo-diffusive transport is recovered away from the Dirac point in resonance with Landau levels at high magnetic fields.Comment: 4+ pages, 2 figures. Minor corrections. Published version

"Las vías de lo legítimo": Derecho natural y estado católico en la obra de Clemente de Jesús Munguía

Este ensayo busca reinterpretar la respuesta eclesiástica a la reforma liberal mexicana a partir de una nueva lectura de la obra del obispo de Michoacán, Clemente de Jesús Munguía (1810-1868), quien fuera uno de los más agudos y polémicos defensores de la Iglesia mexicana en este período y a quien puede considerarse como uno de los constructores de la ilustración católica mexicana.This essay offers a new interpretation to the ecclesiastical response to the Mexican liberal reform, basaed on a new reading of Bishop, Clemente de Jesús Munguía's works. A fine exponent of the Mexican Catholic Enlightenment, Munguía (1810-1868) was one of the most insightful emd controversicü defenders of the Church during that troubled period.Publicad

State-of-the-art techniques for calculating spectral functions in models for correlated materials

The dynamical mean field theory (DMFT) has become a standard technique for the study of strongly correlated models and materials overcoming some of the limitations of density functional approaches based on local approximations. An important step in this method involves the calculation of response functions of a multiorbital impurity problem which is related to the original model. Recently there has been considerable progress in the development of techniques based on the density matrix renormalization group (DMRG) and related matrix product states (MPS) implying a substantial improvement to previous methods. In this article we review some of the standard algorithms and compare them to the newly developed techniques, showing examples for the particular case of the half-filled two-band Hubbard model.Comment: 8 pages, 4 figures, to be published in EPL Perspective