Policies and regulations in Mexico with regard to genetic technology and food security

In 1988 the first application for field trials of a GMO was formally received in Mexico. Since then a Biosafety law, few bylaws and national official standards were enacted in order to regulate the safe use of GMOs and to evaluate, control and avoid adverse effects to human health and the environment. The Law on Biosafety of Genetically Modified Organisms was enacted in 2005 in order to comply with international obligations derived from the Cartagena Protocol on Biosafety signed by Mexico in 2000. This law established a biosafety legal framework to regulate the use of GMOs, protect biodiversity, and promote the conservation of organisms which Mexico is center of origin and center of genetic diversity. Since then, 561 permits for the release of GMOs into the environment have been granted between 2005 and 2014. This report gives and overview of the country’s approach to the use of GMOs, the current status of the biosafety legislation in Mexico and the development of policies and regulations since the first introduction of GM crops in the country

Initial data giving rise to naked singularities in spherically symmetric dust collapse

The phase space corresponding to a particular four-parameter family of initial data for the gravitational collapse of a spherically symmetric dust cloud is investigated. In a certain limit of the parameters, this family reproduces the case of homogenous mass density -constant mass distribution- and zero initial velocity, while in another limit, it generates a globally naked singularity. We show that for initial data characterizing flat density profiles, as well as large initial velocities, the probability of forming a globally naked singularity is low.Comment: 5 pages, 5 figures, prepared for the proceedings of the IX Workshop of the Gravitational and Mathematical Physics Division of the Mexican Physical Society. Refereed versio

An Exactly Solvable Phase-Field Theory of Dislocation Dynamics, Strain Hardening and Hysteresis in Ductile Single Crystals

An exactly solvable phase-field theory of dislocation dynamics, strain hardening and hysteresis in ductile single crystals is developed. The theory accounts for: an arbitrary number and arrangement of dislocation lines over a slip plane; the long-range elastic interactions between dislocation lines; the core structure of the dislocations resulting from a piecewise quadratic Peierls potential; the interaction between the dislocations and an applied resolved shear stress field; and the irreversible interactions with short-range obstacles and lattice friction, resulting in hardening, path dependency and hysteresis. A chief advantage of the present theory is that it is analytically tractable, in the sense that the complexity of the calculations may be reduced, with the aid of closed form analytical solutions, to the determination of the value of the phase field at point-obstacle sites. In particular, no numerical grid is required in calculations. The phase-field representation enables complex geometrical and topological transitions in the dislocation ensemble, including dislocation loop nucleation, bow-out, pinching, and the formation of Orowan loops. The theory also permits the consideration of obstacles of varying strengths and dislocation line-energy anisotropy. The theory predicts a range of behaviors which are in qualitative agreement with observation, including: hardening and dislocation multiplication in single slip under monotonic loading; the Bauschinger effect under reverse loading; the fading memory effect, whereby reverse yielding gradually eliminates the influence of previous loading; the evolution of the dislocation density under cycling loading, leading to characteristic `butterfly' curves; and others

The Muscular Dystrophy Association

Muscular dystrophy (MD) is a social problem because the people affected by it do not get to live a normal life.https://digitalscholarship.unlv.edu/educ_sys_202/1016/thumbnail.jp