Global existence for two regularized MHD models in three space-dimension

The global existence of solutions for the 3D incompressible Euler equations is a major open problem. For the 3D inviscid MHD system, the global existence is an open problem as well. Our main concern in this paper is to understand which kind of regularization, of the form of alpha-regularization or partial viscous regularization, is capable to provide the global in time solvability for the 3D inviscid MHD system of equations. We consider two different regularized magnetohydrodynamic models for an incompressible fluid. In both cases, we provide a global existence result for the solution of the system

Ampelographic characteristics of the grape variety Malbec, cultivated in Mendoza (Argentina) : according to the O.I.V. method

De acuerdo con el programa Caracterización ampelográfica, fenológica y bioclimática de cepajes se ha actualizado la descripción de la variedad Malbec según normas homologadas internacionalmente. El método utilizado se ha basado en los Códigos de Caracteres Ampelográficos de la O.I.V., que abarcan: detallada observación de los órganos de la planta • sinónimos • origen, antecedentes y situación actual, • características ampelográficas y diferenciales • comportamiento agronómico y fenológico, • aptitud Los resultados conforman una ficha actualizada del cepaje, complementada con tomas fotográficas de brote, hoja, racimo, flor, baya y semilla.The grape variety Malbec description is part of the Ampelographic, phenologic and bioclimate characterization program. This work is an up-date of the descriptions existing actually according to present rules and internationally homologated standards. The description is based on methodology supply by O.I.V. on t detailed observation of the differents plant organs, synonymous, origin, antecedents, actual situation, ampelo-graphic and differential characteristics, agronomic and phenologic behavior, and aptitude. List of characters of grape varieties up to-date and completed with photograps of the shoot, leaf, bunch, flower, grain and seed.Fil: Rodríguez, José G. . Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Matus, Mirta Susana. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Catania, Carlos D.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Avagnina de Del Monte, Silvia . Universidad Nacional de Cuyo. Facultad de Ciencias Agraria

Genetically altered AMPA-type glutamate receptor kinetics in interneurons disrupt long-range synchrony of gamma oscillation

Gamma oscillations synchronized between distant neuronal populations may be critical for binding together brain regions devoted to common processing tasks. Network modeling predicts that such synchrony depends in part on the fast time course of excitatory postsynaptic potentials (EPSPs) in interneurons, and that even moderate slowing of this time course will disrupt synchrony. We generated mice with slowed interneuron EPSPs by gene targeting, in which the gene encoding the 67-kDa form of glutamic acid decarboxylase (GAD67) was altered to drive expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subunit GluR-B. GluR-B is a determinant of the relatively slow EPSPs in excitatory neurons and is normally expressed at low levels in γ-aminobutyric acid (GABA)ergic interneurons, but at high levels in the GAD-GluR-B mice. In both wild-type and GAD-GluR-B mice, tetanic stimuli evoked gamma oscillations that were indistinguishable in local field potential recordings. Remarkably, however, oscillation synchrony between spatially separated sites was severely disrupted in the mutant, in association with changes in interneuron firing patterns. The congruence between mouse and model suggests that the rapid time course of AMPA receptor-mediated EPSPs in interneurons might serve to allow gamma oscillations to synchronize over distance

A natural histone H2A variant lacking the Bub1 phosphorylation site and regulated depletion of centromeric histone CENP-A foster evolvability in Candida albicans.

Eukaryotes have evolved elaborate mechanisms to ensure that chromosomes segregate with high fidelity during mitosis and meiosis, and yet specific aneuploidies can be adaptive during environmental stress. Here, we identify a chromatin-based system required for inducible aneuploidy in a human pathogen. Candida albicans utilizes chromosome missegregation to acquire tolerance to antifungal drugs and for nonmeiotic ploidy reduction after mating. We discovered that the ancestor of C. albicans and 2 related pathogens evolved a variant of histone 2A (H2A) that lacks the conserved phosphorylation site for kinetochore-associated Bub1 kinase, a key regulator of chromosome segregation. Using engineered strains, we show that the relative gene dosage of this variant versus canonical H2A controls the fidelity of chromosome segregation and the rate of acquisition of tolerance to antifungal drugs via aneuploidy. Furthermore, whole-genome chromatin precipitation analysis reveals that Centromere Protein A/ Centromeric Histone H3-like Protein (CENP-A/Cse4), a centromeric histone H3 variant that forms the platform of the eukaryotic kinetochore, is depleted from tetraploid-mating products relative to diploid parents and is virtually eliminated from cells exposed to aneuploidy-promoting cues. We conclude that genetically programmed and environmentally induced changes in chromatin can confer the capacity for enhanced evolvability via chromosome missegregation