Dynamics of the QCD String with Light and Heavy Quarks

The generalization of the effective action [1] of the quark--antiquark system in the confining vacuum is performed for the case of arbitrary quark masses. The interaction of quarks is described by the averaged Wilson loop for which we use the minimal area law asymptotics. The system is quantized by the path integral method and the quantum Hamiltonian is obtained. It contains not only quark degrees of freedom but also the string energy density. As well as in the equal masses case [1] two dynamical regimes are found [2]: for large orbital excitations ($l \gg 1$) the system is represented as rotating string, which leads to asymptotically linear Regge trajectories, while at small $l$ one obtains a potential-like relativistic or nonrelativistic regime. In the limiting cases of light-light and heavy-light mesons a unified description is developed [2]. For the Regge trajectories one obtains nearly straight-line patterns with the slope very close to $1/2 \pi \sigma$ and $1/ \pi\sigma$ correspondingly. The upper bound on the light quark(s) masses which doesn't change considerably this property of the trajectories is also found.Comment: 31 pages, preprint ITEP 62-9

Anatomically heterogeneous populations of CB cannabinoid receptor-expressing interneurons in the CA3 region of the hippocampus show homogeneous input-output characteristics

A subpopulation of GABAergic cells in cortical structures expresses CB1 cannabinoid receptors (CB1 ) on their axon terminals. To understand the function of these interneurons in information processing, it is necessary to uncover how they are embedded into neuronal circuits. Therefore, the proportion of GABAergic terminals expressing CB1 and the morphological and electrophysiological properties of CB1 -immunoreactive interneurons should be revealed. We investigated the ratio and the origin of CB1 -expressing inhibitory boutons in the CA3 region of the hippocampus. Using immunocytochemical techniques, we estimated that approximately 40% of GABAergic axon terminals in different layers of CA3 also expressed CB1 . To identify the inhibitory cell types expressing CB1 in this region, we recorded and intracellularly labeled interneurons in hippocampal slices. CB1 -expressing interneurons showed distinct axonal arborization, and were classified as basket cells, mossy-fiber-associated cells, dendritic-layer-innervating cells or perforant-path-associated cells. In each morphological category, a substantial variability in axonal projection was observed. In contrast to the diverse morphology, the active and passive membrane properties were found to be rather similar. Using paired recordings, we found that pyramidal cells displayed large and fast unitary postsynaptic currents in response to activating basket and mossy-fiber-associated cells, while they showed slower and smaller synaptic events in pairs originating from interneurons that innervate the dendritic layer, which may be due to dendritic filtering. In addition, CB1 activation significantly reduced the amplitude of the postsynaptic currents in each cell pair tested. Our data suggest that CB1 -expressing interneurons with different axonal projections have comparable physiological characteristics, contributing to a similar proportion of GABAergic inputs along the somato-dendritic axis of CA3 pyramidal cells. (c) 2014 Wiley Periodicals, Inc

Identification of glucose transporters in Aspergillus nidulans

o characterize the mechanisms involved in glucose transport, in the filamentous fungus Aspergillus nidulans, we have identified four glucose transporter encoding genes hxtB-E. We evaluated the ability of hxtB-E to functionally complement the Saccharomyces cerevisiae EBY.VW4000 strain that is unable to grow on glucose, fructose, mannose or galactose as single carbon source. In S. cerevisiae HxtB-E were targeted to the plasma membrane. The expression of HxtB, HxtC and HxtE was able to restore growth on glucose, fructose, mannose or galactose, indicating that these transporters accept multiple sugars as a substrate through an energy dependent process. A tenfold excess of unlabeled maltose, galactose, fructose, and mannose were able to inhibit glucose uptake to different levels (50 to 80 %) in these s. cerevisiae complemented strains. Moreover, experiments with cyanide-m-chlorophenylhydrazone (CCCP), strongly suggest that hxtB, -C, and –E mediate glucose transport via active proton symport. The A. nidulans ΔhxtB, ΔhxtC or ΔhxtE null mutants showed ~2.5-fold reduction in the affinity for glucose, while ΔhxtB and -C also showed a 2-fold reduction in the capacity for glucose uptake. The ΔhxtD mutant had a 7.8-fold reduction in affinity, but a 3-fold increase in the capacity for glucose uptake. However, only the ΔhxtB mutant strain showed a detectable decreased rate of glucose consumption at low concentrations and an increased resistance to 2-deoxyglucose.The authors would like to thank the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil for financial support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Oxidative stress-driven parvalbumin interneuron impairment as a common mechanism in models of schizophrenia.

Parvalbumin inhibitory interneurons (PVIs) are crucial for maintaining proper excitatory/inhibitory balance and high-frequency neuronal synchronization. Their activity supports critical developmental trajectories, sensory and cognitive processing, and social behavior. Despite heterogeneity in the etiology across schizophrenia and autism spectrum disorder, PVI circuits are altered in these psychiatric disorders. Identifying mechanism(s) underlying PVI deficits is essential to establish treatments targeting in particular cognition. On the basis of published and new data, we propose oxidative stress as a common pathological mechanism leading to PVI impairment in schizophrenia and some forms of autism. A series of animal models carrying genetic and/or environmental risks relevant to diverse etiological aspects of these disorders show PVI deficits to be all accompanied by oxidative stress in the anterior cingulate cortex. Specifically, oxidative stress is negatively correlated with the integrity of PVIs and the extracellular perineuronal net enwrapping these interneurons. Oxidative stress may result from dysregulation of systems typically affected in schizophrenia, including glutamatergic, dopaminergic, immune and antioxidant signaling. As convergent end point, redox dysregulation has successfully been targeted to protect PVIs with antioxidants/redox regulators across several animal models. This opens up new perspectives for the use of antioxidant treatments to be applied to at-risk individuals, in close temporal proximity to environmental impacts known to induce oxidative stress

Investigación del desarrollo prolongado de la escasez de agua para consumo humano y riego en la provincia de Petorca, región de Valparaíso

Tesis (Ingeniero Civil Industrial)En los capítulos de esta tesis, el lector encontrará una investigación acerca del desarrollo prolongado de la escasez de agua para consumo humano y riego en la Provincia de Petorca, Región de Valparaíso, cuyo objetivo principal es determinar los factores y/o variables que influyen en el desarrollo prolongado de la escasez de agua potable y riego en la Provincia de Petorca. Analizando los niveles hidrológicos, a través de una simulación en programa VENSIM. Durante la descripción de variables, se analizó cada una de estas y de qué manera influyen en el desarrollo de la sequía en la zona. Estas variables corresponden a: Precipitaciones, drenes, canales de regadío, población de la Provincia, hectáreas cultivadas, consumo de agua según el cultivo, acumuladores de agua, cobertura de agua potable, programa de Agua Potable Rural, pozos, camiones aljibes, agua para el riego, aporte de agua desde los deshielos, caudales del río Petorca y La Ligua y embalses. Posteriormente estas variables fueron incorporadas al programa VENSIM. Una vez incorporadas las variables al programa VENSIM a través de la formulación de ecuaciones de flujos con la asignación de valores adecuados a cada parámetro, se dio paso a una fase de análisis de resultados obtenidos y comparación de consistencia con la información real, a modo de comprobar el éxito de la utilización del simulador. La fase de simulación contempló tres análisis. El primero de ellos que refiere a la situación actual de la Provincia de Petorca. El segundo contempló un abastecimiento óptimo, es decir que es lo que se necesitaría en la zona afectada para dar cobertura total de agua a la población actual y a la cantidad de hectáreas cultivadas actuales. Y finalmente se realizó una proyección de la situación con base en una proyección de precipitaciones a diez años para la zona afectada. El resultado analítico y exhaustivo descrito en esta investigación demuestra que la situación de la Provincia de Petorca y específicamente en las tres comunas afectadas por la sequía, Cabildo, Petorca y La Ligua, deja de manifiesto que su situación es totalmente crítica y afecta grave y negativamente la calidad de vida de las personas y el desarrollo de la agricultura, que en años anteriores fue uno de los mejores a nivel país en la zona, ya que con los niveles de precipitaciones actuales, ni la población total rural ni las hectáreas cultivadas, pueden ser abastecidas con agua. Toma consistencia entonces, que la Provincia de Petorca se encuentre declarada como zona de escasez hídrica y los ríos Petorca y La Ligua están declaradas como fuentes hídricas agotadas. Esta investigación permitió constatar la situación actual y entregar análisis adicionales, brindando una herramienta que demostrado en esta investigación, permitirá mejorar la calidad de vida de las personas y la productividad de la Provincia de Petorca