2GHz MIMO channel model from experimental outdoor data analysis in UMTS

The key objective of this work was to obtain a MIMO model for a line of sight (LOS) channel component as well as the covariance matrix for a non-LOS deployment. A maximum likelihood criteria is applied to obtain a LOS spatial signature vector and a NLOS covariance matrix derived from channel measurements taken in the 2 GHz UMTS spectrum for an urban deployment in Bristol (UK). Different user equipment deployments were considered to represent both LOS and NLOS, as well as static and dynamic (motion) situations. The parameters of interest were estimated from these data and the fitness model was satisfactorily evaluated in all cases. Further, the Kronecker product between transmitter and receiver matrices was evaluated in order to simplify the model, for both, LOS and NLOS cases, including polarization diversity cases.The key objective of this work was to obtain a MIMO model for a line of sight (LOS) channel component as well as the covariance matrix for a non-LOS deployment. A maximum likelihood criteria is applied to obtain a LOS spatial signature vector and a NLOS covariance matrix derived from channel measurements taken in the 2 GHz UMTS spectrum for an urban deployment in Bristol (UK). Different user equipment deployments were considered to represent both LOS and NLOS, as well as static and dynamic (motion) situations. The parameters of interest were estimated from these data and the fitness model was satisfactorily evaluated in all cases. Further, the Kronecker product between transmitter and receiver matrices was evaluated in order to simplify the model, for both, LOS and NLOS cases, including polarization diversity cases

The VirS/VirR two-component system regulates the anaerobic cytotoxicity, intestinal pathogenicity, and enterotoxemic lethality of Clostridium perfringens type C isolate CN3685.

Clostridium perfringens vegetative cells cause both histotoxic infections (e.g., gas gangrene) and diseases originating in the intestines (e.g., hemorrhagic necrotizing enteritis or lethal enterotoxemia). Despite their medical and veterinary importance, the molecular pathogenicity of C. perfringens vegetative cells causing diseases of intestinal origin remains poorly understood. However, C. perfringens beta toxin (CPB) was recently shown to be important when vegetative cells of C. perfringens type C strain CN3685 induce hemorrhagic necrotizing enteritis and lethal enterotoxemia. Additionally, the VirS/VirR two-component regulatory system was found to control CPB production by CN3685 vegetative cells during aerobic infection of cultured enterocyte-like Caco-2 cells. Using an isogenic virR null mutant, the current study now reports that the VirS/VirR system also regulates CN3685 cytotoxicity during infection of Caco-2 cells under anaerobic conditions, as found in the intestines. More importantly, the virR mutant lost the ability to cause hemorrhagic necrotic enteritis in rabbit small intestinal loops. Western blot analyses demonstrated that the VirS/VirR system mediates necrotizing enteritis, at least in part, by controlling in vivo CPB production. In addition, vegetative cells of the isogenic virR null mutant were, relative to wild-type vegetative cells, strongly attenuated in their lethality in a mouse enterotoxemia model. Collectively, these results identify the first regulator of in vivo pathogenicity for C. perfringens vegetative cells causing disease originating in the complex intestinal environment. Since VirS/VirR also mediates histotoxic infections, this two-component regulatory system now assumes a global role in regulating a spectrum of infections caused by C. perfringens vegetative cells

Citología exfoliativa oral como medio de orientación diagnóstico

El estudio de los elementos celulares que se descaman de las su­perficies epiteliales de la mucosa de la cavidad oral debido al proceso de renovación constante de estos elementos, a expensas de las células de la capa basal, constituye un método relativamente nuevo en el campo del diagnóstico citológico. El interés de la citología exfoliativa aplicada al ámbito de la estomatología, no empezó a adquirir importancia hasta principios del año 1950, con los trabajos de MONTGOMERY, WAKI, ScHREU, DORNER y SANDLER..

Un modelo conceptual sobre el funcionamiento de los ríos mediterráneos sometidos a perturbaciones naturales (riadas y sequías)

The Mediterranean regions are prone to suffer extraordinary flash-floods and prolonged droughts. Between these extreme events, there are small floods and droughts that are more common and more predictable. These smaller floods and droughts, along with the others mentioned before generate an extraordinarily complex temporal hydrological picture whose affects have been partly described by different authors, including those affecting the human population. The information compiled during nearly two decades by the group of Ecology of Continental Waters of the University of Murcia, about the effects of these events on rivers of the Segura River Basin, allows for elaborating a conceptual model about the function of several physical, physico-chemical, and biological parameters in rivers in the southwest, in particular and Mediterranean rivers in general.Las regiones mediterráneas son proclives a sufrir avenidas extraordinarias y sequías prolongadas. Entre estos eventos extremos, se sitúan las crecidas y estiajes más habituales y predecibles que, junto a los anteriores configuran un cuadro hidrológico temporal extraordinariamente complejo cuyos efectos han sido descritos parcialmente por diferentes autores, incluidos aquellos que afectan a la población humana. La información recogida durante casi dos décadas por el Grupo de Ecología de Aguas Continentales de la Universidad de Murcia, sobre los efectos de estos eventos en ríos de la Cuenca del Segura, permite elaborar un modelo conceptual sobre el funcionamiento de distintos parámetros físicos, físico-químicos y biológicos en ríos del sureste, en particular y mediterráneos, en general

Componentes de la producción en un cultivo de Vicia Faba sometido a fertilización nitrogenada

Peer Reviewe

Correlation function and mutual information

Correlation function and mutual information are two powerful tools to characterize the correlations in a quantum state of a composite system, widely used in many-body physics and in quantum information science, respectively. We find that these two tools may give different conclusions about the order of the degrees of correlation in two specific two-qubit states. This result implies that the orderings of bipartite quantum states according to the degrees of correlation depend on which correlation measure we adopt.Comment: 4.2 pages, 4 figure

Radio astrometry with chromatic AGN core positions

Aims: The effect of frequency-dependent AGN core positions (``core-shifts'') on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods: The basic equations relating to VLBI astrometry are reviewed, including the effects of source structure. A power-law representation of core-shifts, based on both observations and theoretical considerations of jet conditions, is incorporated. Results: It is shown that, in the presence of core-shifts, phase and group-delay astrometry measurements yield different positions. For a core displacement from the jet base parametrized by Delta x (lambda) = k lambda^beta group delays measure a ``reduced'' core-shift of (1-beta) Delta x (lambda). For the astrophysically-significant case of beta = 1, group delays measure no shift at all, giving the position of the jet base. At 8.4 GHz an estimated typical offset between phase and group-delay positions of ~170 uas is smaller than the current ~250 uas precision of group-delay positions of the sources used to define the ICRF; however, this effect must be taken into account for future measurements planned with improved accuracy when comparing with optical positions of AGN to be obtained with the GAIA mission.Comment: Accepted for publication in Astronomy & Astrophysics, 4 page

Caracterización hidroquímica del complejo de humedales El Yali, Chile Central

Within the wetlands of the semiarid region of Central Chile, The Yali wetlands complex is the most important because it is protected as a RAMSAR's wetland. However, information about their hydro-geomorphological characteristics is almost non existent. In this study, the hydrochemical characteristics of 20 sampling sites, surveyed in July 2008 and which include coastal lagoons, estuaries, streams, saltmarshes, and reservoirs, were analyzed. The hydrochemical complexity stands out in relation to the water salinity (range = 320 − 58 800 μS/cm) and ionic composition of the studied wetlands in relation to the relative importance of the dominant water flow that sustains these wetlands. In relation to trophic state, most of the studied wetland systems are eutrophic or hypertrophic (medium values for total nitrogen = 4.7 mg/l; and soluble reactive phosphorus = 0.4 mg/l) due to the existing use of land (eucalyptus forests, cattle farms and wastewater inputs).Dentro de los humedales de la región semiárida Central de Chile, destaca el complejo denominado El Yali, por su condición de protección como Humedal RAMSAR, del que apenas existe información sobre sus características hidrogeomorfológicas. En este estudio se analiza la hidroquímica de 20 puntos de muestreo, realizados en julio de 2008, incluyendo lagunas, estuarios, esteros, salinas y embalses. Destaca su complejidad hidroquímica en relación con la salinidad (rango = 320 − 58 800 μS/cm) y el contenido iónico de los humedales estudiados en función de la importancia relativa del flujo de agua dominante. En cuanto al estado trófico, la mayoría de los sistemas estudiados son eutróficos o hipertróficos (valores medios de nitrógeno total =4.7 mg/l; y SRP (fósforo reactivo soluble) = 0.4 mg/l), como consecuencia del uso del territorio (plantaciones de eucaliptos, explotaciones ganaderas y vertidos orgánicos)

Ribosomal S6K1 in POMC and AgRP Neurons Regulates Glucose Homeostasis but Not Feeding Behavior in Mice.

SummaryHypothalamic ribosomal S6K1 has been suggested as a point of convergence for hormonal and nutrient signals in the regulation of feeding behavior, bodyweight, and glucose metabolism. However, the long-term effects of manipulating hypothalamic S6K1 signaling on energy homeostasis and the cellular mechanisms underlying these roles are unclear. We therefore inactivated S6K1 in pro-opiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, key regulators of energy homeostasis, but in contrast to the current view, we found no evidence that S6K1 regulates food intake and bodyweight. In contrast, S6K1 signaling in POMC neurons regulated hepatic glucose production and peripheral lipid metabolism and modulated neuronal excitability. S6K1 signaling in AgRP neurons regulated skeletal muscle insulin sensitivity and was required for glucose sensing by these neurons. Our findings suggest that S6K1 signaling is not a general integrator of energy homeostasis in the mediobasal hypothalamus but has distinct roles in the regulation of glucose homeostasis by POMC and AgRP neurons