Hysteretic nonequilibrium Ising-Bloch transition

We show that a parametrically driven cubic-quintic complex Ginzburg-Landau equation exhibits a hysteretic nonequilibrium Ising-Bloch transition for large enough quintic nonlinearity. These results help to understand the recent experimental observation of this pheomenon [A. Esteban-Martin et al., Phys. Rev. Lett. 94, 223903 (2005)].Comment: 3 pages + six figure

Mass Transfer in Extractive Distillation when Using Ionic Liquids as Solvents

Mass transfer efficiency study in extractive distillation with ionic liquids for the mixtures water-ethanol and toluene-methylcyclohexane has been carried out in this work. Ionic liquids for the separation of these mixtures overcome the performance of the common volatile organic solvents. However, these also showed higher viscosities. A rated-based analysis was performed in order to quantify the effect of the solvent viscosity and relative volatility on mass transfer efficiency. In addition to this, an experimental analysis of the mass transfer efficiency was carried out experimentally in an extractive distillation pilot plant. The results indicated that, high liquid viscosities of ionic liquids should not affect the mass transfer efficiency negatively if the produced relative volatilities are sufficiently higher than those produced by organic solvents. However, when the ionic liquid showed very high viscosities or this solvent was present in large concentrations inside the column, the mass transfer efficiency decreases no matter how high the relative volatility is

Phase-locking of a Nonlinear Optical Cavity via Rocking: Transmuting Vortices into Phase Patterns

We report experimental observation of the conversion of a phase-invariant nonlinear system into a phase-locked one via the mechanism of rocking [G. J. de Valcarcel and K. Staliunas, Phys. Rev. E 67, 026604 (2003)]. This conversion results in that vortices of the phase-invariant system are being replaced by phase patterns such as domain walls. The experiment is carried out on a photorefractive oscillator in two-wave mixing configuration.A model for the experimental device is given that reproduces the observed behavior.Comment: 9 pages and 4 figure

Marikina flood hazard models using historical data of water level

In this paper, ten-year historical data of water levels recorded at Sto. Niño, Marikina station of MMDA-EFCOS were analysed and processed to determine the number of times per year (annual frequency) that critical levels of the Marikina River near the Sto. Niño station were reached and for how long (duration). Probability distributions for the annual frequency and duration were then fitted to the samples obtained. Monte Carlo simulation was applied in order to generate possible realizations of the random variables. Summary statistics were then obtained from the simulated values. Finally, backtesting using historical data of water levels after the period of model development was performed to check the validity of the models. The results showed that the models obtained were reliable. The results of this study may be used to guide the local government of Marikina in planning the needed resources in order to sufficiently respond in times of flooding incidents

Tetraspanin 6: A novel regulator of hippocampal synaptic transmission and long term plasticity

Tetraspanins (Tspan) are transmembrane proteins with important scaffold and signalling functions. Deletions of Tetraspanin 6 (Tspan6) gene, a member of the tetraspanin family, have been reported in patients with Epilepsy Female-restricted with Mental Retardation (EFMR). Interestingly, mutations in Tspan7, highly homologous to Tspan6, are associated with X-linked intellectual disability, suggesting that these two proteins are important for cognition. Considering recent evidences showing that Tspan7 plays a key role in synapse development and AMPAR trafficking, we initiated the study of Tspan6 in synaptic function using a Tspan6 knock out mouse model. Here we report that hippocampal field recordings from Tspan6 knock out mice show an enhanced basal synaptic transmission and impaired long term potentiation (LTP). A normal paired-pulse facilitation response suggests that Tspan6 affects the properties of the postsynaptic rather than the presynaptic terminal. However, no changes in spine morphology or postsynaptic markers could be detected in Tspan6 KO mice compared with wild types. In addition, Tspan6 KO mice show normal locomotor behaviour and no defects in hippocampus-dependent memory tests

Habitat-specific vegetation and seasonal drivers of bird community structure and function in southern Patagonian forests

Biodiversity conservation requires knowledge about the factors that influence the structure and function of biotic assemblages. In southern Patagonian Nothofagus forests, birds are the most abundant and diverse vertebrates and are known to have different requirements for nesting, breeding and feeding. Therefore, we chose this group to analyze key drivers of avian community dynamics; for conservation purposes, this information is requisite to manage Nothofagus forest landscapes and their associated biota. We first characterized forest structure and understory floristic composition in open and closed canopy broadleaved forests of mixed deciduous (MD) and mixed deciduous-evergreen (MDE) species on the southern coast of Tierra del Fuego National Park, Argentina. For each habitat, bird assemblages were assessed using point counts, checklists and mistnetting. We used ANOVAs and multivariate methods to analyze changes in bird species richness, density, and biomass as a function of habitat and seasonal characteristics. Forest structure and understory plant communities influenced avian assemblage and density; MDE forests had significantly greater species richness, but lower density than MD. Plus, particular species were associated with specific understory conditions, such as Anairetes parulus and Zonotrichia capensis whose presence was related to shrubs. Additionally, variations observed between seasons apparently were related to differential uses of each habitat type during certain times of year. Finally, it was not possible to define a single forest type with greater conservation value for birds; each had a specific bird species assemblage. Consequently, our results suggest the importance of a full representation of habitats to preserve the region’s bird diversity, which also has been described for forest invertebrates and understory plants

Comportamiento de Escherichia coli a bajas temperaturas en condiciones isotermales y no-isotermales

Comportamiento de Escherichia coli a bajas temperaturas en condiciones isotermales y no-isotermales. Se analizó el comportamiento de Escherichia coli a temperaturas subóptimas de crecimiento empleando cepas aisladas de queso de cabra tipo Crottin. Se realizaron tres grupos de experimentos en caldo de cultivo: A (5 ºC), B (7 ºC) y C (9 ºC). Para cada grupo se realizó un tratamiento de referencia en condiciones isotermales y cuatro tratamientos con diferentes períodos de abuso de temperatura a 25 ºC. El comportamiento se determinó por mediciones de DO. En condiciones isotermales se analizó con el modelo de Gompertz y dos modelos del programa DMfit. Se determinó la fase de latencia, la velocidad específica de crecimiento y la densidad máxima. No se observaron diferencias entre los tres modelos. En los tratamientos no-isotérmicos a 5 ºC y 7 ºC la población se incrementó en forma proporcional al tiempo de abuso a 25 ºC; a 9 ºC no hubo diferencias en el comportamiento para distintos períodos a temperatura elevada. Las diferencias podrían deberse al estado fisiológico de las células cuando se produce el incremento de la temperatura. Estos resultados enfatizan la necesidad de brindar mejor educación a la población sobre prácticas correctas de manipulación de los alimentos y evitar en consecuencia posibles riesgos para la salud.We analyzed the behavior of Escherichia coli at suboptimal growth temperature with strains isolated from Crottin goat¿s cheese. Three groups of experiments were carried out in broth culture at different incubation temperatures: A (5 º C), B (7 º C) and C (9 º C). A reference treatment in isothermal conditions was conducted for each group and four treatment with different periods at high temperature (25 ° C). The behavior was traced with OD measures. Isothermal treatments were analized by Gompertz model and two models of DMFit program. Lag time, specific growth rate and the maximum microbial density were determined. Parameters showed no clear overall preferences among the three models. At non-isothermal treatments the population increased proporcionally to period at 25 ºC for A and B groups. There was no difference among the different periods at high temperature for C group. The physiological cell state would be the cause of the differences in the number of generations observed among the groups. These findings underline the need for greater consumer education regarding safety food handling practices, in order to avoid potential health risks.Fil: Tamagnini, Lucia Maria. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Guzmán, María Carolina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Instituto de Investigación y Ciencia de Puerto del Rosario, Departamento de Biotecnología; EspañaFil: Rojo Lapalma, Felix Ramon. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomia y Física. Sección Física. Grupo de Teoria de la Materia Condensada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de Sousa, Gladys B.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Gonzalez, Ruben Dario. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Budde, Carlos Esteban. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin