Non-Abelian Chern-Simons-Higgs vortices with a quartic potential

We have constructed numerically non-Abelian vortices in an SU(2) Chern-Simons-Higgs theory with a quartic Higgs potential. We have analyzed these solutions in detail by means of improved numerical codes and found some unexpected features we did not find when a sixth-order Higgs potential was used. The generic non-Abelian solutions have been generated by using their corresponding Abelian counterparts as initial guess. Typically, the energy of the non-Abelian solutions is lower than that of the corresponding Abelian one (except in certain regions of the parameter space). Regarding the angular momentum, the Abelian solutions possess the maximal value, although there exist non-Abelian solutions which reach that maximal value too. In order to classify the solutions it is useful to consider the non-Abelian solutions with asymptotically vanishing $A_t$ component of the gauge potential, which may be labelled by an integer number $m$. For vortex number $n=3$ and above, we have found uniqueness violation: two different non-Abelian solutions with all the global charges equal. Finally, we have investigated the limit of infinity Higgs self-coupling parameter and found a piecewise Regge-like relation between the energy and the angular momentum.Comment: 9 pages, 13 figure

Voltage dip generator for testing wind turbines connected to electrical networks

This paper describes a new voltage dip generator that allows the shape of the time profile of the voltage generated to be configured. The use of this device as a tool to test the fault ride-through capability of wind turbines connected to the electricity grid can provide some remarkable benefits: First, this system offers the possibility of adapting the main features of the time–voltage profile generated (dip depth, dip duration, the ramp slope during the recovery process after clearing fault, etc.) to the specific requirements set forth by the grid operation codes, in accordance with different network electrical systems standards. Second, another remarkable ability of this system is to provide sinusoidal voltage and current wave forms during the overall testing process without the presence of harmonic components. This is made possible by the absence of electronic converters. Finally, the paper includes results and a discussion on the experimental data obtained with the use of a reduced size laboratory prototype that was constructed to validate the operating features of this new device

Estimulación vagal en el tratamiento de la epilepsia

The vagal nerve stimulation is a new technique for the treatment of drug resistant epilepsies. DEVELOPMENT: In 1997, it was approved in United States by the FDA to be used in adults with refractory focal epilepsies not candidates for epilepsy surgery. Its mechanism of action is unknown. The results in the controlled studies indicated a decrease of 30 50% in the seizure frequency in around 50% of the patients. Although more experience is needed to corroborate these results, it seems reasonable as a treatment for patients with difficult epilepsies, especially when the response to the antiepileptic drugs is poor or they are producing secondary effects, and the resection of the focus is not possible

Influencia de especies leñosas en el crecimiento aéreo de gramíneas perennes en pastizales semiáridos del centro de Argentina

The interaction between woody and grass species in semi-arid rangelands of central Argentina was assessed through the evaluation of the impact of woody species on grass growth over a 2-y period. The study comprised two morpho-physiologically different woody species and two cool-season perennial grass species highly preferred by domestic livestock. The study involved the assessment of total green length (TGL) and number of green leaves (NGL) per tiller in grasses growing beneath the canopy of woody species and in open rangeland areas. Soil temperature, pH and water, nitrogen, phosphorus and organic matter content were estimated at the same study sites. Precipitation during the study period was also recorded. Woody species induced higher TGL of grasses growing beneath their canopy when rainfall was near or above the long-term average for the study site and had no effect on NGL. Nitrogen and organic matter content of soils beneath the canopy of woody species were higher than values in open areas, while differences in the other soil parameters were scarce. Overall, the results of the present study suggest that woody species exert a facilitative effect on perennial grass species in semi-arid rangelands of central Argentina.La interacción entre especies leñosas y gramíneas en pastizales semiáridos del centro de Argentina fue evaluada a través del impacto de las especies leñosas sobre el crecimiento de las gramíneas durante un período de dos años. El estudio involucró a dos especies leñosas de diferentes características morfo-fisiológicas y a dos gramíneas perennes de ciclo otoño-inverno-primaveral altamente preferidas por el ganado doméstico. Se determinó la longitud total verde (LTV) y número de verdes hojas (NHV) por macolla en plantas de las gramíneas creciendo bajo la canopia de las especies leñosas y en sitios abiertos del pastizal; mientras que, la temperatura del suelo, pH y contenido de agua, nitrógeno, fósforo y materia orgánica se estimaron en los mismos sitios. También se registró la precipitación durante el período de estudio. Las gramíneas que crecieron bajo la canopia de las especies leñosas tuvieron mayor LTV cuando la precipitación fue similar o superior al promedio histórico del sitio de estudio; sin embargo, no se detectaron diferencias en el NHV. El contenido de nitrógeno y de materia orgánica en el suelo debajo de la canopia de las especies leñosas fue mayor que en los sitios abiertos; mientras que, las diferencias en los otros parámetros del suelo fueron escasas y las posibles causas de ello son discutidas. En general, los resultados del presente estudio sugieren que las especies leñosas ejercen un efecto facilitador sobre las gramíneas perennes en los pastizales semiáridos del centro de Argentina.Fil: Blazquez, Francisco Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Peláez, D. V.. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Andrioli, Romina Jessica. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Elia, Omar Raul. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentin

Quema controlada en una comunidad típica del Sudoeste Bonaerense

El fuego controlado reduce significativamente la cobertura de las especies leñosas y favorece el aumento de la cobertura de las gramíneas deseables e intermedias. Una sola quema controlada no afecta la densidad de las especies leñosas ni de las gramíneas forrajeras perennes.Fil: Pelaez, Daniel V.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Giorgetti, Hugo D.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Montenegro, Oscar A.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Elia, Omar Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Rodríguez, Gustavo D.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Andrioli, Romina Jessica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Blazquez, Francisco Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentin

Resolving galaxies in time and space: II: Uncertainties in the spectral synthesis of datacubes

In a companion paper we have presented many products derived from the application of the spectral synthesis code STARLIGHT to datacubes from the CALIFA survey, including 2D maps of stellar population properties and 1D averages in the temporal and spatial dimensions. Here we evaluate the uncertainties in these products. Uncertainties due to noise and spectral shape calibration errors and to the synthesis method are investigated by means of a suite of simulations based on 1638 CALIFA spectra for NGC 2916, with perturbations amplitudes gauged in terms of the expected errors. A separate study was conducted to assess uncertainties related to the choice of evolutionary synthesis models. We compare results obtained with the Bruzual & Charlot models, a preliminary update of them, and a combination of spectra derived from the Granada and MILES models. About 100k CALIFA spectra are used in this comparison. Noise and shape-related errors at the level expected for CALIFA propagate to 0.10-0.15 dex uncertainties in stellar masses, mean ages and metallicities. Uncertainties in A_V increase from 0.06 mag in the case of random noise to 0.16 mag for shape errors. Higher order products such as SFHs are more uncertain, but still relatively stable. Due to the large number statistics of datacubes, spatial averaging reduces uncertainties while preserving information on the history and structure of stellar populations. Radial profiles of global properties, as well as SFHs averaged over different regions are much more stable than for individual spaxels. Uncertainties related to the choice of base models are larger than those associated with data and method. Differences in mean age, mass and metallicity are ~ 0.15 to 0.25 dex, and 0.1 mag in A_V. Spectral residuals are ~ 1% on average, but with systematic features of up to 4%. The origin of these features is discussed. (Abridged)Comment: A&A, accepte

A numerical approach for liquefaction potential definition

Liquefaction phenomenon in saturated granular soil is not that frequent as amplification cases but can cause heavy damages on buildings and infrastructures whenever is occurs especially within superficial strata. In fact the lack of shear resistance of soil due to liquefaction affects mostly shallow foundations and road surfaces. Up now, several studies have been addressed to overpass the inadequacy of liquefaction safety factor by means of introducing the liquefaction potential. Nevertheless, the difficulty in (1) defining a scale of damage related to liquefaction potential values and (2) collecting field data from damages caused prevalently by liquefaction makes the punctual factor of safety still popular in engineering practice. In this paper a new approach to liquefaction potential estimation is proposed based on finite element dynamic analyses and on the concept of “significant volume” according to possible effects suffered by shallow foundations. One-dimensional simulation of liquefaction occurrence is performed by means of the Pastor-Zienkiewicz constitutive law. Hence the estimation of liquefaction potential is gained as well as the stress influence factor from Westergaard solution is calculated

Paresia poscrítica durante estudios de monitorización de vídeo-EEG

To know the frequency of Todd s paralysis during the video EEG monitoring studies, to investigate in its pathophysiology, and to confirm its value to localise the epileptic focus. PATIENTS AND METHODS: We reviewed 114 monitoring studies, in 102 patients. RESULTS: Sixty patients had epileptic seizures. An obvious paresis was noted in four seizures of two patients (3 and 1, respectively). Both patients had frontal epilepsy. During the paralysis, in the first patient the EEG showed ictal discharges on the contralateral centrotemporal area. In the second patient, the EEG demonstrated slow waves in the contralateral frontal region. The ictal onset was contralateral to the paresis in all cases. No patient with pseudoseizures had paralysis. CONCLUSIONS: Postconvulsive paralysis are not frequent in video EEG monitoring studies. However, if present it points out to a contralateral seizure onset. In our series it happened in patients with frontal seizures. The EEG may help to clarify if it correspond to a true postictal phenomenon or to a ictal paralysis