On the Superradiance of Spin-1 Waves in an Equatorial Wedge around a Kerr Hole

Recently Van Putten has suggested that superradiance of magnetosonic waves in a toroidal magnetosphere around a Kerr black hole may play a role in the central engine of gamma-ray bursts. In this context, he computed (in the WKB approximation) the superradiant amplification of scalar waves confined to a thin equatorial wedge around a Kerr hole and found that the superradiance is higher than for radiation incident over all angles. This paper presents calculations of both spin-0 (scalar) superradiance (integrating the radial equation rather than using the WKB method) and and spin-1 (electromagnetic/magnetosonic) superradiance, in Van Putten's wedge geometry. In contrast to the scalar case, spin-1 superradiance decreases in the wedge geometry, decreasing the likelihood of its astrophysical importance.Comment: Submitted to The Astrophysical Journal Letter

Regulating Eternal Inflation II: The Great Divide

In a previous paper, two of the authors presented a "regulated" picture of eternal inflation. This picture both suggested and drew support from a conjectured discontinuity in the amplitude for tunneling from positive to negative vacuum energy, as the positive vacuum energy was sent to zero; analytic and numerical arguments supporting this conjecture were given. Here we show that this conjecture is false, but in an interesting way. There are no cases where tunneling amplitudes are discontinuous at vanishing cosmological constant; rather, the space of potentials separates into two regions. In one region decay is strongly suppressed, and the proposed picture of eternal inflation remains viable; sending the (false) vacuum energy to zero in this region results in an absolutely stable asymptotically flat space. In the other region, we argue that the space-time at vanishing cosmological constant is unstable, but not asymptotically Minkowski. The consequences of our results for theories of supersymmetry breaking are unchanged.Comment: JHEP3, 19 Pages, 7 Figure

Suicide Within United States Jails: A Qualitative Interpretive Meta-synthesis

Suicide was the leading cause of unnatural deaths in local jails, accounting for 29% of all jail deaths between 2000 and 2007. Though much literature exists on suicide in jails, very little is qualitative. Additionally, little attention has been focused on how the Interpersonal Theory of Suicide applies to the jail environment. To gain a better understanding of suicide in jails, an interpretive meta-synthesis of three qualitative articles was conducted. The combined sample included thirty-four individuals from three jails. These three articles were analyzed to identify common themes that led inmates to suicide. Three broad categories were identified through constant comparison of the data. These categories are: mental health factors, environmental conditions, and relationship issues. These three broad categories are discussed in relation to the Interpersonal Theory of Suicide, demonstrating its application in the jail setting. This information is essential for correctional facilities and staff for use in their day-to-day interactions with inmates. Future research is needed to identify and examine current suicide prevention programs in the United States penal system

La narrativa indigenista a la luz del modelo estructural.

Sin resume

Measuring the extent of convective cores in low-mass stars using Kepler data: towards a calibration of core overshooting

Our poor understanding of the boundaries of convective cores generates large uncertainties on the extent of these cores and thus on stellar ages. Our aim is to use asteroseismology to consistently measure the extent of convective cores in a sample of main-sequence stars whose masses lie around the mass-limit for having a convective core. We first test and validate a seismic diagnostic that was proposed to probe in a model-dependent way the extent of convective cores using the so-called $r_{010}$ ratios, which are built with $l=0$ and $l=1$ modes. We apply this procedure to 24 low-mass stars chosen among Kepler targets to optimize the efficiency of this diagnostic. For this purpose, we compute grids of stellar models with both the CESAM2k and MESA evolution codes, where the extensions of convective cores are modeled either by an instantaneous mixing or as a diffusion process. Among the selected targets, we are able to unambiguously detect convective cores in eight stars and we obtain seismic measurements of the extent of the mixed core in these targets with a good agreement between the CESAM2k and MESA codes. By performing optimizations using the Levenberg-Marquardt algorithm, we then obtain estimates of the amount of extra-mixing beyond the core that is required in CESAM2k to reproduce seismic observations for these eight stars and we show that this can be used to propose a calibration of this quantity. This calibration depends on the prescription chosen for the extra-mixing, but we find that it should be valid also for the code MESA, provided the same prescription is used. This study constitutes a first step towards the calibration of the extension of convective cores in low-mass stars, which will help reduce the uncertainties on the ages of these stars.Comment: 27 pages, 15 figures, accepted in A&

Embedding the Pentagon

The Pentagon Model is an explicit supersymmetric extension of the Standard Model, which involves a new strongly-interacting SU(5) gauge theory at TeV-scale energies. We show that the Pentagon can be embedded into an SU(5) x SU(5) x SU(5) gauge group at the GUT scale. The doublet-triplet splitting problem, and proton decay compatible with experimental bounds, can be successfully addressed in this context. The simplest approach fails to provide masses for the lighter two generations of quarks and leptons; however, this problem can be solved by the addition of a pair of antisymmetric tensor fields and an axion.Comment: 39 page

Violencia de género en el ámbito familiar : Dispositivo enfocado al tratamiento de hombres que presentan conductas violentas en las relaciones de pareja

Al abordar la temática de la violencia de género, particularmente la ejercida por hombres en el ámbito familiar, desde una perspectiva de poder sobre la mujer que comparte con él una relación patológica o enfermiza, planteamos los siguientes interrogantes: ¿Es posible desactivar situaciones de violencia familiar enfocando nuestra energía solamente al trabajo con las victimas? ¿Qué estamos haciendo hoy para evitar la reincidencia de hechos de violencia? ¿Un hombre agresor, deja de serlo simplemente cuando una pareja se disuelve y se establecen nuevos vínculos? ¿Podemos intervenir de alguna manera para evitar la repetición generacional de modelos violentos? ¿Por qué trabajar con agresores? ¿Es posible y necesario? Creemos firmemente que un abordaje integral en torno a la violencia familiar, impone la necesidad de respuestas alternativas. La conducta ejercida a través de la violencia, automáticamente produce rechazo. Tendemos casi instintivamente a tomar distancia y a reprobar todo acto que exceda los límites permitidos o aceptados social y legalmente. (Párrafo extraído del texto a modo de resumen)Eje 12: Mujeres y acceso a la justiciaFacultad de Humanidades y Ciencias de la Educació

Spatial Structure of Ion Beams in an Expanding Plasma

We report spatially resolved perpendicular and parallel, to the magnetic field, ion velocity distribution function (IVDF) measurements in an expanding argon helicon plasma. The parallel IVDFs, obtained through laser induced fluorescence (LIF), show an ion beam with v ≈ 8000 m/s flowing downstream and confined to the center of the discharge. The ion beam is measurable for tens of centimeters along the expansion axis before the LIF signal fades, likely a result of metastable quenching of the beam ions. The parallel ion beam velocity slows in agreement with expectations for the measured parallel electric field. The perpendicular IVDFs show an ion population with a radially outward flow that increases with distance from the plasma axis. Structures aligned to the expanding magnetic field appear in the DC electric field, the electron temperature, and the plasma density in the plasma plume. These measurements demonstrate that at least two-dimensional and perhaps fully three-dimensional models are needed to accurately describe the spontaneous acceleration of ion beams in expanding plasmas

Impact of Level of Use on Plant Vigor and Weight of \u3cem\u3eFestuca humilior\u3c/em\u3e and \u3cem\u3eCalamagrostis vicunarum\u3c/em\u3e

Tussock grasslands of Festuca humilior and Calamagrostis vicunarum cover a significant extension of the central Andes of Peru, constituting a plant association highly appreciated by cattle ranchers. The objective of this research was to estimate the cumulative impact of the level of use of the key grasses Festuca humilior and Calamagrostis vicunarum on plant height, vigor, and weight. This study was conducted in a humid grassland of regular condition located at 4186 masl in the Puna ecoregion. The variables evaluated were: plant height, basal and canopy diameter and plant weight. The experiment lasted two years in which individual plants from both species were cut every four months. The vigor resulted from the regression of the weight (g) and the volume (cm3) of the plant. Height (cm) was the length from the soil surface to the flag leaf. The experimental design was a randomized block design with a 2x3 factorial arrangement, two species and three height removal levels: zero, 40 and 80%. The height, vigor and weight of Festuca humilior and Calamagrostis vicunarum decreased in response to increasing use levels, but the changes were more evident in Festuca than in Calamagrostis. While the decrease in the evaluated variables was constant for Festuca humilior as the level of use increased, Calamagrostis also decreased, but to a lesser extent, remaining almost unchanged when biomass removal levels changed from moderate to heavy, suggesting that this species was more tolerant to grazing. The results helped explaining why in fields dominated by Festuca humilior and sub-dominated by Calamagrostis vicunarum subjected to intense grazing, dominance relationships change in favor of Calamagrostis, a species of lower forage value than Festuca humilior. It is recommended to manage the grazing system under a low-intensity and low frequency regime

Long distance synchronization of mobile robots

This paper considers the long distance master-slave and mutual synchronization of unicycle-type mobile robots. The issues that arise when the elements of a robotic network are placed in different locations are addressed, specifically the time-delay induced by the communication channel linking the robots. Experiments between wirelessly controlled mobile robots located in Eindhoven, The Netherlands and Tokyo, Japan demonstrate the applicability of the proposed approach