Scalar field quasinormal modes on asymptotically locally flat rotating black holes in three dimensions

The pure quadratic term of New Massive Gravity in three dimensions admits asymptotically locally flat, rotating black holes. These black holes are characterized by their mass and angular momentum, as well as by a hair of gravitational origin. As in the Myers-Perry solution in dimensions greater than five, there is no upper bound on the angular momentum. We show that, remarkably, the equation for a massless scalar field on this background can be solved in an analytic manner and that the quasinormal frequencies can be found in a closed form. The spectrum is obtained requiring ingoing boundary conditions at the horizon and an asymptotic behavior at spatial infinity that provides a well-defined action principle for the scalar probe. As the angular momentum of the black hole approaches zero, the imaginary part of the quasinormal frequencies tends to minus infinity, migrating to the north pole of the Riemann Sphere and providing infinitely damped modes of high frequency. We show that this is consistent with the fact that the static black hole within this family does not admit quasinormal modes for a massless scalar probe.Comment: 17 pages, 5 figures. V2: improved figures. V3: typos corrected, references added and title slightly changed to match the version to appear in EPJ

Design of a fast computer-based partial discharge diagnostic system

Partial discharges cause progressive deterioration of insulating materials working in high voltage conditions and may lead ultimately to insulator failure. Experimental findings indicate that deterioration increases with the number of discharges and is consequently proportional to the magnitude and frequency of the applied voltage. In order to obtain a better understanding of the mechanisms of deterioration produced by partial discharges, instrumentation capable of individual pulse resolution is required. A new computer-based partial discharge detection system was designed and constructed to conduct long duration tests on sample capacitors. This system is capable of recording large number of pulses without dead time and producing valuable information related to amplitude, polarity, and charge content of the discharges. The operation of the system is automatic and no human supervision is required during the testing stage. Ceramic capacitors were tested at high voltage in long duration tests. The obtained results indicated that the charge content of partial discharges shift towards high levels of charge as the level of deterioration in the capacitor increases

Leadership best practices of Hispanic leaders in public organizations

The last five decades have seen the population of Hispanics in California rise from 16% to 39% (California State Data Center, 2013). As the number of Hispanics has grown, so has the number of Hispanics responsible for heading public organizations in the State. As more Hispanics obtain leadership positions, they face the same challenges that many other leaders’ face; to do more with less and to operate under the scrutiny of the citizens they represent (Kettle, 2009). The pressure to deliver effective and efficient services is further complicated by the hierarchical structure of public organizations; and the ideals of the old public administration, new public management, and new public service that shape how public administrations function today. The purpose of this study was to determine the best-practices that Hispanic leaders employ to make them successful in leading a public organization. This descriptive phenomenological study utilized a purposive sample of 10 participants who currently provide direct or indirect leadership to a public organization in their role as an elected official. Data was collected through semi-structured interviewed utilizing an eight-open ended question interview protocol. As a result, 6 key findings were identified. One notable finding was that Hispanic leaders of public organizations indicated that key components to their success included; (a) collaboration, (b) communication skills, and (c) continual engagement of internal and external stakeholders. As a result, this study identified current best-practices of Hispanic leaders in public organizations, which help inform current and future Hispanic leaders on what is required to lead a successful organization. It addition, it provides the components to develop a toolkit of diverse leadership skills and abilities that may assist Hispanic leaders navigating through the bureaucracy that engulfs public organizations

Responsabilidad social universitaria: un desafío de la universidad pública mexicana

El objetivo de este artículo es aportar elementos que permitan comprender cuál es la responsabilidad social de la universidad pública mexicana; para ello analizamos los modelos de universidades y algunos conceptos de responsabilidad social universitaria, con el fin de justificar el papel histórico de la universidad en el tiempo y en el espacio en que se ha desarrollado. Aquí se considera que imple- mentar una política de responsabilidad social universitaria implica un gradual y permanente proceso de transformación actitudinal, ya que la universidad, como ente creado por la sociedad, debe responder a las nuevas exigencias y reprogramar sustantivamente el crecimiento y difusión en el nuevo menester de gestión y vinculación universitaria.El objetivo de este artículo es aportar elementos que permitan comprender cuál es la responsabilidad social de la universidad pública mexicana; para ello analizamos los modelos de universidades y algunos conceptos de responsabilidad social universitaria, con el fin de justificar el papel histórico de la universidad en el tiempo y en el espacio en que se ha desarrollado. Aquí se considera que imple- mentar una política de responsabilidad social universitaria implica un gradual y permanente proceso de transformación actitudinal, ya que la universidad, como ente creado por la sociedad, debe responder a las nuevas exigencias y reprogramar sustantivamente el crecimiento y difusión en el nuevo menester de gestión y vinculación universitaria

Gastropod Larvae and Zooplankton in Reef-Related Areas of the Western Caribbean Sea

In order to estimate the composition, distribution and abundance of zooplankton in 3 areas off the western Caribbean, samples were collected in 15 stations at South Coast and Chinchorro Bank, Mexico, and Hol-Chan Belize, from April to December 1996. Duplicate samples (2.5 m3) were collected bimonthly using a submersible pump. The pumped water was filtered through a 202 μm mesh net yielding a total of 20 zooplankton groups. Chinchorro Bank had 19 groups, South Coast had 15 groups, and Hol-Chan had 14 groups. The most abundant groups were copepods (43.1%), fish eggs (29.0%), foraminifera (12.0%), decapod larvae (5.7%) and gastropod larvae (4.3%). Twenty-seven species of gastropod larvae were identified with Natica sp. 1, Rissoina sp. 1, Cerithiopsis hero, Cerithium atratum, and Epitonium sp.1 being dominant. Newly hatched veligers of Strombus gigas were collected only at Chinchorro Bank (5.7/10m-3). Zooplankton was diverse and showed marked changes during the sampling months. Chinchorro Bank had a higher number of marine zooplankters than South Coast and Hol-Chan, and this may be related to a greater oceanic influence. In spite of the environmental homogeneity, there were differences in the distribution and abundance of Strombus veligers, and this might be related to some water characteristics locally, affecting gastropod reproduction mainly in South Coast and Hol-Chan

Viverización y producción de plantones selectos de cinco ecotipos de rocoto (Capsicum pubescens) bajo condiciones agroclimáticas del Distrito de Molinopampa, Amazonas

El objetivo de la presente investigación fue evaluar la producción de plantones de cinco ecotipos de rocoto (Capsicum pubescens) mediante propagación botánica bajo las condiciones agroclimáticas del distrito de Molinopampa, Amazonas. Los ecotipos de rocoto utilizados fueron: campana, selva central, manzano, punta y gigante, los cuales se establecieron como tratamientos de estudio y evaluados bajo un diseño experimental completos al azar. El material vegetal (frutos frescos) se obtuvieron a partir de los productores de la provincia de Oxapampa, departamento de Pasco, se almacigaron las semillas y las actividades de manejo de plántulas se realizaron en el vivero. Los resultados de contenido de capsaicinoides en fruto y germinación de semillas favorecieron de manera significativa al ecotipo gigante, mientras que las variables referidas al nivel de sobrevivencia de plantones, altura de planta y número de hojas por planta mostraron efectos similares entre los cinco ecotipos de rocoto, sin mostrar diferencias estadísticas significativas.</p

Determinación de parámetros fisicoquímicos y productividad de cinco variedades de fresa (Fragaria spp.) cultivadas bajo sistema de acolchado en Molinopampa, Amazonas

El estudio tuvo como objetivo determinar los parámetros fisicoquímicos y productividad de frutos en cinco variedades de fresa, cultivadas en parcelas bajo sistema de acolchado en el distrito de Molinopampa,Amazonas. Las plantas fueron instaladas en parcelas experimentales bajo un diseño en bloques completos al azar, teniendo como factores de estudio a cinco variedaes de fresa y dos distanciamientos de siembra entre plantas, haciendo un total de diez tratamientos más un tratamiento testigo. Se aplicaron labores agronómicas a las plantas instaladas en parcelas durante la fase de desarrollo vegetativo. Para la medición de parámetros físicos de frutos se utlizaron equipos electrónicos (balanza y vernier de medida electrónica), mientras que para el análisis químico se recurrió a Calidad Total Laboratorios de la UNALM. Los mejores resultados sobre el análisis físico de frutos de fresa en términos de peso, diámetro axial y largo correspondieron a los tratamientos T5, T7, T8 y T6, cuyos tratamientos también resaltaron en la evaluación de productividad, los mismos que involucran a las variedades Albión y MMonterrey. Mientras que la evalución de contenido de sólidos solubles derterminó al tratamiento T7 (6,60 °Brix) como el de mejor respuesta. En tanto el análisis de acidez titulable favoreció al taratamiento T9 (0,53%).</p

Editorial: Sobre el difícil equilibrio de compaginar criterios de difusión y de transferencia en una revista sobre educación científica

Editoria

Editorial: Nuevos tiempos, nuevas formas

Editorial: New times, new format