Central galaxies in different environments: Do they have similar properties?

We perform an exhaustive comparison among central galaxies from SDSS catalogs in different local environments at 0.01<=z<=0.08. The central galaxies are separated into two categories: group centrals (host halos containing satellites) and field centrals (host halos without satellites). From the latter, we select other two subsamples: isolated centrals and bright field centrals, both with the same magnitude limit. The stellar mass (Ms) distributions of the field and group central galaxies are different, which explains why in general the field central galaxies are mainly located in the blue cloud/star forming regions, whereas the group central galaxies are strongly biased to the red sequence/passive regions. The isolated centrals occupy the same regions as the bright field centrals since both populations have similar Ms distributions. At parity of Ms, the color and specific star formation rate (sSFR) distributions of the samples are similar, specially between field and group centrals. Furthermore, we find that the stellar-to-halo mass (Ms-Mh) relation of isolated galaxies does not depend on the color, sSFR and morphological type. For systems without satellites, the Ms-Mh relation steepens at high halo masses compared to group centrals, which is a consequence of assuming a one-to-one relation between group total stellar mass and halo mass. Under the same assumption, the scatter around the Ms-Mh relation of centrals with satellites increases with halo mass. Our results suggest that the mass growth of central galaxies is mostly driven by the halo mass, with environment and mergers playing a secondary role.Comment: 17 pages, 11 figures after last Referee's report. Accepted for publication in Ap

Flexibility at the margin and labor market volatility in OECD countries

We argue that segmented labor markets with flexibility at the margin (e.g., just affecting fixed-term employees) may achieve similar volatility than fully deregulated labor markets. Flexibility at the margin produces a gap in separation costs among matched workers that cause fixed-term employment to be the main workforce adjustment device. Moreover, in the presence of limitations in the duration and number of renewals of fixed-term contracts, firms respond by fostering labor turnover which further raises the volatility of the labor market. We present a matching model with temporary and permanent jobs where (i) the gap in firing costs and (ii) restrictions in the use of fixedterm contracts play the central role to explain the similar volatility observed in many regulated labor markets with flexibility at the margin vis-à-vis the fully deregulated ones.

Flexibility at the Margin and Labor Market Volatility in OECD Countries

We study whether segmented labor markets with flexibility at the margin (e.g., just affecting fixed-term employees) can achieve similar volatility than fully deregulated labor markets. Flexibility at the margin produces a gap in separation costs among matched workers that cause fixed-term employment to be the main workforce adjustment device, which in turn increases de labor market volatility. This increased volatility is partially reverted when limitations in the duration and number of renewals of fixed-term contracts are introduced. Under this scenario, firms respond by reducing the intensity of job destruction since it becomes more difficult to avoid firing costs in permanents contracts. We present a matching model with temporary and permanent jobs where (i) the gap in firing costs and (ii) restrictions in the use of fixed-term contracts helps explain the similar volatility observed in many regulated OECD labor markets with flexibility at the margin vis-à-vis the fully deregulated ones.separation costs, volatility, flexibility at the margin, matching model

Proposición de mejoras en el área de operaciones de una empresa vitivinícola

193 p.En Viña Los Vascos surge la necesidad de mejorar su área de operaciones debido al alto nivel de competitividad de las empresas del rubro. Así, en esta memoria se detectan los problemas y/o oportunidades de mejora y se plantean propuestas de solución. En primer lugar, se hace una descripción del área de operaciones de la empresa, donde se muestran sus objetivos, sus procesos y sus productos. Luego de tener clara la descripción y formalización se construyó y aplicó un cuestionario para hacer un diagnóstico del área, este sirvió como base para establecer los problemas y oportunidades de mejoras. Como resultado general se determinó analizar el sistema de planificación, la capacidad de los centros de trabajo y la gestión de materiales. En detalle, el diagnóstico entregó como resultado que no existe un plan de embotellado formal, no se posee un sistema que centralice la información, no se cuenta con datos históricos para analizar la efectividad del sistema productivo ni con información para el control de la producción, se observa un problema de humedad en las botellas en la línea de etiquetado, no hay un sistema MRP (Planificación de Requerimiento de Materiales) que entregue órdenes de trabajo ni planes de uso de materiales y, hay una baja rotación de inventario en algunos insumos importantes. Por otro lado, la eficiencia global de las líneas de producción es aceptable, con un 98,8% en embotellado y un 90,8% en etiquetado. Luego, los problemas determinados con el diagnóstico se priorizaron respecto a las necesidades y objetivos de la empresa, siendo los más relevantes: planificación de requerimientos de materiales (100% prioridad), gestión de inventarios (90%), control de inventarios (85%), control de la producción (85%) y planificación de la producción (80%). Hecha la selección por importancia e impacto, de los 7 problemas detectados quedaron sin abordar la capacidad de los centros de trabajo y el problema de humedad en las botellas. Con los problemas y/o oportunidades de mejoras seleccionadas se hace un primer análisis donde se define que los tres primeros temas se deben abordar en conjunto por su gran alcance y relación. Luego se hace un planteamiento de cada problema; se proponen cambios y nuevas formas de gestión para la planificación de materiales, donde se definen las funciones de lo

Neutral Hydrogen in the Ringed Barred Galaxies NGC 1433 and NGC 6300

We have made observations of the \ion{H}{1} in the southern ringed barred spiral galaxies NGC~1433 and NGC~6300 with the Australia Telescope Compact Array (ATCA), the main goal being to test the resonance theory for the origin of these rings. NGC~1433 is the prototypical ringed barred spiral, and displays distinct \ion{H}{1}~counterparts to its nuclear ring, inner ring, outer pseudoring, and plume-like features. The $L_{4}$ and $L_{5}$ regions at corotation, as well as the bar itself, are relatively devoid of neutral atomic hydrogen. By associating the inner ring of NGC~1433 with the inner second harmonic resonance, and its outer pseudoring with the outer Lindblad resonance, we are able to infer a bar pattern speed for NGC~1433 of $26\pm5$~km~s$^{-1}$~kpc$^{-1}$. By way of contrast, NGC~6300 possesses a much more extended \ion{H}{1}~disk than NGC~1433. There is a gas ring underlying the inner pseudoring, but it is both broader and slightly larger in diameter than the optical feature. By again linking this inner ring feature to the inner second harmonic resonance, we derive a bar pattern speed for NGC~6300 of $27\pm8$~km~s$^{-1}$~kpc$^{-1}$, but in this case, neither the outer pseudoring nor the nuclear ring predicted by the resonance-ring theory can be identified in NGC~6300. Although it may be the case that the ring in NGC~6300 is not related to a resonance with the bar at all, we postulate instead that NGC~6300 is merely a less well-developed example of a resonance-ring galaxy than is NGC~1433.Comment: 21 pages, aas2pp4 LaTeX, no figures included. Accepted for April 1 1996 ApJ. Full paper (with figures) available from http://www.phys.unsw.edu.au/~sdr/prep.htm

Auditoria a las cuentas corrientes bancarias en un sistema computarizado

220 p.El presente trabajo contempla el Estudio del Movimiento Generalizado de las Cuentas Corrientes en los bancos comerciales de nuestro país con el objeto de tomar conocimiento respecto al funcionamiento de 1a Cuenta Corriente Bancaria en Chile, ello ha permitido desarrollar una secuencia metodologica para la realización de una Auditoria a las Cuentas Corrientes Bancarias, sea que el procesamiento de la información se realice en forma manual o computarizada. La realización de esta investigación, fue posible gracias a la inquietud de un grupo do alumnos, quienes conscientes de la importancia que reviste la Cuenta Corriente bancaria en la economía actual Como fuente de financiamiento bancario y su relación con el Procesamiento Electrónico de datos, vieron la necesidad de contar con una herramienta metodologica que permite evaluar la razonabilidad del saldo de las cuentas corrientes presentado en los Estados Financieros Bancarios. Este seminario fue confeccionado durante el segundo semestre del año 1982 y primer semestre de 1983, por un grupo de alumnos de la Escuela de Ciencias Económicas y Administrativas de la universidad de Talca, como requisito para completar el Plan de Estudios de la carrera de Contador Público y Contador Auditor

Linear Matrix Inequality Design of Exponentially Stabilizing Observer-Based State Feedback Port-Hamiltonian Controllers

The design of an observer-based state feedback (OBSF) controller with guaranteed passivity properties for port-Hamiltonian systems (PHS) is addressed using linear matrix inequalities (LMIs). The observer gain is freely chosen and the LMIs conditions such that the state feedback is equivalent to control by interconnection with an input strictly passive (ISP) and/or an output strictly passive (OSP) and zero state detectable (ZSD) port-Hamiltonian controller are established. It is shown that the proposed controller exponentially stabilizes a class of infinite-dimensional PHS and asymptotically stabilizes a class of finite-dimensional non-linear PHS. A Timoshenko beam model and a microelectromechanical system are used to illustrate the proposed approach