Wide-field multi-color photometry of the Galactic globular cluster NGC 1261

(Abriged)This work studies in more detail the stellar population, including its photometric properties and characteristics, in the rarely studied southern Galactic globular cluster NGC 1261. We focus on the brighter sequences of the cluster's color-magnitude diagram (CMD). Like in our previous works, we rely upon photometry in several passbands to achieve more reliable results and conclusions. We carried out and analyzed new multi-color photometry of NGC 1261 in UBVI reaching below the turnoff point in all passbands in a fairly extended cluster field, about 14'x14'. We found several signs of the inhomogeneity ("multiplicity") in the stellar population. The most prominent of them are: (1) the dependence of the radial distribution of sub-giant branch (SGB) stars in the cluster on their U magnitude, with brighter stars less centrally concentrated at the 99.9 \% level than their fainter counterparts; (2) the dependence of the location of red giant branch (RGB) stars in the U-(U-B) CMD on their radial distance from the cluster center, with the portion of stars bluer in the (U-B) color increasing towards the cluster outskirts. Additionally, the radial variation of the RGB luminosity function in the bump region is suspected. We assume that both the SGB stars brighter in the U and the RGB stars bluer in the (U-B) color are probably associated with blue horizontal branch stars, because of a similarity in their radial distribution in the cluster. We estimated the metalicity of NGC 1261 from the slope of the RGB in U-based CMDs and the location of the RGB bump on the branch. These metallicity indicators give [Fe/H]zw = -1.34 +/- 0.16 dex and [Fe/H]zw = -1.41 +/- 0.10 dex, respectively. We isolated 18 probable blue straggler candidates. They are more centrally concentrated than the lower red giants of comparable brightness at the 97.9 \% level.Comment: 8 pages, 9 figures, accepted for publication in A&

Efecto de las cargas articulares en el flujo salival

69 p.OBJETIVO: Determinar el efecto de las cargas articulares en el flujo salival No Estimulado y Estimulado. MATERIALES Y MÉTODO: La muestra estuvo conformada por 30 sujetos, 15 hombres y 15 mujeres, entre 20 y 27 años de edad, alumnos de la carrera de Odontología de la Universidad de Talca, sin signos ni síntomas de TTM según la clasificación de Dworkin del año 1992. A estos se les midió el flujo salival No Estimulado y Estimulado antes de realizar cualquier intervención a modo de tener un parámetro de flujo. Posteriormente se confeccionó un dispositivo interoclusal con características de plano pivote a la altura de las piezas 1,5 y 2,5, para generar una carga articular cuando los sujetos ejerzan fuerza masticatoria. Los individuos usaron el plano pivote por 1 hora y luego se midió el flujo salival No Estimulado y Estimulado durante siete días consecutivos para observar las diferencias que pudiesen existir en el flujo salival luego de ejercer una carga articular. Para analizar la significancia estadística entre la diferencia de las medianas del flujo salival No Estimulado y Estimulado sin intervención con las medianas del flujo de los siete días de intervención, se utilizó la prueba No Paramétrica de Wilcoxon utilizando el software SPSS versión 15.0. RESULTADOS: El flujo salival No Estimulado, no presentó diferencia estadísticamente significativa (p>0.05) entre el flujo sin intervención y los siete días de prueba en ningún grupo del estudio. El flujo salival Estimulado presentó una disminución estadísticamente significativa (p<0.05), a partir del día tres de la prueba en relación al flujo sin intervención, en el total de la muestra, en el grupo de mujeres y en el grupo de hombres. CONCLUSIONES: Las cargas articulares no provocan alteraciones en el flujo salival No Estimulado. Las cargas articulares provocan disminución del flujo salival Estimulado

Cambios de presion y pulso, al aplicar un anestesico a diferente concentracion en su vasoconstrictor.

43 p.30 individuos sanos de 26 años de promedio, acudieron a las clínicas odontológicas de la Universidad de Talca a recibir un tratamiento de operatoria. Fueron citados para el estudio en 2 ocasiones con el fin de comparar los efectos sistémicos en presión sanguínea y pulso, provocados por una anestesia troncular mandibular con lidocaína 2% mas epinefrina al 1: 100.000 y al 1: 50.000. A cada individuo se le tomaron 3 registros por cada sesión. Uno antes de la inyección, el segundo inmediatamente después de la inyección, y el ultimo 3 minutos después de la inyección. No se observaron diferencias significativas al comparar los dos tipos de soluciones anestésicas. La presión sistólica no presento cambios después de la inyección, no se encontraron diferencias significativas entre los registros. La presión diastólica disminuyo, después de la inyección , y el pulso tuvo las mayores variaciones, aumentando significativamente después de la punción. La anestesia que contiene mayor cantidad de vasoconstrictor presento los valores mas altos. Las diferencias en la cantidad de vasoconstrictor de las soluciones que fueron estudiadas no es capas de producir variaciones significativas sobre la presión sanguínea y el pulso

Relacion entre recuerdo libre diferido y forma del discurso narrativo en adultos mayores

72 p.Los objetivos de esta investigación fueron: conocer y comparar el desempeño en tareas de recuerdo libre diferido y forma del discurso narrativo, en adultos mayores (AM) con envejecimiento normal y en adultos jóvenes (AJ). Además se realizó la correlación entre las variables mencionadas en el grupo de AM. Se evaluó ambos desempeños en 37 sujetos adultos mayores de 60 a 80 años de edad pertenecientes a Centros de Adulto Mayor; y 37 jóvenes entre 20 y 30 provenientes de Centros de Educación Integrada de Adultos; observando que no existe correlación significativa entre recuerdo libre diferido y forma del discurso narrativo en AM; tampoco hay diferencias en el recuerdo libre diferido entre AM y AJ, pero sí existen diferencias significativas en el total y en la forma de discurso narrativo entre AM y AJ. Finalmente se concluyó que el hecho que no existan diferencias significativas entre adultos mayores y jóvenes en cuanto al recuerdo libre, orienta a pensar en estrategias para revertir estas falencias en el grupo de menor edad y por otra parte, invita a prevenir, con el deterioro en aspectos cognitivos en los grupos de adulto mayor

The Infrared Ca II triplet as metallicity indicator

From observations of almost 500 RGB stars in 29 Galactic open and globular clusters, we have investigated the behaviour of the infrared Ca II triplet (8498, 8542 and 8662 \AA) in the age range 13$\leq$Age/Gyr$\leq$0.25 and the metallicity range $-2.2\leq$ [Fe/H] $\leq$+0.47. These are the widest ranges of ages and metallicities in which the behaviour of the Ca II triplet lines has been investigated in a homogeneous way. We report the first empirical study of the variation of the CaII triplet lines strength, for given metallicities, with respect to luminosity. We find that the sequence defined by each cluster in the Luminosity-$\Sigma$Ca plane is not exactly linear. However, when only stars in a small magnitude interval are observed, the sequences can be considered as linear. We have studied the the Ca II triplet lines on three metallicities scales. While a linear correlation between the reduced equivalent width ($W'_V$ or $W'_I$) versus metallicity is found in the \citet{cg97} and \citet{ki03} scales, a second order term needs to be added when the \citet{zw84} scale is adopted. We investigate the role of age from the wide range of ages covered by our sample. We find that age has a weak influence on the final relationship. Finally, the relationship derived here is used to estimate the metallicities of three poorly studied open clusters: Berkeley 39, Trumpler 5 and Collinder 110. For the latter, the metallicity derived here is the first spectroscopic estimate available.Comment: 52 pages, 16 figures, accepted for publication in Astronomical Journa

Kinematics of the Galactic Globular Cluster System: New Radial Velocities for Clusters in the Direction of the Inner Galaxy

HIRES on the Keck I telescope has been used to measure the first radial velocities for stars belonging to eleven, heavily-reddened globular clusters in the direction of the inner Galaxy. The question of kinematic substructuring among the Galactic globular cluster system is investigated using an updated catalog of globular cluster distances, metallicities and velocities. It is found that the population of metal-rich globular clusters shows significant rotation at all Galactocentric radii. For the metal-rich clusters within 4 kpc of the Galactic center, the measured rotation velocity and line-of-sight velocity dispersion are similar to those of bulge field stars. We investigate claims that the metal-rich clusters are associated with the central Galactic bar by comparing the kinematics of the innermost clusters to that of the atomic hydrogen in the inner Galaxy. The longitude-velocity diagram of both metal-rich and metal-poor clusters bears a remarkable similarity to that of the gas, including the same non-circular motions which have traditionally been interpreted as evidence for a Galactic bar, or, alternatively, a non-axisymmetric bulge. However, uncertainties in the existing three-dimensional Galactocentric positions for most of the clusters do not yet allow an unambiguous discrimination between the competing scenarios of membership in a rigidly rotating bar, or in a bulge which is an oblate isotropic rotator. We conclude that the majority of metal-rich clusters within the central 4 kpc of the Galaxy are probably associated with the bulge/bar, and not the thick disk. (ABRIDGED)Comment: 18 pages, including 7 of 13 postscript figures. Figures 1-6 available at http://astro.caltech.edu/~pc. Accepted for publication in the Astronomical Journa

A standard stellar library for evolutionary synthesis. III. Metallicity calibration

We extend the colour calibration of the widely used BaSeL standard stellar library (Lejeune, Cuisinier, & Buser 1997, 1998) to non-solar metallicities, down to [Fe/H] ~ -2.0 dex. Surprisingly, we find that at the present epoch it is virtually impossible to establish a unique calibration of UBVRIJHKL colours in terms of stellar metallicity [Fe/H] which is consistent simultaneously with both colour-temperature relations and colour-absolute magnitude diagrams (CMDs) based on observed globular cluster photometry data and on published, currently popular standard stellar evolutionary tracks and isochrones. The problem appears to be related to the long-standing incompleteness in our understanding of convection in late-type stellar evolution, but is also due to a serious lack of relevant observational calibration data that would help resolve, or at least further significant progress towards resolving this issue. In view of the most important applications of the BaSeL library, we here propose two different metallicity calibration versions: (1) the "WLBC 99" library, which consistently matches empirical colour-temperature relations and which, therefore, should make an ideal tool for the study of individual stars; and (2), the "PADOVA 2000" library, which provides isochrones from the Padova 2000 grid (Girardi et al., 2000) that successfully reproduce Galactic globular-cluster colour-absolute magnitude diagrams and which thus should prove particularly useful for studies of collective phenomena in stellar populations in clusters and galaxies.Comment: 15 pages, LaTeX, documentclass aa, accepted for A and

Construccion de un secador solar para madera aserrada

59 p.El presente estudio evalúa la eficiencia de un secador solar de fabricación nacional construido en la Universidad de Talca, Chile, basada en las condiciones climáticas y una inclinación relacionada a la radiación solar. Para esto se hizo un estudio de la intensidad de radiación solar y de la proyección de sombras que pudiesen existir en diferentes etapas del año, y en diferentes horarios. En la construcción del secador solar se utilizaron materiales que son accesibles fácilmente, además se utilizó como aislante térmico bolsas con aserrín. Se instaló un sistema de obtención de datos para controlar el funcionamiento del secado, el cual tuvo como función controlar la temperatura del secador, abriendo y cerrando las ventilas. El objetivo es encontrar un sistema de captura de energía solar eficiente, capturando la radiación solar para transformarla en temperatura dentro del secador. La energía capturada en 35º latitud sur con 71º latitud oeste para el mes de octubre se calculó con un gráfico de soleamiento. Además se calcularon las pérdidas de potencia del secador. Se puede concluir que el uso de un secador solar, es una buena alternativa, en la región, porque puede alcanzar un secado y un contenido de humedad similar al secado convencional a baja temperatura. SUMMARY This study evaluates the efficiency of a locally manufactured solar dryer built at the University of Talca, Chile, based on weather conditions and bias related to solar radiation. For this became a study of solar radiation and the projection of shadows that may exist in different stages of the year and at different times. In the construction of solar dryers used materials that are easily accessible, also used as thermal insulation bags with sawdust. It installed a data acquisition system for controlling the operation of drying, which had the function to control the temperature of the dryer vent opening and closing. The goal is to find a system of efficient solar energy capture, capturing sunlight and transforming it into temperature inside the dryer. The energy captured in latitude 35 degrees south latitude 71 ° west for the month of October was calculated with a graph of sunlight. In addition we calculated the power losses of the dryer. We conclude that using a solar dryer is a good alternative in the region because it can reach a drying and moisture content similar to conventional low temperature drying

CCD Photometry of Faint Variable Stars in the Globular Cluster NGC 6752

We present the results of a photometric survey for variable stars in the field of the nearby globular cluster NGC 6752. The cluster was monitored in 1996 and 1997 for a total of 54 hours with 3 different CCD cameras mounted on the 1.0-m Swope telescope. Eleven new variables were identified: 3 SX Phe stars, 7 contact binaries and 1 candidate detached eclipsing binary. All 3 SX Phe variables are likely members of the cluster while only 1 out of the 7 contact binaries is a potential cluster member. As a by-product of our survey we obtained UBV photometry for a large sample of stars in the cluster field. Two stars with U-B \approx -1.0 and V=19.3 and V=20.6 were identified. They lie along the extended horizontal branch of the cluster, and are likely to be faint sdB stars from NGC 6752.Comment: 18 pages, LaTex, 9 figures (Fig. 1 not available), accepted for publication in the Astronomical Journa