2,516 research outputs found

    The solar siblings in the Gaia era

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    We perform realistic simulations of the Sun's birth cluster in order to predict the current distribution of solar siblings in the Galaxy. We study the possibility of finding the solar siblings in the Gaia catalogue by using only positional and kinematic information. We find that the number of solar siblings predicted to be observed by Gaia will be around 100 in the most optimistic case, and that a phase space only search in the Gaia catalogue will be extremely difficult. It is therefore mandatory to combine the chemical tagging technique with phase space selection criteria in order to have any hope of finding the solar siblings.Comment: To be published in the proceedings of the GREAT-ITN conference "The Milky Way Unravelled by Gaia: GREAT Science from the Gaia Data Releases", 1-5 December 2014, University of Barcelona, Spain, EAS Publications Series, eds Nicholas Walton, Francesca Figueras, and Caroline Soubira

    The evolution of the Sun's birth cluster and the search for the solar siblings with Gaia

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    We use self-consistent numerical simulations of the evolution and disruption of the Sun's birth cluster in the Milky Way potential to investigate the present-day phase space distribution of the Sun's siblings. The simulations include the gravitational N-body forces within the cluster and the effects of stellar evolution on the cluster population. In addition the gravitational forces due to the Milky Way potential are accounted for in a self-consistent manner. Our aim is to understand how the astrometric and radial velocity data from the Gaia mission can be used to pre-select solar sibling candidates. We vary the initial conditions of the Sun's birth cluster, as well as the parameters of the Galactic potential. We show that the disruption time-scales of the cluster are insensitive to the details of the non-axisymmetric components of the Milky Way model and we make predictions, averaged over the different simulated possibilities, about the number of solar siblings that should appear in surveys such as Gaia or GALAH. We find a large variety of present-day phase space distributions of solar siblings, which depend on the cluster initial conditions and the Milky Way model parameters. We show that nevertheless robust predictions can be made about the location of the solar siblings in the space of parallaxes (ϖ\varpi), proper motions (μ\mu) and radial velocities (VrV_\mathrm{r}). By calculating the ratio of the number of simulated solar siblings to that of the number of stars in a model Galactic disk, we find that this ratio is above 0.5 in the region given by: ϖ≥5\varpi \geq 5mas, 4≤μ≤64 \leq \mu \leq 6masyr−1^{-1}, and −2≤Vr≤0-2\leq V_\mathrm{r} \leq 0kms−1^{-1}. Selecting stars from this region should increase the probability of success in identifying solar siblings through follow up observations [Abridged].Comment: 13 pages, 7 figures. Accepted for publication in MNRA

    Successes and challenges in public transport policies : comparative analysis of the innovations in the provision of the public passenger transport service in the cities of Curitiba, Brazil; Santiago de Chile, Chile; and Rosario, Argentina

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    En esta artículo realizamos un análisis comparativo de los sistemas de servicio de transporte público de pasajeros en las ciudades de Curitiba, Brasil; Santiago de Chile, Chile y Rosario, Argentina para poder comparar las similitudes, diferencias y dificultades que presentan estos sistemas en la etapa de implementación de las políticas públicas; como así también presentar una sistematización de las políticas, instrumentos y acciones que permitieron gestionar con éxito las reestructuraciones de los sistemas de transporte y sus aportes para el desarrollo de una Política pública de transporte en el Gran Mendoza.In this article we conduct a comparative analysis of the Public Passenger Transport service systems in the cities of Curitiba, Brazil; Santiago de Chile, Chile; and Rosario, Argentina in order to compare and contrast similarities, differences and difficulties presented by these systems during the implementation stages of public policies. We bring in a systematization of policies, instruments and actions that allowed to manage the restructuring of the transport systems successfully, as well as their contributions to the development of a Public Transport Policy in Gran Mendoza.Fil: Marre, Mirta Elena. Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y SocialesFil: Barbosa, Cristina. Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y SocialesFil: Martínez, Lía. Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y Sociale

    Análisis de la afectación por vibraciones de la cantera La Roca en zonas cercanas a poblaciones

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    Trabajo de InvestigaciónEn este trabajo de investigacion presenta los análisis de la afectación por vibraciones de la cantera La Roca en zonas cercanas a poblaciones, con el objetivo de identificar los parámetros que influyen para el control de las vibraciones. Se realizaron visitas de campo a la cantera en la cual se realizaron las voladuras, obteniendo datos exactos por medio de equipos ideoneosINTRODUCCIÓN 1. GENERALIDADES 2. DESCRIPCION DE LAS PRUEBAS CON VOLADURA 3. TRABAJO DE CAMPO 4. RESULTADOS OBTENIDOS 5. ANALISIS DE RESULTADOS 6. CONCLUSIONES Y RECOMENDACIONES BIBLIOGRAFÌA ANEXOSPregradoIngeniero Civi

    Oralidad en el sistema acusatorio y sustentación de la apelación contra la sentencia en la ley 1395 de 2010

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    En este trabajo se examinan los alcances que para la oralidad y el modelo de ascendencia acusatoria tiene la posibilidad, introducida por la Ley 1395 de 2010, de sustentar por escrito la apelación contra la sentencia, y se sostiene que no desnaturaliza sino complementa el sistema procesal de la Ley 906 de 200

    Rodajas de piña preservadas por métodos combinados

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    Pineapple slices were treated by two combined methods, packaged and stored at room temperature. The first preservation method consisted of blanching pineapple slices at 100° C for two minutes followed by a cooling period of 1.5 minutes at room temperature. The slices were then immersed in a 50% sucrose solution with 1,000 ppm of potassium sorbate and 150 ppm of sodium bisulfite. The osmotic treatment was done at room temperature (28.5 ± 1.5° C) for 24 hours. The treated slices were removed from the osmotic solution, the excess syrup from the slices was removed, and the product was later packaged in sealed plastic bags. The final water activity values ranged between 0.95 and 0.97 for the packaged product. For the second preservation method, the pineapple slices were blanched in saturated steam for 12 minutes and stored at 12° C until processing by combined methods. Sucrose solutions (55 and 60° Brix) with four different concentrations of potassium sorbate (100, 200, 300, or 500 ppm) were used as osmotic solutions. The water activity was 0.91 after the osmotic process and 0.88 after hot air drying. A shelf life of at least 30 days was observed for product prepared with both preservation techniques, and the sensory characteristics noted were similar to those in a commercially canned product (Del Monte canned slices). The inhibitory effect of potassium sorbate on yeast and mold growth was significant for concentrations above 300 ppm.Se trataron rebanadas de pina con dos métodos combinados y se almacenaron a temperatura ambiente para evaluar su vida útil. El primer método de preservación consistió en escaldar la fruta a 100° C por dos minutos y luego enfriarla a temperatura ambiente (28.5 ± 1.5° C) por 1.5 minutos. Tras el enfriamiento se procedió a colocar las rodajas en almíbar al 50% de sacarosa con 1,000 ppm de sorbato de potasio y 150 ppm de bisulfito de sodio. El tratamiento osmótico se hizo a temperatura ambiente por 24 horas. Las rodajas se sacaron del almíbar y se empacaron en bolsas plásticas luego de escurrir la mayor parte del almíbar. La actividad de agua del producto empacado fluctuó entre 0.95 y 0.97. En el segundo método de preservación, las rebanadas de piña se escaldaron en vapor saturado por 12 minutos y se almacenaron en refrigeración (12° C) hasta su tratamiento por métodos combinados. Se usaron soluciones de sacarosa de 66 y 60° Brix con cuatro niveles de sorbato de potasio (100, 200, 300, 500 ppm) para la deshidratación osmótica de las rebanadas. Una vez en equilibrio, se removieron las rebanadas de la solución de sacarosa y se secaron parcialmente con aire caliente por una hora. El valor de actividad de agua fuego del tratamiento osmótico fue de 0.91 y bajó a 0.88 luego del secado parcial con aire caliente. Para ambos métodos de preservación se observó un período no menor a 30 días durante el cual las características sensoriales del producto compararon favorablemente con las de productos comerciales de piña enlatada (Del Monte). El efecto inhibidor de sorbato de potasio sobre los hongos y las levaduras fue evidente a concentraciones mayores de 300 ppm
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