Faint recombination lines in Galactic PNe with [WC] nucleus

We present spatially resolved high-resolution spectrophotometric data for the planetary nebulae PB8, NGC2867, and PB6. We have analyzed two knots in NGC2867 and PB6 and one in PB8. The three nebulae are ionized by [WC] type nuclei: early [WO] for PB6 and NGC2867 and [WC 5-6] in the case of PB8. Our aim is to study the behavior of the abundance discrepancy problem (ADF) in this type of PNe. We measured a large number of optical recombination (ORL) and collisionally excited lines (CEL), from different ionization stages (many more than in any previous work), thus, we were able to derive physical conditions from many different diagnostic procedures. We determined ionic abundances from the available collisionally excited lines and recombination lines. Based on both sets of ionic abundances, we derived total chemical abundances in the nebulae using suitable ionization correction factors. From CELs, we have found abundances typical of Galactic disk planetary nebulae. Moderate ADF(O++) were found for PB8 (2.57) and NGC2867 (1.63). For NGC2867, abundances from ORLs are higher but still consistent with Galactic disk planetary nebulae. On the contrary, PB8 presents a very high O/H ratio from ORLs. A high C/O was obtained from ORLs for NGC2867; this ratio is similar to C/O obtained from CELs and with the chemical composition of the wind of the central star, indicating that there was no further C-enrichment in the star, relative to O, after the nebular material ejection. On the contrary, we found C/O<1 in PB8. Interestingly, we obtain (C/O)ORLs/(C/O)CELs < 1 in PB8 and NGC2867; this added to the similarity between the heliocentric velocities measured in [OIII] and OII lines for our three objects, argue against the presence of H-deficient metal-rich knots coming from a late thermal pulse event.Comment: 25 pages, 13 Tables, 4 Figures Accepted for publication in A&A. First page is blank for obscure latex reason

Una prueba basada en rachas para simetría al rededor de una mediana específica

Este artículo presenta una prueba, basada en rachas, para simetría de una distribución continua alrededor de su mediana conocida. Estudios de Monte Carlo muestran que, para doce casos de la Familia de Distribuciones Lambda Generalizada (FDLG) las cuales proveen un amplio rango de distribuciones asimétricas, la prueba presentada es más potente que las pruebas propuestas por McWilliams(1990) o Castillo(1993) cuando la distribución de la que provienen los datos es asimétrica y posee ambas colas

Todo sobre... palma de aceite

Esta publicación contribuye a la solución de dudas que presenten productores, técnicos y estudiantes con respecto al cultivo de palma de aceite en Colombia en los temas de comercialización, cosecha, genética y mejoramiento, manejo de plagas y enfermedades, morfología y fisiología y manejo del cultivo.Palma-Elaeis guineensi

Insecto barrenador :nueva identificación taxonómica para el insecto barrenador (Palmelampius heinrichi) de los frutos del chontaduro (Bactris gasipaes).

En el artículo se presenta la breve historia de la incursión del insecto barrenador, las características y la identificación del insecto, las características morfológicas en el macho como la cabeza, antenas, pronoto, elitros patas genitalia y estructuras asociadas y el tamaño y en el caso de la hembra se tiene el tamaño y la identificación taxonómica de la cual se deriva la etimología del género Palmelampius.Chontaduro-Bactris gasipaes - Astrocaryu

Recent consequences of climate change have affected tree growth in distinct Nothofagus macrocarpa (DC.) FM Vaz & Rodr age classes in Central Chile

Forests play an important role in water and carbon cycles in semiarid regions such as the Mediterranean ecosystems. Previous research in the Chilean Mediterranean forests revealed a break point in 1980 in regional tree-ring chronologies linked to climate change. However, it is still unclear which populations and age classes are more affected by recent increases in drought conditions. In this study, we investigated the influence of recent variations in precipitation, temperature, and CO2 concentrations on tree growth of various populations and age classes of Nothofagus macrocarpa trees in Central Chile. We sampled 10 populations from five sites of N. macrocarpa through its whole geographic distribution in both Coastal and Andes ranges. We used standard dendrochronological methods to (i) group populations using principal component analysis, (ii) separate age classes (young, mature, and old trees), (iii) evaluate linear growth trends based on the basal area increment (BAI), and (iv) analyze the link between BAI and atmospheric changes using linear mixed-effects models. Results showed that young trees are more sensitive to climate variability. Regarding population grouping, we observed that all population clusters were sensitive to winter-spring precipitation, but only the Andes and Coastal populations were negatively correlated with temperature. The results of CO2 fertilization analyses were controversial and unclear. Since young trees from all population clusters reacted positively in the phase with an increase of atmospheric CO2 between 1980 and 2014, this behavior was not translated into growth for the last 15 years (2000-2014). However, it should be noted that the young trees of the highest elevation populations did not have a negative growth trend, so it seems that CO2 counteracted the negative effect of recent regional climate change (increase in temperature and precipitation decrease) in these population trees. Further studies are needed to assess the effects of climate variability over other ecological and physiological processes.Fil: Venegas González, Alejandro. Universidad Mayor.; ChileFil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Peña Rojas, Karen. Universidad de Chile; ChileFil: Hadad, Martín Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Aguilera Betti, Isabella. Pontificia Universidad Católica de Valparaíso; Chile. Universidad Austral de Chile; ChileFil: Muñoz, Ariel A.. Pontificia Universidad Católica de Valparaíso; Chil

Avances sobre el comportamiento de los híbridos de primer generación de retrocruzamiento entre palma americana (Elaeis oleifera) y palma africana (Elaeis guineensis).

El artículo presenta los materiales y los métodos, la presencia de enfermedades, las medidas del crecimiento, los registros de producción, el análisis de frutos y racimos, la calidad de aceite, el avance de resultados como las características vegetativas y parámetros de crecimiento, las características de producción y la reacción a enfermedades y las conclusiones

La memoria: documento expansivo de la información contable de naturaleza externa

Desde la publicación del PGC-90 se han aprobado distintos planes sectoriales que han supuesto adecuar, a cada una de estas realidades, las normas generales de elaboración de información contable de naturaleza, principalmente, externa. Los cambios introducidos han significado la incorporación de criterios de valoración alternativos, la creación o modificación de ciertas cuentas a utilizar de forma específica, la adecuación de los modelos de balance y cuenta de pérdidas y ganancias y, sobre todo, la incorporación de información adicional en la memoria, respecto de la exigida con carácter general en el PGC-90

Proxima Centauri b is not a transiting exoplanet

We report Spitzer Space Telescope observations during predicted transits of the exoplanet Proxima Centauri b. As the nearest terrestrial habitable-zone planet we will ever discover, any potential transit of Proxima b would place strong constraints on its radius, bulk density, and atmosphere. Subsequent transmission spectroscopy and secondary-eclipse measurements could then probe the atmospheric chemistry, physical processes, and orbit, including a search for biosignatures. However, our photometric results rule out planetary transits at the 200~ppm level at 4.5$~{\mu}m$, yielding a 3$\sigma$ upper radius limit of 0.4~R_\rm{\oplus} (Earth radii). Previous claims of possible transits from optical ground- and space-based photometry were likely correlated noise in the data from Proxima Centauri's frequent flaring. Follow-up observations should focus on planetary radio emission, phase curves, and direct imaging. Our study indicates dramatically reduced stellar activity at near-to-mid infrared wavelengths, compared to the optical. Proxima b is an ideal target for space-based infrared telescopes, if their instruments can be configured to handle Proxima's brightness.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in MNRA

Suitable conditions for natural regeneration in variable retention harvesting of southern Patagonian Nothofagus pumilio forests

Background: Variable retention (aggregated and dispersed retention) harvesting proposed for Nothofagus pumilio was designed for timber purposes and biodiversity conservation. Harvesting by opening canopy generates different microenvironments and creates contrasting conditions for seedling establishment, growth, and eco-physiology performance due to synergies (positives or negatives) with biotic and abiotic factors. This study evaluated the regeneration in different microenvironment conditions within managed stands during 5 years after harvesting. Remnant forest structure after harvesting and different microenvironments were characterized in managed stands, where 105 regeneration plots were measured (3 stands × 7 microenvironments × 5 replicas). We characterized the seedling bank, as well as growth and ecophysiology performance of the regeneration. Univariate and multivariate analyses were conducted for the comparisons. Results: Microenvironments offered different environmental conditions for natural regeneration (soil moisture and light availability). Seedling under debris and dicot plants showed better eco-physiological performance, establishment, and growth than plants growing under monocots or located in the dispersed retention without the protection of other understory plants. The most unfavorable microenvironment conditions were high canopy cover of remnant trees (inside the aggregates or close to trees in the dispersed retention) and heavily impacted areas (skidder extraction roads). Conclusions: Favorable microenvironments in the harvested areas will improve the natural recruitment, growth, and eco-physiology performance of the natural regeneration after harvesting. It is necessary to develop new silvicultural practices that decrease the unfavorable microenvironments (e.g., road density or excessive woody accumulation), to assure the success of the proposed silvicultural method.EEA Santa CruzFil: Toro Manríquez, Mónica D.R. Centro Austral de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Cellini, Juan Manuel. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Investigaciones en Maderas; ArgentinaFil: Lencinas, María Vanessa. Centro Austral de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Universidad Nacional de la Patagonia Austral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Peña Rojas, Karen A. Universidad de Chile. Facultad de Ciencias Forestales y de Conservación de la Naturaleza. Departamento de Silvicultura y Conservación de la Naturaleza; ChileFil: Martínez Pastur, Guillermo José. Centro Austral de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Criterios teóricos que sustentan la formación docente continua en Educación Parvularia chilena en y para la diversidad

Education in Chile calls for a look at diversity, understanding it through categories, variety and distinction. Thus, continuous training has given rise to the need to formulate theoretical criteria regarding Early Childhood Education in and for diversity. The methodology of this study adopted a qualitative approach of the interpretative-participatory field type, with the support of Grounded Theory and its Continuous Comparative Method. The techniques used were in-depth interviews, and participant observation. The key informants were five educators with more than five years of work experience in early childhood education in the Region of Los Lagos, Chile. The findings were obtained from the interpretation of the empirical situations. In this way, dialectics and actions of the educators were clarified, with information about knowledge and experiences orientated towards diversity. It is concluded that the theoretical criteria will allow the teacher training to be successful, in order to develop competences to achieve the attention of diversity.La educación en Chile reclama una mirada hacia la diversidad, entendiéndola a través de las categorías, variedad y distinción. Es así como desde la formación continua emerge la necesidad de formular criterios teóricos en educación parvularia en y para la diversidad. La metódica asumió un enfoque cualitativo bajo el tipo interpretativa-participativa de campo, con apoyo de la Teoría Fundamentada y su Método Comparativo Continuo. Las técnicas empleadas fueron entrevistas en profundidad y la observación participante. Los informantes claves fueron cinco educadoras con más de cinco años de experiencia laborando en Educación Inicial de la Región de Los Lagos, Chile. Los hallazgos se obtuvieron de la interpretación de las situaciones empíricas, de este modo se esclarecieron dialécticas y actuaciones de las educadoras, con información sobre conocimientos y experiencias orientadoras hacia la diversidad. Se concluye que los criterios teóricos permitirán de manera acertada la formación del docente para desarrollar competencias para lograr la atención de la diversidad