Resumen El Parque Cueva de los Guácharos fue el primer parque nacional declarado en Colombia y, a pesar de su estratégica ubicación, poco se ha publicado sobre la biodiversidad del parque. Este estudio exploró la diversidad de los ensamblajes de aves en diferentes tipos de bosques (andinos, subandinos mixtos y subandinos de roble negro) y el estado de sucesión, que incluye bosques subandinos primarios y secundarios. Para ello, se realizaron puntos de conteo a lo largo de transectos, durante 382 días, entre los años 2005 y 2009. En este muestreo se reportan 202 especies de aves, representando 39 familias. Las comunidades de aves de los bosques subandinos presentaron mayor diversidad y similitud entre sí, independiente de su estado sucesional. La composición fue diferente en los bosques andinos (dominados por roble blanco, Quercus humboldtii) y de roble negro (dominados por Colombobalanus excelsa, Wettinia fascicularis y Motudaea colombiana). Por ejemplo, la especie dominante en los bosques andinos fue Colaptes rivolii y en los bosques de roble negro fue Zimmerius chrysops. Para los bosques subandinos, tanto primarios como secundarios, se compartieron varias especies en la lista de las más frecuentes: Henicorhina leucophrys, Rupicola peruvianus, Ocreatus underwoodii, Hypopyrrhus pyrohypogaster y Cyanocorax yncas. Este estudio -resalta la alta diversidad de los bosques subandinos, incluyendo bosques secundarios cercanos a bosques primarios protegidos. Esperamos que este trabajo sirva de base para el monitoreo futuro de comunidades de avifauna en el parque.

Abstract Cueva de los Guacharos was the first National Park created in Colombia, but few published information is available on its biological diversity. We used point counts along transects for a total of 382 days from 2005 to 2009, to estimate bird species richness and composition in Andean forests, Mixed Sub-Andean forests and Black Oak Sub-Andean forests. In addition, transects were undertaken in both primary and secondary Sub-Andean forests. We report the occurrence of 202 bird species from 39 families. Bird assemblages in mixed primary and secondary Sub- Andean Forest showed the highest species diversity, independent of the successional stage. A non-parametric ordination (based on species abundance) showed three main groupings: Andean forests (plants dominated by white oaks: Quercus humboldtii), Sub-Andean Black Oak forests (dominated by black oaks Colombobalanus excelsa, Wettinia fascicularis, and Matudaea colombiana), and mixed Sub-Andean forests (including both primary and secondary, with a variety of plant species). The most frequently registered bird species in Andean Forest was Calaptes rivolii. Zimmerius chrysops was the dominant species in Black Oak forests. In both mixed primary and secondary Sub-Andean forests the composition was similar with several species in the list of the most frequently observed: Henicorhina leucophrys, Rupicola peruvianus, Ocreatus underwoodii, Hypopyrrhus pyrohypogaster and Cyanocorax yncas. This study emphasizes that bird communities in Sub-Andean forests are highly diverse, and secondary forest show similar ensembles to primary forests, when they are protected and located near primary forests. We hope that this study will help to carry out future monitoring programs of bird species in the park.

Abstract Convergent beam diffraction (CBED) patterns of nanoparticles are possible. CBED of triangular prismatic shaped gold (Au) nanoparticle with focus on diffraction pattern symmetry and forbidden reflections observed along [111] and [112] zone axes are reported in this work. It is well known that the CBED patterns of nanoparticles of 30 nm or less in size only show bright kinematical discs. The dynamic contrast with Kikuchi and sharp HOLZ lines within the bright discs, as observed in CBED of volumetric materials, is well observed in particles larger of 500 nm in size. In addition, it is shown that the 1/3[422] and 1/2[311] weak forbidden reflections observed in the [111] and [112] electron diffraction patterns of these particles do not modify the symmetry of the CBED patterns, but they disappear as the size of the particle increases. The symmetry of the CBED patterns are always observed in concordance with the space group Fm3m (No. 225) of the Au unit cell. The possible explanations for observing forbidden reflections are the incomplete ABC stacking due to surface termination and the stacking faults in the fcc structure.

This work aimed to measure the effects of permanent and specific interference of S. polyacanthus on CP 74-2005 sugarcane cultivar in Monte Rico (27º21'S-65º36'W) (Tucumán province, Argentina). A complete randomized experimental design was carried out on a naturally infested sugarcane field. Each 64 m²-plot consisted of four ten-meter long furrows. The effects were measured at three infestation levels: high (more than 5 pl m-2), medium (1-4 pl m-2) and low (less than 1 pl m-2) . The measurements were taken on two central furrows in each plot. Height was taken by means of the average of ten measurements per infestation and per replication. Crop yield was evaluated by means of one sugarcane sample per plot, at the same place. The interference effects on height at different infestation degrees were highly significant in relation to the control, reaching 48.58% of losses in low infestation. In high infestation, there were significant losses of stem number, at the different levels, reaching 61.87%. Sugarcane yield per hectare presented a 43.89% loss under medium infestation. Sugar production presented 42.28% and 20.38% of losses in high and low infestation, respectively.

Se realizó este ensayo con el objeto de medir los efectos de la competencia permanente y especifica de S. polyacanthus sobre el cultivar CP 74-2005 en la localidad de Monte Rico (27º21'S-65º36'W, Tucumán-Argentina). El diseño experimental, completamente aleatorizado, se estableció en un cañaveral infestado naturalmente. Las parcelas fueron de 64 m² con cuatro surcos de diez metros de largo. Los efectos de la competencia fueron medidos en tres niveles de infestación: Alta (superior a 5 pl m-2), Media (1-4 pl m-2) y Baja (inferior a 1 pl m-2). Las mediciones se efectuaron sobre los dos surcos centrales de la parcela; para altura se analizó el promedio de diez mediciones por infestación y por repetición; y para producción de caña y de azúcar se trabajó con una muestra de caña por parcela, extraída del mismo sitio. Los efectos de la maleza en distinto grado de infestación sobre la altura del cañaveral fueron altamente significativos respecto del testigo obteniéndose pérdidas del 48,58% en baja infestación. En el número de tallos se encontraron pérdidas significativas en los diferentes niveles llegando a 61,87% en infestación alta. En la producción de caña por hectárea se produjeron perdidas de 43,89% en infestación media, mientras que en la producción de azúcar se registraron perdidas de 42,28 y 20,38% en infestación alta y baja respectivamente.