306 research outputs found

    FIRST RECORDS OF RHYNOCRYPTID UNDERSTORY BIRDS IN THE CANOPY OF CHILEAN TEMPERATE RAINFORESTS

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    Abstract ∙ We documented the first observations of rhinocryptid birds in the canopy of a temperate rainforest in southern Chile. In the Bosque Pehuén Park, located in the southern Chilean Andes (39°42'S, 71°75'W), we installed camera traps in six old Nothofagus dombeyi trees, one per tree between 12 and 21 m above the forest floor. Traps were active from January to April 2017. The camera traps recorded three species of rhinocryptids in the canopy, between 12 and 14 m, Black-throated Huet-Huet (Pteroptochos tarnii), Chucao Tapaculo (Scelorchilus rubecula), and Magellanic Tapaculo (Scytalopus magellanicus). These records of rhinocryptids are unexpected since these species are currently believed to inhabit only on the forest floor and in the understory. This new information indicates that the canopy could occasionally provide food, shelter and nesting places for these birds.Resumen ∙ Primeros registros de rinocríptidos en el dosel de los bosques templados del sur de Chile En este trabajo documentamos las primeras observaciones de rinocríptidos en el dosel en los bosques templados del sur de Chile. En el parque Bosque Pehuén, en los Andes del sur (39°42'S, 71°75'W), se instalaron trampas cámara en seis árboles antiguos de Nothofagus dombeyi, una trampa por árbol, entre los 12 y los 21 m de altura. Las trampas estuvieron activas entre Enero y Abril de 2017. Las trampas cámara registraron tres especies de rinocríptidos entre los 12 y los 14 m de altura: Huet Huet (Pteroptochos tarnii), Chucao (Scelorchilus rubecula) y Churrín del sur (Scytalopus magellanicus). Estos registros de rinocríptidos son inesperados ya que estas especies se consideraban sólo como habitantes del suelo y del sotobosque. Esta nueva información indica que el dosel podría ocasionalmente proporcionar alimentos, refugio y lugares de anidación para estas aves

    Effect of γ-ethyl-γ-phenyl-butyrolactone (EFBL), anticonvulsant and hypnotic drug, on mouse brain catecholamine levels

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    γ-Ethyl-γ-phenyl-butyrolactone (EFBL) is a structural combination of the anticonvulsant γ-hydroxy-γ-ethyl-γ-phenylbutyramide (HEPB) and the hypnotic γ-butyrolactone (GBL), which inherits both properties. To clarify its mechanism of action, the effects of EFBL, GBL and HEPB on dopamine (DA) and noradrenaline (NA) brain levels were investigated. Influences of chlorpromazine, phenelzine and amino-oxyacetic acid were also studied. EFBL increased DA in a dose-dependent manner, remaining enhanced by 80 % over a period of 24 h and augmented NA by 54 % one hour after treatment. HEPB increased DA and NA approximately 2-fold after the first hour. GBL raised DA and NA after three and 24 h, resp. EFBL reversed chlorpromazine effects but potentiated those of phenelzine on DA. Amino-oxyacetic modified neither DA nor NA brain levels, not even in the presence of EFBL. The anticonvulsant and hypnotic properties of EFBL are attributed to its effect on presynaptic dopaminergic receptors and its lasting effect on ethyl and phenyl radicals that hinder its degradation. The results support the role of DA and NA in regulating seizure activity in the brain and indicate that EFBL offers a potential treatment for refractory epilepsy without complementary drugs and Parkinson’s disease, without the drawbacks of oral therapies

    Consumidores de frutos de Persea lingue (Lauraceae) en el sur de Chile y su efecto en la germinación de semillas

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    Frugivory is a common interaction mechanism between plants and animals in the temperate rainforest of southernSouth America. In this study, we examined primary dispersal and predation stages of Persea lingue (Ruiz et Pav.) Nees(Lauraceae), an endemic large-seeded tree of these forests. The main goal was to determine the identity of vertebrate seeddispersers of P. lingue, to distinguish legitimate seed dispersers, pulp consumers and seed predators, and their influenceon seed germination. In order to know which birds and small mammals were feeding P. lingue seeds, we observed 20P. lingue canopies, and live traps baited with P. lingue seeds were installed in fragment forests in south-central Chile.To determine whether birds could be legitimate dispersers of P. lingue, we collected regurgitated and fecal samples. Weexamined whether rodents removed the fruit pulp, the seeds, or the whole fruit. Additionally, we studied if seeds placedon the forest floor were removed by rodents. In a final experiment we conducted germination trials to establish whetherpulp removal (by birds, rodents, or artificially-removed) influenced germination rates. We found six bird species feedingon P. lingue seeds. None of them defecated intact seeds, but, Turdus falcklandii Quoy & Gaimard (Turdinae) and Xolmispyrope (Kittlitz) (Tyrannidae) regurgitated intact seeds. We captured five species of rodents in Sherman traps. Four of themleft intact seeds. We did not find any effect of the seed handling types (pulp consumption vs. seed regurgitation) in seedgermination rates. However, pulp removal was an important factor for germination success. We conclude that T. falcklandiiand X. pyrope are legitimate seed dispersers of P. lingue, since they swallow the whole fruit and regurgitate the intactseed. Abrothrix olivaceus (Waterhouse) (Cricetidae) and probably Oligoryzomys longicaudatus (Bennett) (Cricetidae) arepotential secondary dispersers of P. lingue seeds, as they prefer to eat the fruit pulp rather than the seeds.La dispersión de semillas por endozoocoría es uno de los principales mecanismos de interacción mutualista entre plantas yanimales en el bosque templado de Sudamérica. En este estudio indagamos acerca de los mecanismos de dispersión primariay estadios de depredación de semillas de Persea lingue (Ruiz et Pav.) Nees (Lauraceae), árbol endémico de estos bosques.El objetivo principal fue determinar la identidad de los vertebrados dispersores de semillas de P. lingue, distinguiendodispersores legítimos, de consumidores de pulpa y predadores de semillas, y determinar su efecto en la germinación. Serealizaron observaciones focales de la copa de adultos de P. lingue; además, se instalaron trampas Sherman cebadas confrutos de P. lingue en fragmentos de bosque en el valle central del centro-sur de Chile. Se colectaron muestras de fecasy semillas regurgitadas, se determinó cuáles especies de roedores consumieron la pulpa, las semillas o los frutos enterosen las trampas. Se examinó si hubo remoción de frutos y semillas desde el suelo. Se realizó un ensayo de germinaciónpara determinar si la forma de la remoción de la pulpa afecta las tasas de germinación. Registramos seis especies de avesconsumiendo frutos, ninguna defecó semillas, Turdus falcklandii Quoy & Gaimard (Turdinae) y Xolmis pyrope (Kittlitz)(Tyrannidae) regurgitaron semillas intactas. Capturamos cinco especies de roedores en las trampas, cuatro dejaron semillasintactas. No encontramos efecto del tipo de manipulación de las semillas en su germinación. La remoción de la pulpa fuedeterminante para el éxito de germinación. Concluimos que T. falcklandii y X. pyrope son dispersores legítimos de semillasde P. lingue. Abrothrix olivaceus (Waterhouse) (Cricetidae) y probablemente Oligoryzomys longicaudatus (Bennett)(Cricetidae) son potenciales dispersores secundarios, dada su marcada preferencia por la pulpa sobre las semillas

    Hábitos alimenticios y percepción de las personas hacia la Lechuza blanca (Tyto alba tuidara, J.E.Gray 1829) en un barrio urbano del sur de Chile: Implicancias para la conservación

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    People’s perception on birds of prey is heavily infl uenced by its intrinsic value, utility, myths and superstitions. In particular, negative perceptions may encourage poaching and persecution of these birds, affecting their conservation status. One nocturnal raptor species widely distributed across the world is the Barn Owl (Tyto alba, Tytonidae). In Chile, this species has been recorded and studied exclusively in rural and sub-urban areas. However, in the city of Valdivia Barn owls exist within the city boundaries. In this study we documented the feeding habits of Barn owls nesting in urban settings of Valdivia, and we analyze the opinions of local neighbors toward the owls. To characterize the diet of owls, we collected all pellets found around their nesting tree on a monthly basis between August 2010 and August 2011. We interviewed the neighbors using a questionnaire that included questions about the utility, ethical or aesthetic value of the owl and the tree where they nested. Our results indicate that the main prey of the Barn Owl was the Long-tailed Colilargo (Oligoryzomys longicaudatus).The neighbors’ perception was favorable to the Barn Owl primarily for aesthetic and ethical reasons, and not utilitarian reasons. Our results suggest that people perception in urban areas is different than in rural areas, where previous studies showed the prevalence of utilitarian values. This positive perception represents a great potential to promote conservation and environmental education in the city, creating a link between people and the natural elements they have in their environment.La percepción que tienen las personas frente a las rapaces está fuertemente infl uenciada por su valor intrínseco, por su utilidad, y por mitos y supersticiones. En particular, las percepciones negativas pueden fomentar la caza furtiva y la persecución de estas aves, afectando su estado de conservación. Una rapaz nocturna distribuida a nivel mundial es la lechuza blanca (Tyto alba, Tytonidae). En Chile, esta especie ha sido registrada y estudiada exclusivamente en zonasrurales y sub-urbanas. Sin embargo, en la ciudad de Valdivia existen lechuzas habitando dentro del perímetro urbano. En este trabajo documentamos la composición de especies de roedores consumidos por las lechuzas blancas dentro de un barrio urbano, y evaluamos la percepción de los vecinos sobre la presencia de lechuza blanca en su barrio. Para caracterizar la dieta de las lechuzas, recolectamos egagrópilas mensualmente entre agosto de 2010 y agosto de 2011. Para conocer la percepción de los vecinos, se elaboró un cuestionario que incluyó preguntas sobre el valor utilitario, ético o estético de la lechuza y del árbol donde nidifi caba. Nuestros resultados indican que la presa más consumida por la lechuza blanca fue el ratón colilarga (Oligoryzomys longicaudatus). La percepción de las personas resultó favorable hacia la lechuza blanca principalmente por razones estéticas y éticas, y no utilitarias. Nuestros resultados sugieren que la percepción de las personas en áreas urbanas es distinta de las zonas rurales, donde trabajos previos han mostrado que prevalecen los valores utilitarios. Esta percepción positiva podría representar un gran potencial para favorecer la conservación y la educación ambiental en la ciudad, generando un vínculo entre las personas y los elementos naturales que poseen en su entorno.&nbsp

    Computing Black Hole entropy in Loop Quantum Gravity from a Conformal Field Theory perspective

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    Motivated by the analogy proposed by Witten between Chern-Simons and Conformal Field Theories, we explore an alternative way of computing the entropy of a black hole starting from the isolated horizon framework in Loop Quantum Gravity. The consistency of the result opens a window for the interplay between Conformal Field Theory and the description of black holes in Loop Quantum Gravity.Comment: 9 page

    Serviceability conditions of pedestrian structures using a simplified moving mass model

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    Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.A simple mechanical model for pedestrian loading, consisting on a mass with a single degree of freedom that moves at constant speed along the footbridge, is presented. The footbrigde is modelled using a reduced number of beam 2D finite elements, simply supported at its ends. The dynamic interaction is ensured through direct requirement of contact conditions between the mass and the corresponding interpolated point in the beam. When the beam is massive enought, the results are similar to those obtained with models of mobile forces. However, if the beam is lightweight, the effect of the mass of the pedestrian can be significant, resulting in a more realistic modelling. The coupled model allows to study the interaction between the pedestrian and the structure and the results can be used to estimate by simulation the serviceability conditions of this type of slender structures under pedestrian loading

    The Mexican Patch-nosed Snake, Salvadora mexicana (Duméril, Bibron & Duméril, 1854; Squamata: Colubridae): a new state record for Zacatecas, Mexico, and a new prey species

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    Mexico, Zacatecas, Municipality of Valparaiso, ca. 2 km (airline) west of San Juan Capistrano, (22.637258° N; 104.118608° W [WGS84]; 1249 m elevation), 18 July 2017. Collected by Jorge A. Bañuelos-Alamillo. The snake was deposited in the Vertebrate Collection at Universidad Autónoma de Aguascalientes (CZUAA-REP-690); a photo voucher is also available at the San Diego Natural History Museum (SDSNH_HerpPC_05366). Adult female (SVL= 900 mm, TL= 380 mm), and had 17 midbody dorsal scales, 188 ventral scales, 106 subcaudals, nine supralabials, 11 infralabials, two loreal scales, one preocular, and three postoculars on both sides (Fig. 1-A). The snake was road-killed near a river within dry forest vegetation and had recently consumed an adult male Aspidoscelis gularis scalaris ingested headfirst.Asociación Herpetológica Argentin

    The Mexican Patch-nosed Snake, Salvadora mexicana (Duméril, Bibron & Duméril, 1854; Squamata: Colubridae): a new state record for Zacatecas, Mexico, and a new prey species

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    Mexico, Zacatecas, Municipality of Valparaiso, ca. 2 km (airline) west of San Juan Capistrano, (22.637258° N; 104.118608° W [WGS84]; 1249 m elevation), 18 July 2017. Collected by Jorge A. Bañuelos-Alamillo. The snake was deposited in the Vertebrate Collection at Universidad Autónoma de Aguascalientes (CZUAA-REP-690); a photo voucher is also available at the San Diego Natural History Museum (SDSNH_HerpPC_05366). Adult female (SVL= 900 mm, TL= 380 mm), and had 17 midbody dorsal scales, 188 ventral scales, 106 subcaudals, nine supralabials, 11 infralabials, two loreal scales, one preocular, and three postoculars on both sides (Fig. 1-A). The snake was road-killed near a river within dry forest vegetation and had recently consumed an adult male Aspidoscelis gularis scalaris ingested headfirst.Asociación Herpetológica Argentin

    Pre-notched dog bone small punch specimens for the estimation of fracture properties

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    In recent years, the pre-notched or pre-cracked small punch test (P-SPT) has been successfully used to estimate the fracture properties of metallic materials for cases in which there is not sufficient material to identify these properties from standard tests, such as CT or SENB specimens. The P-SPT basically consists of deforming a pre-notched miniature specimen, whose edges are firmly gripped by a die, using a high strength punch. The novelty of this paper lies in the estimation of fracture properties using dog-bone-shaped specimens with different confinement levels. With these specimens, three confinement variations have been studied. The results obtained enable the establishment of a variation of fracture properties depending on the level of confinement of each miniature specimen and selection of the most appropriate confinement for this goal.Ministry of Economy and Competitiveness of Spain through grant MAT2014-58738-C

    New record of Podilymbus podiceps (Linnaeus, 1758) (Podicipediformes, Podicipedidae) in the Patagonian region of southern Chile

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    We report a new record of Podilymbus podiceps (Linnaeus, 1758) in the southern Chilean Patagonia, 120 km south of previous records on the western side of the Andes, and more than 400 km south of their known distribution area on the eastern side of the Andes. This is the southernmost record of this species in Chile and one of the southernmost records worldwide, highlighting the vagrancy of this species in southern Patagonia
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