752 research outputs found

    La protección de los bosques, conservación y políticas estatales

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    SELVICULTURA CHILENA. Reglamentacion sobre el corte i conservación de los bosques._ Memoria presentada al certamen abirto en 1865 por la Facultad de Ciencias Físicas, por el injeniero don T. Mostardi‑Fioretti.   &nbsp

    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

    Toward integrated analysis of human impacts on forest biodiversity: lessons from Latin America.

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    Although sustainable forest management (SFM) has been widely adopted as a policy and management goal, high rates of forest loss and degradation are still occurring in many areas. Human activities such as logging, livestock husbandry, crop cultivation, infrastructural development, and use of fire are causing widespread loss of biodiversity, restricting progress toward SFM. In such situations, there is an urgent need for tools that can provide an integrated assessment of human impacts on forest biodiversity and that can support decision making related to forest use. This paper summarizes the experience gained by an international collaborative research effort spanning more than a decade, focusing on the tropical montane forests of Mexico and the temperate rain forests of southern South America, both of which are global conservation priorities. The lessons learned from this research are identified, specifically in relation to developing an integrated modeling framework for achieving SFM. Experience has highlighted a number of challenges that need to be overcome in such areas, including the lack of information regarding ecological processes and species characteristics and a lack of forest inventory data, which hinders model parameterization. Quantitative models are poorly developed for some ecological phenomena, such as edge effects and genetic diversity, limiting model integration. Establishment of participatory approaches to forest management is difficult, as a supportive institutional and policy environment is often lacking. However, experience to date suggests that the modeling toolkit approach suggested by Sturvetant et al. (2008) could be of value in such areas. Suggestions are made regarding desirable elements of such a toolkit to support participatory-research approaches in domains characterized by high uncertainty, including Bayesian Belief Networks, spatial multi-criteria analysis, and scenario planning.Most of the research described here was undertaken in three projects supported by the European Commission (INCO programme), namely SUCRE (ERBIC18CT970146), BIOCORES (ICA4- CT-2001-10095), and ReForLan (INCO-DEV-3 N° 032132), and three Darwin Initiative (DEFRA, UK Government) grants to the senior author. Additional funding was provided by a variety of sources within the partner countries. All sources of financial support are gratefully acknowledged

    Toward integrated analysis of human impacts on forest biodiversity: lessons from Latin America.

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    Although sustainable forest management (SFM) has been widely adopted as a policy and management goal, high rates of forest loss and degradation are still occurring in many areas. Human activities such as logging, livestock husbandry, crop cultivation, infrastructural development, and use of fire are causing widespread loss of biodiversity, restricting progress toward SFM. In such situations, there is an urgent need for tools that can provide an integrated assessment of human impacts on forest biodiversity and that can support decision making related to forest use. This paper summarizes the experience gained by an international collaborative research effort spanning more than a decade, focusing on the tropical montane forests of Mexico and the temperate rain forests of southern South America, both of which are global conservation priorities. The lessons learned from this research are identified, specifically in relation to developing an integrated modeling framework for achieving SFM. Experience has highlighted a number of challenges that need to be overcome in such areas, including the lack of information regarding ecological processes and species characteristics and a lack of forest inventory data, which hinders model parameterization. Quantitative models are poorly developed for some ecological phenomena, such as edge effects and genetic diversity, limiting model integration. Establishment of participatory approaches to forest management is difficult, as a supportive institutional and policy environment is often lacking. However, experience to date suggests that the modeling toolkit approach suggested by Sturvetant et al. (2008) could be of value in such areas. Suggestions are made regarding desirable elements of such a toolkit to support participatory-research approaches in domains characterized by high uncertainty, including Bayesian Belief Networks, spatial multi-criteria analysis, and scenario planning.Most of the research described here was undertaken in three projects supported by the European Commission (INCO programme), namely SUCRE (ERBIC18CT970146), BIOCORES (ICA4- CT-2001-10095), and ReForLan (INCO-DEV-3 N° 032132), and three Darwin Initiative (DEFRA, UK Government) grants to the senior author. Additional funding was provided by a variety of sources within the partner countries. All sources of financial support are gratefully acknowledged

    Senda Darwin Biological Station: Long-term ecological research at the interface between science and society

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    Indexación: Web of Science; Scielo.La Estación Biológica Senda Darwin (EBSD) constituye un centro de investigación inmerso en el paisaje rural del norte de la Isla de Chiloé (42º S), donde fragmentos del bosque siempreverde original coexisten con praderas de uso ganadero, turberas de Sphagnum, matorrales sucesionales, plantaciones de Eucalyptus y otras formaciones de origen antropogénico. Desde 1994 hemos realizado estudios de largo plazo centrados en algunas especies de plantas (e.g., Pilgerodendron uviferum D. Don) y animales (e.g., Aphrastura spinicauda Gmelin, Dromiciops gliroides [Thomas]) catalogados como amenazados o escasamente conocidos y en ecosistemas nativos de importancia regional y global (e.g., turberas de Sphagnum, bosque Valdiviano y Nordpatagónico). Las investigaciones han considerado las respuestas de las especies y de los ecosistemas frente al cambio antropogénico del paisaje y cambio climático, así como los efectos de diferentes formas de manejo. Este escenario es semejante al de otras regiones de Chile y Latinoamérica lo que da generalidad a nuestros resultados y modelos. En este período, investigadores asociados a la EBSD han producido más de un centenar de publicaciones en revistas nacionales e internacionales y 30 tesis de pre y postgrado. Entendiendo el papel clave de los seres humanos en los procesos ecológicos de la zona rural, la EBSD ha desarrollado un programa de educación ecológica y vinculación del avance científico con la sociedad local y nacional. La integración de la EBSD a la naciente red de Sitios de Estudios Socio-Ecológicos de Largo Plazo en Chile consolidará y fortalecerá la investigación básica y aplicada que realizamos para proyectarla hacia la siguiente década.Senda Darwin Biological Station (SDBS) is a field research center immersed in the rural landscape of northern Chiloé island (42º S), where remnant patches of the original evergreen forests coexist with open pastures, secondary successional shrublands, Sphagnum bogs, Eucalyptus plantations and other anthropogenic cover types, constituting an agricultural frontier similar to other regions in Chile and Latin America. Since 1994, we have conducted long-term research on selected species of plants (e.g., Pilgerodendron uviferum) and animals (e.g., Aphrastura spinicauda, Dromiciops glirioides) that are considered threatened, poorly known or important for their ecological functions in local ecosystems, and on ecosystems of regional and global relevance (e.g., Sphagnum bogs, North Patagonian and Valdivian rain forests). Research has assessed the responses of species and ecosystems to anthropogenic land-use change, climate change, and the impact of management. During this period, more than 100 scientific publications in national and international journals, and 30 theses (graduate and undergraduate) have been produced by scientists and students associated with SDBS. Because of our understanding of the key role that humans play in ecological processes at this agricultural frontier, since the establishment of SDBS we have been committed to creative research on the communication of science to society and ecological education. The integration of SDBS to the nascent Chilean network of long-term socio-ecological research will consolidate and strengthen basic and applied research to project our work into the next decade.http://ref.scielo.org/vbm4r

    Early in vitro response of macrophages and T lymphocytes to nanocrystalline hydroxyapatites

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    Hypothesis: Synthetic hydroxyapatite (HA) and Si substituted hydroxyapatite (SiHA) are calcium phosphate ceramics currently used in the field of dentistry and orthopaedic surgery. The preparation of both biomaterials as polycrystalline solid pieces or grains formed by nanocrystallites has awakened a great interest to enhance the bioactive behavior due to the microstructural defects and the higher surface area. The study of the macrophage and lymphocyte behavior in contact with nanocrystalline HA and SiHA will allow to elucidate the immune response which conditions the success or rejection of these biomaterials. Experiments: HA and SiHA granules (with sizes of tens of microns) have been prepared by controlled aqueous precipitation avoiding subsequent high temperature sintering. HA and SiHA granules were constituted by crystallites smaller than 50 nm. The effects of both nanocrystalline materials on immune system have been evaluated with macrophages (main components of innate immune system) and T lymphocytes (specific cells of adaptive response) after short-term culture as in vitro models of the early immune response. Findings: Significant decreases of macrophage proliferation and phagocytic activity, increased production of inflammatory cytokines (IL-6, TNF-a) and T lymphocyte apoptosis, were induced by these nanocrystalline ceramics suggesting that, after in vivo implantation, they induce significant effects on immune responses, including an early activation of the innate immune system. (C) 2013 Elsevier Inc. All rights reserved

    Las razones de por qué Chile debe detener la importación del abejorro comercial Bombus terrestris (Linnaeus) y comenzar a controlarlo

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    The global pollination crisis is not only produced by loss of pollinators but also by their homogenization, both processes caused by humans. This crisis impacts the persistence of many native plants species worldwide. In this document we analyze the ecological impacts that warrant the prohibition of new income of commercial bumblebee, Bombus terrestris to Chile. This species is highly invasive, it has been banned in other countries, but in Chile its entry is allowed since 1997. Thousands of colonies and fertilized queens entered the country every year and expand throughout the rest of South America. We give eleven reasons to stop B. terrestris entry to Chile and start controlling it. We justify these reasons based on work done both in the country and outside of it. At the same time, through the conclusions, we mentioned what should be the steps to followed regarding the prohibition B. terrestris entry to Chile.La crisis mundial de polinización no solo es producida por la pérdida de polinizadores, sino también por su homogeneización, ambos procesos causados por el ser humano. En este documento analizamos los impactos ecológicos que justifi can la prohibición de nuevos ingresos del abejorro comercial Bombus terrestris a Chile. Esta especie es altamente invasiva y ha sido prohibida en otros países, pero en Chile se permite su ingreso desde 1997. Miles de colonias y reinas fertilizadas ingresan al país cada año y se expanden por el resto de Sudamérica. En este artículo entregamos once razones para detener los ingresos de B. terrestris a Chile y comenzar a controlarlo. Justifi camos estas razones en base al trabajo realizado tanto en el país como fuera de él. Al mismo tiempo, a través de las conclusiones, mencionamos cuáles deberían ser los pasos a seguir respecto a la prohibición de ingreso de B. terrestris a Chile

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe
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