249 research outputs found

    Diseño y gestión adaptativa de un programa de pagos por servicios ecosistémicos en Copán Ruinas, Honduras

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    This article presents a case study of development of a Payments for Ecosystem Services (PES) program related to drinking water in the city of Copán Ruinas, Honduras. The methodology used for the design and the implementation of this program is based on an integrated and adaptive management approach. It includes the following elements: general diagnostic, definition of objectives, analysis of enabling conditions, technical design, implementation and evaluation. This paper presents the empirical results of the application of this methodology and, in particular, highlights the application of a performance-based payment system to remunerate local peasants in accordance to their land use decisions.Este artículo presenta el desarrollo de una iniciativa de pagos por servicios ecosistémicos relacionados con la provisión de agua potable en la comunidad de Copán Ruinas, Honduras. La metodología para diseñar e implementar este programa se basa en un enfoque integral y de gestión adaptativa, compuesto por varios componentes: definición de objetivos y diagnóstico general, análisis de condiciones habilitadoras, diseño técnico del programa, implementación y evaluación. El artículo presenta la aplicación de este enfoque y los resultados obtenidos en términos del diseño e implementación inicial del programa de pagos. Un resultado particularmente interesante tiene que ver con la construcción de un sistema de pagos basados en desempeño en donde los finqueros reciben pagos diferenciados de acuerdo al tipo y cantidad de cambios que logran en los sistemas productivos. La idea es que los pagos envíen señales acerca de cuáles cambios y usos del suelo son más deseables en términos de mejoramiento de la calidad y disponibilidad de agua para consumo humano

    Solving the stellar 62Ni problem with AMS

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    An accurate knowledge of the neutron capture cross sections of 62,63Ni is crucial since both isotopes take key positions which affect the whole reaction flow in the weak s process up to A=90. No experimental value for the 63Ni(n,gamma) cross section exists so far, and until recently the experimental values for 62Ni(n,gamma) at stellar temperatures (kT=30 keV) ranged between 12 and 37 mb. This latter discrepancy could now be solved by two activations with following AMS using the GAMS setup at the Munich tandem accelerator which are also in perfect agreement with a recent time-of-flight measurement. The resulting (preliminary) Maxwellian cross section at kT=30 keV was determined to be 30keV = 23.4 +/- 4.6 mb. Additionally, we have measured the 64Ni(gamma,n)63Ni cross section close to threshold. Photoactivations at 13.5 MeV, 11.4 MeV and 10.3 MeV were carried out with the ELBE accelerator at Forschungszentrum Dresden-Rossendorf. A first AMS measurement of the sample activated at 13.5 MeV revealed a cross section smaller by more than a factor of 2 compared to NON-SMOKER predictions.Comment: Proceedings of the 11th International Conference on Accelerator Mass Spectrometry in Rome, Sept. 14-19, 2008; to be published in Nucl. Instr. Meth.

    Anionic lipid nanoparticles preferentially deliver mRNA to the hepatic reticuloendothelial system

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    Lipid nanoparticles (LNPs) are the leading nonviral technologies for the delivery of exogenous RNA to target cells in vivo. As systemic delivery platforms, these technologies are exemplified by Onpattro, an approved LNP-based RNA interference therapy, administered intravenously and targeted to parenchymal liver cells. The discovery of systemically administered LNP technologies capable of preferential RNA delivery beyond hepatocytes has, however, proven more challenging. Here, preceded by comprehensive mechanistic understanding of in vivo nanoparticle biodistribution and bodily clearance, an LNP-based messenger RNA (mRNA) delivery platform is rationally designed to preferentially target the hepatic reticuloendothelial system (RES). Evaluated in embryonic zebrafish, validated in mice, and directly compared to LNP-mRNA systems based on the lipid composition of Onpattro, RES-targeted LNPs significantly enhance mRNA expression both globally within the liver and specifically within hepatic RES cell types. Hepatic RES targeting requires just a single lipid change within the formulation of Onpattro to switch LNP surface charge from neutral to anionic. This technology not only provides new opportunities to treat liver-specific and systemic diseases in which RES cell types play a key role but, more importantly, exemplifies that rational design of advanced RNA therapies must be preceded by a robust understanding of the dominant nano-biointeractions involved.Supramolecular & Biomaterials Chemistr

    Policy design for the Anthropocene

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    This is the author accepted manuscript. The final version is available from Nature Research via the DOI in this recordToday, more than ever, ‘Spaceship Earth’ is an apt metaphor as we chart the boundaries for a safe planet1. Social scientists both analyse why society courts disaster by approaching or even overstepping these boundaries and try to design suitable policies to avoid these perils. Because the threats of transgressing planetary boundaries are global, long-run, uncertain and interconnected, they must be analysed together to avoid conflicts and take advantage of synergies. To obtain policies that are effective at both international and local levels requires careful analysis of the underlying mechanisms across scientific disciplines and approaches, and must take politics into account. In this Perspective, we examine the complexities of designing policies that can keep Earth within the biophysical limits favourable to human life.Stockholm Resilience CentreBECC - Biodiversity and Ecosystem services in a Changing ClimateMistra Carbon Exi

    Species Tree Estimation for the Late Blight Pathogen, Phytophthora infestans, and Close Relatives

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    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based “supergene” approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred
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