43 research outputs found

    Estimating the Returns to Mangrove Conversion: Sustainable Management or Short Term Gain?

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    The purpose of this project is to estimate the total economic value of a mangrove ecosystem in part of the Gulf of Fonseca, El Salvador, and to develop a cost-benefit framework to compare the sustainable management of the forest with alternative use scenarios. The current management strategy is compared to its sustainable counterpart, and to the partial conversion of the mangrove ecosystem to semi-intensive aquaculture and salt ponds. A variety of different valuation techniques are used to assess the contribution of different products and services of the mangrove ecosystem. Among these techniques, a pseudo production function approach is used to calculate dose-response estimates of the impact of mangrove loss on the productivity of marine and estuarine fisheries. The valuation exercise yields the result that the sustainable management strategy enables more timber and fisheries benefits to be captured over a horizon of 56 years than do the other management options. This supports the view that the allocation of usufruct rights and the sanctioned conversion of mangrove forest to artificial shrimp ponds reduces the net benefits available to society, and that such policy failures accelerate the loss of biodiversity and compound existing market failures. The research was highly participatory and involved the community in the measurement and articulation of the value of the mangroves. As such, it is one of the first valuation exercises to incorporate a community definition of sustainable management one which reflects the revealed preference valuations of the community and which is in harmony with their management concerns.Resource /Energy Economics and Policy,

    Vínculos transnacionales: el caso de los salvadoreños en Estados Unidos

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    MRM2 and MRM3 are involved in biogenesis of the large subunit of the mitochondrial ribosome

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    Defects of the translation apparatus in human mitochondria are known to cause disease, yet details of how protein synthesis is regulated in this organelle remain to be unveiled. Ribosome production in all organisms studied thus far entails a complex, multistep pathway involving a number of auxiliary factors. This includes several RNA processing and modification steps required for correct rRNA maturation. Little is known about the maturation of human mitochondrial 16S rRNA and its role in biogenesis of the mitoribosome. Here we investigate two methyltransferases, MRM2 (also known as RRMJ2, encoded by FTSJ2) and MRM3 (also known as RMTL1, encoded by RNMTL1), that are responsible for modification of nucleotides of the 16S rRNA A-loop, an essential component of the peptidyl transferase center. Our studies show that inactivation of MRM2 or MRM3 in human cells by RNA interference results in respiratory incompetence as a consequence of diminished mitochondrial translation. Ineffective translation in MRM2- and MRM3-depleted cells results from aberrant assembly of the large subunit of the mitochondrial ribosome (mt-LSU). Our findings show that MRM2 and MRM3 are human mitochondrial methyltransferases involved in the modification of 16S rRNA and are important factors for the biogenesis and function of the large subunit of the mitochondrial ribosome

    Linear mitochondrial DNA is rapidly degraded by components of the replication machinery.

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    Emerging gene therapy approaches that aim to eliminate pathogenic mutations of mitochondrial DNA (mtDNA) rely on efficient degradation of linearized mtDNA, but the enzymatic machinery performing this task is presently unknown. Here, we show that, in cellular models of restriction endonuclease-induced mtDNA double-strand breaks, linear mtDNA is eliminated within hours by exonucleolytic activities. Inactivation of the mitochondrial 5'-3'exonuclease MGME1, elimination of the 3'-5'exonuclease activity of the mitochondrial DNA polymerase POLG by introducing the p.D274A mutation, or knockdown of the mitochondrial DNA helicase TWNK leads to severe impediment of mtDNA degradation. We do not observe similar effects when inactivating other known mitochondrial nucleases (EXOG, APEX2, ENDOG, FEN1, DNA2, MRE11, or RBBP8). Our data suggest that rapid degradation of linearized mtDNA is performed by the same machinery that is responsible for mtDNA replication, thus proposing novel roles for the participating enzymes POLG, TWNK, and MGME1

    T cell phenotypes in COVID-19 - a living review

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    COVID-19 is characterized by profound lymphopenia in the peripheral blood, and the remaining T cells display altered phenotypes, characterized by a spectrum of activation and exhaustion. However, antigen-specific T cell responses are emerging as a crucial mechanism for both clearance of the virus and as the most likely route to long-lasting immune memory that would protect against re-infection. Therefore, T cell responses are also of considerable interest in vaccine development. Furthermore, persistent alterations in T cell subset composition and function post-infection have important implications for patients’ long-term immune function. In this review, we examine T cell phenotypes, including those of innate T cells, in both peripheral blood and lungs, and consider how key markers of activation and exhaustion correlate with, and may be able to predict, disease severity. We focus on SARS-CoV-2-specific T cells to elucidate markers that may indicate formation of antigen-specific T cell memory. We also examine peripheral T cell phenotypes in recovery and the likelihood of long-lasting immune disruption. Finally, we discuss T cell phenotypes in the lung as important drivers of both virus clearance and tissue damage. As our knowledge of the adaptive immune response to COVID-19 rapidly evolves, it has become clear that while some areas of the T cell response have been investigated in some detail, others, such as the T cell response in children remain largely unexplored. Therefore, this review will also highlight areas where T cell phenotypes require urgent characterisation

    The role and uses of antibodies in COVID-19 infections: a living review

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    Coronavirus disease 2019 has generated a rapidly evolving field of research, with the global scientific community striving for solutions to the current pandemic. Characterizing humoral responses towards SARS-CoV-2, as well as closely related strains, will help determine whether antibodies are central to infection control, and aid the design of therapeutics and vaccine candidates. This review outlines the major aspects of SARS-CoV-2-specific antibody research to date, with a focus on the various prophylactic and therapeutic uses of antibodies to alleviate disease in addition to the potential of cross-reactive therapies and the implications of long-term immunity

    Migración internacional y protección social

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