50 research outputs found

    Mejoras en la estimación de la frecuencia y magnitud de avenidas torrenciales mediante técnicas dendrogeomorfológicas

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    Para prevenir el riesgo de inundación, en el análisis científico de la peligrosidad asociada a las avenidas fluviales, clásicamente se han empleado métodos hidrológico-hidráulicos y, en menor medida, histórico-paleohidrológicos y geológico-geomorfológicos. Sin embargo, estas técnicas plantean enormes incertidumbres científicas por la disponibilidad de los datos de partida, su validez espacio-temporal, y su representatividad estadística. La Dendrogeomorfología es un conjunto de técnicas que, aprovechando fuentes de información registradas en las raíces, troncos y ramas de los árboles y arbustos ubicados en determinadas posiciones geomorfológicas (bancos de orilla, barras longitudinales, llanura de inundación, etc.), permite completar (e incluso suplir) el registro sistemático y paleohidrológico de avenidas torrenciales que han acontecido en esa corriente. En este artículo se propone investigar, se muestran los resultados-tipo y se discute sobre la aplicación y limitaciones de las fuentes de datos y los métodos científicos derivados del análisis dendrogeomorfológico. Para llevarlo a cabo, se sugiere una combinación de métodos de adquisición de datos en campo, estudios de laboratorio y análisis de datos en gabinete, con un plan de trabajo que contempla doce tareas o actividades: 1, caracterización geomorfológica; 2, caracterización florística; 3, muestreo de ejemplares: 4, adquisición de datos topográficos detallados; 5, preparación de las muestras; 6, conteo y medida de los anillos de crecimiento; 7, estudio anatómico e histológico; 8, sincronización de las series; 9, detección y datación de eventos; 10, modelación hidráulica de tramos; 11, análisis estadístico de caudales de avenida; y 12, cartografía de las áreas de peligrosidad por avenidas torrenciales y mapas de riesgo. - In order to prevent flood risks, scientific fluvial flood hazard analysis has been carried out traditionally with hydrologic and hydraulic methods, and secondarily, using palaeohydrological-historical and geological-geomorphological methods. Nonetheless, these techniques pose countless uncertainties due to the availability of the data, their spatio-temporal validity and their statistical representativeness. Dendrogeomorphology is a set of techniques that takes advantage of sources of information registered in roots, trunks and branches of trees or treelike bushes placed in certain geomorphological locations (such as banks, longitudinal bars, flood prone areas, etc.), that may be useful to complete the systematic registry or paleohydrologic data of torrential floods that have occurred in a certain stream. The aim of this paper is to research the usefulness and limitations of the data sources and methodologies derived from the dendrogeomorphological analysis. For accomplishing this objective a combination of methods is proposed, from data acquisition methods in field, laboratory studies, to data analysis. The schedule comprises twelve tasks: 1, geomorphologic characterization; 2, floristic characterization; 3, species sampling: 4, acquisition of detailed topographic data; 5, sample arrangement; 6, growth ring count and measurement; 7, hystologic and anatomic study; 8, series synchronization; 9, event detection and dating; 10, hydraulic reach modelling; 11, flow data statistical analysis; y 12, hazard and flood prone areas cartography and risk mapping

    Lactate signalling regulates fungal β-glucan masking and immune evasion

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    AJPB: This work was supported by the European Research Council (STRIFE, ERC- 2009-AdG-249793), The UK Medical Research Council (MR/M026663/1), the UK Biotechnology and Biological Research Council (BB/K017365/1), the Wellcome Trust (080088; 097377). ERB: This work was supported by the UK Biotechnology and Biological Research Council (BB/M014525/1). GMA: Supported by the CNPq-Brazil (Science without Borders fellowship 202976/2014-9). GDB: Wellcome Trust (102705). CAM: This work was supported by the UK Medical Research Council (G0400284). DMM: This work was supported by UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC/K000306/1). NARG/JW: Wellcome Trust (086827, 075470,101873) and Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology (097377). ALL: This work was supported by the MRC Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1).Peer reviewedPostprin

    Essential Role of TGF-β/Smad Pathway on Statin Dependent Vascular Smooth Muscle Cell Regulation

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    BACKGROUND: The 3-hydroxy-3-methylglutaryl CoA reductase inhibitors (also called statins) exert proven beneficial effects on cardiovascular diseases. Recent data suggest a protective role for Transforming Growth Factor-beta (TGF-beta) in atherosclerosis by regulating the balance between inflammation and extracellular matrix accumulation. However, there are no studies about the effect of statins on TGF-beta/Smad pathway in atherosclerosis and vascular cells. METHODOLOGY: In cultured vascular smooth muscle cells (VSMCs) statins enhanced Smad pathway activation caused by TGF-beta. In addition, statins upregulated TGF-beta receptor type II (TRII), and increased TGF-beta synthesis and TGF-beta/Smad-dependent actions. In this sense, statins, through Smad activation, render VSMCs more susceptible to TGF-beta induced apoptosis and increased TGF-beta-mediated ECM production. It is well documented that high doses of statins induce apoptosis in cultured VSMC in the presence of serum; however the precise mechanism of this effect remains to be elucidated. We have found that statins-induced apoptosis was mediated by TGF-beta/Smad pathway. Finally, we have described that RhoA inhibition is a common intracellular mechanisms involved in statins effects. The in vivo relevance of these findings was assessed in an experimental model of atherosclerosis in apolipoprotein E deficient mice: Treatment with Atorvastatin increased Smad3 phosphorylation and TRII overexpression, associated to elevated ECM deposition in the VSMCs within atheroma plaques, while apoptosis was not detected. CONCLUSIONS: Statins enhance TGF-beta/Smad pathway, regulating ligand levels, receptor, main signaling pathway and cellular responses of VSMC, including apoptosis and ECM accumulation. Our findings show that TGF-beta/Smad pathway is essential for statins-dependent actions in VSMCs

    Structure of a bacterial type III secretion system in contact with a host membrane in situ

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    Many bacterial pathogens of animals and plants use a conserved type III secretion system (T3SS) to inject virulence effector proteins directly into eukaryotic cells to subvert host functions. Contact with host membranes is critical for T3SS activation, yet little is known about T3SS architecture in this state or the conformational changes that drive effector translocation. Here we use cryo-electron tomography and sub-tomogram averaging to derive the intact structure of the primordial Chlamydia trachomatis T3SS in the presence and absence of host membrane contact. Comparison of the averaged structures demonstrates a marked compaction of the basal body (4 nm) occurs when the needle tip contacts the host cell membrane. This compaction is coupled to a stabilization of the cytosolic sorting platform– ATPase. Our findings reveal the first structure of a bacterial T3SS from a major human pathogen engaged with a eukaryotic host, and reveal striking ‘pump-action’ conformational changes that underpin effector injection

    A Net Energy Analysis of the Global Agriculture, Aquaculture, Fishing and Forestry System

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    The global agriculture, aquaculture, fishing and forestry (AAFF) energy system is subject to three unsustainable trends: (1) the approaching biophysical limits of AAFF; (2) the role of AAFF as a driver of environmental degradation; and (3) the long-term declining energy efficiency of AAFF due to growing dependence on fossil fuels. In response, we conduct a net energy analysis for the period 1971–2017 and review existing studies to investigate the global AAFF energy system and its vulnerability to the three unsustainable trends from an energetic perspective. We estimate the global AAFF system represents 27.9% of societies energy supply in 2017, with food energy representing 20.8% of societies total energy supply. We find that the net energy-return-on-investment (net EROI) of global AAFF increased from 2.87:1 in 1971 to 4.05:1 in 2017. We suggest that rising net EROI values are being fuelled in part by ‘depleting natures accumulated energy stocks’. We also find that the net energy balance of AAFF increased by 130% in this period, with at the same time a decrease in both the proportion of rural residents and also the proportion of the total population working in AAFF—which decreased from 19.8 to 10.3%. However, this comes at the cost of growing fossil fuel dependency which increased from 43.6 to 62.2%. Given the increasing probability of near-term fossil fuel scarcity, the growing impacts of climate change and environmental degradation, and the approaching biophysical limits of global AAFF, ‘Odum’s hoax’ is likely soon to be revealed

    Somos diversidad. Actividades para la formación de profesionales de la educación formal y no formal en diversidad sexual, familiar, corporal y de expresión e identidad de género

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    Este manual se presenta como una “caja de herramientas” donde acudir en busca de recursos y actividades didácticas para elaborar formaciones en diversidad sexual, familiar, corporal y de expresión e identidad de género, dirigidas a profesionales que trabajan con jóvenes. En este sentido, son materiales que se pueden adaptar a las necesidades de cada formación y a distintos niveles de conocimiento, tanto de los grupos participantes, como de la persona que dinamice las actividades y que son lo suficientemente flexibles para que puedan ser moldeados y utilizados según los recursos temporales y espaciales que presente cada propuestaformativa. “Somos diversidad” ofrece un total de 44 actividades articuladas en 5 módulos temáticos. Abrazar la diversidad como una oportunidad educativa Transformarse para transformar: afectividad, diferencia y diversidad Sexualidades Corporalidades, identidades y expresiones de género Diversidad familiar Cada módulo ofrece un índice inicial, una breve bienvenida donde se reflejan la justificación y objetivos del módulo, una serie de actividades y un apartado de bibliografía citada y consultada. En cada actividad se detalla su duración estimada, los objetivos propuestos, los recursos necesarios, las indicaciones para su desarrollo, y se aportan finalmente los materiales específicos necesarios para realizarlas. Este manual es el resultado de la actividad “Juventud y LGTBI+: abrazar la diversidad en la educación no formal y formal” dentro del Plan de Actividades Transnacionales (TCA) del programa Erasmus+: Juventud en Acción, organizada por el Injuve y el Grupo de Investigación “Antropología, Diversidad y Convivencia” de la Universidad Complutense de Madrid
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