147 research outputs found

    Modelling the effects of land-use and land-cover change on water availability in the Jordan River region

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    Within the GLOWA Jordan River project, a first-time overview of the current and possible future land and water conditions of a major part of the Eastern Mediterranean region (ca. 100 000 km<sup>2</sup>) is given. First, we applied the hydrological model TRAIN to simulate current water availability (runoff and groundwater recharge) and irrigation water demand on a 1 km×1 km spatial resolution. The results demonstrate the scarcity of water resources in the study region, with extremely low values of water availability in the semi-arid and arid parts. Then, a set of four divergent scenarios on the future of water has been developed using a stakeholder driven approach. Relevant drivers for land-use/land-cover change were fed into the LandSHIFT.R model to produce land-use and land-cover maps for the different scenarios. These maps were used as input to TRAIN in order to generate scenarios of water availability and irrigation water demand for the region. For this study, two intermediate scenarios were selected, with projected developments ranging between optimistic and pessimistic futures (with regard to social and economic conditions in the region). Given that climate conditions remain unchanged, the simulations show both increases and decreases in water availability, depending on the future pattern of natural and agricultural vegetation and the related dominance of hydrological processes

    Exploring future agricultural development and biodiversity in Uganda, Rwanda and Burundi: a spatially explicit scenario-based assessment

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    Competition for land is increasing as a consequence of the growing demands for food and other commodities and the need to conserve biodiversity and ecosystem services. Land conversion and the intensification of current agricultural systems continues to lead to a loss of biodiversity and trade-offs among ecosystem functions. Decision-makers need to understand these trade-offs in order to better balance different demands on land and resources. There is an urgent need for spatially explicit information and analyses on the effects of different trajectories of human-induced landscape change in biodiversity and ecosystem services. We assess the potential implications of a set of plausible socio-economic and climate scenarios for agricultural production and demand and model-associated land use and land cover changes between 2005 and 2050 to assess potential impacts on biodiversity in Uganda, Rwanda and Burundi. We show that different future socio-economic scenarios are consistent in their projections of areas of high agricultural development leading to similar spatial patterns of habitat and biodiversity loss. Yet, we also show that without protected areas, biodiversity losses are higher and that expanding protected areas to include other important biodiversity areas can help reduce biodiversity losses in all three countries. These results highlight the need for effective protection and the potential benefits of expanding the protected area network while meeting agricultural production needs

    Spontaneous annihilation of high-density matter in the electroweak theory

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    In the presence of fermionic matter the topologically distinct vacua of the standard model are metastable and can decay by tunneling through the sphaleron barrier. This process annihilates one fermion per doublet due to the anomalous non-conservation of baryon and lepton currents and is accompanied by a production of gauge and Higgs bosons. We present a numerical method to obtain local bounce solutions which minimize the Euclidean action in the space of all configurations connecting two adjacent topological sectors. These solutions determine the decay rate and the configuration of the fields after the tunneling. We also follow the real time evolution of this configuration and analyze the spectrum of the created bosons. If the matter density exceeds some critical value, the exponentially suppressed tunneling triggers off an avalanche producing an enormous amount of bosons.Comment: 38 pages, 6 Postscript figure

    Ein implantierbares Telemetriesystem zur Impedanzspektroskopie

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugĂ€nglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Die kontinuierliche Überwachung des intrakorporalen Zustandes von Geweben beispielsweise zur Erkennung ischĂ€mischer VorgĂ€nge nach gefĂ€ĂŸchirurgischen Eingriffen oder im Rahmen der Rejektionsdiagnostik lĂ€ĂŸt sich durch bisher vorhandene Meßsysteme nur bedingt erreichen. Speziell die direkte Erfassung sensitiver Gewebeparameter ĂŒber einen lĂ€ngeren Zeitraum ohne Belastung fĂŒr den Patienten stellt in diesem Zusammenhang ein Problem dar. In der nachfolgenden Arbeit wird das Konzept eines implantierbaren Telemetriesystems vorgestellt, das die Bewertung des Gewebezustandes ĂŒber die Messung der frequenzabhĂ€ngigen Bioimpedanz ermöglicht. Besondere Beachtung wird der Auslegung und Umsetzung der einzelnen Systemkomponenten sowie der Vorstellung erster in vitro Messungen zur Evaluierung des Meßsystems geschenkt

    Prompt Multi-Gluon Production in High Energy Collisions from Singular Yang-Mills Solutions

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    We study non-perturbative parton-parton scattering in the Landau method using singular O(3) symmetric solutions to the Euclidean Yang-Mills equations. These solutions combine instanton dynamics (tunneling) and overlap (transition) between incoming and vacuum fields. We derive a high-energy solution at small Euclidean times, and assess its susequent escape and decay into gluons in Minkowski space-time. We describe the spectrum of the {\it outgoing} gluons and show that it is related through a particular rescaling to the Yang-Mills sphaleron explosion studied earlier. We assess the number of {\it incoming} gluons in the same configuration, and argue that the observed scaling is in fact more general and describes the energy dependence of the spectra and multiplicities at {\it all} energies. Applications to hadron-hadron and nucleus-nucleus collisions are discussed elsewhere

    Fermion sea along the sphaleron barrier

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    In this revised version we have improved the treatment of the top and bottom quark mass. This leads to slight changes of the numerical results, especially of those presented in Fig.4. The discussion of the numerical procedure and accuracy has been extended.Comment: 39 pages (LaTex) plus 5 figures (uuencoded postscript files); RUB-TPII-62/93, to appear in Phys.Rev.

    Estudo multicĂȘntrico comparativo de quatro diferentes tipos de sensores: atividade, acelerĂŽmetro, temperatura e perĂ­odo de prĂ©-ejeçao

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    Recentemente diferentes princĂ­pios tĂȘm sido utilizados para estimular o coraçao na tentativa de recuperar o dĂ©bito cardĂ­aco. Neste estudo multicĂȘntrico, foram comparadas as respostas Ă  estimulaçao por 4 tipos de sensores, sendo 3 tipos de resposta de alça aberta (atividade fĂ­sica, acelerĂŽmetro e temperatura venosa central) implantados em 30 (SSIR-8 e DDDR-22), 9 (SSIR-5 -e DDDR-4) e 12 (SSIR) pacientes respectivamente. Um outro sensor do tipo alça fechada, sensĂ­vel Ă s variaçoes do sistema nervoso autĂŽnomo, foi implantado em 57 pacientes, todos no modo DDDR. Os resultados obtidos durante a realizaçao de atividade fĂ­sica diĂĄria, de teste ergomĂ©trico e de Holter de 24 horas foram comparados, sendo possĂ­vel observar uma maior fidelidade na curva de resposta de freqĂŒĂȘncia frente a atividade fĂ­sica, nos pacientes submetidos Ă  estimulaçao de alça fechada

    Estudo multicĂȘntrico comparativo de quatro diferentes tipos de sensores: atividade, acelerĂŽmetro, temperatura e perĂ­odo de prĂ©-ejeçao

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    Recentemente diferentes princĂ­pios tĂȘm sido utilizados para estimular o coraçao na tentativa de recuperar o dĂ©bito cardĂ­aco. Neste estudo multicĂȘntrico, foram comparadas as respostas Ă  estimulaçao por 4 tipos de sensores, sendo 3 tipos de resposta de alça aberta (atividade fĂ­sica, acelerĂŽmetro e temperatura venosa central) implantados em 30 (SSIR-8 e DDDR-22), 9 (SSIR-5 -e DDDR-4) e 12 (SSIR) pacientes respectivamente. Um outro sensor do tipo alça fechada, sensĂ­vel Ă s variaçoes do sistema nervoso autĂŽnomo, foi implantado em 57 pacientes, todos no modo DDDR. Os resultados obtidos durante a realizaçao de atividade fĂ­sica diĂĄria, de teste ergomĂ©trico e de Holter de 24 horas foram comparados, sendo possĂ­vel observar uma maior fidelidade na curva de resposta de freqĂŒĂȘncia frente a atividade fĂ­sica, nos pacientes submetidos Ă  estimulaçao de alça fechada
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