1,554 research outputs found

    Charge transport and vector meson dissociation across the thermal phase transition in lattice QCD with two light quark flavors

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    We compute and analyze correlation functions in the isovector vector channel at vanishing spatial momentum across the deconfinement phase transition in lattice QCD. The simulations are carried out at temperatures T/Tc=0.156,0.8,1.0,1.25T/T_c=0.156, 0.8, 1.0, 1.25 and 1.671.67 with Tc203T_c\simeq203MeV for two flavors of Wilson-Clover fermions with a zero-temperature pion mass of 270\simeq270MeV. Exploiting exact sum rules and applying a phenomenologically motivated ansatz allows us to determine the spectral function ρ(ω,T)\rho(\omega,T) via a fit to the lattice correlation function data. From these results we estimate the electrical conductivity across the deconfinement phase transition via a Kubo formula and find evidence for the dissociation of the ρ\rho meson by resolving its spectral weight at the available temperatures. We also apply the Backus-Gilbert method as a model-independent approach to this problem. At any given frequency, it yields a local weighted average of the true spectral function. We use this method to compare kinetic theory predictions and previously published phenomenological spectral functions to our lattice study.Comment: 28 pages, 6 figure

    Will Carbon Find a Home on the Range? A Monte Carlo Simulation

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    Rangeland Carbon Sequestration, Agribusiness, Agricultural and Food Policy, Land Economics/Use,

    The Effects of Scenic and Environmental Amenities on Agricultural Land Values

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    Ascribing land value solely to productive capacity does not accurately capture the impact environmental amenities provide on western land prices. Agricultural land prices in Wyoming are estimated using a hedonic price model and Geographic Information Sciences (GIS) data. These GIS measurements include on-parcel wildlife and fish habitat, viewscape attributes and distance to protected federal lands. A feasible generalized least squares (FGLS) approach is used to address both spatial autocorrelation and heteroscedasticity. The estimation is robust and highly significant. Results indicate that amenities as well as productivity are significant in explaining land values for the sample analyzed. Such information is useful for landscape management in the face of amenity threatening parcel fragmentation.Environmental Economics and Policy, Land Economics/Use,

    How digital transformation drives the evolution of self-managed teams?

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    The presented research was pursued within the framework of the Research Centre of Business Administration in The Bucharest University of Economic Studies, Romania. The research conducted for this paper is supposed to contribute to the wider academic discourse on the role of digital transformation for implementing self-managed work team structures. Against the background of strategic management considerations impacted by the latest wave of digitalization approaches, companies revisit organizational settings to exchange outdated command and control systems with more agile and customer-centric structures. While self-managed work structures have been around since the 1980s, impact factors of the digital era revive the topics relevance. In this context, the research paper combines an overview of the existing literature on the topic of digital transformation as well as the evolution of people management approaches with a case study on the challenges of introducing self-managed work team structures within a hierarchical set-up. While the first part of the paper focuses on assessing and qualifying the existing research conducted by international scholars and publishers, the second part is going to present the results of the quantitative and qualitative research conducted in a test case scenario in one of the leading German direct banks. Essentially, the results of the case study present new facets on the introduction of self-managed work teams and contribute to the overall value in terms of productivity and learning for organizations

    Linking ecosystem condition and ecosystem services: A methodological approach applied to European agroecosystems

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    Agriculture has been identified as one of the main drivers of environmental degradation in the European Union (EU). It can have negative impacts on air, water, soil and biodiversity. The condition of agroecosystems is affected by soil degradation, especially by soil erosion, which reduces agroecosystems' capacity to provide essential ecosystem services. Therefore, it is necessary to explore synergies and trade-offs between pressures, ecosystem condition and services to create relevant information for policy and decision-makers to implement sustainable response actions. As part of the EU environmental policy, the Mapping and Assessment of Ecosystems and their Services (MAES) Working Group developed appropriate concepts to assess and link ecosystem condition and services. This study aims to test the indicators proposed by MAES to assess ecosystem condition and link it with the ecosystem services provision. For this, we applied a suggested operational framework developed in the context of the Biodiversity Strategies 2020 and 2030 for the integrated assessment of agroecosystems and regulating ecosystem service control of erosion rates supply at European scale. We quantified and mapped indicators for ecosystem condition, environmental and anthropogenic pressures and soil erosion control. We explored the relationships between the respective indicators and the capacity of agroecosystems to control soil erosion across the different Environmental Zones (EZ). Our results indicate that, in general, European agroecosystems have a high capacity to control soil erosion with some variations within the EZ. Supply capacity is positively, negatively and not correlated with the various pressure and condition indicators. Management and climate indicators play a significant role in the assessment of this service. These results highlight that conservational management practices are fundamental to reduce soil loss and improve agroecosystem condition. However, the design and implementation of such management practices must consider regional and local landscape characteristics, agricultural practices and the needs and opportunities of stakeholders. © 2021 The Author(s

    The impact of soil erosion on soil-related ecosystem services: development and testing a scenario-based assessment approach

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    The ecosystem service (ES) approach usually addresses soil erosion as the regulating service control of erosion rates or soil retention. In addition to the assessment of this regulating ES, mitigated impacts on soil-related ES by preventing soil erosion can be assessed. This study presents a scenario-based approach for the assessment of the impact of soil erosion on soil-related ES. The assessment approach was tested in agricultural landscapes in Northern Germany, combining mapping and assessment of soil-related ES. In six scenarios, the degradation of soils due to soil erosion was simulated by the calculation of soil profile reductions. The scenarios represent two levels of impact with three time steps (+50, +100, +150 years). In the scenarios for the structural impact, the potential soil erosion rates were extrapolated into the future to generate spatially explicit information on degraded soils. In the scenarios for the mitigated impact, the actual soil erosion rates were extrapolated. Four soil-related ES were assessed for the initial state and the scenarios crop provision, water filtration, water flow regulation and fresh water provision. The comparison of the potential service supply of the four soil-related ES in the scenarios enabled the assessment of the long-term effect of the ES control of erosion rates. The mitigated reduction in the potential service supply for three of the considered ES (crop provision, water filtration, water flow regulation) is large and highlights the importance of sustainable soil management. Contrary to this, the ES fresh water provision benefits of erosion-induced soil profile reductions. © 2021, The Author(s)

    Assessment of the relationships between agroecosystem condition and the ecosystem service soil erosion regulation in Northern Germany

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    Ecosystems provide multiple services that are necessary to maintain human life. Agroecosystems are very productive suppliers of biomass-related provisioning ecosystem services, e.g. food, fibre, and energy. At the same time, they are highly dependent on good ecosystem condition and regulating ecosystem services such as soil fertility, water supply or soil erosion regulation. Assessments of this interplay of ecosystem condition and services are needed to understand the relationships in highly managed systems. Therefore, the aim of this study is twofold: First, to test the concept and indicators proposed by the European Union Working Group on Mapping and Assessment of Ecosystems and their Services (MAES) for assessing agroecosystem condition at a regional level. Second, to identify the relationships between ecosystem condition and the delivery of ecosystem services. For this purpose, we applied an operational framework for integrated mapping and assessment of ecosystems and their services. We used the proposed indicators to assess the condition of agroecosystems in Northern Germany and regulating ecosystem service control of erosion rates. We used existing data from official databases to calculate the different indicators and created maps of environmental pressures, ecosystem condition and ecosystem service indicators for the Federal State of Lower Saxony. Furthermore, we identified areas within the state where pressures are high, conditions are unfavourable, and more sustainable management practices are needed. Despite the limitations of the indicators and data availability, our results show positive, negative, and no significant correlations between the different pressures and condition indicators, and the control of erosion rates. The idea behind the MAES framework is to indicate the general condition of an ecosystem. However, we observed that not all proposed indicators can explain to what extent ecosystems can provide specific ecosystem services. Further research on other ecosystem services provided by agroecosystems would help to identify synergies and trade-offs. Moreover, the definition of a reference condition, although complicated for anthropogenically highly modified agroecosystems, would provide a benchmark to compare information on the condition of the ecosystems, leading to better land use policy and management decisions
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