574 research outputs found

    TESTING FOR EFFICIENCY: A POLICY ANALYSIS WITH PROBABILITY DISTRIBUTIONS

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    The study evaluates the efficiency of government intervention using a vertical structured model including imperfectly competitive agricultural input markets, the bread grain market, and the imperfectly competitive food industry. To test for policy efficiency the actually observed bread grain policy is compared to a hypothetical efficient policy. To account for the sensitivity of the results in regard to the model parameter values computer-intensive simulation procedures and surface response functions are utilized.agricultural policy, efficient combination of policy instruments, statistical policy analysis, Productivity Analysis,

    Was the Austrian agricultural policy least cost efficient?

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    The study evaluates the efficiency of government intervention using a vertical structured model including imperfectly competitive agricultural input markets, the bread grain market, and the imperfectly competitive food industry. To test for policy efficiency the actually observed bread grain policy is compared to a hypothetical efficient policy. To account for the sensitivity of the results in regard to the model parameter values computer-intensive simulation procedures and surface response functions are utilized.agricultural policy; efficient combination of policy instruments; statistical welfare analysis

    Agricultural adaptation to climate policies under technical change

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    This study uses a partial equilibrium model of the US agricultural sector to examine how technical progress and carbon price levels affect land management adaptation. We find that the climate policy range, over which a more extensive agriculture is preferred, decreases as crop yields increase. Second, technical progress with traditional crops offers less mitigation benefits than progress with mitigation options themselves. Third, while agricultural producers benefit from technical progress on energy crops, they fare worse if technical progress improves traditional crops and low carbon prices.Technical Change, Producer Adaptation, Agricultural Sector Model, Carbon Sequestration, Mathematical Programming, Climate Policy Simulation

    Optimization of a malachite green assay for detection of ATP hydrolysis by solubilized membrane proteins

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    We studied the activity of the fluorescently labeled membrane transporter MalGFK2, which transports maltose at the expense of ATP hydrolysis. We used a commercially available malachite green assay (SensoLyte MG phosphate assay kit; Anaspec) to quantify the liberated phosphate upon ATP hydrolysis. However, strong variations in phosphate concentration were measured when using the supplier’s handling protocol. We optimized the protocol, taking into account the effects mediated by glycerol, SDS, and fluorescent label on the sample. As a result we obtained highly reproducible phosphate concentration values under conditions optimal for solubilized membrane proteins

    The interdependencies between food and biofuel production in European agriculture - an application of EUFASOM

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    In the continuous quest to reduce anthropogenic emissions of carbon dioxide, the production and use of organically grown fuels in Europe has increased in importance in the recent past. However, the production of so-called biofuels is a direct competitor of agricultural food production for land, labor, water resources etc. with both land use options influencing each other depending on the respective boundary conditions defined by political regulations and economic considerations. In this study we will explore the economic and technical potentials of biofuels in Europe as well as the interdependencies between these two land use options for different economic incentives for biofuels using the European Forest and Agriculture Sector Optimization Model (EUFASOM). Key data on biodiesel and ethanol production have been gathered and are used for calibration of the model. The simulations extend until the year 2030, for which results are presented. Results indicate that moderate production targets of biofuels lead to an expansion of mainly the biodiesel production while more ambitious targets call for a focus on bioethanol. This has to do with the different levels of production efficiency depending on the production output. Growth of bioethanol feedstock is spread over entire Europe while the production of biodiesel feedstock occurs mainly in Central Europe.biodiesel, bioethanol, Europe, EUFASOM, modeling

    Is manganese-doped diamond a ferromagnetic semiconductor?

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    We use density-functional theoretical methods to examine the recent prediction, based on a mean-field solution of the Zener model, that diamond doped by Mn (with spin S=5/2) would be a dilute magnetic semiconductor that remains ferromagnetic well above room temperature. Our findings suggest this to be unlikely, for four reasons: (1) substitutional Mn in diamond has a low-spin S=1/2 ground state; (2) the substitutional site is energetically unfavorable relative to the much larger "divacancy" site; 3) Mn in the divacancy site is an acceptor, but with only hyperdeep levels, and hence the holes are likely to remain localized; (4) the calculated Heisenberg couplings between Mn in nearby divacancy sites are two orders of magnitude smaller than for substitutional Mn in germanium.Comment: 5 pages, 5 figure

    Constraining Cluster Physics with the Shape of X-ray Clusters: Comparison of Local X-ray Clusters versus LCDM Clusters

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    Simulations of cluster formation have demonstrated that condensation of baryons into central galaxies during cluster formation can drive the shape of the gas distribution in galaxy clusters significantly rounder, even at radii as large as half of the virial radius. However, such simulations generally predict stellar fractions within cluster virial radii that are ~2 to 3 times larger than the stellar masses deduced from observations. In this work we compare ellipticity profiles of clusters simulated with and without baryonic cooling to the cluster ellipticity profiles derived from Chandra and ROSAT observations in an effort to constrain the fraction of gas that cools and condenses into the central galaxies within clusters. We find that the observed ellipticity profiles are fairly constant with radius, with an average ellipticity of 0.18 +/- 0.05. The observed ellipticity profiles are in good agreement with the predictions of non-radiative simulations. On the other hand, the ellipticity profiles of the clusters in simulations that include radiative cooling, star formation, and supernova feedback (but no AGN feedback) deviate significantly from the observed ellipticity profiles at all radii. The simulations with cooling overpredict (underpredict) ellipticity in the inner (outer) regions of galaxy clusters. By comparing the simulations with and without cooling, we show that the cooling of gas via cooling flows in the central regions of simulated clusters causes the gas distribution to be more oblate in the central regions, but makes the outer gas distribution more spherical. We find that late-time gas cooling and star formation are responsible for the significantly oblate gas distributions in cluster cores, but the gas shapes outside of cluster cores are set primarily by baryon dissipation at high redshift z > 2.Comment: 10 pages, 6 figures, matching the published version in ApJ. Corrected missing reference in the arxiv versio

    The European Forest and Agriculture Optimisation Model -- EUFASOM

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    Land use is a key factor to social wellbeing and has become a major component in political negotiations. This paper describes the mathematical structure of the European Forest and Agricultural Sector Optimization Model. The model represents simultaneously observed resource and technological heterogeneity, global commodity markets, and multiple environmental qualities. Land scarcity and land competition between traditional agriculture, forests, nature reserves, pastures, and bioenergy plantations is explicitly captured. Environmental change, technological progress, and policies can be investigated in parallel. The model is well-suited to estimate competitive economic potentials of land based mitigation, leakage, and synergies and trade-offs between multiple environmental objectives.Land Use Change Optimization, Resource Scarcity, Market Competition, Welfare Maximization, Bottom-up Partial Equilibrium Analysis, Agricultural Externality Mitigation, Forest Dynamics, Global Change Adaptation, Environmental Policy Simulation, Integrated Assessment, Mathematical Programming, GAMS

    Comparison of Probability Distribution Function in Determining Minimum Annual and Monthly Streamflow

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    Este trabalho buscou fornecer embasamento a estudos de disponibilidade hídrica para a bacia hidrográfica do Arroio Belo, localizado no município de Caxias do Sul/RS. Para tanto, objetivou-se analisar a aplicação das funções de distribuição de probabilidade teórica Weibull, Normal, Log-Normal, Gumbel (mínimos), Log-Pearson e Pearson a dados de vazões mínimas de sete dias consecutivos. A análise teve dois enfoques: aplicação em dados anuais e, em seguida em dados mensais, considerando a sazonalidade. Para verificar a aderência das probabilidades estimadas às frequências observadas, aplicaram-se três testes: Kolmogorov-Smirnov, Anderson-Darling e Qui-Quadrado. Os resultados obtidos comprovam que a distribuição Log-Pearson III demonstra maior precisão na representação dos dados anuais da série histórica e alcança o melhor ajuste do valor da vazão mínima. Por outro lado, a análise em dados mensais, indicou a utilização da distribuição Pearson III, a qual apresentou maior adequabilidade aos dados de vazão mínima.  http://dx.doi.org/10.18226/23185279.v3iss2p42In this study it was aimed to provide the foundation studies of water availability in the Arroio Belo basin, in Caxias do Sul/RS. Therefore, this study aimed to analyze the application of Weibull, Normal, LogNormal, Gumbel (minimum), LogPearson and Pearson theoretical probability functions to data of minimum streamflows for seven consecutive days of the basin. The analysis had two approaches: application in annual data, and then on monthly data, considering seasonality. To verify the adherence to the estimated probabilities of observed frequencies, we applied three tests: Kolmogorov-Smirnov, Anderson-Darling and Chi-Squared. The results show that the Log-Pearson III distribution shows greater accuracy in representing the annual data of the series and reach the best fit of the minimum streamflow. The monthly data analysis indicated the use of the distribution Pearson III, which showed higher suitability to the minimum streamflow data.  http://dx.doi.org/10.18226/23185279.v3iss2p4
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