3,084 research outputs found

    Graph realizations constrained by skeleton graphs

    Get PDF
    In 2008 Amanatidis, Green and Mihail introduced the Joint Degree Matrix (JDM) model to capture the fundamental difference in assortativity of networks in nature studied by the physical and life sciences and social networks studied in the social sciences. In 2014 Czabarka proposed a direct generalization of the JDM model, the Partition Adjacency Matrix (PAM) model. In the PAM model the vertices have specified degrees, and the vertex set itself is partitioned into classes. For each pair of vertex classes the number of edges between the classes in a graph realization is prescribed. In this paper we apply the new {\em skeleton graph} model to describe the same information as the PAM model. Our model is more convenient for handling problems with low number of partition classes or with special topological restrictions among the classes. We investigate two particular cases in detail: (i) when there are only two vertex classes and (ii) when the skeleton graph contains at most one cycle.Comment: 19 page

    Hellenic Language and Culture Study in South Australian Schools: Parents' Perspectives

    Get PDF
    In this study, thirty parents of Hellenic background, born and educated in South Australia, share their current self-defined, bilingual and bicultural aspirations for the educational future of their children. The study examines how shifts in multicultural ideology affect the personal attitudes and perspectives of Australian born and educated parents of Hellenic background in regard to the bilingual and bicultural education of their children. The study is part of a continuous research project conducted in Adelaide from 1990–97 and in which a total of 90 participants were interviewed

    "The isolation and estimation of low molecular weight N-nitrosamines in biological materials"

    Get PDF
    Summary: Low molecular weight N-nitrosamines were detected by ultraviolet, infrared, nuclear magnetic resonance, mass spectral, thin-layer chromatographic and gas liquid chromatographic means. A method for the estimation of dimethylnitrosamine, diethylnitrosamine, ethal-n-propylnitrosamine and di-n-propylnitrosamine has been developed. The method involves the isolation of the nitrosamines in an aqueous distillate by freeze-drying. After extraction of the nitrosamines from the aqueous distillate by means of dichloromethane, their separation and quantitative estimation are achieved by gas liquid chromatography of the extract. The procedure can be extended down to the ppb range. Dimethylnitrosamine was isolated from an extract of Solanum incanum and identified by gas liquid chromatography on four different columns, infrared and nuclear magnetic resonance spectroscopy

    Agri-environmental Policy in the European Union: Who's in Charge?

    Get PDF
    The EU has argued that some agricultural subsidies are needed to provide the optimal amount of externalities (both positive and negative) produced by agriculture. The argument is that agriculture is "multifunctional" and externalities such as rural development and landscape would be underproduced, while some forms of pollution (such as nitrogen runoff) would be overproduced without government intervention. Meanwhile, the United States has raised the concern that multifunctionality is primarily an argument to transfer income to producers. One way to try and determine how much of these non-commodity payments are directed to externalities and how much is intended to distribute income to producers is to analyze the variation of the programs among the different member states of the EU. We estimate the degree to which environmental characteristics, agricultural characteristics and political economy variables determine the objective and amount of funding each member states uses to address environmental externalities (both positive and negative). Results indicate that little of the variance in agri-environmental expenditure can be explained by the difference in negative externalities, neither is there clear evidence that the payments are substituting for traditional agricultural subsidies. However, demand for environmental services and political variables seem to be the driving motivators behind a country's decision to spend money on agri-environmental programs.Environmental Economics and Policy,

    Agri-environmental Policy in the European Union: Who's in Charge?

    Get PDF
    European Union (EU) agri-environmental programmes (AEPs) represent a significant step in the region's efforts to decouple agricultural output from production and export subsidies. While AEPs comprise only a small share of EU agricultural support, they have two possible external impacts: 1) the composition of the EU's imports and exports may change as their producers become more market responsive; and 2) the WTO's Green Box (subsides considered minimally trade distorting and hence not disciplined) may become increasingly contentious. Our concern is with the drivers of AEPs in the EU and their implications for Canada.Environmental Economics and Policy,

    Causes of Multifunctionality: Externalities or Political Pressure?

    Get PDF
    The EU has argued that some agricultural subsidies are needed to provide the optimal amount of externalities (both positive and negative) produced by agriculture. The argument is that agriculture is "multifunctional" and externalities such as rural development and landscape would be underproduced, while some forms of pollution (such as nitrogen runoff) would be overproduced without government intervention. Meanwhile, the United States has raised the concern that multifunctionality is primarily an argument to transfer income to producers. In this paper, we discuss the motivation for the EU agri-environmental measures and empirically test for those underlying causes. We find that the programs are not targeted at those regions with the highest environmental need, but neither are they purely a substitute for traditional forms of agricultural subsidies. Demand for general environmental expenditure does influence agri-environmental expenditure as well, as does political structure.Environmental Economics and Policy,

    Big Coastal Physical Models – Controlling Variable Wave Boundaries

    Get PDF
    In coastal physical modelling, when bathymetries are complex and sea-states vary locally, it becomes necessary to combine all natural features in a single 3D physical model. This leads to physical models requiring long wave generation boundaries over which wave heights and directions could vary significantly. HR Wallingford has developed a novel wave generation method by which the wave height and direction along the paddle can be varied to match target wave parameters along the generation boundary. A recent large physical modelling study of a new port development in Chile, had a wave generation boundary of 5.2 km. The local bathymetry in the model needed to include a deep submarine canyon, which extended several km offshore and reached depths of over 150 m, which lead up to the breakwater of the new port. Due to the canyon, the wave heights along the wave generation boundary varied by 30-40 %. As part of the study, an investigation was carried out to determine the optimal calibration method; whether using variable wave heights and / or variable directions along the paddle front best matched the predicted design conditions at the structure toe. An ARTEMIS numerical model was used as part of the validation and calibration process
    • 

    corecore