341 research outputs found

    Integrated environmental modelling: achieving the vision

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    Integrated environmental modelling (IEM) is a recent phenomenon that offers the opportunity to solve complex environmental problems. Whilst it has made great strides in recent years, there are still challenges to be met before IEM is universally accepted and used. This paper describes the current state of IEM and sets out a roadmap for achieving its full potential. A multidisciplinary, multi-agency approach will be required, the main goals of which are to: (1) raise awareness and build confidence in IEM; (2) ensure availability and accessibility of IEM techniques, tools and standards; (3) establish a minimum set of standards; (4) build the IEM skills base; (5) establish an underpinning research and development (R&D) programme; (6) co-ordinate and promote collaboration; and (7) foster IEM use by government, industry and the public. Once these goals have been achieved, then IEM can be deployed to help resolve currently intractable environmental issues, and the IEM methodology can be transferred to other fields

    Introductory overview: the OpenMI 2.0 standard for integrating numerical models

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    The purpose of this paper is to introduce, explain and promote the Open Modelling Interface (OpenMI) version 2.0 standard for coupling environmental numerical models (simulations of environmental processes). It is intended to be accessible to readers of all levels of experience. During recent decades it has been recognised that the environment is made up of a complex set of interconnected processes. Therefore, understanding the environment requires not only understanding of the processes in isolation, but also the interactions between these processes. Traditional methods of simulating such environmental interactions have included passing the outputs of one numerical model into another or creating a single ‘super-model’ covering a variety of processes. OpenMI provides a standard method which could be applied to independent numerical model components allowing them to exchange data and therefore influence one another. This is achieved without fundamental changes to the core of the components themselves

    Universality in percolation of arbitrary Uncorrelated Nested Subgraphs

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    The study of percolation in so-called {\em nested subgraphs} implies a generalization of the concept of percolation since the results are not linked to specific graph process. Here the behavior of such graphs at criticallity is studied for the case where the nesting operation is performed in an uncorrelated way. Specifically, I provide an analyitic derivation for the percolation inequality showing that the cluster size distribution under a generalized process of uncorrelated nesting at criticality follows a power law with universal exponent γ=3/2\gamma=3/2. The relevance of the result comes from the wide variety of processes responsible for the emergence of the giant component that fall within the category of nesting operations, whose outcome is a family of nested subgraphs.Comment: 5 pages, no figures. Mistakes found in early manuscript have been remove

    Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (agora)

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    Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with app1133132sem informaçãosem informaçã

    The pressure of QCD at finite temperatures and chemical potentials

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    The perturbative expansion of the pressure of hot QCD is computed here to order g^6ln(g) in the presence of finite quark chemical potentials. In this process all two- and three-loop one-particle irreducible vacuum diagrams of the theory are evaluated at arbitrary T and mu, and these results are then used to analytically verify the outcome of an old order g^4 calculation of Freedman and McLerran for the zero-temperature pressure. The results for the pressure and the different quark number susceptibilities at high T are compared with recent lattice simulations showing excellent agreement especially for the chemical potential dependent part of the pressure.Comment: 35 pages, 6 figures; text revised, one figure replace
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