459 research outputs found

    Watershed Forest Management Information System (WFMIS)

    Get PDF
    Maintenance of a sustainable clean water supply is critical for our future. However, watershed degradation is a common phenomenon around the world that leads to poor water quality. In order to protect water resources, the Watershed Forest Management Information System (WFMIS), was developed as an extension of ArcGIS® and is described in this paper. There are three submodels to address nonpoint source pollution mitigation, road system management, and silvicultural operations, respectively. The Watershed Management Priority Indices (WMPI) is a zoning approach to prioritize critical areas for conservation and restoration management. It meets the critical need to spatially differentiate land cover and site characteristics within a watershed to quantify their relative influence on overall water quality. The Forest Road Evaluation System (FRES) is a module to evaluate road networks in order to develop preventive management strategies. The Harvest Schedule Review System (HSRS) is a module to analyze and evaluate multi-year and multi-unit forest harvesting to assist in the reduction of impact on water yield and associated changes in water quality. The WFMIS utilizes commonly available spatial data and has user friendly interfaces to assist foresters and planners to manage watersheds in an environmentally healthy way. Application examples of each submodel are presented

    Comparaison de la performance du point de vue empirique de systèmes de demandes alternatifs

    Get PDF
    Dans ce papier, quatre versions de systèmes de demande différentiels sont comparés sur le plan empirique : le système de Rotterdam, une version du système de demande quasi idéal (Almost Ideal Demand), le système du Bureau Central des Statistiques (CBS) et le système NBR. Ces systèmes possèdent des points en commun au niveau des variables explicatives, mais diffèrent sur le plan de la transformation non linéaire de la variable endogène. La méthode de McAleer (1983) du test par addition de variables dans le cas d’une équation est cette fois appliquée à des vecteurs d’équations dans lesquelles les variables dépendantes du système sont sujettes à des transformations non linéaires. Une caractéristique intéressante dans la procédure du test par addition de variables réside dans le fait que la condition d’additivité peut s’appliquer de manière simple. Des données annuelles sur la période 1921-1981 aux Pays-Bas sont utilisées pour l’étude empirique et consistent en quatre groupes principaux de dépenses de consommation de ménages. Parmi les principaux résultats des estimations, on trouve qu’aucun système ne domine les autres pour expliquer les données. En comparant chaque système, on trouve que le système CBS est celui qui fournit les résultats les meilleurs, le système NBR les moins bons et les deux autres systèmes se positionnent entre ces deux extrêmes. Néanmoins, la spécification des coefficients de prix dans le système de Rotterdam donne de meilleurs résultats que dans le système AID.In this paper four versions of differential demand systems are compared empirically: namely, the Rotterdam system, a version of the Almost Ideal Demand (AID) system, the Central Bureau of Statistics (CBS) system, and the NBR system. These systems share common right-hand sides but differ in the non-linear data transformations of the endogenous variable. The variable addition testing method of McAleer (1983) for single equations is extended to vectors of equations in which the dependent variables of competing systems are subject to non-linear data transformations. An appealing feature of the variable addition testing procedure is that it accommodates the adding-up condition in a straight-forward manner. Annual data over the period 1921-1981 for The Netherlands for four major groups of consumer expenditure are used in the empirical application. It is found that no single system is dominant in explaining the data. Relatively speaking, the CBS system performs the best and the NBR system the worst, with the other two systems occupying intermediate positions. The specification of the price coefficients of the Rotterdam system appears to be empirically superior to that of the AID system

    Attractive Interaction Between Pulses in a Model for Binary-Mixture Convection

    Full text link
    Recent experiments on convection in binary mixtures have shown that the interaction between localized waves (pulses) can be repulsive as well as {\it attractive} and depends strongly on the relative {\it orientation} of the pulses. It is demonstrated that the concentration mode, which is characteristic of the extended Ginzburg-Landau equations introduced recently, allows a natural understanding of that result. Within the standard complex Ginzburg-Landau equation this would not be possible.Comment: 7 pages revtex with 3 postscript figures (uuencoded

    Bistability of Slow and Fast Traveling Waves in Fluid Mixtures

    Full text link
    The appearence of a new type of fast nonlinear traveling wave states in binary fluid convection with increasing Soret effect is elucidated and the parameter range of their bistability with the common slower ones is evaluated numerically. The bifurcation behavior and the significantly different spatiotemporal properties of the different wave states - e.g. frequency, flow structure, and concentration distribution - are determined and related to each other and to a convenient measure of their nonlinearity. This allows to derive a limit for the applicability of small amplitude expansions. Additionally an universal scaling behavior of frequencies and mixing properties is found. PACS: 47.20.-k, 47.10.+g, 47.20.KyComment: 4 pages including 5 Postscript figure

    Subharmonic bifurcation cascade of pattern oscillations caused by winding number increasing entrainment

    Full text link
    Convection structures in binary fluid mixtures are investigated for positive Soret coupling in the driving regime where solutal and thermal contributions to the buoyancy forces compete. Bifurcation properties of stable and unstable stationary square, roll, and crossroll (CR) structures and the oscillatory competition between rolls and squares are determined numerically as a function of fluid parameters. A novel type of subharmonic bifurcation cascade (SC) where the oscillation period grows in integer steps as n(2π)/(ω)n (2\pi)/(\omega) is found and elucidated to be an entrainment process.Comment: 7 pages, 4 figure

    New approaches in the management of multiple sclerosis

    Get PDF
    Multiple sclerosis (MS) is a central nervous system chronic inflammatory disease that is characterized by an extensive and complex immune response. Scientific advances have occurred in immunology, pathophysiology, and diagnostic and clinical assessment tools, and recent discovery of unique therapeutic targets has spurred numerous Phase II and Phase III clinical trials. Reductions in MS relapse rates and improvements in T2 or gadolinium-enhancing lesion burdens have been reported from Phase III trials that include fingolimod, alemtuzumab, cladribine, and rituximab. Promising Phase II trial data exist for teriflunomide, daclizumab, laquinimod, and fumarate. The optimism created by these favorable findings must be tempered with evaluation of the adverse effect profile produced by these new agents. Given the discovery of progressive multifocal leukoencephalopathy with the use of natalizumab, ongoing vigilance for rare and life-threatening reactions due to new agents should be paramount. Patients with MS often experience difficulty with ambulation, spasticity, and cognition. Recent clinical trial data from two Phase III dalfampridine-SR trials indicate certain patients receive benefits in ambulation. This article provides an overview of data from clinical trials of newer agents of potential benefit in MS

    Web-Based Spatial Decision Support System and Watershed Management with a Case Study

    Get PDF
    In order to maintain a proper balance between development pressure and water resources protection, and also to improve public participation, efficient tools and techniques for soil and water conservation projects are needed. This paper describes the development and application of a web-based watershed management spatial decision support system, WebWMPI. The WebWMPI uses the Watershed Management Priority Indices (WMPI) approach which is a prioritizing method for watershed management planning and it integrates land use/cover, hydrological data, soils, slope, roads, and other spatial data. The land is divided into three categories: Conservation Priority Index (CPI) land, Restoration Priority Index (RPI) land, and Stormwater Management Priority Index (SMPI) land. Within each category, spatial factors are rated based on their influence on water resources and critical areas can be identified for soil conservation, water quality protection and improvement. The WebWMPI has user-friendly client side graphical interfaces which enable the public to interactively run the server side Geographic Information System to evaluate different scenarios for watershed planning and management. The system was applied for Dry Run Creek watershed (Cedar Falls, Iowa, US) as a demonstration and it can be easily used in other watersheds to prioritize crucial areas and to increase public participation for soil and water conservation projects
    • …
    corecore