16,540 research outputs found

    Rapid polynomial approximation in L2L_2-spaces with Freud weights on the real line

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    The weights Wα(x)=exp(xα)W_\alpha(x)=\exp{(-|x|^{\alpha})} (α>1)(\alpha>1) form a subclass of Freud weights on the real line. Primarily from a functional analytic angle, we investigate the subspace of L2(R,Wα2(x)dx)L_2(\mathbb R, W_\alpha^2(x)\,dx) consisting of those elements that can be rapidly approximated by polynomials. This subspace has a natural Fr\'echet topology, in which it is isomorphic to the space of rapidly decreasing sequences. We show that it consists of smooth functions and obtain concrete results on its topology. For α=2\alpha=2 there is a complete and elementary description of this topological vector space in terms of the Schwartz functions.Comment: 18 page

    First performance evaluation of a Multi-layer Thick Gaseous Electron Multiplier with in-built electrode meshes - MM-THGEM

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    We describe a new micro-pattern gas detector structure comprising a multi-layer hole-type multiplier (M-THGEM) combined with two in-built electrode meshes: the Multi-Mesh THGEM-type multiplier (MM-THGEM). Suitable potential differences applied between the various electrodes provide an efficient collection of ionization electrons within the MM-THGEM holes and a large charge avalanche multiplication between the meshes. Different from conventional hole-type multipliers (e.g. Gas Electron Multipliers - GEMs, Thick Gas Electron Multipliers - THGEMs, etc.), which are characterized by a variable (dipole-like) field strength inside the avalanche gap, electrons in MM-THGEMs are largely multiplied by a strong uniform field established between the two meshes, like in the parallel-plate avalanche geometry. The presence of the two meshes within the holes allows for the trapping of a large fraction of the positive ions that stream back to the drift region. A gas gain above 10^5 has been achieved for single photo-electron detection with a single MM-THGEM in Ar/(10%)CH4 and He/(10%)CO2, at standard conditions for temperature and pressure. When the MM-THGEM is coupled to a conventional THGEM and used as first cascade element, the maximum achievable gains reach values above 10^6 in He/(10%)CO2, while the IBF approaches of 1.5% in the case of optimum detector-bias configuration. This IBF value is several times lower compared to the one obtained by a double GEM/THGEM detector (5-10%), and equivalent to the performance attained by a Micromegas detector.Comment: 11 pages, 8 figures. Submitted to JINS

    Partial and Total Ideals of Von Neumann Algebras

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    A notion of partial ideal for an operator algebra is a weakening the notion of ideal where the defining algebraic conditions are enforced only in the commutative subalgebras. We show that, in a von Neumann algebra, the ultraweakly closed two-sided ideals, which we call total ideals, correspond to the unitarily invariant partial ideals. The result also admits an equivalent formulation in terms of central projections. We place this result in the context of an investigation into notions of spectrum of noncommutative CC^*-algebras.Comment: 14 page

    The Allocation of Resources by Interest Groups: Lobbying, Litigation and Administrative Regulation

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    One of the central concerns about American policy making institutions is the degree to which political outcomes can be influenced by interested parties. While the literature on interest group strategies in particular institutions - legislative, administrative, and legal - is extensive, there is very little scholarship which examines how the interdependencies between institutions affects the strategies of groups. In this paper we examine in a formal theoretical model how the opportunity to litigate administrative rulemaking in the courts affects the lobbying strategies of competing interest groups at the rulemaking stage. Using a resource-based view of group activity, we develop a number of important insights about each stage that cannot be observed by examining each one in isolation. We demonstrate that lobbying effort responds to the ideology of the court, and the responsiveness of the court to resources. In particular, (1) as courts become more biased toward the status quo, interest group lobbying investments become smaller, and may be eliminated all together, (2) as interest groups become wealthier, they spend more on lobbying, and (3) as the responsiveness of courts to resources decreases, the effect it has on lobbying investments depends on the underlying ideology of the court

    Gaming in a benchmarking environment. A non-parametric analysis of benchmarking in the water sector

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    This paper discusses the use of benchmarking in general and its application to the drinking water sector. It systematizes the various classifications on performance measurement, discusses some of the pitfalls of benchmark studies and provides some examples of benchmarking in the water sector. After presenting in detail the institutional framework of the water sector of the Belgian region of Flanders (without benchmarking experiences), Wallonia (recently started a public benchmark) and the Netherlands (introduced already in 1997 a public benchmark), we non-parametrically measure the productivity gains by the use of a dynamic Malmquist index. The three regions, each at a different stage of the benchmarking circle, exhibit different performance trends. The ‘carrot’ and the ‘stick’ of benchmarking seem to offer an effective incentive to trigger performance. In addition, the Malmquist decompositions provide some evidence on the ‘gaming’ of the stakeholders by the water utilities.Benchmarking; gaming; Malmquist decomposition; regulation; water sector

    The Allocation of Resources by Interest Groups: Lobbying, Litigation and Administrative Regulation

    Get PDF
    One of the central concerns about American policy-making institutions is the degree to which political outcomes can be influenced by interested parties. While the literature on interest group strategies in particular institutions - legislative, administrative, and legal is extensive, there is very little scholarship which examines how the interdependencies between institutions affects the strategies of groups. In this paper we examine in a formal theoretical model, how the opportunity to litigate administrative rulemaking in the courts affects the lobbying strategies of competing interest groups at the rulemaking stage. Using a resource-based view of group activity, we develop a number of important insights about each stage - which cannot be observed by examining each one in isolation. We demonstrate that lobbying effort responds to the ideology of the court, and the responsiveness of the court to resources. In particular, 1) as courts become more biased toward the status quo, interest group lobbying investments become smaller, and may be eliminated all together, 2) as interest groups become wealthier, they spend more on lobbying, and 3) as the responsiveness of courts to resources decreases, the effect it has on lobbying investments depends on the underlying ideology of the court.
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