2,386,532 research outputs found

    On the Effect of Technological Progress on Pollution: a New Distortion in an Endogenous Growth Model

    Get PDF
    We derive a model of endogenous growth with physical capital, human capital and technological progress through quality-ladders. We introduce welfare-decreasing pollution in the model, which can be reduced through the development of cleaner technologies. From the quantitative analysis of the model we show clear evidence that the new externality from technological progress to pollution considered in this model is sufficiently strong to induce underinvestment in R&D as an outcome of the decentralized equilibrium. An important policy implication of the main result of this article is a justification to subsidize the research in cleaner technologies.Environmental Pollution, R&D, Social Capital, Human Capital, Economic Growth

    Update on Partial-Wave Analysis

    Full text link
    Partial-wave analysis is one step in a process connecting experimental measurements to the N* states we are studying. Progress has been made in the area of `model-independent' analysis. However, more model-dependent approaches are needed to cover broader energy ranges. An example of the problems faced by these more ambitious analyses is given.Comment: 6 pages. Talk given at NSTAR2001, University of Mainz, Germany, March 7-10, 2001. To be published by World Scientifi

    Outer satellite atmospheres: Their extended nature and planetary interactions

    Get PDF
    Significant progress in model analysis of data for the directional features of the Io sodium cloud is reported and appears to provide some support for a satellite emission mechanism that is driven by a magnetospheric wind. A number of model calculations for the two dimensional intensity morphology of the Io sodium (region B) cloud are compared with six observations. Results of this comparison support tentative conclusions regarding the satellite emission conditions, the role of the plasma torus and the sodium atom escape flux. Progress in updating the Titan hydrogen torus model is also discussed

    Fixpoint Games on Continuous Lattices

    Get PDF
    Many analysis and verifications tasks, such as static program analyses and model-checking for temporal logics reduce to the solution of systems of equations over suitable lattices. Inspired by recent work on lattice-theoretic progress measures, we develop a game-theoretical approach to the solution of systems of monotone equations over lattices, where for each single equation either the least or greatest solution is taken. A simple parity game, referred to as fixpoint game, is defined that provides a correct and complete characterisation of the solution of equation systems over continuous lattices, a quite general class of lattices widely used in semantics. For powerset lattices the fixpoint game is intimately connected with classical parity games for Ό\mu-calculus model-checking, whose solution can exploit as a key tool Jurdzi\'nski's small progress measures. We show how the notion of progress measure can be naturally generalised to fixpoint games over continuous lattices and we prove the existence of small progress measures. Our results lead to a constructive formulation of progress measures as (least) fixpoints. We refine this characterisation by introducing the notion of selection that allows one to constrain the plays in the parity game, enabling an effective (and possibly efficient) solution of the game, and thus of the associated verification problem. We also propose a logic for specifying the moves of the existential player that can be used to systematically derive simplified equations for efficiently computing progress measures. We discuss potential applications to the model-checking of latticed Ό\mu-calculi and to the solution of fixpoint equations systems over the reals

    Social and Technological Efficiency of Patent Systems

    Get PDF
    This article develops an evolutionary model of industry dynamics in order to carry out a richer theoretical analysis of the consequences of a stronger patent system. The first results obtained in our article are rather consistent with the anti-patent arguments and they do not favour the case for a stronger patent system: higher social welfare and technical progress are observed in our model in industries with milder patent systems (lower patent height and patent life).Innovation, technical progress, patent system, Intellectual property rights,

    Rigorous results concerning the Holstein--Hubbard model

    Get PDF
    The Holstein model has been widely accepted as a model comprising electrons interacting with phonons; analysis of this model's ground states was accomplished two decades ago. However, the results were obtained without completely taking repulsive Coulomb interactions into account. Recent progress has made it possible to treat such interactions rigorously; in this paper, we study the Holstein--Hubbard model with repulsive Coulomb interactions. The ground state properties of the model are investigated; in particular, the ground state of the Hamiltonian is proven to be unique for an even number of electrons on a bipartite connected lattice. In addition, we provide a rigorous upper bound on charge susceptibility.Comment: 42 pages, Title changed, Major improvements, to appear, Annales Henri Poincar

    Theoretical Overview of Lorentz and CPT Violation

    Full text link
    In this talk, I discuss some recent theoretical progress concerning the Lorentz- and CPT-violating extension of the standard model. The results summarized include the development of an explicit connection between noncommutative field theory and the standard model extension, placement of new bounds in the photon sector, calculation of one-loop renormalization beta functions in QED, and an analysis of field redefinitions.Comment: 9 pages, to appear in the proceedings for 31st Coral Gables Conference, Ft. Lauderdale, Florid

    Reinforcing the patent system? Effects of patent fences and knowledge diffusion on the development of new industries, technical progress and social welfare

    Get PDF
    This article extends the industry dynamics model of Vallée & Yildizoglu (2006) in order to carry out a richer theoretical analysis of the consequences of a stronger patent system. This model explicitly takes into account the potentially positive effects of patents: publication of patents participates to the building of a collective knowledge stock on which new innovations can rely, and dropped patents can provide a source of technological progress for firms that are lagging behind the leaders of the industry. These dimensions of the patent system are used to question the negative results of Vallée & Yildizoglu (2006). The main results of the new model show that these positive effects do not counterbalance the negative effects of a stronger patent system on social welfare and global technological progress, even if it is a source of better protection and higher profits for the firms. The model also considers the effect of patents on the survival of the newly founded industries and on their development.Innovation, Technical progress, Patent system, Intellectual property rights (IPR), Technology policy
    • 

    corecore