693 research outputs found

    Necessary and sufficient conditions for path-independence of Girsanov transformation for infinite-dimensional stochastic evolution equations

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    Based on a recent result on linking stochastic differential equations on ℝ d to (finite-dimensional) Burger-KPZ type nonlinear parabolic partial differential equations, we utilize Galerkin type finite-dimensional approximations to characterize the path-independence of the density process of Girsanov transformation for the infinite-dimensional stochastic evolution equations. Our result provides a link of infinite-dimensional semi-linear stochastic differential equations to infinite-dimensional Burgers-KPZ type nonlinear parabolic partial differential equations. As an application, this characterization result is applied to stochastic heat equation in one space dimension over the unit interval

    Rethinking the social impacts of the arts

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    The paper presents a critical discussion of the current debate over the social impacts of the arts in the UK. It argues that the accepted understanding of the terms of the debate is rooted in a number of assumptions and beliefs that are rarely questioned. The paper goes on to present the interim findings of a three‐year research project, which aims to rethink the social impact of the arts, with a view to determining how these impacts might be better understood. The desirability of a historical approach is articulated, and a classification of the claims made within the Western intellectual tradition for what the arts “do” to people is presented and discussed

    Burgers' Flows as Markovian Diffusion Processes

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    We analyze the unforced and deterministically forced Burgers equation in the framework of the (diffusive) interpolating dynamics that solves the so-called Schr\"{o}dinger boundary data problem for the random matter transport. This entails an exploration of the consistency conditions that allow to interpret dispersion of passive contaminants in the Burgers flow as a Markovian diffusion process. In general, the usage of a continuity equation ∂tρ=−∇(v⃗ρ)\partial_t\rho =-\nabla (\vec{v}\rho), where v⃗=v⃗(x⃗,t)\vec{v}=\vec{v}(\vec{x},t) stands for the Burgers field and ρ\rho is the density of transported matter, is at variance with the explicit diffusion scenario. Under these circumstances, we give a complete characterisation of the diffusive transport that is governed by Burgers velocity fields. The result extends both to the approximate description of the transport driven by an incompressible fluid and to motions in an infinitely compressible medium. Also, in conjunction with the Born statistical postulate in quantum theory, it pertains to the probabilistic (diffusive) counterpart of the Schr\"{o}dinger picture quantum dynamics.Comment: Latex fil

    Dynamics of power in contemporary media policy-making

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    Despite the growing interest in the organization and regulation of media industries, there is relatively little public discussion of the material processes through which media policy is developed. At a time of considerable change in the global media environment, new actors and new paradigms are emerging that are set to shift the balance of power between public and private interests in the policy-making process. This article focuses on some core challenges to the pluralist conception of public policy-making that still dominates today and considers whether key aspects of UK and American media policy-making can be said to be competitive, accessible, transparent or rational. Based on interviews with a wide range of ‘stakeholders’, the article assesses the power dynamics that underlie media policy-making and argues that the process is skewed by the taken-for-granted domination of market ideology

    Assessing the Effects of Personal Characteristics and Context on U.S. House Speakers’ Leadership Styles, 1789-2006

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    Research on congressional leadership has been dominated in recent decades by contextual interpretations that see leaders’ behavior as best explained by the environment in which they seek to exercise leadership—particularly, the preference homogeneity and size of their party caucus. The role of agency is thus discounted, and leaders’ personal characteristics and leadership styles are underplayed. Focusing specifically on the speakers of the U.S. House of Representatives from the first to the 110th Congress, we construct measures of each speaker’s commitment to comity and leadership assertiveness. We find the scores reliable and then test the extent to which a speaker’s style is the product of both political context and personal characteristics. Regression estimates on speakers’ personal assertiveness scores provide robust support for a context-plus-personal characteristics explanation, whereas estimates of their comity scores show that speakers’ personal backgrounds trump context
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