67 resultados para paradigm shifts


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We review the effects of dynamical variability on clouds and radiation in observations and models and discuss their implications for cloud feedbacks. Jet shifts produce robust meridional dipoles in upper-level clouds and longwave cloud-radiative effect (CRE), but low-level clouds, which do not simply shift with the jet, dominate the shortwave CRE. Because the effect of jet variability on CRE is relatively small, future poleward jet shifts with global warming are only a second-order contribution to the total CRE changes around the midlatitudes, suggesting a dominant role for thermodynamic effects. This implies that constraining the dynamical response is unlikely to reduce the uncertainty in extratropical cloud feedback. However, we argue that uncertainty in the cloud-radiative response does affect the atmospheric circulation response to global warming, by modulating patterns of diabatic forcing. How cloud feedbacks can affect the dynamical response to global warming is an important topic of future research.

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We study the dynamical properties of certain shift spaces. To help study these properties we introduce two new classes of shifts, namely boundedly supermultiplicative (BSM) shifts and balanced shifts. It turns out that any almost specified shift is both BSM and balanced, and any balanced shift is BSM. However, as we will demonstrate, there are examples of shifts which are BSM but not balanced. We also study the measure theoretic properties of balanced shifts. We show that a shift space admits a Gibbs state if and only if it is balanced. Restricting ourselves to S-gap shifts, we relate certain dynamical properties of an S-gap shift to combinatorial properties from expansions in non-integer bases. This identification allows us to use the machinery from expansions in non-integer bases to give straightforward constructions of S -gap shifts with certain desirable properties. We show that for any q∈(0,1) there is an S-gap shift which has the specification property and entropy q . We also use this identification to address the question, for a given q∈(0,1), how many S-gap shifts exist with entropy q? For certain exceptional values of q there is a unique S-gap shift with this entropy.

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Public–private partnerships (PPPs) are new in Russia and represent project implementation in progress. The government is actively pursuing PPP deployment in sectors such as transportation and urban infrastructure, and at all levels including federal, regional and especially local. Despite the lack of pertinent laws and regulations, the PPP public policy quickly transforms into a policy paradigm that provides simplified concepts and solutions and intensifies partnership development. The article delineates an emerging model of Russia’s PPP policy paradigm, whose structure includes the shared understanding of the need for long-term collaboration between the public sector and business, a changing set of government responsibilities that imply an increasing private provision of public services, and new institutional capacities. This article critically appraises the principal dynamics that contribute to an emerging PPP policy paradigm, namely the broad government treatment of the meaning of a partnership and of a contractual PPP; a liberal PPP approval process that lacks clear guidelines and consistency across regions; excessive emphasis on positive PPP externalities and neglect of drawbacks; and unjustifiably extensive government financial support to PPPs. Whilst a paradigm appears to be useful specifically for the policy purpose of PPP expansion, it may also mask inefficiencies such as higher prices of public services and greater government risks.

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This article explores the way users of an online gay chat room negotiate the exchange of photographs and the conduct of video conferencing sessions and how this negotiation changes the way participants manage their interactions and claim and impute social identities. Different modes of communication provide users with different resources for the control of information, affecting not just what users are able to reveal, but also what they are able to conceal. Thus, the shift from a purely textual mode for interacting to one involving visual images fundamentally changes the kinds of identities and relationships available to users. At the same time, the strategies users employ to negotiate these shifts of mode can alter the resources available in different modes. The kinds of social actions made possible through different modes, it is argued, are not just a matter of the modes themselves but also of how modes are introduced into the ongoing flow of interaction.