2,421 research outputs found

    Art Practice and the Community

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    ART AS SOCIAL ACTION will be a general introduction and textbook to the field of social practice art and include valuable lesson plans offering examples of pedagogical projects for instructors at both the college and high school levels. With contributions written by leading social practice artists, teachers and thinkers it's content will be arranged thematically to around such themes as labor rights, environmental justice, urban policy, the rights of women and girls, inequality, migrant's rights, Black Lives Matter, the rights of prisoner's and the global nexus of art/labor/capital among other areas of topical concern. Some lesson plans will be written by the students, alumni and faculty members of Social Practice Queens (SPQ), a unique partnership between Queens College CUNY and the Queens Museum. The book will consist of two main parts. A set of introductory materials focused on the concept of teaching socially engaged art (with some of these essays having an associated 20 minute podcast created for classroom use online at: http://www.socialpracticequeens.org/ ). Part two of the book will consist of two dozen actual lesson plans

    Cluster-based ensemble means for climate model intercomparison

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    Clustering – the automated grouping of similar data – can provide powerful and unique insight into large and complex data sets, in a fast and computationally efficient manner. While clustering has been used in a variety of fields (from medical image processing to economics), its application within atmospheric science has been fairly limited to date, and the potential benefits of the application of advanced clustering techniques to climate data (both model output and observations) has yet to be fully realised. In this paper, we explore the specific application of clustering to a multi-model climate ensemble. We hypothesise that clustering techniques can provide (a) a flexible, data-driven method of testing model–observation agreement and (b) a mechanism with which to identify model development priorities. We focus our analysis on chemistry–climate model (CCM) output of tropospheric ozone – an important greenhouse gas – from the recent Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). Tropospheric column ozone from the ACCMIP ensemble was clustered using the Data Density based Clustering (DDC) algorithm. We find that a multi-model mean (MMM) calculated using members of the most-populous cluster identified at each location offers a reduction of up to  ∼  20 % in the global absolute mean bias between the MMM and an observed satellite-based tropospheric ozone climatology, with respect to a simple, all-model MMM. On a spatial basis, the bias is reduced at  ∼  62 % of all locations, with the largest bias reductions occurring in the Northern Hemisphere – where ozone concentrations are relatively large. However, the bias is unchanged at 9 % of all locations and increases at 29 %, particularly in the Southern Hemisphere. The latter demonstrates that although cluster-based subsampling acts to remove outlier model data, such data may in fact be closer to observed values in some locations. We further demonstrate that clustering can provide a viable and useful framework in which to assess and visualise model spread, offering insight into geographical areas of agreement among models and a measure of diversity across an ensemble. Finally, we discuss caveats of the clustering techniques and note that while we have focused on tropospheric ozone, the principles underlying the cluster-based MMMs are applicable to other prognostic variables from climate models

    The Taylor rule and the practice of central banking

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    The Taylor rule has revolutionized the way many policymakers at central banks think about monetary policy. It has framed policy actions as a systematic response to incoming information about economic conditions, as opposed to a period-by-period optimization problem. It has emphasized the importance of adjusting policy rates more than one-for-one in response to an increase in inflation. And, various versions of the Taylor rule have been incorporated into macroeconomic models that are used at central banks to understand and forecast the economy. ; This paper examines how the Taylor rule is used as an input in monetary policy deliberations and decision-making at central banks. The paper characterizes the policy environment at the time of the development of the Taylor rule and describes how and why the Taylor rule became integrated into policy discussions and, in some cases, the policy framework itself. Speeches by policymakers and transcripts and minutes of policy meetings are examined to explore the practical uses of the Taylor rule by central bankers. While many issues remain unresolved and views still differ about how the Taylor rule can best be applied in practice, the paper shows that the rule has advanced the practice of central banking.

    The Energy Landscape of Myoglobin: An Optical Study

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    In this paper we demonstrate how the potential energy surface of a protein, which determines its conformational degrees of freedom, can be constructed from a series of advanced nonlinear optical experiments. The energy landscape of myoglobin was probed by studying its low-temperature structural dynamics, using several spectral hole burning and photon echo techniques. The spectral diffusion of the heme group of the protein was studied on a time scale ranging from nanoseconds to several days while covering a temperature range from 100 mK to 23 K. The spectral line broadening, as measured in three-pulse stimulated photon echo experiments, occurs in a stepwise fashion, while the exact time dependence of the line width is critically dependent on temperature. From these results we obtained the energy barriers between the conformational states of the protein. Aging time dependent hole-burning experiments show that, at 100 mK, it takes several days for the protein to reach thermal equilibrium. When, after this period a spectral hole is burned, the line broadening induced by well-defined temperature cycles is partly reversed over a period of several hours. From this we conclude that a rough structure is superimposed on the overall shape of the potential energy surface of the protein. By combining the hole burning and photon echo results, we construct a detailed image of this energy landscape, supporting the general concept of a structural hierarchy. More specifically, we show that the number of conformational substates in the lower hierarchical tiers is much lower than was previously anticipated and, in fact, is comparable to the number of taxonomic substates.

    The Taylor rule and the transformation of monetary policy

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    This paper examines the intellectual history of the Taylor Rule and its considerable influence on macroeconomic research and monetary policy. The paper traces the historical antecedents to the Taylor rule, emphasizing the contributions of three prominent advocates of rules--Henry Simons, A.W. H. Phillips, and Milton Friedman. The paper then examines the evolution of John Taylor's thinking as an academic and policy advisor leading up to his formulation of the Taylor rule. Finally, the paper documents the influence of the Taylor rule on macroeconomic research and the Federal Reserve's conduct of monetary policy.Taylor's rule ; Taylor, John B. ; Simons, Henry ; Phillips, A.W.H. ; Friedman, Milton ; Monetary policy

    p-Adic Models of Ultrametric Diffusion Constrained by Hierarchical Energy Landscapes

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    We demonstrate that p-adic analysis is a natural basis for the construction of a wide variety of the ultrametric diffusion models constrained by hierarchical energy landscapes. A general analytical description in terms of p-adic analysis is given for a class of models. Two exactly solvable examples, i.e. the ultrametric diffusion constraned by the linear energy landscape and the ultrametric diffusion with reaction sink, are considered. We show that such models can be applied to both the relaxation in complex systems and the rate processes coupled to rearrangenment of the complex surrounding.Comment: 14 pages, 6 eps figures, LaTeX 2.0

    A revised look at the effects of the Channel Model on molecular communication system

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    Molecular communications, where information is passed between the Transmitter (TX) and the Receiver (RX) via molecules is a promising area with vast potential applications. However, the infancy of the topic within the overall taxonomy of communications has meant that to date, several channel models are in press, each of which is applied under various constraints and/or assumptions. Amongst them is that the arrival of molecules in different time slots can be, or is, considered as independent events. In practice, this assumption is not accurate, as the molecules arriving in the previous slot reduce the possible number of molecules in the next slot and hence make them correlated. In this letter, we analyze a more realistic performance of a molecular communication assuming correlated events. The key result shown, is that the widely used model assuming independent events significantly overestimates the error rates in the channel. This result is thus critical to researchers who focus on energy use at the nano-scale, as the new analysis provides a more realistic prediction and therefore, less energy will be needed to attain a desired error rate, increasing system feasibility

    Validity of Ligand Efficiency Metrics

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    A recent viewpoint article (Improving the plausibility of success with inefficient metrics. ACS Med. Chem. Lett. 2014, 5, 2-5) argued that the standard definition of ligand efficiency (LE) is mathematically invalid. In this viewpoint, we address this criticism and show categorically that the definition of LE is mathematically valid. LE and other metrics such as lipophilic ligand efficiency (LLE) can be useful during the multiparameter optimization challenge faced by medicinal chemists

    Stability of Resonant Opto-Mechanical Oscillators

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    We theoretically study the frequency stability of an opto-mechanical radio frequency oscillator based on resonant interaction of two optical and one mechanical modes of the same optical microcavity. A generalized expression for the phase noise of the oscillator is derived using Langevin formalism and compared to the phase noise of existing electronic oscillators.Comment: 6 pages, 1 figur

    From Anti-equilibrium to The Socialist System and Beyond

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    This essay attempts to understand János Kornai’s works from a political economy perspective. It argues that Kornai has significantly contributed to the formation of a new paradigm of political economy. The main endeavor of Kornai has been the combination of analytical concepts of economics with the empirical description of real economies. After a certain period of theoretical experimentation János Kornai formulated his research program that can be called the shortage economy explanation of the socialist system. The Economics of Shortage and The Socialist System have created a new theoretical paradigm in a framework in which it has become possible to establish a connection between the analytical and empirical, universal and historical aspects of the theory studying the socialist system as a real economic entity. János Kornai has built his analysis of the socialist system on the primary role of politics in the creation of economic institutions. In his present work on capitalism he has extended this thesis to the capitalist system. This seems to be an important contribution of his to a new political economy paradigm that is just in the process of formation
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