12,400 research outputs found

    Our National Parks: Assumptions, Metaphors and Policy Implications

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    Rewriting the Constitution: An Economic Analysis of the Constitutional Amendment Process

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    In this Article, the authors develop an economic theory of the constitutional amendment process under Article V, focusing particularly on the roles that Congress and interest groups play in that process. The authors construct a model to predict when an interest group will seek an amendment rather than a statute to further its interests, highlighting how interest group maintenance costs and anticipated opposition affect that choice. They then discuss the efficiency goals of constitutionalism—precommitment and reduction of agency costs—and argue that the structure of the amendment process under Article V prevents realization of these goals. The authors contrast the Bill of Rights amendments, which established precommitments and reduced the agency costs of government, with the latter seventeen amendments, which expanded the federal government and increased agency costs. They attribute the change in the nature of the amendments to the interest-group domination of the political process and Congress\u27 control over the constitutional amendment agenda. The authors conclude that the Founders\u27 intent to put the Constitution beyond the reach of factions backfired: although factions cannot control the content of the Constitution, neither can the majority. In fact, Article V prevents the majority from precommiting itself and hinders its ability to control the agency costs of government, as evidenced by the history of the failed amendments. Although the authors conclude that Article V thwarts the efficiency goals of constitutionalism, they predict that little can be done to remedy this flaw

    Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone

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    We use interferometric synthetic aperture radar, GPS, and teleseismic data to constrain the relative location of coseismic slip from 11 earthquakes on the subduction interface in northern Chile (23°–25°S) between the years 1993 and 2000. We invert body wave waveforms and geodetic data both jointly and separately for the four largest earthquakes during this time period (1993 M_w 6.8; 1995 M_w 8.1; 1996 M_w 6.7; 1998 M_w 7.1). While the location of slip in the teleseismic-only, geodetic-only, and joint slip inversions is similar for the small earthquakes, there are differences for the 1995 M_w 8.1 event, probably related to nonuniqueness of models that fit the teleseismic data. There is a consistent mislocation of the Harvard centroid moment tensor locations of many of the 6 6 earthquakes, as well as three M_w > 7 events from the 1980s. All of these earthquakes appear to rupture different portions of the fault interface and do not rerupture a limited number of asperities

    Single Atom Imaging with an sCMOS camera

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    Single atom imaging requires discrimination of weak photon count events above background and has typically been performed using either EMCCD cameras, photomultiplier tubes or single photon counting modules. sCMOS provides a cost effective and highly scalable alternative to other single atom imaging technologies, offering fast readout and larger sensor dimensions. We demonstrate single atom resolved imaging of two site-addressable single atom traps separated by 10~μ\mum using an sCMOS camera, offering a competitive signal-to-noise ratio at intermediate count rates to allow high fidelity readout discrimination (error <10−6<10^{-6}) and sub-μ\mum spatial resolution for applications in quantum technologies.Comment: 4 pages, 4 figure

    21-cm signatures of residual HI inside cosmic HII regions during reionization

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    We investigate the impact of sinks of ionizing radiation on the reionization-era 21-cm signal, focusing on 1-point statistics. We consider sinks in both the intergalactic medium and inside galaxies. At a fixed filling factor of HII regions, sinks will have two main effects on the 21-cm morphology: (i) as inhomogeneous absorbers of ionizing photons they result in smaller and more widespread cosmic HII patches; and (ii) as reservoirs of neutral gas they contribute a non-zero 21-cm signal in otherwise ionized regions. Both effects damp the contrast between neutral and ionized patches during reionization, making detection of the epoch of reionization with 21-cm interferometry more challenging. Here we systematically investigate these effects using the latest semi-numerical simulations. We find that sinks dramatically suppress the peak in the redshift evolution of the variance, corresponding to the midpoint of reionization. As previously predicted, skewness changes sign at midpoint, but the fluctuations in the residual HI suppress a late-time rise. Furthermore, large levels of residual HI dramatically alter the evolution of the variance, skewness and power spectrum from that seen at lower levels. In general, the evolution of the large-scale modes provides a better, cleaner, higher signal-to-noise probe of reionization.Comment: Minor edits to agree with MNRAS published versio

    Power measures derived from the sequential query process

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    We study a basic sequential model for the discovery of winning coalitions in a simple game, well known from its use in defining the Shapley-Shubik power index. We derive in a uniform way a family of measures of collective and individual power in simple games, and show that, as for the Shapley-Shubik index, they extend naturally to measures for TU-games. In particular, the individual measures include all weighted semivalues. We single out the simplest measure in our family for more investigation, as it is new to the literature as far as we know. Although it is very different from the Shapley value, it is closely related in several ways, and is the natural analogue of the Shapley value under a nonstandard, but natural, definition of simple game. We illustrate this new measure by calculating its values on some standard examples.Comment: 13 pages, to appear in Mathematical Social Science
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