8,528 research outputs found

    Striking a Match in the Historic District: Opposition to Historic Preservation and Responsive Community Building

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    In her 1981 Stanford Law Review article, Carol Rose articulated as a justification for the historic preservation vogue a community building rationale that transformed preservation from an end in itself to a means for community self-definition. Procedurally, Rose argued, preservation laws give communities the power to comment on the direction of development, and impurity of motive does not weaken the cause of community members who use the tools preservation law gives them. Suppose, she suggested, that the primary concern of neighbors is avoiding massive construction, and they emphasize history only as an instrument to oppose change. Such a motive is irrelevant under a rationale that elevates community building and definition over more traditional goals of aestheticism and patriotism. This rationale also would seem to apply in the circumstance where, recognizing the value of rights and preferences they must surrender under proposed historic districting, or choosing instead of preservation another social good, residents oppose restrictive measures imposed on their property at the local level. This essay examines Rose\u27s proposal for the community building possibilities of historic preservation laws, and inquires what role opposition to preservation plays in that model. It looks to the reasons why communities might choose unrestricted demolition and unfettered modification, and offers suggestions for how historic preservation law can better take account of other community goals

    Implicit and Implicit-Explicit Strong Stability Preserving Runge-Kutta Methods with High Linear Order

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    When evolving in time the solution of a hyperbolic partial differential equation, it is often desirable to use high order strong stability preserving (SSP) time discretizations. These time discretizations preserve the monotonicity properties satisfied by the spatial discretization when coupled with the first order forward Euler, under a certain time-step restriction. While the allowable time-step depends on both the spatial and temporal discretizations, the contribution of the temporal discretization can be isolated by taking the ratio of the allowable time-step of the high order method to the forward Euler time-step. This ratio is called the strong stability coefficient. The search for high order strong stability time-stepping methods with high order and large allowable time-step had been an active area of research. It is known that implicit SSP Runge-Kutta methods exist only up to sixth order. However, if we restrict ourselves to solving only linear autonomous problems, the order conditions simplify and we can find implicit SSP Runge-Kutta methods of any linear order. In the current work we aim to find very high linear order implicit SSP Runge-Kutta methods that are optimal in terms of allowable time-step. Next, we formulate an optimization problem for implicit-explicit (IMEX) SSP Runge-Kutta methods and find implicit methods with large linear stability regions that pair with known explicit SSP Runge-Kutta methods of orders plin=3,4,6 as well as optimized IMEX SSP Runge-Kutta pairs that have high linear order and nonlinear orders p=2,3,4. These methods are then tested on sample problems to verify order of convergence and to demonstrate the sharpness of the SSP coefficient and the typical behavior of these methods on test problems

    Argon assisted chemical vapor deposition of CrO2_2: an efficient process leading to high quality epitaxial films

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    A comparative study of the structural, microstructural and magnetic properties of CrO2_2 thin films grown onto (110) and (100) TiO2_2 rutile single crystal substrates by chemical vapor deposition (CVD), using CrO3_3 as chromium precursor and either oxygen or argon as carrier gas is presented. Our results show that growth under argon carrier gas leads to high quality CrO2_2 epilayers with structural and magnetic properties similar to those obtained using the more standard oxygen carrier gas. Furthermore, we interpret the larger magnetic coercivity observed for the (110) oriented films in terms of their microstructure, in particular of the highest strain and edge roughness of the building structures of the CrO2_2 epilayers, which are settled by the substrate crystallographic orientation.Comment: 27 pages, 2 tables, 8 figure

    Correlated Anisotropies in the Cosmic Far-Infrared Background Detected by MIPS/Spitzer: Constraint on the Bias

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    We report the detection of correlated anisotropies in the Cosmic Far-Infrared Background at 160 microns. We measure the power spectrum in the Spitzer/SWIRE Lockman Hole field. It reveals unambiguously a strong excess above cirrus and Poisson contributions, at spatial scales between 5 and 30 arcminutes, interpreted as the signature of infrared galaxy clustering. Using our model of infrared galaxy evolution we derive a linear bias b=1.74 \pm 0.16. It is a factor 2 higher than the bias measured for the local IRAS galaxies. Our model indicates that galaxies dominating the 160 microns correlated anisotropies are at z~1. This implies that infrared galaxies at high redshifts are biased tracers of mass, unlike in the local Universe.Comment: ApJ Letters, in pres
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