22,779 research outputs found

    Application of remote sensing technology to land evaluation, planning utilization of land resources, and assessment of westland habitat in eastern South Dakota, parts 1 and 2

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    The author has identified the following significant results. LANDSAT fulfilled the requirements for general soils and land use information. RB-57 imagery was required to provide the information and detail needed for mapping soils for land evaluation. Soils maps for land evaluation were provided on clear mylar at the scale of the county highway map to aid users in locating mapping units. Resulting mapped data were computer processed to provided a series of interpretive maps (land value, limitations to development, etc.) and area summaries for the users

    Consistency of the Shannon entropy in quantum experiments

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    The consistency of the Shannon entropy, when applied to outcomes of quantum experiments, is analysed. It is shown that the Shannon entropy is fully consistent and its properties are never violated in quantum settings, but attention must be paid to logical and experimental contexts. This last remark is shown to apply regardless of the quantum or classical nature of the experiments.Comment: 12 pages, LaTeX2e/REVTeX4. V5: slightly different than the published versio

    Reconstruction of tomographic images of dry aqueous foams

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    WOS:000328011500007International audienceX-ray tomography offers the possibility to examine the local changes in the structure of a three-dimensional aqueous foam as it flows, allowing a better fundamental understanding of foam rheology and the validation of models. We present an automated algorithm that reconstructs a dry aqueous foam from such images. Our algorithm uses ImageJ to extract from an image the topology of the network of Plateau borders in the foam, and then analyses this network to re-create the films and then the bubbles, and equilibrates the structure in Surface Evolver. We validate our algorithm and demonstrate its precision by applying it to simulated foam structures and analysing the topology and geometry obtained. We then apply our algorithm to a sequence of images from an experiment in which a spherical bead falls under its own weight through a polydisperse dry foam. This allows us to describe the evolution of the foam's bubble volumes with time as well as the distribution of bubble pressure and the forces exerted on a falling sphere. (C) 2013 Elsevier B.V. All rights reserved

    Model-based aberration corrected microscopy inside a glass tube

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    Microscope objectives achieve near diffraction-limited performance only when used under the conditions they are designed for. In non-standard geometries, such as thick cover slips or curved surfaces, severe aberrations arise, inevitably impairing high-resolution imaging. Correcting such large aberrations using standard adaptive optics can be challenging: existing solutions are either not suited for strong aberrations, or require extensive feedback measurements, consequently taking a significant portion of the photon budget. We demonstrate that it is possible to pre-compute the corrections needed for high-resolution imaging inside a glass tube based on a priori information only. Our ray-tracing based method achieved over an order of magnitude increase in image contrast without the need for a feedback signal.Comment: 9 pages, 3 figures, 1 table. Submitted to Optics Expres

    Self-similar stable processes arising from high-density limits of occupation times of particle systems

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    We extend results on time-rescaled occupation time fluctuation limits of the (d,α,β)(d,\alpha, \beta)-branching particle system (0<α2,0<β1)(0<\alpha \leq 2, 0<\beta \leq 1) with Poisson initial condition. The earlier results in the homogeneous case (i.e., with Lebesgue initial intensity measure) were obtained for dimensions d>α/βd>\alpha / \beta only, since the particle system becomes locally extinct if dα/βd\le \alpha / \beta. In this paper we show that by introducing high density of the initial Poisson configuration, limits are obtained for all dimensions, and they coincide with the previous ones if d>α/βd>\alpha/\beta. We also give high-density limits for the systems with finite intensity measures (without high density no limits exist in this case due to extinction); the results are different and harder to obtain due to the non-invariance of the measure for the particle motion. In both cases, i.e., Lebesgue and finite intensity measures, for low dimensions (d<α(1+β)/βd<\alpha(1+\beta)/\beta and d<α(2+β)/(1+β)d<\alpha(2+\beta)/(1+\beta), respectively) the limits are determined by non-L\'evy self-similar stable processes. For the corresponding high dimensions the limits are qualitatively different: S(Rd){\cal S}'(R^d)-valued L\'evy processes in the Lebesgue case, stable processes constant in time on (0,)(0,\infty) in the finite measure case. For high dimensions, the laws of all limit processes are expressed in terms of Riesz potentials. If β=1\beta=1, the limits are Gaussian. Limits are also given for particle systems without branching, which yields in particular weighted fractional Brownian motions in low dimensions. The results are obtained in the setup of weak convergence of S'(R^d)$-valued processes.Comment: 28 page

    Kondo Effects and Multipolar Order in the cubic PrTr2Al20 (Tr=Ti, V)

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    Our single crystal study reveals that PrTr2Al20 (Tr = Ti and V) provides the first examples of a cubic {\Gamma}3 nonmagnetic ground doublet system that shows the Kondo effect including a -ln T dependent resistivity. The {\Gamma}3 quadrupolar moments in PrV2Al20 induce anomalous metallic behavior through hybridization with conduction electrons, such as T^{1/2} dependent resistivity and susceptibility below ~ 20 K down to its ordering temperature T_O = 0.6 K. In PrTi2Al20, however, quadrupoles are well-localized and exhibit an order at T_O = 2.0 K. Stronger Kondo coupling in PrV2Al20 than in PrTi2Al20 suppresses quadrupolar ordering, and instead promotes hybridization between the {\Gamma}3 doublet and conduction electrons, leading to most likely the quadrupolar Kondo effect.Comment: 12 pages, 4 figure

    3D Simulations of MHD Jet Propagation Through Uniform and Stratified External Environments

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    We present a set of high-resolution 3D MHD simulations of steady light, supersonic jets, exploring the influence of jet Mach number and the ambient medium on jet propagation and energy deposition over long distances. The results are compared to simple self-similar scaling relations for the morphological evolution of jet-driven structures and to previously published 2D simulations. For this study we simulated the propagation of light jets with internal Mach numbers 3 and 12 to lengths exceeding 100 initial jet radii in both uniform and stratified atmospheres. The propagating jets asymptotically deposit approximately half of their energy flux as thermal energy in the ambient atmosphere, almost independent of jet Mach number or the external density gradient. Nearly one-quarter of the jet total energy flux goes directly into dissipative heating of the ICM, supporting arguments for effective feedback from AGNs to cluster media. The remaining energy resides primarily in the jet and cocoon structures. Despite having different shock distributions and magnetic field features, global trends in energy flow are similar among the different models. As expected the jets advance more rapidly through stratified atmospheres than uniform environments. The asymptotic head velocity in King-type atmospheres shows little or no deceleration. This contrasts with jets in uniform media with heads that are slowed as they propagate. This suggests that the energy deposited by jets of a given length and power depends strongly on the structure of the ambient medium. While our low-Mach jets are more easily disrupted, their cocoons obey evolutionary scaling relations similar to the high-Mach jets.Comment: Accepted in ApJ, 32 pages, 18 figures, animations available from: http://www.msi.umn.edu/Projects/twj/newsite/projects/radiojets/movies

    Scaling analysis of the magnetic monopole mass and condensate in the pure U(1) lattice gauge theory

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    We observe the power law scaling behavior of the monopole mass and condensate in the pure compact U(1) gauge theory with the Villain action. In the Coulomb phase the monopole mass scales with the exponent \nu_m=0.49(4). In the confinement phase the behavior of the monopole condensate is described with remarkable accuracy by the exponent \beta_{exp}=0.197(3). Possible implications of these phenomena for a construction of a strongly coupled continuum U(1) gauge theory are discussed.Comment: Added references [1

    Transition from overscreening to underscreening in the multichannel Kondo model: exact solution at large N

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    A novel large-N limit of the multichannel Kondo model is introduced, for representations of the impurity spin described by Schwinger bosons. Three cases are found, associated with underscreening, overscreening and exact Kondo screening of the impurity. The saddle-point equations derived in this limit are reminiscent of the ``non-crossing approximation'', but preserve the Fermi-liquid nature of the model in the exactly screened case. Several physical quantities are computed, both numerically, and analytically in the low-\omega,T limit, and compared to other approaches.Comment: 4 pages, RevTeX3.0, 2 EPS figures. Published versio
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