2,988 research outputs found

    Scattering low-frequency sound in the ocean

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    Kepler-210: An active star with at least two planets

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    We report the detection and characterization of two short-period, Neptune-sized planets around the active host star Kepler-210. The host star's parameters derived from those planets are (a) mutually inconsistent and (b) do not conform to the expected host star parameters. We furthermore report the detection of transit timing variations (TTVs) in the O-C diagrams for both planets. We explore various scenarios that explain and resolve those discrepancies. A simple scenario consistent with all data appears to be one that attributes substantial eccentricities to the inner short-period planets and that interprets the TTVs as due to the action of another, somewhat longer period planet. To substantiate our suggestions, we present the results of N-body simulations that modeled the TTVs and that checked the stability of the Kepler-210 system.Comment: 8 pages, 8 Encapsulated Postscript figure

    Long Range Magnetic Order and the Darwin Lagrangian

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    We simulate a finite system of NN confined electrons with inclusion of the Darwin magnetic interaction in two- and three-dimensions. The lowest energy states are located using the steepest descent quenching adapted for velocity dependent potentials. Below a critical density the ground state is a static Wigner lattice. For supercritical density the ground state has a non-zero kinetic energy. The critical density decreases with NN for exponential confinement but not for harmonic confinement. The lowest energy state also depends on the confinement and dimension: an antiferromagnetic cluster forms for harmonic confinement in two dimensions.Comment: 5 figure

    Werkmethoden bij het oogsten van riet

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    Unipotent group actions on affine varieties

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    Algebraic actions of unipotent groups UU actions on affine k−k-varieties XX (kk an algebraically closed field of characteristic 0) for which the algebraic quotient X//UX//U has small dimension are considered.. In case XX is factorial, O(X)∗=k∗,O(X)^{\ast}=k^{\ast}, and X//UX//U is one-dimensional, it is shown that O(X)UO(X)^{U}=k[f]k[f], and if some point in XX has trivial isotropy, then XX is UU equivariantly isomorphic to U×A1(k).U\times A^{1}(k). The main results are given distinct geometric and algebraic proofs. Links to the Abhyankar-Sathaye conjecture and a new equivalent formulation of the Sathaye conjecture are made.Comment: 10 pages. This submission comes out of an older submission ("A commuting derivations theorem on UFDs") and contains part of i

    Designing for multi-user interaction in the home environment: Implementing social translucence

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    © 2016 ACM. Interfaces of interactive systems for domestic use are usually designed for individual interactions although these interactions influence multiple users. In order to prevent conflicts and unforeseen influences on others we propose to leverage the human ability to take each other into consideration in the interaction. A promising approach for this is found in the social translucence framework, which was originally described by Erickson & Kellogg. In this paper, we investigate how to design multi-user interfaces for domestic interactive systems through two design cases where we focus on the implementation of social translucence constructs (visibility, awareness, and accountability) in the interaction. We use the resulting designs to extract design considerations: interfaces should not prescribe behavior, need to offer sufficient interaction alternatives, and previous settings need to be retrievable. We also identify four steps that can be integrated in any design process to help designers in creating interfaces that support multi-user interaction through social translucence

    Generating Diffusion MRI scalar maps from T1 weighted images using generative adversarial networks

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    Diffusion magnetic resonance imaging (diffusion MRI) is a non-invasive microstructure assessment technique. Scalar measures, such as FA (fractional anisotropy) and MD (mean diffusivity), quantifying micro-structural tissue properties can be obtained using diffusion models and data processing pipelines. However, it is costly and time consuming to collect high quality diffusion data. Here, we therefore demonstrate how Generative Adversarial Networks (GANs) can be used to generate synthetic diffusion scalar measures from structural T1-weighted images in a single optimized step. Specifically, we train the popular CycleGAN model to learn to map a T1 image to FA or MD, and vice versa. As an application, we show that synthetic FA images can be used as a target for non-linear registration, to correct for geometric distortions common in diffusion MRI

    DI-MMAP: A High Performance Memory-Map Runtime for Data-Intensive Applications

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    Abstract not provide

    Processing of MEMPHIS millimeter wave multi-baseline InSAR data

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    This paper presents a processing method for multi-baseline interferometric data acquired with the MEMPHIS airborne sensor. The processing method ingests the SAR raw data from each receiver and extends up to the generation of digital elevation models (DEMs). Critical steps include the correction of the azimuth phase undulations, the multi- baseline processing and the phase-to-DEM conversion. Methods for resolving the various hurdles were adapted to the MEMPHIS sensor and are presented here. The results obtained for a data take over a test site near Zurich, Switzerland are shown; these results are in a good agreement with comparable LIDAR products
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