3,203 research outputs found

    Compilation, design tests: Energetic particles Satellite S-3 including design tests for S-3A, S-3B and S-3C

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    A compilation of engineering design tests which were conducted in support of the Energetic Particle Satellite S-3, S-3A, and S-3b programs. The purpose for conducting the tests was to determine the adequacy and reliability of the Energetic Particles Series of satellites designs. The various tests consisted of: (1) moments of inertia, (2) functional reliability, (3) component and structural integrity, (4) initiators and explosives tests, and (5) acceptance tests

    Small violations of full correlation Bell inequalities for multipartite pure random states

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    We estimate the probability of random NN-qudit pure states violating full-correlation Bell inequalities with two dichotomic observables per site. These inequalities can show violations that grow exponentially with NN, but we prove this is not the typical case. For many-qubit states the probability to violate any of these inequalities by an amount that grows linearly with NN is vanishingly small. If each system's Hilbert space dimension is larger than two, on the other hand, the probability of seeing \emph{any} violation is already small. For the qubits case we discuss furthermore the consequences of this result for the probability of seeing arbitrary violations (\emph i.e., of any order of magnitude) when experimental imperfections are considered.Comment: 16 pages, one colum

    Standing in the Shadows of Obesity: The Local Food Environment and Obesity in Detroit

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    Much of the literature examining associations between local food environments and obesity fail to consider whether or not respondents actually utilise the food stores around them. Drawing on survey data, this study examines the relationships between the neighbourhood food environment, mobility and obesity among residents from the lower eastside neighbourhoods of Detroit, Michigan. Certain dimensions of the local food environment are found to contribute to obesity, but these dimensions occur at different scales. Residents who rely on their immediate neighbourhood food environment have a higher likelihood of being obese than residents who do not utilise the stores around them. At a broader level, lower eastside Detroit residents with a greater concentration of fast food establishments around them have a higher possibility of being obese than residents with fewer fast food restaurants around them. The salience of the fast food environment warrants additional attention in terms of public health interventions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139092/1/tesg12227.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139092/2/tesg12227_am.pd

    Sparsity and Incoherence in Compressive Sampling

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    We consider the problem of reconstructing a sparse signal x0Rnx^0\in\R^n from a limited number of linear measurements. Given mm randomly selected samples of Ux0U x^0, where UU is an orthonormal matrix, we show that 1\ell_1 minimization recovers x0x^0 exactly when the number of measurements exceeds mConstμ2(U)Slogn, m\geq \mathrm{Const}\cdot\mu^2(U)\cdot S\cdot\log n, where SS is the number of nonzero components in x0x^0, and μ\mu is the largest entry in UU properly normalized: μ(U)=nmaxk,jUk,j\mu(U) = \sqrt{n} \cdot \max_{k,j} |U_{k,j}|. The smaller μ\mu, the fewer samples needed. The result holds for ``most'' sparse signals x0x^0 supported on a fixed (but arbitrary) set TT. Given TT, if the sign of x0x^0 for each nonzero entry on TT and the observed values of Ux0Ux^0 are drawn at random, the signal is recovered with overwhelming probability. Moreover, there is a sense in which this is nearly optimal since any method succeeding with the same probability would require just about this many samples

    Serendipitous discovery of a projected pair of QSOs separated by 4.5 arcsec on the sky

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    We present the serendipitous discovery of a projected pair of quasi-stellar objects (QSOs) with an angular separation of Δθ=4.50\Delta\theta =4.50 arcsec. The redshifts of the two QSOs are widely different: one, our programme target, is a QSO with a spectrum consistent with being a narrow line Seyfert 1 AGN at z=2.05z=2.05. For this target we detect Lyman-α\alpha, \ion{C}{4}, and \ion{C}{3]}. The other QSO, which by chance was included on the spectroscopic slit, is a Type 1 QSO at a redshift of z=1.68z=1.68, for which we detect \ion{C}{4}, \ion{C}{3]} and \ion{Mg}{2}. We compare this system to previously detected projected QSO pairs and find that only about a dozen previously known pairs have smaller angular separation.Comment: 4 pages, 3 figures. Accepted for publication in A

    KECK HIRES Spectroscopy of APM 08279+5255

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    With an optical R-band magnitude of 15.2, the recently discovered z=3.911 BAL quasar APM 08279+5255 is an exceptionally bright high redshift source. Its brightness has allowed us to acquire a high signal-to-noise ratio (~100), high resolution (~6 km/s) spectrum using the HIRES echelle spectrograph on the 10-m Keck I telescope. Given the quality of the data, these observations provide an unprecedented view of associated and intervening absorption systems. Here we announce the availability of this spectrum to the general astronomical community and present a brief analysis of some of its main features.Comment: 21 pages including 5 figures. Accepted for publication by PAS

    Perimeter of sublevel sets in infinite dimensional spaces

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    We compare the perimeter measure with the Airault-Malliavin surface measure and we prove that all open convex subsets of abstract Wiener spaces have finite perimeter. By an explicit counter-example, we show that in general this is not true for compact convex domains
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