14,397 research outputs found

    A Study Of Orbital Fractures In A Tertiary Health Care Center

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    A retrospective study of patients with orbital fractures had 48% patients in the age group of 20 – 40 years with male : female ratio of 10:1. Road traffic accidents (71.43%) were the most common cause followed by injury due to fall (20%). Eighty five percent of patients had normal visual acuity at presentation and 65.57% patients had no ocular complaints. Diplopia was present in 14.2% of patients. Of the orbital fractures infraorbital rim was involved in 43.13%, floor in 19.6%, lateral wall in 13.7%, pure blow out in 14.28% and the roof in 2.9%. Important ocular findings were extraocular movements restriction in 9 (10.3%), infraorbital dysaesthesia in 3 (3.4%), enophthalmos in 2, RAPD and globe rupture in 1 patient each. 32 patients underwent surgical management. At the end of 4 months of follow up, 3 had restriction of EOM, 1 patient had vision loss due to globe rupture, 2 had RAPD (optic nerve compression), 1 had lagophthalmos, 1 had exotropia and 1 had atrophic bulbi

    A Derivation Of The Scalar Propagator In A Planar Model In Curved Space

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    Given that the free massive scalar propagator in 2 + 1 dimensional Euclidean space is D(xy)=14πρ0.25cmemρD(x-y)=\frac{1}{4\pi \rho} 0.25cm e^{-m \rho} with ρ2=(xy)2\rho^2=(x-y)^2 we present the counterpart of D(xy)D(x-y) in curved space with a suitably modified version of the Antonsen - Bormann method instead of the familiar Schwinger - de Witt proper time approach, the metric being defined by the rotating solution of Deser et al. of the Einstein field equations associated with a single massless spinning particle located at the origin.Comment: 4pages,Presented at FFP10,Nov.24 - 26,2009,UWA,Perth,To appear in AIP Conference Proceeding

    Reworking the Antonsen-Bormann idea

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    The Antonsen - Bormann idea was originally proposed by these authors for the computation of the heat kernel in curved space; it was also used by the author recently with the same objective but for the Lagrangian density for a real massive scalar field in 2 + 1 dimensional curved space. It is now reworked here with a different purpose - namely, to determine the zeta function for the said model using the Schwinger operator expansion.Comment: To appear in Journal of Physics:Conference Series (2012

    A Size-Free CLT for Poisson Multinomials and its Applications

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    An (n,k)(n,k)-Poisson Multinomial Distribution (PMD) is the distribution of the sum of nn independent random vectors supported on the set Bk={e1,,ek}{\cal B}_k=\{e_1,\ldots,e_k\} of standard basis vectors in Rk\mathbb{R}^k. We show that any (n,k)(n,k)-PMD is poly(kσ){\rm poly}\left({k\over \sigma}\right)-close in total variation distance to the (appropriately discretized) multi-dimensional Gaussian with the same first two moments, removing the dependence on nn from the Central Limit Theorem of Valiant and Valiant. Interestingly, our CLT is obtained by bootstrapping the Valiant-Valiant CLT itself through the structural characterization of PMDs shown in recent work by Daskalakis, Kamath, and Tzamos. In turn, our stronger CLT can be leveraged to obtain an efficient PTAS for approximate Nash equilibria in anonymous games, significantly improving the state of the art, and matching qualitatively the running time dependence on nn and 1/ε1/\varepsilon of the best known algorithm for two-strategy anonymous games. Our new CLT also enables the construction of covers for the set of (n,k)(n,k)-PMDs, which are proper and whose size is shown to be essentially optimal. Our cover construction combines our CLT with the Shapley-Folkman theorem and recent sparsification results for Laplacian matrices by Batson, Spielman, and Srivastava. Our cover size lower bound is based on an algebraic geometric construction. Finally, leveraging the structural properties of the Fourier spectrum of PMDs we show that these distributions can be learned from Ok(1/ε2)O_k(1/\varepsilon^2) samples in polyk(1/ε){\rm poly}_k(1/\varepsilon)-time, removing the quasi-polynomial dependence of the running time on 1/ε1/\varepsilon from the algorithm of Daskalakis, Kamath, and Tzamos.Comment: To appear in STOC 201

    Summary of GaAs Solar Cell Performance and Radiation Damage Workshop

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    The workshop considered the GaAs solar cell capability and promise in several steps: (1) maximum efficiency; (2) space application; (3) major technology problems (AR coating optimization, contacts); (4) radiation resistance; (5) cost and availability; and (6) alternatives. The workshop believes that GaAs solar cells are fast approaching the fulfillment of their potential as candidates for space cells. A maximum efficiency of 20 to 31 percent AMO can be reasonably expected from GaAs based cells, and this may go a little higher with concentration. The use of concentration in space needs to be more carefully evaluated

    GaAs workshop report

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    The advantages of GaAs over silicon are discussed. The substrate problem in solar cell fabrication was reviewed. Future trends in solar energy technology were predicted with special emphasis on cost of production

    Improved Bounds for Universal One-Bit Compressive Sensing

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    Unlike compressive sensing where the measurement outputs are assumed to be real-valued and have infinite precision, in "one-bit compressive sensing", measurements are quantized to one bit, their signs. In this work, we show how to recover the support of sparse high-dimensional vectors in the one-bit compressive sensing framework with an asymptotically near-optimal number of measurements. We also improve the bounds on the number of measurements for approximately recovering vectors from one-bit compressive sensing measurements. Our results are universal, namely the same measurement scheme works simultaneously for all sparse vectors. Our proof of optimality for support recovery is obtained by showing an equivalence between the task of support recovery using 1-bit compressive sensing and a well-studied combinatorial object known as Union Free Families.Comment: 14 page
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