35,999 research outputs found

    Remotely sensed and laboratory spectral signatures of an ocean-dumped acid waste

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    An ocean-dumped acid waste plume was studied by using a rapid scanning spectrometer to remotely measure ocean radiance from a helicopter. The results of these studies are presented and compared with results from sea truth samples and laboratory experiments. An ocean spectral reflectance signature and a laboratory spectral transmission signature were established for the iron-acid waste pollutant. The spectrally and chemically significant component of the acid waste pollutant was determined to be ferric iron

    Spacecraft Dynamics as Related to Laboratory Experiments in Space

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    Proceedings are presented of a conference sponsored by the Physics and Chemistry Experiments in Space Working Group to discuss the scientific and engineering aspects involved in the design and performance of reduced to zero gravity experiments affected by spacecraft environments and dynamics. The dynamics of drops, geophysical fluids, and superfluid helium are considered as well as two phase flow, combustion, and heat transfer. Interactions between spacecraft motions and the atmospheric cloud physics laboratory experiments are also examined

    Estimations for the Single Diffractive production of the Higgs boson at the Tevatron and the LHC

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    The single diffractive production of the standard model Higgs boson is computed using the diffractive factorization formalism, taking into account a parametrization for the Pomeron structure function provided by the H1 Collaboration. We compute the cross sections at next-to-leading order accuracy for the gluon fusion process, which includes QCD and electroweak corrections. The gap survival probability () is also introduced to account for the rescattering corrections due to spectator particles present in the interaction, and to this end we compare two different models for the survival factor. The diffractive ratios are predicted for proton-proton collisions at the Tevatron and the LHC for the Higgs boson mass of MHM_H = 120 GeV. Therefore, our results provide updated estimations for the diffractive ratios of the single diffractive production of the Higgs boson in the Tevatron and LHC kinematical regimes.Comment: 20 pages, 6 figures, 3 table

    Weak multiplicativity for random quantum channels

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    It is known that random quantum channels exhibit significant violations of multiplicativity of maximum output p-norms for any p>1. In this work, we show that a weaker variant of multiplicativity nevertheless holds for these channels. For any constant p>1, given a random quantum channel N (i.e. a channel whose Stinespring representation corresponds to a random subspace S), we show that with high probability the maximum output p-norm of n copies of N decays exponentially with n. The proof is based on relaxing the maximum output infinity-norm of N to the operator norm of the partial transpose of the projector onto S, then calculating upper bounds on this quantity using ideas from random matrix theory.Comment: 21 pages; v2: corrections and additional remark

    Bending vibrational data accuracy study

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    Computer program for predicting structural bending vibrational dat

    General moments of the inverse real Wishart distribution and orthogonal Weingarten functions

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    Let WW be a random positive definite symmetric matrix distributed according to a real Wishart distribution and let W1=(Wij)i,jW^{-1}=(W^{ij})_{i,j} be its inverse matrix. We compute general moments E[Wk1k2Wk3k4...Wk2n1k2n]\mathbb{E} [W^{k_1 k_2} W^{k_3 k_4} ... W^{k_{2n-1}k_{2n}}] explicitly. To do so, we employ the orthogonal Weingarten function, which was recently introduced in the study for Haar-distributed orthogonal matrices. As applications, we give formulas for moments of traces of a Wishart matrix and its inverse.Comment: 29 pages. The last version differs from the published version, but it includes Appendi

    The Stability of an Isotropic Cosmological Singularity in Higher-Order Gravity

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    We study the stability of the isotropic vacuum Friedmann universe in gravity theories with higher-order curvature terms of the form (RabRab)n(R_{ab}R^{ab})^{n} added to the Einstein-Hilbert Lagrangian of general relativity on approach to an initial cosmological singularity. Earlier, we had shown that, when % n=1, a special isotropic vacuum solution exists which behaves like the radiation-dominated Friedmann universe and is stable to anisotropic and small inhomogeneous perturbations of scalar, vector and tensor type. This is completely different to the situation that holds in general relativity, where an isotropic initial cosmological singularity is unstable in vacuum and under a wide range of non-vacuum conditions. We show that when n1n\neq 1, although a special isotropic vacuum solution found by Clifton and Barrow always exists, it is no longer stable when the initial singularity is approached. We find the particular stability conditions under the influence of tensor, vector, and scalar perturbations for general nn for both solution branches. On approach to the initial singularity, the isotropic vacuum solution with scale factor a(t)=tP/3a(t)=t^{P_{-}/3} is found to be stable to tensor perturbations for 0.5<n<1.13090.5<n< 1.1309 and stable to vector perturbations for 0.861425<n10.861425 < n \leq 1, but is unstable as t0t \to 0 otherwise. The solution with scale factor a(t)=tP+/3a(t)=t^{P_{+}/3} is not relevant to the case of an initial singularity for n>1n>1 and is unstable as t0t \to 0 for all nn for each type of perturbation.Comment: 25 page

    Next-to-leading order QCD calculations with parton showers II: soft singularities

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    Programs that calculate observables in quantum chromodynamics at next-to-leading order typically generate events that consist of partons rather than hadrons -- and just a few partons at that. These programs would be much more useful if the few partons were turned into parton showers, which could be given to one of the Monte Carlo event generators to produce hadron showers. In a previous paper, we have seen how to generate parton showers related to the final state collinear singularities of the perturbative calculation for the example of e+ + e- --> 3 jets. This paper discusses the treatment of the soft singularities.Comment: 26 pages with 5 figures. This version is close to the version to be publishe

    Relative distributions of W's and Z's at low transverse momenta

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    Despite large uncertainties in the W±W^\pm and Z0Z^0 transverse momentum (qTq_T) distributions for q_T\lsim 10 GeV, the ratio of the distributions varys little. The uncertainty in the ratio of WW to ZZ qTq_T distributions is on the order of a few percent, independent of the details of the nonperturbative parameterization.Comment: 13 pages in revtex, 5 postscript figures available upon request, UIOWA-94-0
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