36,653 research outputs found
Remotely sensed and laboratory spectral signatures of an ocean-dumped acid waste
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
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
Weak multiplicativity for random quantum channels
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
Estimations for the Single Diffractive production of the Higgs boson at the Tevatron and the LHC
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 = 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
Bending vibrational data accuracy study
Computer program for predicting structural bending vibrational dat
General moments of the inverse real Wishart distribution and orthogonal Weingarten functions
Let be a random positive definite symmetric matrix distributed according
to a real Wishart distribution and let be its inverse
matrix. We compute general moments 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
We study the stability of the isotropic vacuum Friedmann universe in gravity
theories with higher-order curvature terms of the form
added to the Einstein-Hilbert Lagrangian of general relativity on approach to
an initial cosmological singularity. Earlier, we had shown that, when ,
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 , 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 for both solution branches. On approach to
the initial singularity, the isotropic vacuum solution with scale factor
is found to be stable to tensor perturbations for and stable to vector perturbations for , but is
unstable as otherwise. The solution with scale factor
is not relevant to the case of an initial singularity for
and is unstable as for all for each type of perturbation.Comment: 25 page
Next-to-leading order QCD calculations with parton showers II: soft singularities
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
Despite large uncertainties in the and transverse momentum
() distributions for q_T\lsim 10 GeV, the ratio of the distributions
varys little. The uncertainty in the ratio of to 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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