35,832 research outputs found
Impact of edge-removal on the centrality betweenness of the best spreaders
The control of epidemic spreading is essential to avoid potential fatal
consequences and also, to lessen unforeseen socio-economic impact. The need for
effective control is exemplified during the severe acute respiratory syndrome
(SARS) in 2003, which has inflicted near to a thousand deaths as well as
bankruptcies of airlines and related businesses. In this article, we examine
the efficacy of control strategies on the propagation of infectious diseases
based on removing connections within real world airline network with the
associated economic and social costs taken into account through defining
appropriate quantitative measures. We uncover the surprising results that
removing less busy connections can be far more effective in hindering the
spread of the disease than removing the more popular connections. Since
disconnecting the less popular routes tend to incur less socio-economic cost,
our finding suggests the possibility of trading minimal reduction in
connectivity of an important hub with efficiencies in epidemic control. In
particular, we demonstrate the performance of various local epidemic control
strategies, and show how our approach can predict their cost effectiveness
through the spreading control characteristics.Comment: 11 pages, 4 figure
New Production Mechanism of Neutral Higgs Bosons with Right scalar tau neutrino as the LSP
Motived by the neutrino oscillation data, we consider the lightest tau
sneutrino (which is mostly the right tau sneutrino) to be
the lightest supersymmetric particle (LSP) in the framework of the minimal
supersymmetric Standard Model. Both the standard and the non-standard trilinear
scalar coupling terms are included for the right tau sneutrino interactions.
The decay branching ratio of
can become so large that the production rate of the lightest neutral Higgs
boson () can be largely enhanced at electron or hadron colliders, either
from the direct production of or from the decay of
charginos, neutralinos, sleptons, and the cascade decay of squarks and gluinos,
etc. Furthermore, because of the small LSP annihilation rate, can be a good candidate for cold dark matter.Comment: 11 pages, RevTex, 3 eps figures. We clarify the theoretical framework
of this study, with a note added in the end, and correct an equation, with
updated figure
Multivariate Fitting and the Error Matrix in Global Analysis of Data
When a large body of data from diverse experiments is analyzed using a
theoretical model with many parameters, the standard error matrix method and
the general tools for evaluating errors may become inadequate. We present an
iterative method that significantly improves the reliability of the error
matrix calculation. To obtain even better estimates of the uncertainties on
predictions of physical observables, we also present a Lagrange multiplier
method that explores the entire parameter space and avoids the linear
approximations assumed in conventional error propagation calculations. These
methods are illustrated by an example from the global analysis of parton
distribution functions.Comment: 13 pages, 5 figures, Latex; minor clarifications, fortran program
made available; Normalization of Hessian matrix changed to HEP standar
Experimental demonstration of an efficient quantum phase-covariant cloning and its possible applications to simulating eavesdropping in quantum cryptography
We describe a nuclear magnetic resonance (NMR) experiment which implements an
efficient one-to-two qubit phase-covariant cloning machine(QPCCM). In the
experiment we have achieved remarkably high fidelities of cloning, 0.848 and
0.844 respectively for the original and the blank qubit. This experimental
value is close to the optimal theoretical value of 0.854. We have also
demonstrated how to use our phase-covariant cloning machine for quantum
simulations of bit by bit eavesdropping in the four-state quantum key
distribution protocol.Comment: 4 pages, 5 figure
Analyzing powers in inclusive pion production at high energy and the nucleon spin structure
Analyzing powers in inclusive pion production in high energy transversely
polarized proton-proton collisions are studied theoretically in the framework
of the quark recombination model. Calculations by assuming the SU(6)
spin-flavor symmetry for the nucleon structure disagree with the experiments.
We solve this difficulty by taking into account the %We overcome this
difficulty by taking into account the realistic spin distribution functions of
the nucleon, which differs from the SU(6) expectation at large , %but
coincides with a perturbative QCD constraint on the ratio of the unpolarized
valence distributions, as . We also discuss the kaon spin
asymmetry and find in the polarized proton-proton
collisions at large .Comment: 13 pages, 4 figures, late
Black Hole Production by Cosmic Rays
Ultra-high energy cosmic rays create black holes in scenarios with extra
dimensions and TeV-scale gravity. In particular, cosmic neutrinos will produce
black holes deep in the atmosphere, initiating quasi-horizontal showers far
above the standard model rate. At the Auger Observatory, hundreds of black hole
events may be observed, providing evidence for extra dimensions and the first
opportunity for experimental study of microscopic black holes. If no black
holes are found, the fundamental Planck scale must be above 2 TeV for any
number of extra dimensions.Comment: 4 pages, 4 figures, PRL versio
Dynamics of confined water reconstructed from inelastic x-ray scattering measurements of bulk response functions
Nanoconfined water and surface-structured water impacts a broad range of fields. For water confined between hydrophilic surfaces, measurements and simulations have shown conflicting results ranging from “liquidlike” to “solidlike” behavior, from bulklike water viscosity to viscosity orders of magnitude higher. Here, we investigate how a homogeneous fluid behaves under nanoconfinement using its bulk response function: The Green's function of water extracted from a library of S(q,ω) inelastic x-ray scattering data is used to make femtosecond movies of nanoconfined water. Between two confining surfaces, the structure undergoes drastic changes as a function of surface separation. For surface separations of ≈9 Å, although the surface-associated hydration layers are highly deformed, they are separated by a layer of bulklike water. For separations of ≈6 Å, the two surface-associated hydration layers are forced to reconstruct into a single layer that modulates between localized “frozen’ and delocalized “melted” structures due to interference of density fields. These results potentially reconcile recent conflicting experiments. Importantly, we find a different delocalized wetting regime for nanoconfined water between surfaces with high spatial frequency charge densities, where water is organized into delocalized hydration layers instead of localized hydration shells, and are strongly resistant to `freezing' down to molecular distances (<6 Å)
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