4,717 research outputs found
Network Synchronization in a Noisy Environment with Time Delays: Fundamental Limits and Trade-Offs
We study the effects of nonzero time delays in stochastic synchronization
problems with linear couplings in an arbitrary network. Using the known exact
threshold value from the theory of differential equations with delays, we
provide the synchronizability threshold for an arbitrary network. Further, by
constructing the scaling theory of the underlying fluctuations, we establish
the absolute limit of synchronization efficiency in a noisy environment with
uniform time delays, i.e., the minimum attainable value of the width of the
synchronization landscape. Our results have also strong implications for
optimization and trade-offs in network synchronization with delays.Comment: 3 figure
DOGME DOES HOLLYWOOD: A CASE OF MINOR CINEMA
This thesis analyzes four films by the Danish directors and founders of the Dogme 95 movement, Thomas Vinterberg and Lars von Trier. The four films were released in their post-Dogme period: It\u27s All About Love (Vinterberg, 2003), Dogville (von Trier, 2003), Manderlav (von Trier, 2005), and Dear Wendv (Vinterberg, 2005). The thesis places these films about America within the (film-)historical context of the Bush-Cheney regime\u27s hard-right agenda, and the larger context of the Hollywood films released during the period. The theory of minor cinema — inspired by Gilles Deleuze and Félix Guattari — is used to analyze the politics of space, language and perception in each of these films. The thesis argues for a new, inherently transnational use of minor cinema that accounts for Félix Guattari\u27s contributions to the theory, often eclipsed by the more widespread reception of Gilles Deleuze
Arithmetic on a Distributed-Memory Quantum Multicomputer
We evaluate the performance of quantum arithmetic algorithms run on a
distributed quantum computer (a quantum multicomputer). We vary the node
capacity and I/O capabilities, and the network topology. The tradeoff of
choosing between gates executed remotely, through ``teleported gates'' on
entangled pairs of qubits (telegate), versus exchanging the relevant qubits via
quantum teleportation, then executing the algorithm using local gates
(teledata), is examined. We show that the teledata approach performs better,
and that carry-ripple adders perform well when the teleportation block is
decomposed so that the key quantum operations can be parallelized. A node size
of only a few logical qubits performs adequately provided that the nodes have
two transceiver qubits. A linear network topology performs acceptably for a
broad range of system sizes and performance parameters. We therefore recommend
pursuing small, high-I/O bandwidth nodes and a simple network. Such a machine
will run Shor's algorithm for factoring large numbers efficiently.Comment: 24 pages, 10 figures, ACM transactions format. Extended version of
Int. Symp. on Comp. Architecture (ISCA) paper; v2, correct one circuit error,
numerous small changes for clarity, add reference
Angular distribution of positrons emitted from metal surfaces
The effect of inelastic scattering processes on the angular distribution of positrons spontaneously emitted from metal surfaces is investigated. Angular and energy spectra are calculated for positrons suffering energy loss due to electron-hole excitation in emission from materials with low (aluminum) and high (tungsten) positron work functions.Peer reviewe
The tensor part of the Skyrme energy density functional. III. Time-odd terms at high spin
This article extends previous studies on the effect of tensor terms in the
Skyrme energy density functional by breaking of time-reversal invariance. We
have systematically probed the impact of tensor terms on properties of
superdeformed rotational bands calculated within the cranked
Hartree-Fock-Bogoliubov approach for different parameterizations covering a
wide range of values for the isoscalar and isovector tensor coupling constants.
We analyze in detail the contribution of the tensor terms to the energies and
dynamical moments of inertia and study their impact on quasi-particle spectra.
Special attention is devoted to the time-odd tensor terms, the effect of
variations of their coupling constants and finite-size instabilities.Comment: 28 pages, 34 figure
Design and Fabrication of Three-Dimensional Scaffolds for Tissue Engineering of Human Heart Valves
We developed a new fabrication technique for 3-dimensional scaffolds for tissue engineering of human heart valve tissue. A human aortic homograft was scanned with an X-ray computer tomograph. The data derived from the X-ray computed tomogram were processed by a computer-aided design program to reconstruct a human heart valve 3-dimensionally. Based on this stereolithographic model, a silicone valve model resembling a human aortic valve was generated. By taking advantage of the thermoplastic properties of polyglycolic acid as scaffold material, we molded a 3-dimensional scaffold for tissue engineering of human heart valves. The valve scaffold showed a deviation of only +/- 3-4% in height, length and inner diameter compared with the homograft. The newly developed technique allows fabricating custom-made, patient-specific polymeric cardiovascular scaffolds for tissue engineering without requiring any suture materials. Copyright (c) 2008 S. Karger AG, Base
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