8,572 research outputs found
Multicomputer communication system
A local area network is provided for a plurality of autonomous computers which operate at different rates and under different protocols coupled by network bus adapters to a global bus. A host computer (HC) divides a message file to be transmitted into blocks, each with a header that includes a data type identifier and a trailer. The associated network bus adapter (NBA) then divides the data into packets, each with a header to which a transport header and trailer is added with frame type code which specifies one of three modes of addressing in the transmission of data, namely a physical address mode for computer to computer transmission using two bytes for source and destination addresses, a logical address mode and a data type mode. In the logical address mode, one of the two addressing bytes contains a logical channel number (LCN) established between the transmitting and one or more receiving computers. In the data type mode, one of the addressing bytes contains a code identifying the type of data
High frequency occurrence of single cotyledonary embryo morphotype and repetitive somatic embryogenesis in ‘Thompson Seedless’ crossed with seven grapevine male parents
Direct somatic embryogenesis was observed in zygotic embryos rescued from intra- and inter-specific crosses between ‘Thompson Seedless’ and seven male parents of grapevine when the embryos were cultured on Woody Plant Medium (WPM) supplemented with benzyladenine (1 μM). Repetitive somatic embryogenesis occurred on the same medium, which also supported a high percentage of embryo maturation, germination and plantlet development. The cultures retained embryogenic potential for more than two years. We observed a high frequency occurrence of monocotyledonous embryo morphotype and other morphological variations in somatic embryos of all the crosses. The percentage of embryos having mono-, di-, tri-, multiple and abnormal cotyledons varied among the crosses. The overall percentage of monocot embryos was 35.50 %, as against 38.64 % of dicot embryos, while the germination rates for mono- and dicot- embryos were 24.44 % and 24.15 %, respectively. Shoot development was poor in tri- and multiple-cotyledonary embryos, while there was no shoot formation in abnormal embryos. We assume that the relatively high occurrence of single cotyledonary morphotype may be due to the repetitive exposure of embryogenic tissues to a medium containing benzyladenine
Two-dimensional nonlinear vector states in Bose-Einstein condensates
Two-dimensional (2D) vector matter waves in the form of soliton-vortex and
vortex-vortex pairs are investigated for the case of attractive intracomponent
interaction in two-component Bose-Einstein condensates. Both attractive and
repulsive intercomponent interactions are considered. By means of a linear
stability analysis we show that soliton-vortex pairs can be stable in some
regions of parameters while vortex-vortex pairs turn out to be always unstable.
The results are confirmed by direct numerical simulations of the 2D coupled
Gross-Pitaevskii equations.Comment: 6 pages, 9 figure
The ground state of binary systems with a periodic modulation of the linear coupling
We consider a quasi-one-dimensional two-component systm, described by a pair
of Nonlinear Schr\"{o}dinger/Gross-Pitaevskii Equations (NLSEs/GPEs), which are
coupled by the linear mixing, with local strength , and by the
nonlinear incoherent interaction. We assume the self-repulsive nonlinearity in
both components, and include effects of a harmonic trapping potential. The
model may be realized in terms of periodically modulated slab waveguides in
nonlinear optics, and in Bose-Einstein condensates too. Depending on the
strengths of the linear and nonlinear couplings between the components, the
ground states (GSs) in such binary systems may be symmetric or asymmetric. In
this work, we introduce a periodic spatial modulation of the linear coupling,
making an odd, or even function of the coordinate. The sign flips of
strongly modify the structure of the GS in the binary system, as
the relative sign of its components tends to lock to the local sign of . Using a systematic numerical analysis, and an analytical approximation, we
demonstrate that the GS of the trapped system contains one or several kinks
(dark solitons) in one component, while the other component does not change its
sign. Final results are presented in the form of maps showing the number of
kinks in the GS as a function of the system's parameters, with the odd/even
modulation function giving rise to the odd/even number of the kinks. The
modulation of also produces a strong effect on the transition
between states with nearly equal and strongly unequal amplitudes of the two
components.Comment: 8 pages, 3 figure
Ginzburg-Landau equation bound to the metal-dielectric interface and transverse nonlinear optics with amplified plasmon polaritons
Using a multiple-scale asymptotic approach, we have derived the complex cubic
Ginzburg-Landau equation for amplified and nonlinearly saturated surface
plasmon polaritons propagating and diffracting along a metal-dielectric
interface. An important feature of our method is that it explicitly accounts
for nonlinear terms in the boundary conditions, which are critical for a
correct description of nonlinear surface waves. Using our model we have
analyzed filamentation and discussed bright and dark spatially localized
structures of plasmons.Comment: http://link.aps.org/doi/10.1103/PhysRevA.81.03385
The Gordon-Haus effect for modified NLS solitons
Random jitter in the soliton arrival time (the Gordon-Haus effect) is
analyzed for solitons being solutions of the integrable modified nonlinear
Schroedinger equation. It is shown that the mean square fluctuation of the
soliton position depends on the soliton parameters which can be properly
adjusted to suppress the Gordon-Haus jitter.Comment: LaTeX, 7 pages, 3 figures, to be published in Europhys. Let
A pulsed atomic soliton laser
It is shown that simultaneously changing the scattering length of an
elongated, harmonically trapped Bose-Einstein condensate from positive to
negative and inverting the axial portion of the trap, so that it becomes
expulsive, results in a train of self-coherent solitonic pulses. Each pulse is
itself a non-dispersive attractive Bose-Einstein condensate that rapidly
self-cools. The axial trap functions as a waveguide. The solitons can be made
robustly stable with the right choice of trap geometry, number of atoms, and
interaction strength. Theoretical and numerical evidence suggests that such a
pulsed atomic soliton laser can be made in present experiments.Comment: 11 pages, 4 figure
Multiple hydrodynamical shocks induced by Raman effect in photonic crystal fibres
We theoretically predict the occurrence of multiple hydrodynamical-like shock
phenomena in the propagation of ultrashort intense pulses in a suitably
engineered photonic crystal fiber. The shocks are due to the Raman effect,
which acts as a nonlocal term favoring their generation in the focusing regime.
It is shown that the problem is mapped to shock formation in the presence of a
slope and a gravity-like potential. The signature of multiple shocks in XFROG
signals is unveiled
Nonlinear wavelength conversion in photonic crystal fibers with three zero dispersion points
In this theoretical study, we show that a simple endlessly single-mode
photonic crystal fiber can be designed to yield, not just two, but three
zero-dispersion wavelengths. The presence of a third dispersion zero creates a
rich phase-matching topology, enabling enhanced control over the spectral
locations of the four-wave-mixing and resonant-radiation bands emitted by
solitons and short pulses. The greatly enhanced flexibility in the positioning
of these bands has applications in wavelength conversion, supercontinuum
generation and pair-photon sources for quantum optics
More Signatures of the Intermediate Mass Higgs Boson
We examine the potential signatures of the Higgs boson when it decays into a
tau-lepton pair. We show that with the proper identification of the tau-jet,
this decay mode can lead to the identification of the Higgs boson over most of
the intermediate mass range (\mW \mH 2 \mW).Comment: 10 pages, LaTeX fil
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