4,414 research outputs found
Margarita Denenburg, piano
Johann Sebastian BachWolfgang Amadeus MozartClaude DebussyRobert Schuman
Stable periodic waves in coupled Kuramoto-Sivashinsky - Korteweg-de Vries equations
Periodic waves are investigated in a system composed of a
Kuramoto-Sivashinsky - Korteweg-de Vries (KS-KdV) equation, which is linearly
coupled to an extra linear dissipative equation. The model describes, e.g., a
two-layer liquid film flowing down an inclined plane. It has been recently
shown that the system supports stable solitary pulses. We demonstrate that a
perturbation analysis, based on the balance equation for the field momentum,
predicts the existence of stable cnoidal waves (CnWs) in the same system. It is
found that the mean value U of the wave field u in the main subsystem, but not
the mean value of the extra field, affects the stability of the periodic waves.
Three different areas can be distinguished inside the stability region in the
parameter plane (L,U), where L is the wave's period. In these areas, stable
are, respectively, CnWs with positive velocity, constant solutions, and CnWs
with negative velocity. Multistability, i.e., the coexistence of several
attractors, including the waves with several maxima per period, appears at
large value of L. The analytical predictions are completely confirmed by direct
simulations. Stable waves are also found numerically in the limit of vanishing
dispersion, when the KS-KdV equation goes over into the KS one.Comment: a latex text file and 16 eps files with figures. Journal of the
Physical Society of Japan, in pres
Stabilized Kuramoto-Sivashinsky system
A model consisting of a mixed Kuramoto - Sivashinsky - KdV equation, linearly
coupled to an extra linear dissipative equation, is proposed. The model applies
to the description of surface waves on multilayered liquid films. The extra
equation makes its possible to stabilize the zero solution in the model,
opening way to the existence of stable solitary pulses (SPs). Treating the
dissipation and instability-generating gain in the model as small
perturbations, we demonstrate that balance between them selects two
steady-state solitons from their continuous family existing in the absence of
the dissipation and gain. The may be stable, provided that the zero solution is
stable. The prediction is completely confirmed by direct simulations. If the
integration domain is not very large, some pulses are stable even when the zero
background is unstable. Stable bound states of two and three pulses are found
too. The work was supported, in a part, by a joint grant from the Israeli
Minsitry of Science and Technology and Japan Society for Promotion of Science.Comment: A text file in the latex format and 20 eps files with figures.
Physical Review E, in pres
THE LEARNING PROCESS OF UNIFORMITY SKILLS FOR NOVICE ROWERS
In the crew events which row with a number of rowers, it is thought that the important technical element is the uniformity of crew how well rowers can synchronize timing of movement oars (Wing AM & Woodburn C, 1995; A Baudouin & D Hawkins, 2004). The highly uniformity skills also could make up for the total low power in the crew. In case of instruction for novice rowers, due to enhancement of uniformity skills, they may be able to feel the sensation of propulsive force of boat. Therefore, it is thought that this sensation would affect their interests in rowing. The purpose of this study was to identify the learning process of uniformity skills for novice rowers, and to obtain the basic data to instruct for novice rowers
X-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301
Content: We present the results from observations of the merging
cluster of galaxies CIZA J2242.8+5301 at =0.192. Aims. To study the physics
of gas heating and particle acceleration in cluster mergers, we investigated
the X-ray emission from CIZA J2242.8+5301, which hosts two giant radio relics
in the northern/southern part of the cluster. Methods. We analyzed data from
three-pointed Suzaku observations of CIZA J2242.8+5301 to derive the
temperature distribution in four different directions. Results: The
Intra-Cluster Medium (ICM) temperature shows a remarkable drop from
8.5 keV to 2.7 keV across the northern radio
relic. The temperature drop is consistent with a Mach number and a shock velocity
. We also confirm the
temperature drop across the southern radio relic. However, the ICM temperature
beyond this relic is much higher than beyond the northern one, which gives a
Mach number and shock velocity
. These results agree with
other systems showing a relationship between the radio relics and shock fronts
which are induced by merging activity. We compare the X-ray derived Mach
numbers with the radio derived Mach numbers from the radio spectral index under
the assumption of diffusive shock acceleration in the linear test particle
regime. For the northern radio relic, the Mach numbers derived from X-ray and
radio observations agree with each other. Based on the shock velocities, we
estimate that CIZA J2242.8+5301 is observed approximately 0.6 Gyr after core
passage. The magnetic field pressure at the northern relic is estimated to be
9% of the thermal pressure.Comment: 12 pages, 10 figures, A&A accepte
Mitochondrial haplogroups associated with elite Japanese athlete status
Purpose It has been hypothesised that certain mitochondrial haplogroups, which are defined by the presence of a characteristic cluster of tightly linked mitochondrial DNA polymorphisms, would be associated with elite Japanese athlete status. To examine this hypothesis, the frequencies of mitochondrial haplogroups found in elite Japanese athletes were compared with those in the general Japanese population. Methods Subjects comprised 139 Olympic athletes (79 endurance/middle-power athletes (EMA), 60 sprint/power athletes (SPA)) and 672 controls (CON). Two mitochondrial DNA fragments containing the hypervariable sequence I (m16024-m16383) of the major non-coding region and the polymorphic site at m. 5178C>A within the NADH dehydrogenase subunit 2 gene were sequenced, and subjects were classified into 12 major mitochondrial haplogroups (ie, F, B, A, N9a, N9b, M7a, M7b, M*, G2, G1, D5 or D4). The mitochondrial haplogroup frequency differences among EMA, SPA and CON were then examined. Results EMA showed an excess of haplogroup G1 (OR 2.52, 95% CI 1.05 to 6.02, p=0.032), with 8.9% compared with 3.7% in CON, whereas SPA displayed a greater proportion of haplogroup F (OR 2.79, 95% CI 1.28 to 6.07, p=0.007), with 15.0% compared with 6.0% in CON. Conclusions The results suggest that mitochondrial haplogroups G1 and F are associated with elite EMA and SPA status in Japanese athletes, respectivel
Smearing Effect in Plane-Wave Matrix Model
Motivated by the usual D2-D0 system, we consider a configuration composed of
flat membrane and fuzzy sphere membrane in plane-wave matrix model, and
investigate the interaction between them. The configuration is shown to lead to
a non-trivial interaction potential, which indicates that the fuzzy sphere
membrane really behaves like a graviton, giant graviton. Interestingly, the
interaction is of r^{-3} type rather than r^{-5} type. We interpret it as the
interaction incorporating the smearing effect due to the fact that the
considered supersymmetric flat membrane should span and spin in four
dimensional subspace of plane-wave geometry.Comment: 26 pages; added referenc
Dependence of the Particle Confinement Coefficients on the Magnetic Field Configuration on LHD
Whisper-to-speech conversion using restricted Boltzmann machine arrays
Whispers are a natural vocal communication mechanism, in which vocal cords do not vibrate normally. Lack of glottal-induced pitch leads to low energy, and an inherent noise-like spectral distribution reduces intelligibility. Much research has been devoted to processing of whispers, including conversion of whispers to speech. Unfortunately, among several approaches, the best reconstructed speech to date still contains obviously artificial muffles and suffers from an unnatural prosody. To address these issues, the novel use of multiple restricted Boltzmann machines (RBMs) is reported as a statistical conversion model between whisper and speech spectral envelopes. Moreover, the accuracy of estimated pitch is improved using machine learning techniques for pitch estimation within only voiced (V) regions. Both objective and subjective evaluations show that this new method improves the quality of whisper-reconstructed speech compared with the state-of-the-art approaches
Studies of Phase Turbulence in the One Dimensional Complex Ginzburg-Landau Equation
The phase-turbulent (PT) regime for the one dimensional complex
Ginzburg-Landau equation (CGLE) is carefully studied, in the limit of large
systems and long integration times, using an efficient new integration scheme.
Particular attention is paid to solutions with a non-zero phase gradient. For
fixed control parameters, solutions with conserved average phase gradient
exist only for less than some upper limit. The transition from phase to
defect-turbulence happens when this limit becomes zero. A Lyapunov analysis
shows that the system becomes less and less chaotic for increasing values of
the phase gradient. For high values of the phase gradient a family of
non-chaotic solutions of the CGLE is found. These solutions consist of
spatially periodic or aperiodic waves travelling with constant velocity. They
typically have incommensurate velocities for phase and amplitude propagation,
showing thereby a novel type of quasiperiodic behavior. The main features of
these travelling wave solutions can be explained through a modified
Kuramoto-Sivashinsky equation that rules the phase dynamics of the CGLE in the
PT phase. The latter explains also the behavior of the maximal Lyapunov
exponents of chaotic solutions.Comment: 16 pages, LaTeX (Version 2.09), 10 Postscript-figures included,
submitted to Phys. Rev.
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