11,327 research outputs found
Multiobjective synchronization of coupled systems
Copyright @ 2011 American Institute of PhysicsSynchronization of coupled chaotic systems has been a subject of great interest and importance, in theory but also various fields of application, such as secure communication and neuroscience. Recently, based on stability theory, synchronization of coupled chaotic systems by designing appropriate coupling has been widely investigated. However, almost all the available results have been focusing on ensuring the synchronization of coupled chaotic systems with as small coupling strengths as possible. In this contribution, we study multiobjective synchronization of coupled chaotic systems by considering two objectives in parallel, i. e., minimizing optimization of coupling strength and convergence speed. The coupling form and coupling strength are optimized by an improved multiobjective evolutionary approach. The constraints on the coupling form are also investigated by formulating the problem into a multiobjective constraint problem. We find that the proposed evolutionary method can outperform conventional adaptive strategy in several respects. The results presented in this paper can be extended into nonlinear time-series analysis, synchronization of complex networks and have various applications
L^p boundedness of the wave operator for the one dimensional Schroedinger operator
Given a one dimensional perturbed Schroedinger operator H=-(d/dx)^2+V(x) we
consider the associated wave operators W_+, W_- defined as the strong L^2
limits as s-> \pm\infty of the operators e^{isH} e^{-isH_0} We prove that the
wave operators are bounded operators on L^p for all 1<p<\infty, provided
(1+|x|)^2 V(x) is integrable, or else (1+|x|)V(x) is integrable and 0 is not a
resonance. For p=\infty we obtain an estimate in terms of the Hilbert
transform. Some applications to dispersive estimates for equations with
variable rough coefficients are given.Comment: 26 page
The Origin of the Electromagnetic Interaction in Einstein's Unified Field Theory with Sources
Einstein's unified field theory is extended by the addition of matter terms
in the form of a symmetric energy tensor and of two conserved currents. From
the field equations and from the conservation identities emerges the picture of
a gravoelectrodynamics in a dynamically polarizable Riemannian continuum.
Through an approximate calculation exploiting this dynamical polarizability it
is argued that ordinary electromagnetism may be contained in the theory.Comment: 8 pages. Misprint in eq. 15 correcte
Olefin Hydroarylation Catalyzed by (pyridyl-indolate)Pt(II) Complexes: Catalytic Efficiencies and Mechanistic Aspects
Symmetries and novel universal properties of turbulent hydrodynamics in a symmetric binary fluid mixture
We elucidate the universal properties of the nonequilibrium steady states
(NESS) in a driven symmetric binary fluid mixture, an example of active
advection, in its miscible phase. We use the symmetries of the equations of
motion to establish the appropriate form of the structure functions which
characterise the statistical properties of the NESS of a driven symmetric
binary fluid mixture. We elucidate the universal properties described by the
scaling exponents and the amplitude ratios. Our results suggest that these
exponents and amplitude ratios vary continuously with the degree of
crosscorrelations between the velocity and the gradient of the concentration
fields. Furthermore, we demonstrate, in agreement with Celani et al, Phys. Rev.
Lett., 89, 234502 (2002, that the conventional structure functions as used in
passive scalar turbulence studies exhibit only simple scaling in the problem of
symmetric binary fluid mixture even in the weak concentration limit. We also
discuss possible experimental verifications of our results.Comment: To appear in JSTAT (letters) (2005
Impurity effects on the melting of Ni clusters
We demonstrate that the addition of a single carbon impurity leads to
significant changes in the thermodynamic properties of Ni clusters consisting
of more than a hundred atoms. The magnitude of the change induced is dependent
upon the parameters of the Ni-C interaction. Hence, thermodynamic properties of
Ni clusters can be effectively tuned by the addition of an impurity of a
particular type. We also show that the presence of a carbon impurity
considerably changes the mobility and diffusion of atoms in the Ni cluster at
temperatures close to its melting point. The calculated diffusion coefficients
of the carbon impurity in the Ni cluster can be used for a reliable estimate of
the growth rate of carbon nanotubes.Comment: 27 pages, 13 figure
Characterization of proliferative, glial and angiogenic responses after a CoCl2-induced injury of photoreceptor cells in the adult zebrafish retina
The adult zebrafish is considered a useful model for studying mechanisms involved in tissue growth and regeneration. We have characterized cytotoxic damage to the retina of adult zebrafish caused by the injection of cobalt chloride (CoCl2) into the vitreous cavity. The CoCl2 concentration we used primarily caused injury to photoreceptors. We observed the complete disappearance of cones, followed by rods, across the retina surface from 28 to 96 hr after CoCl2 injury. The loss of 30% of bipolar cells was also observed by 50 hr after lesion (hpl). CoCl2 injury provoked a strong induction of the proliferative activity of multipotent Müller glia and derived progenitors. The effect of CoCl2 on retina cells was significantly reduced by treatment with glutamate ionotropic receptor antagonists. Cone photoreceptor regeneration occurred 25 days after injury. Moreover, a single dose of CoCl2 induced vascular damage and regeneration, whereas three injections of CoCl2 administered weekly provoked neovascular-like changes 20 days after injury. CoCl2 injury also caused microglial reactivity in the optic disc, retina periphery and fibre layer. CoCl2-induced damage enhanced pluripotency and proneural transcription factor gene expression in the mature retina 72 hpl. Tumour necrosis factor alpha, vascular endothelial growth factor (VEGF) and VEGF receptor mRNA levels were also significantly enhanced by 72 hpl. The injury paradigm we have described in this work may be useful for the discovery of signalling molecules and pathways that participate in the regenerative response and it may serve as a model to screen for compounds that could potentially treat aberrant angiogenesis.Fil: Medrano, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Pisera Fuster, Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Sanchis, Pablo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Paez, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Bernabeu, Ramon Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Faillace, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentin
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