Scattering of dislocated wavefronts by vertical vorticity and the Aharonov-Bohm effect II: Dispersive waves

Previous results on the scattering of surface waves by vertical vorticity on shallow water are generalized to the case of dispersive water waves. Dispersion effects are treated perturbatively around the shallow water limit, to first order in the ratio of depth to wavelength. The dislocation of the incident wavefront, analogous to the Aharonov-Bohm effect, is still observed. At short wavelengths the scattering is qualitatively similar to the nondispersive case. At moderate wavelengths, however, there are two markedly different scattering regimes according to wether the capillary length is smaller or larger than $\sqrt{3}$ times depth. The dislocation is characterized by a parameter that depends both on phase and group velocity. The validity range of the calculation is the same as in the shallow water case: wavelengths small compared to vortex radius, and low Mach number. The implications of these limitations are carefully considered.Comment: 30 pages, 11 figure

Two-dimensional macroscopic quantum dynamics in YBCO Josephson junctions

We theoretically study classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a YBCO Josephson junction coupled with an LC circuit. The TA and MQT escape rate are calculated by taking into account the two-dimensional nature of the classical and quantum phase dynamics. We find that the MQT escape rate is largely suppressed by the coupling to the LC circuit. On the other hand, this coupling leads to the slight reduction of the TA escape rate. These results are relevant for the interpretation of a recent experiment on the MQT and TA phenomena in YBCO bi-epitaxial Josephson junctions.Comment: 9 pages, 2 figure

Experimental Study of Parametric Autoresonance in Faraday Waves

The excitation of large amplitude nonlinear waves is achieved via parametric autoresonance of Faraday waves. We experimentally demonstrate that phase locking to low amplitude driving can generate persistent high-amplitude growth of nonlinear waves in a dissipative system. The experiments presented are in excellent agreement with theory.Comment: 4 pages, 4 eps figures, to appear in Phys. Rev. Let

Theory of Macroscopic Quantum Tunneling in High-T_c c-Axis Josephson Junctions

We study macroscopic quantum tunneling (MQT) in c-axis twist Josephson junctions made of high-T_c superconductors in order to clarify the influence of the anisotropic order parameter symmetry (OPS) on MQT. The dependence of the MQT rate on the twist angle $\gamma$ about the c-axis is calculated by using the functional integral and the bounce method. Due to the d-wave OPS, the $\gamma$ dependence of standard deviation of the switching current distribution and the crossover temperature from thermal activation to MQT are found to be given by $\cos2\gamma$ and $\sqrt{\cos2\gamma}$, respectively. We also show that a dissipative effect resulting from the nodal quasiparticle excitation on MQT is negligibly small, which is consistent with recent MQT experiments using Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8 + \delta}$ intrinsic junctions. These results indicate that MQT in c-axis twist junctions becomes a useful experimental tool for testing the OPS of high-T_c materials at low temperature, and suggest high potential of such junctions for qubit applications.Comment: 15 pages, 8 figures, 1 tabl

Impurity-induced stabilization of solitons in arrays of parametrically driven nonlinear oscillators

Chains of parametrically driven, damped pendula are known to support soliton-like clusters of in-phase motion which become unstable and seed spatiotemporal chaos for sufficiently large driving amplitudes. We show that the pinning of the soliton on a "long" impurity (a longer pendulum) expands dramatically its stability region whereas "short" defects simply repel solitons producing effective partition of the chain. We also show that defects may spontaneously nucleate solitons.Comment: 4 pages in RevTeX; 7 figures in ps forma

Travelling solitons in the parametrically driven nonlinear Schroedinger equation

We show that the parametrically driven nonlinear Schroedinger equation has wide classes of travelling soliton solutions, some of which are stable. For small driving strengths nonpropogating and moving solitons co-exist while strongly forced solitons can only be stably when moving sufficiently fast.Comment: The paper is available as the JINR preprint E17-2000-147(Dubna, Russia) and the preprint of the Max-Planck Institute for the Complex Systems mpipks/0009011, Dresden, Germany. It was submitted to Physical Review

Siting Process for HLW Repository in Japan

In the year 2000, the geological disposal program for high-level radioactive waste in Japan moved from the phase of generic research and development (R&D) into the phase of implementation. Following legislation entitled the ''Specified Radioactive Waste Final Disposal Act'', the Nuclear Waste Management Organization of Japan (NUMO) was established as the implementing organization. The assigned activities of NUMO include selection of the repository site, demonstration of disposal technology at the site, developing relevant licensing applications and construction, operation and closure of the repository. As the first milestone of siting process, NUMO announced to the public an overall procedure for selection of preliminary investigation areas for potential candidate sites on October 29, 2001. The procedure specifies that NUMO will solicit volunteer municipalities for preliminary investigation areas with publishing four documents as an information package. These documents are tentatively entitled ''Instructions for Application'', ''Siting Factors for the Preliminary Investigation Areas'', a ''Repository Concepts'' as well as an ''Site Investigation Community Outreach Scheme''

Integrable semi-discretization of the coupled nonlinear Schr\"{o}dinger equations

A system of semi-discrete coupled nonlinear Schr\"{o}dinger equations is studied. To show the complete integrability of the model with multiple components, we extend the discrete version of the inverse scattering method for the single-component discrete nonlinear Schr\"{o}dinger equation proposed by Ablowitz and Ladik. By means of the extension, the initial-value problem of the model is solved. Further, the integrals of motion and the soliton solutions are constructed within the framework of the extension of the inverse scattering method.Comment: 27 pages, LaTeX2e (IOP style

Inferior oblique muscle of the eye: its fetal development with special reference to understanding of the frequent variants in adults

To provide better understanding of frequent variations of the inferior oblique (IO) of adult extraocular muscles, we observed sagittal and horizontal histological sections of the eye and orbits from 32 fetuses (approximately 7-34 weeks of gestational age; 24-295 mm of crown-rump length). In early fetuses (7-8 weeks), the IO was restricted at an antero-infero-medial angle of the future orbit. In contrast to extraocular recti, the IO appeared to extend along the mediolateral axis and had no definite tendon. At midterm, the IO tendon became evident. Sometimes, the IO muscle belly attached to the inferior rectus or, the IO tendon divided into two laminae to enclose the lateral rectus. At late-term, a multilayered sheath was evident around the sclera and, via one or some of the fascial layers, the IO was communicated with a fascia enclosing the inferior rectus. At midterm and late-term, the IO originated not only from the maxilla near the orbicularis oculi origin but also from a vein-rich fibrous tissue around the lacrimal sac. Both origins were muscular without intermittent tendon or ligament. Therefore, the fascial connection as well as a direct contact between the IO and the inferior or lateral rectus seemed to provide variant muscular bridges as reported in adults. Moreover, the two attachment sites at the origin seemed to provide double muscle bellies of the adult IO. Consequently, the present specimens contained seeds of any types of adult variations. The muscle fibers from the lacrimal sac might play a role for the lacrimal drainage

Adaptive regulation of membrane lipids and fluidity during thermal acclimation in Tetrahymena

The free-living eukaryotic protozoan Tetrahymena is a potentially useful model for the thermoadaptive membrane regulation because of easy growth in the axenic culture, systematic isolation of subcellular organelles, and quick response to temperature stress. Exposure of Tetrahymena cells to the cold temperature induces marked alterations in the lipid composition and the physical properties (fluidity) of various membranes. The increase in fatty acid unsaturation of membrane phospholipids is required to preserve the proper fluidity. In this homeoviscous adaptive response, acyl-CoA desaturase plays a pivotal role and its activity is regulated by induction of the enzyme via transcriptional activation