Out-of-phase oscillation between superfluid and thermal components for a trapped Bose condensate under oscillatory excitation

The vortex nucleation and the emergence of quantum turbulence induced by oscillating magnetic fields, introduced by Henn E A L, et al. 2009 (Phys. Rev. A 79, 043619) and Henn E A L, et al. 2009 (Phys. Rev. Lett. 103, 045301), left a few open questions concerning the basic mechanisms causing those interesting phenomena. Here, we report the experimental observation of the slosh dynamics of a magnetically trapped $^{87}$Rb Bose-Einstein condensate (BEC) under the influence of a time-varying magnetic field. We observed a clear relative displacement in between the condensed and the thermal fraction center-of-mass. We have identified this relative counter move as an out-of-phase oscillation mode, which is able to produce ripples on the condensed/thermal fractions interface. The out-of-phase mode can be included as a possible mechanism involved in the vortex nucleation and further evolution when excited by time dependent magnetic fields.Comment: 5 pages, 5 figures, 25 reference

Fast transform decoding of nonsystematic Reed-Solomon codes

A Reed-Solomon (RS) code is considered to be a special case of a redundant residue polynomial (RRP) code, and a fast transform decoding algorithm to correct both errors and erasures is presented. This decoding scheme is an improvement of the decoding algorithm for the RRP code suggested by Shiozaki and Nishida, and can be realized readily on very large scale integration chips

Green leaf volatiles affect the resveratrol production stimulated by ultraviolet C irradiation in grape leaf discs

The effect of green leaf volatiles (GLVs; cis-3-hexenol and trans-2-hexenal) on the resveratrol production stimulated and nonstimulated by ultraviolet C (UV-C) irradiation was elucidated in the leaf discs of ‘Delaware’ grapes. Each GLV treatment slightly reduced resveratrol levels in the leaf discs. Pretreatment with cis-3-hexenol inhibited the resveratrol accumulation stimulated by UV-C irradiation irrespective of the concentration. On the other hand, pretreatment with trans-2-hexenal at low concentration augmented the levels of resveratrol increased by UV-C irradiation. These results suggest that trans-2-hexenal had a priming effect on the resveratrol accumulation stimulated by UV-C irradiation in grape leaf discs. The highest priming effect of trans-2-hexenal was found at 2.58 μM for 24 h exposure. Exposure times, from 2 to 24 h, of 4.3 μM trans-2-hexenal did not change the priming effect.

A sensitive study of real time storm surge forecast model to meteorological and hydrodynamic fields along the Sanin coast, Japan

In the present study, the performance of the real time storm surge forecast model based on the neural network is examined by forecasting Typhoon Megi storm surge 2003 at Sakai, Japan in terms of a variety of the combinations of data obtained from Typhoons Songda 2004 and Maemi 2003. In the experiments, the data sets are trained with the meteorological data measured at five stations: the sea level pressure, the depression rate of the sea level pressure, the wind speed, the wind direction; the hydroulic data: the sea surface level and the storm surge at Sakai; the typhoon parameters: the typhoon position, the central pressure of the typhoon and the highest wind speed near the typhoon center. In addition, the forecast time spans of 01, 02, 03, 04, 05, 12 and 24 hours are investigated for all cases of the data sets. From the results, It is found that the performance of the real time forecast models shows best when training the neural network with the data set of the storm surge, the sea level pressure, the depression rates of the sea level pressure, the wind speed and the typhoon position at Sakai

Photoassociative ionization of Na inside a storage ring

Motivated by recent interest in low dimensional arrays of atoms, we experimentally investigated the way cold collisional processes are affected by the geometry of the considered atomic sample. More specifically, we studied the case of photoassociative ionization (PAI) both in a storage ring where collision is more unidirectional in character and in a trap with clear undefinition of collision axis. First, creating a ring shaped trap (atomotron) we investigated two-color PAI dependence with intensity and polarization of a probing laser. The intensity dependence of the PAI rate was also measured in a magneto-optical trap presenting equivalent temperature and density conditions. Indeed, the results show that in the ring trap, the value of the PAI rate constant is much lower and does not show evidences of saturation, unlike in the case of the 3D-MOT. Cold atomic collisions in storage ring may represent new possibilities for study.Comment: 5 pages, 5 figures; Accepted by Optics Communicatio

Myogenesis in vitro as Seen with the Scanning Electron Microscope

In this paper, we review our recent observations by scanning electron microscopy (SEM) on the differentiation of the cell surface and cytoplasmic organelles in embryonic chick skeletal muscle cells in vitro. The changes of the surface structures of myoblasts during mitosis were essentially similar to those of other cell types, but the characteristic spindle shape of myoblasts did not change throughout most of this period. Cytoskeletal structures under the sarcolemma were examined by Triton extraction and metal coating. Cells in S, G2 and M possessed a dense, and those in G1 a loose filament network under the membrane. Myotubes possessed a dense network under the sarcolemma. In the fusion area between a myoblast and a myotube, the cytoskeletal domain of the former could be distinguished from the latter because of the mosaic appearance of the subsarcolemmal cytoskeletal network. This net-work was composed predominantly of 10-13 nm filaments; they were identified as actin filaments because of their decoration with myosin subfragment-1. Triton treatment and thiocarbohydrazideosmium staining allowed us to visualize myofibrils. They ran in the direction of inferred stress lines brought about by elongation and adhesion of the cells to substrate. Intracellular membranous organelles could be seen by the freeze-polishing and osmium-maceration procedure. Mitochondria exhibited complex irregular branchings. T system tubules ran a tortuous course. Sarcoplasmic reticula with occasional dilatations were connected to each other. The results are of sufficient promise to encourage more extensive analysis of myogenesis by SEM

Route to turbulence in a trapped Bose-Einstein condensate

We have studied a Bose-Einstein condensate of $^{87}Rb$ atoms under an oscillatory excitation. For a fixed frequency of excitation, we have explored how the values of amplitude and time of excitation must be combined in order to produce quantum turbulence in the condensate. Depending on the combination of these parameters different behaviors are observed in the sample. For the lowest values of time and amplitude of excitation, we observe a bending of the main axis of the cloud. Increasing the amplitude of excitation we observe an increasing number of vortices. The vortex state can evolve into the turbulent regime if the parameters of excitation are driven up to a certain set of combinations. If the value of the parameters of these combinations is exceeded, all vorticity disappears and the condensate enters into a different regime which we have identified as the granular phase. Our results are summarized in a diagram of amplitude versus time of excitation in which the different structures can be identified. We also present numerical simulations of the Gross-Pitaevskii equation which support our observations.Comment: 6 pages, 3 figure