On the troll line investigations off Cochin during five fishing seasons. Pt. 2. Investigations during 1963-64 season

During this season the investigations were mainly directed towards elucidation of the selective action of trolling lures. Feather jigs, buffalo horn jigs, stainless steel jigs, Japanese whale bone jigs and plastic jigs were selected. Operations were carried out from Fisheries technology No. 5

Decay of Quasi-Particle in a Quantum Dot: the role of Energy Resolution

The disintegration of quasiparticle in a quantum dot due to the electron interaction is considered. It was predicted recently that above the energy \eps^{*} = \Delta(g/\ln g)^{1/2} each one particle peak in the spectrum is split into many components ($\Delta$ and $g$ are the one particle level spacing and conductance). We show that the observed value of \eps^{*} should depend on the experimental resolution \delta \eps. In the broad region of variation of \delta \eps the $\ln g$ should be replaced by \ln(\Delta/ g\delta \eps). We also give the arguments against the delocalization transition in the Fock space. Most likely the number of satellite peaks grows continuously with energy, being $\sim 1$ at \eps \sim \eps^{*}, but remains finite at \eps > \eps^{*}. The predicted logarithmic distribution of inter-peak spacings may be used for experimental confirmation of the below-Golden-Rule decay.Comment: 5 pages, REVTEX, 2 eps figures, version accepted for publication in Phys. Rev. Let

Very-wide-field camera. Proposal of Space Astronomy Laboratory for second Spacelab mission

A proposal is made for inclusion of a very wide field camera onboard Spacelab. Its scientific program is outlined: detection and photometry, spectrography, and star and starlike object photography. The optics, receptor, and mechanical structure are described. Scientific and technical constraints are discussed, and a development plan is detailed. The dust contamination of Spacelab using the camera was also studied

Properties of low-lying states in a diffusive quantum dot and Fock-space localization

Motivated by an experiment by Sivan et al. (Europhys. Lett. 25, 605 (1994)) and by subsequent theoretical work on localization in Fock space, we study numerically a hierarchical model for a finite many-body system of Fermions moving in a disordered potential and coupled by a two-body interaction. We focus attention on the low-lying states close to the Fermi energy. Both the spreading width and the participation number depend smoothly on excitation energy. This behavior is in keeping with naive expectations and does not display Anderson localization. We show that the model reproduces essential features of the experiment by Sivan et al.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let

Time-reversal in dynamically-tuned zero-gap periodic systems

We show that short pulses propagating in zero-gap periodic systems can be reversed with 100% efficiency by using weak non-adiabatic tuning of the wave velocity at time-scales that can be much slower than the period. Unlike previous schemes, we demonstrate reversal of {\em broadband} (few cycle) pulses with simple structures. Our scheme may thus open the way to time-reversal in a variety of systems for which it was not accessible before.Comment: Accepted for publication in Phys. Rev. Letter

On the selective action of the cod end meshes of a shrimp trawl

Selectivity studies using cod end and cover to determine the optimum cod end mesh size for commercial size groups of shrimps was carried out at Cochin during 1963-64 fishing season. The normality of the result was checked by trouser cod end method. Although the present investigation was mainly aimed to find out suitable cod end mesh size for commercial varieties of shrimps, five commonly occurring species of fishes were also taken. The 50% escape level, co-efficient of selectivity and selection factor for all the species were worked out. From the findings, the authors stress the necessity of increasing the cod end mesh size from the present condition (25.4 to 31.70 mm) to 41.65 mm fabricated mesh size to avoid depletion of the natural population

Spatial distribution of unidentified infrared bands and extended red emission in the compact galactic HII region Sh 152

We present visible and near IR images of the compact HII region Sh 152. Some of these images reveal the presence of Extended Red Emission (ERE) around 698 nm and emission from Unidentified Infra Red Bands (UIRBs) at 3.3 and 6.2 micron. Other images show the near infrared (7-12 micron) continuous emission of the nebula. The ERE emission is found to coincide with the ionized region and significantly differ from the UIRBs location. Also some evidence is found in favor of grains as carriers for ERE.Comment: 3 pages, 4 figures, to be published in the proceedings of the colloquium "The universe as seen by ISO" help in Paris, October 20-23, 1998 ; available in html format at http://www.obs-hp.fr/preprints.htm