Processing and quality requirements of Beche-de-mer

This paper deals with processing, composition, common quality defects, export specifications, suggestions for improvement in the processing and finally precautions to be taken during processing

भारत की बाँगडे मात्स्यिकी की कुछ विशेषताएं

कृपया पूरा लेखा पढ

Some characteristics of the mackerel fishery in India

The recent increases in the catch of mackerel from the deeper waters of the Calicut - Cochin area indicate that the fish move down to deeper areas during summer due to the thermocline. Spreading of trawling to deeper waters, with the opening up of export market for cephalopods, can be the reason for the increased catch of mackerel by trawls. The most successful period of recruitment to the mackerel fishery coincides with upwelling (Mackerel form large shoals to feed on the plankton that is abundant due to upwelling, making surface fishery highly successful.) which guarantees abundance of stock during the period. Intensity of upwelling increases catchability and can result in a decline in spawning stock and recruitment. This can be one of the reasons for wide annual fluctuations in the catch of this resource

Some observations on the hatching and post-hatching behaviour of the cuttlefish Sepia pharaonis Ehrenberg

Egg capsules of the cuttlefish Sepia pharaonis were collected off Vizhinjam and the hatchlings studied in the laboratory. Most of the young ones hatch out within a period of eight days, and a few had premature batching. The hatched young ones resembling the adult externally were found to move by swimming, crawling or darting by jet propulsion. They settled on the bottom and were attracted towards light. The young ones were reared for a period of twenty three days in the laboratory

Stock assessment of mackerel in the Indian seas

Along both the coasts they start appearing in the catches when they are about two months old. But, along the west coast they are fiilly recruited to the fishery at an age of 6 months and along the east coast this happens at an age of 9 months. Bulk of the catches from west coast is by large seines of small meshes where young ones are liable to be caught and peak catches are from the size group of 140-149 mm. The major gear along the east coast is gill net with larger mesh and peak catches are from size group 190-199 mm. Along the west coast the estimated annual total mortality is 3.6. With an estimated M of 2.64 the fishing mortality F is 0.96 at an exploitation rate of 0.27 and E _^ estimated is 0.70

Non-Commutative Quantum Mechanics

A general non-commutative quantum mechanical system in a central potential $V=V(r)$ in two dimensions is considered. The spectrum is bounded from below and for large values of the anticommutative parameter $\theta$, we find an explicit expression for the eigenvalues. In fact, any quantum mechanical system with these characteristics is equivalent to a commutative one in such a way that the interaction $V(r)$ is replaced by $V = V ({\hat H}_{HO}, {\hat L}_z)$, where ${\hat H}_{HO}$ is the hamiltonian of the two-dimensional harmonic oscillator and ${\hat L}_z$ is z- component of the angular momentum. For other finite values of $\theta$ the model can be solved by using perturbation theory.Comment: Minors corrections and some references removed. To appear in PR

Testing spatial noncommutativiy via the Aharonov-Bohm effect

The possibility of detecting noncommutative space relics is analyzed using the Aharonov-Bohm effect. We show that, if space is noncommutative, the holonomy receives non-trivial kinematical corrections that will produce a diffraction pattern even when the magnetic flux is quantized. The scattering problem is also formulated, and the differential cross section is calculated. Our results can be extrapolated to high energy physics and the bound $\theta \sim [ 10 {TeV}]^{-2}$ is found. If this bound holds, then noncommutative effects could be explored in scattering experiments measuring differential cross sections for small angles. The bound state Aharonov- Bohm effect is also discussed.Comment: 16 pp, Revtex 4, 2 fig, new references added. To appear in PR