Crystal cored optical waveguides

Imperial Users onl

Turbo and Trochus resources

Among the commercially important molluscs in the Andaman and Nicobar Islands, Trochus nilotkuS Linn6 and Turbo marmoratm Linne occupy a prominent position because of their abtmdance and economic value. Commercial exploitation of these shells may be deemed to have started from 1929 (Panikkar, 1938) although, even earlier to this, Japanese fishermen from Singapore had been fishing for them around these islands unauthorisedly (Rao, 1939). Of these two species, Trochus niloticus was foimd to be more abundant in all the islands surveyed. Though there were good landings of these shells in the earlier years, they started declining in later years, which prompted the Andaman Administration to appoint a Special Officer to carry out scientific studies on the fishery. A consolidated report on the shell fishery of these islands during 1930-35 was published by Rao (1939). Amirthalingam (1932), Setna (1933), Prashad and Rao (1933,1934), Rao (1936 a, b, 1937, 1941) and Panikkar (1938) made more detailed observations on the shell fishery of the Anda- mans, with accoimts of the feeding habits, breeding seasons, size at sexual maturity, growth rate and other biological details of T. niloticus. Anon (1939) has briefly reviewed the results of the investigations made by the Zoological Survey of India in Andamans. Menon (1976), Cbatterjee (1976) and Appufcuttan (1977) have described the importance of Trochus and Turbo in the shell-craft industry. The Trochus and Turbo resources of the different islands were surveyed during 1978 by the Central Marine Fisheries Research Institute, the results of which, along with notes on the fishery, are presented here

Present status of molluscan fisheries and culture in India

India has extensive molluscan resources along both the coasts, in the numerous islands, bays, back waters and estuaries and also in the seas around the Sub-continent

Processing, preservation and marketing

Shellfishes are highly perishable and this irrespectiye of their market potential is a major hurdle to the development of the industry. Soon after spawning the meat will be thin and not very tast

On the Gammaridean amphipoda of the Gulf of Mannar, with special reference to those of the pearl and chank beds

During the underwater survey of the pearl and chank beds off Tuticorin carried out by 'Scuba' diving, a number of amphipods were also seen amongst various material collected from the sea bottom. These amphipods were studied in detail. incorporating the amphipods of the pearl banks of Ceylon described by Walker (1904) a complete list with synonymies of all the reported species of amphipods from the Gulf of Mannar, together with the description and sketches of species wherever found necessary, has been given in this account

Technology of edible oyster culture

In oyster culture there are two important major aspects (1) production of seed and (2) growing the seeds to marketable size.This paper deals with the latter aspect of oyster culture

Studies on the growth of the wedge clam, Donax (Latona) cuneatus Linnaeus

Of the several species of wedge clams of the family Donacidce that occur on the east and west coasts of India in the surf-beaten sands, Donax scortum to some and Donax cuneatus to a very large extent are valued as food by many people. In the Palk Bay, ail along the beach from Pillaimadam shore <Long. 79° 5' and Lat. 9° 17') to Attankarai (Long. 79° 0' and Lat. 9° 21'), a distance of about seven miles, the receding tides reveal Donax cuneatus in abundance. It forms the food of a large number of fishermen along the coast when the sea is rough and the general fishery conditions poor. It is usually fished only during such off-seasons and is not sold in the open, market. The clam meat is cooked whole or made into a paste and treated with condiments in the preparation of curries. Dead shells of these clams, washed ashore, are collected by the womenfolk for preparing lime. However, at present there is no regular fishery of these clams for food or any organised lime burning industry, with the result that this valuable resource is wasted without being much utilized. The present investigation was taken up with a view to exploring the possibilities of exploitation of this resource of food without any undue damage to the beds

Hemolymph proteins and reproduction in Periplaneta americana: the nature of conjugated proteins and the effect of cardiac-allatectomy on protein metabolism

1. The nature and behavior of the conjugated proteins in the hemolymph of adult female Periplaneta americana (L.) have been studied in relation to the ovarian cycle, using disc electrophoresis in polyacrylamide gel and various staining procedures. It is shown that there may be not only a change in the relative concentration of the different protein fractions with oocyte growth, but also differences in their chemical composition. Fraction 3 and the female fraction 4, which represent the major proteins in the blood, appear to serve as carriers of lipids to the ovaries, besides most likely providing proteinaceous yolk precursors to the same. Fractionations made with ovarian homogenates seem to indicate that the lipids and sugars bound to such proteins may become freed at entry into the ovary. 2. Cardiac-allatectomy has been found to result in a pronounced accumulation of proteins in the blood, and also in changes in their chemical composition. In such animals there is a tendency with aging for the loss of lipid prosthetic groups and for several of the fractions including the major proteins to stain preferentially for carbohydrates. This effect could be reversed by the implantation of fresh cardiacum-allatum complexes taken from adult females. It is suggested that in cardiac-allatectomized females there is probably a bilateral arrest of lipid and protein metabolism, and that the vitellogenic proteins already synthesized. but not utilized by the ovary, become converted into glycoproteins. 3. Fractionation studies on fat body homogenates of females in different stages of ovarian activity appear to indicate that in Periplaneta americana none of the soluble lipo- or glycoproteins, including the female fraction, is as such synthesized or stored in the fat body

Computational Cameras: Approaches, Benefits and Limits

A computational camera uses a combination of optics and software to produce images that cannot be taken with traditional cameras. In the last decade, computational imaging has emerged as a vibrant field of research. A wide variety of computational cameras have been demonstrated - some designed to achieve new imaging functionalities and others to reduce the complexity of traditional imaging. In this article, we describe how computational cameras have evolved and present a taxonomy for the technical approaches they use. We explore the benefits and limits of computational imaging, and describe how it is related to the adjacent and overlapping fields of digital imaging, computational photography and computational image sensors