614 research outputs found

    The Bombay-Duck

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    The Bombay-duck, popularly known as "Bombil" is of great economic importance to the fishermen of the west coast of India, north of Ratnagiri. It is supported by a single species Harpodon neherpua (Hamilton). It has a wide and discontinuous distribution along to the coasts of East Africa, Indian subcontinent, Malaya, Indonesia and China. In India it is taken in large quantities on the south and south east coasts of Saurashtra on the Gujarat coast and the Konkan coast of Maharashtra. It is also taken in appreciable quantities on the Andhra-Orissa coast and from the estuaries of Bengal. With the introduction of a programme of mechanisation of the fishing craft under the Five Year Plans, the fishing activity and the area of exploitation along the Maharashtra and Gujarat coasts have considerably increased, resulting in larger landings of Bombay-duck. The fishery today has attained the status of one of the major fisheries of India

    Role of brackishwater prawn culture in the fisheries development of India

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    The seventh plan envisages an export target of Rs. 1000 crores from the fisheries sector. For Attaining this target the emphasis appears to be on exploitation from fishing grounds away from the Conventional/traditional grounds beyond the 30 fm line. These fishing ground can be fished only by Bigger trawlers, purse seiners and shrimpers which have the facility to remain at sea for a fortnight or More. Our experience has shown that the shrimp component from offshore grounds is negligible, less Than &%. Shrimp is the major component of our marine exports and if we have to achieve the targets Laid down the shrimp catch has to be enhanced in a big way

    A preliminary study of the pelagic fish eggs and larvae of the Gulf of Mannar and the Palk Bay

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    A study of the occurrence, distribution and development of fish eggs and larvae as an integral part of a fishery research programme serves as a valuable aid in the proper management of fisheries. Although there are several practical difficulties in studies of this nature, some progress has been made in this direction during the last few years in India. Devanesan and John (1940, 1941) have reported the occurrence of the eggs of Rastrelliger kanagurta and Kowala thoracata oflf the West Hill coast. Devanesan and Chidambaram (1941) gave a brief account of the eggs and newly hatched larvae of Anodontostoma chacunda and Caranx crUmenophthalmus. A few eel eggs from the Madras coast have been recorded by Aiyar et td. (1944тАФabstract). In a tabular statement Chacko (1950) gave the salient feature of the eggs and larvae of 16 species of fishes collected from the waters around the Krusadai Island, based on the observations of Delsman (1925-38). It has been, however, noticed that there are some variations in the descriptions given by Chacko and by Delsman. Nair and Bhimachar (1950) described three forms of eel eggs from the Gulf of Mannar. An account of the eggs and larvae of Sardinella sirm, Anchoviella tri, Thrissocles sp. and Solea ovata was given by John (1951). Descriptions of the eggs and larvae of the genera Thrissocles, Anchoviella, Cynoglossus, Caranx, Saurida and a pelagic egg mass from the Madras plankton were given by Nair (1952). The present paper deals with the pelagic fish eggs and larvae occurring in the Grulf of Mannar and the Palk Bay off Mandapam

    Experimental and numerical evaluation of single phase adiabatic flows in plain and enhanced microchannels

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    Thermal Dissipation is a critical issue in the performance of semiconductor devices. The current practice is to use forced convection by air over a heat sink which is bonded to the microelectronic device. With increased packing density of the circuits inside a chip, large amounts of heat is generated and air cooling is no longer sufficient. Forced liquid convection using microchannels is considered to be a viable option for cooling of these microprocessor chips. This work deals with the evaluation of the single phase pressure drop in microchannels. There are two types of microchannels under consideration. Plain microchannels which have basically long uninterrupted flow channels while the enhanced channels which have the interrupted flow lengths. Enhanced microchannels, because of their offset strip fin geometry, significantly increase both the heat transfer as well as the pressure drop. This work deals with the evaluation of single phase flow pressure drop in both plain and enhanced microchannels. For plain microchannels there have been a few investigations in the literature which suggest that the microchannel performance can generally be predicted using the classical fluid flow equations. However there are some experiments that still show departure from the classical theory that cannot be explained. It is proposed in this work that the reason for this discrepancy can be traced to the effects due to flow maldistribution in plain microchannels. A systematic experimental investigation is performed to study the effects of slight variations in channel dimensions and their influence on the flow maldistribution in an attempt to validate the applicability of classical theory to microchannel flows. Enhanced microchannels however have not been investigated thoroughly. There is very few data available in the literature. FLUENT is a CFD software which can be used as a tool to design and optimize these enhanced channels. However it has to be first validated with experiments. Thus pressure drop experiments are carried out on an offset strip fin silicon microchannel and the data is predicted using FLUENT, which is CFD software. Also existing predictive models for friction factor in offset strip fin minichannels are tested to check their validity for microchannel flows. For plain microchannels, it seen that with uniform flow assumption, the friction factor is either underpredicted or overpredicted using the theory depending upon the reference channel dimension. However by accounting flow maldistribution in plain microchannels, friction factor can be accurately determined using theoretical equations. For enhanced microchannels it is observed that FLUENT can predict the pressure drop within 10%. In this work only adiabatic flows are considered. It is recommended that this work should be extended to flows with heat transfer

    Some developmental stages of Caranx kalla Cuv. & Val.

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    These fish, when disturbed, were found to take shelter under the bell of the medusae. Judging from their movements, however, it may be mentioned that they seem to be cautious while moving about inside the bell, probably to avoid the stinging cells of the medusae. It is weIl-known that several species of carangids gather around floating objects such as, pieces of wood, coconut shell, medusae, etc_ and the principle of lure-line fishing is basea on this peculiar habit of carangids

    Observations on the biology of Harpodon nehereus (Hamilton)

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    The total catch of Bombay duck in Inaia during 1949 was estimated as about- 7250 tons ie about 2% of the total yield of marine fishes of India. The fishing season commences, some time in Septembeer just after the South West monsoon and continues for a period of about 4 to 5 months. It is also available during the other months of the year in smaller numbers but is somewhat rare during May to August

    Retrieval of displaced dental implant in maxillary sinus by modified Caldwell Luc technique

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    Displacement of dental implants into the maxillary sinus is an uncommon complication during implant placement. Here we present a case report of retrieval of dental implant displaced in the maxillary sinus with modification of Caldwell-Luc technique. A 35-year-old man presented to our institution for replacement of the maxillary right first molar using dental implant. At the point of final tightening of the implant, it suddenly got displaced into the maxillary sinus. The displaced dental implant was retrieved by performing a modification of the Caldwell-Luc technique which utilises gravitational force, saline as a vehicle and a tight-fitting suction tip in the surgically created lateral window. He was also instructed in coughing and sneezing techniques. Medical and dental professionals can utilise this technique effectively when advanced equipment such as endoscopes are not available to retrieve dental implants displaced in the maxillary sinus and it also preserves significant amount of alveolar bone in comparison to the traditional Caldwell Luc techniqu

    The Inhibition of Arginase by Proline in Cell-free Extracts of Mouse Mammary Tumour

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    Arginase activity was found to be increased in precancerous nodules and mammary tumour when compared with the mammary gland. Proline inhibited the mammary tumour arginase and up to 30 mmo1 concentration the inhibition follows first order kinetics. Hill analysis of the inhibition of arginase by proline showed that proline inhibits the arginase activity by competing directly at the active site without conformational change. The inhibition may be of regulatory importanec, involving a feedback mechenism in mammary tumours

    Bombay Duck, Harpodon nehereus (Ham.)

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    я╗┐The principal aim of any comprehensive fisheries research programme is primarily to obtain a maximum sustained yield and avoid depletion of stocks. Researches on the biology of the species contributing to a fishery form an essential prerequisite in regulating the exploitation of stocks to the maximum advantage. The study of distribution of the species and the stocks from which the fishery is supported forms valuable information in assessing the fishery potential. Considerable amount of information on these lines in respect of the commercially important fish species has been gathered by the Central Marine Fisheries Research Institute in the past two decades
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