491 research outputs found

    Utilization of trawl bycatch in Gujarat (India)

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    Bycatch from trawlers forms a signifi cant quantity of the total marine fi sh landings along the northwest coast of India, particularly in the state of Gujarat, which contributes about 23 percent of the total marine fi sh landings in the country. This paper discusses the composition of this bycatch, its signifi cance in terms of nutritional value, its present utilization pattern and the scope for improvement

    Coral reef ecosystem - Monitoring and assessment using satellite data sets

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    Remaining in splendid isolation, the Andaman and Nicobar Islands have a great relevance in the study of marine ecosystems. The islands, though remotely located in an ostensibly pristine environment have born witness to serious issues with regard to their ecosystem health. There are significant changes in the temperature and rain fall pattern in the islands and predictive modelling has forecasted further damage in the near future. The inundation of saline water into inland terrestrial ecosystems has created salinity stress to freshwater species while reducing the water available for domestic consumption. Terrestrial flora and fauna are vulnerable to the intruding saline waters. The marine ecosystem also faces grave challenges. There are issues of anthropogenic pollution resulting in damage of corals, regime shifts in community structure, water quality deterioration and other damage to marine fauna

    Kinetics of Decomposition of Nitramine Propellant by Differential Scanning Calorimetry

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    The paper describes an experimental procedure for the determination of overall kinetic parameters for the exothermic decomposition reaction of nitramine propellant. The kinetic parameters can be obtained through the use of differential thermal analysis (DTA), differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) methods. The procedure is applicable to reactions whose behaviour can be described by the Arrhenius equation and the general rate law. In the present work, DSC technique has been used for the evaluation of Arrehenius activation parameters and specific rate constants for thermal decomposition of a typical nitramine propellant. The kinetic parameters were computed by Ozawa and Kissinger methods for comparison. The activation energy value obtained from the Ozawa method is refined by an iteration procedure using Doyle approximation for the Arrhenius temperature integral p(x)

    A multi-wavelength study of star formation activity in the S235 complex

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    We have carried out an extensive multi-wavelength study to investigate the star formation process in the S235 complex. The S235 complex has a sphere-like shell appearance at wavelengths longer than 2 ╬╝\mum and harbors an O9.5V type star approximately at its center. Near-infrared extinction map traces eight subregions (having AV_{V} >> 8 mag), and five of them appear to be distributed in an almost regularly spaced manner along the sphere-like shell surrounding the ionized emission. This picture is also supported by the integrated 12^{12}CO and 13^{13}CO intensity maps and by Bolocam 1.1 mm continuum emission. The position-velocity analysis of CO reveals an almost semi-ring like structure, suggesting an expanding H\,{\sc ii} region. We find that the Bolocam clump masses increase as we move away from the location of the ionizing star. This correlation is seen only for those clumps which are distributed near the edges of the shell. Photometric analysis reveals 435 young stellar objects (YSOs), 59\% of which are found in clusters. Six subregions (including five located near the edges of the shell) are very well correlated with the dust clumps, CO gas, and YSOs. The average values of Mach numbers derived using NH3_{3} data for three (East~1, East~2, and Central~E) out of these six subregions are 2.9, 2.3, and 2.9, indicating these subregions are supersonic. The molecular outflows are detected in these three subregions, further confirming the on-going star formation activity. Together, all these results are interpreted as observational evidence of positive feedback of a massive star.Comment: 28 pages, 15 figures, 3 tables, Accepted for publication in The Astrophysical Journa

    Introduction to climate change

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    Introduction to climate chang

    TIRSPEC : TIFR Near Infrared Spectrometer and Imager

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    We describe the TIFR Near Infrared Spectrometer and Imager (TIRSPEC) designed and built in collaboration with M/s. Mauna Kea Infrared LLC, Hawaii, USA, now in operation on the side port of the 2-m Himalayan Chandra Telescope (HCT), Hanle (Ladakh), India at an altitude of 4500 meters above mean sea level. The TIRSPEC provides for various modes of operation which include photometry with broad and narrow band filters, spectrometry in single order mode with long slits of 300" length and different widths, with order sorter filters in the Y, J, H and K bands and a grism as the dispersing element as well as a cross dispersed mode to give a coverage of 1.0 to 2.5 microns at a resolving power R of ~1200. The TIRSPEC uses a Teledyne 1024 x 1024 pixel Hawaii-1 PACE array detector with a cutoff wavelength of 2.5 microns and on HCT, provides a field of view of 307" x 307" with a plate scale of 0.3"/pixel. The TIRSPEC was successfully commissioned in June 2013 and the subsequent characterization and astronomical observations are presented here. The TIRSPEC has been made available to the worldwide astronomical community for science observations from May 2014.Comment: 20 pages, 21 figures, 2 tables. Accepted for publication in Journal of Astronomical Instrumentatio

    Marine climate and fisheries scenario of Kerala Climcard-3

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    Marine climate and fisheries scenario of Kerala Climcard-

    Adaptations to Climate Change Impacts on Coastal Fisheries and Aquaculture

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    Adaptations to Climate Change Impacts on Coastal Fisheries and Aquacultur
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