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The physical state of a moderately dense, uniform, pure hydrogen medium, pervading the metagalaxy and partaking in the general cosmic expansion, is considered. The cosmic X-ray photon spectrum, which is now observed down to about 0.25 keV, together with various plausible extrapolations down to the Lyman limit, is invoked as the source of ionization and heating of this medium. Isothermal and adiabatic modes of expansion of the intergalactic medium are studied as limiting cases of the present mode of expansion. The isothermal mode generates highly ionized but lukewarm (7700 KT25000 K) models of the medium, with the, so far unknown, turnover point in the cosmic X-ray spectrum as the parameter required to fix the temperature and degree of ionization uniquely, for any assumed value of the present density. The adiabatic mode, while giving rise to high degrees of ionization, also produces significantly higher temperatures which are independent of density and always greater than about 28000 K. In conclusion, a possible explanation for the anomalous 3C 9 result is adduced. 相似文献
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Dr. Thomas Mathai K. N. Rajarama Satish Kumar M. Suresh Chandran M. R. Asoka Kumar 《Marine Georesources & Geotechnology》2013,31(2):180-193
Offshore geotechnical surveys form part of an integrated investigation to rejuvenate a decrepit minor port at Badagara, Kerala on the southwestern coast of India. The sediments typify a fluvio-marine milieu ranging from silty clay, sand, silty sand, sandy silt and clayey silt. Geotechnical and sedimentological studies of shallow cores reveal the geotechnical aspects besides the depositional history of the sediments. Downcore geotechnical variations and regressive coefficients based on their inter-relationships highlight diverse factorial inferences. X-Ray Diffraction data indicate the prominent clay type. A comparative evaluation of the geotechnical characteristics of clayey sediments off Badagara, with similar studies along various sectors of the Kerala coast, both on land as well as in the near shore, is broadly attempted. Geotechnical studies carried out earlier on the uplifted Cochin marine clays provide comparative data for evaluating the possible variations between present day marine clayey sediments occurring along the Kerala coast and uplifted marine clays which, besides their gross variations in levels with respect to the present sea-level, also obviously relate to a much older depositional environment and provenance during probable Holocene times. 相似文献
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Baseline data for hepatic xenobiotic metabolizing biomarker enzyme activities were obtained for artificially reared tilapia Oreochromis niloticus, and were compared with those of the plaice (Pleuronectes platessa) and rainbow trout (Onchorynchus mykiss). Basal activities exhibited species variations with notably higher CYP1A and phenol UGT activities and lower GST activity in plaice than the freshwater species. Interspecies relationships between gene families determined by immunoblotting and substrate-activity profiles demonstrated the presence of homologous CYP1A and CYP3A enzymes in all three species, alpha class GSTs in plaice and trout, mu and pi class GSTs in trout and theta class GSTs in plaice and tilapia. CYP1A of tilapia was induced by 3-MC or PBO treatment, whilst CYP3A was induced by PCN treatment. 相似文献
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Thomas Mathai M. Suresh Chandran S. B. Nair M. R. Asoka Kumar Satish Kumar P. Praveen Kumar K. N. Rajarama T. Stephen George 《Marine Georesources & Geotechnology》2007,25(3):151-165
Sediment core samples collected during geotechnical surveys along the West Coast of India in the near shore areas of Arabian Sea have generated data on the geotechnical index properties of clayey sediments up to nearly 5 m depth below seafloor. A comparative study of three sectors within themselves is attempted before carrying out a final evaluation between the sectors. Cohesive clayey sediments of Gujarat sector are comparable though widely variant in a few aspects; in the Maharashtra-Goa-Karnataka sector though, plasticity levels and clay type vary, and activity and consistency levels are quite similar. Though broadly comparable, the clayey sediments of Kerala-Tamilnadu sector have quite diverse characteristics that fail to conform to any particular pattern as each area has an exclusive set of geotechnical properties. 相似文献
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Thomas Mathai M. Suresh Chandran S. B. Nair M. R. Asoka Kumar Satish Kumar P. Praveen Kumar 《Marine Georesources & Geotechnology》2013,31(3-4):151-165
Sediment core samples collected during geotechnical surveys along the West Coast of India in the near shore areas of Arabian Sea have generated data on the geotechnical index properties of clayey sediments up to nearly 5 m depth below seafloor. A comparative study of three sectors within themselves is attempted before carrying out a final evaluation between the sectors. Cohesive clayey sediments of Gujarat sector are comparable though widely variant in a few aspects; in the Maharashtra-Goa-Karnataka sector though, plasticity levels and clay type vary, and activity and consistency levels are quite similar. Though broadly comparable, the clayey sediments of Kerala-Tamilnadu sector have quite diverse characteristics that fail to conform to any particular pattern as each area has an exclusive set of geotechnical properties. 相似文献
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