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241.
Sunil Kumar Tripathy Dipanjali Behera Tushar Ranjan Routray 《Astrophysics and Space Science》2010,325(1):93-97
Spatially homogeneous and anisotropic LRS Bianchi type-I string cosmological models are studied in the frame work of general
relativity when the source for the energy momentum tensor is a bulk viscous fluid containing one dimensional strings. A barotropic
equation of state for the pressure and density is assumed to get determinate solutions of the field equations. The bulk viscous
pressure is assumed to be proportional to the energy density. The physical and kinematical properties of the models are discussed.
The role of bulk viscosity in getting an inflationary phase in the universe is studied. 相似文献
242.
M. Vijayakumaran R. Venkatesan T. Senthil Murugan T.S. Kumar Dilip Kumar Jha M.C. Remany 《新西兰海洋与淡水研究杂志》2013,47(2):623-634
Pueruli and post‐pueruli, early juveniles and sub‐adults of the spiny lobster, Panulirus homarus and juveniles of P. ornatus were grown in different floating sea cages along the southeast coast of India from May 2003 to May 2007. The first type of cage had a galvanised iron pipe frame (2.0 m × 2.0 m × 1.2 m) with steel woven mesh and four inner detachable compartments (0.75 m × 0.75 m × 1.10 m). Fibre‐reinforced plastic was used subsequently to fabricate cages (1 m × 1 m × 1 m). Pueruli and post‐pueruli of P. homarus (1.58 ± 0.62 g SD), stocked at 60 individuals/m2, grew to an average weight of 123.10 ± 26.22 g in 266 days with a survival rate of 70%. Sub‐adults of P. homarus with an average weight (± SD) of 123.61 ± 29.26 g reached 341.25 ± 46.22 g in 225 days at a stocking density of 21 individuals/m2 with a survival of 73 ± 6%. The post‐pueruli grew by 0.46 ± 0.10 g per day with a specific growth rate (SGR) of 1.64, whereas sub‐adults had a growth rate of 0.97 ± 0.20 g per day with a SGR of 0.43. At a higher stocking density of 80 individuals/m2, juveniles (51.83 ± 10.32 g and 58.20 ± 28.22 g) of P. homarus recorded growth rates of 0.86 ± 0.25 (SGR 0.82) and 0.97 ± 0.34 g (SGR 0.96) per day. This study indicates that post‐pueruli of P. homarus can be grown to over 200 g in 12 months and up to 350 g in 16 to 17 months in sea cages. Juveniles (average weight 76.35 ± 34.50 g) of P. ornatus, reared with P. homarus at a stocking density of 80 individuals/m2, recorded a weight gain of 139 g in 155 days at arate of 0.89 ± 0.32 g per day with an SGR of 0.67. Marine live clam, Donax spp., was the main feed supplemented with the gastropod, Xancus pyrum, the green mussel, Perna viridis, marine crab (Charibdis sp.), squid (Loligo sp.), and fish such as clupeids and Leognathus sp. Pueruli and post‐pueruli settled in large numbers (up to 35 individuals/month in one cage) both inside and outside the cages. 相似文献
243.
Twelve Recent benthic foraminiferal species hitherto not reported from the east and west coasts of India are presented and
illustrated. They are, namely- Bolivina semicostata, Elphidium subgranulosum, Hanzawaia nipponica, Planorbulina variabilis, Pseudononion japponicum, Reussella
haizumensis, Rosalina bradyi, Adelosina sp., Lagina sp. A, Lagina sp. B, Uvigerina sp. A and Uvigerina sp. B. 相似文献
244.
A highly diverse assemblage of mammal and other continental vertebrate fossils is reported in recent years from Vastan lignite
mine (21°25′47″ N; 73°07′30″ E). Its importance in testing palaeobiogeographic hypothesis of mammalian dispersal in to or
out of India has necessitated a definite age of the sequence. Nummulites burdigalensis is the only age diagnostic foraminifer in the section. This species is widespread in the Indian sedimentary basins and used
to mark Early Eocene strata. In the present study two subspecies of Nummulites burdigalensis, viz., Nummulites burdigalensis burdigalensis and Nummulites burdigalensis kuepperi, are distinguished which led to further biostratigraphic refinement. Their concurrence in the section implies basal Cuisian
age and shallow benthic zone SBZ 10 (most likely the lower part). The examination of this species from Kutch indicates the
occurrence of evolutionarily advanced subspecies Nummulites burdigalensis cantabricus of middle Cuisian age (SBZ 11). Contrary to some recent reports, the study rules out the occurrence of N. globulus or any other Ilerdian foraminifer from the mine section. 相似文献
245.
Identification of seismic events from continuously recorded seismic data in real-time through a Digital Seismic Data Recording
system is a difficult task. Despite the vast amount of research in this field, the signal processing and event parameters
discrimination algorithms have not yet fully come of age. Presently, we have a wide spectrum of trigger algorithms, ranging
from a very simple amplitude threshold type to the sophisticated ones based on pattern recognition approaches. Some of the
other approaches use adaptive technique and neural network methods. Researchers are continuously making efforts for the development
of algorithms using various techniques, which produce minimum false trigger. Some approaches have been reported which are
accurate for detecting first phase of events and take minimum possible computational time. In this paper several approaches
for detecting event signals in background noise are presented and their precision evaluation is discussed. 相似文献
246.
Shivani Shah B. M. Rao Prashant Kumar P. K. Pal 《Journal of Earth System Science》2010,119(6):775-781
Since the beginning of the summer monsoon 2009, experimental mesoscale weather forecasts in real time are being generated
using WRF model by the Meteorology and Oceanography Group at the Space Applications Centre (ISRO) and are disseminated through
MOSDAC () to various users. To begin with, the 12 h, 24 h and 48 h forecasts for the western India region are made available. A study
is undertaken to comprehensively assess the cloudiness prediction performance of WRF model. The evaluations have been made
over the three months period during monsoon 2009. INSAT cloud imagery data has been used as a reference for these evaluations.
The verification strategy includes computation of various skill scores. It is seen that probability of detection (POD) of
cloud is 84% and the false alarm rate (FAR) is around 18%. It is hoped that this assessment will provide information on the
use of these forecasts in various applications. 相似文献
247.
Distribution of arsenic and mercury in subtropical coastal beachrock,Gulf of Mannar,India 总被引:1,自引:0,他引:1
J Dajkumar Sahayam N Chandrasekar S Krishna Kumar G Victor Rajamanickam 《Journal of Earth System Science》2010,119(1):129-135
An assessment of coastal pollution was made on the basis of trace element concentrations (arsenic — As, mercury — Hg) in the
Gulf of Mannar. The beachrock samples were collected along the coastal tracts between Rameswaram and Kanyakumari. The samples
were dried and digested to determine the As and Hg using atomic absorption spectrophotometer (AAS-air-acetylene and nitrous
oxide method). The As and Hg accumulation status of the beachrock was assessed using geo-accumulation index values (I
geo). The accumulation of As and Hg in the beachrock ranges from 2.75 to 20.72 μg g−1 and from 0.06 to 0.31 μg g−1, respectively. The As and Hg concentrations in the beachrocks are compared with crustal average values and average of other
region sediments. The possible source of the contamination is from atmospheric deposition and anthropogenic activities. 相似文献
248.
Variations in long term wind speed during different decades in Arabian Sea and Bay of Bengal 总被引:1,自引:0,他引:1
A study has been carried out by comparing the extreme wind speeds estimated based on NCEP/NCAR reanalysis data for 100 years
return period using Fischer Tippet-1 (commonly known as Gumbel) and Weibull distributions for three locations (off Goa, Visakhapatnam
and Machilipatnam) in the north Indian Ocean. The wind dataset for Goa is compared with that from ERA-40 data. For higher
wind speeds (12–20m s−1), NCEP wind speed has higher percentage of occurrence than that of ERA-40. Analysis has shown slight upward trend in the
annual maximum wind for location off Machilipatnam with an increase of 1.2 cm s−1 per year and a decreasing trend of −1.3 cm s−1 per year in the case of Goa. The Weibull distribution with shape parameter 2 fits the annual maximum wind data better than
FT-1 distribution. 相似文献
249.
R. T. Ratheesh Kumar Tanmay K. Maji Rajesh R. Nair 《Journal of Earth System Science》2010,119(5):717-730
Indian Ocean subduction zone is one of the most active plate margins of the globe as evident from its vast record of great
magnitude earthquake and tsunami events. We use Bouguer admittance (Morlet isostatic response function) in Sumatra-Java subduction
zones comprising both the subduction and over-riding plates to determine the lithospheric mechanical strength variations.
We determine effective elastic thickness (T
e
) for five oceanic windows (size 990 × 990 km2) by analyzing the admittance using Bouguer gravity and bathymetry data. The results show bimodal T
e
values < 20 km for Sumatra and 20−40 km for Java. The lower bimodal values obtained for Sumatra appears to correlate well
with the zones of historical seismicity. This is in sharp contrast with Java subduction zone, which shows higher T
e
values (20–40 km) and apparently associated with low magnitude earthquakes. We suggest a strong and wide interseismic coupling
for Sumatra between the subducting and over-riding plates, and deeper mantle contributing to low strength, shallow focus —
high magnitude seismicity and vice versa for Java, leading to their seismogenic zonation. 相似文献
250.
Extreme climate and weather events are increasingly being recognized as key aspects of climate change. Pre-monsoon season
(March–May) is the hottest part of the year over almost the entire South Asian region, in which hot weather extremes including
heat waves are recurring natural hazards having serious societal impacts, particularly on human health. In the present paper,
recent trends in extreme temperature events for the pre-monsoon season have been studied using daily data on maximum and minimum
temperatures over a well-distributed network of 121 stations for the period 1970–2005. For this purpose, time series of extreme
temperature events have been constructed for India as a whole and seven homogeneous regions, viz., Western Himalaya (WH),
Northwest (NW), Northeast (NE), North Central (NC), East coast (EC), West coast (WC) and Interior Peninsula (IP). 相似文献