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排序方式: 共有46条查询结果,搜索用时 31 毫秒
21.
DHANEESH Kottila Veettil AJITH KUMAR Thipramalai Thankappan SWAGAT Ghosh BALASUBRAMANIAN Thangavel 《中国海洋湖沼学报》2012,30(4):528-534
Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which the impacts of feed type, water temperature, and light intensity, on the efficiency of its reproduction, were revealed. The fish were accommodated along with sea anemones in fibre glass tanks to determine the influence of brooder diet on breeding efficiency. Higher reproductive efficiency [number of eggs laid (276 22.3 eggs)] was observed when fish were fed live Acetes sp. rather than clam (204 16.4 eggs), trash fish (155 12 eggs) and formulated feed (110 10 eggs). The spawning rate was increased during September and October (water temperature, 28.74 0.55°C) on average of 2.4 spawning per month; and low spawning rate was in January (water temperature, 24.55 0.45°C) on average of 1 spawning per month. Among three light intensities (100, 500, and 900 lx) set to evaluate larval survival rate, larvae showed the highest survival rate (65.5%) at 900 lx. The breeding method specifically in brackishwater developed in the present study is a new approach, will help the people from the regions of estuary and backwater to enhance their livelihood and it will lead to reduce the exploitation from the wild habitat. 相似文献
22.
We have measured the decorrelation frequency (f
v
) and decorrelation time (t
v
) for 15 pulsars. We show by combining our data with those of others thatfv∫ DM-1.79±0.14 andt
v
∫ DM-0.80±0.15 up to a dispersion measure (DM) of about 60 cm3 pc. The combined data set does not form a complete sample, but the relations obtained from our measurements on 14 pulsars,
which form almost a complete sample up to 41 cm3 pc, are consistent with the above relations, suggesting that these relations are not seriously affected by selection effects.
The relations are broadly in agreement with those expected from a homogeneous interstellar medium and are in disagreement
with earlier conclusions by others that these relations steepen even for low-DM pulsars. The agreement suggests that the local
interstellar medium is homogeneous at least up to a distance of about 2 kpc. 相似文献
23.
A solar radio type II burst (which was seen as two patches of emission, one during 07:00–07:13 UT and other one during 07:20–07:35 UT)
was observed on 22 March 1998 using the Madurai radio spectrograph. A broad range of data (from Culgoora and Hiraiso spectrographs,
white-light data from SOHO/LASCO and X-ray data from Yohkoh and GOES satellites) was also studied for this event, which was analyzed in comparison with these supplementary data. In
addition, the conditions associated with this shock were analyzed quantitatively. From the above investigations, the following
conclusions have been made. The temporal relationship between H-alpha flare and burst has shown that the active region AR 8185
is the source of this type II burst. A bright front feature observed with LASCO is also associated with this type II burst
and active region AR 8185. The time profile of the shock derived from the first patch of this type II burst coincides with
the flare starting time. Also, within error limits, the start time of the CME is same as the flare. Hence, it is not possible
to decide whether the type II originated in the flare or was driven by CME. In addition, the investigations of the second
patch alone has provided the following results. The inferred shock speed for the second patch of emission is lower than the
first and closer to the CME speed. The emission occurred below 50 MHz. These conditions imply that this patch may be a separate
burst which might have been produced by the CME alone. 相似文献
24.
The present study aimed at characterizing the heavy metal resistance and assessing the resistance pattern to multiple heavy metals (300 mmol L?1) by Palk Bay sediment bacteria. From 46 isolates, 24 isolates showed resistance to more than eight heavy metals. Among the 24 isolates S8-06 (Bacillus arsenicus), S8-10 (Bacillus pumilus), S8-14 (B. arsenicus), S6-01 (Bacillus indicus), S6-04 (Bacillus clausii), SS-06 (Planococcus maritimus) and SS-08 (Staphylococcus pasteuri) exhibited high resistance against arsenic, mercury, cobalt, cadmium, lead and selenium. Plasmid curing confirmed that the heavy metal resistance in S8-10 is chromosomal borne. Upon treatment with the heavy metals, the strain S8-10 showed many morphological and physiological changes as shown by SEM, FTIR and AAS analysis. S8-10 removed 47% of cadmium and 96% of lead from the growth medium. The study suggests that sediment bacteria can be biological indicators of heavy metal contamination. 相似文献
25.
In the present work, experiments have been carried out with a focus to reduce the volume requirement of solvent by mixing with imidazolium based ionic liquids (ILs) for the solvent extraction of phenol, p‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, and pentachlorophenol from aqueous solutions. The effect of aqueous phase pH (2–12), agitation speed (100–450 rpm), solute concentration in feed (2–50 mg/L), temperature (303–333 K), treat ratio (1–11), and 1‐butyl‐3‐methyl imidazolium tetrafluoroborate [Bmim]+[BF4]? volume in tributyl phosphate (TBP; 0–0.7% v/v) on extraction of phenols has been studied and optimized. Parameters like strip phase pH (3–13) and stripping agent concentration (0.001–0.009 N) have also been studied for stripping of phenols from solvent phase. It has been found that 0.5% v/v of ionic liquid [Bmim]+[BF4]? in solvent TBP extracts more than 97.5% of phenol and chlorophenols from aqueous solutions with a treat ratio (aqueous to solvent phase ratio) of 5. Transport mechanism for extraction and stripping of phenol and chlorophenols using ionic liquid [Bmim]+[BF4]? has been discussed. The results show that by appropriate selection of extraction and stripping conditions, it is possible to remove nearly all phenols with a treat ratio of 5. 相似文献
26.
Ramar Vinoth Mohan Gopi Thipramalai Thankappanpillai Ajith Kumar Thirunavukarassu Thangaradjou Thangavel Balasubramanian 《中国海洋大学学报(英文版)》2012,11(1):105-110
A survey on coral bleaching was carried out at Agatti Island of Lakshadweep from May to June 2010.Elevated sea surface temperatures(SSTs)of the region exceeded the seasonal average and delayed the onset of monsoon,which triggered widespread bleaching of corals.The Agatti reefs showed an average of 73%bleached corals with apparent bleaching-related mortality of sea anemones(87%)and giant clams(83%).The SST increased up to 34℃with an average maximum SST of 32.5℃ during the study period between May and June 2010.Coral reefs on the southern side of the island are fully or partially exposed to sun light during low tide in contrast to the other side.This suggests that the mortality is more likely due to the low tide exposure than exclusively due to the elevated SST.Observations indicated a clear increase in coral bleaching during April 2010,at levels higher than that in normal summer. 相似文献
27.
Balasubramanian Balamuralikrishnan Vellingiri Balachandar Mohana Devi Subramaniam Karthick Kumar Alagumuthu Shanmugam Sureshkumar Meyyazhagan Arun Sundaramoorthy Arun Krishnan Padmavathi Abdul Hakkim Razeena Mohan Gomathi Palanivel Velmurugan Shahnaz N. Dharwadkar Keshavarao Sasikala 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(7):1801-1814
Chemicals, especially silica, have been suspected to cause genetic alterations in pottery industry workers. The present study aims to analyze the frequency of chromosomal aberrations (CA), micronucleus (MN) and DNA damage (comet assay) in the peripheral blood lymphocytes and the immunological alterations workers chronically exposed to silica and in control subjects. In our study, 50 silica exposed workers and 35 control subjects were recruited and silica level was measured by respirable dust and respirable quartz concentrations of badge dosimeter. The serum immunoglobulins (IgM, IgG, and IgA) of all the subjects were measured by using ELISA method. The individuals exposed to silica have a significant increase in the frequency of CA, MN and the total DNA damage (p < 0.05). Immunoglobulin elevation on silica exposed workers was statistically significant (p < 0.05) on comparison with their respective controls. Investigation of the smoking and alcohol habitats coupled with silica exposure in exposed and control subjects represents alcohol consumption and smoking as additional risk factors and must be avoided. Multiple linear regression analysis obtained for CA, MN and comet assay confirm these tests as biomarkers for silica exposed pottery workers. Some confounding factors also showed significant influence on exposed subjects. These results indicate the mutagenic risk in the working environment has a high probability of association with the silica dust exposure in pottery industries. Nevertheless, the present study will create awareness and public concern not only among the silica exposed workers but also to the welfare of their progeny. 相似文献
28.
Both aerosol and rainwater samples were collected and analyzed for ionic species at a coastal site in Southeast Asia over
a period of 9 months (January–September 2006) covering different monsoons. In general, the occurrence and distribution of
ionic species showed a distinct seasonal variation in response to changes in air mass origins. Real-time physical characterization
of aerosol particles during rain events showed changes in particle number distributions which were used to assess particle
removal processes associated with precipitation, or scavenging. The mean scavenging coefficients for particles in the range
10–500 nm and 500–10 μm were 7.0 × 10−5 ± 2.8 × 10−5 s−1 and 1.9 × 10−4 ± 1.6 × 10−5 s−1, respectively. A critical analysis of the scavenging coefficients obtained from this study suggested that the wet removal
of aerosol particles was greatly influenced by rain intensity, and was particle size-dependent as well. The scavenging ratios,
another parameter used to characterize particle removal processes by precipitation, for NH4
+, Cl−, SO4
2−, and NO3
− were found to be higher than those of Na+, K+, and Ca2+ of oceanic and crustal origins. This enrichment implied that gaseous species NH3, HCl, and HNO3 could also be washed out readily. These additional sources of ions in precipitation presumably counter-balanced the dilution
effect caused by high total precipitation volume in the marine and tropical area. 相似文献
29.
Samikkannu Muthuvelu Perumal Murugesan Muniyandi Muniasamy Shanmugam Vijayalakshmi Thangavel Balasubramanian 《Ocean Science Journal》2013,48(2):183-195
Variations in benthic biodiversity owing to bottom trawling were studied in the inshore waters of Parangipettai (Lat.11°24′N; Long. 79°464′E) and Cuddalore (Lat. 11°434′N; Long. 79°494′E), India from February 2009 to January 2010. Four stations each in Parangipettai and Cuddalore were prepared and established. A total of 114 species in Parangipettai and 101 in Cuddalore were found. The population density showed a maximum (10,387 no. m-2) in Parangipettai in the sample collected before trawling and a minimum (40no. m?2) in Cuddalore in the samples collected after trawling. Among the faunal groups, polychaetes topped the list followed by other groups of organisms both in the samples before and after trawling. Shannon diversity varied from 2.23 to 4.24, 1.85 to 3.45; Margalef richness from 3.2 to 5.9, 2.57 to 4.25; Pielou’s evenness varied from 0.79 to 0.94, 0.81 to 0.88 in the samples collected before and after trawling respectively in Parangipettai. In Cuddalore waters, Shannon diversity ranged from 2.15 to 3.85, 1.92 to 3.15; Margalef richness from 2.95 to 5.2, 2.24 to 3.95 and Pielou’s evenness index from 0.84 to 0.91, 0.79 to 0.82 in the samples before and after trawling respectively. Multivariate methods also showed distinct variations in terms of species composition and abundance between regions and samples. 相似文献
30.
Udo Noack Thomas Geffke Ramani Balasubramanian Jutta Papenbrock Mike Braune Dirk Scheerbaum 《洁净——土壤、空气、水》2003,31(6):482-490
The effects of the chloroacetanilide herbicide metazachlor have been investigated in outdoor artificial mesocosms. Decreasing phytoplankton densities were caused by the application, however, the communities recovered after 30 to 35 days. Periphyton growth was found to be affected not only by the herbicide application but by the presence of species with different ability to grow on artificial substrates. Zooplankton diversity was small due to low density of ingestible algae species. Oxygen saturation was found to be correlated with the dosage levels of the herbicide in the second half of the study. 相似文献