Histological Changes in a Few Tissues of Notopterus notopterus Induced by Sublethal and Lethal Concentrations of Pulp,Paper and Mixed Pulp and Paper Wastes     

S. R. Verma  S. G. R. Shukla  R. C. Dalela 《洁净——土壤、空气、水》1979,7(1):77-86

In the present work, histological changes in the gill, liver, kidney and intestine of Notopterus notopterus, induced by pulp waste, paper waste and mixed pulp and paper waste, have been studied both at sublethal and lethal concentrations. The pulp waste produces much more histological changes both at sublethal and lethal concentrations in the gill, liver, kidney and intestine as compared to paper waste and mixed pulp and paper waste. The changes are much more remarkable in the case of sublethal concentration, as compared to a lethal concentration. In a sublethal concentration, the localized necrosis, atrophy and partial and total liquefaction of epithelial cells, pilaster cells, mucous cells of the gill, hepatic cells of the liver, mesenchymatous cells, renal tubule cells and Bowman's capsule of the kidney, mucosal and submucosal cells and blood vessels of intestine have been observed. In lethal concentration, the changes are much more marked in the gill, as compared to the liver, kidney and intestine. The histological changes, produced in the different types of cells and in the tissue as a whole, can be correlated with the different chemical components present in the pulp waste, paper waste and mixed pulp and paper waste.  相似文献   

Ice accumulation rate in Changme-Khangpu glacier,Sikkim     

P. N. Shukla  N. Bhandari  V. N. Nijampurkar  D. Kameswara Rao  V. M. K. Puri  Sanjiv Sharma 《Journal of Earth System Science》1983,92(3):255-260

Vertical profiles of¹³⁷Cs and²¹⁰Pb have been determined in a 9 m column of ice from accumulation zone of Changme-Khangpu glacier in north Sikkim valley.¹³⁷Cs activity varies from 4 to 22 dpm/ L. In many samples²¹⁰Pb occurs at a level of 20 to 65 dpm/ L which is much higher than the expected fallout value.¹³⁷Cs and²¹⁰Pb activities correlate well with each other but not with the dust content. Possibility of²¹⁰Pb production in the nuclear explosions is discussed. Several peaks appear in the depth profile of¹³⁷Cs and²¹⁰Pb which can be matched with Chinese atmospheric nuclear explosions with some phase difference if a uniform ice accumulation rate of 0.7 m per year is assumed since 1969.  相似文献   

Parallel propagation effects on low-frequency Hall current instability in a dusty plasma     

M. Rosenberg  P.K. Shukla 《Planetary and Space Science》2002,50(3):261-267

  相似文献   

Jeans Instability in Collisional Dusty Plasmas     

P.K. Shukla  Frank Verheest 《Astrophysics and Space Science》1998,262(2):157-162

It is shown that dust-neutral and ion-neutral drags can produce instabilities of electrostatic waves in multicomponent self-gravitating dusty plasmas. Explicit expressions for the growth rates of the instabilities are presented. The relevance of our investigation to fragmentation of molecular dust clouds is discussed.  相似文献   

Waves and Instabilities in Magnetized Dusty Plasmas     

Padma K. Shukla 《Astrophysics and Space Science》1998,264(1-4):235-245

The status of waves and instabilities in magnetized dusty plasmas is summarized. The effects of an external magnetic field on low-frequency electrostatic and electromagnetic waves in dusty plasmas are discussed. The kinetic and hydrodynamic instabilities are shown to excite magnetized dusty plasma waves. The presence of the latter can give rise to an oscillatory wake-potential which can be responsible for the charged dust grain attraction. The relevance of our investigation to laboratory and space plasmas has been pointed out. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Nonlinear Drift-Alfvén Waves in Relativistically Hot Nonuniform Electron-Positron Plasmas     

O.G. Onishchenko  O.A. Pokhotelov  P.K. Shukla  L. Stenflo 《Astrophysics and Space Science》1998,262(3):249-262

The magnetic viscosity tensor is derived for a magnetized relativistic collisionless plasma with temperature gradients. By means of this tensor we deduce the nonlinear equations for drift–Alfvén waves in a relativistic electron-positron low plasma with density and temperature gradients. It is shown that our new equations have solutions in the form of dipolar vortices. The present results should be relevant to a number of astrophysical objects with strong electron-positron pair production, e.g. in pulsars as well as in accretion disks and jets.  相似文献   

Comments on the parametric excitation of low-frequency electrostatic waves     

L. Stenflo  P.K. Shukla 《Journal of Atmospheric and Solar》1997,59(18):2431-2433

The nonlinear excitation of low-frequency electrostatic waves by a high-power pump wave is re-examined. In that way, we present simple formulas that are relevant for ionospheric heating experiments.  相似文献   

Survivality and Impaired Growth in Arsenic Treated Fingerlings of Channa punctatus,a Fresh Water Murrel     

J. P. Shukla  K. N. Shukla  U. N. Dwivedi 《洁净——土壤、空气、水》1987,15(3):307-311

The LC₅₀-values of As³⁺-compounds for Channa punctatus are determined for a 48-h exposure to 19.4 (18.02… 21.3) mg/1 and for a 96-h exposure to 14.3 (13.06… 16.80) mg/1. At a long-time exposure to 7.0 mg/1 As³⁺, during the first seven days there does not occur any change of growth, then the growth in length and the increase in weight decreased by 6.6 and 11.7%, respectively, till the 31st day. At the same time, the RNA content of the muscle decreased by 11.5% to 966.7 μg/g fresh weight and the protein content decreased by 12.5 % to 95.39 mg/g fresh weight.  相似文献   

Deleterious effects of Malathion on survivality and growth of the fingerlings of Channa punctatus (BLOCH.), a freshwater murrel     

J. P. Shukla  M. Banerjee  K. Pandey 《洁净——土壤、空气、水》1987,15(6):653-657

The LC₅₀ of Malathion for Channu punctatus is determined for 24… 96 h of exposure as 10.95… 3.22 mg/l. At exposure to 2.5 mg./l Malathion, growth–measured by increase in weight–is significantly reduced from the 19th day and reduced by 10 % till the 31st day. During the same period of time, the RNA and protein contents of the muscle is lowered by 10 and 15 %, respectively, as compared with the control. In addition to an acute toxic effect, in sublethal concentrations Malathion has also pronounced effects on growth and metabolism.  相似文献   

An evaluation of the CIC model of210Pb dating of sediments     

B. S. Shukla  S. R. Joshi 《Environmental Geology》1989,14(1):73-76

Both linear and polynomial regression analysis techniques are used to assess the CIC (constant initial concentration) model of²¹⁰Pb dating. Results obtained using published²¹⁰Pb and porosity profiles in 12 freshwater sediment cores show that linear regression affords more reliable results. The polynomial regression, while capable of predicting the values of the constant or derived from porosity data, gives reasonable results only when all the coefficients of the polynomial are of appropriate sign. Lower values for all the parameters are obtained in all cases if the effect of compaction is not considered.  相似文献