Showing papers by "Jawaharlal Nehru University published in 1995"
TL;DR: In this paper, the existence of pure strategy Nash equilibria in price competition in a homogeneous product market when costs are strictly convex is analyzed and it is shown that if output is demand determined such equilibrium always exists.
Abstract: The paper analyses the existence of pure strategy Nash equilibrium in price competition (or Bertrand equilibrium) in a homogeneous product market when costs are strictly convex and proves that if output is demand determined such equilibrium always exists. This paper also characterises such equilibria and shows that if firms are identical such equilibria are necessarily non-unique. However for firms with asymmetric costs it can be unique or non-unique.
228 citations
TL;DR: Changes in the activities of enzymes involved in the detoxification of reactive oxygen species in wheat seedlings in response to variations in the light environment were studied and suggest an adaptive response of the plants to higher amounts of active oxygen species generated at higher light intensities.
Abstract: Changes in the activities of enzymes involved in the detoxification of reactive oxygen species in wheat seedlings (Triticum aestivum L.) in response to variations in the light environment were studied. Activities of ascorbate peroxidase, superoxide dismutase, monodehydroascorbate reductase, dehydroascorbate reductase, glutalhione reductase and catalase were much lower in seedlings grown under low-light conditions than in those grown under high-light conditions. Activities of all these enzymes significantly increased within 24 h of transfer of the low-light-grown seedlings to the high-light regime. The results suggest that the increase in enzyme activities was an adaptive response of the plants to higher amounts of active oxygen species generated at higher light intensities. An accumulation of glutathione was also observed, which could also be a part of the defense strategy to meet the increased generation of active oxygen species upon transfer of low-light-grown plants to high-light conditions.
85 citations
TL;DR: In this article, the heavy metals' affinity for specific geochemical phases in the recently deposited sediments in the Chilka lake was investigated, where three samples were collected and analyzed using a sequential extraction scheme.
Abstract: Chilka lake, the largest coastal lagoon of Asia is one of the most dynamic ecosystems along the Indian coast. Historically the lagoon has undergone a considerable reduction in surface area due, in part, to input from natural processes but mostly due to human activities. The purpose of this investigation is to document the heavy metals' affinity for specific geochemical phases in the recently deposited sediments in the lagoon. Thirty-three samples were collected and analyzed for different geochemical phases of Fe, Mn, Cu, Cr, Ni, Pb, and Zn utilizing a sequential extraction scheme. In the nonlithogenous fraction, the exchangeable fraction was not geochemically significant, having <2% of the total metal concentration for all the elements. However, the carbonate fraction contained the following percentages of the total concentration: <1% Fe, 13% Mn, 6% Cu, 4% Cr, 8% Ni, 13% Pb, and 12% Zn, suggesting the detrital origin of the sediments. Reducible and organic matter-bound fractions were the significant phases in the nonlithogenous fraction, containing 9% Fe, 16% Mn, 15% Cu, 16% Cr, 16% Ni, 14% Pb, and 14% Zn in the former and 4% Fe, 3% Mn, 17% Cu, 3% Cr, 14% Ni, 15% Pb, and 14% Zn in the latter. The phenomenon has been attributed to the scavenging affinity of Fe-Mn oxides and affinity for sorption into organic matter of the lagoon sediments. The lithogenous, residual fraction generally considered as a guide for natural background values was determined to contain 87% Fe, 67% Mn, 61% Cu, 77% Cr, 61.3% Ni, 56% Pb, and 60% Zn of the total concentrations.
82 citations
TL;DR: In this article, it was shown that metaigneous gneisses that occur as slivers on the western margin of the schist belt have an isotopic character similar to that of the metaplutonic rocks on the same side of the Kolar Schist Belt.
Abstract: Conspicuous Nd, Sr and Pb isotopic differences exist between the Archean gneiss terranes adjoining the suture at the Kolar Schist Belt, south India. These gneisses, which are the deformed equivalents of plutonic and volcanic rocks, have known or inferred igneous ages of 2630 to 2530 Ma. Initial isotopic ratios of Nd, Sr and Pb suggest that metaplutonic gneisses west of the Kolar Schist Belt were emplaced into, and variably contaminated by, an evolved continental crust that formed prior to 3200 Ma. Felsic metaigneous gneisses that occur as slivers on the western margin of the schist belt have an isotopic character similar to that of the metaplutonic rocks on the same side of the Kolar Schist Belt. On the east side of the Kolar Schist Belt the isotopic evidence suggests that the 2530 Ma granitic gneisses were not derived from or contaminated by an older continental crust. Their source probably evolved with a Nd isotopic composition similar to that of typical Archean mantle, but became light rare earth element enriched after 2900 to 2700 Ma. The inferred tectonic setting for the west side of the Kolar Schist Belt is an Andean continental magmatic arc. For the east side of the Kolar Schist Belt, a possible Phanerozoic analog is an evolved island arc, such as Japan.
80 citations
TL;DR: Archean metabasaltic rocks from three separate blocks that constitute the north-south trending Ramagiri schist belt of the Eastern Dharwar Craton have large variations in ϵNd2750.
67 citations
TL;DR: In this article, the exact two-level correlation functions for the class of transitions which eventually go to the Gaussian unitary ensemble were derived and shown to be exactly solvable.
Abstract: The transition in spectral fluctuations in a quantum chaotic system as a good symmetry of the system is gradually broken is describable in terms of Dyson's Brownian-motion model. Here the magnitude of symmetry breaking plays the role of ‘time’ while the ‘temperature’ determines the universality class of random matrices to which the system goes in ‘equilibrium’. Recently we have shown that the transition itself has a universal classification and is useful in studying exact or weakly broken symmetries in complex many-body systems. In this paper we derive the exact two-level correlation functions for the class of transitions which eventually go to the Gaussian unitary ensemble. It appears that the transition to the Gaussian orthogonal and symplectic ensembles may also be exactly solvable.
63 citations
TL;DR: The results of this study suggest that rapid eye movement sleep deprivation induced increase in Na-K ATPase activity may be mediated by norepinephrine acting on either alpha-1 and/or alpha-2 receptors.
54 citations
TL;DR: It is demonstrated that pre-treatment with garlic extract can lead to significant dose-related reductions in the frequencies of gamma-radiation-induced micronucleated polychromatic erythrocytes and the anticlastogenic effect of garlic extract was observed against lower radiation doses.
Abstract: Garlic extract was evaluated in the mouse bone marrow micronucleus test for its possible protective effects against gamma-radiation-induced chromosomal damage. Together with this, biochemical assays were carried out to determine the changes in sulfhydryl content and glutathione S-transferase activities. Three doses of freshly prepared garlic extract (125, 250 and 500 mg/kg b.w.) were orally administered for 5 consecutive days, and the animals were irradiated 2 h after the final feeding. The results of the micronucleus test demonstrated that pre-treatment with garlic extract can lead to significant dose-related reductions in the frequencies of gamma-radiation-induced (2 Gy) micronucleated polychromatic erythrocytes. The anticlastogenic effect of garlic extract was observed against lower radiation doses of 0.5 and 1 Gy, but not 0.25 Gy. Significant increases in the sulfhydryl content and glutathione S-transferase activity were observed after either pre-treatment with garlic extract or irradiation. However, the irradiated garlic-extract pre-treated animals showed a significant reduction in sulfhydryl content and glutathione S-transferase activities.
51 citations
TL;DR: A formal statement, of fuzzy functional independency, is introduced, which expresses the fact that the corresponding restricted fuzzy functional dependency is not a legitimate constraint of the real world.
50 citations
TL;DR: In this article, a simple hierarchical classification of wetlands based on their location (coastal or inland), salinity (saline or freshwater), physiognomy (herbaceous or woody), duration of flooding (permanent or seasonal) and the growth forms of the dominant vegetation is proposed.
Abstract: The Indian subcontinent has a large variety of freshwater, saline and marine wetlands. Whereas the mangroves are relatively well documented, very little is known about the other wetlands, with few exceptions. Only recently an inventory of these welands has been prepared but no effort has been made to classify them. A vast majority of the inland wetlands are temporary and/or man-made, and they have been traditionally used and managed by the local human populations. In this paper, first, we evaluate the classification schemes of the IUCN, US Fish and Wildlife Services and those of the Australian wetlands, for their applicability to Indian wetlands. Then, we propose a simple hierarchical classification of wetlands based on their location (coastal or inland), salinity (saline or freshwater), physiognomy (herbaceous or woody), duration of flooding (permanent or seasonal) and the growth forms of the dominant vegetation. We stress upon the hydrological factors which determine all the structural and functional characteristics of the wetlands. We consider that the various growth forms of wetland vegetation integrate the totality of hydrological variables and therefore, can be used as the indicators of different hydrological regimes.
49 citations
TL;DR: N-terminal sequence analysis showed that transcription is required for the overexpression of stress proteins in Leuconostoc mesenteroides, and these proteins were homologous to the highly conserved chaperone proteins DnaK and GroEL of Escherichia coli, respectively.
Abstract: The mechanism of adaptation of bacteria to survive at elevated temperature in the human host and the expression of heat-shock proteins in response to stress was examined by labelling with [35S]methionine. An increase in culture temperature from 26 °C to 37 °C induced expression of certain bacterial proteins (70 and 60 kDa). Heat shock at 40 °C, cold shock (10 °C), ethanol treatment or arsenite treatment also led to an increased expression of heat shock proteins of 70 and 60 kDa. Actinomycin D completely blocked the induction, indicating that transcription is required for the overexpression of stress proteins in Leuconostoc mesenteroides. N-terminal sequence analysis showed that these proteins were homologous to the highly conserved chaperone proteins DnaK and GroEL of Escherichia coli, respectively.
01 Jan 1995
TL;DR: Sustainability refers to productive performance of a system over time as mentioned in this paper, which implies use of natural resources to meet the present needs without jeopardizing the future potential, and is defined by the Technical Advisory Committee of the Consultative Group of International Agricultural Research (TAC).
Abstract: Sustainability refers to productive performance of a system over time. It implies use of natural resources to meet the present needs without jeopardizing the future potential. The concept has an undefined time dimension. The magnitude of the time dimension depends on one’s objectives, being shorter for economic factors and longer for concerns pertaining to environment, soil productivity, and land degradation. The shorter time dimension is generally less than a decade, while the longer time span may be up to five decades or more. The time dimension is also clearly addressed in the definition of sustainability adopted by the Technical Advisory Committee of the Consultative Group of International Agricultural Research: “Successful management of resources for agriculture to satisfy changing human needs while maintaining or enhancing the quality of the environment and conserving natural resources” (TAC, 1989).
TL;DR: The present review presents new developments in the potential use of biological tools such as arbuscular mycorrhizal fungi (AMF), which should ensure adequate levels of food production with satisfactory reduction of chemical fertilizer and pesticides, in the context of technologies needed for sustainable agriculture.
Abstract: In the last few years, urbanization and changes in eating habits have caused a significant shift toward the consumption of fresh fruits, leafy green salads, and vegetables. This has been followed by a growing commercialization of ornamental plants. These products come from a labor- and capital-intensive activity, where chemical inputs play an essential role but also brings with it a set of problems linked to the degradation of the natural environment and resource base. The present review presents new developments in the potential use of biological tools such as arbuscular mycorrhizal fungi (AMF), which should ensure adequate levels of food production with satisfactory reduction of chemical fertilizer and pesticides, in the context of technologies needed for sustainable agriculture. The potential of mycorrhizal fungi as biofertilizers and bioprotectors to enhance crop production is well recognized, but not well exploited because of the current agronomic practices, with their implications for the en...
TL;DR: Results indicate that phytochrome-mediated light regulation of NR and phyI gene expression may involve certain common steps in the signal transduction pathway such as the PI cycle and protein phosphorylation by a PKC-type enzyme.
Abstract: We have explored the possible involvement of the phosphoinositide (PI) cycle and protein kinase C (PKC) in the phytochrome (Pfr)-mediated light signal transduction pathway using nitrate reductase (NR) and phytochrome-I (PhyI) genes as model systems. We have shown earlier that phorbol myristate acetate (PMA) completely replaces the red light effect in stimulating nitrate reductase activity and transcript levels in maize. In this paper, we present detailed evidence to show that PMA mimics the red light effect and follows similar kinetics to enhance NR steady-state transcript accumulation in a nitrate-dependent manner. We also show that PMA inhibits phyI steady-state transcript accumulation in a manner similar to red light, indicating that a PKC-type enzyme(s) may be involved in mediating the light effect in both cases. Serotonin or 5-hydroxytryptamine (5-HT), a stimulator of PI turnover, was also found to mimic the red light effect in enhancing NR transcript levels and inhibiting phyI transcript accumulation, indicating the role of the PI cycle in generating second messengers for regulating the two genes. These results indicate that phytochrome-mediated light regulation of NR and phyI gene expression may involve certain common steps in the signal transduction pathway such as the PI cycle and protein phosphorylation by a PKC-type enzyme.
TL;DR: The homogeneous state and the node-synchronized state are both shown to occur for particular values of the parameters and coupling constants, and a general procedure is given to deduce the eigenvalue spectrum for these states.
Abstract: We study coupled maps on a Cayley tree, with local (nearest-neighbor) interactions, and with a variety of boundary conditions. The homogeneous state (where every lattice site has the same value) and the node-synchronized state (where sites of a given generation have the same value) are both shown to occur for particular values of the parameters and coupling constants. We study the stability of these states and their domains of attraction. Since the number of sites that become synchronized is much higher compared to that on a regular lattice, control is easier to achieve. A general procedure is given to deduce the eigenvalue spectrum for these states. Perturbations of the synchronized state lead to different spatiotemporal structures. We find that a mean-field-like treatment is valid on this (effectively infinite dimensional) lattice.
TL;DR: The modulatory influence of camphor on the activities of hepatic phase I and phase II drug metabolising enzymes and the levels of hepatics and extrahepatic reduced glutathione contents in the mouse were studied.
TL;DR: In this paper, a study was conducted on the size distribution and mineral characteristics of the suspended sediments of the Ganges river and is reported here, showing that most of the sediment load has a size range between <4-5.75 φ.
Abstract: With a mean annual flow of 5.9×1011m3yr−1 and sediment load of 1600x1012gyr−1 the Ganges river ranks second and third, respectively, in terms of water flow and sediment load among the world's rivers. Considering the enormous sediment transport by Ganges to the Bay of Bengal, a study was conducted on the size distribution and mineral characteristics of the suspended sediments of the Ganges river and is reported here. Most of the sediment load has a size range between <4–5.75 φ). The sediments are mostly medium to coarse silt and are poorly sorted. Mica dominates among the clay minerals, followed by chlorite, vermiculite, kaolinite, and smectite. Due to differences in geology, smectite becomes a major clay mineral in downstream rivers. At Calcutta, the clay mineral transport in millions of tons per year is 18,464, 8000, and 2147, for mica, smectite, and chlorite, respectively.
Journal Article•
TL;DR: The study points out that hypersalinity signals affect the lipid composition which in turn affects the membrane fluidity of C. membranefaciens, which favours osmotic adaptation against NaCl stress.
Abstract: The effect of hypersaline stress on the lipid composition of the salt-tolerant yeast Candida membranefaciens was studied. Fatty acid analyses of the plasma membrane showed a growth phase- and dose-dependent increase in the level of linolenic acid (C18:3) in 1.35 M NaCl-stressed cells. Palmitoleic acid (C16:1) was completely undetectable at all phases of the life cycle. Changes in the levels of other fatty acids were insignificant. The degree of unsaturation of fatty acids in the plasma membranes was higher in presence of 1.35 M NaCl. The fluorescence polarisation value of DPH (1,6-diphenyl- 1,3,5-hexatriene) in the spheroplasts of the stressed cells was lower as compared to the control cells, indicating the fact that a higher membrane fluidity favours osmotic adaptation against NaCl stress. Among different phospholipids, levels of Phosphatidylinositol and Phosphatidylethanolamine were elevated in the salt-adapted cells as compared to their controls. The levels of Phosphatidylcholine and cardiolipin did not change significantly in response to hypersaline stress. The study points out that hypersalinity signals affect the lipid composition which in turn affects the membrane fluidity of C. membranefaciens.
TL;DR: Itano et al. as mentioned in this paper analyzed the environment-induced decoherence theory, where the spontaneous emission lifetime of the relevant level emerges as the “decoherence time”.
TL;DR: It is concluded that the major mechanism by which bis(benzyl)polyamine analogs act may be by disruption of macromolecular biosynthesis and cell death andression of polyamines by these analogs may be yet another factor involved in slowing the growth of the parasite.
TL;DR: The results showed that DPH fluorescence polarization increased both in the microsome as well as in the synaptosome in REMS-deprived animals, except in the cerebellum, indicating that there was a generalized decrease in membrane fluidity in the rat brain.
Journal Article•
TL;DR: The enhanced cellular protein phosphorylation in hyaluronic acid stimulated cauda spermatozoa is demonstrated for the first time and strongly suggests the biological importance of hyaluronan binding protein phosphORYlation in the transduction of signals resulting from the interaction ofhyaluronate with the sperm surface.
Abstract: The present study was carried out to explore the mechanisms underlying hyaluronan-induced sperm motility. We demonstrate for the first time the enhanced cellular protein phosphorylation in hyaluronic acid stimulated cauda spermatozoa. Labeling of spermatozoa with [Pi] orthophosphoric acid yielded a wide range of labeled phosphoproteins in presence of hyaluronan. Under these experimental conditions, we further show tyrosine specific phosphorylation of proteins. In addition, this is also the first report showing enhanced phosphorylation of 34 kDa hyaluronan binding protein in response to hyaluronan. The role of 34 kDa hyaluronan binding protein in hyaluronan-induced spermatozoa is supported by elevated production of inositol triphosphate accompanied by increased phosphorylation in Triton X-100 insoluble cytoskeletal proteins. The evidence strongly suggests the biological importance of hyaluronan binding protein phosphorylation in the transduction of signals resulting from the interaction of hyaluronate with the sperm surface.
01 Jan 1995
TL;DR: Arbuscular mycorrhizas are the most widely spread type of fungal plant-root symbiosis, and the zygomycetes involved in these associations are often the most abundant fungi known in soil from all the continents.
Abstract: Arbuscular mycorrhizas (AM) are the most widely spread type of fungal plant-root symbiosis, and the zygomycetes involved in these associations are often the most abundant fungi known in soil from all the continents (Harley 1991). Fungi closely resembling mycorrhizal fungi have also been described in the underground organs of fossils of early land plants, suggesting that roots and the mycorrhizal fungi probably have evolved together and are likely to have produced combinations suitably adapted for survival within the biotic communities of their origin (Simon et al. 1993).
TL;DR: The data indicated that Hsp expressed in response to stress encountered in macrophages may confer protection to parasites and play a crucial role in their survival in the mammalian host.
TL;DR: Evidence is suggested to suggest that there are several PDR homologues present in C. albicans which display multidrug resistance and a collateral sensitivity pattern different from PDR 5 and CDR 1.
Abstract: By functional complementation of a PDR 5 (pleiotropic drug resistance) null mutant of S. cerevisiae, we have recently cloned and sequenced a multidrug resistance gene CDR 1 (Candida Drug Resistance). Transformation by CDR 1 of a PDR 5 disrupted host hypersensitive to cycloheximide and chloramphenicol resulted in resistance to these as well as other unrelated drugs. The nucleotide sequence of CDR 1 revealed that, like PDR 5, it encodes a putative membrane pump belonging to the ABC superfamily. CDR 1 encodes a protein of 169.9 kDa whose predicted structural organisation is characterised by two homologous halves, each comprising a hydrophobic region, with a set of six transmembrane stretches, preceded by a hydrophilic binding fold. We now have evidence to suggest that there are several PDR homologues present in C. albicans which display multidrug resistance and a collateral sensitivity pattern different from PDR 5 and CDR 1. The functions of such genes and their products in the overall physiology of C. albicans is not yet established.
TL;DR: In this paper, the authors proposed that the collapse does occur, and it can be explained by the ''environment induced decoherence'' theory, and they showed that the spontaneous emission life time of the atom sets a fundamental limit on the requirement of continuous measurements.
Abstract: The experiment of Etano et al which demonstrated the quantum Zeno effect (QZE) in an optical experiment was explained by Frerichs and Schenzle without invoking the wave function collapse. In this report it is proposed that the collapse does occur, and it can be explained by the `environment induced decoherence' theory. The environment here consists of the completely quantized field vacuum modes. The spontaneous emission life time of the atom sets a fundamental limit on the requirement of `continuous measurements' for QZE. This limit turns out to be related to the time-energy uncertainty relation discussed by Ghirardi et al.
TL;DR: In this article, a dynamical model for the collapse of the wave function in a quantum measurement process is proposed by considering the interaction of a quantum system (spin - 1 2 ) with a macroscopic quantum apparatus interacting with an environment in a dissipative manner.
Abstract: A dynamical model for the collapse of the wave function in a quantum measurement process is proposed by considering the interaction of a quantum system ( spin - 1 2 ) with a macroscopic quantum apparatus interacting with an environment in a dissipative manner. The dissipative interaction leads to decoherence in the superposition states of the apparatus, making its behaviour classical in the sense that the density matrix becomes diagonal with time. Since the apparatus is also interacting with the system, the probabilities of the diagonal density matrix are determined by the state vector of the system. We consider a Stern-Gerlach type model, where a spin - 1 2 particle is in an inhomogeneous magnetic field, the whole set up being in contact with a large environment. Here we find that the density matrix of the combined system and apparatus becomes diagonal and the momentum of the particle becomes correlated with a spin operator, selected by the choice of the system-apparatus interaction. This allows for a measurement of spin via a momentum measurement on the particle with associated probabilities in accordance with quantum principles.
TL;DR: Neither the various steps to bring down labour intensity in the farm sector, nor the falling standard of living in rural areas, could bring about migration from rural to urban areas.
Abstract: This article seeks to analyse agrarian structure and policy in the Soviet period and discuss their effect on migration from rural to urban areas. In the case of [Soviet] Central Asia neither the various steps to bring down labour intensity in the farm sector nor the falling standard of living in rural areas could bring about migration from rural to urban areas. This was because in traditional societies economic mechanisms are not effective unless they are complemented by appropriate social and cultural policies. All policies were oriented towards the states goal of vertical integration of regions with the central economy. In Central Asia in particular this policy resulted in serious distortions in the social and economic spheres. (EXCERPT)