Showing papers by "Jadavpur University published in 1994"
TL;DR: The possibility of discovering heavy Majorana neutrinos and lepton number violation via the like-sign dilepton signal at hadron supercolliders is investigated and the suppression of the standard model background by suitable kinematical cuts is discussed.
Abstract: The possibility of discovering heavy Majorana neutrinos and lepton number violation via the like-sign dilepton signal at hadron supercolliders is investigated The cross sections for the production of these neutrinos singly as well as in pairs are computed both in three- and four-generation scenarios within the framework of the gauge group SU(2${)}_{\mathit{L}}$\ensuremath{\bigotimes}U(1${)}_{\mathit{Y}}$ and the dominant processes are identified The suppression of the standard model background by suitable kinematical cuts is also discussed
144 citations
143 citations
TL;DR: In this paper, a retrograde P-T trajectory of the granulite complex at Anakapalle, which was metamorphosed at ~1000 Ma, was deduced.
Abstract: The granulite complex at Anakapalle, which was metamorphosed at ~1000 Ma, comprises orthopyroxene granulites, leptynite, khondalite, mafic granulites, calc-silicate rock, spinel granulites, and two types of sapphirine granulites-one quartz-bearing and migmatitic and the other devoid of quartz and massive. Reaction textures in conjunction with mineral-chemical data suggest several continuous and discontinuous equilibria in these rocks. In orthopyroxene granulites, dehydration-melting of biotite in the presence of quartz occurred according to the reaction biotite+quartz= garnet (Py 37 )+K-feldspar+orthopyroxene + liquid. Later, this garnet broke down by the reaction garnet (Py 37 )+quartz = orthopyroxene + plagioclase. Subsequently, coronal garnet (Py 30 ) and quartz were produced by the same reaction but proceeding in the opposite direction. In spinel granulites, garnet (Py 42 ) and sillimanite were produced by the breakdown of spinel in the presence of quartz. In the two types of sapphirine granulites, garnet with variable pyrope content broke down according to the reaction garnet = sapphirine + sillimanite + orthopyroxene. The highest pyrope content (59 mol %) was noted in garnets from quartz-free sapphirine granulites compared with the quartz-bearing one (53 mol % pyrope). The calculated positions of the mineral reactions and diserete P-T points obtained by thermobarometry define a retrograde P-T trajectory during which a steep decompression of ~1.5 kbar from P-T max of 8 kbar and 900 °C was followed by near-isobaric cooling of ~300 °C. During this decompression, garnet with variable pyrope contents in different rocks broke down on intersection with various divariant equilibria. Near-isobaric cooling resulted in the formation of coronal garnet around second-generation orthopyroxene and plagioclase replacing earlier porphyroblastic garnet in orthopyroxene granulites. It has been argued that the deduced P-T trajectory originated in an extensional regime involving either a crust of near-normal thickness of a slightly overthickened crust owing to magmatic underaccretion.
90 citations
TL;DR: Results suggest experimental diabetes, induced by streptozotocin, can produce biochemical changes not only in pancreas but also in liver, kidney and brain tissue.
Abstract: Levels of lipid peroxidation in liver, kidney, brain and blood, liver glutathione (GSH) and several enzymes in liver tissue associated with antioxidant defence mechanism, namely Catalase (EC: 1.11.1.6), GSH reductase (EC:1.6.4.2) and GSH-S-transferase (EC: 2.5.1.18), were investigated in streptozotocin-induced diabetic rats. The single intraperitoneal injection of streptozotocin (65 mg/kg) caused a four-, eight- and seven-fold increase in lipid peroxidation in brain, liver and kidney, respectively. A decline in GSH levels both in blood (two-fold) and liver (16%) compared with normal counterparts was also observed. A marginal increase in catalase activity, a 20% decrease in GSH reductase and an increase of GSH-S-transferase activity was also found in this experimental diabetic condition. These results suggest experimental diabetes, induced by streptozotocin, can produce biochemical changes not only in pancreas but also in liver, kidney and brain tissue.
86 citations
TL;DR: In this paper, Sarkar et al. showed that separating the structures of different generations is necessary for a proper understanding of the field features taken to indicate arrested formation of charnockites in South India and elsewhere.
74 citations
TL;DR: The ability of this extract (at 100 mg/kg) to lower TG and TC in serum and its antiatherosclerotic potential were almost similar to that of a standard lipid lowering agent—clofibrate.
Abstract: Gymnema sylvestre R. Br. leaf extract (25–100 mg/kg) when orally administered to experimentally induced hyperlipidaemic rats for 2 weeks, reduced the elevated serum triglyceride (TG), total cholesterol (TC), very low-density lipoprotein (VLDL)-and low-density lipoprotein (LDL)-cholesterol in a dose-dependent manner. The decreased serum high-density lipoprotein (HDL)-cholesterol and antiatherogenic index (AAI) in hyperlipidaemia were also reversed towards normalization. The ability of this extract (at 100 mg/kg) to lower TG and TC in serum and its antiatherosclerotic potential were almost similar to that of a standard lipid lowering agent—clofibrate.
70 citations
TL;DR: In this article, a detailed study in Maihar, Madhya Pradesh, reveals upward transition from marine to fluvial through a mixed facies association also bearing eolian imprints.
55 citations
TL;DR: In this paper, the authors derived an equation which relates the critical fracture spacing with layer thickness, tensile strength of the layer material/viscosity of the embedding medium ratio (τo/η), and bulk strain rate (eb).
55 citations
Journal Article•
TL;DR: The results show insulin-like in vivo action of selenium in diabetic mice, and selenite treatment of diabetic mice restored these parameters to near control values.
Abstract: The effect of oral administration of sodium selenite on glucose homoeostasis was studied in male Swiss albino mice 6 weeks after they were made diabetic with streptozotocin. Diabetes caused hyperglycaemia (2.5-fold), a marked decrease (4.5-fold) in liver glycogen, a 4-fold increase in the glucose-6-phosphatase activity and significant decrease in plasma insulin levels and protein kinase activity. Although selenium administration in control animals showed no significant effect on various parameters measured, selenite treatment of diabetic mice restored these parameters to near control values. Thus the results show insulin-like in vivo action of selenium in diabetic mice.
51 citations
02 Oct 1994
TL;DR: The insulated gate bipolar transistor (IGBT) combines the advantages of both MOS and bipolar transistor technologies into a near-ideal power semiconductor switch as discussed by the authors, which is used in the half or full-bridge power convertor configuration.
Abstract: The insulated gate bipolar transistor (IGBT) combines the advantages of both MOS and bipolar transistor technologies into a near-ideal power semiconductor switch. Of the various application areas, the use of IGBTs in the half or full-bridge power convertor configuration is very common. Such applications have typical requirements like isolated drivers, high dv/dt stress withstand, protection against shoot-through fault, etc. This paper presents various types of gate drive circuits suitable for such situations and their relative performance under actual circuit conditions. This includes pulse-transformer circuits (where a secondary power supply is not required) for PWM control, as well as opto-isolator circuits where the secondary power supply may be derived from the inverter DC bus. Protection schemes for the IGBT that can be incorporated into the drive circuit are also discussed. >
49 citations
TL;DR: In this article, the effects of an inflow of foreign capital on social welfare were analyzed in a mobile-capital, Harris-Todaro economy, in which all income earned by foreign capital is repatriated, and in which there is no tariff.
TL;DR: The results confirm the fact that BC is particularly protective in limiting the action of 2-AAF during the initiation phase of hepatocarcinogenesis.
Abstract: The dietary administration of beta-carotene (BC; 100 mg/kg food) daily has been found to be highly effective in reducing cancer incidence in male Sprague-Dawley rats fed 2-acetyl-aminofluorene (0.05% in food). BC treatment either before initiation, during initiation and selection/promotion phases of hepatocarcinogenesis have been found to be effective in elevating hepatic microsomal cytochrome b5 (24-50%), P-450 (18-38.5%), NADPH cytochrome c reductase (17.5-43.25%) and cytosolic aryl hydrocarbon hydroxylase (60.5-63.5%) activity to a statistically significant level measured either in the hyperplastic nodule (HN) or in the non nodular surrounding liver parenchyma (NNSP) compared to carcinogen control. Moreover, BC treatment throughout the study decrease the cytosolic 1-chloro-2,4-dinitrobenzene conjugated glutathione S-transferase (38.9-51.22%) and microsomal UDP-glucuronyl transferase (37.3-59.1%) activities to a significant level when compared to carcinogen control rats. A decrease in the number of hyperplastic nodules and their total liver parenchyma occupied were also observed in BC treated groups. Furthermore, a direct correlation between HNs and NNSP liver areas were observed with the hepatic BC and vitamin A contents and also with the rates and patterns of hepatic drug metabolism. Our results confirm the fact that BC is particularly protective in limiting the action of 2-AAF during the initiation phase of hepatocarcinogenesis.
TL;DR: In this article, four dihaloruthenium(II) complexes of general formula Ru(PPh 3 ) 2 (L)X 2 [L = 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen); X = Cl, Br] have been synthesized by the reaction of L with Ru (PPh3 ) 3 X 2 in dichloromethane.
01 Sep 1994
TL;DR: In this article, the authors highlight critical observations made in the course of investigations on surge performance of a transformer winding by analogue modelling and confirm appropriate methods of fault detection on fault occurrence in specified sections along the winding.
Abstract: The paper highlights some critical observations made in the course of investigations on surge performance of a transformer winding by analogue modelling. The studies cover winding responses to both full and chopped standard lightning impulses where time-to-chop was varied over a wide range to find the maximum stresses across winding discs. Three specific zones along the winding were selected for studies. These were the line-end and earth-end sections each spanning about 6% of the entire winding length, while the midwinding disc was chosen to represent the midwinding section. Two types of faults were simulated: series faults both permanent and voltage-dependent; and parallel faults through resistance with preset faulting levels. Winding responses to faults under impressed impulses were observed and scanned using both neutral-current (Hagenguth) and tank-current methods of fault detection. Important observations are corroborated by oscillograms of winding responses. The results suggest and confirm appropriate methods of fault detection on fault occurrence in the specified sections along the winding. >
TL;DR: The photophysical behavior of the dye safranine T has been studied in several polar and non-polar solvents and in micellar solution (non-ionic and ionic surfactants).
Abstract: The photophysical (visible and fluorescence) behavior of the dye safranine T has been studied in several polar and non-polar solvents and in micellar solution (non-ionic and ionic surfactants). The change in the dipole moment of the dye between the ground and excited states has been estimated using approximate sovent-induced spectral shift (Stokes shift) theories based on non-specific interactions. The dependence of the dye behaviour on the nature of the micellar interface is shown by the Strokes shift which exhibits an inverse dependence on the average aggregation number of the surfactant micelles. A reasonables estimation of the dielectric constant of the micellar interface has been attempted.
TL;DR: The authors' data of target associated slow particles reveal similar type of increase in SFMs with decreasing bin width of the angular distribution, which contradicts the existing concept of evaporation model that the statistical equilibrium is reached before the emission of fragmented particles from residual target nuclei at high-energy nuclear interactions.
Abstract: We analyze the angular distribution of target-associated slow particles in high-energy nuclear interactions, in terms of scaled factorial moments (SFMs). A power-law type behavior of SFMs, popularly known as ``intermittency,'' is a diagnostic indicator of possible dynamical phenomenon in multiparticle production and multifragmentation processes in high-energy physics. Our data of target associated slow particles reveal similar type of increase in SFMs with decreasing bin width of the angular distribution. The new observation thus contradicts the existing concept of evaporation model that the ``statistical equilibrium'' is reached before the emission of fragmented particles from residual target nuclei at high-energy nuclear interactions.
TL;DR: In this paper, the authors considered a small open Harris-Todaro economy with the urban sector consisting of a duty-free zone and a non-duty free zone, where capital mobility is perfectly shiftable between the two sub-sectors.
Abstract: We consider a small open Harris-Todaro economy with the urban sector consisting of a “duty-free zone” and a “non-duty free zone” There is no capital mobility between the urban sector and the rural sector, but capital is perfectly shiftable between the two sub-sectors of the urban sector A policy of expanding the duty-free zone through the reduction in import-duty on intermediate goods in that sector ultimately lowers the level of output of that sector This policy also raises the level of unemployment, lowers national income (social welfare), and increases economic inequality If, however, the tariff on the final product is reduced in that sector, we get the opposite result
TL;DR: A modified time-lag model for the control of the secretion of the hormone testosterone is proposed and questions concerning small amplitude oscillations of solutions are addressed analytically and numerically.
Abstract: A modified time-lag model for the control of the secretion of the hormone testosterone is prosposed. Conditions for switching of the steady state from stable to unstable are derived. Questions concerning small amplitude oscillations of solutions are addressed analytically and numerically.
TL;DR: A mixed ligand ruthenium-quinone complex, Ru(trpy)(DBQ)Cl [trpy = 2,2′: 6′,2″-terpyridine, DBQ = 3,5-di-tert-butylquinone] has been synthesized as mentioned in this paper.
TL;DR: In this article, a multilayer feed-forward NN with a back-propagation algorithm is designed for electrode contour optimization. But the results from the present study show that the trained NN can give optimized electrode contours to get a desired stress distribution on the electrode surface very efficiently and accurately.
Abstract: In this paper artificial neural networks (NN) with supervised learning are proposed for HV electrode optimization. To demonstrate the effectiveness of artificial NN in electric field problems, a simple cylindrical electrode system is designed first where the stresses can be computed analytically. It is found that once trained, the NN can give results with mean absolute error of /spl sim/1% when compared with analytically obtained results. In the next section of the paper, a multilayer feedforward NN with a back-propagation algorithm is designed for electrode contour optimization. The NN is first trained with the results of electric field computations for some predetermined contours of an axisymmetric electrode arrangement. Then the trained NN is used to give an optimized electrode contour in such a way that a desired stress distribution is obtained on the electrode surface. The results from the present study show that the trained NN can give optimized electrode contours to get a desired stress distribution on the electrode surface very efficiently and accurately. >
TL;DR: In this article, the behavior of a downdraft rice husk gasifier with diameter 200 mm and height 940 mm has been studied and the gasification rate was varied in the range 1.8-4.3 × 10−2 kg/m2s.
Abstract: The behaviour of a downdraft rice husk gasifier of diameter 200 mm and a height 940 mm has been studied. The gasification rate was varied in the range 1.8–4.3 × 10−2 kg/m2s. The air velocity was varied in the range 0.032–0.099 m/s. The producer gas obtained from the gasifier has a calorific value in the range 3240–4382 kJ/m3. A set of theoretical kinetic equations on the assumption of nonequilibrium conditions has been developed and solved numerically. The simulated temperature profile and outlet gas composition have been compared with those obtained from experimental runs. The model developed from a mechanistic approach is found to explain the behaviour of the present system appreciably within the range of variables studied.
TL;DR: In this paper, a transect of the Bay of Bengal is analyzed using multi-channel seismic reflection, magnetic and bathymetric data collected along a traning, 1110 km long parallel to 13° N latitude across the Bay Of Bengal.
Abstract: Analysis of the multi-channel seismic reflection, magnetic and bathymetric data collected along a transect, 1110 km long parallel to 13° N latitude across the Bay of Bengal was made. The transect is from the continental shelf off Madras to the continental slope off Andaman Island in water depths of 525 m to 3350 m and across the Western Basin (bounded by foot of the continental slope of Madras and 85° E Ridge), the 85° E Ridge, the Central Basin (between the 85° E Ridge and the Ninetyeast Ridge), the Ninetyeast Ridge and the Sunda Arc. The study revealed eight seismic sequences, H1 to H8 of parallel continuous to discontinuous reflectors. Considering especially depth to the horizons, nature of reflection and on comparison with the published seismic reflection results of Currayet al. (1982), the early Eocene (P) and Miocene (M) unconformities and the base of the Quaternary sediments (Q) are identified on the seismic section. Marked changes in velocities also occur at their boundaries. In the Western Basin the acoustic basement deepening landward is inferred as a crystalline basement overlain by about 6.7 km of sediment. In the Central Basin possibly thicker sediments than in the Western Basin are estimated. The sediments in the Sunda Arc area are relatively thick and appears to have no distinct horizons. But the entire sedimentary section appears to be consisting of folded and possibly faulted layers. The comparatively broader wavelength magnetic anomalies of the Central Basin also indicate deeper depth of their origin. Very prominent double humped feature of the 85° E Ridge and broad basement swell of the Ninetyeast Ridge are buried under about 2.8 km thick sediments except over the prominent basement high near 92° E longitude. The positive structural relief of the buried 85° E Ridge in the area is reflected in magnetic signature of about 450 nT amplitude. Flexural bulge of the 85° E Ridge and subsidence of the Ninetyeast Ridge about 24 cm my−1 rate since early Eocene period have been inferred from the seismic sequence analysis.
TL;DR: Findings imply that FB1 exposure may become a potential problem in India and may lead to decreased immune responses with consequent susceptibility of a host to infection.
Abstract: The natural occurrence of fumonisin B 1 (FB 1 ) in Indian maize and its impact on the viability and phagocytosis of chicken peritoneal macrophages in vitro were investigated. FB 1 was found to be present at the levels of 300-366 ppm in Fusarium moniliforme-infected maize grains. The infected kernels in a population of 100 ears showed normal (Gaussian) frequency distribution. FB 1 , extracted from the contaminated kernels, reduced the viability and phagocytic activity of macrophages. These findings imply that FB 1 exposure may become a potential problem in India and may lead to decreased immune responses with consequent susceptibility of a host to infection
TL;DR: In this paper, a computer-rated transmission expansion planning approach using the network simplex technique is proposed, which uses variable load structure and generator cost curves for economic generation, assuming an increased load demand, an optimum network configuration is designed.
TL;DR: In this paper, a jute-stick gasification process was studied at steady-state conditions in a laboratory moving-bed updraft system, where an insulated cylindrical MS reactor of constant i.d. was used as gasifier, including an ash disposal unit.
TL;DR: A method for the exact determination of the remaining cladding thickness (h) of a polished single-mode fiber, from the measurement of the throughput attenuation, is shown.
Abstract: A method for the exact determination of the remaining cladding thickness (h) of a polished single-mode fiber, from the measurement of the throughput attenuation, is shown. Experimental loss variations with h are verified with the theoretical expression of the loss coefficient, which depends on the fiber parameters, source wavelength, and refractive index of the liquid placed over the polished fiber.
TL;DR: In this article, a Tolman-Bondi type inhomogeneous, spherically symmetric metric is obtained in an (n+2)-dimensional spacetime withn≥2.
Abstract: A Tolman-Bondi type inhomogeneous, spherically symmetric metric is obtained in an (n+2)-dimensional spacetime withn≥2. The metric form admits the familiar shell focusing singularity which, depending on the inhomogeneity parameter, may become naked. Moreover, for the particular case of a marginally bound collapsing model one may also obtain strong-curvature singularities, which provides yet another counterexample to the cosmic censorship hypothesis. It is interesting to point out that it is the assumption of self similarity rather than spherical symmetry which determines the nature of the singularity. This, however, extends an earlier observation of Lake and Zannias in four-dimensional spacetime.
TL;DR: It is concluded that M. cordata root extract possesses antiulcer activity and that the observed activity may be due to the modulation of defensive factors through an improvement of gastric cytoprotection.
Abstract: The effect of the methanolic fraction of Mikania cordata (Burm., B. L. Robinson) root extract was investigated for its possible ulceroprotective activity in male Sprague-Dawley rats. Oral administration of this extract (50, 100, or 150 mg/kg) significantly prevented the occurrence of water immersion stress-induced gastric ulcers in a dose-responsive manner. The extract also dose-dependently inhibited gastric ulcers induced by ethanol, aspirin, and phenylbutazone. The ED50 values of the extract in the above four ulcer models were found to be 95.1, 109.7, 125.5, and 136.2 mg/kg, respectively. The volume, acidity, and peptic activity of the gastric juice in pylorous-ligated rats were not altered upon administration of the extract (100 or 150 mg/kg) but it significantly and dose-dependently promoted the gastric mucus secretion in normal as well as stress- and ethanol-induced ulcerated animals. Based on these results, we conclude that M. cordata root extract possesses antiulcer activity and that the observed activity may be due to the modulation of defensive factors through an improvement of gastric cytoprotection.
TL;DR: In this paper, the existence of non-statistical fluctuations in the azimuthal plane of interaction in high energy relativistic interactions initiated by 16O at 2.1 GeV and 12C and 24Mg at 4.5 GeV/nucleon was revealed.
Abstract: Analysis of target fragmented 'black' particles in nuclear emulsion from high energy relativistic interactions initiated by 16O at 2.1 GeV/nucleon and 12C and 24Mg at 4.5 GeV/nucleon reveal the existence of nonstatistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus.
TL;DR: In this article, the authors have successfully designed and developed an Electrochemical Machining set-up with a microprocessor-controlled stepper motor drive control unit for providing variable and automatic tool feed rates and also with an electronic circuit for auto-sensing of changes of the ECM gap condition during the course of machining, so as to actuate the auto-feedback control of the tool feed-rate and thus secure constant current Electrochemical machining.