Showing papers by "North Eastern Hill University published in 1993"
TL;DR: In this article, the one-loop radiative corrections to the mass squared matrix of the CP-even Higgs bosons in the non-minimal supersymmetric standard model containing two Higgs doublets and a Higgs singlet chiral superfield were presented.
92 citations
TL;DR: The diversity of fungal species increased in earthworm casts after passing through the earthworm gut and demonstrated that the casts displayed more diverse fungal flora than the soil.
Abstract: Earthworm casts and adjacent uningested soil from 30 different locations were compared to determine the abundance and diversity of fungal species. The casts contained larger fungal populations (g-1 dry soil weight) and numbers of fungal species than the soil. Variations in these parameters between casts and soil were statistically significant (P=0.05). Fungal populations and the number of fungal species in casts and soil also varied significantly (P=0.05) between samples from different locations. A total of 27 fungal species were recorded from the casts and soil. Indices of dominance (0.084 casts; 0.14 soil) and general diversity (2.53 casts; 2.02 soil) demonstrated that the casts displayed more diverse fungal flora than the soil. The diversity of fungal species increased in earthworm casts after passing through the earthworm gut.
90 citations
TL;DR: In this paper, the dominant one-loop radiative corrections arising from quark-squark loops to the mass squared matrix of the CP-even Higgs bosons in a non-minimal supersymmetric standard model containing two Higgs doublets and a Higgs singlet chiral superfield were calculated.
Abstract: We calculate the dominant one-loop radiative corrections arising from quark-squark loops to the mass squared matrix of theCP-even Higgs bosons in a non-minimal supersymmetric Standard Model containing two Higgs doublets and a Higgs singlet chiral superfield using one-loop effective potential approximation. We use this result to evaluate upper and lower bounds on the radiatively corrected masses of all the scalar Higgs bosons as a function of the parameters of the model. We find that the one-loop radiative corrections are substantial only for the lightest Higgs boson of the model and can push its mass beyond the reach of LEP. We also calculate an absolute upper bound on the mass of the radiatively corrected lightest Higgs boson and compare it with the corresponding bound in the minimal supersymmetric Standard Model.
88 citations
TL;DR: Cellulose, amylase and invertase activities were studied in extracts of leaf litters of Alnus nepalensis and Pinus kesiya during litter decomposition at a roadside (more polluted) and a non-roadside (less polluted) forest stand.
Abstract: Cellulose, amylase and invertase activities were studied in extracts of leaf litters of Alnus nepalensis and Pinus kesiya during litter decomposition at a roadside (more polluted) and a non-roadside (less polluted) forest stand. Enzyme activities were considerably higher in litter at the less polluted than at the more polluted site. Cellulase and amylase activities showed a marked seasonal variation at both sites. Cellulase and amylase activities increased during litter decomposition, whereas invertase activity was higher at the begining of litter decomposition. Invertase activity correlated positively with litter soluble sugars. Cellulase and amylase activities, but not invertase activity, were correlated significantly with numbers of fungi and bacteria.
49 citations
TL;DR: Mycorrhizal infection was reduced by phosphate application, but markedly stimulated nodulation in Alnus seedlings, and the nitrogen content of the nodule was higher than that of the shoot of nodulated mycorrhIZal plants.
Abstract: SUMMARY Phosphate uptake by a tripartite association involving Frankia, Glomus and Alnus was studied in containerized seedlings of Alnus nepalensis D. Don. The response of non-mycorrhizal plants to P fertilization was more pronounced than their mycorrhizal counterparts. The yield of nodulated mycorrhizal plants was greater at low than at high P doses. At the highest P application, however, reduction in nodulation as well as nitrogenase activity was observed. Mycorrhizal infection was reduced by phosphate application, but markedly stimulated nodulation in Alnus seedlings. The nitrogen content of the nodule was higher than that of the shoot of nodulated mycorrhizal plants. Nodule dry weight, nitrogenase activity and nodule nitrogen content increased with increase in P application up to quantities typical of those in soil, after which it declined.
41 citations
TL;DR: The chloroallyl zinc reagent generated insitu by deprotonation of allyl chloride in the presence of lithium diisopropylamide and zinc chloride undergoes highly regio-and diastereoselective α-addition to carbonyl compounds to give syn chlorohydrins which on treatment with base afford cis vinyloxiranes in high yields as discussed by the authors.
28 citations
TL;DR: The inorganic NPK fertilizer in combination with organic manure had a significantly greater effect on earthworm activities thanNPK fertilizer alone, and therefore the addition of organic matter appears advisable in order to obtain maximum benefits from NPK fertilization in this soil.
Abstract: The effects of fertilization with N, P, K, and organic manure (alone or in combination) on earthworm populations, biomass, and casting activity were measured in a cultivated soil (organic C 1.5%, annual rainfall 2000–2300 mm). These applications of fertilizer caused significant increases in earthworm numbers, biomass, and casts. N alone or in combination with P and K also influenced these earthworm parameters significantly. The inorganic NPK fertilizer in combination with organic manure had a significantly greater effect on earthworm activities than NPK fertilizer alone, and therefore the addition of organic matter appears advisable in order to obtain maximum benefits from NPK fertilizer in this soil.
25 citations
TL;DR: An analogue of the Fundamental Theorem of Homomorphism and the Second Isomorphism Theorem for fuzzy homomorphisms is proved and the fuzzy subgroup generated by a fuzzy subset is studied.
24 citations
TL;DR: In this paper, a series of isomeric new dithiocyanate ruthenium(II) complexes of the type trans,cis-Ru(CNS)2L2[L = 2-(arylazo)pyridine] have been synthesized by a stereoretentive substitution reaction from the known diaquo cationic complex trans, cis-[Ru(OH2) 2L2]2+.
24 citations
TL;DR: In this article, the Ricci scalar R plays a dual role: like a physical field as well as a geometrical field under certain conditions, and the concept of phase transition and spontaneous symmetry breaking has been discussed incorporating a temperature-dependent Higgs-like potential for Ricci field.
18 citations
TL;DR: The triperoxovanadium(V) complexes, A[V(O2)3]·3H2O (A = Na or K), have been investigated in this article.
Journal Article•
TL;DR: In this paper, a new rapid air-drying technique for scanning electron microscopy (SEM) with results comparable to critical point drying (CPD) has been developed.
Abstract: A new rapid air-drying technique for scanning electron microscopy (SEM) with results comparable to critical point drying (CPD) has been developed. In earlier studies a trematode parasite and a fungus were used as test specimens. Here the application of the new method for SEM of some mammalian tissue is described. The method is based on drying the tissues from an organo-silicon compound whose physical and chemical properties make it the most appropriate fluid for tissue drying.
TL;DR: In this article, reformatsky regants are shown to undergo facile C C bond formation on trithiocarbonates, xanthates, thione and dithioesters, through carbophilic additional yielding products formed by elimination of either sulphur or alkylthio group.
TL;DR: The computation of the threshold effects in SU(5) with Higgs representations 24, 5, and 75 shows that the maximum allowed ${\ensuremath{\tau}}_{p}$ for reasonable superheavy Higgs boson masses is accessible to experimental tests at low energies.
Abstract: We find that the presence of a real scalar in the grand desert transforming as $\ensuremath{\zeta}(3, 0, 8)$ under $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}{(1)}_{Y}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(3)}_{C}$ ensures the agreement of the GUT predictions with the data from CERN LEP and proton lifetime (${\ensuremath{\tau}}_{p}$). The mass of $\ensuremath{\zeta}$ is predicted to be close to the Peccei-Quinn symmetry-breaking scale. The computation of the threshold effects in SU(5) with Higgs representations 24, 5, and 75 shows that the maximum allowed ${\ensuremath{\tau}}_{p}$ for reasonable superheavy Higgs boson masses is accessible to experimental tests at low energies. The additional predictions in SO(10) are small neutrino masses compatible with solutions to the solar-neutrino problem and the dark matter of the Universe.
TL;DR: Differences in the temporal and spectral pattern were found in the mating calls of morphologically alike specimens of Rana limnocharis, indicating that the present morphotypeRana lim nocharis in northeast India is composed of several species.
Abstract: Mating calls of three frog species abundant in northeast IndiaRana tigerina,Rana cyanophlyctis andRana limnocharis were recorded in the fields of Assam and Meghalaya during their breeding season (July-August, 1991). The calls were analysed for their temporal and spectral characters. They were species specific, with distinct call duration and call period, number of pulses per call and interpulse interval, and dominant frequency and frequency domain. A comparison of the mating calls ofRana cyanophlyctis with those of the siblingRana ehrenbergi from Yemen showed differences in their temporal and spectral characters, supporting the suggestion that these two species are distinct species, rather than subspecies of the same species. Differences in the temporal and spectral pattern were found in the mating calls of morphologically alike specimens ofRana limnocharis, indicating that the present morphotypeRana limnocharis in northeast India is composed of several species.
TL;DR: In this paper, the authors measured the electrical conductivity of sodium dodecyl sulfate (SDS) in SDS-acetic acid buffer solutions as functions of concentration, temperature and pH.
Abstract: Electrical conductivity of sodium dodecyl sulfate (SDS) in sodium acetate–acetic acid buffer solutions was measured as functions of concentration, temperature and pH. First and second critical micelle concentrations (cmc1 and cmc2) of these solutions were estimated. Plot of cmc1 versus pH passes through a minimum in the pH range 5.2 to 5.6. The decrease in cmc1 with increasing pH is shown to be due to the Na+ counterion and is described quantitatively by an analytical expression which also provides the value of counterion binding constant. The increasing tendency of cmc1 with increase in pH is, on the other hand, caused by the acetate co-ion. The enthalpy and standard free energy changes due to micellization of SDS were estimated. The slope of the specific conductivity versus concentration plot above cmc2 is found to decrease with increasing concentration of sodium acetate which is contrary to the trend reported in sodium chloride solution. This study has revealed the effect of the nature of co-ion on mic...
TL;DR: In this paper, a novel route for assembling cyclopent-[a]indene framework bearing useful functionalities has been developed through bis(methylthio) carbenium ion mediated Lewis acid induced tandem cyclization of bis-(methylthios) methylene aryl cyclopropyl ketones 1b-d and corresponding carbinols 11b−d.
TL;DR: The title pyrazoles were synthesized through cyclocondensation of hydroxyiminoimine derivatives 1a-j with hydrazine hydrate as mentioned in this paper, and they were shown to be pyrazolines.
TL;DR: In this paper, a cycloaddition with 1,3diaza-1,3-butadienes was used to generate cyclic nitrones with trisubstituted amidines.
TL;DR: In this paper, a method for the synthesis of novel complexes of composition (R 3 SnL 2 ) ClO 4 where L represents pyridine, γ-picoline, 2,2′-bipyridine and 1,10-phenanthroline; and R n Bu or Ph.
TL;DR: In this article, the concept of information is introduced again and connected to the most recent copper target experiments, and further developments of the ARBUZOV-Target using CR-39 detectors and relativistic heavy ions are given.
TL;DR: In this article, the authors studied the cycling of six mineral elements (N, P, K, Na, Ca and Mg) in a humid subtropical grassland at Cherrapunji, north-eastern India during 1988-1989.
Abstract: Cycling of six mineral elements (N, P, K, Na, Ca and Mg) was studied in a humid subtropical grassland at Cherrapunji, north-eastern India during 1988–1989. Elemental concentrations in the shoot of four dominant grass species,viz., Arundinella khaseana, Chrysopogon gryllus, Eragrostiella leioptera andEulalia trispicata were very low, and none of the species appears suitable for fodder use. Among different vegetation compartments, live root was the largest reservoir of all the nutrients (except Ca) followed by live shoot, dead shoot, litter and dead root. For Ca, live shoot was the major storage compartment. The total annual uptake (kg ha-1) was 137.3, 10.4, 51.1, 5.5, 8.7 and 18.2 for N, P, K, Na, Ca and Mg, respectively. In an annual cycle 98% N, 77% P, 49% K, 109% Na, 87% Ca and 65% Mg returned to the soil through litter and belowground detritus. A major portion of N, P and Na was recycled through the belowground system, whereas nearly half of K, Ca and Mg was recycled through the shoot system. Precipitation acts as the source of N and P input, but at the same time causes loss of cations.
TL;DR: Algae was clearly shown to be a superior food resource for Cloeon sp.
Abstract: Early instar nymphs of the mayfly, Cloeon sp. were kept on an algal or a detrital diet at 20 ± 1 °C in the laboratory. A control group was not given any food. Nymphs kept on algae showed significantly (P = 0.001) higher growth both in terms of length and biomass than for those kept on detritus. None of the nymphs given algae or detritus died during the experiment, and 40 per cent of those fed algae and 20 per cent fed detritus reached maturity by the termination of the experiment. Food retention time as well as gill ventilation rate of nymphs feeding on algae were significantly (P = 0.001) higher than those feeding on detritus. It is probable that these two factors largely enabled the nymphs to survive as well as to grow and reach maturity, though relatively slowly, solely on a detrital diet. However, algae was clearly shown to be a superior food resource for Cloeon sp. nymphs.
TL;DR: The synthesis of mixed-ligand fluoro complexes of UO22+ of the types A3[UO2(GlyH)2F5] · 3H2O [A = K (1) or NH4+ (2)], K3 [UO 2(AlanH) 2F5 · 2H 2O (3), (NH4)5[U O2(CysH), 2F 5]· 2 H 2 O (4), NH 4+ (5) as discussed by the authors, and [U O 2(
TL;DR: In this article, the photo-induced transient superconductivity in some cuprate systems which are otherwise in a semiconducting or insulating state are explained on the basis of a theoretical model which was suggested by us over two and a half decades ago.
Abstract: Recent observations of photo-induced transient superconductivity in some cuprate systems which are otherwise in a semiconducting or insulating state are explained on the basis of a theoretical model which was suggested by us over two and a half decades ago. In these systems, the radiation field quanta play a dual role. In the first they produce carriers and in the second role they take part in the pairing process along with virtual exchange of other boson modes, i.e. phonons or electronic boson modes. Owing to the two-boson nature the coupling constant λrb depends on the photon density (photoexcitations) impressed on the system. The relative role of the photoresponse time and the relaxation (recombination) time are important in producing the metallic and superconducting state.
TL;DR: In this article, the synthesis and characterization of some penta-coordinated ruthenium(II) complexes, viz. [RuX2(MPh3)(C4H3OCHO)2] (X � Cl or Br; M P or As), [RuBr2 (MPh 3)(C6H5CHO) 2] (M ǫ p or As) and [RuBR2(CO)(PPh3)2], are described.
TL;DR: It is suggested that glutamine synthetase serves as the sole ammonia-assimilating enzyme as well as glutamine-forming route in heterocystous cyanobacteria.
Abstract: The uptake of arginine and proline and their assimilation as nitrogen source have been studied in the cyanobacterium Anabaena cycadeae and its glutamine auxotropic mutant lacking glutamine synthetase activity. The uptake pattern of arginine and proline was found to be biphasic in both wild-type and mutant strains, consisting of an initial fast phase lasting up to 60 s followed by a slower second phase. The uptake activities of both the amino acids were also found to be similar in both the strains. The wild-type strain, having normal glutamine synthetase activity, utilized arginine and proline as sole nitrogen source, whereas the mutant strain lacking glutamine synthetase activity could not do so. These results suggest that: (1) glutamine synthetase activity is necessarily required for the assimilation of arginine and proline as nitrogen source, but it is not required for the uptake of these amino acids; and (2) glutamine synthetase serves as the sole ammonia-assimilating enzyme as well as glutamine-forming route in heterocystous cyanobacteria.
TL;DR: In this article, lead doped Bi 2 Sr 2 CaCu 2 O 8 (Bi 2212 ) single crystals were grown and their structures were studied by several methods, especially by resistivity measurements, electron microprobe and Raman micro-spectroscopy.
TL;DR: In this paper, the fusion-fission of 238 U and 209 Bi in different SSNTDs has been studied using 4 π-geometry technique and it has been shown that the projectile ions on interaction with the atoms of the detector media form compound nuclei and subsequently scission of the compound nucleus takes place in the forward hemisphere.
TL;DR: In this article, a probabilistic method based on the signal-to-noise ratio is employed to obtain a simple recursion relation for the zero temperature as well as the finite temperature dynamics of the network.
Abstract: We present an analysis of the parallel dynamics of the Hopfield model of the associative memory of a neural network without recourse to the replica formalism. A probabilistic method based on the signal-to-noise ratio is employed to obtain a simple recursion relation for the zero temperature as well as the finite temperature dynamics of the network. The fixed points of the recursion relation and their basins of attraction are found to be in fairly satisfactory agreement with the numerical simulations of the model. We also present some new numerical results which support our recursion relation and throw light on the nature of the ensemble of the network states which are optimized with respect to single spin flips.