Showing papers by "Banaras Hindu University published in 1984"
TL;DR: The regeneration status of certain tree components of forests in the northwestern catchment of the river Gola in Kumaun Himalaya is dealt with and possible compositional changes in time are explored.
Abstract: This study deals with the regeneration status of certain tree components of forests in the northwestern catchment of the river Gola in Kumaun Himalaya and explores possible compositional changes in time.Pinus roxburghii, Quercus floribunda andQuercus lanuginosa in their respective forest types had a stable population structure with a large percentage of young individuals (seedlings) and relatively few old ones, indicating that these species are frequent reproducers. The girth class distribution of the individuals ofQuercus leucotrichophora in theQuercus leucotrichophora forest suggests that this species is likely to disappear gradually. In this forest, although forest composition will remain unchanged for some time, a complete absence of seedlings of any species shows the possibility of its complete replacement by a scrub or a grassland vegetation. In the mixed forest, the dominant species, viz.,Quercus leucotrichophora, Persea odoratissima andBauhinia retusa did not have saplings/seedlings, indicating a possible change in forest composition in the near future whenSapium insigne, Cocculus laurifolius, Celtis eriocarpa andAcer oblongum are likely to gain dominance. Finally, suggestions are made to explain the poor regeneration ofQuercus leucotrichophora.
182 citations
TL;DR: In this article, a novel expression for the Gibbs free energy change (ΔG) accompanying crystallisation of an undercooled melt is developed based on the hole theory of liquids and is capable of reproducing the temperature dependence of ΔG in case of pure metals, glass forming alloys and organic liquids.
132 citations
TL;DR: In this paper, the free-convection flow of an incompressible and viscous fluid past an exponentially accelerated infinite vertical plate is analyzed using the Laplace transform method.
Abstract: The free-convection flow of an incompressible and viscous fluid past an exponentially accelerated infinite vertical plate is analysed. The Laplace transform method is used to obtain the expressions for velocity and skin-friction. The effect of various parameters, occuring into the problem, is discussed with the help of graphs and table.
78 citations
TL;DR: In this paper, the effects of Hall current and rotation on the flow of electrically conducting rarefied gas due to combined buoyant effects of thermal and mass diffusion, past an infinite porous plate in the presence of transverse magnetic have been investigated.
Abstract: Effects of Hall current and rotation on the flow of electrically conducting rarefied gas due to combined buoyant effects of thermal and mass diffusion, past an infinite porous plate in the presence of transverse magnetic have been investigated. The equations governing the flow problem have been solved and the profiles are shown on graphs. Effects ofm (Hall parameter) andE (Ekman number) on velocity are discussed.
58 citations
TL;DR: Over part of the surface of the pelvic fins and the distal parts of the rays of the pectoral fins, the skin contains no goblet cells and bears a thick external secretion, or cuticle, containing protein and glycoprotein which is mainly neutral in reaction, although some cells at the edges of the region secrete weakly sulphated or non-sulphated acidic glycoproteins.
Abstract: Mucus is secreted to the surface of the body and fin webs of Blennius pholis by superficial epithelial cells and by goblet cells. Some goblet cells secrete sulphated acid glycoproteins, others produce a mucus which is neutral or mixed in its reactions. The superficial epithelial cells of these areas secrete sulphated acid glycoproteins, seen by electron microscopy as electron-lucent or moderately lucent vesicles; this secretion is not normally visible external to the skin in transmission electron microscope (TEM) sections. These cells do not react to the bromphenol blue test for proteins. Over part of the surface of the pelvic fins and the distal parts of the rays of the pectoral fins, the skin contains no goblet cells and bears a thick external secretion, or cuticle, containing protein and glycoprotein which is mainly neutral in reaction, although some cells at the edges of the region secrete weakly sulphated or non-sulphated acidic glycoprotein. The protein content of the columnar superficial epithelial cells of these regions correlates with the fibrous nature of the secreted cuticular layer as seen by TEM; the columnar cells are characterized by extensive ribosomal endoplasmic reticulum and vesicles which stain darkly with phosphotungstic acid, less so with uranyl acetate. The distal part of the cell, containing these vesicles, reacts positively to the PAS stain. In some places the borders of the zones with fibrous cuticle are characterized by cuboidal superficial epithelial cells which give a strong positive reaction to alcian blue at pH 1.0, indicating the presence of sulphated acid glycoproteins, but also react positively to the bromphenol blue test for proteins.
54 citations
TL;DR: The results indicate that the male-originating pheromone involved in the Bruce effect is nonvolatile and acts on the females through contact, whereas the Whitten effect was induced in unisexually grouped females by exposure to corralled males.
Abstract: Experiments were designed to elucidate the mode of transmission of the male-originating pheromones involved in the induction of estrus (the Whitten effect) and in implantation failure (the Bruce effect) in mice. The Whitten effect was induced in unisexually grouped females by exposure to corralled males, and also by corralled males housed within a perforated cage (which prevented physical contact of the females with the male-originating pheromone). The results suggest that the pheromone involved in the Whitten effect is volatile (airborne). Implantation failure occurred in a significantly high proportion of newly inseminated females when they were individually confined in corrals and housed below corralled alien males. By contrast, implantation failure was significantly reduced when corralled females were housed above corralled alien males. The results indicate that the male-originating pheromone involved in the Bruce effect is nonvolatile and acts on the females through contact. It is suggested that the pheromone involved in the Whitten effect is distinct from the one involved in the Bruce effect.
49 citations
TL;DR: In this article, the distribution, methods of isolation and structure elucidation of flavans, by comprehensive spectral analyses, are presented, and biological properties of flavants are appraised.
41 citations
TL;DR: In this paper, the ability of the alkaloidal constituents to complex with divalent metal ions and phytosterols has been examined with a view to evaluating their significance in plant biochemistry.
39 citations
TL;DR: In this article, a metastable Al-Zr alloy with an ordered cubic Cu3Au-type structure with a = 0.4073 nm and at a later stage the equilibrium Al3Zr phase having a tetragonal structure with 0.4013 nm and c = 1.7321 nm.
38 citations
TL;DR: The available data on the age-associated alterations in the composition, structure and function of chromatin have been discussed, and an attempt has been made to correlate the structural changes in chromatin with alteration in gene expression during aging.
35 citations
TL;DR: In this article, the authors studied the 2H-3C transformation in ZnS crystals and found that the stacking faults involved in the transformation are basal plane deformation faults, and that the resulting 3C structure invariably contains a random distribution of twin faults.
Abstract: X-ray diffraction of the 2H-3C transformation in ZnS crystals has been studied to determine the mechanism of the phase transformation. Single crystals of 2H ZnS were annealed in vacuum at different temperatures to induce the phase transformation and then quenched to arrest it at different intermediate stages. The transformation is found to occur by the non-random nucleation of stacking faults in the 2H structure which produce characteristic diffuse steaks along reciprocal lattice rows parallel toc* for whichH−K ≠ 0 (mod 3). All the crystals finally transform to a disordered twinned 3C structure. A study of the broadening of the x-ray diffraction maxima reveals that the stacking faults involved in the transformation are basal plane deformation faults. Initially these nucleate at random producing a random distribution of cubic nuclei within the 2H structure. As the transformation proceeds these 3C nuclei grow into thick 3C regions by a preferential nucleation of the faults at 2-layer separations. Since the 3C nuclei can have twin orientations the resulting 3C structure invariably contains a random distribution of twin faults. This is confirmed by comparing the experimentally observed intensity profile of the 10.L reflections as recorded on a single crystal diffractometer, with those calculated theoretically for a randomly twinned cubic structure.
TL;DR: Observations on autoradiographic labelling of partially lysed polytene chromosomes provide evidence for a lack of temporal and spatial agreement in the activation of origin points in homologous regions of the lateralPolytene strands; these observations also suggest local variations in levels of polyteny within a chromosome.
Abstract: It is widely known that the bulk of the pericentromeric heterochromatin (α-heterochromatin) does not replicate during polytenization in Drosophila. However, a recent DNA-Feulgen cytophotometric study (Dennhofer 1982a) has claimed equal polytenization of all heterochromatin regions. To re-examine this issue, the amount of Hoechst 33258-bright heterochromatin in non-polytene and polytene nuclei in salivary glands and Malpighian tubules of late third instar larvae of D. nasuta has been compared by cytofluorometry. Since the amount of Hoechst 33258-bright heterochromatin is similar in non-polytene and polytene nuclei in spite of the latter having an enormously high euchromatin DNA content, it is concluded that the α-heterochromatin does not replicate during polytenization. The present results further indicate that in the polytene nuclei of Malpighian tubules the α-heterochromatin remains at the 2C level whereas in salivary gland polytene nuclei it varies between the 2C and 4C levels.
TL;DR: In this article, withanolides, withaperuvin E and nicandrin B, isolated from Physalis peruviana and Nicandra physaloides, were fully characterized by chemical and spectroscopic means.
TL;DR: In this article, Raychaudhuri-type equations are written for a cosmological model filled with perfect fluid and obeying the equations of a self-creation theory recently proposed by G. A. Barber.
Abstract: Raychaudhuri-type equations are written for a cosmological model filled with perfect fluid and obeying the equations of a self-creation theory recently proposed by G. A. Barber. In addition some general results on spatially homogeneous cosmological models are obtained. The Hawking-Penrose energy condition suggests that the singularity can be avoided in this theory.
TL;DR: In this article, the three dimensional flow of a viscous incompressible and electrically conducting fluid past an infinite vertical plate started impulsively in its own plane is discussed in a rotating system.
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TL;DR: Metallic glasses are a new class of materials produced by rapidly quenching the melts at rates often exceeding a million deg/sec as mentioned in this paper, and have been found to display an optimum combination of properties such as high strength, good bend ductility, improved corrosion resistance and excellent soft magnetic properties.
Abstract: Metallic glasses are a new class of materials produced by rapidly quenching the melts at rates often exceeding a million deg/sec. These have been found to display an optimum combination of properties such as high strength, good bend ductility, improved corrosion resistance and excellent soft magnetic properties. Thus, metallic glasses are emerging as economically viable competitors to conventional engineering materials.
TL;DR: In this article, the three-dimensional flow of an electrically conducting and incompressible viscous fluid past a uniformly accelerated infinite vertical porous plate is studied in a rotating fluid.
Abstract: The three-dimensional flow of an electrically conducting and incompressible viscous fluid past a uniformly accelerated infinite vertical porous plate is studied in a rotating fluid. The flow is assumed to be at small magnetic Reynolds number so that the induced magnetic field is neglected. An exact solution has been obtained by defining a complex velocity with the help of the Laplace transform method for the Prandtl number equal to unity. The effects of rotation, magnetic and free-convection parameters are discussed for the whole problem. Also, the skin-friction components on the plate are discussed.
01 Aug 1984-Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. 1. Abt. Originale. A, Medizinische Mikrobiologie, Infektionskrankheiten und Parasitologie
TL;DR: Five of 16 strains of Plesiomonas shigelloides freshly isolated from children with acute diarrhoea, exhibited invasiveness for HeLa cells comparable to that of Shigella sonnei; however, none of the five gave a positive reaction in the Sereny test.
TL;DR: The glass forming composition range in several binary metallic systems is correlated with the composition dependence of S cc (0), the concentration-concentration fluctuation structure factor at its long wavelength limit as mentioned in this paper.
Abstract: The glass forming composition range in several binary metallic systems is correlated with the composition dependence of S cc (0), the concentration-concentration fluctuation structure factor at its long wavelength limit. The magnitude of S cc (0) has been evaluated for the liquid phase from available thermodynamic data. It has been observed that S cc (0) exhibits a maximum and tends to the ideal value in the glass forming composition range. Significant and systematic negative deviations from ideal values or the tending to zero of S cc (0) are observed at the stoichiometry corresponding to complexes in the liquid state in the case of compound forming or associated systems. These observations are discussed in terms of the chemical short-range order in the liquid state. It is concluded that while a reasonable degree of order may exist for the compound forming compositions, in the glass forming region itself the liquids are nearly random mixtures of complexes and unassociated component atoms.
TL;DR: While thyroid hormone, acting by way of the hypothalamo-hypophysial complex and/or by direct action on the feather papillae, modulates the annual cycles of plumage pigmentation, bill color, gonad development, and body weight of lal munia, the finch has an endogenous mechanism which enables it to adapt to chronic hyperthyroidism in such a way that breeding occurs at the normal time of the year.
TL;DR: In this article, the effect of Hall currents on the hydromagnetic free-convection flow of an electrically conducting and incompressible viscous fluid past a uniformly accelerated infinite vertical porous plate is discussed.
Abstract: The effect of Hall currents on the hydromagnetic free-convection flow of an electrically conducting and incompressible viscous fluid past a uniformly accelerated infinite vertical porous plate is discussed The magnetic Reynolds number is assumed to be small so that the induced magnetic field can be neglected The governing equations of the flow are solved by defining a complex velocity with the help of the Laplace transform method when the Prandtl number is equal to unity The influence of the various parameters on the unsteady flow field is presented for both the cases, cooling and heating of the porous plate by free-convection currents
TL;DR: An alternative definition of a fuzzy Sierpinski space is given and its appropriateness is established.
TL;DR: In this article, the effect of heat sinks on the free-convection flow of an incompressible viscous fluid past an impulsively started infinite vertical porous plate is considered.
Abstract: The effect of heat sinks on the free-convection flow of an incompressible viscous fluid past an impulsively started infinite vertical porous plate is considered. Finite difference method has been used to obtain the numerical solution of the governing equations. The influence of the various parameters, occurring into the problem, on the velocity field, the temperature field and on their related quantities is extensively discussed with the help of graphs and tables.
TL;DR: Field grown rice plants exposed separately to 0.25 or 0.5 ppm SO2 for 1.5 hr daily for 40 days showed significant decrease of catalase and increase of peroxidase activities as well as decreases of protein and ascorbic acid contents associated with leaf lesions, which were proportional to SO2-dose.
Abstract: Field grown rice (Oryza sativa L.) plants exposed separately to 0.25 or 0.5 ppm SO2 for 1.5 hr daily for 40 days, showed significant decrease of catalase (p < 0.001) and increase of peroxidase (p < 0.001) activities as well as decreases of protein (p < 0.001) and ascorbic acid (p < 0.001) contents associated with leaf lesions, which were proportional to SO2-dose. Catalase and peroxidase activity levels showed an inverse relationship. It is hypothesized from the molecular structure of both enzymes and from the in vitro relationship between catalase and peroxidase activity that the tetrameric molecules of catalase in vivo might disintegrate into monomeric units with peroxidase activity, which in turn oxidise ascorbic acid and may reduce tolerance of plants to SO2.
TL;DR: It is proposed that certain temperature-dependent enzyme(s) associated with DNA replication kinetics may be involved in the formation of SCEs.
Abstract: The incidence of sister chromatid exchanges (SCEs) and cell proliferation kinetics have been studied in peripheral blood lymphocytes of man and muntjac grown at 33 to 44 °C to gain insight into SCE formation The frequency of SCEs increased as a function of growth temperature At a given temperature, however, the frequency of SCEs varied with the sampling times; the early sampled cells showed fewer SCEs than did those harvested late At 33 °C the frequency of SCEs was lowest and there was a marked delay in cell-cycle progression The number of SCEs was maximum at 40 °C in human and 42 °C in muntjac Cell proliferation was markedly affected at higher temperature and 44 °C was found to be intolerable for lymphocytes of both the species It is proposed that certain temperature-dependent enzyme(s) associated with DNA replication kinetics may be involved in the formation of SCEs
TL;DR: It is suggested that the influence of any one of the hormones utilized in the present study on blood morphology of fasted snakes depends to a greater extent on the presence or absence of the other hormone(s).
TL;DR: In this paper, the effects of Hall current on free convection and mass transfer flow through a porous medium bounded by a vertical surface has been analyzed and the velocity profiles are shown on graphs.
Abstract: Effects of Hall current on free convection and mass transfer flow through a porous medium bounded by a vertical surface has been analysed The problem is solved analytically The velocity profiles are shown on graphs Effects ofm (Hall parameter)K* (permeability parameter), and Sc (Schmidt number) on velocity are discussed
TL;DR: In this article, the complex-lamellar motion and Beltrami flow of steady rotating magneto fluids are discussed and some results of physical importance are derived using anholonomic geometric results.
Abstract: Employing the anholonomic geometric results, the complex-lamellar motion and Beltrami flow of steady rotating magneto fluids are discussed and some results of physical importance are derived.