Browsing by Author "R. Shyam"

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Behaviour of a discontinuity at the wave-head propagating through a relaxing gas
(Springer-Verlag, 1982) J. Sharma; R. Shyam; V.D. Sharma
The rate of amplification of a discontinuity in the velocity gradient is evaluated at the wave-head in a spatially uniform but time evolving flow of a relaxing gas. The paper investigates the effects of relaxation (present in the flow) and the initial wave front curvature on the growth and decay behaviour of waves in the thermodynamical state of weak or strong equilibrium. © 1982 Springer-Verlag.
Distorted wave analysis of (d,p) reactions to decaying states
(1977) S.N. Mukherjee; R. Shyam; S. Pal; N.K. Ganguly
The distorted-wave Born approximation is used in the case of the stripping reaction S32(d,p)S*33 leading to decaying states in order to explain the strong dependence of the ratio of the energy differential (d,p) stripping cross section to the total neutron elastic scattering cross section on the same target, on transferred angular momentum (l) The necessity of using a distorted-waves approximation instead of a plane-waves approximation, which is much simpler to calculate and which also shows " l dependence," is discussed in the context of identification of levels. The slowly converging overlap integral appearing in the distorted-wave Born approximation is treated by employing a Gaussian convergence factor. It is also found that in the plane-wave calculation, the inclusion of the unscattered part in the neutron form factor affects only the l=0 resonances. The desirability of including the effect of the nuclear interior is discussed. The angular distribution for the reaction O6(d,p)O*17 has been obtained employing the distorted-wave Born approximation method. The spectroscopic factor for this reaction is obtained and compared with that reported previously. NUCLEAR REACTIONS S32(d,p), O16(d,p) reactions, unbound states, calculated [d2σ(d,p)]dΩdE, [dσ(d,p)]dΩ, ED=12-13.3 MeV, DWBA analysis. © 1977 The American Physical Society.
Effect of colchicine, maleic hydrazide, caffeine and theobromine on cell division of the algal flagellate Gymnodinium inversum var. elongatum Nygaard (Dinophyceae)
(1975) Y.S.R.K. Sarma; R. Shyam
[No abstract available]
Effects of colchicine on the cell division of a colonial green algal flagellate gonium pectorale muller
(1976) R. Shyam; Y.S.R.K. Sarma
The effects of colchicine on a colonial algal flagellate Gonium pectorale (Volvocales, Chlorophyceae) are recorded for the first time. While, lower concentrations up to 0.5% of colchicine do not produce any effects, 1.0% concentration of this alkaloid brings about contraction of chromosomes, accumulation of metaphase plates, polyploid nuclei, multinucleate cells and cell enlargement. At this concentration, increase in chromosome number is the outstanding effect, such increases ranging from partial doubling, to diploidy and tetraploidy. In none of the cases all the cells of colony seem to have been affected, since unaffected cells within the same colony showing normal chromosome number have been observed. The affected cells generally are observed not to divide further instead, they died. © 1976 Taylor and Francis Group, LLC.
Lundiella indica gen, et sp. Nov., a new member of colonial volvocales (chlorophyceae) from india
(1974) Y.S.R.K. Sarma; R. Shyam
A new alga designated as Lundiella indica gen. et sp. nov. is described from India. It is at present known only in vegetative condition. It clearly belongs in the colonial Volvocales but its features of vegetative morphology do not agree with those of any known genus of this order. © 1974 Taylor & Francis Group, LLC.
Observations on the morphology, reproduction and cytology of stigeoclonium pascheri (vischer) cox et bold (chaetophorales-chlorophyceae) and their bearing on the validity of the genus caespitella vischer
(Kluwer Academic Publishers, 1980) R. Shyam; Y.S.R.K. Sarma
The present communication deals with the morphology, reproduction and cytology of Stigeoclonium pascheri (formerly described as Caespitella pascheri Vischer). Effects of various concentrations of nitrate and variations in intensity and duration of light period in 24 hr LD cycles were studied on cultures of this alga in relation to the type and extent of branching and occurrence or absence of hair formation. It is concluded that these traits are not of taxonomic significance and are influenced largely by environmental conditions. The present study shows a large overlapping of morphological characters between the genera Stigeoclonium and Caespitella and supports Cox & Bold's abandonment of the latter generic name and its merger into the genus Stigeoclonium. The chromosome number determined for this alga is n = 6 which indicates that the Indian strain of this alga is a distinct cytotype from the one originally isolated by Vischer. © 1980 Dr. W. Junk b.v. Publishers.
On the morphology, reproduction and cytology of two new freshwater dinoflagellates from india
(1974) Y.S.R.K. Sarma; R. Shyam
The morphology, reproduction and cytology of two new species of Gymnodinium (G. dodgei and G. lalitae) are described, as also are morphological variations encountered in natural populations and cultures. Chromosome numbers determined for these two new taxa are: G. dodgei, 195 ± 5; G. lalitae, 90±4. Some systematic aspects of the genus Gymnodinium and the process of encystment in G. dodgei are discussed. © 1974 Taylor & Francis Group, LLC.
Slowly converging integrals in the analysis of deuteron stripping to decaying states
(1978) S.N. Mukherjee; R. Shyam; S. Pal; N.K. Ganguly
The slowly converging overlap integral appearing in the distorted wave Born approximation analysis of deuteron stripping to decaying states is treated by employing a Gaussian convergence factor to ensure proper convergence. Numerical results are presented and the usefulness of the above technique in handling stripping overlap integrals in the continuum region is discussed. NUCLEAR REACTIONS S32(d, p) reactions, unbound state, calculated σ(Ep, θp), ED=12.0 MeV, method of handling the divergent integrals discussed. © 1978 The American Physical Society.
Studies on north indian volvocales-III. Fertilization in Eudorina californica (shaw) goldstein
(Kluwer Academic Publishers, 1976) R. Shyam; Y.S.R.K. Sarma
The present communication deals with the details of sexual reproduction including the process of fusion of gametes in Eudorina californica (Shaw) Goldstein (earlier described as E. indica lyengar). The present observations are compared with those on other species in which the process of fusion was recorded. © 1976 Dr. W. Junk b. v. Publishers.
Synthesis of some new benzothiazolylguanidines and their activities
(1979) P.N. Bhargava; I.C. Tiwari; R. Shyam
[No abstract available]
Woloszynskia stoschii and Gymnodinium indicum, two new freshwater dinoflagellates from India: Morphology, reproduction and cytology
(Springer-Verlag, 1975) R. Shyam; Y.S.R.K. Sarma
The distinctive morphological and karyological features of the two new species, collected from freshwater habitats in North India, are presented and compared with those of related taxa of the genera Woloszynskia and Gymnodinium. Asexual reproduction takes place through zoospore formation and sexual reproduction through planozygotes in Woloszynskia stoschii. © 1975 Springer-Verlag.