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  • 1
    Electronic Resource
    Electronic Resource
    Massive configurations with constant densities (1982)
    Springer
    Astrophysics and space science 88 (1982), S. 469-475 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Two new classes of solutions with constant observed proper and rest mass densities are described. Unlike the well-known solution of constant coordinate mass density, these solutions pertain to realistic physical situations. For these solutions, the various relevant parameters, viz. the redshifts (dP/dρ)0 and binding coefficients have been calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01092712
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  • 2
    Electronic Resource
    Electronic Resource
    Polytropic spheres with isothermal cores (1983)
    Springer
    Astrophysics and space science 90 (1983), S. 139-145 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The paper deals with massive fluid spheres with an isothermal core (having finite central density) and a polytropic envelope in terms of the General Relativity. The matching of the solutions in the core and envelope has been done using Bondi's condition,H=0 and also without it. The study reveals that since this condition does not correspond to any particular physical situation the maximum values of fractional core size, fractional core mass and the redshift do not occur atH=0, but that they occur at some other point. Within the permissible physical conditions (dP/dρ≤1) the maximum values ofM core/M,R core/R and the surface redshift, for an isothermal coreP=ρ/3, are respectively 0.473, 0.554, and 0.565. Using the conditionH=0, it has been shown that for isothermal cores corresponding to the equation of the stateP≥0.6ρ, the configurations are pulsationally unstable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651554
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  • 3
    Electronic Resource
    Electronic Resource
    Stigmatic secretion and bud-pollinations in self- and cross-incompatible plants (1963)
    Springer
    Naturwissenschaften 50 (1963), S. 408-409 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01178615
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  • 4
    Electronic Resource
    Electronic Resource
    Thermal behaviour of polyetherimide peek blends (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 143-147 
    Details
    ISSN: 1572-8943
    Keywords: polyetherimide peek blends
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract PEEK is characterised by high impact and fatigue resistance andT g of 145
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01987432
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal analysis on influence of compatibilizing agents (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 281-292 
    Details
    ISSN: 1572-8943
    Keywords: compatibilization ; elastomer blend ; phase morphology ; thermal analysis ; ultrasonic velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Studies have been made on differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and dynamic mechanical analysis (DMA) of binary blends of isobutylene-isoprene (IIR) copolymer and polychloroprene (CR) elastomers. Blends of IIR and CR are incompatible and showed separateT g peaks in DSC curves similar to Tanδ peaks. However, addition of chlorinated polyethylene (CM) elastomer, as compatibilizer, imparts miscibility between IIR and CR which could be judged both through DSC as well as by dynamic loss measurements (Loss modulusE″ and Tanδ). The storage modulus (E′) showed variation of stiffness due to structural changes associated with the addition of compatibilizer. TG plots for these blends showed improvement of thermal stability both by addition of a suitable compatibilizer as well as due to formation of crosslinked structures associated with the vulcanization of the blends by standard curative package.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01987449
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  • 6
    Electronic Resource
    Electronic Resource
    Trajectories of zero rest-mass particles and gravitational trapping in interior geometries (1991)
    Springer
    Astrophysics and space science 176 (1991), S. 131-140 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Trajectories of zero rest-mass particles (ZRP) are quite well studied in Schwarzschild geometry but not in interior geometries. In this paper the trajectories of ZRP have been obtained and discussed for Tolman's IV solution. It is found that the inward moving ZRP approaches the centre up to a minimum distance and then draws away from it if the angle of emittance is less than that for the ‘cone of avoidance’. If, however, the angle of emittance is greater than the angle of ‘cone of avoidance’, the ZRP moves inwards up to a certain minimum distance from the centre and then stays at this distance in a circular orbit. In this regard four different kinds of orbits have been identified. Calculations have also been done for the number of ZRP that will escape such massive configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00643083
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  • 7
    Electronic Resource
    Electronic Resource
    A fluorescence spectroscopic study on wood (1998)
    Springer
    Wood science and technology 32 (1998), S. 309-315 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Fluorescence spectroscopy has been suggested as an important tool for identification of timber (Krishna, Chowdhury 1935; Dyer 1988; Sum et al. 1991). In the present study measurements of fluorescence excitation and emission spectra from solid wood blocks, powder and their extract in methanol from heartwood ofAcacia nilotica (Babul),Albizia lebbek (Kokko),Pterocarpus marsupium (Bijasal),Toona ciliata (Toon),Tectona grandis (Teak) andEucalyptus tereticornis (Eucalypt) have been made. Fluorescence spectra obtained from solid dry wood is independent of excitation wavelength, whereas those obtained from extracts exhibited excitation wavelength dependence indicating presence of many fluorescent chemicals. The need for systematic study of wood extracts in different polar and nonpolar solvents, which would be useful for purposes of identification of wood species, is stressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702898
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  • 8
    Electronic Resource
    Electronic Resource
    Genetic transformation and “graft-hybridization” in flowering plants (1976)
    Springer
    Theoretical and applied genetics 47 (1976), S. 299-302 
    Details
    ISSN: 1432-2242
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Recent pollination experiments with highly irradiated (100,000 r) pollen in Nicotiana have shown that radiation-“pulverized” pollen chromatin can cause genetic transformation of the egg. A new model is proposed here for integration of chromatin fragments into host chromosomes. It is also proposed that heterochromatin may be involved in the process of gene transfer, and in the phenomena of meiotic drive associated with gene transfer. It is suggested that this discovery throws new light on the phenomenon of “graft-hybridization”. In spite of many reports to the contrary, “graft-hybrids” have so far been explained only on the basis of their being chimaeras. A mechanism is suggested here by which they may result from genetic transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00281935
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  • 9
    Electronic Resource
    Electronic Resource
    Origin of complementary incompatibility systems in flowering plants (1977)
    Springer
    Theoretical and applied genetics 49 (1977), S. 101-109 
    Details
    ISSN: 1432-2242
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The complementary incompatibility system, characterized by co-operative control of a single S specificity by alleles of two or more distinct S genes, has raised interesting questions regarding the origin and evolutionary significance of this system. What were the factors which led to the appearance of the complementary system of self-incompatibility. Is complementary incompatibility a primary or secondary development? Lundqvist and Østerbye have suggested that the fundamental characteristic of this system — lack of dominance and competitive interactions between alleles of the same and different series — developed once, early in the evolution of angiosperms, at a stage when self-incompatibility was controlled polygenically. In one line of development, where two or more such incompatibility genes were strengthened by specific modifiers at the expense of the rest, co-operation among loci was favoured to promote increased interplant compatibility in the population. In this evolutionary line, allelic or intergenic interactions were excluded. In the other line of development, where only one incompatibility locus was strengthened, there was no need for such selection and alleles of this locus retained the property of allelic interaction in the pollen. In this article an alternative hypothesis has been proposed for the origin of complementary incompatibility. It is suggested that this type of incompatibility system, conforming with generally held views on the evolution of self-incompatibility systems, developed secondarily, and polyphyletically, after the breakdown of the original one-locus, multiallelic, gametophytic system. In the re-revolution of self-incompatibility through introgression with a related self-incompatible taxon, the essential action of the presumed physiologically integrated self-compatible complex led to the exclusion of allelic or intergenic interaction as a prerequisite for evolution of complementary control. According to this hypothesis, breakdown of the original self-incompatibility and re-evolution of self-incompatibility, in the manner suggested above, could have occurred many times in the evolution of angiosperms and such systems might therefore be expected to occur scattered among different phylogenetic lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00281707
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  • 10
    Electronic Resource
    Electronic Resource
    Evolution of incompatibility systems in plants: Complementarity and the mating locus in flowering plants and fungi (1977)
    Springer
    Theoretical and applied genetics 50 (1977), S. 89-101 
    Details
    ISSN: 1432-2242
    Keywords: Incompatibility ; Evolution ; Flowering Plants ; Fungi ; Complementarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The restriction of sexual pairing by a specificity gene is considered to be an ancient development in the plant kingdom. The diversity and general parallelism of incompatibility systems seen amongst the phyla at the present time can be rationalized in terms of the association of various derived forms of the ancestral specificity unit with differing spectra of accessory factors controlling sexual physiology in the different phyla. Sexual morphogenesis has become divided into distinct phases under the control of complementary genes. These phases are initiated by a regulatory system of “Co-ordinator genes” which control the order in which groups of morphogenetic genes are expressed during development. The entire sexual cycle will be completed only if all the complementary groups are activated in the appropriate sequence. The present article discusses essential features of the evolution of the breeding locus in different phyla. These features are consistent in themselves with the present data and are not dependent on the proposed ancient origin of the specificity gene. The above hypothesis throws light on the (1) evolution of the complex mating loci in flowering plants and fungi; (2) evolution of complementary incompatibility and heteromorphic incompatibility in flowering plants; (3) anomalous cross-compatibility behaviour of mutants in the fungus Schizophyllum commune; (4) nature of homothallism in higher fungi; (5) mode of origin of new functional self-incompatibility alleles; and (6) “homogenic” and “heterogenic” incompatibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00277251
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