Showing papers by "Royal Holloway, University of London published in 1973"
TL;DR: In this article, a general theory is developed that leads to a simple criterion for the existence of a perfect code in a distance-transitive graph, and it is shown that this criterion implies Lloyd's theorem in the classical case.
243 citations
[...]
TL;DR: In this paper, it was shown that there are no Moore graphs of diameter ≥ 3, other than polygons, and that the only possible Moore graphs are the following ones, i.e.,
Abstract: In this paper, we shall first describe the theory of distance-regular graphs and then apply it to the classification of Moore graphs. The object of the paper is to prove that there are no Moore graphs (other than polygons) of diameter ≥ 3. An independent proof of this result has been given by Barmai and Ito(1). Taken with the result of (4), this shows that the only possible Moore graphs are the following:
192 citations
TL;DR: In this article, the major carbohydrate of low molecular weight in brown seaweeds named in the title, Mannitol, was detected in Bifurcaria, and glucose and myo-inositol were detected in Himanthalia.
98 citations
89 citations
TL;DR: An energy budget is presented for adult Brachionus plicatilis Muller, a brackish water rotifer, and Ecological efficiencies are calculated and discussed in relation to those of animals of similar feeding habits.
Abstract: An energy budget is presented for adultBrachionus plicatilis Muller, a brackish water rotifer. At 20°C the hourly consumption ofDunaliella salina by an individual rotifer was found to be 332.79±93.25 cal. The assimilation rate was 64.43±9.95 cal per hour when measured, and 62.88 cal per hour when calculated fromP+R. The difference between these two values is 2.4%. Respiration rate per individual per hour was 26.375±2.4 cal and egg production cost 36.5 cal per hour. The amount of faecal matter produced in an hour was obtaineb by subtraction (C-A). Ecological efficiencies are calculated and discussed in relation to those of animals of similar feeding habits.
88 citations
TL;DR: In this article, the force fields for the in-plane vibrations of benzene and its fluoro derivatives were determined using the overlay technique and convergence on the experimental frequencies was smooth and rapid.
84 citations
TL;DR: The number and duration of free-living and parasitic stages of N. dubius has been determined and the results have been discussed in relation to previous accounts of the life cycle, and some of the discrepancies explained.
Abstract: 1. The number and duration of free-living and parasitic stages of N. dubius has been determined. 2. The results have been discussed in relation to previous accounts of the life cycle, and some of the discrepancies explained.
70 citations
TL;DR: In this paper, a quadratic force field for the out-of-plane vibrations of florobenzenes was determined, and the present field is in excellent accord with the chlorobenzene field of Scherer and with the benzene fields of Whiffen and of Kydd when due allowance is made for differences in coordinate definitions.
68 citations
TL;DR: In this paper, a polarized orbital distorted wave model is used to calculate total and differential cross sections for 1s to ns(n=2,3,4,5) electron impact induced transitions in H and He+ from threshold to 20 Ryd.
Abstract: A polarized orbital distorted wave model is used to calculate total and differential cross sections for 1s to ns(n=2,3,4,5) electron impact induced transitions in H and He+ from threshold to 20 Ryd. The total cross sections for the 1s to 2s transitions are in good agreement with experiment, but cannot in this model show resonances. The differential cross sections at energies above 100 eV agree closely with those of Geltman and Hidalgo (1971). The model reduces to the Born-Oppenheimer (z=0) or CBO I(z=0) when the polarization and static potentials are omitted.
59 citations
TL;DR: In this paper, the mixing process NaCl+KCl →(Na, K)Cl in the liquid state at T=1083 K and zero pressure is simulated by means of Monte Carlo calculations.
Abstract: The mixing process NaCl+KCl →(Na, K)Cl in the liquid state at T=1083 K and zero pressure is simulated by means of Monte Carlo calculations. A cubic box with periodic boundary conditions containing 216 ions interacting according to a pair potential of the Huggins-Mayer form served as a model of the system. Thermodynamic properties are calculated for the mixture and the pure salt models and compared with experiments. Radial and angular distribution functions are obtained. A perturbation theory of the heats of mixing of molten salts and the ‘random mixture approximation’ are commented on in the light of the Monte Carlo results.
56 citations
01 Jan 1973
TL;DR: Two late Cretaceous mammals from the Djadokhta Formation of Mongolia are described, known from two partial skulls and associated lower jaws, and Deltatheroides cretacicus, known only by the facial part of a skull with upper dentition.
Abstract: THE family Deltatheridiidae was proposed by Gregory and Simpson1 to include two late Cretaceous mammals from the Djadokhta Formation of Mongolia (? Coniacian or Santonian2): Deltatheridium pretrituberculare, known from two partial skulls and associated lower jaws, and Deltatheroides cretacicus, known only by the facial part of a skull with upper dentition. They were believed to occupy a very central phylogenetic position among the eutherian mammals. Van Valen3 included them in the Palaeoryctidae, order Deltatheridia, but one of us (P. M. B.)4 has for some time doubted the correctness of these opinions.
TL;DR: In this paper, partial hydrolysis studies proved the mutual linkage of the fucose (at C-3) and glucuronic acid, and the presence of an unidentified 6-deoxy sugar derivative which was also linked to glucurononic acid.
TL;DR: It is shown that nests may persist for well over a year, though the leaves of which they are made normally decay completely in a much shorter time, while most hedgehogs that died in their nests during winter were juveniles perhaps too inexperienced to construct an adequately protective nest.
Abstract: An account is given of the winter nests of the hedgehog (Erinaceus europaeus L.), and their importance in the life of this species. Nests were constructed for protection during hibernation, in sites chosen for the degree of support gained from surrounding objects. They were usually made mainly of dry leaves, specially selected and carefully built into a robust weatherproof structure, by a method appropriate both to the hedgehog and the materials used. Construction of winter nests was closely correlated with environmental temperature. The life history of hibernacula is reviewed and it is shown that nests may persist for well over a year, though the leaves of which they are made normally decay completely in a much shorter time. Nests built in brambles, with plenty of support last longer than those in less preferred sites. The construction of winter nests was strictly seasonal, but their decay was gradual, with rapid deterioration at the end of the winter. About 30% of nests persisted till the following winter, though were not re-occupied. Over half of the nests built were occupied for one month or less, though some were in continuous use for up to six months. New nests were built even in midwinter, but the likelihood of their being occupied immediately was affected by the weather. Hedgehogs rarely shared a nest, though empty nests were sometimes taken over by small mammals or Hymenoptera. Most hedgehogs that died in their nests during winter were juveniles perhaps too inexperienced to construct an adequately protective nest. The importance of the nest in a hedgehog's life, particularly during hibernation may be a significant feature in determining both its distribution and its habitat choice.
TL;DR: The effect of various salts at pH 5.6 to 6.2 on the enthalpy, ΔHD, and temperature, TD, of denaturation of swollen bovine achilles tendon collagen was studied.
TL;DR: In this article, it was shown that cavitation can occur when flowing magma in a pipe encounters a constriction, and that in the ensuing collapse of a bubble very substantial transient dynamic pressures, of magnitude sufficient to be of thermodynamic importance for diamond synthesis, can be produced.
Abstract: LET us grant, in accordance with Galimov's proposals1, that cavitation can occur when flowing magma in a pipe encounters a constriction, and that in the ensuing collapse of a bubble very substantial transient dynamic pressures, of magnitude sufficient to be of thermodynamic importance for diamond synthesis, can be produced. In granting this, we overlook some quantitative details in his calculation, such as the apparent implication that the bubbles would contain gas at 10 or 20 kbar, and yet that their compression (by a factor of 64,000 in volume) can be calculated by ideal gas theory. He ignores the fundamental difference in rate control between martensitic conversion of crystals from one modification to another, which makes a product of the same chemical composition as the starting material, and other processes of crystal growth requiring a composition change. In the former class, to which production of diamond by the action of shock waves on graphite belongs, the limit on growth velocity is essentially the shock wave velocity. Thus, so far as that is concerned, quite a large diamond might be made within a few microseconds. Further characteristics of martensitic processes are, however, that the product takes the form of thin lenses, whereby the constraint by the matrix on shape change in the converting region is minimised and, second, that as a rule there is a multiplicity of orientations of the martensitic product in the parent crystal, so that a microcrystalline product results.
TL;DR: In this article, a numerical integration of the Kirkwood-Buff-Fowler equations is used to obtain the surface tension and surface energy of a number of simple liquids, and the results on surface energy are thermodynamically inconsistent with those on surface tension.
Abstract: Values of the surface tension and surface excess internal energy of a number of simple liquids are obtained by numerical integration of the Kirkwood-Buff-Fowler equations. All calculations are based on the Lennard-Jones potential with parameters which are known to reproduce the thermodynamic properties of the bulk liquids. Agreement between theoretical and experimental values of surface tension at the triple point is good, except for neon, and it is concluded that the Kirkwood-Buff-Fowler treatment is numerically more satisfactory than had previously been supposed. On the other hand, poor results are obtained for surface energy because the variation of surface tension with temperature is greatly underestimated. Furthermore, the results on surface energy are thermodynamically inconsistent with those on surface tension. Agreement with experimental data on surface tension at higher temperatures can be achieved by taking into account the non-zero width of the liquid-vapour transition region. By forcing agreem...
TL;DR: A new enzyme, β- l -arabinosidase, has been detected in the dormant seeds of Cajanus indicus as mentioned in this paper, which does not hydrolyse an α- d -galactoside or an α -d -fucoside.
TL;DR: A table of real cubic fields with discriminant less than 20,000 was given by Godwin and Samet as mentioned in this paper, and a complementary table of 3169 non-conjugate complex cubic fields, with discriminants greater than -20,000, was constructed by Delone and Faddeev.
Abstract: A table of real cubic fields with discriminant less than 20,000 is given by Godwin and Samet [6]. This paper describes the construction of a complementary table of the 3169 non-conjugate complex cubic fields with discriminants greater than -20,000, which extends the existing table for discriminants greater than -1000 given by Delone and Faddeev [3]. The basis of this calculation is the following theorem, similar to one used by Godwin [5].
TL;DR: Observations on cross infection by Trichophyton erinacei in captive and wild hedgehogs indicate that the fungus is not highly pathogenic, and it is suggested that bodily contact, especially during fights, is the most likely means of cross infection.
Abstract: Observations on cross infection by Trichophyton erinacei in captive and wild hedgehogs indicate that the fungus is not highly pathogenic. A healthy animal may be exposed to an infected one for some months before itself becoming infected. Infected animals may remain free of lesions for long periods, but the disease eventually increases in extent and severity. No case of regression of infection or of recovery was noted. Possible means of transmission of the fungus are considered, and it is suggested that bodily contact, especially during fights, is the most likely means of cross infection. Low body temperature and reduction of movement during hibernation are both likely to slow down the progress of the disease and reduce the chances of cross infection.
TL;DR: Worms of secondary infections of Raillietina cesticillus established in 10-week-old birds but failed to grow mature strobilae were taken as an indication of resistance to the cestode as discussed by the authors.
Abstract: Worms of secondary infections of Raillietina cesticillus established in 10-week-old birds but failed to grow mature strobilae. This was taken as an indication of resistance to the cestode. The resistance was inhibited by the immunosuppressant and anti-inflammatory drug dexamethasone, which prevented the local inflammation around attached scolices characteristic of secondary infections of R. cesticillus. Mast cell hyperactivity and eosinophil infiltration in intestinal tissues and immunofluorescent antibodies in sera of infected birds were also demonstrated.
Scolices without strobilae from refractory hosts with both primary and secondary infections regrew their strobilae when transplanted into susceptible hosts.
TL;DR: Brachygaster minutus is a parasite of the oothecae of three species of British field-dwelling cockroaches belonging to the genus Ectobius, which has previously received very little attention probably due to its restricted occurrence in Britain and the difficulties encountered in its collection.
Abstract: Summary Brachygaster minutus is a parasite of the oothecae of three species of British field-dwelling cockroaches belonging to the genus Ectobius. This species has previously received very little attention probably due to its restricted occurrence in Britain and the difficulties encountered in its collection. The life cycle and development of the parasite is described. The species is solitary in habit, the single larva overwintering within the ootheca as a final instar. The emergence of the adult the following summer is perfectly synchronized with the occurrence in the field of the particular cockroach species. Aspects of the mating and oviposition behaviour of the parasite are described.
TL;DR: The behaviour of the enzyme on DEAE-cellulose differs from that of a microbial β-1,4-glucanase studied previously although the molecular weights of the two enzymes appear to be identical.
Abstract: 1. 1. A β-1,4-glucan hydrolase was separated from the other β-glucanases present in snail juice by molecular-sieve chromatography on Biogel P-60. 2. 2. The enzyme was further purified by an affinity chromatographic procedure based on interaction with DEAE-cellulose, and finally by rechromatography on Biogel P-60. 3. 3. The behaviour of the enzyme on DEAE-cellulose differs from that of a microbial β-1,4-glucanase studied previously although the molecular weights of the two enzymes appear to be identical.
TL;DR: The results suggest that ribosomal RNA or possibly AMP-rich RNA must be implicated in the light effect of carotenogenesis.
Abstract: Cycloheximide, actinomycin D, puromycin, 5-fluorouracil and 5-fluorodeoxyuridine, all inhibitors of nucleic acid and protein synthesis, have been used to investigate at which level light affects carotenogenesis. The first three compounds inhibited both total protein and total carotenoids whereas the other two inhibited protein but not carotenoids. The results suggest that ribosomal RNA or possibly AMP-rich RNA must be implicated in the light effect.
A scheme involving protein synthesis is proposed to account for the results obtained.
TL;DR: In this paper, a general theory is presented which describes stimulated scattering in a liquid medium, in terms of the refractive index modulation induced in the medium by the strong electric fields of the laser and scattered beams.
Abstract: A general theory is presented which describes stimulated scattering, in a liquid medium, in terms of the refractive index modulation induced in the medium by the strong electric fields of the laser and scattered beams. It is shown that this modulation also results in the Bragg reflexion of low-power light of other frequencies incident on the scattering region. Results are presented which indicate that this Bragg reflexion affords a convenient technique for the comprehensive investigation of the modulation.
TL;DR: In this article, Monte-Carlo computations in the NpT-ensemble are reported for solid and liquid potassium chloride at atmospheric pressure and temperatures between the melting and boiling points.