Showing papers by "Royal Holloway, University of London published in 1980"

Pairwise additive effective potentials for nitrogen

Abstract: A number of pairwise additive intermolecular potentials have been used in the study of properties of nitrogen in the solid, liquid and gas phases. It is shown that a simple model can account satisfactorily for a wide range of phenomena.

Crusading as an act of love

Abstract: In the 1260s the French poet Rutebeuf, lamenting the failure of his countrymen to move themselves to recapture Jerusalem, exclaimed that ‘the fire of charity is cold in every Christian heart’? These writers used the theological word curitas, charitei for Christian love, heightened it in a traditional Christian way with the words ‘fired,’ ‘fire’, and linked it to the crusades. Since love has always been held to be fundamental to all Christian ethics, including the ethics of violence, it is worth asking how representative they were of the apologists for the crusading movement. I hope to show that the idea of the crusader expressing love through his participation in acts of armed force was an element in the thinking of senior churchmen in the central Middle Ages. An understanding of this can help us place the crusades in the context of the spiritual reawakening of western Europe that accompanied the eleventh-century reform movement. Christian love, however, was presented to the faithful in a way that they would understand, rather than in the form that would have reflected the complexities of the relationship between violence and charity as understood by theologians and canon lawyers. My discussion is limited to the justification of crusades to the East, although crusaders were not by any means only to be found in expeditions launched to recover or aid the Holy Land; they also campaigned in Spain, along the shores of the Baltic and even in the interior of western Europe: Christian charity encompasses love of God and love of one’s neighbour, and both these expressions of love were touched on by apologists for the crusades: in September 1096 Pope Urban I1 promised the indulgence to those Bolognese who joined the First Crusade, ‘seeing that they have committed their property and their persons out of love of God and their neighbour’;5 and St Bernard, writing in the 1140s of news of Muslim vic-

Biochemistry of α-D-Galactosidic Linkages in the Plant Kingdom

Abstract: Publisher Summary This chapter provides an overview of the biochemistry of α- D -Galactosidic linkages in the plant kingdom. Sucrose is a disaccharide that is most widespread amongst higher plants; its concentration varies from species to species. The metabolism of this disaccharide is well documented. Sucrose is formed as a major product of photosynthesis in higher plants and is generally the main form of translocate from leaves to other organs. It is a major carbohydrate-storage material that provides a ready source of D -glucose and D -fructose for the liberation of energy. Sucrose is also an important precursor for the synthesis of D -glucosyl esters of nucleoside diphosphates, and thus it takes part in the biosynthesis of complex oligosaccharides and polysaccharides. Combination of D -galactose with the D -glucosyl or D -fructosyl group of the sucrose molecule gives rise to a number of oligosaccharides; these are, generally, α- D -galactosides. The chapter discusses in detail about α- D -galactosides of sucrose. It also describes the α- D -galactosides of polyols and presents an overview of α- D -galactopyranosyl-specific lectins.

The Tupaiid Dentition

Abstract: In discussions of the relationships of the Tupaiidae to other mammals, the dentition has received relatively little attention. Its evolutionary plasticity makes the dentition very useful in differentiating species and genera, but at higher taxonomic levels its value is diminished because it is particularly subject to parallel evolution. Nevertheless, comparison with fossil groups must inevitably rest very largely on dental studies, as teeth provide such a large part of the evidence on which mammalian paleontological history is based. The purpose of this chapter is to describe the characteristic features of the dentition of living Tupaiidae and the principal variations to be found within the family. Comparisons will then be made with primates and with various families of fossil insectivores that have been proposed as possible tupaiid relatives.

Simulation of road traffic conflicts at T-junctions:

Abstract: This paper describes an event-stepping (discrete- event) simulation model of a nonurban T-junction. The model is intended for investigating the risk of traffic accidents at such junctions, using a version of the traffic-conflict technique. The model uses empirical data and predicts the number and severity of conflicts as a function of various traffic and behavioural parameters. Some applications of the model are outlined. The traffic-handling capacity of the junction and delays at it are not considered.

A bioenergetic study of a benthic nematode, plectus palustris de man 1880, throughout its life cycle : II. Growth, Fecundity and Energy Budgets at Different Densities of Bacterial Food and General Ecological Considerations.

Abstract: Growth and reproduction of the parthenogenetic freshwater nematode,Plectus palustris, were studied at different controlled levels of food densities at 20° C. A bacteria-sloppy agar mixture was used as substrate and food medium. No growth or reproduction occurred at the lowest food density (8.107 bacterial cells ml-1). At 8.108 cells ml-1, the larval duration was 18.5 days, the instantaneous growth rate (g) of young larvae 0.2 d-1 and the daily fecundity rate during a prolonged period of constant egg production 12.6 eggs·d-1. At a food density of 8.109 cells ml-1, the corresponding values are 12.5 days, 0.4 d-1 and 37.7 eggs d-1.By including the data on respiration from a previous paper (Klekowski et al., 1979), the energetics of the species at different food densities can be discussed: production processes are apparently more dependent on food supply than respiration. However, prolongation of the larval phase in lower food densities greatly increases the cumulated respiratory costs per unit production. A second point is the ability to produce smaller-sized primiparous females in sub-optimal food which shortens the immature life period and serves to reduce the burden of cumulated metabolic costs for attaining sexual maturity.A comparison of the range of food densities used in the experiments with bacterial densities known from lake sediments of different trophic type suggests that food is likely to be the main factor governing the population dynamics of bacterivorous species under field situations.

The distribution of dinoflagellates around the british isles in july 1977: a multivariate analysis

Abstract: Data on the distribution of dinoflagellates in the surface waters around the British Isles in July 1977 were analysed by correspondence analysis. Four communities of dinoflagellates were recognized, and the occurrence of each was related to various environmental parameters. The vertical stability of the water column is considered to be the most important factor in determining the relative abundance of individual species.

Isoenzymes in development and differentiation

Abstract: Development is the process by which a programme of selective gene expression, operating on a constant pool of genetic information produ­ces a complex adult organism from a single fertilized cell. A major aspect of this process is tissue differentiation, i.e. the generation of the many cell types, each with specific physical and metabolic character­istics, which are essential to the diverse and integrated functions of that adult organism. It will already be clear that differential gene expression gives rise to tissue-specific isoenzyme patterns in the adult and since these are generated from a single precursor pattern at the one-cell stage, obviously an intricate series of isoenzyme changes must occur during development. These changes have interested developmental biologists from the earliest days of isoenzymology.

Modulation of L-phenylalanine ammonia-lyase by pathway intermediates in cell suspension cultures of dwarf french bean (Phaseolus vulgaris L.).

Abstract: The increase in extractable phenylalanine ammonia-lyase (PAL;EC 4.3.1.5.) activity induced in French bean cell suspension cultures in response to treatment with autoclaved ribonuclease A was inhibited by addition of the phenylpropanoid pathway intermediates cinnamic acid, 4-coumaric acid or ferulic acid. The effectiveness of inhibition was in the order cinnamic acid>4-coumaric acid>ferulic acid. Cinnamic acid also inhibited the PAL activity increase induced by dilution of the suspensions into an excess of fresh culture medium. Addition of low concentrations (<10-5M) of the pathway intermediates to cultures at the time of application of ribonuclease gave variable responses ranging from inhibition to 30–40% stimulation of the PAL activity measured at 8 h. Following addition of pathway intermediates to cultures 4–5 h after ribonuclease treatment, rapid increases followed by equally rapid declines in PAL activity were observed. The cinnamic acid-stimulated increase in enzyme activity was unaffected by treatment with cycloheximide at a concentration which gave complete inhibition of the ribonuclease-induced response. However, cycloheximide completely abolished the subsequent decline in enzyme activity. Treatment of induced cultures with α-aminooxy-β-phenylpropionic acid (AOPPA) resulted in increased but delayed rates of enzyme appearance when compared to controls not treated with the phenylalanine analogue. The results are discussed in relation to current views on the regulation of enzyme levels in higher plants.

The 1946 Punjab Elections

Abstract: On August 21st 1945 the viceroy announced that elections would be held that Winter to the Central and Provincial Legislative Assemblies. They were to precede the convention of a constitution-making body for British India. The Muslim League had to succeed in this crucial test if its popular support of its demand for Pakistan was to be credible. In particular it had to succeed in the Punjab as there could be no Pakistan without that province. But in the Punjab's last elections held in 1937 the League had fared disastrously. It had put forward a mere seven candidates for the 85 Muslim seats and only two had been successful. In the 1946 elections the League won 75 of the total Muslim seats. This improvement in its performance which had momentous implications for the future for the subcontinent requires explanation.

Graphs with even girth and small excess

Abstract: Let G be a regular graph with even girth g = 2r ≥ 4 and valency k ≥ 3. It is well known, and easy to prove, that G must have at least n0 = n0(g, k) vertices, where

Methods of estimation

Abstract: The practical man may entertain some misgivings about the methods discussed in the last two chapters. Bayesian point estimation appears to be very flexible, but if there is no secure basis for a particular prior distribution and only a sketchy idea of the loss function, is there not a danger of drawing misleading conclusions? As to the principle of best unbiased estimation, he might complain that sufficient statistics are sometimes excessively numerous or possess incomplete distributions (these last objections are illustrated in the following two examples). There is a clear demand for routine procedures, of wide applicability, which will (generally) produce unique estimators. Such estimators should, in some sense, be ‘good’. However, we might be prepared to sacrifice some degree of optimality in small samples, provided efficiency tended to be high in large samples. Two well-established routines are discussed in this chapter.

A method for testing the order of an autoregressive-moving average process

Abstract: SUMMARY A procedure is suggested for testing the order of an autoregressive-moving average process which is based on the same set of residual serial correlations as the Box-Pierce test. However, the present method has advantages in terms of its sensitivity to discriminating between alternative models.