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Genetic Variation For Fruit Development Of Pisum Sativum L., With Special Reference To The Effects Of The Rugosus Locus, Christine Mary Smith Jan 1986

Genetic Variation For Fruit Development Of Pisum Sativum L., With Special Reference To The Effects Of The Rugosus Locus, Christine Mary Smith

School of Biological and Marine Sciences Theses

This study has compared various aspects of pea fruit development, using two green-podded lines near-isogenic except for the r locus and a yellow-podded mutant having the genotype gpgp. The gp gene is associated with reduced chlorophyll in the pod wall which then appears yellow. The r gene is associated with a wrinkled appearance of mature dried seed and cotyledonary starch grains which are small and fissured. An ultrastructural survey of tissues from pods, testas and cotyledons showed there to be no effect of the r locus on chloroplast structure. The structure of amyloplasts however, appeared to be affected by the …

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Flow Of Power Law Fluids With Application To Oil Drilling, E. J. Carter Jan 1986

Flow Of Power Law Fluids With Application To Oil Drilling, E. J. Carter

School of Geography, Earth and Environmental Sciences Theses

The thesis is concerned with a theoretical study of the flow behaviour of inelastic power law fluids in two different types of flow situation. These are: 1. The creeping motion of a sphere moving through an expanse of liquid. 2. The combined steady and oscillatory flow of a liquid through a straight tube of circular cross section. The first part of the work is devoted to the prediction of the drag correction factor for a sphere falling slowly through a bounded inelastic power law fluid. The analysis is carried out for the case when the outer spherical boundary has a …

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Metal Methylation In Estuarine Waters, Andrew Paul Walton Jan 1986

Metal Methylation In Estuarine Waters, Andrew Paul Walton

School of Geography, Earth and Environmental Sciences Theses

Metal methylation has been studied in estiiarine waters by directly coupled GC-AAS/llquid nitrogen trapped hydride generation systems and determined accurately. Surveys were carried out in the estuaries of the River Tamar, Camon and Beaulieu (S. England) over a seasonal cycle. Methylated forms of Fb were only observed in rain, drain and estuarine water samples collected in the Tamar. In estuarine waters (GH«)«Fb*'' (<2-10 ng Fb 1"^) was the predominant methylated Fb species. Monomethylarsenic and dimethylarsenic species were observed in the water column in a ll3 estuaries studied. In the Tamar, Beaulieu and Carnon concentrations of methylated As species were similar with concentrations ranging from <0.02-0.7 pg As 1"^. In Tamar porewaters concentrations of methylated As species ranged from< 0.02-0.7 As 1"-^. Methylated forms of Se {Se(CH^)^, 0.5ug Se l"""-) were detected on an occasion in the Carnon. Modelling studies on Pb methylation suggest that conversion of trimethyllead acetate to Ti-IL proceeds by a chemical sulphide-mediated pathway (maximum 2.8% conversion occurred for a biological sediment system). Methylation of inorganic Pb ( H ) salts was not reproducible (maximum conversion of 0,OZQ% for PbGl^) but when observed a biologically mediated methylation process was invoked. From laboratory modelling studies temporal variations in As speciation observed in the Tamar were attributed to seasonal contributions of methylated As species from 3 sources: (i) macro-algae; ( ii ) diatoms; ( iii ) porewaters. The predominance of dimethylarsenic species over monomethylarsenic species in summer reflects the importance of plankton sources. In winter a transition takes place where the predominance of methylated As species occur and concentrations of monomethylarsenic species exceeds that of dimethylarsenic species. This transition is attributed to the increased importance of the porewater source in winter. The significance of metal methylation in the cycling of Pb, As and Se in estuarine waters appears to follow the order Asj>Se>^Fb. The biomethylation of As being highly significant in the transportation of As in the environment.

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Integrated Control Of Cereal Aphids/Barley Yellow Dwarf Virus, Elizabeth Jane Matcham Jan 1986

Integrated Control Of Cereal Aphids/Barley Yellow Dwarf Virus, Elizabeth Jane Matcham

Other Faculty of Science and Engineering Theses

The cereal aphids Rhopalosiphum padi (L.) and Sitobion a venae (F.) cause spread of Barley Yellow Dwarf Virus in autumn sown crops over the winter. Control is achieved by correctly timed insecticide applications, commonly synthetic pyrethroids. Polyphagous predators contribute to the natural control of these aphids. A field investigation into the effects of deltamethrin on polyphagous predators,using barriered plots, showed that natural control may be reduced due to the reduction in numbers of predators over the winter. Also, spring populations, which limit the growth of summer populations of aphids, may be reduced as larvae are most affected. The field dispersal …

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Dispersal In Carabids, Simon C. Newell Jan 1986

Dispersal In Carabids, Simon C. Newell

Other Faculty of Science and Engineering Theses

The study consisted primarily of a number of surveys in brassica fields, using pitfall and gutter traps. At all sites a number of different species of carabids were marked and released. From the pitfall trapping it was found that different carabid species inhabitated different parts of the field, particularly in relation to the field boundaries. Two common species, Nebria brevicollis and Bembidion lampros, over-wintered in the hedgebanks, moving out into the fields in the spring. Two other common species, Pterostichus melanarius and Harpalus rufipes, were primarily associated with the field, but activity in the field boundaries continued later into the …

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Stability And Continuity In Cognitive Performance From Early To Late Infancy, Rachel Cooper Jan 1986

Stability And Continuity In Cognitive Performance From Early To Late Infancy, Rachel Cooper

Other Faculty of Arts, Humanities and Business Theses

This research is concerned with the stability and continuity of cognitive measures throughout the infancy period. A review of the literature showed that standardised infant intelligence tests fail to predict subsequent intellectual performance, and one reason for this may be the dominance of motor based items in the tests, and the relative dearth of measures reflecting cognitive ability. Furthermore, it has been suggested that measures from recently developed procedures, which are considered to reflect learning, memory and discriminative ability in infancy may constitute more useful predictive measures of later intellectual functioning. However, the reliabilities and inter-correlations between these measures have …

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Reproductlve Allocation In Flowering Plants, Ann Margaret Wilson Jan 1986

Reproductlve Allocation In Flowering Plants, Ann Margaret Wilson

School of Biological and Marine Sciences Theses

The proportion of resources which an organism devotes to reproduction has been assumed to be of great evolutionary and ecological significance. However, in previous studies of reproductive allocation (RA) in plants, there has been no consensus of precisely what is being measured nor how it should be measured. An attempt was made to determine the 'best' method of measuring RA and then apply this to a range of species with differing ecological strategies. Under nutrient stress caused by a low N treatment Taraxacum officinale and Poa annua were found to maintain their RA despite up to 4 fold reductions in …

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The Evolution And Structure Of An Intrathermocline Eddy, Ag Kostjanoy, Gi Shapiro Jan 1986

The Evolution And Structure Of An Intrathermocline Eddy, Ag Kostjanoy, Gi Shapiro

School of Biological and Marine Sciences

No abstract provided.

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Dynamics Of An Isolated Interathermocline Eddy, Gi Shapiro Jan 1986

Dynamics Of An Isolated Interathermocline Eddy, Gi Shapiro

School of Biological and Marine Sciences

No abstract provided.

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The Effect Of Dietary Biotin Level On The Productivity Of The Female Pig, Philip Howard Simmins Jan 1985

The Effect Of Dietary Biotin Level On The Productivity Of The Female Pig, Philip Howard Simmins

School of Biological and Marine Sciences Theses

Five experiments were conducted with female pigs to investigate the effects of dietary biotin level on: reproductive performance and hoof integrity over four parities (experiment 1); ovulation rate of the gilt(experiment 2); durability of hoof horn and the phospholipid and neutral lipid profile of perinephric and hoof horn fat (experiments 3 and 4) and milk fat (experiment 5). Experiment 1 showed that changes in reproductive performance and hoof integrity in adult sows occurred when pigs were fed levels of dietary biotin previously considered to have been sufficient to meet the sow's requirements (diet calculated to provide32µg available biotin/kg). Notably, sows …

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Properties Of The Cell Surface Of Aeromonas Salmonicida, Nigel D. Parker Jan 1985

Properties Of The Cell Surface Of Aeromonas Salmonicida, Nigel D. Parker

School of Biological and Marine Sciences Theses

The properties of the cell surface of Aeromonas salmonicida were studied, with particular emphasis on the additional surface layer (A-layer), found on virulent strains. This was identified by electron microscopy, as having a tetragonal subunit morphology; and by electrophoresis of membrane components as a 51 kdal protein on A+ strains. A+ and A- strains, (the latter isolated by growth at elevated temperature), were compared biochemically and their interactions with various cell types investigated. Strains of A. salmonicida possessing the A-layer were shown to be more hydrophobic than those devoid of this protein. The influence of culture age, medium composition and …

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Ontogenetic Studies Of Immunity And Tolerance In Xenopus Laevis (Daudin), Ghassan Mahmoud Al-Johari Jan 1985

Ontogenetic Studies Of Immunity And Tolerance In Xenopus Laevis (Daudin), Ghassan Mahmoud Al-Johari

School of Biological and Marine Sciences Theses

Xenopus laevis injected with sheep erythrocytes (SRBC) at Stage 48 of Nieuwkoop and Faber (1967) showed no evidence of tolerance induction as a result of early exposure to antigen. These experiments showed that priming during the larval stages of development (at Stages 48 and 54 or at Stage 56) led to a positive anamnestic response when the animals were challenged after metamorphosis as toadlets. It was not, however, possible to demonstrate enhanced secondary responses within the larval period itself. The effect of the alkylating agent, cyclophosphamide on the generation of immunological memory varies at different stages of development. In the …

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Offshore Fouling Communities And Settlement And Early Growth In Tubularia Larynx (Ellis And Solander) And Pomatoceros Triqueter (L.), Roy Martin Moate Jan 1985

Offshore Fouling Communities And Settlement And Early Growth In Tubularia Larynx (Ellis And Solander) And Pomatoceros Triqueter (L.), Roy Martin Moate

School of Biological and Marine Sciences Theses

The horizontal and vertical distribution of the macro-fouling organisms, both flora and fauna, associated with offshore structures was studied. Offshore buoys located around the coasts of Britain (38) and Norway (10), were used as sites for the collection of material. Sites were visited annually, when possible, over the period 1978-1983. Numerical clustering techniques and indicator species analysis were used to reveal broad geographical categories in the fouling community data. Eight major Site Groups were identified amongst U.K. sites, and three from Norway; whilst within each site group characteristic species were also identified. The frequency and abundance of Tubularia larynx and …

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Ecological Aspects Of Hepatic Microsporidiosis In Coastal Waters With Particular Reference To The Host Taurulus Bubalis, Juliet Anne Stubbs Jan 1985

Ecological Aspects Of Hepatic Microsporidiosis In Coastal Waters With Particular Reference To The Host Taurulus Bubalis, Juliet Anne Stubbs

School of Biological and Marine Sciences Theses

Hepatic microsporidia were investigated from 5 species of fish, namely Taurulus bubalis (Euphr.), Crenilabrus melops, (L.), Gaidropsarus mediterraneus (L.), Ciliata mustela (L.). and Scophthalmus maximus (L.) and intramuscular microsporidia from 2 species, namely Taurulus bubalis and Cottus gobio L. Detailed ultrastructural studies carried out on hepatic microsporidia from T. bubalis showed it to be a new species belonging to the genus Microgemma (Ralphs) and it is named here as Microgemma dunkerli sp. n. Although hepatic microsporidia from the other species of fish are included in Microgemma, insufficient data was available to determine whether these were synonomous with M. dunkerli or …

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The Synoptic Variability Of The Horizontally Nonhomogeneous Upper Ocean Layer, Gi Shapiro Jan 1985

The Synoptic Variability Of The Horizontally Nonhomogeneous Upper Ocean Layer, Gi Shapiro

School of Biological and Marine Sciences

No abstract provided.

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On The Structure Of Wave Fronts In Nonlinear Dissipative Media, Gi Barenblatt, My Ivanov, Gi Shapiro Jan 1985

On The Structure Of Wave Fronts In Nonlinear Dissipative Media, Gi Barenblatt, My Ivanov, Gi Shapiro

School of Biological and Marine Sciences

No abstract provided.

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Geochemical Cycles Of The Atmophile Elements Arsenic And Antimony, Laurence Stuart Austin Jan 1984

Geochemical Cycles Of The Atmophile Elements Arsenic And Antimony, Laurence Stuart Austin

School of Biological and Marine Sciences Theses

Atmospheric aerosol samples from coastal and open ocean environments in the North Atlantic were analysed for the atmophile elements arsenic and antimony, and for the marine tracers sodium and magnesium. The aerosol concentrations of sodium and magnesium were similar in both environments, about 2000 ng Na (SCM)ˉ¹ and 320 ng Mg (SCM)ˉ¹. The atmophiles were more concentrated in the coastal aerosol, 0.67 ng As(SCM)ˉ¹ and 0.32 ng Sb (SCM)ˉ¹, than in the open ocean aerosol, 0.07 ng As (SCM)ˉ¹ and 0.086 ng Sb (SCM)ˉ¹, and as continental particles were only observed in the coastal aerosol, this indicates that arsenic and …

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Immunological Memory In Young Fish And Amphibians: Studies On Cyprinus Carpio, Chelon Labrosus And Xenopus Laevis, Mohammad Sharif Mughal Jan 1984

Immunological Memory In Young Fish And Amphibians: Studies On Cyprinus Carpio, Chelon Labrosus And Xenopus Laevis, Mohammad Sharif Mughal

School of Biological and Marine Sciences Theses

This study asks whether antigens encountered early in life by animals with free-living larvae can prime the immune system to yield memory responses on subsequent exposure and, if so, whether positive immunity or immunological tolerance is induced. In 4-week old carp, Cyprinus carpio, the thymus dependent antigen human gamma globulin (HGG) was tolerogenic both in soluble form and attached to latex particles, Formalin-killed Aeromonas salmonicida bacteria, in contrast, elicited primary antibody production and induced enhanced secondary responses. By the age of 9-10 weeks HGG was no longer tolerogenic even when injected into the thymus or administered orally. Despite their antibody …

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The Germination Requirements Of Naturally Buried Seeds With Particular Reference To Fluctuating Temperatures, Jean Carol Whatley Jan 1984

The Germination Requirements Of Naturally Buried Seeds With Particular Reference To Fluctuating Temperatures, Jean Carol Whatley

School of Biological and Marine Sciences Theses

An apparatus is described which enables a layer of soil, containing naturally buried seeds, to be subjected to controlled temperature fluctuations over the range 5 C to 30 C, in the presence or absence of light. Results obtained from the use of this apparatus are presented for fourteen species, all common constituents of the buried seed bank and nearly all weeds of arable land or pasture. At least partial inhibition of germination by darkness is found in all fourteen species and stimulation of germination by temperature fluctuations in all but one. In several species strong inhibition by certain constant temperatures …

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Hepatic Microsporidiosis Of Juvenile Grey Mullet, Chelon Labrosus, With Particular Reference To Parasite Development And Transmission, James R. Ralphs Jan 1984

Hepatic Microsporidiosis Of Juvenile Grey Mullet, Chelon Labrosus, With Particular Reference To Parasite Development And Transmission, James R. Ralphs

School of Biological and Marine Sciences Theses

Microgemma hepaticus gen.n.sp.n. is described from the liver of juvenile mullet, Chelon labrosus. Development occurs within xenomas, of diameter 500 µm. These have microvillar surfaces, encircling bands of mitochondria and a reticulate nucleus with many nucleoli. Meronts are plasmodial, divide by plasmotomy and are enclosed within host membranes. Sporonts are free in the cytoplasm and divide by multiple exogenous budding. In sporogenesis the polar sac is formed from golgi vesicles, the manubrium form a dense golgi body and the coiled polar filament form a spiral cisterna linked with the perinuclear membrane system and golgi reticulum. This was also implicated in …

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The Removal And Remobilisation Of Heavy Metals During Estuarine Mixing, David Roger Ackroyd Jan 1983

The Removal And Remobilisation Of Heavy Metals During Estuarine Mixing, David Roger Ackroyd

School of Biological and Marine Sciences Theses

Elemental analyses have been made of dissolved, suspended particulate and sedimentary Cu, Mn, Zn following axial surveys of the Tamar Estuary. Continuous monitoring of the estuarine master variables was made during each survey. Selective digestion methods were applied to the particulate and sediment samples to determine the detrital and non-detrital fractions. These experiments showed that in general about 80-100% Mn, 60% Zn and 20% Cu were in the non-detrital form. Rank order correlation tests of the sediment results showed that the summer profiles were consistently different to 20 randomly generated profiles of the same data. In contrast the winter distribution …

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Pronoun Interpretation In Reading, Edward Lionel Whitehead Jan 1983

Pronoun Interpretation In Reading, Edward Lionel Whitehead

School of Psychology Theses

This research investigated the comprehension of anaphoric pronouns in reading. Chapter, I explains the importance of this feature of text processing, and reviews the relevant psychological literature. One -important feature of pronoun interpretation is the fact that antecedents vary in accessibility in response to aspects of text content and structure; antecedents which are readily acessible to pronominal reference are said to be foregrounded. The most common theoretical explanation of foregrounding is the claim that foregrounded antecedents are held in working memory. The review also shows reasons why good and poor readers might differ in sensitivity to foregrounding. Experiments 1-3 investigated …

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The Dispersal Of Cabbage Root Fly In Relation To Agricultural Practice, Kirk I. Alexander Jan 1983

The Dispersal Of Cabbage Root Fly In Relation To Agricultural Practice, Kirk I. Alexander

Other Faculty of Science and Engineering Theses

The study aimed to estimate the dispersal rate of wild cabbage root flies in agricultural systems, to test a migration hypothesis and the predictions of a computer simulation model. The dispersal rate was determined by a new method, from the age-grouping of wild flies instead of releasing marked culture flies. The mean distance dispersed was calculated from-the slope of density of captured flies on distance; the mean age was calculated from laboratory measurements of development at constant temperatures. A new method of male age determination was developed, based on the changes in pupal fat and testes colour. The published method …

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Dynamics Of A Slowly Moving Front In A Shallow Water Body., Gi Shapiro Jan 1983

Dynamics Of A Slowly Moving Front In A Shallow Water Body., Gi Shapiro

School of Biological and Marine Sciences

The movement of fronts occurring upon interaction of water masses differing in density is examined. Some examples are the propagation of light fresh water over the surface of heavier salt water in coastal regions of seas, the situations occurring when warm waters are discharged by industrial enterprises and electric power stations, the intrusion of sea water in the form of a 'salt wedge' into river estuaries, etc. Under rather general assumptions, the solution of the three-dimensional transient problem of slow movement of a front in a shallow, two-layer stratified water body is reduced to the solution of two coupled equations …

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Spreading Of A Viscous Fluid Over A Horizontal Surface., Gi Shapiro Jan 1983

Spreading Of A Viscous Fluid Over A Horizontal Surface., Gi Shapiro

School of Biological and Marine Sciences

The three-dimensional spreading of a thin viscous fluid layer over a horizontal surface is examined allowing for the gravitational force and surface tension. Using an asymptotic expansion based on two small parameters (Fronda number and the relation of the layer thickness to its characteristic length) nonlinear equations that derive the evolution of a free surface are derived. The analytical results are compared with experimental data.

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Production And Properties Of Extracellular Factors From Aeromonas Salmonicida, Richard W. Titball Jan 1983

Production And Properties Of Extracellular Factors From Aeromonas Salmonicida, Richard W. Titball

School of Biological and Marine Sciences Theses

The production of extracellular products by Aeromonas salmonicida, in vitro, has been investigated. The results indicated that the bacterium produces at least two haemolytic activities in vitro. Unshaken cultural conditions favoured the production of a haemolysin with a broad spectrum of activity against various erythrocyte types (H-lysin), whilst shaken cultural conditions favoured the production of a haemolysin active against trout erythrocytes (T-lysin). The effects of growth medium type and culture conditions on the production of these haemolytic activities has been investigated. The activity of the T-lysin appeared to be attributable to the combined effects of an activity which caused incomplete …

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Accuracy Improvement In Wind-Speed And Direction Shipboard Measurements Based On Aerodynamic Trials Of A Ship Model, Ya Romanov, Ib Fedorova, Ms Chervyakov, Gi Shapiro Jan 1983

Accuracy Improvement In Wind-Speed And Direction Shipboard Measurements Based On Aerodynamic Trials Of A Ship Model, Ya Romanov, Ib Fedorova, Ms Chervyakov, Gi Shapiro

School of Biological and Marine Sciences

No abstract provided.

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Polycyclic Aromatic Hydrocarbons In The Tamar Estuary, James Readman Jan 1982

Polycyclic Aromatic Hydrocarbons In The Tamar Estuary, James Readman

School of Geography, Earth and Environmental Sciences Theses

The high particulate association of PAH in aquatic systems has often been attributed to the hydrophobic nature of the compounds leading to adsorption. Results presented i n this thesis strongly suggest that a significant proportion of PAH in the Tamar are particle-incorporated and unavailable for dynamic partition and physical, chemical and biological fates. The generally uniform PAH composition identified throughout the estuary is highly indicative of a combustion or road and urban runoff source. PAH distrubution in a dated Tamar Estuary sediment core showed an exponential decrease with depth and identified dramatic increases in PAH flux during the last 20 …

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The Dynamics Of The Nonstationary Atmospheric Front, Gi Shapiro Jan 1982

The Dynamics Of The Nonstationary Atmospheric Front, Gi Shapiro

School of Biological and Marine Sciences

No abstract provided.

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Causal Attribution And Depression, Atmane Ikhlef Jan 1982

Causal Attribution And Depression, Atmane Ikhlef

School of Psychology Theses

This thesis reports a series of experiments conducted to elucidate the nature of the relationship between attribution and depression. After an extended review of the literature on attribution and depression it was concluded that further research is needed to evaluate the aetiological importance of depressogenic attributions, and also to elucidate the nature of the relationship they may entertain with depression. A series of experiments and studies were performed to address these and other issues. In experiments l-3 subjects' attributions for success and failure were manipulated and their effects on subsequent mood, expectations and psychomotor performance were assessed. The results showed …

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