Showing papers by "Royal Holloway, University of London published in 1990"

Cognitive Psychology: A Student's Handbook

Abstract: Preface. 1. Approaches to Human Cognition. Part 1. Visual Perception and Attention. 2. Basic Processes in Visual Cognition. 3. Object and Face Recognition. 4. Perception, Motion and Action. 5. Attention and Performance. Part 2. Memory. 6. Learning, Memory and Forgetting. 7. Long-Term Memory Systems. 8. Everyday Memory. Part 3. Language. 9. Reading and Speech Perception. 10. Language Comprehension. 11. Language Production. Part 4.: Thinking and Reasoning. 12. Problem Solving and Expertise. 13. Judgement and Decision Making. 14. Inductive and Deductive Reasoning. Part 5. Broadening Horizons. 15. Cognition and Emotion. 16. Consciousness. Glossary. References.

The Solid Earth: An Introduction to Global Geophysics

Abstract: The Solid Earth is a general introduction to the study of the physics of the solid Earth, including the workings of both the Earth's surface and its deep interior. The emphasis throughout is on basic physical principles rather than instrumentation or data handling. The second edition of this acclaimed textbook has been revised to bring the content fully up-to-date and to reflect the most recent advances in geophysical research. It is designed for undergraduates on introductory geophysics courses who have a general background in the physical sciences, including introductory calculus. It can also be used as a reference book for graduate students and other researchers in geology and geophysics. Each chapter ends with exercises of various degrees of complexity, for which solutions are available to instructors from www.cambridge.org/9780521893077. The book contains an extensive glossary of geological and physical terms, as well as appendices that develop more advanced mathematical topics.

Measures of Psychological Well‐being and Treatment Satisfaction Developed from the Responses of People with Tablet‐treated Diabetes

Abstract: Psychological outcome measures of Well-being and Treatment Satisfaction have been designed and developed for people with tablet-treated Type 2 diabetes. The Well-being scale includes three six-item sub-scales to measure Depression, Anxiety, and Positive Well-being. A prime consideration when selecting items for the psychological well-being measures was to minimize the confounding of diabetic symptomatology with the somatic symptoms of depression and anxiety. Cronbach's alpha indicated that each of the Well-being sub-scales and the Treatment Satisfaction scale was internally reliable (alphas ranged from 0.70 to 0.88) and evidence for construct validity was provided by predicted associations with other variables collected at the time of the study. For example, lower Well-being scores were associated with being overweight (Depression: p less than 0.05; Anxiety: p less than 0.001) while greater Satisfaction with Treatment was associated with lower HbA1 levels (p less than 0.001) and lower percent ideal body weight (p less than 0.01). These scales should prove particularly useful where measures of quality of life are required to complement metabolic variables when evaluating new treatments, education programmes, and other interventions, or in the routine auditing of established methods of treatment.

Attributions of blame for marital violence - a study of antecedents and consequences

Abstract: A sample of 70 women who had experienced marital violence were studied to assess degree of placing blame on self and on partner for violence. It was hypothesized that the focus of blame would change with marital circumstances and that different types of attributions for violence while in the violent relationship would be associated with different antecedent and outcome factors. Women currently living with violent partners reported the highest rate of self-blame, and women no longer living with such a partner reported a significant change from past self-blame to current partner-blame. Attributions while in the relationship fell into four categories; characterological self- and partner-blame, behavioral self-blame, and partners' situational response. Characterological self-blame was shown to be most highly associated with repeated physical or sexual abuse in childhood, lack of social support concerning the violence, and a high rate of depression once out of the relationship. (Abstract Adapted from Source: Journal of Marriage and the Family, 1990. Copyright © 1990 by the National Council on Family Relations) Domestic Violence Perceptions Domestic Violence Victim Spouse Abuse Perceptions Spouse Abuse Victim Victim Perceptions Violence Against Women Partner Violence Adult Female Adult Perceptions Adult Victim Female Perceptions Female Victim Self Blaming Offender Blaming Offender Responsibility 10-03

The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames

Abstract: Agrobacterium tumefaciens genetically transforms plant cells by transferring a copy of its T-DNA to the plant where it is integrated and stably maintained. In the presence of wounded plant cells this process is activated and mediated by the products of the vir genes which are grouped into six distinct loci. The largest is the virB locus spanning 9.5 kb. Transposon mutagenesis studies have shown that virB gene products are required for virulence but their functions remain largely unknown. To provide information relevant to understanding the function of VirB polypeptides, the nucleotide sequence of the virB operon from a nopaline plasmid, pTiC58, is presented here. Eleven open reading frames (ORFs) are predicted from this sequence. The predicted sizes of 10 of the 11 VirB polypeptides are verified by specific expression in Escherichia coli. Only the product of the smallest ORF potentially encoding a 5.8 kDa polypeptide has not been detected. The initiation of translation of five virB ORFs occurs at codons that overlap the termination codons of the ORF immediately upstream; thus, translational coupling may be an important mechanism for efficient translation of the large virB polycistronic mRNA. Based on hydropathy plot analysis nine of the virB ORFs encode proteins that may interact with membranes; these data support the earlier hypothesis that virB gene products may form a membrane pore or channel to mediate exit of the T-DNA copy (T-strands) from Agrobacterium into the plant cell. A comparison of the two published octopine virB sequences with the nopaline sequence presented here is made.

Do fossil plants give a climatic signal

Abstract: The agreement in the pattern of major biomes with that of climatic zonation of the Earth gives a strong indication that climate is the overriding influence controlling the distribution of plant communities. Three aspects of plants which may be preserved in the fossil state, give a signal of the climatic conditions under which they grew: (1) the present climatic association of their 9nearest living relative9; (2) leaf physiognomy of arborescent plants; (3) the character of their secondary xylem (9wood9 of ordinary usage) reflecting, by the presence or absence of growth rings, the seasonality (or lack of it) in their environment and the potential for tree growth that it offered. The significance and limitations of these 9palaeoclimatic signals9 as they may be read from the fossil plant record are reviewed and evaluated. The recent demonstration that stomatal frequency of leaves is responsive to changes in ambient carbon dioxide partial pressure offers promise for direct palaeobotanical evidence for past changes in the level of this climatically significant atmospheric constituent.

An evaluation of the antioxidant and potential pro-oxidant properties of food additives and of trolox C, vitamin E and probucol.

Abstract: The food additives propyl gallate and vanillin inhibited iron ion-dependent lipid peroxidation in rat-liver microsomes, but stimulated formation of a deoxyribose degrading species, probably hydroxyl radical, from ferric-EDTA and hydrogen peroxide. Propyl gallate accelerated DNA damage by the anti-tumour antibiotic bleomycin, although vanillin did not. The water-soluble vitamin E analogue Trolox C also stimulated bleomycin-dependent DNA damage, but not hydroxyl radical generation from ferric-EDTA and H2O2. Indeed, Trolox C was found to be a powerful scavenger of hydroxyl radical (rate constant < 1010 M−1 s−1). Probucol did not stimulate oxidative damage in any of the systems tested, and is a powerful inhibitor of lipid peroxidation in rat liver microsomes. The ESR spectrum of the radical produced by one electron-oxidation of probucol in ethanol is described.

Carbon isotopic fractionation between CO 2 vapour, silicate and carbonate melts: an experimental study to 30 kbar

Abstract: The carbon isotopic fractionation between CO2 vapour and sodamelilite (NaCaAlSi2O7) melt over a range of pressures and temperatures has been investigated using solid-media piston-cylinder high pressure apparatus. Ag2C2O4 was the source of CO2 and experimental oxygen fugacity was buffered at hematite-magnetite by the double capsule technique. The abundance and isotopic composition of carbon dissolved in sodamelilite (SM) glass were determined by stepped heating and the δ13C of coexisting vapour was determined directly by capsule piercing. CO2 solubility in SM displays a complex behavior with temperature. At pressures up to 10 kbars CO2 dissolves in SM to form carbonate ion complexes and the solubility data suggest slight negative temperature dependence. Above 20 kbars CO2 reacts with SM to form immiscible Na-rich silicate and Ca-rich carbonate melts and CO2 solubility in Na-enriched silicate melt rises with increasing temperature above the liquidus. Measured values for carbon isotopic fractionation between CO2 vapour and carbonate ions dissoived in sodamelilite melt at 1200°–1400° C and 5–30 kbars average 2.4±0.2‰, favouring13C enrichment in CO2 vapour. The results are maxima and are independent of pressure and temperature. Similar values of ≈2‰ are obtained for the carbon isotopic fractionation between CO2 vapour and carbonate melts at 1300°–1400° C and 20–30 kbars.

A reappraisal of the Dinantian floras at Oxroad Bay, East Lothian, Scotland. 2. Volcanicity, palaeoenvironments and palaeoecology

Abstract: The classic late Tournaisian plant-bearing locality at Oxroad Bay was investigated by detailed field mapping, lithological logging, studies of clast orientation, thin-section petrography and analyses of bulk geochemistry. The lithologically and structurally complex, c. 45 m-thick succession includes eight plant-bearing exposures (each consisting of up to 16 phytofossiliferous horizons) that have yielded 43 anatomically-preserved organ-species and 19 adpressed organ-species. All floral assemblages are allochthonous s.l. and demonstrate a wide range of preservation states. They occur in five successive facies (braided flood-plain, shallow volcanigenic lacustrine, terrestrial mass-flow/base-surge, shallow biogenic lacustrine, dominantly terrestrial reworked ashes) that reflect increasing influence of several basaltic tuff-ring volcanoes on an ocean-marginal lowland bordering the Southern Uplands Massif. The variable local climate reflected proximity to the proto-North Sea and eruptive seeding of the atmosphere with ash particles. Base-surges, seismically-initiated mass-flows and volcanically-induced wildfires restricted the development of mature soils and of edaphic climax communities. These disturbances created a sequence of mosaic palaeocatenas that supported a wide range of sub-communities at any one moment in time. At least some of the relatively k-selected species that occupied the preceding, fluvially-dominated terrain were extirpated by the persistent volcanism, yielding to immigrants that were better pre-adapted to the unstable environment. Low levels of competition allowed non-adaptive n-selection, enhancing the establishment potential of evolutionary innovations.

Low-energy electron scattering by HCl

Abstract: The R-matrix method is used to calculate low-energy electron scattering and dissociative attachment cross sections for HCl. Nuclear vibration is included using a non-adiabatic approximation. Two models, differing only in their treatment of polarisation effects, are used. At energies below the v=2 threshold, the cross sections are found to be very sensitive to these effects. The peaks in the vibrational excitation cross sections are seen to correspond to resonance poles in the S matrix and can therefore be interpreted as nuclear excited Feshbach resonances.

Terrane assemblage of the Leinster Massif, SE Ireland, during the Lower Palaeozoic

Abstract: Compilation of Irish Geological Survey mapping is used to construct a synthesis of the tectonic evolution of the Leinster Massif during the Lower Palaeozoic. The massif is interpreted as a series of NE-SW trending tectonostratigraphic terranes of diverse origin and provenance brought together along major sinistral transcurrent faults. With minor discrepancies the age of these terranes decreases from SE to NW. The Precambrian basement Rosslare terrane is succeeded by the Early Cambrian continental margin Cullenstown-Cahore terrane. In the Waterford-Wicklow terrane Late Cambrian-Early Ordovician accreted ocean floor materials are overlain by a Late Ordovician volcanic arc. The Early to Mid-Ordovician accreted ocean floor Dublin terrane to the NW is overthrust by the Early Cambrian continental margin Bray terrane and is followed to the NW by the mainly Silurian Midlands terrane. These terranes were juxtaposed after substantial sinistral movement along transcurrent faults during the Silurian. Consolidation of the massif also took place from SE to NW. Stages in the consolidation are marked by the intrusion of the Saltees (437 Ma), Carrigmore (415 Ma) and Leinster (404 Ma) stitching plutons. Fault movement ceased before the deposition of Late Devonian and Carboniferous sediments on a linking unconformity across the massif.

Antimutagens from Momordica charantia.

Abstract: The antimutagenic principle of the green fruits of Momordica charantia was shown by the micronucleus test to be an intractable mixture of novel acylglucosylsterols. The antimutagens were extracted from the green fruits with ethanol and isolated from the bioactive petroleum ether and carbon tetrachloride extracts by repeated and sequential flash column chromatography. The major component of the mixture is 3-O-[6'-O-palmitoyl-beta-D-glucosyl-stigmasta-5,25(27)-dien and the minor component is the stearyl derivative (Guevara, 1989). At a dosage range in mice of 50-12.5 micrograms extract/g, the mixture reduced by about 80% the number of micronucleated polychromatic erythrocytes induced by the well-known mutagen mitomycin C. Structure-activity correlation studies suggested that the antimutagenic activity may reside in the peculiar lipid-like structure of the acylglucosylsterols. Ingestion of these compounds may result in their absorption in the plasma membrane lipid bilayer which could adversely affect the membrane permeability towards mitomycin C and disrupt the cellular activity of the latter.

Seismic images of continental lithosphere

Abstract: Seismic reflection profiles in USA and West Germany over thirty years ago showed strong reflections from the lower crust but technical advances through the 1970s were needed for the method to image the continental lithosphere. The British Institutions Reflection Profiling Syndicate, BIRPS, found advantage in working offshore and has obtained over 12,000 km of profiles around Britain during the past decade, giving the densest regional coverage anywhere. Reflections are observed from strata in sedimentary basins, from low angle faults that can be followed from surface to mid-crust, from a laterally variable reflective zone in the lower crust, from the Moho and from fault-like features in the upper mantle. There is evidence around Britain that faults bounding sedimentary basins are older structures which have been reactivated. It is argued that lower crustal reflectivity around Britain is mainly due to anastomosing ductile shears which accommodate extension in the lower crust commensurate with extension in the upper crust by faulting and block rotation. There is also evidence of reflections preserved from older orogenic features, so that reflections interpreted as extensional ductile shears in the lower crust may also derive from older features that have been reactivated. Most reflections in the lower crust arise from rocks that have been highly strained. Evidence of lateral variability in the reflective character of the Moho suggests that the Moho has been actively involved in the structural evolution of the lithosphere. Upper mantle reflections are interpreted as shear zones which transfer crustal deformation through the lithosphere.

Microcalorimetric studies of the initial interaction between antimycobacterial drugs and Mycobacterium avium

Abstract: To further our understanding of the mechanisms by which ethambutol potentiates the effect of other antimycobacterial drugs on mycobacteria we have studied the initial physico-chemical interaction between ethambutol and the Mycobacterium avium cell envelope using batch reaction microcalorimetry. When strains of M. avium were exposed to ethambutol an immediate endothermic reaction was recorded. When the M. avium cells were pre-treated with ethambutol this strongly affected the initial interaction between streptomycin and the bacterial cell surface. When the M. avium cells were simultaneously exposed to a combination of ethambutol and streptomycin an altered initial interaction with streptomycin was seen. These data suggest that ethambutol may potentiate the effect of other antibacterial drugs on M. avium by increasing cell wall permeability.

A review : limnological management and biomanipulation in the London reservoirs

Abstract: Low algal biomasses and high water transparencies are a feature of the storage reservoirs that supply most of London’s treated water. This is a result of knowledgeable limnological management and biomanipulation and despite the eutrophic nature of the River Thames with its high nutrients (7 gN m− 3; 1 gP m−3) and particulate organic carbon (2 gC m−3). Built-in possibilities of jetting input water are managed to prevent stratification, to ensure isothermy, to mix chemicals and plankton vertically and horizontally and to manipulate the mixed-depth of the algal populations such that their potential for biomass growth is reduced by light-energy limitation. Spring algal growth is delayed and the spring peak is reduced and curtailed by the grazing impact of considerable biomasses of large-bodied daphnid populations (Daphnia magna, pulicaria & hyalina) whose development is also supported by the continuous input of high riverine algal crops. The existence of a large-bodied daphnid zooplankton in the reservoirs is associated with low levels of fish predation since the late 1960s. Variations in the intensity and nature of this vertebrate predation during the subsequent twenty years (1968–88) are illustrated by the changes that have occurred in the relationship between the phytoplankton and zooplankton biomasses of the April-May-June quarter of the year. This example of the London reservoirs serves to illustrate biomanipulation in deep water bodies by bottom-up as well as top-down effects.

Pb-Sr-Nd isotope and chemical study of the origin of undersaturated and oversaturated shoshonitic magmas from the Borralan pluton, Assynt, NW Scotland

Abstract: Pb–Sr–Nd isotope and major and trace element data are reported for a suite of samples from the Siluro–Ordovician Loch Borralan pluton, NW Scotland. Rock types ranging from pyroxenite through highly potassic melasyenites to quartz syenite were primarily generated by extensive fractional crystallization from mantle derived magmas. All rock types show pronounced Nb-depletion indicating shoshonitic, subduction-related, affinities for the magmas. Sr–Nd–Pb isotope compositions of the undersaturated rocks vary little and indicate derivation from a time-integrated mildly LREE-enriched mantle source very similar to that of the Silurian Lorne shoshonitic lavas further south. This mantle source is very unlikely to be lithosphere stabilized in Archaean times. The slightly younger quartz syenite intrusion contains 10–20% Archaean Pb and Nd indicating that its oversaturated and mildly peraluminous character is a function of assimilation of local Lewisian crust.