Showing papers by "Durham University published in 1988"

Analysis of a complete galaxy redshift survey – II. The field-galaxy luminosity function

Abstract: Analyse statistique de la fonction de luminosite des galaxies de champ de plusieurs catalogues. Les differentes methodes d'estimation sont testees. On montre que la fonction de luminosite de champ peut etre decrite par une fonction de Schechter dont on calcule les differents parametres

Granite emplacement mechanisms and tectonic controls: inferences from deformation studies

Abstract: This paper is a structural and tectonic approach to the emplacement and deformation of granitoids. The main methods available in structural geology are briefly reviewed and this emphasises that (a) a wealth of data, particularly strain and shear sense, which pertain to these problems, can be determined in and around plutons; (b) given the nature, unlike many other crustal rock types, of granites to crystallise from isotropic through weakly anisotropic crystal suspension fluids, that deformation which has occurred in these states may not be well preserved; and (c) it is entirely possible, using this methodology, to separate deformation resulting from externally originating tectonic stresses from that which is associated with internal magma-related stresses. It is also recommended that the genetically-based Cloosian classification of granite fabrics and structures into “primary” (magmatic flow/magmatic flow current) and “secondary”, be abandoned and that a more observationally-based approach which classifies granite deformation fabrics and structures according to their time of occurrence relative to the crystallisation state of the congealing magma, be adopted (i.e. pre-full crystallisation deformation and crystal plastic strain deformation).Examples of recent, structurally based, studies of emplacement mechanisms of plutons within tectonic settings are described and these show that, in general, space for magma can be created by the combination of tectonically-created cavities and internal magma-related buoyancy. This occurs in both transcurrent and extensional tectonic settings and there is no reason to doubt that it can happen in compressive-contractional regimes. It is concluded that transient and permanent space creation, such as may be exploited by available magmas, is a typical feature of the tectonically stressed and deforming lithosphere and this, in combination with the natural buoyancy and ascending tendency of magmas, can generate the varied emplacement mechanisms of granites.

Is there a relation between locus of control orientation and depression

Abstract: Meta-analytic techniques were used to review studies of the relation between locus of control and depression. Contrary to what some authors have claimed, we found that locus of control orientation and degree of depression were significantly related, that the relation was moderately strong, and that it was consistent across studies. Greater externality was associated with greater depression. Studies that included separate subscales for locus of control for positive and negative outcomes produced similar results. Seven potential mediators of the locus of control-depression relation were investigated, with only two producing significant results. Effect sizes varied as a function of the particular locus of control and depression scales used in studies. The implications of the findings are discussed, with special attention given to the \"depressive paradox\" hypothesis (Abramson & Sackeim, 1977) and to Lament's (1972a, 1972b) methodological critique of the locus of control-depression relation.

Resonance absorption of compressible magnetohydrodynamic waves at thin “surfaces”

Abstract: The behavior of plasma and fields in the transition layer supporting MHD surface waves is analyzed, assuming that the total pressure fluctuations, delta-P(tot), can be taken to be nearly constant across this thin transition layer, with a value nearly the same as would be obtained if the MHD wave were supported by a truly discontinuous surface Regarding therefore delta-P(tot) as known, the plasma and field equations in the transition layer were cast into a form in which delta-P(tot) appeared as a driving term Among the two resonances that appear (the cusp resonance and the Alfven resonance) special attention is given to the Alfven resonance, which affects the velocity and magnetic field components normal to the background magnetic field The effects of three types of viscosity on the Alfven resonance are considered, and it is shown that energy is pumped out of the surface wave into thin layers surrounding the resonant field lines

A recalibration of the interstellar ammonia thermometer

Abstract: Les coefficients de vitesse pour l'excitation rotationnelle de para-NH 3 et ortho-NH 3 par para-H 2 (J=0) sont presentes pour les temperatures cinetiques 15≤T≤300 K Les resultats sont utilises pour recalibrer le thermometre ammoniac pour une variete de transitions d'inversion-rotation

July temperatures in europe from pollen data, 6000 years before present.

Abstract: Mean July temperatures across Europe 6000 years before present were reconstructed from palynological data by the transfer function method. Reconstructed summer temperatures were warmer than those at present over most of Europe with the greatest heating, more than 2°C, in the midcontinent and the far north. This pattern is explained by high summer insolation and a weak zonal insolation gradient 6000 years before present and the effective heating of the landmass relative to ocean and coastal areas. A strong land-sea pressure gradient may in turn have increased westerly air flow into southern Europe, which is consistent with cooler reconstructed summer temperatures in the Mediterranean region, and reduced the environmental lapse rate in the central European mountains.

The Durham/Anglo-Australian telescope faint galaxy redshift survey.

Abstract: Presentation des premiers resultats d'une etude spectroscopique d'environ 200 galaxies mesurees en utilisant le coupleur a fibre optique FOCAP du telescope anglo-australien. La strategie de l'etude et les techniques d'observation et de reduction des donnees sont discutees. La distribution du redshift observee est comparee avec les predictions d'un modele. Les spectres des galaxies faibles sont compares a ceux obtenus dans une etude des galaxies brillantes. Une activite de formation stellaire est decouverte dans quelques-unes des galaxies etudiees; les implications sont discutees et un nouveau modele d'evolution des galaxies, compatible avec le denombrement et les distributions des redshifts aux limites faibles est presente

Behavioral momentum and the partial reinforcement effect

Abstract: Nouvelle analyse des contradictions entre la resistance au changement en fonction du taux de renforcement et l'effet de plus grande resistance a l'extinction d'un comportement instrumental partiellement renforce

Tectonics and hydrogeology of the northern Barbados Ridge: Results from Ocean Drilling Program Leg 110

Abstract: Drilling near the deformation front of the northern Barbados Ridge cored an accretionary prism consisting of imbricately thrusted Neogene hemipelagic sediments detached from little-deformed Oligocene to Campanian underthrust deposits by a decollement zone composed of lower Miocene to upper Oligocene, scaly radiolarian claystone. Biostrati-graphically defined age inversions define thrust faults in the accretionary prism that correlate between sites and are apparent on the seismic reflection sections. Two sites located 12 and 17 km west of the deformation front document continuing deformation of the accreted sediments during their uplift. Deformational features include both large- and small-scale folding and continued thrust faulting with the development of stratal disruption, cataclastic shear zones, and the proliferation of scaly fabrics. These features, resembling structures of accretionary complexes exposed on land, have developed in sediments never buried more than 400 m and retaining 40% to 50% porosity. A single oceanic reference site, located 6 km east of the deformation front, shows incipient deformation at the stratigraphic level of the decollement and pore-water chemistry anomalies both at the decollement level and in a subjacent permeable sand interval. Pore-water chemistry data from all sites define two fluid realms: one characterized by methane and chloride anomalies and located within and below the decollement zone and a second marked solely by chloride anomalies and occurring within the accretionary prism. The thermogenic methane in the decollement zone requires fluid transport many tens of kilometers arcward of the deformation front along the shallowly inclined decollement surface, with minimal leakage into the overlying accretionary prism. Chloride anomalies along faults and a permeable sand layer in the underthrust sequence may be caused by membrane filtration or smectite dewatering at depth. Low matrix permeability requires that fluid flow along faults occurs through fracture permeability. Temperature and geochemical data suggest that episodic fluid flow occurs along faults, probably as a result of deformational pumping.

Nursery Crimes: Sexual Abuse in Day Care

Abstract: Introduction, Study Design, and Incidence - David Finkelhor and Linda Meyer Williams Perpetrators - David Finkelhor and Linda Meyer Williams Victims - David Finkelhor Dynamics of Abuse - David Finkelhor Disclosure and Detection - Nanci Burns, David Finkelhor and Linda Meyer Williams Victim Impact - Nanci Burns, Linda Meyer Williams and David Finkelhor Program Risk Factors - Michael Kalinowski and Linda Meyer Williams with Karen Gartner Investigation - Linda Meyer Williams and David Finkelhor Licensing and Criminal Justice System Intervention - Linda Meyer Williams Community Impact - David Finkelhor and Nanci Burns Summary and Recommendations for Parents and Professionals - David Finkelhor and Linda Meyer Williams

Stimulant treatment for the neurobehavioural sequelae of traumatic brain injury

Abstract: The subject of stimulant treatment for patients with neurobehavioural sequelae of traumatic brain injury (TBI) has received a good deal of recent attention, although there have to date been no controlled studies published. This is a description of 15 TBI patients who received treatment with the psychostimulant methylphenidate, in a double-blind, placebo-controlled cross-over study, with behavioural and neuropsychological ratings. Three subjects remained on the drug for a year after the acute study, and were subsequently studied in a double-blind, placebo-controlled reversal. The results support the idea that at least some symptomatic improvement may be gained from low-dose stimulant treatment, although the statistical analysis of the data was compromised by the occurrence of carryover effects from one drug condition to another. This, in itself, is an interesting discovery, because such effects have never been observed in stimulant studies of other patient groups. There are clear implications for the design of further studies in this area. The long-term effects of methylphenidate treatment were not at all impressive, however. Although the findings presented below may be subject to differing interpretation, it is conceivable that stimulants act to advance the course of cortical recovery following TBI.

Transition region, corona, and solar wind in coronal holes: some two-fluid models

Abstract: A model is presented which treats the heating of the corona and the heating and acceleration of the solar wind as a single process, namely, the turbulent dissipation of solar-generated Alfven waves at the Kolmogorov rate. This model is similar to that described by Hollweg (1986), except that the electron temperature and the proton temperature are allowed to have different values. It is found that, similar to the findings of Hollweg, solutions which yield base pressures in the observed range lead to solar wind flows which are much too slow at 1 AU; a new feature is the appearance of proton temperature peak near 3-4 solar radii. Thus, this model seems to be also unsatisfactory. Several possible resolutions are discussed.

Ti plasmid-specified chemotaxis of Agrobacterium tumefaciens C58C1 toward vir-inducing phenolic compounds and soluble factors from monocotyledonous and dicotyledonous plants.

Abstract: Twelve phenolic compounds with related structures were analyzed for their ability to act as chemoattractants for Agrobacterium tumefaciens C58C1 and as inducers of the Ti plasmid virulence operons. The results divided the phenolic compounds into three groups: compounds that act as strong vir inducers and are chemoattractants for A. tumefaciens C58C1 harboring the nopaline Ti plasmid pDUB1003 delta 31, but not the isogenic cured strain; compounds that are at best weak vir inducers and are weak chemoattractants for Ti plasmid-harboring and cured A. tumefaciens C58C1; and compounds that are vir noninducers and are also nonattractants. A strong correlation between vir-inducing ability and Ti plasmid requirement for chemotaxis is thus established. In addition, chemical structure rules for vir induction and chemotaxis are outlined. Positive chemotaxis toward root and shoot homogenates from monocotyledonous and dicotyledonous plants was observed. At low extract concentrations, chemotaxis was enhanced by the presence of Ti plasmid. The chemoattractants do not derive from intact cell walls. Lack of attraction is not responsible for the apparent block to monocot transformation by A. tumefaciens.

Foreign Language Education and Cultural Studies.

Abstract: Some basic definitional and theoretical issues concerning the role of cultural studies in foreign language teaching are discussed. The paper is critical of the tourist‐consumer model of intercultural contact and of the agnostic or minimalist approaches to cultural studies often associated with allegedly culture‐free classifications of language functions. Assumptions of some existing approaches to cultural studies are examined. Four key areas for further work on cultural studies are identified, (1) definition, (2) didactics, (3) teaching methodology, and (4) assessment. Three needs of cultural studies are discussed, (1) an adequate conceptualisation of human culture in social and psychological terms, for which the paper proposes a social anthropological approach, (2) guidelines for research, and (3) a programme of teacher training. The paper concludes with a theoretical model of cultural studies.

Dark and visible matter in spiral galaxies

Abstract: Rotation-curve profiles are used to determine the dark-to-luminous mass ratio within the disk size for 43 spiral galaxies. It is noted that faint galaxies are halo-dominated and that bright galaxies are disk-dominated in the disk regions. The luminosity sequence is shown to be a dark-to-luminous sequence. By removing the dark-matter contribution from the velocity at the disk edge, the dispersion affecting the luminosity-kinematics relation is found to decrease in comparison with the conventional Tully-Fisher correlation.

Geochemical evidence for plume—mantle interactions beneath Kerguelen and Heard Islands, Indian Ocean

Abstract: Within-plate ocean island basalts probably originate by the partial melting of upwelling plumes coming from deep within the Earth's mantle1. Part of the observed heterogeneity in Sr, Nd and Pb isotopic ratios in oceanic basalts may result from the interaction of plumes with the lithosphere 2–4. and asthenosphere2, 5. Kerguelen and Heard Islands, in the southern Indian Ocean, are the latest products of a large and long-lived plume system6, comparable to the Hawaiian–Emperor chain in the Pacific. Kerguelen Island began forming ∼40 Myr ago on the Antarctic plate, near to the embryonic Southeast Indian Ridge (SEIR), and represents the continuation of the hotspot activity preserved on the Indian plate as the Ninety east Ridge7 (Fig. 1). With continuing sea-floor spreading, younger volcanism on Kerguelen has occurred further away from the influence of the SEIR. Here we show that the isotopic compositions of Kerguelen basalts vary in sympathy with this changing tectonic environment, and suggest not only that depleted asthenosphere, but also that Cretaceous oceanic plateau litho-sphere, may have contributed significantly to the earlier magmatic history of the island.

Igneous emplacement in a shear-zone termination: The biotite granite at Strontian, Scotland

Abstract: Deformed xenolith (strain) data together with other structural information indicate that the biotite granite body (∼90 sq km) of the Strontian complex, Scotland, was emplaced in the extensional termination of a dextral transcurrent shear zone. This shear zone is a splay of the major Great Glen fault which lies along the southern boundary of the granite. Siting of the shear zone splay was probably controlled by (a) a slight releasing bend in the Great Glen fault in this area and (b) a large, pre-existing, asymetric synform in Proterozoic metasedimentary country rocks which intersects the Great Glen fault trace at a high angle. A model is proposed in which Moine Thrust (Caledonian) compression at ca. 435 Ma activated the Great Glen fault dextrally. Dextral movements around the releasing bend detached a flat segment from the inside fault wall, and the biotite granite was emplaced side-ways at depths of about 15 km as a sheet into this extensional, listric-fault-bounded, cavity.

Method of building solder bumps

Abstract: The invention is a method of forming a solder bump on an under bump metallurgy in which a contact pad on a substrate material is partially covered by a passivation layer upon the substrate material which is non-wettable by solder and in which the under bump metallurgy covers the portions of the contact pad which are not covered by the passivation layer and in which the under bump metallurgy overlaps from the contact pad to cover portions of the passivation layer. The method comprises depositing a layer of solder soluble metal upon the under bump metallurgy so as to cover the under bump metallurgy with the solder soluble metal; coating the deposit of solder soluble metal with a layer of solidified solder while substantially avoiding complete dissolution of the solder soluble metal in the solder; and heating the solder until the layer of solder melts and the deposit of solder soluble metals substantially completely dissolves in the melted solder and the surface tension of the melted solder draws the solder and dissolved solder soluble metal away from the non-wettable passivation layer and into a spheroid solder bump.

Spectral analysis interpretation of electro-surgical generator nerve and muscle stimulation

Abstract: The frequency spectra of two commercial electrosurgical generators were examined during stimulated tissue cutting and compared to radio-frequency animal nerve and muscle stimulation curves generated from high-frequency sinusoidal current. During electrosurgical cutting, significant energy can exist at the fundamental frequency, as well as at frequencies lower and greater than the fundamental, which may be stimulatory to both nerve and muscle tissue. Different types of biological loads did not seem to significantly affect the spectra of each individual electrosurgical unit (ESU). However, the interaction of a specific ESU output with the biological load when compared to a pure resistive load accounts for varying impedances and resultant modulations of the fundamental frequency. Reducing electrosurgical side effects and hazards may depend, in part, on a better understanding of these underlying mechanisms. >