Showing papers by "Lancaster University published in 1976"

Grain size variations in ignimbrites and implications for the transport of pyroclastic flows

Abstract: Ignimbrite flow units commonly show reverse grading of large pumice clasts and normal grading of large lithic clasts. Ignimbrites show coarse-tail grading, in which particles beneath a critical diameter, ranging from 64 to 2 mm, are ungraded. Above this size the larger the clast diameter the more pronounced the segregation. The grading is consistent with the theoretical settling rates of particles in a dispersion with a high particle concentration. Ignimbrite flow units show a reversely graded, fine grained basal layer which is attributed to the action of boundary forces during flow. Ignimbrites are commonly associated with cross-stratified pyroclastic surge deposits and fine ash fall deposits formed in the same eruption. The fine ash fall deposit is depleted in crystals and is thought to be the deposit of the fine turbulent cloud observed making up the upper parts of nuees ardentes. Pyroclastic flows are postulated to be dense, poorly expanded partly fluidized debris flows. Only its fine grained components can be fluidized by gas. Pyroclastic flows are believed to behave as a dispersion of larger clasts in a medium of fluidized fines, which acts as a lubricant similar to water in mud-flows. Poor sorting in ignimbrites is attributed to high particle concentrations not turbulence. Many pyroclastic flows may be laminar in their movement with apparent viscosities, deduced from the lateral grading of large lithic clasts, in the range 101−103 poise.

The expected value of the adjusted rescaled Hurst range of independent normal summands

Abstract: SUMMARY Hurst's empirical law concerning geophysical time series such as annual river flows was framed in terms of an adjusted rescaled range, namely, the range of cumulative sums of deviations of summands from a linearly time-shifted origin, expressed in units of the estimated standard deviation of the full sample. Nonsimulatory theoretical results of the Hurst phenomenon have hitherto been confined to the adjusted range, without rescaling. The present paper derives the expectation of the adjusted rescaled range for independent normal summands.

Classification and formation of lava levees on Mount Etna, Sicily

Abstract: Observations of the 1975 subterminal lava flows and sections through the larger flank lavas on Mount Etna show that there are four principal types of levees formed in Etnean lavas: initial, accretionary, rubble, and overflow. Initial levees are formed because of the yield strength of these non-Newtonian lavas and are thought to determine channel width. The other types of levees are formed subsequently and are built up over the rarely preserved initial levees. Mechanisms of formation of each levee type vary; most levees are hybrids of two or more of the four types. We also discuss the prospects of deducing lava rheology from morphology and the application of this technique to surfaces of other planets.

The Nature, Use and Acquisition of Managerial Skills and other Attributes

Abstract: This paper is concerned with two questions: 1 What are the kinds of skills and other qualities in managers that contribute to managerial success and performance in various forms? 2 To what extent are these acquired by learning, and what are the sources of such learning? The aim is to propose and test a general framework or taxonomy describing what managers might need to learn, and to understand from where existing managers have acquired the skills and qualities they currently use. This further allows us to draw some conclusions about the part played by deliberate training and education activities, in comparison with ‘natural’ ones, in the development of managers. The paper considers and reports in turn on existing theories and research relevant to managerial qualities, a hypothetical model of such qualities, an empirical test of the models, and the results of a study of the sources involved in the acquisition of specific qualities contributing to successful management actions in a sample of managers.

The Open Field

Abstract: The paper attempts to define an epistemology of process as a basis for the development of expressive and creative action. Five conditions of process are identified-unstructured action, change, projectability, the situation, the abstract field-and their behavioral implications are discussed. Finally, a methodology for the personal use of process is presented.

Liquid and solid helium

Abstract: The Physics of Liquid and Solid Helium. Part 1. (Interscience Monographs and Texts in Physics and Astronomy, Vol. 29.) by K. H. Bennemann and J. B. Ketterson, Pp. 589. (Wiley-Interscience: New York and London, June 1976.) $35.35; £21.

The Cutting Stock Problem in the Flat Glass Industry - Selection of Stock Sizes

Abstract: In the glass industry holding good stock sizes appears to have at least as big an impact on trim loss as cutting up the stock plates efficiently. In this paper two tech niques are described for determining "optimal" stock sizes, one a heuristic method and the other an integer programming algorithm. Several actual applications within the glass industry are described, and illustrative results of the improvements in wastage that have been achieved are given.

Liberia and Sierra Leone: An Essay in Comparative Politics

Abstract: 1. Political Comparison 2. Historical Summary 3. Resources 4. Rules 5. Political Allocation at the Centre 6. Centre and Periphery 7. Aspects of Political Economy 8. Concluding Review.

Performance and Instability in Military and Nonmilitary Regime Systems

Abstract: The analysis of military regimes, as opposed to military coups, has attracted comparatively little attention. This paper examines whether the political, military, and economic performance of systems which have experienced a military regime differs from the performance of systems which have not. The comparison between the performance of these two types of system is then used to examine the validity of the occurrence of a military regime as an indicator of instability. The population consists of all independent countries of the world. The time span examined is 1961–70. The comparison is made across a number of political, military, and economic variables. The basic comparison is elaborated by introducing controls for GNP, area, number of coups, and duration of the military regime. While the controls show a number of variations, the main summary finding is that it is easy to differentiate military and non-military regime systems in political terms, but not in military and economic terms. This finding seriously questions the utility of the occurrence of a military regime as an indicator of instability.

Methodological Choices in Depot Location Studies

Abstract: Following a brief introduction indicating that the literature on depot location is extensive, seven choices that face the analyst are discussed When choosing the objective the choice is between cost minimization or return-on-assets criteria The potential locations can be anywhere (an infinite set) or restricted to a feasible set The search procedure employed may be an optimizing one or a heuristic The planning horizon needs to be determined The location of current depots may or may not be built into the formulation of the model and the model may or may not include depot capacities Finally, the modelling of local delivery costs is discussed

Fine structure of the dogfish egg case: a unique collagenous material.

Abstract: The fine structure of the dogfish egg case is described with special reference to the highly ordered, unique, collagen-containing fibrils. The outer layer of the case wall contains densely packed, amorphous granules, rich in tyrosine while approximately 98% of the thickness of the case is built up from orthogonally stacked laminae of closely packed, collagen-containing fibrils. These fibrils show a paracrystalline three-dimensional construction. A model for the structure of the B band of the fibril is proposed, based on appearances in transverse sections of different thickness and on two projections seen in longitudinal sections. The transverse projection of the unit cell appears to be a square lattice with sides approximately 110 A possibly containing a pseudocell with sides 110 4 A. The structure of these fibrils is discussed in relation to those of rat tail tendon collagen.

A restriction on the topology of Cauchy surfaces in general relativity

Abstract: It is shown that, in a globally hyperbolic and geodesically complete space-time, a part of a partial Cauchy surface that is bounded by a uniformly convex sphere is compact and simply connected.

Knowledge, perception and memory

Abstract: What do you do to start reading knowledge perception and memory? Searching the book that you love to read first or find an interesting book that will make you want to read? Everybody has difference with their reason of reading a book. Actuary, reading habit must be from earlier. Many people may be love to read, but not a book. It's not fault. Someone will be bored to open the thick book with small words to read. In more, this is the real condition. So do happen probably with this knowledge perception and memory.

Petrochemistry of the Early Carboniferous (Dinantian) Lavas of Scotland

Abstract: Synopsis This review is focussed on the early Carboniferous (Dinantian) stage of the complex Carboniferous-Permian volcanic cycle in central and southern Scotland (The “Midland Valley petrographic province”). Stress is particularly laid on aspects of the petrochemistry and petrogenesis not previously recognized or sufficiently discussed in the literature. The scarcity of analytical data for rocks from critical parts of the province means that much of the discussion must be of a preliminary nature; areas where further research is required are indicated. The Dinantian lavas, dominated by a range of mildly undersaturated and hypersthene-normative (transitional) alkaline basalts, have associated nepheline or hypersthene-normative hawaiites, mugearites, benmoreites, quartz-trachytes and rhyolites. Several geographically distinct magmatic lineages are recognized, varying in such parameters as degree of silica undersaturation, Fe/Mg ratios and Na 2 O/K 2 O ratios at comparable values of differentiation index. TiO 2 and P 2 O 5 contents also vary from suite to suite. The proportions of each lava type are variable in different areas, but three volcanic associations are rather arbitrarily distinguished; one showing a spectrum of rocks from ankaramitic basalt to trachytes and rhyolites: a second dominated by plagioclase-phyric basalts and hawaiites: and thirdly, an association consisting largely of olivine-clinopyroxene-phyric basalts, with more differentiated rocks scarce or absent. Though data are very scarce for post-Dinantian lavas, it is suggested that there has been a progressive change in basic magma chemistry with time during the Carboniferous, later alkaline magmas being increasingly silica-undersaturated. This change was accompanied by a change in the nature of the volcanism, which became more explosive, tuffs and agglomerates representing an increasing proportion of the eruptive products. Some aspects of the petrogenesis of the Dinantian basic lavas are examined. A high-pressure (>10 kb) stage of fractionation variably involving clinopyroxene or olivine + clinopyroxene is required to explain the chemical variation in the basalts and hawaiites. More differentiated rocks may have evolved by crystal fractionation at lower pressures (within crustal magma reservoirs?) but insufficient data are available to test this hypothesis.

Arctic Coccolithophorids: Two Species of Turrisphaera gen.nov. from West Greenland, Alaska, and the Northwest Passage

Abstract: Turrisphaera gennov is characterized by an unusual type of calcification in which small hexagonal crystallites, shaped like perforated plates or rings, are reticulately arranged within an organic matrix responsible for the tubular or tower-like coccolith morphology T borealis spnov, the type species which is described, has been found living in very cold water (-1 degrees C) in the middle of the Northwest Passage as well as near the adjacent oceans at each end where the sea temperature is higher In the coldest locality (Resolute Bay), typical T borealis, though present, was outnumbered by deviants described here as a second species, T arctica spnov, perhaps alternatively interpretable as locally induced growth-forms Comparisons with other living and fossil taxa indicate fewer points of resemblance between Turrisphaera and other known coccolithophorids than between it and several species of the wholly unmineralized genus Chrysochromulina Finally the geographical distribution suggests that in this particular case the Northwest Passage could be a significant migration route from the Pacific to the Atlantic Ocean

Effect of infection by microsphaera alphitoides (powdery mildew) on carbohydrate levels and translocation in seedlings of quercus robur

Abstract: SUMMARY As infection of leaves of Quercus robur by Microsphaera alphitoides (powdery mildew) progressed, levels of total carbohydrate varied as first the rate of net photosynthesis declined and then an abnormal pattern of translocation was established. Infected leaves exported a smaller proportion of their photosynthate than did healthy leaves and imported a greater proportion of the photosynthate of healthy leaves on the same plant than did healthy leaves on healthy plants. Infection caused a decrease in the amounts of sucrose and insoluble glucose and an increase in amounts of glucose and fructose in leaf tissue. Evidence is presented that glucose and fructose were transferred to the fungus where they were converted to polyhydric alcohols and trehalose.

Chemical control of stomatal movements

Abstract: Artificially induced partial closure of stomata can improve the efficiency with which plants use available water; in other words, there is a fall in the transpiration: photosynthesis ratio The careful use of some metabolic inhibitors can achieve the required inhibition of stomatal opening, but properly controlled application under field conditions is difficult and metabolic inhibition of photosynthesis in the mesophyll can occur In the search for a more specific inhibitor of the activities of stomatal guard cells, most attention has been focused on abscisic acid, a hormone which appears to function as an endogenous regulator of stomatal opening External application of abscisic acid achieves a useful reduction in the transpiration: photosynthesis ratio Studies are being made of the effects of chemical analogues of abscisic acid in the search for more active compounds Another naturally occurring substance which induces stomata to close, all- trans -farnesol, has been found in water-stressed sorghum plants Sorghum is better able to tolerate water shortage than most crops, and further studies of its physiological mechanisms should lead to a better understanding of how we can provide protection for more susceptible crops

The usefulness of residual income

Abstract: There is still a controversy over the use of residual income as a tool for the measurement of the performance of units and managers in divisionalized organizations. This has been highlighted by the recent debate in this journal between Cyril Tomkins [1, 2] and Lloyd Amey [3]. Tomkins advocates the use of residual income for profit centres where control over working capital is vested with the division, although he dismisses it as redundant for full investment centres. Amey specifically denies the appropriateness of residual income in either case. David Solomons [4] originally proposed residual income as a measure capable of separately appraising the performance of both an investment centre and its manager. There is thus wide disagreement as to the validity and usefulness of residual income. The objective of this note is to outline the practical and theoretical benefits and limitations of the residual income concept as a means of appraising performance in divisionalized organizations.

Doctors in Casualty: Applying Communicative Competence to Components of Specialist Course Design.

Abstract: Les auteurs de manuals pour l'enseignement des langues negligent souvent de prendre en consideration les futurs besoms communicatifs de leu r s eleves. Le besoin de materiaux pedagogiques adequats aux different* buts poursuivis par 1'enseignant est par consequent fortement senti. On ne satisfait pourtant pas a ce besoin avant d'avoir decrit 1'usage linguistique valable dans des situations clairement precisees. Les auteurs de cet article essaient de caracteriser le langage utilise entre les medecins et ieurs clients victimes d'accidents.

Valleys and settlement: Some new evidence

Abstract: Extensive field survey in South Etruria (central Italy) has revealed little evidence for valley‐bottom settlement. This is partly explained by an overlay of recent silt but was caused principally by periodic valley flooding, for which a climatic explanation is likely. Settlement evidence is mainly restricted to the period before the sixth century B.C. and the first and second centuries A.D. A number of low‐lying English sites in valley and fenland contexts also demonstrate a similar sequence.