Showing papers by "University of Warwick published in 1987"

Context and Action in the Transformation of the Firm

Abstract: The article focuses on the context and action in the transformation of the firm. The article addresses James MacGregor Burns's assertion that effective leadership is evident by the achievement of real and intended change. The author claims that change leadership can only be measured over time and must consider multiple perspectives, taking into account continuity and change, individual as well as group actions, and patterns and idiosyncracies. The article reviews the current literature on change leadership, presents a longitudinal study of strategic change processes at Imperial Chemical Industries, and interprets the findings of the study.

On scale mixtures of normal distributions

Abstract: SUMMARY The exponential power family of distributions of Box & Tiao (1973) is shown to be a subset of the class of scale mixtures of normals. The corresponding mixing distributions are explicitly obtained, identifying a close relationship between the exponential power family and a further class of normal scale mixtures, namely the stable distributions.

Strategy or Structure? Capital, Labour and Control

Abstract: The literature on and for management makes increasing use of notions of strategy. Is such an approach compatible with analyses of capitalism as structurally determined? The first part of the paper ...

Cyclic homology and equivariant homology

Abstract: The purpose of this paper is to explore the relationship between the cyclic homology and cohomology theories of Connes [9-11], see also Loday and Quillen [20], and "IF equivariant homology and cohomology theories. Here II" is the circle group. The most general results involve the definitions of the cyclic homology of cyclic chain complexes and the notions of cyclic and cocyclic spaces so precise statements will be postponed until w 3. In this introduction we explain some of the formal similarities between the cyclic theory and the equivariant theory and give two examples where the general results apply. Let A be an associative algebra over a commutative ring K. Then one can form the cyclic homology HC.(A) and cohomology HC*(A) of A. These groups have periodicity operators

The long‐term survival of Escherichia coli in river water

Abstract: Escherichia coli introduced into autoclaved filtered river water survived for up to 260 d at temperatures from 4 degrees to 25 degrees C with no loss of viability. Survival times were less in water which was only filtered through either a Whatman filter paper or a 0.45 micron Millipore filter or in untreated water, suggesting that competition with the natural microbial flora of the water was the primary factor in the disappearance of the introduced bacteria. Survival was also dependent upon temperature with survival at 4 degrees C greater than 15 degrees C greater than 25 degrees C greater than 37 degrees C for any water sample. Direct counts showed that bacterial cells did not disappear as the viable count decreased. The possession of the antibiotic resistance plasmids, R1drd-19 or R144-3, did not enhance survival nor cause a faster rate of decay, indicating that the metabolic burden imposed by a plasmid was not a factor in survival under starvation conditions. There was no evidence of transfer of either plasmid at 15 degrees C or of loss of plasmid function during starvation.

Epidemiology and control of virus diseases of vegetables

Abstract: SUMMARY The diverse ecological and epidemiological factors which determine virus infection of vegetable crops are discussed. These include the sources and spread of viruses, together with some agricultural and horticultural practices which have influenced their prevalence. Control measures are described, demonstrating ways of avoiding or minimising infection. Developments are reported with insecticides, insect repellents, anti-feedants, and fungicides for the control of virus vectors. Some of the successes and future requirements in breeding vegetable cultivars with virus resistance are listed. An Appendix lists the economically most important vegetable virus diseases present in 28 countries or regions with temperate, Mediterranean-like or subtropical climates. The five most important viruses in field-grown vegetables are transmitted non-persistently by aphids (cucumber mosaic, turnip mosaic, potato virus Y, lettuce mosaic and watermelon mosaic 1 (= papaya ringspot virus)). In contrast, with protectively-grown vegetables, the most important are the mechanically-transmitted tobamoviruses (tomato and tobacco mosaic, Capsicum mosaic and cucumber green mottle mosaic).

Accounting for accounting: Towards the development of a dialectical view

Abstract: This paper questions the adequacy of current approaches to accounting research. Following a re-examination of the progress made by the interpretive perspective in correcting for many of the shortcomings in the traditional framework, a catalogue of unresolved problems and silences is constructed. It is argued that central to this is the persistent failure adequately to contextualize accounting whilst at the same time treating it as a fully social practice. The second part of the paper is accordingly devoted to the development and illustration of an alternative, fuller, perspective. This, it is claimed, contains the potential to allow a deeper understanding of the linkages between routinized practices and conflicts and the socio-economic contexts in which they are located.

The linear quadratic control problem for infinite dimensional systems with unbounded input and output operators

Abstract: This paper establishes a general semigroup framework for solving quadratic control problems with infinite dimensional state space and unbounded input and output operators.

Application of Just‐in‐Time Manufacturing Techniques in the United Kingdom

Abstract: There is widespread interest and discussion of Just‐in‐Time (JIT) manufacturing but little is known about the actual uptake and pattern of use of JIT and its constituent techniques. This article reports the results of a survey of UK manufacturing companies. The survey examined the level of consideration of JIT in the UK, the nature of the JIT effort, the JIT techniques used and not used, the effectiveness of the various techniques and the benefits reported from JIT. The data are reviewed by industry, sector, size and parent company and conclusions are developed concerning the nature of the application of JIT in the UK. The data indicate that though the overall level of interest in JIT is high, there are a number of causes for concern in the way in which it is being implemented.

Relative Efficiency Assessments Using Data Envelopment Analysis: An Application to Data on Rates Departments

Abstract: This paper examines the nature of information obtained from data envelopment analysis (DEA) in comparative studies of the efficiency of decision-making units, and it discusses the interpretation and practical usefulness of such information The themes developed in the paper are illustrated by an application of DEA to data on the rate-collection function of London Boroughs and Metropolitan District Councils The paper begins with an overview of DEA, followed by a discussion of some of the practical considerations arising in the application of DEA It then describes the structuring of the rate-collection function for assessment by DEA, and explores the extent to which units can be classified as relatively efficient or inefficient In respect of relatively inefficient units, it illustrates the construction of target inputs and outputs so that their relative efficiency may improve In respect of relatively efficient units, it is argued that their identification is weak in the sense that for some of them their apparent efficiency may be simply a reflection of an uncommon input-output profile It is shown, nevertheless, that information about relatively efficient units can be used to identify those of them which may prove examples of good operating practice in given aspects of their function (Readers not familiar with British taxes may wish to note that rates are a tax on property, levied by local authorities)

Sensors and actuators in distributed systems

Abstract: The concepts of strategic sensors and actuators are introduced for a class of distributed parameter systems This emphasizes the spatial structure and location of the sensors and controls in order that observability and controllability can be achieved

Collective Bargaining Arrangements, Closed Shops and Relative Pay

Abstract: This paper uses establishment-level data to examine the impact on union/nonunion pay differentials of the industrial relations setting in which bargaining takes place. The pre-entry closed shop is found to be of prime importance for the pay of both skilled and semiskilled manual workers. For skilled workers, and for semiskilled workers in larger establishments, the differentials are found to be insignificantly different from zero in the absence of a pre-entry closed shop. Copyright 1987 by Royal Economic Society.

Evaluation of a simulation model for prediction of herbicide movement and persistence in soil

Abstract: Summary The movement and persistence of residues of propyzamide, linuron, isoxaben and R-40244 were measured in a sandy loam soil in field experiments prepared in spring and autumn. None of the herbicides moved to depths greater than 12 cm in the soil during the winter period, following application in autumn, and none moved more than 6 cm in the soil, following application in spring. The general order of persistence of total soil residues was isoxaben > linuron = R-40244 > propyzamide. Appropriate constants to describe the moisture and temperature dependence of degradation were derived from laboratory incubation experiments and used with measurements of the strengths of adsorption of the different herbicides by the soil, in a computer model of herbicide movement. The model, in general, gave good predictions of total soil residues, but overestimated herbicide movement, particularly in winter. Measurements of herbicide desorption from the soil at intervals, during a laboratory incubation experiment, demonstrated an apparent increase in the strength of adsorption with time. When appropriate allowance was made for these changes in adsorption in the computer model, improved predictions of the vertical distribution of the herbicide residues were obtained. Resume Evaluation d'un modele de simulation pour la prevision du mouvement et de la persistance d'un herbicide dans le sol Le mouvement et la persistance des residus de propyzamide, linuron, isoxaben et fluorochloridone ont ete mesures en sol sablo-argileux dans des champs experimentaux prepares en automne et au printemps. Aucun des herbicides n'a atteint une profondeur de plus de 12 cm pendant la periode hivernale suivant une application automnale, et de plus de 6 cm apres une application de printemps. L'ordre general de la persistence des residus dans le sol etait isoxaben > linuron = R-40244 > propyzamide. Des constantes appropriees pour decrire la dependance da la degradation vis-a-vis de l'humidite et de la temperature ont decoule d'experimentations de laboratoire et ont ete utilisees avec les mesures des quantites absorbees des differents herbicides par le sol, dans un modele informatique concernant le mouvement des herbicides. En general, le modele a donne une bonne precision des quantites globales de residus, mais en revanche, a surestime le mouvement des herbicides, en particulier pendant l'hiver. Des mesures de la description des herbicides a partir du sol, par intervalles, pendant l'experimentation de laboratoire ont montre un acroissement important de la force de l'adsorption avec le temps. Quand des deductions appropriees etaient faites pour prendre en compte ces phenomenes d'adsorption dans le modele informatique, on a obtenu des previsions ameliorees de la distribution verticale des residus d'herbicides. Zusammenfassung Beurteilung eines Simulationsmodells fur die Vorhersage der Herbizideinwaschung und -persistenz im Boden Einwaschung und Persistenz von Propyzamid, Linuron, Isoxaben und R-40244-Ruckstanden wurden im Freiland in einem sandigen Lehmboden nach Fruhjahrs- und Herbst-Applikation gemessen. In keinem Fall konnte eine Einwaschung nach Herbst-Applikation tiefer als 12 cm und nach Fruhjahrs-Applikation tiefer als 6 cm nachgewiesen werden. Im allgemeinen war die Persistent der Gesamtruckstande im Boden: Isoxaben > Linuron = Fluorchloridon > Propyzamid. Die Konstanicn zur Beschreibung des Einflusses von Feuchtigkeit und Temperatur auf den Abbau wurden aus Laborexperimenten abgeleitet. Diese Daten wurden in Verbindung mil Messungen der Adsorptionsstarke der verschiedenen Herbizide im Boden in einem Computer-Modell neben der Vorhersage der Persistenz auch zur Beschreibung des Einwaschungsverhaltens verwendet. Das Gesamt-Modell erlaubt eine gute Vorhersage der Persistenz. uberbewertet aber die Einwaschung, vor allem im Winter. Messungen der Desorption bei den Laborversuchen in verschiedenen Intervallen zeigten eine offensichtliche Zunahme der Adsorption mit der Zeit, deren Berucksichtigung im Modell zu einer verbesserten Vorhersage der vertikalen Verteilung der Herbizide fuhrte.

Image Segmentation and Uncertainty

Abstract: From the Publisher: Presents the first unified theory of image segmentation, written by the winners of the 1985 Pattern Recognition Society medal Until now, image processing algorithms have always been beset by uncertainties, no one method proving completely satisfactory Wilson and Spann tackle the problem of uncertainty head-on They describe a new class of algorithms (based, in part, on quadtrees) and demonstrate their applications, including grey level and texture segmentation These algorithms produce excellent results in a wide range of synthetic and natural data Provides many examples of applications from medicine to remote sensing

Anomalous structural behavior of the superconducting compound La1.85Ba0.15CuO4.

Abstract: High-resolution neutron powder diffraction experiments on the superconducting compound ${\mathrm{La}}_{1.85}$${\mathrm{Ba}}_{0.15}$Cu${\mathrm{O}}_{4}$ have revealed the presence of a tetragonal-to-orthorhombic phase transition at 180 K, together with subtle, anomalous structural instabilities at lower temperatures. These experiments demonstrate a correlation between the structural anomalies and changes in the electrical resistivity.

Simple x-ray standing-wave technique and its application to the investigation of the Cu(111) ( √3 √3 )R30 ° -Cl structure

Abstract: A new variant of the usual x-ray standing-wave experiment, scanning the Bragg reflection in energy at normal incidence, is shown to be applicable to metal crystals without special precautions being taken to ensure high crystalline perfection. The structure of the Cu(111)(\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{}-Cl chemisorption phase is found to be compatible with the results of a previous surface extended x-ray-absorption fine structure and photoelectron diffraction study.

Dealing with Inherent Variability: The Difference Between Manufacturing and Service?

Abstract: The debate about whether any difference exists between manufacturing and service operations is discussed. There is no difference per se between the two types of operation and that debate about differences between them is spurious. There are significant differences between operating systems which process materials and those which deal directly with customers. These differences are sufficient to require different treatment for material processing operations and customer processing operations. The similarities and differences between the two types of system are demonstrated, and strategies for managing customer processing operations are outlined. If an appropriate strategy is adopted, customer processing operations are very similar to material processing operations, but other strategies exist which make customer processing operations very different from material processing operations.

Six-coordinated silicon in glasses

Abstract: It has been accepted since 1932 that the building block of silicate glasses consists of silicon tetrahedrally coordinated to 4 oxygen atoms1 Although the existence of 6-coordinated silicon in a few crystalline materials, such as stishovite, and SiP2O7 is known2,3, the presence of (SiO6) units has not yet been observed experimentally in glasses Recent X-ray diffraction and magic-angle-spinning (MAS) nuclear magnetic resonance investigations4,5 of SiO2-P2O5 glasses found only 4-coordinated silicon although SiP2O7 was produced by devitrification Raman studies6 of Na2O-SiO2-P2O5 glasses were interpreted as indicating the presence of a structural unit containing Si-O-P bonding but otherwise unidentifiable We have applied MAS nuclear magnetic resonance spectroscopy to similar glasses and here we report the first observation of [SiO6] units in glasses

Dissociation of the ribulosebisphosphate-carboxylase large-subunit binding protein into dissimilar subunits.

Abstract: The ribulosebisphosphate-carboxylase large-subunit binding protein from Pisum sativum chloroplasts is an oligomer of two types of subunit with the composition alpha 6 beta 6. These two subunits are immunologically distinct, show different partial protease digestion patterns and have different amino-terminal sequences. Leaves of Hordeum vulgare also contain an oligomeric binding protein composed of equal amounts of two types of subunit. Treatment of either P. sativum stromal extracts or purified binding protein with ATP and Mg2+ ions causes the dissociation of the oligomeric form of the binding protein to the monomeric subunits. This effect is highly specific for ATP since CTP, UTP, GTP, ADP, AMP, cyclic AMP, NADPH and pyrophosphate do not cause dissociation.

A more expressive formulation of many sorted logic

Abstract: Many sorted logics can increase deductive efficiency by eliminating useless branches of the search space, but usually this results in reduced expressiveness. The many sorted logic described here has several unusual features which not only increase expressiveness but also can reduce the search space even more than a conventional many sorted logic. The quantifiers are unsorted: the restriction on the range of a variable derives from the argument positions of the nonlogical symbols that it occupies. Polymorphic sort specifications are allowed; thus statements usually requiring several assertions may be compactly expressed by a single assertion. The sort structure may be an arbitrary lattice and the sort of a term can be more general than the sort of the argument position it occupies. It is also shown how it is sometimes possible to use sort information to determine the truth value of a formula without resort normal inference. Inference rules for a resolution based system are discussed; these can be proved to be sound and complete.

Improved Sorting Networks with O(log n) Depth

Abstract: The sorting network described by Ajtaiet al was the first to achieve a depth ofO(logn) The networks introduced here are simplifications and improvements based strongly on their work While the constants obtained for the depth bound still prevent the construction being of practical value, the structure of the presentation offers a convenient basis for further development

The influence of soil properties on the rates of degradation of metamitron, metazachlor and metribuzin

Abstract: The rates of degradation of metamitron, metazachlor and metribuzin were measured in 12 mineral soils and the first order rate constants were compared with soil properties by regression analysis. Rates of metamitron degradation were best described by a multiple regression involving the silt content of the soil and the fraction of the total herbicide content which was available in the soil solution. Metazachlor degradation was best described by a multiple regression involving the sand content of the soil, the availability of the herbicide in the soil solution and soil microbial respiration. There was evidence that metribuzin degradation in any one soil was closely related to microbial activity, and rate constants per unit microbial respiration were derived for each soil. These rate constants were best described by a multiple regression involving the Freundlich adsorption constant and the sand content of the soils. The best regression equations for each herbicide were tested against observed degradation rates in an additional group of six soils. The calculated rates compared favourably with those observed for both metamitron and metazachlor, but with metribuzin, there was good agreement with one soil only.