Showing papers by "University of Exeter published in 1986"

Grounded Theory and Organizational Research

Abstract: Grounded theory is an inductive, theory discovery methodology that allows the researcher to develop a theoretical account of the general features of a topic while simultaneously grounding the account in empirical observations or data (Glaser & Strauss, 1967). This article explicates the utility of a grounded theory approach to research on work organizations. Following a general introduction to the grounded theory method, the authors'review of the organizational literature using grounded theory illustrates the variety of issues and topics studied through this approach. The authors describe and explain specific strategies for conducting grounded theory research in and on organizations, including note taking and note writing, concept discovery, and concept definition and preliminary elaboration of theory. Throughout the article emphasis is placed on grounded theory's ability to facilitate understanding and to identify desirable improvements in work contexts.

Models of man

Abstract: Feel lonely? What about reading books? Book is one of the greatest friends to accompany while in your lonely time. When you have no friends and activities somewhere and sometimes, reading book can be a great choice. This is not only for spending the time, it will increase the knowledge. Of course the b=benefits to take will relate to what kind of book that you are reading. And now, we will concern you to try reading models of man as one of the reading material to finish quickly.

The nonlinear development of Gortler vortices in growing boundary layers

Abstract: The Growth of Gortler vortices in boundary layers on concave walls is investigated. It is shown that for vortices of wavelength comparable to the boundary-layer thickness the appropriate linear stability equations cannot be reduced to ordinary differential equations. The partial differential equations governing the linear stability of the flow are solved numerically, and neutral stability is defined by the condition that a dimensionless energy function associated with the flow should have a maximum or minimum when plotted as a function of the downstream variable X. The position of neutral stability is found to depend on how and where the boundary layer is perturbed, so that the concept of a unique neutral curve so familiar in hydrodynamic-stability theory is not tenable in the Gortler problem, except for asymptotically small wavelengths. The results obtained are compared with previous parallel-flow theories and the small-wavelength asymptotic results of Hall (1982a, b), which are found to be reasonably accurate even for moderate values of the wavelength. The parallel-flow theories of the growth of Gortler vortices are found to be irrelevant except for the small-wavelength limit. The main deficiency of the parallel-flow theories is shown to arise from the inability of any ordinary differential approximation to the full partial differential stability equations to describe adequately the decay of the vortex at the edge of the boundary layer. This deficiency becomes intensified as the wavelength of the vortices increases and is the cause of the wide spread of the neutral curves predicted by parallel-flow theories. It is found that for a wall of constant radius of curvature a given vortex imposed on the flow can grow for at most a finite range of values of X. This result is entirely consistent with, and is explicable by the asymptotic results of, Hall (1982a).

The hydrodynamic stability of flow over Kramer-type compliant surfaces. Part 2. Flow-induced surface instabilities

Abstract: The flow-induced surface instabilities of Kramer-type compliant surfaces are investigated by a variety of theoretical approaches. This class of instability includes all those modes of instability for which the mechanism of generation involves essentially inviscid processes. The results should be applicable to all compliant surfaces that could be modelled theoretically by a thin elastic plate, with or without applied longitudinal tension, supported on a springy elastic foundation. with or without a viscous fluid substrate; material damping is also taken into account through the viscoelastic properties of the solid constituents of the coatings.The simple case of a potential main flow is studied first. The eigenmodes for this case are subjected to an energy analysis following the methods of Landahl (1962). Instabilities that grow both in space and time are then considered, and absolute and convective instabilities identified and analysed.The effects of irreversible processes on the flow-induced surface instabilities are investigated. The shear flow in the boundary layer gives rise to a fluctuating pressure component which is out of phase with the surface motion. This leads to an irreversible transfer of energy from the main stream to the compliant surface. This mechanism is studied in detail and is shown to be responsible for travelling-wave flutter. Simple results are obtained for the critical velocity, wavenumber and stability boundaries. These last are shown to be in good agreement with the results obtained by the numerical integration of the Orr–Sommerfeld equation. An analysis of the effects of a viscous fluid substrate and of material damping is then carried out. The simpler inviscid theory is shown to predict values of the maximum growth rate which are, again, in good agreement with the results obtained by the numerical integration of the Orr–Sommerfeld equation provided that the instability is fairly weak.Compliant surfaces of finite length are analysed in the limit as wave-length tends to zero. In this way the static-divergence instability is predicted. Simple formulae for critical velocity and wavenumber are derived. These are in exact agreement with the results of the simpler infinite-length theory. But, whereas a substantial level of damping is required for the instability on a surface of infinite length, static divergence grows fastest in the absence of damping on a surface of finite length.

The Psychology of the Near Miss

Abstract: Near misses are widely believed to encourage future play, even in games of chance where the probability of winning remains constant from trial to trial. Some commercial gambling systems, particularly instant lotteries and slot machines, are contrived to ensure a higher frequency of near misses than would be expected by chance alone. Theoretical interpretations and relevant experiments are examined. A distinction is drawn between possible short-term and longer-term effects of manipulating the rate of occurrence of near misses.

suc1 is an essential gene involved in both the cell cycle and growth in fission yeast.

Abstract: The gene suc1 encodes a product which suppresses certain temperature sensitive mutants of the cell cycle control gene cdc2 of Schizosaccharomyces pombe. Mutants in the suc1 gene or over-expression of its product leads to delays in mitotic and meiotic nuclear division. Deletion of the suc1 gene is lethal and generates some cells blocked in the cell cycle and others impaired in cellular growth. It is likely that the suc1 gene product binds and forms unstable complexes with the cdc2 protein kinase and with other proteins necessary for the cell cycle and cellular growth. suc1 may have a regulatory role in these processes.

An Approach to the Mechanics of Pleating in Dragonfly Wings

Abstract: A structural engineering approach to the pleated wings of Odonata has been developed during a functional study of wing morphology in the group. The wing can be regarded as a folded plate structure within which each pleat-side acts as a deep plate-girder. Small cross-veins act as stiffeners within the girders, allowing the membrane to carry web shearing forces as pure tension, through a stressed-skin effect. Bending experiments confirm that the membrane significantly increases the rigidity of wing components. The properties of the membrane are unknown. It lacks birefringence, is very thin, and may be pure epicuticle. The advantages of stressedskin construction are discussed, and possible modes of structural failure considered. The wing seems adapted to yield reversibly to unpredictable heavy loads.

An Asymptotic Investigation of the Stationary Modes of Instability of the Boundary Layer on a Rotating Disc

Abstract: An investigation of high Reynolds number stationary instabilities in the boundary layer on a rotating disc is given. It is shown that in addition to the inviscid mode at high Reynolds numbers, there is a stationary short wavelength mode. This mode has its structure fixed by a balance between viscous and Coriolis forces and cannot be described by an inviscid theory. The asymptotic structure of the wavenumber and orientation of this mode is obtained. A similar analysis is given for the inviscid mode, the expansion procedure used is capable of taking nonparallel effects into account in a self consistent manner. The results are compared to numerical calculations and experimental observations.

Sociological Aspects of Organizational Symbolism

Abstract: not as a sociologist, but as an engineer of sorts, working in engineering shops, gas appliance factories and metallurgical laboratories. Subsequent sociological training helped me to start to make sense of these diverse organizational experiences, and when I re-entered industrial organizations to look with a sociologist’s eye, and to listen with a sociologist’s ear, I felt that I should be concerned to record and to explain the distinctive cultural features of the industrial organization, to outline the different ’context of meaning’ inhabited by those people whom I met and got to know. This attitude created some problems for me, since I was employed on a project which was not explicitly concerned with such matters, since its purpose was to

Fungal endophytes in Salicornia perennis

Abstract: Thirty-two species of endophytic fungi were isolated from the stems of Salicornia perennis . Significant differences were found between colonization of old and new plant tissues. Pleospora salicorniae was found to colonize most parts of the plants whereas Pleospora bjorlingii was mostly confined to old plant tissue. Two species of Stagonospora were largely confined to new plant tissue. A multiple regression model revealed that P. salicorniae , two species of Stagonospora and to a lesser extent Diplodina salicorniae mainly account for the colonization of new tissues. The results are discussed in relation to the ecology of the host and the colonizing fungi.

Predicting Cigarette Use: The Need to Incorporate Measures of Salience in the Theory of Reasoned Action1,2

Abstract: It is shown that incorporating a measure of belief salience in the theory of reasoned action improves both the model's predictive and explanatory power. It is demonstrated that the sum of the five evaluative-beliefs which are most salient for each person is more predictive of a semantic differential measure of that person's attitude than is the sum of the remaining nonsalient evaluative beliefs. In addition, it is shown that the perceived utilities of smoking are differentially salient for smokers and nonsmokers. It is argued that latitude of rejection, centrality, and certainty can be used as measures of the degree of definition of a person's attitudes and subjective norms. It is consequently predicted that these variables will be correlated and that attitudes and subjective norms which are well defined will be more highly predictive of a person's intention and behavior. While some support was found for these hypotheses, it is argued that the present results suggest that the relationship between these variables may be more complicated than was initially hypothesized.

Fungal endophytes in Ulex europaeus and Ulex gallii

Abstract: Three hundred and thirty-nine endophytic isolates were obtained from spines and stems of Ulex europaeus and U. gallii. The incidence of colonization with different endophytes showed a significant tendency to increase with advancing age of the host tissue.

Factors influencing the growth of Attamyces bromatificus, a symbiont of attine ants

Abstract: Investigations of conditions for optimum growth of the attine symbiont Attamyces bromatificus revealed that it was inhibited by light and grew best at temperatures between 20 and 25°C, while temperatures above 30° were lethal. Mean gongylidia size remained small in cultures at 15°. The pH of ant-maintained fungus gardens ranged from 4.35 to 5.00 irrespective of the plant material used and showed a trend of increasing acidity with age. Cultures on buffered PDA solid medium showed maximum yields of gongylidia biomass between pH 4.5 and 5.0. The ant metathoracic gland secretions, β-hydroxydecanoic acid and IAA had only a minor indirect influence on growth through pH regulation. In liquid culture, growth form was atypical and lacked gongylidia. The best indices of fungal growth were those of fresh weight and gongylidia production on solid media.

Intelligent tutoring systems: An overview

Abstract: In this paper we look at the evolutionary development of Computer Assisted Instruction from the early days of ‘linear programs’ up to the use of ‘expert systems’ in education and training. We present the basic principles of Intelligent Tutoring Systems (ITS) which are capable of rich interaction with the student, which know how to teach, and who and what they are teaching. We point out the need for knowledge representation formalisms which can support ITS and present one such formalism (production systems). In the framework presented we describe systems developed for the teaching of modern languages, electronic trouble shooting and computer programming. Finally we point out the shortcomings of ITS and identify areas where a consensus of opinion does not exist. © 1986 Wiley Periodicals, Inc. (Masoud Yazdani: Masoud Yazdani studied Computer Science at the University of Essex and Artificial Intelligence at the University of Sussex. He joined Exeter University in 1980 as a lecturer in Computer Science. His research work is in two areas of computational models of creativity and intelligent tutoring systems. This latter area has led to implementation of various systems using artificial intelligence techniques to teach arithmetic and foreign languages. He is Chairman of Intellect Limited, a company specialising in applications of AI and to educate industry in what AI can offer it. He has acted as a consultant to various industrial companies including Acorn Computers, GTE Inc. and ITT Engineering Support Centre. He is the Committee Secretary for the Society for the Study of Artificial Intelligence and Simulation of Behaviour (AISB). His books include New Horizons in Educational Computing, Artificial Intelligence: Human Effects, both published by Ellis Horwood Ltd. and Artificial Intelligence: Principles and Applications published by Chapman and Hall.)

Abstinence or controlled drinking in clinical practice: a test of the dependence and persuasion hypotheses.

Abstract: Summary Forty-six clients of a clinical psychology service were assigned, in accordance with a three-step design which involved a random element, to abstinence (ABST) or controlled drinking (CD), and were followed up to 12 months after initial assessment. No support was found for the dependence hypothesis: those with higher levels of dependence/severity assigned to CD and those with lower levels assigned to ABST were just as likely as other clients to do well, and there was no relationship between level of dependence/severity and the type of drinking outcome (ABST or CD). There was tentative support for the hypothesis that experience in the follow-up year would be related to initial beliefs and preferences, although these were not independent of treatment type. The present report is not able to comment on the prediction of outcome in the longer term.

Helping agents' attitudes towards alcohol-related problems: situations vacant? A test and elaboration of a model.

Abstract: Summary An elaboration of Cartwright's (1980) model explaining agents' negative attitudes to responding to alcohol-related problems (ARPs) is presented Rather than Role Support, Experience, Education and Self-esteem per se being seen as the main variables with effect on therapeutic attitude, it is argued that the effects of these factors are best viewed as contingent upon situational influences operating within agents' occupational contexts An attempt was made to isolate some of these influences by comparing the work situations of 24 Community Psychiatric Nurses (CPNs) and 24 Social Workers Correlational data suggested that an index of Situational Constraint, although it was not independent of Role Support and Experience, could reliably predict levels of attitudes towards ARPs It was found that CPNs expressed significantly more positive therapeutic attitudes towards drinkers than either ‘long-term’ generic, or medical, Social Workers, but were also working under less Situational Constraint It is concluded that social workers do not attain such deep levels of involvement in ARPs as CPNs owing to their more constraining work environments They are, therefore, less open to ARP educational events and are less likely to develop role support contacts Recommendations for future role support provision and training programmes are briefly outlined

Tax Evasion on the Micro: Significant Simulations or Expedient Experiments?:

Abstract: In recent years various aspects of tax evasion (the effects of tax rates, audit probability and equity) have been investigated using simulation techniques. This paper reports a series of experiments which have looked at the usefulness of this approach. The simulations have all been implemented on a microcomputer. Study 1 attempted to replicate previous findings. The results revealed the higher the audit probability the less tax would be avoided but severity of fine had no effect. Study 2 involved interviewing subjects after they had taken part in a simulation study. Most subjects reported that the simulation was just a game and that their behaviour was unrelated to their ‘real-life’ tax behaviour. What seemed to be crucial was how the situation was defined. Study 3 investigated this directly. When the simulation was described as an “economic problem” subjects behaved more like rational optimisers than when it was described as an “economic game”. It is concluded that for simulations to make a significant c...

Attitudes toward Nuclear Energy: Familiarity and Salience

Abstract: This study examined attitudes toward the building of a nuclear power station in one's locality. In a survey of 719 residents of four small rural communities that were selected as possible locations for a new nuclear power station in southwest England, we examined the effects of having lived near a nuclear power station on perceptions of the various possible consequences associated with this technology. Results showed a more favorable attitude in the community located near the existing nuclear power stations than in the three remaining communities. Experience of having lived near a nuclear power station affected not only respondents' perceptions of the various potential costs and benefits of the building and operation of a nuclear power station in one's locality, but also the importance respondents attached to the various consequences. Results indicated marked differences in perceptions of economic benefits and health and environmental risks. Furthermore, present findings suggest that psychological risks p...

Effect of steroidal glycoalkaloids of the potato on the permeability of liposome membranes

Abstract: At pH 72, the potato glycoalkaloid α-chaconine caused release of entrapped peroxidase from phosphatidylcholine liposomes containing different free sterols but was ineffective against sterol-free liposomes The alkaloid was able to complex with all the tested sterols in vitro although there was no close correlation between the extent of sterol binding and liposome disruption α-Solanine also complexed with sterols in vitro but had no effects on sterol-containing liposomes under these conditions Both sterol concentration and alkaloid concentration were limiting factors in the action of chaconine but did not markedly affect that of solanine Solanine destabilized liposome membranes only at pH values of 8 and above but was less effective than chaconine The importance of the carbohydrate moiety of glycoalkaloids was further demonstrated by the inability of β2-chaconine to complex with sterols or disrupt liposomes

An evaluation of the Defence Mechanism Test

Abstract: A number of applied studies have shown that Kragh's Defence Mechanism Test (DMT) is able to predict success in stressful occupations in accord with Freudian theory. This test has never been related to other common personality measures, and only one study has determined whether subliminal threat is a necessary condition for producing the perceptual distortions thought to correspond to defences. Two experiments are reported. One shows that subliminal threat is a necessary element of the DMT. The second shows that, although the correlations between the DMT scales and established personality variables are generally small, they are as hypothesized from Freudian theory. The lack of correspondence between the repression scale of the DMT and a measure of perceptual defence does however cast doubt on the validity of this scale of the test.

Models of hydrolytic weakening in quartz.

Abstract: Three models of the weakening of quartz by small amounts of water are described and analysed. Attention is confined to the glide of dislocations caused by a double-kink nucleation process. The structure of a double kink on a basal 60 degree dislocation is described and its formation energy estimated using a short-range interaction potential. The same potential was used to give a lower bound to its migration energy. The energies of Griggs-Blacic-Frank and (4H)//S//i models of water bound to kinks are also calculated. The results strongly support these models of hydrolytic weakening.