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Showing papers by "Lancaster University published in 1994"


Journal ArticleDOI
TL;DR: In this paper, specific absorption coefficients for individual carotenoids and chlorophylls a and b, as well as the E 1% 1cm values for combined carotensoids, have been (re)estimated using 6 solvents (80 % acetone, chloroform, diethyl ether, dimethyl formamide and methanol) using two different types of spectrophotometer (0.1-0.5 nm and 1-4 nm band pass resolution).

4,156 citations


Journal ArticleDOI
01 Feb 1994-Nature
TL;DR: In this paper, a simple technique for measuring trace-metal concentrations in situ in water is described, where an ion exchange resin is separated from the solution by an ion-permeable gel membrane.
Abstract: RELIABLE measurement of trace species in natural waters is essential for studies of pollution or trace-element cycling, but is difficult, partly because the distribution of chemical species often changes during sampling and storage1. In situ measurements can overcome these problems, but the few measurements made previously have involved complicated systems that cannot be used routinely1,2. Here we describe a simple technique for measuring trace-metal concentrations in situ in water. The technique incorporates an ion-exchange resin separated from the solution by an ion-permeable gel membrane. Mass transport through the gel is diffusion-controlled and thus well defined, making it possible to obtain quantitative data on concentration and speciation over relatively short time periods (from one hour to several weeks). We present measurements of zinc concentrations in sea water using this technique which agree well with electrochemical measurements. In principle, our technique should be applicable to any inorganic or organic diffusing species.

1,140 citations


Journal ArticleDOI
TL;DR: In this paper, a model combining a multivariate linear model for the underlying response with a logistic regression model was proposed for continuous longitudinal data with non-ignorable or informative dropout.
Abstract: A model is proposed for continuous longitudinal data with non-ignorable or informative drop-out (ID). The model combines a multivariate linear model for the underlying response with a logistic regression model for the drop-out process. The latter incorporates dependence of the probability of drop-out on unobserved, or missing, observations. Parameters in the model are estimated by using maximum likelihood (ML) and inferences drawn through conventional likelihood procedures. In particular, likelihood ratio tests can be used to assess the informativeness of the drop-out process through comparison of the full model with reduced models corresponding to random drop-out (RD) and completely random processes

1,034 citations


Journal ArticleDOI
TL;DR: Investigation of chaotic inflation models with two scalar fields, such that one field (the inflaton) rolls while the other is trapped in a false vacuum state, finds that false vacuum inflation occurs with the inflaton field far below the Planck scale, making it easier to implement in the context of supergravity than standard chaotic inflation.
Abstract: We present a detailed investigation of chaotic inflation models which feature two scalar fields such that one field (the inflaton) rolls while the other is trapped in a false vacuum state. The false vacuum becomes unstable when the magnitude of the inflaton field falls below some critical value, and a first or second order transition to the true vacuum ensues. Particular attention is paid to the case termed ``hybrid inflation'' by Linde, where the false vacuum energy density dominates so that the phase transition signals the end of inflation. We focus mostly on the case of a second order transition, but treat also the first order case and discuss bubble production in that context for the first time. False-vacuum-dominated inflation is dramatically different from the usual true vacuum case, both in its cosmology and in its relation to particle physics. The spectral index of the adiabatic density perturbation originating during inflation can be indistinguishable from 1, or it can be up to ten percent or so higher. The energy scale at the end of inflation can be many orders of magnitude less than the value ${10}^{16}$ GeV, which is ususal in the true vacuum case. Reheating occurs promptly at the end of inflation. Cosmic strings or other topological defects are almost inevitably produced at the end of inflation, and if the inflationary energy scale is near its upper limit they contribute significantly to large scale structure formation and the cosmic microwave background anisotropy.Turning to particle physics, false vacuum inflaton occurs with the inflaton field far below the Planck scale and is therefore somewhat easier to implement in the context of supergravity than true vacuum chaotic inflation. The smallness of the inflaton mass compared with the inflationary Hubble parameter still presents a difficulty for generic supergravity theories. Remarkably, however, the difficulty can be avoided in a natural way for a class of supergravity models that follow from orbifold compactification of superstrings. This opens up the prospect of a truly realistic superstring-derived theory of inflation. One possibility, which we show to be viable at least in the context of global supersymmetry, is that the Peccei-Quinn symmetry is responsible for the false vacuum.

1,033 citations


Journal ArticleDOI
01 Jun 1994-Memory
TL;DR: Findings from the Children's Test of Nonword Repetition are shown to be consistently higher and more specific than those obtained between language skills and another simple verbal task with a significant phonological memory component, auditory digit span.
Abstract: This article presents findings from the Children's Test of Nonword Repetition (CNRep). Normative data based on its administration to over 600 children aged between four and nine years are reported. Close developmental links are established between CNRep scores and vocabulary, reading, and comprehensive skills in children during the early school years. The links between nonword repetition and language skills are shown to be consistently higher and more specific than those obtained between language skills and another simple verbal task with a significant phonological memory component, auditory digit span. The psychological mechanisms underpinning these distinctive developmental relationships between nonword repetition and language development are considered.

918 citations


Journal ArticleDOI
TL;DR: The authors compared a discrete-time approximation of a popular diffusion model with ARCH models for daily DM/exchange rates from 1978 to 1990, and found that the models make different assumptions about how the magnitude of price responses to information alters volatility and the amount of subsequent information.
Abstract: Diffusion models for volatility have been used to price options while ARCH models predominate in descriptive studies of asset volatility. This paper compares a discrete-time approximation of a popular diffusion model with ARCH models. These volatility models have many siimilarities but the models make different assumptions about how the magnitude of price responses to information alters volatility and the amount of subsequent information. Several volatility models are estimated for daily DM/ exchange rates from 1978 to 1990.

635 citations


Proceedings ArticleDOI
22 Oct 1994
TL;DR: A number of ways in which ethnography has been used to inform design are identified and the benefits and problems of each are considered.
Abstract: Ethnography has gained considerable prominence as a technique for informing CSCW systems development of the nature of work. Experiences of ethnography reported to date have focused on the use of prolonged on-going enthnography to inform systems design. A considerable number of these studies have taken place within constrained and focused work domain. This paper reflects more generally on the experiences of using ethnography across a number of different projects and in a variety of domains of study. We identify a number of ways in which we have used ethnography to inform design and consider the benefits and problems of each.

627 citations


Journal ArticleDOI
David Otley1
TL;DR: The traditional definition of the scope and practice of management control which was developed in the mid 1960s is now too restrictive as it is based on a context of large, hierarchically structured organizations which are now in relative decline as discussed by the authors.

615 citations


Journal ArticleDOI
TL;DR: In this article, the authors consider the role of the ELT textbook in terms of its normal day-to-day use in teaching and learning English, and then consider its role in the process of change.
Abstract: Why does there appear to be apathy and even hostility to the ELT textbook in the literature? Why does it survive and prosper apparently in contradiction to the development of ideas in applied linguistics? In this paper, we first consider the role of the textbook in terms of its normal dayto-day use in teaching and learning English, and then consider its role in the process of change. We refer to data from a study carried out in the Philippines into the introduction of an ESP textbook. In the light of our analysis, we challenge some of the assumptions that underlie the antitextbook view. We argue that the textbook has a vital and positive part to play in the everyday job of teaching and learning English, and that the importance of the textbook becomes even greater in periods of change. Finally, we considerthe implications of a more informed and positive view of the role of the textbook, emphasizing, in particular, the need to see textbook creation and teacher education as complementary and mutually beneficial aspects of professional development.

528 citations


Journal ArticleDOI
TL;DR: In this paper, the follow-up at age 15 of a group of children who were diagnosed at age 5 as having delayed motor development was reported, and the control group still differed in motor performance 10 years later: 46% of the members of the early motor delay group were classified as different on motor and perceptual tasks.
Abstract: This paper reports the follow-up at age 15 of a group of children who were diagnosed at age 5 as having delayed motor development. The group of children who were clumsy and the control group still differed in motor performance 10 years later: 46% of the members of the early motor delay group were classified as different from the control group on motor and perceptual tasks. The remainder made up an intermediate group that could not be clearly distinguished from the other groups. Adolescents with stable motor problems had fewer social hobbies and pastimes and had lower academic ambitions for their future than the controls, although the lower academic ambitions also reflect their lower academic achievements. The adolescents who were clumsy believed they were less physically and scholastically competent than the controls. However, they did not have poor opinions of their social acceptance or self-worth. The intermediate group, although they showed motor delay at age 5, had good school performance and high amb...

430 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied six large newly industrializing countries (NICs) in the 1950s and found that the most well-endowed NICs abandoned AIP early in favor of a competitive industrial policy (CIP) which relied on labor-intensive exports to earn foreign exchange and resulted in rapid economic growth.

Journal ArticleDOI
TL;DR: There were equal numbers of males and females within each of the two groups with arithmetic difficulties but a preponderance of males over females amongst the group with specific reading difficulties.
Abstract: Data from an epidemiological sample (n= 1206) of British schoolchildren were used to estimate the proportions of 9- to 10-year-olds with specific arithmetic difficulties (SAD), combined with arithmetic-and-reading difficulties (ARD), and specific reading difficulties (SRD). Children in the sample contributed scores on saparate tests of arithmetic reading and nonverbal intelligence. Using a cutting-store approach, which took into account performance on all three tests, a small group of children with SAD (1.3 %) were distinguished from tarter groups with ARD (2.3%) and SRD (3.9%). Contrary to some previous reports, there were equal numbers of males and females within each of the two groups with arithmetic difficulties but a preponderance of males over females amongst the group with specific reading difficulties.

Journal ArticleDOI
TL;DR: It is concluded that the case study method can be useful in a wide variety of contexts, but that greater clarity is needed in that way such work is written-up so that maximum benefit is gained.

Journal ArticleDOI
TL;DR: The authors demontre qu'il faudrait reconsiderer la negligence des etudes historiques de la science populaire and de la popularisation en fonction de l'hegemonie de la sciences elle-meme.
Abstract: L'A. demontre qu'il faudrait reconsiderer la negligence des etudes historiques de la science populaire et de la popularisation en fonction de l'hegemonie de la science elle-meme

Journal ArticleDOI
TL;DR: In this article, a theoretical treatment of the ascent, emplacement, and eruption of magma on Mars is presented, showing that the lower gravity, fluid convective motions and crystal settling processes driven by positive and negative buoyancy forces, as well as overall diapiric ascent rates, will be slower on Mars than on Earth, permitting larger diapirs to ascend to shallower depths.
Abstract: We present a theoretical treatment of the ascent, emplacement, and eruption of magma on Mars. Because of the lower gravity, fluid convective motions and crystal settling processes driven by positive and negative buoyancy forces, as well as overall diapiric ascent rates, will be slower on Mars than on Earth, permitting larger diapirs to ascend to shallower depths. Martian environmental conditions operate to modulate the various eruption styles and the morphology and morphometry of resulting landforms, providing new insight into several volcanological problems.

Journal ArticleDOI
TL;DR: Critica1 examination of the ABA-signaling hypothesis must show that enough extra ABA moves in the transpiration stream to the shoots to account for the changes in functioning that are recorded.
Abstract: We have known for many years that the dehydration of plant cells can lead to accumulation of the plant growth regulator ABA. Application of this compound to well-watered plants mimics many of the effects of soil drymg on gene expression, physiology, growth, and development, making this compound a strong candidate for a role in the droughted plant. Dehydration of leaves can result in massive accumulations of ABA, and roots also synthesize the compound in increased amounts as they are exposed to drier and drier soil. Davies and Zhang (1991) argued that an important component of the drought responses of many plants can be an ABA signal moving from the roots to the shoots to regulate physiology and development as a function of soil water status/availability. Many recent reports show relationships between stomatal conductance and soil water status or xylem ABA concentration, which seem to support this view. Nevertheless, critica1 examination of the ABA-signaling hypothesis must show that enough extra ABA moves in the transpiration stream to the shoots to account for the changes in functioning that are recorded. Many other chemicals moving in the xylem to shoots can also provide shoots with 'information" conceming root functioning, and we must consider the nature of such signals. We should also be concemed with the nature of the information that might be transmitted by a root signal (eg. a measure of soil water status or soil water availability) and the form that such a chemical signal might take (e.g. the concentration of the signal molecule in the transpiration stream or the flux of signal molecules to the site of action in the leaf).

Journal ArticleDOI
TL;DR: In this paper, the authors apply univariate extreme value theory to quantify the risk of failure due to extreme levels of some environmental process and demonstrate how these ideas can be exploited as part of the design process.
Abstract: For many structural design problems univariate extreme value theory is applied to quantify the risk of failure due to extreme levels of some environmental process. In practice, many forms of structure fail owing to a combination of various processes at extreme levels. Recent developments in statistical methodology for multivariate extremes enable the modelling of such behaviour. The aim of this paper is to demonstrate how these ideas can be exploited as part of the design process

Journal ArticleDOI
TL;DR: Under conditions of high light and low nutrient availability, AM infection can alter the carbon/nutrient balance of plants, leading to an increased allocation to carbon-based defences and this can have important consequences for insect herbivore performance and the patterns of herbivory in field situations.
Abstract: summary A field experiment was conducted to investigate whether infection by arbuscular mycorrhizal (AM) fungi has any effect on herbivory by foliar-feeding insects. Plants of PI ant ago laureolata L. were grown in a randomized block design and natural levels of mycorrhizal infection reduced by the application of the granular fungicide iprodione. Plant growth responses were examined and herbivore bioassays performed by rearing both a chewing and sucking insect on the leaves of mycorrhizal and fungicide-treated plants. Fungicide application successfully reduced mycorrhizal infection, and this led to reductions in foliar biomass, caused by lower leaf number. However, fungicide-treated plants suffered consistently higher levels of damage by centralist chewing and leaf-mining insects, which colonized the plants. The chewing insect bioassay confirmed the field results, in that larvae of Arttia caja L. (Lepidoptera: Arctiidae) consumed more leaf material from plants in which infection was reduced. There was no evidence that AM fungi altered food quality for the chewing insect. Instead, infection caused an increase in the carbon/nutrient balance, which in turn led to increased levels of the carbon-based feeding deterrents, aucubin and catalpol, The sucking insect, Mvzus perskae (Sulzer) reacted in an opposite fashion to the ehewtr. with performance being greater on mycorrhizal plants. Again, there was no evidence that an alteration in food Quality was the cause, and in this case infection may result in changes in leaf morphology which benefit the insect. We suggest that under conditions of high light and low nutrient availability. AM infection can alter the carbon/nutrient balance of plants, leading to an increased allocation to carbon-based defences. This can have important consequences for insect herbivore performance and the patterns of herbivory in field situations.

Journal ArticleDOI
TL;DR: In this article, a semidistributed version of TOPMODEL has been applied to the Real Collobrier experimental basin (71 km2 in southeast France with 21 recording raingauges) using an hourly time step and a series of independent events.

Journal ArticleDOI
TL;DR: In this article, a study of addictive consumption in the UK was conducted, where individual depth interviews with 15 women were followed by a mail survey of a further 46 self-identified addictive shoppers.
Abstract: This article reports on a study of addictive consumption in the UK. Individual depth interviews with 15 women were followed by a mail survey of a further 46 self-identified addictive shoppers. The study suggests that the behaviour serves a variety of functions for the individual and that there is no simple uniform picture of an addictive shopper. Prime functions of the behaviour are to repair mood, and to increase the ability to match perceptions of socially desirable or required appearances. The behaviour is located in the context of postmodern fragmentation, in which personal identity is manifested in a reliance on affect-charged experiences. Links are made with other aspects of consumption pathology.

Journal ArticleDOI
TL;DR: The results are interpreted within a framework in which active spatial attention is involved in maintaining spatial items in order in memory, and is interfered with by any task (visual, auditory, perceptual, motor) that also makes demands on spatial attention.
Abstract: It has been suggested that maintenance in visuospatial immediate memory involves implicit motor processes that are analogous to the articulatory loop in verbal memory. An alternative account, which is explored here, is that maintenance is based on shifts of spatial attention. In four experiments, subjects recalled spatial memory span items after an interval, and in a fifth experiment, digit span was recalled after an interval. The tasks carried out during the interval included touching visual targets, repeating heard words, listening to tones from spatially separated locations, pointing to these tones, pointing to visual targets, and categorizing spatial targets as being from the left or right. Spatial span recall was impaired if subjects saw visual targets or heard tones, and this impairment was increased if either a motor response or a categorical response was made. Repeating words heard in different spatial locations did not impair recall, but reading visually presented words did interfere. For digit span only, the tasks involving a verbal response impaired recall. The results are interpreted within a framework in which active spatial attention is involved in maintaining spatial items in order in memory, and is interfered with by any task (visual, auditory, perceptual, motor) that also makes demands on spatial attention.

Journal ArticleDOI
TL;DR: The first author's data-based mechanistic (DBM) approach to model structure identification and parameter estimation for linear and non-linear dynamic systems and uses it to explore afresh the non- linear relationship between measured rainfall and flow in two typical catchments.
Abstract: Although rainfall-flow processes have received much attention in the hydrological literature, the nature of the non-linear processes involved in the relationship between rainfall and river flow still remains rather unclear. This paper outlines the first author's data-based mechanistic (DBM) approach to model structure identification and parameter estimation for linear and non-linear dynamic systems and uses it to explore afresh the non-linear relationship between measured rainfall and flow in two typical catchments. Exploiting the power of recursive estimation, state dependent non-linearities are identified objectively from the time series data and used as the basis for the estimation of non-linear transfer function models of the rainfall - flow dynamics. These objectively identified models not only explain the data in a parametrically efficient manner but also reveal the possible parallel nature of the underlying physical processes within the catchments. The DBM modelling approach provides a useful tool for the further investigation of rainfall-flow processes, as well as other linear and non-linear environmental systems. Moreover, because DBM modelling uses recursive estimation, it provides a powerful vehicle for the design of real-time, self-adaptive environmental management systems. Finally, the paper points out how DBM models can often be interpreted directly in terms of dynamic conservation equations (mass, energy or momentum) associated with environmental flow processes and stresses the importance of parallel processes in this connection.

Journal ArticleDOI
TL;DR: In this article, a non-isothermal Bingham flow model is proposed to compute the channel and levee width of a flow and hence permits the advance rates of flows and their maximum cooling-limited lengths for different gradients and effusion rates to be calculated.
Abstract: Factors which control lava flow length are still not fully understood. The assumption that flow length as mainly influenced by viscosity was contested by Walker (1973) who proposed that the length of a lava flow was dependent on the mean effusion rate, and by Malin (1980) who concluded that flow length was dependent on erupted volume. Our reanalysis of Malin's data shows that, if short duration and tube-fed flows are eliminated, Malin's Hawaiian flow data are consistent with Walker's assertion. However, the length of a flow can vary, for a given effusion rate, by a factor of 7, and by up to 10 for a given volume. Factors other than effusion rate and volume are therefore clearly important in controlling the lengths of lava flows. We establish the relative importance of the other factors by performing a multivariate analysis of data for recent Hawaiian lava flows. In addition to generating empirical equations relating flow length to other variables, we have developed a non-isothermal Bingham flow model. This computes the channel and levee width of a flow and hence permits the advance rates of flows and their maximum cooling-limited lengths for different gradients and effusion rates to be calculated. Changing rheological properties are taken into account using the ratio of yield strength to viscosity; available field measurements show that this varies systematically from the vent to the front of a lava flow. The model gives reasonable agreement with data from the 1983–1986 Pu'u ‘O’o eruptions and the 1984 eruption of Mauna Loa. The method has also been applied to andesitic and rhyolitic lava flows. It predicts that, while the more silicic lava flows advance at generally slower rates than basaltic flows, their maximum flow lengths, for a given effusion rate, will be greater than for basaltic lava flows.

Journal ArticleDOI
TL;DR: The dramatic fall in PCB levels in archived UK soils and vegetation between the mid-1960s and the present is evidence that the latter mechanism is the most important and that a significant proportion of PCBs released into the UK environment in the 1960s have subsequently undergone environmental transport away from the UK.

Journal ArticleDOI
TL;DR: In this paper, Ash (Fraxinus excelsior L.), birch (Betula pubescens Ehrh), sycamore (Acer pseudoplatanus L.) and Sitka spruce (Picea sitchensis (Bong.) Carr.) leaf litters were monitored for decomposition rates and nutrient release in a laboratory microcosm experiment.
Abstract: Ash (Fraxinus excelsior L.), birch (Betula pubescens Ehrh.), sycamore (Acer pseudoplatanus L.) and Sitka spruce (Picea sitchensis (Bong.) Carr.) leaf litters were monitored for decomposition rates and nutrient release in a laboratory microcosm experiment. Litters were derived from solar domes where plants had been exposed to two different CO2 regimes: ambient (350 μL L-1 CO2) and enriched (600 μL L-1 CO2). Elevated CO2 significantly affected some of the major litter quality parameters, with lower N, higher lignin concentrations and higher ratios of C/N and lignin/N for litters derived from enriched CO2. Respiration rates of the deciduous species were significantly decreased for litters grown under elevated CO2, and reductions in mass loss at the end of the experiment were generally observed in litters derived from the 600 ppm CO2 treatment. Nutrient mineralization, dissolved organic carbon, and pH in microcosm leachates did not differ significantly between the two CO2 treatments for any of the species studied. Litter quality parameters were examined for correlations with cumulative respiration and decomposition rates: N concentration, C/N and lignin/N ratios showed the highest correlations, with differences between litter types. The results indicate that higher C storage will occur in soil as a consequence of litter quality changes resulting from higher atmospheric concentrations of CO2.

Journal ArticleDOI
24 Mar 1994-Nature
TL;DR: In this paper, it has been shown that a symmetry-breaking phase transition occurred via the Higgs mechanism about 10−34 after the Big Bang as the universe cooled through a critical temperature of 1027 K. This transition may have generated defects in the geometry of space-time (such as cosmic strings), which provided the inhomogeneities on which galaxies subsequently condensed.
Abstract: ALTHOUGH the birth of the Universe is inaccessible to experimental study, aspects of cosmological theories can nonetheless be explored in the laboratory. Tiny inhomogeneities in the mix of particles and radiation produced in the Big Bang grew into the clusters of galaxies that we see today, but how those inhomogeneities arose and grew is still unclear. Cosmologies based on grand unified theories suggest that a symmetry-breaking phase transition occurred via the Higgs mechanism about 10−34 after the Big Bang as the Universe cooled through a critical temperature of 1027 K. It has been proposed by Kibble1 that this transition may have generated defects in the geometry of space-time (such as cosmic strings), which provided the inhomogeneities on which galaxies subsequently condensed. Zurek2–4 has suggested that it might be possible to model this cosmological phase transition by a laboratory analogue, the superfluid transition of liquid 4He induced by fast adiabatic expansion through the critical density. Here we report the results of such an experiment. We observe copious production of quantized vortices5, the superfluid analogue of cosmic strings. These results support Kibble's contention that such defects were available in the early Universe to seed galaxy formation.

Proceedings ArticleDOI
Dan Shapiro1
22 Oct 1994
TL;DR: This paper addresses some of the divergences between social sciences, and proposes the development of hybrid forms of participation in CSCW with discussion of some issues in two areas: the cognitive versus the ethnographic; it further describes the politics of participation.
Abstract: This paper addresses some of the divergences between social sciences, and proposes the development of hybrid forms of participation in CSCW. It offers a critique of the theoretical isolationism of some ethnomethodological ethnography. It reviews the prospects for interdisciplinary collaboration, and seeks to motivate it with some “core propositions” which expose the inescapable character of the problems (although not necessarily of the solutions) which are “owned” by different disciplines. It illustrates hybrid forms with discussion of some issues in two areas: the cognitive versus the ethnographic; it further describes the politics of participation.

Proceedings ArticleDOI
05 Aug 1994
TL;DR: The main purpose of this paper is to describe the CLAWS4 general-purpose grammatical tagger, used for the tagging of the 100-million-word British National Corpus, and emphasise the goals of adaptability, incorporation of linguistic knowledge to improve quality, consistency, and accuracy.
Abstract: The main purpose of this paper is to describe the CLAWS4 general-purpose grammatical tagger, used for the tagging of the 100-million-word British National Corpus, of which c.70 million words have been tagged at the time of writing (April 1994)) We will emphasise the goals of (a) gener~d-purpose adaptability, (b) incorporation of linguistic knowledge to improve quality ,and consistency, and (c) accuracy, measured consistently and in a linguistically informed way. The British National Corpus (BNC) consists of c.100 million words of English written texts and spoken transcriptions, sampled from a comprehensive range of text types. The BNC includes 10 million words of spoken h'mguage, c.45% of which is impromptu conversation (see Crowdy, forthcoming). It also includes ,an immense variety of written texts, including unpublished materials. The gr,'unmatical tagging of the corpus has therefore required the 'super-robustness' of a tagger which can adapt well to virtually all kinds of text. The tagger also has had to be versatile in dealing with different tagsets (sets of grammatical category labels-see 3 below) and accepting text in varied input formats. For the purposes of the BNC, l, he tagger has been requircd both to accept and to output text in a corpus-oriented TEl-confonnant mark-up definition known as CDIF (Corpus Document Interchange Format), but within this format many variant fornaats (affecting, for example, segmentation into words and sentences) can be readily accepted. In addition, CLAWS al-

Journal ArticleDOI
TL;DR: In this article, the temporal and the social dimensions of market exchange are considered, particularly those between organizations, which are embedded in a social framework which rewards continuity and predictability, respectively.
Abstract: Two important, although neglected, dimensions of market exchange are the temporal and the social. Exchanges, particularly those between organizations, may be thought of as embedded in a social framework which rewards continuity. Similarly exchanges between the same entities which recur over time take on a different character from those which are instantaneous and atomistic. Such patterns of exchange create a framework, of among other things, expectations, trust, adaptations and investments which can be said to comprise the elements of a relationship. Addresses the many reasons why individuals, but especially organizations, choose to give up freedom of choice and the open market for the confines of a stable and long‐term relationship. Where such relationships exist they provide a measure of continuity in the workings of markets. This, in turn, gives rise to enduring structures which have been labelled industrial networks. Such structures provide an important framework for exchanges within a market since th...

Journal ArticleDOI
TL;DR: A conditional approach to inference is developed which converts the point process model to a non-linear binary regression model for the spatial variation in risk for a specified disease in relation to possible environmental factors.
Abstract: SUMMARY We consider the problem of investigating the elevation in risk for a specified disease in relation to possible environmental factors. Our starting point is an inhomogeneous Poisson point process model for the spatial variation in the incidence of cases and controls in a designated geographic region, as proposed by Diggle. We develop a conditional approach to inference which converts the point process model to a non-linear binary regression model for the spatial variation in risk. Simulations suggest that the usual asymptotic approximations for likelihood-based inference are more reliable in this conditional setting than in the original point process setting. We present an application to some data on the spatial distribution of asthma in relation to three industrial locations.