bluuebunny/crossref_metadata_2025 huggingface dataset:
On the spatial embeddedness of innovation networks: an exploration of the proximity effect
Authors: Oerlemans Leon , Meeus Marius , Boekema Frans
Published: March 2003

The organisational and spatial embeddedness of innovator firms is often taken for granted. This paper develops a theoretical synthesis of regional science (milieu innovateur, systems of innovation) and organisation science (resource and activity‐based perspective) accounting for the proximity effect (benefiting from localised ties). The resulting research models enable us to derive several hypotheses on factors influencing the organisational and spatial embeddedness of innovation networks. Results of OLS and logistic regression analyses, using an unique firm‐level database of 689 manufacturing firms located in the Dutch region of Noord‐Brabant, support most of the hypotheses. First, high levels of complexity of innovative activities induce organisational embeddedness. Second, spatial embeddedness of innovative ties with buyers/suppliers is influenced, in particular, by pre‐existing economic ties of innovating firms and the need for frequent contacts. Findings are, however, sensitive because features of innovative activities differ depending on the position of the innovator firm (user or producer). Therefore, no general explanation of the proximity effect can be found. It turns out that the use of complementary theoretical perspectives is a fruitful way of researching the proximity effect empirically.
The spatial limits to entrepreneurship: Immigrant entrepreneurs in Canada
Authors: Hiebert Daniel
Published: March 2003

Labour market participation and the income of immigrants in the Canadian economy, both as employees and entrepreneurs, is investigated. Special attention is devoted to the situation of those who entered Canada as business immigrants, who have been admitted into the country due to their past accomplishments in managing and establishing businesses in other parts of the world. This programme is based, essentially, on the logic of globalisation, that success in one location can be replicated in another despite different economic and regulatory environments. Using the Canadian Immigration Database, which links the landing records of immigrants with their subsequent tax returns, the economic performance of different types of immigrants to Canada is explored. The data reveal that business immigrants have lower incomes and rates of entrepreneurship than would be expected; in contrast, refugees settling in Canada appear to have higher rates of participation in the Canadian labour market as well as higher incomes. This turn of events suggests that there are critical spatial limits to entrepreneurial success. More precisely, business acumen gained in one location may not apply in another.
Ethnic Segregation in the Netherlands: New Patterns, New Policies?
Authors: Bolt Gideon , Hooimeijer Pieter , Van Kempen Ronald
Published: March 2003

An impressive set of welfare state arrangements has kept ethnic segregation and concentration in Dutch cities to a relatively low level. Indices of segregation have also been relatively stable over the last two decades. This does not mean, however, that concentrations of ethnic minority groups are stable. Some types of neighbourhoods seem to have become less important as housing areas for ethnic minority groups, while others are becoming their main housing areas, especially for Turks and Moroccans. While in some cities this shifting pattern has already been characteristic for more than a decade, in other cities it is of more recent origin. We describe these shifting patterns of ethnic minority groups in the largest cities in the Netherlands (Amsterdam, Rotterdam, The Hague and Utrecht). We then focus on the policy response to these patterns and we briefly evaluate this response. Our main conclusion is that ethnic concentrations are not problematic in themselves, but that policy can significantly enhance the situation of (the inhabitants of) specific neighbourhoods.
The Supply, Use and Quality of Randstad Holland’s Transportation Networks in Comparative Perspective
Authors: Hilbers Hans D. , Wilmink Isabel R.
Published: March 2003

Accessibility is considered a major determinant of the economic competitiveness of metropolitan areas. Comparison with Germany’s Rhine–Ruhr area and Belgium’s Antwerp–Brussels–Ghent region on three accessibility factors may help to put Randstad’s position on this issue into perspective. The supply of transportation infrastructure is analysed by means of an assessment of the density, structure and capacity of the motorways, regional roads, railways and urban rail network. Randstad shows a medium level density of the motorway network, with a relatively low capacity when related to the number of residents within the region. The high number of motorway exits, however, compensates for the limited regional road network. The rail network density in Randstad is also relatively limited. Road and rail networks are used intensively in Randstad, when compared to the other regions. The resulting quality of transportation networks is quite good, but the faster population growth, and the limited remaining capacity and lack of alternative routes questions the future adequacy of these networks.
The internet and home purchase
Authors: Palm Risa , Danis Michelle
Published: March 2003

In the pre–internet era, information was a key determinant of the geographic nature of intra–urban moves. Information was a far more limited commodity, and therefore subject to management and even manipulation. Information brokers, particularly real estate agents, could order and limit the kinds of information to which prospective buyers gained access, with the potential of strongly biasing search space. In the past few years, a vastly enriched information source on housing vacancies has become available through real estate industry–sponsored sites on the internet. This rich information source has the potential to influence spatial patterns and processes in the search for housing by eliminating information barriers in the search process. Three hypotheses were tested with data from Wake County (Rayleigh), North Carolina. First, those with less prior familiarity with the destination area would make more frequent use of the internet. Second, internet users would visit fewer houses personally because they would have more prior information about the market, eliminating the need for some personal home visits. Third, internet users, armed with greater information about the house, neighbourhood, and prices of other recent sales, would pay less for the same housing/neighbourhood bundle. Recent movers in Wake County, North Carolina, were surveyed in early 2000, and the characteristics of web users were compared with nonusers. The major finding of this research is that to date, the internet has had little impact on search patterns, except that those using the internet tend to visit a larger number of houses personally than those who do not use the world wide web as an information source.
Analytical Modelling of Positional and Thematic Uncertainties in the Integration of Remote Sensing and Geographical Information Systems
Authors: Shi W.Z. , Ehlers M. , Tempfli K.
Published: March 2003

This paper describes three aspects of uncertainty in geographical information systems (GIS) and remote sensing. First, the positional uncertainty of an area object in a GIS is discussed as a function of positional uncertainties of line segments and boundary line features. Second, the thematic uncertainty of a classified remote sensing image is described using the probability vectors from a maximum likelihood classification. Third, the “S‐band” model is used to quantify uncertainties after combining GIS and remote sensing data.
Measuring Accessibility with GIS‐Tools: A Case Study of the Wild Coast of South Africa
Authors: Naude Andries , De Jong Tom , Van Teefelen Pieter
Published: March 2003

Although most GIS‐based planning support have the capacity to show the location and attributes of different places, very few GIS‐based systems are able to describe adequately the degree of spatial interaction, or the geographic accessibility, between places. The Faculty of Geographical Sciences of the Utrecht University (The Netherlands) and the South African Council for Scientific and Industrial Research (CSIR), are developing a methodology to address the problem of measuring accessibility by integrating specialised GIS software (FlowMap) that measures the geographic accessibility between locations within a spatial decision support system (AccessMap). The resulting GIS‐tool is applied to the Wild Coast area in South Africa. In this region a lack of accessibility to market centres is perceived as one of the major constraints of economic development in the region.
Apparent Fractal Dimensions from Continental Scale Digital Elevation Models Using Variogram Methods
Authors: McClean Colin J. , Evans Ian S.
Published: March 2003

It is often assumed that real land surfaces demonstrate the statistically self‐affine scaling behaviour of fractional Brownian surfaces. Tests of this assumption against empirical data, however, show many deviations. Estimates of fractal properties vary between methods and over different scale ranges. So far, this empirical evidence has come from the analysis of variograms for DEMs representing areas up to tens of kilometres in diameter. Here we report results obtained by using variograms to analyse land surface DEMs at the continental scale, with a grid resolution of 30 arc seconds. Results reveal variogram curvature and breaks of slope, but also linear sections over distance lags of hundreds of kilometres. The estimated mean fractal dimension calculated from these sections is 2.66, substantially higher for all continents at these broad scales (around 200 km) than values calculated at the erosional landscape scale (around 200 m). Thus the land surface is not self‐affine, and it is not clear that it follows any simple multifractal model. At the longest wavelengths, patterns found in the variograms appear to be related to broad tectonic features of the Earth's surface. For the reader to assess their quality and generality, estimates of fractal dimension should always be accompanied by statements of the scale range covered and the goodness of fit to a log‐linear relationship.
Multivariate Interpolation of Precipitation Using Regularized Spline with Tension
Authors: Hofierka Jaroslav , Parajka Juraj , Mitasova Helena , Mitas Lubos
Published: March 2003

Regularized Spline with Tension (RST) is an accurate, flexible and efficient method for multivariate interpolation of scattered data. This study evaluates its capabilities to interpolate daily and annual mean precipitation in regions with complex terrain. Tension, smoothing and anisotropy parameters are optimized using the cross‐validation technique. In addition, smoothing and rescaling of the third variable (elevation) is used to minimize the predictive error. The approach is applied to data sets from Switzerland and Slovakia and interpolation accuracy is compared to the results obtained by several other methods, expert‐drawn maps and measured runoff. The results demonstrate that RST performs as well or better than the methods tested in the literature. The incorporation of terrain improves the spatial model of precipitation in terms of its predictive error, spatial pattern and water balance.
An Evaluation of Four Different Wavelet Decomposition Procedures for Spatial Feature Discrimination in Urban Areas
Authors: Myint Soe Win , Lam Nina , Tyler John
Published: March 2003

Texture or spatial arrangement of neighborhood objects and features plays an important role in the human visual system for pattern recognition and image classification. The traditional spectral–based image processing techniques have proven inadequate for urban land use and land cover mapping from images acquired by the current generation of fine–resolution satellites. This is because of the high frequency spatial arrangements or complex nature of urban features. There is a need for an effective algorithm to digitally classify urban land use and land cover categories using high–resolution image data. Recent studies using wavelet transforms for texture analysis have generally reported better accuracy. Based on a high–resolution ATLAS image, this study illustrates four different wavelet decomposition procedures – the standard, horizontal, vertical, and diagonal decompositions – for urban land use and land cover feature extraction with the use of 33×33 pixel samples. The standard decomposition approach was found to be the most efficient approach in urban texture analysis and classification. For comparison purposes and to better evaluate the accuracy of wavelet approaches in image classification, spatial autocorrelation techniques (Moran’s I and Geary’s C) and the spatial co–occurrence matrix method were also examined. The results suggest that the wavelet transform approach is superior to all other approaches.
Overlay of Two Simple Polygons with Indeterminate Boundaries
Authors: Zhan F B , Lin H
Published: March 2003

This article outlines procedures that can be used to determine the boundaries and attributes associated with the resultant regions from the topological overlay of two simple polygons with indeterminate boundaries. After reviewing a definition of a simple polygon with indeterminate boundaries, this study first identifies the 10 resultant regions and 1,024 possible topological configurations from the overlay. Procedures for computing the boundaries of the 10 regions are discussed. Methods for determining the attributes associated with the 10 resultant regions are described. The effect of three typical overlay operations – intersection, difference, and union – on resultant regions is also discussed.
Morphological paradigms in language processing and language disorders
Authors: Clahsen Harald , Sonnenstuhl & Meike Hadler Ingrid , Eisenbeiss Sonja
Published: March 2003

We present results from two cross‐modal morphological priming experiments investigating regular person and number inflection on finite verbs in German. We found asymmetries in the priming patterns between different affixes that can be predicted from the structure of the paradigm. We also report data from language disorders which indicate that inflectional errors produced by language‐impaired adults and children tend to occur within a given paradigm dimension, rather than randomly across the paradigm. We conclude that morphological paradigms are used by the human language processor and can be systematically affected in language disorders.
Private Foreign Investment in India: Pain or Panacea?
Authors: Athreye Suma , Kapur Sandeep
Published: March 2003

Private foreign capital, whose presence in Indian industry was long regarded with concern and suspicion, is now presented as a panacea for India's poor industrial and export performance. This paper examines available evidence to compare the behaviour and performance of domestic and foreign‐controlled firms in India over the last five decades. It discusses the contribution of foreign capital to aggregate investment, balance of payments and economic growth. We assess the effects of government policy towards foreign investment, review recent changes, and outline implications for the future.
Does Trade Openness Promote Multilateral Environmental Cooperation?
Authors: Neumayer Eric
Published: March 2003

This article puts forward a number of arguments why trade openness might promote multilateral environmental cooperation. Most of these arguments are grounded in the substantive self‐interest of the trading country. It tests the proposition using a range of proxy variables for general trade openness as well as specific export interests. The article examines whether countries open to trade are more likely to have signed three recent multilateral environmental agreements (MEAs) and are more likely to have ratified early on another three agreements with quasi‐universal membership. After controlling for income, political freedom and population size, the empirical estimations find some weak evidence in favour of a possible synergy between trade openness and multilateral environmental cooperation. World Trade Organisation membership as well as general export openness go hand in hand with greater willingness to participate in multilateral environmental cooperation in some cases. However, whether specific trade interests promote or hinder multilateral environmental cooperation depends on whether the relevant agreement is likely to threaten or accommodate the interests of exporting countries.
International Outsourcing and the Skill–Specific Wage Bill in Eastern Europe
Authors: Egger Peter , Stehrer Robert
Published: March 2003

This paper analyses the effects of international fragmentation in terms of intermediate goods trade on the dynamics of the skilled–to–unskilled labour wage bill ratio in 14 manufacturing industries of the Czech Republic, Hungary and Poland. Both intermediate goods exports and imports of the CEEC exhibit a positive impact on the wage bill ratio. Since 1993, intermediate goods trade with the EU alone has accounted for a considerable reduction of the predicted annual change in the skilled–to–unskilled wage bill ratio in the three CEEC.
Re‐examining Caribbean English Creole Continua
Authors: Winford Donald
Published: March 2003

This paper re‐examines the history and contemporary structure of Caribbean English creole continua, with illustration from the varied sociolinguistic situations in Belize, Guyana, Jamaica and Trinidad. It argues for the view that continua existed in these situations from the earliest period of contact, and challenges the claim that they evolve solely via ‘decreolization’ of basilects under influence from acrolects. It also argues for a co‐existent systems approach to the contemporary structure of these continua. The evidence of sociolinguistic studies supports the idea that they result from interaction between relatively stable grammars, conditioned by social and situational factors. The variation produced by this interaction provides insight into the kinds of shift and contact‐induced change that have always operated in these situations.
Regional Variations in the Phonological Characteristics of African American Vernacular English
Authors: Hinton Linette N. , Pollock Karen E.
Published: March 2003

At present little is known about regional variations in the phonological characteristics of African American Vernacular English (AAVE). Regional variation in AAVE allows for a closer examination of the convergence‐divergence controversy. Researchers are still in disagreement on whether AAVE is converging to white speech or diverging away from white vernaculars. In addition, speakers of AAVE who have more contact with whites have been observed to assimilate toward such speech and have less of a change in their lexicons and phonologies (Ash and Myhill, 1986). These findings have implications for the dialects of African Americans residing in the midwest region where communities are less segregated.

The present study investigated AAVE dialect features in the midwestern community of Davenport, Iowa and compared them to those reported by Pollock and Berni (1997) for Memphis, Tennessee – specifically, productions of vocalic and postvocalic /r/ across African American speakers from Davenport and Memphis.

Results showed that AAVE speakers from Davenport produced vocalic and postvocalic /r/ in all contexts, in sharp contrast to AAVE speakers from Memphis who showed a consistent pattern of variation in /r/ usage according to phonetic context. The implications of the findings are discussed and directions for future research are outlined.
TOEFL to the Test: are Monodialectal AAL‐speakers Similar to ESL Students?
Authors: Pandey Anita
Published: March 2003

In this paper, I draw attention to the validity of the Oakland School Board's resolution on Ebonics, and to the value of ESL‐based approaches to the teaching of ‘Standard American English’ to speakers of other dialects of American English. I do so by demonstrating the validity of comparisons made between monodialectal speakers of African‐American Language (AAL)/‘Ebonics’ and low‐level ESL students, and by illustrating the bidialectalism‐instilling potential of the Test of English as a Foreign Language (TOEFL). Use of this proficiency test puts the spotlight on a much‐neglected area, namely, the bidialectal or dialect‐specific nature of listening comprehension for pre‐college and first‐year students raised in the inner city. The findings of two longitudinal studies are cited to demonstrate that, for many Ebonics‐speakers, SAE is much like a second language. The students' performance on the TOEFL, particularly on the listening comprehension and grammar sections, suggests that both comprehension and production of ‘Standard English’ can be problematic for transitional students whose first language is AAL. The pedagogical implications of this finding are carefully explored.

Every time I say something the way I say it, she correct me until I say it some other way. Pretty soon it feel like I can't think. My mind run up on a thought, git confuse, run back and sort of lay down.….

Look like to me only a fool would want you to talk in a way that feel peculiar to your mind.

(Alice Walker, 1982: 183–4)
Relative clauses in Hong Kong English
Authors: Gisborne Nikolas
Published: March 2003

This paper discusses relative clauses in Hong Kong English, and considers a number of questions about the morphosyntactic feature system of Hong Kong English, comparing relevant attestations from local data to those found in other varieties of English. It looks at the ways in which relative constructions in Cantonese may affect how relative clauses in Hong Kong English are formed, and also examines the degree to which the relative clause system of Hong Kong English is independent of the relative clause system of both Cantonese and standard native‐speaker varieties of English, and therefore could be said to provide evidence of whether Hong Kong English is an independent variety of English or not.
Teaching world Englishes to native speakers of English in the USA
Authors: Kubota Ryuko
Published: March 2003

The global spread of English has increased opportunities for native English speakers in the US to interact with other speakers of world Englishes (WE). However, these native speakers are rarely encouraged to develop the knowledge and skills necessary for intercultural communication, often resulting in a one‐way communicative burden imposed on the WE speakers. To explore ways to redress this problem, a pilot project was conducted in an English IV class at a public high school. The purposes were to raise students' awareness of the global spread of English and its implications and to have them explore ways to communicate effectively with WE speakers. This paper describes the instructional unit developed for the project and its effect on students' views on various issues related to communicating with WE speakers, and on their perceptions and comprehension of WE speech samples. The instructional effect was investigated by pre‐ and post‐questionnaires and dictation tests, classroom observations, and post‐study interviews. A total of 17 students participated. Results of t‐tests for the questionnaires and dictation showed no significant effect except on beliefs about second language acquisition and perceived comprehension of the speech samples. Classroom observations and interviews revealed individual differences in the instructional effect. The paper offers implications and future directions.
English in education in China: policy changes and learners’ experiences
Authors: Lam Agnes
Published: March 2003

Since the establishment of the People’s Republic, China has undergone various changes in language policy, both in the standardization of indigenous languages and foreign–language enhancement. This paper focuses on the growing importance of English, in terms of policy emphasis and in learners’ experience. A historical account of six phases of foreign–language education policy is first provided. In the light of such changes, it is to be expected that learners’ experience would vary over time. The second part of the paper presents some survey statistics on the experience of different cohorts of learners from two backgrounds: 214 non–foreign–language specialists and 193 foreign–language specialists. To complement the statistical discussion, excerpts from transcripts of four interviews are provided. The survey and interview data taken together indicate that as policy efforts to promote English in education escalate, younger cohorts of learners have experienced more favourable learning circumstances.
Empire and Democracy: Tocqueville and the Algeria Question
Authors: Pitts Jennifer
Published: March 2003

In the closing years of the eighteenth century, a great intellectual and moral challenge to European empire was launched by many of the most innovative thinkers of the day, including Kant, Adam Smith, Bentham, Burke, Diderot, and Condorcet. They drew on a strikingly wide range of ideas to argue against empire: among others, the rights of man and the imperative of popular self‐determination, the economic wisdom of free trade and foolishness of conquest, the corruption of natural man by a degenerate civilization, the hypocrisy required for self‐governing republics to rule despotically over powerless subjects, and the impossibility of sustaining freedom at home while practicing despotism abroad.
Tax–Benefit Linkages in Pension Systems: A Note
Authors: Bütler Monika
Published: March 2003

This note shows that a public pension system with a fairly general individual tax–benefit linkage is (computationally) equivalent to a system without linkages. The “equivalent” pension system without linkages not only facilitates simulations of policy experiments but also offers some insight into the implied tax structure of the tax–benefit linkage. It is shown that implicit tax rates may differ considerably across age groups even if the statutory tax rate is constant over the life‐cycle.
Phonological sensitivity and reading: evidence from precocious readers
Authors: Stainthorp Rhona , Hughes Diana
Published: March 2003

This paper reports the results from a study investigating the level of phonological sensitivity, letter knowledge and reading ability of two groups of children between the ages of 5 and 7 years. One group of children were identified as being fluent readers at the age of 5 years, before they had begun school. These children were paired with a group of children of the same age and vocabulary development but who were not yet reading. The performance of the two groups of children on the tasks measuring phonological sensitivity confirmed the view of Stanovich (1986, 1992) that phonological sensitivity lies on a continuum from shallow to deep. Shallow levels of phonological sensitivity, tapped by rhyming tasks, seem to be necessary for reading to progress whereas deeper levels of sensitivity develop later and have a more reciprocal relationship to reading progress.
Computerised baseline assessment of literacy
Authors: Singleton Chris , Horne Joanna , Thomas Kevin
Published: March 2003

In a study using the literacy module from CoPS Baseline, a computerised assessment system, 153 children were assessed at an average age of 4 years 10 months, and progress in reading was followed up 12 months later. The results indicated that the computerised baseline assessment module produced a satisfactory distribution of scores across the intended age range, and the shorter adaptive form of the baseline test correlated highly (r = 0.81) with the full form. Baseline scores gave a good overall prediction of reading development over the first year of schooling (r = 0.74), regardless of the child’s age. Correlations between the 8 skill/concept areas that comprise the baseline assessment and reading ability 12 months later were consistent with other findings reported in the literature. It was concluded that the objectivity that characterises computerised assessment could provide a more consistent and dependable approach to baseline assessment.
Baseline assessment in Scotland
Authors: MacKay Tommy
Published: March 2003

Baseline assessment in Scotland has developed in a different context from the rest of the UK. Early in 1998, the Scottish Office Education and Industry Department launched a national framework which is now being piloted in a number of education authorities across the country. Meanwhile, authorities had developed schemes of baseline assessment to evaluate their programmes of early intervention in literacy. This study presents a survey of these schemes in all 32 Scottish education authorities, together with a description of the national scheme and a discussion of the main issues arising. Within the context of baseline assessment across the curriculum it provides a profile of an important but very diverse national literacy initiative.
Predicting word‐spelling difficulty in 7‐ to 11‐year‐olds
Authors: Spencer Ken
Published: March 2003

Some languages have simple grapheme‐phoneme codes in which there is a one‐to‐one mapping, making them easy to teach and learn, while others have more complicated structures and are more difficult for teachers and students. There is now an increasing number of studies which demonstrate that readers in more transparent orthographies such as Italian, Spanish, Turkish, Greek and German have little difficulty in decoding written words, while English children have many more problems. Increasingly, lack of orthographic transparency in English is seen as having a powerful negative effect on the development of literacy skills in English‐speaking children.

In the present study, the word factors associated with poor spelling in 5 school year‐groups (ages 7 to 11 years) are identified as: (a) frequency of the word in the English language, (b) length of the word and (c) a measure of the phoneticity of the word. The concept of word phoneticity is explored and data is presented illustrating the predictive model of spelling. The implications the model has for teaching and learning English are discussed, with particular reference to the beneficial effects that greater orthographic transparency would have for children.
Teenagers in cyberspace: an investigation of language use and language change in internet chatrooms
Authors: Merchant Guy
Published: March 2003

This article reports on a small‐scale investigation into the use of Internet chatrooms by teenage girls. Based on interview and observational data, it illustrates how the use of popular electronic communication is resulting in linguistic innovation within new, virtual social networks in a way that reflects more wide‐reaching changes in the communication landscape. The paper suggests that teenagers and young people are in the vanguard of these processes of change as they fluently exploit the possibilities of digital technology, radically changing the face of literacy. The study looks at teenagers’ perceptions of chatroom encounters and their learning about new ways of social and linguistic interaction. Observations of teenagers online show how rapid written conversations which combine features of face‐to‐face talk with explorations in interactive writing and the exchange of additional digital information, such as image files and web addresses, are enabling these young people to develop sophisticated and marketable skills. These innovations are contrasted with recent media and educational criticism of the language use associated with new technology. This tension between change and conservatism is explored by applying Bourdieu’s concept of ‘linguistic capital’.
Phonological awareness and musical aptitude
Authors: Peynirciogˇlu Zehra F. , Durgunogˇlu Aydyn Y. , Úney‐Küsefogˇlu Banu
Published: March 2003

The relationship between phonological awareness and musical aptitude in pre‐school children was examined. In Experiment 1, Turkish children, and in Experiment 2, American children performed various phoneme deletion tasks with words in their respective native languages and with pseudo‐words. They also did initial and final tone deletion tasks with snippets of melodies. Because none of these children knew how to read, both tasks were presumed to depend largely on pure auditory skills. In general, success in the different phoneme deletion tasks reflected the characteristics of the specific languages with which the children were familiar. In addition, in both experiments, children in the high musical aptitude group did much better on all tasks than those in the low musical aptitude group, showing that success in manipulating linguistic sounds was related to awareness of distinct musical sounds.
Developing audience awareness in writing
Authors: Carvalho José Brandâo
Published: March 2003

Beginning writers need to consider their audience; but this is only possible when the writer has reached a certain stage of cognitive development, as it is necessary to consider an absent reality (e.g. an audience reading the piece at a later point). Adapting the text to the audience is only possible when the physical task of writing becomes automatic and the writer is no longer absorbed by it. Then the writer is free to pay attention to other aspects of the task without overloading cognitive processes. Procedural facilitation involves the use of external aids to support a simplified version of the processes used by expert writers. It may function as a way of enabling beginning writers to adapt what they write for their audiences. At the same time, as this task becomes automatic, it may be seen as a way of promoting writing development. A quasi–experimental study is described in which a procedural facilitation strategy is used to promote writing skills, in particular, the skill of suiting the text to the communicative context. The study was with fifth and ninth grade Portuguese students. The results of the post–test show significant progress for the experimental groups in contrast to the control groups.
Estimation of Quantities of Drugs Handled and the Burden of Proof
Authors: Aitken C. G. G. , Bring J. , Leonard T. , Papasouliotis O.
Published: March 2003

A person is convicted for the handling of drugs. In the USA, the sentence must be determined partly on the total quantity of drugs handled. The determination of this quantity is a controversial estimation problem. Moreover, there is confusion concerning the relationship of this problem and the burden of proof. Various aspects of this problem are discussed in the context of three cases, each of which requires a different approach. In the first, a product of two uniform distributions is determined. In the second, there is simulation based on resampling from a training set. In the third, a predictive distribution based on independent priors for the mean and variance of a normal distribution is derived.
Statistical Issues in Phase III Human Immunodeficiency Virus Vaccine Trial Design
Authors: Halloran M. E.
Published: March 2003

Several scientific questions are of interest in phase III trials of prophylactic human immunodeficiency virus (HIV) vaccines. In this paper we focus on some issues related to evaluating the direct protective effects of a vaccine in reducing susceptibility, VES, and its effect on reducing infectiousness, VEI. An estimation of VEI generally requires information on contacts between the infective and susceptible individuals. By augmenting the primary participants of an HIV vaccine trial by their steady sexual partners, information can be collected that allows an estimation of VEI as well as VES. Exposure to infection information, however, may be expensive and difficult to collect. A vaccine trial design can include a small validation set with good exposure to infection data to correct bias in a larger, simpler main study with only coarse exposure data. The large main study increases the efficiency of the small validation set. More research into the combination of different levels of information in vaccine trial design will yield more efficient and less biased estimates of the efficacy measures of interest.
Sustainability Indicators—Integrating Quality of Life and Environmental Protection
Authors: Levett R.
Published: March 2003

The struggle to find and use indicators of sustainable development is intimately bound up with the process of deciding what we mean by sustainable development and what we shall do about it. In this field at least, indicators are intrinsically and unavoidably normative and political. The paper proposes an approach to indicators which reflects, and can further clarify and help to achieve, an important aspect of sustainable development. The paper is written from a practical, instrumental interest in indicators as a tool to put sustainable development principles into practice in public policy. The author is not a statistician and makes no claim to technical expertise but hopes that this ‘barefoot’ practitioner perspective may be of some interest to the professionals. The main argument is introduced by a discussion of some of the pitfalls and limitations of sustainability indicators to date.
A Multilevel Exploration of the Role of Interviewers in Survey Non-Response
Authors: O’Muircheartaigh Colm , Campanelli P.
Published: March 2003

This paper illustrates the use of multilevel statistical modelling of cross-classified data to explore interviewers’ influence on survey non-response. The results suggest that the variability in whole household refusal and non-contact rates is due more to the influence of interviewers than to the influence of areas. The results from separate logistic regression models are compared with the results from multinomial models using a polytomous dependent variable (refusals, non-contacts and responses). Using the cross-classified multilevel approach allows us to estimate correlations between refusals and non-contacts, suggesting that interviewers who are good at reducing whole household refusals are also good at reducing whole household non-contacts.
A Design for Testing Clinical Strategies: Biased Adaptive Within-Subject Randomization
Authors: Lavori Phillip W. , Dawson R.
Published: March 2003

We propose a method for assigning treatment in clinical trials, called the ‘biased coin adaptive within-subject’ (BCAWS) design: during the course of follow-up, the subject’s response to a treatment is used to influence the future treatment, through a ‘biased coin’ algorithm. This design results in treatment patterns that are closer to actual clinical practice and may be more acceptable to patients with chronic disease than the usual fixed trial regimens, which often suffer from drop-out and non-adherence. In this work, we show how to use the BCAWS design to compare treatment strategies, and we provide a simple example to illustrate the method.
Number Needed to Treat: Properties and Problems
Authors: Hutton J. L.
Published: March 2003

The inverse of a difference in probabilities, called the ‘number needed to treat’, has been promoted in the medical literature as a good way to present the results of modelling binary outcomes. The usual context is randomized controlled trials and meta-analyses. In this paper we discuss the claims that have been made about this statistic, and the problems associated with it. Methods which have been proposed for confidence intervals are evaluated and shown to be erroneous. We suggest that the difference in probabilities, the ‘absolute risk reduction’, is preferable to the number needed to treat, for both theoretical and practical reasons.
The Value of the Aggregate Data Approach in Meta-Analysis with Time-to-Event Outcomes
Authors: Tudur Catrin , Williamson Paula R. , Khan Saboor , Best Lesley Y.
Published: March 2003

Collecting individual patient data has been described as the ‘gold standard’ for undertaking meta-analysis. If studies involve time-to-event outcomes, conducting a meta-analysis based on aggregate data can be problematical. Two meta-analyses of randomized controlled trials with time-to-event outcomes are used to illustrate the practicality and value of several proposed methods to obtain summary statistic estimates. In the first example the results suggest that further effort should be made to find unpublished trials. In the second example the use of aggregate data for trials where no individual patient data have been supplied allows the totality of evidence to be assessed and indicates previously unrecognized heterogeneity.
Predicting Successful and Unsuccessful Transitions from School to Work by Using Sequence Methods
Authors: McVicar Duncan , Anyadike-Danes Michael
Published: March 2003

Policy makers recognize the importance of identifying early young people who are likely to end up jobless on entry to the adult labour market. This paper uses sequence techniques to characterize 712 young peoples’ transitions from school to work into ‘types’, with jobless types interpreted as unsuccessful transitions. A logit model is estimated for transition type using a collection of static individual, family and school characteristics. This allows us to identify which young people are most likely to experience unsuccessful transitions into the adult labour market. Policy makers might use such information to target social and educational policy more effectively to promote social inclusion.
Effects of Neighbourhood Demographic Shifts on Findings of Environmental Injustice: A New York City Case-Study
Authors: Talih Makram , Fricker Ronald D.
Published: March 2003

We study the question of how changes in neighbourhood demographics affect findings of environmental equity. Many cross-sectional studies of association between neighbourhood racial and ethnic composition and the location of environmentally undesirable sites have been conducted. However, no evaluations have been conducted that examine how neighbourhood demographics change over time, and how those changes are related to the observed cross-sectional results. If the question is whether an observed association is the result of discrimination, it is crucial that the historical changes in neighbourhood structure are well understood. We develop some methods based on standard statistical techniques and illustrate their application by using the metropolitan New York City region as a case-study.
Likelihood Ratio Tests for Fixed Model Terms using Residual Maximum Likelihood
Authors: Welham S. J. , Thompson R.
Published: March 2003

Likelihood ratio tests for fixed model terms are proposed for the analysis of linear mixed models when using residual maximum likelihood estimation. Bartlett-type adjustments, using an approximate decomposition of the data, are developed for the test statistics. A simulation study is used to compare properties of the test statistics proposed, with or without adjustment, with a Wald test. A proposed test statistic constructed by dropping fixed terms from the full fixed model is shown to give a better approximation to the asymptotic χ2-distribution than the Wald test for small data sets. Bartlett adjustment is shown to improve the χ2-approximation for the proposed tests substantially.
Hierarchical Generalized Linear Models and Frailty Models with Bayesian Nonparametric Mixing
Authors: Walker Stephen G. , Mallick Bani K.
Published: March 2003

This paper proposes Bayesian nonparametric mixing for some well-known and popular models. The distribution of the observations is assumed to contain an unknown mixed effects term which includes a fixed effects term, a function of the observed covariates, and an additive or multiplicative random effects term. Typically these random effects are assumed to be independent of the observed covariates and independent and identically distributed from a distribution from some known parametric family. This assumption may be suspect if either there is interaction between observed covariates and unobserved covariates or the fixed effects predictor of observed covariates is misspecified. Another cause for concern might be simply that the covariates affect more than just the location of the mixed effects distribution. As a consequence the distribution of the random effects could be highly irregular in modality and skewness leaving parametric families unable to model the distribution adequately. This paper therefore proposes a Bayesian nonparametric prior for the random effects to capture possible deviances in modality and skewness and to explore the observed covariates’ effect on the distribution of the mixed effects.
A Semiparametric Method of Multiple Imputation
Authors: Lipsitz Stuart R. , Zhao Lue Ping , Molenberghs Geert
Published: March 2003

In this paper, we describe how to use multiple imputation semiparametrically to obtain estimates of parameters and their standard errors when some individuals have missing data. The methods given require the investigator to know or be able to estimate the process generating the missing data but requires no full distributional form for the data. The method is especially useful for non-standard problems, such as estimating the median when data are missing.
Polynomial Regression With Errors in the Variables
Authors: Cheng Chi-Lung , Schneeweiss Hans
Published: March 2003

A polynomial functional relationship with errors in both variables can be consistently estimated by constructing an ordinary least squares estimator for the regression coefficients, assuming hypothetically the latent true regressor variable to be known, and then adjusting for the errors. If normality of the error variables can be assumed, the estimator can be simplified considerably. Only the variance of the errors in the regressor variable and its covariance with the errors of the response variable need to be known. If the variance of the errors in the dependent variable is also known, another estimator can be constructed.
Bivariate Quantile Smoothing Splines
Authors: He Xuming , Ng P. , Portnoy S.
Published: March 2003

It has long been recognized that the mean provides an inadequate summary whereas the set of quantiles can supply a more complete description of a sample. We introduce bivariate quantile smoothing splines, which belong to the space of bilinear tensor product splines, as nonparametric estimators for the conditional quantile functions in a two-dimensional design space. The estimators can be computed by using standard linear programming techniques and can further be used as building-blocks for conditional quantile estimations in higher dimensions. For moderately large data sets, we recommend penalized bivariate B-splines as approximate solutions. We use real and simulated data to illustrate the methodology proposed.
Calibrating the Excess Mass and Dip Tests of Modality
Authors: Cheng Ming-Yen , Hall Peter
Published: March 2003

Nonparametric tests of modality are a distribution-free way of assessing evidence about inhomogeneity in a population, provided that the potential sub populations are sufficiently well separated. They include the excess mass and dip tests, which are equivalent in univariate settings and are alternatives to the bandwidth test. Only very conservative forms of the excess mass and dip tests are available at presently, however, and for that reason they are generally not competitive with the bandwidth test. In the present paper we develop a practical approach to calibrating the excess mass and dip tests to improve their level accuracy and power substantially. Our method exploits the fact that the limiting distribution of the excess mass statistic under the null hypothesis depends on unknowns only through a constant, which may be estimated. Our calibrated test exploits this fact and is shown to have greater power and level accuracy than the bandwidth test has. The latter tends to be quite conservative, even in an asymptotic sense. Moreover, the calibrated test avoids difficulties that the bandwidth test has with spurious modes in the tails, which often must be discounted through subjective intervention of the experimenter.