bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring Gentrification and Displacement in Greater London
Authors: Atkinson Rowland
Published: July 2002

The use of aggregate data to understand the linkages between gentrification and displacement has been considered problematic because of a lack of refinement or closeness to the nature of these processes as well as lacking the ability to 'track' displacees. This paper presents the results of pioneering work designed to overcome these problems by combining cross-sectional census data with spatially re-aggregated longitudinal census data (the Longitudinal Study). Using established approaches to measure gentrification, via proxy measures, and devising others for its potential displacees, the work demonstrates a displacement effect clustered around gentrified wards. Attempts are made to quantify flows of displacement relative to city-wide changes over the decade. The paper concludes that, although replacement and displacement are difficult to distinguish, displacement appears prevalent for certain groups and this requires further research initiatives to explore a process that is socially and psychologically harmful.
Globalisation, Regions and the State: Exploring the Limitations of Economic Modernisation through Inward Investment
Authors: Phelps Nicholas A. , Tewdwr-Jones Mark
Published: July 2002

Over the past 10 years or so, the UK has witnessed intense interregional competition for a small number of large inward investment projects. These projects, examples of foreign direct investment (FDI) from Far East Asia, have been relied upon by nation-states as panaceas to the economic problems being experienced within older industrial regions. Central government has adopted a non-interventionist approach to FDI and has rather encouraged regional-level institutions of governance to provide innovative and competitive packages of aid to the prospective investors through the creation of customised spaces. By relying on this FDI, local and regional-level institutions within the UK have sought to reduce or eliminate those uncertainties associated with local governance and the planning system that would otherwise face potential investors. We discuss these issues with reference to three case-study FDI examples: LG in South Wales, Samsung in the North East of England and Hyundai in Scotland. These projects provide good examples of the prestige attached to large FDI projects by regional and local agencies: by-passing normal local democratic processes; instigating streamlined institutional processes; and ignoring environmental protection policies to `land' the projects for particular regions. But the collapse of the south-east Asian economies and the recent mothballing of both the Hyundai and LG plants illustrate some very immediate problems regarding the unsustainability of the nation-state both relying on the global market and subordinating local interstices to resolve regional economic problems. Overall, the paper examines how particular state forms and practices operate to privilege certain types of interests and activities at certain scales, and how particular state entities are attempting to capture agendas and decisions at particular scales of governance.
The Public Sector and Core-Periphery Models
Authors: Lanaspa Luis Fernando , Pueyo Fernando , Sanz Fernando
Published: July 2002

In this paper, we present an extension to Krugman's core-periphery model-namely, the introduction of the public sector as a new economic agent. There are two main results: first, we demonstrate theoretically that regions with a lower tax-burden in net terms, in the sense of having lower taxes and/or higher levels of public efficiency in their management, offer greater incentives to attract economic activity; secondly, the influence of the transport costs on the equilibria is not monotonous, as under the original approach, but now depends on its size, reflecting a strong interdependence between all the parameters of the model.
'It's Not Community Round Here, It's Neighbourhood' : Neighbourhood Change and Cohesion in Urban Regeneration Policies
Authors: Meegan Richard , Mitchell Alison
Published: July 2002

Neighbourhood has become a key spatial scale in the UK government's policies for urban regeneration and social inclusion, resuscitating the long-standing debate over the efficacy of area-based policies. The paper argues that the latter need to be sensitive to the interaction between macro-structural and local, reinforcing processes and that 'people-based' policies need to be complemented by 'people and place' ones. The complexities of `neighbourhood' definition are explored, using the distinction between `neighbourhood' and 'place-based community' to support an argument for seeing neighbourhoods as an appropriate spatial scale for understanding the operation of 'everyday life-worlds'. Drawing on research based on a specific regeneration initiative, the 'Pathways to Integration' priority of the Objective 1 Structural Funds Programme for Merseyside (1994-99), the paper goes on to explore the political and operational issues surrounding the spatial targeting of policy and some of the partnership issues surrounding `neighbourhood' and 'community'. It argues that area-based policies and spatial targeting are inherently political as well as technical exercises that need to be sensitive to the social-spatial construction of neighbourhoods and that the operational definition of policy areas should be part of an evolutionary process of community engagement.
Agglomeration and Dispersion of High-order Service Employment in the Montreal Metropolitan Region, 1981-96
Authors: Coffey William J. , Shearmur Richard G.
Published: July 2002

Much of the recent urban literature on suburban employment centres has neglected the role of high-order services, perhaps the principal component of 'edge cities', in the creation of the evolving multinucleated metropolitan structure. This paper specifically explores the role of high-order services in this process. We use employment by place-of-work data at the census-tract level to examine the changing intrametropolitan geography of employment in four finance, insurance and real estate (FIRE) services and eight business services in the Montreal area over the period 1981-96. We find evidence of central business district (CBD) decline in relative, but not absolute, terms. The resulting decentralisation has clearly assumed the form of polycentricity rather than of generalised dispersion. In spite of recent advances in telecommunications technologies, agglomeration economies continue to exert an important impact upon intrametropolitan location.
The Evaluation of Community Economic Development Initiatives
Authors: Armstrong H.W. , Kehrer B. , Wells P. , Wood A.M.
Published: July 2002

Community economic development (CED) initiatives expanded rapidly in urban and regional policy in the 1990s. Traditional evaluation methodology has, however, proved to be extremely difficult to apply effectively to CED. This paper examines existing monitoring and evaluation procedures for CED, the problems faced in applying traditional methodology and possible ways forward to ensure that more effective monitoring and evaluation can be undertaken. Evidence is drawn from four detailed case studies of urban CED projects funded as part of the 1994-96 Yorkshire and the Humber Objective 2 Structural Funds programme. These case studies were deliberately designed to experiment with alternative quantitative and qualitative evaluation methods.
Modelling Tenants' Choices in the Public Rented Sector: A Stated Preference Approach
Authors: Walker Bruce , Marsh Alex , Wardman Mark , Niner Pat
Published: July 2002

This paper uses a stated preference (SP) approach to examine the potential housing choices of tenants in the UK public housing sector. The paper begins by explaining the policy significance of the choices that such tenants might make if alternative dwellings were offered to them. It then discusses the SP approach in general before explaining the way in which it is used in this study. The results of the SP modelling exercise are presented. These suggest that tenants are unlikely to move to housing estates that they see as being worse than their current estate solely in response to lower rents. This is because a number of factors other than rent are of more significance in their potential housing decisions.
A Methodology for the Disaggregate, Multidimensional Measurement of Residential Neighbourhood Type
Authors: Bagley Michael N. , Mokhtarian Patricia L. , Kitamura Ryuichi
Published: July 2002

Binary designation of a residential neighbourhood as either traditional or suburban is a distortion of reality, since a location may have some characteristics of both types and since residents in different parts of the neighbourhood may perceive its character differently. This paper presents and applies a methodology for assessing neighbourhood type that results in a measure that is continuous rather than binary, disaggregate rather than aggregate, and potentially multidimensional. Specifically, 18 variables identified by the literature as distinguishing traditional and suburban locations are measured for 852 residents of 5 San Francisco area neighbourhoods. These data are factor-analysed to develop scales on which each individual has a person-specific score. Although we expected a single 'traditionalness' dimension to result, instead we found two factors: traditional and suburban. Study neighbourhoods could and did score highly on both dimensions, and considerable individual variation within neighbourhood was observed. By more accurately capturing the complexity in classifying a neighbourhood and the heterogeneity of individual perception within a neighbourhood, use of this methodology to measure neighbourhood type is expected to improve models involving residential location as an endogenous or exogenous variable.
The Architect's Perspective
Authors: Callado Jose
Published: July 2002

This paper examines the issue of quality in housing design through reference to the manner in which the living space is utilised. Treating spatial structures as territories of interaction, a new set of parameters—defined as hierarchies of area and order—are used to assess the impact of functionalist housing design upon the usage of living space and hence quality. A series of case studies undertaken in Lisbon are employed to highlight the observation that the fixed model of human behaviour implied in functionalist design fails to support a flexible usage of the dwelling space. The paper concludes that there is a consequent need to develop spatially oriented models of housing design.
The Real Estate Economy and the Design of Russian Housing Reforms, Part II
Authors: Renaud Bertrand
Published: July 2002

The transition from plan to market in socialist economies dominates the economic agenda of this decade. This two-part paper on the Russian housing reforms addresses four questions. First, what is the legacy of the administrative-command system and why were demands for major reforms so widespread in the housing sector? Secondly, in what manner does the severe contraction of the Russian economy complicate the reformers' task? Thirdly, how has the Russian government responded so far to the reform challenge? Fourthly, why are the privatisation of housing and rent reforms at the core of the transition to market? The first part of the paper deals with the first two questions. The second part addresses the last two questions. Priority goes to an integrated perspective on the early stages of Russian reforms over an in-depth analysis of individual issues. The modern analysis of the real estate economy distinguishes two markets: the 'property market' for the allocation of space, and the 'asset market' where investment decisions are made. This theoretical insight provides a much needed framework to understand how the key components of Russian reform interact during the housing transition to market.
Localities for Epidemiological Monitoring and Health Policy
Authors: Congdon Peter
Published: July 2002

The impetus behind locality arrangements in Health Districts in the UK is discussed in terms of recent reform of the structure of health services, and in particular the greater stress on primary and community provision, and on health prevention and promotion. Implications for needs assessment and resource allocation are considered. The advantages of using localities for epidemiological monitoring and for assessing inequality are illustrated with a case study of two outer East London boroughs; the reduction of inequity is discussed with reference to the achievement of overall health gain targets.
A Hedonic Analysis of Rent and Rental Revenue in the Subsidised and Unsubsidised Housing Sectors in Geneva
Authors: Buchel Sandra , Hoesli Martin
Published: July 2002

In this paper, an analysis is made of what would be the rent difference for the tenants of subsidised units if these units were rented as unsubsidised units. Furthermore, the existence of any pecuniary disadvantage for the owner of a subsidised unit is investigated by considering his rental revenue (i.e. the amount paid by the tenant and the subsidy). It is found that there exists a premium between an unsubsidised and a subsidised unit when using the amount paid by the tenant (i.e. the rent) as the dependent variable. Also, the subsidy system in Geneva has an influence on the pricing of each characteristic of a unit. Furthermore, it is found that when using rental revenue as the dependent variable, both sub-samples can be used in a single hedonic equation. Thus, owners of subsidised units are not at a disadvantage due to the granting of a subsidy. As a result, Geneva's subsidy system matches the goals of agents on both the demand and supply sides.
Race and Tenure in Toronto
Authors: Skaburskis Andrejs
Published: July 2002

The analysis of a number of Toronto sub-populations consistently points to differences in the home-ownership rates between visible minorities and whites. People of African or Caribbean origin have a much lower chance of being home-owners compared to whites after controlling for differences in income levels, housing preferences and household characteristics. Differences in tenure profiles are reduced at higher income levels but the home-ownership deficit remains. Economic factors explain only a small part of the large difference. Cultural and institutional factors may determine how the tenure options are perceived and valued by different groups of people living in the same city. Biases in perceptions matter as they affect the extent to which people can gain from the direct and indirect subsidies offered to home-owners. The differences may be indicative of underlying problems some minorities face in gaining access to urban resources. Measures of home-ownership deficits among the black and Caribbean suggest the need for social policy that goes beyond income maintenance and housing subsidies groups to help equalise their social and economic opportunities.
Housing and the Scottish New Towns: A Case Study of Policy Termination and Quasi-markets
Authors: Goodlad Robina , Scott Suzie
Published: July 2002

This paper examines the wind-up of the British new towns programme in Scotland, and the way in which housing tenure became a critical issue. The origins and development of the new towns are outlined, and the parts played by the main actors in the wind-up are considered. The paper is based on primary and secondary sources, and on interviews. The outcome-the transfer of a large proportion of the rented housing to local authorities—was not government policy, and this is explained by reference to models of policy termination and succession, and to developments in the creation of 'quasi-markets', which created expectations of consumer choice.
Speculation in the Housing Market?
Authors: Levin Eric J. , Wright Robert E.
Published: July 2002

This paper presents and tests a model of house price speculation. The mechanisms by which price speculation may occur in the housing market are described and formalised. A model of house prices is constructed that allows for speculation. Aspects of this model are tested using time-series data for the UK and the Greater London area (1969-95). Overall, the analysis presents some evidence of the process of speculation as a possible determinant of house prices in the London and UK-wide housing markets.
The Choice of Functional Form and Variables in the Hedonic Price Model in Seoul
Authors: Huh Serim , Kwak Seung-Jun
Published: July 2002

This study demonstrates that the important part of exploring the proper functional form of the hedonic price model would include investigating a dissimilar and unique hedonic price structure when the hedonic price model is applied to different housing markets. Based on the adjustment to the usual technique necessitated by the regional and cultural setting of Seoul, the criteria for significance of implicit price, root-mean-square-percentage-error, and the log-likelihood ratio test are applied to the choice of a useful functional form. We conclude that investigating the structure of a local housing market and choosing proper variables reflecting regional and cultural characteristics, both key parts of such a study, require significant adjustment to the reality of Seoul.
Accounting for the Change in Income Disparities between US Central Cities and their Suburbs from 1980 to 1990
Authors: Hill Edward W. , Wolman Harold L.
Published: July 2002

In this paper we are concerned with the widely acknowledged policy problem of substantially higher levels of per capita income in suburban areas of US metropolitan areas compared to that of their central cities. We focus on causes of changes in this per capita income gap from 1980 to 1990 (for those metropolitan areas where such a gap existed in 1980) in an effort to determine what factors are associated with narrowing of these disparities. We do so by first describing the relationship between central-city and suburban per capita income across American metropolitan areas in 1980 and 1990. We review the connection between the operation of metropolitan labour markets and changes in suburban-central-city income disparities. We then develop regression models of changes in income disparities for all 111 metropolitan statistical areas (MSAs) with populations of at least 250 000 in 1980 and where suburban per capita income exceeded central-city per capita income in 1980. This is followed by a summary of the results.
Mortgage Lending and Residential Integration in a Hypersegregated MSA: The Case of St Louis
Authors: MacDonald Heather I.
Published: July 2002

Have mortgage lending reforms during the first half of the 1990s been associated with improvements in the home-ownership prospects of black residents? Have the spatial patterns of loan applications changed, to increase lending activity in lower-income tracts and to advance residential integration? This paper investigates changes in mortgage lending activity in the St Louis metropolitan area over the period 1990-94. Analysis of Home Mortgage Disclosure Act (HMDA) data suggests that the home-ownership prospects of black St Louis residents improved over that period, as a result of increases in loan application rates from blacks during the latter half of the period, and of steady improvements in loan approval rates for black applicants. Some increases were seen in the proportion of applications attracted to lower-income tracts. Black loan applicants became more likely to apply for a loan in a predominantly white tract. A detailed spatial analysis of loan application patterns suggests that trends towards greater residential integration have accompanied recent mortgage market reforms.
Housing and Highway Planning in Israel: An Environmental Debate
Authors: Shmueli Deborah F.
Published: July 2002

The interrelated planning issues of housing and transport are subjects of controversy in Israel, as the country prepares for a population increase of 2.5 million by the year 2020. The debate is framed by the options for each—in housing, high-rise versus mixed-height building ; for the proposed National Highway, its desirability and, if implemented, the route. The author urges a judicious mix of low- and medium-rise housing channelled toward the periphery of the country, rather than the high-rise, high-density concentration that government policy currently encourages. Closely tied to planning for housing, is the strategy to be used in timing the construction of the Highway segments and locating their interchanges. Changing the sequencing of construction of the proposed National Highway to begin in the periphery instead of in the densely populated centre, would encourage development in areas of greater land availability.
Immigration, Spatial Segregation and Housing Segmentation of Immigrants in Metropolitan Stockholm, 1960-95
Authors: Murdie Robert A. , Borgegard Lars-Erik
Published: July 2002

Immigration policy and the origins of immigrants coming to Sweden have changed dramatically during the post-World War Two period. During the same period, changes in housing policy have affected the type of accommodation available to immigrants and refugees. It is within the context of these and other changes that we develop a model of the driving forces behind spatial segregation and housing segmentation in Sweden and document and evaluate shifts in the spatial segregation and housing segmentation of immigrants in the Stockholm region between 1960 and 1995.
Changing a Decision Taken under Uncertainty: The Case of the Criminal's Location Choice
Authors: Deutsch Joseph , Epstein Gil S.
Published: July 2002

In this paper we analyse the allocation of criminal activity over the metropolitan area over time. At each period of time, the criminal must choose in which area to commit his/her next offence. The criminal's expectations regarding his/her utility as a function of the probability to be apprehended are updated in the process of work. We find general conditions, under which the criminal determines his optimal location strategy. A direct policy implication of our model suggests that spillover effect is the result of changing police activities.
Technology and Industrial Policy for a Metropolis at the Threshold of the Global Economy: The Case of Haifa, Israel
Authors: Kipnis Baruch A.
Published: July 2002

The spatial concentration in Israel's core region of greater Tel Aviv, induced by Israel's entry to the post-industrial age and its affiliation with the global economy, has left, at least in the short run, the rest of the national territorial space, including metropolitan Haifa, the second-largest urban and economic agglomeration of the country, at the threshold of the global economy. Following an appraisal of the process of post-industrial functional upgrade and spatial concentration in the greater Tel Aviv region, possible avenues for a technological and industrial development policy for metropolitan Haifa are evaluated. This includes a presentation of probable alternative functional and spatial development strategies for the Haifa region and an appraisal of the inherent potentials and the anticipated roles to be played by the region's leading industries in instituting dynamic technological change.
Housing Investment and the Private Rental Sector in Australia
Authors: Beer Andrew
Published: July 2002

Over the past two decades, the private rental sector has changed its role within the Australian housing system as it has moved from being a tenure of transition, comprised principally of young households saving to enter home-ownership, to a tenure of long-term occupancy. Rising real house prices, soaring interest rates, changes in the nature of paid work and an increase in the number of household deaths through divorce or separation, has seen an increasing proportion of households either unable to enter home purchase, or unable to maintain their position within this tenure. In addition, access to publicly provided housing has declined. This paper considers the changing environment for private rental housing in Australia and examines the nature of investors and the size of their investment in the housing stock, as well as the impact of their investment strategies on the operation of the housing market.
The Southern Selkups of Tomsk Province before and after 1991
Authors: Sobanski Florian
Published: July 2002

The Selkups, a linguistic community known as Ostyak Samoyeds until the middle of the twentieth century, currently exist in two separate territorial groups in the regions of west-central and northwestern Siberia. In all, 3,612 people identified themselves as Selkups in the last Soviet census of 1989. Since there is great divergence in dialects among the various groups, some specialists suggest classifying them as three different languages: Northern, Central, and Southern Selkup. Here the Selkups of Tomsk province, who speak the central and southern dialects, will be referred to collectively as Southern Selkups.
Attention and Planning in Older Adults
Authors: Martin Mike , Ewert Otto
Published: July 2002

In a study with 48 adults between 65 and 97 years of age, we examined the influence of working memory, inhibitory efficiency, and attentional flexibility on the ability to solve efficiently a complex planning task: 26 of the subjects were living independently in their own home, and 22 subjects were recruited from nursing homes. Subjects first participated in a number of cognitive ability tests. They then had to plan a trip for a group of 20 people. The results indicate that inhibitory efficiency combined with the flexible use of attentional resources can account for substantial amounts of variance in the planning task. The results support the view that chronological age does not necessarily predict the performance in rather complex cognitive tasks like planning. The data also point at the possibility that deficits in one information-processing component can be compensated by other information-processing components that improve or remain stable in older adults. In order to predict adjustment to everyday contexts it might be necessary to consider individual, differentiated patterns of performance in a variety of basic information-processing components.
Infant and Preschool Mental and Verbal Abilities: How Are Infant Scores Related to Preschool Scores?
Authors: Molfese Victoria J. , Acheson Shawn
Published: July 2002

The present study examined two different systems for creating subscales for the Bayley Mental Development Index. The purpose was to determine how performance on Bayley MDI subscales at 1 and 2 years of age is related to performance on the Standford-Binet IV at 3 through 5 years of age. The purpose was also to determine how the correlations for global and specific skill scores change as time intervals between assessment points increase. The results show that first year MDI and subscale scores were weak correlates of two-year MDI and subscale scores and preschool scores on the Stanford-Binet. Stronger correlations were found between two-year scores and Stanford-Binet IQ and Verbal Reasoning scores. The data show similar stabilities between the measures of global functioning (MDI and IQ), and between early and later measures of verbal abilities beginning after 2 years of age.
Issues in Testing for Processing Capacity: Portrait of Convergent Validity with Oblique Rotations in the Background
Authors: Morra Sergio , Scopesi Alda
Published: July 2002

Commenting on a note by Steven Pulos, it is argued that a relationship between processing capacity and field independence, reported by Case and Globerson (1974) and Morra and Scopesi (1988), is compatible with the view that field independence tests are also demanding in terms of processing capacity. This does not imply that one should refrain from using a battery of tests in measuring M capacity. It is also noted that our previous research emphasised convergent validity because of current rhetorical needs, and we agree with Pulos that the nature of the relationship between processing capacity and other abilities deserves to be investigated more deeply.
The Goodness of Fit in Autonomy Timetable Expectations between Asian-American Late Adolescents and their Parents
Authors: Juang Linda P. , Lerner Jacqueline V. , McKinney John P. , von Eye Alexander
Published: July 2002

The purpose of this study was to examine the goodness of ”t of autonomy timetable expectations between Asian-American late adolescents and their parents. The “goodness of ”t” model (Lerner & Lerner, 1983; Thomas & Chess, 1977) was used as a framework to guide this study. All 99 Asian-American late adolescents completed self-report questionnaires. Results indicate that, overall, late adolescents would have liked to experience an earlier timetable of autonomy than their parents had allowed. However, there was variation in the sample, that is, there were some adolescents who did not want a different timetable than they were allowed. Also, it was found that the goodness of ”t between the autonomy timetable that adolescents would have liked and what their parents had allowed was a better predictor of adolescent adjustment than simply knowing the timetable of autonomy that adolescents had actually experienced. Late adolescents who experienced a good ”t with perceived parental expectations of autonomy reported higher levels of self-esteem and emotional closeness to their parents, and lower levels of depression, behaviour misconduct, and insecurity with parents, compared to their poor ”tting counterparts. It is proposed that the concept of “goodness of ”t” is a useful framework for the investigation of autonomy development, and subsequent adjustment in Asian-American late adolescents.
New directions in the genetic mechanisms underlying nicotine addiction
Authors: MunafÓ Marcus , Johnstone Elaine , Murphy Michael , Walton Robert
Published: July 2002

Major advances have been made in understanding nicotine addiction and smoking behaviour in recent years. In particular, evidence for the relative importance of genetic and environmental effects on smoking initiation and persistence has emerged from behaviour genetic studies. These data have supported evidence from molecular genetic studies for the role of particular candidate genes in tobacco dependence. Studies of the personality correlates of smoking behaviour suggest that these factors mediate the association between genetics and smoking initiation, while learning models of nicotine addiction suggest a role for dopaminergic genes in facilitating neuroadaptations associated with smoking persistence and development of nicotine dependence. Integrating these different avenues of research represents one of the most interesting and potentially fruitful ventures in the treatment of tobacco dependence.
Elevation of the soft palate in speech and swallowing in normal female participants and females with motor neuron disease: an innovative procedure for measuring palatal elevation
Authors: Perry Alison , Anderson Karen , Lean Ruth , Cotton Susan
Published: July 2002

The aim was to measure the angle of elevation of the soft palate during the separate conditions of swallowing of pudding, swallowing of liquid and during production of ‘may/pay’, using videofluoroscopy and innovative computer software. We then determined whether soft palate elevation (as reflected in measures of an angle) differed in those separate conditions. Twelve female participants were studied, aged 40−70 years. The trends observed were that the highest soft palate elevation was displayed in the liquid‐swallowing condition and the lowest soft palate elevation was displayed in the speech conditions. The results did not reach statistical significance, but the findings support the suggestions of Rubesin et al. (1987) and Fritzell (1969) that soft palate elevation is higher during swallowing than during speech. This same method was then used to measure soft palate elevation under the same three conditions in nine females, all aged >40 years, who had motor neuron disease. Again, the highest soft palate elevation was displayed when swallowing liquid, but this time the lowest elevation occurred when swallowing pudding. Owing to small numbers, results did not reach statistical significance, but the trends may be important to replicate in a larger study. This pilot study developed a comprehensive and accurate method of measuring the soft palate elevation using digitization and computer software.
Characteristics Of Children Attending Language Units In England: A National Study Of 7‐Year‐Olds
Authors: Conti‐Ramsden Gina , Botting Nicola
Published: July 2002

The present investigation examined the characteristics of 7‐year‐old children attending language units in England. The study involved 242 participants who represented a randomized sample of all 7‐year‐old children spending 50% of more of the school week in a language unit. Results are discussed in terms of the following questions: what is the non‐verbal ability of children attending language units?; do children attending language units fit the discrepancy criteria between verbal and non‐verbal ability diagnostic of specific language impairment (SLI)?; and what types of language diffi culties do children with SLI attending language units have?
Laminin-induced Clustering of Dystroglycan on Embryonic Muscle Cells: Comparison with Agrin-induced Clustering
Authors: Cohen Monroe W. , Jacobson Christian , Yurchenco Peter D. , Morris Glenn E. , Carbonetto Salvatore
Published: July 2002

The effect of laminin on the distribution of dystroglycan (DG) and other surface proteins was examined by fluorescent staining in cultures of muscle cells derived from Xenopus embryos. Western blotting confirmed that previously characterized antibodies are reactive in Xenopus. In control cultures, αDG, βDG, and laminin binding sites were distributed as microclusters (<1 μm2 in area) over the entire dorsal surface of the muscle cells. Treatment with laminin induced the formation of macroclusters (1–20 μm2), accompanied by a corresponding decline in the density of the microclusters. With 6 nM laminin, clustering was apparent within 150 min and near maximal within 1 d. Laminin was effective at 30 pM, the lowest concentration tested. The laminin fragment E3, which competes with laminin for binding to αDG, inhibited laminin-induced clustering but did not itself cluster DG, thereby indicating that other portions of the laminin molecule in addition to its αDG binding domain are required for its clustering activity. Laminin-induced clusters also contained dystrophin, but unlike agrin-induced clusters, they did not contain acetylcholine receptors, utrophin, or phosphotyrosine, and their formation was not inhibited by a tyrosine kinase inhibitor. The results reinforce the notion that unclustered DG is mobile on the surface of embryonic muscle cells and suggest that this mobile DG can be trapped by at least two different sets of molecular interactions. Laminin self binding may be the basis for the laminin-induced clustering.
Caspase Cleavage of Keratin 18 and Reorganization of Intermediate Filaments during Epithelial Cell Apoptosis
Authors: Caulín Carlos , Salvesen Guy S. , Oshima Robert G.
Published: July 2002

Keratins 8 (K8) and 18 (K18) are major components of intermediate filaments (IFs) of simple epithelial cells and tumors derived from such cells. Structural cell changes during apoptosis are mediated by proteases of the caspase family. During apoptosis, K18 IFs reorganize into granular structures enriched for K18 phosphorylated on serine 53. K18, but not K8, generates a proteolytic fragment during drug- and UV light–induced apoptosis; this fragment comigrates with K18 cleaved in vitro by caspase-6, -3, and -7. K18 is cleaved by caspase-6 into NH2-terminal, 26-kD and COOH-terminal, 22-kD fragments; caspase-3 and -7 additionally cleave the 22-kD fragment into a 19-kD fragment. The cleavage site common for the three caspases was the sequence VEVD/A, located in the conserved L1-2 linker region of K18. The additional site for caspases-3 and -7 that is not cleaved efficiently by caspase-6 is located in the COOH-terminal tail domain of K18. Expression of K18 with alanine instead of serine at position 53 demonstrated that cleavage during apoptosis does not require phosphorylation of serine 53. However, K18 with a glutamate instead of aspartate at position 238 was resistant to proteolysis during apoptosis. Furthermore, this cleavage site mutant appears to cause keratin filament reorganization in stably transfected clones. The identification of the L1-2 caspase cleavage site, and the conservation of the same or very similar sites in multiple other intermediate filament proteins, suggests that the processing of IFs during apoptosis may be initiated by a similar caspase cleavage.
Laminin-induced Acetylcholine Receptor Clustering: An Alternative Pathway
Authors: Sugiyama J.E. , Glass D.J. , Yancopoulos G.D. , Hall Z.W.
Published: July 2002

The induction of acetylcholine receptor (AChR) clustering by neurally released agrin is a critical, early step in the formation of the neuromuscular junction. Laminin, a component of the muscle fiber basal lamina, also induces AChR clustering. We find that induction of AChR clustering in C2 myotubes is specific for laminin-1; neither laminin-2 (merosin) nor laminin-11 (a synapse-specific isoform) are active. Moreover, laminin-1 induces AChR clustering by a pathway that is independent of that used by neural agrin. The effects of laminin-1 and agrin are strictly additive and occur with different time courses. Most importantly, laminin- 1–induced clustering does not require MuSK, a receptor tyrosine kinase that is part of the receptor complex for agrin. Laminin-1 does not cause tyrosine phosphorylation of MuSK in C2 myotubes and induces AChR clustering in myotubes from MuSK−/− mice that do not respond to agrin. In contrast to agrin, laminin-1 also does not induce tyrosine phosphorylation of the AChR, demonstrating that AChR tyrosine phosphorylation is not required for clustering in myotubes. Laminin-1 thus acts by a mechanism that is independent of that used by agrin and may provide a supplemental pathway for AChR clustering during synaptogenesis.
Dilation of the Human Immunodeficiency Virus–1 Envelope Glycoprotein Fusion Pore Revealed by the Inhibitory Action of a Synthetic Peptide from gp41
Authors: Muñoz-Barroso Isabel , Durell Stewart , Sakaguchi Kazuyasu , Appella Ettore , Blumenthal Robert
Published: July 2002

We have monitored fusion between cell pairs consisting of a single human immunodeficiency virus–1 (HIV-1) envelope glycoprotein–expressing cell and a CD4+ target cell, which had been labeled with both a fluorescent lipid in the membrane and a fluorescent solute in the cytosol. We developed a new three-color assay to keep track of the cell into which fluorescent lipids and/or solutes are redistributed. Lipid and solute redistribution occur as a result of opening a lipid-permissive fusion pore and a solute-permissive fusion pore (FPS), respectively. A synthetic peptide (DP178) corresponding to residues 643–678 of the HIV-1LAI gp120-gp41 sequence (Wild, C.T., D.C. Shugars, T.K. Greenwell, C.B. McDanal, and T.J. Matthews. 1994. Proc. Natl. Acad. Sci. USA. 91:12676–12680) completely inhibited FPS at 50 ng/ml, whereas at that concentration there was 20–30% fusion activity measured by the lipid redistribution. The differences detected in lipid mixing versus contents mixing are maintained up to 6 h of coculture of gp120-41–expressing cells with target cells, indicating that DP178 can “clamp” the fusion complex in the lipid mixing intermediate for very long time periods. A peptide from the NH2-terminal of gp41, DP107, inhibited HIV-1LAI gp120-gp41–mediated cell fusion at higher concentrations, but with no differences between lipid and aqueous dye redistribution at the different inhibitor concentrations. The inhibition of solute redistribution by DP178 was complete when the peptide was added to the fusion reaction mixture during the first 15 min of coculture. We have analyzed the inhibition data in terms of a fusion pore dilation model that incorporates the recently determined high resolution structure of the gp41 core.
Cholesterol Is Required for Surface Transport of Influenza Virus Hemagglutinin
Authors: Keller Patrick , Simons Kai
Published: July 2002

Transport from the TGN to the basolateral surface involves a rab/N-ethylmaleimide–sensitive fusion protein (NSF)/soluble NSF attachment protein (SNAP)/SNAP receptor (SNARE) mechanism. Apical transport instead is thought to be mediated by detergent-insoluble sphingolipid–cholesterol rafts. By reducing the cholesterol level of living cells by 60–70% with lovastatin and methyl-β-cyclodextrin, we show that the TGN-to-surface transport of the apical marker protein influenza virus hemagglutinin was slowed down, whereas the transport of the basolateral marker vesicular stomatitis virus glycoprotein as well as the ER-to-Golgi transport of both membrane proteins was not affected. Reduction of transport of hemagglutinin was accompanied by increased solubility in the detergent Triton X-100 and by significant missorting of hemagglutinin to the basolateral membrane. In addition, depletion of cellular cholesterol by lovastatin and methyl-β-cyclodextrin led to missorting of the apical secretory glycoprotein gp-80, suggesting that gp-80 uses a raft-dependent mechanism for apical sorting. Our data provide for the first time direct evidence for the functional significance of cholesterol in the sorting of apical membrane proteins as well as of apically secreted glycoproteins.
Dynamic Interaction of PTPμ with Multiple Cadherins In Vivo
Authors: Brady-Kalnay Susann M. , Mourton Tracy , Nixon Joseph P. , Pietz Gregory E. , Kinch Michael , Chen Haiyan , Brackenbury Robert , Rimm David L. , Del Vecchio Robert L. , Tonks Nicholas K.
Published: July 2002

There is a growing body of evidence to implicate reversible tyrosine phosphorylation as an important mechanism in the control of the adhesive function of cadherins. We previously demonstrated that the receptor protein tyrosine phosphatase PTPμ associates with the cadherin–catenin complex in various tissues and cells and, therefore, may be a component of such a regulatory mechanism (Brady-Kalnay, S.M., D.L. Rimm, and N.K. Tonks. 1995. J. Cell Biol. 130:977– 986). In this study, we present further characterization of this interaction using a variety of systems. We observed that PTPμ interacted with N-cadherin, E-cadherin, and cadherin-4 (also called R-cadherin) in extracts of rat lung. We observed a direct interaction between PTPμ and E-cadherin after coexpression in Sf9 cells. In WC5 cells, which express a temperature-sensitive mutant form of v-Src, the complex between PTPμ and E-cadherin was dynamic, and conditions that resulted in tyrosine phosphorylation of E-cadherin were associated with dissociation of PTPμ from the complex. Furthermore, we have demonstrated that the COOH-terminal 38 residues of the cytoplasmic segment of E-cadherin was required for association with PTPμ in WC5 cells. Zondag et al. (Zondag, G., W. Moolenaar, and M. Gebbink. 1996. J. Cell Biol. 134: 1513–1517) have asserted that the association we observed between PTPμ and the cadherin–catenin complex in immunoprecipitates of the phosphatase arises from nonspecific cross-reactivity between BK2, our antibody to PTPμ, and cadherins. In this study we have confirmed our initial observation and demonstrated the presence of cadherin in immunoprecipitates of PTPμ obtained with three antibodies that recognize distinct epitopes in the phosphatase. In addition, we have demonstrated directly that the anti-PTPμ antibody BK2 that we used initially did not cross-react with cadherin. Our data reinforce the observation of an interaction between PTPμ and E-cadherin in vitro and in vivo, further emphasizing the potential importance of reversible tyrosine phosphorylation in regulating cadherin function.
The Juxtamembrane Region of the Cadherin Cytoplasmic Tail Supports Lateral Clustering, Adhesive Strengthening, and Interaction with p120ctn
Authors: Yap Alpha S. , Niessen Carien M. , Gumbiner Barry M.
Published: July 2002

Cadherin cell–cell adhesion molecules form membrane-spanning molecular complexes that couple homophilic binding by the cadherin ectodomain to the actin cytoskeleton. A fundamental issue in cadherin biology is how this complex converts the weak intrinsic binding activity of the ectodomain into strong adhesion. Recently we demonstrated that cellular cadherins cluster in a ligand-dependent fashion when cells attached to substrata coated with the adhesive ectodomain of Xenopus C-cadherin (CEC1-5). Moreover, forced clustering of the ectodomain alone significantly strengthened adhesiveness (Yap, A.S., W.M. Brieher, M. Pruschy, and B.M. Gumbiner. Curr. Biol. 7:308–315). In this study we sought to identify the determinants of the cadherin cytoplasmic tail responsible for clustering activity. A deletion mutant of C-cadherin (CT669) that retained the juxtamembrane 94–amino acid region of the cytoplasmic tail, but not the β-catenin–binding domain, clustered upon attachment to substrata coated with CEC1-5. Like wild-type C-cadherin, this clustering was ligand dependent. In contrast, mutant molecules lacking either the complete cytoplasmic tail or just the juxtamembrane region did not cluster. The juxtamembrane region was itself sufficient to induce clustering when fused to a heterologous membrane-anchored protein, albeit in a ligand-independent fashion. The CT669 cadherin mutant also displayed significant adhesive activity when tested in laminar flow detachment assays and aggregation assays. Purification of proteins binding to the juxtamembrane region revealed that the major associated protein is p120ctn. These findings identify the juxtamembrane region of the cadherin cytoplasmic tail as a functionally active region supporting cadherin clustering and adhesive strength and raise the possibility that p120ctn is involved in clustering and cell adhesion.
The Laminin–Nidogen Complex is a Ligand for a Specific Splice Isoform of the Transmembrane Protein Tyrosine Phosphatase LAR
Authors: O'Grady Pauline , Thai Tran Cam , Saito Haruo
Published: July 2002

Leukocyte antigen–related protein (LAR) is a prototype for a family of transmembrane protein tyrosine phosphatases whose extracellular domain is composed of three Ig and several fibronectin type III (FnIII) domains. Complex alternative splicing of the LAR-FnIII domains 4–8 has been observed. The extracellular matrix laminin–nidogen complex was identified as a ligand for the LAR-FnIII domain 5 (Fn5) using a series of GST-LAR-FnIII domain fusion proteins and testing them in in vitro ligand-binding assays. LAR– laminin–nidogen binding was regulated by alternative splicing of a small exon within the LAR-Fn5 so that inclusion of this exon sequence resulted in disruption of the laminin–nidogen-binding activity. Long cellular processes were observed when HeLa cells were plated on laminin–nidogen, but not when plated on a fibronectin surface. Indirect immunofluorescent antibody staining revealed high expression of LAR in a punctate pattern, throughout the length of these cellular processes observed on laminin–nidogen. Antibody-induced cross-linking of LAR inhibited formation of these cellular processes, and inhibition was correlated with changes in cellular actin cytoskeletal structure. Thus, LAR–laminin–nidogen binding may play a role in regulating cell signaling induced by laminin–nidogen, resulting in cell morphological changes.