bluuebunny/crossref_metadata_2025 huggingface dataset:
Concept of a liquid-crystal polarization beamsplitter based on binary phase gratings
Authors: Park Jae-Hong , Yu Chang-Jae , Kim Jinyool , Chung Sung-Yeop , Lee Sin-Doo
Published: September 2003

We propose a concept of fabricating a liquid-crystal (LC) polarization beamsplitter based on binary phase gratings. The binary grating phenomenon in the LC layer physically originates from two different interfacial interactions at periodically alternating domain boundaries. The periodic LC domains are produced by employing a single-step photoalignment technique which precisely controls the surface orientation of the LC molecules in an alternating homeotropic and hybrid aligned geometry. In this binary configuration, the polarization-separating phase modulation of an input beam is achieved in a wide range of the wavelengths under an applied voltage. The experimental data are consistent with our linearly graded binary model.
Electrical contacts to ultrananocrystalline diamond
Authors: Gerbi J. E. , Auciello O. , Birrell J. , Gruen D. M. , Alphenaar B. W. , Carlisle J. A.
Published: September 2003

The contact behavior of various metals on n-type nitrogen-doped ultrananocrystalline diamond (UNCD) thin films has been investigated. The influences of the following parameters on the current–voltage characteristics of the contacts are presented: (1) electronegativity and work function of various metals, (2) an oxidizing acid surface cleaning step, and (3) oxide formation at the film/contact interface. Near-ideal ohmic contacts are formed in every case, while Schottky barrier contacts prove more elusive. These results counter most work discussed to date on thin diamond films, and are discussed in the context of the unique grain-boundary conductivity mechanism of the nitrogen-doped UNCD.
Continuous-wave distributed-feedback quantum-cascade lasers on a Peltier cooler
Authors: Aellen Thierry , Blaser Stéphane , Beck Mattias , Hofstetter Daniel , Faist Jérôme , Gini Emilio
Published: September 2003

Continuous-wave operation of λ∼9 μm distributed-feedback quantum-cascade lasers is reported up to a temperature of 260 K. Single-frequency emission with a side mode suppression ratio of ⩾27 dB and with a tuning range of 5 cm−1 between 200 and 245 K (a tunability of −0.078 cm−1/K and −0.764 cm−1/W) is obtained for the junction-down mounted buried heterostructure devices. Uncoated lasers display an output power of up to 18 mW at 180 K and still 1 mW at 250 K. Lasers with high-reflection coated facets could be operated up to 260 K.
Room-temperature operation of InGaAs/AlInAs quantum cascade lasers grown by metalorganic vapor phase epitaxy
Authors: Green R. P. , Krysa A. , Roberts J. S. , Revin D. G. , Wilson L. R. , Zibik E. A. , Ng W. H. , Cockburn J. W.
Published: September 2003

We report the room-temperature operation of λ≈8.5 μm InGaAs/AlInAs quantum cascade lasers, grown by low-pressure metalorganic vapor phase epitaxy. The necessary control of interfacial abruptness and layer thicknesses was achieved by the use of individually purged vent/run valves and a growth rate of 0.8 μm/h for the active region. Low-temperature threshold current densities of ∼1.5 kA cm−2 and a maximum operating temperature of 290 K have been measured in pulsed operation. These values are comparable with those reported for structures of a similar design grown using molecular beam epitaxy.
Tunable organic transistors that use microfluidic source and drain electrodes
Authors: Maltezos George , Nortrup Robert , Jeon Seokwoo , Zaumseil Jana , Rogers John A.
Published: September 2003

This letter describes a type of transistor that uses conducting fluidic source and drain electrodes of mercury which flow on top of a thin film of the organic semiconductor pentacene. Pumping the mercury through suitably designed microchannels changes the width of the transistor channel and, therefore, the electrical characteristics of the device. Measurements on transistors with a range of channel lengths reveal low contact resistances between mercury and pentacene. Data collected before, during, and after pumping the mercury through the microchannels demonstrate reversible and systematic tuning of the devices. This unusual type of organic transistor has the potential to be useful in plastic microfluidic devices that require active elements for pumps, sensors, or other components. It also represents a noninvasive way to build transistor test structures that incorporate certain classes of chemically and mechanically fragile organic semiconductors.
Microstructure of lateral epitaxial overgrown InAs on (100) GaAs substrates
Authors: Suryanarayanan G. , Khandekar Anish A. , Kuech Thomas F. , Babcock Susan E.
Published: September 2003

Substantial defect reduction was achieved in InAs/GaAs by lateral epitaxial overgrowth in which InAs was grown on mask-patterned (100) GaAs with stripe-shaped windows of various widths by metalorganic chemical vapor deposition. The InAs growth morphology, crystal quality, and microstructure were evaluated using double-crystal x-ray rocking curves and scanning and transmission electron microscopy. The microstructure of the InAs grown on mask-free control samples was comprised of micron-scale misoriented grains and dislocations at a density of 1011 cm−2. As the width of the mask openings decreased to 0.8 μm, the rocking curves narrowed, grain boundaries disappeared and the dislocation density decreased to <107 cm−2. The distribution of the remaining defects suggests substantial changes in microstructural development when the window width is ≲1 μm.
Additive jet printing of polymer thin-film transistors
Authors: Paul Kateri E. , Wong William S. , Ready Steven E. , Street Robert A.
Published: September 2003

Organic thin-film transistors were fabricated by direct patterning of solution-processable semiconductors consisting of either poly(9,9′-dioctyl-fluorene-co-bithiophene) or a regioregular poly(thiophene). Acoustic ink-jet printing was used to deposit the polymeric semiconductor onto patterned metal source-drain contacts. Printed and spin coated transistors performed identically. The regioregular poly(thiophene) exhibited a mobility of 0.1 cm2 V–1 s−1, on-off current ratios of ∼106 and low threshold voltage.
Young modulus dependence of nanoscopic friction coefficient in hard coatings
Authors: Riedo Elisa , Brune Harald
Published: September 2003

We present an atomic force microscope study of nanoscopic sliding friction on diamond, diamond-like carbon, and on three CrN thin films with varying hardness obtained by different growth temperatures. For the CrN films, we show that the changes in the friction coefficient can be traced back to variations of the Young modulus. More generally, we show for all samples investigated and in wearless regime, that the nanoscopic friction coefficient is directly linked to the Young modulus.
Dielectric properties of organic monolayers directly bonded on silicon probed by current sensing atomic force microscope
Authors: Zhao Jianwei , Uosaki Kohei
Published: September 2003

The dielectric properties of alkyl monolayers with various chain lengths [CH3(CH2)n−1- (n=12, 14, 16, and 18)] covalently bonded to a hydrogen terminated n-type silicon (111) surface in a nanoscale region were evaluated using current sensing atomic force microscopy (AFM). A reliable electrical contact between the alkyl monolayers and the metal-coated AFM tip was achieved under slight stress. At a force less than 2 nN, current sharply increased as the bias was scanned over a critical value, showing that breakdown took place. The breakdown voltage linearly depended on the chain length of the alkyl monolayers and the dielectric strength of 2.0 GV/m was derived from the slope of this relation.
Microstructural influences on stress migration in electroplated Cu metallization
Authors: Sekiguchi A. , Koike J. , Maruyama K.
Published: September 2003

Stress migration in advanced Cu interconnects leads to device failure and to poor production throughput. In this work, microstructural effects on stress-migration resistance were investigated in two types of electroplated Cu metallization having a 〈111〉 texture and a random texture. Transmission electron microscopy showed incoherent twins in the 〈111〉 textured films whereas coherent twins in the random textured films. The incoherent twins were found to accompany stress-induced voids because of a weak bonding at twin interfaces. Unlike conventional Al interconnects, a strong 〈111〉 texture should be avoided to minimize stress-migration failure in Cu interconnects.
Mechanism of reliability failure in Cu interconnects with ultralow-κ materials
Authors: Michael N. L. , Kim Choong-Un , Gillespie P. , Augur R.
Published: September 2003

This letter presents evidence of an oxidation-driven failure mechanism in Cu interconnects integrated with ultralow-κ materials. It is found that the open pore structure of ultralow-κ materials allows oxidants in the ambient to reach the interconnect structure and induce oxidation of Cu. In contrast to a normal oxidation process where Cu is in contact with the oxidant, oxidation is controlled by the outdiffusion of Cu through the barrier layers, Ta and SiCN, to form Cu oxide in the pores of the dielectric material. The loss of Cu by outdiffusion induces extensive voiding and subsequent failure in Cu interconnects.
Kinetics of hydrogen atoms in high-density CF4/H2 plasmas studied by (2+1)-photon laser-induced fluorescence spectroscopy
Authors: Sasaki K. , Okamoto M.
Published: September 2003

We measured the distribution of absolute H atom density in high-density, low-pressure CF4 plasmas with the addition of H2 by (2+1)-photon laser-induced fluorescence spectroscopy. The H atom density had hollow-shaped distributions, i.e., the H atom density adjacent to the chamber wall was higher than that in the plasma column. In addition, when the chamber wall was covered with hydrogenated fluorocarbon film, we detected H atoms without the addition of feedstock H2. These experimental results indicate surface production of H atoms from hydrogenated fluorocarbon film. The surface production rate was sensitive to the property of fluorocarbon film. When the property of fluorocarbon film was unified, the surface production rate increased linearly with the pressure of feedstock H2, suggesting a recycling process of H atoms between gas phase and fluorocarbon film as a mechanism of plasma–surface interaction in CF4/H2 plasmas.
Behavior of hydrogen in high dielectric constant oxide gate insulators
Authors: Peacock P. W. , Robertson J.
Published: September 2003

Interstitial hydrogen is calculated to act as a shallow donor in the candidate high dielectric constant (k) gate oxides ZrO2, HfO2, La2O3, Y2O3, TiO2, SrTiO3, and LaAlO3 but is deep in the oxides SiO2, Al2O3, ZrSiO4, HfSiO4, and SrZrO3. This may account for the change of sign of fixed charge in oxides, from negative in Al2O3 to positive in HfO2.
Elastic responses to different electric-field directions in relaxor ferroelectric Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 single crystals
Authors: Ko Jae-Hyeon , Kim Do Han , Kojima Seiji
Published: September 2003

Micro-Brillouin scattering was applied to relaxor-based complex perovskite Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 (PZN–9% PT) single crystals during a polarization switching under two different electric-field directions along 〈111〉 and 〈101〉. Brillouin spectra consisted of one longitudinal and two transverse acoustic modes, and the Brillouin shift and the full width at half maximum of these modes showed clear changes near the coercive field (Ec) where the polarization reversal occurred. In particular, the lowest transverse mode was the most sensitive to Ec. In the case of 〈111〉-poled crystals the Brillouin spectrum exhibited an asymmetric shape in a narrow electric-field range near Ec due to a coupling between the lowest transverse mode and a central peak. In the case of 〈101〉-poled crystals, the lowest transverse mode showed an abrupt softening at Ec and a slow recovery to the initial value upon further increasing the electric field. This may indicate the appearance of the monoclinic symmetry where the polarization can rotate freely toward the orthorhombic phase in the MB plane under the electric field along the 〈101〉 direction. The observation of no changes in the Brillouin spectra with decreasing the electric field seems to indicate that the PZN–9% PT crystal, poled under the field along 〈101〉, does not become rhombohedral, but remains in the induced orthorhombic phase upon the removal of the field.
Sonochemical modification of the superconducting properties of MgB2
Authors: Prozorov Tanya , Prozorov Ruslan , Snezhko Alexey , Suslick Kenneth S.
Published: September 2003

Ultrasonic irradiation of magnesium diboride slurries in decalin produces material with significant intergrain fusion. Sonication in the presence of Fe(CO)5 produces magnetic Fe2O3 nanoparticles embedded in the MgB2 bulk. The resulting superconductor–ferromagnet composite exhibits considerable enhancement of its magnetic hysteresis, which implies an increase of vortex pinning strength due to embedded magnetic nanoparticles.
Temperature stability for silicon-based photonic band-gap structures
Authors: Weiss S. M. , Molinari M. , Fauchet P. M.
Published: September 2003

A method for minimizing thermal effects on silicon-based photonic band-gap (PBG) structures is demonstrated. The reflectance resonance positions of as-anodized one-dimensional porous silicon (PSi) PBG microcavities exhibit 3 nm redshifts when heated up to 100 °C, which significantly alters the light propagation properties of the structures. By carefully controlling the oxidation conditions of the PSi microcavities, it is possible to reduce the shift to less than 0.5 nm. High-resolution x-ray diffraction experiments directly link variations of the silicon strain during heating to shifts of the reflectance resonance. The pressure change induced by the proper oxidation level can compensate for the effect of the temperature change and, thus, stabilize the resonance position.
Fabrication of stable wide-band-gap ZnO/MgO multilayer thin films
Authors: Bhattacharya P. , Das Rasmi R. , Katiyar R. S.
Published: September 2003

We report the fabrication of stable wide-band-gap (∼6 eV) ZnO/MgO multilayer thin films using pulsed-laser deposition on c-plane Al2O3 substrates. The thickness of ZnO layers was varied in the range of 0.75–2.5 nm inside the MgO host with a constant MgO thickness of 1 nm. With a decrease in the thickness of ZnO sublayers, abrupt structural transition from hexagonal to cubic phase was observed. The band gap of the films was found to be influenced by the crystalline structure of multilayer stacks. Thin films with hexagonal and cubic structure exhibited band-gap values of 3.5 and 6 eV, respectively. The x-ray photoelectron spectroscopy analysis confirmed that the Mg content of the films was about 40% and 60% in the hexagonal and cubic phases, respectively. Annealing at 750 °C did not influence the structural and optical properties of the ZnO/MgO multilayers.
Raman scattering in ZnO thin films doped with Fe, Sb, Al, Ga, and Li
Authors: Bundesmann C. , Ashkenov N. , Schubert M. , Spemann D. , Butz T. , Kaidashev E. M. , Lorenz M. , Grundmann M.
Published: September 2003

Polarized micro-Raman measurements were performed to study the phonon modes of Fe, Sb, Al, Ga, and Li doped ZnO thin films, grown by pulsed-laser deposition on c-plane sapphire substrates. Additional modes at about 277, 511, 583, and 644 cm−1, recently assigned to N incorporation [A. Kaschner et al., Appl. Phys. Lett. 80, 1909 (2002)], were observed for Fe, Sb, and Al doped films, intentionally grown without N. The mode at 277 cm−1 occurs also for Ga doped films. These modes thus cannot be related directly to N incorporation. Instead, we suggest host lattice defects as their origin. Further additional modes at 531, 631, and 720 cm−1 seem specific for the Sb, Ga, and Fe dopants, respectively. Li doped ZnO did not reveal additional modes.
Role of the indium–carbon interaction on In diffusion and activation in Si
Authors: La Magna Antonino , Scalese Silvia , Alippi Paola , Mannino Giovanni , Privitera Vittorio , Bersani Massimo , Zechner Christoph
Published: September 2003

We present a theoretical approach to the study of C influence on In diffusion and activation in Si. We consider a kick-out type model for the defect driven migration of both species, while we assume that InC complexes form by the interaction between the defect-impurity pairs and the substitutional species. Moreover, we introduce a double-level activation model in order to calculate the active fraction of the diffusion profiles. In parameters are derived both from ab initio calculations and from fitting the experimental diffusion profiles. The modeling is used in order to explain experimental data relative to In implanted into Si substrates containing different C contamination background.
Blue photoluminescence of α-Ga2S3 and α-Ga2S3:Fe2+ single crystals
Authors: Yoon Chang-Sun , Medina F. D. , Martinez L. , Park Tae-Young , Jin Moon-Seog , Kim Wha-Tek
Published: September 2003

α- Ga 2 S 3 and α-Ga2S3:Fe2+ single crystals were grown by the two-zone sublimation method. The optical energy gaps of α-Ga2S3 and α-Ga2S3:Fe2+ at 10 K were found to be 3.440 and 3.392 eV, respectively. From the absorption spectra of α-Ga2S3:Fe2+, the crystal field parameter Dq of 345 cm−1 and Racah parameters B of 700 and C of 3365 cm−1 were obtained for tetrahedral Fe2+ ions. From the photoluminescence spectra at 10 K, the blue and red emissions at 424 and 643 nm, respectively, for α-Ga2S3 and the violet and yellow emissions at 400 and 580 nm, respectively, for α-Ga2S3:Fe2+ were observed. All the emission lines observed in the photoluminescence spectra were identified.
Effect of helical-induced anisotropy on the magnetoinductance response of Co-based amorphous wires
Authors: Betancourt I. , Valenzuela R.
Published: September 2003

In this letter, the effect of helical anisotropy, induced by torsion strain, on the circular permeability μφ, of a vanishing negative magnetostrictive CoFeSiB wire is presented. As a function of a dc applied magnetic field, Hdc, μφ shows an asymmetric behavior dependent on the direction of the applied torsion strain: for counterclockwise torsion angles (−), a monotonous decrease in the μφ (Hdc) double peak magnetoimpedance response is observed together with a linear increase in the wire’s circular anisotropy field Hk. In contrast, for clockwise torsion angles (+), a gradual suppression of the μφ (Hdc) maxima was evident, for which a magnetic softening of the wire is assumed. Results are interpreted in terms of a counterbalance/enhancement effect of the wire’s circular anisotropy for + and − torsion angles, respectively.
Electron-beam-induced deposition using a subnanometer-sized probe of high-energy electrons
Authors: Mitsuishi K. , Shimojo M. , Han M. , Furuya K.
Published: September 2003

Electron-beam-induced deposition was performed to fabricate nanostructures using a subnanometer-sized probe of high-energy electrons emitted by a 200 kV transmission electron microscope equipped with a field emission gun. We fabricated nanometer-sized dots with a diameter of less than 5 nm, controlling their position and size by the introduction of a organometallic precursor gas near the substrate surface. The relation between the size of the deposit and the deposition time was studied, and, in addition, the effect of the substrate thickness was examined.
Housing Allowances in the US under Section 8 and in Other Countries: A Canadian Perspective
Authors: Steele Marion
Published: September 2003

Housing allowances are provided in the US by the federal government under Section 8 of the 1974 Housing and Community Development Act. This paper compares the design of Section 8 certificates and vouchers with that of Canadian housing allowances and with aspects of design in many other developed nations. Distinguishing elements of Section 8 are discussed: its minimum standards condition, its use of a three-way contract in which both the government housing agency and the tenant pays a private landlord, its availability to only a limited number of eligibles, the absence of a percentage-of-rent element in its formulas and the low required contribution of its recipients. It is argued on the basis of an array of diverse evidence that these characteristics lead to perverse housing consumption effects, stigma, rent inflation and unnecessary restrictions on recipient choice. The paper also addresses the standard objections to dropping the minimum standards condition and to incorporating a percentage-of-rent element in the formula.
The Potential Bias in Producer Service Employment Estimates: The Case of the Canadian Space Economy
Authors: Wernerheim C. Michael , Sharpe Christopher A.
Published: September 2003

Footloose information technology producer services are increasingly viewed as the new engines of regional growth and employment creation. The claim is often that appropriate government policy can engineer comparative advantage in that direction by means of judicious subsidisation. The evaluation of such claims relies on accurate statistical data. We argue that attempts to distinguish in survey data or official statistics the subset of services commonly (but unofficially) known as producer services from consumer and government services may result in a potential 'bias' with implications for public policy. An input-output model is developed for estimating this bias by decomposing service industry data into its producer and consumer services content. This method can give a truer estimate of the actual employment in producer services at various spatial levels. We find a systematic bias in official data and a non-systematic bias in survey data. The model is applicable to countries and regions for which input-output data are available.
European Integration and Local Capacities for Manufacturing Adjustment and Change: The Case of Spain
Authors: Hamilton F.E. Ian , Rodríguez-Pose Andrés
Published: September 2003

The southward enlargement of the European Community with the full accession of Spain and Portugal in 1986 and the creation of the Single Market in 1993 have opened up new opportunities for exports to the EU and have intensified competition with Spanish-made products in the rest of the EU. This paper hypothesises that local adjustment to European integration is conditioned by the comparative local advantages (or disadvantages) in human resources, nodality and external economies which can shape local capacity for the achievement of economies of scale in production, technological modernisation, the development of small and medium enterprises (SMEs) and business services. The capacities for these four dynamic processes are articulated through the interaction between the investment decisions of Spanish and foreign-owned firms and the local comparative advantages, and hence influence the capacity of localities to respond to European integration through trade creation and trade diversion.
Disability and the Open City
Authors: Gleeson Brendan
Published: September 2003

For at least three decades, the issue of physical accessibility has been a focus of analysis amongst some spatial scientists, including geographers, urban planners and architects. Whilst such 'conventional' access studies have assumed an important role as policy evaluation/ critique, their theoretical significance has been extremely limited. The understanding of accessibility, and the highly contested set of policy fields that regulates this, would be deepened if a wider range of socio-political theory was used to examine these issues. This paper contributes to the social theorisation of access by critically exploring how the 'reflexive modernisation' thesis of Ulrich Beck might be applied to the geographical understanding of disablement. The paper demonstrates how Beck's theoretical framework can be used to enrich understanding of the genesis and mediation of inaccessibility.
Reducing Residential Carbon Intensity: The New Role for English Local Authorities
Authors: McEvoy D. , Gibbs D.C. , Longhurst J.W.S.
Published: September 2003

The residential sector is a substantial source of CO2 in the UK, accounting for over 25 per cent of all end-use emissions. Improvements in energy efficiency are often cited as important elements of carbon reduction packages, with policy-makers emphasising the significant `untapped' potential of improved energy use in the home. The design and implementation of policies at a local level have a particularly important role to play, recognised by national government in their promotion of the 1995 Home Energy Conservation Act (HECA). The legislation places responsibility on local authorities to act as energy conservation authorities for all dwellings within their boundaries and to devise action plans for a 30 per cent reduction in energy use. Adopting a regional approach, this paper focuses on the HECA strategies of the 10 borough councils of Greater Manchester in the UK, examining the opportunities and constraints that face local authorities in their new role as 'strategic enablers'. Results indicate that greater collaboration, both between and within local authorities, would benefit the overall effectiveness of carbon reduction policies for Greater Manchester.
The Use of Architects
Authors: Hill Jonathan
Published: September 2003

Architecture is made by use and design. To use a building is to make it, either by physical transformation, such as moving walls or furniture, by inhabiting it in ways not previously imagined or by conceiving it anew. With a role equal in the formulation of architecture to that of the architect, the creative user either creates a new space or gives an existing one new meanings and uses contrary to established behaviour.
Assistive Technology and the Barrier-free City: A Case Study from Germany
Authors: Neumann Peter , Uhlenkueken Christoph
Published: September 2003

The paper investigates how far the state-of-the-art technology of the internet can contribute to the creation of a barrier-free city. The paper begins with a discussion of the general possibilities and potential of the internet for disabled people. This discussion is followed by a presentation of the significance of internet technologies for disabled people and urban development. The practical application of the approach will then be illustrated by means of a case study: the KOMM project in Muenster, Germany. The paper concludes with an evaluation of the potential and the limits of the internet for a barrier-free city.
Estimating Distance Gradients for Apartment Properties
Authors: Söderberg Bo , Janssen Christian
Published: September 2003

The effect of distance from the city centre on selling price, tax assessment and gross income is investigated for income property in proximity to the city centre. Hedonic estimation with a multiplicative model specification is used to estimate the relationship between property characteristics on the one hand and price, assessment and income on the other. The sample consists of centrally located apartment buildings in downtown Stockholm sold during a recent three-year period. The application is specific to Stockholm, but the methodology and the insights gained are general. The results include the estimation of price gradients for the dependent variables. The models are used for estimating the implicit capitalisation rates in the property market as a function of the distance to the centre. We also estimated where the market appears to place the city centre as implied by the observations. Although no rent gradient was found, we were able to detect a significant negative price gradient. The former is reasonable considering the rent control ordinances. The latter indicates the existence of a negative land rent gradient.
Globalising Singapore: Debating Transnational Flows in the City
Authors: Yeoh Brenda S. A. , Chang T.C.
Published: September 2003

Transnational practices and networks of capital, labour, business and commodity markets, political movements and cultural flows are both the products of, and catalyst for, contemporary globalisation processes. An important site where the analytical lens can be trained to examine the way in which the material processes and discourses of globalisation and transnationalism intersect lies in dominant cities of the world urban hierarchy. As key nodes in the economic, social and technological networks spanning the world space economy, these 'global cities' are also places in themselves, where the social, cultural and economic fabric is not only woven out of local elements, but also clearly involves a high density of transnational relationships. In this paper, we examine debates in Singapore focused on four categories of transnational flows: the transnational business class comprising highly mobile, highly skilled professional, managerial and entrepreneurial elites ; a large group of low-waged immigrants filling unskilled and semi-skilled niches in the urban service economy; expressive specialists who enliven the cultural and artistic scene; and world tourists attracted by the cosmopolitan ambience. Specifically, we give attention to the interdependence among these categories and assess the challenges which have to be addressed in Singapore's bid to develop 'best practices' for a 'cosmopolitan and creative' global city epitomising the essence of transnationalism while at the same time remaining a 'home' distinguished by a strong sense of local identity and community.
Growth Clusters in European Cities: An Integral Approach
Authors: van den Berg Leo , Braun Erik , van Winden Willem
Published: September 2003

This paper analyses and compares the dynamics of clusters in nine urban regions in Europe. The cluster perspective in the studying of growth processes in cities has added value because, increasingly, economic activities cross the boundaries of traditional economic sectors, as networks are becoming the leading organisational principle. The integral approach reveals that the performance and dynamics of clusters depend on cluster-specific conditions and, to a large extent, also on the general spatial-economic situation in the urban region and the quality of urban management.
Encouraging Walking: The Case of Journey-to-school Trips in Compact Urban Areas
Authors: Black Colin , Collins Alan , Snell Martin
Published: September 2003

An activity-based approach is used to analyse one specific short-trip purpose that has persistently frustrated transport analysts trying to induce more walk, cycle or public transport based trips. This study of the journey-to-school trip is motivated by a general consensus that, to effect a more sustainable transport system, there is a necessity to reduce car use (especially for short trips). Resistance to modal transfer from cars has been shown to be embedded in various psycho-social obstacles which are not readily teased out in orthodox econometric studies of travel demand. We report on an empirical study which fuses psychometric (construction of coping scales) and econometric analyses (logit analysis) in an attempt to uncover the psychological and sociological factors influencing modal choice, as well as the usual range of economic and demographic factors.
The Socio-spatial Construction of (In)accessible Public Toilets
Authors: Kitchin Rob , Law Robin
Published: September 2003

This paper examines the rights of disabled people to access public spaces in Western societies through an analysis of the provision of accessible public toilets in Ireland. Providing a critical analysis around the themes of social justice and citizenship, the investigation is based on an examination of present-day planning legislation, interviews conducted with 35 disabled people-19 in the Republic of Ireland and 16 in Northern Ireland—and a case study of one particular town, Newbridge, County Kildare, Ireland. These data reveal that in Ireland and the UK, planning legislation is weak and often not enforced. Accessible public toilets are few and far between; those that do exist are often poorly designed; and, this lack of provision severely delimits the daily spatial behaviour of disabled people. This lack of provision, it is argued, is expressive of a wider set of ableist power geometries and signifies that disabled people do not, as yet, have the same civil rights as non-disabled people.
Disabling Spatialities and the Regulation of a Visible Secret
Authors: Hawkesworth Marian
Published: September 2003

The greatest barriers to disabled people's inclusion in Western urbanised societies are often in the human-constructed environment which serves to exclude those whose bodily forms do not accord with specific conceptions of the normal body. This is particularly the case for people whose faces are negatively defined as being visibly different or categorised as 'facially disfigured'. This paper seeks to understand the (urban) geographies of people marked out by their perceived facial differences, specifically those defined as having acne. Drawing on original empirical material, the paper begins with a discussion of spatialities of disfigurement and how these are constitutive in the marginalisation of people with facial disfigurements from mainstream encounters and social relations. In the second section, it is demonstrated, through the use of narrative material, that problems of exclusion often arise from the attitudinal environment or those places which emphasise people's looks. A discussion follows of how feelings of shame and embarrassment about disfigurement often result in the withdrawal of individuals from mainstream spaces. The paper concludes by exploring the possibilities and problems in developing a politics of facial disfigurement.
An Exploration of Disability and the Development Process
Authors: Imrie Rob , Hall Peter
Published: September 2003

This paper explores the attitudes and practices of property developers and related agents in facilitating or constraining disabled people's access in the built environment. While acknowledging that the development process is characterised by a range of socio-institutional structures and relations which are insensitive to and ignorant of the needs of disabled people, we develop the proposition that developers' responses to disabled people are not necessarily invariant, predictable or reducible to a cost calculus. Rather, our evidence is illustrative of a heterogeneity of developers' attitudes and responses to the needs of disabled people. We conclude by commenting on practical and political possibilities for changing the social relations of the development process in ways which will incorporate access as an integral element of the design and development of the built environment.
Barriered and Bounded Places and the Spatialities of Disability
Authors: Imrie Rob
Published: September 2003

The papers in this Special Issue of Urban Studies consider, in their contrasting ways, the spatialities of disability and disabled people's barriered and bounded lives. The papers provide a range of insights into geographies of identity formation, while seeking to (re)assert the power of territoriality by putting "the place (and historical specificity) back into displacement" (Bammer, 1994, p. xiv; quoted in Pratt, 1998, p. 27). This introduction describes the main themes of the Special Issue and develops the argument that geographers and scholars of urban studies ought to develop a more active interest in the diverse and multiple geographies of disability.
Voucher Recipient Achievement of Improved Housing Conditions in the US: Do Moving Distance and Relocation Services Matter?
Authors: Varady David P. , Walker Carole C. , Wang Xinhao
Published: September 2003

When householders are vouchered-out from distressed, federally subsidised private developments in the US and receive moderate relocation counselling, does that counselling lead to a more intensive housing search, longer-distance moves and higher levels of housing satisfaction ? Multiple regression analysis was applied to a data-set containing survey and geographical information (for example, distance moved, median neighbourhood income level) for 201 voucher recipients in 4 cities. The analysis was used to determine if the use of relocation counselling services (as well as the type of services utilised) and distance moved helped to explain variations in housing satisfaction. Those who used counselling services were in fact more likely to be satisfied with their new home than were those who were unaware of these services. However, those who were aware of the services but did not use them fared as well as householders who used them. Counselling to help in dealings with landlords was the most influential type of relocation assistance vas à vis housing satisfaction. The distance householders moved played an insignificant role in the analysis. This finding undoubtedly reflects the fact that voucher recipients sought to remain in or close to their original neighbourhood to be near friends and relatives and familiar bus lines, and the fact that better housing units offering a greater sense of safety were available in the same neighbourhood or in neighbourhoods adjacent to the vouchered-out development. Implications for HUD's vouchering-out policy are discussed.
Participation, Empowerment and Sustainability: (How) Do the Links Work?
Authors: Lyons Michal , Smuts Carin , Stephens Anthea
Published: September 2003

This paper investigates the relationship between participation, empowerment and sustainability. Using the multisectoral and multicontextual experience of participation amassed in South Africa, both pre- and post- apartheid , we address two questions: does participation lead to empowerment; and does empowerment, in turn, lead to sustainability? Further, what external factors mediate and influence that relationship? Analysis shows that a relationship does exist and is contingent on a number of contextual factors, crucial to its success. Findings are discussed in terms of the international literature on community participation and local democracy, and policy implications are identified.
Administrative Practices in Russia's Housing Allowance Programme
Authors: Struyk Raymond J. , Puzanov Alexander S. , Kolodeznikova Anastasia
Published: September 2003

Implementation of housing allowances is an integral part of Russia's programme of systematic rent increases on state and municipal rental units which began in 1994. Because housing allowances constitute the country's first income-tested programme, its performance transcends the housing sector. Rents are being increased in steps to cover full operating costs by the middle of the current decade. Primary administrative responsibility for the programme rests at the local level. Since the rate at which rents increase is determined by each municipality, progress varies. Arguably, the quality of the programme's administration may influence acceptance of both the programme and broader economic and political reforms. Reported here are the results of a first-time assessment of the practices of local housing allowances offices (HAOs) who administer the programme. Field work included on-site reviews at 17 HAOs and analysis of about 1200 files of programme beneficiaries. For administrative practices covering such areas as the presence of written job descriptions, written guidelines for intake workers, generation of reports for higher-level authorities and setting standards for the routine review of files of applicants determined to be eligible for benefits, applicants rejected and time during which processing of approved cases should be completed, HAOs had a fair record. Generally, 2-4 of the studied offices failed the standards set out in the paper. However, frequent instances of incomplete record-keeping about HAO operations limit our conclusions and highlight an area definitely needing improvement. On the other hand, and important for programme credibility, errors in computing subsidies paid to beneficiaries were found to be universally very low. Overall, HAO performance is adequate but highly variable and improvements are clearly needed. The results can be interpreted as being consistent with HAO staff acceptance of housing allowances as a legitimate replacement for the previous broad entitlement to benefits that worked through controlled rents in state housing. The adequate operation of HAOs should work to strengthen popular support of broader economic and political reforms.
World Cities: A First Multivariate Analysis of their Service Complexes
Authors: Taylor Peter J. , Walker D.R.F.
Published: September 2003

In consideration of the local-global nexus it is commonplace to emphasise multiple 'locals'; in this paper, we introduce multiple 'globals' in the sense of differences in firm's globalisation strategies. Building upon the collection of a unique set of data showing advanced producer service office networks for 46 major firms in 55 world cities, the major dimensions of variability in this geography are explored using principal components analyses. An R-mode analysis shows similarities in firm's location patterns and 14 distinctive cross-city profiles of firms are identified. A key finding is that different producer services tend to have different cross-city profiles. A Q-mode analysis groups world cities in terms of similar corporate locations and 9 corporate service mixes are identified. A key finding is that most cities group into regional or interregional clusters; London and New York (but not Tokyo) are exceptional in forming their own distinctive 'global city' dimension. The overall conclusion is that world city formation, a core process of globalisation, has created a rich and informative geographical complexity. Since there is order to the complexity, the paper finishes with a multifarious research agenda derived from this first comprehensive, comparative analysis of world cities.
The Effects of Neighbourhoods on Size of Social Network of the Elderly and Loneliness: A Multilevel Approach
Authors: Moorer Peter , Suurmeijer Theo P. B. M.
Published: September 2003

Our goal was to find out how much influence neighbourhoods have on the size of the social network and loneliness of elderly people. The results show that the average size of the social network was 9, while the elderly had few feelings of loneliness. Neighbourhoods could at most explain 8 per cent of the size of social network and 6 per cent of loneliness. It is concluded that the elderly mostly have substantially sized social networks and few feelings of loneliness. Social networks and loneliness are probably more strongly related to the (psychological or social) characteristics of individuals and are hardly influenced by the characteristics of neighbourhoods.
Testing for Discrimination in Home Insurance: Results from New York City and Phoenix
Authors: Galster George , Wissoker Douglas , Zimmermann Wendy
Published: September 2003

This paper examines the results of a paired testing study of neighbourhood-based discrimination in the provision of quotes for home insurance in New York City and Phoenix, Arizona. We examine whether agents treated insurance-seekers buying their first homes in moderate-income, predominantly black or Hispanic-occupied neighbourhoods differently from insurance-seekers in comparable predominantly white neighbourhoods. The study examines differences in whether a quote is provided, the type of insurance and policy options offered and the premium quoted. Overall, of 10 key measures (5 for each city), only 1 (optional replacement cost coverage on personal property in Phoenix) showed a statistically significant difference consistent with discrimination. Testers in Hispanic neighbourhoods of Phoenix were quoted premiums 12 per cent higher than those offered to testers in white neighbourhoods. This difference, however, is in line with the price schedules for the state-approved rating territories in which the white and Hispanic homes were located.
Inclusion in Regeneration: A Place for Disabled People?
Authors: Edwards Claire
Published: September 2003

Since 1994, the Single Regeneration Budget (SRB) has been one of the British government's main policy tools in tackling inequality within Britain's cities. SRB partnerships seek collaboration between public, private and community sectors but, for some minority groups, such inclusionary intentions have proved to be more rhetoric than reality. Drawing on a questionnaire sent to 200 SRB partnerships across Britain, this paper addresses disabled people's involvement in SRB partnerships. As people who experience multiple forms of exclusion from contemporary society, it would seem imperative that they should have a stake in local regeneration initiatives. The paper explores the extent, form of and barriers to, disabled people's involvement and consultation in the SRB, and challenges the notion that SRB partnerships are inclusive to all sectors.
The Binary City
Authors: Sibley David
Published: September 2003

The characterisation of the Western city through binary classifications seems increasingly inappropriate, first, because cultural fusions produce 'thirdspaces' which can only be captured in a more complex spatial language and, secondly, because a thirdspace politics is needed to resist the oppressions associated with binary oppositions. In this paper, it is suggested that the thirdspace arguments promoted by Soja neglect a history of resistance and academic critiques of binaries loosely associated with anarchism. Drawing on the 'British school' of object relations in psychoanalysis, it is also argued that the failure to think beyond binaries and to realise a thirdspace politics may be connected with the construction of the 'Western self' in a culture which is suffuse with oppositions of desire and disgust.
Spatial Association and Heterogeneity Issues in Land Price Models
Authors: Paez Antonio , Uchida Takashi , Miyamoto Kazuaki
Published: September 2003

Urban planners frequently use regression analysis for the empirical estimation of land price models, which are used to investigate the spatial structure of a city or to calculate the implicit price of environmental characteristics. A concern with this kind of analysis is that often spatially associated or heterogeneous data are used, which leads to estimation pitfalls, most notably spatial autocorrelation and model structural instability over space. In this paper, we introduce a modelling methodology that combines a spatial autoregression with a switching regression to incorporate effectively both association and heterogeneity as part of the analysis. In addition, using Sendai City in north-eastern Japan as a case study, we use local statistics of spatial association to assist us in the exploration and definition of heterogeneous regimes. Finally, we show how some measures commonly used to counter spatial effects fail at times, thus highlighting the importance of a spatial modelling methodology such as the one presented here.
Home-ownership and Unemployment in the US
Authors: Green Richard K. , Hendershott Patric H.
Published: September 2003

In this paper, we scrutinise Oswald's evidence that home-ownership and unemployment are correlated across the US states. In order to abstract from state fixed-effects in levels, we analyse the cross-sectional variation in changes in home-ownership and unemployment rates between 1970 and 1990. After duplicating (nearly) Oswald's result, we illustrate the importance of weighting the state observations by the fraction of total US households in 1970 that resided in the respective states and of abstracting from the ageing of the population between 1970 and 1990: this causes Oswald's correlation to to disappear. Secondly, we estimate the relationship for six different age-classes and for household heads and total population. We find that the relationship is non-existent for both young households and old households, but exists for middle-aged households. Young households have accumulated little wealth and have had less time to become attached to the geographical area than middle-aged households and thus are more likely to respond to unemployment by relocating. Older households' employment cannot be greatly affected by home-ownership because their members are largely not in the labour force. Unemployment rates of household heads are affected less by tenure than those of the population as a whole.