bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of Ras in lymphocytes: get a GRP
Authors: Stone J.C.
Published: October 2006

RasGRPs (guanine nucleotide releasing proteins) are a family of four GEFs (guanine nucleotide-exchange factors) (Ras GEFs) that positively regulate Ras and related small GTPases. RasGRP1 possesses a catalytic region consisting of a REM (Ras exchange motif) and a CDC25 (cell division cycle 25) domain. RasGRP1 also possesses a DAG (diacylglycerol)-binding C1 domain and a pair of EF hands that bind calcium. RasGRP1 is selectively expressed in lymphocytes as well as in some cells of the brain, kidney and skin. Functional analysis supports the hypothesis that RasGRP1 serves to couple TCR (T-cell receptor) stimulation and phospholipase C activation with Ras signalling. In B-cells, both RasGRP1 and RasGRP3 play a similar role downstream of the B-cell receptor. RasGRP2 acts on the Ras-related protein Rap and functions in platelet adhesion. RasGRP4 is expressed in mast cells and certain myeloid leukaemia cells. Membrane DAG regulates RasGRPs directly by recruitment to cellular membranes, as well as indirectly by protein kinase C-mediated phosphorylation. The properties of RasGRPs provide a novel view of Ras regulation in lymphocytes and explain several earlier observations. Many experimental results obtained with DAG analogues could be reviewed in light of these findings.
Gating of two-pore domain K+ channels by extracellular pH
Authors: Niemeyer M.I. , González-Nilo F.D. , Zúñiga L. , González W. , Cid L.P. , Sepúlveda F.V.
Published: October 2006

Potassium channels have a conserved selectivity filter that is important in determining which ions are conducted and at what rate. Although K+ channels of different conductance characteristics are known, they differ more widely in the way their opening and closing, the gating, is governed. TASK and TALK subfamily proteins are two-pore region KCNK K+ channels gated open by extracellular pH. We discuss the mechanism for this gating in terms of electrostatic effects on the pore changing the occupancy and open probability of the channels in a way reminiscent of C-type inactivation gating at the selectivity filter. Essential to this proposed mechanism is the replacement of two highly conserved aspartate residues at the pore mouth by asparagine or histidine residues in the TALK and TASK channels.
Plasma membrane IP3 receptors
Authors: Taylor C.W. , Dellis O.
Published: October 2006

IP3Rs (inositol 1,4,5-trisphosphate receptors) are expressed in the membranes of non-mitochondrial organelles in most animal cells, but their presence and role within the plasma membrane are unclear. Whole-cell patch–clamp recording from DT40 cells expressing native or mutated IP3Rs has established that each cell expresses just two or three functional IP3Rs in its plasma membrane. Only approx. 50% of the Ca2+ entry evoked by stimulation of the B-cell receptor is mediated by store-operated Ca2+ entry, the remainder appears to be carried by the IP3Rs expressed in the plasma membrane. Ca2+ entering the cell via just two large-conductance IP3Rs is likely to have very different functional consequences from the comparable amount of Ca2+ that enters through the several thousand low-conductance store-operated channels.
Kainate receptor-interacting proteins and membrane trafficking
Authors: Coussen F. , Mulle C.
Published: October 2006

Kainate receptors are composed of several subunits and splice variants, but the relevance of this diversity is still not well understood. The subunits and splice variants show great divergence in their C-terminal cytoplasmic tail region, which has been identified as a region of interaction with a number of protein partners. Differential trafficking of kainate receptors to neuronal compartments is likely to rely on interactions with distinct subsets of protein partners. This review summarizes our knowledge of the regulation of trafficking of kainate receptors and focuses on the identification and characterization of functions of interacting partners.
Molecular mechanisms for regulation of AMPAR trafficking by PICK1
Authors: Hanley J.G.
Published: October 2006

AMPA (α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) receptor trafficking is a fundamental mechanism for regulating synaptic strength, and hence may underlie cellular processes involved in learning and memory. PICK1 (protein that interacts with protein C-kinase) has recently emerged as a key regulator of AMPAR (AMPA receptor) traffic, and the precise molecular mechanisms of PICK1's action are just beginning to be unravelled. In this review, I summarize recent findings that describe some important molecular characteristics of PICK1 with respect to AMPAR cell biology.
Blinking fluorophores: what do they tell us about protein dynamics?
Authors: Bagshaw C.R. , Cherny D.
Published: October 2006

The ability to detect emission from a single fluorophore presents a powerful tool to probe the dynamic properties of protein molecules during their interactions with ligands. Here, different classes of experiments are reviewed and a distinction is drawn between experiments that monitor signals from a large number of proteins, one molecule at a time, from those that follow a single protein molecule over many individual cycles. The latter approach is potentially capable of resolving dynamic heterogeneity, such as that displayed by enzymes that fluctuate between high and low activity states. Other factors that need to be considered are the origin of the fluctuations in the emission signal and the extent to which this represents the properties of the protein under investigation, as opposed to the probe itself. Most fluorophores show fluctuations in their emission rates, termed flickering, blinking or intermittency, which may occur on a similar time-scale as the event under investigation.
Inhibitors of the catalytic domain of mitochondrial ATP synthase
Authors: Gledhill J.R. , Walker J.E.
Published: October 2006

An understanding of the mechanism of ATP synthase requires an explanation of how inhibitors act. The catalytic F1-ATPase domain of the enzyme has been studied extensively by X-ray crystallography in a variety of inhibited states. Four independent inhibitory sites have been identified by high-resolution structural studies. They are the catalytic site, and the binding sites for the antibiotics aurovertin and efrapeptin and for the natural inhibitor protein, IF1.
Novel time-of-flight spectrometer for the analysis of positron annihilation induced Auger electrons
Authors: Hugenschmidt Christoph , Legl Stefan
Published: October 2006

Positron annihilation induced Auger-electron spectroscopy (PAES) has several advantages over conventional Auger-electron spectroscopy such as extremely high surface sensitivity and outstanding signal-to-noise ratio at the Auger-transition energy. In order to benefit from these prominent features a low-energy positron beam of high intensity is required for surface sensitive PAES studies. In addition, an electron energy analyzer is required, which efficiently detects the Auger electrons with acceptable energy resolution. For this reason a novel time-of-flight (TOF) spectrometer has been developed at the intense positron source NEPOMUC that allows PAES studies within short measurement time. This TOF-PAES setup combines a trochoidal filter and a flight tube in a Faraday cage in order to achieve an improved energy resolution of about 1eV at high electron energies up to E≈1000eV. The electron flight time is the time between the annihilation radiation at the sample and when the electron hits a microchannel plate detector at the end of the flight tube.
Forward-backward semiclassical initial value series representation of quantum correlation functions
Authors: Martin-Fierro Eva , Pollak Eli
Published: October 2006

The forward-backward (FB) approximation as applied to semiclassical initial value representations (SCIVR’s) has enabled the practical application of the SCIVR methodology to systems with many degrees of freedom. However, to date a systematic representation of the exact quantum dynamics in terms of the FB-SCIVR has proven elusive. In this paper, we provide a new derivation of a forward-backward phase space SCIVR expression (FBPS-SCIVR) derived previously by Thompson and Makri [Phys. Rev. E 59, R4729 (1999)]. This enables us to represent quantum correlation functions exactly in terms of a series whose leading order term is the FBPS-SCIVR expression. Numerical examples for systems with over 50degrees of freedom are presented for the spin boson problem. Comparison of the FBPS-SCIVR with the numerically exact results of Wang [J. Chem. Phys. 113, 9948 (2000)] obtained using a multiconfigurational time dependent method shows that the leading order FBPS-SCIVR term already provides an excellent approximation.
Periodic boundary condition induced breakdown of the equipartition principle and other kinetic effects of finite sample size in classical hard-sphere molecular dynamics simulation
Authors: Shirts Randall B. , Burt Scott R. , Johnson Aaron M.
Published: October 2006

We examine consequences of the non-Boltzmann nature of probability distributions for one-particle kinetic energy, momentum, and velocity for finite systems of classical hard spheres with constant total energy and nonidentical masses. By comparing two cases, reflecting walls (NVE or microcanonical ensemble) and periodic boundaries (NVEPG or molecular dynamics ensemble), we describe three consequences of the center-of-mass constraint in periodic boundary conditions: the equipartition theorem no longer holds for unequal masses, the ratio of the average relative velocity to the average velocity is increased by a factor of [N∕(N−1)]1∕2, and the ratio of average collision energy to average kinetic energy is increased by a factor of N∕(N−1). Simulations in one, two, and three dimensions confirm the analytic results for arbitrary dimension.
An analytic model for the optical properties of gold
Authors: Etchegoin P. G. , Le Ru E. C. , Meyer M.
Published: October 2006

A simple analytic model for the optical properties of gold is proposed. The model includes a minimum set of parameters necessary to represent the complex dielectric function of gold in the visible and near-uv regions. Explicit values for the parameters to reproduce the Johnson and Christy data [Phys. Rev. B 6, 4370 (1972)] on the optical properties of gold are provided.
Long nanotube dielectric properties used as sensors of large molecules: A semicontinuum approach
Authors: Picaud F. , Langlet R. , Girardet C.
Published: October 2006

A semicontinuum approach on the basis of an effective polarizability tensor per length and radius units is used to describe the dielectric response of a long single wall nanotube to the adsorption of an extended molecule. Changes in the permittivity ratio of the nanotube+molecule over the nanotube alone, which are directly connected to frequency shifts of the nanotube in a resonator configuration due to the presence of the molecule, provide a test of sensitivity of the system. The behavior of this ratio is analyzed for linear and circular geometries of the molecule, as a function of the tube characteristics (length and radius) and of the molecular size and polarizability distribution. Extension to three dimensional systems with a large set of polarizable centers is discussed in terms of self-polarization of the centers and morphology of the surface of the sensed system.
Flow around spheres by dissipative particle dynamics
Authors: Chen Shuo , Phan-Thien Nhan , Khoo Boo Cheong , Fan Xi Jun
Published: October 2006

The dissipative particle dynamics (DPD) method is used to study the flow behavior past a sphere. The sphere is represented by frozen DPD particles while the surrounding fluids are modeled by simple DPD particles (representing a Newtonian fluid). For the surface of the sphere, the conventional model without special treatment and the model with specular reflection boundary condition proposed by Revenga et al. [Comput. Phys. Commun. 121–122, 309 (1999)] are compared. Various computational domains, in which the sphere is held stationary at the center, are investigated to gage the effects of periodic conditions and walls for Reynolds number (Re)=0.5 and 50. Two types of flow conditions, uniform flow and shear flow are considered, respectively, to study the drag force and torque acting on the stationary sphere. It is found that the calculated drag force imposed on the sphere based on the model with specular reflection is slightly lower than the conventional model without special treatment. With the conventional model the drag force acting on the sphere is in better agreement with experimental correlation obtained by Brown and Lawler [J. Environ. Eng. 129, 222 (2003)] for the case of larger radius up to Re of about 5. The computed torque also approaches the analytical Stokes value when Re<1. For a force-free and torque-free sphere, its motion in the flow is captured by solving the translational and rotational equations of motion. The effects of different DPD parameters (a, γ, and σ) on the drag force and torque are studied. It shows that the dissipative coefficient (γ) mainly affects the drag force and torque, while random and conservative coefficient have little influence on them. Furthermore the settling of a single sphere in square tube is investigated, in which the wall effect is considered. Good agreement is found with the experiments of Miyamura et al. [Int. J. Multiphase Flow 7, 31 (1981)] and lattice-Boltzmann simulation results of Aidun et al. [J. Fluid Mech. 373, 287 (1998)].
Probing the electronic properties of dichromium oxide clusters Cr2On− (n=1–7) using photoelectron spectroscopy
Authors: Zhai Hua-Jin , Wang Lai-Sheng
Published: October 2006

In an effort to elucidate the variation of the electronic structure as a function of oxidation and composition, we investigated an extensive series of dichromium oxide clusters, Cr2On− (n=1–7), using photoelectron spectroscopy (PES). Well-resolved PES spectra were obtained at several photon energies. While low photon energy spectra yielded much better spectral resolution, high photon energy data allowed both Cr 3d- and O 2p-derived detachment features to be observed. The overall spectral evolution of Cr2On− exhibits a behavior of sequential oxidation with increasing oxygen content, where low binding energy Cr 3d-based spectral features diminish in numbers and the spectra shift towards higher binding energies as a result of charge transfer from Cr to O. Evidence was obtained for the population of low-lying isomers for Cr2O2−, Cr2O3−, and Cr2O6−. The current data are compared with previous studies and with related studies on W2On− and Mo2On−.
Launching a particle on a ring: b2u→ke2g ionization of C6F6
Authors: Das Aloke , Poliakoff E. D. , Lucchese R. R. , Bozek John D.
Published: October 2006

Evidence is presented demonstrating that an electron launched into the continuum is trapped in an unprecedented quasibound state, namely, one that extends through the backbone of the six-member carbon ring of C6F6. The mode specificity of the vibrational sensitivity to the electron trapping provides an experimental signature for this phenomenon, while adiabatic static model-exchange scattering calculations are used to map the wave function, which corroborate the interpretation.
Quasi-phase-matched Čerenkov second-harmonic generation in a hexagonally poled LiTaO3 waveguide
Authors: Zhang Y. , Qi Z. , Wang W. , Zhu S. N.
Published: October 2006

The authors reported a type of second-harmonic generation in a hexagonally poled LiTaO3 waveguide. The emerged second-harmonic waves exhibited a hexagonal pattern when projected on a screen behind the waveguide. This frequency conversion process was realized by guided-to-radiated mode interaction. Phase matching for this process was automatically achieved by a quasi-phase-matched Čerenkov configuration.
Optical determination of the electron effective mass of strain compensated In0.4Ga0.6As0.995N0.005∕GaAs single quantum well
Authors: Xu LiFang , Patel D. , Menoni C. S. , Yeh J. Y. , Mawst L. J. , Tansu Nelson
Published: October 2006

A detailed line shape analysis of the temperature dependent photoluminescence spectra of In0.4Ga0.6As1−yNy∕GaAs quantum well (QW) (y=0,0.005) is carried out and the relative contribution of free excitons and free carriers to the radiative recombination at different temperature is quantitatively assessed. The analysis extracts the binding energy of the e1-hh1 ground-state exciton which equals 9.72±1.24 and 17.5±0.9meV for InGaAs and InGaAsN (N=0.5%) single QW sample, respectively. By using a fractional dimension exciton binding energy model, an electron effective mass of me*=(0.11±0.015)m0 is determined for the highly strained dilute nitride single QW.
Model for the thickness dependence of electron concentration in InN films
Authors: Cimalla V. , Lebedev V. , Morales F. M. , Goldhahn R. , Ambacher O.
Published: October 2006

A model for the influence of different contributions to the high electron concentration in dependence on the film thickness of state-of-the-art InN layers grown by molecular-beam epitaxy is proposed. Surface accumulation has a crucial influence for InN layers <300nm and superimposes the background concentration. For air-exposed InN, it can be assigned to a surface near doping by oxygen. For InN layers in the micron range the density of dislocations is the major doping mechanism. Finally, point defects such as vacancies and impurities have minor influence and would dominate the free electron concentration only for InN >10μm.
Polymeric cantilever-based biosensors with integrated readout
Authors: Johansson Alicia , Blagoi Gabriela , Boisen Anja
Published: October 2006

The authors present an SU-8 cantilever chip with integrated piezoresistors for detection of surface stress changes due to adsorption of biomolecules on the cantilever surface. Mercaptohexanol is used as a model biomolecule to study molecular interactions with Au-coated SU-8 cantilevers and surface stress changes of about 0.1N∕m are observed. The measurements indicate that the SU-8 surface is inert to mercaptohexanol molecules, which enables the use of a bare SU-8 cantilever as a reference. Moreover, the sensitivity of the cantilevers to pH changes is presented. The results demonstrate that SU-8 cantilevers are a promising alternative to Si-based cantilevers.
Common features of nanostructure formation induced by the surface undulation on the Stranski-Krastanow systems
Authors: Chiu C.-H. , Huang Z.
Published: October 2006

The nanostructure formation effected by the surface undulation on the Stranski-Krastanow (SK) systems during the annealing process is investigated by simulating the morphological evolution of the systems driven by surface diffusion. The results reveal three common features in the formation process. First, the essence of the nanostructure formation is the transformation of the film material above the wetting layer into faceted islands. Second, the wetting layer thickness is given by the first critical thickness for the SK transition. Third, the width of the nanostructures measured at the average film height is close to a constant during the formation process.
Accurately evaluating Young’s modulus of polymers through nanoindentations: A phenomenological correction factor to the Oliver and Pharr procedure
Authors: Tranchida Davide , Piccarolo Stefano , Loos Joachim , Alexeev Alexander
Published: October 2006

The Oliver and Pharr [J. Mater. Res. 7, 1564 (1992)] procedure is a widely used tool to analyze nanoindentation force curves obtained on metals or ceramics. Its application to polymers is, however, difficult, as Young’s moduli are commonly overestimated mainly because of viscoelastic effects and pileup. However, polymers spanning a large range of morphologies have been used in this work to introduce a phenomenological correction factor. It depends on indenter geometry: sets of calibration indentations have to be performed on some polymers with known elastic moduli to characterize each indenter.
Photon-number state on-demand source by cavity parametric downconversion
Authors: Hayat Alex , Orenstein Meir
Published: October 2006

The authors propose a realizable scheme for an arbitrary photon-number state on-demand source based on parametric downconversion in a doubly resonant photonic cavity. The signal-wavelength resonance serves as storage for signal photons and the idler-wavelength resonance generates time separation between exiting idler photons, enabling photon-number-resolving detection. The counting of idler photons indicates the desired signal photon-number state, which can be released from the cavity on demand. They analyze the statistics of photon-number states generation and estimate the maximal repetition rates. Performance of the monolithic cavity for signal-storage and idler time spacing is limited, however, by external devices, namely, the long recovery time of existing single-photon detectors.
Voltage monitoring hydrostatic pressure method for measuring the force sensitivity of piezoelectric films
Authors: Ezhilvalavan S. , Xu Guolin , Loh Jeremy , Samper Victor D. , Ying Jackie Y.
Published: October 2006

A simple nondestructive method for measuring the force sensitivity of freestanding piezoelectric films is presented. The principle used is the direct piezoelectric effect, and the force sensitivity of the film is calculated by measuring the charge generated across the film and the magnitude of the applied pressure. A hydrostatic pressure is generated by pressurizing the oil in the chamber using a voice coil actuator. This method is capable of measuring the force sensitivity in the range of millinewton with a simple sample preparation in the form of a parallel plate capacitor structure. This straightforward measurement also results in improved electrical characterization of the piezoelectric capacitor and is suitable for the low-cost testing of microelectromechanical systems.
Electro-optically modulated localized surface plasmon resonance biosensors with gold nanoparticles
Authors: Wang Tzyy-Jiann , Lin Wen-Shao
Published: October 2006

An integrated-optic biosensor based on electro-optically modulated localized surface plasmon resonance (LSPR) is demonstrated. This biosensor utilizes the electro-optic effect to modulate the wave vector of incident lightwave used to excite localized surface plasmons. Electro-optically modulated LSPR results in the analyte-dependent variation of output intensity with the applied voltage. The linear regression slope of this relation is used to determine the analyte concentration. On the sensing region of LSPR biosensor, human serum albumin is self-assembled on gold nanoparticles in order to sense the beta-blocker concentration. The use of the presented biosensor has the features of no intensity drift problem, no absorption diversity problem in different sample media, and noise reduction by linear regression analysis.
Nitrogenase Fe protein: A molybdate/homocitrate insertase
Authors: Hu Yilin , Corbett Mary C. , Fay Aaron W. , Webber Jerome A. , Hodgson Keith O. , Hedman Britt , Ribbe Markus W.
Published: October 2006

The Fe protein is indispensable for nitrogenase catalysis and biosynthesis. However, its function in iron-molybdenum cofactor (FeMoco) biosynthesis has not been clearly defined. Here we show that the Fe protein can act as a Mo/homocitrate insertase that mobilizes Mo/homocitrate for the maturation of FeMoco precursor on NifEN. Further, we establish that Mo/homocitrate mobilization by the Fe protein likely involves hydrolysis of MgATP and protein–protein interaction between the Fe protein and NifEN. Our findings not only clarify the role of the Fe protein in FeMoco assembly and assign another function to this multitask enzyme but also provide useful insights into a mechanism of metal trafficking required for the assembly of complex metalloproteins such as nitrogenase.
A cryptochrome/photolyase class of enzymes with single-stranded DNA-specific photolyase activity
Authors: Selby Christopher P. , Sancar Aziz
Published: October 2006

Photolyases and cryptochrome blue-light photoreceptors are evolutionarily related flavoproteins that perform distinct functions. Photolyases repair UV-damaged DNA in many species from bacteria to plants and animals. Cryptochromes regulate growth and development in plants and the circadian clock in animals. Recently, a new branch of the photolyase/cryptochrome family was identified. Members of this branch exhibited no or trace levels of DNA repair activity
in vivo
and
in vitro
and, therefore, were considered to be cryptochromes, and they were named cryptochrome-DASH. Here, we show that Cry-DASH proteins from bacterial, plant, and animal sources actually are photolyases with high degree of specificity for cyclobutane pyrimidine dimers in ssDNA.
On Growth Poles
Authors: Lasuen J.R.
Published: October 2006

Perroux argued that economic space as an abstract field of forces leads to the notion of a vector of economic forces, and hence to the concept of growth poles.

His further view that economic development necessarily requires spatial polarisation is an inaccurate and damaging limitation of this concept. Whilst the early stages of economic development must generate growth points due to a lack of entrepreneurship outside these centres, development in advanced countries is becoming less polarised. This is caused by the increasingly diversified structure of business which results in an extensive spatial spread of innovations and economic development. It follows that developing countries can accelerate their growth by creating diversified corporate structures which diminish the exigencies of a polarised strategy.
Revealed Preferences for Neighbourhood Characteristics
Authors: Leven Charles L. , Mark Jonathan H.
Published: October 2006

The research reported here analyses the relative influence of a variety of neighbourhood characteristics, not by the more common means of aggregate comparative analysis, but by examination of major influences revealed by the observed market behaviour of an interviewed sample of actual movers in St Louis, Missouri. The most significant result was the failure of changing percentage non-white population to account for movers' revealed preferences, despite both study areas having had rapid increases in that percentage over the study period. Median family income was shown to be the strongest single influence, and several other results run contrary to traditional economic location models.
The Move into Council Housing: The Effect on Quit Rates
Authors: Engleman S.R.
Published: October 2006

The move into council housing can affect family welfare not only in terms of their housing conditions but in other spheres as well. In this paper we examined the influence of changed journey to work costs arising out of a move into council housing on the propensity to quit current employment. Using separate models for men and women regression analysis is employed to estimate the effects of changed journey to work times on a sample of men and women who moved into Glasgow council housing. A control group is utilised and the effects of various personal characteristics and other factors are also taken into account. Increased travel time resulted in an increased quit rate for the men in the sample whereas for the women no relationship between quits and increased journey to work time was observed.
An Investigation into the Estimation and Reliability of Urban Shopping Models
Authors: Turner R. , Cole H.S.D.
Published: October 2006

This paper evaluates the reliability of variants of five urban shopping models : Central Place theory, the Intervening Opportunities model, Gravity model, the Entropy model, and the Building Research Establishment (BRE) model. For each model variant parameters are estimated against data for four towns in the United Kingdom: Coventry, Derby, Watford and Telford, using alternative procedures for testing significance of the calibration. The models are then used to forecast hypothetical changes in local shopping environments, including dynamic effects, such as the progressive decline of local centres. On the basis of the results, some general conclusions are drawn as to the relative performance of the models and the factors determining their reliability in different forecasting situations.
Determinants of Population Density Gradient in Tel Aviv Metropolitan Area
Authors: Alperovich Gershon
Published: October 2006

Urban population density gradients have been traditionally estimated from cross-sectional data. The estimates obtained show a flattening of the gradients through time. Few works have attempted to empirically investigate the determinants of the parameters of the function. In this paper we have specified and estimated a simple model of density gradient which uses pooled cross-sectional and time-series data. The results show that income, size of metropolitan area and a time variable explain well the flattening through time of the density gradient in Tel Aviv metropolitan area.
The Contribution of Crime to Urban Decline
Authors: Katzman Martin T.
Published: October 2006

The fact that crime is higher in the larger urban centers and in the central cities of metropolitan areas suggests that crime has contributed to suburbanisation. Previous studies have been unable to extricate crime from other causes of suburbanisation and central city decline. The present study of residential mobility isolates the effect of property crime from other neighborhood characteristics, such as accessibility to workplace and social composition. In Dallas it is found that the repelling effects of crime for potential movers is greater for families with children than without and for more affluent families, white and black.
The Impact of Soviet Housing Policy on Housing Conditions in Soviet Cities: The Uneven Push from Moscow
Authors: Nechemias Carol
Published: October 2006

This paper describes the causes of variation in housing conditions between Soviet cities, where the state owns over 78 per cent of the housing stock. It also describes the impact of a massive effort to overcome the acute housing shortage, focussing on variations in flows of benefits to different communities.
A Study of the Economic Impact of Industrial Relocation: the Case of Seoul
Authors: Kwon Won-Yong
Published: October 2006

Korea has experienced rapid simultaneous urbanisation and industrialisation leading to a high level of concentration of population and economic activity in Seoul. The structure of the economy of Seoul is described. The need for policies to achieve decentralisation is examined and the implications of such policies are listed. The paper identifies those sectors which are likely to be most suitable for relocation away from the capital. Finally, by using input-output tabulations and multipliers, the paper is able to measure the probable total impact of such decentralisation and the relative costs and benefits of such a process.
Why Women Work Closer to Home
Authors: Fanning Madden Janice
Published: October 2006

This paper analyzes the extent to which differences in labor force status, in household composition, and in household roles account for sex differences in workplace-residence separation. Modelling work trip length as the outcome of the choice of household residential and individual job locations, equilibrium work trip length is estimated empirically as a function of labor market, housing, and household characteristics for male and female employees in seven different household categories. Data from the 1976 Panel Survey of Income Dynamics are used. The study concludes that while sex differences in job tenure, work hours, and wages are in themselves sufficient to fully account for observed sex differences in workplace-residence separation, sex differences in household 'roles' (i.e., responses to spouses' characteristics) are of even greater importance in influencing women to work 'closer to home'.
Public Housing and Slums: Cure or Cause?
Authors: Vitaliano Donald F.
Published: October 2006

This paper tests the hypothesis that an increase in the supply of public housing causes a substantially offsetting decline in the quantity supplied of competing private units. The statistical results offer little by way of confirmation of this view.

A comparative statics model of the rental housing market is presented from which estimating equations suitable for regression analysis are derived. Data from the US Census are used to estimate the effect of public housing on the private rental sector in 33 cities in New York State. The empirical evidence suggests a 5 to 9 per cent induced decline in private market rents per one per cent increase in the proportion of public units in the total housing stock. No meaningful evidence of private market vacancies, demolitions or dilapidation offsetting to the public units was found.
Welfare Analysis of Pollution Control With Spatial Alternatives
Authors: Thomas Vinod
Published: October 2006

This paper deals with the welfare losses resulting from emission control policies which do not take into account differences in control costs among firms and in benefits across regions. In contrast, an optimal policy considers these differences, and on their basis, requires differential controls among regions, presumably encouraging spatial adaptation of production. Drawing on an empirical analysis of welfare benefits and welfare costs of controlling particulate emissions from the iron and steel industry in two different areas, substantial gains are noted from an optimal policy over uniform and other regulations when damages vary significantly across regions.
Public Policy and the Effects of Crime in the Inner City: A British Example
Authors: Smith Susan J.
Published: October 2006

In Britain as in North America, the effects of crime extend beyond the limited experiences of victims. Yet, policies seeking to allay fear are rarely those expedient to discourage offenders. The debilitating consequences of crime for the quality of inner city life might therefore be alleviated by the initiatives of urban managers other than those formally assigned to crime control and law enforcement.
The Space Cost Curve and Variable Transport Costs: a General Production Function Case
Authors: Shieh Yeung-nan
Published: October 2006

This paper attempts to incorporate a production function with input substitution into the Smith model and to re-examine the basic properties and the shape of space cost curve. It has shown the space cost curve will be (i) concave from below in the distance plane, when the transport rate is constant or decreasing with distance; (ii) linear, convex or concave from below in the distance plane, when the transport rate is increasing with distance. This result is quite different from Smith's, Richardson's and Mai's.
Plant Size and Urban Growth
Authors: Kipnis Baruch A.
Published: October 2006

The issue of the impact of plant size on urban growth is evaluated, using survey data employed in constructing an input-output table for Joinville, an isolated urban manufacturing city in Brazil. The study indicates that small and medium size plants are more favourable for urban growth than are larger plants. This is found to be true for backward and forward flows of goods and services, and for the labour force structure. These findings, along with those revealed in other studies referring to plant size, suggest a revision in the way that manufacturing industry, as an initiator of the urban growth process, is applied.
Functional Typologies of Metropolitan Areas: An Examination of Their Usefulness
Authors: Clark Roger D. , Roche John P.
Published: October 2006

Although relatively simple dichotomies of American cities, such as the Sunbelt/Snowbelt and the largecity/small-city distinctions, have been used to explain and predict other facets of urban life, more elaborate typologies, such as those produced by Duncan and others (1960) and by Nelson (1955), have remained wallflowers of urban research. Curiously attractive, they have nonetheless found little favor in explanatory studies. We have found two of these typologies, those of Duncan et al. and Nelson, to be surprisingly useful in accounting for major changes in the American urban system during the 1970s.
Parameters of the Retail Trade Model: A Utility Based Interpretation
Authors: Grigg Trevor
Published: October 2006

Recently, attention has been directed at the existence and stability of the supply-side equilibria implied by the traditional retail trade model. Some interest has also been shown in the dynamic behaviour of retail suppliers by postulating various supply adjustment mechanisms in response to demand-supply imbalances. This research has demonstrated the important role played by the model parameters in determining the modelled behaviour of the retail trade market. However, until we have a firm conceptual basis for these parameters, and for the model itself, we may only be succeeding in increasing our understanding of the mathematical properties of the model without contributing significantly to an improved understanding of the interaction of retail demand and supply. The aim of this paper is to provide a probabilistic interpretation of the model and its parameters using random utility theory.
Proportion Analysis on Cell Data: Distortions Due to Variations in Cell Sizes
Authors: Cuthbert J.R.
Published: October 2006

'Proportion' analysis is a technique for comparing the relative incidence of concentrated deprivation between regions. It is applied when population or household data is available down to the level of small areal units or cells. The technique involves calculating the proportion of households in each cell possessing a given attribute: identifying those cells with extreme proportions: and then drawing inferences based on the incidence of these selected cells. This technique is shown to be sensitive to bias in the presence of variations in size of the basic cells. A general formula is derived for calculating the extent of the bias, under simplifying assumptions. Tables are given, illustrating the extent of the bias in particular cases.
Spatial Differentials in Residential Displacement
Authors: Lee Barrett A. , Hodge David C.
Published: October 2006

Because existing research treats residential displacement as a consequence of housing market conditions associated with the urban core, the incidence of displacement is thought to be greater in: (1) metropolitan areas than nonmetropolitan areas, (2) the 'urban heartland' than other regions of the country, (3) central cities than suburbs, and (4) older, inner-city neighborhoods than younger, peripheral ones. Data from the US Annual Housing Survey are analyzed and case studies of individual cities are reviewed to test these four spatial hypotheses. While the strength of the evidence favoring the hypotheses depends in part upon the type of displacement rate employed, spatial contrasts in displacement generally appear to be less marked than the literature suggests. We attribute the lack of convincing support for the hypotheses to housing market pressures operating at the national level that generate involuntary mobility across all geographical sectors of the population.
An Examination of Selected Consequences of Revitalization in Six US Cities
Authors: DeGiovanni Frank F.
Published: October 2006

This paper examines four selected consequences of private market revitalization in 12 neighborhoods in six US cities. The analysis reveals that the physical quality of properties has been improved significantly, property assessments have increased substantially, and the investment in the properties by newcomers to the neighborhoods has encouraged original owners to improve their properties in one-third of the neighborhoods studied. However, the increase in assessed values generally has lagged far behind increases in the market value of the properties. Reinvestment also appears to have generated negative consequences. Many of the renters living in the neighborhoods prior to the start of reinvestment, many of whom had a low socioeconomic status, may have been displaced. In addition, the assessed value of properties owned by persons living in the neighborhoods prior to revitalization and not improved during revitalization increased as a result of the changes occurring in the neighborhoods. The percentage increase in the assessed value of these properties was not significantly less than the increase for properties improved by newcomers.
Allocation Systems and Housing Choice
Authors: Clapham David , Kintrea Keith
Published: October 2006

This article examines the major approach to the study of allocation in British public housing, i.e. the institutional approach. It argues that the approach is unsatisfactory because it ignores factors which originate from outside of the institutional context and also the interaction between the individual household and the institution. These drawbacks can be remedied by focusing on the choices facing households, by using household choice models similar to those used in studying the movement of households in the private market. It is only by using this approach that the major problems of allocation in British public housing will be identified.
Housing Careers, Life Cycle and Residential Mobility: Implications for the Housing Market
Authors: Kendig Hal L.
Published: October 2006

The concept of a housing career provides a useful way of integrating the residential mobility and filtering literatures in understanding the operation of the housing market. Using data from a survey in Adelaide, the paper examines these careers in terms of moves to and from both rental accommodation and home ownership. It shows how the progression of households through the stock is influenced by the circumstances that prompt moves, economic resources, and stage in the family life cycle. The results suggest that acceleration and postponement of advancement along housing careers provide the principal mechanisms by which household demand adjusts to available housing supply over the short term.
P* Segregation Indices: What Can They Tell Us about Housing Segregation in 1980?
Authors: Farley John E.
Published: October 2006

An alternative measure of segregation, the P* index, is explained. This measure is computed separately for each racial/ethnic group and, in a diadic situation, indicates each group's potential for neighborhood contact with the other. The usefulness of this index, as well as the different information it provides from that provided by other indices, is discussed. P* indices are computed for blacks and whites for the St Louis metropolitan area in 1970 and 1980. The results indicate that neither group experienced a sizable increase in residential contact with the other between 1970 and 1980. The significance of this finding in a context of increasing black suburbanization is discassed.
City Size and Income Distributions: The Canadian Experience
Authors: Soroka Lewis A.
Published: October 2006

Recent US studies generally conclude that city size contributes to greater intra-urban income inequality, while higher average income levels contribute to equality. We argue that Canadian cities and the Canadian urban system are in some ways different from those in the US, and that American results may not therefore be transferable to Canada. This is confirmed by our testing with 1971 Census data; we find that city size does not affect urban income distributions in Canada, although higher levels of income do add to equality, as in the US. We conclude that American findings may be due to the particularities of US cities, and that long term growth of Canadian cities, while perhaps of some concern for other reasons, does not appear to threaten existing levels of income equality.
The Demand for Housing, Household Headship Rates, and Household Formation: An International Analysis
Authors: Smith Lawrence B. , Rosen Kenneth T. , Markandya Anil , Ullmo Pierre-Antoine
Published: October 2006

This study investigates the influence of availability and affordability of housing on demographic changes through an international analysis of the relationship between age specific headship rates and housing availability and affordability. The researchers describe the basic trends in household formation and headship rates in Canada, France, Great Britain and the United States, investigate the economic determinants of age specific household headship rates in the four countries, and discuss the implications for future housing analysis. It was found that the considerable increase in household headship rate during the recent postwar period has been facilitated in these four countries by the increasing real affordability of housing. In addition, there was a clear relationship between the household age category and the responsiveness to economic variables.
Comparability and Incomparability in Housing Programmes in Wales; A Spatial Analysis for 1981
Authors: Prentice Richard
Published: October 2006

In this paper Census data are investigated as possible explanations of recent housing investment in Wales. Public sector investment is found to relate poorly to need, but private sector investment in new construction is found to be responsive to surrogate measures of demand. Housing investment is found to be substantially independent by sector.
An Empirical Look at Housing Rehabilitation as a Spatial Process
Authors: McConney Mary E.
Published: October 2006

This paper addresses the question of whether the repair behavior of owner occupants depends on the housing upkeep of neighboring owners. The policy issue is whether spatial targeting of rehabilitation loans and grants to low income owners in specific areas of a city is effective in leveraging private funds of adjacent residents for housing repairs. This paper presents four case studies of low income residential areas that have been targeted for community development aid. Data collected for the Community Development Strategies Evaluation Project suggests that the additional amount each owner spends for every thousand dollars his/her neighbors spend, although measurable, is very small.
Housing Policy as a Planning Tool
Authors: van Vliet Willem
Published: October 2006

In Israel, housing policy has traditionally been aimed at broader objectives beyond the supply of adequate shelter. Using data from a nationwide survey of young couples (N = 2,591), this study examines the relationship between the government's major housing-assistance program and two principal national goals: a spatially balanced and socially integrated population. The housing policy's basic tenet, the provision of extra benefits to those settling in new towns, appears to promote dispersal but to hinder integration. This finding parallels a divergence between standard measures of housing quality and resident's own evaluations. The conclusion discusses the importance of considering a plurality of goals and both objective and subjective indicators in policy making.
Planned Economic Development and Loglinearity in the Rank-Size Distribution of Urban Systems: The Soviet Experience
Authors: Mirucki Jean
Published: October 2006

In this paper, the city rank-size hypothesis is tested for the urban system of the USSR and the Republic of Ukraine using (1) census data for 1897, 1926, 1939, 1959, 1970 and 1979, (2) subgrouping each census year in 3 categories: largest cities (rank 1-5), middle-sized cities (rank 6-50) and smallest cities (rank higher than 50) in addition to the whole sample. Following the interpretation of the previous results, the relative changes in the ratios of the city distribution slope values from both systems are then observed and analysed for each of the specified group of cities.
Area Policy Impacts: A Multiplier Analysis of GEAR
Authors: Nairn A.G.M. , Swales J.K.
Published: October 2006

This paper attempts to quantify the employment and income effects of the Glasgow Eastern Area Renewal (GEAR) programme on its target area. This is done using an augmented Keynesian multiplier approach. The multiplier model is adjusted to take into account the particular characteristics of the injection and the fact that the target area is small and well-integrated within a large conurbation. The results are disaggregated so that the impact of each element of the programme is separately-identified, and the overall results are subject to sensitivity analysis. Although the estimated increases in employment and income are large in absolute terms, they are small relative to the decline that immediately preceded the introduction of the GEAR programme.