bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient excess of
MYC
activity can elicit genomic instability and tumorigenesis
Authors: Felsher Dean W. , Bishop J. Michael
Published: July 2002

Overexpression of the
MYC
protooncogene has been implicated in the genesis of diverse human tumors. Tumorigenesis induced by
MYC
has been attributed to sustained effects on proliferation and differentiation. Here we report that
MYC
may also contribute to tumorigenesis by destabilizing the cellular genome. A transient excess of
MYC
activity increased tumorigenicity of Rat1A cells by at least 50-fold. The increase persisted for >30 days after the return of
MYC
activity to normal levels. The brief surfeit of
MYC
activity was accompanied by evidence of genomic instability, including karyotypic abnormalities, gene amplification, and hypersensitivity to DNA-damaging agents.
MYC
also induced genomic destabilization in normal human fibroblasts, although these cells did not become tumorigenic. Stimulation of Rat1A cells with
MYC
accelerated their passage through G
1
/S. Moreover,
MYC
could force normal human fibroblasts to transit G
1
and S after treatment with
N-
(phosphonoacetyl)-
l
-aspartate (PALA) at concentrations that normally lead to arrest in S phase by checkpoint mechanisms. Instead, the cells subsequently appeared to arrest in G
2
. We suggest that the accelerated passage through G
1
was mutagenic but that the effect of
MYC
permitted a checkpoint response only after G
2
had been reached. Thus,
MYC
may contribute to tumorigenesis through a dominant mutator effect.
Overexpression of thioredoxin in transgenic mice attenuates focal ischemic brain damage
Authors: Takagi Yasushi , Mitsui Akira , Nishiyama Akira , Nozaki Kazuhiko , Sono Hiroshi , Gon Yasuhiro , Hashimoto Nobuo , Yodoi Junji
Published: July 2002

Thioredoxin (TRX) plays important biological roles both in intra- and extracellular compartments, including in regulation of various intracellular molecules via thiol redox control. We produced TRX overexpressing mice and confirmed that there were no anatomical and physiological differences between wild-type (WT) mice and TRX transgenic (Tg) mice. In the present study we subjected mice to focal brain ischemia to shed light on the role of TRX in brain ischemic injury. At 24 hr after middle cerebral artery occlusion, infarct areas and volume were significantly smaller in Tg mice than in WT mice. Moreover neurological deficit was ameliorated in Tg mice compared with WT mice. Protein carbonyl content, a marker of cellular protein oxidation, in Tg mice showed less increase than did that of WT mice after the ischemic insult. Furthermore, c-fos expression in Tg mice was stronger than in WT mice 1 hr after ischemia. Our results suggest that transgene expression of TRX decreased ischemic neuronal injury and that TRX and the redox state modified by TRX play a crucial role in brain damage during stroke.
Scaling the universe: Gravitational lenses and the Hubble constant
Authors: Myers Steven T.
Published: July 2002

Gravitational lenses, besides being
interesting in their own right, have been demonstrated to be suitable
as “gravitational standard rulers” for the measurement of the
rate of expansion of the Universe (H
o
), as well as to
constrain the values of the cosmological parameters such as
Ω
o
and Λ
o
that control the evolution of the
volume of the Universe with cosmic time.
Estrogen receptor (ER) β, a modulator of ERα in the uterus
Authors: Weihua Zhang , Saji Shigehira , Mäkinen Sirpa , Cheng Guojun , Jensen Elwood V. , Warner Margaret , Gustafsson Jan-Åke
Published: July 2002

Many of the effects of estrogens on the uterus are mediated by ERα, the predominant ER in the mature organ. Because of the poor reproductive capacity of ERβ knockout (BERKO) female mice (small litter size, multiple-resorbed fetuses), the role of uterine ERβ was explored. In the immature uterus, ERα and ERβ are expressed at comparable levels in the epithelium and stroma, and 17β-estradiol (E2) treatment decreases ERβ in the stroma. The immature uterus of untreated BERKO mice exhibits elevated levels of progesterone receptor (PR) and the proliferation-associated protein, Ki-67. It also exhibits exaggerated responsiveness to E2, as indicated by enlargement of the lumen, increase in volume and protein content of uterine secretion, induction of the luminal epithelial secretory protein, complement C3, and its regulatory cytokine IL-1β, and induction of vascular endothelial growth factor and insulin-like growth factor 1 but not its receptor. As expected, E2increased PR in the stroma and decreased it in the luminal epithelium of wild-type mice. In the BERKO uterus, E2induced PR in the stroma but did not down-regulate it in the epithelium. Increased cell proliferation and exaggerated response to E2in BERKO suggest that ERβ plays a role in modulation of the effects of ERα and in addition (or as a consequence of this) has an antiproliferative function in the immature uterus.
Evolution of RNA editing in trypanosome mitochondria
Authors: Simpson Larry , Thiemann Otavio H. , Savill Nicholas J. , Alfonzo Juan D. , Maslov D. A.
Published: July 2002

Two different RNA editing systems have been described in the
kinetoplast-mitochondrion of trypanosomatid protists. The first
involves the precise insertion and deletion of U residues mostly within
the coding regions of maxicircle-encoded mRNAs to produce open reading
frames. This editing is mediated by short overlapping complementary
guide RNAs encoded in both the maxicircle and the minicircle molecules
and involves a series of enzymatic cleavage-ligation steps. The second
editing system is a C
34
to U
34
modification in
the anticodon of the imported tRNA
Trp
, thereby permitting
the decoding of the UGA stop codon as tryptophan. U-insertion editing
probably originated in an ancestor of the kinetoplastid lineage and
appears to have evolved in some cases by the replacement of the
original pan-edited cryptogene with a partially edited cDNA. The
driving force for the evolutionary fixation of these retroposition
events was postulated to be the stochastic loss of entire minicircle
sequence classes and their encoded guide RNAs upon segregation of the
single kinetoplast DNA network into daughter cells at cell division. A
large plasticity in the relative abundance of minicircle sequence
classes has been observed during cell culture in the laboratory.
Computer simulations provide theoretical evidence for this plasticity
if a random distribution and segregation model of minicircles is
assumed. The possible evolutionary relationship of the C to U and
U-insertion editing systems is discussed.
A pseudo zeta function and the distribution of primes
Authors: Chernoff Paul R.
Published: July 2002

The Riemann zeta function is given by:

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\begin{equation*}{\zeta}(s)={ \,\substack{ ^{{\infty}} \\ {\sum} \\ _{n=1} }\, }\hspace{.167em}1/n^{s}={\prod_{p\hspace{.167em}{\mathrm{prime}}}}\hspace{.167em} \left( 1-\frac{1}{p^{s}} \right) ^{-1}\hspace{.167em}{\mathrm{for\hspace{.167em}Re\hspace{.167em}}}s>1.\end{equation*}\end{document}

ζ(s) may be analytically continued to
the entire
s
-plane, except for a simple pole at
s =
0. Of great interest are the complex zeros of
ζ(
s
). The Riemann hypothesis states that the complex
zeros all have real part 1/2. According to the prime number theorem,

p
n
≈ n

log
n
, where

p
n

is the
n
th prime. Suppose
that

p
n

were exactly
n
log
n
. In other words, in the Euler
product above, replace the
n
th prime by
n
log
n
. In this way, we define a pseudo
zeta function C(
s
) for Re
s
> 1.
One can show that
C
(
s
) may be
analytically continued at least into the half-plane Re
s
> 0 except for an isolated singularity
(presumably a simple pole) at
s
= 0. It may be shown
that the pseudo zeta function
C
(
s
) has no
complex zeros whatsoever. This means that the complex zeros of the zeta
function are associated with the irregularity of the distribution of
the primes.
BRG-1 is required for RB-mediated cell cycle arrest
Authors: Strobeck Matthew W. , Knudsen Karen E. , Fribourg Anne F. , DeCristofaro Marc F. , Weissman Bernard E. , Imbalzano Anthony N. , Knudsen Erik S.
Published: July 2002

The antiproliferative action of the retinoblastoma tumor suppressor protein, RB, is disrupted in the majority of human cancers. Disruption of RB activity occurs through several disparate mechanisms, including viral oncoprotein binding, deregulated RB phosphorylation, and mutation of the RB gene. Here we report disruption of RB-signaling in tumor cells through loss of a critical cooperating factor. We have previously reported that C33A cells fail to undergo cell cycle inhibition in the presence of constitutively active RB (PSM-RB). To determine how C33A cells evade RB-mediated arrest, cell fusion experiments were performed with RB-sensitive cells. The resulting fusions were arrested by PSM-RB, indicating that C33A cells lack a factor required for RB-mediated cell cycle inhibition. C33A cells are deficient in BRG-1, a SWI/SNF family member known to stimulate RB activity. Consistent with BRG-1 deficiency underlying resistance to RB-mediated arrest, we identified two other BRG-1-deficient cell lines (SW13 and PANC-1) and demonstrate that these tumor lines are also resistant to cell cycle inhibition by PSM-RB and p16ink4a, which activates endogenous RB. In cell lines lacking BRG-1, we noted a profound defect in RB-mediated repression of the cyclin A promoter. This deficiency in RB-mediated transcriptional repression and cell cycle inhibition was rescued through ectopic coexpression of BRG-1. We also demonstrate that 3T3-derived cells, which inducibly express a dominant-negative BRG-1, arrest by PSM-RB and p16ink4a in the absence of dominant-negative BRG-1 expression; however, cell cycle arrest was abrogated on induction of dominant-negative BRG-1. These findings demonstrate that BRG-1 loss renders cells resistant to RB-mediated cell cycle progression, and that disruption of RB signaling through loss of cooperating factors occurs in cancer cells.
Compact stellarators with modular coils
Authors: Garabedian P. R.
Published: July 2002

Compact stellarator designs with modular coils and only two or three field periods are now available; these designs have both good stability and quasiaxial symmetry providing adequate transport for a magnetic fusion reactor. If the bootstrap current assumes theoretically predicted values a three field period configuration is optimal, but if that net current turns out to be lower, a device with two periods and just 12 modular coils might be better. There are also attractive designs with quasihelical symmetry and four or five periods whose properties depend less on the bootstrap current. Good performance requires that there be a satisfactory magnetic well in the vacuum field, which is a property lacking in a stellarator-tokamak hybrid that has been proposed for a proof of principle experiment. In this paper, we present an analysis of stability for these configurations that is based on a mountain pass theorem asserting that, if two solutions of the problem of magnetohydrodynamic equilibrium can be found, then there has to be an unstable solution. We compare results of our theory of equilibrium, stability, and transport with recently announced measurements from the large LHD experiment in Japan.
A supramolecular basis for CD45 tyrosine phosphatase regulation in sustained T cell activation
Authors: Johnson Kenneth G. , Bromley Shannon K. , Dustin Michael L. , Thomas Matthew L.
Published: July 2002

Transmembrane protein tyrosine phosphatases, such as CD45, can act as both positive and negative regulators of cellular signaling. CD45 positively modulates T cell receptor (TCR) signaling by constitutively priming p56lck through the dephosphorylation of the C-terminal negative regulatory phosphotyrosine site. However, CD45 can also exert negative effects on cellular processes, including events triggered by integrin-mediated adhesion. To better understand these opposing actions of tyrosine phosphatases, the subcellular compartmentalization of CD45 was imaged by using laser scanning confocal microscopy during functional TCR signaling of live T lymphocytes. On antigen engagement, CD45 was first excluded from the central region of the interface between the T cell and the antigen-presenting surface where CD45 would inhibit integrin activation. Subsequently, CD45 was recruited back to the center of the contact to an area adjacent to the site of sustained TCR engagement. Thus, CD45 is well positioned within a supramolecular assembly in the vicinity of the engaged TCR, where CD45 would be able to maintain src-kinase activity for the duration of TCR engagement.
Androgen-induced proliferative quiescence in prostate cancer cells: The role of AS3 as its mediator
Authors: Geck Peter , Maffini Maricel V. , Szelei Jozsef , Sonnenschein Carlos , Soto Ana M.
Published: July 2002

In the prostate gland of adult mammals, most epithelial cells are in a state of proliferative quiescence. Androgens regulate this effect by inducing cell cycle arrest in the G
0
/G
1
phase. Potential mediators of this androgen-induced proliferative shutoff were identified by means of subtracted cDNA libraries. The expression pattern of one of these sequences, AS3, strongly correlated with the expression of the androgen-induced proliferative shutoff both temporally and dosewise. The AS3 gene is located on chromosome 13 q12.3, in close proximity to the BRCA2 gene. The loss of chromosomal regions where AS3 alleles are located correlates with various human cancers, including prostate. The biological effect of AS3 was tested in two stable cell lines, one expressing sense and another expressing antisense AS3 constructs, both under tetracycline regulation. S9 cells were obtained by retroviral infection with virions containing a tetracycline-regulated sense AS3 construct. In these cells, sense AS3 was negatively regulated by tetracycline. Tetracycline withdrawal increased the expression of AS3 mRNA and protein. The expression of tetracycline-regulated AS3 resulted in inhibition of cell proliferation. A4 cells were obtained by retroviral infection with virions containing a tetracycline-regulated antisense AS3 construct. Vector-driven expression of antisense-AS3 blocked the induction of androgen-induced endogenous AS3 mRNA and blocked the inhibitory effect of androgens on cell proliferation. Tetracycline-regulated expression of the empty vector control had no effect on cell proliferation. These experiments strongly suggest that AS3 is a mediator of the androgen-induced proliferative shutoff.
Reactivation of encoding-related brain activity during memory retrieval
Authors: Nyberg Lars , Habib Reza , McIntosh Anthony R. , Tulving Endel
Published: July 2002

Neuronal models predict that retrieval of specific event
information reactivates brain regions that were active during encoding
of this information. Consistent with this prediction, this
positron-emission tomography study showed that remembering that visual
words had been paired with sounds at encoding activated some of the
auditory brain regions that were engaged during encoding. After
word-sound encoding, activation of auditory brain regions was also
observed during visual word recognition when there was no demand to
retrieve auditory information. Collectively, these observations suggest
that information about the auditory components of multisensory event
information is stored in auditory responsive cortex and reactivated at
retrieval, in keeping with classical ideas about
“redintegration,” that is, the power of part of an encoded
stimulus complex to evoke the whole experience.
A role for ubiquitin ligase recruitment in retrovirus release
Authors: Strack Bettina , Calistri Arianna , Accola Molly A. , Palù Giorgio , Göttlinger Heinrich G.
Published: July 2002

Retroviral Gag polyproteins have specific regions, commonly
referred to as late assembly (L) domains, which are required for the
efficient separation of assembled virions from the host cell. The L
domain of HIV-1 is in the C-terminal p6
gag
domain and
contains an essential P(T/S)AP core motif that is widely conserved
among lentiviruses. In contrast, the L domains of oncoretroviruses such
as Rous sarcoma virus (RSV) have a more N-terminal location and a PPxY
core motif. In the present study, we used chimeric Gag constructs to
probe for L domain activity, and observed that the unrelated L domains
of RSV and HIV-1 both induced the appearance of Gag-ubiquitin
conjugates in virus-like particles (VLP). Furthermore, a single-amino
acid substitution that abolished the activity of the RSV L domain in
VLP release also abrogated its ability to induce Gag ubiquitination.
Particularly robust Gag ubiquitination and enhancement of VLP release
were observed in the presence of the candidate L domain of Ebola virus,
which contains overlapping P(T/S)AP and PPxY motifs. The release
defect of a minimal Gag construct could also be corrected through the
attachment of a peptide that serves as a physiological docking site for
the ubiquitin ligase Nedd4. Furthermore, VLP formation by a full-length
Gag polyprotein was sensitive to lactacystin, which depletes the levels
of free ubiquitin through inhibition of the proteasome. Our findings
suggest that the engagement of the ubiquitin conjugation machinery by L
domains plays a crucial role in the release of a diverse group of
enveloped viruses.
Rational discovery of novel nuclear hormone receptor antagonists
Authors: Schapira Matthieu , Raaka Bruce M. , Samuels Herbert H. , Abagyan Ruben
Published: July 2002

Nuclear hormone receptors (NRs) are potential targets for therapeutic approaches to many clinical conditions, including cancer, diabetes, and neurological diseases. The crystal structure of the ligand binding domain of agonist-bound NRs enables the design of compounds with agonist activity. However, with the exception of the human estrogen receptor-α, the lack of antagonist-bound “inactive” receptor structures hinders the rational design of receptor antagonists. In this study, we present a strategy for designing such antagonists. We constructed a model of the inactive conformation of human retinoic acid receptor-α by using information derived from antagonist-bound estrogen receptor-α and applied a computer-based virtual screening algorithm to identify retinoic acid receptor antagonists. Thus, the currently available crystal structures of NRs may be used for the rational design of antagonists, which could lead to the development of novel drugs for a variety of diseases.
Expression patterns of
hairy
,
even-skipped
, and
runt
in the spider
Cupiennius salei
imply that these genes were segmentation genes in a basal arthropod
Authors: Damen Wim G. M. , Weller Mathias , Tautz Diethard
Published: July 2002

There is an ongoing discussion on whether segmentation in different phyla has a common origin sharing a common genetic program. However, before comparing segmentation between phyla, it is necessary to identify the ancestral condition within each phylum. Even within the arthropods it is not clear which parts of the genetic network leading to segmentation are conserved in all groups. In this paper, we analyze the expression of three segmentation genes of the pair-rule class in the spider
Cupiennius salei
. Spiders are representatives of the Chelicerata, a monophyletic basic arthropod group. We find that in spider embryos, the orthologues for the
Drosophila
primary pair-rule genes
hairy
,
even-skipped
, and
runt
are expressed in stripes in the growth zone, where the segments are forming, suggesting a role for these genes in chelicerate segmentation. These data imply that the involvement of
hairy
,
even-skipped
, and
runt
in arthropod segmentation is an ancestral character for arthropods and is not restricted to a particular group of insects.
Expression of membrane-associated carbonic anhydrase XIV on neurons and axons in mouse and human brain
Authors: Parkkila Seppo , Parkkila Anna-Kaisa , Rajaniemi Hannu , Shah Gul N. , Grubb Jeffrey H. , Waheed Abdul , Sly William S.
Published: July 2002

Although long suspected from histochemical evidence for carbonic
anhydrase (CA) activity on neurons and observations that CA inhibitors
enhance the extracellular alkaline shifts associated with synaptic
transmission, an extracellular CA in brain had not been identified. A
candidate for this CA was suggested by the recent discovery of membrane
CA (CA XIV) whose mRNA is expressed in mouse and human brain and in
several other tissues. For immunolocalization of CA XIV in mouse and
human brain, we developed two antibodies, one against a secretory form
of enzymatically active recombinant mouse CA XIV, and one against a
synthetic peptide corresponding to the 24 C-terminal amino acids in the
human enzyme. Immunostaining for CA XIV was found on neuronal membranes
and axons in both mouse and human brain. The highest expression was
seen on large neuronal bodies and axons in the anterolateral part of
pons and medulla oblongata. Other CA XIV-positive sites included the
hippocampus, corpus callosum, cerebellar white matter and peduncles,
pyramidal tract, and choroid plexus. Mouse brain also showed a positive
reaction in the molecular layer of the cerebral cortex and granular
cellular layer of the cerebellum. These observations make CA XIV a
likely candidate for the extracellular CA postulated to have an
important role in modulating excitatory synaptic transmission in brain.
Ancient Maya documents concerning the movements of Mars
Authors: Bricker Harvey M. , Aveni Anthony F. , Bricker Victoria R.
Published: July 2002

A large part of the pre-Columbian Maya book known as the Dresden
Codex is concerned with an exploration of commensurate relationships
among celestial cycles and their relationship to other, nonastronomical
cycles of cultural interest. As has long been known, pages 43b–45b of
the Codex are concerned with the synodic cycle of Mars. New work
reported here with another part of the Codex, a complex table on pages
69–74, reveals a concern on the part of the ancient Maya astronomers
with the sidereal motion of Mars as well as with its synodic cycle. Two
kinds of empiric sidereal intervals of Mars were used, a long one (702
days) that included a retrograde loop and a short one that did not. The
use of these intervals, which is indicated by the documents in the
Dresden Codex, permitted the tracking of Mars across the zodiac and the
relating of its movements to the terrestrial seasons and to the 260-day
sacred calendar. While Kepler solved the sidereal problem of Mars by
proposing an elliptical heliocentric orbit, anonymous but equally
ingenious Maya astronomers discovered a pair of time cycles that not
only accurately described the planet's motion, but also related it to
other cosmic and terrestrial concerns.
Chinese Dimensions of Parenting: Broadening Western Predictors and Outcomes
Authors: Stewart Sunita Mahtani , Rao Nirmala , Bond Michael H. , McBride‐Chang Catherine , Fielding Richard , Kennard Betsy D.
Published: July 2002

This study examined perceived parental styles and psychosocial adjustment in 97 Hong Kong Chinese late adolescent girls, using culturally sensitive measures of parenting (warmth, restrictive control, and attributes related to the Chinese philosophy of guan or “training”), and of adjustment. Parenting characteristics associated with guan showed coherence, correlated significantly with parental warmth, and predicted well‐being. Contrary to the suggestions of other investigators, restrictive control related negatively to self‐esteem and well‐being. Maternal control and paternal warmth emerged as important parent style variables in relating to adaptation, and exercized their effects on well‐being partly through the mediating agency of self‐esteem and relationship harmony. This preliminary study provides an empirical investigation of the impact exercized by a culturally specific dimension proposed for Chinese parenting, and highlights the importance of using culturally sensitive measures of adaptation.
Real Estate in Global Cities: Singapore and Hong Kong as Property States
Authors: Haila Anne
Published: July 2002

Land and buildings form a significant portion of the national wealth in most economies, but in Singapore and Hong Kong, two small city-states where land is scarce, real estate has an important role in the functioning of the whole economy. Transnational property and development companies are important players in Singapore and Hong Kong. They form an important part of the local stock market and have enjoyed considerable growth while providing substantial revenue for governments and wealth for individuals. Because of this important role, the paper redescribes Singapore and Hong Kong as property states, not rent-seeking economies as the term rent is usually used in discussing Asian capitalism. The importance of real estate, an immobile asset, is not only surprising in a global era defined in part by the mobility of capital, but also because in Singapore and Hong Kong land is publicly owned. The paper attempts to explain the anomaly by analysing the land allocation mechanisms in Singapore and Hong Kong. In spite of their similarities, real estate markets in Singapore and Hong Kong exhibit several differences, linked in turn to different policy options for their management.
Understanding Urban Development Processes: Integrating the Economic and the Social in Property Research
Authors: Guy Simon , Henneberry John
Published: July 2002

In their treatment of development, researchers in the property sector tend to adopt positivist methodologies which emphasise the application of rational decision-making techniques by utility-maximisers within a mainstream economics paradigm. While considerably increasing our understanding of the development process, such research offers a partial view of its subject from a particular perspective. Recently, alternative methodological and theoretical approaches have evolved which strive to understand the wider institutional context of the development process. The paper critically reflects on these institutionalist approaches in order to develop a research framework which blends economic and social analyses of property development processes. The paper draws upon (re)interpretations of the authors' recent research to address the following points. First, that the economic structuring of development is a product of and, in turn, affects social processes. This is illustrated by a consideration of the price mechanism in the property market. Secondly, that social structures and processes are as important as their economic equivalents in 'explaining' property development. This is addressed by a discussion of the ways in which recent shifts in the social organisation of the property sector are reframing the strategies of development actors, leading to new structures of property provision and use. The paper concludes by arguing for the need to develop an understanding of property development processes which combines a sensitivity to the economic and social framing of development strategies with a fine-grain treatment of the locally contingent social responses of property actors.
Measuring the Economic Benefits of the Ozone Pollution Control Policy in Seoul: Results of a Contingent Valuation Survey
Authors: Yoo Seung-Hoon , Chae Kyung-Suk
Published: July 2002

Controlling ozone pollution has become an increasingly important policy issue in developing countries such as Korea, as well as in developed countries. One response to this concern is to assess the benefits that would ensue from a proposed ozone pollution control policy. This paper applies a contingent valuation method to obtain at least a preliminary evaluation of the benefits of a policy, using a specific case study of Seoul, Korea. Respondents overall accepted the contingent market and were willing to contribute a significant amount, on average, per household. This willingness varies according to individual characteristics. The study also discusses the importance of including the ozone pollution control problem in a cost-benefit analysis and presents the policy implications of the results.
Can Commutes Be Used to Test the Spatial Mismatch Hypothesis?
Authors: DeRango Kelly
Published: July 2002

This paper uses a simple spatial model of urban employment to demonstrate that the relationship between spatial mismatch and commuting times is indeterminate if employment probabilities decline as the distance from job site to residence increases. Specifically, if employment probabilities decline faster (slower) than a threshold rate, then spatial mismatch will decrease (increase) the commuting times of central-city minorities. Thus, commuting-based tests of the spatial mismatch hypothesis are not just biased but mis-specified because spatial mismatch is theoretically consistent with both the null and alternative hypotheses. Evidence that this concern is empirically important is taken from the `contradictory' findings of recent studies that use commutes to test the spatial mismatch hypothesis.
Identifying Neighbourhood Effects on Social Exclusion
Authors: Buck Nick
Published: July 2002

Interest in the influence of the neighbourhood on the life-chances of individuals has been increasing. However, methodological problems in identifying causal models of these influences suggest the need for caution in such inference. This paper uses data from the British Household Panel Study linked to local area characteristics to explore how far there is evidence that outcomes associated with social exclusion (non-monetary poverty measures, measures of labour market engagement, entry into jobs and flows in and out of poverty) may be associated with neighbourhood characteristics. The paper finds significant associations even when controlling for a substantial range of individual characteristics. There is also limited evidence of a non-linear effect with worse outcomes in the very worst areas for at least one measure. Analysis of the spatial scale of associations suggests mixed results, with stronger associations at the most local scales for some but not all outcomes.
Intermetropolitan Variation in the Labour Force Participation Rates of White and Black Men in the United States
Authors: Ellis Mark , Odland John
Published: July 2002

We decompose the variance in black and white male labour force participation rates across US metropolitan areas in 1990 into three effects: that due to variation in labour force participation within labour force categories across metropolitan areas (local labour market effects); that due to variation in the distribution of those categories across metropolitan areas (labour force structure effects); and that due to the covariation between these two effects. Variation in labour force participation rates within labour force categories (local labour market effects) accounts for 56 per cent of the variance in labour force participation rates across metropolitan areas for white men but over 75 per cent for black men. Variation in the frequency of membership in each labour force category is a relatively unimportant factor for both groups. The covariance between labour force effects and local effects is negligible for black men but accounts for 25 per cent of the intermetropolitan variance in white male participation rates. This covariance is a measure of how well adjusted the labour force characteristics of metropolitan areas are to local economic conditions; our results indicate that this adjustment is greater for white men than black men. We also use this decomposition to identify the causes of variation in the difference between black and white labour force participation rates. Black-white differences in response to local labour market effects conditions generate most of this variance. These different local labour market effects are greatest among young single men with less than a high school education.
Understanding the Movement of Goods, Not People: Issues, Evidence and Potential
Authors: Woudsma Clarence
Published: July 2002

The movement of goods or freight occurs in every urban area. However, such movements have not received the same level of attention as that given to the movements of people. We do not understand the effects of several massive changes affecting urban freight movements. This paper presents a comparative review of planning studies of the movement of goods in order to assess our current understanding and to provide a context for a research agenda on the movement of urban goods. The studies reviewed provide basic data such as time of day activity, trip and vehicle characteristics. However, they do not provide an understanding of the key relationships that underlie the movement of goods, including those related to land use/transport interaction. Basic research into an integrated modelling effort for urban goods movement (UGM) is needed to address issues associated with congestion and air quality that affect most major urban centres.
Multicultural Policy within Local Government in Australia
Authors: Dunn Kevin , Thompson Susan , Hanna Bronwyn , Murphy Peter , Burnley Ian
Published: July 2002

This paper examines results from an Australia-wide survey of multicultural policies at the level of local government. Multicultural policies have the potential to advance a local 'politics of difference', recasting governance, such that citizenship is expanded. Multicultural policies are described in terms of access and equity programmes, community relations policies and symbolic representations of cultural diversity and inclusive citizenship. The questionnaire survey of managers within local government revealed a broad array of good practices. However, there remained significant service gaps for residents of non-English-speaking backgrounds as well as a general reluctance to tackle instances of serious intercommunal tension. There was also some hesitancy to embrace the notion of a diverse local citizenry.
Neighbourhood Effects in Large and Small Neighbourhoods
Authors: Overman Henry G.
Published: July 2002

This paper uses data from a sample of Australian teenagers to test for neighbourhood effects on school dropout rates. The data allow us to test for neighbourhood effects at two different spatial scales. We find that the educational composition of the larger neighbourhood can influence the dropout rate. We argue that this is most likely to reflect the structure of local labour market demand. We also find that the low socioeconomic status of the immediate neighbourhood has an adverse impact on dropout rate. This suggests that government policy may need to consider the socioeconomic composition of quite small geographical areas if it considers interfering in the market to create greater income-mixing within neighbourhoods.
The Top-level Global Research System, 1997-99: Centres, Networks and Nodality. An Analysis Based on Bibliometric Indicators
Authors: Wichmann Matthiessen Christian , Winkel Schwarz Annette , Find Søren
Published: July 2002

The importance of the knowledge-base in regional and urban competition is generally recognised, although causal relations between urban and regional economic growth and knowledge level are far from clear. This paper presents the first analysis of the strength, interrelations and nodality of the global research centres. The data are records in the Science Catation Index 1997-99 of papers produced by authors from the 40 largest `greater' urban regions of the world as measured by research output. The network of research co-operation depends on nationality, distance and other factors. The top-level nodes in the co-operation network of the world are London, Geneve-Lausanne and the San Francisco Bay Area. In absolute number of co-authored papers, Los Angeles, Boston and New York constitute a second level and, when observed links are related to expected links, the second level combines Amsterdam-Hague-Rotterdam-Utrecht, Paris, Basel-Mulhouse-Freiburg and Copenhagen-Lund. As expected, the networks of citation are, by contrast, very independent of distance, but not of nationality. The primary categories of research centres for the total number of citings presented are San Diego, Seattle, Boston, New York and the San Francisco Bay Area. When we turn to the international data-set, it is Mannheim-Heidelberg, Geneve-Lausanne, Basel-Mulhouse-Freiburg and Cambridge which are in the lead.
The Impacts of Borrowing Constraints on Home-ownership in Australia
Authors: Bourassa Steven C.
Published: July 2002

The analysis reported in this article incorporates direct measures of borrowing constraints into an otherwise standard model of the home-ownership decision in Australia. Borrowing constraints take into account mortgage underwriting criteria, household incomes and wealth, and the household's optimal level of consumption of housing services. Models containing borrowing constraint measures are estimated for households with heads ages 25-34, the age-group that is most likely to be moving into home-ownership. Consistent with previous findings in the US and Canada, borrowing constraints are significant determinants of the probability of ownership. Including borrowing constraints in the tenure-choice model results in a reduction in the independent impacts of household income and the relative costs of owning and renting, implying that in the standard model these variables are at least in part proxies for borrowing constraints. As wealth is the binding constraint for most constrained renters, the article concludes that government programmes to encourage first-time buyers should focus on reducing deposit requirements.
The Provision of Urban Infrastructure in Iran: An Empirical Evaluation
Authors: Mehdi Azizi Mohammad
Published: July 2002

Servicing new residential areas has been a major problem in the context of rapid urban expansion. While public expenditure has traditionally played a major role in infrastructure financing, finding and establishing new methods of financing have recently been an important issue. Iran has found the user-pays system to be an efficient financing method. The first part of this paper analyses the nature, significance and process of urban infrastructure provision. The second part looks at the new policy of urban land development in Iran during 1985-90. It goes on to examine the effectiveness of the user-pays system in Iran and the impacts of various factors on the system such as city size and the scales of projects.
Naturalising Choices and Neutralising Voices? Discourse on Urban Development in Two Cities
Authors: ter Borg Elisabeth , Dijkink Gertjan
Published: July 2002

Post-modern conceptions of social projects stress the closed nature of the communications involved (discourse). Philosophers in this tradition have presented discourse procedures and power relations as forces constraining the possibilities of expression and change. Two aspects have been selected in this article to examine the appropriateness of the discourse perspective with regard to urban development policy: discontinuity and compulsiveness. An analysis of shifting policy aims in two cities affirms the presence of several features assigned to discourses. Both cities represent different positions on a continuum between more and less disciplined (closed) discourse. Critical voices, however, are never completely absent; they only operate at different distances from the inner political circle.
Mortgage Finance and Housing Provision in Ireland, 1970-90
Authors: Murphy Laurence
Published: July 2002

Mortgage institutions actively shape the character of home-ownership in advanced capitalist economies. An understanding of the forces promoting institutional change and the nature of these changes provides insights into the developing structure of home ownership. Using a 'structures of housing provision' framework, this paper examines the dynamics of the Irish housing market over the period 1970-90. Combining data on macro-level trends in housing finance with information gathered from interviews with senior building society personnel, it is argued that the restructuring of the mortgage market in the 1980s has significantly altered the set of social relations that exist between agents located in the housing market and that these changes are having negative impacts on the owner-occupied sector.
Living Together Apart: Residential Segregation in Mixed Arab-Jewish Cities in Israel
Authors: Falah Ghazi
Published: July 2002

This paper examines features of residential segregation in five mixed Arab-Jewish cities in Israel; the role of ideology and state politics among the charter group—i.e. the Jewish population—is considered to be a dominant factor in this social process. Utilising available Israeli census data supplemented by the author's own field survey, the study indicates that all five cities have experienced a continuous trend of high indices of segregation and hypersegregation. The spatial manifestation of this trend is a classic display of sectoral (but not concentric) patterns of residency. Concomitantly, the scope of both social and economic interactions between the two communities sharing the same urban space remains underdeveloped. The city has effectively provided a sense of local identity: both groups live in and are part of the same place, yet this space is not a locus for genuine integration. A situation of neighbours without neighbourly relations marks the residential reality of Israeli mixed cities.
Ten Propositions in UK Housing Macroeconomics: An Overview of the 1980s and Early 1990s
Authors: Meen Geoffrey
Published: July 2002

During the last ten years, macroeconomists have increasingly come to realise that there are important interactions between housing and the wider economy. In some cases, this realisation has come too late to avoid the severe oscillations in the economy that have characterised the period since the mid-1980s. This paper uses a macroeconometric model, specifically designed to capture the interactions, in order to reflect on the experience of the 1980s and early 1990s and to draw theoretical, empirical and policy conclusions in terms of ten propositions.
Do Girls Have a Higher School Drop-out Rate than Boys? A Hazard Rate Analysis of Evidence from a Third World City
Authors: Akhtar Sajjad
Published: July 2002

This paper estimates gender-specific conditional probabilities of drop-out from the schools in Karachi, a large metropolitan city of Pakistan. The analysis is based on the socio-economic and demographic data of family members extracted from a large sample survey of households in the city. Studies in urban Pakistan have found a lower participation rate (unconditional probability) for girls than boys. In contrast, our results indicate that the probability of drop-out of females is lower than boys at institutionally established 'exit' points in the schooling system of Karachi.
The Position of Former Council Homes in the Housing Market
Authors: Forrest Ray , Gordon David , Murie Alan
Published: July 2002

The Right to Buy for council tenants has now been in operation for 14 years. In that time around 1.5m public-sector dwellings in England have transferred to the owner-occupied sector. Most discussion of this process has focused on the impact on the public sector. This paper examines the contribution of council house sales to the recent growth of home ownership and price relationships between former council homes and other dwellings in the market. The paper draws on a major national study of the resale of former council homes which included a survey of over 3000 dwellings which had been resold by the original sitting tenant purchasers.
Area-based Poverty and Resident Empowerment
Authors: Power Anne
Published: July 2002

The gap between the poorest people in Britain and the average has grown significantly since the late 1970s. People in the lowest income groups are increasingly overrepresented in council housing. Most council housing is built in large, separate, single-purpose estates. Therefore area-based poverty has grown. In these areas, housing, income and social factors interact to create steep decline. As conditions became more extreme, local authorities and central government developed special experiments in localisation which had a measurable impact on conditions, involving residents and attracting management effort towards local problems. Estates with the least favourable conditions and most polarised populations received more intensive estates services and often improved through concentrated, long-term support. While residents were involved in and influenced these developments, in only a few cases did they actually take responsibility for or control over services to their area. Where they did this successfully it had the most far-reaching impact on the process of renewal. Localisation, coupled with strong outside support and links to the city, appears to offer a way out of spiralling conditions and growing alienation. Evidence that this change is happening in Britain is borne out by the European experience of estate decline and estate rescue. If localisation of housing services, along with policing, social services, health and education was extended to all large, separate, low-income estates, it would maximise the impact of collective provision on vulnerable communities.
General Linear Gravity Models for the Impact of Casualty Unit Closures
Authors: Congdon Peter
Published: July 2002

This paper considers general linear modelling approaches to assessing the impact of restructuring Accident and Emergency services, and in particular the anticipated changes in demand for emergency admission to those hospitals with casualty units remaining following the closure of one or more casualty units at other hospitals. The particular formulation adopted here stresses the relevance of supply weighting and accessibility in gravity modelling applications where the independence from irrelevant alternative axiom is unlikely to pertain. Also discussed is the generation of 'what if' scenarios according to changes in demand for Accident & Emergency services, and according to the assumed mechanism governing the distribution of changing demand by hospital. A case study of localities and hospitals in north east London is presented.
Negotiating Development Charges in Ontario: Average Cost versus Marginal Cost Pricing of Services
Authors: Tomalty Ray , Skaburskis Andrejs
Published: July 2002

This article attempts to determine how the interplay of stakeholders in a larger economic and political context influences the design of development charge regimes in particular jurisdictions. As a vehicle for this exploration, the authors pose the question: Why do so many municipalities adopt average cost approaches to calculating development charges when it is widely assumed that a marginal cost approach is superior from an infrastructure and land-use efficiency perspective? The question is addressed through a case study method, which focuses on the creation of development charge regimes in Ontario, Canada, and in particular on eight 'focus' municipalities within the Greater Toronto Area. The article begins by presenting the 'pragmatic' explanations for adopting an average cost approach offered by finance officials and consultants. These explanations present the average cost method as the outcome of the deliberate application of basic principles of efficiency, equity, administrative simplicity and public acceptability. We proceed by showing that such explanations are incomplete or incoherent in important ways and turn to more 'critical' explanations, which require an understanding of developer-municipal conflict over the principles involved in the design of development charges. This leads us to an account of the emergence of development charges in Ontario and the evolving debate between municipalities and developers over who should pay for the infrastructure needed to support growth. This account reveals that there has been a gradual shift in municipal infrastructure financing practices from a marginal cost or 'site-specific' approach, favoured by developers, to an average cost or 'municipality-wide' approach, favoured by municipalities. Associated with this trend has been an evolution from negotiated charges to formulaic charges. In the conclusions, a number of factors underlying this evolution are identified.