bluuebunny/crossref_metadata_2025_split huggingface dataset:
Have Falling Tariffs and Transportation Costs Raised US Wage Inequality?
Authors: Haskel Jonathan E. , Slaughter Matthew J. 
Published: September 2003

AbstractTo gauge the effect of international trade on the rising US skill premium, the paper analyzes the sector bias of price changes induced by changes in US tariffs and transportation costs. It is found that, in both the 1970s and 1980s, cuts in tariffs and transportation cost levels were concentrated in unskilled‐intensive sectors. Despite this suggestive evidence, the authors estimate that price changes induced by tariffs or transportation costs mandated a rise in inequality that was mostly statistically insignificant. Thus, they do not find strong evidence that falling tariffs and transport costs, working through price changes, mandated rises in inequality.
Relation‐based versus Rule‐based Governance: an Explanation of the East Asian Miracle and Asian Crisis
Authors: Li John Shuhe 
Published: September 2003

AbstractThe paper aims to establish a theory of relation‐based governance to explain both the “East Asian miracle” and the Asian crisis. The author first defines “relation” and “relation‐based governance” in terms of information and enforcement, and then analyzes the nature and dynamics of relation‐based governance, comparing its benefits and costs with that of “rule‐based governance” in terms of observability/verifiability, commitment, and transaction costs. The theory is applied to examine a particular relation‐based governance system—the Japanese model—to explain both the East Asian miracle and the Asian crisis. The framework provides foundations for studies of East Asian catching‐up and economic development in general.
Mundell Revisited: a Simple Approach to the Costs and Benefits of a Single Currency Area
Authors: Ching Stephen , Devereux Michael B. 
Published: September 2003

AbstractThe paper evaluates the costs and benefits of a single currency area within a unified framework. Conventionally, it is argued that a single currency area carries a welfare loss owing to the sacrifice of exchange rate adjustment in the presence of country‐specific shocks. But in 1973 Mundell argued that a single currency area offers risk‐sharing benefits when capital markets are limited in their ability to facilitate consumption insurance. The authors construct a simple model and compare a system of independent national currencies to a single currency area. The presence of country‐specific shocks may either reduce or enhance the benefits of a single currency area, depending on the importance of exchange rate adjustment relative to risk‐sharing. In a simple quantitative analysis, we find that either regime may dominate, although the utility differences between the two regimes are very small.
Factor Market Oligopsony and the Production Possibility Frontier
Authors: Devadoss Stephen , Song Wongun 
Published: September 2003

AbstractThe authors consider a model with two final goods, one intermediate good, and two primary factors. One final good and the intermediate good are produced using primary factors, labor and capital. The other final good is produced using labor and the intermediate input. Producers of the second final good exert oligopsonistic market power on the intermediate input, which captures real world phenomena prevalent in the food processing and other manufacturing industries. If the capital/labor ratio in one final‐good sector is in between those of the intermediate‐input sector and the combined intermediate‐input and the other final‐product sectors, and if the oligopsony power is sufficiently large, the model generates results that are not adherent to the standard two‐sector Heckscher–Ohlin model. Results that deviate from the H–O model include the relationships between factor prices and commodity prices, the price–output effect, tangency between the price line and the PPF, and the curvature of the PPF.
Calculating Power for the Comparison of Dependentκ-Coefficients
Authors: Lin Hung-Mo , Williamson John M. , Lipsitz Stuart R. 
Published: September 2003

SummaryIn the psychosocial and medical sciences, some studies are designed to assess the agreement between different raters and/or different instruments. Often the same sample will be used to compare the agreement between two or more assessment methods for simplicity and to take advantage of the positive correlation of the ratings. Although sample size calculations have become an important element in the design of research projects, such methods for agreement studies are scarce. We adapt the generalized estimating equations approach for modelling dependent κ-statistics to estimate the sample size that is required for dependent agreement studies. We calculate the power based on a Wald test for the equality of two dependent κ-statistics. The Wald test statistic has a non-central χ2-distribution with non-centrality parameter that can be estimated with minimal assumptions. The method proposed is useful for agreement studies with two raters and two instruments, and is easily extendable to multiple raters and multiple instruments. Furthermore, the method proposed allows for rater bias. Power calculations for binary ratings under various scenarios are presented. Analyses of two biomedical studies are used for illustration.
A Class of Models for Aggregated Traffic Volume Time Series
Authors: Brockwell A. E. , Chan N. H. , Lee P. K. 
Published: September 2003

Summary
The development of time series models for traffic volume data constitutes an important step in constructing automated tools for the management of computing infrastructure resources. We analyse two traffic volume time series: one is the volume of hard disc activity, aggregated into half-hour periods, measured on a workstation, and the other is the volume of Internet requests made to a workstation. Both of these time series exhibit features that are typical of network traffic data, namely strong seasonal components and highly non-Gaussian distributions. For these time series, a particular class of non-linear state space models is proposed, and practical techniques for model fitting and forecasting are demonstrated.
A Novel Bootstrap Procedure for Assessing the Relationship between Class Size and Achievement
Authors: Carpenter James R. , Goldstein Harvey , Rasbash Jon 
Published: September 2003

SummaryThere is on-going concern about the relationship between class size and achievement for children in their first years of schooling. The Institute of Education’s class size project was set up to address this issue and began recruiting in the autumn of 1996. However, because of the non-normality of achievement measures, especially in mathematics, the results have hitherto been presented by using transformed achievement measures. This makes the interpretation difficult for non-statisticians. Ideally, the data would be modelled on the original scale and a bootstrap procedure used to ensure that inferences are robust to non-normality. However, the data are multilevel. In the paper we therefore propose a nonparametric residual bootstrap procedure that is suitable for multilevel models, show that it is consistent and present a simulation study which demonstrates its potential to yield substantial reductions in the difference between nominal and actual confidence interval coverage, compared with a parametric bootstrap, when the underlying distribution of the data is non-normal. We then apply our approach to estimate the relationship between class size and achievement for children in their reception year, after adjusting for other possible determinants.
Tracing Studies and Analysis of the Effect of Loss to Follow-Up on Mortality Estimation from Patient Registry Data
Authors: Farewell Vernon T. , Lawless Jerald F. , Gladman Dafna D. , Urowitz Murray B. 
Published: September 2003

SummaryBefore patient registries are used for studies of the long-term mortality that is associated with chronic medical conditions, the potential bias resulting from patients who become lost to follow-up must be investigated. A study design, used for a systemic lupus erythematosus patient registry, is described. The design involves tracing patients who are defined as ‘lost to follow-up’ according to specific criteria. This provides supplementary information on the mortality experience of patients who are lost to (regular) follow-up. Some methods of analysis are described, based on comparing the mortality experience of patients when under regular follow-up with the experience of patients after they are deemed to be lost to follow-up. The effect of loss to follow-up, death reporting and visits to the clinic on estimation procedures is illustrated and recommendations are made for patient registries which are to be used in mortality studies.
Modelling Forces of Infection by Using Monotone Local Polynomials
Authors: Shkedy Ziv , Aerts Marc , Molenberghs Geert , Beutels Philippe , Van Damme Pierre 
Published: September 2003

SummaryOn the basis of serological data from prevalence studies of rubella, mumps and hepatitis A, the paper describes a flexible local maximum likelihood method for the estimation of the rate at which susceptible individuals acquire infection at different ages. In contrast with parametric models that have been used before in the literature, the local polynomial likelihood method allows this age-dependent force of infection to be modelled without making any assumptions about the parametric structure. Moreover, this method allows for simultaneous nonparametric estimation of age-specific incidence and prevalence. Unconstrained models may lead to negative estimates for the force of infection at certain ages. To overcome this problem and to guarantee maximal flexibility, the local smoother can be constrained to be monotone. It turns out that different parametric and nonparametric estimates of the force of infection can exhibit considerably different qualitative features like location and the number of maxima, emphasizing the importance of a well-chosen flexible statistical model.
Modelling Heterogeneous Space–Time Occurrences of Earthquakes and its Residual Analysis
Authors: Ogata Yosihiko , Katsura Koichi , Tanemura Masaharu 
Published: September 2003

SummaryEarthquake intensities are modelled as a function of previous activity whose specific form is based on established empirical laws in seismology, but whose parameter values can vary from place to place. This model is used for characterizing regional features of seismic activities in and around Japan, and also for exploring regions where the actual seismicity rate systematically deviates from that of the modelled rate.
Final‐Offer Arbitration: A New Zealand Variation
Authors: Mcandrew Ian 
Published: September 2003

This journal was the first to publicize the concept of final‐offer arbitration (FOA), so it is appropriate that it also publish a brief description of a unique form of FOA used to settle police compensation disputes in New Zealand. As with many forms of FOA, this approach requires mediation before arbitration. What makes it unique is that the arbitrator is present during the mediation and can provide feedback to the parties on “trial balloon” final offers. Another unique feature is that the dispute‐settlement system was designed by the parties themselves, within an enabling legislative framework, and has been molded by them over the past decade.This article describes this different form of FOA and the parties’ experiences with it through several rounds of salary negotiations during the 1990s. Being based on reports by the participants, it is subject to the normal biases of parties asked to evaluate their own handiwork.
In Situ Activation of the Quorum-Sensing Transcription Factor TraR by Cognate and Noncognate Acyl-Homoserine Lactone Ligands: Kinetics and Consequences
Authors: Luo Zhao-Qing , Su Shengchang , Farrand Stephen K. 
Published: September 2003

ABSTRACTConjugal transfer of Ti plasmids ofAgrobacterium tumefaciensis controlled by a quorum-sensing system composed of the transcriptional activator TraR and its acyl-homoserine lactone quormoneN-(3-oxo-octanoyl)-l-homoserine lactone (3-oxo-C8-HSL). The population density dependence of quorum-sensing systems can often be circumvented by addition of the quormone to cultures at low cell numbers. However, the quorum-dependent activation of Ti plasmid conjugal transfer exhibited a lag of almost 8 h when the quormone was added to donor cells at low population densities (Piper and Farrand, J. Bacteriol. 182:1080-1088, 2000). As measured by activation of a TraR-dependenttraG::lacZreporter fusion, TraR in cells exposed to the cognate signal for 5 min showed detectable activity, while exposure for 15 min resulted in full activity. Thus, the lag in activation is not due to some intrinsic property of TraR. Cells exposed to the agonistic analogN-(3-oxo-hexanoyl)-l-homoserine lactone (3-oxo-C6-HSL) exhibited similar induction kinetics. However, activation of the reporter in cells exposed to the poorly effective alkanoyl acyl-HSLN-hexanoyl-l-homoserine lactone (C6-HSL) required the continued presence of the signal. As measured by an in vivo repressor assay, TraR activated by 3-oxo-C6-HSL or by 3-oxo-C8-HSL remained active for as long as 8 h after removal of exogenous signal. However, TraR activated by the alkanoyl quormone C6-HSL rapidly lost activity following removal of the signal. In quormone retention assays, which measure signal binding by TraR, cells grown with either of the two 3-oxo-acyl-HSL quormones retained the ligand after washing, while cells grown with C6-HSL lost the alkanoyl-HSL concomitant with the rapid loss of TraR activity. We conclude that TraR rapidly binds its quormone and that, once bound, the cognate signal and its close homologs are tightly retained. Moreover, in the absence of other regulatory factors, activated TraR remains functional after removal of the signal. On the other hand, poorly active signals are not tightly bound, and their removal by washing leads to rapid loss of TraR activity.
Secretion of LamB-LacZ by the Signal Recognition Particle Pathway of
Escherichia coli
Authors: Bowers Christina Wilson , Lau Fion , Silhavy Thomas J. 
Published: September 2003

ABSTRACT

LamB-LacZ fusion proteins have classically been used in studies of the general secretion pathway of
Escherichia coli
. Here we describe how increasing signal sequence hydrophobicity routes LamB-LacZ Hyb42-1 to the signal recognition particle (SRP) pathway. Secretion of this hydrophobic fusion variant (H*LamB-LacZ) was reduced in the absence of fully functional Ffh and Ffs, and the translocator jamming caused by Hyb42-1 was prevented by efficient delivery of the fusion to the periplasm. Finally, we found that in the absence of the ribosome-associated chaperone, trigger factor (Tig), LamB-LacZ localized to the periplasm in a SecA-dependent, SRP-independent fashion. Collectively, our results provide compelling in vivo evidence that there is an SRP-dependent cotranslational targeting mechanism in
E. coli
and argue against a role for trigger factor in pathway discrimination.
Listeria monocytogenesσBRegulates Stress Response and Virulence Functions
Authors: Kazmierczak Mark J. , Mithoe Sharon C. , Boor Kathryn J. , Wiedmann Martin 
Published: September 2003

ABSTRACTWhile the stress-responsive alternative sigma factor σBhas been identified in different species ofBacillus,Listeria, andStaphylococcus, theσBregulon has been extensively characterized only inB. subtilis.We combined biocomputing and microarray-based strategies to identify σB-dependent genes in the facultative intracellular pathogenListeria monocytogenes. Hidden Markov model (HMM)-based searches identified 170 candidateσB-dependent promoter sequences in the strain EGD-e genome sequence. These data were used to develop a specialized, 208-gene microarray, which included 166 genes downstream of HMM-predicted σB-dependent promoters as well as selected virulence and stress response genes. RNA for the microarray experiments was isolated from both wild-type and ΔsigBnull mutantL. monocytogenescells grown to stationary phase or exposed to osmotic stress (0.5 M KCl). Microarray analyses identified a total of 55 genes with statistically significantσB-dependent expression under the conditions used in these experiments, with at least 1.5-fold-higher expression in the wild type over thesigBmutant under either stress condition (51 genes showed at least 2.0-fold-higher expression in the wild type). Of the 55 genes exhibiting σB-dependent expression, 54 were preceded by a sequence resembling the σBpromoter consensus sequence. Rapid amplification of cDNA ends-PCR was used to confirm the σB-dependent nature of a subset of eight selected promoter regions. Notably, theσB-dependentL. monocytogenesgenes identified through this HMM/microarray strategy included both stress response genes (e.g.,gadB,ctc, and the glutathione reductase genelmo1433) and virulence genes (e.g.,inlA,inlB, andbsh). Our data demonstrate that, in addition to regulating expression of genes important for survival under environmental stress conditions, σBalso contributes to regulation of virulence gene expression inL. monocytogenes.These findings strongly suggest thatσBcontributes toL. monocytogenesgene expression during infection.
In Vivo Evidence for TonB Dimerization
Authors: Sauter Annette , Howard S. Peter , Braun Volkmar 
Published: September 2003

ABSTRACTTonB, in complex with ExbB and ExbD, is required for the energy-dependent transport of ferric siderophores across the outer membrane ofEscherichia coli, the killing of cells by group B colicins, and infection by phages T1 and φ80. To gain insights into the protein complex, TonB dimerization was studied by constructing hybrid proteins from complete TonB (containing amino acids 1 to 239) [TonB(1-239)] and the cytoplasmic fragment of ToxR which, when dimerized, activates the transcription of the cholera toxin genectx. ToxR(1-182)-TonB(1-239) activated the transcription oflacZunder the control of thectxpromoter (Pctx::lacZ). Replacement of the TonB transmembrane region by the ToxR transmembrane region resulted in the hybrid proteins ToxR(1-210)-TonB(33-239) and ToxR(1-210)-TonB(164-239), of which only the latter activated Pctx::lacZtranscription. Dimer formation was reduced but not abolished in a mutant lacking ExbB and ExbD, suggesting that these complex components may influence dimerization but are not strictly required and that the N-terminal cytoplasmic membrane anchor and the C-terminal region are important for dimer formation. The periplasmic TonB fragment, TonB(33-239), inhibits ferrichrome and ferric citrate transport and induction of the ferric citrate transport system. This competition provided a means to positively screen for TonB(33-239) mutants which displayed no inhibition. Single point mutations of inactive fragments selected in this manner were introduced into complete TonB, and the phenotypes of the TonB mutant strains were determined. The mutations located in the C-terminal half of TonB, three of which (Y163C, V188E, and R204C) were obtained separately by site-directed mutagenesis, as was the isolated F230V mutation, were studied in more detail. They displayed different activity levels for various TonB-dependent functions, suggesting function-related specificities which reflect differences in the interactions of TonB with various transporters and receptors.
Temperature-Sensitive Growth and Decreased Thermotolerance Associated with
relA
Mutations in
Escherichia coli
Authors: Yang Xiaoming , Ishiguro Edward E. 
Published: September 2003

ABSTRACT

The
relA
gene of
Escherichia coli
encodes guanosine 3′,5′-bispyrophosphate (ppGpp) synthetase I, a ribosome-associated enzyme that is activated during amino acid starvation. The stringent response is thought to be mediated by ppGpp. Mutations in
relA
are known to result in pleiotropic phenotypes. We now report that three different
relA
mutant alleles,
relA1
,
relA2
, and
relA251
::
kan
, conferred temperature-sensitive phenotypes, as demonstrated by reduced plating efficiencies on nutrient agar (Difco) or on Davis minimal agar (Difco) at temperatures above 41°C. The
relA
-mediated temperature sensitivity was osmoremedial and could be completely suppressed, for example, by the addition of NaCl to the medium at a concentration of 0.3 M. The temperature sensitivities of the
relA
mutants were associated with decreased thermotolerance; e.g.,
relA
mutants lost viability at 42°C, a temperature that is normally nonlethal. The
spoT
gene encodes a bifunctional enzyme possessing ppGpp synthetase and ppGpp pyrophosphohydrolase activities. The introduction of the
spoT207
::
cat
allele into a strain bearing the
relA251
::
kan
mutation completely abolished ppGpp synthesis. This ppGpp null mutant was even more temperature sensitive than the strain carrying the
relA251
::
kan
mutation alone. The
relA
-mediated thermosensitivity was suppressed by certain mutant alleles of
rpoB
(encoding the β subunit of RNA polymerase) and
spoT
that have been previously reported to suppress other phenotypic characteristics conferred by
relA
mutations. Collectively, these results suggest that ppGpp may be required in some way for the expression of genes involved in thermotolerance.
Control of Enzyme II
scr
and Sucrose-6-Phosphate Hydrolase Activities in
Streptococcus mutans
by Transcriptional Repressor ScrR Binding to the
cis
-Active Determinants of the
scr
Regulon
Authors: Wang Bing , Kuramitsu Howard K. 
Published: September 2003

ABSTRACT

In
Streptococcus mutans
, enzyme II
scr
and sucrose-6-phosphate hydrolase are two important enzymes in the transport and metabolism of dietary sucrose. The
scr
regulon of
S. mutans
is composed of three genes,
scrA
and
scrB
, which code for enzyme II
scr
and sucrose-6-phosphate hydrolase, respectively, and
scrR
, which codes for a GalR-LacI-type transcription regulator. It was previously shown that expression of both
scrA
and
scrB
is similarly induced by sucrose. Mutation in the
scrR
gene resulted in increased expression of
scrB
relative to that in the wild-type strain. In this study, we employed DNA mobility shift and DNase I protection assays with a purified ScrR-histidine tag fusion protein to examine the DNA binding properties of ScrR to the promoter regions of the
scrA
and
scrB
genes. The results showed that ScrR bound specifically to the promoter regions of both
scrA
and
scrB
. Two regions with high affinity for ScrR in the promoter sequences of the
scrA
and
scrB
genes were identified by DNase I protection assays. One,
O
C
, which includes a 20-bp imperfect inverted-repeat sequence, is located between the two promoters, and the other,
O
B
, is located within the
scrB
promoter region containing a 37-bp imperfect direct-repeat sequence. Mutations of
O
B
and
O
C
resulted in constitutive transcription and expression of both the
scrA
and
scrB
genes. Our results indicated that
S. mutans
coordinates the activities of enzyme II
scr
and sucrose-6-phosphate hydrolase by transcriptional repressor ScrR binding to the promoter regions of the
scr
regulon.