bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pricing Default Risk in Mortgages
Authors: Epperson James F. , Kau James B. , Keenan Donald C. , Muller Walter J. 
Published: October 2003

This paper examines the valuation of fixed‐rate mortgages and the pricing of insurance against default on such mortgages. Both the mortgage and the insurance are treated as compound European put options. A put is the right, but not the obligation, to turn over an asset to another party for a specified payment, and being a European put indicates that this can only occur at a specified expiration date. The mortgage contract, and hence the insurance on it, fit into a European option framework because no rational borrower would ever choose to default until a payment is due. Mortgages are compound options in nature because at each payment data prior to the last one, the borrower either defaults or purchases a new option to default at the next payment date by making the scheduled payment.Since the current value of the mortgage is affected by options to default in the future, the problem is solved working backwards in time with the value of later options feeding into the earlier ones, so that the process builds on itself in a recursive fashion. Using familiar arguments from option‐pricing theory, the value of any of the assets in the model is expressed as the solution to a partial differential equation, where the terms of the contract yield the appropriate terminal conditions. Standard numerical procedures are then used to produce the value of the mortgage and the insurance under various economic conditions.The simulations indicate that the prime determinants of the value of the assets considered are the volatility of the house price and the volatility of the spot interest rate. Sensitivity tests show that changing either of these parameters affects the results substantially more than any of the other parameters examined.The paper completely analyzes the default option and insurance against default on the mortgage. It is one part of a complete model of fixed‐rate mortgages that would allow for both prepayment and default and treat the interaction of the two options. The general approach outlined in this paper can be used to develop such a model as well as to value any mortgage‐related security. In light of the increasing variety and the complexity of such instruments in the market today, the presentation of our approach to these valuation problems is perhaps the most important contribution of the paper.
An Evaluation of Hedonic Price Indexes for Thirty‐four Large SMSAs
Authors: Blackley Dixie M. , Follain James R. , Lee Haeduck 
Published: October 2003

The purpose of this paper is twofold. First, a set of price indexes are developed for thirty‐four metropolitan areas for the years 1975 and 1978. Indexes are also broken down by central city and suburb for twenty two of the metropolitan areas. These indexes measure variation in the price per unit of owner‐occupied housing stock and the price per unit of housing services of rental housing. Confidence intervals are constructed for the price indexes. It is found that the indexes are reasonably precise measures in that the typical ratio of the confidence interval to the predicted median rent or value is about 13%. Also, analysis of the confidence intervals indicates substantial and statistically significant variation in the price of housing stock and services among the metropolitan areas studied.One of the major benefits of this set of indexes is that it can be used to address one of the most important questions in real estate — Why do housing prices and rents vary among metropolitan areas and over time? Research projects are currently underway that use the data to address these two questions.
The Expanding Concept of Just Compensation and the Role of the Appraiser
Authors: Clauretie Terrence M. , Harju Melvin W. 
Published: October 2003

Compensation for injury to business profits in eminent domain actions has long been the focus of controversy. Historically, the federal and state courts explicitly excluded profits or goodwill from a determination of an award. Under this scheme the measure of compensation quickly settled on the market value of the condemned realty. Where injury to profits was especially evident, the courts sometimes allowed future returns to the business to be included as a factor which would influence the market value. They also developed, in some states, the “specialty” doctrine where the business was unique in any number of ways. Still, the measures of compensation adopted in these cases may have been inadequate to return the business owner to the same financial position as before a taking.In this paper, we review an expanded theory of just compensation currently emerging in the courts and indicate the measure of compensation necessary to effectively return the business owner to the same financial position after a taking as before. We also show that traditional awards have been less than adequate in cases where the cash flows accruing to a business are dependent, in some fashion, on the expropriated realty.Finally, we indicate the nature of awards under a jurisdiction which is unique in the sense that it explicitly requires consideration of all elements of loss resulting from expropriation of business properties. Those awards represent a departure from previous compensation measures and conform to those indicated by the theory developed in this paper. The role of the appraiser is outlined under this expanded system of compensation.
TYPES IN SLn
Authors: GOLDBERG DAVID , ROCHE ALAN 
Published: October 2003

Let $G = SL_n(F)$ where $F$ is a non-Archimedean local field. This paper concerns the smooth (complex) representation theory of $G$, specifically, the construction of types in $G$, in the sense of Bushnell and Kutzko. The main result describes a type for each non-supercuspidal component of the Bernstein decomposition of $G$. If this is combined with earlier work of Bushnell and Kutzko, it follows that $G$ admits a complete set of types. 2000 Mathematical Subject Classification: 22E50.
ALGEBRAIC CYCLES ON REAL VARIETIES AND ℤ/2-EQUIVARIANT HOMOTOPY THEORY
Authors: SANTOS PEDRO F. DOS 
Published: October 2003

In this paper the spaces of algebraic cycles on a real projective variety $X$ are studied as $\mathbb{Z}/2$-spaces under the action of the Galois group ${\rm Gal}(\mathbb{C}/\mathbb{R})$. In particular, the equivariant homotopy type of the group of algebraic $p$-cycles $\mathcal{Z}_p(\mathbb{P}_{\mathbb{C}}^n)$ is computed. A version of Lawson homology for real varieties is proposed. The real Lawson homology groups are computed for a class of real varieties.2000 Mathematical Subject Classification: primary 55P91; secondary 14C05, 19L47, 55N91.
Sequence Diversity ofTreponema pallidumsubsp.pallidum tprKin Human Syphilis Lesions and Rabbit-Propagated Isolates
Authors: LaFond Rebecca E. , Centurion-Lara Arturo , Godornes Charmie , Rompalo Anne M. , Van Voorhis Wesley C. , Lukehart Sheila A. 
Published: October 2003

ABSTRACTThetprKgene ofTreponema pallidumsubsp.pallidum, the causative agent of venereal syphilis, belongs to a 12-member gene family and encodes a protein with a predicted cleavable signal sequence and predicted transmembrane domains. Except for the Nichols type strain, all rabbit-propagated isolates ofT. pallidumexamined thus far are comprised of mixed populations of organisms with heterogeneoustprKsequences. We show thattprKsequences in treponemes obtained directly from syphilis patients are also heterogeneous. Clustering analysis demonstrates that primary chancretprKsequences are more likely to cluster within a sample than among samples and that tighter clustering is seen within chancre samples than within rabbit-propagated isolates. Closer analysis oftprKsequences from a rabbit-propagated isolate reveals that individual variable regions have different levels of diversity, suggesting that variable regions may have different intrinsic rates of sequence change or may be under different levels of selection. Most variable regions show increased sequence diversity upon passage. We speculate that the diversification oftprKduring infection allows organisms to evade the host immune response, contributing to reinfection and persistent infection.
Molecular Evolution of thedotAGene inLegionella pneumophila
Authors: Ko Kwan Soo , Hong Seong Karp , Lee Hae Kyung , Park Mi-Yeoun , Kook Yoon-Hoh 
Published: October 2003

ABSTRACTThe molecular evolution ofdotA, which is related to the virulence ofLegionella pneumophila, was investigated by comparing the sequences of 15 reference strains (serogroups 1 to 15). It was found thatdotAhas a complex mosaic structure. The wholedotAgene ofLegionella pneumophilasubsp.pneumophilaserogroups 2, 6, and 12 has been transferred fromLegionella pneumophilasubsp.fraseri. A discrepancy was found between the trees inferred from the nucleotide and deduced amino acid sequences ofdotA, which suggests that multiple hits, resulting in synonymous substitutions, have occurred. Gene phylogenies inferred from three different segments (the 5′-end region, the central, large periplasmic domain, and the 3′-end region) showed impressively dissimilar topologies. This was concordant with the sequence polymorphisms, indicating that each region has experienced an independent evolutionary history, and was evident even within the same domain of each strain. For example, the PP2 domain was found to have a heterogeneous structure, which led us hypothesize that thedotAgene ofL. pneumophilamay have originated from two or more different sources. Comparisons of synonymous and nonsynonymous substitutions demonstrated that the PP2 domain has been under strong selective pressure with respect to amino acid change. Split decomposition analysis also supported the intragenic recombination ofdotA. Multiple recombinational exchange within thedotAgene, encoding an integral cytoplasmic membrane protein that is secreted, probably provided increased fitness in certain environmental niches, such as within a particular biofilm community or species of amoebae.
Molecular Characterization of the Mg
2+
-Responsive PhoP-PhoQ Regulon in
Salmonella enterica
Authors: Lejona Sergio , Aguirre Andrés , Cabeza María Laura , Véscovi Eleonora García , Soncini Fernando C. 
Published: October 2003

ABSTRACT

The PhoP/PhoQ two-component system controls the extracellular magnesium deprivation response in
Salmonella enterica
. In addition, several virulence-associated genes that are mainly required for intramacrophage survival during the infection process are under the control of its transcriptional regulation. Despite shared Mg
2+
modulation of the expression of the PhoP-activated genes, no consensus sequence common to all of them could be detected in their promoter regions. We have investigated the transcriptional regulation and the interaction of the response regulator PhoP with the promoter regions of the PhoP-activated loci
phoPQ
,
mgtA
,
slyB
,
pmrD
,
pcgL
,
phoN
,
pagC
, and
mgtCB
. A direct repeat of the heptanucleotide sequence (G/T)GTTTA(A/T) was identified as the conserved motif recognized by PhoP to directly control the gene expression of the first five loci, among which the first four are ancestral to enterobacteria. On the other hand, no direct interaction of the response regulator with the promoter of
phoN
,
pagC
, or
mgtCB
was apparent by either in vitro or in vivo assays. These loci are
Salmonella
specific and were probably acquired by horizontal DNA transfer. Besides, sequence analysis of
pag
promoters revealed the presence of a conserved PhoP box in 6 out of the 12 genes analyzed. Our results strongly suggest that the expression of a set of Mg
2+
-controlled genes is driven by PhoP via unknown intermediate regulatory mechanisms that could also involve ancillary factors.
Characterization of the Integrase Gene and Attachment Site for the
Myxococcus xanthus
Bacteriophage Mx9
Authors: Julien Bryan 
Published: October 2003

ABSTRACT

Bacteriophage Mx9 is a temperate phage that infects
Myxococcus xanthus
. It lysogenizes the bacteria by integrating into the bacterial chromosome by site-specific recombination at one of two sites,
attB1
or
attB2
. Integration at
attB1
results in deletion of DNA between the two
attB
sites. The
attB2
site lies within the 5′ region of the
M. xanthus
tRNA
Gly
gene. Mx9 integration requires a single protein, Int. Analysis of integration revealed that the phage attachment site (
attP
) is contained in the
int
gene and that upon integration, the 3′ end of the
int
gene is altered. Plasmids containing fusions of the
pilA
or
mgl
promoter to
lacZ
integrated at either Mx9
attB
site have higher levels of transcription than the same fusions integrated at the Mx8
attB
site.
A New Heat Shock Gene,agsA, Which Encodes a Small Chaperone Involved in Suppressing Protein Aggregation inSalmonella entericaSerovar Typhimurium
Authors: Tomoyasu Toshifumi , Takaya Akiko , Sasaki Tomomi , Nagase Takahiro , Kikuno Reiko , Morioka Mizue , Yamamoto Tomoko 
Published: October 2003

ABSTRACTWe discovered a novel small heat shock protein (sHsp) named AgsA (aggregation-suppressing protein) in the thermally aggregated fraction from aSalmonella entericaserovar TyphimuriumdnaK-null strain. The −10 and −35 regions upstream of the transcriptional start site of theagsAgene are characteristic of σ32- and σ72-dependent promoters. AgsA was strongly induced by high temperatures. The similarity between AgsA and the other two sHsps ofSalmonellaserovar Typhimurium, IbpA and IbpB, is rather low (around 30% amino acid sequence identity). Phylogenetic analysis suggested that AgsA arose from an ancient gene duplication or amplification at an early evolutionary stage of gram-negative bacteria. Here we show that overproduction of AgsA partially complements the ΔdnaK52thermosensitive phenotype and reduces the amount of heat-aggregated proteins in both ΔdnaK52and ΔrpoHmutants ofEscherichia coli. These data suggest that AgsA is an effective chaperone capable of preventing aggregation of nonnative proteins and maintaining them in a state competent for refolding inSalmonellaserovar Typhimurium at high temperatures.
Description and Interpretation of Adaptive Evolution of
Escherichia coli
K-12 MG1655 by Using a Genome-Scale In Silico Metabolic Model
Authors: Fong Stephen S. , Marciniak Jennifer Y. , Palsson Bernhard Ø. 
Published: October 2003

ABSTRACT

Genome-scale in silico metabolic networks of
Escherichia coli
have been reconstructed. By using a constraint-based in silico model of a reconstructed network, the range of phenotypes exhibited by
E. coli
under different growth conditions can be computed, and optimal growth phenotypes can be predicted. We hypothesized that the end point of adaptive evolution of
E. coli
could be accurately described a priori by our in silico model since adaptive evolution should lead to an optimal phenotype. Adaptive evolution of
E. coli
during prolonged exponential growth was performed with M9 minimal medium supplemented with 2 g of α-ketoglutarate per liter, 2 g of lactate per liter, or 2 g of pyruvate per liter at both 30 and 37°C, which produced seven distinct strains. The growth rates, substrate uptake rates, oxygen uptake rates, by-product secretion patterns, and growth rates on alternative substrates were measured for each strain as a function of evolutionary time. Three major conclusions were drawn from the experimental results. First, adaptive evolution leads to a phenotype characterized by maximized growth rates that may not correspond to the highest biomass yield. Second, metabolic phenotypes resulting from adaptive evolution can be described and predicted computationally. Third, adaptive evolution on a single substrate leads to changes in growth characteristics on other substrates that could signify parallel or opposing growth objectives. Together, the results show that genome-scale in silico metabolic models can describe the end point of adaptive evolution a priori and can be used to gain insight into the adaptive evolutionary process for
E. coli
.
Analysis of Specific Binding Involved in Genomic Packaging of the Double-Stranded-RNA Bacteriophage φ6
Authors: Qiao Xueying , Qiao Jian , Mindich Leonard 
Published: October 2003

ABSTRACT
The genomes of bacteriophage φ6 and its relatives are packaged through a mechanism that involves the recognition and translocation of the three different plus-strand transcripts of the segmented double-stranded-RNA genomes into preformed polyhedral structures called procapsids or inner cores. The packaging requires the hydrolysis of nucleoside triphosphates and takes place in the order segment S-segment M, segment L. Packaging is dependent upon unique sequences of about 200 nucleotides near the 5′ ends of plus-strand transcripts of the three genomic segments. It appears that P1 is the determinant of the RNA binding sites. Directed mutation of P1 was used to locate regions that are important for genomic packaging. Specific binding of RNA to the exterior of the procapsid was dependent upon ATP, and a region that showed a high level of cross-linking to phage-specific RNA was located. Antibodies to peptide sequences were prepared, and their abilities to bind to the exterior of procapsids were determined. Sites sensitive to trypsin and to factor Xa were determined as well.
Routing on Triangles, Tori and Honeycombs
Authors: Sibeyn Jop F. 
Published: October 2003

The standard n × n torus consists of two sets of axes: horizontal and vertical ones. For routing h-relations, the bisection bound gives a lower bound of h · n/4. Several algorithms nearly matching this bound have been given. In this paper we analyze the routing capacity of modified tori: tessellations of the plane with triangles or hexagons and tori with added diagonals. On some of these networks the ratio of routing capacity and degree is higher than for ordinary tori, even though they are as easily constructed. Hence, they may constitute more cost effective alternatives. For networks with n2 PUs, we get the following results: on a torus of hexagons, node degree 3, h-relations are performed in 0.37 · h · n steps; on a torus of triangles, node degree 6, in 0.13 · h · n; and on a torus with added diagonals, node degree 8, in h · n/12. The latter result matches the bisection bound for this network. Even faster is the routing on a torus of hexagons with diagonals, node degree 12: 0.053 · h · n. The algorithms are simple, inspired by the algorithm of Valiant and Brebner. The results can easily be extended to sorting, dynamic routing or routing for average-case inputs.
Patterns and Long Range Correlations in Idealized Granular Flows
Authors: Orza J. A. G. , Brito R. , van Noije T. P. C. , Ernst M. H. 
Published: October 2003

An initially homogeneous freely evolving fluid of inelastic hard spheres develops inhomogeneities in the flow field u(r, t) (vortices) and in the density field n (r, t)(clusters), driven by unstable fluctuations, δa = {δn, δu}. Their spatial correlations, <δa(r, t)δa(r′,t)>, as measured in molecular dynamics simulations, exhibit long range correlations; the mean vortex diameter grows as [Formula: see text]; there occur transitions to macroscopic shearing states, etc. The Cahn–Hilliard theory of spinodal decomposition offers a qualitative understanding and quantitative estimates of the observed phenomena. When intrinsic length scales are of the order of the system size, effects of physical boundaries and periodic boundaries (finite size effects in simulations) are important.
Bridging Functional MR Images and Scientific Inference: Reproducibility Maps
Authors: Liou Michelle , Su Hong-Ren , Lee Juin-Der , Cheng Philip E. , Huang Chien-Chih , Tsai Chih-Hsin 
Published: October 2003

AbstractHistorically, reproducibility has been the sine qua non of experimental findings that are considered to be scientifically useful. Typically, findings from functional magnetic resonance imaging (fMRI) studies are assessed with statistical parametric maps (SPMs) using a p value threshold. However, a smaller p value does not imply that the observed result will be reproducible. In this study, we suggest interpreting SPMs in conjunction with reproducibility evidence. Reproducibility is defined as the extent to which the active status of a voxel remains the same across replicates conducted under the same conditions. We propose a methodology for assessing reproducibility in functional MR images without conducting separate experiments. Our procedures include the empirical Bayes method for estimating effects due to experimental stimuli, the threshold optimization procedure for assigning voxels to the active status, and the construction of reproducibility maps. In an empirical example, we implemented the proposed methodology to construct reproducibility maps based on data from the study by Ishai et al. (2000). The original experiments involved 12 human subjects and investigated brain regions most responsive to visual presentation of 3 categories of objects: faces, houses, and chairs. The brain regions identified included occipital, temporal, and fusiform gyri. Using our reproducibility analysis, we found that subjects in one of the experiments exercised at least 2 mechanisms in responding to visual objects when performing alternately matching and passive tasks. One gave activation maps closer to those reported in Ishai et al., and the other had related regions in the precuneus and posterior cingulate. The patterns of activated regions are reproducible for at least 4 out of 6 subjects involved in the experiment. Empirical application of the proposed methodology suggests that human brains exhibit different strategies to accomplish experimental tasks when responding to stimuli. It is important to correlate activations to subjects' behavior such as reaction time and response accuracy. Also, the latency between the stimulus presentation and the peak of the hemodynamic response function varies considerably among individual subjects according to types of stimuli and experimental tasks. These variations per se also deserve scientific inquiries. We conclude by discussing research directions relevant to reproducibility evidence in fMRI.
Studies in Cognition: The Problems Solved and Created by Transcranial Magnetic Stimulation
Authors: Robertson E. M. , Théoret H. , Pascual-Leone A. 
Published: October 2003

Abstract
The application of transcranial magnetic stimulation (TMS) to investigate important questions in cognitive neuroscience has increased considerably in the last few years. TMS can provide substantial insights into the nature and the chronometry of the computations performed by specific cortical areas during various aspects of cognition. However, the use of TMS in cognitive studies has many potential perils and pitfalls. Although TMS can help bridge the gap between psychological models and brain-based arguments of cognitive functions, hypothesis-driven carefully designed experiments that acknowledge the current limitations of TMS are critical.
Perceptual History Influences Neural Responses to Face and Body Postures
Authors: Jellema Tjeerd , Perrett David I. 
Published: October 2003

Abstract
We show that under natural viewing, the responses of cells in the temporal lobe of the macaque to the sight of static head and body postures is controlled by the sight of immediately preceding actions. Cells in the anterior part of the superior temporal sulcus responded vigorously to the sight of a face or body posture that followed a particular body action, but not when it followed other actions. The effective action or posture presented in isolation or in different sequences failed to produce a response. Our results demonstrate that cells in the temporal cortex could support the formation of expectations about impending behavior of others.