bluuebunny/crossref_metadata_2025 huggingface dataset:
A Genome Sequence Survey Shows that the Pathogenic YeastCandida parapsilosisHas a DefectiveMTLa1Allele at Its Mating Type Locus
Authors: Logue Mary E. , Wong Simon , Wolfe Kenneth H. , Butler Geraldine
Published: June 2005

Candida parapsilosisis responsible for ca. 15% ofCandidainfections and is of particular concern in neonates and surgical intensive care patients. The related speciesCandida albicanshas recently been shown to possess a functional mating pathway. To analyze the analogous pathway inC. parapsilosis, we carried out a genome sequence survey of the type strain. We identified ca. 3,900 genes, with an average amino acid identity of 59% withC. albicans. Of these, 23 are predicted to be predominantly involved in mating. We identified a genomic locus homologous to theMTLamating type locus ofC. albicans, but theC. parapsilosistype strain has at least two internal stop codons in theMTLa1open reading frame, and two predicted introns are not spliced. These stop codons were present inMTLa1of all eightC. parapsilosisisolates tested. Furthermore, we found that all isolates ofC. parapsilosistested appear to contain only theMTLaidiomorph at the presumptive mating locus, unlikeC. albicansandC. dubliniensis.MTLαsequences are present but at a different chromosomal location. It is therefore likely that all (or at least the majority) ofC. parapsilosisisolates have a mating pathway that is either defective or substantially different from that ofC. albicans.
Ability of Sit4p To Promote K+Efflux via Nha1p Is Modulated by Sap155p and Sap185p
Authors: Manlandro Cara Marie A. , Haydon Devon H. , Rosenwald Anne G.
Published: June 2005

We demonstrate here thatSAP155encodes a negative modulator of K+efflux in the yeastSaccharomyces cerevisiae. Overexpression ofSAP155decreases efflux, whereas deletion increases efflux. In contrast, a homolog ofSAP155, calledSAP185, encodes a positive modulator of K+efflux: overexpression ofSAP185increases efflux, whereas deletion decreases efflux. Two other homologs,SAP4andSAP190, are without effect on K+homeostasis. BothSAP155andSAP185require the presence ofSIT4for function, which encodes a PP2A-like phosphatase important for the G1-S transition through the cell cycle. Overexpression of either the outwardly rectifying K+channel, Tok1p, or the putative plasma membrane K+/H+antiporter, Kha1p, increases efflux in both wild-type andsit4Δstrains. However, overexpression of the Na+-K+/H+antiporter, Nha1p, is without effect in asit4Δ strain, suggesting that Sit4p signals to Nha1p. In summary, the combined activities of Sap155p and Sap185p appear to control the function of Nha1p in K+homeostasis via Sit4p.
Saccharomyces cerevisiae
Heat Shock Transcription Factor Regulates Cell Wall Remodeling in Response to Heat Shock
Authors: Imazu Hiromi , Sakurai Hiroshi
Published: June 2005

The heat shock transcription factor Hsf1 of the yeast
Saccharomyces cerevisiae
regulates expression of genes encoding heat shock proteins and a variety of other proteins as well. To better understand the cellular roles of Hsf1, we screened multicopy suppressor genes of a temperature-sensitive
hsf1
mutation. The
RIM15
gene, encoding a protein kinase that is negatively regulated by the cyclic AMP-dependent protein kinase, was identified as a suppressor, but Rim15-regulated stress-responsive transcription factors, such as Msn2, Msn4, and Gis1, were unable to rescue the temperature-sensitive growth phenotype of the
hsf1
mutant. Another class of suppressors encoded cell wall stress sensors, Wsc1, Wsc2, and Mid2, and the GDP/GTP exchange factor Rom2 that interacts with these cell wall sensors. Activation of a protein kinase, Pkc1, which is induced by these cell wall sensor proteins upon heat shock, but not activation of the Pkc1-regulated mitogen-activated protein kinase cascade, was necessary for the
hsf1
suppression. Like Wsc-Pkc1 pathway mutants,
hsf1
cells exhibited an osmotic remedial cell lysis phenotype at elevated temperatures. Several of the other suppressors were found to encode proteins functioning in cell wall organization. These results suggest that Hsf1 in concert with Pkc1 regulates cell wall remodeling in response to heat shock.
ABG1
, a Novel and Essential
Candida albicans
Gene Encoding a Vacuolar Protein Involved in Cytokinesis and Hyphal Branching
Authors: Veses Verónica , Casanova Manuel , Murgui Amelia , Domínguez Ángel , Gow Neil A. R. , Martínez José P.
Published: June 2005

Immunoscreening of a
Candida albicans
expression library resulted in the isolation of a novel gene encoding a 32.9-kDa polypeptide (288 amino acids), with 27.7% homology to the product of
Saccharomyces cerevisiae
YGR106c, a putative vacuolar protein. Heterozygous mutants in this gene displayed an
a
ltered
b
udding
g
rowth pattern, characterized by the formation of chains of buds, decreasingly in size towards the apex, without separation of the daughter buds. Consequently, this gene was designated
ABG1
. A conditional mutant for
ABG1
with the remaining allele under the control of the
MET3
promoter did not grow in the presence of methionine and cysteine, demonstrating that
ABG1
was essential for viability. Western analysis revealed the presence of a major 32.9-kDa band, mainly in a particulate fraction (P40) enriched in vacuoles, and tagging with green fluorescent protein confirmed that Abg1p localized to the vacuole. Vacuole inheritance has been linked to the regulation of branching frequency in
C. albicans
. Under repressing conditions, the conditional mutant had an increased frequency of branching under hyphal inducing conditions and an altered sensitivity to substances that interfered with cell wall assembly. Repression of
ABG1
in the conditional mutant strain caused disturbance of normal size and number of vacuoles both in yeast and mycelial cells and also in the asymmetric vacuole inheritance associated with the characteristic pattern of germ tubes and branching in
C. albicans
. These observations indicate that
ABG1
plays a key role in vacuole biogenesis, cytokinesis, and hyphal branching.
Small Sense and Antisense RNAs Derived from a Telomeric Retroposon Family in
Giardia intestinalis
Authors: Ullu Elisabetta , Lujan Hugo D. , Tschudi Christian
Published: June 2005

Sequencing of a library of small RNAs from
Giardia intestinalis
identified a novel class of small sense and antisense RNAs homologous to the retroposon family GilT/Genie1 that is located at certain telomeres. These small RNAs may contribute to silencing GilT expression via the RNA interference pathway.
A Cysteine-Rich Extracellular Protein Containing a PA14 Domain Mediates Quorum Sensing in
Dictyostelium discoideum
Authors: Kolbinger Alexandra , Gao Tong , Brock Debbie , Ammann Robin , Kisters Axel , Kellermann Joseph , Hatton Diane , Gomer Richard H. , Wetterauer Birgit
Published: June 2005

Much remains to be understood about quorum-sensing factors that allow cells to sense their local density.
Dictyostelium discoideum
is a simple eukaryote that grows as single-celled amoebae and switches to multicellular development when food becomes limited. As the growing cells reach a high density, they begin expressing discoidin genes. The cells secrete an unknown factor, and at high cell densities the concomitant high levels of the factor induce discoidin expression. We report here the enrichment of discoidin-inducing complex (DIC), an ∼400-kDa protein complex that induces discoidin expression during growth and development. Two proteins in the DIC preparation, DicA1 and DicB, were identified by sequencing proteolytic digests. DicA1 and DicB were expressed in
Escherichia coli
and tested for their ability to induce discoidin during growth and development. Recombinant DicB was unable to induce discoidin expression, while recombinant DicA1 was able to induce discoidin expression. This suggests that DicA1 is an active component of DIC and indicates that posttranslational modification is dispensable for activity. DicA1 mRNA is expressed in vegetative and developing cells. The mature secreted form of DicA1 has a molecular mass of 80 kDa and has a 24-amino-acid cysteine-rich repeat that is similar to repeats in
Dictyostelium
proteins, such as the extracellular matrix protein ecmB/PstA, the prespore cell-inducing factor PSI, and the cyclic AMP phosphodiesterase inhibitor PDI. Together, the data suggest that DicA1 is a component of a secreted quorum-sensing signal regulating discoidin gene expression during
Dictyostelium
growth and development.
THE STATIC CONFINING POTENTIAL FOR QCD IN THE MANDELSTAM MODEL
Authors: BOTELHO LUIZ C. L.
Published: June 2005

We evaluate explicitly the quark–antiquark static potential on Quantum Chromodynamics QCD ( SU (3)) by using the dimensional regularization scheme in the context of the Mandelstam approximation for the gluonic interaction. We obtain its charge confining behavior in opposition to the expected result of a screening charge dynamics. Additionally we present a connection between the Mandelstam fourth-order propagator and the Polyakov's axion field-string representation for Wilson loops on QCD ( SU (∞)).
COMPLEX MODULI OF PHYSICAL QUANTA
Authors: ISIDRO JOSÉ M.
Published: June 2005

Classical mechanics can be formulated using a symplectic structure on classical phase space, while quantum mechanics requires a complex-differentiable structure on that same space. Complex-differentiable structures on a given real manifold are often not unique. This paper is devoted to analysing the dependence of the notion of a quantum on the complex-differentiable structure chosen on classical phase space.
RELATIVISTIC DESCRIPTION OF THE CHARMONIUM MASS SPECTRUM
Authors: EBERT D. , FAUSTOV R. N. , GALKIN V. O.
Published: June 2005

The charmonium mass spectrum is considered in the framework of the constituent quark model with the relativistic treatment of the c quark. The obtained masses are in good agreement with the existing experimental data including the mass of ηc(2S).
COMPARATIVE OBSERVATION OF THE NMR SPIN-LATTICE AND SPIN-SPIN RELAXATION IN MOLTEN AND CROSS-LINKED POLIBUTADIENE
Authors: TODICA M.
Published: June 2005

The molten and cross-linked polybutadiene were observed by NMR methods in order to disclose the influence of the presence of the temporary and permanent junctions between the polymeric chains on the relaxation of the longitudinal and transverse magnetization. The residual dipolar interaction determined by the entanglements of the polymeric chains is observed by the pseudo-solid echo method and is associated with the existence of the temporary network.
SPECTROSCOPIC STUDIES OF SOME PHOSPHATE GLASSES WITH MOLYBDENUM IONS
Authors: MAGDAS D. A. , COZAR O. , ARDELEAN I. , DAVID L.
Published: June 2005

The structure of x MoO 3·(100-x)[2 P 2 O 5· PbO ] glass system with 0≤x≤50 mol % is investigated by IR and Raman spectroscopies.

The characteristic bands of the glass matrix [2 P 2 O 5· PbO ] and MoO 3 oxide due to the stretching and bending vibrations are identified. This allows us to identify the specific structural units which occur in these glasses and to deduce the role of the MoO 3 oxide on the structural aspects of 2 P 2 O 5· PbO network.

At high MoO 3 content a depolymerization of the phosphate structure appears and the short phosphate chain units or ring structures are formed too.
IMPEDANCE SPECTROSCOPIC STUDY OF Ca1-xYxTi1-xCoxO3 CERAMICS BASED HUMIDITY SENSOR
Authors: KATARE RAJESH KUMAR , PANDEY LAKSHMAN , THAKUR O. P. , PARKASH OM , KUMAR DEVENDRA
Published: June 2005

The results of an investigation of humidity sensors based on ceramic material are discussed. It is widely approved that the ceramics based humidity sensor is superior to the polymer one due to their better thermal stability over a variety of chemical species, wide range of operating temperature and rapid response to change of humidity. Properties of humidity sensor based on ceramic system Ca 1-x Y x Ti 1-x Co x O 3 are presented. The role of each part of the sensitive material in the electrical conduction process is determined based on measurements and calculated equivalent circuits. The proposed model describes the water absorption on grain and grain boundaries surfaces with very good fit to the experimental data. A new approach to the modeling of the impedance frequency dependence by means of an equivalent circuit yields very promising results for sensors.
THE METASTABLE PHASE DIAGRAM OF THE BLUME–EMERY–GRIFFITHS MODEL IN ADDITION TO THE EQUILIBRIUM PHASE DIAGRAM USING THE PAIR APPROXIMATION
Authors: ERDİNÇ AHMET , KESKİN MUSTAFA
Published: June 2005

As a continuation of our previously published work, the metastable phase diagram of the Blume–Emery–Griffiths model with the arbitrary bilinear (J), biquadratic (K) and crystal field interaction (D) is presented in addition to the equilibrium phase diagram in (T/K, J/K) and (T/K, D/K) plane by using the pair approximation of the cluster variation method on a body centered cubic lattice. We also calculate the phase transitions for the unstable branches of order parameters. The calculated first- and second-order phase boundaries of the unstable branches of the order parameters are superimposed on the equilibrium phase diagram and metastable phase diagram. It is found that the metastable phase diagram and the first- and second-order phase boundaries for unstable branches of order parameters always exist at low temperatures, which are consistent with the experimental and theoretical works.
EFFECT OF CeO2ON SINTERING TEMPERATURE AND PIEZOELECTRIC PROPERTIES PZT (Zr:Ti = 52:48) CERAMICS
Authors: SRIMAUNGSONG P. , UDOMKAN N. , PDUNGSAP L. , WINOTAI P.
Published: June 2005

The purpose of this research is to investigate the structure of lead zirconate titanate ceramics (Zr:Ti = 52:48) doped with CeO2and corresponding properties such as micro-structural properties, physical properties, dielectric constant (εr), piezoelectric properties (kp, Qm, and d33), and the ferroelectric property. The specimens were prepared via a conventional mixed oxide method and sintered at 1200°C. Rietveld refinement of X-ray diffraction patterns resulted in the P4mm tetragonal structure for all samples. At a high dopant content (10 mol%), pyrochlore phases of CeO2appeared which caused the detriment of dielectric and piezoelectric properties. At a low dopant content (1 mol%), Ce4+ions entered the B site with isovalent dopant effects, and clearly resulted lower values of εr, and kpcompared with those of the undoped sample. The hysteresis loops showed ferroelectric properties for all samples. Microstructures displayed dense grain distribution and thus yielded a high density. The additional phase of CeO2was clearly observed for 10 mol% doping which implied it was overdoped. Finally, the Curie temperature has been found to decrease with increasing dopant content, as determined from high temperature X-ray diffraction and differential scanning calorimetry.
THE VARIETIES OF INTENSITY CORRELATION TIME WITH INPUT SIGNAL IN A SINGLE-MODE LASER WITH BIAS SIGNAL MODULATION
Authors: CHEN LI-MEI , CAO LI , WU DA-JIN
Published: June 2005

The varieties of intensity correlation time T with input signal are studied for gain-noise model of a single-mode laser driven by colored pump noise and colored quantum noise with colored cross-correlation with a bias signal modulation in this paper. By using the linear approximation method, it is found that a minimum (i.e. suppression) in the curves of the intensity correlation time T versus the bias current i0exists when the noise correlation coefficient λ is negative; and the intensity correlation time T increases monotonously with the increase of i0when λ≥0. In addition, we also analyze the curve of T versus the signal frequency Ω, find that no matter what the value of λ is, a minimum (i.e. suppression) in the T-Ω curves always exists.
INFLUENCE OF THE PREPARATION CONDITIONS AND THERMAL TREATMENT ON THE STRUCTURE OF THE B2O3-BaO-Fe2O3 SYSTEM
Authors: RUSU DORINA , CARRASCO M. F. , TODERAS MONICA , ARDELEAN I.
Published: June 2005

The structure of x Fe 2 O 3·(100-x)[3 B 2 O 3· BaO ] system with 0≤x≤50 mol % was studied by DTA, X-ray diffraction, density, optical microscopy and EPR measurements in vitreous and partial crystallized state, the samples being obtained by under cooling method. The data obtained show that, by melting the samples at Te = 1200°C or Te = 1250° C , glasses for x≤35 mol % were obtained, and the forming of crystalline microprecipitates of Fe 2 O 3 in the sample with x = 50 mol %. It was also established that the thermal treatment at 565°C without and in the presence of magnetic field of 0.7 T is influencing the forming and the development of the Fe 2 O 3 microcrystals in samples with x≥35 mol %. The samples melted at Tc = 1200° C and Tc = 1250° C were studied by magnetic susceptibility measurements which evidenced similar results with those obtained by EPR. Also, the magnetic measurements show that for the thermal untreated samples the iron ions participate at superexchange interactions for x≥5 mol % and for x≥10 mol %, respectively.
ELECTRONIC PATHWAYS IN PHOTOACTIVATED REPAIR OF UV MUTATED DNA
Authors: BOHR HENRIK , JALKANEN K. J. , BARY MALIK F.
Published: June 2005

An investigation of the physics, underlying the damage caused to DNA by UV radiation and its subsequent repair via a photoreactivation mechanism, is presented in this study. Electronic pathways, starting from the initial damage to the final repair process, are presented. UV radiation is absorbed to create a hole-excited thymine or other pyrimidine that subsequently is responsible for the formation of a dimer. The negative-ion of the cofactor riboflavin, FADH-, formed by the exposure of the photolyase protein to visible light, interacts with the hole-excited electronic orbital of the thymine dimer inducing a photon-less Auger transition, which restores the two thymines to the ground state, thereby detaching the lesion and repairing the DNA. Density functional theoretical calculations supporting the theory are presented. The mechanism involves the least amount of energy dissipation and is charge neutral. It also avoids radiation damage in the repair process. Recent experimental data are compatible with this theory.
BCS-LIKE APPROXIMATION IN A TWO-BAND MODEL FOR SUPERCONDUCTIVITY IN MgB2
Authors: MACOCIAN EUGEN-VICTOR
Published: June 2005

The BCS limit of a two-band model for superconductivity in MgB 2 is discussed and the temperature dependence of the gap functions is calculated together with their values at T = 0. We have studied the effect of interband coupling on the order parameters and critical temperature. The validity of the approximation was investigated by direct comparison with more accurate Eliashberg calculation and it was found that the BCS-like model is appropriate for temperatures up to T ~ 10 K . The two-band superconductivity in MgB 2 has been extensively studied in the literature, in Eliashberg or weak-coupling calculations, as well as in ab initio evaluations of electron–phonon interaction. Here we find from an analytical calculation the well known result that the ratio 2Δ/Tc is no longer universal in the multiband model, in contrast with the classical single-band BCS model.
HYDROGENATED AMORPHOUS CARBON FILMS PREPARED BY XeCl EXCIMER PULSED LASER DEPOSITION USING COMPOSITIONAL GRAPHITE AND CAMPHOR TARGET FOR SOLAR CELL APPLICATIONS
Authors: RUSOP M. , TIAN X. M. , SOGA T. , JIMBO T. , UMENO M.
Published: June 2005

Hydrogenated amorphous carbon films ( a - C : H ) were deposited on p -type silicon ( a - C : H / p - Si ) and quartz substrates by excimer laser at room temperature using mixture ratios 1 to 9 and 3 to 7 of camphor to graphite by weight percentages. The presence of hydrogen in the a-C:H films has been confirmed by Fourier transform infrared spectroscopy (FTIR) measurements. The structure and optical properties of a - C : H films were respectively investigated by Raman scattering and UV-visible spectroscopy. The increase of sp 3 sites in the a - C : H films has also been confirmed by the Raman spectra spectroscopy analysis. The increase of the optical band gap with higher camphor percentage in the target was believed to be due to the increase of the sp 3 hybrid forms of carbon arising from camphor incorporation. The formation of a heterojunction between the a - C : H film and Si substrate was confirmed by current–voltage (I–V) measurement. The structure of a - C : H / p - Si cells deposited using mixture ratios 1 to 9 of camphor to graphite by weight percentages showed better photovoltaic characteristics with an open-circuit voltage of 400 mV and short-circuit current density of about 15 mA/cm2 under AM 1.5 (100 mW/cm2 at room temperature) illumination. The energy conversion efficiency and fill factor were found to be approximately 2.1% and 0.38, respectively. The carbon layer contributed to the energy conversion efficiency in the lower wavelength region has been proved by the quantum efficiency measurement.
HARTREE–FOCK–BOGOLIUBOV STUDIES OF BILAYER ν = 2 QUANTUM HALL SYSTEMS
Authors: SHIMODA YUICHI , NAKAJIMA TATSUYA , SAWADA ANJU
Published: June 2005

Excitation spectra in bilayer quantum Hall systems at total Landau-level filling ν = 2 are studied by the Hartree–Fock–Bogoliubov (HFB) approximation. The systems have the spin degrees of freedom in addition to the layer degrees of freedom described in terms of pseudospin. On the excitation spectrum from the spin-singlet and pseudospin-polarized ground state, this approximation fully preserves the spin rotational symmetry and thus can give both spin-triplet and spin-singlet excitations systematically. It is also found that the ground state is pseudospin squeezed because of pseudospin correlations and that the HFB approximation can describe ground-state properties better than other approximations.
SOME REMARKS ON MEAN-VARIANCE HEDGING FOR DISCONTINUOUS ASSET PRICE PROCESSES
Authors: ARAI TAKUJI
Published: June 2005

Mean-variance hedging for the discontinuous semimartingale case is obtained under some assumptions related to the variance-optimal martingale measure. In the present paper, two remarks on it are discussed. One is an extension of Hou–Karatzas' duality approach from the continuous case to discontinuous. Another is to prove that there is the consistency with the case where the mean-variance trade-off process is continuous and deterministic. In particular, one-dimensional jump diffusion models are discussed as simple examples.
A NOTE ON ASSET BUBBLES IN CONTINUOUS-TIME
Authors: CASSESE GIANLUCA
Published: June 2005

In this paper we propose a model of asset prices consistent with the no-arbitrage principle but allowing for the existence of "bubbles". The structure of bubbles is explicitly characterized and we show that, for example, they may be of either sign. Furthermore, we discuss the existence of bubbles under alternative definitions of absence of arbitrage opportunities.
PARTIAL EQUILIBRIUM AND MARKET COMPLETION
Authors: HU YING , IMKELLER PETER , MÜLLER MATTHIAS
Published: June 2005

We consider financial markets with agents exposed to an external source of risk which cannot be hedged through investments on the capital market alone. The sources of risk we think of may be weather and climate. Therefore we face a typical example of an incomplete financial market. We design a model of a market on which the external risk becomes tradable. In a first step we complete the market by introducing an extra security which valuates the external risk through a process parameter describing its market price. If this parameter is fixed, risk has a price and every agent can maximize the expected exponential utility with individual risk aversion obtained from his risk exposure on the one hand and his investment into the financial market consisting of an exogenous set of stocks and the insurance asset on the other hand. In the second step, the market price of risk parameter has to be determined by a partial equilibrium condition which just expresses the fact that in equilibrium the market is cleared of the second security. This choice of market price of risk is performed in the framework of nonlinear backwards stochastic differential equations.
A MEAN-VARIANCE-SKEWNESS MODEL: ALGORITHM AND APPLICATIONS
Authors: KONNO HIROSHI , YAMAMOTO REI
Published: June 2005

We will show that a mean-variance-skewness portfolio optimization model, a direct extension of the classical mean-variance model can be solved exactly and fast by using the state-of-the-art integer programming approach. This implies that we can now calculate a portfolio with maximal expected utility for any decreasing risk averse utility function.

Also, we will show that this model can be used as a practical tool for constructing a portfolio when the asset returns follow skewed distribution. As an example, we apply this model to construct an index plus alpha portfolio.
FIRST PASSAGE TIMES FOR RISK-TRACKING PROXIES
Authors: VAUGIRARD VICTOR
Published: June 2005

This paper determines first passage time distributions with a two-fold emphasis. The focus is first set on interest rate randomness. It derives a closed-form solution in the case of moving boundaries, indexed on risk-free bonds, and where interest rates obey mean-reverting processes and underlyings follow lognormal diffusion processes. It turns next to the underlyings, which may not be exchange-traded and whose dynamics obey jump-diffusion processes. It builds an equilibrium valuation framework and determines the rational-expectations equilibrium price of digital options. As those underlyings may be risk-tracking indices, the article can be applied to pricing insurance-linked securities, such as catastrophe bonds.
COULD SHORT SELLING MAKE FINANCIAL MARKETS TUMBLE?
Authors: VITTING ANDERSEN JØRGEN
Published: June 2005

It is suggested to consider long term trends of financial markets as a growth phenomenon. The question is what conditions are needed for a long term sustainable growth or contraction in a financial market? The paper discusses the role of traditional market players of long only mutual funds versus hedge funds which take both short and long positions. It will be argued that financial markets since their very origins and only till very recently, have been in a state of "broken symmetry" which favored long term growth instead of contraction. The reason for this "broken symmetry" in a long term "bull phase" is the historical almost complete dominance by long only players in financial markets. Only with the recent arrival of investors that take up short positions is the symmetry slowly being restored, with the implications, as will be argued, of an increased probability for lasting decline of the markets, i.e., appearance of a long term "bear phase". Recent short trade data of the Nasdaq Composite index show an increase in the short activity prior to or at the same time as dips in the market, and reveal an steady increase in short trading activity, reaching levels never seen before.
DELAY POPULATION DYNAMICS AND ENVIRONMENTAL NOISE
Authors: MAO XUERONG
Published: June 2005

In this paper we review our recent research on stochastic delay population dynamics. The main aim is to reveal that a different type of environmental noise has a different effect on delay population systems.
ON HALANAY-TYPE ANALYSIS OF EXPONENTIAL STABILITY FOR THE θ-MARUYAMA METHOD FOR STOCHASTIC DELAY DIFFERENTIAL EQUATIONS
Authors: BAKER CHRISTOPHER T. H. , BUCKWAR EVELYN
Published: June 2005

Using an approach that has its origins in work of Halanay, we consider stability in mean square of numerical solutions obtained from the θ-Maruyama discretization of a test stochastic delay differential equation [Formula: see text] interpreted in the Itô sense, where W(t) denotes a Wiener process. We focus on demonstrating that we may use techniques advanced in a recent report by Baker and Buckwar to obtain criteria for asymptotic and exponential stability, in mean square, for the solutions of the recurrence [Formula: see text]
DECAY AND GROWTH RATES OF SOLUTIONS OF SCALAR STOCHASTIC DELAY DIFFERENTIAL EQUATIONS WITH UNBOUNDED DELAY AND STATE DEPENDENT NOISE
Authors: APPLEBY JOHN A. D.
Published: June 2005

This paper studies the growth and decay rates of solutions of scalar stochastic delay differential equations of Itô type. The equations studied have a linear drift which contains an unbounded delay term, and a nonlinear diffusion term, which depends on the current state only. We show that when the nonlinearity at zero or infinity is sufficiently weak, the same non-exponential decay and growth rates found in the corresponding underlying linear deterministic equation are recovered, in an almost sure sense.
GENERAL METHOD OF LYAPUNOV FUNCTIONALS CONSTRUCTION IN STABILITY INVESTIGATIONS OF NONLINEAR STOCHASTIC DIFFERENCE EQUATIONS WITH CONTINUOUS TIME
Authors: SHAIKHET LEONID
Published: June 2005

The general method of Lyapunov functionals construction has been developed during the last decade for stability investigations of stochastic differential equations with after-effect and stochastic difference equations. After some modification of the basic Lyapunov type theorem this method was successfully used also for difference Volterra equations with continuous time. The latter often appear as useful mathematical models. Here this method is used for a stability investigation of some nonlinear stochastic difference equation with continuous time.
A TWO-STATE MODEL FOR NOISE-INDUCED RESONANCE IN BISTABLE SYSTEMS WITH DELAY
Authors: FISCHER MARKUS , IMKELLER PETER
Published: June 2005

We discuss a simplified model for a symmetric bistable system with memory or delay, the reference model, which in the presence of noise, exhibits a phenomenon similar to what is known as stochastic resonance. The reference model is given by a one-dimensional parametrized stochastic differential equation with point delay, basic properties whereof we check.

With the aim of capturing the effective dynamics and, in particular, the resonance-like behavior of the reference model, we construct a simplified or reduced model, the two-state model, first in discrete time, then in the limit of discrete time tending to continuous time. The main advantage of the reduced model is that it enables us to explicitly calculate the distribution of residence times which in turn can be used to characterize the phenomenon of noise-induced resonance.

Drawing on what has been proposed in the physics literature, we outline a heuristic method for establishing the link between the two-state model and the reference model. The resonance characteristics developed for the reduced model can thus be applied to the original model.
OPTIMAL STOPPING WITH DELAYED INFORMATION
Authors: ØKSENDAL BERNT
Published: June 2005

We study a general optimal stopping problem for a strong Markov process in the case when there is a time lag δ > 0 from the time τ when the decision to stop is taken (a stopping time) to the time τ + δ when the system actually stops. Equivalently, we impose the constraint that the admissible times for stopping are stopping (Markov) times with respect to the delayed flow of information. It is shown that such a problem can be reduced to a classical optimal stopping problem by a simple transformation. The results are applied:

(i) to find the optimal time to sell an asset

(ii) to solve an optimal resource extraction problem,

in both cases under delayed information flow.
INFERENCE OF SYSTEMS WITH DELAY AND APPLICATIONS TO CARDIOVASCULAR DYNAMICS
Authors: BANDRIVSKYY A. , LUCHINSKY D. G. , McCLINTOCK P. V. E. , SMELYANSKIY V. N. , STEFANOVSKA A.
Published: June 2005

A Bayesian inference technique, able to encompass stochastic nonlinear systems, is described. It is applicable to differential equations with delay and enables values of model parameters, delay, and noise intensity to be inferred from measured time series. The procedure is demonstrated on a very simple one-dimensional model system, and then applied to inference of parameters in the Mackey-Glass model of the respiratory control system based on measurements of ventilation in a healthy subject. It is concluded that the technique offers a promising tool for investigating cardiovascular interactions.
TIME SERIES ANALYSIS OF MULTIVARIATE TIME-DELAYED SYSTEMS WITH NOISE: APPLICATIONS TO LASER PHYSICS AND HUMAN MOVEMENT
Authors: FRANK T. D. , FRIEDRICH R. , BEEK P. J.
Published: June 2005

A data analysis method is proposed to reconstruct evolution equations of stochastic systems with time-delayed feedback from experimental time series. Multivariate systems involving noise sources with arbitrary correlation times are considered.
EXPONENTIAL GROWTH RATES FOR STOCHASTIC DELAY DIFFERENTIAL EQUATIONS
Authors: SCHEUTZOW MICHAEL
Published: June 2005

In this survey, we provide some tools to obtain estimates for the almost sure exponential growth rate of a stochastic delay differential equation (sdde) which fixes zero. In particular, we are interested in determining whether the solutions of a given sdde are exponentially stable (i.e. have a negative exponential growth rate) or not. We focus on equations without drift, which are a good testground to assess if a method is powerful enough to discriminate between stability and instability when a certain parameter (e.g. noise intensity) varies. The most powerful tool we provide is the method of Lyapunov functionals which is used to obtain upper bounds for p-th moment exponents for small (positive and negative) values of p.
NUMERICAL INVESTIGATION OF D-BIFURCATIONS FOR A STOCHASTIC DELAY LOGISTIC EQUATION
Authors: FORD NEVILLE J. , NORTON STEWART J.
Published: June 2005

This paper explores the use of numerical (approximation) methods in the detection of changes in the dynamical behaviour of solutions to parameter-dependent stochastic delay differential equations. We focus on the use of approximations to Lyapunov exponents. Using three numerical methods we begin to describe the probability distributions of the local approximate Lyapunov exponents and we use this information to enable us to predict values of the parameters at which solutions bifurcate. We conclude the paper by reviewing some of the potential pitfalls of using numerical simulations to detect the dynamical behaviour of the solutions to stochastic delay differential equations.
STABILITY OF STOCHASTIC SYSTEMS WITH MEMORY
Authors: POTAPOV V. D.
Published: June 2005

Many processes in physics, biology, ecology, mechanics etc. can be modeled by Volterra integro-differential equations (VIDEs) with "fading memory". Often the behaviour of corresponding systems is perturbed by random noises. One of the main problems for the theory of stochastic Volterra integro-differential equations (SVIDEs) is connected with their stability. The present paper is devoted to the numerical solution of the stability problem for linear SVIDEs. The method is based on the statistical simulation of input random wide-band stationary processes, which are assumed in the form of "colored" noises. For each realization the numerical solution of VIDEs is found. The conclusion about the stability of the considered system SVIDE with respect to statistical moments is made on the basis of Liapunov exponents, which are calculated for statistical moments of the solution.
SELF-ASSEMBLED INDIUM-ARSENIDE ELONGATED NANOSTRUCTURE GROWN BY MOLECULAR BEAM EPITAXY
Authors: SURAPRAPAPICH S. , THAINOI S. , LALIEW C. , KANJANACHUCHAI S. , PANYAKEOW S.
Published: June 2005

Self-assembled InAs elongated nanostructures were fabricated by continuous processing steps, starting from self-assembling of quantum dots, thin capping over the quantum dots to induce an anisotropic strain field, and to anneal the quantum dots in the molecular-beam-epitaxy machine. In-situ RHEED observations at each processing step were studied and confirmed by ex-situ AFM images of the surface morphology. The elongated nanostructures were demonstrated tobe templates for chains of uniform quantum dots.
STEP CURRENT ELECTRODEPOSITION OF NANOCRYSTALLINE Ni80Fe20/Cu COMPOSITE WIRES
Authors: LI X. P. , ZHAO Z. J. , SEET H. L. , LIM P. L. , LEE K. S.
Published: June 2005

A new method called Step Current Electrodeposition (SCE) is proposed for the nanocrystalline deposition of high uniformity large coating thickness of Ni80Fe20/Cu composite wires. The hysteresis loops of the composite wires, developed by SCE and conventional plating, were measured using an inductance method and a magneto-impedance (MI) experimental setup, and the magnetic properties of the composite wires in terms of the hysteresis loops and the magneto-impedance effect were measured. The results showed that the experimental results obtained, which was in the trend of increasing GMI with increasing coating thickness till an optimum, agree well with the simulated results as found in the literature.1
InAs SELF-ORGANIZED QUANTUM DOTS GROWN BY MOLECULAR BEAM EPITAXY USING A "NUCLEATION-AUGMENTED" METHOD
Authors: CHIA CHING KEAN , CHUA SOO JIN , MIAO ZHONGLIN , CHYE YEW HEE
Published: June 2005

Photoluminescence (PL) measurements performed in a series of InAs self-assembled quantum dot (QD) structures grown by molecular beam epitaxy (MBE) on GaAs (100) substrates using a two-stage "nucleation-augmented" growth method show that an InAs QD "nucleation" layer grown at a fast growth rate, followed by a slowly grown InAs "augmented" layer, dramatically increases the dot density and improves the PL intensity. Besides red-shift in peak wavelength, the PL intensity was found to increase as the growth rate of the InAs augmented layer was reduced. The increased PL intensity was due to a higher dot density arising from the nucleation layer and an improved optical quality caused by the growth interruption in the augmented layer.
NANOSIZE POWDERS OF SILVER-DOPED SODIUM COBALT OXIDE SYNTHESIZED BY POLYMERIZED COMPLEX METHOD
Authors: SEETAWAN TOSAWAT , AMORNKITBAMRUNG VITTAYA , BURINPRAKHON THANUSIT , MAENSIRI SANTI
Published: June 2005

Nanosized powders used for the preparation of bulk Na1.5Co2O4 and Ag -doped Na1.5Co2O4 nanosized crystalline grains were synthesized by the polymerized complex (PC) method. X-ray diffraction analysis revealed that the nondoped and Ag -doped PC products were composed of Co3O4 and Na2CO3 phases. After a subsequent calcination at 800°C, the nondoped PC product was converted to powder of single phase γ- NaxCo2O4 , whereas the Ag -doped PC products remained as mixed phases of Co3O4 and Na2CO3 and Ag2O with a small trace of γ- NaxCo2O4 . SEM and TEM investigations showed that all the calcined products were powders of about 200–500 nm particle size.
A METHOD OF EXTRACTING AND EVALUATING GOOD AND BAD REPUTATIONS FOR NATURAL LANGUAGE EXPRESSIONS
Authors: FUKETA MASAO , KADOYA YUKI , ATLAM ELSAYED , KUNIKATA TSUTOMU , MORITA KAZUHIRO , KASHIJI SHINKAKU , AOE JUN-ICHI
Published: June 2005

Although a users' opinion or a live voice is a very useful information for text mining of the business, it is difficult to extract good and bad reputations of users from texts written in natural language. The good and bad reputations discussed here depend on users' claims, interests and demands. This paper presents a method of determining these reputations in commodity review sentences. Multi-attribute rule is introduced to extract the reputations from sentences, and four-stage-rules are defined in order to evaluate good and bad reputations step by step. A deterministic multi-attribute pattern matching algorithm is utilized to determine the reputations efficiently.

From simulation results for 2,240 review comments, it is verified that the multi-attribute pattern matching algorithm is 63.1 times faster than the Aho and Corasick method. The precision and recall of extracted reputations for each commodity are 94% and 93% respectively. Moreover, the precision and recall of the resulting reputations for each rule are 95% and 95% respectively.
ADVERTISING DATA ANALYSIS USING ROUGH SETS MODEL
Authors: KUMAR ASHWANI , AGRAWAL D. P. , JOSHI S. D.
Published: June 2005

This study explores the use of rough-set methods for marketing decision support systems in the retail business. A tutorial presentation of Rough Set Data Analysis (RSDA) in the context of knowledge discovery from time series databases is given. We show how an RSDA model can be used to develop a marketing decision support system which can capture the complex relationships between marketing factors, such as advertising and promotion, and the total impact on sales levels in order to find influential advertising strategies. This information is used by the business manager to make faster and better strategy decisions for the business to survive in the rapidly changing and competitive environments. The data set used for RSDA application example contains weekly investments in different media categories: TV, radio, cinema, morning press, evening press, popular press, special interest press, and outdoor posters; for seven makes of cars in the Swedish market.
A FLEXIBLE AUTHENTICATION AND AUTHORIZATION SCHEME FOR A LEARNER INFORMATION MANAGEMENT WEB SERVICE
Authors: CUMMINGS C. STEVEN , SHI HONGCHI , SHANG YI , CHEN SU-SHING
Published: June 2005

As many software systems migrate their component communication to the web service paradigm, security becomes an immediate concern. Many existing solutions cannot handle complex situations involving the user, session, application, and any number of XML inter-related documents. The learner information management web service we develop for an e-learning environment has to control access of inter-related XML documents representing different roles of users in the e-learning environment. In this paper, we present an authentication and authorization model for web services that provides access control of inter-related XML documents. This scheme works especially well when the documents that will be operated on are organized in hierarchical structures, like the collections in a native XML database.
EMPIRICAL STUDY ON INFORMATION AND COMMUNICATION TECHNOLOGY AND YOUTH IN A DEVELOPING COUNTRY: NIGERIA AS A CASE
Authors: IDOWU A. O. , IDOWU PETER ADEBAYO , ADAGUNODO E. R.
Published: June 2005

The phenomenal growth of information and communication technology (ICT) especially the Internet has affected youths in developed and developing countries alike. Although progressing at a slower rate in developing countries than in any other parts of the world, Internet connectivity is also transforming the face of Africa.

This paper presents a study that examines what Nigerian youths use Internet for and which of the Internet use has adverse effect on the youth's social life. It reveals that majority of youths use Internet for e-mail, making use of Yahoo followed by Hotmail, and the study also reveals that over 50% of youths interviewed visit pornographic sites.
Oxygen Reduction Reaction on Pt and Pt-Bimetallic Electrodes Covered by CO : Mechanism of the Air Bleed Effect with Reformate
Authors: Stamenkovic V. , Grgur B. N. , Ross P. N. , Markovic N. M.
Published: June 2005

The oxygen reduction reaction (ORR) has been studied on CO-covered Pt(111), Pt(110), Pt-poly, Pt-Ru,

Pt

3

Sn
(
111
)
,

and

Pt

3

Sn
(
110
)

electrodes in 0.5 M

H

2

SO

4

solution at temperatures varying between 298 and 333 K using the rotating ring-disk electrode (RRDE) method. The RRDE measurements showed that even during

O

2

reduction a substantial amount

(
≈
40
%

of saturation) of CO still remains on all surfaces. Only a very small fraction of consumed

O

2

is used for CO oxidation, while the major fraction reacts via the competing ORR, producing

H

2

O

2

.

The

H

2

O

2

yield is strongly dependent on the fractional coverage by adsorbed CO, the surface structure, and the composition of the electrode. While at

Θ

CO

>
0.5
 
monolayer

(ML) the

H

2

O

2

yield is very high (depending on the structure/nature of the electrode ca. 60-100%), when

Θ

CO

falls to its steady-state value of

≈
0.4
ML
,

the

H

2

O

2

yield is almost the same as on the respective CO-free surfaces. Although the production of peroxide on some electrodes is rather low at 333 K (e.g., 5% on PtRu and 10% on Pt-poly), the practical consequences of the

H

2

O

2

production can be significant; e.g.,

H

2

O

2

may cause an enhanced long-term degradation of the membrane. © 2004 The Electrochemical Society. All rights reserved.
Adhesion-dependent activation of CaMKII and regulation of ERK activation in vascular smooth muscle
Authors: Lu Katherine Kun , Armstrong Shayn E. , Ginnan Roman , Singer Harold A.
Published: June 2005

Cell adhesion-dependent activation of ERK1/2 has been linked functionally to focal adhesion dynamics. We previously reported that in adherent vascular smooth muscle (VSM) cells, CaMKII mediates ERK1/2 activation in response to Ca2+-mobilizing stimuli. In the present study, we tested whether CaMKII regulates ERK1/2 signaling in response to VSM cell adhesion. Using an antibody that specifically recognizes CaMKII autophosphorylated on Thr287, we determined that CaMKII is rapidly activated (within 1 min) after the adherence of cells on multiple ECM substrates. Activation of CaMKII on fibronectin was unaffected in cells overexpressing focal adhesion kinase (FAK)-related nonkinase (FRNK), an endogenous inhibitor of FAK. Furthermore, CaMKII was rapidly and robustly activated in VSM cells plated on poly-l-lysine. These results suggest that adhesion-dependent CaMKII activation is integrin independent. Adhesion-dependent FAK activation on fibronectin was not affected in cells treated with the selective CaMKII inhibitor KN-93 (30 μM) or in cells in which the expression of CaMKII with small interfering RNA (siRNA) was suppressed, although tyrosine phosphorylation of paxillin was inhibited in CaMKII-δ2-suppressed cells. Sustained ERK1/2 activation that was dependent on FAK activation (inhibited by FRNK) was also attenuated by CaMKII inhibition or siRNA-mediated gene silencing. Rapid ERK1/2 activation that preceded FAK and paxillin activation was detected upon VSM cell adhesion to poly-l-lysine, and this response was inhibited by CaMKII gene silencing. These results indicate that integrin-independent CaMKII activation is an early signal during VSM cell adhesion that positively modulates ERK1/2 signaling through FAK-dependent and FAK-independent mechanisms.