bluuebunny/crossref_metadata_2025 huggingface dataset:
THE USE OF FARADAY INSTABILITY TO PRODUCE DEFINED TOPOLOGICAL ORGANIZATION IN CULTURES OF MAMMALIAN CELLS
Authors: TAKAGI SEIJI , KRINSKY VALENTIN , PUMIR ALAIN , FRELIN CHRISTIAN
Published: October 2002

Pattern formation occurs spontaneously in endothelial cell cultures, leading to the formation of capillary networks, which eventually grow to form blood vessels. This phenomenon occurs on a time scale of a few days.

We show here that patterns can also be induced on a much shorter time scale, by using the Faraday hydrodynamic instability, resulting from an oscillatory motion of the container. Close to the threshold of instability, the patterns observed are very sharp concentric rings or stripes. The patterns can be induced only inside a very narrow time window, ~ 5 min. Cells attachment then develops, and pattern formation can no longer be induced. The time window for pattern formation was diminished by favoring cell attachment, for instance by treating culture dishes with cationic macromolecules, such as poly-L-Lysine. It was increased by cooling the cells to 18°C, or by a prolonged exposure of the cells to trypsin, which is known to digest adhesion molecules.

The Faraday instability leads to a method to characterize cell attachment. It also permits the production of heterogeneous cultures with several cell types, with a well controlled heterogeneity. This can be used to study heterotypic cell interactions in vitro.
MATHEMATICAL MODELS FOR CELL-MATRIX INTERACTIONS DURING DERMAL WOUND HEALING
Authors: MAINI P. K. , OLSEN L. , SHERRATT J. A.
Published: October 2002

This paper contains a review of our recent work on the mathematical modeling of cell interaction with extracellular matrix components during the process of dermal wound healing. The models are of partial differential equation type and allow us to investigate in detail how various mechanochemical effects may be responsible for certain wound healing disorders such as fibrocontractive and fibroproliferative diseases. We also present a model for wound healing angiogenesis. The latter has several features in common with angiogenesis during cancer tumour growth and spread so a deeper understanding of the phenomenon in the context of wound healing may also help in the treatment of certain cancers.
EXPONENT OF PERIODICITY OF WORD EQUATIONS IN FIXED DIMENSION IS POLYNOMIAL
Authors: GUTIÉRREZ CLAUDIO
Published: October 2002

The exponent of periodicity is a key parameter used in all currently known algorithms for solving word equations. A lower bound for it is 2c|E|, where |E| is the length of the equation E. We prove that in fixed dimension, i.e. when the variables belong to a fixed set V, the exponent of periodicity can be bound by a polynomial p(|E|) of degree no more than thrice the size of the set V.
A SHELL CLASSIFICATION BY INTERPOLATION
Authors: BAIOCCHI C. , LOVADINA C.
Published: October 2002

The shell problem and its asymptotic are investigated. A connection between the asymptotic behavior and real interpolation theory is established. Thus, a detailed study of the cases when neither the bending energy nor the membrane energy dominate is provided. An application to a cylindrical shell is also detailed. Although only the Koiter shells have been considered, the same procedure can be used for other models, such as Naghdi's one, for example.
LIMIT OF A COLLECTION OF DYNAMICAL SYSTEMS: AN APPLICATION TO MODELING THE FLOW OF TRAFFIC
Authors: DARBHA SWAROOP , RAJAGOPAL K. R.
Published: October 2002

The flow of traffic is usually described using a continuum approach as that of a compressible fluid, a statistical approach via the kinetic theory of gases or cellular automata models. These approaches are not suitable for modeling dynamical systems such as traffic. While such systems are large collections, they are not large enough to be treated as a continuum. We provide a rationale for why they cannot be appropriately described using a continuum model, the kinetic theory of gases, or by appealing to cellular automata models. As an alternative, we develop a discrete dynamical systems approach that is particularly well suited to describe the dynamics of large systems such as traffic.
ON THE INVISCID AND NON-RESISTIVE LIMIT FOR THE EQUATIONS OF INCOMPRESSIBLE MAGNETOHYDRODYNAMICS
Authors: DÍAZ J. I. , LERENA M. B.
Published: October 2002

We prove the convergence of the solutions for the incompressible homogeneous magnetohydrodynamics (MHD) system to the solutions to ideal MHD one in the inviscid and non-resistive limit, detailing the explicit convergence rates. For this study we consider a fluid occupying the whole space ℝ3 and we assume that the viscosity effects in this fluid can be described by two different operators: the usual Laplacian operator affected by the inverse of the Reynolds number or by a viscosity operator introduced by S. I. Braginskii in 1965.
COMPARISONS, BY MODELS, OF SOME BASIC MECHANISMS ACTING ON THE DYNAMICS OF THE ZOOPLANKTON-TOXIC PHYTOPLANKTON SYSTEM
Authors: EL ABDLLAOUI A. , CHATTOPADHYAY J. , ARINO OVIDE
Published: October 2002

In this paper, classes of mathematical models of phytoplankton–zooplankton systems with toxic phytoplankton are proposed and analysed.

We investigate various situations, by changing the uptake function, the mortality of the zooplankton or the toxin liberation process, and we compare the corresponding dynamics.

We show notably that a stable oscillatory regime (after a Hopf bifurcation) can only be observed if the uptake function is nonlinear.
TOWARDS MATHEMATICAL MODELS IN PSYCHOLOGY: A STOCHASTIC DESCRIPTION OF HUMAN FEELINGS
Authors: CARBONARO BRUNO , SERRA NICOLA
Published: October 2002

The paper deals with a mathematical description of human feelings (such as hostility, or indifference or love) toward other human beings. The discussion is carried out in a somewhat simplified scheme, by describing the psychological state of each individual by only one state variable, conceived as a kind of "measure" of its feelings. This is, however, to be meant as simply a first step towards a more comprehensive description of human psychology, taking into account character, tastes and possibly past experiences of each individual involved in a social relation. For the simplified description here developed, we propose a system of nonlinear integro-differential stochastic equations, aiming at giving at least a probabilistic forecast of the evolution of reciprocal feeling of two relating individuals. Thus, the solution of the system will be a couple of probability density functions, for which we present a short preliminary discussion of existence and uniqueness as well as of stability and the possible occurrence of strong instability effects. A number of numerical simulations are presented to test the significance of the model and some ways to extend the scheme, by introducing a number of additional external as well as internal parameters that can reasonably be assumed to influence the reciprocal feelings, are suggested and discussed, with special attention to the concept of stochastic "constitutive laws" for the feelings.
EXISTENCE OF SOLUTIONS TO A THERMO-VISCOELASTIC CONTACT PROBLEM WITH COULOMB FRICTION
Authors: ECK C.
Published: October 2002

A thermo-viscoelastic contact problem with Coulomb friction is studied. The model involves a temperature-dependent heat conductivity with moderate growth in order to control the rapidly growing mixed terms as e.g. the heat generated by friction or by viscous deformation. The contact condition is formulated in velocities. The existence of a solution is proved by an approximation of the problem in several steps involving a penalty-approximation and a smoothing of the friction law. The solvability of the approximate problem is proved by the Galerkin method. A priori estimates uniform with respect to all approximation parameters make it possible to pass to the original problem. These estimates are based on a regularity result for the contact problem without heat transfer.
CRITICAL NONLINEAR SCHRÖDINGER EQUATIONS WITH AND WITHOUT HARMONIC POTENTIAL
Authors: CARLES RÉMI
Published: October 2002

We use a change of variables that turns the critical nonlinear Schrödinger equation into the critical nonlinear Schrödinger equation with isotropic harmonic potential, in any space dimension. This change of variables is isometric on L2, and bijective on some time intervals. Using the known results for the critical nonlinear Schrödinger equation, this provides information for the properties of Bose–Einstein condensate in space dimension one and two. We discuss in particular the wave collapse phenomenon.
FLORAL ATTRACTIVENESS AND REWARDS AFFECT RESILIENCE OF HOST-POLLINATOR SYSTEMS: A GENETIC MODEL
Authors: MEDAN DIEGO , BARTOLONI NORBERTO
Published: October 2002

A genetic model was designed to depict what the resilience of host-pollinator interactions may be according to well known genetic rules and assuming an underlying genetic basis for (a) the attraction that flowers exert on pollinators, and (b) the fitness gain by the pollinator from visiting a flower. We explore the possible trajectories that a plant-pollinator system describes under certain bound conditions determined by a whole complex of attractiveness and reward scores. Such scores represent genetic relations between two diallelic loci assumed to control both traits. To see how the system would behave over time we created eight different scenarios, differing in the orientation they impose on the system. Half of these situations are of a reinforcing type (indicating a similar input both for attractiveness and rewards) and the remaining ones are conflicting (indicating opposite inputs). A numerical simulation was carried over seventy-five generations starting from Hardy–Weinberg equilibrium populations. We detected some general behavioral patterns in the final structure of frequencies. One of these may be viewed as a resilient type of structure (i.e., without memory of the initial population frequencies) which we hypothesize, may reflect the typical attraction-reward structure generally observed in nature. Another pattern is characterized by a pronounced lose of heterozygotes in the final structure, caused by the fixation of the most attractive phenotypes at the expense of the least attracting ones, independently of the pollinator genotype.
A FORMALISM FOR REPRESENTING AND REASONING WITH LINGUISTIC INFORMATION
Authors: CAO TRU H.
Published: October 2002

Conceptual graphs and fuzzy logic are two logical formalisms that emphasize the target of natural language, where conceptual graphs provide a structure of formulas close to that of natural language sentences while fuzzy logic provides a methodology for computing with words. This paper proposes fuzzy conceptual graphs as a knowledge representation language that combines the advantages of both the two formalisms for artificial intelligence approaching human expression and reasoning. Firstly, the conceptual graph language is extended with functional relation types for representing functional dependency, and conjunctive types for joining concepts and relations. Then fuzzy conceptual graphs are formulated as a generalization of conceptual graphs where fuzzy types and fuzzy attribute-values are used in place of crisp types and crisp attribute-values. Projection and join as basic operations for reasoning on fuzzy conceptual graphs are defined, taking into account the semantics of fuzzy set-based values.
DIFFERENTIAL INTERFERENCE CONTRAST FOR X-RAY MICROSCOPY: FABRICATION AND CHARACTERIZATION OF TWIN ZONE PLATE OPTICS
Authors: DI FABRIZIO ENZO , KAULICH BURKHARD , WILHEIN THOMAS , SUSINI JEAN
Published: October 2002

A novel X-ray technique for converting the phase information of weakly absorbing specimen into strong image contrast similar to Nomarski differential interference contrast (DIC) is presented. DIC for X-rays is accomplished by the fabrication of a novel X-ray optic (TZP) consisting of two zone plates (ZPs) on both sides of the same substrate, laterally shifted by about one outermost zone width. The feasibility of DIC for X-rays was proven at the ID 21 X-ray microscopy beamline at the ESRF using a full-field imaging microscope and a scanning transmission X-ray microscope, which were operated at 4 keV photon energy. In both microscopes, we observe a tremendous contrast enhancement of up to a factor of 25. Though first experiments were carried out at 4 keV photon energy, this X-ray DIC technique can be adapted to any photon energy where ZPs with appropriate parameters and imaging performance can be designed and manufactured.
VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES
Authors: ZHOU WEIDONG , SECCOMBE D. P. , CHIM R. Y. L. , TUCKETT R. P.
Published: October 2002

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.
THICKNESS DEPENDENCE OF PHOTOEMISSION SPECTRA IN ZINC-BLENDE CrAs
Authors: MIZUGUCHI M. , ONO K. , OSHIMA M. , OKABAYASHI J. , AKINAGA H. , MANAGO T. , SHIRAI M.
Published: October 2002

The electronic structure of CrAs thin films with nominal thicknesses of 2 nm and 30 nm were studied by angle-resolved photoemission spectroscopy using synchrotron radiation. The CrAs film of 2 nm is expected to form a zinc-blende phase which is predicted to have a half-metallic band structure by theoretical calculation. On the other hand, it is considered that the CrAs film of 30 nm is a polycrystalline compound judging from reflection high-energy electron diffraction patterns. Different valence-band photoemission spectra were obtained for the two films. The photoemission spectra of the CrAs film of 30 nm showed no band dispersion, whereas a band dispersion was observed in that of the CrAs film with the nominal thickness of 2 nm.
Mn 3p–3d RESONANT INVERSE-PHOTOEMISSION SPECTROSCOPY OF NiAs-TYPE MnTe
Authors: SATO H. , KANI Y. , UEDA Y. , NAGASAKI F. , SENBA S. , NAMATAME H. , TANIGUCHI M.
Published: October 2002

Resonant inverse-photoemission spectra of NiAs-type MnTe have been measured with the tunable photon energy mode at kinetic energies of incident electrons (Ek) in the Mn 3p–3d excitation region. The peak structure at 2.9 eV above the valence-band maximum (VBM) is resonantly enhanced at Ek = 50 eV and is attributed to transitions to d 6 final states with 5 E and 5 T 2 symmetries. The broad structure around 12 eV above the VBM in the spectrum at Ek = 46.5 eV and a shoulder on the higher energy side of the main peak at 2.9 eV in the spectrum at Ek = 50 eV is assigned to [Formula: see text] final states and d6 final states with 3Γ symmetries, respectively, where [Formula: see text] stands for a ligand hole and Γ an irreducible representation.
X-RAY ABSORPTION EVIDENCE FOR THE BACK-DONATION IN IRON CYANIDE COMPLEXES
Authors: VINOGRADOV A. S. , PREOBRAJENSKI A. B. , KRASNIKOV S. A. , CHASSÉ T. , SZARGAN R. , KNOP-GERICKE A. , SCHLÖGL R. , BRESSLER P.
Published: October 2002

High-resolution, uniformly calibrated Fe 2p 3/2 absorption spectra of various Fe(II) and Fe(III) compounds with the metal atom octahedrally coordinated to atomic and molecular ligands are analyzed expecting changes in the absorption spectra due to differences in the formal valence state and in the character of the chemical bond. Particular attention is given to revealing spectral characteristics of the 3d π–2π(π*) charge transfer (π-back-donation effect) between the iron atom and cyanide ligands.
A PEEM STUDY OF SMALL AGGLOMERATES OF COLLOIDAL IRON OXIDE NANOCRYSTALS
Authors: NOLTING F. , LÜNING J. , ROCKENBERGER J. , HU J. , ALIVISATOS A. P.
Published: October 2002

A common limitation in nanostructure research is often the requirement to perform experiments on ensembles of nanoparticles, therefore averaging over inherent distributions with respect to particle size and shape, chemical composition, crystallinity and defect structure. This limitation can be overcome by studying the properties of a single nanostructure individually, which will allow one to truly correlate scaling laws of material properties with changes in size. Here we report the first experiments to explore the feasibility of spectromicroscopy using a photoemission electron microscope (PEEM) to record the X-ray absorption spectra of single nanocrystals. Colloidal iron oxide nanocrystals with an average diameter and standard deviation of 13 nm and 2 nm, respectively, were deposited on graphite (HOPG) forming small islands of agglomerated γ- Fe 2 O 3 nanocrystals (4–30 particles) as determined by scanning electron microscopy. Spatially resolved soft X-ray absorption spectra at the Fe L 3,2 edges of these individual islands were recorded with the PEEM2 instrument of the Advanced Light Source (ALS).
MEASUREMENT OF THE SECOND-ORDER COHERENCE OF SYNCHROTRON RADIATION IN THE VUV REGION
Authors: SHIOZAWA HIDETSUGU , OBU KENJI , LEE CHOL , TAKAYAMA YASUHIRO , MIYAHARA TSUNEAKI , TAI RENZHONG , NAMIKAWA KAZUMICHI , ANDO MASAMI , YAMAMOTO SHIGERU , URAKAWA JUNJI , HAYANO HITOSHI
Published: October 2002

We have performed the two-photon correlation measurement of synchrotron radiation in the VUV region to characterize the photon statistics of the light. The explicit bunching effect of the second-order coherence is observed, which implies that synchrotron radiation has a chaotic nature. We also estimate the electron beam emittance of a stored beam. The two-photon correlation measurement will be utilized to diagnose the storage ring and to characterize the coherence properties of X-ray free electron laser in the future.
POLARIZATION DEPENDENCE OF RESONANT SOFT X-RAY EMISSION SPECTRA IN Ce COMPOUNDS
Authors: WATANABE M. , HARADA Y. , NAKAZAWA M. , ISHIWATA Y. , EGUCHI R. , TAKEUCHI T. , KOTANI A. , SHIN S.
Published: October 2002

The electronic structures of Ce compounds have been investigated by means of resonant soft X-ray emission spectroscopy (RXES) excited at resonant energy range of Ce 3d → 4f absorption. Polarization dependence of the RXES shows information on concerning electronic states. In CeO 2, the Ce 4f → 3d RXES spectra are interpreted as electronic structures hybridized between 4f0 and [Formula: see text] states. Peaks appearing in the spectra are attributed to bonding, nonbonding, and antibonding states between those states, while the spectra of CeRh 3 cannot be explained by only using the hybridization between 4f0 and [Formula: see text] states. The spectra have large broad Raman peak, especially when the excitation photon energy is set at satellite of Ce 3d → 4f absorption. We attribute the origin of the broad Raman peak to hybridization states involving electron–hole pairs.
PEIERLS FLUCTUATIONS IN THE ELECTRON SYSTEM OF A QUASI-ONE-DIMENSIONAL SOLID
Authors: SCHÄFER J. , CLAESSEN R. , ROTENBERG ELI , KEVAN S. D. , BLAHA P. , THORNE R. E.
Published: October 2002

The physics of the Peierls compound NbSe3 is elucidated by mapping of the electron bands obtained from angle-resolved photoemission. We present experimental data on the Fermi level crossing responsible for the charge density wave along the one-dimensional axis. The data are consistent with a density functional calculation of the Fermi surfaces. The instability with periodicity q = 0.44 Å-1 induces a backfolding of the electron bands in the nominally metallic state high above the critical temperature of 145 K.
Ce4f STATES IN CePd2Si2 AND CeNi2Si2 INVESTIGATED BY RESONANT PHOTOEMISSION SPECTROSCOPY
Authors: MIMURA K. , OKABAYASHI Y. , MIZOHATA H. , SAKIYAMA D. , SAKAI O. , HUO D. , SAKURAI J. , TAGUCHI Y. , ICHIKAWA K. , AITA O.
Published: October 2002

Ce 4f electronic states in an antiferromagnetic Kondo compound CePd 2 Si 2 and a strong intermediate-valence compound CeNi 2 Si 2 have been investigated by means of high-resolution Ce 4d–4f resonant photoemission spectroscopy at 12 K. The relative intensity of the f5/21 to f7/21 final state in the Ce 4f spectrum for CeNi 2 Si 2 is stronger than the relative intensity for CePd 2 Si 2, indicating that the intensity of Kondo resonance scales the Kondo temperature since the Ce 4f spectrum near the Fermi level dominantly reflects the bulk component. Both Ce 4f spectra have been well fitted by the spectral calculations based on a single impurity Anderson model with consideration of the bulk and surface components. Our present calculation indicates that the model is applicable to the analyses of the Ce 4f spectra of the weakly and strongly hybridized systems.
PHOTOELECTRON SPECTRA OF SUBMONOLAYER C60F48 FILMS ON d-METAL SUBSTRATES
Authors: YU. SVETCHNIKOV N. , KOLMAKOV A. A. , STANKEVITCH V. G.
Published: October 2002

Photoemission valence band spectra of submonolayer fullerene C 60 F 48 films, evaporated in situ on d-metal foils of Au, Pt, Ta, W, Ni, were acquired under He II (40.8 eV) excitation at 300 K. Spectral structure transformations versus film thickness and substrate material were under investigation. For coverage ~ 0.5–1.0 ML C 60 F 48 the main spectral features were found to be close to those measured for thick films: with a main peak at Eb ≈ 9 eV (F2p) and a broad peak at 11.4 eV (C2p or C2s). However, a new low intensity band with Eb ≈ 1.5 eV (FWHM ≈ 1.4 eV) was found to arise at a film thickness of about 0.4–0.5 ML and to decrease beyond 1 ML. It may be attributed to a strong ion-covalent bonding between d-metal and fullerene at low coverage. For coverages exceeding 0.3 ML the spectra were found to be weakly dependent on substrate material, except for Ni, where this new band was found at Eb = 2.2 eV and the main peak at Eb = 9.7 eV .
BULK BAND GAPS IN DIVALENT HEXABORIDES: A SOFT X-RAY EMISSION STUDY
Authors: DENLINGER J. D. , GWEON G.-H. , ALLEN J. W. , BIANCHI A. D. , FISK Z.
Published: October 2002

Boron K-edge soft X-ray emission and absorption are used to address the fundamental question of whether divalent hexaborides are intrinsic semimetals or defect-doped band gap insulators. These bulk-sensitive measurements, complementary and consistent with surface-sensitive angle-resolved photoemission experiments, confirm the existence of a bulk band gap and the location of the chemical potential at the bottom of the conduction band.
FEASIBILITY OF FORMATION OF AZS (ALUMINA–ZIRCONIA–SILICA) REFRACTORY PRODUCTS WITH DIFFERENT COMPOSITION TO THE COMMERCIAL PRODUCT THROUGH X-RAY DIFFRACTION
Authors: GUZMÁN A. M. , RODRÍGUEZ P.
Published: October 2002

The AZS refractory materials with different composition to the commercial product were obtained, and the feasibility of formation of these products was studied taking like departure point the free energy of their formation. The AZS refractories were obtained by a traditional method of producing ceramic materials, the process of sintering.
PERIODIC DFT STUDY OF ISOMORPHOUS INCORPORATION OF A V ION INTO (100) AND (001) ANATASE SURFACE LAYERS
Authors: KACHUROVSKAYA NELLY A. , ZHIDOMIROV GEORGII M. , MINOT CHRISTIAN
Published: October 2002

Two models of a V2O5 catalyst supported on TiO2 are compared using DFT-GGA periodic calculations. In the first one, the energetically least favorable, a surface Ti atom of the TiO2 anatase is substituted by a V atom, leading to a V+4 ion as active site. In the second model, the Ti atom is substituted by a VOH group; pentacoordinated V+5 ions are formed at the surface. This model leads to the most stable system with a gap between the occupied band mainly localized on the oxygen ions and the vacant band mainly localized on the metal ions. For the (100) face, it is concluded that the substitutions occur with the same energies at first neighbor and second neighbor metal positions. The adsorption energies are slightly larger for the (001) face, which is more stable.
FAILURE OF THE POLYETHYLENE LINEAR OF A BIPOLAR HIP PROSTHESIS RESULTING IN DEEP DEFECT AND IMPENDING FRACTURE OF THE NECK OF THE FEMORAL STEM COMPONENT
Authors: Tsai Tsung-Ting , Hsu Robert Wen-Wei , Shih Hsin-Nung , Huang Tsung-Jen
Published: October 2002

This paper reports a case involving failure of the polyethylene liner of a Mecron bipolar hip prosthesis with impingement of varus metal shell on the femoral stem neck resulting in deep defect and impending fracture of femoral stem components.
CANONICAL REPRESENTATION OF STATIONARY QUANTUM GAUSSIAN PROCESSES
Authors: ACCARDI LUIGI , HIBINO YUJI
Published: October 2002

Stimulated by the quantum generalization of the canonical representation theory for Gaussian processes in Ref. 1, we first give the representations (not necessarily canonical) of two stationary Gaussian processes X and Y by means of white noises qt and pt with no assumptions on their commutator. We then assume that qt + ipt annihilates the vacuum state and prove that the representations are the joint Boson–Fock ones if and only if X and Y have a scalar commutator.
CONTINUOUS DEPENDENCE ON INITIAL DATA FOR SOLUTIONS OF NONLINEAR STOCHASTIC EVOLUTION EQUATIONS
Authors: DECK THOMAS
Published: October 2002

We consider stochastic evolution equations in the framework of white noise analysis. Contraction operators on inductive limits of Banach spaces arise naturally in this context and we first extend Banach's fixed point theorem to this type of spaces. In order to apply the fixed point theorem to evolution equations, we construct a topological isomorphism between spaces of generalized random fields and the corresponding spaces of U-functionals. As an application we show that the solutions of some nonlinear stochastic heat equations depend continuously on their initial data. This method also applies to stochastic Volterra equations, stochastic reaction–diffusion equations and to anticipating stochastic differential equations.
DIAGONALIZATION OF THE LÉVY LAPLACIAN AND RELATED STABLE PROCESSES
Authors: KUO HUI-HSIUNG , OBATA NOBUAKI , SAITÔ KIMIAKI
Published: October 2002

Eigenfunctions of the Lévy Laplacian with an arbitrary real number as an eigenvalue are constructed by means of a coordinate change of white noise distributions. The Lévy Laplacian is diagonalized on the direct integral Hilbert space of such eigenfunctions and the corresponding equi-continuous semigroup is obtained. Moreover, an infinite dimensional stochastic process related to the Lévy Laplacian is constructed from a one-dimensional stable process.
GENERATORS OF MEHLER-TYPE SEMIGROUPS AS PSEUDO-DIFFERENTIAL OPERATORS
Authors: LESCOT PAUL , RÖCKNER MICHAEL
Published: October 2002

We study semigroups (Pt)t ≥ 0 on a Hilbert space E, given by a Mehler-type formula: [Formula: see text] Under reasonable assumptions, the Lp(E,μ)-generator [Formula: see text] of (Pt)t ≥ 0 turns out to be expressible as a pseudo-differential operator, provided μ is an invariant measure for (Pt)t ≥ 0. The question of Lp-uniqueness is also answered positively.
A FLAT COPY OF THE ORNSTEIN–UHLENBECK OPERATOR ON THE PATH SPACE OVER A RIEMANNIAN MANIFOLD
Authors: LÖBUS JÖRG-UWE
Published: October 2002

A representation of a diffusion operator A on a certain space of right continuous trajectories in ℝd is derived. This operator A can be regarded as a flat copy of the Ornstein–Uhlenbeck operator on the path space over a Riemannian manifold. The correspondence to E. P. Hsu's representation of the Ornstein–Uhlenbeck operator is shown. Furthermore, an alternative treatment of conditional expectations of A is given.
ANALYTIC CHARACTERIZATION OF GENERALIZED FOCK SPACE OPERATORS AS TWO-VARIABLE ENTIRE FUNCTIONS WITH GROWTH CONDITION
Authors: JI UN CIG , OBATA NOBUAKI , OUERDIANE HABIB
Published: October 2002

Duality is established for new spaces of entire functions in two infinite dimensional variables with certain growth rates determined by Young functions. These entire functions characterize the symbols of generalized Fock space operators. As an application, a proper space is found for a solution to a normal-ordered white noise differential equation having highly singular coefficients.
A UNIFIED APPROACH TO GENERALIZED CONDITIONAL EXPECTATIONS OPERATOR VALUED WEIGHTS AND RADON–NIKODYM DERIVATIVES ON VON NEUMANN ALGEBRAS
Authors: CAVALLARO STEFANO , CECCHINI CARLO
Published: October 2002

Given two von Neumann algebras, ℳ and [Formula: see text] with [Formula: see text], and two normal semifinite faithful weights, φ and ψ on ℳ and [Formula: see text] respectively, we define a canonical map from {b ∈ ℳ+ | φ(b)< ∞} to the set of positive forms on the Hilbert space of the GNS representation of [Formula: see text] associated to ψ. We show that generalized conditional expectations, operator valued weights and Radon–Nikodym derivatives on von Neumann algebras can be obtained from particular cases of this canonical map.
RADONIFICATION OF CYLINDRICAL SEMIMARTINGALES BY A SINGLE HILBERT–SCHMIDT OPERATOR
Authors: JAKUBOWSKI ADAM , KWAPIEŃ STANISŁAW , DE FITTE PAUL RAYNAUD , ROSIŃSKI JAN
Published: October 2002

It is proved that in Hilbert spaces a single Hilbert–Schmidt operator radonifies cylindrical semimartingales to strong semimartingales. This improves a result due to Badrikian and Üstünel (also L. Schwartz), who needed composition of three Hilbert–Schmidt operators.
Risk-Based Deposit Insurance: An Application to Thailand
Authors: Tirapat Sunti
Published: October 2002

This paper investigates the application of option pricing to calculate the premium of deposit insurance in Thailand during the 1992-1996 period. In addition to applying the traditional Black- Scholes model, the barrier model of Boyle and Lee (1994) is examined. The barrier model takes the management (owners) action into account: the management (owners) may have a strong incentive to increase the volatility of the bank's assets, since this action increases the value of their equity. As suggested by the stylized evidence, most financial institutions in Thailand were "family owned", and there was inadequate corporate governance to prevent the incentive problems. The barrier model seems to fit the description of financial institutions in Thailand. The overall results show that the deposit insurance premiums of failed financial institutions are higher than the premiums of non-failed institutions. The evidence suggests that the option framework seems to be appropriate for pricing the premium: higher risk institutions pay higher insurance premiums. The results also show that the risk-based insurance premiums vary across time and on average are less than the premiums charged by the Financial Institutions Development Fund (FIDF).
RELAXING THE DIRICHLET ENERGY FOR MAPS INTO S2 IN HIGH DIMENSIONS
Authors: PAKZAD MOHAMMAD REZA
Published: October 2002

We prove the existence of a gap phenomenon, non-existent for the 3-dimensional case, for the relaxed Dirichlet energy of maps from a 4-dimensional domain into sphere.
FEASIBILITY OF ESTIMATING JOINT MOMENTS DURING GAIT WITH ONLY KINEMATIC DATA
Authors: SATO HARUHIKO , ANDREW PAUL D.
Published: October 2002

A preliminary model is presented for estimating floor reaction forces during human walking based only on kinematic data. Such a model would be useful for supplementing purely qualitative gait analysis performed in clinics where force plates would be an unaffordable luxury, but not for situations in which quantitative data would be used in making such decisions as how to perform an orthopedic surgery. In this model, the vertical components of floor reaction forces are determined by conventional double differentiation of kinematic data, but the horizontal (fore-aft) components are based instead on constraints in which the floor reaction forces are characterized as acting through the center of mass of the upper body. To assess the accuracy of our calculations, we gathered data of gait by a healthy 22-year-old woman using a motion analysis system with force plates. Pathological gait data were also examined. Joint moments were computed from both force plate data and from our estimates of floor reaction forces. Prediction of vertical force showed higher reliability than prediction of fore-aft force. Joint moments from kinematics were successfully calculated in normal gait, but not in pathological gait, especially at the hip joint. The proposed approach may have some merit for performing a gait analysis even when no force plate is present, but the inaccuracy increases in the case of a subject whose upper body sways during gait.
AGENT FABRICATION AND ITS IMPLEMENTATION FOR AGENT-BASED ELECTRONIC COMMERCE
Authors: GUAN SHENG-UEI , ZHU FANGMING
Published: October 2002

In the last decade, agent-based e-commerce has emerged as a potential role for the next generation of e-commerce. How to create agents for e-commerce applications has become a serious consideration in this field. This paper proposes a new scheme named agent fabrication and elaborates its implementation in multi-agent systems based on the SAFER (Secure Agent Fabrication, Evolution and Roaming) architecture. First, a conceptual structure is proposed for software agents carrying out e-commerce activities. Furthermore, agent module suitcase is defined to facilitate agent fabrication. With these definitions and facilities in the SAFER architecture, the formalities of agent fabrication are elaborated. In order to enhance the security of agent-based e-commerce, an infrastructure of agent authorization and authentication is integrated in agent fabrication. Implementation and prototype applications show that the proposed agent fabrication scheme brings forth a potential solution for creating agents in agent-based e-commerce applications.
DIFFERENT PROTONATION STATES OF THE BACILLUS CEREUS BINUCLEAR ZINC METALLO-β-LACTAMASE ACTIVE SITE STUDIED BY COMBINED QUANTUM MECHANICAL AND MOLECULAR MECHANICAL SIMULATIONS
Authors: GU WEI , ZHU JIANG , LIU HAIYAN
Published: October 2002

Three different protonation states of the active site of the Bacillus cereus zinc-β-lactamase in its binuclear form are studied using combined quantum mechanics/molecular mechanics molecular dynamics simulations. The reliability of the quantum mechanical model, the self-consistent-charge density-functional-based tight binding method, in describing the zinc centers are tested through comparisons with ab initio quantum mechanical results. We found that this model gave relatively accurate results for structures and performed much better than the MNDO type semi-empirical method for the particular systems. The enzyme simulations suggested that when the overall charge of the active site is +1, i.e., both Asp90 and Wat1 (a water molecule coordinated with the first zinc ion) deprotonated, the second zinc ion is coordinated with Asp90 and Wat1, and a second water molecule cannot coordinate with the second zinc ion. When the overall charge is +2, i.e., either Asp90 or Wat1 protonated, Asp90 and Wat1 form a stable hydrogen bond. Depending on the proton being on Asp90 or on Wat1, the active site structure produced by the simulations is either similar to molecule A or to molecule B, both contained in the same crystal structure that has two enzyme molecules in a single asymmetric unit. The simulations of the +2 charge states also reproduced the experimentally observed "loose" coordination around the second zinc for the Bacillus Cereus enzyme. Based on the simulations and a gas phase potential energy surface scanning using ab initio model, we argue that the penta-coordination around the second zinc ion is not a stable arrangement. Mechanistic implications of these results are discussed.
COUPLED GENETIC ALGORITHM/KOHONEN NEURAL NETWORK (GANN) FOR PROJECTION OF THREE-DIMENSIONAL PROTEIN STRUCTURES ONTO THE PLANE
Authors: ALPER KUTAY O. , BAGDASSARIAN CAREY K.
Published: October 2002

An algorithm is presented for projecting — at the amino acid level — the three-dimensional crystal structure of a protein molecule onto a planar surface. The scheme is topologically consistent: if two amino acid residues are closely juxtaposed in three-dimensional space, they remain so upon projection. Through such projections, a single resulting picture captures the spatial relations amongst a protein molecule's amino acids. Operationally, a genetic algorithm is used to "evolve" a parameter set which serves as input for a self-organizing Kohonen neural network responsible for the projection itself. A fitness function characterizing the quality of the projections is defined and maximized via the genetic algorithm. The workings of both the genetic algorithm and neural network are discussed in detail. In this work, we seek to optimize projections resulting from the inherently "frustrated" task of collapsing a space-filling collection of amino acid residues onto a simpler surface. Ultimately, the chosen application is a testing ground for establishing the success of our coupled genetic algorithm/Kohonen neural network scheme which can easily be adapted for other uses.
ENVIRONMENTAL ASSESSMENT IN VIETNAM: THEORY AND PRACTICE
Authors: OBBARD JEFFREY PHILIP , LAI YOKE CHIN , BRIFFETT CLIVE
Published: October 2002

Vietnam is a rapidly developing nation in Southeast Asia and has adopted and implemented mandatory legislation for Environmental Assessment since 1994. This review analyses the successes and failures of this legislation and investigates the role of strategic environmental assessment (SEA) in the future development of the country. Along with many other developing nations in the region, the implementation of existing environmental legislation is generally weak in Vietnam and increased efforts to educate, train and motivate responsible personnel in the government, non-government and private development sectors is a continuing requirement. Many overseas agencies are currently financing projects to meet these current needs and to develop sustainable development policy within the natural resource management and planning framework in the country. It is concluded that Vietnam does have a good potential for an increased application of SEA, but success will depend on the effective conversion of theory into practice.
IMPLEMENTATION OF ENVIRONMENTAL MANAGEMENT SYSTEMS STANDARDS: IMPORTANT FACTORS IN CORPORATE DECISION MAKING
Authors: EVANGELINOS KONSTANTINOS I. , HALKOS GEORGE E.
Published: October 2002

While environmental management systems standards (EMSS) have been advocated by policy makers and consultants on the basis of a number of benefits associated with their implementation, some companies are reluctant to implement them. This paper tests four hypotheses with regard to the significance of a number of factors in a company's decision to implement EMSS. Specifically, it assesses whether a company would be more likely to implement EMSS if its management has a positive perception of environmental issues; if there are pressures on the company to improve its environmental performance; if opportunities arise through its environmental activities; and if it operates in sensitive environmental conditions. For this purpose, Greek companies in the process of EMSS implementation were surveyed and their responses compared with companies that had not decided up to that point to implement the standards. Specific aspects of the hypotheses posed were supported and confirmed a range of factors that are important in a company's decision to implement EMSS.
COMPOSITE INSURER CONSIDERATION AND ATTITUDES ON ENVIRONMENTAL MANAGEMENT SYSTEMS CONCERNING PUBLIC LIABILITY POLICIES FOR POLLUTION RISKS
Authors: MINOLI D. M. , BELL J. N. B.
Published: October 2002

Pollution can incur costly clean-up programmes, erode company profits, and undermine governmental policy towards sustainable economic development. Governments and insureds are inquiring about insurance and environmental management systems (EMSs) to help prevent, control, and compensate for the risk of pollution. There is little analysis on using these instruments in defence of the environment. This issue is explored in a workshop and survey questionnaire on EMSs and public liability insurance concerning pollution risks in the UK market. EMSs might provide risk and claims assessment information, reduce pollution risks in the long term, and lead to comparatively lower insurance premiums. Insurers' rating, assessment, investigation, statistical and education work with regard to pollution risks is in its infancy and there is little knowledge, poor recognition and low confidence in EMSs. Political, practical, economic and legal problems impede insurers' capacity to reply positively to pollution risks and EMSs. Failure to overcome these issues reduces the insurers' and insureds' ability to prevent and control the risk of pollution and lessen its aftermath of detrimental consequences.
EIA FOLLOW-UP IN SOUTH AFRICA: CURRENT STATUS AND RECOMMENDATIONS
Authors: HULETT JACKY , DIAB ROSEANNE
Published: October 2002

EIA is widely used as a tool to aid environmental decision making and through the processes of assessment, mitigation and public participation should contribute to sound environmental management and promote sustainable development. However, EIA often places greatest emphasis on the stages leading up to the Record of Decision, with little concern for the subsequent monitoring and auditing of impacts. In this paper, the status of EIA follow-up in South Africa is assessed through interviews with environmental practitioners and regulatory authorities. Their understanding of EIA follow-up and views on its enforcement, together with an assessment of current practices, have provided a useful background for the development of various models of EIA follow-up. Four models, which represent different approaches to EIA follow-up, are discussed. They are termed the legally-based approach, the partnership approach, the self-regulatory and the incentive/disincentive approaches. An evaluation of each in terms of its contribution to environmental sustainability principles is given and recommendations made for the inclusion of EIA follow-up as a standard component of the EIA process.
INSURER PERCEPTION OF ENVIRONMENTAL MANAGEMENT SYSTEMS REGARDING INSURANCE FOR POLLUTION
Authors: MINOLI D. M. , BELL J. N. B.
Published: October 2002

This paper explores the use of insurance and environmental management systems (EMSs) to prevent and control the risk of pollution. To assess this issue, a series of interviews with insurers was conducted to find out their opinions and attitudes on EMSs about insurance for pollution. The main scope of the research is composite insurance, public liability and EMSs, within the UK market. Insurers' believed that EMSs could theoretically help insureds and insurers, respectively, prevent and control, and assess and settle pollution. However, there is little evidence to support this assertion. Moreover, EMSs assess pollution incompletely from the insurers' point of view. Furthermore, insurers' initial assessment and post loss investigation of pollution are generally not well developed, and there is little knowledge about and poor recognition of EMSs. Economic, practical, legal and political issues hinder insurers' ability to respond positively to EMSs. Therefore, insurance and EMSs are insufficiently developed to play a lead role in lessening the risk of pollution.
Coherent Layered Structures in Fe/Au Monatomic Multilayers with Addition of Fractional Atomic Layers
Authors: Mitani Seiji , Takanashi Koki , Shigemoto Yasutaka , Fujimori Hiroyasu
Published: October 2002

Fractional numbers of atomic layers have been introduced intentionally into Fe/Au monatomic multilayers in order to investigate the effect of the deviation from monatomic layer thickness on the layered structure. We prepared [ Fe(1+δ ML)/Au(1+δ ML)] multilayers with the fraction δ=0, 0.25 and 0.5, where ML represents monatomic layer thickness. The superlattice (001) peak associated with the L10 ordered structure is observed in the X-ray diffraction profile for δ=0. For δ=0.25 and 0.5, on the other hand, the superlattice (001) peak is split into a couple of sharp peaks. The appearance of those two peaks indicates the formation of coherent layered structure with long-range periodicity, even for samples with fractional atomic layers.
COMPARATIVE GENOMIC ANALYSIS OF PLANT-ASSOCIATED BACTERIA
Authors: Van Sluys M. A. , Monteiro-Vitorello C. B. , Camargo L. E. A. , Menck C. F. M. , da Silva A. C. R. , Ferro J. A. , Oliveira M. C. , Setubal J. C. , Kitajima J. P. , Simpson A. J.
Published: October 2002

▪ Abstract  This review deals with a comparative analysis of seven genome sequences from plant-associated bacteria. These are the genomes of Agrobacterium tumefaciens, Mesorhizobium loti, Sinorhizobium meliloti, Xanthomonas campestris pv campestris, Xanthomonas axonopodis pv citri, Xylella fastidiosa, and Ralstonia solanacearum. Genome structure and the metabolism pathways available highlight the compromise between the genome size and lifestyle. Despite the recognized importance of the type III secretion system in controlling host compatibility, its presence is not universal in all necrogenic pathogens. Hemolysins, hemagglutinins, and some adhesins, previously reported only for mammalian pathogens, are present in most organisms discussed. Different numbers and combinations of cell wall degrading enzymes and genes to overcome the oxidative burst generally induced by the plant host are characterized in these genomes. A total of 19 genes not involved in housekeeping functions were found common to all these bacteria.
Elevated Serum C-Reactive Protein Levels and Early Arterial Changes in Healthy Children
Authors: Järvisalo Mikko J. , Harmoinen Aimo , Hakanen Maarit , Paakkunainen Ulla , Viikari Jorma , Hartiala Jaakko , Lehtimäki Terho , Simell Olli , Raitakari Olli T.
Published: October 2002

Objective—

Elevated serum concentration of C-reactive protein (CRP) predicts cardiovascular events in adults. Because atherosclerosis begins in childhood, we undertook a study to determine whether changes in brachial artery endothelial function and the thickness of the carotid intima-media complex, 2 markers of early atherosclerosis, are related to CRP levels in healthy children.

Methods and Results—

Brachial artery flow-mediated dilatation (FMD) and carotid artery intima-media thickness (IMT) were measured with ultrasound in 79 children (aged 10.5±1.1 years). Compared with the children with CRP levels under the detection limit (<0.1 mg/L, n=40, group 1), the children with higher CRP (0.1 mg/L≤CRP≤0.7 mg/L, n=20, group 2; CRP >0.7 mg/L, n=19, group 3) had lower FMD (9.0±4.4% versus 7.8±3.3% versus 6.5±2.6%, respectively;
P
=0.015 for trend) and greater carotid IMT (0.45±0.03 versus 0.46±0.04 versus 0.49±0.06 mm, respectively,
P
=0.002 for trend). CRP level remained a statistically significant independent predictor for brachial FMD and carotid IMT in multivariate analyses.

Conclusions—

These data suggest that CRP affects the arteries of healthy children by disturbing endothelial function and promoting intima-media thickening. The findings support the hypothesis that CRP plays a role in the pathogenesis of early atherosclerosis.