bluuebunny/crossref_metadata_2025 huggingface dataset:
SPATIAL CORRELATIONS OF CHAOTIC WAVE FUNCTIONS
Authors: PRIGODIN VLADIMIR N. , TANIGUCHI NOBUHIKO
Published: October 2004

The statistics of the spatial correlations of eigenfunctions is investigated in chaotic systems with or without time-reversal symmetry. It is rigorously shown that wave functions corresponding to different energy levels are uncorrelated in space. At a given eigenstate, we find that though the background of wave function density fluctuates strongly, there exist the long-standing Friedel oscillations in wave function intensity. The joint distribution of the intensity at two separate space points is presented by the universal law with one parameter — the average amplitude correlation. This distribution encompasses two different regions: One with an independent joint distribution for small values of density fluctuations, and the other showing an increasing spatial correlation for the large fluctuations.
EXACT BOUNDARY MAGNETIZATION OF THE LAYERED ISING MODEL ON TRIANGULAR AND HONEYCOMB LATTICES
Authors: PELIZZOLA ALESSANDRO
Published: October 2004

In the present paper we extend a previous exact calculation of the boundary magnetization of the square lattice layered Ising model, based on a transfer-matrix effective-field technique, to the triangular lattice. The result is then further extended to the honeycomb lattice by means of a star-triangle transformation. Finally, the (11) boundary of the square lattice is analyzed as a particular case of the triangular and honeycomb lattices.
SENSITIVE DEPENDENCE OF LIFETIMES OF CHAOTIC TRANSIENT ON NUMERICAL ACCURACY FOR A MODEL WITH DRY FRICTION AND FREQUENCY DEPENDENT DRIVING AMPLITUDE
Authors: PAAR V. , PAVIN N.
Published: October 2004

Chaotic transients are investigated for a one-dimensional model, which is a driven non-linear system having frequency dependent driving amplitude, with weak dissipation consisting of Coulomb and quadratic friction. It is shown that lifetimes of chaotic transients are sensitively dependent on numerical accuracy when the initial condition is fixed and approximately follow the exponential decay law, which cannot be distinguished from the well-known exponential decay law for dependence on initial conditions when the numerical precision is fixed.
A POSSIBLE NEW TYPE OF SUPERCONDUCTIVITY
Authors: DAS M.P. , TASSIE L.J.
Published: October 2004

It is suggested that the mechanism for superconductivity proposed by Witten for cosmic strings can also occur in the laboratory. Each term in Witten’s Lagrangian has an analogue in the theory of condensed matter physics. The parameters in condensed matter are many orders of magnitude different from those in cosmic strings. Some estimates of the possible superconducting properties are given.
FAR-INFRARED EMISSION BY HEATED ELECTRONS IN A TWO-DIMENSIONAL SEMICONDUCTOR SYSTEM
Authors: XU W.
Published: October 2004

In this letter, we present a detailed theoretical study that explores the possibility to use AlGaAs/GaAs-based two-dimensional semiconductor systems (2DSSs) as the far-infrared (FIR) generators at zero-magnetic field and by electrically heated electrons. A simple model from which the intensity of FIR radiation can be calculated as a function of photon frequency is developed by calculating the electron-energy-loss induced by hot-electron interaction with electromagnetic field, mediated by electron-phonon scattering. The main results obtained from the present study are: (1) in a 2DSS, FIR radiation is mainly generated among the different electronic subbands; (2) the polarization of FIR generated from a 2DSS is along the growth direction; (3) the intensity of FIR radiation increases rapidly with increasing energy excitation, i.e., with electron temperature; (4) the frequency of electromagnetic wave generated is around ω~|εm– εn|/ħ with εn the electronic subband energy; and (5) for an AlGaAs-GaAs-AlGaAs single quantum well structure, the frequency of the FIR emission can be tuned by varying the width of the well layer. We have also studied the influence of electron density, lattice temperature, etc. on the FIR emission by heated electrons in 2DSSs.
A SEMI-EMPIRICAL STUDY OF SMALL COPPER CLUSTERS
Authors: DATTA RADHIKA PROSAD , BANERJEA AMITAVA , MOOKERJEE ABHIJIT , BHATTACHARYYA A.K.
Published: October 2004

We study the structure and electronic properties of small copper clusters using Equivalent Crystal Theory (ECT) and a parametrised LCAO method. The cluster geometry is optimised using ECT with Monte Carlo techniques. The LCAO method, particularly the parametrisation scheme due to Harrison, is then used to study the electronic properties of the optimised clusters.
ANISOTROPIC XY MODEL FOR TWO-DIMENSIONAL Fe
Authors: RAU C. , ROBERT M.
Published: October 2004

New results on the magnetic properties of two-dimensional (2D) Fe(100) films close to and far from the Curie point are presented. The nonuniversal critial behavior found for these 2D Fe films grown on Pd(100) and Au(100) substrates is shown to be consistent with theoretical predictions for the 2D XY model with two-fold and four-fold symmetry-breaking perturbations.
INTEGRABLE TWO-PARAMETER MODEL OF THE FERMI GAS
Authors: KARNAUKHOV IGOR N.
Published: October 2004

We present a two-band model of the gas of fermions consisting of a parabolic band of conduction electrons and a band of local pairs interacting via a δ-function interband interaction. The model is integrable and its solution has been obtained by means of the Bethe ansatz. The ground state energy and the density of conduction electrons have been calculated numerically.
ACCEPTOR-RELATED RADIATIVE RECOMBINATION OF QUASI-TWO-DIMENSIONAL ELECTRONS IN MODULATION-DOPED GaAs/AlxGa1−xAs HETEROJUNCTIONS
Authors: CHUA S.J. , XU S.J. , TANG X.H.
Published: October 2004

The radiative recombination of quasi-two-dimensional electrons with photoexcited holes bound to acceptors is investigated in modulation-doped GaAs / Al x Ga 1–x As heterojunctions. With increase in temperature, a blue shift of about 2.5 meV is observed for a temperature change from 4 K to 40 K. Also, observed is a rapid decrease in intensity of its low energy peaks. This change in line shape of the acceptor-related emission in the GaAs / Al x Ga 1–x As heterojunctions is accounted for by the effect of band bending and the spatial distribution of acceptors.
STRONG COUPLING THEORY OF IMPURE SUPERCONDUCTORS: REAL SPACE FORMALISM
Authors: KIM YONG-JIHN
Published: October 2004

In the electron–phonon model, the influence of nonmagnetic impurities on the transition temperature of superconductors is revisited. Anderson’s pairing condition between time-reversed eigenstate pairs is derived from the physical constraint of the Anomalous Green’s function. After this pairing condition is incorporated into the self-consistency equation, one may find that the phonon-mediated interaction decreases exponentially by localization.
FRUSTRATION IN THE PYROCHLORE ANTIFERROMAGNETS
Authors: HARRIS M.J. , ZINKIN M.P.
Published: October 2004

In an antiferromagnet with the pyrochlore structure, the magnetic ions are situated on a framework of corner-sharing tetrahedra. This lattice results in a high degree of geometrical frustration, and theoretical studies predict that the magnetic ground state is continuously disordered. The majority of pyrochlore compounds are observed to remain disordered down to the lowest temperatures, and susceptibility measurements show that they often behave as conventional spin glasses. Neutron diffraction studies have discovered strong magnetic diffuse scattering at low temperatures. This reveals the presence of very short-ranged ferro- and antiferromagnetic correlations, similar in nature to the short-range correlations in a liquid. In this article, we review the current theoretical and experimental understanding of the pyrochlores, and present the results of recent experiments which have investigated the static and dynamic properties of this short-range order.
STUDY OF DOPING EFFECT ON THE ELECTRONIC STRUCTURE OF Sr1−xLaxTiO3
Authors: PARI G. , RAMAKUMAR R. , MOOKERJEE ABHIJIT
Published: October 2004

We have studied the doping effects of the electronic structure of Sr 1−x La x TiO 3 for x=0, 0.25, 0.5, 0.75, 1, using the Tight-Binding Linearized Muffin Tin Orbitals (TB-LMTO) method. The calculated energy gap of SrTiO 3(x=0) shows an excellent agreement with the experimental result. The system goes to metallic phase for 0<x<0.95 and goes to an antiferromagnetic phase for x=1, agreeing well with the experimental observations. The cohesive energies for the above mentioned x values are also calculated.
PHASE SEPARATION OF TWO-DIMENSIONAL FLUID MIXTURES IN THE DISSIPATIVE REGIME
Authors: LEPTOUKH GREGORY , STRICKLAND BOWE , ROLAND CHRISTOPHER
Published: October 2004

The phase separation of two-dimensional fluid mixtures was investigated with Molecular Dynamics simulations. The behavior of both single-component and binary mixtures as a function of temperature, volume fraction and average fluid density was studied. Binary systems with a size mismatch were also considered. In all cases, the diffusive coalescence of clusters is the primary mechanism of growth. In binary systems, the shape transformations of merging droplets induce important long-range flows at high volume fractions.
MAGNETIC SUSCEPTIBILITY OF A DISORDERED HIGH TEMPERATURE SUPERCONDUCTOR
Authors: GROSU I. , CRISAN M. , TIFREA I.
Published: October 2004

The temperature and the disorder dependence of the magnetic susceptibility of electrons interacting with spin fluctuations has been calculated. The system is considered to be two-dimensional and the dynamical susceptibility correspond to a strongly correlated electron system in the presence of weak disorder. We obtain deviations from Pauli paramagnetism which are in good agreement with experimental data.
ELECTRONIC STRUCTURES OF PURPLE BRONZE KMo6O17 STUDIED BY X-RAY PHOTOEMISSION SPECTRA
Authors: QIN XIAOKUI , WEI JUNYIN , SHI JING , TIAN MINGLIANG , CHEN HONG , TIAN DECHENG
Published: October 2004

X-ray photoemission spectroscopy study has been performed for the purple bronze KMo 6 O 17. The structures of conduction band and valence band are analogous to the results of ultraviolet photoemission spectra and are also consistent with the model of Travaglini et al., but the gap between conduction and valence band is insignificant. The shape of asymmetric and broadening line of O-1s is due to unresolved contributions from the many inequivalent oxygen sites in this crystal structure. Mo 3d core-level spectrum reveals that there are two kinds of valence states of Molybdenum (Mo+5 and Mo +6). The calculated average valence state is about +5.6, which is consistent with the expectation value from the composition of this material. The tail of Mo-3d spectrum toward higher binding energy is the consequence of the excitation of electron-hole pairs with singularity index of 0.21.
A DEFORMED BOSE-EINSTEIN GAS NEAR q=1
Authors: PINHEIRO A.B. , RODITI I.
Published: October 2004

We show that the Bose–Einstein condensation occurs, on the region near q=1, for modified ideal deformed gas.
QUANTIZATION OF CLASSICAL CONSTANTS OF MOTION AND EQUILIBRIUM DISTRIBUTIONS IN QUANTUM MECHANICS
Authors: HABA Z.
Published: October 2004

We distinguish a class of quantum systems (trigonometric and hyperbolic potentials) with an additional constant of motion unrelated to any symmetry. The various quantum constants of motion result from non-uniqueness of the quantization procedure. We discuss equilibrium distributions in quantum statistical mechanics determined by the constants of motion.
SCATTERING OF PIONS AND CHANNELED MUONS BY IMPURITIES IN SINGLE CRYSTALS
Authors: SIDDIQUI AZHER M. , HARIKUMAR V. , GOTETI L.N.S. PRAKASH , PATHAK ANAND P.
Published: October 2004

The possibility of pions and muons being used as probe particles for defects studies in materials research has been investigated for the past thirty years or so. We discuss here the similarities of π+ and µ+ with positrons and tritons so that they can be treated as light hydrogen isotopes. Incident pions occupy a lattice site (substitutional or interstitial) and then decay into muons of energy 4.12 MeV which undergo channeling effects. The scattering cross-section of pions in tantalum single crystal with oxygen impurities has been evaluated applying Born approximation and using a double screened potential. The same calculation is applicable for muons after making some relativistic corrections. This model should also be applicable in various other situations where dechanneling by heavy ion impurities existing in multiple charge states takes place in an otherwise perfect single crystal.
SURFACE ORDER-PARAMETER DEPRESSION AND PAIR SYMMETRY IN HIGH-Tc JOSEPHSON JUNCTIONS
Authors: GONNELLI R.S. , UMMARINO G.A.
Published: October 2004

In the present letter we discuss the effect of the intrinsic surface depression of the order parameter on the temperature dependence of the Josephson critical current in high-T c SIS and SIS′ junctions. The theoretical results are compared to the Ic(T)RN(T) curves we recently obtained from reproducible data of break junctions made at 4.2 K in single crystals of Bi 2 Sr 2 CaCu 2 O 8+x and Bi 2 Sr 2 CuO 6+x as well as to the experimental data of multilevel edge junctions YBa 2 Cu 3 O 7+x/ SrTiO 3/ YBa 2 Cu 3 O 7+x and of planar tunnel junctions YBa 2 Cu 3 O 7+x/native barrier/Pb. In all the studied junctions, the s-wave depressed-gap model can accurately reproduce the large deviations from the BCS behavior, both in shape and magnitude. The comparison with the results of a model that explains the same deviations in YBa 2 Cu 3 O 7+x junctions by assuming a s+id pair symmetry with a dominant d-wave component shows that our sample-independent depressed-gap model alone can fully explain the I c (T)RN(T) values, while the s+id model needs some additional current-lowering mechanism to do the same.
PHASE OF AHARONOV-BOHM OSCILLATIONS IN CONDUCTANCE OF MESOSCOPIC SYSTEMS
Authors: DEO P.S. , JAYANNAVAR A.M.
Published: October 2004

Motivated by a recent experiment we analyze in detail the phase of Aharonov-Bohm oscillations across a 1D ring with a stub coupled to one of its arms, in the presence of a magnetic flux. We demonstrate that there are two kinds of conductance extremas. One class of them are fixed at particular flux values and can only change abruptly from a maxima to a minima as incident energy is varied. We show a different mechanism for such abrupt phase change in conductance oscillation. We demonstrate that these extremas can exhibit “phase locking”. However, the second kind of extremas can shift continuously as the incident energy is varied.
THE SETTLEMENT FOR THE DEBATE ON THE PENETRATION DEPTH EXPERIMENTS IN THE HIGH-Tc CUPRATES
Authors: LIU FU-SUI , WANG JING-YI
Published: October 2004

This paper shows that the cuprates being of higher than 80 K T c have two types of dependences of the penetration depth on temperature, which can settle the debates of the penetration depth experiments in the high-T c cuprates.
METAL-INSULATOR TRANSITION AND FRÖHLICH CONDUCTIVITY IN THE SU-SCHRIEFFER-HEEGER MODEL
Authors: MICHIELSEN KRISTEL , RAEDT HANS DE
Published: October 2004

A quantum molecular dynamics technique is used to study the single-particle density of states, Drude weight, optical conductivity and flux quantization in the Su-Schrieffer-Heeger (SSH) model. Our simulation data show that the SSH model has a metal-insulator transition away from half-filling. In the metallic phase the electron transport is collective and shows the features characteristic of Fröhlich conductivity.
EFFECTS OF NEXT-NEAREST-NEIGHBOR HOPPING INTERACTION ON THE STRUCTURE OF ELECTRONIC ENERGY BANDS OF POLYDIACETYLENES
Authors: HU H.F. , YAO K.L.
Published: October 2004

Starting from the extensional model Hückel Hamiltonian containing the next-neighbor hopping interactions, the energy band structure and their variation have been studied for polydiacetylenes (PDA’s). With the increase of the next-neighbor hopping interaction parameter ρ the results show that: (1) the electronic state symmetry is broken, (2) the locations and the widths of energy bands have been changed, and (3) the energy gap becomes narrower and the total bandwidth broader. Finally, the effect of the nextneighbor hopping interactions on the band-structure is discussed.
INTERATOMIC CORRELATION MOMENTS AND MEAN SQUARE RELATIVE DISPLACEMENTS IN AN ANHARMONIC CRYSTAL WITH THE FACE-CENTERED CUBIC LATTICE
Authors: ZUBOV V.I. , PASCUAL M.F. , RODRIGUES C.G.
Published: October 2004

Using the correlative method of unsymmetrized self-consistent field we study the dynamical properties of anharmonic crystals, namely, the quadratic correlations between atomic displacements from the equilibrium positions and their mean square relative displacements in anharmonic crystals. In the present paper we calculate these values for a weakly anharmonic crystals with the face-centered cubic lattice in which the nearest neighbors interact. The second order of the method enables one to calculate for this lattice the correlations between the nearest, second, third and fourth neighbors. The results are compared with those obtained previously for simplified models. The dependence on the coordination number and on the dimensionality of the lattice is discussed.
DYNAMICAL DIMENSION SPLITTING ON FRACTALS: STRUCTURES WITH DIFFERENT DIFFUSIVE AND VIBRATIONAL SPECTRAL DIMENSIONS
Authors: BURIONI RAFFAELLA , CASSI DAVIDE , REGINA SOFIA
Published: October 2004

On fractals and inhomogeneous structures that have been studied up to now, a single parameter, the spectral dimension, rules diffusion and vibrational dynamics. However, in principle, two distinct parameters could be necessary to describe the two physical phenomena. In this paper we show the existence of fractal structures where two different spectral dimensions are required. Random walks and vibrational spectrum are studied by renormalization group as well as alternative techniques to obtain the exact values of the dimensions and to clarify the origin of such dynamical dimension splitting.
PHOTOEMISSION STUDIES OF Pd AND Pt IMPURITIES ON AND IN SILVER
Authors: SCHNEIDER W.-D. , PATTHEY F. , ROY H.-V. , SCHAFFNER M.-H. , DELLEY B.
Published: October 2004

The electronic structure of Pd and Pt atoms adsorbed on the (100), (110), and (111) surfaces of silver and of the related dilute alloys has been studied at different temperatures using ultraviolet photoelectron spectroscopy (UPS). The observed differences in lineshape of the virtual bound palladium 4d (platinum 5d) state on isolated atoms supported on the differently oriented surfaces in comparison with an impurity atom embedded in the first layer and in the bulk are well accounted for by a many-body calculation performed within the Anderson single impurity model. This analysis clearly indicates a stronger sd-hybridization in the bulk than at the surface, consistent with the change in coordination number.
A NEW METHOD FOR STUDYING SEMICONDUCTING SURFACES IN AIR BY SCANNING TUNNELING MICROSCOPY
Authors: FERLAUTO A.S. , QUIVY A.A.
Published: October 2004

We used a new method for studying GaAs surfaces in air with a home-made scanning tunneling microscope. The oxide layer was chemically removed, and the sample was prevented from re-oxidation by a thin layer of mineral oil (NOJOL). MBE-grown GaAs layers and In As quantum dots were successfully imaged.
STRUCTURE SIMULATIONS OF LIQUID S AND LIQUID Te BY UNCONSTRAINED REVERSE MONTE CARLO METHOD
Authors: ANDRECUT M.
Published: October 2004

A spatial atomic distribution model of liquid S (L-S) and liquid Te (L-Te) was generated by using the experimental diffraction data and reverse Monte Carlo method without applying structural constraints. The obtained models have been analysed in terms of near-atomic-neighbour, bond-angle distribution, three-body correlations and chain statistics. The analysis of the generated models has shown that the three-dimensional structure of the investigated liquids can be well described as a network of short chains.
ON THE NONLINEAR SUSCEPTIBILITY OF THE QUANTUM ISING SPIN GLASS MODEL IN A RANDOM FIELD
Authors: BUSIELLO G. , SABUROVA R.V.
Published: October 2004

We calculate the static bulk nonlinear susceptibility for Ising spin glass model with pairwise interactions, in a transverse field and longitudinal random field. Paramagnetic-spin glass transition is considered and connections with previous theoretical and experimental results are made.
ESTIMATION OF THE DOPING DEPENDENCE OF ANTIFERROMAGNETISM IN THE COPPER OXIDE MATERIAL
Authors: FENG SHIPING , SONG YUN , HUANG ZHONGBING
Published: October 2004

Within the t-J model, we study the doping dependence of antiferromagnetism in the copper oxide materials by considering quantum fluctuations of spinons in the randomphase-approximation. The staggered magnetization vanishes around doping δ=5% for a reasonable parameter value t/J=5, which is in agreement with the experiments on copper oxide materials.
PHOTOCONDUCTIVITY OF PHENANTHRENE SINGLE CRYSTALS
Authors: SALEH M. , RANA ANWAR MANZOOR , SHAHID GUL NAWAZ , ALI MAZHAR
Published: October 2004

Single crystals of phenanthrene were grown from the melt in specially designed crystal growth tubes. Over the wavelength range studied: 200–650 nm, surface photoconductivity at room temperature is independent of photon energy >3.5 eV for applied bias fields ~10 kV cm−1. This is interpreted as saturation of the generation process for both electron and hole carriers. However, bulk photoconductivity for photon energy <3.5 eV at room temperature is dependent on photon energy and applied bias fields and generation mechanism involved in this case is attributed to exciton-exciton collisions and photoionization of excitons.
EFFECTS OF ORIENTATION ON THE ELECTRONIC STRUCTURE OF K3C60
Authors: LU JING , ZHANG LIYUAN , CAO ZILIANG
Published: October 2004

Electronic structure of K 3 C 60 in the ordered bidirectional and quadridirectional structure (space group [Formula: see text]) and in the disordered bidirectional structure (space group [Formula: see text]) is examined. As compared with the unidirectional structure (space group [Formula: see text]), the lower-energy peak of the conduction band in the [Formula: see text] structures is split into two, the higher-energy peak is strongly depressed, and the value of DOS at the Fermi level (N(E F )) is enhanced. Orientational disorder almost completely washs out the structure in the DOS of the conduction band; however, the value of N(E F ) differs slightly from that in the unidirectional structure.
A MAIN DIMER OF FULLERENES: C118
Authors: YU XUEPING , CAO ZHILIANG , HAN RUSHAN
Published: October 2004

A photopolymerization of C 60 molecules occurs in the irradiation of oxygen-free C 60 film with visible or ultraviolet light. Results from mass spectroscopy indicate that C 118 is the principal dimer among the dimers around C 120. Three most possible isomers of C 118 are presented and studied. Geometries are optimized with tight-binding method and two techniques. Vibrational modes are also obtained. Their stretching frequencies are from 106 cm −1 to 133 cm −1, which are consistent with the experimental value 116 cm −1.
CALCULATION OF THE CRYSTAL FIELD IN CeZn2
Authors: ANDRECUT MIRCEA
Published: October 2004

The temperature dependence of the second-order crystalline electric field (CEF) parameters of rare earth intermetallic compound CeZn 2 was deduced from the least-squares nonlinear fit to the reciprocal paramagnetic susceptibility along principal crystalline axes. The results of the calculation are in good agreement with the experimental values.
INFLUENCE OF SUBSTRATE TREATMENTS ON MORPHOLOGY AND ADHESION OF CARBON COATINGS ON QUARTZ
Authors: HOU QINGRUN , GAO J.
Published: October 2004

The influence of different treatments of quartz substrate on morphology and adhesion of carbon coatings was studied. The surfaces of quartz substrates were abraded by using fine and coarse abrasive papers respectively to develop rough surface features. Adherent carbon coatings with different surface roughness were obtained. In order to grow adherent carbon coatings with very smooth surfaces, a silicon intermediate layer was grown by means of electron beam evaporation. Carbon coatings deposited on the intermediate layers were adherent to the quartz substrates.
STATIC STRUCTURE FACTOR OF HARD-SPHERE YUKAWA SYSTEMS
Authors: RINO JOSÉ-PEDRO , STUDART NELSON
Published: October 2004

We have applied the Singwi, Tosi, Land and Sjölander approximation for the two-particle distribution function in the BBGKY hierarchy equations to investigate the properties of the hard-sphere Yukawa systems. The static structure factor and the radial distribution function are evaluated and compared with other approximations of the theory of liquids and computer simulations.
TESTING THE FALL-BACK DISK MODEL FOR RADIO PULSARS USING NEW DATA
Authors: TAGIEVA S. O.
Published: October 2004

The fall-back matter model to explain the [Formula: see text] evolution of radio pulsars is beginning to attract attention. In this work we test this model using the most up-to-date data. It is found that the age predictions of this model contradict the observational data.
LIFETIME MEASUREMENTS OF EXCITED STATES IN 73As
Authors: SINGH K. P. , KAKAVAND T. , HAJIVALIEI M.
Published: October 2004

The excited states of 73 As have been investigated via the 73 Ge ( p , n γ)73 As reaction with proton beam energies from 2.5–4.3 MeV. The lifetimes of the levels at 769.6, 860.5, 1177.8, 1188.7, 1274.9, 1344.1, 1557.1 and 1975.2 keV excitation energies have been measured for the first time using the Doppler shift attenuation method. The angular distributions have been used to assign the spins and the multipole mixing ratios using statistical theory for compound nuclear reactions. The ambiguity in the spin values for the various levels has been removed. The multipole mixing ratios for eight γ-transitions have been newly measured.
ON THE ANALYSIS OF THE EIGENVALUES OF THE DIRAC EQUATION WITH A 1/r POTENTIAL IN D DIMENSIONS
Authors: DONG SHI-HAI , LOZADA-CASSOU M.
Published: October 2004

The Dirac equation is investigated in D+1 dimensional space-time. The radial equations of this quantum system are obtained and solved exactly by the confluent hypergeometric equation approach. The energy levels E(n,l,D) are analytically presented. For the continuous dimension D as proposed by Nieto, the dependences of the energy difference ΔE(n,l,D) for D and D-1 on the dimension D are demonstrated as three different kinds of change rules. The dependences of the energy E(n,l,D) on the dimension D are also discussed. It is found that the energies E(n,l,D) (l≠0) are almost independent of the quantum number l for a large D, while E(n,0,D) first decreases and then increases with the increasing dimension D. The dependences of the energies E(n,l,ξ) on the potential strength ξ are also studied for the given dimension D=3. We find that the energies E(n,l,ξ) decrease with ξ≤l+1.
NUMERICAL GREEN’S FUNCTION SOLUTION OF THE HELMHOLTZ EQUATION
Authors: MARSCHALL R.A.
Published: October 2004

A promising new fast (of order N log 2N)method for finding the numerical solution of broad classes of partial differential equations is introduced. This method is referred to as the Iterative Dual Domain Method (IDDM), since its iterations occur in both transformed and untransformed domains. The specific example used is the Helmholtz equation for both homogeneous and almost arbitrarily inhomogeneous media. Preliminary indications of the algorithm’s performance are illustrated by examples of: wave focusing through a thick lens, scattering from an inclusion, and guided waves in layered media.
ACCURATE FINITE DIFFERENCE REPRESENTATION OF NEUMANN BOUNDARY DATA FOR TIME-HARMONIC WAVE PROPAGATION
Authors: HARARI ISAAC
Published: October 2004

Finite difference stencils for inhomogeneous Neumann boundary conditions in acoustic problems with arbitrary source distributions are constructed and analyzed. Boundary stencils are compatible with corresponding interior stencils, preserving symmetry of matrix equations without degrading global accuracy. Higher-order accuracy is attained within the compact support of lower-order methods. Results are verified by local truncation error analysis.
AUTOMATIC PATTERN CONSTRUCTION FOR WEB INFORMATION EXTRACTION
Authors: GAO XIAOYING , ZHANG MENGJIE , ANDREAE PETER
Published: October 2004

This paper describes a domain independent approach for automatically constructing information extraction patterns for semi-structured web pages. Given a randomly chosen page from a web site of similarly structured pages, the system identifies a region of the page that has a regular "tabular" structure, and then infers an extraction pattern that will match the "rows" of the region and identify the data elements. The approach was tested on three corpora containing a series of tabular web sites from different domains and achieved a success rate of at least 80%. A significant strength of the system is that it can infer extraction patterns from a single training page and does not require any manual labeling of the training page.
INTERVAL METHODS IN KNOWLEDGE REPRESENTATION
Authors: KREINOVICH VLADIK
Published: October 2004

This section is maintained by Vladik Kreinovich. Please send your abstracts (or copies of papers that you want to see reviewed here) to vladik@cs.utep.edu, or by regular mail to: Vladik Kreinovich, Department of Computer Science, University of Texas at El Paso, El Paso, TX 79968, USA.
CHARACTERIZATIONS OF LOW-FREQUENCY NOISE IN LASER-DEBONDED HVPE-GROWN GaN THIN FILMS
Authors: CHAN C. P. , LEUNG B. H. , LOKE Y. H. , MAN H. C. , YUE T. M. , XIU X. , ZHANG R. , SURYA C.
Published: October 2004

Low-frequency excess noise was measured on laser-debonded HVPE-grown GaN films. While the Schottky MSM devices, fabricated on 5 μm-thick films, demonstrated reduction in the noise level, the ohmic MSM devices showed significant increase in the low-frequency noise. To account for the data we conducted two-dimensional simulation of the temperature of the GaN layer as a function of time and distance from the GaN/sapphire interface. The simulation results show that the temperature at the GaN/sapphire interface may rise up to 1400 K, whereas the maximum temperature at the GaN surface was about 400 K at the. Based on the experimental data and the simulation results, it is postulated that the illumination of the GaN sample by high-power excimer laser led to the decomposition of GaN at the GaN/sapphire interface resulting in the generation of localized states at the interface. The same process may have led to some thermal annealing effect at the GaN surface. To provide experimental proof of the hypothesis, detailed low-frequency noise measurement on ohmic MSM devices fabricated on 20 μm-thick GaN films were performed. The results indicate similar noise level for both the debonded and the control devices.
Mechanisms of membrane estrogen receptor-α-mediated rapid stimulation of Ca2+levels and prolactin release in a pituitary cell line
Authors: Bulayeva Nataliya N. , Wozniak Ann L. , Lash L. Leanne , Watson Cheryl S.
Published: October 2004

The role of membrane estrogen receptor-α (mERα) in rapid nongenomic responses to 17β-estradiol (E2) was tested in sublines of GH3/B6 rat prolactinoma cells selected for high (GH3/B6/F10) and low (GH3/B6/D9) mERα expression. E2elicited rapid, concentration-dependent intracellular Ca2+concentration ([Ca2+]i) increases in the F10 subline. Lack of inhibition by thapsigargin depletion of intracellular Ca2+pools, together with abrogation of the response in Ca2+-free medium, suggested an extracellular source of Ca2+for this response. The participation of voltage-dependant channels in the E2-induced [Ca2+]iincrease was confirmed by the specific L-type Ca2+channel inhibitor nifedipine. For comparison, the D9 mERα-depleted subline was insensitive to steroid action via this signaling mechanism. [Ca2+]ielevation was correlated with prolactin (PRL) release in the F10 cell line in as little as 3 min. E2caused a much higher PRL release than KCl treatment (which caused maximal Ca2+elevation), suggesting that secretion was also controlled by additional mechanisms. Participation of mERα in these effects was confirmed by the ability of E2-peroxidase (a cell-impermeable analog of E2) to cause these responses, blockage of the responses with the ER antagonist ICI 182 780, and the inability of the E2stereoisomer 17α-E2to elicit a response. Thus rapid exocytosis of PRL is regulated in these cells by mERα signaling to specific Ca2+channels utilizing extracellular Ca2+sources and additional signaling mechanisms.
Inhibition of cardiac fibroblast proliferation and myofibroblast differentiation by resveratrol
Authors: Olson Erik R. , Naugle Jennifer E. , Zhang Xiaojin , Bomser Joshua A. , Meszaros J. Gary
Published: October 2004

Cardiac fibroblasts (CFs) regulate myocardial remodeling by proliferating, differentiating, and secreting extracellular matrix proteins. Prolonged activation of CFs leads to cardiac fibrosis and reduced myocardial contractile function. Resveratrol (RES) exhibits a number of cardioprotective properties; however, the possibility that this compound affects CF function has not been considered. The current study tests whether RES directly influences the growth and proliferation of CFs and differentiation to the hypersecretory myofibroblast phenotype. Pretreatment of CFs with RES (5–25 μM) inhibited basal and ANG II-induced extracellular signal-regulated kinase (ERK) 1/2 and ERK kinase activation. This inhibition by RES reduced basal proliferation and blocked ANG II-induced growth and proliferation of CFs in a concentration-dependent manner, as measured by [3H]leucine and [3H]thymidine incorporation, respectively. RES pretreatment attenuated ERK phosphorylation when CFs were stimulated with 0.2 nM epidermal growth factor (EGF), a concentration at which EGF-induced ERK activation over basal was similar to the phosphorylation induced by 100 nM ANG II. Akt phosphorylation in CFs was unaffected by treatment with either 100 nM ANG II or 25 μM RES. Pretreatment of CFs with RES also reduced both ANG II- and transforming growth factor-β-induced CF differentiation to the myofibroblast phenotype, indicated by a reduction in α-smooth muscle actin expression and stress fiber organization in CFs. This study identifies RES as an anti-fibrotic agent in the myocardium by limiting CF proliferation and differentiation, two critical steps in the pathogenesis of cardiac fibrosis.
Euler case for a general fourth‐order differential equation
Authors: Al-Hammadi A. S. A.
Published: October 2004

We deal with an Euler case for a general
fourth‐order equation and under this case, we obtain the
general formula for the asymptotic form of the solutions.
Classification of weak continuities and decomposition of continuity
Authors: Tong Jingcheng
Published: October 2004

We first introduce 20 weak forms of continuity, which are closely
related to 5 known weak forms of continuity. Then we classify
them into 9 groups and give 12 decompositions of continuity.
The terrestrial breeding biology of the ranid rock frog Nannophrys ceylonensis
Authors: Wickramasinghe  , Wassersug  , Oseen  , Kotagama
Published: October 2004

Nannophrys ceylonensis (Ranidae) is a terrestrial breeding anuran, found on wet vertical or near-vertical rock surfaces. Non-breeding adult males and females take refuge in separate crevices in the rock surfaces during the day and emerge at night to forage. Males can be polygynous; mating takes place inside crevices. Fathers exhibit paternal care for multiple clutches of eggs and guard eggs from predators. Paternal care of this species is obligatory; hatching success decreases without it. Females do not contribute to parental care. Males show nest site fidelity and defend territories against conspecifics. A scarcity of suitable nest sites may limit reproductive success in N. ceylonensis. Larvae hatch at Gosner stages 21-22 and leave their nests at stages 24-25 to live as truly terrestrial tadpoles, foraging on the rock surfaces near their natal nests.
Behavioral evidence for intraspecific signaling with achromatic and polarized light by cuttlefish (Mollusca: Cephalopoda)
Authors: Shashar Nadav , Vaughan Katrina , Loew Ellis , Boal Jean , Hanlon Roger , Grable Melissa
Published: October 2004

Intraspecific visual communication was studied quantitatively by testing the behavior of Sepia officinalis, the common cuttlefish, as senders and receivers of body pattern signals. These signals can be achromatic and/or linearly polarized and are produced by specialized dermal cells. Experiment 1 addressed whether the presence of conspecifics affected the visible, achromatic body patterns of males. These patterns tended to vary among conditions, suggesting limited sensitivity to audience. One set of body patterns varied with the number of conspecifics viewed while an uncorrelated set of body patterns varied with the sex of conspecifics viewed. Males showed high-contrast zebra banding when viewing another male, supporting previous studies of body patterns in male-male agonistic behavior. Experiment 2 addressed the relationship of polarized light patterns with visible body patterns of males and females, and tested whether senders modified their polarization patterns in response to conspecifics. Polarization patterning was only weakly associated with visible body patterns. Females showed more polarized body patterns than did males, but polarized patterns did not differ among conditions; thus, no sensitivity to audience by senders was found. Experiment 3 addressed whether conspecific receivers used information from polarized body patterns. Limited evidence was found for changes in the behavior of female but not male observers, suggesting that female receivers may use polarized patterns as a source of information about conspecifics. The information contained in polarization patterning may complement that contained in zebra patterning such that both males and females advertise their species, sex, location, and size to conspecific receivers.
Habitat and space use of European cuckoo females during the egg laying period
Authors: Taborsky Barbara , Honza Marcel , Vogl Wolfgang , Teuschl Yvonne , Taborsky Michael
Published: October 2004

In brood parasites, knowledge of spacing behaviour, habitat use and territoriality may reveal cues about how parasites find and use their hosts. To study the use of space and habitat of European cuckoos, Cuculus canorus, we radio-tagged 16 females during four consecutive reproductive seasons. We hypothesized that during the laying period cuckoo females should (1) use habitats selectively, and (2) attempt to monopolize potential egg laying areas to reduce competition for host nests. Our data are consistent with the first hypothesis: the use of pond edges compared to forest and transitional habitats was significantly greater than expected from the habitat availability in the total area and within individual female home ranges. All 26 directly observed egg layings and 27 nest visits without laying occurred at pond edges in nests of Acrocephalus spp. Females spent significantly more time at pond edges on egglaying days than on non-laying days. The second hypothesis was not supported: female home ranges overlapped similarly in all three major habitat categories of the potential egg laying areas, and only little aggression was observed between females. We discuss whether female cuckoos may lack territorial behaviour because they are not able to defend egg laying areas economically or because defence is not necessary due to sufficient availability of suitable host nests.
Effects of Corydalis yanhusuo and Angelicae dahuricae on Cold Pressor‐Induced Pain in Humans: A Controlled Trial
Authors: Yuan Chun‐Su , Mehendale Sangeeta R. , Wang Chong‐Zhi , Aung Han H. , Jiang Tingliang , Guan Xiongfei , Shoyama Yukihiro
Published: October 2004

Pain is considered the most common complaint worldwide for which patients seek treatment. Conventional analgesic agents play an important role in modern pain therapy, but they cause several adverse effects. Therefore, newer and better analgesics continue to be investigated. In this controlled clinical trial, the authors evaluated the analgesic effects of 2 herbal medicines, Corydalis yanhusuo and Angelicae dahuricae. They used the cold‐pressor test—a simple, reliable, and widely used model in humans—for induction of tonic pain. They demonstrated that after a single, oral administration of the extracts of C. yanhusuo and A. dahuricae, the pain intensity and pain bothersomeness scores significantly decreased (both P < .01). Dose‐related analgesic effect was also observed. Results from this study suggest that C. yanhusuo and A. dahuricae may have a potential clinical value for treating mild to moderate pain.
Lack of a Clinically Significant Effect of Zonisamide on Phenytoin Steady‐State Pharmacokinetics in Patients With Epilepsy
Authors: Levy René H. , Ragueneau‐Majlessi Isabelle , Garnett William R. , Schmerler Michael , Rosenfeld William , Shah Jaymin , Pan Wei‐Jian
Published: October 2004

This study was designed to measure the effect of the addition of zonisamide on phenytoin pharmacokinetics under steady‐state conditions in patients with epilepsy. Nineteen patients stabilized under phenytoin monotherapy were included in a 3‐center, open‐label, 1‐way drug interaction trial. Zonisamide was gradually increased to 400 mg/day, taken twice daily. Three pharmacokinetic profiles were performed: on days −7 and −1, to assess pharmacokinetic parameters of oral phenytoin administered alone, and on day 35, after 14 days of zonisamide treatment, to evaluate the effect of zonisamide on phenytoin pharmacokinetics and to characterize zonisamide pharmacokinetics in the presence of phenytoin. Fourteen patients completed the study; the coadministration of zonisamide and phenytoin was safe and well tolerated. Zonisamide did not significantly affect the mean Cmin, Cmax, AUC0–12, and CL/F of phenytoin measured before and after zonisamide administration. The pharmacokinetic measures of zonisamide in the presence of phenytoin were consistent with previous reports of induction of zonisamide metabolism by phenytoin.
Absence of a Clinically Relevant Interaction Between Etanercept and Digoxin
Authors: Zhou Honghui , Parks Virginia , Patat Alain , Le Coz Franck , Simcoe Donna , Korth‐Bradley Joan
Published: October 2004

Etanercept, a soluble recombinant human tumor necrosis factor receptor (TNFr), is effective and well tolerated in the treatment of rheumatoid arthritis, juvenile rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and psoriasis. The primary objective of this study was to investigate the potential pharmacokinetic and pharmacodynamic interaction between digoxin and etanercept at steady state. In a crossover, open‐label, nonrandomized, 3‐period study, 12 healthy male subjects received loading oral doses of digoxin 0.5 mg every 12 hours on day 1 and 0.25 mg every 12 hours on day 2, followed by a daily maintenance dose of 0.25 mg for a total of 27 days. Etanercept was administered as a twice‐weekly 25‐mg subcutaneous dose beginning on day 9 and continuing up to day 37 for a total of 9 doses. All ratios of maximum plasma concentration (Cmax) and area under the plasma concentration versus time curve (AUC) for pharmacokinetics of digoxin fell within the confidence interval of 0.8 to 1.25. Although not considered clinically relevant, the mean Cmax and AUC of etanercept were 4.2% and 12.5% lower, respectively, when etanercept was given with digoxin than when administered alone. There were no clinically relevant changes in the electrocardiogram (ECG) parameters, and adverse events did not increase when both drugs were combined. In conclusion, there is no clinically relevant interaction between etanercept and digoxin, and both drugs can be safely coadministered without the need for a dosage adjustment.
Pharmacokinetics of Articaine Hydrochloride in Tumescent Local Anesthesia for Liposuction
Authors: Grossmann Matthias , Sattler Gerhard , Pistner Hans , Oertel Reinhard , Richter Klaus , Schinzel Stefan , Jacobs Laurent‐Didier
Published: October 2004

The aim of the investigation was to assess the pharmacokinetic characteristics and safety of articaine HCl used in tumescent local anesthesia for liposuction. Maximum plasma concentrations of articaine HCl were observed from 136 to 264 ng/mL, on average, from 1.2 to 4.3 hours after the start of infiltration, depending on the area of liposuction. The average extent of absorption ranged from 827 to 2203 ng•h/mL. Average maximum plasma concentrations of articainic acid ranged from 1719 to 7292 ng/mL. The high articainic acid concentrations at 1 hour after the start of infiltration indicate that articaine HCl was hydrolyzed rapidly by esterases in tissue and plasma. Although up to 38.2 mg/kg body weight articaine HCl was applied, no cardiac side effects or symptoms of central nervous intoxication occurred. Articaine HCl provided a safe and sufficient analgesia for tumescent liposuction.
Population Pharmacokinetics of Clofarabine, a Second‐Generation Nucleoside Analog, in Pediatric Patients With Acute Leukemia
Authors: Bonate Peter L. , Craig Adam , Gaynon Paul , Gandhi Varsha , Jeha Sima , Kadota Richard , Lam Gilbert N. , Plunkett William , Razzouk Bassem , Rytting Michael , Steinherz Peter , Weitman Steve
Published: October 2004

The population pharmacokinetics of plasma clofarabine and intracellular clofarabine triphosphate were characterized in pediatric patients with acute leukemias. Traditional modelbuilding techniques with NONMEM were used. Covariates were entered into the base model using a forward selection significance level of .05 and a backwards deletion criterion of .005. Model performance, stability, and influence analysis were assessed using the nonparametric bootstrap and n‐1 jackknife. Simulations were used to understand the relationship between important covariates and exposure. A 2‐compartment model with weight (scaled to a 40‐kg reference patient) modeled as a power function on all pharmacokinetic parameters (0.75 on clearance‐related terms and 1.0 on volume‐related terms) was fit to plasma clofarabine concentrations (n = 32). White blood cell (WBC) count, modeled as a power function (scaled to a WBC count of 10 ± 103/μL), was a significant predictor of central volume with power term 0.128 ± 0.0314. A reference patient had a systemic clearance of 32.8 L/h (27% between‐subject variability [BSV]), a central volume of 115 L (56% BSV), an intercompartmental clearance of 20.5 L/h (27% BSV), and a peripheral volume of 94.5 L (39% BSV). Intracellular clofarabine triphosphate concentrations were modeled using a random intercept model without any covariates. The average predicted concentration was 11.6 ± 2.62 μM (80% BSV), and although clofarabine triphosphate half‐life could not be definitively estimated, its value was taken to be longer than 24 hours. The results confirm that clofarabine should continue being dosed on a per‐square‐meter or per‐body‐weight basis.