bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of slotting fees and trade promotions in shaping how tobacco is marketed in retail stores
Authors: Bloom Paul N
Published: July 2002

OBJECTIVE

To examine how the retail environment in which tobacco is sold has changed because of the slotting fees and trade promotions paid by the tobacco companies. Public policy options for dealing with this environment are also evaluated.

DATA SOURCES

A literature review, telephone interviews, and observation.

RESULTS

The tobacco companies have been dramatically increasing the volume of slotting fees and trade promotions they pay to retailers, creating a more tobacco friendly retail environment containing self service displays and ample point-of-sale advertising. Critics express concern that these payments have kept prices lower and more varied than they might be otherwise, created more opportunities for pilferage and underage selling, and provided more youth exposure to tobacco promotions. Public policy makers could either ban these payments, institute policies designed to mitigate their harmful effects, or leave the situation as it is, relying on enforcement of existing statutes as well as market forces to reduce harm. Actions that might mitigate harmful effects would include putting minimum retail prices on tobacco products, banning self service displays, requiring retailers to be licensed, and adding more warning signs at the point of sale.

CONCLUSION

Additional research is needed before determining the most appropriate public policy stance.
TO SELL OR NOT TO SELL? BEHAVIOR OF SHAREHOLDERS DURING PRICE COLLAPSES
Authors: ROEHNER BERTRAND M.
Published: July 2002

It is a common belief that the behavior of shareholders depends upon the direction of price fluctuations: if prices increase they buy, if prices decrease they sell. That belief, however, is more based on "common sense" than on facts. In this paper, we present evidence for a specific class of shareholders which shows that the actual behavior of shareholders can be markedly different. For instance, they may continue to buy despite a prolonged fall in prices or they may sell even though prices climb. A closer analysis shows that a substantial proportion of investors are more influenced by the "general social climate" than by actual price changes. The percentage of speculative investors who optimize their portfolio on a monthly basis can be estimated and turns out to be about 5 to 10%. The results presented in this paper can be of usefulness in order to test the assumptions or the results of market simulations and models.
MEMORY COST DUE TO ANTICIPATED BROADCAST
Authors: LOECHNER VINCENT , MONGENET CATHERINE
Published: July 2002

To get efficient solutions, parallelization techniques mainly focus on data alignment or on communication minimization. The efficiency of a parallel solution not only depends on the communication cost, but also on the memory cost. This paper mainly focus on a symbolic evaluation of the memory cost due to anticipated broadcast. This evaluation is conducted in the polytope model using Ehrhart polynomials, which express the number of integer points in a parameterized polytope.
ON FAIRLIE'S MOYAL FORMULATION OF M(ATRIX)-THEORY
Authors: HSSAINI M. , SEDRA M. B. , BENNAI M. , MAROUFI B.
Published: July 2002

Starting from the Moyal formulation of M theory in the large N-limit, we propose to reexamine the associated membrane equations of motion in ten dimensions formulated in terms of Poisson bracket. Among the results obtained, we rewrite the coupled first order Nahm equations into a simple form leading in turn to their systematic relation with SU (∞) Yang–Mills equations of motion. The former are interpreted as the vanishing condition of some conserved currents which we propose. We develop also an algebraic analysis in which an ansatz is considered and find an explicit form for the membrane solution of our problem. Typical solutions known in literature can also emerge as special cases of the proposed solution.
UA(1) SYMMETRY BREAKING AND THE SCALAR SECTOR OF QCD
Authors: NAPSUCIALE M. , RODRIGUEZ S.
Published: July 2002

It is shown that most of the unusual properties of the lowest lying scalar (and pseudoscalar) mesons can be understood, at the qualitative and quantitative level, on the basis of the breakdown of the UA(1) symmetry coupled to the vacuum expectation values of scalars by the spontaneous breaking of chiral symmetry.
SUPERSTRINGS, GAUGE FIELDS AND BLACK HOLES
Authors: BAAQUIE BELAL E. , KWEK L. C.
Published: July 2002

There has been spectacular progress in the development of string and superstring theories since its inception thirty years ago. Development in this area has never been impeded by the lack of experimental confirmation. Indeed, numerous bold and imaginative strides have been taken and the sheer elegance and logical consistency of the arguments have served as a primary motivation for string theorists to push their formulations ahead. In fact the development in this area has been so rapid that new ideas quickly become obsolete. On the other hand, this rapid development has proved to be the greatest hindrance for novices interested in this area. These notes serve as a gentle introduction to this topic. In these elementary notes, we briefly review the RNS formulation of superstring theory, GSO projection, D-branes, bosonic strings, dualities, dynamics of D-branes and the microscopic description of Bekenstein entropy of a black hole.
RENORMALIZATION OF HAMILTONIAN
Authors: ALEXANIAN GARNIK G. , MORENO E. F.
Published: July 2002

In this talk we describe a novel method for the renormalization of the Hamiltonian operator in Quantum Field Theory in the spirit of the Wilson renormalization group1. By a series of unitary transformations that successively decouple the high-frequency degrees of freedom and partially diagonalizes the high-energy part, we obtain the effective Hamiltonian for the low energy degrees of freedom. Using this technique we study λϕ4 theory at two loops and QED and Yang-Mills theory at one loop.
THE HIGGS AS A SUPERSYMMETRIC PARTNER WITH A NEW INTERPRETATION OF YUKAWA COUPLINGS
Authors: ALLEN ROLAND E.
Published: July 2002

An unconventional version of supersymmetry leads to the following highly teatable predictions: (1) the Higgs boson has an R-parity of -1, so it can only be produced as one member of a pair of superpartners. (2) The only superpartners are scalar bosons, so neutralinos etc. do not exist. (3) The most likely candidate for cold dark matter is therefore a sneutrino. (4) The Higgs and other bosonic superpartners have an unconventional equation of motion. These predictions are associated with new interpretations of Yukawa couplings, supersymmetry, gauge fields, and Lorentz invariance.
ON THE ASYMPTOTIC BEHAVIOR OF THE PHOTON PROPAGATOR IN QUANTUM ELECTRODYNAMICS
Authors: ALTENBERGER ANDRZEJ R. , DAHLER JOHN S.
Published: July 2002

A new renormalization group method is used to calculate the photon propagator in the high four-momentum regime. The assumption that this propagator is a self-similar object leads directly to a functional equation of evolution involving an invariant charge (effective coupling function) which, in turn, is a functional of the propagator. Numerical results produced by this theory depend on a single unknown, namely, the scale in which the four-momentum k is measured. Calculations are presented for several values of this scale. From these it is concluded that the transverse photon propagator behaves asymptotically as D⊥(k)~k2(λ-1) with the value of λ (the anomalous dimension) falling in the range (0.12, 1).
STRIPE AND SPIN DYNAMICS IN HOLE DOPED La2NiO4, La2CuO4, Bi2Sr2CaCu2O8 AND ELECTRON DOPED Nd1.85Ce0.15CuO4 SEEN BY NUCLEAR RESONANCE
Authors: BROM H. B. , ABU-SIEKAH I. M. , BAKHAREV O. , BERNAL O. O. , KES P. H. , NIKOLAEV E. G. , TEITEL'BAUM G. B. , NUGROHO A. A. , MENOVSKY A. A. , ZAANEN J.
Published: July 2002

Using new resonance results, we investigate the relation between the charge and spin ordering features seen by a.o. neutron scattering and ARPES, and the NMR/NQR signal intensities (wipe-out effects), relaxation rates and line shapes in hole doped La 2 NiO 4, La 2 CuO 4, Bi 2 Sr 2 CaCu 2 O 8 and electron doped NdCeCuO 4. We indicate what is understood and which questions are still open, with especially a focus on the observation that the wipe out effects happen in both hole and electron doped systems and continue down to the lowest measured temperatures. The latter feature might be the signature of a glassy dynamics of an entirely new kind, associated with the special nature of stripe order.
Exact Ground-State Properties and Phase Transitions within One-dimensional Hubbard Model in Magnetic Field
Authors: Yang C. , Kocharian A. N. , Chiang Y. L.
Published: July 2002

The phase diagram, the Bethe-ansatz ground-state properties, including the chemical potential μ, the spin (magnetic) and charge susceptibilities, are calculated within the one-dimensional Hubbard model in entire range of interaction strength (-∞< U/t<+∞), magnetic field (h≥ 0) and all electron concentrations (0≤n≤1). The continuous and smooth variation of μ with n and h in the vicinity of n=1 points on the gapless character of charge excitations at U<0 and provides rigorous upper and lower bounds for μ. The spin (magnetic) susceptability χ at half-filling changes discontinuously as U→0 and is strongly enhanced by electron repulsion, comparing with that of the non-interactig case. The compressibility κ ch increases with n at U<0 and shows non-monotonous behavior with a dramatic increase at U>0. Variations of κ ch -1 in both repulsive and attractive cases qualitatively well reproduces corresponding behavior of charge stiffness.
NEW INSIGHT INTO THE INTEGER QUANTUM HALL EFFECT
Authors: SRIVASTAVA VIPIN
Published: July 2002

By considering the degeneracies of the localized and extended states separately we have investigated the integer quantum Hall effect (IQHE) in terms of fraction of extended states in a Landau subband. The IQHE is found to manifest itself as saw-tooth oscillations in the number density of the extended electrons as a function of magnetic field. Preliminary results of an experiment are also presented that support this picture. It is found that contrary to the traditional theoretical belief, the extended states form a non-vanishing fraction of the states in a Landau subband. Significantly it is shown that if this was not so, the IQHE would not arise in the first place. This result is relevant in connection with the long standing question of nature of transition between plateaus, and also the recent discovery of intriguing electron density driven metal–insulator transition in two-dimensional systems. The results also show that extended states float up in energy in addition to being systematically destroyed as the magnetic field is reduced, and that the system can become completely localized at a nonzero magnetic field.
EXOTIC PLASMA AS CLASSICAL HALL LIQUID
Authors: DUVAL C. , HORVÁTH Z. , HORVÁTHY P. A.
Published: July 2002

A non-relativistic plasma model endowed with an "exotic" structure associated with the two-parameter central extension of the planar Galilei group is constructed. Introducing a Chern–Simons statistical gauge field provides us with a self-consistent system; when the magnetic field takes a critical value determined by the extension parameters, the fluid becomes incompressible and moves collectively, according to the Hall law.
EXCITON DYNAMICS OF ORTHORHOMBIC PHASE PbI2 EMBEDDED IN PbI2-PbBr2 MIXED CRYSTALS
Authors: TAKEDA J. , SAKAMOTO T. , ARAI T. , KURITA S.
Published: July 2002

Reflection, time-integrated and time-resolved luminescence spectra have been measured in PbI 2(1-x) Br 2x(x≥0.5) mixed crystals in order to elucidate the excitonic properties and relaxation processes of orthorhombic phase PbI 2 embedded in the mixed crystals. The crystal structure of PbI 2(1-x) Br 2x above x=0.5 is orthorhombic and an observed new reflection peak (~2.5 × 104 cm -1) above x=0.5 is due to an excitonic state of orthorhombic phase PbI 2. On the excitation energy above 2.5 × 104 cm -1, a broad luminescence band with a large Stokes shift from the reflection peak was observed. This luminescence band is attributed to a self-trapped exciton state. The decay of the luminescence has two components. Based on an atomic excitation picture, the shorter decay component (≤10 ns ) is attributed to the allowed transition from 3P1 to 1S0. On the other hand, the longer decay component (~3 μ s ) might be due to the forbidden transition from 3P0 to 1S0.
DECOMPOSITION KINETICS OF Cu-10aT%Co ALLOY STUDIED BY IN-SITU ELECTRICAL RESISTANCE MEASUREMENT
Authors: PENG P. , JIN Z. H. , LU K. , HU Z. Q.
Published: July 2002

The spinodal decomposition processes in the rapidly solidified Cu-10aT%Co alloy aged at several temperatures have been investigated using an in-situ electrical resistance measurement method combining a slowly scanning x-ray diffraction technique. Based on the Cahn-Hilliard theory, the time-dependences of amplification factor of the concentration modulation R(β) at different aging temperatures were calculated, and the Co atomic concentration of Co-rich region and Co-depleted region in the aged alloy were also deduced. The results showed that the evolution of composition modulation in microstructure in Cu-10aT%Co alloy can be monitored and characterized by an in-situ electrical resistance measurement method if only the degree of phase decomposition at some aging temperature and aging time had been previously deteced.
SURFACE AND INTERFACE PROPERTIES OF ION IMPLANTED 4H-SILICON CARBIDE
Authors: CHANG W. Y. , FENG Z. C. , LIN J. , YAN F. , ZHAO J. H.
Published: July 2002

A series of ion-implanted 4H-SiC epilayers, Aluminum (Al) – Carbon (C) co-implanted and Al single implanted, have been studied by micro-Raman scattering, Fourier transform infrared (FTIR), and UV-Visible (200-1100 nm) optical transmission (OT) measurements. The damage and amorphization of SiC layer by ion-implantation, and the elimination or suppression of the implantation induced amorphous layer via high temperature annealing are evidenced. The recovery of the crystallinity and the activation of the implant acceptors are confirmed. Theoretical simulations on the spectroscopic features, for FTIR reflectance spectra, are performed based upon the structural model. The results from different ion implantation conditions are compared. This work also provides a non-destructive and convenient way to investigate the effects of ion implantation/annealing on SiC materials.
ELIASHBERG EQUATIONS AND THE PHENOMENOLOGY OF FIELD-EFFECT-DOPED C60
Authors: UMMARINO G. A. , GONNELLI R. S. , DAGHERO D.
Published: July 2002

In a recent paper [J. H. Schön, Ch. Kloc, R. C. Haddon and B. Batlogg, Nature408, 549 (2000)] C 60 doped with holes by application of an intense electric field was found to superconduct at remarkably high temperature. In this paper we show that the observed dependence of T c on doping can be reproduced by solving the (four) s-wave Eliashberg equations in the case of a finite, non-half-filled energy band, with the only initial hypothesis that the Coulomb pseudopotential depends on the filling in a very simple and plausible way. The experimental data are reproduced by using very reasonable values of the physical parameters involved. We also show that the application of the same approach to new experimental data [ J. H. Schön, Ch. Kloc and B. Batlogg, Science293, 2432 (2001)] also gives good results.
DEFORMATION QUANTIZATION: IS C1 NECESSARILY SKEW?
Authors: FRONSDAL CHRISTIAN
Published: July 2002

Deformation quantization (of a commutative algebra) is based on the introduction of a new associative product, expressed as a formal series, [Formula: see text]. In the case of the algebra of functions on a symplectic space the first term in the perturbation is often identified with the antisymmetric Poisson bracket. There is a wide-spread belief that every associative *-product is equivalent to one for which C1(f,g) is antisymmetric and that, in particular, every abelian deformation is trivial. This paper shows that this is far from being the case and illustrates the existence of abelian deformations by physical examples.
TEMPERATURE PROGRAMMED OXYGEN EVOLUTION AND ELECTRICAL CONDUCTIVITY OF A NEW SERIES OF FLUORITE COMPOSITIONS IN La2-xPrxO3+y (1≤x≤2) SYSTEM
Authors: RAJENDRAN M. , KRISHNA M. GHANASHYAM , BHATTACHARYA A. K.
Published: July 2002

Temperature programmed oxygen evolution (TPD) and electrical conductivity of a new series of fluorite compositions in La 2-x Pr x O 3+y(1≤x≤2) system have been investigated. For x=2, oxygen evolution occurs at three distinct steps, whereas for x≤1.8, oxygen evolution occurs only in two steps and for x=1 it becomes negligible. A decrease in the Pr-content in the fluorite compositions lowers the TPD peak intensity. The samples resorb oxygen on annealing at 650° C in flowing oxygen and cooling the samples to room temperature revealing the reversible oxygen uptake and release feature. The electrical conductivity increases as a function of Pr-content in this series. For x≤1.8, the temperature dependent conductivity shows breaks at two temperature regions and the magnitude of the break is pronounced in Pr-rich compositions. Also, the activation energy decreases as the Pr-content is increased in this series. The present results suggest that the fluorite compositions in this system might have potential as catalysts to store/transport/release oxygen reversibly.
Abrikosov Monopole Vortices and Their Images in a Circular Josephson Tunnel Junction
Authors: Lisitskii M. P. , Cristiano R. , Nappi C. , Esposito E. , Frunzio L. , Gubankov V. N.
Published: July 2002

We present the results of a numerical simulation of the dependence of the Josephson critical current on the parallel magnetic field in the presence of a large number of Abrikosov 'monopole' vortices for the case of a circular junction. The influence of the junction edge on the distribution of the magnetic field of each vortex was taken into account by introducing image monopole vortices. Our simulations show that the dependence of the Josephson critical current on the parallel magnetic field (the Ic vs Hpar dependence) critically depends on the existence of a vortex located near the center of the junction. The simulation data are compared with experiments made on circular Nb/Al-AlOx/Nb junctions. A good agreement has been found between calculated and Ic vs Hpar dependences measured after the application of a perpendicular magnetic field.
ELECTRONIC AND STRUCTURAL PROPERTIES OF C36 MOLECULE
Authors: YU XIAOQING , WU CONGJUN , WANG CHUI-LIN , SU ZHAO-BIN
Published: July 2002

The extended SSH model and Bogoliubov–de–Gennes (BdeG) formalism are applied to investigate the electronic properties and stable lattice configurations of C 36. We focus the problem on the molecule's unusual D6h symmetry. The electronic part of Hamiltonian without Coulomb interaction is solved analytically. We found that the gap between HOMO and LUMO is small due to the long distance hopping between the 2nd and 5th layers. The charge densities of HOMO and LUMO states are mainly distributed in the two layers, that causes a large splitting between the spin triplet and singlet excitons. The differences of bond lengths, angles and charge densities among molecule and polarons are discussed.
KINETIC INDUCED PHASE TRANSITION
Authors: TRIMPER STEFFEN
Published: July 2002

An Ising model with local Glauber dynamics is studied under the influence of additional kinetic restrictions for the spin-flip rates depending on the orientation of neighboring spins. Even when the static interaction between the spins is completely eliminated and only an external field is taken into account the system offers a phase transition at a finite value of the applied field. The transition is realized due to a competition between the activation processes driven by the field and the dynamical rules for the spin-flips. The result is based on a master equation approach in a quantum formulation.
SYMMETRY AND SYMMETRY BREAKING: AN ALGEBRAIC APPROACH TO THE GENETIC CODE
Authors: HORNOS JOSÉ EDUARDO M. , HORNOS YVONE M. M. , FORGER MICHAEL
Published: July 2002

We give a comprehensive review of the algebraic approach to the genetic code originally proposed by two of the present authors, which aims at explaining the degeneracies encountered in the genetic code as the result of a sequence of symmetry breakings that have occurred during its evolution. We present the relevant background material from molecular biology and from mathematics, including the representation theory of (semi) simple Lie groups/algebras, together with considerations of general nature.
PRECURSOR OF ANTIFERROMAGNETIC BANDS IN THE HALF-FILLED TWO-DIMENSIONAL HUBBARD MODEL
Authors: KYUNG BUMSOO
Published: July 2002

We study the half-filled two-dimensional Hubbard model in the intermediate coupling regime. As temperature is decreased for a two-dimensional half-filled band, two-dimensional critical fluctuations give rise to a strong local maximum in | Im Σ(k F , ω)| at ω=0, leading to a split peak with a pseudogap inside in the spectral function and the density of states. The calculated energy dispersion is in good agreement with that of spin density wave approximation.
NEW WAY TO ACHIEVE SYNCHRONIZATION IN SPATIALLY EXTENDED SYSTEMS
Authors: GUPTA BIKASH C. , SREERAM P. A. , LEE S. B.
Published: July 2002

We study the spatio-temporal behavior of simple unidirectionally coupled map lattices with periodic boundary conditions. The local dynamics is governed by two maps, the sine circle map and the logistic map. It is found that even though the spatial behavior is irregular for the regularly coupled (nearest-neighbor coupling) system, the spatially synchronized (sometimes chaotically synchronized) as well as periodic solution may be obtained by the rearrangement of only three nearest-neighbor couplings.
SURFACE AND VOLUME CRYSTALLIZATION OF METALLIC GLASS (Ni50Zr50)99.9P0.1 AS INVESTIGATED BY EXOELECTRON EMISSION (EEE) AND DIFFERENTIAL THERMAL ANALYSIS (DTA)
Authors: GÓRECKI CZ. , GÓRECKI T. , SZYMURA S.
Published: July 2002

Surface and volume crystallization of amorphous, melt-quenched (Ni50Zr50)99.9P0.1 alloy has been investigated by measurements of the temperature dependencies of the intensity of photostimulated exoelectron emission (EEE) and by differential scanning calorimetry (DSC). A comparison of these dependencies enables one to assess the tendency of the investigated materials to premature surface crystallization. For the (Ni50Zr50)99.9P0.1 alloy the surface crystallization occurs at temperatures distinctly lower than that for the crystallization in bulk. The activation energy for the surface crystallization, determined by the Ozawa method, i.e. from the shift of EEE peak corresponding to the surface crystallization on changing the heating rate, is also much lower than that for the volume crystallization.
A SHAPE CLASSIFIER BY USING IMAGE PROJECTION AND A NEURAL NETWORK
Authors: HOU TUNG-HSU (TONY) , PERN MING-DER
Published: July 2002

In this research a computer vision-based shape recognition system which combines an image projection and the back propagation neural network is proposed. The system uses the image projection and features of the projection histogram to represent the shape, and uses the back propagation neural network to classify the shape. In this research, a fast normalization scheme is developed which is especially designed for image projection and can also find the same projection axis no matter what the object's orientation. Therefore, the proposed system can be invariant to scale, translation, and orientation variations. This research finds that the direct representation scheme of the back propagation neural net has better accuracy than the binary coding representation scheme. This research also finds that the proposed system's classification accuracy is greater than 98.8% and its processing speed is also very fast. Therefore, the proposed system is feasible for use in shape classification, in practice.
CONTROL OF HUMAN ATRIAL FIBRILLATION
Authors: DITTO W. L. , SPANO M. L. , IN V. , NEFF J. , MEADOWS B. , LANGBERG J. J. , BOLMANN A. , McTEAGUE K.
Published: July 2002

Chaos control has been applied to control atrial fibrillation in humans. Results are presented on the application and evaluation of chaos control for slowing and regularizing local electrical activation of the right atrium of humans during induced atrial fibrillation.
DELAYED FEEDBACK CONTROL OF A PACED EXCITABLE OSCILLATOR
Authors: BLEICH MICHAEL E. , SOCOLAR JOSHUA E. S.
Published: July 2002

A simple numerical experiment on Fitzhugh–Nagumo equations demonstrates that time-delay feedback methods can stabilize regular behavior in a paced, excitable oscillator without using large applied pulses. The method is robust against slow variations in the pacing rate and can be used to track an orbit into a parameter regime where it is unstable. Moreover, the method requires no information about the desired orbit other than period, which is determined directly by the observation of the pacing signal. Results are presented for feedback stabilization of a nonspiking orbit in the rapid pacing regime.
STABILIZING UNSTABLE PERIODIC ORBITS OF CHAOTIC SYSTEMS WITH UNKNOWN PARAMETERS
Authors: TIAN YU-PING , YU XINGHUO
Published: July 2002

A novel adaptive time-delayed control method is proposed for stabilizing inherent unstable periodic orbits (UPOs) in chaotic systems with unknown parameters. We first explore the inherent properties of chaotic systems and use the system state and time-delayed system state to form an asymptotically stable invariant manifold so that when the system state enters the manifold and stays in it thereafter, the resulting motion enables the stabilization of the desired UPOs. We then use the model following concept to construct an identifier for the estimation of the uncertain system parameters. We shall prove that under the developed scheme, the system parameter estimates will converge to their true values. The effectiveness of the method is confirmed by computer simulations.
TURBULENCE CONTROL AND SYNCHRONIZATION AND CONTROLLABLE PATTERN FORMATION
Authors: XIAO J. H. , HU G. , GAO J. H.
Published: July 2002

Pattern and turbulence control and synchronization are investigated by considering the model of the complex Ginzburg–Landau equation. It is shown that in fully-developed turbulence region, when a large number of positive Lyapunov exponents exists, in the presence of a large gradient force, we can drive the system to various desired spatiotemporal patterns, and control and synchronize violent turbulence by applying convenient boundary control technique.
GENERALIZED DECIMATION INVARIANT SEQUENCES IN DIMENSION N
Authors: BARBÉ A. , VON HAESELER F.
Published: July 2002

We generalize the concept of one-dimensional decimation invariant sequences, i.e. sequences which are invariant under a specific rescaling, to dimension N. After discussing the elementary properties of decimation-invariant sequences, we focus our interest on their periodicity. Necessary and sufficient conditions for the existence of periodic decimation invariant sequences are presented.
THERE ARE ONLY FINITELY MANY 3-SUPERBRIDGE KNOTS
Authors: JEON CHOON BAE , JIN GYO TAEK
Published: July 2002

Although there are infinitely many knots with superbridge index n for every even integer n≥4, there are only finitely many knots with superbridge index 3.
REAL TUNNELING AND BLACK HOLE CREATION
Authors: WU ZHONG CHAO
Published: July 2002

We discuss the Hawking theory of quantum cosmology with regard to approximation at the lowest order of the Planck constant. At this level, the quantum scenario will be reduced to its classical evolutions in real and imaginary times. We restrict our attention to the so-called real tunneling case. It can be shown that, even at this level, there still exist some quantum effects, the classical field equation may not hold at the transition surface. One can introduce the concept of constrained gravitational instanton. It may play some important role in the scenario of black hole creation in the inflationary background at the Planckian era of the universe. From the constrained gravitational instanton, the real tunneling can occur through different ways. Consequently, it will lead to the creation of different parts of the black hole spacetime in the de Sitter background. The global aspects of the black hole creation are discussed.
RENORMALIZING ROUGH-SURFACE SCATTER
Authors: MCDANIEL SUZANNE T.
Published: July 2002

Exact and approximate solutions to the rough-surface scattering problem are compared to examine the predictive capability of renormalized surface scattering theory. Numerical results are presented for scattering from one-dimensional rough periodic surfaces on which the Dirichlet (acoustic pressure-release) and Neumann (acoustically rigid) boundary conditions are imposed. For scattering from Dirichlet surfaces, the predictions of renormalized scattering theory are found to provide better agreement with exact solutions than perturbation theory. For this boundary condition, many convergent approximations exist, and the small-slope approximation is found to yield an improvement to renormalization. For the Neumann boundary condition, renormalization provides good agreement with exact solutions for scattering from slightly rough surfaces. The Kirchhoff approximation, the only other convergent approximation applicable to the Neumann problem, provides agreement with exact solutions for scattering from moderately rough surfaces for angles of scatter and incidence far from grazing.
ON A GENERALIZED DUAL PROCESS SOFTWARE RELIABILITY GROWTH MODEL
Authors: ZEEPHONGSEKUL PANLOP , BODHISUWAN WINAI
Published: July 2002

A significant number of software reliability growth models (SRGMs) have been proposed in the literature over the past three decades or so. Most of these models ignored the possibility of imperfect debugging with subsequent introduction of new errors into the software system. In this paper, we present an SRGM which consists of a dual process of debugging followed by introduction of errors in the event of an imperfect debugging. The model also allows for the process to be repeated over several stages. The reliability growth of this model is investigated and is shown to exhibit either an exponential or S-shaped curve. Finally, some reliability measures associated with the SRGM are presented together with illustrative numerical examples.
MÖSSBAUER STUDY OF STRUCTURAL–CHEMICAL TRANSFORMATION IN TWO-DIMENSIONAL IRON–OXYGEN NANOSTRUCTURES IN THE COURSE OF TRANSPORT REDUCTION
Authors: SMIRNOV V. M. , VORONKOV G. P. , SEMENOV V. G. , POVAROV V. G. , MURIN I. V.
Published: July 2002

Structural–chemical transformations of quasi-two-dimensional iron–oxygen nanostructures occurring at transport reduction were studied using NGR spectroscopy. It has been found that isolated iron–oxygen groups [i.e. groups containing iron and oxygen atoms: ≡Si–O–Fe(OH)2 and (≡Si–O–)2–FeOH] forming surface monolayers were not reduced at T = 400–600° C because of their covalent bonding with the silica surface. Reduction of iron oxide microparticles (microstructures) at T ≥ 600°C C resulted in the formation of metal iron in the form of α-Fe. It has been revealed that in the course of transport reduction (TR) of the samples with deposited monolayers (one or four monolayers) at T ≥ 600° C bulk phases of iron silicate and metal iron were formed. It has also been shown that the features of structural–chemical transformations of supported iron–oxygen nanolayers were in relation with the specific character of phase formation within nanoscale structures.
INSULATING OXIDES IN LOW DIMENSIONALITY: A THEORETICAL REVIEW
Authors: NOGUERA CLAUDINE
Published: July 2002

In the light of recent studies, we summarize our present theoretical understanding of insulating oxides in low dimensionality, including unsupported clusters, planar or stepped surfaces and ultrathin films. We review the various theoretical approaches, their efficiency in calculating ground and excited state properties, and their applications to the present systems. We discuss the forces at work which determine the atomic structure around under-coordinated atoms (equilibrium geometries of very small clusters, bond lengths, relaxation and rumpling at surfaces), the energetics associated with low dimensionality (surface energies and mean cohesion energy in clusters), the electronic properties, such as electron distribution, magnetic interactions and ordering, and electronic excitations (ionization potentials, electron affinity, quasiparticle spectra, d → d and charge transfer excitations).
CHARACTERIZATION OF ALUMINUM SURFACES AFTER DIFFERENT PRETREATMENTS AND EXPOSURE TO SILANE COUPLING AGENTS
Authors: KONO M. , SUN X. , LI R. , WONG K. C. , MITCHELL K. A. R. , FOSTER T.
Published: July 2002

X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) have been used to characterize surfaces of aluminum which have been pretreated by mechanical polishing, acid etching and alkaline etching, as well as given subsequent exposures to air and water. These surfaces can differ markedly with regard to their chemical compositions and topographical structures. Characterizations of these surfaces after exposures to three organosilanes, γ-GPS, BTSE and γ-APS, indicate that the amount of silane adsorbed in each case shows a tendency to increase both with the number of OH groups detected at the oxidized aluminum and with the surface roughness. The XPS data are consistent with the adhesion of γ-APS occurring through H bonding, especially via NH3+ groups.
A REVIEW OF QUANTITATIVE STRUCTURAL DETERMINATIONS OF ADSORBATES ON METAL OXIDE SURFACES
Authors: DANIELS B. G. , LINDSAY R. , THORNTON G.
Published: July 2002

This review summarises the published literature concerning quantitative experimental determinations of adsorbate geometry in the monolayer regime and below on metal oxide surfaces. Studies utilising either single crystals or highly ordered thin films as substrates are included.
SODIUM AND CHLORINE COADSORPTION ON Si(100)
Authors: KAMARATOS M. , PAPAGEORGOPOULOS C. A.
Published: July 2002

In this paper we study the adsorption of molecular chlorine on the Si(100)(2 × 1) surface and its interaction with sodium at room and elevated temperature in an ultrahigh vacuum. Cl is deposited dissociatively on the surface and forms SiCl 2 and SiCl 4. During Na deposition on the Cl-covered Si(100) surface, the substrate participates to a NaSiCl 2 compound formation, whereas Cl deposition on Na-covered Si(100) leads to NaCl formation, which is grown with the (100) plane parallel to the surface. After the completion of the NaCl formation, the excess Cl interacts with the substrate and forms Si–Cl compounds. The presence of Na on the surface prevents partly the chlorination of Si, depending on the amount of Na. At elevated temperatures, the NaCl dissociates according to the equation 2 NaCl + Si → Na 2 Cl + SiCl and desorbs.
EFFECTIVE BAND MODEL OF GIANT MAGNETORESISTANCE
Authors: WARDA K. , WOJTCZAK L. , BALDOMIR D. , PEREIRO M.
Published: July 2002

We consider the transport properties in magnetic multilayers for electronic current in the plane of the surfaces. The model is based on the effective s-band construction for the multilayer consisting of the metallic spacer and two ferromagnetic layers characterized by s–d coupling. We discuss the quasielectron spectrum in its effective mass approximation, with the perturbation taken into account by the effective potential, which also includes the interface contributions. We find the energy dispersion and the Fermi level for the effective s-band common for electrons in the whole sample. The results are equivalent in fact to those obtained within the Hoon–Falicov model, but they seem to us much simpler and more transparent for their extensions and applications.
LOW ENERGY ELECTRON MICROSCOPY STUDIES OF THE GROWTH OF GaN ON 6H–SiC(0001)
Authors: PAVLOVSKA A. , BAUER E.
Published: July 2002

The experimental possibilities and limitations of the study of the MRE growth of GaN on 6H-SiC(0001) in a low energy electron microscope are discussed. Results illustrating these possibilities and limitations are presented. We disagree with the interpretation given in a recent report on some of the results. In this paper, we present our own interpretation of the experimental data and provide the reasons why the earlier interpretation is incorrect.
O–Cu(001): I. BINDING THE SIGNATURES OF LEED, STM AND PES IN A BOND-FORMING WAY
Authors: SUN CHANG Q.
Published: July 2002

This work consists of two sequential parts, which review the advances in uncovering the capacity of VLEED, STM and PES in revealing the nature and kinetics of oxidation bonding and its consequences for the behavior of atoms and valence electrons at a surface; and in quantifying the O–Cu(001) bonding kinetics. The first part describes the model in terms of bond making and its effect on the valence DOS and on the surface potential barrier (SPB) for surfaces with chemisorbed oxygen. One can replace the hydrogen in a H 2 O molecule with an arbitrary less electronegative element and extend the M 2 O to a solid surface with Goldschmidt contraction of the bond length, which formulates a specific oxidation surface with identification of atomic valences and their correpondence to the STM and PES signatures. As consequences of bond making, oxygen derives foou additional DOS features in the valence band and above, i.e. O–M bonding (~ -5 eV), oxygen nonbounding lone pairs (~ - 2 eV), holes (≤ EF ), and antibonding metal dipoles (≥ EF ), in addition to the hydrogen-bond-like formation. The evolution of O -1 to O -2 transforms the CuO 2 pairing off-centered pyramid in the c(2× 2)-2 O -1 into the CU 3 O 2 pairing tetrahedron in the [Formula: see text] phase on the Cu(001) surface. The new decoding technique has enabled the model to be justified and hence the capacity of VLEED, PES and STM to be fully uncovered in determining simultaneously the bond geometry, the SPB, the valence DOS, and their interdependence.
TREATMENT OF TRIGGER FINGERS BY INJECTION OF METHYLPREDNISOLONE ACETATE AND LIDOCAINE (DEPO-MEDROL®)
Authors: Hage J. Joris , Munting Jaap D.K.
Published: July 2002

Thirty-six adult patients with 44 trigger fingers of less than four months' duration entered a prospective study on the efficiency of treatment with local injections of a combination of corticosteroids and lidocaine. From this study it may be concluded that the short-term success rate (93%) of one to three injections of methylprednisolone and lidocaine 2% (Depo-Medrol®) is comparable to that achieved by surgical or percutaneous tenolysis. At one year of follow-up, this success rate still amounted to 86%. In our hands, this therapy is without complications or side effects.
UNIFORM LYAPUNOV EXPONENTS ARE REALISED BY ERGODIC INVARIANT MEASURES
Authors: CRAUEL HANS
Published: July 2002

Given a differentiable random dynamical system on a finite-dimensional differentiable manifold with a compact random invariant set, we show that there exists an ergodic invariant measure, supported by the invariant set, such that the leading Lyapunov exponent associated with this invariant measure equals the uniform Lyapunov exponent with respect to the invariant set. This is extended to sums of Lyapunov exponents and to the Lyapunov dimension of the set.
THE IMPLEMENTATION OF EMS IN CONSTRUCTION FIRMS: CASE STUDY IN HONG KONG
Authors: TSE RAYMOND Y. C.
Published: July 2002

It has been increasingly recognised that construction activity imposes external costs to the environment. This paper aims to review the benefits and major problems in the implementation of ISO 14000 EMS in the Hong Kong construction industry. This study surveyed major construction firms in Hong Kong to uncover the hindrance factors contributing to the low adoption of ISO 14000. Based on the findings, this paper identifies and ranks the perceived order which hinders the construction firms' adoption of ISO 14000. The case study in Hong Kong serves as a reference point for understanding the problems in the implementation of ISO 14000 in other countries.

Specifically, this study found that the four major obstacles to ISO 14000 implementation are: lack of government pressure; lack of client requirement/supports; expensive implementation cost; and sub-contracting systems, which create difficulties in managing the EMS. Since the government is a very dominant client, the extent to which the Government wishes to restrict its choice of tenderer to those firms that have an environmental management system in place, will demonstrate its commitment to environmentally responsible operations. The public sector clients play a critical role in driving the construction industry to improve its operations through contractual requirements. Education of the end-users is also important to create market demand for environmentally friendly construction. To an extent, professional institutions and other industry bodies can help to instill a greater sense of accountability among industry participants by stipulating acceptable standards of behaviour and establishing a supportive regulatory framework.
High-speed switch scheduling for local-area networks
Authors: Anderson Thomas E. , Owicki Susan S. , Saxe James B. , Thacker Charles P.
Published: July 2002

Current technology trends make it possible to build communication networks that can support high-performance distributed computing. This paper describes issues in the design of a prototype switch for an arbitrary topology point-to-point network with link speeds of up to 1 Gbit/s. The switch deals in fixed-length ATM-style cells, which it can process at a rate of 37 million cells per second. It provides high bandwidth and low latency for datagram traffic. In addition, it supports real-time traffic by providing bandwidth reservations with guaranteed latency bounds. The key to the switch's operation is a technique called
parallel iterative matching
, which can quickly identify a set of conflict-free cells for transmission in a time slot. Bandwidth reservations are accommodated in the switch by building a fixed schedule for transporting cells from reserved flows across the switch; parallel iterative matching can fill unused slots with datagram traffic. Finally, we note that parallel iterative matching may not allocate bandwidth fairly among flows of datagram traffic. We describe a technique called
statistical matching
, which can be used to ensure fairness at the switch and to support applications with rapidly changing needs for guaranteed bandwidth.
An empirical study of algorithms for point-feature label placement
Authors: Christensen Jon , Marks Joe , Shieber Stuart
Published: July 2002

A major factor affecting the clarity of graphical displays that include text labels is the degree to which labels obscure display features (including other labels) as a result of spatial overlap. Point-feature label placement (PFLP) is the problem of placing text labels adjacent to point features on a map or diagram so as to maximize legibility. This problem occurs frequently in the production of many types of informational graphics, though it arises most often in automated cartography. In this paper we present a comprehensive treatment of the PFLP problem, viewed as a type of combinatorial optimization problem. Complexity analysis reveals that the basic PFLP problem and most interesting variants of it are NP-hard. These negative results help inform a survey of previously reported algorithms for PFLP; not surprisingly, all such algorithms either have exponential time complexity or are incomplete. To solve the PFLP problem in practice, then, we must rely on good heuristic methods. We propose two new methods, one based on a discrete form of gradient descent, the other on simulated annealing, and report on a series of empirical tests comparing these and the other known algorithms for the problem. Based on this study, the first to be conducted, we identify the best approaches as a function of available computation time.
Efficient Storage and Retrieval by Content and Address of Static Files
Authors: Elias Peter
Published: July 2002

We consider a set of static files or inventories, each consisting of the same number of entries, each entry a binary word of the same fixed length selected (with replacement) from the set of all binary sequences of that length, and the entries in each file sorted into lexical order. We also consider several retrieval questions of interest for each such file. One is to find the value of the
j
th entry, another to find the number of entries of value less than
k
.

When a binary representation of such a file is stored in computer memory and an algorithm or machine which knows only the file parameters (i.e. number of entries, number of possible values per entry) accesses some of the stored bits to answer a retrieval question, the
number of bits stored
and the
number of bits accessed per retrieval question
are two cost measures for the storage and retrieval task which have been used by Minsky and Papert. Bits stored depends on the representation chosen: bits accessed also depends on the retrieval question asked and on the algorithm used.

We give firm lower bounds to minimax measures of bits stored and bits accessed for each of four retrieval questions, and construct representations and algorithms for a bit-addressable machine which come within factors of two or three of attaining all four bounds at once for files of any size. All four factors approach one for large enough files.
The case against user interface consistency
Authors: Grudin Jonathan
Published: July 2002

Designers striving for user interface consistency can resemble Supreme Court justices trying to define pornography: each of us feels we know it when we see it, but people often disagree and a precise definition remains elusive. A close examination suggests that consistency is an unreliable guide and that designers would often do better to focus on users' work environments.
Lymphocyte Survival—The Struggle Against Death
Authors: Arch Robert H. , Thompson Craig B.
Published: July 2002

▪ Abstract  Cell proliferation and cell death must be closely regulated to maintain the integrity of the immune system during the lifetime of multicellular organisms. Proliferative expansion of lymphoid cells is required for effective immune responses against invading microorganisms. However, following infection eradication, expanded effector cells must be eliminated to prevent non-adaptive accumulation of cells. Therefore, higher vertebrates have developed an extensive network of signal transduction pathways that allow integration of cell survival and cell death stimuli. This network functions to ensure the controlled activation and expansion of cells during an immune response and the deletion of lymphoid cells that are no longer needed at the end of an immune response. Extracellular signals appear to control both mechanisms. Ultimate responses are integrated through cell surface receptors that are linked to intracellular signaling cascades. These signal transduction pathways converge to regulate cell fate at both transcriptional and post-transcriptional levels. In this review, the role of pathways triggered by TNFR-related molecules that determine the fate of lymphoid cells during development and activation is summarized.
Chemical and Biological Strategies for Engineering Cell Surface Glycosylation
Authors: Saxon Eliana , Bertozzi Carolyn R.
Published: July 2002

▪ Abstract  Oligosaccharides play a crucial role in many of the recognition, signaling, and adhesion events that take place at the surface of cells. Abnormalities in the synthesis or presentation of these carbohydrates can lead to misfolded and inactive proteins, as well as to several debilitating disease states. However, their diverse structures, which are the key to their function, have hampered studies by biologists and chemists alike. This review presents an overview of techniques for examining and manipulating cell surface oligosaccharides through genetic, enzymatic, and chemical strategies.