bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends and affordability of cigarette prices: ample room for tax increases and related health gains
Authors: Guindon G E , Tobin S , Yach D
Published: July 2002

Background: Increasing the price of tobacco products is arguably the most effective method of curbing the prevalence and consumption of tobacco products. Price increases would reduce the global burden of disease brought about by tobacco consumption.

Objectives: To compare cigarette price data from more than 80 countries using varying methods, examine trends in prices and affordability during the 1990s, and explore various policy implications pertaining to tobacco prices.

Design: March 2001 cigarette price data from the Economist Intelligence Unit are used to compare cigarette prices across countries. To facilitate comparison and to assess affordability, prices are presented in US dollars, purchasing power parity (PPP) units using the Big Mac index as an indicator of PPP and in terms of minutes of labour required to purchase a pack of cigarettes. Annual real percentage changes in cigarette prices between 1990 and 2000 and annual changes in the minutes of labour required to buy cigarettes between 1991 and 2000 are also calculated to examine trends.

Results: Cigarette prices tend to be higher in wealthier countries and in countries that have strong tobacco control programmes. On the other hand, minutes of labour required to purchase cigarettes vary vastly between countries. Trends between 1990 and 2000 in real prices and minutes of labour indicate, with some exceptions, that cigarettes have become more expensive in most developed countries but more affordable in many developing countries. However, in the UK, despite recent increases in price, cigarettes are still more affordable than they were in the 1960s.

Conclusions: The results suggest that there is ample room to increase tobacco prices through taxation. In too many countries, cigarette prices have failed to keep up with increases in the general price level of goods and services, rendering them more affordable in 2000 than they were at the beginning of the decade. Opportunities to increase government revenue and improve health through reduced consumption brought about by higher prices have been overlooked in many countries.
Late Pliocene fossils of Ecuador and their role in the development of the Panamic bioprovince after the rising of Central American Isthmus
Authors: Landini Walter , Bianucci Giovanni , Carnevale Giorgio , Ragaini Luca , Sorbini Chiara , Valleri Gigliola , Bisconti Michelangelo , Cantalamessa Gino , Celma Claudio Di
Published: July 2002

Studies carried on in the last several years allow us to date the Canoa Formation as Late Pliocene. The rich paleontological record (foraminifers, mollusks, and otoliths) allowed us to outline a first articulate picture of the biogeographic relationships in the tropical eastern Pacific during the Plio-Pleistocene. The mollusk fauna shows a Panamic connotation, as the majority (88.7%) of the extant species are present between the Gulf of California and the coasts of Ecuador or northern Peru. Benthic foraminifers assemblages indicate a temperate character with a certain affinity with the Mexican Pacific microfauna. More than 7000 otoliths have been found in the Canoa Formation that are attributed to 105 taxa of 46 fish families. Only 65% of the fossil association is living today along the Ecuadorian coasts, while the association as a whole shows closer relationships with the extant Californian fish community (about 80%). In particular, a conspicuous group of fishes (15 taxa) today spread in the boreal East Pacific (from Oregonian to Californian Province or limited only to the Californian area) has been recorded in the Canoa Formation. We named these taxa "Californian guests." After the rising of the Central American Isthmus, climatic variations may have caused changes in the pattern of surface currents and (or) activated coastal upwelling cells, supporting the diffusion of a part of the boreal biota toward more southern areas. At the present state of knowledge, both proximal causes seem to be compatible with the data presented.
Dynamic characteristics of the Confederation Bridge
Authors: Naumoski Nove , Cheung Moe S , Foo Simon
Published: July 2002

Dynamic characteristics of the Confederation Bridge were determined from recorded accelerograms of vibrations due to traffic and wind. Natural frequencies of four vertical and five transverse modes of the bridge were identified from the Fourier amplitude spectra of the accelerograms. By appropriate filtering and processing of the accelerograms, displacement time histories of vibrations associated with each of these modes were computed, which were used to determine the mode shapes of the bridge. These characteristics are essential for investigations of the dynamic performance of the bridge. The computed natural frequencies are significantly larger than those of the finite element model used in the design of the bridge. Since the dynamic effects due to traffic, wind, and seismic loads depend on the natural frequencies of the bridge, an evaluation study of these effects is needed using the natural frequencies and mode shapes obtained from measured vibrations.Key words: bridge, acceleration, displacement, record, vibration, filtering, frequency, mode, Fourier spectrum.
The hydrolysis of an activated ester by a tris(4,5-di-n-propyl-2-imidazolyl)phosphine-Zn2+ complex in neutral micellar medium as a model for carbonic anhydrase
Authors: Koerner Terry B , Brown R S
Published: July 2002

The properties of tris(4,5-di-n-propyl-2-imidazolyl)phosphineM2+ complexes (3M2+, M = Zn, Co) in neutral micellar media of Brij-35 and Triton X-100 have been studied in water with respect to their quantitative potenti metric titration, Co2+-visible absorption spectra, and ability of the 3Zn2+ complex to promote the hydrolysis of the activated ester, p-nitrophenyl acetate (PNPA). Potentiometric titration of the 3M2+(CIO4)2 complexes in 20 mM Brij-35 media yields a steep titration curve indicative of the cooperative consumption of two hydroxides, with computed pK1 and pK2 values of 8.75 and 6.25, respectively, and the midpoint of the titration curve (pKapp) being 7.50. A similar titration of the Co2+ complex also indicates cooperative consumption of two HO, and this is tied to the formation of a 4- or 5-coordinate complex, pKapp ~ 7.37.4. The cooperativity is explained in terms of sequential replacement of the two CIO4 ions associated with the 3M2+ to eventually yield 3M2+HO/(HO(H2O)n) having the first hydroxide ligated to the metal ion and the second associated as an ion pair. The 3Zn2+ complex catalyzes the hydrolysis of PNPA in 20 mM Brij-35 and 40 mM Triton X-100. Plots of the observed second order rate constant (k2) vs. pH in Brij-35 increase linearly with pH and plateau to a value of k2max = 0.86 M1 s1, with a kinetic pKa of 8.7. These data are analyzed by a process wherein the 3Zn2+HO is kinetically active in the rate-limiting step of the reaction, while the ion-paired (HO(H2O)n) exists as a spectator to the slow step, possibly promoting rapid breakdown of a tetrahedral intermediate. Analysis of the kinetic data in terms of a model that accounts for the partitioning of PNPA between water and hydrophobic micellar pseudophase indicates that the second-order rate constant of the micelle-bound ester is augmented by 45-fold due to loading of the PNPA substrate into the micelle. Key words: Brij-35, TritonX-100, neutral micelle, carbonic anhydrase model, kinetics, potentiometric titrations, catalysis, p-nitrophenyl acetate hydrolysis.
Estimation of wood stiffness of increment cores by near-infrared spectroscopy
Authors: Schimleck L R , Evans R , Ilic J , Matheson A C
Published: July 2002

The use of calibrated near-infrared (NIR) spectroscopy for predicting the radial variation of the longitudinal modulus of elasticity (EL) of increment cores is described. Sets of Eucalyptus delegatensis R.T. Baker (alpine ash) and Pinus radiata D. Don (radiata pine) samples were characterized in terms of EL(SS) (estimated stiffness based on a combination of SilviScan-2 diffractometric data and measured density (R. Evans and J. Ilic. 2001. For. Prod. J. 51(3): 5357)). NIR spectra, obtained from the radiallongitudinal face of each sample, were used to develop EL(SS) calibrations for the E. delegatensis and P. radiata sample sets and the two sets combined. The relationships between laboratory-determined EL(SS) and NIR-fitted EL(SS) were good in all cases. EL(SS) was estimated in separate test sets and found to correlate well with measured EL. NIR spectra were obtained in 15-mm sections from the radiallongitudinal face of two intact P. radiata increment cores. EL(SS) of each section was estimated using the P. radiata and the combined P. radiata and E. delegatensis calibrations. NIR estimates of EL(SS) were in good agreement with SilviScan-2 determined stiffness indicating that NIR spectroscopy can be successfully used to estimate radial variation in wood stiffness of increment cores.
Mortality in black spruce stands of fire or clear-cut origin
Authors: Lussier Jean-Martin , Morin Hubert , Gagnon Réjean
Published: July 2002

The mortality pattern of 14 black spruce (Picea mariana (Mill.) BSP) stands from the Saguenay region (Quebec), originating from fire or clear-cutting in the early 20th century, was reconstructed based on the dendrochronological dating of dead trees. Most of the spruces died during the 1970s and 1980s, which suggests the possible impact of the most recent spruce budworm (Choristoneura fumiferana Clem.) outbreak. This hypothesis is supported by the observation of major growth reductions synchronous with known outbreak periods and by the existence of a significant partial correlation between the mortality rates and the occurrence of outbreaks. A significant partial correlation between the mortality rates and the relative density of the studied stands suggests that competition amongst individuals might act as a predisposing factor to the death of trees, while the outbreaks act as an inciting factor. The observed mortality pattern is similar to self-thinning, since most of the dead trees were from the smallest size classes.
AN IMPROVED ALGORITHM FOR FINDING TREE DECOMPOSITIONS OF SMALL WIDTH
Authors: PERKOVIĆ LJUBOMIR , REED BRUCE
Published: July 2002

We present a modification of Bodlaender's linear time algorithm that, for constant k, determine whether an input graph G has treewidth k and, if so, constructs a tree decomposition of G of width at most k. Our algorithm has the following additional feature: if G has treewidth greater than k then a subgraph G′ of G of treewidth greater than k is returned along with a tree decomposition of G′ of width at most 2k. A consequence is that the fundamental disjoint rooted paths problem can now be solved in O(n2) time. This is the primary motivation of this paper.
EXISTENCE OF ALMOST EXPONENTIALLY DECAYING STATES FOR BARRIER POTENTIALS
Authors: LAVINE RICHARD
Published: July 2002

For a Schrödinger operator H on the half line whose potential has a trapping barrier, and is convex outside the barrier, there exists a φ, supported mostly inside the barrier, such that for t>0, <φ, e-iHtφ>~e-izt up to a small error, where φ is obtained by cutting off a nonnormalizable solution ψ of Hψ=zψ, and z is in the lower half-plane. The imaginary part of z is estimated explicitly, and the error estimate is explicitly proportional to | Im z log | Im z‖.
PROBABILITY MEASURES ON PROJECTIONS IN VON NEUMANN ALGEBRAS
Authors: MAEDA SHUICHIRO
Published: July 2002

A state ϕ on a von Neumann algebra A is a positive linear functional on A with ϕ(1) = 1, and the restriction of ϕ to the set of projections in A is a finitely additive probability measure. Recently it was proved that if A has no type I 2 summand then every finitely additive probability measure on projections can be extended to a state on A. Here we give precise and complete arguments for proving this result.
SUPERSELECTION STRUCTURE AND LOCALIZED CONNES’ COCYCLES
Authors: WIESBROCK HANS-WERNER
Published: July 2002

Let ρ be a localized endomorphism of the universal algebra of observables of a chiral conformal quantum field theory on a circle, see [16, 17, 23] or Chapter 1. Then ρ transforms covariant under the Möbius group. As was pointed out by D. Guido and R. Longo, [23], the covariance transformations are implemented by [Formula: see text] where Ad ∆it are modular groups to local algebras w.r.t. the vacuum vector, ut is a Connes-Radon-Nikodym-Cocycle. Using the localization property of ρ, one gets, at least for regular nets, localization properties of the cocycles. In this work we will do some steps into the opposite direction. Given a localized Connes’ cocycle of a local algebra. We will construct a localized endomorphism on the whole net. The features of this approach are twofold. Firstly sectors of finite and infinite statistical dimensions are handled on the same footing. Secondly it is a local theory right from the beginning. Moreover, soliton-like sectors can easily be incorporated. We will sketch on the last part. The program is carried through for a special class of conformal quantum field theories, the strongly additive ones.
THE STATISTICAL DIMENSION, CONJUGATION AND THE JONES INDEX
Authors: ROBERTS JOHN E.
Published: July 2002

A theory of dimension related to the Jones index and based on the notion of conjugation is developed for objects in a tensor C*-category. An elementary proof of the additivity and multiplicativity of the dimension is given and there is an associated trace.
VIRIAL RELATIONS FOR NONLINEAR WAVE EQUATIONS AND NONEXISTENCE OF ALMOST PERIODIC SOLUTIONS
Authors: PYKE RANDALL
Published: July 2002

We present a formalism for constructing integral identities involving time almost periodic solutions of nonlinear wave equations. As an application we prove a nonexistence theorem that is applicable to a large class of nonlinearities.
STABILITY OF CONIC BUNDLES: WITH AN APPENDIX BY MUNDET I RIERA
Authors: GÓMEZ TOMÁS L. , SOLS IGNACIO
Published: July 2002

Roughly speaking, a conic bundle is a surface, fibered over a curve, such that the fibers are conics (not necessarily smooth). We define stability for conic bundles and construct a moduli space. We prove that (after fixing some invariants) these moduli spaces are irreducible (under some conditions). Conic bundles can be thought of as generalizations of orthogonal bundles on curves. We show that in this particular case our definition of stability agrees with the definition of stability for orthogonal bundles. Finally, in an appendix by I. Mundet i Riera, a Hitchin-Kobayashi correspondence is stated for conic bundles.
Effects of Kampo Herbal Medicine on Plasma Melatonin Concentration in Patients
Authors: Watanabe Hareka , Kobayashi Takao , Tomii Meibou , Sekiguchi Yuki , Uchida Kazuhide , Aoki Tadashi , Cyong Jong-Chol
Published: July 2002

There are studies reporting that some natural products containing melatonin. Sleep disturbance and nocturnal polyuria are related to abnormal biorhythm. It is possible that Kampo medicine may influence biorhythm. We therefore examined the symptoms and plasma melatonin of patients treated with Rokumi-gan, Hachimi-jio-gan, Gosha-jinki-gan and Seishinrenshi-in. Furthermore, the concentration of four kampo medicines and crude drugs making up these formulations were investigated. Diurnal plasma melatonin was not affected by Rokumi-gan, but tended to be lowered by treatment with Hachimi-jio-gan, Gosha-jinki-gan and Seishinrenshi-in. Melatonin was present in several extracts from crude drugs, namely Rehmanniae radix, Moutan cortex, Cinnamomi cortex, Aconiti tuber, Plantaginis semen, Scutellariae radix and Lycii radicis cortex.
ON THE DETECTION OF SCALAR FIELD INDUCED SPACE–TIME TORSION
Authors: DERELI T. , TUCKER R. W.
Published: July 2002

We argue that the geodesic hypothesis based on autoparallels of the Levi–Cività connection may need refinement in the scalar–tensor theories of gravity. Based on a reformulation of the Brans–Dicke theory in terms of a connection with torsion determined dynamically in terms of the gradient of the Brans–Dicke scalar field, we compute the perihelion shift in the orbit of Mercury on the alternative hypothesis that its worldline is an autoparallel of a connection with torsion. If the Brans–Dicke scalar field couples significantly to matter and test particles move on such worldlines, the current time keeping methods based on the conventional geodesic hypothesis may need refinement.
THE ρ0-ρ± ELECTROMAGNETIC MASS SPLITTING
Authors: GAO DAO-NENG , YAN MU-LIN
Published: July 2002

A systematic method developed by us to evaluate the one-loop electromagnetic self-energies of the low-lying mesons is extended to the case of the ρ-meson. The theoretical prediction of ρ0-ρ± electromagnetic mass splitting is about 0.62 MeV, which is in agreement with the measurements.
ON THE UNIFICATION OF SCALES AND THE INFLATIONARY POTENTIAL
Authors: BANERJEE S. N. , CHAKRABARTI B. , BHATTACHARYA A.
Published: July 2002

We demonstrate that the four scales of energy in the evolution of the early universe can be unified through the scale symmetry. To do this, we adopt the viewpoint of an inflationary potential proposed earlier to encompass the Planck scale of energy. The consequences of the potential in the inflationary region are also discussed.
QUANTUM SPINOR FIELD IN THE FRW UNIVERSE WITH A CONSTANT ELECTROMAGNETIC BACKGROUND
Authors: GAVRILOV S. P. , GITMAN D. M. , GONÇALVES A. E.
Published: July 2002

This paper is a natural continuation of our paper Quantum Scalar Field in FRW Universe with Constant Electromagnetic Background, Int. J. Mod. Phys.A12, 4837 (1997). We generalize our previous work to the case of a massive spinor field, which is placed in a FRW universe of a special type with a constant electromagnetic field. So as to achieve this, special sets of exact solutions of the Dirac equation in the background under consideration are constructed and classified. Using these solutions representations for out–in, in–in, and out–out spinor Green functions are explicitly constructed as proper-time integrals over the corresponding contours in the complex proper-time plane. The vacuum-to-vacuum transition amplitude and the number of created particles are found and vacuum instability is discussed. The mean values of the current and of the energy–momentum tensor are evaluated, and different approximations for them are presented. The back reaction related to particle creation and to unstable vacuum polarization is estimated in different regimes.
Neutrino Zero Modes and Stability of Electroweak Strings
Authors: Stojkovic Dejan B.
Published: July 2002

We discuss massive and massless neutrino zero modes on electroweak strings. We argue that the eventual absence of the neutrino zero mode implies the existence of topogically stable strings where the required non-trivial topology has been induced by the fermionic sector.
NEW DIRECTIONS IN DATA ANALYSIS
Authors: BHAT PUSHPALATHA C.
Published: July 2002

In the next decade, high energy physicists will use very sophisticated equipment to record unprecedented amounts of data in the hope of making major advances in our understanding of particle phenomena. Some of the signals of new physics will be small, and the use of advanced analysis techniques will be crucial for optimizing signal to noise ratio. I will discuss new directions in data analysis and some novel methods that could prove to be particularly valuable for finding evidence of any new physics, for improving precision measurements and for exploring parameter spaces of theoretical models.
THE HAMILTON–JACOBI TREATMENT OF FRONT-FORM SCHWINGER MODEL
Authors: BALEANU DUMITRU , GÜLER YURDAHAN
Published: July 2002

The Hamilton–Jacobi formalism was applied to quantize the front-form Schwinger model. The importance of the surface term is discussed in detail. The BRST–anti-BRST symmetry was analyzed within Hamilton–Jacobi formalism.
A TWO-PARTICLE CLUSTER THEORY OF THE TRANSFORMED CHIRAL SYSTEM FOR LIQUID CRYSTALS
Authors: ZHIDONG ZHANG , JINWEI LIU , WU ZHANG
Published: July 2002

The chiral molecules are confined to the sites of a simple cubic lattice with their long axes in the XY-plane and the helix axis along the Z direction. The intermolecular interaction takes the form proposed by van der Meer et al. which is the simplest possible for chiral nematic liquid crystals. The chiral potential can thus be transformed to that for an achiral system but with different interactions between molecules in the same layer and those in neighboring layers. We have presented a generalized two-particle cluster theory which is suited for treating the model system with different neighboring intermolecular interactions. Such a theory has been used to study the transformed chiral system. The equation for the equilibrium distribution is solved by an iterative method. The temperature dependences of the order parameters T2and T4and of the internal energy per particle are calculated. The single orientational distribution function is shown at the scaled temperature t=2.3, i.e. near the phase transition in the simulation. The present theory, taking into account the short range correlations between molecules, yields improved results compared with the mean field theory.
ULTRAFAST OPTICAL RESPONSE IN GIANT MAGNETORESISTANCE MANGANITES
Authors: MERTELJ T. , BOSAK A. A. , GORBENKO O. YU. , KAUL A. R. , MIHAILOVIC D.
Published: July 2002

We measured optical time-resolved photoinduced reflectivity in La 0.82 Pb 0.18 MnO 3+δ thin film as a function of temperature. The photoinduced signal consists of initial fast relaxation on 200-300 fs scale followed by a slower relaxation on 10-100 ps timescale and extremely slow response on the ns-μs timescale. All components show distinctive changes below metal-insulator transition. Amplitudes of the faster components increase with decreasing temperature below metal-insulator transition indicating a bottleneck in the relaxation. The slow components amplitudes show distinctive peak at ~200 K indicating presence of localized states in the vicinity of the Fermi energy significantly below the metal-insulator transition.
INTERPLAY BETWEEN TRANSPORT, MAGNETIC-, AND STRUCTURAL PROPERTIES OF MN-PEROVSKITES WITH VARIOUS DOPING LEVEL
Authors: WAGNER P. , GORDON I. , DAS A. , VANACKEN J. , MOSHCHALKOV V. V. , BRUYNSERAEDE Y.
Published: July 2002

We performed a comparative study on the colossal negative magnetoresistivity and the Hall effect in thin films of the manganese perovskite La 1-x Ca x MnO 3 with x =0.3 and x =0.67. The underdoped sample ( x =0.3) undergoes a phase transition from a paramagnetic semiconductor to a ferromagnetic quasimetal at the Curie temperature T C =280 K , while the overdoped compound ( x =0.67) stays a paramagnetic semiconductor at all temperatures. Both materials show colossal negative magneto-resistivity, albeit on considerably different temperature- and field scales, depending on the magnetic interactions between neighbouring Mn ions. According to the Hall data, the charge carriers in the underdoped material are hole-type, partially compensated by an electron-type contribution. The overdoped system shows electronic carriers with a thermally activated concentration. The ordinary Hall effect is in both compounds superimposed by an anomalous Hall contribution with a sign opposite to the intrinsic charge-carrier type.
INTERACTIONS IN QUASICRYSTALS
Authors: VIDAL JULIEN , MOUHANNA DOMINIQUE , GIAMARCHI THIERRY
Published: July 2002

Although the effects of interactions in solid state systems still remains a widely open subject, some limiting cases such as the three dimensional Fermi liquid or the one-dimensional Luttinger liquid are by now well understood when one is dealing with interacting electrons in periodic crystalline structures. This problem is much more fascinating when periodicity is lacking as it is the case in quasicrystalline structures. Here, we discuss the influence of the interactions in quasicrystals and show, on a controlled one-dimensional model, that they lead to anomalous transport properties, intermediate between those of an interacting electron gas in a periodic and in a disordered potential.
DOPED MAGNETIC MOMENTS IN A DISORDERED ELECTRON SYSTEM: INSULATOR–METAL TRANSITION, SPIN GLASS AND "COLOSSAL MAGNETORESISTANCE"
Authors: KUMAR SANJEEV , MAJUMDAR PINAKI
Published: July 2002

Recent experiments on the amorphous magnetic semiconductor Gd x Si 1-x, have revealed an insulator–metal transition (IMT), as a function of doping and magnetic field, a spin glass state at low temperature, and colossal magnetoresistance close to the IMT. There are also signatures of strong electron–electron interaction close to the IMT. Motivated by these results we examine the role of doped magnetic moments in a strongly disordered electron system. In this paper we study a model of electrons coupled to structural disorder and (classical) magnetic moments, through an essentially exact combination of spin Monte Carlo and fermion exact diagonalisation. Our preliminary results, ignoring electron–electron interactions, highlights the interplay of structural and magnetic "disorder" which is primarily responsible for the observed features in magnetism and transport.
THE THERMAL TREATEMENT INFLUENCE ON THE ELECTRICAL RESISTANCE OF UNDERDOPED YBa2 (Cu0.96Fe0.04)3Oy SUPERCONDUCTOR
Authors: POP A. V. , ILONCA G. , POP V. , DELTOUR R.
Published: July 2002

The underdoped YBa 2 ( Cu 0.96 Fe 0.04)3 O y superconducting system has been prepared and investigated. The effect of oxygen content and the thermal treatment (fast quenching of underdoped samples from 250 K to 4.5 K) on the electrical resistance were studied. The semiconductor behaviour of electrical resistance after the fast quenching of the samples agree with a model for the stripe formation in Cu(2)O 2 plane. The presence of two resistive transitions (T c 1=18 K and T c2 =36 K ) were evidenced for y=6.75 sample. The disappearance of the low transition after the thermal treatment were analysed in relation with the role of Fe clusters on the order of apical oxygen. The decrease of T c by increasing oxygen deficiency was attributed to the fragmentation and stripe pinning in Cu(2)O 2 planes as a result of the disorder produced by the Fe clusters in Cu(1)O chains.
OPTICAL ABSORPTION OF CONFINED EXCITONS IN Tl HALIDE THIN FILMS
Authors: FUJII A. , ONO T. , YU W. , MAKI R.
Published: July 2002

Optical absorption spectra of the direct exciton of TlCl and TlBr micro-crystals are measured in evaporated thin films at 5.0K. The energy of the direct exciton bands shift to higher energy with decreasign micro-crystal size. The lower component of the doublet of the exciton in TlCl decreases its intensity with decreasing micro-crystal size. The experimental results are discussed with the quantum-size effect on the exciton states and on the electron-hole exchange interaction in an exciton.
PHONON SCATTERING OF FRENKEL EXCITONS IN MOLECULAR MICROCRYSTALLITES EMBEDDED IN A MATRIX
Authors: TAKESHIMA MASUMI , MIZUNO K. , MATSUI ATSUO H.
Published: July 2002

A matrix effect on the exciton-phonon coupling in microcrystallites embedded in a matrix is investigated theoretically. It is shown that a parameter σ defined as the square of the ratio of the phonon bandwidth of a matrix material to that of a microcrystallite material is a crucial one, affecting the exciton-phonon scattering. Phonons flow in the microcrystallite or out of it for either of σ > 1 or σ < 1, respectively; the probability for finding phonons in the microcrystallite increases with increasing σ. Thus the strength of the exciton-phonon coupling in the microcrystallite is influenced by phonons in the matrix. The flowing-in of phonons, which have energies higher than the maximum energy of phonons in the microcrystallite material, is of special importance and results in the broadening of the lines constituting an optical absorption spectrum.
DIFFUSION OF Tl+ IONS THROUGH THE INTERFACE OF SOLID NaCl, KCl OR RbCl AND LIQUID TlCl
Authors: YU W. , FUJII A.
Published: July 2002

The diffusion phenomena of thallous ions ( Tl + ions) through solid-liquid interface of liquid Tl + ions diffusion source and sodium chloride (NaCl) , potassium chloride (KCl) or rubidium chloride (RbCl) single crystals are studied by optical method. The characterisic absorption peaks of Tl + center in NaCl, KCl or RbCl single crystals were used as the tracer for measurements and the diffusion constants are evaluated at various temperatures. The results show that the diffusion constant of solid-liquid interface is about 103 times larger than that of solid-solid interface of KCl and TlCl .
GAP MEASUREMENTS IN MgB2 BREAK-JUNCTION AND POINT-CONTACT HETEROSTRUCTURES: TEST OF THE TWO-BAND MODELS
Authors: GONNELLI R. S. , UMMARINO G. A. , DAGHERO D. , CALZOLARI A. , STEPANOV V. A.
Published: July 2002

We present a series of results concerning the determination of the gap(s) in MgB2 by means of break-junction and point-contact measurements. We were able to observe the small 3D gap predicted by the two-band models for MgB2 in the clean limit as well as the gap in dirty limit. We were also able to follow the temperature evolution of the latter, from 4.2 K up to a reduced critical temperature. We show that all our results can be explained in the framework of the two-band model provided that the existence of a damaged surface in dirty limit proximized by the clean bulk as well as the occurrence of parallel contacts are admitted.
Rheological Changes of Suspensions Induced by Electrohydrodynamic Instability
Authors: Otsubo Yasufumi , Edamura Kazuya , Fukube Hiroyuki , Deyama Kazuhito
Published: July 2002

A new type of ER suspension is invented with a fluorinated organic compound. The suspensions show a viscosity increase without yield stress on the application of electric fields. The results cannot be explained by the chain formation mechanism. After the ER experiments, the plate surface of rheometer is covered with stripes of aggregated particles. The periodic structure may be formed in the electrified suspensions. When a dielectric liquid is subjected to high electric fields, the secondary motion of liquid can be induced. The electrohydrodynamic convection is responsible for the periodic distribution of particles. The ER effect of the suspensions may be generated by a combined effect of electrohydrodynamic convection and external shear.
CONDUCTANCE IN A NARROW CONSTRICTION THREADED BY AN IMPENETRABLE MAGNETIC FLUX TUBE
Authors: LIANG H. C.
Published: July 2002

The conductance G in a narrow constriction and its dependence on the Fermi energy and on the transverse position of an impenetrable magnetic flux tube is studied. G exhibits oscillatory-like behavior as the transverse position of the tube changes. When there are n propagating subbands, there are n-1 minimums of G first (except for n=1) and n minimums later when the Fermi energy grows. Both just below and just above the critical energy exhibiting n propagating subbands, minimums occur at tube positions mW/n, where W is the transverse width of the constriction and 1≤m≤n-1.
JOSEPHSON VORTEX FLOW IN Bi2Sr2CaCu2Oy INTRINSIC JOSEPHSON JUNCTIONS
Authors: IRIE AKINOBU , KANEKO SHOICHI , OYA GIN-ICHIRO
Published: July 2002

We have studied the vortex dynamics in intrinsic Josephson junctions in mesa-shaped Bi 2 Sr 2 CaCu 2 O y single crystals. By applying magnetic fields parallel to the copper oxide layers of the junctions, Josephson vortex-flow branches were observed in addition to multiple resistive branches on the I–V characteristics. From the field dependence of the maximum flow voltage, the flow velocity of the vortices was estimated to be ~3×106 m/s at 4.2 K, which is close to that of the highest-velocity mode of the electromagnetic wave in them. On the other hand, at 77 K, the velocity decreased from the highest to the lowest with an increase in the number of junctions in the mesas.
Numerical Studies of the Double Exchange Model
Authors: Wong C. K. , Lin H. Q.
Published: July 2002

We perform numerical simulations for the double exchange model. By minimizing the total energy, we obtain the ground state spin configuration and charge distribution as functions of electron density, the Hund's coupling JH, and the superexchange A. We present our studies for a wide range of parameters and also make comparison with the proposed canted and spiral phases.
THE INFLUENCE OF TEMPERATURE AND MAGNETIC FIELD ON THE TUNNELING TRANSPORT IN STM-TIP–NANOTUBE–SUBSTRATE SYSTEMS
Authors: ZHANG GANG , CAO ZHILIANG , GU BING-LIN
Published: July 2002

In this paper, we considered a single-wall carbon nanotube (SWNT) deposed on a substrate and probed by a scanning probe. We discuss the influence of magnetic field and temperature on the electronic properties of the SWNTs. From this paper we can see that both temperature and magnetic field are important for electron transport in such systems.
CONTROLLED NOT GATE BASED ON A TWO-LAYER SYSTEM OF THE FRACTIONAL QUANTUM HALL EFFECT
Authors: SUGAHARA MASANORI , KRUCHININ SERGEI
Published: July 2002

After a coordinate transformation, the wavefunction of the ground state of the fractional Quantum Hall Effect is found to be the congregation of free independent particles immune to thermal phonon disturbance. Based on the pseudo-spin states appearing in the two layer system of fractional Quantum Hall Effect, we propose a new controlled NOT gate with very large decoherence time.
INFLUENCE OF THE GROWTH AND POST DEPOSITION PROCESS ON THE PROPERTIES OF CdS THIN FILMS PREPARED BY CHEMICAL BATH DEPOSITION
Authors: REÁDIGOS A. ARIAS-CARBAJAL , VAILLANT L. , VIGIL-GALÁN O. , CONTRERAS-PUENTE G.
Published: July 2002

Studies of the properties of CBD-CdS thin films grown under variable conditions have been carried out. In particular,the influence of temperature, concentration of the reactants, application of a magnetic DC field and thermal annealing on the optical properties of the CDB-CdS has been studied. In this work, we are focusing our interest in the influence of the combination of the last two conditions, i.e., magnetic field application and annealing at 65, 75 and 85°C and a fixed c(thio)/c( Cd 2+) (ratio=1) on the band gap energy of CBD-CdS thin films for its use in solar cell as window material. The results about the influence of the substrate temperature and c(thio)/c( Cd 2+) ratios in the final thickness of the layers is also presented.
MAGNETIC AND ELECTRIC BEHAVIOR OF IRON IONS IN THE 3B2O3·CAO GLASS MATRIX
Authors: ARDELEAN I. , PĂŞCUŢĂ P. , IONCU V.
Published: July 2002

Magnetic susceptibility and electric resistivity measurements have been performed on x Fe 2 O 3 · (100-x)[3 B 2 O 3· CaO ] glasses with 0 5 mol% the iron ions participate in the negative superexchange interaction. From Curie constant values we have established that in these glasses both Fe 2+ and Fe 3+ ions are present, which explains their magnetic and electric behavior. The electrical resistivity and the conductivity activation energy decreases with the Fe 2 O 3 content. In order to analyze the electrical data, we have considered, in these glasses, a polaronic model for conduction.
STABILIZATION AGAINST RESISTANCE DEGRADATION OF SrTiO3 THIN FILMS BY Er DOPING
Authors: KITA R. , MATSU Y. , MASUDA Y. , YANO S.
Published: July 2002

Doping effect of Er on the resistance degradation of SrTiO 3 thin films was investigated. The rate of the resistance degradation was decreased with the increase of the Er content in the films. The increase in the leakage current density at 100°C for the Er-0.186-mol%-doped SrTiO 3 thin film was less than one order of magnitude even after 1000 h, while that for undoped SrTiO 3 thin films, it was by about one order of magnitude after 10 h. The Er-doped STO thin film also showed high stability of the interface between the films and the Pt electrodes against heat treatment in N 2.
CHAOTIC IMPULSE RADIO: A NOVEL CHAOTIC SECURE COMMUNICATION SYSTEM
Authors: YANG TAO , CHUA LEON O.
Published: July 2002

A chaotic impulse radio system is an ultrawide-band communication system that uses a train of very narrow baseband impulses as a carrier. In the transmitter of a chaotic impulse radio system, a message signal is modulated by two kinds of pulse carriers. Firstly, a frequency modulation is used to modulate the message signal into a subcarrier that functions as the clock pulses of a chaotic circuit. Driven by the modulated clock pulses, the chaotic circuit outputs a chaotic impulse positioning sequence which generates the positions of the carrier impulses. The specially designed chaotic circuit in the transmitter guarantees that the time intervals between the carrier impulses are chaotic. Thus the energy of the impulse carrier is distributed evenly over the entire bandwidth. In the receiver of a chaotic impulse radio system the message signal is demodulated in two stages. At the first stage, the time interval between two consecutive impulses is recovered. At the second stage, a simple algorithm based on the knowledge of the chaotic circuit in the transmitter is used to calculate partially the locations of the inner clock pulses which in turn are used to demodulate the message signal. No synchronization at any level is needed in this chaotic impulse radio system. The security of this chaotic impulse radio system depends on the hardware parameters of the chaotic circuit and the inner clock pulse train. Simulation results are presented to illustrate the design procedure of an example of this chaotic impulse radio system.
SYNCHRONIZATION IN GLOBALLY COUPLED MAPS
Authors: GELOVER-SANTIAGO A. L. , LIMA R. , MARTINEZ-MEKLER G.
Published: July 2002

In this work we study synchronization in a network of nonlinear elements with global couplings. We consider a family of maps and for each model we find sufficient conditions for synchronization. We also study cluster solutions and the corresponding low-dimensional maps.
INTERVAL METHODS FOR RIGOROUS INVESTIGATIONS OF PERIODIC ORBITS
Authors: GALIAS ZBIGNIEW
Published: July 2002

In this paper, we investigate the possibility of using interval arithmetic for rigorous investigations of periodic orbits in discrete-time dynamical systems with special emphasis on chaotic systems. We show that methods based on interval arithmetic when implemented properly are capable of finding all period-n cycles for considerable large n. We compare several interval methods for finding periodic orbits. We consider the interval Newton method and methods based on the Krawczyk operator and the Hansen–Sengupta operator. We also test the global versions of these three methods. We propose algorithms for computation of the invariant part and nonwandering part of a given set and for computation of the basin of attraction of stable periodic orbits, which allow reducing greatly the search space for periodic orbits.

As examples we consider two-dimensional chaotic discrete-time dynamical systems, defined by the Hénon map and the Ikeda map, with the "standard" parameter values for which the chaotic behavior is observed. For both maps using the algorithms presented in this paper, we find very good approximation of the invariant part and the nonwandering part of the region enclosing the chaotic attractor observed numerically. For the Hénon map we find all cycles with period n ≤ 30 belonging to the trapping region. For the Ikeda map we find the basin of attraction of the stable fixed point and all periodic orbits with period n ≤ 15. For both systems using the number of short cycles, we estimate its topological entropy.
STATISTICAL APPROACH TO MODELING OF SPATIOTEMPORAL DYNAMICS
Authors: MANDELJ SIMON , GRABEC IGOR , GOVEKAR EDVARD
Published: July 2002

Often in the analysis of spatially extended dynamic systems, we do not know an analytical model of the system dynamics, but we can provide spatiotemporal records of the characteristic state variable. The question then arises of how to extract a model of the system dynamics from the corresponding data. As a quite general solution of this problem, we propose a nonparametric statistical method of local modeling. The performance of the proposed method is demonstrated by predicting typical examples of spatiotemporal chaotic data. The results of modeling indicate that the statistical method can be applied to modeling the deterministic properties of spatiotemporal dynamics in terms of recorded data.
NOISE-ENHANCED WAVE TRAIN PROPAGATION IN UNEXCITABLE MEDIA
Authors: SENDIÑA-NADAL I. , PÉREZ-MUÑUZURI V.
Published: July 2002

The influence of spatiotemporal colored noise on wave train propagation in nonexcitable media is investigated. This study has been performed within the framework of the Oregonator model in terms of the characteristic noise parameters. Some features seen in single front propagation, like noise induced propagation facilitation for an optimal level of the noise intensity, are also found for periodic wave trains. The main new effect is, however, an enhancement of propagation for correlation times of the noise of the order of the period of the wave train.
ASYMPTOTIC ANALYSIS OF A NEW PIECEWISE-LINEAR CHAOTIC SYSTEM
Authors: AZIZ-ALAOUI M. A. , CHEN GUANRONG
Published: July 2002

Dynamical behavior of a new piecewise-linear continuous-time three-dimensional autonomous chaotic system is studied. System equilibria and their stabilities are discussed. Routes to chaos and bifurcations of the system are demonstrated with various numerical examples, where the chaotic features are justified numerically via computing the system fractal dimensions, Lyapunov exponents and power spectrum.
SYNCHRONIZATION IN SMALL-WORLD DYNAMICAL NETWORKS
Authors: WANG XIAO FAN , CHEN GUANRONG
Published: July 2002

We investigate synchronization in a network of continuous-time dynamical systems with small-world connections. The small-world network is obtained by randomly adding a small fraction of connection in an originally nearest-neighbor coupled network. We show that, for any given coupling strength and a sufficiently large number of cells, the small-world dynamical network will synchronize, even if the original nearest-neighbor coupled network cannot achieve synchronization under the same condition.
GENERALIZED INFORMATION CRITERION FOR LINEAR AND NONLINEAR PROCESSES
Authors: MATSUBA IKUO
Published: July 2002

A generalized information criterion is proposed to determine an embedding dimension and a delay time for delay coordinates of the reconstructed dynamics both for linear stochastic and nonlinear deterministic processes. While the standard maximum likelihood type method requires statistical parametric models such as autoregressive models, the generalized information criterion is constructed from the quantity in accordance with the second-order Renyi entropy in terms of the correlation integral for the finite number of data which is directly obtained from a time delay vector. It is found numerically that the present method works well when applied to chaotic and stochastic systems.
RESONANT LAYERS IN A PARAMETRICALLY EXCITED PENDULUM
Authors: LUO ALBERT C. J.
Published: July 2002

The energy increment spectrum method is developed for the numerical prediction of a specific primary resonant layer, and the width of the resonant layer can be estimated through the energy increment spectrum. This numerical approach is applied to investigate the (2M:1)-librational and (M:1)-rotational, resonant layers in a parametrically excited pendulum, and the corresponding analytical conditions for such resonant layers are developed. The numerical approach predicts the appearance and disappearance of resonant layers in nonlinear Hamiltonian systems rather than the conventional Poincaré mapping method. Illustrations of the analytical and numerical results for the appearance and disappearance of the resonant layers are given. The width of the resonant layers in the paremetric pendulum is computed. The analytical method should be further improved through renormalization.
SYNCHRONIZATION AND DECODING INTERSPIKE INTERVALS
Authors: HAN SEUNG KEE , KIM WON SUP , KOOK HYUNGTAE
Published: July 2002

Decoding of a sequence of interspike intervals (ISIs) of a neuron model driven by a chaotic stimulus is performed based on the attractor reconstruction method. As stimulus strength increases, both the stimulus estimation error and the prediction error in predicting stimulus crosswise by exploiting ISIs information tend to decrease with transitional drops at certain parameter values. It is analyzed that such behaviors are well explained in the context of synchronization between two chaotic patterns of stimulus and ISI sequence. The result implies that a new scheme of temporal coding at low firing rate regime can be achieved which exploits the preservation of nonlinear deterministic structures in stimulus.
IMPULSIVE CONTROL OF CHAOTIC SYSTEM
Authors: LIU XINZHI , TEO KOK LAY
Published: July 2002

This paper studies an impulsive control problem. By utilizing the method of Lyapunov functions, a set of impulsive stabilization criteria are established. These results are then applied to the Lorenz system. It is shown that by using impulsive feedback control, all the solutions of the Lorenz system will converge to an equilibrium point.
SELF-ORGANIZATION AND CHAOS IN ATMOSPHERE
Authors: RYMARZ C.
Published: July 2002

The paper contains considerations concerning two main phenomena in the dynamics of the atmosphere: self-organization and deterministic chaos. Coexisting, they can form the sequence modeling of living systems: Birth → Evolution → Death. Such kind of sequences are very universal in the atmosphere (atmospheric fronts, cyclones, etc.) Since deterministic chaos is investigated in literature intensively, in this paper the main attention is on the investigation of instabilities or phase transitions of the self-organization type. To this end the thermodynamics of the processes running far from equilibrium has been discussed. Two main instabilities of zonal, westerly flow have been investigated, applying the method of the Lapunov function. Following the procedure of nonequilibrium thermodynamics, sufficient conditions for the instabilities of zonal, westerly barotropic and baroclinic flows have been formulated. Applying the linear approximation to the boundary-value problem of the atmospheric flow in a layer heated below, the sequence of phenomena, from a heat conductivity, through the Benard convection, to a deterministic chaos, induced by the growing gradient of temperature, is presented.
DIFFUSIVE CUT-OFF SCALE OF FRACTAL SURFACES IN CHAOTIC MIXING
Authors: TOUSSAINT V. , CARRIÈRE PH.
Published: July 2002

Results concerning the fractal properties of isovalue surfaces of a passive, diffusive scalar field being advected by a three-dimensional, steady flow exhibiting chaotic streamlines are presented. For all the Péclet numbers and the flow fields studied, the mixing efficiency is shown to be related to the extent of the so-called advective zone for which the similarity dimension Ds is optimal in the sense of mixing (Ds=3). For global chaos, the effective mixing time can be related to the diffusive cut-off scale which bounds this zone. For partial chaos, this cut-off scale corresponds to the size of the regular region which limits asymptotically the mixing.
PROCESSES AND PRODUCTS IN A MULTI-LEVEL METAMODELING ARCHITECTURE
Authors: ATKINSON COLIN , KÜHNE THOMAS
Published: July 2002

Following the successful use of object-oriented metamodeling in the definition of the UML and other notation standards there is increasing interest in extending the approach to cover other concepts of software development, including processes. However, it turns out that the "obvious" approaches for using metamodels to describe processes and artifacts independently do not integrate well together in a natural and straightforward way. In this paper we discuss the problems and inconsistencies than can arise when trying to model a process and the products it creates within the same metamodeling framework, and present a solution that not only avoids many of these problems but also qualifies as a general metamodeling pattern. We then generalize the conceptual architecture to support the sound co-modeling of all independent areas of concern within the context of strict metamodeling.