bluuebunny/crossref_metadata_2025 huggingface dataset:
Excess molar volumes and viscosities of binary mixtures of some polyethers with propylamine at 298.15 K
Authors: Pal Amalendu , Bhardwaj Rakesh Kumar
Published: July 2002

Excess molar volumes (VmE) and dynamic viscosities (η) have been measured as a function of composition for binary liquid mixtures of propylamine with 2,5-dioxahexane, 2,5,8-trioxanonane, 2,5,8,11-tetraoxadodecane, 3,6,9-trioxaundecane, and 5,8,11-trioxapentadecane at 298.15 K. The excess volumes are positive over the entire range of composition for the systems propylamine + 2,5-dioxahexane, and + 3,6,9-trioxaundecane, negative for the systems propylamine + 2,5,8,11-tetraoxadodecane, and + 5,8,11-trioxapentadecane, and change sign from positive to negative for the remaining system propylamine + 2,5,8-trioxanonane. From the experimental data, deviations in the viscosity (Δln η) and excess energies of activation for viscous flow (ΔG*E) have been derived. These values are positive for all mixtures with the exception of propylamine + 2,5-dioxahexane.Key words : excess volume, viscosity, binary mixtures.
Relationship between heartwood radius and early radial growth, tree age, and climate in Pinus canariensis
Authors: Climent J , Chambel M R , Pérez E , Gil L , Pardos J
Published: July 2002

Heartwood radius at breast height was studied in 31 sampling sites from natural stands of Canary Islands pine (Pinus canariensis Chr. Sm. ex DC) covering the natural range of the species. After withdrawal of defective and nonheartwood samples, 1640 sound radial cores ranging in age from 30 to 265 years were analysed. Linearized models for the prediction of heartwood radius at breast height were obtained using stepwise regression methods. The best fit was attained including age and early radial growth variables (radius of the 25 or to the 50 inner rings), while stem radius inside bark and whole radial growth rate did not improve the prediction. Sampling sites were classified into five climate types, established according to the main plant communities associated with Pinus canariensis. The use of separate models for each climate type led to a significant reduction of the residual variance compared with multiple climate models. This confirmed that climate is an essential factor in heartwood development in Pinus canariensis even when 5173% of heartwood radius variation is explained by age and early growth. For fixed values of age and early growth, models predicted wider heartwood in drier climate types than in wet and high-altitude (supra-nubius) climate types.
Geographical variation in random amplified polymorphic DNA and quantitative traits in Norway spruce
Authors: Collignon Anne-Marie , Sype Hervé Van de , Favre Jean-Michel
Published: July 2002

Quantitative traits and random amplified polymorphic DNA variations were investigated on the whole natural range of Norway spruce (Picea abies (L.) Karst.). Results showed that the species can be separated into two main groups (northern and central Europe) using both types of characters. Such spatial and geographical fragmentation of species natural range rarely occurs in conifers and is consistent with prolonged geographical isolation within two refugial zones located in distinct environmental conditions (Moscow area and east of central European mountains). Within each of these two infraspecific groups, we revealed an apparent uncoupling between quantitative traits (related to growth, phenology, and wood quality) and DNA. However, the combination of both molecular and quantitative traits information provided new insights about geographical patterns of variation: a dominant latitudinal gradient was found in the Baltico-Nordic domain contrasting markedly with the main eastwest migration expected from pollen data, while in central Europe, a noticeable longitudinal gradient was congruent with eastwest migration. The concordance and discrepancies between quantitative traits and DNA are discussed in terms of historical events in P. abies.
Does food availability affect energy expenditure rates of nesting seabirds? A supplemental-feeding experiment with Black-legged Kittiwakes (Rissa tridactyla)
Authors: Jodice Patrick GR , Roby Daniel D , Hatch Scott A , Gill Verena A , Lanctot Richard B , Visser G Henk
Published: July 2002

We used a supplemental-feeding experiment, the doubly labeled water technique, and a model-selection approach based upon the Akaike Information Criterion to examine effects of food availability on energy expenditure rates of Black-legged Kittiwakes (Rissa tridactyla) raising young. Energy expenditure rates of supplementally fed females (n = 14) and males (n = 16) were 34 and 20% lower than those of control females (n = 14) and males (n = 18), respectively. Energy expenditure rates of females were more responsive to fluctuations in food availability than those of males. Fed males likely expended more energy while off the nest than fed females, possibly because of nest defense. Energy expenditure rates of fed kittiwakes were similar to values reported for kittiwakes that were either not raising young or not foraging. Parent kittiwakes, therefore, adjusted parental effort in response to variation in breeding conditions due to changes in food availability. Adjustments in reproductive effort in response to variable foraging conditions may have significant effects on the survival and productivity of individuals, and thus provide substantial fitness benefits for long-lived seabirds such as Black-legged Kittiwakes.
RANDOMIZED MOBILE AGENT BASED ROUTING IN WIRELESS NETWORKS
Authors: BUI MARC , DAS SAJAL K. , DATTA AJOY K. , NGUYEN DAI THO
Published: July 2002

We propose a novel approach for shortest path routing in wireless mobile networks. The approach makes use of n mobile agents initially launched from n mobile nodes forming the network. The agents move randomly from node to node and update routing information as they go. The approach is presented in this paper with two protocols. Both of them exhibit good performance in terms of the network and computing resource consumptions. The first protocol relies on independent mobile agents and imposes a minimum bandwidth requirement on individual mobile agents. Each agent carries the link state of its creator and this information remains unchanged except when the mobile agent returns to the home node. The second protocol is a refinement of the first protocol, with some form of interaction between the mobile agents. Each agent maintains the routing table of its creator instead of link state. The randomly walking agents spread the update information and compute the shortest paths via exchanging network state information between the routing tables they carry and the routing tables at the nodes they traverse. The correctness of the protocols is proven. Our analysis shows that the agent cooperation improves the system performance when dealing with topology and link cost changes.
PLANE WAVES WITH TRANSVERSE STRUCTURE
Authors: HILLION PIERRE
Published: July 2002

We prove that some inhomogeneous scalar waves among which the focus wave modes are nondispersive plane waves with a nonuniform transverse structure.
CHIRAL DECOMPOSITION AS A SOURCE OF QUANTUM SYMMETRY IN THE ISING MODEL
Authors: SZLACHÁNYI K.
Published: July 2002

The superselection sectors of three closely related models are studied and compared. I. The full Ising model with observable algebra [Formula: see text], the universal algebra of local even CAR algebras on the circle. [Formula: see text] has four sectors with Z(2) × Z(2) symmetry. II. The chiral Ising model with observable algebra [Formula: see text] (c = L or R), which is the universal algebra of local even Majorana algebras, has three sectors with quantum symmetry Gc ≅ M1⊕M1⊕M2. The Mack-Schomerus endomorphism creating the non-Abelian sector of [Formula: see text], respectively of [Formula: see text] is shown to coincide with the restriction [Formula: see text], respectively [Formula: see text] of a Z (2) charge creating automorphism ρ of [Formula: see text]. III. As an intermediate step the superselection sectors of the algebra [Formula: see text] — which can be interpreted as the observable algebra of the conformal Ising model — are found to have ordinary group symmetry described by the dihedral group D4. The relation between the sectors of [Formula: see text] and [Formula: see text] is explained in terms of a strange 'symmetry breaking': symmetry enhancement in the Neveu-Schwarz sector and symmetry breaking in the Ramond. Covariant charged fields are constructed in all three cases and the truncation in Gc is shown to arise from the failure of the Cuntz algebra relations for the chiral charged fields.
INTEGRABLE HIERARCHIES AND DISPERSIONLESS LIMIT
Authors: TAKASAKI KANEHISA , TAKEBE TAKASHI
Published: July 2002

Analogues of the KP and the Toda lattice hierarchy called dispersionless KP and Toda hierarchy are studied. Dressing operations in the dispersionless hierarchies are introduced as a canonical transformation, quantization of which is dressing operators of the ordinary KP and Toda hierarchy. An alternative construction of general solutions of the ordinary KP and Toda hierarchy is given as twistor construction which is quantization of the similar construction of solutions of dispersionless hierarchies. These results as well as those obtained in previous papers are presented with proofs and necessary technical details.
Stability of Bifurcating Solutions for the Ginzburg–Landau Equations
Authors: Bolley Catherine , Helffer Bernard
Published: July 2002

This paper is concerned with superconducting solutions of the Ginzburg–Landau equations for a film. We study the structure and the stability of the bifurcating solutions starting from normal solutions as functions of the parameters (κ, d), where d is the thickness of the film and κ is the Ginzburg–Landau parameter characterizing the material. Although κ and d play independent roles in the determination of these properties, we will exhibit the dominant role taken up by the product κd in the existence and uniqueness of bifurcating solutions as much as in their stability. Using the semi-classical analysis developed in our previous papers for getting the existence of asymmetric solutions and asymptotics for the supercooling field, we prove in particular that the symmetric bifurcating solutions are stable for (κ, d) such that κd is small and [Formula: see text] (for any η>0) and unstable for (κ, d) such that κd is large. We also show the existence of an explicit critical value Σ0 such that, for κ≤Σ0-η and κd large, the asymmetric solutions are unstable, while, for κ≥Σ0+η and κd large, the asymmetric solutions are stable.

Finally, we also analyze the symmetric problem which leads to other stability results.
QUANTUM DIFFERENTIAL OPERATORS ON ${\mathbb K} [ x ]$
Authors: IYER UMA N. , MCCUNE TIMOTHY C.
Published: July 2002

Following the definition given in [6], we compute the ring of quantum differential operators on the polynomial ring in 1 variable. We further study this ring.
QUANTUM LATTICE-GAS MODEL FOR THE DIFFUSION EQUATION
Authors: YEPEZ JEFFREY
Published: July 2002

Presented is a factorized quantum lattice-gas algorithm to model the diffusion equation. It is a minimal model with two qubits per node of a one-dimensional lattice and it is suitable for implementation on a large array of small quantum computers interconnected by nearest-neighbor classical communication channels. The quantum lattice-gas system is described at the mesoscopic scale by a lattice-Boltzmann equation whose collision term is unconditionally stable and obeys the principle of detailed balance. An analytical treatment of the model is given to predict a macroscopic effective field theory. The numerical simulations are in excellent agreement with the analytical results. In particular, numerical simulations confirm the value of the analytically calculated diffusion constant. The algorithm is time-explicit with numerical convergence that is first-order accurate in time and second-order accurate in space.
ACCOUNTING FOR INTANGIBLES: THE GREAT DIVIDE BETWEEN OBSCURITY IN INNOVATION ACTIVITIES AND THE BALANCE SHEET
Authors: WYATT ANNE
Published: July 2002

This paper analyses descriptive data from a discretionary accounting setting and several generic properties of innovation activities to explain why intangible assets are grossly under-recognized in company balance sheets. Existing literature and publicly available data indicates the increasing significance of intangible investment in the growth and development of firms and the stock of knowledge. However, a systematic framework to reliably quantify the stock of intangible assets remains elusive. This paper contributes to the debate surrounding recognition of intangible assets by demonstrating how economic attributes of intangible assets arise from generic features of innovation activities, and identifying the nature of the mis-match between accounting principles and the economic attributes of intangible assets which serves to reduce the relevance of accounting information. It is argued that accounting has become inwardly focused on the internal consistency of accounting relative to an outdated set of principles. Before an accounting asset can be recognized financial reporting systems typically require a 'cost' verifiable from a past transaction which the firm can directly link to expected future revenues. This narrow accounting approach is inconsistent with the properties of intangible investments in the knowledge-based economy.
SUPERFIELD APPROACH TO A NOVEL SYMMETRY FOR NON-ABELIAN GAUGE THEORY
Authors: MALIK R. P.
Published: July 2002

In the framework of superfield formalism, we demonstrate the existence of a new local, covariant, continuous and nilpotent (dual-BRST) symmetry for the BRST invariant Lagrangian density of a self-interacting two (1+1)-dimensional (2D) non-Abelian gauge theory (having no interaction with matter fields). The local and nilpotent Noether conserved charges corresponding to the above continuous symmetries find their geometrical interpretation as the translation generators along the odd (Grassmannian) directions of the four (2+2)-dimensional compact supermanifold.
THE ISOSPIN DISTRIBUTION OF FRAGMENTS IN REACTIONS 96Ru + 96Ru, 96Ru + 96Zr, 96Zr + 96Ru, and 96Zr + 96Zr AT BEAM ENERGY 400 AMeV
Authors: LI QINGFENG , LI ZHUXIA
Published: July 2002

The isospin distribution of particles and fragments in collisions 96Ru + 96Ru, 96Ru + 96Zr, 96Zr + 96Ru and 96Zr + 96Zr at beam energy 400 AMeV is studied with isospin-dependent QMD model. We find that the rapidity distribution of differential neutron–proton counting in neutron rich nucleus–nucleus collisions at intermediate energies is sensitive to the isospin-dependent part of nuclear potential. The study of the N/Z ratio of nucleons, light charged particles (LCP) and intermediate mass fragments (IMF) shows that the isospin-dependent part of nuclear potential drives IMF to be more isospin symmetric and emitted nucleons to be more neutron rich. From the study of the time evolution of the isospin distribution in emitted nucleons, LCP and IMF we find that neutrons diffuse much faster than protons at the beginning and the final isospin distribution is a result of dynamical balance of symmetry potential and Coulomb force under the charge conservation.
BOGOLUBOV'S RECURSION AND INTEGRABILITY OF EFFECTIVE ACTIONS
Authors: GERASIMOV A. , MOROZOV A. , SELIVANOV K.
Published: July 2002

The Hopf algebra of Feynman diagrams, analyzed by A. Connes and D. Kreimer, is considered from the perspective of the theory of effective actions and generalized τ-functions, which describes the action of diffeomorphism and shift groups in the moduli space of coupling constants. These considerations provide additional evidence of the hidden group (integrable) structure behind the standard formalism of quantum field theory.
A NEW APPROACH TO THE PARAMETRIZATION OF THE CABIBBO–KOBAYASHI–MASKAWA MATRIX
Authors: GUPTA V.
Published: July 2002

The CKM-matrix V is written as a linear combination of the unit matrix I and a matrix U which causes intergenerational-mixing. It is shown that such a V results from a class of quark-mass matrices. The matrix U has to be Hermitian and unitary and therefore can depend at most on four real parameters. The available data on the CKM-matrix including CP-violation can be reproduced by [Formula: see text]. This is also true for the special case when U depends on only 2 real parameters. Also, for such a V the invariant phase Φ≡ϕ12+ϕ23-ϕ13, satisfies a criterion suggested for "maximal" CP-violation.
SYMMETRY PROPERTIES, WARD IDENTITIES AND RENORMALIZATION GROUP FOR FERMI AND BOSE SYSTEMS
Authors: CAPRARA S. , CASTRO C. DI
Published: July 2002

Within the framework of the perturbative renormalization-group approach, we discuss the case when perturbation theory is affected by infrared divergences well inside a stable phase of matter. Contrary to the case of critical phenomena, a cancellation of the singularities, rather than a resummation, has to take place, in order to obtain finite response functions, as implied by the stability conditions. We show how symmetries, and related Ward identities, can be implemented to relate the singular parts of the different running coupling constants, and reduce the number of independent parameters, thus allowing for a closure of the renormalization-group equations, and for the asymptotical solution of the problem. Applications to the cases of Fermi and Bose systems in low spatial dimensions are discussed.
ON THE SUPER FIELD REALIZATION OF SUPER-CASIMIR ${\mathcal W} {\mathcal A} _n$ ALGEBRAS
Authors: ÖZER H. T.
Published: July 2002

We give an explicit quantum super field construction of the [Formula: see text] super-Casimir [Formula: see text] algebras, which is obtained from supersymmetric Miura transformation for the Lie super-algebra [Formula: see text]. And also we give an extension of this algebras including a super-vertex operator which depends on simple root system of [Formula: see text].
CASIMIR PROBLEM IN SPHERICAL DIELECTRICS: A QUANTUM STATISTICAL MECHANICAL APPROACH
Authors: BREVIK I. , AARSETH J. B. , HØYE J. S.
Published: July 2002

The Casimir mutual free energy F for a system of two dielectric concentric nonmagnetic spherical bodies is calculated, at arbitrary temperatures. Whereas F has recently been evaluated for the special case of metals (refractive index n = ∞), here analogous results are presented for dielectrics, and shown graphically when n = 2.0. Our calculational method relies upon quantum statistical mechanics. The Debye expansions for the Riccati-Bessel functions when carried out to a high order are found to be very useful in practice (thereby overflow/underflow problems are easily avoided), and also to give accurate results even for the lowest values of l. Another virtue of the Debye expansions is that the limiting case of metals becomes quite amenable to an analytical treatment in spherical geometry. We first discuss the zero-frequency TE mode problem from a mathematical viewpoint and then, as physical input, invoke the actual dispersion relations. The result of our analysis, based upon adoption of the Drude dispersion relation as the most correct one at low frequencies, is that the zero-frequency TE mode does not contribute for a metal. Accordingly, F turns out in this case to be only one half of the conventional value.
BIREFRINGENT ELECTROWEAK DEFECTS
Authors: THATCHER M. J. , MORGAN M. J.
Published: July 2002

In this paper we examine the propagation of electromagnetic waves through electroweak textures and W-strings. The photon is associated with a negative mass squared term as a consequence of its coupling to the intermediate vector bosons from which the electroweak defect is constructed. The photon pseudo-mass depends on the polarization of the photon and results in electroweak defects exhibiting birefringent properties. We calculate the effective refractive index and birefringence length scale. The cosmological implications of birefringent electroweak defects are discussed.
INTEGRAL REPRESENTATION FOR THE GR AND PARTITION FUNCTION IN QUANTUM STATISTICAL MECHANICS OF EXCLUSION STATISTICS
Authors: IGUCHI KAZUMOTO , AOMOTO KAZUHIKO
Published: July 2002

We derive an exact integral representation for the gr and partition function for an ideal gas with exclusion statistics. Using this we show how the Wu's equation for the exclusion statistics appears in the problem. This can be an alternative proof for the Wu's equation. We also discuss that singularities are related to the existence of a phase transition of the system.
STRUCTURE AND OPTICAL PROPERTIES OF NANOCRYSTALLINE ERBIA DOPED ZIRCONIA THIN FILMS
Authors: HARTRIDGE A. , KRISHNA M. GHANASHYAM , BHATTACHARYA A. K.
Published: July 2002

Thin films of zirconia doped with erbia in the concentration range of 5 to 15% have been prepared on quartz substrates by an inorganic and aqueous sol–gel method. The films were crystalline, continuous and single phase as deposited, with a cubic fluorite structure and crystallite sizes of 8–10 nm as shown by X-ray diffraction. The films were annealed to 600 and 1050°C after deposition and found to be transparent in the region between 400 to 1100 nm, the crystalline structure becoming tetragonal at 1050°C with crystallite sizes of around 30–40 nm. The refractive index increased with increase in annealing temperature. There is a peak in the refractive index at a dopant concentration of 10% where it achieves a value of 1.88 at 700 nm. The optical absorption edge shows a similar peak at the same dopant concentration with a value of 5.65 eV.
EFFECT OF NON-MAGNETIC IMPURITIES (Zn, Li) ON THE STRIPED STATE OF A SPIN-FERMION MODEL FOR CUPRATES
Authors: Moreo A.
Published: July 2002

The presence of stripes and the effect of adding non-magnetic impurities (NMI), such as Zn or Li, to high-Tc cuprates is studied applying Monte Carlo techniques to a spin-fermion model. It is observed that adding Li is qualitatively similar to diping with equa percentages of Sr and Zn. The mobile holes (MH) are trapped by the NMI and the system remains insulating and commensurate with antiferromagnetic (AF) correlations. This behavior persists in the region % NMI >% MH . On the other hand, when % NMI <% MH magnetic and charge incommensurabilities are observed. The vertical or horizontal holerich stripes, present when % NMI =0 upon hole doping, are pinned by the impurities and tend to become diagonal, surrounding finite AF domains. The % MH -% NMI plane is investigated. Good agreement with experimental results is found in the small portion of this diagram where experimental data are available. Predictions about the expected behavior in the remaining regions are made.
HOW MONTE CARLO SIMULATIONS CAN CLARIFY COMPLEX PROBLEMS IN STATISTICAL PHYSICS
Authors: BINDER KURT
Published: July 2002

Statistical mechanics of condensed matter systems in physics (fluids and solids) derives macroscopic equilibrium properties of these systems as averages computed from a Hamiltonian that describes the atomistic interactions in the system. While analytic methods for most problems involve uncontrolled approximations, Monte Carlo simulations allow numerically exact treatments, apart from statistical errors and from the systematic problem that finite systems are treated rather than the thermodynamic limit. However, this problem can be overcome by finite size scaling methods, and thus Monte Carlo methods have become a very powerful tool to study even complex phase transitions. Examples given will include unmixing of polymer blends, two-dimensional melting, etc.
STRIPED QUANTUM HALL PHASES
Authors: VON OPPEN FELIX , HALPERIN BERTRAND I. , STERN ADY
Published: July 2002

Recent experiments seem to confirm predictions that interactions lead to charge-density wave ground states in higher Landau levels. These new "correlated" ground states of the quantum Hall system mainfest themselves for example in a strongly anisotropic resistivity tensor. We give a brief introduction and overview of this new and emerging field.
INTERBAND TWO-PHOTON TRANSITION IN MOTT INSULATOR AS A NEW MECHANISM FOR ULTRAFAST OPTICAL NONLINEARITY
Authors: Ashida M. , Ogasawara T. , Motoyama N. , Eisaki H. , Uchida S. , Taguchi Y. , Tokura Y. , Kuwata-Gonokami M. , Ghosh H. , Shukla A. , Mazumdar S.
Published: July 2002

The dimensionality dependence of optical nonlinearity in cuprates was investigated by sub-picosecond pump-probe transmission measurements in the near-infrared region. It was found that cuprates with one-dimensional Cu-O networks show nonlinearity one order of magnitude larger than that of conventional band semiconductors and picosecond relaxation of the excited state. In contrast, a two-dimensional cuprate shows one order of magnitude smaller nonlinearity and slower decay of the excited state, as well as picosecond relaxation. The possibility for application of the present material to all-optical switching devices is also discussed.
PHOTOINDUCED PHASE TRANSITION IN SINGLE CRYSTALS ON URETHANE-SUSTITUTED POLYDIACETYLENES
Authors: Tachibana Hiroaki , Hosaka Noriko , Osaki Masayuki , Tokura Yoshinori
Published: July 2002

Thermochromic behaviors were investigated by measurements of reflectance spectra for urethane-substituted polydiacetylene crystal having side groups of R=(CH)2)6OCONHC2H5 (PDA-6UEt). The PDA-6UEt crystal shows an irreversible thermochromic A-to-B (blue-to-red) phase transition: the absorption band at 1.88 eV due to the lowest exciton shifts to higher energy (2.15 eV) in the heating run, but the reflectance spectra remain in the B phase even when cooled down to room temperature. We have demonstrated that photoinduced phase transition (PIPT) is observed by utilizing the irreversible A-to-B phase transition. The conversion shows the presence of a threshold of the light intensity and depends on photon energy, suggesting that the PIPT is mediated by the photogenerated electron-hole pairs.
INFRARED AND HYDROGEN EFFUSION STUDIES OF AMORPHOUS SILICON CARBON (a-Si:C:H) FILMS PREPARED BY DC MAGNETRON SPUTTERING (DCMS)
Authors: SALEH ROSARI , MUNISA LUSITRA , BEYER WOLFHARD
Published: July 2002

Infrared and effusion of hydrogen, as well as of the inert gases, were studied for dc magnetron sputtered a-Si:C:H films. A structural transition from compact to void-rich material is observed and attributed to hydrogen-induced void formation. Inert gas atoms were incorporated into the material by ion implantation. It is shown that the inert gas effusion spectra give the information about sizes of microstructure.
DECOMPOSITION OF CH4 ON SA TYPE STEPPED Si(100) SURFACE
Authors: KATIRCIOĞLU ŞENAY
Published: July 2002

Density functional theory method is used to explore the mechanism of dissociative adsorption of methane ( CH 4) on S A type stepped Si(100) surface. Two reaction paths are described that produce CH 3 and hydrogen atom fragments adsorbed on the dimer bonds present on each terraces. It has been found that, in the initial stage of the carbonization of stepped Si(100) surface, the CH 3 and H fragments bound to the Si dimer atoms by following the first reaction path.
AB INITIO CALCULATIONS FOR THE SQUARE-LATTICE ANISOTROPIC HEISENBERG MODEL
Authors: BISHOP R. F. , FARNELL D. J. J.
Published: July 2002

Interest in lattice quantum spin systems as models of quantum magnets has increased with the discovery of new and interesting magnetic materials. Here we use a well-known technique of quantum many-body theory, namely the coupled-cluster method (CCM), to investigate the nearest-neighbour, spin-½, anisotropic Heisenberg model on the square lattice. Ground-state expectation values for quantities such as the ground-state energy and the sublattice magnetisation are determined to an accuracy comparable with that of the best of other available techniques including Monte Carlo methods. In order to demonstrate this point we present results for various values of the anisotropy parameter, including those for the isotropic Heisenberg model and the isotropic XY model. We show that it is now possible to determine the presence and position of the quantum phase transitions using ab initio CCM calculations, and furthermore that we can accurately predict the critical behaviour at these points.
Textured Non-Magnetic Ni-V 10 % Alloy Tape for Epitaxial Growth of High TC Superconductors
Authors: Ceresara S. , Boffa V. , Petrisor T. , Fabbri F. , Scardi P.
Published: July 2002

The problem of developing non magnetic cube textured metallic substrates other than pure Ni, to be used for epitaxial deposition of Y-123 superconducting film (with an intermediate oxide buffer layer) is being tackled since three years by several laboratories. As reported in this paper, we have developed a new substrate, based on Ni-V 10 wt % alloy, which exhibits a cube texture comparable to Ni, but has a Curie temperature < 4.2 K; in addition, it has a hardness which is more than twice higher and a comparable oxidation resistance.
PrBa2Cu3O7-y: SUPERCONDUCTING OR ANOMALOUSLY MAGNETIC?
Authors: NAROZHNYI V. N. , ECKERT D. , NENKOV K. A. , FUCHS G. , MÜLLER K.-H. , UVAROVA T. G.
Published: July 2002

In PrBa 2 Cu 3 O 7-y (Pr123) single crystals grown by the flux method the kink in the magnetic susceptibility χab(T), connected with antiferromagnetic ordering of Pr, disappears after field cooling (FC) in a field H‖ab-plane whereas the kink in χc(T) remains unchanged after FC in H‖c-axis. This seems to be connected with the coupling between the Pr and Cu(2) sublattices. The Curie constant C determined from the data reported for superconducting Pr123 crystals grown by the traveling-solvent floating zone (TSFZ), method (Zou et al, Phys. Rev. Lett., 80, 1074 (1998)) is about one half of that for our flux-grown non-superconducting crystals. Thus, we propose that concentration of Pr in TSFZ crystals seems to be about one half of the nominal concentration for Pr123. Therefore, we propose that superconductivity in TSFZ samples is connected most probably with the partial substitution of Pr by nonmagnetic Ba.
DENATURATION AND EXCITED STATES OF SHORT DNAs
Authors: NYEO SU-LONG , YANG I-CHING
Published: July 2002

The statistical mechanics of a finite number of hydrogen bonds in very short DNAs is studied in the Peyrard–Bishop model with an estimate on the significance of the excited states of DNA.
SOME BIFURCATION DIAGRAMS FOR LIMIT CYCLES OF QUADRATIC DIFFERENTIAL SYSTEMS
Authors: CHAN H. S. Y. , CHUNG K. W. , QI DONGWEN
Published: July 2002

Concrete numerical examples of quadratic differential systems having three limit cycles surrounding one singular point are shown. In case another finite singular point also exists, a (3, 1) distribution of limit cycles is also obtained. This is the highest number of limit cycles known to occur in a quadratic differential system so far. Representative bifurcation diagrams are drawn for realistic parameter values.
ON AUTOPARAMETRIC ROUTE LEADING TO CHAOS IN DYNAMICAL SYSTEMS
Authors: VLADIMIROV S. N. , NEGRUL V. V.
Published: July 2002

Features of transition from regular types of oscillations to chaos in dynamic systems with finite and infinite dimensionality of phase space have been discussed. It has been found that for some types of nonlinearity, transition to the chaotic motion in these systems occurs according to the identical autoparametric scenario. The sequence of bifurcation phenomena looks as follows: equilibrium state ⇒ limit cycle ⇒ semitorus ⇒ strange attractor. On the basis of the results of numerical simulation a conclusion was made about the typical nature of such a scenario. The results of numerical calculations are confirmed by results of physical experiments carried out on the base of radiophysical self-oscillatory systems.
BIFURCATION STRUCTURE OF VIBRATIONS IN AN AGRICULTURAL TRACTOR-VIBRATING SUBSOILER SYSTEM
Authors: SAKAI KENSHI , AIHARA KAZUYUKI
Published: July 2002

The agricultural tractor-vibrating subsoiler system behaves as an impact oscillator. The bifurcation structure of vibrations of the system are investigated by field experiments by varying the forcing frequency and observing the periodic, period-doubling and chaotic vibrations. The position-triggered Poincaré sections are obtained by generating signals for a sampling timing and the structure of a strange attractor is clearly demonstrated on the Poincaré sections. The period-doubling route to chaos is identified experimentally for the tested tractor-implement system.
INTERACTION-ORIENTED SOFTWARE DEVELOPMENT
Authors: HUHNS MICHAEL N.
Published: July 2002

This paper describes a new approach to the production of robust software. We first motivate the approach by explaining why the two major goals of software engineering — correct software and reusable software — are not being addressed by the current state of software practice. We then describe a methodology based on active, cooperative, and persistent software components, i.e., agents, and show how the methodology produces robust and reusable software. We derive requirements for the structure and behavior of the agents, and report on preliminary experiments on applications based on the methodology. We conclude with a roadmap for development of the methodology and ruminations about uses for the new computational paradigm.
THE WAGNER HIERARCHY
Authors: CARTON OLIVIER , PERRIN DOMINIQUE
Published: July 2002

This paper is the second part of a series of two in which we present a new version of K. Wagner's hierarchy of ω-rational sets. The first paper presents a new approach to the concepts of chains and superchains. This one presents the classification itself.
A VISUALIZATION AND DESIGN TOOL (AVID) FOR DATA MINING WITH THE SELF-ORGANIZING FEATURE MAP
Authors: GEORGE SUSAN E.
Published: July 2002

This paper presents a software tool called AVID (A VIsualization and Design) which is particularly useful for data mining with an artificial neural network known as the self-organising feature map (SOM). AVID supports network training in both the i) selection of network inputs and ii) visualisation of the trained SOM. Both these features are novel aids to SOM network training and are particularly important when consideration is given to using the SOM for data mining. Once trained the SOM produces a 2-dimensional topological ordering of the input training data and it is particularly useful for representing the relationships within multi-dimensional data. The main classes within the data can be identified from the output map. AVID is an important software tool which enables data mining with the SOM by the selection of network inputs and the subsequent visualisation of the classes within these input vectors.
ACCELERATING UNIVERSES WITH SCALING DARK MATTER
Authors: CHEVALLIER MICHEL , POLARSKI DAVID
Published: July 2002

Friedmann–Robertson–Walker universes with a presently large fraction of the energy density stored in an X-component with wX<-1/3, are considered. We find all the critical points of the system for constant equations of state in that range. We consider further several background quantities that can distinguish the models with different wXvalues. Using a simple toy model with a varying equation of state, we show that even a large variation of wXat small redshifts is very difficult to observe with dL(z) measurements up to z~1. Therefore, it will require accurate measurements in the range 1<z<2 and independent accurate knowledge of Ωm,0(and/or ΩX,0) in order to resolve a variable wXfrom a constant wX.
CONFORMAL COLLINEATIONS IN STRING COSMOLOGY
Authors: BAYSAL HÜSNÜ , CAMCI UĞUR , TARHAN İSMAİL , YILMAZ İHSAN , YAVUZ İLHAMİ
Published: July 2002

In this paper, we study the consequences of the existence of conformal collineations (CC) for string cloud in the context of general relativity. Especially, we interest in special conformal collineation (SCC), generated by a special affine conformal collineation (SACC) in the string cloud. Some results on the restrictions imposed by a conformal collineation symmetry in the string cloud are obtained.
BINARY BLACK HOLE MERGERS IN 3d NUMERICAL RELATIVITY
Authors: BRÜGMANN BERND
Published: July 2002

The standard approach to the numerical evolution of black hole data using the ADM formulation with maximal slicing and vanishing shift is extended to non-symmetric black hole data containing black holes with linear momentum and spin by using a time-independent conformal rescaling based on the puncture representation of the black holes. We give an example for a concrete three dimensional numerical implementation. The main result of the simulations is that this approach allows for the first time to evolve through a brief period of the merger phase of the black hole inspiral.
SECOND-ORDER EIKONAL MODEL ANALYSIS OF16O+16OELASTIC SCATTERING
Authors: KIM YONG JOO , CHA MOON HOE
Published: July 2002

We analyze the elastic scattering angular distributions of the16O +16O system at Elab=480 MeV and 704 MeV within the framework of the second-order eikonal model based on Coulomb trajectories of colliding nuclei. The diffractive oscillatory structure observed in the elastic angular distribution could be explained due to the interference between the near- and far-side scattering amplitudes. The presence of a nuclear rainbow in this system is evidenced through a classical deflection function. The effective optical potential is developed from the second-order non-eikonal phase shifts.
BARYON MAGNETIC MOMENTS AND SPIN DEPENDENT QUARK FORCES
Authors: STROBEL GEORGE L.
Published: July 2002

The J=3/2 Δ, J=1/2 nucleon mass difference shows that quark energies can be spin dependent. It is natural to expect that quark wave functions also depend on spin. In the octet, such spin dependent forces lead to different wave functions for quarks with spin parallel or antiparallel to the nucleon spin. A two component Dirac equation wave function is used for the quarks assuming small current quark masses for the u and d quarks. Then, the neutron/proton magnetic moment ratio, the nucleon axial charge, and the spin content of the nucleon can all be simultaneously fit assuming isospin invariance between the u and d quarks, but allowing for spin dependent forces. The breakdown of the Coleman–Glashow sum rule for octet magnetic moments follows naturally in this Dirac approach as the bound quark energy also effects the magnetic moment. Empirically the bound quark energy increases with the number of strange quarks in the system. Allowing the strange quark wave function similar spin dependence predicts the magnetic moments of the octet, in close agreement with experiment. Differences between the octet and decuplet magnetic moments are also explained immediately with spin dependent wave functions.
PREFERRED SEQUENCES OF GENETIC EVENTS IN CARCINOGENESIS: QUANTITATIVE ASPECTS OF THE PROBLEM
Authors: SZABO ANIKO , YAKOVLEV ANDREI
Published: July 2002

In this paper we discuss some natural limitations in quantitative inference about the frequency, correlation and ordering of genetic events occurring in the course of tumor development. We consider a simple, yet frequently used experimental design, under which independent tumors are examined once for the presence/absence of specific mutations of interest. The most typical factors that affect the inference on the chronological order of genetic events are: a possible dependence of mutation rates, the sampling bias that arises from the observation process and small sample sizes. Our results clearly indicate that just these three factors alone may dramatically distort the outcome of data analysis, thereby leading to estimates of limited utility as an underpinning for mechanistic models of carcinogenesis.
THREE-DIMENSIONAL INFINITE ELEMENTS BASED ON A TREFFTZ FORMULATION
Authors: HARARI ISAAC , BARAI PARAMA , BARBONE PAUL E. , SLAVUTIN MICHAEL
Published: July 2002

Three-dimensional infinite elements for exterior problems of time-harmonic acoustics are developed. The infinite elements mesh only the outer boundary of the finite element domain and need not match the finite elements on the interface. A four-noded infinite element, based on separation of variables in spherical coordinates, is presented. Singular behavior of associated Legendre functions at the poles is circumvented. Numerical results validate the good performance of this approach.
THE USE OF THE HERGLOTZ FUNCTION METHOD TO RECONSTRUCT OBSTACLES FROM REAL AND FROM SYNTHETIC SCATTERING DATA
Authors: MAPONI PIERLUIGI , ZIRILLI FRANCESCO
Published: July 2002

We consider the problem of the reconstruction of the shape of an obstacle from some knowledge of the scattered waves generated from the interaction of the obstacle with known incident waves. More precisely we study this inverse scattering problem considering acoustic waves or electromagnetic waves. In both cases the waves are assumed harmonic in time. The obstacle is assumed cylindrically symmetric and some special incident waves are considered. This allows us to formulate the two scattering problems, i.e. the acoustic scattering problem and the electromagnetic scattering problem, as a boundary value problem for the scalar Helmholtz equation in two independent variables. The numerical algorithms proposed are based on the Herglotz Function Method, which has been introduced by Colton and Monk.1 We report the results obtained with these algorithms in the reconstruction of simple obstacles with Lipschitz boundary using experimental electromagnetic scattering data, that is the Ipswich Data2,3 and in the reconstruction of "multiscale obstacles" using synthetic acoustic scattering data.
A SUMMARY OF SOFTWARE RELIABILITY DEMONSTRATION TESTING MODELS
Authors: SAWADA KIYOSHI , SANDOH HIROAKI
Published: July 2002

This paper summarizes models for software reliability demonstration testing (SRDT). The models are briefly classified into three types: (1) continuous models, (2) discrete models and (3) models considering damage sizes of software failures. Under the continuous models, the software product of interest is tested for time t and is accepted if the number of software failures in the test does not exceed a prespecified integer s. The values of design variables, t and s are determined based on (i) the concept of a statistical test (a statistical model) and (ii) the Kullback–Leibler information (a K–L model). The K–L model has less parameters to be prespecified than the statistical model. Under the discrete models for SRDT, the software of interest is tested with n input data sets and is accepted if the number of input data sets causing software failures in the test does not exceed a prespecified integer c. A statistical model as well as a K–L model is described for the discrete models. Neither continuous nor discrete models in the above take the damage size of software failures into consideration. The third type of models are continuous and discrete models which consider the cumulative damage size caused by software failures as well as the number of software failures in the test.
INVESTIGATION OF SURFACE MAGNETIC STRUCTURE IN STEELS OF A SYSTEM Fe–Mn–Al–C BY ATOMIC FORCE MICROSCOPY
Authors: KLIMCHITSKAYA G. L. , PRIOLI R. , ZANETTE S. I. , CARIDE A. O. , ACSELRAD O. , KALASHNIKOV I. S. , SILVA E. M. , SIMÃO R. A.
Published: July 2002

Magnetic force microscopy (MFM) is used to investigate the surface magnetic structure of steels Fe–28Mn–8.5Al–1C–1.4Si under the different regimes of isothermal aging. A theoretical model for the MFM imaging of such structures is developed. Calculation of van der Waals forces is performed in order to interpret the topography images. The lateral resolution in terms of the magnetic field dependence on the surface coordinates is investigated. Finally, conditions that should be fulfilled for a good imaging of the samples are formulated.
SURFACE REACTIONS OF FERRITIC STEEL PARTICLES ATOMIZED WITH WATER OR MIXTURES OF WATER-ADDITIVE
Authors: ESTRADA J. L. , GODINEZ J. , HERRERA H.
Published: July 2002

The production of metallic powders has been a very important industrial activity for many years. In this work, the water or a mixture water-additive atomization process has been used. During the production of steel particles by water atomization these particles are coated with a surface oxide layer. With particles under these conditions it is very difficult to obtain final products with high mechanical properties, so that it is desirable to diminish the surface oxide as much as possible. Experimental tests to know if the use of additives as corrosion inhibitors, used to avoid steel oxidation at room temperature, could modify the properties of particles during the manufacture of an AISI C1115 steel by water atomization were carried out. In order to improve the knowledge of the chemical surface reactions, characterization of the powder surfaces and interfaces of metal matrix/oxide layer by means of Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM), X-ray Diffraction and Auger Electron Spectroscopy (AES) was carried out.
VASCULAR PEDICLE LENGTH AUGMENTATION IN REVERSED FOREARM FLAP FOR DISTAL FINGER RECONSTRUCTION
Authors: So Timothy Y.C.
Published: July 2002

This case report describes the successful reconstruction of double finger avulsion in a young patient by innervated reversed forearm flap. The flap was designed and raised with special care to provide a very long vascular pedicle without kinking. Release of the first compartment of the extensor retinaculum facilitated passage of the large flap under the extensor pollicis brevis and abductor pollicis longus tendons. Such a manoeuvre also allowed dissection at the anatomical snuffbox to further augment the pedicle length. By such technical modification, the reversed forearm flap can reach distal finger defects much easier.
MTV vs. Channel V
Authors: Ellis Paul
Published: July 2002

The American music channel MTV was the first to broadcast music television in Asia when it entered the market via Star TV's satellite feed in 1991. However, when Rupert Murdoch's News Corporation acquired Star TV two years later, MTV left the scene over a disagreement regarding the amount of local programming and a new player emerged in the form of Star TV's own Channel V. In contrast to the global approach of MTV, Channel V placed more emphasis on local artists and VJs and for a while enjoyed a monopoly position in the market. Later, in 1995, MTV returned to Asia with a new strategy of adapting the content while projecting a common brand image. MTV has since enjoyed rapid growth in the region resulting in fierce competition between the two channels. In 1999 the rivalry manifested itself in an escalating war of words between Steve Smith of Channel V and Frank Brown of MTV with each alleging that the other was misrepresenting distribution figures. The case documents this feud and its effect on advertisers in the context of the emerging Asian market for televised music.