bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of IL-6 protein expression in primary human renal cell carcinoma: an immunohistochemical study: Figure 1
Authors: Paule Bernard , Belot Jacqueline , Rudant Christiane , Coulombel Colette , Abbou Claude Clément
Published: July 2002

Aims—Interleukin 6 (IL-6) is produced by some renal carcinoma cell lines in vitro. This might be biologically important because IL-6 is a cytokine of particular interest, owing to its involvement in the growth of renal cell carcinoma. In this study, the expression of IL-6 protein in tissue samples from primary renal cell carcinoma was analysed, and then its clinical importance was examined.

Methods—The distribution of IL-6 in renal cell carcinoma was examined by means of an immunohistochemical method in 47 untreated primary renal cell carcinoma samples. The search for a significant difference between histological patterns, Furhman's grading system, TNM classification, and IL-6 protein expression was carried out.

Results—Immunohistochemistry demonstrated that IL-6 is expressed in 70% of primary tumours. There was no significant difference in the tumour size and grade between renal cell carcinomas with or without IL-6 expression. However, a relatively large number of high grade tumours expressed IL-6.

Conclusion—The importance of IL-6 expression with regard to tumour size/local growth is questionable because IL-6 has been correlated with the development of metastatic disease. These data suggest that the production of IL-6 could exert a growth inhibitory effect on primary renal cell carcinoma.
Immunohistochemical analysis of human CD5 positive B cells: mantle cells and mantle cell lymphoma are not equivalent in terms of CD5 expression
Authors: Su W , Yeong K F , Spencer J
Published: July 2002

CD5 is expressed by most T cells and a subset of B cells. Human CD5 positive B cells are present in fetal lymphoid tissue, their frequency decreasing with fetal age. In adult human tissues, CD5 positive B cells have been reported to be present in the germinal centre and mantle zone. Malignancies of CD5 positive B cells include mantle cell lymphoma and chronic lymphocytic leukemia. This report describes an immunohistochemical staining technique used to visualise the expression of CD5 by B cells in human fetal intestine, tonsil, and mantle cell lymphoma. B cells in fetal intestine, tonsillar epithelium, and mantle cell lymphoma all had a similar high intensity of CD5 expression. In contrast, CD5 B cells in the mantle and germinal centre expressed very small amounts of CD5, below the threshold of the technique. Therefore, mantle cells and mantle cell lymphoma are not equivalent in terms of CD5 expression.
Myelomatous involvement of the dura mater: a rare complication of multiple myeloma: Figure 1
Authors: Roddie P , Collie D , Johnson P
Published: July 2002

A case of myelomatous involvement of the dura mater is reported. The patient presented with blurring of vision in the right visual field and left sided facial numbness. A magnetic resonance imaging scan of the head revealed extensive infiltration of the dura mater. Cerebrospinal fluid (CSF) analysis showed no plasmacytosis and although there was a raised CSF protein concentration, no paraprotein band was detected, despite the presence of serum paraprotein. The infiltration of the dura mater is likely to have arisen by spread from contiguous bone lesions, contrasting with the pattern of spread seen in myelomatous involvement of the leptomeninges, which probably occurs through haematogenous seeding of the meninges. Leptomeningeal involvement is associated with a very poor prognosis; however, this patient had a favourable response to combined chemotherapy and cranial radiotherapy, suggesting that myelomatous involvement of the dura mater should be considered as a distinct complication of myeloma.
Development of a competency based training programme to support multidisciplinary working in a combined biochemistry/haematology laboratory
Authors: Woods R S , Longmire W , Galloway M J , Smellie W S A
Published: July 2002

The aim of this study was to develop a competency based training programme to support multidisciplinary working in a combined biochemistry and haematology laboratory. The training programme was developed to document that staff were trained in the full range of laboratory tests that they were expected to perform. This programme subsequently formed the basis for the annual performance review of all staff. All staff successfully completed the first phase of the programme. This allowed laboratory staff to work unsupervised at night as part of a partial shift system. All staff are now working towards achieving a level of competence equivalent to the training level required for state registration by the Council for Professions Supplementary to Medicine. External evaluation of the training programme has included accreditation by the Council for Professions Supplementary to Medicine and reinspection by Clinical Pathology Accreditation (UK) Ltd. The development of a competency based training system has facilitated the introduction of multidisciplinary working in the laboratory. In addition, it enables the documentation of all staff to ensure that they are fully trained and are keeping up to date, because the continuing professional development programme in use in our laboratory has been linked to this training scheme. This approach to documentation of training facilitated a recent reinspection by Clinical Pathology Accreditation (UK) Ltd.
Influence of solvent exposure and aging on cognitive functioning: an 18 year follow up of formerly exposed floor layers and their controls
Authors: Nilson L Nordling , Sällsten G , Hagberg S , Bäckman L , Barregård L
Published: July 2002

Objectives: To extend our knowledge of how exposure to neurotoxic substances during working life affects cognitive functioning in the long term. Does long term occupational exposure to organic solvents lead to aggravated cognitive impairment later in life?

Methods: A follow up was conducted of floor layers exposed to solvents and their unexposed referents (carpenters) 18 years after the baseline assessment. The pattern of cognitive changes in the two groups was compared, with the same 10 neuropsychological tests from the test battery for investigating functional disorders (TUFF) that were used at baseline. The study included 41 floor layers and 40 carpenters. A medical examination focused on health at the present and during the past 18 years. An extensive exposure assessment made in the initial study included questionnaires, interviews, and measurements. Additional exposure during the follow up period was minor, as explored in interviews at follow up.

Results: The entire group of floor layers did not deteriorate significantly more over time than did the carpenters. However, among the oldest subjects (>60 years), only floor layers showed decline in visual memory. Moreover, the most highly exposed floor layers deteriorated significantly more than their referents in visual memory and perceptual speed, and they tended to display larger decrements in motor speed. Significant dose effect relations were found; higher cumulative exposure was associated with decrements in visual episodic memory, perceptual speed and attention, and visuospatial skill.

Conclusions: The hypothesis that floor layers would deteriorate more in cognitive performance than their unexposed referents over a period of 18 years was partly supported by the results of this study. The results are consistent with the view that the negative effects of exposure to solvents may interact with the normal aging process, primarily at heavy exposure.
Mosaic haploiddiploid embryos and polyspermy in the tellinid bivalve Macoma balthica
Authors: Luttikhuizen Pieternella C , Pijnacker Laas P
Published: July 2002

We investigated meiosis, fertilization, and early development in eggs of the tellinid bivalve Macoma balthica (L.), which has external fertilization. Meiosis is standard but polyspermy is found to be very common. In all eight crosses examined, mosaic embryos consisting of a mixture of diploid (2n = 38) and haploid cells occur at a frequency ranging from 2.7 to 29.1%. The earliest mosaic found is in the two-cell stage. We propose that an androgenic haploid cell lineage can originate from one supernumerary sperm that decondenses into a functional haploid nucleus, starts mitosis, and is incorporated in the developing embryo.Key words: bivalves, fertilization, embryos, polyspermy, mosaicism.
SCHRÖDINGER OPERATORS ON HOMOGENEOUS METRIC TREES: SPECTRUM IN GAPS
Authors: SOBOLEV ALEXANDER V. , SOLOMYAK MICHAEL
Published: July 2002

The paper studies the spectral properties of the Schrödinger operator AgV = A0 + gV on a homogeneous rooted metric tree, with a decaying real-valued potential V and a coupling constant g ≥ 0. The spectrum of the free Laplacian A0 = -Δ has a band-gap structure with a single eigenvalue of infinite multiplicity in the middle of each finite gap. The perturbation gV gives rise to extra eigenvalues in the gaps. These eigenvalues are monotone functions of g if the potential V has a fixed sign. Assuming that the latter condition is satisfied and that V is symmetric, i.e. depends on the distance to the root of the tree, we carry out a detailed asymptotic analysis of the counting function of the discrete eigenvalues in the limit g → ∞. Depending on the sign and decay of V, this asymptotics is either of the Weyl type or is completely determined by the behaviour of V at infinity.
REGULARIZATION OF GENERAL MULTIDIMENSIONAL EPSTEIN ZETA-FUNCTIONS
Authors: ELIZALDE E. , ROMEO A.
Published: July 2002

We study expressions for the regularization of general multidimensional Epstein zeta-functions of the type [Formula: see text]

After reviewing some classical results in the light of the extended proof of zeta-function regularization recently obtained by the authors, approximate but very quickly convergent expressions for these functions are derived. This type of analysis has many interesting applications, e.g. in any quantum field theory defined in a partially compactified Euclidean spacetime or at finite temperature. As an example, we obtain the partition function for the Casimir effect at finite temperature.
GEOMETRY OF DEFORMED BOSON ALGEBRAS
Authors: CREHAN P. , HO T.G.
Published: July 2002

We consider a phase space realisation of an infinite parameter family of deformations of the boson algebra in which the q-deformed algebras arise as special cases. The deformation parameters are identified with coefficients of non-linear terms in the normal forms expansion of a family of classical Hamiltonian systems. These deformations simply correspond to nonlinear transformations of the boson algebra. They are physically interesting, as the deformed commutators consistently quantise a class of noncanonical classical Poisson structures.
Exponential Localization for Multi-Dimensional Schrödinger Operator with Random Point Potential
Authors: de Monvel Anne Boutet , Grinshpun Vadim
Published: July 2002

We consider a Schrödinger operator -Δα(ω) on L2(ℝd)(d=2,3) whose potential is a sum of point potentials, centered at sites of ℤd, with independent and identically distributed random amplitudes. We prove the existence of the pure point spectrum and the exponential decay of the corresponding eigenfunctions at the negative semi-axis for certain regimes of the disorder. In order to prove localization results, we elucidate the structure of the generalized eigenfunctions of -Δα(ω) and the relation between its negative spectrum and the spectra of a family of infinite-order operators on ℓ2(ℤd). We apply the multiscale analysis scheme to investigate the point spectrum of these operators. We also prove the absolute continuity of the integrated density of states of the operator on the negative part of its spectrum.
HOMOGENEITY OF THE PURE STATE SPACE FOR SEPARABLE C*-ALGEBRAS
Authors: FUTAMURA HAJIME , KATAOKA NOBUHIRO , KISHIMOTO AKITAKA
Published: July 2002

We prove that the pure state space is homogeneous under the action of the automorphism group (or a certain smaller group of approximately inner automorphisms) for a fairly large class of simple separable nuclear C*-algebras, including the approximately homogeneous C*-algebras and the class of purely infinite C*-algebras which has been recently classified by Kirchberg and Phillips. This extends the known results for UHF algebras and AF algebras by Powers and Bratteli.
q-DEFORMED W-ALGEBRA FROM q-FERMION OSCILLATORS AND THE ALGEBRAIC STRUCTURE OF VERTEX OPERATORS IN 2D STRING THEORY
Authors: PARTHASARATHY R.
Published: July 2002

q-deformed fermion oscillators are used to construct q-deformed higher order Virasaro algebra in the Fock space representation. These facilitate the realization of q-deformed W∞-algebra. The vertex operators (positively dressed) in 2D string theory are interpreted in terms of q-fermionic states.
RENORMALIZATION EFFECTS IN THE SUPERSTRING MODULI FROM THE HIGHER-DERIVATIVE TERMS
Authors: POLLOCK M. D.
Published: July 2002

The dimensional reduction of the effective ten-action [Formula: see text] of the heterotic superstring theory to the physical four-action S[gij] results in the appearance of three moduli B(a), whose real parts [Formula: see text], set equal for simplicity, define the radius and shape of the compact internal six-space [Formula: see text], in addition to the dilaton [Formula: see text], the ten-interval being [Formula: see text]. These scalar fields are massless at tree level and can be put into canonical form with coefficients [Formula: see text] for the positive kinetic-energy terms, when higher-derivative terms are ignored, as found by Witten, so that [Formula: see text]. Previously, we have shown that σA and σB acquire a potential from the higher-derivative terms [Formula: see text] and [Formula: see text], which becomes large close to the Planck era. Here, we discuss the renormalization of the kinetic-energy terms due to [Formula: see text] which, after diagonalization, results in a mixing of ∇σB with ∇σA, while the remaining coefficient of (∇σB)2 vanishes at t c ≈ t P /12 in a radiation-dominated Universe, corresponding to a temperature T c ≈ 5 × 1017 GeV , where the four-theory is still classical. At earlier times, the energy is unbounded from below, signalling that the four-theory has become unphysical, and that the string must still be in its uncompactified form with one dilaton ϕ, whose canonical kinetic energy is positive in the Einstein metric. This mechanism depends upon the equation of state of the source for the Friedmann expansion assumed, and is only effective for values of the adiabatic index in the range 1.14 < γ < 2.63, which thus includes radiation (γ = 4/3) and the Zel'dovich equation of state (γ = 2).
PRODUCTION AND TESTING OF THE DØ SILICON MICROSTRIP TRACKER
Authors:   For the DØ Collaboration., KESISIGLOU STILIANOS
Published: July 2002

We present the overview of the production and testing of the DØ Silicon Microstrip Tracker. Final assembly and anticipated performance of the deterctor are also discussed in this context.
MECHANISM OF STRIPES IN t–J MODEL
Authors: SAKAI TÔRU
Published: July 2002

We consider a possible mechanism of the charge stripe order due to the next-nearest neighbor exchange interaction J′ in the two-dimensional t–J model, based on the concept of the phase separation. We also calculate some hole correlation functions of the finite cluster of the model using the numerical diagonalization, to examine the realization of the mechanism.
INTERPLAY OF STRONG CORRELATION AND JAHN-TELLER EFFECT IN ORBITALLY DEGENERATE SYSTEMS
Authors: CAPONE M.
Published: July 2002

We study the unconventional insulating state in A 4 C 60 by means of the dynamical mean-field theory. The interplay between the electron-electron correlation and the Jahn-Teller interaction determines the properties of these compounds. The system is a Mott-Jahn-Teller insulator. In that state, conduction between molecules is blocked by on-site Coulomb repulsion, magnetism is suppressed by intra-molecular Jahn-Teller effect, and important excitations (such as optical and spin gap) are found to be essentially intra-molecular. Experimental values of the optical and spin gaps are recovered by our calculations.
HAMILTONIAN THEORY OF THE FRACTIONAL HALL EFFECT
Authors: SHANKAR R.
Published: July 2002

A brief introduction to the Hamiltonian approach to the Fractional Quantum Hall Effect (FQHE) is given. The theory is developed to a point where one can derive the trial wavefunctions of Laughlin and Jain. The reader is then guided to literature where further developments allowing detailed quantitative results are described.
THE HYDRODYNAMICAL LIMIT OF QUANTUM HALL SYSTEM
Authors: BABU D. SREEDHAR , SHANKAR R. , SIVAKUMAR M.
Published: July 2002

We study the current algebra of FQHE systems in the hydrodynamical limit of small amplitude, long-wavelength fluctuations. We show that the algebra simplifies considerably in this limit. The Hamiltonian is expressed in a current–current form and the operators creating inter-Landau level and lowest Landau level collective excitations are identified.
ENERGY-TRANSFER PROCESS IN RARE-EARTH-ION DOPED SrTiO3
Authors: OKAMOTO SHINJI , TANAKA SHOSAKU , YAMAMOTO HAJIME
Published: July 2002

Enhancement of emission intensity of rare-earth-ion doped SrTiO 3 by Al addition has been investigated. In the case of Pr 3+ and Tb 3+, addition of 23-mol% Al intensifies emission by more than 200 times. In contrast, the addition of 20 mol% Al intensifies emission at most by three times in the case of other rare-earth ions. The temperature dependence of PL spectra shows that the energy transfer from carriers to Pr 3+ or Tb 3+ ions is much more efficient than that to other rare-earth ions in SrTiO 3. It can be speculated that the energy transfer in SrTiO 3: Pr 3 or Tb 3+ occurs from carriers to Pr 3+ or Tb 3+ ion via 4f-5d transitions, which are much higher in oscillator strength than 4f-4f transitions.
CRYSTAL STRUCTURE AND PROPERTIES OF CU-AL-O THIN FILMS
Authors: WANG YUE , GONG HAO , LIU LING
Published: July 2002

P-type transparent conducting oxide thin films have attracted much attention due to their potential applications in novel transparent p-n junction devices. In this work, the transparent conducting Cu-Al-O thin films were prepared by the plasma enhanced chemical vapor deposition using metal organic precursors of Cu(acac) 2 and Al(acac) 3 (acac=acetylacetonate) while the substrate temperature was varied from 700 to 800°C. The x-ray diffraction and SEM results are analyzed to investigate the structure of the as-deposited and annealed films. The films contain metal copper and small grains of CuAlO 2. After annealing, metal copper turned into CuO . Hall effect measurements reveal that these films are p-type semiconductors and the film conductivity increased with the growth temperature.
EFFECT OF FOCUSSED VACUUM ARC PLASMA DEPOSITION ON THE PROPERTIES OF TETRAHEDRAL AMORPHOUS CARBON FILMS
Authors: CHUA DANIEL H. C. , TEO K. B. K. , TSAI T. H. , ROBERTSON J. , MILNE W. I.
Published: July 2002

We have investigated the effect of using a magnetic field to confine and focus the plasma in a Filtered Cathodic Vacuum Arc (FCVA) deposition system used for the preparation of tetrahedrally bonded amorphous carbon (ta-C) thin films. The design of the magnetic field is such that the plasma can be confined into a high-density focussed spot or de-focussed into a lower density wide beam. Increasing the magnetic field directly increases the plasma density and thus increases the deposition rate. The ta-C films grown in the magnetic field were subsequently characterised. EELS and Raman measurement were used to measure the sp3/sp2 ratio and UV-vis spectroscopy for optical bandgap studies. The intrinsic stress and I-V characteristics of the thin films were also studied. The results show that it is possible to deposit the films at rates as high as 2.5 nm/sec without adversely affecting the material properties.
TRAPPED BOSE GAS: MEAN-FIELD APPROXIMATION AND BEYOND
Authors: PITAEVSKII L. P.
Published: July 2002

The recent realization of Bose-Einstein condensation in atomic gases opens new possibilities for observation of macroscopic quantum phenomena. There are two important features of the system - weak interaction and significant spatial inhomogeneity. Because of this inhomogeneity a non-trivial "zeroth-order" theory exists, compared to the "first-order" Bogolubov theory. This theory is based on the mean-field Gross-Pitaevskii equation for the condensate ψ-function. The equation is classical in its essence but contains the ℏ constant explicitly. Phenomena such as collective modes, interference, tunneling, Josephson-like current and quantized vortex lines can be described using this equation. The study of deviations from the zeroth-order theory arising from zero-point and thermal fluctuations is also of great interest. Thermal fluctuations are described by elementary excitations which define the thermodynamic behaviour of the system and result in Landau-type damping of collective modes. Fluctuations of the phase of the condensate wave function restrict the monochromaticity of the Josephson current. Fluctuations of the numbers of quanta result in the quantum collapse-revival of the collective oscillations. This phenomenon is considered in some details. Collapse time for the JILA experimental conditions turns out to be of the order of seconds.
TOWARDS SINGLE-ELECTRON METROLOGY
Authors: FLENSBERG KARSTEN , ODINTSOV ARKADI A. , LIEFRINK FEIKE , TEUNISSEN PAUL
Published: July 2002

We review the status of the understanding of single-electron transport (SET) devices with respect to their applicability in metrology. Their envisioned role as the basis of a high-precision electrical standard is outlined and is discussed in the context of other standards. The operation principles of single electron transistors, turnstiles and pumps are explained and the fundamental limits of these devices are discussed in detail. We describe the various physical mechanisms that influence the device uncertainty and review the analytical and numerical methods needed to calculate the intrinsic uncertainty and to optimise the fabrication and operation parameters. Recent experimental results are evaluated and compared with theoretical predictions. Although there are discrepancies between theory and experiments, the intrinsic uncertainty is already small enough to start preparing for the first SET-based metrological applications.
SYMMETRIES RELATED TO YANG–BAXTER EQUATION AND REFLECTION EQUATIONS
Authors: KULISH P. P.
Published: July 2002

Some of main achievements obtained recently in investigations of the symmetry properties of systems solved by the quantum inverse scattering methods and connected with the Yang–Baxter equation and reflection equations are reviewed. Special attention is devoted to the twist procedure. Twist relates three constant R-matrices corresponding to Lie super-algebra gl(1|1).
PSEUDOGAP, CHARGE AND SPIN RESPONSES IN THE HUBBARD MODEL
Authors: MALOZOVSKY Y. M. , FAN J. D.
Published: July 2002

We have studied in terms of the effective T-matrix the self-energy part for both the attractive (U<0) and repulsive (U>0) Hubbard models. It is shown that the fluctuation pairing for strong coupling at T>T c for the attractive Hubbard model does not cause any pseudogap behavior in the single-particle density of states. We have also identified the origin of the false pseudogap for that case. Meanwhile, the fluctuation pairing significantly affect the density–density and the current–current correlation functions. As a result, there exists a pseudogap in the charge (and current) response for the attractive Hubbard model. In contrast, the pseudogap in the spin response appears to exist for the repulsive Hubbard model only. It is also shown that the contribution from the Hartree–"Cooper" channel gives an anomalous Fermi liquid term, Im χ c ≈-ω/T, to the charge response of the nearly antiferromagnetic Fermi liquid.
DEPOSITION OF SMALL Cu AND Au CLUSTERS ON Cu(001) SURFACE: STRUCTURE CHARACTERISTIC
Authors: XU Y. , PAN Z. Y. , WANG Y. X.
Published: July 2002

Deposition of small Cu and Au clusters on a Cu(001) surface was studied by molecular dynamics simulation using Finnis-Sinclair tight-binding potential. The impact energy varied from 0.1 to 6.0 eV/atom. The adlayer structure was found to be dependent on the specific substrate and projectile materials. The structure rearrangement of supported clusters on the surface was observed for both Cu and Au clusters. The Cu adlayer has a good fcc structure as that of substrate. However, the nanostructure was found for Au adlayer on a Cu(001) surface. Our results are consistent with other reports that the nanostructure is mainly caused by the lattice-parameter mismatch. Besides that, the cluster size and the impact energy are the key parameters that can affect the morphology of deposited films.
VISUAL INTERFACES TO COMPUTERS: A SYSTEMS-ORIENTED FIRST COURSE IN RELIABLE CONTROL VIA IMAGERY ("VISUAL INTERFACES")
Authors: KENDER JOHN R.
Published: July 2002

We present the rationale, description, and critique of a first course in image computing that is not a traditional computer vision principles-and-tools course. "Visual Interfaces to Computers" is instead complementary to standard Computer Vision, User Interface, and Graphics courses; in fact, VI:CV::UI:G. It is organized by case studies of working visual systems that use camera input for data or control information in service of higher user goals, such as GUI control, user identification, or automobile steering. Many CV scientific principles and engineering tools are therefore taught, as well as those of psychophysics, AI, and EE, but taught selectively and always within the context of total system design. Course content is derived from conference and journal articles and Ph.D. theses, augmented with video tapes and real-time web site demos. Students do two homework assignments, one to design a "visual combination lock", and one to parse an image into English. They also do a final paper or project of their own choosing, often in teams of two, and often with surprisingly deep results. The course is assisted by a custom C-based tool kit, "XILite", a user-friendly (and comparatively bug-free) modification of Sun's X-windows Image Library for our lab's camera-equipped Sun workstations. The course has been offered twice to a wide audience with good reviews.
FACE RECOGNITION USING SUPPORT VECTOR MACHINES WITH LOCAL CORRELATION KERNELS
Authors: KIM KWANG IN , KIM JIN HYUNG , JUNG KEECHUL
Published: July 2002

This paper presents a real-time face recognition system. For the system to be real time, no external time-consuming feature extraction method is used, rather the gray-level values of the raw pixels that make up the face pattern are fed directly to the recognizer. In order to absorb the resulting high dimensionality of the input space, support vector machines (SVMs), which are known to work well even in high-dimensional space, are used as the face recognizer. Furthermore, a modified form of polynomial kernel (local correlation kernel) is utilized to take account of prior knowledge about facial structures and is used as the alternative feature extractor. Since SVMs were originally developed for two-class classification, their basic scheme is extended for multiface recognition by adopting one-per-class decomposition. In order to make a final classification from several one-per-class SVM outputs, a neural network (NN) is used as the arbitrator. Experiments with ORL database show a recognition rate of 97.9% and speed of 0.22 seconds per face with 40 classes.
NONLINEAR DYNAMICS OF BANDPASS SIGMA-DELTA MODULATION — AN INVESTIGATION BY MEANS OF THE CRITICAL LINES TOOL
Authors: FEELY ORLA , FOURNIER-PRUNARET DANIELE , TARALOVA-ROUX INA , FITZGERALD DAVID
Published: July 2002

Bandpass sigma-delta modulation is a technique used to convert high-frequency narrowband electronic signals from analog form to digital, or vice versa. It is a fundamentally nonlinear technique, and therefore can be analyzed only approximately by application of linear analysis. The aim of this work is to present certain results concerning the dynamical behavior of bandpass sigma-delta modulators with zero input based on application of methods of nonlinear dynamics and noninvertible map theory. We will consider the effect of certain circuit imperfections on the behavior of the system, and will also consider the effect of operating in a chaotic regime. While many of our results arise from application of standard methods of nonlinear dynamics, we will emphasize in particular those results that can be obtained by application of the critical lines tool of Mira. The paper, therefore, has two aims: To investigate the nonlinear behavior of bandpass sigma-delta modulators and to provide a demonstration of the applicability of the critical lines tool to a system of engineering importance.
CHAOTIC BEHAVIOR OF THREE COMPETING SPECIES OF MAY–LEONARD MODEL UNDER SMALL PERIODIC PERTURBATIONS
Authors: AFRAIMOVICH VALENTIN S. , HSU SZE-BI , LIN HUEY-ER
Published: July 2002

The influence of periodic perturbations to a Lotka–Volterra system, modeling a competition between three species, is studied, provided that in the unperturbed case the system has a unique attractor — a contour of heteroclinic orbits joining unstable equilibria. It is shown that the perturbed system may manifest regular behavior corresponding to the existence of a smooth invariant torus, and, as well, may have chaotic regimes depending on some parameters. Theoretical results are confirmed by numerical simulations.
STRANGE NONCHAOTIC ATTRACTORS
Authors: PRASAD AWADHESH , NEGI SURENDRA SINGH , RAMASWAMY RAMAKRISHNA
Published: July 2002

Aperiodic dynamics which is nonchaotic is realized on Strange Nonchaotic Attractors (SNAs). Such attractors are generic in quasiperiodically driven nonlinear systems, and like strange attractors, are geometrically fractal. The largest Lyapunov exponent is zero or negative: trajectories do not show exponential sensitivity to initial conditions. In recent years, SNAs have been seen in a number of diverse experimental situations ranging from quasiperiodically driven mechanical or electronic systems to plasma discharges. An important connection is the equivalence between a quasiperiodically driven system and the Schrödinger equation for a particle in a related quasiperiodic potential, showing a correspondence between the localized states of the quantum problem with SNAs in the related dynamical system. In this review we discuss the main conceptual issues in the study of SNAs, including the different bifurcations or routes for the creation of such attractors, the methods of characterization, and the nature of dynamical transitions in quasiperiodically forced systems. The variation of the Lyapunov exponent, and the qualitative and quantitative aspects of its local fluctuation properties, have emerged as an important means of studying fractal attractors, and this analysis finds useful application here. The ubiquity of such attractors, in conjunction with their several unusual properties, suggests novel applications.
THE COMPOUND STRUCTURE OF CHEN'S ATTRACTOR
Authors: LÜ JINHU , ZHOU TIANSHOU , CHEN GUANRONG , ZHANG SUOCHUN
Published: July 2002

This Letter reports the finding of the compound structure of Chen's attractor, which is obtained by merging together two simple attractors after performing a mirror operation. Also, the forming procedure of Chen's attractor is explored.
AGENT UML: A FORMALISM FOR SPECIFYING MULTIAGENT SOFTWARE SYSTEMS
Authors: BAUER BERNHARD , MÜLLER JÖRG P. , ODELL JAMES
Published: July 2002

To gain wider acceptance for the use of agents in industry, it is a necessity to relate it to the nearest antecedent technology (object-oriented software development) and to introduce appropriate artifacts to support the development environment throughout the full system life cycle. We address both of these requirements by presenting AGENT UML, the Agent UML (Unified Modeling Language) — a set of UML idioms and extensions. This paper provides an AGENT UML representation of the internal behavior of an agent; it then relates this internal description to the external behavior of the agent by using and extending UML class diagrams and by describing agent interaction protocols in a new way. Our claim is that by extending the de-facto standard representation for object-oriented modeling to agents, the learning curve for object-oriented developers to adopt aspects of agent-based programming becomes much less steep. Thus, agent-oriented programming as a whole will become more amenable to mainstream software engineering.
A NEW PROOF OF SCHUTZENBERGER'S THEOREM
Authors: HIGGINS PETER M.
Published: July 2002

We prove the theorem of Schutzenberger that a language is star-free if and only if it is recognized by a finite monoid with trivial subgroups. The forward direction follows the lines of the proof of Kleene's Theorem which characterizes regular languages as those recognized by finite automata. The converse is a relatively short induction.
THE ASPHERICITY AND FREIHEITSSATZ FOR CERTAIN LOT-PRESENTATIONS OF GROUPS
Authors: IVANOV S. V. , KLYACHKO A. A.
Published: July 2002

Let U be a word in letters [Formula: see text], m >2, and a group G be given by presentation G=< x1,…, xm‖ U xi U-1= xi+1, i=1,…, m-1>. It is proven that this presentation is aspherical provided the word U does not have the form U2 U1, where U1 is a word in letters [Formula: see text] and U2 is a word in letters [Formula: see text]. It is also proven that the (images of) x1,…, xm-1 freely generate a free subgroup of G if and only if the word U does not have the foregoing form U2 U1.
CREATING KLEIN BOTTLES BY SURGERY ON KNOTS
Authors: TERAGAITO MASAKAZU
Published: July 2002

In the present paper, we will study the creation of Klein bottles by Dehn surgery on knots in the 3-sphere, and we will give an upper bound for slopes creating Klein bottles for non-cabled knots by using the genera of knots. In particular, it is shown that if a Klein bottle is created by Dehn surgery on a genus one knot then the knot is a doubled knot. As a corollary, we obtain that genus one, cross-cap number two knots are doubled knot.
A SPACETIME FOAM APPROACH TO THE COSMOLOGICAL CONSTANT AND ENTROPY
Authors: GARATTINI REMO
Published: July 2002

A simple model of spacetime foam, made by N wormholes in a semiclassical approximation, is taken under examination. The Casimir-like energy of the quantum fluctuation of such a model and its probability of being realized are computed. Implications on the Bekenstein–Hawking entropy and the cosmological constant are considered.
PROBABILITY FOR PRIMORDIAL BLACK HOLES IN HIGHER DERIVATIVE THEORIES
Authors: PAUL B. C. , SAHA ARINDAM
Published: July 2002

The probability for quantum creation of an inflationary universe with a pair of black holes in higher derivative theories has been studied. Considering a gravitational action which includes quadratic (αR2) and/or cubic term (βR3) in scalar curvature in addition to a cosmological constant (Λ) in semiclassical approximation with Hartle–Hawking boundary condition, the probability has been evaluated. The action of the instanton responsible for creating such a universe, with spatial section with S1XS2 topology, is found to be less than that with a spatial S3 topology, unless α < - 1/8Λ in R2-theory. In the R3 theory, however, there exists a set of solutions without a cosmological constant when βR2 = 1 and [Formula: see text] which admit primordial black holes (PBH) pair in an inflationary universe scenario. We note further that when βR2 ≠ 1, one gets PBH pairs in the two cases: (i) with α and Λ both positive and (ii) with Λ positive and α negative satisfying a constraint 6|α|Λ < 1. However, the relative probability for creation of an inflationary universe with a pair of black holes in the R3-theory suppresses when [Formula: see text] or [Formula: see text]. However, if the above constraints are relaxed one derives interesting results leading to a universe with PBH in R3-theory without cosmological constant.
LARGE-SCALE CRYOGENIC GRAVITATIONAL WAVE TELESCOPE
Authors:   LCGT Collaboration, KURODA KAZUAKI , OHASHI MASATAKE , MIYOKI SHINJI , TATSUMI DAISUKE , SATO SHUICHI , ISHIZUKA HIDEKI , FUJIMOTO MASA-KATSU , KAWAMURA SEIJI , TAKAHASHI RYUTARO , YAMAZAKI TOSHITAKA , ARAI KOJI , FUKUSHIMA MITSUHIRO , WASEDA KOICHI , TELADA SOUICHI , UEDA AKITOSHI , Shintomi Takakazu , YAMAMOTO AKIRA , SUZUKI TOSHIKAZU , SAITO YOSHIO , HARUYAMA TOMIYOSHI , SATO NOBUAKI , TSUBONO KIMIO , KAWABE KEITA , ANDO MASAKI , UEDA KEN-ICHI , YONEDA HITOKI , MUSHA MITSURU , MIO NORIKATSU , MORIWAKI SHIGENORI , ARAYA AKITO , KANDA NOBUYUKI , TOBAR MIKE E.
Published: July 2002

We present here the Large-scale Cryogenic Gravitational wave Telescope (LCGT) project which is aimed to improve the sensitivity of the existing gravitational wave projects by ten times. LCGT is the project constructing the km-scale gravitational wave detector in Japan succeeding the TAMA project, which adopts cryogenic mirrors with a higher power laser. We are planing to build it in an underground site in Kamioka mine. If its target sensitivity is attained, we will be able to catch a few events per month.
SiC SURFACE RECONSTRUCTION: RELEVANCY OF ATOMIC STRUCTURE FOR GROWTH TECHNOLOGY
Authors: STARKE U. , BERNHARDT J. , SCHARDT J. , HEINZ K.
Published: July 2002

Growth of SiC wafer material, of heterostructures with alternating SiC crystal modifications (polytypes), and of oxide layers on SiC are of importance for potential electronic device applications. By investigation of hexagonal SiC surfaces the importance of atomic surface structure for control of the respective growth processes involved is elucidated. Different reconstruction phases prepared by ex situ hydrogen treatment or by Si deposition and annealing in vacuum were analyzed using scanning tunneling microscopy (STM), Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED) crystallography. The extremely efficient dangling bond saturation of the SiC(0001)-(3×3) phase allows step flow growth for monocrystalline homoepitaxial layers. A switch to cubic layer stacking can be induced on hexagonal SiC(0001) samples when a [Formula: see text] phase is prepared. This might serve as seed for polytype heterostructures. Finally, we succeeded in preparing an epitaxially well matching silicon oxide monolayer with [Formula: see text] periodicity on both SiC(0001) and SiC[Formula: see text]. This initial layer promises to facilitate low defect density oxide films for MOS devices.
PERCUTANEOUS AND LIMITED OPEN REDUCTION OF INTRA-ARTICULAR DISTAL RADIAL FRACTURES
Authors: Geissler William B. , Fernandes Diego
Published: July 2002

Fluoroscopy monitors intra-articular distal radial fracture reduction and stabilisation. The reduction is guided by traction, ligamentotaxis and manipulation, and when necessary, completed by minimally invasive percutaneous or limited open instrumentation. Kirschner wires effectively splint the reduction until fracture callus is visualised on X-ray. An occasional mini plate is required to buttress a displaced volar medial lunate facet (die punch) fragment into position.

First, major metaphyseal articular fragments are approximated to restore the articular surface. Smaller fragments follow their larger counterparts into position or may be ignored (the "Rule of the Majority" or "Vassal Rule"). The repaired metaphysis is then aligned with and stabilised to the diaphysis. Cancellous bone may be inserted through small targeted incisions when defects and areas of comminution are present.

The wrist is splinted in a functional (slightly extended) position for three to four weeks in uncomplicated cases. Digital elevation and rehabilitation are emphasised during the early stages of fracture healing. After callus appears on X-ray, progressive wrist rehabilitation is initiated and the patients are weaned from their splints. Minimally invasive surgical intervention, good pain control and early rehabilitation maximise functional recovery and minimise morbidity, medical costs and lost work time.
A FORMAL YET PRACTICAL APPROACH TO ELECTRONIC COMMERCE
Authors: KONOPNICKI DAVID , LEIBA LIOR , SHMUELI ODED , SAGIV YEHOSHUA
Published: July 2002

This work explores (semi-)automated EC on the WWW. The EContracts framework enables EC WWW sites and EC automated tools to present standardized information. This information (1) allows each party to decide whether it wishes to engage in an EC activity with the other party, (2) enables automated negotiation between the parties, and (3) enables the establishment of an electronic contract, i.e. a formal description of an agreed upon EC transaction. The EContracts framework defines the basic software components of an EC party and their interconnections. Based on the EContracts framework, various applications can be built. Examples are deal making applications, deal feasibility checkers, brokers etc. Furthermore, the definitions of the data structures and the algorithms enable a theoretical investigation of automated commerce.
A STOCHASTIC CASCADE MODEL FOR FX DYNAMICS
Authors: BREYMANN WOLFGANG , GHASHGHAIE SHOALEH , TALKNER PETER
Published: July 2002

A time series model for the FX dynamics is presented which takes into account structural peculiarities of the market, namely its heterogeneity and an information flow from long to short time horizons. The model emerges from an analogy between FX dynamics and hydrodynamic turbulence. The heterogeneity of the market is modeled in the form of a multiplicative cascade of time scales ranging from several minutes to a few months, analogous to the Kolmogorov cascade in turbulence.

The model reproduces well the important empirical characteristics of FX rates for major currencies, as the heavy-tailed distribution of returns, their change in shape with the increasing time interval, and the persistence of volatility.
APPLICATION OF RANDOM MATRIX THEORY TO STUDY CROSS-CORRELATIONS OF STOCK PRICES
Authors: ROSENOW BERND , PLEROU VASILIKI , GOPIKRISHNAN PARAMESWARAN , AMARAL LUÍS A. NUNES , STANLEY H. EUGENE
Published: July 2002

We address the question of how to precisely identify correlated behavior between different firms in the economy by applying methods of random matrix theory (RMT). Specifically, we use methods of random matrix theory to analyze the cross-correlation matrix [Formula: see text] of price changes of the largest 1000 US stocks for the 2-year period 1994–1995. We find that the statistics of most of the eigenvalues in the spectrum of [Formula: see text] agree with the predictions of random matrix theory, but there are deviations for a few of the largest eigenvalues. To prove that the rest of the eigenvalues are genuinely random, we test for universal properties such as eigenvalue spacings and eigenvalue correlations. We demonstrate that [Formula: see text] shares universal properties with the Gaussian orthogonal ensemble of random matrices. In addition, we quantify the number of significant participants, that is companies, of the eigenvectors using the inverse participation ratio, and find eigenvectors with large inverse participation ratios at both edges of the eigenvalue spectrum — a situation reminiscent of results in localization theory.
EFFICIENCY IN DYNAMIC ENTRY GAMES: THE CASE OF QUANTITY COMPETITION
Authors: LAHMANDI-AYED RIM
Published: July 2002

The approach introduced by Gromb, Ponssard and Sevy (GPS) for dynamic entry games provides satisfactory results in the case of price competition but leaves the issue pending for quantity competition. This paper proposes a market attribution rule that restores the desired properties: average cost pricing in the symmetric case and the selection of the most efficient firm when asymmetry is introduced.
GLOBAL PULLBACK ATTRACTORS OF ${\mathbb C}$-ANALYTIC NONAUTONOMOUS DYNAMICAL SYSTEMS
Authors: CHEBAN DAVID N.
Published: July 2002

This is a systematic study of global pullback attractors of [Formula: see text]-analytic cocycles. For the large class of [Formula: see text]-analytic cocycles we give the description of structure of their pullback attractors. In particular we prove that it is trivial, i.e. the fibers of these attractors contain only one point. Several applications of these results are given (ODEs, Caratheodory's equations with almost periodic coefficients, almost periodic ODEs with impulse).
Markov analysis of software specifications
Authors: Whittaker James A. , Poore J. H.
Published: July 2002

A procedure for modeling software usage with the finite state, discrete parameter Markov chain is described. It involves rigorous analysis of the specification before design and coding begin. Many benefits emerge from this process, including the ability to synthesize a macro level usage distribution from a micro level understanding of how the software will be used. This usage distribution becomes the basis for a statistical test of the software, which is fundamental to the Cleanroom development process. Some analytical results known for Markov chains that have meaningful implications and interpretations for the software development process are described.
Biconnectivity approximations and graph carvings
Authors: Khuller Samir , Vishkin Uzi
Published: July 2002

A spanning tree in a graph is the smallest connected spanning subgraph. Given a graph, how does one find the smallest (i.e., least number of edges) 2-connected spanning subgraph (connectivity refers to both edge and vertex connectivity, if not specified)? Unfortunately, the problem is known to be NP-hard.

We consider the problem of finding a better approximation to the smallest 2-connected subgraph, by an efficient algorithm. For 2-edge connectivity, our algorithm guarantees a solution that is no more than 3/2 times the optimal. For 2-vertex connectivity, our algorithm guarantees a solution that is no more than 5/3 times the optimal. The previous best approximation factor is 2 for each of these problems. The new algorithms (and their analyses) depend upon a structure called a
carving
of a graph, which is of independent interest. We show that approximating the optimal solution to within an additive constant is NP-hard as well.

We also consider the case where the graph has edge weights. For this case, we show that an approximation factor of 2 is possible in polynomial time for finding a
k
-edge connected spanning subgraph. This improves an approximation factor of 3 for
k
= 2, due to Frederickson and Ja´Ja´ [1981], and extends it for any
k
(with an increased running time though).
Pseudorandom vector generation by the inversive method
Authors: Niederreiter Harald
Published: July 2002

Pseudorandom vectors are of importance for parallelized simulation methods. In this article we carry out a detailed analysis of the inversive method for the generation of uniform pseudorandom vectors. This method can be viewed as an analog of the inversive congruential method for pseudorandom number generation. We study, in particular, the periodicity properties and the behavior under the serial test for sequences of pseudorandom vectors generated by the inversive method.