bluuebunny/crossref_metadata_2025 huggingface dataset:
Directional Harmonic Theory: A Computational Gestalt Model to Account for Illusory Contour and Vertex Formation
Authors: Lehar Steven
Published: April 2003

Visual illusions and perceptual grouping phenomena offer an invaluable tool for probing the computational mechanism of low-level visual processing. Some illusions, like the Kanizsa figure, reveal illusory contours that form edges collinear with the inducing stimulus. This kind of illusory contour has been modeled by neural network models by way of cells equipped with elongated spatial receptive fields designed to detect and complete the collinear alignment. There are, however, other illusory groupings which are not so easy to account for in neural network terms. The Ehrenstein illusion exhibits an illusory contour that forms a contour orthogonal to the stimulus instead of collinear with it. Other perceptual grouping effects reveal illusory contours that exhibit a sharp corner or vertex, and still others take the form of vertices defined by the intersection of three, four, or more illusory contours that meet at a point. A direct extension of the collinear completion models to account for these phenomena tends towards a combinatorial explosion, because it would suggest cells with specialized receptive fields configured to perform each of those completion types, each of which would have to be replicated at every location and every orientation across the visual field. These phenomena therefore challenge the adequacy of the neural network approach to account for these diverse perceptual phenomena.

I have proposed elsewhere an alternative paradigm of neurocomputation in the harmonic resonance theory (Lehar 1999, see website), whereby pattern recognition and completion are performed by spatial standing waves across the neural substrate. The standing waves perform a computational function analogous to that of the spatial receptive fields of the neural network approach, except that, unlike that paradigm, a single resonance mechanism performs a function equivalent to a whole array of spatial receptive fields of different spatial configurations and of different orientations, and thereby avoids the combinatorial explosion inherent in the older paradigm. The present paper presents the directional harmonic model, a more specific development of the harmonic resonance theory, designed to account for specific perceptual grouping phenomena. Computer simulations of the directional harmonic model show that it can account for collinear contours as observed in the Kanizsa figure, orthogonal contours as seen in the Ehrenstein illusion, and a number of illusory vertex percepts composed of two, three, or more illusory contours that meet in a variety of configurations.
Physical and psychosocial risk factors for lateral epicondylitis: a population based case-referent study
Authors: Haahr J P , Andersen J H
Published: April 2003

Aims:To assess the importance of physical and psychosocial risk factors for lateral epicondylitis (tennis elbow).

Methods:Case-referent study of 267 new cases of tennis elbow and 388 referents from the background population enrolled from general practices in Ringkjoebing County, Denmark.

Results:Manual job tasks were associated with tennis elbow (odds ratio (OR) 3.1, 95% confidence interval (CI) 1.9 to 5.1). The self reported physical risk factors “posture” and “forceful work” were related to tennis elbow. Among women, work involving performing repeated movements of the arms was related to tennis elbow (OR 3.7, CI 1.7 to 8.3). Among men, work with precision demanding movements was related to tennis elbow (OR 5.2, CI 1.5 to 17.9). Among both males and females, the results for work with hand held vibrating tools were inconsistent, partly because of few exposed subjects. A physical strain index was established based on posture, repetition, and force. The adjusted ORs for tennis elbow at low, medium, and high strain were 1.4 (CI 0.8 to 2.7), 2.0 (CI 1.1 to 3.7), and 4.4 (CI 2.3 to 8.7). Low social support at work, adjusted for physical strain, was a risk factor among women (OR 2.4, CI 1.3 to 4.6).

Conclusion:Results indicate that being a new case of tennis elbow is associated with non-neutral postures of hands and arms, use of heavy hand held tools, and high physical strain measured as a combination of forceful work, non-neutral posture of hands and arms, and repetition. Furthermore, tennis elbow among women was associated with low social support at work. The results for precision demanding movements and for vibration were less consistent.
Residential and occupational exposure to 50 Hz magnetic fields and malignant melanoma: a population based study
Authors: Tynes T , Klæboe L , Haldorsen T
Published: April 2003

Aims:To test the hypothesis that exposure to electromagnetic fields from high voltage power lines increases the incidence of cutaneous malignant melanoma in adults aged 16 and above.

Methods:Nested case-control study. The study population comprised subjects aged 16 and above who had lived in a residence situated in a broad corridor around a high voltage power line in 1980, or one of the years from 1986 to 1996. The cases were incident cases that were diagnosed in 1980–96 and reported to the Cancer Registry of Norway. Two controls were matched to each case by year of birth, sex, municipality, and first year entering the cohort. Time weighted average exposure to residential magnetic fields generated by the power lines was calculated for the exposure follow up from 1 January 1967 until diagnosis by means of a computer program, in which distance from residency to the line, line configuration, and current load were taken into account. Exposure was analysed using cut off points at 0.05 and 0.2 microtesla (μT). Exposure to magnetic fields at work was classified by an expert panel who assessed magnetic field exposure by combining branch and occupation into one of three levels: <4 hours, 4–24 hours, and >24 hours per week above background (0.1 μT). The categories were cumulated over the occupationally active years for the exposure follow up from 1 January 1955 until diagnosis, and cut off points at 18 and 31 category-years were evaluated.

Results:Analysis of the two upper residential magnetic field categories showed an odds ratio of 2.01 (95% CI 1.09 to 3.69) and 2.68 (95% CI 1.43 to 5.04) for women, and an odds ratio of 1.70 (95% CI 0.96 to 3.01) and 1.37 (95% CI 0.77 to 2.44) for men, respectively. Occupational exposure showed no significant association with cutaneous malignant melanoma, and analysis of both residential and occupational exposure simultaneously, showed no additional effect.

Conclusion:The present study provides some support for an association between exposure to calculated residential magnetic fields and cutaneous malignant melanoma, but because of the lack of a biological hypothesis and the known strong association between solar radiation and melanoma, no firm conclusions can be drawn and further studies would be of interest.
Return to work of cancer survivors: a prospective cohort study into the quality of rehabilitation by occupational physicians
Authors: Verbeek J , Spelten E , Kammeijer M , Sprangers M
Published: April 2003

Aims:To describe and assess the quality of rehabilitation of cancer survivors by occupational physicians and to relate the quality of the process of occupational rehabilitation to the outcome of return to work.

Methods:One hundred occupational physicians of a cohort of cancer survivors were interviewed about return to work management. Quality of rehabilitation was assessed by means of four indicators that related to performance in knowledge of cancer and treatment, continuity of care, patients complaints, and relations at work. The cohort of patients was prospectively followed for 12 months to assess time to return to work and rate of return to work. Patients’ and physicians’ satisfaction with care was also assessed. The relation between performance and these outcome measures was studied in a multivariate analysis, taking into account the influence of other work and disease related factors that could potentially predict return to work.

Results:For knowledge of cancer and treatment, only 3% had optimal performance because occupational physicians did not communicate with treating physicians. For continuity of care, patient complaints, and relations at work, performance was optimal for 55%, 78%, and 60% of the physicians respectively. After adjustment for other prognostic factors, overall physician’s performance (hazard ratio (HR) 0.5, 95% CI 0.3 to 0.8) and continuity of care (HR 0.5, 95% CI 0.3 to 0.9) were related to the return to work of patients. Overall optimal performance was also related to a small but significant higher level of satisfaction with care, both for patients and physicians.

Conclusion:Quality of occupational rehabilitation of cancer survivors can be improved substantially, especially with regard to communication between physicians and continuity of care. There is a need for the development of more effective rehabilitation procedures which should be evaluated in a randomised controlled trial.
FACTORIZATION IN EXCLUSIVE AND SEMI-INCLUSIVE HEAVY FLAVOR DECAYS AND EFFECTIVE THEORIES FOR MASSLESS PARTICLES
Authors: AGLIETTI UGO , CORBÒ GUIDO
Published: April 2003

We prove factorization in the semi-inclusive decay B → D(*) + jet using the Large Energy Effective Theory (LEET). It is also shown that the LEET is unable to consistently describe exclusive processes, such as the decay B → D(*) + π(ρ), and therefore also related properties such as factorization. The reason is an oversimplification of transverse momentum dynamics. We present a variant of the LEET, i.e. a new effective theory for massless particles, the [Formula: see text], which properly takes into account transverse momentum dynamics and is the natural framework to study exclusive nonleptonic decays. The transition from the LEET to the [Formula: see text] is analogous to the replacement of geometrical optics with physical optics, the latter taking into account diffraction to a first approximation. A qualitative argument is presented in favor of factorization in the exclusive nonleptonic decays using the [Formula: see text]. Finally, it is shown that the collinear instability of the LEET disappears when semi-inclusive observables are considered.
HARMONIC POLYLOGARITHMS
Authors: REMIDDI E. , VERMASEREN J. A. M.
Published: April 2003

The harmonic polylogarithms (hpl's) are introduced. They are a generalization of Nielsen's polylogarithms, satisfying a product algebra (the product of two hpl's is in turn a combination of hpl's) and forming a set closed under the transformation of the arguments x=1/z and x=(1-t)/(1+t). The coefficients of their expansions and their Mellin transforms are harmonic sums.
BASICS OF BRST QUANTIZATION ON INNER PRODUCT SPACES
Authors: MARNELIUS ROBERT , SANDSTRÖM NICLAS
Published: April 2003

There is an elaborated abstract form of BRST quantization on inner product spaces within the operator formalism which leads to BRST-invariant states of the form [Formula: see text] where ψ is a gauge fixing fermion, and where |ϕ> is a BRST-invariant state determined by simple Hermitian conditions. These state representations are closely related to the path integral formulation. Here we analyse the basics of this approach in detail. The freedom in the choice of ψ and |ϕ> as well as their properties under gauge transformations are explicitly determined for simple Abelian models. In all considered cases SL(2,R) is shown both to be a natural extended gauge symmetry and to be useful to determine |ph>. The results are also applied to non-Abelian models.
ELECTROMAGNETIC CORRECTIONS TO SUPERCONDUCTING COSMIC STRING EQUATION OF STATE AND VORTON STABILITY
Authors: MARTIN XAVIER
Published: April 2003

Electromagnetic self-interaction of a superconducting string is, in general, a subdominant dynamical process and was therefore ignored in initial investigations of superconducting string dynamics such as equilibrium states and their stability. The existence of stable equilibrium states is an important result which allows for loop accumulation in a superconducting string network and a strong bound on the string formation energy scale. It has recently been shown that first order electromagnetic self-interaction could be taken into account by a simple renormalization of the string equation of state. In this paper, the impact of this first order correction on the equilibrium equations of loops and on their stability is investigated as well as their dependence on the various parameters of the problem. The statistical properties of the vorton population are also examined.
BLUESHIFTED QUASARS ASSOCIATED WITH NEARBY GALAXIES?
Authors: BASU D. , HAQUE-COPILAH S. , VALTONEN M.
Published: April 2003

It is possible that supermassive black holes are ejected from centers of galaxies at high speeds. If the ejection happens in a nearby galaxy, then some black holes will travel towards us and may appear quasar-like with a blueshifted spectrum due to the Doppler effect. But quasar spectra are as a rule interpreted as having been redshifted even when there is an equally good or better case for a blueshifted spectrum. Here we study the quasars which are apparently associated with galaxies. We look for alternative identification for the spectral lines reported in the quasar spectra and offer blueshift values whenever it is consistent with the available information. We present a list of five candidates predicting the lines for future observation to confirm blueshifts. We also present a composite IR spectra which can be adjoined to existing composite spectra of lines in the optical and the UV region. We suggest that many of these objects are much less massive satellite bodies which have been ejected from nearby galaxies during binary black hole mergers.
MORE EVIDENCE FOR THE WDVV EQUATIONS IN ${\mathcal N} = 2$ SUSY YANG–MILLS THEORIES
Authors: MARSHAKOV A. , MIRONOV A. , MOROZOV A.
Published: April 2003

We consider 4D and 5D [Formula: see text] supersymmetric theories and demonstrate that in general their Seiberg–Witten prepotentials satisfy the Witten–Dijkgraaf–Verlinde–Verlinde (WDVV) equations. General proof for the Yang–Mills models (with matter in the first fundamental representation) makes use of the hyperelliptic curves and underlying integrable systems. A wide class of examples is discussed; it contains few understandable exceptions. In particular, in the perturbative regime of 5D theories, in addition to naive field theory expectations some extra terms appear, as happens in heterotic string models. We consider also the example of the Yang–Mills theory with matter hypermultiplet in the adjoint representation (related to the elliptic Calogero–Moser system) when the standard WDVV equations do not hold.
PATH INTEGRAL SOLUTION OF NONCENTRAL POTENTIAL
Authors: MANDAL BHABANI PRASAD
Published: April 2003

We have studied the path integral solution of a system of particle moving in a certain class of noncentral potential without using the Kustannheimo–Stiefel transformation. The Hamiltonian of the system has been converted to a separable Hamiltonian of Liouville type in parabolic coordinates and has further reduced to a Hamiltonian corresponding to two two-dimensional simple harmonic oscillators. The energy spectrum for this system is calculated analytically. The Hartmann ring-shaped potential and compound Coulomb plus the Aharanov–Bohm potential have also been studied as special cases.
THE EINSTEIN–CARTAN–MAXWELL THEORY WITH SCALAR FIELD THROUGH A FIVE-DIMENSIONAL UNIFICATION
Authors: KOHLER CHRISTOPHER
Published: April 2003

A modification of Kaluza–Klein theory is proposed in which, as a result of a symmetry breaking, five-dimensional space–time is partially parallelized implying the appearance of torsion fields. A naturally chosen action functional leads to the Einstein–Cartan–Maxwell theory where the electromagnetic field strength is represented by the fifth component of the torsion two-form. Incorporation of a scalar field reveals that four-dimensional space–time torsion is not induced by the scalar field.
WEAK MATRIX ELEMENTS AND |Vcb| IN HQEFT
Authors: WANG W. Y. , WU Y. L. , YAN Y. A.
Published: April 2003

The heavy quark effective field theory (HQEFT) containing both effective "quark fields" and "antiquark fields" is investigated in detail. By integrating out (but not neglecting) the effective antiquark fields, we present a new formulation of effective theory which differs from the usual heavy quark effective theory (HQET) and exhibits valuable features because of the inclusion of the contributions from the antiquark fields. Matrix elements of vector and axial vector heavy quark currents between pseudoscalar and vector mesons containing a heavy quark (b or c) are then evaluated systematically up to the order of [Formula: see text] and parametrized by a set of universal form factors. With a consistent normalization condition between the effective heavy hadron states, the form factors at zero recoil are related to the ground state meson masses, which enables us to estimate the values of form factors at zero recoil. In particular, Luke's theorem comes out automatically in the new formulation of HQEFT without the need of imposing the equation of motion [Formula: see text]. Consequently, the differential decay rates of both B → D*lν and B→Dlν do not receive 1/mQ order corrections at zero recoil, which is not the case in the usual HQET. Thus we quote that the Cabibbo–Kobayashi–Maskawa matrix element |Vcb| can nicely be extracted from either of these two exclusive semileptonic decays at the order of [Formula: see text]. Our estimates for |Vcb| are presented.
THE EQUIVALENCE POSTULATE OF QUANTUM MECHANICS
Authors: FARAGGI ALON E. , MATONE MARCO
Published: April 2003

The removal of the peculiar degeneration arising in the classical concepts of rest frame and time parametrization is at the heart of the recently formulated equivalence principle (EP). The latter, stating that all physical systems can be connected by a coordinate transformation to the free one with vanishing energy, univocally leads to the quantum stationary HJ equation (QSHJE). This is a third order nonlinear differential equation which provides a trajectory representation of quantum mechanics (QM). The trajectories depend on the Planck length through hidden variables which arise as initial conditions. The formulation has manifest p-q duality, a consequence of the involutive nature of the Legendre transformation and of its recently observed relation with second order linear differential equations. This reflects in an intrinsic ψD-ψ duality between linearly independent solutions of the Schrödinger equation. Unlike Bohm's theory, there is a nontrivial action even for bound states and no pilot waveguide is present. A basic property of the formulation is that no use of any axiomatic interpretation of the wave function is made. For example, tunneling is a direct consequence of the quantum potential which differs from the Bohmian one and plays the role of particle's self-energy. Furthermore, the QSHJE is defined only if the ratio ψD/ψ is a local homeomorphism of the extended real line into itself. This is an important feature as the L2(ℝ) condition, which in the Copenhagen formulation is a consequence of the axiomatic interpretation of the wave function, directly follows as a basic theorem which only uses the geometrical gluing conditions of ψD/ψ at q=±∞ as implied by the EP. As a result, the EP itself implies a dynamical equation that does not require any further assumption and reproduces both tunneling and energy quantization. Several features of the formulation show how the Copenhagen interpretation hides the underlying nature of QM. Finally, the nonstationary higher dimensional quantum HJ equation and the relativistic extension are derived.
DYNAMICAL BOSON FIELD IN THE NONLINEAR SPINOR THEORY
Authors: NOVELLO M. , ARCURI R. C.
Published: April 2003

We show that a class of boson fields can be described by a composite structure consisting of self-interacting spinors. We present a model for such bosonization and some perspectives concerning the consequences of such property.
PROTON DECAY, BLACK HOLES, AND LARGE EXTRA DIMENSIONS
Authors: ADAMS FRED C. , KANE GORDON L. , MBONYE MANASSE , PERRY MALCOLM J.
Published: April 2003

We consider proton decay in theories that contain large extra dimensions. If virtual black hole states are allowed by the theory, as is generally the case, then proton decay can proceed via virtual black holes. The experimental limits on the proton lifetime place strong constraints on the quantum gravity scale M qg (the effective Planck mass). For most theories, this implies a lower bound of M qg >1016 GeV. The corresponding bound on the size of large extra dimensions is ℓ<106/n×10-30 cm, where n is the number of such dimensions. Regrettably, for most theories this limit rules out the possibility of observing large extra dimensions at accelerators or in millimeter scale gravity experiments. Conversely, proton decay could be dominated by virtual black holes, providing an experimental probe to study stringy quantum gravity physics.
PARTON SHOWERS BEYOND THE LEADING ORDER: A FACTORIZATION APPROACH
Authors: HAUTMANN F.
Published: April 2003

We discuss recent work on methods for incorporating nonleading QCD corrections in parton shower algorithms.
WW CROSS SECTIONS AND W BRANCHING FRACTIONS IN L3
Authors: MALGERI LUCA
Published: April 2003

The measurements of W-pair cross sections performed by the L3 experiment at the LEP collider are herein reported. The statistics collected in the period 1996-2000 amounts to more than 8000 events distributed over a large center-of-mass energy range: 161–208 GeV. From the cross section measurements, also the W branching fractions in leptons and hadrons are derived with a percent precision: BR ( W → qq) = 68.47 ± 0.49 ± 0.33% and BR ( W → ℓν) = 10.51 ± 0.16 ± 0.11%. The improving statistical accuracy of the measurements is now approaching the systematic uncertainties. Further studies, necessary also for the W mass determination, will be needed in the near future to keep them under control.
MEASUREMENT AND INTERPRETATION OF LEPTON-PAIR PRODUCTION AT LEP2 ENERGIES
Authors: BEHRMANN ANETTE
Published: April 2003

A preliminary analysis of the lepton-pair production in e+e- annihilations at LEP2 center-of-mass energies using the data collected between 130 GeV and LEP2 highest energies (i.e. exceeding 205 GeV) with the DELPHI detector is presented. The values obtained for the cross-sections and forword-backward asymmetries are used to test the Standard Model predictions and to derive limits for possible new physics phenomena beyond it.
QCD FACTORIZATION IN HADRONIC B DECAYS
Authors: NEUBERT MATTHIAS
Published: April 2003

We review recent advances in the theory of strong-interaction effects and final-state interaction in hadronic weak decays of heavy mesons. In the heavy-quark limit, the amplitudes for most nonleptonic, two-body B decays can be calculated from first principles and expressed in terms of semileptonic form factors and light-cone distribution amplitudes. We summarize the main features of this novel QCD factorization and discuss its phenomenological applications to the charmless decays B→π K and B→ππ.
$D^0 - \overline{D^0}$ Mixing and D0→K-π+π0 Resonant Substructure Results from CLEO
Authors: Palmer Mark A.
Published: April 2003

The CLEO Collaboration has an active charm physics effort underway using 14fb-1 of CLEO II and CLEO II.V data. A recent analysis of the time dependence of the 'wrong-sign' decay D0→K+ π- has placed limits on x′ and y′, the amplitudes that describe mixing in the D0 system. The 95% CL limits, with no assumptions about CP violation, are (1/2)x′2 < 0.041% and -5.8% < y′ < 1.0%. Measurements of D0 decay rates to CP eigenstates, D0→K- K+ and D0→π-π+, provide preliminary CP asymmetry measurements [Formula: see text] and [Formula: see text]. A third analysis provides the first preliminary evidence for the decay D0→K+π- π0. Finally, a new Dalitz analysis of the decay D0→K-π+ π0 gives preliminary evidence for several new resonance contributions in this decay and also requires the presence of a significant non-resonant component.
LIGHT QUARK MASSES FROM QUENCHED LATTICE QCD SIMULATIONS WITH DOMAIN WALL QUARKS
Authors: WINGATE MATTHEW
Published: April 2003

Values for the strange quark mass and average up/down mass have been obtained from quenched lattice QCD simulations using the domain wall fermion action. This discretization preserves the properties of flavor and chiral symmetry at nonzero lattice spacing. Results are shown for two values of the lattice spacing. The mass renormalization constant is computed nonperturbatively.
MEASUREMENT OF THE KL→μ+μ-γ BRANCHING RATIO AND FORM FACTOR FROM KTeV
Authors: QUINN BREESE
Published: April 2003

We report on the analysis of the rare decay KL→μ+μ-γ using the 1997 data from the KTeV experiment at Fermilab. A total of 9327 candidate events are observed with 2.4% background, representing a factor of 40 increase in statistics over the current world sample. We find that BR(KL→μ+μ-γ)=(3.66±0.04stat±0.07syst)×10-7. The form factor parameter αK* is measured to the [Formula: see text]. We make the first measurement of the parameter α from the D'Ambrosio, Isidori, and Portolés form factor, finding α=-1.53±0.09. This measurement of α limits the CKM parameter ρ>-0.2.
A General MSSM Parameter Scan
Authors:   On behalf of the DELPHI Collaboration., SOPCZAK ANDRÉ
Published: April 2003

The excluded tan β range and Higgs boson mass region in the framework of the Minimal Supersymmetric extension of the Standard Model (MSSM) depend on several parameters. The Higgs boson masses, cross-sections and branching fractions have been determined including two-loop diagrammatic calculations. The limit obtained with a more general scan over the parameter space of the MSSM are compared with those in the so-called benchmark scenario. The combination of the searches for Higgs particles in the 1999 data collected by the DELPHI collaboration at center-of-mass energies between 191.6 and 201.7 GeV allows stringent limits to be set in combination with previous DELPHI results. In addition, an interpretation in the framework of the general MSSM scan of the 2000 LEP data at the hightest energies between 201.7 and 209.0 GeV is given. We show that the current data for the HZ and hA production can be comfortably accommodated in the MSSM.
μ PROBLEM, SO(10) SUSY GUT AND HEAVY GLUINO LSP
Authors: MAFI ARASH
Published: April 2003

we present a solution to the μ problem in an SO(10) supersymmetric grand unified (SUSY GUT) model with gauge mediated (GMSB) and D-term supersymmetry breaking. A Peccei-Quinn (PQ) symmetry is broken at the messenger scale and enables the generation of the μ term. The invisible axion (Goldstone boson of PQ symmetry breaking) is a cold dark matter candidate. At low energy, our model leads to a phenomenologically acceptable version of the minimal supersymmetric standard model (MSSM) with novel particle phenomenology. Either the gluino or the gravitino is the lightest supersymmetric particle (LSP). The phenomenological constraints on the model result in a Higgs with mass ~ 86 – 91 GeV and tan β ~ 9 – 14.
LIMITS ON QUARK COMPOSITENESS FROM HIGH ENERGY JETS IN ${\bar P}P$ COLLISIONS AT 1.8 TEV
Authors: ANDREW GREEN J. , BERTRAM IAIN , HAUPTMAN JOHN
Published: April 2003

Events in [Formula: see text] collisions at 1.8 TeV with total transverse energy exceeding 500 GeV are used to set limits on quark substructure. The data are consistent with next-to-leading order QCD calculations. We set a lower limit of 2.0 TeV at 95% confidence on the energy scale ΛLL for compositeness in quarks, assuming a model with a left-left isoscalar contact interaction term. The limits on ΛLL are found to be insensitive to the sign of the interference term in the Lagrangian.
QUANTUM GRAVITATIONAL EFFECTS AND THE COMPACTIFICATION SCALE IN THE HETEROTIC SUPERSTRING THEORY
Authors: POLLOCK M. D.
Published: April 2003

It is known that quantum gravitational effects due to virtual black holes and wormholes can exert an important influence by violating global symmetries. These processes have recently been investigated by Kallosh et al., who found, for the heterotic superstring theory, that there is a sufficient suppression of deleterious effects via the Euclidean action S E from the presence of higher-derivative terms occurring as a topological invariant, the Euler characteristic χ, regardless of the precise details of the underlying wormhole solution. Here, we consider this result further, arguing, in the absence of inflation, that there are no large wormholes in the heterotic superstring theory for which the wormhole action per se is large enough, topological suppression being the only possibility. The model-independent superstring axion may be susceptible to these corrections, because, as shown by Witten, it possesses a non-linearly realized, global U(1) symmetry, being a real scalar field coupled to the anomalous term [Formula: see text] from the outset, and they are relevant to the R-parity symmetry. Allowing for the unknown effect of the black holes, however, we conjecture that these quantum gravitational effects produce no observable consequences.
HAMILTON–JACOBI APPROACH TO PRE-BIG BANG COSMOLOGY AT LONG WAVELENGTHS
Authors: SAYGILI K.
Published: April 2003

We apply the long-wavelength approximation to the low-energy effective string action in the context of the Hamilton–Jacobi theory. The Hamilton–Jacobi equation for the effective string action is explicitly invariant under scale factor duality. We present the leading-order, general solution of the Hamilton–Jacobi equation. The Hamilton–Jacobi approach yields a solution consistent with the Lagrange formalism. The momentum constraints take an elegant, simple form. Furthermore, this general solution reduces to the quasi-isotropic one, if the evolution of the gravitational radiation is neglected. Duality transformation for the general solution is written as a coordinate transformation in an abstract field space.
IRREDUCIBLE ANTIFIELD BRST–ANTI-BRST FORMALISM FOR REDUCIBLE GAUGE THEORIES
Authors: BIZDADEA C. , NEGRU I. , SALIU S. O.
Published: April 2003

In this paper we develop an irreducible antifield BRST–anti-BRST formalism for reducible gauge theories.
EXACTLY SOLVABLE DYNAMICAL SYSTEMS IN THE NEIGHBORHOOD OF THE CALOGERO MODEL
Authors: HASCHKE OLIVER , RÜHL WERNER
Published: April 2003

The Hamiltonian of the N-particle Calogero model can be expressed in terms of generators of a Lie algebra for a definite class of representations. Maintaining this Lie algebra, its representations, and the flatness of the Riemannian metric belonging to the second order differential operator, the set of all possible quadratic Lie algebra forms is investigated. For N = 3 and N = 4 such forms are constructed explicitly and shown to correspond to exactly solvable Sutherland models. The results can be carried over easily to all N.
THE STRUCTURE OF ADS BLACK HOLES AND CHERN–SIMONS THEORY IN 2 + 1 DIMENSIONS
Authors: FERNANDO SHARMANTHIE , MANSOURI FREYDOON
Published: April 2003

We study anti-de Sitter black holes in 2 + 1 dimensions in terms of Chern–Simons gauge theory of the anti-de Sitter group coupled to a source. Taking the source to be an anti-de Sitter state specified by its Casimir invariants, we show how all the relevant features of the black hole are accounted for. The requirement that the source be a unitary representation leads to a discrete tower of excited states which provide a microscopic model for the black hole.
KLEIN TUNNELLING AND THE KLEIN PARADOX
Authors: CALOGERACOS A. , DOMBEY N.
Published: April 2003

The Klein paradox is reassessed by considering the properties of a finite square well or barrier in the Dirac equation. It is shown that spontaneous positron emission occurs for a well if the potential is strong enough. The vacuum charge and lifetime of the well are estimated. If the well is wide enough, a seemingly constant current is emitted. These phenomena are transient whereas the tunnelling first calculated by Klein is time-independent. Klein tunnelling is a property of relativistic wave equations, not necessarily connected with particle emission. The Coulomb potential is investigated in this context: it is shown that a heavy nucleus of sufficiently large Z will bind positrons. Correspondingly, it is expected that as Z increases the Coulomb barrier will become increasingly transparent to positrons. This is an example of Klein tunnelling.
FLOW OF THE COARSE GRAINED FREE ENERGY FOR CROSSOVER PHENOMENA
Authors: BORNHOLDT S. , BÜTTNER P. , TETRADIS N. , WETTERICH C.
Published: April 2003

The critical behavior of a system of two coupled scalar fields in three dimensions is studied within the formalism of the effective average action. The fixed points of the system are identified and the crossover between them is described in detail. Besides the universal critical behavior, the flow of the coarse grained free energy also describes the approach to scaling.
DYNAMICAL LINKED CLUSTER EXPANSIONS: A NOVEL EXPANSION SCHEME FOR POINT–LINK–POINT INTERACTIONS
Authors: MEYER-ORTMANNS HILDEGARD , REISZ THOMAS
Published: April 2003

Dynamical linked cluster expansions are linked cluster expansions with hopping parameter terms endowed with their own dynamics. This amounts to a generalization from two-point to point–link–point interactions. We develop an associated graph theory with a generalized notion of connectivity and describe an algorithmic generation of the new multiple-line graphs. We indicate physical applications to spin glasses, partially annealed neural networks and SU (N) gauge Higgs systems. In particular the new expansion technique provides the possibility of avoiding the replica trick in spin glasses. We consider variational estimates for the SU(2) Higgs model of the electroweak phase transition. The results for the transition line, obtained by dynamical linked cluster expansions, agree quite well with corresponding high precision Monte Carlo results.
CONSTRAINTS ON THE SU(5)C × SU(2)L × U(1)′ MODEL FROM LEP DATA
Authors: SARKAR SASWATI , RAY ASIM K. , SARKAR UTPAL
Published: April 2003

We have determined constraints on the SU (5)C × SU (2)L × U (1)′ model in terms of the extra mixing angle ϕ in the neutral gauge boson sector and ΔρM, the deviation of the Standard Model ρ parameter from unity at the tree level, using the recent precision measurements at LEP on electroweak parameters at the Z peak. The lower bound of the extra Z′ boson mass has also been determined.
CLONING SO(N) LEVEL 2
Authors: SCHELLEKENS A. N.
Published: April 2003

For each N an infinite number of conformal field theories is presented that has the same fusion rules as SO (N) level 2. These new theories are obtained as extensions of the chiral algebra of SO (NM2) level 2, and correspond to new modular invariant partition functions of these theories. A one-to-one map between the c=1 orbifolds of radius R2=2r and Dr level 2 plays an essential role.
PROBING GAUGE STRING FORMATION IN A SUPERCONDUCTING PHASE TRANSITION
Authors: RUDAZ SERGE , SRIVASTAVA AJIT M. , VARMA SHIKHA
Published: April 2003

Superconductors are the only experimentally accessible systems with spontaneously broken gauge symmetries which support topologically nontrivial defects, namely string defects. We propose two experiments whose aim is the observation of the dense network of these strings thought to arise, via the Kibble mechanism, in the course of a spontaneous symmetry breaking phase transition. We suggest ways to estimate the order of magnitude of the density of flux tubes produced in the phase transition. This may provide an experimental check for the theories of the production of topological defects in a spontaneously broken gauge theory, such as those employed in the context of the early Universe.
SOLUTIONS OF A DIRAC HYDROGENLIKE MESON AND SCALAR CONFINEMENT AT LOW ORBITAL ANGULAR MOMENTUM STATES
Authors: AVILA M. A.
Published: April 2003

Wave functions of a heavy-light quark [Formula: see text] system described by a covariant Dirac Hamiltonian are analyzed. By assuming that the confinement potential is a Lorentz scalar (S), the slope of the Isgur–Wise function is calculated at zero recoil point. The result obtained is ξ′(1)= -0.93± 0.05. This means that the solutions are perfectly consistent. If relativistic corrections in the light quark wave functions are included the result is ξ′(1)=-1.01± 0.04. From heavy-light data this suggests that if relativistic effects are considered, scalar confinement is reliable in low orbital angular momentum states.
HIGGS FIELD AND LOCALIZATION PROBLEM
Authors: CAMACHO A. , DEHNEN H.
Published: April 2003

We analyze the role that the excited states of the Higgs field could play in a possible solution to the so-called localization problem of Quantum Theory. We seek a solution to the aforementioned point without introducing additional fundamental constants or extra hypotheses, as has been done in previous works. The electron and Higgs field do indeed have solitonic solutions. This last feature renders, in the one-dimensional case, a solution to the localization problem.
ANALYSIS OF NEUTRINO OSCILLATION IN THREE-FLAVOR NEUTRINOS
Authors: SAKAI T. , INAGAKI O. , TESHIMA T.
Published: April 2003

We analyze the solar, terrestrial and atmospheric neutrino experiments including SuperKamiokande data using the three-flavor neutrinos framework and obtain the allowed region for parameters [Formula: see text]. In solar neutrino experiments, we obtain the large angle solution [Formula: see text] and small angle solution (3×10-6-1.2×10-5 eV 2, 0.003-0.01) for θ13=0°-20°. From the terrestrial and atmospheric neutrino experiments including the sub-GeV and multi-GeV zenith angle dependence in SuperKamiokande 535 days data, we found that the νμ-ντ mixing is large and the range of [Formula: see text] as 0.02~0.0002  eV 2. There is no significant difference between large θ12 angle solution and small one.
ON JORDANIAN Uh,α(gl(2)) ALGEBRA AND ITS T MATRICES VIA A CONTRACTION METHOD
Authors: CHAKRABARTI R. , QUESNE C.
Published: April 2003

The [Formula: see text] matrices of the Jordanian U h( sl (2)) algebra at arbitrary dimensions may be obtained from the corresponding [Formula: see text] matrices of the standard q-deformed U q( sl (2)) algebra through a contraction technique. By extending this method, the colored two-parametric (h, α) Jordanian [Formula: see text] matrices of the U h,α( gl (2)) algebra may be derived from the corresponding colored [Formula: see text] matrices of the standard (q, λ)-deformed U q,λ( gl (2)) algebra. Moreover, by using the contraction process as a tool, the colored [Formula: see text] matrices for arbitrary (j, z) representations of the Jordanian Fun h,α( GL (2)) algebra may be extracted from the corresponding [Formula: see text] matrices of the standard Fun q,λ( GL (2)) algebra.
GAUGE THEORY OF GRAVITY REQUIRES MASSIVE TORSION FIELD
Authors: KÜHNE RAINER W.
Published: April 2003

One of the greatest unsolved issues of the physics of this century is to find a quantum field theory of gravity. According to a vast amount of literature, unification of quantum field theory and gravitation requires a gauge theory of gravity which includes torsion and an associated spin field. Various models including either massive or massless torsion fields have been suggested. We present arguments for a massive torsion field, where the probable rest mass of the corresponding spin three gauge boson is the Planck mass.
QUARK CONFINEMENT AND COLOR TRANSPARENCY IN A GAUGE-INVARIANT FORMULATION OF QCD
Authors: CHEN LUSHENG , HALLER KURT
Published: April 2003

We examine a nonlocal interaction that results from expressing the QCD Hamiltonian entirely in terms of gauge-invariant quark and gluon fields. The interaction couples one quark color-charge density to another, much as electric charge densities are coupled to each other by the Coulomb interaction in QED. In QCD, this nonlocal interaction also couples quark color-charge densities to gluonic color. We show how the leading part of the interaction between quark color-charge densities vanishes when the participating quarks are in a color singlet configuration, and that, for singlet configurations, the residual interaction weakens as the size of a packet of quarks shrinks. Because of this effect, color-singlet packets of quarks should experience final state interactions that increase in strength as these packets expand in size. For the case of an SU(2) model of QCD based on the ansatz that the gauge-invariant gauge field is a hedgehog configuration, we show how the infinite series that represents the nonlocal interaction between quark color-charge densities can be evaluated nonperturbatively, without expanding it term-by-term. We discuss the implications of this model for QCD with SU(3) color and a gauge-invariant gauge field determined by QCD dynamics.
STRINGS, NONCOMMUTATIVE GEOMETRY AND THE SIZE OF THE TARGET SPACE
Authors: LIZZI FEDELE
Published: April 2003

We describe how the presence of the antisymmetric tensor (torsion) on the world sheet action of string theory renders the size of the target space a gauge noninvariant quantity. This generalizes the R ↔ 1/R symmetry in which momenta and windings are exchanged, to the whole O(d,d,ℤ). The crucial point is that, with a transformation, it is possible always to have all of the lowest eigenvalues of the Hamiltonian to be momentum modes. We interpret this in the framework of noncommutative geometry, in which algebras take the place of point spaces, and of the spectral action principle for which the eigenvalues of the Dirac operator are the fundamental objects, out of which the theory is constructed. A quantum observer, in the presence of many low energy eigenvalues of the Dirac operator (and hence of the Hamiltonian) will always interpreted the target space of the string theory as effectively uncompactified.
GENERAL VIRASORO CONSTRUCTION ON ORBIFOLD AFFINE ALGEBRA
Authors: EVSLIN J. , HALPERN M. B. , WANG J. E.
Published: April 2003

We obtain the orbifold Virasoro master equation (OVME) at integer order λ, which summarizes the general Virasoro construction on orbifold affine algebra. The OVME includes the Virasoro master equation when λ=1 and contains large classes of stress tensors of twisted sectors of conventional orbifolds at higher λ. The generic construction is like a twisted sector of an orbifold (with nonzero ground state conformal weight) but new constructions are obtained for which we have so far found no conventional orbifold interpretation.
AN INTEGRATED LINEAR TECHNIQUE FOR POSE ESTIMATION FROM DIFFERENT GEOMETRIC FEATURES
Authors: JI QIANG , COSTA MAURO S. , HARALICK ROBERT M. , SHAPIRO LINDA G.
Published: April 2003

Existing linear solutions for the pose estimation (or exterior orientation) problem suffer from a lack of robustness and accuracy partially due to the fact that the majority of the methods utilize only one type of geometric entity and their frameworks do not allow simultaneous use of different types of features. Furthermore, the orthonormality constraints are weakly enforced or not enforced at all. We have developed a new analytic linear least-squares framework for determining pose from multiple types of geometric features. The technique utilizes correspondences between points, between lines and between ellipse–circle pairs. The redundancy provided by different geometric features improves the robustness and accuracy of the least-squares solution. A novel way of approximately imposing orthonormality constraints on the sought rotation matrix within the linear framework is presented. Results from experimental evaluation of the new technique using both synthetic data and real images reveal its improved robustness and accuracy over existing direct methods.
EYE DETECTION USING OPTIMAL WAVELET PACKETS AND RADIAL BASIS FUNCTIONS (RBFs)
Authors: HUANG JEFFREY , WECHSLER HARRY
Published: April 2003

The eyes are important facial landmarks, both for image normalization due to their relatively constant interocular distance, and for post processing due to the anchoring on model-based schemes. This paper introduces a novel approach for the eye detection task using optimal wavelet packets for eye representation and Radial Basis Functions (RBFs) for subsequent classification ("labeling") of facial areas as eye versus non-eye regions. Entropy minimization is the driving force behind the derivation of optimal wavelet packets. It decreases the degree of data dispersion and it thus facilitates clustering ("prototyping") and capturing the most significant characteristics of the underlying (eye regions) data. Entropy minimization is thus functionally compatible with the first operational stage of the RBF classifier, that of clustering, and this explains the improved RBF performance on eye detection. Our experiments on the eye detection task prove the merit of this approach as they show that eye images compressed using optimal wavelet packets lead to improved and robust performance of the RBF classifier compared to the case where original raw images are used by the RBF classifier.
GAMES ARISING FROM INFINITE PRODUCTION SITUATIONS
Authors: TIMMER JUDITH , TIJS STEF , LLORCA NATIVIDAD
Published: April 2003

Situations involving the linear transformation of products (LTP) with an infinite number of transformation techniques are considered. It is shown that an optimal solution of the dual program of the profit "maximisation" problem exists under certain conditions. Moreover, this solution generates a core-element of the corresponding LTP game.
ON SOME PROPERTIES OF SUPERPOSITION OF OPTIMALITY PRINCIPLES FOR COOPERATIVE GAMES
Authors: CHISTYAKOV SERGEI V. , MIKHAJLOVA SVETLANA Y.
Published: April 2003

The aim of this paper is to study the properties of superposition of optimality principles depending on the properties of optimality principles, which it is formed from. Some sufficient conditions for quasiperfectness of superposition of two optimality principles are found. It is shown, in particular, that superposition of any optimality principle like min-max principle with any monotone and continuous optimality principle is a quasiperfect optimality principle.
EQUILIBRIUM STRATEGIES IN STOCHASTIC GAMES WITH ADDITIVE COST AND TRANSITION STRUCTURE
Authors: KÜENLE HEINZ-UWE
Published: April 2003

Two-person stochastic games with additive transition and cost structure and the criterion of expected total costs are treated. State space and action spaces are standard Borel, and unbounded costs are allowed. For the zero-sum case, it is shown that there are stationary deterministic εη-optimal strategies for every ε>0 and a certain weight function η if some semi-continuity and compactness conditions are fulfilled. Using these results, the existence of so-called quasi-stationary deterministic εη-equilibrium strategy pairs under corresponding conditions is proven.
VIBRATIONS OF ELASTIC BOTTOM PLATE OF A SEALED RECTANGULAR CONTAINER FULLY FILLED WITH LIQUID
Authors: ZHOU D. , CHEUNG Y. K.
Published: April 2003

The hydroelastic vibration of a rectangular plate, which is an elastic part of the rigid bottom of a sealed rectangular container fully filled with liquid, is studied. Both the vertical walls and the horizontal top of the container are rigid. An analytical-Ritz method is developed to analyze the dynamic behavior of the liquid-plate interaction. Firstly, the exact expression of velocity potential of the liquid is derived by the method of separation of variables. The unknown coefficients in the solution are determined by the liquid-plate interface condition in a form of integrals including the unknown dynamic deformation of the plate. Secondly, the total energy of the liquid-plate system is derived. Using Green's theorem, the volume integral of liquid kinetic energy is transformed into a surface integral surrounding the liquid domain. Thirdly, by expanding the wet modes of the plate into a series of beam vibrating functions and using the Ritz method, the eigenvalue equation of the liquid-plate system is obtained. Finally, the high accuracy and small computational effort are demonstrated by typical convergence studies. The effects of various parameters on eigenfrequencies of the liquid-plate system are discussed in detail.