bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibacterial Activity of Three Dental Liners
Authors: Eli Ilana , Cooper (Bril) Yifat , Ben‐Amar Ariel , Weiss Erwin
Published: March 2005

Purpose The purpose of the present study was to assess the antibacterial activity of the following three dental liners: Vitrebond (3M, St Paul, MN), Dycal (LD Caulk, Dentsply International, Milford, DE), and Life (Kerr, Romulus, MI).

Materials and Methods The test was based on a modification of the agar diffusion test in which samples were placed on agar plates previously inoculated with Streptococcus mutans and were removed after predetermined time periods. The material's effect on bacterial growth was evaluated.

Results Results show that Vitrebond has a strong antibacterial effect that was evident after 1 minute of direct contact with the inoculated bacteria. It was significantly more effective (P < .0001) than Dycal or Life.

Conclusions This method allows for the evaluation of the antibacterial effect of dental materials after different contact time periods between dental liners and bacteria.
Fabricating Low‐Fusing Metal Casts for More Accurate Implant Prosthodontics
Authors: Schneider Robert L. , Wee Alvin G.
Published: March 2005

An important factor that affects the clinical success of dental implants is the way stresses are transferred to the bone via the implant framework and fixture. An ill‐fitting implant framework will contribute to these stresses and may result in catastrophic failure of the prosthesis or one of the components and/or fixtures, in addition to possible alveolar bone loss. Many factors may contribute to the difficulty of achieving a passive fit on a complete‐arch implant framework. A technique for producing an accurate master cast by using a low‐fusing metal is described. The low‐fusing metal is dimensionally more accurate than conventional gypsum products. The technique does not require a significant change from conventional chairside and laboratory procedures for complete‐arch master cast impressions, and should result in a more passively fitting framework.
Risk factors associated with migraine or chronic daily headache in out‐patients with major depressive disorder
Authors: Hung C.‐I. , Wang S.‐J. , Hsu K.‐H. , Juang Y.‐Y. , Liu C.‐Y.
Published: March 2005

Objective:  This study investigated independent comorbidities and factors associated with migraine and chronic daily headache (CDH) in out‐patients with major depressive disorder (MDD).

Method:  Consecutive psychiatric out‐patients fulfilling the DSM‐IV criteria of MDD were enrolled. Headaches were diagnosed based on the criteria proposed by the second edition of the International Classification of the Headache Disorders. Psychiatric comorbidities were checked using the Mini International Neuropsychiatric Interview. Scores of the Hamilton Depression Rating Scale (HAMD) and duration of major depressive episodes (MDE) were evaluated. Multivariate logistic regression was used to decide risk factors.

Results:  One hundred and fifty‐one patients (34 men and 117 women) participated in the study, among which 73 (48.3%) reported a history of migraine and 32 (21.2%) reported CDH during this MDE. Higher HAMD scores, female gender, and chronic depression were independently associated with migraine or CDH.

Conclusion:  For MDD patients with a higher depressive severity and longer duration of MDE, especially female gender, surveillance of migraine and CDH might be indicated.
Mental disorders, disability and health service use amongst Vietnamese refugees and the host Australian population
Authors: Steel Z. , Silove D. , Chey T. , Bauman A. , Phan T. , Phan T.
Published: March 2005

Objective:  To compare the prevalence of common mental disorders, disability and health service utilization amongst Vietnamese refugees resettled in Australia for 11 years, with data obtained from a national survey of the host population.

Method:  A stratified multistage probability household survey of 1611 Vietnamese undertaken in the state of New South Wales was compared with data from 7961 Australian‐born respondents. Measures included the CIDI 2.1 and the MOS SF‐12.

Results:  The 12‐month prevalence of anxiety, depression and drug and alcohol dependence amongst Vietnamese was 6.1% compared with 16.7% amongst Australians. Vietnamese with a mental illness reported higher disability but exhibited similar levels of mental health consultation. The overall service burden of mental disorders was lower for the Vietnamese.

Conclusion:  The findings suggest that refugee groups resettled for some time in Western countries may show sound mental health adaptation and do not necessarily impose a burden on general or mental health services.
The psychiatrist's image in commercially available American movies
Authors: Gharaibeh N. M.
Published: March 2005

Objective:  To explore quantitatively how American movies portray psychiatrists/therapist.

Method:  A total of 106 movies were reviewed regarding how psychiatrists/therapists were portrayed. The psychiatrist's or therapist's sex, age, clinical competence and knowledge, boundary violations, attitude toward the patient, influence in the movie's events, treatment modality or modalities used, intervention's outcome, and therapeutic setting.

Results:  The psychiatrists/therapists tended to be males (71.2%), and (regardless of sex) middle‐aged (50.8%). Despite the general view of the psychiatrists/therapists as friendly (63.6%), there was an over‐representation of boundary violations. The percentage of total boundary violations was 44.9% of the cases portrayed and sexual violations accounted for 23.7%, while non‐sexual violations accounted for 30.5% (with 9.3% overlap). The appearance of clinical incompetence was 47.5%.

Conclusion:  The image of psychiatrists/therapists in commercially available movies is not flattering: close to one out of two violated boundaries, close to one out of four committed a sexual boundary violation, and the psychiatrist/therapist was as likely to be incompetent as competent. The bright point is that psychiatrists/therapists were depicted as more likely to be friendly.
Obsessive–compulsive disorder: a critical review of therapeutic perspectives
Authors: Schruers K. , Koning K. , Luermans J. , Haack M. J. , Griez E.
Published: March 2005

Objective:  Obsessive–compulsive disorder (OCD) is a chronic disabling disease with profound implications for social functioning. Thirty per cent of all patients with OCD show insufficient improvement with state‐of‐the‐art treatment. Conventional treatment and alternative treatment options for this population were investigated.

Method:  A selective review of the relevant scientific literature on OCD treatment and treatment resistance was conducted.

Results:  In addition to serotonin reuptake inhibitors (SRIs) and cognitive‐behavioural therapy, alternative monotherapies, SRI augmentation strategies with a variety of drugs and electroconvulsive therapy have shown results in individual cases, but no conclusive evidence has been found in placebo‐controlled trials. While studies investigating neurosurgery for refractory OCD show positive results, most of these studies have methodological shortcomings.

Conclusion:  Novel approaches currently under investigation that have shown promising effects for treatment‐resistant OCD include SRI augmentation with atypical antipsychotics and chronic deep brain stimulation, a new surgical technique. Placebo‐controlled trials for both treatment options will be needed to confirm preliminary findings.
A review of self‐management interventions for panic disorders, phobias and obsessive‐compulsive disorders
Authors: Barlow J. H. , Ellard D. R. , Hainsworth J. M. , Jones F. R. , Fisher A.
Published: March 2005

Objective:  To review current evidence for the clinical and cost‐effectiveness of self‐management interventions for panic disorder, phobias and obsessive‐compulsive disorder (OCD).

Method:  Papers were identified through computerized searches of databases for the years between 1995 and 2003, manual searches and personal contacts. Only randomized‐controlled trials were reviewed.

Results:  Ten studies were identified (one OCD, five panic disorder, four phobias). Effective self‐management interventions included cognitive‐behavioural therapy (CBT) and exposure to the trigger stimuli for phobias and panic disorders. All involved homework. There was evidence of effectiveness in terms of improved symptoms and psychological wellbeing when compared with standard care, waiting list or relaxation. Brief interventions and computer‐based interventions were effective for most participants. In terms of quality, studies were mainly based on small samples, lacked long‐term follow‐up, and failed to address cost‐effectiveness.

Conclusion:  Despite the limitations of reviewed studies, there appears to be sufficient evidence to warrant greater exploration of self‐management in these disorders.
Water Balance in PEM and Direct Methanol Fuel Cells
Authors: Izenson Michael G. , Hill Roger W.
Published: March 2005

Water management is a critical design issue for polymer electrolyte membrane (PEM) fuel cells, because the PEM must be maintained at the proper water content to remain ionically conducting without flooding the electrodes. Furthermore, portable PEM power systems should operate at water balance to minimize weight. This paper presents the basic design relationships that govern water balance in a PEM fuel cell. Specific calculations are presented based on data from hydrogen/air and direct methanol fuel cells currently under development for portable power systems. We will show how the water balance operating point depends on the cell operating parameters and show the sensitivity to off-design conditions.
Optimal SOFC Size Design for Minimal Cost of Electricity Achievement
Authors: Bove Roberto , Sammes Nigel M.
Published: March 2005

SOFC numerical simulations and experiments are a low cost method in achieving adequate performance to penetrate the market. Most of the efforts are at the present focused on components, single cells and stack performances and reliability improvements, while, at the same time, a lot of work is needed for optimal system configuration design. Simulation and experimental results conducted on a system level must provide a goal and scope of the single components system research, including fuel processing, fuel cells and all the balance of plant (BoP) components. In the present work a preliminary numerical simulation of a SOFC system is conducted, in order to establish the optimal stack size for minimal cost of electricity (CoE) achievements.
Simulation-Aided PEM Fuel Cell Design and Performance Evaluation
Authors: Wu Junxiao , Liu Qingyun
Published: March 2005

A multi-resolution fuel cell simulation strategy has been employed to simulate and evaluate the design and performance of hydrogen PEM fuel cells with different flow channels. A full 3D model is employed for the gas diffusion layer and a 1D+2D model is applied to the catalyst layer. Further, a quasi-1D method is used to model the flow channels. The cathode half-cell simulation was performed for three types of flow channels: serpentine, parallel, and interdigitated. Simulations utilized the same overall operating conditions. Comparisons of results indicate that the interdigitated flow channel is the optimal design under the specified operating conditions.
Oxygen Transport in YSZ∕LSM Composite Materials
Authors: Dhallu M. , Kilner J. A.
Published: March 2005

To date, a number of ceramic oxides with the perovskite structure have been proposed as membrane materials for the selective separation of oxygen and the partial oxidation of hydrocarbons due to their high oxygen permeation fluxes. In contrast, their instability under an oxygen pressure gradient and consequent lattice expansion has been shown to be the cause of their decomposition over time, thus generally limiting their use to oxidizing environments. This has led the search for possible materials to be diverted towards alternatives such as composites. In this work, we aim to further our understanding of oxygen transport in composite materials by continuing our studies on a model mixed conducting system of Zr0.84Y0.16O1.92 (YSZ) and (La0.8Sr0.2)0.98MnO3±δ (LSM) using the isotope exchange depth profiling method in conjunction with secondary ion mass spectrometry (SIMS). The measured effective tracer diffusion coefficients were in the range 10−8to10−7cm2∕s and the effective surface exchange coefficients in the range 10−8to10−5cm∕s. The activation enthalpies for oxygen diffusion and surface exchange processes were calculated to be 113 and 318kJ∕mol, respectively.
Stability and Reactivity of LSGM Electrolytes With Nickel-Based Ceramic Cathodes
Authors: Munnings C. N. , Skinner S. J. , Amow G. , Whitfield P. S. , Davidson I. J.
Published: March 2005

The surface of La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM 9182) has been examined through the use of secondary-ion mass spectrometry before and after surface modification by mechanical polishing. It was found that the cation stoichiometry varied at the surface in both cases. The effect of this change on the performance of the cathode material La2NiO4+δ was assessed through ac impedance spectroscopy of symmetrical cells prepared by depositing La2NiO4+δ on the surface of pellets of La0.9Sr0.1Ga0.8Mg0.2O3−δ. An improvement in the cathode performance of these cells at temperatures above 500°C was found on electrolytes with elevated levels of strontium and magnesium at the surface.
A Multiphysics Modeling Study of (Pr0.7Sr0.3)MnO3±δ∕8mol% Yttria-Stabilized Zirconia Composite Cathodes for Solid Oxide Fuel Cells
Authors: An Ke , Reifsnider Kenneth L.
Published: March 2005

Solid oxide fuel cells (SOFCs) are expected to be a future power source. Simulation analyses of SOFCs can help to understand well the interactive functions among the multiphysics phenomena in the SOFC system. A three-dimensional multiphysics finite-element model was used to simulate the performance of a half-cell SOFC with (Pr0.7Sr0.3)MnO3±δ∕8mol% yttria-stabilized zirconia (8YSZ) composite cathode on one side of the 8YSZ electrolyte before and after aging. Multiphysics phenomena in the SOFC were considered in the modeling. The current/voltage curves simulated matched the experimental data before and after aging. The average current density was found to have a linear relationship to the logarithm of the effective exchange current density. The effect of the effective ionic conductivity of the composite cathode was more apparent for small total effective ionic conductivity values than for large ones.
Modeling the Performance of Flattened Tubular Solid Oxide Fuel Cell
Authors: Bharadwaj A. , Archer D. H. , Rubin E. S.
Published: March 2005

In this paper, we develop a computational model to predict the electrical performance of the flattened tubular solid oxide fuel cell (SOFC) designed by Siemens Westinghouse Corporation. This design is an improvement over the conventional cylindrical SOFC and allows higher power densities. We modeled the current transport in a cross section of the cell for a given cell operating voltage and local Nernst voltage. We solved the resulting system of simultaneous nonlinear equations using n-dimensional Newton-Raphson algorithm. The output gives the current density distribution and also the total current at the cross section, which is used to obtain the total cell current (and power) for the given voltage. The results of the model are in good agreement with the experimental performance reported in literature.
On the definition of mass in classical physics
Authors: Goodinson P. A. , Luffman B. L.
Published: March 2005

An operational definition of mass in classical physics is presented by way of some table-top experiments with bodies.
A catastrophic toy
Authors: Rodewald Bernd , Schlichting Hans Joachim
Published: March 2005

We discuss a simple mechanical toy and show that it exhibits a catastrophe which is quite similar to a first-order phase transition.
Role of integrals of motion in closing an orbit
Authors: Mitra Abhas
Published: March 2005

A closed orbit can be thought of as a kind of symmetry of the dynamical system concerned. Consequently, one may explore the latent symmetry in the very form of the force law responsible for a closed orbit. This latent symmetry should manifest itself in the form of an integral of motion distinct from the ones which are already present in a central field. Pursuing this idea, it will be shown here that once an extra integral of motion is found, a closed orbit can be predicted.
Invariants of the electromagnetic field and electromagnetic waves
Authors: Salingaros Nikos
Published: March 2005

The three Lorentz invariant combinations of the electromagnetic field components are derived in a very transparent manner via the Clifford algebra. The third invariant is a combination of the potential and the field, and is not as well known as it deserves to be. As an application, recently proposed electromagnetic waves with E parallel to B are discussed. Using the three invariants, it is shown that Lorentz covariance is ill defined for such waves.
Simple demonstration of the Josephson effect
Authors: Walker I. R.
Published: March 2005

Apparatus which can be used to demonstrate the Josephson effect is described. It is simple enough to be assembled in an afternoon and is dependable enough to use in a lecture demonstration. Using a few pieces of niobium wire, an oscilloscope and signal generator, a storage dewar of liquid helium, and some easily obtainable parts, it is possible to see many of the effects which have made Josephson junctions such interesting and useful devices. These include lossless currents (the dc Josephson effect), hysteresis, and macroscopic quantum interference. Phenomena arising from the production of microwave energy when voltages are applied across a Josephson junction (the ac Josephson effect) can also be observed.
Demonstration of angular momentum coupling between rotating systems
Authors: Herrmann F. , Schmid G. Bruno
Published: March 2005

A simple arrangement is discussed which demonstrates ‘‘spin–spin’’ and ‘‘spin–orbit’’ coupling between rotating systems both with and without dissipation.
Relativity and relativism
Authors: Hammond John L.
Published: March 2005

It is widely assumed that relativity in physics lends credibility to forms of relativism outside of science. Though fallacious, this assumption has consequences which merit the concerned attention of persons in the science community, especially teachers of physics. The falseness of the assumption can be made apparent by several fairly simple considerations, appropriate for brief classroom presentation.
Reduced mass and orbit radius
Authors: McGervey John D.
Published: March 2005

Many textbooks contain misleading statements implying that the radius of the electron’s orbit in a one-electron atom or ion depends on the mass of the nucleus. It does not. The confusion arises because the symbol r, for relative coordinate, is sometimes incorrectly interpreted as the orbit radius. This confusion leads to incorrect answers to problems posed in these books.
Improving on the conventional presentation of molecular vibrations: Advantages of the pseudoharmonic potential and the direct construction of potential energy curves
Authors: Sage M. , Goodisman J.
Published: March 2005

Two improvements in the discussion of molecular vibrations are suggested. First, the pseudoharmonic potential possesses advantages over the harmonic: as a proper potential should, it has a larger force constant inside the equilibrium distance than outside and becomes infinite for zero distance. Its eigenvalues and eigenfunctions may be obtained in closed form either by the power series method or by manipulation of the Schrödinger equation into a standard form. Unlike the harmonic case, this is still true in the presence of a centrifugal potential. The second improvement involves a direct method of constructing a potential energy curve from the energy levels, rather than adjusting parameters in a potential so that calculated energy levels fit experimental values. The method, which involves the instructive semiclassical momentum, is illustrated for the harmonic and pseudoharmonic potentials, with an apparent paradox cleared up.
Central drift of freely moving balls on rotating disks: A new method to measure coefficients of rolling friction
Authors: Weltner Klaus
Published: March 2005

A ball rolling without slip on a rotating platform moves along stable circular orbits with respect to the laboratory frame of reference. As the radius of the circle approaches zero, the ball remains stationary in space. If rolling friction is taken into account, an unexpected phenomenon can be observed: The spinning ball drifts toward the center of rotation and the rate at which it does so can be used to measure the coefficient of rolling friction. When atop a rotating cone, the ball moves along a circle about the axis of rotation. Due to rolling friction, balls can even move on spirals uphill.
Resource letter HP-1: History of physics
Authors: Brush Stephen G.
Published: March 2005

This Resource Letter provides an introduction to the literature on the history of physics. Because of the overwhelming quantity of publications, the emphasis is on works covering broad topics and historical periods rather than on monographs dealing with special subjects or individual physicists, and on recent reference works that facilitate retrieval of more specialized information. The letter E after an item indicates elementary level or material of general interest to persons becoming informed in the field. The letter I, for intermediate level, indicates material of somewhat more specialized nature; and the letter A indicates rather specialized or advanced material. An asterisk (*) indicates those articles to be included in an accompanying Reprint Book.
A student experiment for accurate measurements of the Newtonian gravitational constant
Authors: Dousse J.-Cl. , Rhême Ch.
Published: March 2005

How can the Newtonian gravitational constant G at the 0.1% accuracy level be measured in a student experiment? This article may help the reader in answering this question. The described improvements of a preexisting apparatus should be applicable to most student laboratories. Results based on direct deflection and swing-time methods are presented. The corresponding sources of uncertainty and possible systematic errors are discussed.
Magnetic braking: Simple theory and experiment
Authors: Wiederick H. D. , Gauthier N. , Campbell D. A. , Rochon P.
Published: March 2005

A simple theory of magnetic braking in a thin metal strip is proposed. The predictions of the model are compared to experiment and good agreement is obtained. The experimental tests were conducted by spinning a thin aluminum disk of large radius between the pole pieces of an electromagnet. A field range of 0 to 150 mT was used.
Coulomb–Kepler problem and the harmonic oscillator
Authors: Chen Augustine C.
Published: March 2005

The three-dimensional Coulomb–Kepler problem is shown to be equivalent to a pair of coupled two-dimensional harmonic oscillators with the same angular momentum in classical mechanics by means of a Kustaanheimo–Stiefel transformation of coordinates and velocities. The constraint condition inherent in the transformation is shown to be related to the Runge–Lenz vector. The relationship between the action variables of the two systems is discussed. The equivalence is seen to result in the separability of the problem in parabolic coordinates.
The Cavendish experiment as Cavendish knew it
Authors: Clotfelter B. E.
Published: March 2005

The Cavendish experiment is always interpreted now as a measurement of G, the universal gravitational constant, but that is an interpretation that Cavendish did not make. He thought that he had measured the mean density of the Earth, and he was only one of many experimenters measuring the density of the Earth by many methods during the 18th century.
DILATON STABILIZATION IN BRANE GAS COSMOLOGY
Authors: BERNDSEN A. , CLINE J.
Published: March 2005

Brane Gas Cosmology is an M-theory motivated attempt to reconcile aspects of the standard cosmology based on Einstein's theory of general relativity. Dilaton gravity, when incorporating winding p-brane states, has verified the Brandenberger–Vafa mechanism —a string-motivated conjecture which explains why only three of the nine spatial dimensions predicted by string theory grow large. Further investigation of this mechanism has argued for a hierarchy of subspaces, and has shown the internal directions to be stable to initial perturbations. These results, however, are dependent on a rolling dilaton, or varying strength of Newton's gravitational constant GN. In these proceedings we show that it is not possible to stabilize the dilaton and maintain the stability of the internal directions within the standard Brane Gas Cosmology setup.
DARK ENERGY, DARK MATTER AND FERMION FAMILIES IN THE TWO MEASURES THEORY
Authors: GUENDELMAN E. I. , KAGANOVICH A. B.
Published: March 2005

A field theory is proposed where the regular fermionic matter and the dark fermionic matter are different states of the same "primordial" fermion fields. In regime of the fermion densities typical for normal particle physics, each of the primordial fermions splits into three generations identified with regular fermions. In a simple model, this fermion families birth effect is accompanied with the right lepton numbers conservation laws. It is possible to fit the muon to electron mass ratio without fine tuning of the Yukawa coupling constants. When fermion energy density becomes comparable with dark energy density, the theory allows new type of states - Cosmo-Low Energy Physics (CLEP) states. Neutrinos in CLEP state can be both a good candidate for dark matter and responsible for a new type of dark energy. In the latter case the total energy density of the universe is less than it would be in the universe free of fermionic matter at all. The (quintessence) scalar field is coupled to dark matter but its coupling to regular fermionic matter appears to be extremely suppressed.
DISTINGUISHING BARE QUARK STARS FROM NEUTRON STARS
Authors: JAIKUMAR P. , GALE C. , PAGE D. , PRAKASH M.
Published: March 2005

Observations to date cannot distinguish neutron stars from self-bound bare quark stars on the basis of their gross physical properties such as their masses and radii alone. However, their surface luminosity and spectral characteristics can be significantly different. Unlike a normal neutron star, a bare quark star can emit photons from its surface at super-Eddington luminosities for an extended period of time. We present a calculation of the photon bremsstrahlung rate from the bare quark star's surface, and indicate improvements that are required for a complete characterization of the spectrum. The observation of this distinctive photon spectrum would constitute an unmistakable signature of a strange quark star and shed light on color superconductivity at stellar densities.
MODIFIED GRAVITATIONAL THEORIES AND COSMIC ACCELERATION
Authors: EASSON DAMIEN A.
Published: March 2005

Modified gravitational theories can provide alternatives to dark energy as an explaination for the observed late-time cosmic acceleration. Several examples of low-curvature corrections to the Einstein-Hilbert action are studied. These models generically contain unstable de Sitter solutions and, depending on the parameters of the theory, can exhibit late time accelerating attractor solutions.
A FUZZY SUPERSYMMETRIC NON-LINEAR SIGMA MODEL
Authors: KÜRKÇÜOǦLU SEÇKİN
Published: March 2005

We present the ideas leading to the construction of non-linear sigma model on the fuzzy supersphere [Formula: see text]. In a recent article1Bott projectors have been used to obtain the fuzzy [Formula: see text] model. Here we obtain the supersymmetric extensions of these projectors and their fuzzy versions. The latter are then used to construct the non-linear sigma model on [Formula: see text]. We discuss the interpretation of the resulting model as a finite-dimensional matrix model.
STUDY OF LEPTONIC CP VIOLATION
Authors: NASRI S. , SCHECHTER J. , MOUSSA S.
Published: March 2005

The "complementary" Ansatz, Tr (Mν)=0, where Mν is the prediagonal neutrino mass matrix, seems a plausible approximation for capturing in a self contained way some of the content of Grand Unification. We study its consequences in the form of relations between the neutrino masses and CP violation phases.
CP PHASES IN THE LEPTONIC SECTOR OF LRSUSY AND LEPTOGENESIS
Authors: FRANK M.
Published: March 2005

We analyze the effects of the current neutrino data on thermal leptogenesis and lepton flavor violating and conserving processes in a fully left-right extension of the minimal supersymmetric model. The model has several phases from both the heavy and light neutrino sectors: two CKM-type phases, and four Majorana phases, which give new contributions to CP-violating parameters and leptogenesis. We study observable effects of these phases in most general neutrino mixing scenarios, with either hierarchical, inverse hierarchical or quasi-degenerate light and heavy neutrinos. The CP violating phases in both the heavy and light neutrino sectors of the left-right supersymmetric model have unique features which may distinguish the model from other supersymmetric scenarios.
THE BOUNDS ON LORENTZ AND CPT VIOLATING PARAMETERS IN THE HIGGS SECTOR
Authors: TURAN ISMAIL
Published: March 2005

In this talk, I discuss possible bounds on the Lorentz and CPT violating parameters in the Higgs sector of the so called minimal Standard-Model Extension (SME). The main motivation to this study is coming from the fact that unlike the parameters in the fermion and gauge sector, there are no published bounds on the parameters in the Higgs sector. From the one-loop contributions to the photon propagator the bounds on the CPT-even asymmetric coefficients are obtained and the cμν coefficients in the fermion sector determine the bound on the CPT-even symmetric coefficients. The CPT-odd coefficient is bounded from the non-zero vacuum expectation value of the Z-boson.
PROBING THE QUARK AND GLUEBALL ADMIXTURES OF THE SCALAR MESONS
Authors: FARIBORZ A. H.
Published: March 2005

A nonlinear chiral Lagrangian framework for scalar mesons below 2 GeV [the I =l/2 states: κ(900) and [Formula: see text]; the I=1 states: a0(980) and a0(1450); and the I=0 states: α(550), f0(980), f0(1370), f0(1500) and f0(1710)] is presented. This framework is formulated in terms of two meson nonets with a mixing mechanism dictated by SU (3) symmetry and its breakdown.
IS IT POSSIBLE TO CONSTRUCT THE PROTON STRUCTURE FUNCTION BY LORENTZ-BOOSTING THE STATIC QUARK-MODEL WAVE FUNCTION?
Authors: KIM Y. S. , NOZ MARILYN E.
Published: March 2005

The energy-momentum relations for massive and massless particles are E=p2/2m and E=pc respectively. According to Einstein, these two different expressions come from the same formula [Formula: see text]. Quarks and partons are believed to be the same particles, but they have quite different properties. Are they two different manifestations of the same covariant entity as in the case of Einstein's energy-momentum relation? The answer to this question is YES. It is possible to construct harmonic oscillator wave functions which can be Lorentz-boosted. They describe quarks bound together inside hadrons. When they are boosted to an infinite-momentum frame, these wave functions exhibit all the peculiar properties of Feynman's parton picture. This formalism leads to a parton distribution corresponding to the valence quarks, with a good agreement with the experimentally observed distribution.
COSMOLOGY FROM MODULI DYNAMICS
Authors: BISWAS TIRTHABIR , JAIKUMAR PRASHANTH
Published: March 2005

We investigate moduli field dynamics in supergravity/M-theory like set ups where we turn on fluxes along some or all of the extra dimensions. As has been argued in the context of string theory, we observe that the fluxes tend to stabilize the squashing (or shape) modes. Generically we find that at late times the shape is frozen while the radion evolves as a quintessence field. At earlier times we have a phase of radiation domination where both the volume and the shape moduli are slowly evolving. However, depending on the initial conditions and the parameters of the theory, like the value of the fluxes, curvature of the internal manifold and so on, the dynamics of the internal manifold can be richer with interesting cosmological consequences, including inflation.
TACHYON DEFECT FORMATION AND REHEATING IN BRANE-ANTIBRANE INFLATION
Authors: BARNABY NEIL , CLINE JAMES M.
Published: March 2005

We study analytically the dynamical formation of lower dimensional branes at the endpoint of brane-antibrane inflation through the condensation of topological defects of the tachyon field which describes the instability of the initial state. We then use this information to quantify the efficiency of the reheating which is due to the coupling of time dependent tachyon background to massless gauge fields which will be localized on the final state branes. We improve upon previous estimates indicating that this can be an efficient reheating mehcanism for observers on the brane.
NEW PHYSICS SIGNALS THROUGH CP VIOLATION IN B→ρπ
Authors: PAGÉ VÉRONIQUE
Published: March 2005

We describe here a method for detecting physics beyond the standard model via CP violation in B→ρπ decays. Using a Dalitz-plot analysis to obtain α, along with an analytical extraction of the various tree (T) and penguin (P) amplitudes, we obtain a criterion for the absence of new physics (NP). This criterion involves the comparison of the measured |P/T| ratio with its value as predicted by QCD factorization. We show that the detection of NP via this method has a good efficiency when compared with the corresponding technique using B→ππ decays.
CP VIOLATION IN B→πK DECAYS
Authors: IMBEAULT MAXIME
Published: March 2005

I briefly review CP violation in the B system, concentrating on B→πK decays. I discuss how to deal with electroweak-penguin contributions to these decays using flavour SU (3). With these, I show that the entire unitarity triangle can be extracted from measurements of B→πK decays. Finally, I examine the signals for new physics in these decays and the possibilities for measuring them.
INCLUSIVE WEAK RADIATIVE AND SEMILETPTONIC B DECAY
Authors: WISE MARK B.
Published: March 2005

Inclusive weak radiative and semileptonic B decays play a very important role. They are used to determine the weak mixing angles Vcb, and Vub. Furthermore the weak radiative decays provide an important constraint on extensions of the standard model, in particular low energy supersymmetry. I review the theoretical understanding of these processes with particular emphasis on the seminal work of Patrick O'Donnell.
FINITENESS CONDITIONS FOR REWRITING SYSTEMS
Authors: MCGLASHAN STUART , PASKU ELTON , PRIDE STEPHEN J.
Published: March 2005

Monoids that can be presented by a finite complete rewriting system have both finite derivation type and finite homological type. This paper introduces a higher dimensional analogue of each of these invariants, and relates them to homological finiteness conditions.
COMPUTATIONAL PROBLEMS IN HYPERBOLIC GROUPS
Authors: MARSHALL JOSEPH
Published: March 2005

We describe an algorithm due to Eric Swenson for testing quasi-convex subgroups of hyperbolic groups for near malnormality. We go on to discuss some strategies for the practical implementation of this algorithm and consider an example. We then show that the methods of Swenson's algorithm extend to give practical solutions to the conjugacy problem for infinite order elements, and to the normalizer and centralizer problems for subgroups satisfying appropriate conditions. The results are presented here in outline — all the algorithms are described in more detail in the author's PhD thesis (University of Warwick, 2001).
SUBSEMIGROUPS OF THE BICYCLIC MONOID
Authors: DESCALÇO L. , RUŠKUC N.
Published: March 2005

In this paper we give a description of all subsemigroups of the bicyclic monoid B. We show that there are essentially five different types of subsemigroups. One of them is the degenerate case, and the remaining four split in two groups of two, linked by the obvious anti-isomorphism of B. Each subsemigroup is characterized by a certain collection of parameters. Using our description, we determine the regular, simple and bisimple subsemigroups of B. Finally we describe algorithms for obtaining the parameters from the generating set.
RESIDUAL FINITENESS OF OUTER AUTOMORPHISM GROUPS OF FINITELY GENERATED NON-TRIANGLE FUCHSIAN GROUPS
Authors: ALLENBY R. B. J. T. , KIM GOANSU , TANG C. Y.
Published: March 2005

In [5] Grossman showed that outer automorphism groups of free groups and of fundamental groups of compact orientable surfaces are residually finite. In this paper we introduce the concept of "Property E" of groups and show that certain generalized free products and HNN extensions have this property. We deduce that the outer automorphism groups of finitely generated non-triangle Fuchsian groups are residually finite.
A UNIQUE DECOMPOSITION THEOREM FOR FACTORIAL LANGUAGES
Authors: AVGUSTINOVICH S. V. , FRID A. E.
Published: March 2005

We study decompositions of a factorial language to catenations of factorial languages and introduce the notion of a canonical decomposition. Then we prove that for each factorial language, a canonical decomposition exists and is unique.
A CHARACTERIZATION OF SCHMIDT GROUPS BY THEIR ENDOMORPHISM SEMIGROUPS
Authors: PUUSEMP PEETER
Published: March 2005

A Schmidt group is a non-nilpotent finite group in which each proper subgroup is nilpotent. Each Schmidt group G is a solvable group of order ps qv (where p and q are different primes) with a unique Sylow p-subgroup P and a cyclic Sylow q-subgroup Q, and hence G is a semidirect product of P by Q. Denote by [Formula: see text] the class of all Schmidt groups of orders ps qv, where p, q, and v are fixed and s is arbitrary. It is shown in this paper that the class [Formula: see text] can be characterized by the properties of the endomorphism semigroups of the groups of this class. It follows from this characterization that if [Formula: see text] and H is another group such that the endomorphism semigroups of G and H are isomorphic, then [Formula: see text], too.
ON COMMUTATOR LENGTH OF CERTAIN CLASSES OF SOLVABLE GROUPS
Authors: AKHAVAN-MALAYERI MEHRI
Published: March 2005

Let G be a group and G′ be its commutator subgroup. Denote by c(G) the minimal number such that every element of G′ can be expressed as a product of at most c(G) commutators. We find suitable bounds for c(G) when G is a free nilpotent by abelian group. Then we prove that c(G) is finite if G is a n-generator solvable group. And G has a nilpotent by abelian normal subgroup K of finite index. Moreover we have c(G) ≤ s(s + 1)/2 + 72n2 + 47n, where s is the number of generators of K. We also prove that in a solvable group of finite Pruffer rank s every element of its commutator subgroup is equal to a product of at most s(s + 1)/2 + 72s2 + 47s. And finally as a corollary of the above results we show that if A is a normal subgroup of a solvable group G such that G/A is a d-generator finite group. And A has finite Pruffer rank s. Then c(G) ≤ s(s + 1)/2 + 72(s2 + n2) + 47(s + n). The bounds we find are independent of the solvability length of the groups.
MINIMAL FORBIDDEN PATTERNS OF MULTI-DIMENSIONAL SHIFTS
Authors: BÉAL MARIE-PIERRE , FIORENZI FRANCESCA , MIGNOSI FILIPPO
Published: March 2005

We study whether the entropy (or growth rate) of minimal forbidden patterns of symbolic dynamical shifts of dimension 2 or more, is a conjugacy invariant. We prove that the entropy of minimal forbidden patterns is a conjugacy invariant for uniformly semi-strongly irreducible shifts. We prove a weaker invariant in the general case.
MOVING BANDS AND MOVING BOUNDARIES WITH DECREASING SPEED IN POLYMER CRYSTALLIZATION
Authors: ESCOBEDO RAMÓN , CAPASSO VINCENZO
Published: March 2005

A deterministic model of polymer crystallization, derived from a previous stochastic one, is considered. The model describes the crystallization process of a rectangular sample of a material cooled at one of its sides. It is a reaction–diffusion system, composed of a PDE for the temperature and an ODE for the phase change of a polymer melt from liquid to crystal. The two equations are strongly coupled since the evolution of temperature depends on a source term, due to the latent heat developed during the phase change, the nucleation and growth rates are functions of the local (in time and space) temperature. The main difference with respect to the previous model is the introduction of a critical temperature of freezing in these functions. The paper does not contain detailed analytical aspects, that are left to subsequent investigations. A qualitative analysis of the proposed model is carried out, based on numerical simulations. An interesting feature shown by the simulations is that the solution exhibits an advancing moving band of crystallization in the mass distribution, as well as a moving boundary in the temperature field, both advancing with the same decreasing velocity. For some values of the parameters, which are typical of the physical problem, the advance takes place by jumps due to regular stops of the most advanced point of crystallization. The duration of these halts increases as the applied temperature decreases. This may indicate that the crystallization time is not a monotone function of the applied temperature. A simplified mathematical model is eventually proposed which reproduces the same patterns.
NEW MODELS IN MICROPOLAR FLUID AND THEIR APPLICATION TO LUBRICATION
Authors: BAYADA GUY , BENHABOUCHA NADIA , CHAMBAT MICHÈLE
Published: March 2005

A thin micropolar fluid with new boundary conditions at the fluid-solid interface, linking the velocity and the microrotation by introducing a so-called "boundary viscosity" is presented. The existence and uniqueness of the solution is proved and, by way of asymptotic analysis, a generalized micropolar Reynolds equation is derived. Numerical results show the influence of the new boundary conditions for the load and the friction coefficient. Comparisons are made with other works retaining a no slip boundary condition.
MODELING HETEROGENEOUS MARTENSITIC WIRES
Authors: LE DRET HERVÉ , MEUNIER NICOLAS
Published: March 2005

We give a direct derivation of a theory of martensitic heterogeneous wires in the zero thickness and homogenization limit via a convergence result. We start from three-dimensional nonlinear hyperelasticity theory augmented by a term of interfacial energy of the van der Waals type. The derivation involves no a priori choice of asymptotic expansion or Ansatz. It yields a wire theory with two Cosserat vector fields. A formal derivation is given of higher theories for homogeneous wires, which yields one corrector for the deformation of the central line and two correctors for the Cosserat vector fields. Finally, we present a few numerical results.
AN OPTIMALITY CONDITION FOR THE ASSEMBLY DISTRIBUTION IN A NUCLEAR REACTOR
Authors: THEVENOT LAURENT
Published: March 2005

This paper presents an optimality condition for the optimization problem of the assembly distribution in a nuclear reactor, by using the homogenization method. In this paper the reactivity of the reactor core is measured by the critical eigenvalue for both continuous and multigroup neutron transport models. In particular, we extend the spectral theory of the critical eigenvalue and prove the differentiability of the latter with respect to the design parameter, the configuration of the fuels.
COMPUTATIONAL MODELING OF DYNAMICAL SYSTEMS
Authors: JANSSON JOHAN , JOHNSON CLAES , LOGG ANDERS
Published: March 2005

In this short note, we discuss the basic approach to computational modeling of dynamical systems. If a dynamical system contains multiple time scales, ranging from very fast to slow, computational solution of the dynamical system can be very costly. By resolving the fast time scales in a short time simulation, a model for the effect of the small time scale variation on large time scales can be determined, making solution possible on a long time interval. This process of computational modeling can be completely automated. Two examples are presented, including a simple model problem oscillating at a time scale of 10–9 computed over the time interval [0,100], and a lattice consisting of large and small point masses.
Shanghai's Development as an International Financial Center
Authors: Laurenceson James , Tang Kam Ki
Published: March 2005

In 1949 Shanghai was the leading international financial center (IFC) in Asia. Recently the push of Shanghai to regain its long lost status of a regional IFC has begun to attract widespread interest. This paper first draws upon the IFC literature to highlight the factors that are considered to be important in determining the potential of a city to emerge as an IFC. Shanghai's progress is then measured against these criteria and is also placed in a comparative perspective by measuring against Hong Kong and Singapore.
Stock Repurchase in Korea: Market Reactions and Operating Performance
Authors: Park Youngkyu , Jung Kooyul
Published: March 2005

This study examines the motive for stock repurchase. We examine four hypotheses — undervaluation, signaling, free cash flow, and optimal leverage hypotheses — using both short-run and long-run market reactions. We find that the undervaluation hypothesis is most consistent with both short-run and long-run tests. Improvement in operating performance following repurchase suggests the signaling hypothesis. However, the signaling hypothesis is supported only in the long-run test, not the short-run test, suggesting that market underreaction exists to the signaling initially. Of the control variables, the target purchase ratio and ownership by the largest shareholders are found significant, suggesting that the magnitude of repurchase and the ownership increase motive by the largest shareholders are also important factors that explain the repurchase.
Estimating and Explaining Extreme Comovements in Asia-Pacific Equity Markets
Authors: Chandra Mahendra
Published: March 2005

The correlation structure amongst selected Asia-Pacific equity markets is examined using the Constant Correlation multivariate GARCH (CC-MGARCH) model, the Dynamic Conditional Correlation multivariate GARCH (DCC-MGARCH) model, and an Exponentially-Weighted Moving Average (EWMA) correlation measure. The markets of Australia, Hong Kong, Japan and Singapore are analyzed from 1990 to 2001 and dynamic nature of the correlation is captured and explained. We find that global as well as regional factors contribute to the correlation spikes. Extreme volatility does not necessarily result in extreme correlations between some markets and there is higher comovement between markets since the Asian financial crisis. We also find that despite common periods of high volatility, there is still economic justification for diversification within this region.