bluuebunny/crossref_metadata_2025 huggingface dataset:
FIELD STRENGTH FORMULATION OF SU(2) YANG–MILLS THEORY IN THE MAXIMAL ABELIAN GAUGE: PERTURBATION THEORY
Authors: QUANDT M. , REINHARDT H.
Published: September 2003

We present a reformulation of SU(2) Yang–Mills theory in the maximal Abelian gauge, where the non-Abelian gauge field components are exactly integrated out at the expense of a new Abelian tensor field. The latter can be treated in a semiclassical approximation and the corresponding saddle point equation is derived. Besides the nontrivial solutions, which are presumably related to nonperturbative interactions for the Abelian gauge field, the equation of motion for the tensor fields allows for a trivial solution as well. We show that the semiclassical expansion around this trivial solution is equivalent to the standard perturbation theory. In particular, we calculate the one-loop β-function for the running coupling constant in this approach and reproduce the standard result.
THIRD QUANTIZATION OF KALUZA–KLEIN COSMOLOGY AND COMPACTIFICATION
Authors: OHKUWA YOSHIAKI
Published: September 2003

We study on the third quantization of a Kaluza–Klein toy model. In this model time (x) is defined by the scale factor of universe, and the space coordinate (y) is defined by the ratio of the scales of the ordinary space and the internal space. We calculate the number density of the universes created from nothing and examine whether the compactification can be explained statistically by the idea of the third quantization.
MODIFIED LAPLACE TRANSFORMATION METHOD AT FINITE TEMPERATURE: APPLICATION TO INFRARED PROBLEMS OF N COMPONENT ϕ4 THEORY
Authors: YAMADA H.
Published: September 2003

The modified Laplace transformation method is applied to N component ϕ4 theory and the finite temperature problem in the massless limit is re-examined in the large N limit. We perform perturbation expansion of the dressed thermal mass in the massive case to several orders and try the massless approximation with the help of modified Laplace transformation. The contribution with fractional power of the coupling constant is recovered from the truncated massive series. The use of inverse Laplace transformation with respect to the mass square is crucial in evaluating the coefficients of fractional power terms.
A NOETHER SYMMETRY STUDY IN SCALAR-TENSOR THEORY
Authors: MODAK B. , KAMILYA S. , BISWAS S.
Published: September 2003

In this work we study a general scalar-tensor theory in which the coupling and potential functions are determined from Noether symmetry arguments. We also obtain exact solutions of the field equations and found that the universe asymptotically follows an exponential expansion having no graceful exit. The study of the functional form of ω(φ) reveals that the theory asymptotically becomes an attractor of general relativity. We restrict ourselves to spatially homogeneous, isotropic flat universe.
QUANTUM MECHANICS OVER A q-DEFORMED (0 + 1)-DIMENSIONAL SUPERSPACE
Authors: MONTANI H. , TRINCHERO R.
Published: September 2003

We built up an explicit realization of (0 + 1)-dimensional q-deformed superspace coordinates as operators on standard superspace. A q-generalization of supersymmetric transformations is obtained, enabling us to introduce scalar superfields and a q-supersymmetric action. We consider a functional integral based on this action. Integration is implemented, at the level of the coordinates and at the level of the fields, as traces over the corresponding representation spaces. Evaluation of these traces leads us to standard functional integrals. The generation of a mass term for the fermion field leads, at this level, to an explicitly broken version of supersymmetric quantum mechanics.
LAGRANGIAN APPROACH TO LOCAL SYMMETRIES AND SELF-DUAL MODEL IN GAUGE INVARIANT FORMULATION
Authors: KIM YONG-WAN , ROTHE KLAUS D.
Published: September 2003

Taking the Stückelberg Lagrangian associated with the Abelian self-dual model of P. K. Townsend et al. as a starting point, we embed this mixed first- and second-class system into a pure first-class system by following systematically the generalized Hamiltonian approach of Batalin, Fradkin and Tyutin. The resulting Lagrangian possesses an extended gauge invariance and provides a nontrivial example for a general Lagrangian approach to unravelling the full set of local symmetries of a Lagrangian.
SEMILEPTONIC DECAYS, MAGNETIC MOMENTS AND SPIN DISTRIBUTIONS OF SPIN-1/2 BARYONS WITH SEA CONTRIBUTION
Authors: GUPTA V. , HUERTA R. , SÁNCHEZ-COLÓN G.
Published: September 2003

Spin-1/2 baryons are considered as a composite system made out of a "core" of three-quarks surrounded by a "sea" (of gluons and [Formula: see text]-pairs) which is specified by its total quantum numbers. Specifically, we assume this sea to be a flavor octet with spin-0 or 1 but no color. We show our model can provide very good fits to magnetic moments and semileptonic decay data using experimental errors. The predictions for spin distributions are in reasonable agreement with experiment.
CONSTRAINT ON THE COSMOLOGICAL CONSTANT FROM GRAVITATIONAL LENSING IN AN EVOLUTIONARY MODEL OF GALAXIES
Authors: JAIN DEEPAK , PANCHAPAKESAN N. , MAHAJAN S. , BHATIA V. B.
Published: September 2003

We study the effect of the cosmological constant on the statistical properties of gravitational lenses in flat cosmologies (Ω0+λ0=1). It is shown that some of the lens observables are strongly affected by the cosmological constant, especially in a low-density universe, and its existence might be inferred by a statistical study of the lenses. In particular, the optical depth of the lens distribution may be used best for this purpose without depending much on the lens model. We calculate the optical depth (probability of a beam encountering a lens event) for a source in a new picture of galaxy evolution based on number evolution in addition to pure luminosity evolution. It seem that present-day galaxies result from the merging of a large number of building blocks. We have tried to put a limit on the cosmological constant in this new picture of galaxy evolution. This evolutionary model of galaxies permits a larger value of the cosmological constant.
THE EXPULSION OF CHROMOMAGNETIC FIELDS
Authors: ABOUELSAOOD AHMED
Published: September 2003

The time evolution of a classical gauge field configuration of the form of a uniform chromomagnetic field plus an added perturbation propotional to the unstable zero mode in the uniform background is studied numerically by means of the classical lattice field equations. It turns out that the decay process has two distinct stages. In the first stage, the unstable mode grows with time exponentially, as expected from the linearized equations of motion. This stage comes to an end when the magnetic field in the perturbation region reaches zero and reverses direction, making the unstable zero mode stable and vice versa. The second phase is characterized by the oscillation of the magnetic field around the zero value in the region of the initial perturbation and its gradual expulsion from the surrounding region, with the boundaries between the low field region and the high field region moving out at the speed of light. The energy of the vanished magnetic field is converted into the energy of the electric field induced according to Faraday's law.
SOME ADVANTAGES OF SUSY SU(4)×SU(2)L×SU(2)R MODEL IN STRING INSPIRED SO(10) GUT'S
Authors: MURAYAMA AKIHIRO
Published: September 2003

A D-parity violated SUSY SU (4)× SU (2)L× SU (2)R gauge model with the Higgs sector [Formula: see text] + some (1, 1, 1)'s is shown to have the following advantages: (i) It is a very simple solution that satisfies MX=M string ≈0.5 × 1018 GeV and M INT ≈ 5 × 1011 GeV in superstring inspired SO(10) GUT's. (ii) The proton is stable by the automatic "doublet–triplet splitting" closely connected with the D-parity violation. (iii) The minimization of SUSY one-loop effective potential in a toy model suggests that the SO(10) gauge theory tends to break dynamically down to the SU (4)× SU (2)L× SU (2)R model.
FERMI DERIVATIVE AND FERMI–WALKER TRANSPORTS OVER $(\bar{L}_n, g)$-SPACES
Authors: MANOFF S.
Published: September 2003

The notions of Fermi covariant differential operator, Fermi derivative, and Fermi–Walker transport are generalized for the case of differentiable manifolds with different (not only by sign) contravariant and covariant affine connections and metrics [[Formula: see text]-spaces]. The generalization of Fermi–Walker transport is not unique and depends on the structure of the covariant antisymmetric tensor of second rank in the construction of the Fermi–Walker transport. The existence of such type of transport over [Formula: see text]-spaces allows the determination of a proper nonrotating accelerated observer's frame of reference, if a [Formula: see text]-space is used as a model of the space–time.
NONFACTORIZABLE LONG DISTANCE CONTRIBUTIONS IN COLOR SUPPRESSED DECAYS OF B MESONS
Authors: TERASAKI K.
Published: September 2003

[Formula: see text], D*π, [Formula: see text] and J/ψπ decays are studied. Their amplitude is given by a sum of factorized and nonfactorizable ones. The latter which is estimated by using a hard pion approximation is rather small in color favored [Formula: see text] and D*π decays but still can efficiently interfere with the main amplitude given by the factorization. In the color suppressed [Formula: see text] and J/ψπ decays, the nonfactorizable contribution is very important. The sum of the factorized and nonfactorizable amplitudes can reproduce well the existing experimental data on the branching ratios for the color favored [Formula: see text] and D*π and the color suppressed [Formula: see text] and J/ψπ decays by taking reasonable values of unknown parameters involved.
NEW SPIN-2 GAUGED SIGMA MODELS AND GENERAL CONFORMAL FIELD THEORY
Authors: DE BOER J. , HALPERN M. B.
Published: September 2003

Recently, we have studied the general Virasoro construction at one loop in the background of the general nonlinear sigma model. Here, we find the action formulation of these new conformal field theories when the background sigma model is itself conformal. In this case, the new conformal field theories are described by a large class of new spin-2 gauged sigma models. As examples of the new actions, we discuss the spin-2 gauged WZW actions, which describe the conformal field theories of the generic affine-Virasoro construction, and the spin-2 gauged g/h coset constructions. We are able to identify the latter as the actions of the local Lie h-invariant conformal field theories, a large class of generically irrational conformal field theories with a local gauge symmetry.
SOME ASPECTS OF GEOMETRICAL CONFINEMENT
Authors: NOVELLO M. , DE LORENCI V. A. , ELBAZ E.
Published: September 2003

In this paper we present a toy model for the dynamics of a gauge field theory in such a way that spin-one particles can be confined in a compact domain. We show that the property of confinement can be associated to the formation of a null surface identified to a horizon. This is due to the presence of an effective geometry generated by the self-interaction of the gauge field that guides the wave propagation of the field.

This phenomenon has a striking analogy to the gravitational black hole in Einstein's general theory of relativity, separating two domains of space–time that can be trespassed only into one direction.
SUPEREMBEDDINGS, NONLINEAR SUPERSYMMETRY AND FIVE-BRANES
Authors: ADAWI TOM , CEDERWALL MARTIN , GRAN ULF , HOLM MAGNUS , NILSSON BENGT E. W.
Published: September 2003

We examine general properties of superembeddings, i.e. embeddings of supermanifolds into supermanifolds. The connection between an embedding procedure and the method of nonlinearly realized supersymmetry is clarified, and we demonstrate how the latter arises as a special case of the former. As an illustration, the super-5-brane in seven dimensions, containing a self-dual three-form world volume field strength, is formulated in both languages, and provides an example of a model where the embedding condition does not suffice to put the theory on-shell.
METHOD OF SOLVING CONFORMAL MODELS IN D-DIMENSIONAL SPACE II A FAMILY OF EXACTLY SOLVABLE MODELS IN D>2
Authors: FRADKIN E. S. , YA. PALCHIK M.
Published: September 2003

We study a family of exactly solvable models of conformally invariant quantum field theory in D-dimensional space. We demonstrate the existence of D-dimensional analogs of primary and secondary fields. Under the action of the energy–momentum tensor and conserved currents, the primary field creates an infinite set of (tensor) secondary fields of different generations. The commutators of secondary fields with zero components of the current and energy–momentum tensor include anomalous operator terms.

We show that the Hilbert space of conformal theory has a special sector whose structure is solely defined by the Ward identities independently of the choice of dynamical model. The states of this sector are constructed from secondary fields. Definite self-consistent conditions on the states of the latter sector fix the choice of the field model uniquely. The above self-consistent conditions are formulated as follows. Special superpositions Qs, s= 1, 2, …, of secondary fields are constructed. Each superposition is determined by the requirement that the form of its commutators with energy–momentum tensor of a primary fiel d. Each equation Qs(x)=0 is consistent, and defines an exactly solvable model for D ≥ 3. The structure of these models is analogous to that of well-known two-dimensional conformal models. The states Qs(x)|0> are analogous to the null vectors of two-dimensional theory. In each of these models one can obtain a closed set of differential equations for all the higher Green functions, as well as algebraic equations relating the scale dimension of the fundamental field to the D-dimensional analog of a central charge. As an example, we present a detailed discussion on a pair of exactly solvable models in even-dimensional space D≥4.
METHOD OF SOLVING CONFORMAL MODELS IN D-DIMENSIONAL SPACE III SECONDARY FIELDS IN D>2 AND THE SOLUTION OF TWO-DIMENSIONAL MODELS
Authors: FRADKIN E. S. , YA. PALCHIK M.
Published: September 2003

We proceed with the study (started in Refs. 1 and 2) of the Hilbert space of conformal field theory in D di mensions. We discuss an infinite family of secondary fields [Formula: see text] generated by the action of the components of energy–momentum tensor Tμν on the fundamental (primary) field. It is shown that the states of these fields form a specific sector of the Hilbert space H which is determined by the Ward identities and [Formula: see text]-dimensional conformal symmetry. We demonstrate that for D = 2 the subspace H coincides with the space of representation of the Virasoro algebra. Each exactly solvable model in the case of D ≥ 2 is defined by the requirement of vanishing of a certain state Qs(x)|0> ⊂ H analogous to the null vector of two-dimensional theory. The Green functions of the fields [Formula: see text] are calculated in terms of the Green functions of the fundamental field. It is shown that all the Green functions of the type [Formula: see text] satisfy the anomalous Ward identities. The anomalous contributions are given by the fields [Formula: see text], where s′≤s-1. The fields Qs are constructed as superpositions of secondary fields with the anomalous contribution equal to zero,

An approach developed is based on a finite-dimensional conformal symmetry for any D ≥ 2. Nevertheless the resulting models have the structure analogous to that of two-dimensional conformal theories. This analogy is discussed in detail. It is shown that for D = 2 the family of models coincides with the well-known family of conformal models based on infinite-dimensional conformal symmetry. The analysis of this phenomenon indicates the existence of the D-dimensional analog of the Virasoro algebra.
RELATED OPERATORS AND EXACT SOLUTIONS OF SCHRÖDINGER EQUATIONS
Authors: CARIÑENA J. F. , MARMO G. , PERELOMOV A. M. , RAÑADA M. F.
Published: September 2003

We consider the Schrödinger equation just as a differential equation, disregarding the physical interpretation associated with solutions. By introducing the notion of A-related equations, A being a differential operator, we associate with it a Riccati equation and study the solutions when the potential is a meromorphic function.
A STUDY OF KANTOWSKI–SACHS MODEL IN ASHTEKAR VARIABLES
Authors: CHAKRABORTY SUBENOY , CHAKRAVARTY NABAJIT
Published: September 2003

In this paper we study classical and quantum cosmology in Kantowski–Sachs model using Ashtekar variables. Classical solutions are obtained for the above model with a cosmological term and Hamilton–Jacobi (HJ) equations have been studied to obtain inflationary solutions. In quantum cosmology, the wave function of the Universe is obtained using path integral formalism as well as by solving the Wheeler–DeWitt (WD) equation.
ON TIME DEFINITION AND THE SCHRÖDINGER'S CAT PARADOX
Authors: SYROS C. , SCHULZ-MIRBACH C.
Published: September 2003

The conventional tacit assumption according to which quantum processes take place in the Newtonian time topology is abandoned. The chronotopological space is based on the interaction proper time neighborhood. It is disconnected, satisfies the separation axioms of the topological space [Formula: see text], and is developed and used to solve some problems related to quantum field theory. In chronotopology the time evolution operator, [Formula: see text], breaks down into the alternative [Formula: see text] = either [Formula: see text]. The unitary, U, and the reduction, R, dynamics are implemented by means of two time evolution operators, [Formula: see text] and [Formula: see text], derived from a quantized version of Gel'fand's theory of the generalized random and infinitely divisible fields. As an application the solution of the paradox of Schrödinger's cat is presented.
A BURGE TREE OF VIRASORO-TYPE POLYNOMIAL IDENTITIES
Authors: FODA OMAR , LEE KEITH S. M. , WELSH TREVOR A.
Published: September 2003

Using a summation formula due to Burge, and a combinatorial identity between partition pairs, we obtain an infinite tree of q-polynomial identities for the Virasoro characters [Formula: see text], dependent on two finite size parameters M and N, in the cases where:

(1) p and p′ are coprime integers that satisfy 0 < p < p′.

(2) If the pair (p′:p) has a continued fraction (c1, c2, …, ct-1, ct+2), where t≥1, then the pair (s:r) has a continued fraction (c1, c2, …, cu-1, d), where 1 ≤ u ≤ t, and 1 ≤ d ≤ cu.

The limit M → ∞, for fixed N, and the limit N → ∞, for fixed M, lead to two independent boson-fermion-type q-polynomial identities: in one case, the bosonic side has a conventional dependence on the parameters that characterize the corresponding character. In the other, that dependence is not conventional. In each case, the fermionic side can also be cast in either of two different forms.

Taking the remaining finite size parameter to infinity in either of the above identities, so that M → ∞ and N → ∞, leads to the same q-series identity for the corresponding character.
FOUR-LEPTON SIGNALS FROM SUPERSYMMETRY AT CMS
Authors: ABDULLIN S. , ANTUNOVIĆ Ž. , DŽELALIJA M.
Published: September 2003

We investigate the possibility of searching for squarks and gluinos in the [Formula: see text] + jets final states within the SUGRA framework. With the chosen set of model parameters, A0= 0, tan β=2, and with μ both negative and positive, for an integrated luminosity of 10 fb-1 the CMS detector would probe squarks and a gluino mass range of up to ≈ 1 TeV.
TOP QUARK PHYSICS AT THE TEVATRON
Authors: BHAT PUSHPALATHA C. , PROSPER HARRISON B. , SNYDER SCOTT S.
Published: September 2003

The discovery of the top quark in 1995, by the CDF and DØ collaborations at the Fermilab Tevatron, marked the dawn of a new era in particle physics. Since then, enormous efforts have been made to study the properties of this remarkable particle, especially its mass and production cross section. In this article, we review the status of top quark physics as studied by the two collaborations using the [Formula: see text] collider data at [Formula: see text] TeV. The combined measurement of the top quark mass, mt=173.8±5.0 GeV /c2, makes it known to a fractional precision better than any other quark mass. The production cross sections are measured as [Formula: see text] pb by CDF and [Formula: see text] pb by DØ. Further investigations of [Formula: see text] decays and future prospects are briefly discussed.
DYON–DYON BOUND STATES IN NON-RELATIVISTIC AND RELATIVISTIC FRAMEWORKS
Authors: RAJPUT B. S. , PANDEY V. P.
Published: September 2003

Investigating dyon–dyon bound states in non-relativistic as well as in relativistic frameworks, it has been shown that in this system a dyon moves on a cone with its apex at the other dyon and axis along its angular momentum. Dyon–dyon bound states have been investigated in a non-relativistic framework to obtain energy eigenvalue and energy eigenfunction. It has also been shown that the exact solution of Dirac equation for this system is not possible due to the presence of a term vanishing more rapidly than r-1 in the potential of the system.
THE TOROID DIPOLE MOMENT OF THE NEUTRINO
Authors: DUBOVIK VLADIMIR M. , KUZNETSOV VALENTIN E.
Published: September 2003

We discuss the third electromagnetic characteristic of the neutrino, i.e. the toroid dipole moment (TDM), in the framework of the Standard Model. The TDM's distinctions from and similarities to an anapole moment are mentioned. The calculations of toroid dipole moments of νe,μ,τ neutrinos have been done by the dispersion method in the one-loop approximation of the SM for the Majorana case and generalized to the Dirac one. We found them to be different from zero in the case of massive as well as massless neutrinos. The behavior of the νe,μ,τ toroid form factors is also presented in the [Formula: see text] range. All external particles are on the mass shell and there are no problems with the physical interpretation of the final result. Some manifestations of the electromagnetic interactions of neutrinos, induced by their toroid moments, are also remarked on.
ONE-LOOP EFFECTS IN VARIOUS DIMENSIONS AND D-BRANES
Authors: BOULAHOUACHE CHAOUKI , THOMPSON GEORGE
Published: September 2003

We calculate some one-loop corrections to the effective action of theories in d dimensions that arise on the dimensional reduction of a Weyl fermion in D dimensions. The terms that we are interested in are of a topological nature. Special attention is given to the effective actions of the super Yang–Mills theories that arise on dimensional reduction of the N=1 theory in six dimensions or on the dimensional reduction of the N=1 theory in ten dimensions. In the latter case we suggest an interpretation of the quantum effect as a coupling of the gauge field on the brane to a relative background gauge field.
QUANTUM CHRONOTOPOLOGY AND TIME ASYMMETRY IN FIELD THEORY
Authors: SYROS C.
Published: September 2003

A new, physical definition of the time elements is mathematically given. Their union constitutes a disconnected time topological space, [Formula: see text]. Based on the properties of this time–space and using the theory of random quantum fields previously developed, a nonunitary evolution operator, [Formula: see text], is derived. [Formula: see text] breaks down into two disjunct, spontaneously renormalized evolution operators by quantizing the random field action integral: one operator is unitary, [Formula: see text], and the other non-measure-preserving, [Formula: see text]. [Formula: see text] coincides, apart from the renormalization, with the evolution operator of the standard QFT. U ump (τ) breaks time symmetry in QFT. It reconciles the time reversal invariance of the basic equations of quantum theory with the irreversibility of the macroscopic, and some microscopic, phenomena. It provides a basis for the CP violation in the neutral K0 meson decay. Functional integrals arising in the theory have in the limit countably additive measures.
EXACT CANONICALLY CONJUGATE MOMENTA APPROACH TO AN SU(N) QUANTUM SYSTEM
Authors: NISHIYAMA SEIYA
Published: September 2003

The collective field formalism by Jevicki and Sakita is a useful approach to the problem of treating general planar diagrams involved in an SU (N) symmetric quantum system. To approach this problem, standing on the Tomonaga spirit we also previously developed a collective description of an SU (N) symmetric Hamiltonian. However, this description has the following difficulties: (i) Collective momenta associated with the time derivatives of collective variables are not exact canonically conjugate to the collective variables; (ii) The collective momenta are not independent of each other. We propose exact canonically conjugate momenta to the collective variables with the aid of the integral equation method developed by Sunakawa et al. A set of exact canonical variables which are derived by the first quantized language is regarded as a natural extension of the Sunakawa et al.'s to the case for the SU (N) symmetric quantum system. A collective Hamiltonian is represented in terms of the exact canonical variables up to the order of [Formula: see text].
THE STATE OF THE COLD DARK MATTER MODELS ON GALACTIC AND SUBGALACTIC SCALES
Authors: TASITSIOMI ARGYRO
Published: September 2003

The Lambda-Cold Dark Matter (ΛCDM) model describes successfully our Universe on large scales, as has been verified by a wide range of observations. A number of apparent inconsistencies have arisen between observations and ΛCDM predictions on small scales. In this work, the current status of observations on galactic and subgalactic scales is reviewed. Theoretical predictions and recent observations are brought together in order to reveal the nature and severity of the inconsistencies. Lastly, the progress towards the resolution of each one of these conflicts is briefly reviewed.
MATCHING OF THE CONTINUOUS GRAVITATIONAL WAVE IN AN ALL SKY SEARCH
Authors: SAHAY S. K.
Published: September 2003

We investigate the matching of continuous gravitational wave (CGW) signals in an all sky search with reference to Earth based laser interferometric detectors. We consider the source location as the parameters of the signal manifold and templates corresponding to different source locations. It has been found that the matching of signals from locations in the sky that differ in their co-latitude and longitude by π radians decreases with source frequency. We have also made an analysis with the other parameters affecting the symmetries. We observe that it may not be relevant to take care of the symmetries in the sky locations for the search of CGW from the output of LIGO-I, GEO600 and TAMA detectors.
QUANTUM ORIGIN OF A HOT UNIVERSE
Authors: DYMNIKOVA IRINA , FIL'CHENKOV MICHAEL
Published: September 2003

We present the results on the quantum birth of a hot FRW universe in de Sitter vacuum from a quantum fluctuation which contains radiation and strings or some quintessence with the equation of state p=-ε/3. The presence of radiation results in quantum tunnelling from a discrete energy level with a non-zero quantized temperature. Energy levels have non-zero width corresponding to temperature fluctuations. The observational constraint on the CMB anisotropy selects the admissible range of the model parameters. For the GUT scale initial de Sitter vacuum, the lower limit on temperature at the start of classical evolution is close to the values predicted by theories of reheating, while an upper limit is far from the threshold for a monopole rest mass. The probability of quantum birth from a level of non-zero energy is much bigger than the probability of quantum birth from nothing. The presence of material with p=-ε/3 mimics a positive curvature term which makes possible quantum tunnelling for an open and a flat universe. Most plausible case is a flat universe arising from an initial fluctuation with a small admixture of radiation and strings with the negative deficit angle.
PROPERTIES OF HOT NEUTRON STAR
Authors: DAS C. , PANDA P. K. , ADHIKARY M.
Published: September 2003

The properties of neutron star at temperatures 5 MeV, 10 MeV and 15 MeV are calculated by solving Tolmann–Oppenheimer–Volkoff (TOV) equation. The required equation of state of pure neutron matter is obtained using density dependent Sussex interaction. It is observed that maximum stable mass of the star corresponds to minimum gravitational radius for a given equation of state. Just like the limiting mass, limiting value of redshift, moment of inertia, Kepler frequency as well as Kepler period are observed in case of the neutron star. It is found that the star become somewhat 'massive' and 'fat' at higher temperatures. With the increase in temperature the moment of inertia and Kepler rotational period increase but redshift decreases and Kepler frequency slows down. We also predict that there is a possibility of pion condensation in pure neutron matter.
SPONTANEOUS VIOLATION OF LORENTZ INVARIANCE AND ULTRA-HIGH ENERGY COSMIC RAYS
Authors: MOFFAT J. W.
Published: September 2003

We propose that local Lorentz invariance is spontaneously violated at high energies, due to a nonvanishing vacuum expectation value of a vector field ϕμ, as a possible explanation of the observation of ultra-high energy cosmic rays with an energy above the GZK cutoff. Certain consequences of spontaneous breaking of Lorentz invariance in cosmology are discussed.
KINEMATICAL SOLUTION OF THE UHE-COSMIC-RAY PUZZLE WITHOUT A PREFERRED CLASS OF INERTIAL OBSERVERS
Authors: AMELINO-CAMELIA GIOVANNI
Published: September 2003

Among the possible explanations for the puzzling observations of cosmic rays above the GZK cutoff there is growing interest in the ones that represent kinematical solutions, based either on general formulations of particle physics with small violations of Lorentz symmetry or on a quantum-gravity-motivated scheme for the breakdown of Lorentz symmetry. An unappealing aspect of these cosmic-ray-puzzle solutions is that they require the existence of a preferred class of inertial observers. Here I propose a new kinematical solution of the cosmic-ray puzzle, which does not require the existence of a preferred class of inertial observers. My proposal is a new example of a type of relativistic theories, the so-called "doubly-special-relativity" theories, which have already been studied extensively over the last two years. The core ingredient of the proposal is a deformation of Lorentz transformations in which also the Planck scale Ep (in addition to the speed-of-light scale c) is described as an invariant. Just like the introduction of the invariant c requires a deformation of the Galileian transformations into the Lorentz transformations, the introduction of the invariant Ep requires a deformation of the Lorentz transformations, but there is no special class of inertial observers. The Pierre Auger Observatory and the GLAST space telescope should play a key role in future developments of these investigations. I also emphasize that the doubly-special-relativity theory here proposed, besides providing a solution for the cosmic-ray puzzle, is also the first doubly-special-relativity theory with a natural description of macroscopic bodies, and may find applications in the context of a recently-proposed dark-energy scenario.
GRAVITATIONAL COLLAPSE OF SPHERICALLY SYMMETRIC ANISOTROPIC FLUID WITH HOMOTHETIC SELF-SIMILARITY
Authors: BRANDT C. F. C. , DA SILVA M. F. A. , VILLAS DA ROCHA JAIME F. , CHAN R.
Published: September 2003

We study spacetimes of spherically symmetric anisotropic fluid with homothetic self-similarity. We find a class of solutions to the Einstein field equations by assuming that the tangential pressure of the fluid is proportional to its radial one and that the fluid moves along time-like geodesics. The energy conditions, and geometrical and physical properties of these solutions are studied and found that some of them represent gravitational collapse of an anisotropic fluid.
NAKED SINGULARITIES IN HIGHER DIMENSIONAL GRAVITATIONAL COLLAPSE
Authors: BANERJEE ASIT , DEBNATH UJJAL , CHAKRABORTY SUBENOY
Published: September 2003

Spherically symmetric inhomogeneous dust collapse has been studied in higher dimensional space–time and the factors responsible for the appearance of a naked singularity are analyzed in the region close to the centre for the marginally bound case. It is clearly demonstrated that in the former case naked singularities do not appear in the space–time having more than five dimension, which appears to a strong result. The non-marginally bound collapse is also examined in five dimensions and the role of shear in developing naked singularities in this space–time is discussed in details. The five-dimensional space–time is chosen in the later case because we have exact solution in closed form only in five dimension and not in any other case.
BIANCHI TYPE I ANISOTROPIC MAGNETIZED COSMOLOGICAL MODELS WITH VARYING Λ
Authors: PRADHAN ANIRUDH , PANDEY OM PRAKASH
Published: September 2003

Bianchi type I magnetized cosmological models in the presence of a bulk viscous fluid are investigated. The source of the magnetic field is due to an electric current produced along the x-axis. The distribution consists of an electrically neutral viscous fluid with an infinite electrical conductivity. The coefficient of bulk viscosity is assumed to be a power function of mass density. The cosmological constant Λ is found to be positive and is a decreasing function of time which is supported by results from recent supernovae observations. The behaviour of the models in the presence and the absence of magnetic field are also discussed.
α
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Integrin and Development of Atherosclerosis in a Mouse Model
Authors: Grenache David G. , Coleman Trey , Semenkovich Clay F. , Santoro Samuel A. , Zutter Mary M.
Published: September 2003

Objectives—

The α
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integrin serves as a collagen or collagen/laminin receptor on many cell types, including endothelial cells and platelets. Many studies indicate that the α
2
β
1
integrin is a critical mediator of platelet adhesion to collagen. Epidemiologic studies suggest a direct correlation between the genetically determined platelet surface density of the α
2
β
1
integrin and the risk of thrombotic diseases, such as myocardial infarction and stroke, in the young, which are well-established complications of atherosclerosis. We have now used the α
2
β
1
integrin–deficient mouse to evaluate the contributions of the α
2
β
1
integrin to the development of atherosclerosis.

Methods and Results—

We generated wild-type (α
2
+/+
) or α
2
β
1
integrin–deficient (α
2
−/−
) mice that were also deficient in the apolipoprotein E (ApoE) gene (ApoE
−/−
) and compared atherosclerotic lesion development in α
2
+/+
ApoE
−/−
and α
2
−/−
ApoE
−/−
mice that were fed a high-fat, cholesterol-containing diet for 6 or 15 weeks. Total lesional area did not differ significantly between the α
2
-null animals and the wild-type animals at either 6 or 15 weeks.

Conclusions—

Our results suggest that risk for arterial thrombotic disease associated with high-level α
2
β
1
integrin expression is not attributable to enhanced development of atherosclerosis per se but may rather be a consequence of thrombotic complications at the plaques.
Constrictive Pericarditis in 26 Patients With Histologically Normal Pericardial Thickness
Authors: Talreja Deepak R. , Edwards William D. , Danielson Gordon K. , Schaff Hartzell V. , Tajik A. Jamil , Tazelaar Henry D. , Breen Jerome F. , Oh Jae K.
Published: September 2003

Background—

Traditionally, increased pericardial thickness has been considered an essential diagnostic feature of constrictive pericarditis. Although constriction with a normal-thickness pericardium has been demonstrated clinically by noninvasive imaging, the details of clinicopathological correlates have not been described.

Methods and Results—

A total of 143 patients with proven constriction underwent pericardiectomy at Mayo Clinic between 1993 and 1999. Their baseline characteristics, operative data, and pathological specimens were reviewed retrospectively. The pericardium was of normal thickness (≤2 mm) in 26 patients (18%; group 1) and was thickened (>2 mm) in 117 (82%; group 2). The most common causes of constriction in group 1 included previous cardiac surgery, chest irradiation, previous infarction, and idiopathic disease. There was little difference in symptoms and findings on physical examination between the 2 groups. Microscopically, no patient had an entirely normal pericardium. Histopathological abnormalities in group 1 were mild and focal, including fibrosis, inflammation, calcification, fibrin deposition, and focal noncaseating granulomas. Pericardiectomy was equally effective in relieving symptoms regardless of the presence or absence of increased thickness.

Conclusions—

Pericardial thickness was not increased in 18% of patients with surgically proven constrictive pericarditis, although the histopathological appearance was focally abnormal in all cases. When clinical, echocardiographic, or invasive hemodynamic features indicate constriction in patients with heart failure, pericardiectomy should not be denied on the basis of normal thickness as demonstrated by noninvasive imaging.
Effects of Eplerenone, Enalapril, and Eplerenone/Enalapril in Patients With Essential Hypertension and Left Ventricular Hypertrophy
Authors: Pitt Bertram , Reichek Nathaniel , Willenbrock Roland , Zannad Faiez , Phillips Robert A. , Roniker Barbara , Kleiman Jay , Krause Scott , Burns Daniel , Williams Gordon H.
Published: September 2003

Background—

Elevated renin-angiotensin-aldosterone system activity correlates with left ventricular hypertrophy (LVH) and cardiovascular risk, but the relative contributions of angiotensin II and aldosterone remain unclear. This study compared LVH regression during treatment with the selective aldosterone blocker eplerenone, enalapril, and their combination in patients with hypertension.

Methods and Results—

A 9-month, double-blind, randomized study was performed in 202 patients with LVH and hypertension who received eplerenone 200 mg daily, enalapril 40 mg daily, or eplerenone 200 mg and enalapril 10 mg daily. At week 8, hydrochlorothiazide 12.5 to 25 mg and/or amlodipine 10 mg was added if diastolic blood pressure was >90 mm Hg. Change in left ventricular (LV) mass as assessed by MRI was the primary end point. Change in blood pressure, renin-angiotensin-aldosterone system hormones, albuminuria, and safety were also assessed. Eplerenone significantly reduced LV mass from baseline (−14.5±3.36 g; n=50) similarly to enalapril (−19.7±3.20 g; n=54;
P
=0.258), but eplerenone/enalapril (−27.2±3.39 g; n=49) was more effective than eplerenone alone (
P
=0.007). All treatments reduced systolic blood pressure and diastolic blood pressure from baseline (eplerenone, −23.8 and −11.9 mm Hg; enalapril, −24.7 and −13.4 mm Hg; and eplerenone/enalapril, −28.7 and −14.4 mm Hg,
P
=0.048, in systolic blood pressure compared with eplerenone alone). Cough was more common with enalapril than with eplerenone (
P
=0.033), and elevated potassium was more common with eplerenone.

Conclusions—

Eplerenone was as effective as enalapril in LVH regression and blood pressure control. The combination of eplerenone and enalapril was more effective in reducing LV mass and systolic blood pressure than eplerenone alone.
Cardiac Angiotensin-(1-7) in Ischemic Cardiomyopathy
Authors: Averill David B. , Ishiyama Yuichiro , Chappell Mark C. , Ferrario Carlos M.
Published: September 2003

Background—

Accumulating evidence suggests that angiotensin-(1-7) (Ang-[1-7]) may play an important role in counteracting the pressor, proliferative, and profibrotic actions of angiotensin II in the heart. Thus, we evaluated whether Ang-(1-7) is expressed in the myocardium of normal rats and those in which myocardial infarction was produced 4 weeks beforehand.

Methods and Results—

The left coronary artery in 10-week-old Lewis rats was either ligated (n=5) or exposed but not occluded in age-matched controls (sham; n=5). Left ventricular end-diastolic pressures were significantly elevated 4 weeks after myocardial infarction (25±1 versus 5±1 mm Hg for sham;
P
<0.001), whereas left ventricular systolic pressures were significantly reduced (ligated 86±4 versus sham 110±5 mm Hg;
P
<0.01). Hemodynamic effects of coronary artery ligation were accompanied by significant cardiac hypertrophy (heart weight to body weight: ligated 4.3±0.1 versus sham 2.9±0.1 mg/g;
P
<0.001). In both ligated and sham rats, Ang-(1-7) immunoreactivity was limited to cardiac myocytes and absent in interstitial cells and coronary vessels. Ang-(1-7) immunoreactivity was significantly augmented in ventricular tissue surrounding the infarct area in the heart of rats with myocardial infarction.

Conclusions—

Development of heart failure subsequent to coronary artery ligation leads to increased expression of Ang-(1-7),which was restricted to myocytes.
Dose-Dependent Acceleration of High-Density Lipoprotein Catabolism by Endothelial Lipase
Authors: Maugeais Cyrille , Tietge Uwe J.F. , Broedl Uli C. , Marchadier Dawn , Cain William , McCoy Mary G. , Lund-Katz Sissel , Glick Jane M. , Rader Daniel J.
Published: September 2003

Background—

Factors that regulate the metabolism of HDL and apolipoprotein A-I (apoA-I) are incompletely understood. Overexpression of endothelial lipase (EL) markedly reduces plasma levels of HDL cholesterol and apoA-I in mice, but the mechanisms of this effect remain unknown.

Methods and Results—

We used different doses of a recombinant adenoviral vector to overexpress human EL in mice and studied the effects on plasma phospholipase activity, plasma lipids, HDL particle size, HDL turnover, and tissue sites of HDL degradation in mice. Overexpression of EL was associated with a significant dose-dependent increase in postheparin plasma phospholipase activity. Plasma phospholipid, HDL cholesterol, and apoA-I levels were markedly decreased, even at the lowest dose of vector. Kinetic studies demonstrated a significant dose-dependent increase in the fractional catabolic rate of HDL-apolipoprotein in EL-overexpressing mice. The postheparin plasma phospholipase activity was significantly positively correlated with HDL-apolipoprotein fractional catabolic rate. The uptake of apoA-I by the kidney and the liver was significantly increased by 2.5-fold and 3-fold, respectively, in mice overexpressing EL.

Conclusions—

Expression of EL in mice results in a dose-dependent increase in postheparin plasma phospholipase activity, catabolic rate of HDL-apolipoprotein, and uptake of apoA-I in both kidney and liver.
Voltage and Activation Mapping
Authors: de Groot Natasja M.S. , Schalij Martin J. , Zeppenfeld Katja , Blom Nico A. , Van der Velde Enno T. , Van der Wall Ernst E.
Published: September 2003

Background—

Endocardial mapping is mandatory before radiofrequency catheter ablation (RFCA). Mapping can be performed with either unipolar or bipolar recordings. Impact of the recording technique used was studied in patients with and without structural heart disease using the 3D electroanatomic CARTO mapping system.

Methods and Results—

Patients (n=44; 16 males; age 43±16 years) referred for RFCA of atrial flutter (AFL, n=18), focal atrial tachycardia (FAT, n=4), AV nodal reentrant tachycardia (AVNRT, n=5), or scar-related atrial reentrant tachycardia (IART, n=17) were studied. Voltage and activation maps were constructed. Unipolar and bipolar voltage distribution in the different groups was studied to establish a cutoff voltage value to facilitate delineation of scar tissue. Electrograms were recorded during tachycardia (FAT: n=246, cycle length [CL]=449±35 ms; AVNRT: n=182, CL=359±47 ms; AFL: n=1164, CL=255±56 ms; IART: n=2431, CL=280±74 ms). Unipolar voltages were greater than bipolar voltages (
P
<0.001). Unipolar voltages ≤1.0 mV were equally distributed in both AFL and IART patients. Bipolar voltages ≤0.1 mV were only found in patients with IART, and subsequently 0.1 mV was used as the cutoff value to delineate scar tissue. No unipolar cutoff value could be established. Timing of unipolar and bipolar local activation was correlated in all patient groups.

Conclusions—

The recording technique used has considerable impact on reconstruction of reentrant pathways and on the outcome of RFCA. In general, unipolar and bipolar recordings provide complementary information; however, only bipolar recordings allow voltage-based scar tissue delineation in patients with congenital heart disease.
Arginase Reciprocally Regulates Nitric Oxide Synthase Activity and Contributes to Endothelial Dysfunction in Aging Blood Vessels
Authors: Berkowitz Dan E. , White Ron , Li Dechun , Minhas Khalid M. , Cernetich Amy , Kim Soonyul , Burke Sean , Shoukas Artin A. , Nyhan Daniel , Champion Hunter C. , Hare Joshua M.
Published: September 2003

Background—

Although abnormal
l
-arginine NO signaling contributes to endothelial dysfunction in the aging cardiovascular system, the biochemical mechanisms remain controversial.
l
-arginine, the NO synthase (NOS) precursor, is also a substrate for arginase. We tested the hypotheses that arginase reciprocally regulates NOS by modulating
l
-arginine bioavailability and that arginase is upregulated in aging vasculature, contributing to depressed endothelial function.

Methods and Results—

Inhibition of arginase with (S)-(2-boronoethyl)-
l
-cysteine, HCl (BEC) produced vasodilation in aortic rings from young (Y) adult rats (maximum effect, 46.4±9.4% at 10
−5
mol/L,
P
<0.01). Similar vasorelaxation was elicited with the additional arginase inhibitors
N
-hydroxy-nor-
l
-arginine (nor-NOHA) and difluoromethylornithine (DFMO). This effect required intact endothelium and was prevented by 1H-oxadiazole quinoxalin-1-one (
P
<0.05 and
P
<0.001, respectively), a soluble guanylyl cyclase inhibitor. DFMO-elicited vasodilation was greater in old (O) compared with Y rat aortic rings (60±6% versus 39±6%,
P
<0.05). In addition, BEC restored depressed
l
-arginine (10
−4
mol/L)–dependent vasorelaxant responses in O rings to those of Y. Arginase activity and expression were increased in O rings, whereas NOS activity and cyclic GMP levels were decreased. BEC and DFMO suppressed arginase activity and restored NOS activity and cyclic GMP levels in O vessels to those of Y.

Conclusions—

These findings demonstrate that arginase modulates NOS activity, likely by regulating intracellular
l
-arginine availability. Arginase upregulation contributes to endothelial dysfunction of aging and may therefore be a therapeutic target.