bluuebunny/crossref_metadata_2025 huggingface dataset:
Habitat use by breeding Tree Sparrows Passer montanus
Authors: FIELD ROB H. , ANDERSON GUY Q. A.
Published: November 2004

Tree Sparrows Passer montanus showed a strong preference for nest‐sites adjacent to wetland habitats, and avoidance of sites on intensively managed mixed farmland distant from Rutland Water. A variety of wetland edge habitats were frequently used by foraging adult birds when provisioning nestlings, and invertebrate prey of aquatic origin was frequently recorded in chick diet. We suggest that the wetland edge habitats at the study sites played a key role in providing adequate diversity and availability of suitable invertebrate prey to allow successful chick rearing throughout the long breeding season of this multi‐brooded passerine. It is possible that large areas of formerly occupied farmland in the UK no longer provide these invertebrate resources due to the effects of intensification in the late 20th century. There was no evidence that the availability of supplementary seed food within 1 km of the nest‐site influenced nest‐site choice, or affected productivity. It is probable that the importance of seed food resources to the persistence of Tree Sparrow populations operates on a larger spatial scale than that tested in this study, due to the greater mobility of Tree Sparrows in the non‐breeding season, when seed resources are most likely to be a key limiting factor. When considering conservation management aimed at recovering breeding populations of Tree Sparrows, the key resources of seed food, invertebrate food and nest‐sites must be made available at appropriate spatial scales.
Changes in breeding wader populations on lowland wet grasslands in England and Wales: causes and potential solutions
Authors: WILSON ANDY M. , AUSDEN MALCOLM , MILSOM TIM P.
Published: November 2004

Populations of waders breeding on lowland wet grassland in England and Wales have declined markedly in recent decades; the loss of once widespread species such as LapwingVanellus vanellus, SnipeGallinago gallinagoand RedshankTringa totanusfrom many areas is of particular conservation concern. These declines are due to loss of grassland to other land uses, and to significant changes in grassland management. Drainage, reseeding and changes in grazing regimes have all been particularly detrimental to lowland wet grassland in terms of a breeding habitat for waders. Careful management of key sites, many of them managed as nature reserves, has shown that wader declines can be halted or even reversed. Aspects of this management can be applied to larger areas through agri‐environment schemes, such as the Environmentally Sensitive Areas (ESA) scheme,Tir Gofal(in Wales) and Countryside Stewardship (in England) but these need be carefully targeted to ensure that the benefits for waders are maximized. In particular, it has been shown that higher tier management options within the ESA scheme (those that enhance the landscape) are more cost‐effective than lower tier options (those that maintain the landscape). The extent and suitability of lowland wet grassland will face further pressure in years to come as a result of climate change, the impacts of which need to be assessed and mitigated against.
ARCHAEOMETRIC STUDY OF PROTOHISTORIC GRINDING TOOLS OF VOLCANIC ROCKS FOUND IN THE KARST (ITALY–SLOVENIA) AND ISTRIA (CROATIA)*
Authors: ANTONELLI F. , BERNARDINI F. , CAPEDRI S. , LAZZARINI L. , KOKELJ E. MONTAGNARI
Published: November 2004

This paper presents the results of the archaeometric study of 30 grinding tools found in the Karst plateau (an area that spreads from the northeastern border of Italy to Slovenia) and in the Istria peninsula (Croatia). The petrographic and geochemical characteristics of the artefacts indicate that most of them would be made of trachytic volcanites extracted from the Euganean Hills, near Padua (Veneto). It is known that trachytic rocks from this area had been widely exploited in northern Italy during protohistoric times, but these data considerably enlarge the area of diffusion of saddle‐querns made of these rocks, extending it to Istria. Additionally, the likely provenance from Mount Etna of few other pieces of mugearites and hawaiites represents a new element, to be fully evaluated in the context of trans‐Adriatic exchange/trade connections. Analytical data and possible archaeological inferences are presented in detail in the text.
PHOSPHATES IN ARCHAEOLOGICAL FINDS: IMPLICATIONS FOR ENVIRONMENTAL CONDITIONS OF BURIAL*
Authors: MARITAN L. , MAZZOLI C.
Published: November 2004

The occurrence of coarse‐grained vivianite and mitridatite aggregates in a potsherd, a grand ring and a timber imprint from the Second Iron Age site of Adria (Rovigo, northeastern Italy) suggest contrasting environmental conditions of burial. In particular, bone fragments were replaced by vivianite at relatively low pH and Eh, due to the presence of deteriorating organic matter, together with slag and iron flakes. Subsequent interactions with Ca‐rich groundwater characterized by higher pH and Eh determined the growth of mitridatite after vivianite. Although phosphates crystallized after burial, the examined samples were not involved in pervasive chemical contamination.
Numerical Study of Mixed Convection Flow in an Impinging Jet CVD Reactor for Atmospheric Pressure Deposition of Thin Films
Authors: Vanka S. P. , Luo Gang , Glumac Nick G.
Published: November 2004

A systematic numerical study has been conducted of the mixed convection flow in a novel impinging jet chemical vapor deposition (CVD) reactor for deposition of thin films at atmospheric pressure. The geometry resembles that of a pancake reactor but the inflow gases enter through a small nozzle to provide high inlet momentum. A finite-volume-based computational procedure is used to integrate the governing flow, energy, and scalar transport equations with high accuracy. The effects of the temperature dependent properties are fully accounted for. The effects of operating pressure, wafer rotation rate, and inlet flow rate of the carrier gas are investigated. The main benefit of the new geometry is the suppression of the buoyancy-driven flow even at atmospheric pressures due to the lower mixed convection parameter. We show that the new geometry can produce thin films of high radial uniformity and also with high growth rate. Comparisons are also made with a conventional stagnation flow reactor for which it is shown that beyond a moderate pressure (∼0.1 atm), the flow is dominated by natural convection, and the reactor is unsuitable for practical use.
Mie Scattering Theory for Phonon Transport in Particulate Media
Authors: Prasher Ravi S.
Published: November 2004

Scattering theory for the scattering of phonons by particulate scatterers is developed in this paper. Recently the author introduced the generalized equation of phonon radiative transport (GEPRT) in particulate media, which included a phase function to account for the anisotropic scattering of phonons by particulate scatterer. Solution of the GEPRT showed that scattering cross section is different from the thermal transport cross-section. In this paper formulations for the scattering and transport cross section for horizontally shear (SH) wave phonon or transverse wave phonon without mode conversion is developed. The development of the theory of scattering and the transport cross section is exactly analogous to the Mie scattering theory for photon transport in particulate media. Results show that transport cross section is very different from the scattering cross section. The theory of phonon scattering developed in this paper will be useful for the predictive modeling of thermal conductivity of practical systems, such as nanocomposites, nano-micro-particle-laden systems, etc.
An Integral Equation for the Dual-Lag Model of Heat Transfer
Authors: Kulish Vladimir V. , Novozhilov Vasily B.
Published: November 2004

An integral relation is obtained between local temperature and local temperature gradient for the dual-lag model of heat transport, which substitutes classical Fourier law at short time scales. Both the heat flux lag and the temperature gradient lag are considered, however, it is shown that only difference between the two affects temperature profile. Being applied at exposed surface of material, the integral equation predicts surface temperature variation for any form of imposed heat flux. The solution is tested considering solid heating by a picosecond laser impulse. Results are compared with the classical solution of the parabolic heat transfer equation and available experimental data.
Experimental Investigation of Gas Flow in Microchannels
Authors: Turner Stephen E. , Lam Lok C. , Faghri Mohammad , Gregory Otto J.
Published: November 2004

This paper presents an experimental investigation of laminar gas flow through microchannels. The independent variables: relative surface roughness, Knudsen number and Mach number were systematically varied to determine their influence on the friction factor. The microchannels were etched into silicon wafers, capped with glass, and have hydraulic diameters between 5 and 96 μm. The pressure was measured at seven locations along the channel length to determine local values of Knudsen number, Mach number and friction factor. All measurements were made in the laminar flow regime with Reynolds numbers ranging from 0.1 to 1000. The results show close agreement for the friction factor in the limiting case of low Ma and low Kn with the incompressible continuum flow theory. The effect of compressibility is observed to have a mild (8 percent) increase in the friction factor as the Mach number approaches 0.35. A 50 percent decrease in the friction factor was seen as the Knudsen number was increased to 0.15. Finally, the influence of surface roughness on the friction factor was shown to be insignificant for both continuum and slip flow regimes.
Ralstonia solanacearum
Iron Scavenging by the Siderophore Staphyloferrin B Is Controlled by PhcA, the Global Virulence Regulator
Authors: Bhatt Garima , Denny Timothy P.
Published: November 2004

PhcA is a transcriptional regulator that activates expression of multiple virulence genes in the plant pathogen
Ralstonia solanacearum
. Relative to their wild-type parents,
phcA
mutants overproduced iron-scavenging activity detected with chrome azurol S siderophore detection medium. Transposon mutagenesis of strain AW1-PC (
phcA1
) generated strain GB6, which was siderophore negative but retained weak iron-scavenging activity. The
ssd
gene inactivated in GB6 encodes a protein similar to group IV amino acid decarboxylases, and its transcription was repressed by iron(III) and PhcA.
ssd
is the terminal gene in a putative operon that also appears to encode three siderophore synthetase subunits, a integral membrane exporter, and three genes with no obvious role in siderophore production. A homologous operon was found in the genomes of
Ralstonia metallidurans
and
Staphylococcus aureus
, both of which produce the polycarboxylate siderophore staphyloferrin B. Comparison of the siderophores present in culture supernatants of
R. solanacearum
,
R. metallidurans
, and
Bacillus megaterium
using chemical tests, a siderophore utilization bioassay, thin-layer chromatography, and mass spectroscopy indicated that
R. solanacearum
produces staphyloferrin B rather than schizokinen as was reported previously. Inactivation of
ssd
in a wild-type AW1 background resulted in a mutant almost incapable of scavenging iron but normally virulent on tomato plants. AW1 did not produce siderophore activity when cultured in tomato xylem sap, suggesting that the main location in tomato for
R. solanacearum
during pathogenesis is iron replete.
Negative Transcriptional Regulation of the
ilv-leu
Operon for Biosynthesis of Branched-Chain Amino Acids through the
Bacillus subtilis
Global Regulator TnrA
Authors: Tojo Shigeo , Satomura Takenori , Morisaki Kaori , Yoshida Ken-Ichi , Hirooka Kazutake , Fujita Yasutaro
Published: November 2004

The
Bacillus subtilis ilv-leu
operon is involved in the synthesis of branched-chain amino acids (valine, isoleucine, and leucine). The two- to threefold repression of expression of the
ilv-leu
operon during logarithmic-phase growth under nitrogen-limited conditions, which was originally detected by a DNA microarray analysis to compare the transcriptomes from the wild-type and
tnrA
mutant strains, was confirmed by
lacZ
fusion and Northern experiments. A genome-wide TnrA box search revealed a candidate box approximately 200 bp upstream of the transcription initiation base of the
ilv-leu
operon, the TnrA binding to which was verified by gel retardation and DNase I footprinting analyses. Deletion and base substitution of the TnrA box sequence affected the
ilv-leu
promoter activity in vivo, implying that TnrA bound to the box might be able to inhibit the promoter activity, possibly through DNA bending. The negative control of the expression of the
ilv-leu
operon by TnrA, which is considered to represent rather fine-tuning (two- to threefold), is a novel regulatory link between nitrogen and amino acid metabolism.
Effector-Mediated Interaction of CbbR
I
and CbbR
II
Regulators with Target Sequences in
Rhodobacter capsulatus
Authors: Dubbs Padungsri , Dubbs James M. , Tabita F. Robert
Published: November 2004

In
Rhodobacter capsulatus
, genes encoding enzymes of the Calvin-Benson-Bassham reductive pentose phosphate pathway are located in the

cbb
I

and

cbb
II

operons. Each operon contains a divergently transcribed LysR-type transcriptional activator (CbbR
I
and CbbR
II
) that regulates the expression of its cognate
cbb
promoter in response to an as yet unidentified effector molecule(s). Both CbbR
I
and CbbR
II
were purified, and the ability of a variety of potential effector molecules to induce changes in their DNA binding properties at their target promoters was assessed. The responses of CbbR
I
and CbbR
II
to potential effectors were not identical. In gel mobility shift assays, the affinity of both CbbR
I
and CbbR
II
for their target promoters was enhanced in the presence of ribulose-1,5-bisphosphate (RuBP), phosphoenolpyruvate, 3-phosphoglycerate, 2-phosphoglycolate. ATP, 2-phosphoglycerate, and KH
2
PO
4
were found to enhance only CbbR
I
binding, while fructose-1,6-bisphosphate enhanced the binding of only CbbR
II
. The DNase I footprint of CbbR
I
was reduced in the presence of RuBP, while reductions in the CbbR
II
DNase I footprint were induced by fructose-1,6-bisphosphate, 3-phosphoglycerate, and KH
2
PO
4
. The current in vitro results plus recent in vivo studies suggest that CbbR-mediated regulation of
cbb
transcription is controlled by multiple metabolic signals in
R. capsulatus
. This control reflects not only intracellular levels of Calvin-Benson-Bassham cycle metabolic intermediates but also the fixed (organic) carbon status and energy charge of the cell.
Unmasking Novel Sporulation Genes in
Bacillus subtilis
Authors: Silvaggi Jessica M. , Popham David L. , Driks Adam , Eichenberger Patrick , Losick Richard
Published: November 2004

The
Bacillus subtilis
transcription factor σ
E
directs the expression of a regulon of 262 genes, but null mutations in only a small fraction of these genes severely impair sporulation. We have previously reported that mutations in seven σ
E
-controlled genes cause a mild (2- to 10-fold) defect in sporulation. In this study, we found that pairwise combinations of some of these seven mutations led to strong synthetic sporulation phenotypes, especially those involving the
ytrHI
operon and
ybaN
. Double mutants of
ybaN
and
ytrH
and of
ybaN
and
ytrI
had >10,000-fold lower sporulation efficiencies than the wild type. Thin-section electron microscopy revealed a block in cortex formation for the
ybaN ytrH
double mutant and coat defects for the
ybaN
single and
ybaN ytrI
double mutants. Sporulating cells of a
ybaN ytrI
double mutant and of a
ybaN ytrHI
triple mutant exhibited a pronounced loss of dipicolinic acid (DPA) between hours 8 and 24 of sporulation, in contrast to the constant levels seen for the wild type. An analysis of the spore cortex peptidoglycans of the
ybaN ytrI
and
ybaN ytrHI
mutants showed striking decreases in the levels of total muramic acid by hour 24 of sporulation. These data, along with the loss of DPA in the mutants, suggest that the developing spores were unstable and that the cortex underwent degradation late in sporulation. The existence of otherwise hidden sporulation pathways indicates that functional redundancy may mask the role of hitherto unrecognized sporulation genes.
CLASSIFICATION OF IMPULSE RADAR WAVEFORMS USING NEURAL NETWORKS
Authors: VRCKOVNIK G. , CHUNG T. , CARTER C.R.
Published: November 2004

In this paper, it is demonstrated that multilayer neural networks, trained with the backpropagation algorithm and radial basis functions, can classify impulse radar waveforms from three different asphalt-covered bridge decks, each with its own structure. It might be thought that the thickness of asphalt and the depth of concrete over the reinforcing bars would be nearly constant for any one bridge deck; however in practice this is not the case. There are often significant changes in the thickness of the asphalt and the cover over reinforcement. Furthermore, a certain amount of damage to the concrete caused by severe winter climate often produces a random variation in the reflected waveforms obtained from different locations. These factors lead to a significant number of combinations of waveforms that can be obtained from any given structural type of deck. The classification accuracies achieved ranged between 89.9% and 100%. The accuracies achieved after using principal components analysis to reduce the dimensionality of the input data ranged between 95.6% and 100%.
OPTIMAL HEBBIAN LEARNING RULES AND THE ROLE OF ASYMMETRY
Authors: STARIOLO D.A. , TSALLIS C.
Published: November 2004

We study the storage properties associated with generalized Hebbian learning rules which present four free parameters that allow for asymmetry. We also introduce two extra parameters in the post-synaptic potentials in order to further improve the critical capacity. Using signal-to-noise analysis, as well as computer simulations on an analog network, we discuss the performance of the rules for arbitrarily biased patterns and find that the critical storage capacity αc becomes maximal for a particular symmetric rule (αc diverges in the sparse coding limit). Departures from symmetry decrease αc butcan increase the robustness of the model.
CONSTRAINED LEARNING VECTOR QUANTIZATION
Authors: YAN HONG
Published: November 2004

Kohonen’s learning vector quantization (LVQ) is an efficient neural network based technique for pattern recognition. The performance of the method depends on proper selection of the learning parameters. Over-training may cause a degradation in recognition rate of the final classifier. In this paper we introduce constrained learning vector quantization (CLVQ). In this method the updated coefficients in each iteration are accepted only if the recognition performance of the classifier after updating is not decreased for the training samples compared with that before updating, a constraint widely used in many prototype editing procedures to simplify and optimize a nearest neighbor classifier (NNC). An efficient computer algorithm is developed to implement this constraint. The method is verified with experimental results. It is shown that CLVQ outperforms and may even require much less training time than LVQ.
CLASSIFICATION OF GENETIC SEQUENCES WITH BACKPROPAGATION
Authors: LENDE R. , CSERNAI L.P. , KAMP D.
Published: November 2004

A backpropagation algorithm is used to train a neural net with the goal of distinguishing between two groups of biological species: prokaryotic and eukaryotic, based on frequencies of all 16 doublets in DNA sequences. An improvement of about 15% is obtained compared to statistical analysis based on one doublet only. This is done first by presenting sequences of species to the network with known classification (the training phase) and then showing species which the neural net has never seen before, and looking for the response. A brief discussion of the speed of training is given.
MULTI-EXPERT AND HYBRID CONNECTIONIST APPROACH FOR PATTERN RECOGNITION: SPEAKER IDENTIFICATION TASK
Authors: BENNANI YOUNÈS
Published: November 2004

This paper presents and evaluates a modular/hybrid connectionist system for speaker identification. Modularity has emerged as a powerful technique for reducing the complexity of connectionist systems, allowing a priori knowledge to be incorporated into their design. In problems where training data are scarce, such modular systems are likely to generalize significantly better than a monolithic connectionist system. In addition, modules are not restricted to be connectionist: hybrid systems, with e.g. Hidden Markov Models (HMMs), can be designed, combining the advantages of connectionist and non-connectionist approaches. Text independent speaker identification is an inherently complex task where the amount of training data is often limited. It thus provides an ideal domain to test the validity of the modular/hybrid connectionist approach. An architecture is developed in this paper which achieves this identification, based upon the cooperation of several connectionist modules, together with an HMM module. When tested on a population of 102 speakers extracted from the DARPA-TIMIT database, perfect identification was obtained. Overall, our recognition results are among the best for any text-independent speaker identification system handling this population size. In a specific comparison with a system based on multivariate auto-regressive models, the modular/hybrid connectionist approach was found to be significantly better in terms of both accuracy and speed. Our design also allows for easy incorporation of new speakers.
HIGHER MOMENTS IN CONFORMAL TURBULENCE
Authors: CHEN CHIA-CHU
Published: November 2004

Physical consequences of conformal turbulence are obtained by calculating higher moments in the inertial range with constant enstrophy flux cascade. We have also studied the boundary effects in these higher moments. Our results show deviations from Kolmogorov-type scaling laws.
FULL ONE-LOOP SUPERSYMMETRIC QUANTUM EFFECTS ON Mw
Authors: GARCÍA DAVID , SOLÀ JOAN
Published: November 2004

We present a detailed numerical analysis of a fully-fledged computation of one-loop supersymmetric quantum effects on the mass of the weak gauge boson W± in the standard on-shell renormalization scheme based on the input parameters (GF, α, MZ). The importance of the process-dependent contributions as compared to the universal effects is assessed. The final numerical results show that in large regions of parameter space the potential radiative shifts [Formula: see text] could be within the level of precision expected at LEP II, depending on the model considered. A comparison is made with other renormalization frameworks.
CAN γγ → ZLZL SERVE AS A PROBE OF THE ELECTROWEAK SYMMETRY BREAKING SECTOR?
Authors: ROSENFELD ROGERIO
Published: November 2004

We investigate the feasibility of distinguishing among different models of electroweak symmetry breaking by studying the process γγ → Z L Z L at photon colliders. For models with a low mass Higgs-like scalar resonance, the s-channel contribution provides a distinct resonance structure and large cross-sections. However, the absence of a resonance structure in the cross-section for the above process does not discriminate in principle between the existence of either a heavy Higgs boson or a vector resonance of a nonlinearly realized symmetry.
FLAVOR LEPTON NUMBER VIOLATION AT LEP2
Authors: KRASNIKOV N. V.
Published: November 2004

We show that in some supersymmetric models with explicit flavor number violation due to soft supersymmetry breaking terms there is strong flavor lepton number violation in slepton decays due to slepton mixing. If sleptons are relatively light (m sl ≤ MZ) flavor lepton number violation could be discovered at LEP2.
A NOTE ON THE RELATION BETWEEN DIFFERENT FORMS OF SUPERPARTICLE DYNAMICS
Authors: CEDERWALL MARTIN
Published: November 2004

A formulation of D = 10 superparticle dynamics is given that contain space-time and twistor variables. The set of constraints is entirely first class, and gauge conditions may be imposed that reduce the system to a Casalbuoni-Brink-Schwarz superparticle, a spinning particle or a twistor particle.
GAUSS DECOMPOSITION, WAKIMOTO REALIZATION AND GAUGED WZNW MODELS
Authors: ARFAEI H. , MOHAMMEDI N.
Published: November 2004

The implications of gauging the Wess-Zumino-Novikov-Witten (WZNW) model using the Gauss decomposition of the group elements are explored. We show that, contrary to the standard gauging of WZNW models, this gauging is carried out by minimally coupling the gauge fields. We find that this gauging, in the case of gauging and Abelian vector subgroup, differs from the standard one by terms proportional to the field strength of the gauge fields. We prove that gauging an Abelian vector subgroup does not have a nonlinear sigma model interpretation. This is because the target-space metric resulting from the integration over the gauge fields is degenerate. We demonstrate, however, that this kind of gauging has a natural interpretation in terms of Wakimoto variables.
TOPOLOGICAL CLASSIFICATION OF ODD-PARITY SPHALERON DEFORMATIONS
Authors: AXENIDES MINOS , JOHANSEN ANDREI
Published: November 2004

We discuss topological aspects of the electroweak sphaleron and its odd-parity deformations. We demonstrate that they are uniquely classified in terms of their odd or even-parity pure gauge field behavior at spatial infinity. Fermion level crossing occurs only for odd-parity configurations, which are topologically disconnected from the vacuum. They contribute to the high temperature unsuppressed baryon violating thermal transitions. Deformations with even-parity pure gauge behavior at spatial infinity are topologically trivial and do not mediate baryon number violation in the early universe.
AZIMUTHAL DEPENDENCE OF ENERGY FLOW IN CENTRAL COLLISIONS OF HEAVY NUCLEI
Authors: HARTNACK C. , AICHELIN J. , STÖCKER H. , GREINER W.
Published: November 2004

Microscopic VUU and QMD calculations, which include the momentum dependence of the nuclear interactions, both predict the observed collective off-plane squeeze-out of nuclear matter in heavy ion collisions. A strong projectile mass dependence is found, in agreement with the data. A fragment mass dependence of the emission pattern is predicted. The off-plane squeeze-out is sensitive to the bulk properties of hot and dense nuclear matter, namely the nuclear viscosity and the equation of state.
DOUBLE RADIATIVE DECAY $Z \to f\bar f\gamma \gamma $ IN THE STANDARD MODEL
Authors: MIKHEEV N.V. , PARKHOMENKO A. YA.
Published: November 2004

Z-boson decay [Formula: see text] in the Standard Model is analyzed. The distribution function on the invariant masses of the photon and fermion pairs is calculated in the leading logarithmic approximation. It is shown that this distribution function has a specific shape of a “crest.”
THE EFFECTIVE ACTION FOR THE THIRRING GROSS-NEVEU MODEL IN (2+1) DIMENSIONS
Authors: DE MELLO E.R. BEZERRA , RIBEIRO R.F.
Published: November 2004

We obtain in the leading order of 1/N expansion, the fermion-fermion effective potential for the three-dimensional model of (N) massless Dirac spinors with a general current and scalar quadrilinear self-interaction. Analyzing the Schrödinger equation in the presence of the nonrelativistic limit of this potential, we show that this system presents a fermionfermion bound state.
THE BEHAVIOR OF THE SLOPE OF ELASTIC NUCLEON SCATTERING AT SMALL TRANSFER MOMENTA AND RECENT UA4/2 DATA
Authors: GOLOSKOKOV S.V. , KULESHOV S.P. , SELYUGIN O.V.
Published: November 2004

Theoretical predictions for the behavior of the slope of nucleon-nucleon scattering and another parameters of the differential cross-sections in the framework of dynamic model are compared with the recent UA4/2 data at small transfer momenta and at the centerof-mass energy of 541 GeV. The predictions at superhigh energies are considered.
ON THE COMMON EIGENVECTORS OF TWO-MODE CREATION OPERATORS AND THE CHARGE OPERATOR
Authors: HONG-YI FAN , KLAUDER JOHN R.
Published: November 2004

Some comments are presented on the equivalence between Dirac’s ξ-representation of a harmonic oscillator (Ref. 5) and the eigenvectors of a creation operator derived by Fan et al. using Heitler’s contour integration form of δ-function. On the basis of this analysis the common eigenvectors of a†b† and Q=a†a−b†b, which are dual vectors of the charged coherent states of Bhaumik et al., are constructed.
DUALITY OF THE SUPERSTRING IN SUPERSPACE
Authors: DAS ASHOK , MAHARANA JNANADEVA
Published: November 2004

The evolution of a closed NSR string is considered in the background of constant graviton and antisymmetric fields. The σ-model action is written in a manifestly supersymmetric form in terms of superfields. The first order formalism adopted for the closed bosonic string is generalized to implement duality transformations and the constant dual backgrounds are obtained for the dual theory. We recover the G→G−1 duality for the case when antisymmetric tensor field is set to zero. Next, the case when the backgrounds depend on one superfield, is also analyzed. This scenario is similar to the cosmological case envisaged for the bosonic string. The explicit form of the duality transformation is given for this case.
PHOTON PART OF QUANTUM ACTION FUNCTIONAL IN QED
Authors: GOLFAND YU.A.
Published: November 2004

The photon part of the quantum action functional in QED is investigated using the effective functional Seff instead of the classical action Sph in the standard functional equations. All powers of the electromagnetic field strengths appear in Seff, so the special representation of the quantum action, proposed recently7 must be constructed according to the general theory. The dependence of Seff on the electromagnetic field strengths has been investigated.
THE ZERO TENSION LIMIT OF THE VIRASORO ALGEBRA AND THE CENTRAL EXTENSION
Authors: LIZZI F.
Published: November 2004

We argue that the Virasoro algebra for the closed bosonic string can be cast in a form which is suitable for the limit of vanishing string tension. In this form the limit of the Virasoro algebra gives the null string algebra. The anomalous central extension is seen to vanish as well when T→0.
Q-EXACT ACTIONS FOR BF THEORIES
Authors: BROOKS ROGER , LUCCHESI CLAUDIO
Published: November 2004

The actions for all classical (and consequently quantum) BF theories on n-manifolds is proven to be given by anti-commutators of hermitian, nilpotent, scalar fermionic charges with Grassmann-odd functionals. In order to show this, the space of fields in the theory must be enlarged to include “mass terms” for new, non-dynamical, Grassmann-odd fields. The implications of this result on observables are examined.
PROTON ELECTROMAGNETIC FORM FACTOR NEAR THE PROTON-ANTIPROTON THRESHOLD
Authors: MESHCHERYAKOV G.V. , MESHCHERYAKOV V.A.
Published: November 2004

The influence of the [Formula: see text]-state in the unitarity condition on the behavior of the proton form factor in the time-like region is studied. The contribution of the quasi-nuclear bound state discovered earlier in the elastic [Formula: see text]-channel to the proton electromagnetic form factor is estimated. This result well describes high precision data of the experiment PS-170 performed at LEAR and indicates quantum numbers of a possible quasi-nuclear [Formula: see text] bound state near the threshold.
GRAVITATIONAL EFFECTS IN A LONG SOLENOID
Authors: IVANOV B.V.
Published: November 2004

The gravity field induced by the magnetic field in an infinite solenoid is found. Gravitational effects are studied, the most important of them being the radial acceleration of neutral particles. It becomes equal to the earth’s acceleration for magnetic fields with strength 2×1014 G.
REMARK ON CONTACT INTERACTION OF SUPERSYMMETRIC ANYONS
Authors: ROY P.
Published: November 2004

We examine the possibility of contact interaction of anyons within the framework of a two-particle supersymmetric model. It is shown that anyons can be realized in a supersymmetric manner (except in two low lying states) and they do not feel contact interaction.
CHIRAL BOSONIZED ACTION AND THE MINIMAL WESS-ZUMINO-WITTEN ACTION FOR CHIRAL TWO-DIMENSIONAL QCD FROM PATH-INTEGRAL METHOD
Authors: ZHOU JIAN-GE , MIAO YAN-GANG , LIU YAO-YANG
Published: November 2004

The path-integral method is applied to derive the chiral bosonized action and the minimal WZW action for chiral QCD2. An interesting feature in our model is that the Poisson brackets of the new set of constraints, which is a recombination of the original ones, are field-independent on the constraint surface. The correct contribution from det {Ωi, Ωj} or δ(Ωa) is considered, and it seems to affect the properties of the integration measure. Here Ωi are the original chiral constraints, Ωa are linear combination of Ωi. However, due to the determinants of Lab(ɸ) and [Formula: see text] (the definition of Lab(ɸ) and [Formula: see text] can be seen from Eqs. (22) and (41)) being ±1, the right-invariant measure is equivalent to the left-invariant measure, which is quite unlike the case of the gauge quasigroup. As a result, we can identify the integration measure in our model with the Haar measure.
CHARGE ASYMMETRY OF PARTON DISTRIBUTIONS
Authors: RODIONOV E.N. , THOMAS A.W. , LONDERGAN J.T.
Published: November 2004

We calculate the valence distribution of down quarks in the proton and up quarks in the neutron (the ‘minority’ quark distributions), taking into consideration the major sources of charge symmetry violation, including the effect of the mass difference of the u and d quarks on the bag wave function, and the masses of the intermediate diquark states. The relative difference of the distributions can be as large as 10% for intermediate values of Bjorken x.
MIRROR MAPS AND INSTANTON SUMS FOR COMPLETE INTERSECTIONS IN WEIGHTED PROJECTIVE SPACE
Authors: KLEMM ALBRECHT , THEISEN STEFAN
Published: November 2004

We consider a class of Calabi-Yau compactifications which are constructed as a complete intersection in weighted projective space. For manifolds with one Kähler modulus we construct the mirror manifolds and calculate the instanton sum.
A HYPOTHETICAL, ATTRACTIVE LONG-RANGE FORCE FROM TWO-GLUON EXCHANGE, AND THE MEASUREMENT OF ρ IN HIGH ENERGY $\bar p p$ ELASTIC SCATTERING
Authors: BARSHAY S. , GRIFOLS J.A. , TORTOSA S.
Published: November 2004

The dynamical question is raised of the possible existence of long-range, residual attractive forces between hadrons due to the overall color-neutral exchange of two, massless transverse gluons between their constituents. Such a force between fermionic constituents would behave as 1/R6. We discuss the experiments which measure the real part of the nuclear amplitude, through its interference with the Coulomb amplitude in high energy [Formula: see text] elastic scattering at very small momentum transfers. We show that on-going [Formula: see text] experiments at [Formula: see text] and at 1800 GeV are sensitive to the scattering amplitude from a residual long-range force.
NUMBER THEORY AND QUANTUM MECHANICS
Authors: CHANG DARWIN , PAL PALASH B.
Published: November 2004

We demonstrate a simple contradiction of naive deterministic theories with quantum mechanics by showing that the spin components cannot have deterministic values for many values of the total spin of a particle. Using a theorem in number theory, we work out the complete set of spin values which display such properties. The fact that the set is infinite should prompt some modifications in the usual statement about achieving the classical limit when the value of angular momentum becomes very large.
INTERNAL SELF-CONSISTENCY OF WEAK NEUTRAL CURRENT DATA AT LEP/SLC FAVORS PHYSICS BEYOND STANDARD MODEL
Authors: AZIZ TARIQ
Published: November 2004

The recent measurements of Rb=Γb/Γhad together with other experimentally independent measurements of weak neutral current observables at LEP/SLC, display excellent internal self-consistency if the top dependent [Formula: see text] vertex correction is ignored. Extending this consistency further, the possibility of ignoring even the propagator/oblique corrections is not ruled out. Being a clean top mass indicator within SM, free from Higgs and strong interaction uncertainty, a comparison of Rb with the directly measured top quark mass at Tevatron clearly strengthens the above view. To preserve the weak radiative corrections of SM origin, for which evidence exists from measurements at low energies, independent of LEP/SLC, the most natural choice would be to invoke new radiative corrections of opposite sign from physics beyond SM. We stress that an improved measurement of Rb at LEP/SLC together with the direct measurement of top quark mass at Tevatron will play a clean and decisive role in this direction.
THE MFF SINGULAR VECTORS IN TOPOLOGICAL CONFORMAL THEORIES
Authors: SEMIKHATOV A.M.
Published: November 2004

It is argued that singular vectors of the topological conformal (twisted N=2) algebra are identical with singular vectors of the sl(2) Kac-Moody algebra. The derivation uses the (twisted) Kazama-Suzuki model associated with sl(2)/u(1). This Kazama-Suzuki construction can also be combined with the realization of topological symmetry in matter+gravity theories to produce a representation for the sl(2) current algebra in terms of an arbitrary minimal matter dressed with additional fields. The Malikov-Feigin-Fuchs (MFF) formula for sl(2) singular vectors translates into a general expression for topological singular vectors in matter+gravity theories. The MFF/topological singular states are observed to vanish in Witten’s free-field construction of the (twisted) N=2 algebra, derived from the Landau-Ginzburg formalism.
SPHERICALLY SYMMETRIC RADIATING SHELLS AND POST-NEWTONIAN APPROXIMATION
Authors: AQUILANO ROBERTO O. , CASTAGNINO MARIO A. , NEIRA LUIS P.
Published: November 2004

A recipe to use post-Newtonian approximation in the case of the shell dynamics is found. The obtained motion equation coincide with the exact one.
THE CHIRAL LAGRANGIAN APPROACH TO THE NON-UNIVERSAL EFFECTS IN THE $Z b \bar b$ VERTEX
Authors: ZHANG X.
Published: November 2004

We calculate the top quark loop corrections to the [Formula: see text] vertex in the chiral Lagrangian of the dynamical electroweak symmetry breaking theory. We use the effective Lagrangian based on coset space SU(2)×U(1)/U(1) with the electroweak gauge interaction switched off, so these corrections are directly related to the physics associated with the heavy top quark and the mass generation in the dynamical models.
A GENERALIZED MODEL FOR TWO-DIMENSIONAL QUANTUM GRAVITY AND DYNAMICS OF RANDOM SURFACES FOR d>1
Authors: MARTELLINI M. , SPREAFICO M. , YOSHIDA K.
Published: November 2004

The possible interpretations of a new continuum model for the two-dimensional quantum gravity for d>1 (d=matter central charge), obtained by carefully treating both diffeomorphism and Weyl symmetries, are discussed. In particular we note that an effective field theory is achieved in low energy (large area) expansion, that may represent smooth self-avoiding random surfaces embedded in a d-dimensional flat space-time for arbitrary d. Moreover the values of some critical exponents are computed, that are in agreement with some recent numerical results.
RESONANCE PRODUCTION IN PERIPHERAL HEAVY-ION COLLISIONS
Authors: NATALE A.A.
Published: November 2004

Heavy-ion collisions at ultrarelativistic energies may be used as a powerful source of photons and pomerons. We compute the rates for pseudoscalar meson production through two-photon and two-pomeron scattering, at energies that will be available at RHIC and LHC. Light mesons will mostly be produced by pomeron fusion at large rates, the two processes are comparable for charmed mesons, while electromagnetic production will be dominant for bottom mesons. We discuss the possibility of observing the reaction γγ(PP)→R→γγ, and comment on the particular case where R could be a scalar resonance at 650 MeV.
ZERO MODE DIVERGENCE PROBLEM IN STRING THEORY
Authors: NATSUUME MAKOTO
Published: November 2004

For 2D string theory, the perturbative S-matrices are not well-defined due to a zero mode divergence. Although there exist formal procedures to make the integral convergent, their physical meanings are not clear. We describe a method to obtain finite S-matrices physically to justify the formal schemes. The scheme uses asymptotic states by wave packets which fall faster than exponentials. It is shown that the scheme gives well-defined S-matrices and justifies the formal shifted Virasoro-Shapiro amplitude for simple processes. The tree-level unitarity for these processes is also shown. We point out a problem in this scheme.
QUANTUM INTEGRALS OF MOTION FOR THE HEISENBERG SPIN CHAIN
Authors: GRABOWSKI MAREK P. , MATHIEU PIERRE
Published: November 2004

An explicit expression for all the quantum integrals of motion for the isotropic Heisenberg s=1/2 spin chain is presented. The conserved quantities are expressed in terms of a sum over simple polynomials in spin variables. This construction is direct and independent of the transfer matrix formalism. Continuum limits of these integrals in both ferromagnetic and antiferromagnetic sectors are briefly discussed.
EXACT BETHE ANSATZ SOLUTION FOR An−1 CHAINS WITH NON-SUq(n) INVARIANT OPEN BOUNDARY CONDITIONS
Authors: de VEGA H.J. , GONZÁLEZ-RUIZ A.
Published: November 2004

The nested Bethe ansatz is generalized to open and independent boundary conditions depending on two continuous and two discrete free parameters. This is used to find the exact eigenvectors and eigenvalues of the An−1 vertex models and SU (n) spin chains with such boundary conditions. The solution is found for all diagonal families of solutions to the reflection equations in all possible combinations. The Bethe ansatz equations are used to find the first order finite size correction.
CHIRAL INVARIANCE OF MASSIVE FERMIONS
Authors: DAS ASHOK , HOTT MARCELO
Published: November 2004

We show that a massive fermion theory, while not invariant under the conventional chiral transformation, is invariant under a m-deformed chiral transformation. These transformations and the associated conserved charges are nonlocal but reduce to the usual transformations and charges when m=0. The m-deformed charges commute with helicity and satisfy the conventional chiral algebra.
NEW CONFORMAL MODELS WITH c<2/5
Authors: LASHKEVICH M. YU.
Published: November 2004

The zoo of two-dimensional exactly solvable conformal models has been supplemented by a series of nonunitary conformal models obtained by cosetting minimal models. Some of them coincide with minimal models, some do not even have Kac spectrum of conformal dimensions.
ALPHA STAGGERING: RELATIVISTIC MEAN FIELD DESCRIPTION
Authors: WARRIER LATHA S. , MAHARANA J.P. , GAMBHIR Y.K.
Published: November 2004

The α-staggering for the nuclei in the 2p−1f region is investigated in the relativistic mean field approach. The observed behavior similar to the well known odd-even staggering is well reproduced. The decomposition of densities for these nuclei shows almost identical characteristics beyond the rms radii indicating that the alpha cluster, if exists, is confined to the surface, as expected.
TWO-LOOP BETA-FUNCTION FOR NONLINEAR SIGMA-MODEL WITH AFFINE METRIC MANIFOLD
Authors: TARASOV VASILY E.
Published: November 2004

Two-loop metric counterterms for nonlinear two-dimensional bosonic σ-model with affine metric target manifold are calculated. The correlation of the metric and affine connection is derived from conformal invariance condition for nonlinear σ-model which is considered as a dissipative system. Examples of non-flat non-Riemannian manifolds resulting in trivial metric beta-function are suggested.
FRITZSCH-LIKE QUARK MASS MATRICES WITH DECOUPLED u QUARK
Authors: GILL P.S. , GUPTA MANMOHAN
Published: November 2004

Fritzsch-like Hermitian quark mass matrices with decoupled u quark as well as nonzero 22-elements, both in ‘U’ and ‘D’ sectors, have been considered to reconcile the data regarding [Formula: see text] and CKM matrix elements. Exploiting the idea of maximality of CP-violation, we find two interesting relations between CKM matrix elements, viz. |Vtd|≅ |Vus||Vcb|, |Vub|≅ ½(ms/ mb)|Vus|. Apart from obtaining 0.05≤|Vub/Vcb|≤0.12 and [Formula: see text], we find CP-violating rephasing invariant parameter |J|≅(3–5)×10−5. The predicted |Vtd| value implies almost maximal mixing in [Formula: see text] system.
COVARIANT PHASE SPACE FORMULATIONS OF SUPERPARTICLES AND SUPERSYMMETRIC WZW MODELS
Authors: AU G. , SPENCE B.
Published: November 2004

We present new covariant phase space formulations of superparticles moving on a group manifold, deriving the fundamental Poisson brackets and current algebras. We show how these formulations naturally generalize to the supersymmetric Wess-Zumino-Witten models.
TRIVIALITY BOUND OF LINEAR σ-MODEL WITH FINITE PION MASS
Authors: KIMURA K. , SANDA A.I. , SUGIYAMA Y.
Published: November 2004

We study the triviality bound of ϕ4-theory with explicit breaking terms. To do this the scaling behavior of this model is investigated by using perturbative method and nonperturbative method. The results obtained in this calculation are applied to pion physics and the bound of mσ is estimated. There is a possibility that the bound of mσ increases from 400 MeV to 530 MeV by explicit breaking terms.
EFFECTIVE POTENTIALS FOR ϕ4-THEORY IN 2+1 DIMENSIONS
Authors: OLSEN R.A. , RAVNDAL F.
Published: November 2004

Spontaneous symmetry breaking in ϕ4-theory in 2+1 dimensions is investigated using the Gaussian approximation. The theory stays in the symmetric phase at zero temperature as long as the bare coupling constant is below a critical value λc. When λ>λc the symmetric phase is again stable when the temperature is above a transition temperature T(λ). The obtained results are compared with the predictions of the standard one-loop effective potential.
VIRIAL COEFFICIENTS FOR AN ANYON GAS IN A STRONG MAGNETIC FIELD
Authors: MYUNG YUN SOO , YI SANG HOON , JUE CHANGKEUN
Published: November 2004

We discuss the virial coefficients for a gas of anyons in the strong magnetic field at the low temperature.
RESTRICTIONS ON THE HYPOTHETICAL LONG RANGE INTERACTIONS FROM THE CASIMIR-TYPE NULL EXPERIMENT WITH THREE TEST BODIES
Authors: BORDAG M. , MOSTEPANENKO V. M. , YU. SOKOLOV I.
Published: November 2004

A realistic null experiment is suggested in which the Casimir force between a plane plate and a spherical lens is compensated by the force of gravitational attraction. This configuration is shown to be very sensitive to the existence of additional hypothetical forces of Yukawa-type or power laws. From the suggested null experiment the restrictions on the Yukawa constant α can be strengthened by a factor up to 1000 in a wide range 10−8 m < λ < 10−4 m and by a factor of 10 for λ from several centimeters to several meters. For power law interactions the strengthening of restrictions by a factor of 20 is possible for the force decreasing as r−5.
ON THE POSSIBILITY OF LOW MASS QUARK DROPLET STARS
Authors: CHAKRABARTY SOMENATH
Published: November 2004

The possibility of stable quark-droplet stars is investigated using dynamical density dependent quark mass model of confinement. Some of its gross properties has also been studied.
TEMPORAL DESCRIPTION OF INTERFERENCE PHENOMENA IN NUCLEAR REACTIONS WITH TWO-PARTICLE CHANNELS
Authors: EREMIN N. V. , GIARDINA G. , OLKHOVSKY V. S. , OMELCHENKO S. A.
Published: November 2004

A self-consistent space-time analysis (made in the laboratory system) of the interference between non-resonant (prompt) and resonant (delayed) processes in nuclear reactions with two-particle channels, leads to a generalization of the expressions obtained (in the center-mass system) in the framework of an almost stationary formalism. The role of a new phase parameter φ, which describes the space-time shifts between the sources of the final-particle emission caused by the motion in the laboratory system of the decaying compound-nucleus, is analyzed. We find that in many realistic cases (when φ ~ 1) the effect related to this motion produces noticeable changes in the cross-sections.