bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of an agri‐environment scheme option: seed‐bearing crops for farmland birds
Authors: STOATE CHRIS , HENDERSON IAN G. , PARISH DAVID M. B.
Published: November 2004

Winter mortality, resulting from reduced food supply during a period of agricultural intensification, is thought to have driven population declines for some farmland bird species. Planting of game crops has increased over this period in order to provide food and cover for gamebirds. We investigate the potential of this managed habitat for farmland songbird conservation, using intensive single‐site studies, and an extensive national survey. Game crops were used more than other farmland habitats by a wide range of bird species. Kale and quinoa were used by many species, whereas maize was used by very few. Cereals such as triticale and millet were used by many species, including several not associated with brassicas such as kale. Crop species differed in the rate of seed shedding, and therefore in the amount of seed food that they provided through the winter. Crop location influenced use by some bird species, with crops close to hedges or other cover generally being favoured. Use of nitrogen fertilizer influenced seed yield, and therefore crop value as a source of food for birds. Our results suggest that, if managed and sited correctly, a combination of two or three crop species can provide a valuable winter food resource for many nationally declining farmland bird species, but further attention needs to be given to their agronomy. This form of management is now incorporated as an option within agri‐environment schemes in England, Scotland and Wales. It enables farmers to apply existing skills to conservation and is compatible with their cultural values.
The effects of habitat structure on predation risk of birds in agricultural landscapes
Authors: WHITTINGHAM MARK J. , EVANS KARL L.
Published: November 2004

It has been suggested that increased predation rates may rival habitat alteration as a causal agent in farmland bird population declines. Such a view may be over‐simplistic, however, as changes in habitat structure may influence habitat selection and foraging efficiency through their influence on perceived and actual predation risk. We review evidence from the literature on the effects of habitat structure on predation risk of foraging and nesting birds and apply these principles to investigate the likely effects on the 20 species that comprise the UK Government's ‘Farmland Bird Index’. Shorter vegetation is likely to enhance foraging efficiency and reduce predation risk (when ground foraging) for 15 of the 20 species. However, within grassland systems longer vegetation is known to enhance food supplies (e.g. Tipulid larvae and voles) of several farmland bird species and so mosaics of short and long vegetation may provide the optimum conditions for most species (e.g. LapwingVanellus vanellus, StarlingSturnus vulgaris, Barn OwlTyto alba). Agricultural intensification has encouraged uniform dense swards, thus reducing habitat diversity, and agri‐environment schemes that provide heterogeneous sward structure may thus facilitate farmland bird conservation. Intensification has also resulted in less dense hedgerows; although a reversal of this trend may improve foraging efficiency for many species, it may be detrimental to a smaller number of species that prefer shorter, less dense hedges for nesting. Before these tentative conclusions can be confirmed, more research is required that considers how the effects of habitat structure on individuals is likely to translate into population‐level impacts.
EVAPORITES OF THE WADI NATRUN: SEASONAL AND ANNUAL VARIATION AND ITS IMPLICATION FOR ANCIENT EXPLOITATION*
Authors: SHORTLAND A. J.
Published: November 2004

The evaporitic deposits of the Wadi Natrun on the edge of the Western Desert of Egypt have been used in variety of crafts and industries for over 6000 years. This paper reviews the formation processes of the evaporitic deposits between the different lakes in the wadi and for the wadi as a whole. It shows that the precipitation of sodium carbonate minerals within the lakes is seasonal and probably subject to long‐term fluctuation as climate varies. This has a significant impact on the use of the lakes for ancient industries, particularly the manufacture of glass.
CHEMICAL AND MINERALOGICAL CHARACTERIZATION OF SASANIAN AND EARLY ISLAMIC GLAZED CERAMICS FROM THE DEH LURAN PLAIN, SOUTHWESTERN IRAN*
Authors: HILL D. V. , SPEAKMAN R. J. , GLASCOCK M. D.
Published: November 2004

One hundred and seventy‐five glazed ceramics from Sasanian and Early Islamic period sites located on the Deh Luran Plain in southwestern Iran were examined by instrumental neutron activation analysis for characterizing differences in ceramic pastes and by laser‐ablation inductively coupled plasma mass‐spectrometry for identifying the constituents of the ceramic glazes. The results of the analysis reveal that alkaline‐based glazed ceramics have paste compositions that are distinct from contemporary and later ceramics decorated with alkaline–low‐lead and lead‐based glazes.
PIGMENT IDENTIFICATION IN GREEK POTTERY BY RAMAN MICROSPECTROSCOPY*
Authors: PÉREZ J. M. , ESTEVE‐TÉBAR R.
Published: November 2004

Raman microspectroscopy (RMS) is now established as a key technique for the identification of pigments of archaeological pottery that permits the in situ study of art objects by a non‐destructive procedure. The information obtained represents a great aid to restoration and conservation techniques. In this work, the chemical nature of the red, black and white pigments of five samples of Greek pottery from the end of the fifth century and the first half of the fourth century bc, exhumed from the Iberian necropolis of Cabezo Lucero (Guardamar del Segura, Alicante, Spain), has been identified. The black and the red pigments are found to be magnetite (Fe3O4) and hematite (α‐Fe2O3), respectively. The white pigment is found, for the first time, to be composed of alumina (α‐Al2O3 and γ‐Al2O3) probably yielded by the thermal decomposition of Greek bauxite.
DNA AND PROTEIN RECOVERY FROM WASHED EXPERIMENTAL STONE TOOLS*
Authors: SHANKS O. C. , KORNFELD M. , REAM W.
Published: November 2004

Traces of protein and DNA are preserved on stone tools used to process animals. Previous research documents the identification of protein residues from tools sonicated in 5% ammonium hydroxide, but it remains untested whether the same treatment yields useable DNA. In this study we report both DNA and protein recovery using 5% ammonium hydroxide from residues on stone tools. We extracted 13‐year‐old residues from experimentally manufactured stone tools used to butcher a single animal. We also show that surface washing procedures typically used to curate stone tools remove only a small fraction of the DNA and protein deposited during animal butchery.
Modified Method of Characteristics for Simulating Microscale Energy Transport
Authors: Pilon Laurent , Katika Kamal M.
Published: November 2004

This paper presents a new numerical scheme for simulating multidimensional transient and steady-state microscale energy transport. The new method is based on the method of characteristics that follows heat carriers along their pathline. Unlike traditional methods, it uses a fixed computational grid and follows the heat carriers backward in time. The method 1) is accurate, 2) is unconditionally stable, 3) can deal with complex geometries without a large increase in computational cost, and 4) can be used for solving coupled equations using other numerical schemes. First, the numerical scheme is described. Then, simulations for transient and steady-state phonon transport in dielectric thin films are discussed. Numerical results are compared with analytical and reported numerical solutions and good agreement is obtained.
Free Surface Flow in High Speed Fiber Drawing With Large-Diameter Glass Preforms
Authors: Wei Zhiyong , Lee Kok-Meng , Tchikanda Serge W. , Zhou Zhi , Hong Siu-Ping
Published: November 2004

This paper presents a complete two-dimensional (2D) thermofluid model for predicting the neck-down shape in the fiber drawing process. This model uses the controlled draw tension to calculate the Neumann boundary condition at the furnace exit; thus, it does not require specifying the speed (or diameter) of the fiber as most previous studies did. The model presented here can be applied to optimization of the high-speed draw process with large-diameter preforms. In this study, the radiative transfer equation is directly solved for the radiation fluxes using the discrete ordinate method coupled with the solution of the free surface flow, which does not assume that the glass is optically thick and does not neglect the glass absorption at the short-wavelength band. The artificial compressibility method is used to solve the Navier-Stokes equations. A staggered-grid computation scheme that is shown to be efficient and robust was used to reduce the computation load in solving the complete 2D model. The neck-down profile of a large preform (9 cm dia) drawn at a relatively high speed of 25 m/s was experimentally measured. The measured profile well matches that derived numerically. Results also show that the free surface calculated using the Dirichlet boundary condition deviates considerably from the measured profile, particularly near the furnace exit where the actual diameter (and, hence, the speed of the glass) is essentially unknown. Although the difference between the numerical results obtained from the full and semi-2D models was small, this difference could be significant if the location at which the glass converges to 125 μm dia is of interest, especially when the preform has a large diameter drawn at a high speed.
Convection Velocity of Temperature Fluctuations in a Turbulent Flume
Authors: Hetsroni G. , Tiselj and I. , Bergant R. , Mosyak and A. , Pogrebnyak E.
Published: November 2004

A numerical investigation of the temperature field in a turbulent flume is presented. We consider the effect of the Prandtl number on the convection velocity of temperature fluctuations in a turbulent boundary layer, and focus also on the effect of the Prandtl number on the connection between the velocity and the temperature fluctuations. Close to the wall, y+<2, convection velocities of the temperature fluctuations decrease with an increase in the Prandtl number, i.e., the scale dependence becomes significantly important. In the region y+<2 the relation of the convection velocity of the temperature fluctuation to that of the velocity fluctuation may be expressed as UcT+=Ucu+Pr−1/3 and Ucq+=Ucu+Pr−1/2 for isothermal and isoflux wall boundary condition, respectively.
Performance and Optimization Analysis for Fins of Straight Taper With Simultaneous Heat and Mass Transfer
Authors: Kundu B. , Das P. K.
Published: November 2004

An analytical method based on Frobenius power series expansion has been developed for the performance prediction of fully wet fins. Fins of different geometries, namely, longitudinal, annular and spine having both trapezoidal and triangular profiles have been considered. Unlike dry fins, the efficiency and effectiveness of wet fins depend on the fin base temperature and psychrometric condition of the ambient air. A generalized criterion has been derived for the optimization of wet fins having the above geometries. A method for constructing design curves for the optimum fins has also been discussed.
Genetic Dissection of the Light-InduciblecarQRSPromoter Region ofMyxococcus xanthus
Authors: Whitworth David E. , Bryan Samantha J. , Berry Andrew E. , McGowan Simon J. , Hodgson David A.
Published: November 2004

InMyxococcus xanthusphotoprotective carotenoids are produced in response to illumination due to regulated expression of carotenoid biosynthesis genes at two loci. Induction of the carotenogenesis regulon is dependent on expression of thecarQRSoperon. The first gene product of the operon, CarQ, is a sigma factor belonging to the ECF family and is responsible for light-dependent initiation of transcription at thecarQRSpromoter. We defined the minimalcarQRSpromoter as a 145-bp fragment of DNA upstream of thecarQRStranscriptional start site, which includes the promoter for a divergent gene,gufA. In order to elucidate regions with the promoter required for activity, point mutations were introduced into thecarQRSpromoter between positions −151 and 6. While most sequence changes abolishedcarQRSpromoter activity, two changes enhanced promoter activity and two changes caused the mutant promoter to become constitutive and independent of CarQ. The promoter-null point mutations and 6-bp deletion mutations implied that thecarQRSpromoter requires a functionalgufApromoter for transcriptional activity and vice versa. By mapping the extent of the promoter region, identifying sequences important for promoter activity, and highlighting potential topological effects, we provide a foundation for further analysis of thecarQRSpromoter.
Binding of the C-Terminal Domain of the α Subunit of RNA Polymerase to the Phage Mu Middle Promoter
Authors: Ma Ji , Howe Martha M.
Published: November 2004

The C-terminal domain of the α subunit (αCTD) of
Escherichia coli
RNA polymerase is often involved in transcriptional regulation. The αCTD typically stimulates transcription via interactions with promoter UP element DNA and transcriptional activators. DNase I footprinting and gel mobility shift assays were used to look for potential interaction of the αCTD with the phage Mu middle promoter P
m
and its activator protein Mor. Binding of RNA polymerase to P
m
in the presence of Mor resulted in production of a DNase I footprint downstream of Mor due to open complex formation and generation of a second footprint just upstream of the Mor binding site. Generation of the upstream footprint did not require open complex formation and also occurred in reactions in which the αCTD or His-α proteins were substituted for RNA polymerase. In gel mobility shift assays, the formation of a supershifted ternary complex demonstrated that Mor and His-α bind synergistically to P
m
DNA. Gel shift assays with short DNA fragments demonstrated that only the Mor binding site and a single upstream αCTD binding site were required for ternary complex formation. These results suggest that the αCTD plays a role in P
m
transcription by binding to P
m
DNA just upstream from Mor and making protein-protein interactions with Mor that stabilize the binding of both proteins.
The Recombination Genes
addAB
Are Not Restricted to Gram-Positive Bacteria: Genetic Analysis of the Recombination Initiation Enzymes RecF and AddAB in
Rhizobium etli
Authors: Zuñiga-Castillo Jacobo , Romero David , Martínez-Salazar Jaime M.
Published: November 2004

Single-strand gaps (SSGs) and double-strand breaks (DSBs) are the major initiation sites for recombination. In bacteria, the SSGs are repaired by RecFOR, while the DSBs are processed by RecBCD in gram-negative bacteria and AddAB in gram-positive bacteria. Unexpectedly, instead of
recBCD
genes, the
addAB
genes were found in members of the α-proteobacteria group (gram negative). Taking
Rhizobium etli
as a model, the role of
recF
and
addAB
genes in homologous recombination and repair of damaged DNA was evaluated. Inactivation of either
recF
or
addA
provoked strong sensitivity to UV radiation and mitomycin C, while an additive effect was observed in the
recF-addA
mutant. The DSBs generated by nalidixic acid caused low viability only in the
addA
mutant. The recombination frequency of large and small plasmids was reduced in the
recF
mutant (24- and 36-fold, respectively), whereas a slight decrease (threefold) in the
addA
mutant was observed. Moreover, an additive effect (47- and 90-fold, respectively) was observed in the double mutant, but it was not as dramatic as that in a
recA
mutant. Interestingly, the frequency of deletion and Campbell-type recombination was slightly affected in either single or double mutants. These results suggest that another pathway exists that allows plasmid and Campbell-type recombination in the absence of
recF
and
addA
genes.
A DNA Region Recognized by the Nitric Oxide-Responsive Transcriptional Activator NorR Is Conserved in β- and γ-Proteobacteria
Authors: Büsch Andrea , Pohlmann Anne , Friedrich Bärbel , Cramm Rainer
Published: November 2004

The σ
54
-dependent regulator NorR activates transcription of target genes in response to nitric oxide (NO) or NO-generating agents. In
Ralstonia eutropha
H16, NorR activates transcription of the dicistronic
norAB
operon that encodes NorA, a protein of unknown function, and NorB, a nitric oxide reductase. A constitutively activating NorR derivative (NorR′), in which the N-terminal signaling domain was replaced by MalE, specifically bound to the
norAB
upstream region as revealed by gel retardation analysis. Within a 73-bp DNA segment protected by MalE-NorR′ in a DNase I footprint assay, three conserved inverted repeats, GGT-(N
7
)-ACC (where N is any base), that we consider to be NorR-binding boxes were identified. Mutations altering the spacing or the base sequence of these repeats resulted in an 80 to 90% decrease of transcriptional activation by wild-type NorR. Genome database analyses demonstrate that the GT-(N
7
)-AC core of the inverted repeat is found in several proteobacteria upstream of gene loci encoding proteins of nitric oxide metabolism, including nitric oxide reductase (NorB), flavorubredoxin (NorV), NO dioxygenase (Hmp), and hybrid cluster protein (Hcp).
Transferable Antibiotic Resistance Elements in
Haemophilus influenzae
Share a Common Evolutionary Origin with a Diverse Family of Syntenic Genomic Islands
Authors: Mohd-Zain Zaini , Turner Sarah L. , Cerdeño-Tárraga Ana M. , Lilley Andrew K. , Inzana Thomas J. , Duncan A. Jane , Harding Rosalind M. , Hood Derek W. , Peto Timothy E. , Crook Derrick W.
Published: November 2004

Transferable antibiotic resistance in
Haemophilus influenzae
was first detected in the early 1970s. After this, resistance spread rapidly worldwide and was shown to be transferred by a large 40- to 60-kb conjugative element. Bioinformatics analysis of the complete sequence of a typical
H. influenzae
conjugative resistance element, ICE
Hin1056
, revealed the shared evolutionary origin of this element. ICE
Hin1056
has homology to 20 contiguous sequences in the National Center for Biotechnology Information database. Systematic comparison of these homologous sequences resulted in identification of a conserved syntenic genomic island consisting of up to 33 core genes in 16 β- and γ-
Proteobacteria
. These diverse genomic islands shared a common evolutionary origin, insert into tRNA genes, and have diverged widely, with G+C contents ranging from 40 to 70% and amino acid homologies as low as 20 to 25% for shared core genes. These core genes are likely to account for the conjugative transfer of the genomic islands and may even encode autonomous replication. Accessory gene clusters were nestled among the core genes and encode the following diverse major attributes: antibiotic, metal, and antiseptic resistance; degradation of chemicals; type IV secretion systems; two-component signaling systems; Vi antigen capsule synthesis; toxin production; and a wide range of metabolic functions. These related genomic islands include the following well-characterized structures: SPI-7, found in
Salmonella enterica
serovar Typhi; PAP1 or pKLC102, found in
Pseudomonas aeruginosa
; and the
clc
element, found in
Pseudomonas
sp. strain B13. This is the first report of a diverse family of related syntenic genomic islands with a deep evolutionary origin, and our findings challenge the view that genomic islands consist only of independently evolving modules.
Cost effectiveness of a community based exercise programme in over 65 year olds: cluster randomised trial
Authors: Munro James F , Nicholl Jon P , Brazier John E , Davey Rachel , Cochrane Tom
Published: November 2004

Objective:To assess the cost effectiveness of a community based exercise programme as a population wide public health intervention for older adults.

Design:Pragmatic, cluster randomised community intervention trial.

Setting:12 general practices in Sheffield; four randomly selected as intervention populations, and eight as control populations.

Participants:All those aged 65 and over in the least active four fifths of the population responding to a baseline survey. There were 2283 eligible participants from intervention practices and 4137 from control practices.

Intervention:Eligible subjects were invited to free locally held exercise classes, made available for two years.

Main outcome measures:All cause and exercise related cause specific mortality and hospital service use at two years, and health status assessed at baseline, one, and two years using the SF-36. A cost utility analysis was also undertaken.

Results:Twenty six per cent of the eligible intervention practice population attended one or more exercise sessions. There were no significant differences in mortality rates, survival times, or admissions. After adjusting for baseline characteristics, patients in intervention practices had a lower decline in health status, although this reached significance only for the energy dimension and two composite scores (p<0.05). The incremental average QALY gain of 0.011 per person in the intervention population resulted in an incremental cost per QALY ratio of €17 174 (95% CI = €8300 to €87 120).

Conclusions:Despite a low level of adherence to the exercise programme, there were significant gains in health related quality of life. The programme was more cost effective than many existing medical interventions, and would be practical for primary care commissioning agencies to implement.
Post-disaster health effects: strategies for investigation and data collection. Experiences from the Enschede firework disaster: Figure 1
Authors: Roorda J , van Stiphout W A H J , Huijsman-Rubingh R R R
Published: November 2004

Background:Public health policy is increasingly concerned with the care for victims of a disaster. This article describes the design and implementation of an epidemiological study, which seeks to match care services to the specific problems of persons affected by a large scale incident. The study was prompted by the explosion of a firework depot in Enschede, the Netherlands.

Study population:All those directly affected by this incident (residents, emergency services personnel, and people who happened to be in the area at the time), some of whom suffered personal loss or injury. The project investigates both the physical and psychological effects of the disaster, as well as the target group’s subsequent call on healthcare services.

Study design:A questionnaire based follow up survey of those directly affected and an ongoing monitoring of health problems relying on reports from healthcare professionals. The follow up survey started three weeks after the incident and was repeated 18 months and almost four years after the incident. The monitoring is conducted over a four year period by general practitioners, the local mental health services department, occupational health services, and the youth healthcare services department. It provides ongoing information.

Results and Conclusions:The results of the study are regularly discussed with healthcare professionals and policy makers, and are made known to the research participants. The paper also explains the considerations that were made in designing the study to help others making up their research plans when confronted with possible health effects of a disaster.
GENERATION OF ASSOCIATIVE PROCESSES IN A NEURAL NETWORK WITH REALISTIC FEATURES OF ARCHITECTURE AND UNITS
Authors: CARTLING BO
Published: November 2004

A recent neural network model of cortical associative memory incorporating neuronal adaptation by a simplified description of its underlying ionic mechanisms is extended towards more realistic network units and architecture. Excitatory units correspond to groups of adapting pyramidal neurons and inhibitory units to groups of nonadapting interneurons. The network architecture is formed from pairs of one pyramidal and one interneuron unit each with inhibitory connections within and excitatory connections between pairs. The degree of adaptability of the pyramidal units controls the character of the network dynamics. An intermediate adaptability generates limit cycles of transitions between stored patterns and regulates oscillation frequencies in the range of theta rhythms observed in the brain. In particular, neuronal adaptation can impose a direction of transitions between overlapping patterns also in a symmetrically connected network. The model permits a detailed analysis of the transition mechanisms. Temporal sequences of patterns thus formed may constitute parts of associative processes, such as recall of stored sequences or search of pattern subspaces. As a special case, neuronal adaptation can accomplish pattern segmentation by which overlapping patterns are temporally resolved. The type of limit cycles produced by neuronal adaptation may also be of significance for central pattern generators, also for networks involving motor neurons. The applied learning rule of Hebbian type is compared to a modified version also common in neural network modelling. It is also shown that the dependence of the network dynamic behaviour on neuronal adaptability, from fixed point attractors at weak adaptability towards more complex dynamics of limit cycles and chaos at strong adaptability, agrees with that recently observed in a more abstract version of the model. The present description of neuronal adaptation is compared to models based on dynamic firing thresholds.
DYNAMICAL AND COMPLEXITY RESULTS FOR HIGH ORDER NEURAL NETWORKS
Authors: GOLES ERIC , MATAMALA MARTÍN
Published: November 2004

We present dynamical results concerning neural networks with high order arguments. More precisely, we study the family of block-sequential iteration of neural networks with polynomial arguments. In this context, we prove that, under a symmetric hypothesis, the sequential iteration is the only one of this family to converge to fixed points. The other iteration modes present a highly complex dynamical behavior: non-bounded cycles and simulation of arbitrary non-symmetric linear neural network.5 We also study a high order memory iteration scheme which accepts an energy functional and bounded cycles in the size of the memory steps.
OPTIMIZATION DYNAMICS FOR PARTITIONED NEURAL NETWORKS
Authors: TSIOUTSIAS DIMITRIS I. , MJOLSNESS ERIC
Published: November 2004

Given a relaxation-based neural network and a desired partition of the neurons in the network into modules with relatively slow communication between modules, we investigate relaxation dynamics for the resulting partitioned neural network. In particular, we show how the slow inter-module communication channels can be modeled by means of certain transformations of the original objective function which introduce new state variables for the inter-module communication links. We report on a parallel implementation of the resulting relaxation dynamics, for a two-dimensional image segmentation network, using a network of workstations. Experiments demonstrate a functional and efficient parallelization of this neural network algorithm. We also discuss implications for analog hardware implementations of relaxation networks.
SUPERHAMILTONIAN FORMALISM FOR 2D N=1, 2 THEORIES
Authors: IVANOV E. , TOPPAN F.
Published: November 2004

We show how to formulate two-dimensional (2D) supersymmetric N=1, 2 theories, both massive and conformal, within a manifestly supersymmetric Hamiltonian framework, via the introduction of a (super)-Poisson brackets structure defined on superfields. In this approach, as distinct from the previously known superfield Hamiltonian formulations, the dynamics is not separated into two unrelated 2D light-cone superspaces, but is recovered by specifying boundary conditions at a given “super-time” coordinate. So the approach proposed provides a natural generalization of canonical Hamiltonian formalism. One of its interesting features is that the physical and auxiliary fields equations appear on equal footing as the Hamilton ones.
A GENERALIZED DIRAC’S QUANTIZATION CONDITION FOR PHENOMENOLOGICAL NON-ABELIAN MAGNETIC MONOPOLES
Authors: MAIA ADOLFO , RODRIGUES WALDYR A.
Published: November 2004

We extend the Dirac’s quantization condition for the phenomenological non-Abelian magnetic monopoles whose theory was developed in a number of papers in the past few years.
FLOWS FOR RECTANGULAR MATRIX MODELS
Authors: LAFRANCE RENÉ , MYERS ROBERT C.
Published: November 2004

Several new results on the multicritical behavior of rectangular matrix models are presented. We calculate the free energy in the saddle point approximation, and show that at the triple-scaling point, the result is the same as that derived from the recursion formulas. In the triple-scaling limit, we obtain the string equation and a flow equation for arbitrary multicritical points. Parametric solutions are also examined for the limit of almost-square matrix models. This limit is shown to provide an explicit matrix model realization of the scaling equations proposed to describe open-closed string theory.
DILOGARITHM IDENTITIES, FUSION RULES AND STRUCTURE CONSTANTS OF CFTs
Authors: TERHOEVEN MICHAEL
Published: November 2004

Recently dilogarithm identities have made their appearance in the physics literature. These identities seem to allow to calculate structure constants like, in particular, the effective central charge of certain conformal field theories from their fusion rules. In Ref. 12 a proof of identities of this type was given by considering the asymptotics of character functions in the so-called Rogers-Ramanujan sum form and comparing with the asymptotics predicted by modular covariance. Refining the argument, we obtain the general connection of quantum dimensions of certain conformal field theories to the arguments of the dilogarithm function in the identities in question and an infinite set of consistency conditions on the parameters of Rogers-Ramanujan type partitions for them to be modular covariant.
CP VIOLATION IN HIGGS DECAYS
Authors: HE XIAO-GANG , MA J.P. , McKELLAR BRUCE
Published: November 2004

We study CP violation in fermion pair decays of Higgs boson. We identify some CP odd observables related to the tree level decay amplitude. We find that a few thousands Higgs boson decay events can already provide important information about CP violation. If the Higgs boson is produced, such an analysis could be carried out at the SSC, LHC and NLC.
PION DECAY CONSTANT AND THE GELL-MANN-OAKES-RENNER RELATION IN NUCLEI
Authors: CHANFRAY G. , ERICSON M. , KIRCHBACH M.
Published: November 2004

We study the pion decay constant, associated with the time component of the axial current, in the nuclear medium in terms of the pion self-energy. The theoretical scheme exploits chiral properties of the s-wave πN amplitude as previously applied to the study of the medium renormalized pion mass. We show that the Gell-Mann-Oakes-Renner relation holds to a good approximation in the medium. The renormalizations of the pion decay constant and the pion mass are consistent with that predicted for the quark condensate in the medium.
GAUGING OF T-DUALITY INVARIANT WORLDSHEET STRING ACTIONS
Authors: KUMAR ALOK
Published: November 2004

T-duality invariant worldsheet string actions, recently written down by Schwarz and Sen, are coupled to the worldsheet gauge fields. It is shown that the integration of the dual coordinates gives the conventional, vector, axial and chiral, gauged string actions for the appropriate choice of the gauged isometries. Alternatively, the gauge field integration is shown to give a T-duality invariant action which matches with the corresponding results known earlier.
RG-IMPROVED BOUNDS ON HIGGS BOSON AND TOP QUARK MASSES FROM ELECTROWEAK BARYOGENESIS
Authors: MAJUMDAR A.S. , SETHI S.K. , MAHAJAN S. , MUKHERJEE A. , PANCHAPAKESAN N. , SAXENA R.P.
Published: November 2004

Electroweak baryogenesis in a single Higgs doublet model is considered. A renormalization group-improved effective potential is used. The requirement that the created baryon asymmetry is not washed out leads to bounds on the Higgs mass which vary significantly with the top quark mass.
NON-SINGULAR CONSTANT CURVATURE TWO-DIMENSIONAL BLACK HOLE
Authors: LEMOS JOSÉ P. S. , SÁ PAULO M.
Published: November 2004

We show that the constant curvature two-dimensional theory of Teitelboim and Jackiw admits a black hole solution, which is free of space-time singularities. The maximally extended space-time consists of an infinite chain of universes connected by timelike wormholes.
A COVARIANT FORMULATION OF CLASSICAL SPINNING PARTICLE
Authors: CHO JIN-HO , KIM JAE-KWAN , HYUN SEUNGJOON
Published: November 2004

Covariantly we reformulate the description of a spinning particle in terms of the Poincaré group. We also construct a Lagrangian which entails all possible constraints explicitly; all constraints can be obtained just from the Lagrangian. Furthermore, in this covariant reformulation, the Lorentz element is to be considered to evolve the momentum or spin component from an arbitrary fixed frame and not just from the particle rest frame. Our system which is different from the usual formulation is directly comparable with the pseudoclassical formulation. We get a peculiar symmetry which resembles the supersymmetry of the pseudoclassical formulation.
INDUCED θ-TERM IN NAMBU-JONA-LASINIO MODEL AT FINITE TEMPERATURES
Authors: HO CHOON-LIN , HU BAMBI , YU HOI-LAI
Published: November 2004

We have studied the induced topological θ-term in the Nambu-Jona-Lasinio model at finite temperatures. It is found that it vanishes at the same critical temperature at which chiral symmetry is restored. This shows that hidden local symmetry works even at finite temperatures.
CP-VIOLATION IN THE $\bar tt$-SYSTEM IN MODELS WITH SPONTANEOUS SYMMETRY BREAKING
Authors: DECKER R. , KRAUSE B.
Published: November 2004

In the framework of models with spontaneous CP-violation we compute at the one-loop level the CP-violating form factors which occur in the [Formula: see text]-production in e− + e+ annihilation.
MODULI SPACE OF TOPOLOGICAL TWO-FORM GRAVITY
Authors: ABE MITSUKO , NAKAMICHI AKIKA , UENO TATSUYA
Published: November 2004

We propose a topological version of four-dimensional (Euclidean) Einstein gravity, in which anti-self-dual two-forms and an SU(2) connection are used as fundamental fields. The theory describes the moduli space of conformally self-dual Einstein manifolds. In the presence of a cosmological constant, we evaluate the index of the elliptic complex associated with the moduli space.
ANYONIC CONSTRUCTION OF THE slq,s(2) ALGEBRA
Authors: MATHEUS-VALLE J. L. , MONTEIRO M. R.
Published: November 2004

By considering anyonic oscillators in a two-dimensional lattice, we realize the quantum semigroup sl q,s(2) by means of a generalized Schwinger construction. We find that the parameter q of the algebra is connected to the statistical parameter, whereas the s parameter is related to how angles are measured in this two-dimensional lattice.
THE U(3) × U(3) NAMBU-JONA-LASINIO MODEL WITH THE GLUON CONDENSATE AND AXIAL ANOMALY AT FINITE TEMPERATURE
Authors: KALINOVSKY YU. L. , VOLKOV M. K.
Published: November 2004

The U (3) × U (3) Nambu-Jona-Lasinio model with the gluon condensate and axial anomaly ('t Hooft determinant) is investigated at finite temperature. We study the behavior of the constituent quark masses, quark condensates, meson masses, coupling constants as functions of the temperature. It is shown that the gluon condensate plays a stabilizing role for behavior of physical quantities when temperature changes. This influence is more visible for the light quarks (up and down). The axial anomaly and the mixing angle (η, η′) decrease when the temperature increases.
MODULAR SYMMETRIES IN ZN ORBIFOLD COMPACTIFIED STRING THEORIES WITH WILSON LINES
Authors: BAILIN D. , LOVE A. , SABRA W.A. , THOMAS S.
Published: November 2004

Target space modular symmetries relevant to string loop threshold corrections are studied for ZN orbifold compactified string theories containing Wilson line background fields.
A MODEL STUDY OF NUCLEAR STRUCTURE FUNCTIONS
Authors: GONZÁLEZ P. , VENTO V. , TRAINI M. , ZAMBARDA A.
Published: November 2004

We calculate the structure function for a deuteron using the hadronic quark cluster decomposition. By assuming that nuclei might be composed of quasi deuterons, we study their structure functions. The procedure enables a quantum mechanical parametrization of various scenarios, among them nuclear dynamics and nucleon swelling. Moreover it is specially suited to study quark exchange effects. We show, within a scheme where perturbative evolution effects are minimized, that the region around x=1 is very sensitive to these two mechanisms and their effects can be disentangled.
THE q2 DEPENDENCE OF W AND Z COUPLING CONSTANTS IN THE INTERVAL $ \le \left| {q^2 } \right| \le m_Z^2 $
Authors: NOVIKOV V.A. , OKUN L.B. , VYSOTSKY M.I.
Published: November 2004

The gauge coupling constants of W and Z bosons, αW and αZ, are not running unless [Formula: see text] Their dependence on q2 is given by simple expressions and is very weak in the interval [Formula: see text] compared to that of the photon.
FLAVOR CHANGING NEUTRAL CURRENTS IN SU(3)L⊗U(1)Y MODELS
Authors: DUMM D. GÓMEZ , PISANO F. , PLEITEZ V.
Published: November 2004

We consider flavor changing neutral current effects coming from the Z′ exchange in 3–3–1 models. We show that the mass of this extra neutral vector boson may be less than 2 TeV and discuss the problem of quark family discrimination.
THE HIGGS MODEL FOR ANYONS AND LIOUVILLE ACTION: CHAOTIC SPECTRUM, ENERGY GAP AND EXCLUSION PRINCIPLE
Authors: MATONE MARCO
Published: November 2004

The requirements of geodesic completeness and self-adjointness imply that the Hamiltonian for anyons is the Laplacian with respect to the Weil-Petersson metric. This metric is complete on the Deligne-Mumford compactification of moduli (configuration) space. The structure of this compactification fixes the possible anyon configurations. This allows us to identify anyons with singularities (elliptic points with ramification q−1) in the Poincare metric implying that anyon spectrum is chaotic for n≥3. Furthermore, the bound on the holomorphic sectional curvature of moduli spaces implies a gap in the energy spectrum. For q=0 (punctures) anyons are infinitely separated in the Poincare metric (hard core). This indicates that the exclusion principle has a geometrical interpretation. Finally we give the differential equation satisfied by the generating function for volumes of the configuration space of anyons.
ρ PARAMETER IN THE VECTOR CONDENSATE MODEL OF ELECTROWEAK INTERACTIONS
Authors: CYNOLTER G. , LENDVAI E. , POCSIK G.
Published: November 2004

In the standard model of electroweak interactions the Higgs doublet is replaced by a doublet of vector bosons and the gauge symmetry is broken dynamically. This generates masses for the gauge bosons and fermions as well as it fixes the interactions in the model. The model has a low momentum scale. In this note we show that the model survives the test of the ρ parameter, and to each momentum scale ρ chooses a possible range of vector boson masses.
LONG DISTANCE UNIVERSALITY OF LAUGHLIN STATE AND CALOGERO-SUTHERLAND MODEL
Authors: ISO SATOSHI
Published: November 2004

We study the universal long distance behavior of the Laughlin state for the fractional quantum Hall effect and the ground state of the Calogero-Sutherland model (one-dimensional 1/r2 interaction model). In particular, it is shown that these two wave functions coincide exactly when Laughlin state is confined in a narrow cylinder geometry. The seeming difference of dimensionality is merely a difference of representation of wave functions. We also give a recipe to interpret operators acting on states in the lowest Landau level in terms of the usual one-dimensional fermion operators, which is important for extracting the Tomonaga-Luttinger liquid behavior of the edge states.
BV AND BFV FORMULATION OF A GAUGE THEORY OF QUADRATIC LIE ALGEBRAS IN 2D AND A CONSTRUCTION OF W3 TOPOLOGICAL GRAVITY
Authors: DAYI ÖMER F.
Published: November 2004

The recently proposed generalized field method for solving the master equation of Batalin and Vilkovisky is applied to a gauge theory of quadratic Lie algebras in two dimensions. The charge corresponding to BRST symmetry derived from this solution in terms of the phase space variables by using the Noether procedure, and the one found due to the BFV-method are compared and found to coincide. W3-algebra, formulated in terms of a continuous variable is exploit in the mentioned gauge theory to construct a W3 topological gravity. Moreover, its gauge fixing is briefly discussed.
RADIATIVE EFFECTS IN A CONSTANT MAGNETIC FIELD USING THE QUANTUM MECHANICAL PATH-INTEGRAL
Authors: MCKEON D.G.C. , SHERRY T.N.
Published: November 2004

It has been shown how evaluation of matrix elements of the form  using the quantum mechanical path-integral allows one to determine radiative corrections in quantum field theory without encountering loop momentum integrals. In this paper we show how this technique can be applied when there is a constant background magnetic field contributing to the “Hamiltonian” H.
UNSTABLE NONLINEAR SCHRÖDINGER EQUATION — A DRINFEL’D-SOKOLOV APPROACH AND BI-HAMILTONIAN STRUCTURE
Authors: CHOWDHURY A. ROY , MUKHOPADHYAY I.
Published: November 2004

The unstable nonlinear Schrödinger equation is derived in the formalism of Drinfel’d-Sokolov. It is observed that the required reduction of the independent set of nonlinear field variables is automatic. Bi-Hamiltonian structure is deduced with the help of the master symmetry.
FOUR-DIMENSIONAL YANG-MILLS THEORY IN LOCAL GAUGE INVARIANT VARIABLES
Authors: LUNEV F.A.
Published: November 2004

The general method that allows to formulate 4-D SU(N) Yang-Mills theory in terms of only local gauge invariant variables is presented. For the case N=2, that is discussed in details, this gauge invariant formulation appears to be very similar to R2-gravity.
LOOP INTEGRALS, ℛ-FUNCTIONS AND THEIR ANALYTIC CONTINUATION
Authors: BRÜCHER L. , FRANZKOWSKI J. , KREIMER D.
Published: November 2004

To determine entirely the resulting functions of one-loop integrals it is necessary to find the correct analytic continuation to all relevant kinematical regions. We argue that this continuation procedure may be performed in a general and mathematical accurate way by using the ℛ-function notation of these integrals. The two- and three-point cases are discussed explicitly in this manner.
SUPERSYMMETRIC DESCRIPTION OF SPIN-ONE PARTICLES AS A TOPOLOGICAL MODEL
Authors: ATTAL ROMAIN , BAULIEU LAURENT
Published: November 2004

We identify the locally N=2 supersymmetric Lagrangian describing spin-one particles in a D-dimensional space-time as the gauge-fixing of a topological quantum mechanical model acting in a target-space with two extra dimensions.
WHY IS THE δ(983)→2γ WIDTH SO SMALL?
Authors: DEAKIN A.S. , ELIAS V. , MCKEON D.G.C. , SCADRON M.D. , BRAMON A.
Published: November 2004

The δ0(983)→2γ decay width is calculated in a linear σ-model framework, in which both quark and meson loops contribute to the decay amplitude, and compared to the experimental decay width. The result is seen to depend strongly on the magnitude of the light quark mass and is compatible with the present measured rate, up to experimental uncertainties, for quark masses of order 300 MeV.
TOPOLOGICAL CONFORMAL FIELD THEORY WITH A RATIONAL W POTENTIAL AND THE DISPERSIONLESS KP HIERARCHY
Authors: AOYAMA S. , KODAMA Y.
Published: November 2004

We present a new class of topological conformal field theories (TCFTs) characterized by a rational W potential, which includes the minimal models of A and D types as its subclasses. An explicit form of the W potential is found by solving the underlying dispersionless KP hierarchy in a particular small phase space. We also discuss the dispersionless KP hierarchy in large phase spaces by reformulating the hierarchy, and show that the W potential takes a universal form, which does not depend on a specific form of the solution in a large space.
Z2 GAUGE MATTER COUPLED TO 4-D SIMPLICIAL QUANTUM GRAVITY
Authors: AMBJØRN J. , JURKIEWICZ J. , BILKE S. , BURDA Z. , PETERSSON B.
Published: November 2004

Employing Monte-Carlo simulation we study the phase diagram of a Z2 gauge field coupled to simplicial quantum gravity. We localize a critical point of the model where both the matter and gravity sectors have a second order phase transition. We found the value of the critical index γg=0.16(4) of the gravity susceptibility at the critical point.
REALIZATION OF W1+∞ AND VIRASORO ALGEBRAS IN SUPERSYMMETRIC THEORIES ON FOUR MANIFOLDS
Authors: JOHANSEN ANDREI
Published: November 2004

We demonstrate that a supersymmetric theory twisted on a Kähler four-manifold M= Σ1×Σ2, where Σ1,2 are 2-D Riemann surfaces, possesses a “left-moving” conformal stress tensor on Σ1 (Σ2) in the BRST cohomology. The central charge of the Virasoro algebra has a purely geometric origin and is proportional to the Euler characteristic of the Σ2 (Σ1) surface. This structure is shown to be invariant under renormalization group. We also give a representation of the algebra W1+∞ in terms of a free chiral supermultiplet.
CLOSING THE UNIVERSE BY RELAXING THE COSMOLOGICAL CONSTANT
Authors: LOPEZ JORGE L. , NANOPOULOS D. V.
Published: November 2004

We consider a string-inspired no-scale SU (5) × U (1) supergravity model. In this model there is a negative contribution to the vacuum energy, which may be suitably canceled by a positive contribution typically present in string theory. One may then end up with a vacuum energy which brings many cosmological observations into better agreement with theoretical expectations, and a fixed value for the present abundance of neutralinos. We delineate the regions of parameter space allowed in this scenario, and study the ensuing predictions for the sparticle and Higgs-boson masses in this model.
ONE-LOOP EFFECTIVE POTENTIAL IN 2-D DILATON GRAVITY ON HYPERBOLIC PLANE
Authors: KIRSTEN K. , ODINTSOV S. D.
Published: November 2004

The one-loop effective potential in 2-D dilaton gravity in conformal gauge on the topologically non-trivial plane ℝ × S1 and on the hyperbolic plane H2/Γ is calculated. For arbitrary choice of the tree scalar potential it is shown that the one-loop effective potential explicitly depends on the reference metric (through the dependence on the radius of the torus or the radius of H2/Γ). This phenomenon is absent only for some special choice of the tree scalar potential corresponding to the Liouville potential and leading to one-loop uv finite theory. The effective equations are also discussed.
MASSIVE PARTICLE CREATION IN A STATIC (1 + 1)-DIMENSIONAL SPACE-TIME
Authors: LAMB D. J. , CAPRI A. Z. , ROY S. M.
Published: November 2004

We show explicitly that there is particle creation in a static space-time. This is done by studying the field in a coordinate system based on a physical principle which has recently been proposed. There the field is quantized by decomposing it into positive and negative frequency modes on a particular space-like surface. This decomposition depends explicitly on the surface where the decomposition is performed, so that an observer who travels from one surface to another will observe particle production due to the different vacuum state.
QUANTUM RIEMANN SURFACES, 2-D GRAVITY AND THE GEOMETRICAL ORIGIN OF MINIMAL MODELS
Authors: MATONE MARCO
Published: November 2004

Based on a recent paper by Takhtajan, we propose a formulation of 2-D quantum gravity whose basic object is the Liouville action on the Riemann sphere Σ0, m+n with both parabolic and elliptic points. The identification of the classical limit of the conformal Ward identity with the Fuchsian projective connection on Σ0, m+n implies a relation between conformal weights and ramification indices. This formulation works for arbitrary d and admits a standard representation only for d ≤ 1. Furthermore, it turns out that the integerness of the ramification number constrains d = 1 − 24/(n2 − 1) that for n = 2m + 1 coincides with the unitary minimal series of CFT.