bluuebunny/crossref_metadata_2025 huggingface dataset:
Dirac-type approach for consistent discretizations of classical constrained theories
Authors: Di Bartolo Cayetano , Gambini Rodolfo , Porto Rafael A. , Pullin Jorge
Published: December 2004

We analyze the canonical treatment of classical constrained mechanical systems formulated with a discrete time. We prove that under very general conditions, it is possible to introduce nonsingular canonical transformations that preserve the constraint surface and the Poisson or Dirac bracket structure. The conditions for the preservation of the constraints are more stringent than in the continuous case and as a consequence some of the continuum constraints become second class upon discretization and need to be solved by fixing their associated Lagrange multipliers. The gauge invariance of the discrete theory is encoded in a set of arbitrary functions that appear in the generating function of the evolution equations. The resulting scheme is general enough to accommodate the treatment of field theories on the lattice. This paper attempts to clarify and put on sounder footing a discretization technique that has already been used to treat a variety of systems, including Yang–Mills theories, BF theory, and general relativity on the lattice.
On chaotic behavior of gravitating stellar shells
Authors: Barkov M. V. , Bisnovatyi-Kogan G. S. , Neishtadt A. I. , Belinski V. A.
Published: December 2004

Motion of two gravitating spherical stellar shells around a massive central body is considered. Each shell consists of point particles with the same specific angular momenta and energies. In the case when one can neglect the influence of gravitation of one (“light”) shell onto another (“heavy”) shell (“restricted problem”) the structure of the phase space is described. The scaling laws for the measure of the domain of chaotic motion and for the minimal energy of the light shell sufficient for its escape to infinity are obtained.
Effects of static contact angles on inviscid gravity-capillary waves
Authors: Nicolás José A.
Published: December 2004

The effects of a static contact angle θ0 on the natural frequencies of inviscid gravity-capillary waves depend on the contact-line conditions. The cases of free-end and pinned-end edge conditions are analyzed in the limit of large Bond number B. The ratio (ω2−ω02)∕ω02 (where ω0 and ω are the natural frequencies without and with meniscus, respectively) is proportional to B−1 or B−1 in the case of fixed contact angle or fixed contact line, respectively, and then the effect of the meniscus is greater for pinned-end edges than for free-end ones. When the contact angle is fixed (and for circular cylinders of aspect ratio not small) the natural frequency ω increases with increasing contact angle. When the contact line is fixed the natural frequency ω is smaller than ω0 in both cases of hydrophilic (θ0<π∕2) and hydrophobic surfaces (θ0>π∕2). It is shown that the reduction in frequency due to the meniscus can exceed the reduction associated with viscous effects. The results of this work compare better with experimental measurements, than those reported in the literature previously.
Automated system for x-ray absorption spectroscopy of nanoparticle nucleation and growth
Authors: Calvin S. , Carpenter E. E. , Cestone V. , Kurihara L. K. , Harris V. G. , Brown E. C.
Published: December 2004

X-ray absorption spectroscopy (XAS) is a useful tool for studying nanoparticle synthesis and growth. Described here is a system for automating synthesis and data collection, allowing time-resolved XAS measurements at a synchrotron to be accurately combined with measurements made under identical conditions elsewhere, and promising the ability to use XAS with experiments in combinatorial chemistry. The primary components of this system are a commercial parallel processor and a custom flow cell. The system has been used to collect data on the synthesis of iron oxides from iron(II) acetylacetonate.
Light-transmission aggregometer using a vibration-induced disaggregation mechanism
Authors: Shin S. , Jang J. H. , Park M. S. , Ku Y. H. , Suh J. S.
Published: December 2004

The vibration-induced disaggregation technique of red blood cell (RBC) aggregates has been applied to design a new light-transmission aggregometer for measurement of aggregation index. For disaggregation of RBCs, the rotational shear flow in the Couette system is replaced with a simple low-frequency vibration in a disposable cavity slide glass. Using a vibration generator, one can disaggregate the RBC aggregates stored in the cavity slide glass. After applying the vibration for a specified duration, RBCs tend to reaggregate and instantaneous light-transmittance intensity is measured over time. A syllectogram (the transmitted light intensity versus time) consists of an initial decrease caused by the vibration-induced disaggregation, immediately followed by an increase in the light intensity due to RBC aggregation. The indices of aggregation are determined from the syllectogram using a curve-fitting program. The noble feature of this design is the vibration-induced disaggregation mechanism, which enables to incorporate disposable element that holds the blood sample.
Low-cost and easy experiment to study the electromechanical resonance of piezoelectric ceramics
Authors: Santana-Gil A. , Peláiz-Barranco A. , Rodríguez-López L.
Published: December 2004

An easy and low-cost experiment is presented to characterize the electromechanical resonance of piezoelectric ceramics. By using virtual instrumentation two instruments are substituted simultaneously: an oscilloscope and a frequency-meter. This is accomplished by using a personal computer, a data acquisition card and LabVIEW as programming environment. The experiment has been developed as a contribution to improve the researchers on piezoelectric ceramics, allowing a better analysis of the resonance phenomenon, as compared with the previous experiment, because it is possible to obtain the frequency dependence of the piezoresponse of the samples. The results for a piezoelectric ceramic are presented to validate the new technique, showing suitable properties of the material for piezoelectric applications.
Investigation of time-dependent forces on a nano-Newton-second impulse balance
Authors: D’Souza Brian C. , Ketsdever Andrew D.
Published: December 2004

A torsional impulse balance has been developed as a new diagnostic tool to study fundamental physical processes in micropropulsion systems and laser–surface interactions. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as several nano-Newton-seconds. The behavior of the impulse balance was thoroughly studied and characterized. A simple analytical model of the balance’s motion was developed from the general equation of motion of an underdamped, harmonically oscillating system. Also, two distinct methods of analyzing the experimental data from the nano-impulse balance have been investigated. The first method resolves the total impulse as a function of the balance’s maximum deflection. The second method enables the determination of the impulse and/or force applied as a function of time from the balance’s time-resolved motion. A calibration scheme employing electrostatic actuation techniques is used to experimentally validate the model and impulse measurement techniques.
Identification of microsatellite markers associated with the cereal cyst nematode resistance gene Cre3 in wheat
Authors: Martin E. M. , Eastwood R. F. , Ogbonnaya F. C.
Published: December 2004

Cereal cyst nematode (CCN) is a root disease caused by the pathogen Heterodera avenae Woll. that significantly reduces wheat (Triticum aestivum L.) grain yields in temperate countries. The Cre3 gene, located on chromosome 2DL, provides high levels of resistance to the Australian pathotype and isolates from Syria and Algeria, and has become available to wheat breeders. Selection for lines carrying the Cre3 gene in Australian wheat breeding programs is currently based on a dominant PCR marker (Cre3spf/r) diagnostic for the Cre3 gene. However, this marker has limitations that increase the cost and reduce selection efficiency in screening early-generation breeding lines. Such limitations would be minimised by the identification of a microsatellite marker linked to the Cre3 gene. We have constructed 2 genetic linkage maps of wheat chromosome 2DL and identified microsatellite markers mapping closely to the diagnostic Cre3spf/r marker. These closely linked markers were validated in a diverse range of germplasm, and one microsatellite marker, Xgwm301, which mapped 4 cM from Cre3spf/r, was shown to be highly associated with the presence of the Cre3 gene. Amplification conditions for the Xgwm301 locus were optimised, and its use in marker-assisted selection to identify Cre3 CCN-resistant wheat in the Australian Grain Technologies breeding program is demonstrated.
A Density Functional Theory Study of the Iron-Binding Site of Human Serum Transferrin
Authors: Rinaldo David , Field Martin J.
Published: December 2004

Human serum transferrin binds ferric ions with high affinity in the blood stream and releases them into cells by a process involving receptor-mediated endocytosis and a decrease in pH. The iron-release mechanism is unclear but protonation events and conformational changes are known to be important. In this study, we investigate properties of the iron-binding site theoretically. Our results suggest that an equatorial histidine could be in its histidinate form when bound to iron at neutral and high pH and that protonation of an axial tyrosine is a key event in iron release. Support for this mechanism from other metal-binding enzymes is also presented.
Infrared Spectroscopy of Solvation and Isomers in Fe+(H2O)1,2Arm Complexes
Authors: Walters Richard S. , Duncan Michael A.
Published: December 2004

Vibrational spectroscopy in the OH-stretching region is reported for the mass-selected ion–molecule complexes Fe+(H2O)Ar2 and Fe+(H2O)2Ar. These species are produced by laser vaporization in a pulsed nozzle cluster source, mass-selected with a reflectron time-of-flight mass spectrometer, and studied with infrared laser photodissociation spectroscopy. To achieve efficient photodissociation, the pure metal–water complexes are ‘tagged’ with weakly bound argon atoms. Such tagging is expected to exert a minor perturbation on the spectroscopy. However, we find that this may not be true depending on the binding site. The symmetric stretch and asymmetric stretch of water in these complexes shifts 30–50 cm−1 to the red as a result of binding to the metal cation, and an additional redshift is found for isomers with argon bound to the OH of water. The relationships between isomers and infrared spectra are discussed.
Quantum Monte Carlo Study of Water Molecule: A Preliminary Investigation
Authors: Benedek Nicole A. , Yarovsky Irene , Latham Kay , Snook Ian K.
Published: December 2004

The Quantum Monte Carlo (QMC) technique[1] offers advantages of good scaling with system size (number of electrons) and an ability to uniformly recover over 90% of the electron correlation energy, compared to the more conventional quantum chemistry approaches. For the water molecule in its ground state, it has been shown[2] that the QMC method gives results that are comparable in accuracy to those obtained by the best available conventional methods, while at the same time using much more modest basis sets than is necessary with these methods. Furthermore, the effect of the orbitals needed for these QMC calculations (which may be obtained from either Hartree–Fock or Density Functional Theory) has been investigated. Both the advantages and disadvantages of the QMC method are discussed.
The Native Reaction Centre of Photosystem II: A New Paradigm for P680
Authors: Hughes Joseph L. , Prince Barry J. , Peterson Årsköld Sindra , Smith Paul J. , Pace Ron J. , Riesen Hans , Krausz Elmars
Published: December 2004

Low-temperature spectra of fully active (oxygen-evolving) Photosystem II (PSII) cores prepared from spinach exhibit well developed structure. Spectra of isolated sub-fragments of PSII cores establish that the native reaction centre is better structured and red-shifted compared to the isolated reaction centre. Laser illumination of PSII cores leads to efficient and deep spectral hole-burning. Measurements of homogeneous hole-widths establish excited-state lifetimes in the 40–300 ps range. The high hole-burning efficiency is attributed to charge separation of P680 in native PSII that follows reaction-centre excitation via ‘slow transfer’ states in the inner light-harvesting assemblies CP43 and CP47. The ‘slow transfer’ state in CP47 and that in CP43 can be distinguished in the hole-burning action spectrum and high-resolution hole-burning spectra. An important observation is that 685–700 nm illumination gives rise to efficient P680 charge separation, as established by QA− formation. This leads to a new paradigm for P680. The charge-separating state has surprisingly weak absorption and extends to 700 nm.
An Assessment of Theoretical Protocols for Calculation of the pKa Values of the Prototype Imidazolium Cation
Authors: Magill Alison M. , Yates Brian F.
Published: December 2004

The highly accurate complete basis set method CBS-QB3 has been used in conjunction with the conductor-like polarized continuum (CPCM) method to predict the aqueous pKa values for the three different hydrogen atoms in the imidazolium cation. Excellent agreement was obtained with the available experimental values. The pKa for the deprotonation of imidazole was also calculated and found to be quite different from the experimental estimate. The protocol for the pKa calculation was carefully analyzed and some recommendations made about the choice of levels of theory.
Quantitative metabolic profiling by 1-dimensional 1H-NMR analyses: application to plant genetics and functional genomics
Authors: Moing Annick , Maucourt Mickaël , Renaud Christel , Gaudillère Monique , Brouquisse Renaud , Lebouteiller Bénédicte , Gousset-Dupont Aurélie , Vidal Jean , Granot David , Denoyes-Rothan Béatrice , Lerceteau-Köhler Estelle , Rolin Dominique
Published: December 2004

Metabolic profiling by 1-dimensional (1-D) 1H-nuclear magnetic resonance (NMR) was tested for absolute quantification of soluble sugars, organic acids, amino acids and some secondary metabolites in fruit, roots and leaves. The metabolite responsible for each peak of the 1H-NMR spectra was identified from spectra of pure compounds. Peak identity was confirmed by the addition of a small amount of commercially-available pure substance. 1H-NMR spectra acquisition was automated. 1H-NMR absolute quantification was performed with a synthesised electronic reference signal and validated by comparison with enzymatic or HPLC analyses; the correlation coefficients between 1H-NMR data and enzymatic or HPLC data were highly significant. Depending on the species and tissues, 14–17 metabolites could be quantified with 15–25 min acquisition time. The detection limit was approximately 1–9 µg in the NMR tube, depending on the compound. Quantitative data were used for (1) a genetic study of strawberry fruit quality, (2) a functional study of tomato transformants overexpressing hexokinase and (3) a study of Arabidopsis phosphoenolpyruvate carboxylase transformants with several lines showing decreased activity of the enzyme. Biochemical phenotyping of the fruits of a strawberry offspring allowed the detection of quantitative trait loci (QTL) controlling fruit quality. Comparison of the roots of wild types and hexokinase tomato transformants using principal component analysis of metabolic profiles revealed that environmental factors, i.e. culture conditions, can significantly modify the metabolic status of plants and thus hide or emphasise the expression of a given genetic background. The decrease in phosphoenolpyruvate carboxylase activity (up to 75%) in Arabidopsis transformants impacted on the metabolic profiles without compromising plant growth, thus supporting the idea that the enzyme has a low influence on the carbon flux through the anaplerotic pathway.
Phylogeny of protein-folding trajectories reveals a unique pathway to native structure
Authors: Ota Motonori , Ikeguchi Mitsunori , Kidera Akinori
Published: December 2004

To scrutinize how a protein folds at atomic resolution, we performed 200 molecular dynamics simulations (each of 50 ns) of the miniprotein Trp-cage on the computational grid. Within the trajectories, 58 folding and 31 unfolding events were identified and subjected to extensive comparison and classification. Based on an analogy with biological sequences, the folding and unfolding trajectories (arrays of sequential snapshots of structures) were aligned by dynamic programming allowing gaps. A phylogenetic tree derived from the alignments revealed four distinct groups of the trajectories, characterized by the Trp side-chain motions and the main-chain motions. It was found that only one group attained the native structure and that the other three led to pseudonative structures having the correct main-chain trace but different nonnative Trp side-chain rotamers, indicating that those four folded structures were each attained through a unique folding pathway.
Vibration pattern of the organ of Corti up to 50 kHz: Evidence for resonant electromechanical force
Authors: Scherer Marc P. , Gummer Anthony W.
Published: December 2004

Electromechanical force derived from the soma of the outer hair cell has long been postulated as the basis of the exquisite sensitivity of the cochlea. The problem with this postulate is that the electrical source and mechanical load for the electromechanical outer hair cell might be severely attenuated and phase-shifted by the electrical impedance of the cell and the mechanical impedance of the organ of Corti, respectively. Until now, it has not been possible to experimentally derive the high-frequency electrically induced force at the reticular lamina when the cells are embedded within the organ of Corti. In the study reported here, we succeeded in determining the frequency spectrum of the force up to 50 kHz. This was achieved by measuring both the electrically induced velocity and the mechanical impedance at different radial positions on the reticular lamina without tectorial membrane and with clamped basilar membrane. Velocity was measured with a laser interferometer and impedance, with a magnetically driven atomic force cantilever. The electromechanical force, normalized to the electric current density, exhibited a broad amplitude maximum at 7–20 kHz with a quality factor,
Q
3dB
, of 0.6 - 0.8. The displacement response was independent of frequency up to 10–20 kHz. The force response compensates for the viscoelastic impedance of the organ of Corti, extending the amplitude response of the organ to high frequencies. It is proposed that the electrical phase response of the cell is compensated with Zwislocki's original mechanism of a parallel resonance in the tectorial membrane–stereocilia complex.
Studying multiprotein complexes by multisignal sedimentation velocity analytical ultracentrifugation
Authors: Balbo Andrea , Minor Kenneth H. , Velikovsky Carlos A. , Mariuzza Roy A. , Peterson Cynthia B. , Schuck Peter
Published: December 2004

Protein interactions can promote the reversible assembly of multiprotein complexes, which have been identified as critical elements in many regulatory processes in cells. The biophysical characterization of assembly products, their number and stoichiometry, and the dynamics of their interactions in solution can be very difficult. A classical first-principle approach for the study of purified proteins and their interactions is sedimentation velocity analytical ultracentrifugation. This approach allows one to distinguish different protein complexes based on their migration in the centrifugal field without isolating reversibly formed complexes from the individual components. An important existing limitation for systems with multiple components and assembly products is the identification of the species associated with the observed sedimentation rates. We developed a computational approach for integrating multiple optical signals into the sedimentation coefficient distribution analysis of components, which combines the size-dependent hydrodynamic separation with discrimination of the extinction properties of the sedimenting species. This approach allows one to deduce the stoichiometry and to assign the identity of the assembly products without prior assumptions of the number of species and the nature of their interaction. Although chromophoric labels may be used to enhance the spectral resolution, we demonstrate the ability to work label-free for three-component protein mixtures. We observed that the spectral discrimination can synergistically enhance the hydrodynamic resolution. This method can take advantage of differences in the absorbance spectra of interacting solution components, for example, for the study of protein–protein, protein–nucleic acid or protein–small molecule interactions, and can determine the size, hydrodynamic shape, and stoichiometry of multiple complexes in solution.
TheAlabamaClaims Arbitration
Authors: Bingham Tom
Published: December 2004

A lecturer on theAlabamaclaims and the Geneva Tribunal of 1871–2, like a director ofHamlet, has to accept one inescapable fact: that everyone knows, broadly at least, how the story ends. There can be no reliance on suspense to sustain interest in the narrative. So I shall begin at the end.
Uncertainties in the First Limb of the Spiliada Test
Authors: Merrett Louisec
Published: December 2004

Lord Goff formulated the first stage of his classic test in the Spiliada in the following terms: ‘the basic principle is that a stay will only be granted on the ground of forum non conveniens where the court is satisfied that there is some available forum, having competent jurisdiction, which is the appropriate forum for the trial of the action’ (emphasis added).
Method and Objectivity in Free Speech Adjudication: Lessons from America
Authors: Hare Ivan
Published: December 2004

Following a dispute with his black neighbour, a white man in Virginia erects and ignites a crude home-made cross on the neighbouřs lawn. The white man is convicted under a law prohibiting intimidation by use of a burning cross.
Children's early theory of mind: exploring the development of the concept of desire in monolingual Spanish children
Authors: Ferres Leo A.
Published: December 2004

This paper presents the results of an analysis of the lexical term ‘querer’ (want) qua genuine reference to desire. The instances of ‘querer’ to be analyzed were taken from the naturally occurring speech of monolingual speakers of Spanish. Specifically, a database of 24,558 child utterances taken from the CHILDES system was analyzed. This corpus yielded 444 utterances with the desire term ‘querer’. The utterances belong to several children whose ages range from 21 to 46 months. The results of this study support the hypothesis that children consistently refer to desire at around 2 years of age and that children undergo a marked increase in their reference to this concept at 36 months of age, although it is not yet clear whether they start referring to their own desires before those of someone else.
Real Time, Accurate, Multi‐Featured Rendering of Bump Mapped Surfaces
Authors: Tarini M. , Cignoni P. , Rocchini C. , Scopigno R.
Published: December 2004

We present a new technique to render in real time objects which have part of their high frequency geometric detail encoded in bump maps. It is based on the quantization of normal‐maps, and achieves excellent result both in rendering time and rendering quality, with respect to other alternative methods. The method proposed also allows to add many interesting visual effects, even for object with large bumb maps, including non‐s rendering, chrome effects, shading under multiple lights, rendering of different materials within a single object, specular reflections and others. Moreover, the implementation of the method is not complex and can be eased by software reuse.
Feature Model Visualization
Authors: Bronsvoort Willem F. , Bidarra Rafael , Noort Alex
Published: December 2004

Feature modelling is now the predominant way of modelling products. Feature visualization is an important aspect here that can still be considerably improved. In this paper, an integrated way of visualizing feature models is presented, using new techniques for both the geometry and the structure of models. For the geometry of feature models, techniques are presented to visualize a selected subset of form features in a way that clearly distinguishes them from the rest of the model, as well as functional information such as closure faces of subtractive form features. For the structure of features models, techniques are presented to visualize several types of graphs. The different visualization techniques are used in an integrated way. Implementation of some of the techniques requires a non‐manifold representation of the geometry of the feature model. This representation, and some other implementation aspects, are briefly described. Throughout the paper, numerous examples of images of feature models are given which show that the new visualization techniques can indeed improve the effectiveness of feature modelling.

ACM CSS: I.3.7 Three‐Dimensional Graphics and Realism—visible line/surface algorithms, J.6 Computer‐AidedEngineering—feature modelling
An algorithm for line clipping against a polygon based on shearing transformation
Authors: Huang Y. Q. , Liu Y. K.
Published: December 2004

Line clipping against a polygon is widely used in computer graphics such as the hidden line problem. A newline‐clipping algorithm against a general polygon is presented in this paper. The basic idea of this algorithm is tochange the line to be clipped into a horizontal line by shearing transformation. Then each edge of the polygonalwindow is transformed by a shearing transformation with the same parameters as those used to the line. Eachedge of the polygon is processed against a horizontal line, which makes the clipping process simpler. The result inthis paper shows that less calculation is needed for the new algorithm with a higher speed compared to existingalgorithms.
A Skeleton‐based Approach for Detection of Perceptually Salient Features on Polygonal Surfaces
Authors: Hisada Masayuki , Belyaev Alexander G. , Kunii Tosiyasu L.
Published: December 2004

The paper presents a skeleton‐based approach for robust detection of perceptually salient shape features. Given ashape approximated by a polygonal surface, its skeleton is extracted using a three‐dimensional Voronoi diagramtechnique proposed recently by Amenta et al. [3]. Shape creases, ridges and ravines, are detected as curvescorresponding to skeletal edges. Salient shape regions are extracted via skeleton decomposition into patches.The approach explores the singularity theory for ridge and ravine detection, combines several filtering methodsfor skeleton denoising and for selecting perceptually important ridges and ravines, and uses a topological analysisof the skeleton for detection of salient shape regions.

ACM CSS: I.3.5 Computational Geometry and Object Modeling
An Efficient Method for Rendering Underwater Optical Effects Using Graphics Hardware
Authors: Iwasaki Kei , Dobashi Yoshinori , Nishita Tomoyuki
Published: December 2004

The display of realistic natural scenes is one of the most important research areas in computer graphics. Therendering of water is one of the essential components. This paper proposes an efficient method for renderingimages of scenes within water. For underwater scenery, the shafts of light and caustics are attractive and importantelements. However, computing these effects is difficult and time‐consuming since light refracts when passingthrough waves. To address the problem, our method makes use of graphics hardware to accelerate the computation.Our method displays the shafts of light by accumulating the intensities of streaks of light by using hardware colorblending functions. Making use of a Z‐buffer and a stencil buffer accelerates the rendering of caustics. Moreover,by using a shadow mapping technique, our method can display shafts of light and caustics taking account ofshadows due to objects.

ACM CSS: I. 3.1 Computer Graphics—Hardware Architecture, I. 3.7 Computer Graphics—Three‐DimensionalGraphics and Realism
Hierarchical Impostors for the Flocking Algorithm in 3D
Authors: O'Hara Noel
Published: December 2004

The availability of powerful and affordable 3D PC graphics boards has made the rendering of rich immersiveenvironments possible at interactive speeds. The scene update rate and the appropriate behaviour of objects withinthe world are central to this immersive feeling. This paper is concerned with the behaviour computations involvedin the flocking algorithm, which has been used extensively to emulate the flocking behaviour of creatures found innature. The main contribution of this paper is a new method for hierarchically combining portions of the flocksinto groups to reduce the cost of the behavioural computation, allowing far larger flocks to be updated in real‐timein the world.

ACM CSS: I.3.7 Three‐Dimensional Graphics and Realism—Animation
Levels of Detail for Crowds and Groups
Authors: O'Sullivan C. , Cassell J. , Vilhjálmsson H. , Dingliana J. , Dobbyn S. , McNamee B. , Peters C. , Giang T.
Published: December 2004

Work on levels of detail for human simulation has occurred mainly on a geometrical level, either by reducing the numbers of polygons representing a virtual human, or replacing them with a two‐dimensional imposter. Approaches that reduce the complexity of motions generated have also been proposed. In this paper, we describe ongoing development of a framework for Adaptive Level Of Detail for Human Animation (ALOHA), which incorporates levels of detail for not only geometry and motion, but also includes a complexity gradient for natural behaviour, both conversational and social.

ACM CSS: I.3.7 Three‐Dimensional Graphics and Realism—Animation
Synthetic Vision and Memory for Autonomous Virtual Humans
Authors: Peters C. , O'Sullivan C.
Published: December 2004

A memory model based on ``stage theory'', an influential concept of memory from the field of cognitive psychology,is presented for application to autonomous virtual humans. The virtual human senses external stimuli througha synthetic vision system. The vision system incorporates multiple modes of vision in order to accommodate aperceptual attention approach. The memory model is used to store perceived and attended object information atdifferent stages in a filtering process. The methods outlined in this paper have applications in any area wheresimulation‐based agents are used: training, entertainment, ergonomics and military simulations to name but afew.

ACM CSS: I. 3.7 Computer Graphics‐‐Virtual reality
Towards Interactive Real‐Time Crowd Behavior Simulation
Authors: Ulicny Branislav , Thalmann Daniel
Published: December 2004

While virtual crowds are becoming common in non‐real‐time applications, the real‐time domain is still relativelyunexplored. In this paper we discuss the challenges involved in creating such simulations, especially the needto efficiently manage variety. We introduce the concept of levels of variety. Then we present our work oncrowd behaviour simulation aimed at interactive real‐time applications such as computer games or virtualenvironments. We define a modular behavioural architecture of a multi‐agent system allowing autonomous andscripted behaviour of agents supporting variety. Finally we show applications of our system in a virtual realitytraining system and a virtual heritage reconstruction.

ACM CSS: I.3.7 Three‐Dimensional Graphics and Realism—Animation, I.2.11 Distributed ArtificialIntelligence—Multi‐agent systems
The textual transmission of the Mozarabic Chronicle of 754
Authors: De Hartmann Carmen Cardelle
Published: December 2004

The so‐called Mozarabic Chronicle of 754 is a work of extraordinary value for the history of the Arab conquest of Spain since it is an eyewitness account of the events. Because of the difficulty it presents, the text was largely neglected by historians, until two recent editions, translations into Spanish and English and several studies have returned it to the central place it deserves as a source for the eighth century. In this article I want to look at some aspects of its textual history which have not previously been studied in sufficient depth, for the light they shed both on the circulation of historical works in medieval Spain and on the history of two mysterious codices, a Mozarabic manuscript of which only six folios remain, and the lost Alcobaciensis manuscript.
Some churches of the Anglo‐Saxon missionaries in southern Germany: a review of the evidence
Authors: Parsons David
Published: December 2004

An historical introduction outlines the main events in the lives of the principal missionaries – Willibald, Wynnebald, Waldburga, Sola – during the central years of the eighth century, and argues that Willibald was consecrated bishop of Erfurt. A review of the topographical and archaeological evidence concentrates on Eichstätt, whose street pattern reveals the layout of the early town and monastery; new interpretations are suggested for unusual features uncovered by excavation at the cathedral/monastery site. The excavations at Solnhofen are similarly re‐examined. Overall, no substantial evidence is found for Anglo‐Saxon influence on the church archaeology of the area.
Changing views of Carolingian women's literary culture: the evidence from Essen
Authors: Stofferahn Steven A.
Published: December 2004

This article endeavours to show that much of what has been considered ‘exceptional’ in Carolingian women's literary culture had in fact a much wider purview. An examination of key elements of a ninth‐century codex illuminates the continuity between the manuscript's creators and intended audience, providing plausible evidence for female involvement in the production and utilization of intricate literary compilations and, thus, also for a more inclusive role for women in the Carolingian Renaissance.
‘Nostrorum socordiam temporum’: the reforming impulse of Bede’s later exegesis
Authors: DeGregorio Scott
Published: December 2004

This paper attempts to provide a synoptic view of the thematic development of Bede’s exergesis. It examines a selection of his commentaries written at different periods in his career and, by placing them against the social and political background of early eighth–century Northumbria, tries to indicate some important differences amongst them. The core of my argument is that, in contrast to his early commentaries, Bede’s mature exegesis is decisively infused by the aims and concerns of his later non–exegetical works such as the Ecclesiastical History and the Letter to Ecgberht. It will be shown, for example, that earlier commentaries such as On the Apocalypse and On Acts devote less attention to pastoral concerns than do such later works as On Ezra and Nehemiah, On the Tabernacle and On the Temple. Further, the earlier commentaries contain fewer topical comments on the social and religious demise of contemporary Northumbria than the later exegesis (especially On Ezra and Nehemiah), comments whose substance and tone align this later work with the reform program of the Ecgberht letter. By considering these and other related issues, my analysis has a twofold aim: to provide a better sense of the overall shape and development of Bede’s commentaries, and to highlight the social investedness and intertextuality of his later writings as a whole.
Will Free Trade with Political Science Put Normative Economists Out of Work?
Authors: O'Flaherty B. , Bhagwati J.
Published: December 2004

Telling governments what to do is an ancient and important tradition in economics. Predicting what governments will do, i.e., endogenizing policy, is a newer activity, but one of growing prominence. The two activities appear incompatible: if what governments do is the result somehow of equilibrium behavior of self‐interested actors, then advising governments is as senseless an activity as advising monopolists to lower prices or advising the San Andreas fault to be quiet. We show why and how advising can sometimes be a sensible activity, even when we hold sophisticated views about how governments operate.
The Credibility of the PRC Commitment to a Market Economy in Hong Kong: Hypotheses and Evidence
Authors: Newman D. , Weimer D. L.
Published: December 2004

How credible is China's commitment to a market economy in Hong Kong after 1997? Events signaling changes in commitment and the movement of time closer to 1997 should reduce the relative prices of immobile assets if commitment is not fully credible. Several factors may offset these effects: anticipatory adaption, growing dependence on China‐related trade, and Chinese investment in Hong Kong. Analysis of data on incorporation and investment decisions, the relative sensitivity of the stock prices of firms with different asset mobility to political events, and the market for office space most strongly support hypotheses about credibility, adaption, and demand augmentation.
To Shock or Not to Shock? Economics and Political Economy of Large‐Scale Reforms
Authors: Lian P. , Wei S.‐J.
Published: December 2004

This paper studies the economics and political economy of optimal scale of reforms. The aim of the reform is to replace inefficient existing institutions by the more efficient new ones. The optimal scale of reform, in general, differs from a shock therapy that replaces the old institutions all at once. Furthermore, if agents in the economy are heterogeneous in terms of their subjective discount rates, the politically‐determined reform speed may be lower in a democracy than in an economy with a benevolent dictator.
Political Competition in Weak States
Authors: La Ferrara Eliana , Bates Robert H.
Published: December 2004

In the developing areas, politics is often undemocratic, states lack a monopoly over violence, and politicians play upon cultural identities. To analyze politics in such settings, we develop a model in which politicians compete to build a revenue yielding constituency. Citizens occupy fixed locations and politicians seek to maximize rents. To secure revenues, politicians must incur the costs of providing local public goods and mobilizing security services. Citizens must participate, i.e. pay taxes; but can choose which leader to support. The model enables us to explore the impact of cultural identities and varying notions of military power.
A Model of Inequality and Interest Group Politics
Authors: Kohli Inderjit , Singh Nirvikar
Published: December 2004

In this paper we examine inequality of process and inequality of outcomes in interest group politics. The model has interest groups that compete for rents in a non‐cooperative game. It allows for a self‐interested rent‐setting political decision‐maker, and democratic or popular pressure as a check on that self‐interest. We consider differences in the effectiveness and pre‐commitment abilities of interest groups. We show that: (i) the costs of influence activities may be highest when groups are relatively equal in their effectiveness; (ii) if social welfare incorporates enough concern for equity of outcomes, that ranking is reversed; (iii) depending on voter responsiveness to rent‐setting, the political decision‐maker may set rents to be higher or lower, when increases in inequality of effectiveness lower the unit costs of rent‐seeking.
The Political Economy of the IRS
Authors: Young Marilyn , Reksulak Michael , Shughart William F.
Published: December 2004

This paper tests a multiple principal–agent model of the Internal Revenue Service. Using data for 33 IRS districts over six tax years, 1992–1997, we report evidence that the fraction of individual income tax returns audited is significantly lower in districts that are important to the president electorally and that have representation on key congressional committees. These findings suggest that the IRS is not a rogue government agency, but rather is an effective bureaucratic agent of its political sponsors. “Reforming” the IRS by subjecting it to an independent oversight board appointed by the president would therefore seem to be redundant.
Some empirical tests on the integration of economic activity between the euro area and the accession countries
Authors: Korhonen Iikka
Published: December 2004

This note looks at the correlation of short‐term business cycles in the euro area and the EU accession countries. The issue is assessed with the help of vector autoregressive models. There are clear differences in the degree of correlation between accession countries. For Hungary and Slovenia, euro area shocks can explain a large share of variation in industrial production, while for some countries this influence is much smaller. For the latter countries, the results imply that joining the monetary union could entail reasonably large costs, unless their business cycles converge closer to the euro area cycle. Generally, for smaller countries the relative influence of the euro area business cycle is larger. Also, it is found that the most advanced accession countries are at least as integrated with the euro area business cycle as some small present member countries of the monetary union.

JEL classification: E32, F15, F42.
The reallocation of workers and jobs in Russian industry
Authors: David Brown J. , Earle John S.
Published: December 2004

Gross job and worker flows in Russian industry are studied using panel data from a survey of 530 firms selected through national probability sampling. The data permit examination of several crucial measurement issues, including the timing and definition of employment and the role of reorganizations, and they contain rich information on firm characteristics. We find that new and reorganized firms display larger flows than unreorganized enterprises. Product market dispersion and managerial and dispersed outsider ownership are associated with greater worker churning, and unionization and concentrated outsider ownership with less.

 There is little evidence that the average firm's employment adjustments have become more responsive to adjustment costs during the transition, but private ownership and product market competition appear to increase responsiveness.

JEL Classifications: E24, J23, J63, P23, P31.
The Free Movement of Goods as a Possible ‘Community’ Limitation on Industrial Conflict
Authors: Orlandini Giovanni
Published: December 2004

The aim of this essay is to underline the fact that the process of achieving single market integration is very likely to influence the regulation of industrial conflict. In this perspective, the Commission v France judgment is analysed, in which the ECJ—through a combined interpretation of Article 30 (now 28) and Article 5 (now 10) of the Treaty—states that a Member State is obliged to adopt all ‘appropriate measures’ to remove any ‘obstacles’ impeding the free circulation of goods caused by private persons. A new Regulation (n. 2679/98) has followed the ECJ decision, instituting a system of notification of such obstacles arising, or the threat of them, and the right of the Commission to demand a formal reply from a State on whether it has taken, or will be taking the necessary and proportionate measures.

The analysis of the principles adopted by the ECJ and of the Regulation shows that, at Community level, pressure is exerted on States to prevent the exercise of collective action as effectively as possible, if this damages inter‐State trade. A transnational limit on industrial conflict thus emerges in the Community order, which may well affect the equilibria of national industrial relations in various ways.
The Reconstitution of European Public Spheres
Authors: Chalmers Damian
Published: December 2004

The strength of participation in its political processes has increasingly become the yardstick against which the legitimacy of the European Union is measured. Yet experiments in deliberative and participatory democracy suggest that their practice invariably falls short of their lofty ideals. A reason is their failure to consider the process of communication itself. As understanding of communication is constituted through a number of surrounding communicative contexts, communication, per se, can never be said to be good or bad. More important is a constitutional framework for communication which provides the contexts—performative, institutional and epistemic—that enable communication to contribute to particular, desirable ideals. This piece will argue that a deliberative approach to European governance involves a process of justification in which the three practical tasks of the European Union—polity‐building, problem‐solving and the negotiation of political community—are debated and resolved around the four values that have underpinned the development of politics as a productive process—those of transformation, validity, relationality and self‐government. The organisational reform required for this involves a wide‐ranging revisiting of the structures of the European polity.
European Civil Society: Shaped by Discourses and Institutional Interests
Authors: Smismans Stijn
Published: December 2004

Abstract: During recent years, the concept of European civil society has gained increasing popularity. The European Institutions themselves have developed a discourse on civil society and civil dialogue. Institutional interests have shaped this discourse. Reframing the normative context for EU democracy, this discourse suits some institutions better than others. In particular, the European Economic and Social Committee and the European Commission have made recourse to it; the former to redefine its proper role and combat the risk of marginalisation within the European institutional set‐up; the latter first to build support for policy initiatives in the social sphere and subsequently to respond to the legitimacy crisis of the Brussels’ bureaucracy. These institutional interests have inspired a conceptualisation of civil society as ‘functional participation’ and ‘functional representation’ rather than as ‘politicisation’ or ‘decentralisation’. However, while the Commission and the ESC have had some success in selling their discourse, to be successful in the longer run some problematic assumptions of the discourse should be tackled and both the different rationales for civil society involvement as well as the multi‐level character of European civil society and European policymaking should be taken into account.
REDSIEX: A Cooperative Network of Expert Systems with Blackboard Architectures
Authors: González Pérez Pedro Pablo , Martínez José Negrete
Published: December 2004

The blackboard architecture, originally developed for the system that permits the comprehension of language, HEARSAY II, has later been used in a great variety of domains and in various environments for the construction of systems. From the classic architecture of HEARSAY II, many applications, generalizations, extensions and refinements have been developed. In this paper we present REDSIEX, (RED de SIstemas EXpertos) which is a network of expert systems within a blackboard architecture, for the cooperation solution of distributed problems. The REDSIEX system inherits various of the elements defined by the architecture of HEARSAY II and incorporates new components and organization. These produce a very characteristic and exclusive global work style in the solution of problems, within a conceptual framework of emergent control. The main structural and functional characteristics of REDSIEX are discussed.